This PDF file contains the front matter associated with SPIE Proceedings Volume 11338, including the title page, copyright information, table of contents, and author and conference committee lists.

For most Earth observation spacecrafts (EOS), repeating sun-synchronous orbit is a preferred working orbit for the Earth observation spacecraft. Repeating ground trace can provide an ideal observation geometry for space-crafts devoted to Earth observation missions. Sun-synchronous orbit can provide an ideal supply of solar power for the space-crafts. Payloads for EOS usually need demanding pointing stability. One of the main factors which may lead to the variation of payload pointing is the solar radio flux. In different year, the solar radio flux varies. This paper focuses on the characteristics of payload pointing stability due to the variation of the solar radio flux. As historic dataset, solar radio flux shows periodic change of 11 years. In 11 years, solar radio flux experiences the maximal and the minimal solar flux units (sfu). In the case of the payload beam boresight, the simulation results indicate that during the year of severe solar activity with 230sfu, 4 months of orbit drifting without any orbit maneuver will result in payload pointing change less than ±2 deg, and that during the year of severe solar activity with 230 sfu, 2 months of orbit drifting without any orbit maneuver will result in payload pointing change less than ±0.5 deg. And the simulations also indicate that during the year of average solar activity with 150sfu, 4 months of orbit drifting without any orbit maneuver will result in payload pointing change less than ±0.5 deg, and that during the year of average solar activity with 150sfu, 2 months of orbit drifting without any orbit maneuver will result in payload pointing change less than ±0.1 deg; In the case of the payload beam edge, the simulation results indicate that during the year of severe solar activity with 230sfu, 4 months of orbit drifting without any orbit maneuver will result in payload pointing change less than ±5 deg, and that during the year of severe solar activity with 230 sfu, 2 months of orbit drifting without any orbit maneuver will result in payload pointing change less than ± deg. And the simulations also indicate that during the year of average solar activity with 150sfu, 4 months of orbit drifting without any orbit maneuver will result in payload pointing change less than ±2 deg, and that during the year of average solar activity with 150sfu, 2 months of orbit drifting without any orbit maneuver will result in payload pointing change less than ±0.5 deg; The simulations provide an effective constraint of orbit maneuver scenario planning, and further boost the feasibility of space-crafts engineering.

Dynamic range is an important criterion for measuring the quality of CMOS image sensors, which is used to describe the ability of sensors in the detected scene to reflect the bright part and the dark part. In this paper, the research of CMOS dynamic range lifting technology is carried out, and the multiple slope integration technique of conditional reset is expounded in detail, and the experimental verification is carried out on CMOS camera system based on CMV20000. The experimental results show that the multiple slope integration technique can significantly improve the dynamic range of CMOS images.

In order to break through the limitations of super-miniaturization, super-long focal length and super-wide field of view on optical system, a miniaturized four field of view medium-wave infrared optical system is proposed and designed. The optical system adopts double optical path structure, including super-small field of view optical path and small field of view/medium field of view/wide field of view optical path. Two optical paths share a relay group. The super-small field of view optical path is stereo-folded four times, and the small/medium/wide field of view optical path is folded twice, totally six times. The shape size of the whole dual paths optical system is effectively constrained, and the envelope is in the range of 250mm×155mm×90mm (local 140 mm), the optical system has high integration; the dual-path optical system includes four fields of view: super-small field of view, small field of view, medium field of view and wide field of view. The super-small field of view focal length is 733mm, the field of view is 0.75 degrees, the wide field of view focal length is 10.78 mm, and the field of view is 48 degrees, which realizes both super-long focal length and super-wide field of view with a zoom ratio of 68× and the super-small field of view optical system only adopts with five lenses, the transmittance is high, and the whole optical system with two optical paths has compact structure and small volume, thus realizing the miniaturization. The design and test results show that the optical system has good image quality and meets the requirements of high performance thermal imager.

In the liquid crystal spatial light modulator, creating overdriving look-up table is a cumbersome process. A large number of experiments are needed to measure the driving time between different target phases and the final phase, and the overdrive look-up table occupies excessive memory space that slow down the response speed of the liquid crystal. Aiming at the problems above, an establishment method of overdriving look-up table is put forward. The method uses PWM driving and curve fitting, only two response time curves measured will complete the calculation of the entire drive table, which solves the problem of the complicated experiment of overdriving table construction. Finally, choosing the appropriate quantization wavelength to optimize the overdriving table, effectively improving the accuracy of the drive table and the maintainability and scalability of the system, and it is more suitable for engineering applications.

The nBn barrier medium-wave infrared detector is widely used in the field of night defense vision with internal gain. Due to its low dark current and high reliability. As the existence of its barrier layer suppresses the majority carrier current with a low electric field, the electric field distribution inside the device is one of the important factors affecting its performance. In particular, the electric field distributions of the barrier layer show directly effects on the overall performance of the detector. In this paper, Apsys software is used to simulate the absorption layer and the nBn InAs1-xSbx/AlAs1-ySby mid-wave infrared detector with the factors of thickness, composition and doping changes. and the influence of the above factors on the electric field of the device is also analyzed.

PLZT is an excellent electro-optic material. The anti-glare goggles composed of PLZT and driving circuit have a good application in strong laser protection. With the increasing popularity of anti-glare PLZT goggles, the measurement of the photoelectric parameters of PLZT goggles becomes important. This article aims to develop an optoelectronic parameter measuring system for the anti-glare PLZT goggles. When the change of the illuminance or the illuminance of the light incident on the PLZT surface reaches a certain threshold, the PLZT driving circuit quickly controls the change of the working state of the PLZT and reduces the light transmittance of the PLZT. Avoid blindness or eyes burns during strong flashes. After the strong flash is over, the light transmittance can be automatically restored to normal conditions within a certain period of time. In this paper, the integrating sphere and high-power LED are used as the light source to generate uniform glare, and the microcontroller is used to control the output optical power. Two output windows are arranged on the integrating sphere, one is used to detect the actual output illuminance of the integrating sphere, that is the illuminance of the surface incident on the PLZT surface, and the PLZT to be detected is placed after the other window, and the illuminance after entering the PLZT is detected. Two photodiodes are used to detect the illuminance of the two beams, and the two results are used to calculate the light transmittance and change time through the PLZT.

Gene biochip imaging and scanning technology is a more advanced gene diagnosis technology after fluorescence quantitative PCR technology, second-generation sequencing technology and digital PCR technology. Due to the great influence of fluorescence microscopy system, the imaging and scanning technology of gene biochip with high imaging efficiency and accuracy has become a hot topic widely concerned by scholars. In this paper, two-channel laser was used as the excitation light source of the biochip, and the fluorescence imaging system of the switchable fluorescence filter was designed to realize the detection of FAM and HEX biological fluorescence signals; According to the working principle of the gene biochip imager, the finite element analysis method is used to analyze the thermal structure of the optical system, and the internal structural parameters of the optical system are optimized according to the simulation results. According to the optimization result, the illumination time of each object pixel is controlled to utilize the fluorescence information more efficiently, and the fluorescent bleaching effect is reduced without sacrificing the image quality, and the PCR amplification oil droplet quantitative reading and display is performed in real time. The gene biochip imaging system proposed in this paper can be used to image, obtain, read, process and display the detected chip with a resolution of 10 m/ pixel, a minimum detection limit of < 10 fluorescent molecules/square micron, and a sample detection repeatability of < 10%.The results show that the gene biological chip imaging system designed by this research has the advantages of low noise, low cost and fast scanning speed, and provides a theoretical basis for precision medical fields such as early diagnosis and cure evaluation of clinical tumors. The results show that the gene biochip imaging system designed by this research has the advantages of low noise, low cost and fast scanning speed, and provides a theoretical basis for precision medical fields such as early diagnosis and cure evaluation of clinical tumors.

Wide-angle Synthetic Aperture Radar (WSAR) imaging accounts for multi-azimuthal scattering and is feasible for retrieving more comprehensive features of complex targets. This paper proposes a civilian vehicle target discrimination algorithm. The algorithm firstly images the vehicle target data separately for each azimuth, and then calculates the local representative point of each sub-image to generate a spiral three-dimensional point cube of the target attributed scattering centers. The point cube contains both the attributed scattering centers and azimuth information of the target, so it is easier to classify than the two-dimensional imaging without azimuth. Manifold learning methods can be used to reduce the dimension of spiral three-dimensional point cube to two dimensions. A simple and fast loose iterative Multi- Dimensional Scaling (MDS) algorithm for dimensionality reduction is presented in this paper. Finally, the Convolution Neural Network (CNN) is used to train the two-dimensional attributed scattering centers with azimuth information, and the discrimination results are obtained. The proposed method is demonstrated on Gotcha WSAR dataset.

High precision star sensor can indirectly gain the information of attitude and orbit by refracted starlight, so that spacecraft can navigate and position autonomously. Due to the high cost of spacecraft launch and development, the functional validation of this technology relies mainly on the ground simulation tests and experiments. At present, less attention is paid to the study on refraction star-map simulation method, and the simulation effects of the existing implementation methods are difficult to meet the engineering requirements. Firstly，by combing the autonomous navigation principle and mathematical model of starlight atmospheric refraction, based on the situation that effective starlight refraction occurs in stratosphere space, a mapping band of refracted starlight is put forward. Then, through three steps including the critical condition of starlight refraction happens in the stratosphere space, the determination method of refracted starlight vector and the angle range of star sensor boresight pointing when the refraction stratosphere space enters the field of view (FOV), a method on refraction star-map simulation proposed in this paper is described in detail. Finally, with the help of MATALB, the refraction star-map simulation is achieved and a sharp contrast of the mapping coordinates of starlight vectors with/without refraction is given, and the effect of simulated star-map is excellent. This method has important engineering application value.

The type-II InAs/GaSb superlattices have been recognized as popular materials for the third-generation infrared focal plane detectors. In recent years, the performances of the type ii superlattice infrared focal plane have been improved dramatically. High operating temperature can be achieved by using the monopolar barrier structure of InAs/GaSb type ii superlattice material system. In this paper, the nBn type (also known as Bariodes) mid-wavelength infrared detector based on InAs/GaSb type ii superlattice is studied. As the device has no depletion layer, the recombination and trap assisted tunneling effects are inhibited, and the dark currents are effectively reduced. Based on the equivalent material method, the relationship between the dark current and the doping concentration, thickness and composition of the barrier layer and absorption layer was analyzed in detail, and the optimal working condition was pointed out.

Supersonic cooling film can reduce the influence of aerodynamic heating to a certain extent, but the complex flow field structure formed by its interaction with the mainstream will cause imaging target offset, ambiguity and jitter, that is, aero-optical effect. In this paper, the variation of cooling efficiency and aero-optical effect at the optical window under different jet States is studied numerically, and the validity of the numerical method is verified by comparing the experimental results. The results show that the cooling efficiency at the optical window is higher and the aero-optical effect is smaller because of the proper total temperature of the cooling jet; The higher the supply pressure of cooling gas, the better the cooling efficiency of film cooling. In order to ensure the weakest aero-optical effect, the cooling gas supply is in pressure matching state; With the increase of Mach number of cooling gas injection, the cooling efficiency and aero-optical effect of supersonic film cooling increase; In general, nitrogen or air is chosen as cooling gas.

Responsivity is one of the important technical parameters of the detector. With the development of ultraviolet detector technology, ultraviolet focal plane array devices have also been rapidly developed. Therefore, it is increasingly important to accurately measure the response of ultraviolet detectors. This paper analyzes the principle of UV focal plane array response measurement, uses the alternative method to measure the response of the UV focal plane array detection device, and establishes the UV focal plane array response measurement device. The results of uncertainty analysis show that the uncertainty of the UV focal plane array device response measurement system is about 4.2 %, can meet the measurement requirements.

Cryogenic radiometer is considered as the international benchmark for optical power measurement, which requires the core light radiation receiving device (cavity) has high absorption coefficient over 0.9999 at presented. In this paper, we have developed a new cavity are made of oxygen-free high-conductivity copper (OFHC) cylinder and coated with nickel-phosphorus (NiP) black paint. The cavity absorptance has been experimentally evaluated at different black paints and different structures. The result shows that the inclined bottom cylindrical cavity blackened with nickel-phosphorus black paint achieves an absorptance up to 0.9999964±0.000005; The most significant improvements in uncertainty arise from the enhanced characteristics of the cryogenic radiometer including its higher cavity absorptance and reduced non-equivalence effects.

We propose fast, economical one-shot optical sectioning structured illumination microscopy (OSSIM) based on the sectioning structured illumination wide-field fluorescence microscopy (SSIWM). Unlike using three precise known phase patterns in conventional three-step SSIWM, every section of the specimen is modulated using a one-dimensional sinusoidal pattern with an arbitrary phase in the proposed method. There are few steps to get the section image from the modulated image. A fringe-free spectrum is obtained using a filter in the Fourier domain, and the reconstructed section is recovered from its inverse Fourier transform and the modulus calculation. In the conventional SSIWM, the accurate positioning is demanded to match the three phases perfectly to avoid artificial fringe on the reconstructed image. Compared with three-step SSIWM, OSSIM shows reduced illumination and observation time, specimen damage, and it avoids reconstruction artefacts resulting from inaccurate phase-shift. Furthermore, OSSIM can directly utilize images captured using SSIWM without modifying the setup. The proposed method is supported by a series of derivations and is validated through simulations and experiments.

The infrared remote sensing monitoring technology based on the absorption characteristics of gas molecules can detect gas components at long distance, real-time and multi-gas simultaneously.In this paper,we present the method of ethylene gas identification based on infrared absorption characteristics and carry out the field verification experiment of ethylene gas by infrared spectrometer. The effective experimental data are processed and analyzed by differential method and correlation coefficient method. The results indicate that the method can effectively identify the gas with high accuracy, and the research results provide a new technical approach for the effectively identification of gas.

A hybrid fiber grating for refractive index (RI) measurement with temperature compensation is reported and experimentally validated. The sensor is fabricated successively by inscribing long period grating (LPG) and tilted fiber Bragg grating (TFBG) in the same region of an optical fiber in sequence. The measured RI at different temperature agreed well with the standard value. The RI sensitivities is 579.36 nm/RIU.

The docking ring is a typical structure on space targets, and the spatial circle feature extracted from it is an important reference mark for non-cooperative space target vision measurement. However, there are two problems in the pose calculation process: the docking ring pose calculation result of the monocular camera is ambiguous, and the roll angle information cannot be obtained when the pose is solved. In this paper, a non-cooperative space target binocular vision 6- DOF pose measurement method based on docking ring feature is proposed. The binocular vision measurement system is used to solve the ambiguity problem of the docking ring calculation result, and the target coordinate system is constructed by selecting reference feature point outside the docking ring to realize 6-DOF pose measurement. The accuracy and stability of the method are verified by digital simulation experiments, and the results indicate that the method still can calculate stable pose when the pixel position error is 4 pixels. In the scene simulation experiments, the absolute error of vertical optical axis position measurement is less than 1.6 mm, the relative error of parallel optical axis position measurement is less than 0.7%, and the absolute error of attitude measurement is less than 0.2 deg, which can meet the requirements of space navigation mission.

Image fusion is a process of combining complementary information from multiple images of the same scene to generate a composite image. To highlight the thermal target and keep appearance information simultaneously, a target-enhanced fusion method based on YCbCr space is proposed. Firstly, enhancement process is taken in the original infrared image. Three gray images are then obtained via linear computation. Then, color transfer process is accomplished in YCbCr space. Each of the channel' s mean and standard deviation is matched to complete color transfer. Different kinds of reference images are selected to generate different kinds of fusion results. A natural daylight color image is utilized to implement false color fusion, while a reference image with more red components is utilized to implement gray fusion. Besides, parallel acceleration is implemented to improve the practicability of the algorithm. The dynamic memory space allocation problem of Graphics Processing Unit (GPU) is solved by the optimization of multi-dimensional index linearization methods and the algorithm modification for computing statistical parameters. The experiment results of fusion algorithm show that in either mode (color/gray), the proposed method is able to obtain a fused image which pops out enhanced targets, without losing the details of the background. The experiment results of parallel acceleration show that the speedup ratio of an image pair sized around 640×480 is approximately 8, basically realizing real-time process.

MOS resistor arrays are the core devices in infrared hardware-in-the-loop simulation, and the imaging quality is directly related to the accuracy and confidence of the final simulation results. At present, a series of problems, such as image degradation and coupling distortion, will occur when the simulated digital infrared signal enters the MOS resistor array. Therefore, it is necessary to analyze the imaging principles and energy transfer process of the MOS resistor array based on its imaging mechanism, and to establish a process and radiation model of a single pixel, to represent its own physical characteristics. A similarity framework between input and output image signals was constructed, and the relationship between signals was tested and verified by image similarity algorithms and a multi-attribute fusion algorithm. The proposed similarity framework could provide an objective evaluation method to measure the MOS resistor array imaging quality. These achievements could provide an important theoretical basis for future research on coupling characteristics, reverse correction models and non-uniformity correction of larger scale MOS resistor arrays, while having significant value in practical engineering applications.

Tongue diagnosis is an extremely effective and non-invasive auxiliary diagnostic technique. Tongue segmentation is a vital procedure of computer-aided tongue diagnosis system, and its accuracy will directly influence the results of tongue diagnosis. By revising the edge indicator function, in this paper, an improved distance preserving level set evolution (DPLSE) method is proposed for tongue image segmentation. And before segmentation, the grey-level integral projection algorithm, Otus method as well as morphological processing will be utilized to handle tongue images, which to obtain the initial contour curve of this method. The improved algorithm has been experimented on 20 tongue images. Compared with other methods, it shows the competitive performances on tongue images segmentation.

As one of the key steps of phase measuring deflectometry (PMD), surface reconstruction is of great significance to realize high precision surface reconstruction. Considering the actual situation, the sampling points on the surface to be measured are not uniformly distributed. Given this non-uniform meshes distribution, a novel method was presented based on subset interpolation. The innovative method of surface reconstruction is realized by the improved Lagrange polynomials. According to the numerical simulation and analysis, the simulation results show that the proposed reconstruction method is appropriate for the reconstruction of various surfaces in non-uniform meshes. Under the conditions of the simulation, the accuracy of surface reconstruction of the traditional method is in the order of 1×10^-2 mm, while the accuracy of surface reconstruction of the improved method is as high as 1×10^-7 mm.

Fast and accurate on-line monitoring and early warning of toxic, harmful, flammable and explosive gases is an important part of ensuring industrial and agricultural production safety and residents' safety. Photoacoustic spectroscopy (PAS) plays an important role in trace gas sensing. Researchers are focusing on improving the performance of PAS-based gas sensors to satisfy different applications. This paper mainly introduces our recent work on improving the performance of photoacoustic spectroscopy gas detection system.

We proposed a novel multipoint sensing method for large strain measurement combined fiber loop ringdown (FLRD) and frequency-shifted interferometry (FSI). Using this method, a biconical tapered multimode fiber was used as a sensor head for large strain measurement and a serial dual-point strain sensing system was experimentally validated. By measuring the ringdown distance of each FSI-FLRD strain sensor, the strain and position of each sensor can be simultaneously obtained. Using such strain sensors, the strain sensitivities of 0.51337 km^-1·mε^-1 and 0.8667 km^-1·mε^-1 within a large measurement range of up to 6 mε were achieved.

This study proposes an experimental method for the performance evaluation of a commercial combined probing system equipped with a contacting probe, an imaging probe, and a line laser scanner developed by our cooperation. According to its application purpose, this method first obtains the circular characteristics of our novel designed 3D artefact composed of 2D rings, cone and cylinders. It is suitable to measure the touch probe, imaging probe as well as optical sensor. Next, detailed measuring procedures were defined for this artifact, in order to achieve comparable results and make the measurements feasible for the different sensors involved. A series of representative experiments were carried out on a commercial combined probing system produced by our partner. The experimental results show that multiple probing system form error and location error were less than 4.0μm, and multiple probing system size error was less than 2.0μm in three different registration positions. System combination errors were less than its maximum permissible errors (MPEs). On the other hand, its root mean errors (RMSE) were less than 0.5μm. Therefore, we can conclude that the designed artifact is suitable to be used to assess the performance of CMMs with multiple probing systems. These conclusions are helpful for further use of this combined probing system and can be utilized to optimize those combined parameters further.

Retroreflection, which is also known as the cat-eye effect, occurs in many imaging systems. The laser beam that irradiates on the focused photodetector would be reflected along its entranceway, by means of which the focused imaging system could be easily discovered and located. The paper analyzes the present research status of retroreflection reduction techniques. It shows that the related techniques mainly focus on four aspects: defocusing, masking, filtering, and one-way optical device. However, there are still some apparent disadvantages among the above technical schemes, which are generally manifested in the severe loss of imaging quality and the restricted application scope. Along with the rapid development of parallel computing platforms in recent years, computational imaging is widely applied in many fields. The paper proposes two novel configurations of anti-laser reconnaissance imaging systems based on the wavefront coding and the light-field rendering. Applying the computational imaging techniques will hopefully achieve a substantial retroreflection reduction without severely degrading the imaging quality, which shows us a broad prospect.

The laser one-dimensional range profile of a target can be approximated as the convolution of the transmitted laser pulse and the range-resolved laser radar cross section. Therefore, the widening effect caused by the laser pulse is eliminated as much as possible by echo deconvolution, and the resolution of the target laser one-dimensional range profile detection can be improved to some extent. To this end, the Richardson-lucy image iterative deconvolution algorithm is introduced into the laser echo deconvolution. Although the algorithm can eliminate the influence of Poisson noise effectively，In order to further improve the deconvolution effect, wavelet noise reduction is first performed to improve the signal-to-noise ratio of the measured data before using the algorithm. The effectiveness of the proposed algorithm is verified by simulation experiments.

In the aero engine, as one of the most important supporting components, casing has to suffer various loads such as gravity, axial force of gas, inertial force and inertial moment etc transmitted from the turbine rotor and other structural parts, which may lead to the radial geometrical deformation of the casing, especially at the region of the fixture fringe. Also, oversized deformation of the fixture fringe might produce huge hidden dangers to the flight. Therefore, aiming at the measuring assignment of the radial geometrical deformation of the fixture fringe, a non-contact measuring system is set up in the paper, as well as the mathematical model presented in detail. Composed of auxiliary fixing devices, force loading devices and laser displacement sensors etc, the measuring system could be utilized to detect the deformation at every mount on the outer wall of the inspected casing, and then calculate the deformation parameters of the fixture fringe by the mathematical model. As the experiment results shown, through collecting the outputs of the sensors and substituting them into the mathematical model established, the contour features and eccentricity displacement of the fixture fringe after deformation could be derived, which is of certain practicality in the improvement of the whole performance of the aero engine.

Due to advantages of room-temperature and low dark-noise, upconversion is an alternative to state-of-the-art mid-infrared (MIR) detecting technique. The upconversion technique has been applied in a diverse fields such as imaging, analsing spectroscopy and Lidar. A comprehensive theory for upconversion employing collinear quasi phase matching (QPM) is presented. In this work, we present a upconversion model with considering the collinear beams separately focused into periodically poled lithium niobate (PPLN) bulk. Based on the known comprehensive theory of QPM, we build the efficiency function about incident angle by investigating the minimum phase-mismatch of the signal in PPLN. Then we rewrite the upconversion efficiency function according to the pump light field distribution. Finally, by calculating the integral of the efficiency function over the incident angle, the upconversion theoretical model is developed for upconversion process with both beams focused. To check the upconversion theoretical model, we simulate the upconversion efficiency curve about temperature and measure the upconversion efficiency curve of our system with the same temperature range. In our system, the pulse signal at 1550 nm with the peak power 40mW is upconverted to 863 nm with the continuous wave pump laser at continuous-wave 1950 nm with 800mW in a 10 mm long and 1 mm thick PPLN bulk. The experimental results show that the upconversion modeling is agreement with experimental data and it can be used in upconversion imaging.

Environment-2 (HJ-2) satellites will be launched after 2019, which are designed as the successor of Environment-1 (HJ- 1) satellites in Chinese Environment and Disaster Monitoring and Prediction Satellite Constellation. Different from HJ-1 satellites, a new multispectral single-viewing polarimetric instrument called Polarized Scanning Atmospheric Corrector (PSAC) will be onboard on HJ-2 satellites, and further provide the aerosol properties for synchronous atmospheric correction of the main sensors, such as the multispectral charge-coupled device (CCD) cameras onboard the same satellite. In this way, the multispectral surface reflectance could be further obtained from the remote sensing measurements of CCD cameras by the atmospheric correction with the retrieved aerosol properties from PSAC. In this paper, based on the optimal estimation (OE) theory and information content analysis method, we have a preliminary study on the propagation errors from the retrieved aerosol properties to multispectral surface reflectance in the process of synchronous atmospheric correction. The priori information and errors for the analysis are assumed based on the measurement noise of CCD cameras and a priori error of retrieved aerosol optical depth (AOD), as well as typical multispectral reflectance from USGS and ASTER spectral library. For the simulation of synthetic measurements of CCD cameras, Unified Linearized Vector Radiative Transfer Model (UNL-VRTM) has been used as the forward model. By this means, the posterior errors of multispectral surface reflectance are calculated, and the errors propagations can be evaluated theoretically, which can further provide key support for the study of synchronous atmospheric correction in HJ-2 satellites.

In order to suppress occasional jamming signal and to improve the use of the local oscillator power, a differential detection method is proposed in LDV scheme employing two photodetectors, where the main detector receives the Doppler signal while the auxiliary one detects outside jamming signals. The effectiveness of the method is verified through jamming signal rejection experiment. Theoretical analysis and simulation indicate that the SNR of the system is sacrificed to eliminate jamming signal. The differential detection decreases the SNR of the system since the noise yielding in two differential currents are mutually independent and cannot be eliminated. The jamming signal rejection experiment shows that the differential detection is capable to reduce nearly 90% of the amplitude of the occasional jamming signal, thus improving the measurement accuracy of the Doppler frequency and further improving the velocity measurement precision.

Scanning white light interferometry (SWLI) has become an established method to measure the geometrical form of objects. However, due to its complicated condition on the fracture surface, the noises severely degrade its interference signal quantity, consequently cause large reconstruction error. To improve the reconstruction accuracy, this paper proposes a method which adopts the Monte Carlo algorithm to simulate the interference data of a fracture surface. In our method, a random Gaussian surface is first generated as the fracture surface in the following experiments. Then, a numerical model of white light interference is constructed and thereby interference images based on Gaussian surfaces are simulated by the use of Monte Carlo method. In the experiments, the influence of surface parameters and repeated times of calculation on the results of simulation is observed and the process of longitudinal equi-distance step scanning in interference detection is simulated. The experimental results show that when the repeated times is large enough, the characteristics on the interference image becomes obvious. By observing the longitudinal interference signal, the interference curve shows similar properties to a interferogram signal. Finally, we analyze the theoretical feasibility of a parallel integral filter for the experimentally measured interference data. The results prove that the simulated interference data possesses primary capability in restoring surface information.

Panoramic imaging technology based on area array infrared uses area array staring infrared FPA, instead of linear infrared FPA. By utilizing FOV expanding instead of 360° scanning image, it can effectively decrease the system size and weight, and improve the range performance and reaction time. Currently, area array infrared panoramic imaging technology has become the hot topic and development direction of infrared imaging system. Based on deep research and analysis in area array infrared panoramic contra-scanning imaging technology, the contra-scanning imaging theory was ratiocinated, and the image rotation correction technology also was simply expatiated .In the end, this paper present the experimentation result and analysis. Thank to the Breakthrough of these key technology, it provides technical support for the renovation of panoramic imaging system from linear infrared sensors to area array staring infrared sensors.

Tongue diagnosis is an important part of the Traditional Chinese Medicine (TCM) diagnosis. In Chinese Medicine, tongue body reflects the most sensitive indicators of the physiological function and pathological changes, which has important application value in the process of diagnosis and treatment of the TCM diagnosis. The accurate separation of tongue body from tongue image is the premise of recognition and diagnosis. Most of the proposed tongue segmentation algorithms are based on the improvement of traditional approaches. These algorithms can improve the segmentation accuracy of tongue image to some extent, but they are less robust. To address above problems, a method of fast tongue image segmentation algorithm using convolutional neural network is proposed in this paper. The network is inspired from ShuffleNet which provided an efficient classification and detection network. The running time of our structure is about 0.16s, and the average segmentation precision is about 90.5%, which makes it of great potential for real-time applications. As opposed to the two common traditional segmentation methods (Kmeans++, GrabCut), the proposed method performs better than the above algorithms.

Optical vortex is a kind of unique structure light with a helical phase distribution and contains orbital angular momentum. It has been found a myriad of important applications of optical vortex, such as micromanipulation, remote sensing and communication. In recent years, there are many researches on the particle manipulation based on the orbital angular momentum of optical vortex. Especially, there is a new kind of optical vortex which is so-called “perfect” vortex whose ring radius is independent of its topological charge has an outstanding performance on the micromanipulation. However, the exist experiments can only realize manipulation of particle and the rotation speed is difficult to obtain. In this paper, we proposed a new scheme which can manipulate the particle and simultaneously detect its rotation speed. We employ the superposition perfect vortex as the probe beam. It is worth to note that the topological charge of the perfect vortex we used has an opposite sign and different magnitude. Therefore, the probe beam possesses remaining orbital angular momentum and can generate the rotational Doppler effect. The rotational Doppler effect is the basics of rotation speed detection. A corresponding experiment has been conducted to verify our method. The results have confirmed the existence of orbital angular momentum of superposition optical vortex with different topological charge. Our scheme can realize manipulation and detection the rotation speed of the particle simultaneously. It is an important supplement on the micromanipulation and maybe useful in the optical gyroscope technique.

In automatic camera calibration with traditional chessboard patterns, the corner sorting results are usually influenced by the rotation angle of the calibration pattern. Therefore, this paper designs an improved chessboard pattern and corresponding corner extraction algorithm. In the new pattern, five nested rings are added near the four corners to determine the sorting origin.After completing the checkerboard positioning process, the improved algorithm first identifies the nested contours by five concentric circles on the four corners of the calibration plate. Then it identifies the center of each contour and determines the order of four centers. After that it uses a perspective projection to correct part of the image on the calibration plate and reorder the calibration points in order to obtain a sequence of calibration points. Experiment results show that the corner detection results are correct and the new method has a lower mean reprojection error per image.

Surface defect detection of optical components is commonly used in the fabrication of high quality optical components. The presence of defects reduces the local damage threshold of the component. When the laser energy is higher than the threshold, it will cause damage due to absorption of too much energy. Somethings it even causes cracking of the entire component. Therefore, the quality inspection of optical components and the formation of accurate quality assessment are technologies in the production and processing of high quality optical components. The data discussed in this paper all come from dark-field scatter imaging, which is a commonly used detection method. In dark field imaging, surface defects of the optical component will produce scattered light under the illumination of the light source, which is captured by the detector and reflected on the captured image. However, some scratches with a narrow width and insufficient depth are difficult to generate enough scattered light, which is usually caused by uneven force during polishing and grinding. It is an extremely weak straight line when reflected on the image. Because of the limited brightness, it is difficult to capture by the human eye or ordinary method of machine vision. The primary cause of weak scratches is that the signal intensity exhibited in the image is extremely low. Weak scratches’ gray value is usually only slightly higher than normal noise, and some are even submerged in noise, which leads to difficulties in identification. The enhancement algorithm proposed in this paper avoids the low gray value of weak scratches in the spatial domain, and successfully finds its characteristic with obvious discrimination, that is, its frequency domain characteristics. The pixels of weak scratches are usually connected stably and smoothly in a specific direction to form a straight line, which is their extremely continuous spatial continuity, although they are low in intensity. Through Fourier transform, the spatial continuity of weak scratches in a certain direction can be integrated, and the signal appearing in the vertical direction of the frequency domain is similar to strong scratches. Both of them show a very clear distinction. In contrast, other elements in the image, such as dust and pitting, are basically in the form of a circular shape, which is uniform in all directions and is submerged in the frequency domain by Fourier transform. In addition to scratches, dust, and pitting, there is another element that cannot be ignored in the detected image, which is noise. It usually includes the noise of the sensor itself, the noise caused by the light source and so on. Due to the uncertainty of the noise, the frequency distribution is also unpredictable and will also interfere with the final test results. In this paper, the inverse filtering method is adopted. The scratch information with discrimination is removed in the frequency domain, and the image after inverse transformation contains almost all noise, dust and pitting. After the difference with the original image and result, a pure scratch image was obtained at the expense of the vast majority of image. Since there is basically no noise interference, the detection threshold of the Hough line detection can be directly reduced, and the weak scratch can be easily captured. Without above work, a large amount of noise will lead to failure of scratch detection.

Based on the Mie scattering theory, the spectral radiance of missile plume is calculated with the alumina particles model at the visible waveband of 400nm~800nm. The software Modtran is used to simulate atmospheric transmission characteristics and atmospheric background radiation, obtain the transmittance of visible signals at different heights in the vertical direction of the atmosphere and the atmospheric background radiance of visible wavebands under different conditions. By analyzing the radiation transmission process, the radiation reception model of the detector was established to calculate the ratio of the number of electrons between the target signal and the atmospheric background noise at different heights. Then, based on the relevant parameters of the detector, the relationship between the signal-to-noise ratio (SNR) and the height and wavelength was calculated to evaluate the visible detection capability of the detector to the missile plume. It is analyzed that when the target height is greater than 10 km, the SNR in the same band tends to be constant and meets the detection requirements .Therefore, the visible sensor can theoretically be used to build imaging system for detecting the plume signal in the daytime.

Titanium dioxide (TiO₂) thin films were grown on SiO2 substrates by DC magnetron sputtering combine with thermal oxidation. A series O₂:Ar ratio from 0:50 to 25:25 and a set of post thermal oxidation at 380~550 oC were tested respectively. The transmittance of titanium dioxide thin films changed with the sputtering parameters and thermal oxidation process in the range. The experiment results showed that reactive gas concentration, sputtering power, sputtering time, film thickness, oxidation temperature and oxidation time had great influence on optical properties of the titanium dioxide thin films. Finally a typical O2:Ar ratio of 20:30~25:25 and a sputtering time of 5 min were selected as the optimized experimental conditions. The optical parameters include: ultraviolet absorption, visible transmittance and the absorption band gaps of the titanium dioxide samples are about 100%, 85% and 4.15 eV.

In order to satisfy application requirements of space borne imaging loads development and space target detection technology research, an approach by using space target optical characteristic models and sensor imaging characteristic models to generate original frame images, and using the system complex MTF calculation method to transform original frame images into simulation images is proposed. Additional, the 3D scene generation and driving technology are used to simulate the optical characteristics of space targets in different positions and attitudes during the process of frame image generation. In this approach, imaging factors include space environment, detection system and operation state are taken into consideration, and the target optical characteristics are reproduced realistically, the static or dynamic simulation of detection equipment, simulation verification of target recognition and tracking technology are supported. Simulation results show that this method can reflect characteristics of orientation, attitude and material, signal-to-noise ratio, dynamic range, detection angle, illumination angle and other state on target imaging. Which can satisfy the requirements of ground simulation and provide reference for the research of space target imaging technology.

To obtain high accuracy polarization observation information is highly expecting in aerosol parameter retrieval and atmosphere environment research. In this paper, we described a space-borne multispectral polarized scanning atmospheric corrector (PSAC), which can provide extremely high polarimetric accuracy. And we use wavelet-based denoising method to improve the stability of PSAC measurement results by reducing internal noise. The result shows that the STD of DOLP difference between PSAC measurement value and theoretical value is significantly reduced, reached 5%~10% in the requirement DOLP difference accuracy 0.5%, the proposed threshold function can increase the evaluation accuracy stability of instrument polarization and reduce the uncertainty, also, the measurement results of PSAC inflight improved as well.

In the traditional pose detection method, the interferometer based on laser interferometry is bulky and expensive, and requires strict environmental temperature. The direct optical triangulation is limited by the aperture of the imaging lens, resulting in loss of light energy and reducing detection resolution. The oblique triangulation has serious shading phenomenon when detecting surface objects or complex surface targets, and the application range is narrow. The optical autocollimating method is applied to the field of small angles detection, but has the disadvantages of large size, low precision and complex structure. Therefore, it is of great scientific value to improve the accuracy of the pose detection system and reduce the volume of the detection system. In response to the above requirements, this paper designs an improved optical autocollimating detection system based on dual two-dimensional PSDs, which improves the accuracy and reduces the volume of the detection system. The position and angular resolution of the detection system is up to μm and μrad.

We developed the scintillation model of non-uniformly sinc-correlated blue-green (NUSCBG) laser beam in oceanic turbulence based on the cross-spectral density. The scintillation index and intensity are numerically simulated when propagation distances are varied. It is shown that the oceanic turbulence will affect the intensity and scintillation index of non-uniformly sinc-correlated blue-green laser beam. The non-uniformly sinc-correlated blue-green laser beam has a lower scintillation and higher propagation intensity than Gaussian-Schell model (GSM) beam at a certain distances in oceanic turbulence.

To enhance the performance of Fourier single-pixel imaging using lower data, we propose a non-uniform spectrum sampling for FSI instead of the traditional uniform spectrum sampling. The principle is deduced, and the corresponding simulations are conducted to verify and evaluate the performance of our strategy. Results show that non-uniform spectrum sampling for FSI is feasible. Meanwhile, compared with the traditional spectrum acquisition strategy, our strategy shows an advantage in measurement efficiency and high reconstruction image quality under the same sampling ratio. Our proposed strategy has a good application prospect in video acquisition, multispectral hyperspectral imaging or other high speed and high precision field.

The characteristics of turbidity in the watershed of Chongqing City’s water supply system in interconnected reservoir basins between JiaLingJiang River and Chang Jiang River are investigated and analyzed by dynamic light scattering method (DLS). Three months of continuous turbidity measurements in seven sampling sites along the JiaLingJiang River were respectively performed from March to May in 2018. The experiment results demonstrated that the particles with highly similar light-scattering features are the main contribution to turbidity in the JiaLingJiang River. The analysis of turbidity time series showed that the particle populations from water sources impacts in downstream waters and the influence of urban wastewater pollution and wet weather pollutant was not obvious in those months. On the other hand, the relative errors of turbidity measurement results were always less than 3% with national turbidity standard.

At present, Discriminative Correlation Filter(DCF) based trackers and Deep Learning based trackers are the main methods to achieve visual tracking. Although they have achieved promising performance in many cases, there are still some inherent flaws that they can't overcome. Neither of the two main tracking algorithms can achieve satisfactory tracking performance, and considering that they can complement each other to some extent. In this paper, we focus on combining them together for a better tracking. To this end, we select several Correlation Filter and Deep Learning based tracking methods, then modify them appropriately and take different combinations to get a comprehensive result. To meet the real-time requirements, in the DCF branch, we mainly use hand-crafted features rather than deep features. Finally, we propose a new adaptive fusion approach to improve the tracking robustness and accuracy. Comprehensive experiments are performed on several benchmark datasets, using the evaluation criteria which have been proposed by the corresponding benchmarks. In order to fully understand the role of each branch and the effect of fusion strategy, our approach is compared with corresponding individual branches meanwhile the combination of our branches is compared with different fusion strategies. Finally, our approach is compared with state-of-the-art trackers, and the results show that our method has good accuracy and robustness when compared with other methods.

In this paper, a two-dimensional (2D) laser radar system is designed. The working principle of pulsed two-dimensional laser radar is introduced. The driving circuit of laser emitting system is designed and simulated. The suitable parameters are acquired. Afterwards, the ranging result is calculated by the TDC-GP22, and the azimuth angle is acquired based on the encoder. The experiments are carried out, and the echo signals are measured at different distances. It provides the basis for unmanned aerial vehicle technology.

Three-dimensional contour imaging is used to reconstruct the surface of complex contour. Line-structured light is characterized by fast measurement, large amount of data and nondestructive to contour surface and is widely used in 3-D imaging. Therefore, a series of calibration methods for line-structured light are also produced, such as cross-ratio invariance, triangulation method, polynomial and so on. However, the traditional calibration methods are complex and take a long time, so a simplified method is proposed. This method omits the complicated process of calculating the cross-ratio and obtains the equation of light plane by accurately calculating the external parameters between the target and the camera and get the 3-D points of the line-structured light by the pinhole camera model. What’s more, RANSAC is applied to get the more precious line-structured light plane by eliminating the wrong points. Moreover, errors are measured and analyzed during the process of structure light calibration.

The uncooled thermal infrared imaging spectrometer has advantages of small size, low cost and so on, can monitor high temperature events in the extreme thermal environment. However，the difficulties in detecting objects with low signal energy, serious thermal infrared background radiation and other problems limit its development and application. Restraining self-radiation stray light is the key to successfully overcome these difficulties. A long-wave infrared imaging spectrometer is designed in this paper, with 7 to 14μm wavelength range and F number of 2.7. By establishing its optomechamical model, two-step method of suppressing self-radiation are studied. The first step is using a mechanical structure with a gold film. Its reflectance is more than 98% in the thermal infrared band, thereby lowering the emissivity of the lens surface. Compared to the blackened mechanical parts, the polished one can reduce the self-radiation by one order of magnitude. However, it is still two orders of magnitude higher than the irradiance of the 500K target, and the spectral image signal is submerged. The next measure is to add a shutter device at the spectrometer entrance slit, so that signals reaching on the image plane when the shutter is opened and closed can be detected consequently. The effective spectral image signal is extracted by the background noise removal algorithm. The measures effectively solve the problem that the self-radiation stray light affects the imaging quality of the uncooled thermal infrared imaging spectrometer.

The artificial circular targets are used commonly in optical measurements including camera calibration and 3D object reconstruction. In the present study, the researchers usually depend on experience and intuition to manually determine the size of the circular targets, which is found to be important to the accuracy and efficiency of image position measurement. A larger target size may lead to a larger eccentricity error of the center of a circular target, while a smaller target is disadvantageous for image processing. Therefore, a suitable target size is required to guarantee a reliable image point measurement. In this paper, the problem of circular target size selection is investigated. Firstly, a theoretical model about the perspective imaging of a circular target is obtained. This mathematical model further leads to a novel and practical method for selecting a proper size of circular targets. Finally, experiments using circular coded targets are performed to validate the correctness and effectiveness of the proposed method. The experimental results indicate that the measured semi-major axis of the image ellipse corresponding to the circular target agrees well with its theoretical design value, and the existing differences are mostly within the tolerable range of the measurement error, as the maximum difference is estimated to be about 0.5pixel. Without any calibration parameters and high-cost equipment, this method shows significant potentials in various optical measurements.

Micro-channel plate is an electronic multiplier element with two-dimensional hollow glass tube array structure, which has been widely used in low-light-level night vision imaging, particle detection and other devices. Bulk resistance of microchannel plate is an important performance index, which affects the electronic multiplication performance, dynamic response range and time resolution of micro-channel plate. There are many literatures about the influence of the preparation process of microchannel plate on bulk resistance, but few reports about the influence of the working conditions of microchannel plate on bulk resistance. In this paper, we mainly study the influence of micro-channel plate voltage and ambient temperature on bulk resistance, and analyze the mechanism of the change by tunneling. The results show that: 1) The change of working conditions leads to the change of the bulk resistance of the micro-channel plate. The higher the temperature and the voltage of the micro-channel plate, the lower the bulk resistance of micro-channel plate. The larger the original bulk resistance, the smaller the change rate of the micro-channel plate is. 2) The phenomenon that the resistance of micro-channel plate varies with the use conditions conforms to the mechanism of tunneling conduction.

Compared with the traditional single-channel multi-spectral remote sensing camera, the multi-spectral remote sensing camera with dual-channel imaging can capture more spectral information of spectral segments. In order to make the dual-channel multi-spectral remote sensing camera image well in various complex mechanical environments, the structural dynamic analysis of the camera was carried out. First, the optical system and structural composition of the two-channel camera are introduced. After that, using the Patran finite element analysis software, based on the establishment of the finite element model, the modal analysis, overload adaptability analysis and random vibration analysis of the camera were carried out. According to the analysis results, a damping isolator is added to each mounting foot of the camera, which effectively reduces the random vibration response of the camera's key measuring points. Finally, the mechanical environment test of the camera is carried out. The results of finite element analysis and test are in good agreement, which verifies the correctness of the analysis and calculation results. It shows that the dynamic performance of the dual-channel multi-spectral remote sensing camera with the outer envelope size of 1500×1500×1000mm meets the design requirements.

In order to improve the detection capability of foreign objects debris (FOD) on airport runway. A wide area, high resolution infrared polarimetric surveillance system has been designed. Infrared polarimetric imaging can increase the dimension of the detection information ,then improve the detail features and contrast of the FOD image, the range of surveillanc is expanded by optical multiplexing while the image resolution remains unchanged. The focal length of the optical system is 80mm, the F number is 2, the pixel resolution is 1.29′,the frame rate is 10Hz, the MTF is higher than 0.8 at the 17lp/mm. The experimental results of the FOD detection indicate that the field of view of this system has reached 20.62°×5.5°, the horizontal field of view was nearly 3 times than the optical system with the same focal length, comparing with the intensity image，the contrast of target and background is enhanced by 41.6 to 207.9 times, the local signal-to-clutter ratio is enhanced by 1.1 to 2.2 times.

We report in this paper a miniature adjustable-focus camera module integrated with a solid tunable lens driven by MEMS-thermal actuators. Thanks to the compact structures of the MEMS actuators and the optical-power-variation capability of such solid tunable lenses, such a camera module shows great potential in various applications, especially in tiny underwater imaging systems where an optical zoom or focus-tuning function is required. The camera module presented in this paper consists of a solid tunable lens for optical power tuning, two identical MEMS-thermal actuators for lens component driving and one commercial CMOS chip for image recording, assisted with necessary mechanical parts for supporting and housing. We first introduce the optimal design of the solid tunable lens which consists of two freeform components moving in the direction perpendicular to the optical axis, and subsequently, the MEMS thermal actuators which consist of V-shaped micro beams. The lens components are fabricated by the technique of single-point diamond turning followed by the PMDS modelling process while the MEMS-thermal actuators are materialized by a commercial MUMPS process. The static performance of the designed system, including the temperature distribution, displacement-versus-voltage curve and the optical tuning capability, is characterized in detail, together with the dynamic responding speed, hysteresis and imaging performance stability during tuning. Results show that a maximum output displacement of 135 μm is achieved by the optimized MEMS-thermal actuator with a driving voltage of 10V, and consequently a focal length tuning range from 9.2 to 7.9 mm with a responding speed of about 90 ms is realized by the solid tunable lens. The highest temperate on the actuator is about 690 K during the operation while the temperate increase on the lens components is found to be about 30 K, which guarantees the optical performance stability. Targets placed at different object distances are clearly focused by the assembled miniature camera module with various driving voltages, which demonstrate its adjustable focus capability. Such miniature adjustable-focus camera modules show promising future in underwater applications due to their compact structures and optical-power-variation capability.

In this paper, a three-dimensional (3D) shape measurement method based on structured light field imaging is proposed. Generally, light field imaging is challenging to accomplish the 3D shape measurement accurately, as the slope estimation method based on radiance consistency is inaccurate. Taking into account the special modulation of structured light field, the phase information is derived with Fourier transform profilometry, which is utilized to substitute the phase consistency for the radiance consistency in epipolar image (EPI) at first. Therefore, the 3D coordinates are derived after light field calibration, but the results are coarse due to slope estimation error and need to be corrected. Furthermore, the 3D coordinates refinement is performed based on relationship between the structured light field image and DMD image of the projector, which allows to improve the performance of the 3D shape measurement. The necessary light field camera calibration is described to generalize its application. Subsequently, the effectiveness of the proposed method is demonstrated with a sculpture and compared to the results of a conventional PMP system.

As a key component of next-generation photovoltaic technology, quantum well solar cells (QWSCs) have received great attention in the past few years. The growth characteristics and structure of III/V materials also provide a new choice for QWSCs. In this paper, a novel multi-quantum well solar cell is proposed, in which InGaAs/InGaAsP quantum wells (QWs) are inserted in the intrinsic region of the PIN structure, and the thickness, number and position of the QWs are optimized. Compared with ordinary solar cells, the short-circuit current (J_sc ) increased from 30.25mA/cm² to 42.65mA/cm², and the cell efficiency increased to 27.4%. Then, after adding an anti-reflection layer (ARC) on top of the QWSCs, J_sc has increased another 7mA/cm² on average on the basis of previous one. It is clear that InGaAs/InGaAsP QWSCs absorb more incident sunlight. Furthermore, the influence on J_sc of the different position of QWs in the intrinsic region is also discussed. The results show that placing the QWs on top of the intrinsic region maximizes the efficiency of the solar cell.

The paper presents a method based on the principle of auto-collimating to assemble the large-aperture laser beam reduction system. The method solves the problem of using fiber laser, plane mirror and Hartman wavefront sensor to realize the precision assembling of the large-aperture laser beam reduction system in the absence of large-diameter standard light source. Using the method, The large-aperture laser beam reduction system is successfully assembled in the big science project. And the technical index of the system is tested and the uncertainty is analyzed. The near field modulation degree is 1.03, the contrast is 0.025, the wavefront distortion is 0.476λ(λ=1053nm), and the system meets the requirements of the engineering index.

Aiming at improving spatial resolution and dynamic range of video for real-world applications, this paper focuses on the joint super-resolution, high dynamic range image reconstruction algorithm for multiple images captured by single camera. On the assumption that the response function is same at each pixel with different exposures, the joint super resolution and high dynamic range technology can be implemented. We propose a joint super-resolution and high dynamic range imaging algorithm reconstructed from multi-exposure images simultaneously. We conduct experiments under static and dynamic scene to validate the robustness of the proposed approach. Subjective and objective assessments for various experiments are presented to validate the effectiveness of the proposed super-resolution and high dynamic range reconstruction algorithm.

The whispering-gallery-mode(WGM) resonators have a number of advantages, including ultra-high quality factor(Q factor), extremely small mode volume and so on. It has been widely used in many fields related to high sensitivity sensing measurement, photonics material, linear and non-linear optics, and optical communication. Here we built an experimental platform for microrod resonator fabrication with a high power CO2 laser. Based on this experimental fabrication platform, a microrod resonator with an approximate 2.5mm diameter has been made, which has an ultra-smooth surface. We also designed a test platform used a tapered fiber to measure optical performances of the fabricated microrod resonator. With this test platform, we measured the maximum Q factor of the fabricated resonator, which can reach 1.52×10⁸ under the condition of 1550nm wavelength. The fabrication platform for microrod resonator designed by our laboratory with features of fast (less than 10min), cheap, repeatable and low experimental condition. These features have huge advantages on further scaled sensing application, optoelectronic device. Furthermore, in order to design and fabricate the ultra-high sensitivity temperature sensing device, we demonstrated the frequency shift feature of the fabricated microrod resonator. We heated the microrod resonator from 22 ^oC to 25 ^oC , then calculated the experimental data. we demonstrated our microrod resonator has 0.04nm frequency shift, 14.41pm/^oC temperature sensitivity, and 6.3♦10^{−3 o}C temperature resolution.

Image enhancement is a critical processing step for various vision-based applications, and many nonlinear methods are proposed. However, most of them are global techniques, lacking contrast enhancement to bring out fine features and details. Furthermore, they do not work well in various lighting conditions. In order to handle these limitations, an adaptive image enhancement method (AIELN) is proposed based on local luminance statistics and nonlinear functions. The method is composed of three steps: adaptive dynamic range adjustment, adaptive contrast enhancement and color restoration. Dynamic range adjustment is achieved by a series of nonlinear functions with different curvatures designed based on the human vision system, which can adaptively increase the intensity around dark regions and decrease the intensity around bright regions. Contrast enhancement is accomplished by enhancing the intensity of image according to the luminance of the local regions. Finally, the enhanced image is obtained by color restoration in YUV space. Experimental results demonstrate that the proposed method can be effectively improve the quality of the images captured in non-uniform lighting conditions, achieving better balance between dynamic range adjustment and contrast enhancement. Furthermore, the proposed method outperforms several existing methods in terms of quality and efficiency.

High dynamic range (HDR) imaging is an area of increasing importance, but most display devices still have limited dynamic range(LDR). Dynamic range represents the ability of the imaging system to restore the real scene. With the continuous development of imaging systems toward high sensitivity, a higher dynamic range imaging system is more and more demanded. Aiming at the dynamic range expansion problem of the cooled infrared imaging system, this paper proposed a super-framing algorithm to enlarge image dynamic range. Specifically, a model for automatically selecting the integration settings of such images is presented based on the camera characteristic function. It is used to calculate the optimal integration time of different temperature targets in the scene. Afterwards, fuse these frames into an image which possesses all well-exposed areas and give a sense of capturing a high dynamic range scene. Experimental results demonstrate that the system dynamic range can effectively improve 10dB when fusing three frame images. the system dynamic range is from 70dB up to 80dB, the temperature range is from 20°C up to 370°C. The strength of the proposed method lies in its ability to avoid high computational cost using traditional irradiance method applied in the infrared imaging field. Its great performance is conductive to human observation with good imaging effect, low computational complexity and engineering feasibility. The method can be applied to engine test, explosion flame and other high dynamic scenes with high temperature targets.

When a feature point detection method is used in vision SLAM to match images, environment condition around the robot is uncertain usually. Many influence factors such as rotation, scale, fuzzy as well as illumination in the process of detection have a strong impact on robot's locating and incremental map building. Experiments proved that SIFT, SURF, BRISK, ORB and FREAK have good robustness under normal illumination. However, the illumination is complex in practical applications, and the stability of image features extraction will be affected. Based on a mobile robot vision platform, the speed, repetition rate and matching rate of five feature extraction algorithms above are compared and analyzed with different methods. Under dynamic illumination, the robustness and matching effect of image features with translation, rotation, scale and fuzzy transformations are also compared. Through experimental data analyzing, BRISK features shows better effect under dynamic illumination.

The dual-probe time-resolved shadowgraphic microscopy system can observe the particle ejection phenomenon during laser-induced fused silica component damage, and the system can acquire two consecutive images with adjustable time intervals within one damage event. The paper presents a method for measuring speed and size automatically of the ejected particles utilizing the two consecutive images. The core work of automatic measurement method is particle detection and pairing by means of hierarchical pairing method, and estimates the instantaneous speed and size of the ejected particles. In hierarchical pairing method, the ideas of unimodal threshold segmentation, adaptive area thresholds and adaptive displacement thresholds are designed and applied. Experiments performed on experimental image pairs showed that the method is helpful to explore the kinetic properties of ejected particles.

In view of the practical demand of infrared (IR) / millimeter wave (MMW) composite interference smoke technology, the extinction mechanism of chopped carbon fiber (CF) to IR and MMW was analyzed, and the chopped CF smoke cloud was formed by explosive dispersion. Taking attenuation rate and effective time as indexes, the IR/MMW composite interference performance was studied experimentally. The results show that the chopped CF has the ability to attenuate IR/MMW, the attenuation is the result of both absorption and scattering, and the smoke cloud of chopped CF has good attenuation effect on IR, 3mm and 8mm waves. The attenuation rate is more than 95%, and the effective time is 45s, 67s and 54s, respectively, indicating that chopped CF is a good smoke material with IR/MMW interference function.

Spectral image information provided by multi-spectral infrared remote sensing cameras has high application value. The registration of multi-spectral infrared camera is a key to improve the efficiency of satellite image acquisition. In order to break through the limitation of high precision of spectral segments imaging devices, a coordinate measuring and dual-path centering technology were proposed.

Research of starlight-level wide-spectrum full-color imaging technology is aimed at the current demand of obtaining the real color image in the low ambient light. because traditional visible light imaging, laser imaging, thermal imaging and other technical methods can only obtain the target grayscale imaging information, but not obtain the target true color information. According to statistics, color images contain 30 times more information than grayscale images, and spectral information is extremely critical in target recognition. This paper intends to adopt an imaging method that integrates super large pixels, ultra-thin process microlens collection, and large-diameter light transmission to increase the sensitivity of the device by 50~100 times. The technical difficulty at this stage is based on large pixel, large area array, high pass light rate, low noise imaging device preparation technology. The key to achieving full-color imaging is the fabrication of large-pixel, large-area imaging devices and high-transmission, low-noise process technology. On this basis, we also designed deep learning image processing algorithms, conducted color brightening and enhancement of devices’ physical true color, and increased the signal-to-background ratio of images, which laid a technological foundation for the follow-up target detection and identification, and industrialized application. lastly, the minimum illumination of color night vision is 0.0001Lux@25Hz, F1.0, thereby achieving wide-spectrum full-color imaging.

According to the requirement of a wide-viewing-angle retroreflector (WVAR) that the max divergence angle cannot exceed 9 mrad, we have made an optimal design of WVAR with radius of 30 mm (n=1.95375@ wavelength of 632.8 nm) to be used to be the reference light in polarization interferometry. Therefore, it is particularly important to calculate its polarization properties accurately. We have applied the three-dimensional (3D) coherency polarization calculus to analyze the designed WVAR, and the theoretical results are in agreement with the simulation results by the FRED software. Finally, it can be concluded that the designed WVAR has a very good ability of polarization-maintaining.

Phase-measuring deflectometry (PMD)-based methods have been widely used in the measurement of the threedimensional (3D) shape of specular objects, and the existing PMD methods utilize visible light. However, specular surfaces are sensitive to ambient light. As a result, the reconstructed 3D shape results are mostly affected by the external environment in actual measurements. To overcome this problem, a novel infrared-PMD (IR-PMD) method is proposed to measure specular objects by directly establishing the relationship between the absolute phase and depth data. In addition, a new calibration method for the measurement system has been proposed by combining fringe projection and fringe reflection. The proposed IR-PMD method uses an IR projector to project sinusoidal fringe patterns onto a ground glass, which can be regarded as an IR digital screen. The IR fringe patterns are reflected by the measured specular surfaces and the deformed fringe patterns captured by an IR camera. The multiple-step phase-shifting algorithm and the optimum three-fringe number selection method are applied to the deformed fringe patterns to obtain the wrapped and unwrapped phase data, respectively. Then 3D shape data can be directly calculated by the unwrapped phase data on the screen located at two positions. The results have validated the effectiveness and accuracy of the proposed method. It can be used to measure specular components in the application fields of advanced manufacturing, automobile industry, and aerospace industry.

The traditional spatial domain sharpness evaluation functions usually have a larger amount of calculation, and the calculation time is relatively longer. Besides, its anti-noise ability is weak, and it is easy to be disturbed by the background factors in the image. The above problems will have an impact on the real-time, sensitivity and reliability of the auto-focus system. In order to overcome these shortcomings, an improved SML sharpness evaluation function combined with threshold is proposed in this paper. This algorithm improve the SML function firstly, and make full use of the edge information of the image. Then a threshold is introduced to distinguish the edge points from non-edge points. So it can not only highlight the edge information while restraining the noise and the flat area in the background of the image, but also can reduce the calculation amount of the evaluation function and improve the real-time performance of the auto-focusing system. Finally verifies the effect of the improved evaluation function based on the simulation experiments. The results show that the algorithm proposed in this paper has better sensitivity and anti-noise ability, and can evaluate the sharpness of defocused images accurately and steadily.

Microchannel-plate-based x-ray optics is designed based on the principle that the lobster eye reflects rather than refracts the object. In practice, the inner wall of the square channel is not absolutely smooth but a bit rough, which causes diffuse scattering of X-rays, resulting in an exponential decline in reflectivity. In the present work, we investigated the morphology of channel inner wall in the etching process and the diffusion depth of the elements at the interface between channel and wall. The diffusion layer is a network-like structure, with the thickness of more than 1μm. As the acid-etching continues, the elements of the channel material in the network are gradually dissolved, and the remaining channel wall materials become the skeleton. After a long time of etching, the inner wall surface is columnar and the roughness is gradually increased. This study provides some guidelines for the preparation of ultra-smooth reflective surfaces.

Infrared (IR) small target detection in complex background is one of the key techniques in many defense systems. In this paper, a novel method based on infrared patch-tensor model with structured sparse regularization (IPTSS) is proposed for small IR target detection. To overcome the structured edge interferences , the IPTSS model adds an edge structured sparse item utilizing the ℓ_1,1,2 norm minimization constraint to the IPT model based on partial sum of tensor nuclear norm (PSTNN). An efficient optimization algorithm based on alternating direction method of multipliers (ADMM) is designed to solve the proposed IPTSS model. After the target-background-edge components are separated, the target image can be reconstructed. Finally, small targets can be extracted easily via adaptive threshold segmentation in the reconstructed target image. Extensive experimental results demonstrate that the proposed method can effectively enhance small IR targets while suppressing the complex background in various scenes.

Angle measurement is the basic problem of mechanical testing theory and technology. High-precision angle measuring sensor is the core component that is irreplaceable for scientific research, advanced manufacturing and test measurement. In this paper, for the long-term technical problems of difficult to suppress the shaft axis error of the circular grating angle measuring sensor, the size and precision are difficult to reconcile, a new concept of multi-grating angle measuring sensor is proposed, and the error of the sensor itself, installation error, electronic subdivision error, and multi-grating measurement are studied. The angle sensor suppresses the shafting error and establishes a simulation model. A multi-grating angle measuring sensor experimental system was built. The experimental results show that the angle error of the multi-grating angle measuring sensor is 134.32"". The proposal of multi-grating angle measuring sensor provides a new way for mechanical angle measurement theory and method.

For the new satellite autonomous navigation technology using sensors with functions of a star sensor and an ultraviolet earth sensor, it lacks the device to simulate target characteristics of stars and the earth. In the paper, we proposed a combined simulation device composed with a visible light star simulator and an ultraviolet light earth simulator. At first, the general optical system designing program of simulators was presented after analysis of working requirements. Then, the designing process of optical systems was described in detail. After that, high precision and profile simulation method was analyzed intensively. Furthermore, an accurate correction method for the angular travel error between two stars and earth flare angle error was lay out. At last, the visible light stars and ultraviolet light earth combined simulation device was utilized. The results show that the precision of combined simulation device which can simulate star positions and earth graphics is high. Moreover, the angular travel error between two stars is less than ±7 second of arc. In addition, earth flare angle error is less than ±0.05°. The results meet the function and precision requirements for autonomous navigation of an attitude sensor on satellite. The high precision combined simulation device may meet the basic requirements for ground precision calibration and functional test of an attitude sensor.

A practical technique, known as Confocal laser endoscopy with the ability of super high magnification and sensitivity, uses a pinhole to reduce the stray light from the samples before and after the focal plane, leading to greatly improve the signal-to-noise ratio (SNR) and axial resolution. The algorithm and the computational efficiency of the image acquisition system as one of the key modules of confocal laser endoscopy significantly influence the imaging quality and timeliness of endoscopy. Therefore, it is necessary to design an image acquisition system with good image quality, fast image refreshing and user-friendly interface to improve the use effect of confocal laser endoscopy and the working efficiency for the doctors. In this paper, a high-frame-rate data acquisition system is designed for the scanning and imaging process of confocal laser endoscopy. By using hybrid programming between C# and C++, the acquisition system able to effectively utilize the computational efficiency of C++ language and the flexible graphical interface support of C# language. The WPF framework is used to realize image display and translation scaling, which can help operators to observe samples. In this paper, we have established a test system and tested the related performance indicators. The experimental results show that this image acquisition system of confocal laser endoscopy can achieve a 512×512 pixel imaging with the speed up to 15 frames/s, and correct each frame of the image in real time.

Infrared small target detection technology plays an extremely important role in military remote warning, satellite remote sensing technology, guidance and anti-mission, UAV detection and tracking, and other fields. Most traditional algorithms have high detection false alarm when there are thin and highlighted patterns in the background. To address the abovediscussed problem, this paper proposes an infrared small target detection algorithm based on multi-direction derivative and local contrast. The algorithm utilizes the two-dimensional Gaussian distribution of small targets to compute multidirectional derivative on each pixel of the image. Simultaneously, a sliding window is constructed to compute the local contrast. Finally, the derivative result and the local contrast is combined to get the target saliency map. Compared with traditional infrared small target detection algorithms in terms of background suppression factor (BSF) and signal-to-clutter ratio (SCR), our algorithms has better performance in both indicators. In addition, Receive Operating Characteristic (ROC) curve is introduced to evaluate the performance of the algorithm. The curve demonstrates that the proposed algorithm can achieve high detection rate with low false alarm rate preserved. The experimental results show that the proposed algorithm is simple, efficient and has high detection accuracy.

In this paper, we designed a compact Mie scattering lidar system for ocean-atmospheric horizontal visibility measuring and an algorithm used for obtaining the visibility of the aerosol. The effective range of our lidar system was from 300 m to 3 km with a 7.5-m horizontal range resolution and a 1-min time resolution. To reduce the uncertainty caused by using slope method which based on the hypothesis that either molecule or aerosol components exist in the atmosphere, we used the two-component fitting method to retrieve the aerosol extinction coefficient and the calculated the visibility based on Koschmieder’s theory. The whole system was powered by electricity supply which made it easy mounting on a ship or observation station by the sea. Lots of experiments were conducted laboratory to ensure the veracity and stability. In 2016 summer, we joined the cruise survey in China Bo-Hai and Huang-Hai Sea. Site experiments were carried out on the research vessel ‘Dongfanghong 2’. The results showed that the visibility values obtained by our system were in good agreement with the value set by the visibility meter and our lidar system was able to achieve visibility measuring under different weather conditions.

For the two-point spherical wave structure function, we propose a modified quadratic approximation, which can be used to investigate the second-order coherence properties (such as the beam spreading, average intensity, cross-spectral density function) of partially coherent beams through the turbulent atmosphere. We prove that the modified quadratic approximation, different from usual one, can be used to study the effects of inner and outer scales of turbulence, and is better than the usual one for a less coherent beam or for a very strong turbulence. A more accurately analytical expression for average intensity of Gaussian-Schell model beams is derived based on the modified quadratic approximation. These results are also illustrated by investigating the average intensity for Gaussian-Schell model beams in turbulence.

Ellipsometry is a kind of measuring techique to research the optical properties of materials by utilizing the polarization characteristics of light. The key of the optical ellipsometry is to utilize the polarization transformation that occurs as a beam of polarized light is reflected or transmitted through the dielectric film, and the characteristic parameters of this film can be obtained by measuring this transformation. In this paper, we present a novel scheme of ellipsometry that can extract the ellipsometric parameters of the reflected light from a single shot, which is achieved by using the vectorial optical field and digital image processing technique. In order to obtain the ellipsometric parameters of the reflected light, a zero-order vortex half-wave retarder is placed after the thin film to transfer the reflected elliptically polarized light to a vectorial optical field. When this vectorial optical field is analyzed by a linear polarizer, the transmitted light pattern with an hourglass-shaped intensity distribution can be obtained, and two gradual dark and bright areas show alternately. The azimuth angles and the intensity values of the central lines of dark and bright areas are related to the ellipsometric parameters, which can be obtained by processing the hourglass-shaped intensity image with our specially designed image processing algorithm. The theoretical model of our presented ellipsometer system is established firstly by using the Jones matrix theory, and the simulating and analyzing formulas are obtained based on the model. Some numerical analyzing studies have been carried out to validate the feasibility of our scheme, and the results of the simulated research indicate that the retrieved values of the ellipsometric parameters are consistent with the preset values.

Traditional methods usually show low detection performance, which is caused by the inaccurate evaluation of background statistical characteristics and the contamination of the anomaly. In response to these problems, this paper proposes a novel anomaly detection method based on collaborative representation of dictionary subspace. Since the prior information of the background and the anomaly is not known, the proposed method first utilizes mean shift method to cluster the original hyperspectral image (HSI). Then, some pixels in each category are selected as background dictionary atoms. Therefore, an representative overcomplete background dictionary can be obtained in this way. This dictionary can avoid the contamination of most anomaly pixels. Finally, collaborative representation is performed to detect anomaly targets by using the dictionary instead of the domain information of the pixel under test. It does not require modeling the background, which improves the accuracy of the calculation. Experimental results show that the proposed method outperform the other state-of-the-art methods.

Both common information and unique information are included in the infrared polarization (IRP) images and infrared intensity (IRI) images. Aiming at the disadvantages of (1) loss of detail information; and (2) poor discrimination of fused image information, during fusion of IRP images and IRI images, a method of multi-scale sparse representation and pulse coupled neural network is proposed. A non-local means (NLM) fusion methods combined with sparse representation of image and adaptive Pulse coupled neural network (PCNN) is included in the method. Firstly, the non-local means filter is used to obtain the image information of the source image at different scales. Secondly, a non-subsampled directional filter bank (NSDFB) is used to decompose the high-frequency information of different scales into multiple highfrequency direction sub-bands. For multiple high-frequency directions, the spatial frequency (SF) transformation is first performed for multiple high frequency direction sub-bands, and the PCNN is used to obtain the high frequency subbands fused image according to its significance, where the link strength of PCNN is adaptively adjusted by region variance. Then, the joint matrix composed with the low-frequency components is trained by K-singular value decomposition method (K-SVD) to get the redundant dictionary. The common information and unique information are judged by the position information of non-zero values in the sparse coefficient, and are fused with different methods. Finally, the fused high and low frequency sub-bands are inversely transformed by a non-negative matrix to obtain a fused image. Experimental results demonstrate that the proposed fusion algorithm can not only highlight the common information of the source image, but also retain their unique information. Meanwhile, the fused image has higher contrast and detail information. In addition, the fused image performs well in terms of average gradient (AG), edge intensity (EI), information entropy (IE), standard deviation (STD), spatial frequency (SF) and image definition (IDEF).

With the development of modern photoelectric reconnaissance and precision guidance weapons, infrared/millimeterwave composite reconnaissance guidance technology is more and more widely used, which greatly enhances the anti-jamming capability of photoelectric weapon system, and also puts forward higher requirements for the stealth protection of targets. In order to explore the protective effect of chopped carbon fiber material on the photoelectric stealth of the target, the thin films coated with chopped carbon fiber were prepared, and the experimental platform was constructed by using infrared thermal imager and millimeter-wave linear array imaging system. The effect of different areal density and different layers of chopped carbon fiber film on infrared/millimeter-wave imaging was tested. The results show that the coating of short cut carbon fiber film has obvious attenuation effect on infrared / millimeter-wave imaging. With the increase of the areal density of chopped carbon fiber, the influence of the film on the infrared/millimeter-wave imaging effect is significantly enhanced, the target contour is gradually blurred, and the attenuation of infrared imaging can reach 94% at the areal density of 9 g/m2. At the same time, it also has a good attenuation effect on the millimeter-wave. The effect of multi-layer superposition of chopped carbon fiber film on infrared/millimeter wave imaging is more obvious.

In order to overcome the high cost of manufacture and large volume or weight limitations, one solution is to arrange multiple sub-aperture optical systems in accordance with certain spatial rules. The stacking image of sub-aperture beam on focal plane is equivalent to large aperture optical system. However, due to the discretization of pupil distribution of sparse-aperture optical system, the signal-to-noise ratio of image is reduced, the modulation transfer function decreases at midband spatial frequencies, and the optical system errors increase. Aiming at the poor imaging quality of sparse-aperture optical system, in this article, the method of restoration algorithm based on improved Wiener filter and optimization of adjacent frames is proposed, which makes the restored video image have higher definition. The restoration algorithm based on improved Wiener filter and evaluate as well as optimize of adjacent frames in this article mainly contains four aspects, including the analyze of image degradation process, the establish of image restoration model, the evaluate of restored image’s definition, and the optimize of adjacent frame image. Firstly, Synthesize the effect of atmospheric transmission and array structure on image degradation, we have constructed an image degradation model and have calculated the degradation function under the model. Then, the restoration model based on Wiener filter is established and improved. Moreover, the definition evaluation factor of no reference image is built to measure the quality of the restoration image. Finally, construct the mapping relation between the adaptive constant K and the definition evaluation factor in Wiener filter, constantly optimize image restoration quality. In high altitude reconnaissance, remote sensing imaging and other fields, cameras are required to have very high resolution, so the algorithm in this article has great research value.

Background-oriented schlieren (BOS) is a novel flow visualization technology, which has the advantages of simple device, low cost, and quantitative measurement. In this paper, a BOS technique with two-dimensional color coding background is presented, which can be referred to as color background-oriented schlieren (CBOS). Different from traditional background schlieren technique, we designed a pattern combining ‘cosine dot’ and two-dimensional color coding as the background of BOS technique. Inspired by the coding principle based on De Bruijn sequence coding in the spatial coding method of traditional structured light coding technology, the pattern of ‘cosine dot’ is generated by multiplying the fringes in two perpendicular directions. In order to integrate the intensity value of cosine dots and corresponding encoded colors into a single pattern, and to separate them completely, the HSV color model is applied to address the problem. We calculate the perturbation degree of test flow fields by searching positions of the local intensity maximum of the cosine dot patterns with and without flow fields. The function of two-dimensional color coding is employed to locate the relative position of each local intensity maximum point. Finally, we carried on the simulation experiment and the real experiment to verify the feasibility of this method.

Infrared tracking and scanning continuous imaging is a typical remote detection system. However, the rotation of the carrier during the imaging period of the detector will cause image motion, which seriously affects the image clarity and resolution. A continuous rotating scanning medium-wave infrared tracking imaging system is designed in this paper. A image-stable mirror is added to the optical path to stabilize the image and optical axis by the synchronous reverse rotation of the image-stable mirror. On the premise of ensuring the imaging quality of the optical system, the image motion caused by 360° continuous rotating scanning of the system can be compensated in real time. The miniaturization and practicality of the whole system is also realized. The system proposed in this paper is a medium-wave(3μm-5μm) infrared scanning imaging system whose optical system consists of a telescope system and a re-imaging system. Through rotating the image-stable mirror respectively 1.04° positively and negatively, the image quality still meets requirements. Then the MTF change of the whole system in the temperature range from - 40 ℃ to 60 C℃ without rotating the imagestable mirror and focal length adjustment is simulated. After research and analysis, adjusting the eighth lens of the optical system along the optical axis can compensate the reduce of image quality caused by the change of temperature. Finally, the final machining tolerances are determined.

In order to improve the image reconstruction quality of multispectral correlation imaging system under the condition of low illumination, this paper proposes a multispectral correlation imaging scheme based on laser active illumination. In this scheme, the phase modulated multispectral correlation imaging camera is used as the experimental platform, and the laser is used as the auxiliary light source to increase the reflected signal intensity of the target object, and the image information of the target object is obtained through single exposure. The experimental results show that compared with the reconstruction results of multispectral association imaging under the condition of low illumination, the active and passive combination scheme can significantly improve the image reconstruction quality of the multispectral association imaging system. This paper is of great significance to promote the practical application of new multispectral imaging technology.

The Walsh function system has orthogonal completeness and is widely used in signal processing, image processing and communication. In this paper, three kinds of Walsh matrices, Hadamard order, Walsh- Like order and Paley order, are derived by Kronecker product based on row and block replication techniques of Walsh matrix, and the structural characteristics of different matrices are compared and analyzed. The generated Walsh matrix is used as the measurement matrix to modulate the optical field of the computed ghost imaging system. The simple binary object and the complex gray object are used as the target object, and the secondorder correlation operation is used to reconstruct the target object. The numerical simulation results show that the three matrices can reconstruct the target object with high quality under full sampling conditions, but the reconstructed image quality of Paley-ordered Walsh matrix is much better than Hadamard order and Walsh- Like order under low sampling conditions, which can effectively reduce the data sampling rate and improve the signal-to-noise ratio of ghost imaging system.

In this paper, a far-field pseudo-thermal correlation imaging system is proposed which is mainly composed of laser, thermal field modulation system, speckle far field emission system and high-sensitivity intensity fluctuation detection system, etc.. Because the correlation imaging system is based on the principle of intensity fluctuation statistical measurement, it needs to be reconstructed after multiple measurements. An image reconstruction algorithm based on compressive sensing is applied in this paper, which makes full use of sparsity constraints to effectively improve the image restoration effect. Finally, the feasibility of the method is verified by actual imaging test. The experimental results show that the proposed system can clearly image the remote target and obtain better recovery images under the same sampling times.

Panoramic annular lens (PAL) system consists of a panoramic head block unit and a relay lens system, adopting a plane cylindrical projection method to project a cylindrical field of view around the optical axis 360° into a two-dimensional planar annular region to realize super hemispherical imaging. PAL system requires large field of view imaging on a limited image plane, which inevitably results in lower image resolution and poor local detail imaging. However, the information processing speed gets faster with the development of 5G, which leads to a growing demand for better image quality and clarity. This paper presents a PAL system matching image sensors with 4K resolution, which can demonstrate the details about the object and get a smooth and ultra-high definition image. Unlike other sensors, it has large image faces and tiny pixels and the effective number of the pixel is about 24.3 million (4K × 6K). The proposed PAL system has 6 sets of 9 lenses with compact structure. The F-theta distortion of the full field of view is less than 1%, and the modulation transfer function value of each field of view is greater than 0.5 at the Nyquist spatial frequency of 130lp/mm which approaches diffraction limitation. The designed system has good imaging quality and meets the application requirements.

How to effectively detect weak targets from complex background is always a challenging problem and is a meaningful research subject with practical significance. In this paper, the complex video frame images are considered as a spatial random process, and the stationarity and low-rank characteristics of different components of the image are related to theirs statistical characteristics. According to this view, a statistical block low-rank background modeling algorithm (for short: SBLR) is proposed. This paper first analyzes the regional statistical characteristics of the image, and then uses k-mean statistical clustering algorithm to divide the image into statistical blocks to obtain the statistical block images. Then, the characteristics of each component of the statistical block image are analyzed to establish a model composed of statistical block low rank background and sparse components. Next, according to the characteristics of each component of the model, the solution scheme of principal component analysis is adopted, and the specific solution algorithm is given. Finally, the background reconstruction experiment according to SBLR algorithm and target detection experiment are carried out. Experiments show that the algorithm proposed in this paper achieves good accuracy in the background reconstruction of complex scenes, the background is significantly suppressed, the target is significantly enhanced, and the target detection rate is high.

With the developing of space optical remote sensing from understanding the earth to exploring the universe, the development of optical systems for space optical remote sensors is becoming more and more demanding. In the deep space exploration mission, the target signal is weak relative to the background signal. In order to improve the detection sensitivity of the system, and in order to reduce the influence of background radiation on the observation and to pursue the maximum performance of medium and long wave infrared detection, we need to reduce the temperature of the optical system and detector to a low temperature as much as possible. Therefore, the application of cryogenic optics will become more and more important. We can foresee that cryo-space optics will become an important development trend of optical remote sensing. In the development of cryogenic optical systems, it is a very important task to determine the performance of materials in cryogenic environments. The cryogenic properties of certain materials have been tested and some useful data have been obtained in the world.

Aiming at the requirement of high precision real-time measurement of attitude angle in modern manufacturing industry, an attitude measurement system based on a Laser Tracker is constructed. A method of attitude measurement based on 2DPSD and monocular vision is proposed, and a target structure for realizing this method is proposed. Firstly, the rolling angle of the target relative to the camera is calculated by monocular vision, and the laser beam vector is obtained by Laser Tracker and 2DPSD. Then, the relative attitude between the Laser Tracker coordinate system and the camera coordinate system is calculated based on SVD. Finally, the transformation relations of unit vector of laser beam in different coordinate systems are established to calculate the attitude of target relative to Laser Tracker. Experiments show that the method can effectively measure the target attitude information, and the maximum error of attitude angle measurement can be less than 2° within the effective angle range of [- 25°, 25°] and distance range of 3m.

In the absolute distance measurement of the non-cooperative target laser, the backscattering characteristics of the long-distance, real-machined surface are complex, and the parameters such as the incident azimuth angle, the incident angle, the surface texture, and the roughness are all have an impact to the real surface backscatter field distribution. Usually in the long distance, the distance measurement fails because the backscattering energy is weak. Therefore, the above parameters directly affect the absolute ranging range and accuracy, which is also an important bottleneck restricting the development of absolute ranging technology without cooperation targets. Aiming at this problem, a method to improve the range of actual machining surface ranging is proposed. According to the data collected by the ranging system, a multidimensional parameter inversion model of machining surface is constructed. This method can reverse the parameters such as the incident azimuth, the incident angle, the texture of the surface to be tested, the roughness and the processing method. It is verified by experiments that the actual surface processing method can be accurately distinguished under the inversion method, and the accuracy of the incident azimuth angle and the measured surface roughness inversion is also high, and the relative inversion errors are 1.20% and 1.01%, respectively. It is verified by experiments that the inversion of surface parameters greatly broadens the range of absolute distance measurement of non-cooperative target laser.

Due to the backscattered light and signal attenuation, the underwater imaging could be severely degraded by the scattering media, especially in the case of strong scattering for dense turbid medium. Considering the circular polarization light can persist better its polarization property during propagating through turbid media compared with the linear polarization light. In this paper, we two polarimetric recovery methods based on the circularly polarized illumination. The first one is based on the combination of both linearly and circularly polarization information. The second one is an improved method for recovering the underwater image by combining histogram analysis. The real-world experiments shown that, by using circularly polarized illumination, the traditional polarimetric dehazing method is optimized which is suitable for use in the strong scattering environment, especially when the method is combined with histogram stretching.

Infrared thermal imager has developed rapidly in the field of military and civilian applications. How to objectively evaluate the imaging effect of the infrared thermal imager has become a problem that must be solved. Which not only provides quantitative mathematical description for the imaging performance of the infrared thermal imager, but also provides the supporting basis for the study of the image sharpness, target detection distance and target tracking performance of the infrared imaging system. The imaging evaluation system of thermal infrared imager proposed in this paper has the functions of infrared image data acquisition and processing. It is used to test and evaluate infrared image data in coordination with the target system of infrared imaging evaluation (composed of blackbody, radiation target console, collimating optical system and digital display precision turntable). The system has designed the main performance indexes, mathematical model and steps of image evaluation, including image non-uniformity, Signal Transfer Function (SiTF), Noise Equivalent Temperature Difference (NETD) three indicators to evaluate the noise and response characteristics of infrared thermal imager, and Angular Linearity, Target Imaging Positioning Angle Error two indicators to evaluate the image resolution characteristics of infrared thermal imager. After system testing, the performance is very superior and it becomes the necessary debugging and testing equipment in the development of infrared thermal imager.

An absolute cryogenic radiometer (ACR) has been developed at the National Institute of Metrology of China. The system was built based on a mechanical cooling system, with a cavity receiver working at 5.2 K and a noise-equivalent power of ~2 nanowatts. The ACR cavity receiver was made from pure copper by electroplating, weighing only <1 g. The inner surface of the ACR cavity receiver was coated with a polymer material mixed with carbon nanotubes which is absorptive in a wide spectral range from 250 nm to above 16 m. The relative standard uncertainty for the calibration of optical radiant power is 0.042% at near 100-microwatts level and 0.22% at near 1-microwatt level. The ACR system can be utilized for not only optical radiant power measurement but also irradiance measurement with a precision aperture of a calibrated area, and then can be used as laboratory irradiance standards, remote sensing detectors, and pyrheliometers. The ACR system can also be employed for total radiance measurements with precision measurement results on the effective areas of precision apertures and the distance between the precision apertures, in the cases that the measurement target overfills the field of view of the system. The distance between the precision apertures needs to be measured inside the cryogenic and vacuum chamber and hence in-situ measurement by time of flight method with an uncertainty of less than 0.1 mm was adopted. The ACR system can be then applied to calibrate the total radiance of a blackbody radiation source with a working temperature as low as 100 K with a relative standard uncertainty better than 0.5% and determine the effective radiant temperature with an uncertainty to <150 mK level when the emissivity of the blackbody is near unity. The ACR system can be further extended for spectral radiance measurements using band-limiting optical filters. The spectral transmission of the band-limiting optical filters can be used by laboratory spectrophotometers; but for higher accuracy, an integrating sphere source illuminated with a monochromatic light with tunable wavelength can be used for the spectral transmission measurement to eliminate the angle effect resulted from the spatially dispersive rays. Also, optical density outside the desired bandwidth of the band-limiting optical filters should be carefully analyzed. After the spectral radiance measurement at certain wavelength, the spectral radiance of the radiant source over a wider spectral range can be extrapolated by measuring the spectral diffuse reflectance over the interested wavelengths.

Crack in microchannel plate (MCP) seriously reduces the mechanical and electrical properties of MCP. The mechanism of crack propagation in the chemical treatment process was revealed by studying the changes of crack morphology in acid-alkali etching and hydrogen reduction. The results show that during the acid-alkali etching process, the cracks on the channel material is dissolved by the dilute HNO₃ and the cracks on the channel wall expands gradually under the etching of the NaOH solution. During the reduction process, cracks do not change significantly at the stage of heating. While at the stage of reaction with H₂，the cracks are more easily expanded. The length of cracks does not change significantly after reduction. However, the surface near the cracks warps and the depth of cracks increases.

In order to quickly deal with a large number of multi-source small-size remote sensing images produced by such as unmanned aerial vehicles (UAV) remote sensing, to meet the requirement of high performance parallel processing for earthquake emergency response. Based on analysis of various parallel processing technology of remote sensing images, OpenMP and multithreading technology are comprehensively used to parallelize the image processing algorithms at coarse and fine-grained levels. Combining with the advantages of network multicast technology, the parallel processing system for multi-source small-size remote sensing images is designed and implemented. The system has a strong expansibility in dealing with the types of the images, processing algorithms and the number of processing nodes. After the experiment on a cluster consisting of two computers, it is proved that the system has high CPU utilization and data throughput efficiency, which can provide platform support for earthquake urgent processing.

LiDAR (light detection and ranging) has recently been recognized as one of the most promising remote sensing techniques due to its excellent performance in the detection of forest inventory, topographic mapping, and automatic driving. Compared to discrete return systems that can provide only range information with a limited number of backscatter intensity value, the full-waveform LiDAR systems record the entire backscattered signals containing more comprehensive geometric physical information, such as depth, shape, and reflectivity, of the target. Waveform decomposition techniques are commonly used to extract attributes of targets from LiDAR waveforms, which consider the received waveform as a mixture of one or more standard probability distribution functions after linearly stretch in the range and magnitude directions. However, the new exponential decomposition algorithm proposed in this paper considers the received waveform as a superposition of several system waveform after linear translation and scaling transformation. The system waveform is fitted by several exponential functions, thus the received waveforms can be treated as similarity transformation of the functions. In the experiment, the method was verified using a system waveform with a negative tail. The significant improvement in range accuracy and reduction of waveform fitting residual indicated that the proposed method can deal with LiDAR waveforms with negative tails and has the potential to extract more accurate structural parameters of the detected object.

In this paper, a long wave infrared continuous zoom optical system is designed based on 640×512 element cooled detector. By using fluoride crystal and chalcogenide glass to design the passive athermalized optical system, the operating temperature range of the optical system can meet the requirements of -40~60℃.The spectral wave band of the system is 7.7μm~9.5μm with F# is 3. It can realize 30mm ~150mm continuous zoom. When considering athermalization of infrared optical system, the fluoride crystal glass, the chalcogenide glass and the other infrared materials are matched reasonably. And three athermalized schemes are designed in this paper. By comparing the three design schemes, it can be concluded that the addition of fluoride material to the long wave continuous zoom system is beneficial to the realization of passive athermalized design.

A binocular 3D sensor vision system is made on the demand of 3D measurement of teeth surface profile and the invisibility of part of the teeth profile for the result of its complexity. This system adopts line laser to illuminate perpendicularly based on laser triangulation measurement principle which is simple and precise. We use the improved threshold barycenter method to extract the light center, which removed interferences of diffuse reflection and promoted accuracy. On this basis, we use two cameras to photograph the teeth model to calibrate this system by way of polynomial fitting. After that, we use ICP algorithm to fuse 3D point clouds of the teeth model collected by two cameras, and then the 3D reconstruction of teeth model is carried out through surface interpolation. The experimental results excellently showed the teeth model surface profile.

In the traditional 3D measurement systems based on phase shifted structured light, the structured light is usually generated by raster projection. But the optical system by using this method is a little big in size for the endoscope. This paper proposes a method for generating structured light based on bundled fibers, which can solve this problem. However, it was found in experiments that the structured light projected by this method is deviated greatly from the standard sinusoidal fringe. In order to compensate for the error caused by the unsatisfactory structural light, we propose a calibration algorithm. To verify the phase compensation algorithm, we had built an endoscope system using the arranged fiber bundles. On the wedge objects with different tilt angles, the measurement error of the phase is improved more than 30% after using phase compensation algorithm. Then, the plaster model with complex surface was used in the experiment. The result indicated that the measured shape of the model is more precise after phase compensation. It is shown that the proposed phase compensation algorithm can effectively correct the error of phase measurement caused by non-sinusoidal structured light in the endoscope system.

Traditional endoscopes can only display common images of diseased tissues and difficultly detect early canceration in the digestive tract. With the continuous development of endoscopic technology, Fuji Intelligent Chromo Endoscopy (FICE) is widely used as a kind of simulated staining endoscopy technology. Compared to common images, FICE enhances the contrast of the image and can show the fine structure of the digestive tract mucosa more clearly. Because the white light illuminates the object, FICE is hard to observe capillaries in the superficial layers of the mucosa. In this paper, a bluewhite light imaging method is proposed, which combine a mixed light of a narrow-band blue light and a white light to illuminate the object with FICE technology to enhance the capillaries and maintain the images with certain brightness and background characteristics. Through the adjustment of the luminous intensity of blue light and white light, the optimal light intensity ratio range are determined by two evaluation indicators: the image’s pixel value difference and the blood vessel quantity difference. The results show that the deficiency of FICE technology can be compensated when the image’s pixel value difference is below 0.25 and the blood vessel quantity difference is below 0.1.

Highly reflective diffuse boards or integrating spheres illuminated with lamps are routine laboratory equipment for 2D radiometric calibration. The traceability chain to validate the measurement results is from absolute cryogenic radiometer (spectral power and then spectral power responsivity) through filter radiometer (spectral radiance at single wavelength), standard blackbody radiation sources (spectral radiance over a wavelength range), and calibrated spectroradiometers (spectral radiance responsivity over a wavelength range), to the large area spectral radiance sources for large area optical sensors and imaging spectroradiometers. However, due to (1) the fairly long traceability chain, (2) the non-uniformity of lamp illuminated diffuse boards and integrating spheres, (3) the relatively low spectral power from the broadband source for high spectral resolution, and so on, the calibration uncertainties for spectral radiance and irradiance responsivity are above the level of a few per cents. In order to improve the calibration performance, tunable lasers have been widely adopted to generate a large, uniform radiometric calibration source. For instance, an integrating sphere can be illuminated with a wavelength tunable laser to form a good spectral radiance field. Though very high laser power is necessary if the exit port of the integrating sphere is large. An alternative way is to directly unify and expand the laser beam for a good spectral irradiance field. In this work, we built a large, uniform, spectrally tunable irradiance field based on a Ti-Sapphire laser. First, two double-convex lenses were employed as a beam expander; second, a rotary diffuser was placed at the common focal point of the two lenses; thirdly, the expanded optical beam was then delivered onto and through a micro lens array to form a highly uniform spectral irradiance field with a size of 30 mm by 30 mm. The non-uniformity was measured to be 0.24% over a 20 mm by 20 mm area. The total optical losses through the beam expansion and unification system would be significantly reduced compared with integrating sphere method. The traceability chain is from the absolute cryogenic radiometer (spectral power and then spectral power responsivity) and the effective radiometric aperture area to the photodetector with a precision aperture (spectral irradiance responsivity), and then to the large, uniform, laser-based spectrally tunable irradiance field (spectral irradiance) for the calibration large size optical sensors and imaging spectroradiometers. The traceability chain is short, the non-uniformity is low, and the signal-to-noise ratio is high, compared to that based on the lamp illuminated boards and integrating spheres. Furthermore, the laser-based spectral irradiance field can be easily converted to a large, uniform spectrally tunable radiance field by simply placing a large-size, highly reflective diffuse board in the irradiance field. The laser-based irradiance and radiance field would play an important role for radiometric calibrations with low uncertainties.

Reverse engineering is an important product development mode in industrial design. Reverse development can shorten the product development cycle, reduce costs, improve product quality and meet people's higher needs. Threedimensional measurement technology is the first step and key technology of reverse engineering, so it has become an important factor affecting product reverse development. It takes the product design based on reverse engineering as the entry point, and expounds the difference between contact and non-contact measurement method, and the suitable product form. At the same time, it takes the non-contact measurement method as the research object, analyses and comparisons the measurement principles and characteristics between structural light measurement method and binocular stereo vision measurement method, discusses the application in product reverse design of the two methods, so as to so as to provide some help for product design based on reverse engineering.

Dynamic speckle analysis is a highly sensitive approach for monitoring speed of processes, which cause change in micro-topography of the surface of 3D objects. The raw data are speckle patterns formed on the surface under laser light illumination. Statistical pointwise processing of correlated in time speckle patterns yields a 2D map of the ongoing activity, that shows regions of faster or slower fluctuations of laser light intensity. The map is a distribution of a given estimate, which is contaminated by signal-dependent noise due to averaging over a finite number of speckle patterns. For this reason, efficiency of processing is frequently addressed topic. This paper studies the impact of the speckle contrast on quality of the activity map characterized by the spread of the probability density function of the activity estimate. It has been shown by simulation and experiment that retrieval of different activity regions is effective at low contrast of the speckle patterns.

Single-photon LiDAR offers single-photon sensitivity and picoseconds timing resolution, leading to high-resolution three-dimensional (3D) images. In this paper, we investigate the reconstruction of 3D images from data acquired using a custom designed time-of-flight scanning transceiver based on the time-correlated single-photon counting LiDAR. The system comprises a pulsed laser source at 1064nm wavelength, a monostatic scanning transceiver and a superconducting nanowire single-photon detector. The maximum distance of ranging finding under the experimental environments is up to 95.1km, and high-resolution 3D image of a pavilion is reconstructed at the range of 2.9km. A total variation restoration optimization algorithm is performed to reduce the acquisition time of the entire 3D images. Experimental results show that this system is feasible for imaging at longer range by refining the setup, and have potential for target recognition.

From April 24 to 25, 2019, a characteristic floating dust event occured in Kashi, one of the most important cities in Xingjiang province, China. The Dust Aerosol Observation (DAO) field campaign captured this case and provided us with comprehensive ground-based observation to research this floating dust case. The instrument involved in DAO field campaign included particles monitors, gas analyzer, nephelometer, radiometers, and lidar, among others. Meanwhile, CALIPSO were used as a satellite remote sensing observation to perform auxiliary analysis. Furthermore, to give the case a further quantitative description and get a deeper insight of the interaction mechanisms, WRF-Chem which is a regional air quality model calculating meteorological and chemical field on line were adopt as well. According to comprehensive observation and simulation, we divided this floating dust case into two periods. Different periods have different aerosol sources. The first period is before 14 o 'clock on the 24th. The main aerosol source was dust transported from the edge of the Taklimakan Desert by east wind at a height of 3-5km. In this period, PM10 concentration increased to 4000μg·m-3 and PM2.5 concentration increased to 800μg·m^-3 in a short time. In the second period, due to the diversion of wind direction, dust transfer reduced and stopped gradually. Because of the circulation background and weather condition, the combined effect of local accumulation and reaction of pollutants still maintained particles concentration at a high level. In this period, although PM2.5/PM10 more than the ratio in the first period, it still kept around 0.3. PM10 and PM2.5 concentration both maintained a slow decline.

Geiger mode avalanche photodiode arrays(G-APDs) is emerging high-sensitivity laser signal detectors in recent years, which can be applied to photon-level lidar detection, guidance and imaging. Because of its photon-level detection sensitivity, it is greatly affected by the strong skylight background and its own dark count. In order to reduce the noise interference such as dark count and strong skylight background, based on the detection techniques such as spectral filtering, spatial filtering and temporal filtering, a noise filtering technique based on neighboring pixel threshold detection is proposed. Through modeling analysis and related experiments, it is verified that the noise filtering technique based on neighboring pixel threshold detection can effectively improve the detection probability and ranging accuracy of laser single-pulse echo signals.

Normalized Differential Vegetation Index (NDVI), usually calculated by surface reflectance at red and near-infrared bands (NDVI_Surf), which is an essential index in remote sensing. NDVI_Surf is generally used to discriminate different surface cover types and adopted in many surface models as a vital adjustable parameter to estimate the surface reflectance in remote sensing aerosol retrieval. However, NDVI_Surf is challenging to obtained directly and usually calculated by the red and near-infrared reflectance at the top of atmosphere (NDVI_TOA). NDVI_TOA is very susceptible to the atmosphere with different angles. If NDVI_Surf is replaced by the NDVI_TOA, it will cause an error of surface reflectance estimation and then make the wrong aerosol retrieval. In this study, Second Simulation of a Satellite Signal in the Solar Spectrum, Vector version (6SV) radiative transfer code was used to analyze the effects of NDVI_TOA on a surface Bidirectional Polarization Distribution Function (BPDF) model under different atmosphere and multi-angles conditions. The results display that the NDVI_TOA decreases with the rise of AOD. Within scattering angle (SA) of 60° to 115°, the influences of NDVI_TOA on BPDF are great and increases with the AOD reduces. Within the SA between 115° to 180°, the effects of NDVI_TOA on BPDF are small and remain unchanged with the AOD decreases. The simulation and analysis results have a great significance for polarized aerosol retrieval.

In this paper, based on the principle that signals only occurs on a few time-bins (timing accuracy of a modern TCSPC module) due to short period illumination and the noise which is almost a constant for all bins, we designed an algorithm for denoising by using signals from multiple detectors and further improving the performance by adopting signal processing technique (e.g. median filtering). To exploit the information from the histograms efficiently, it is necessary to choose the gating width in an appropriate range, so that a well-placed window is large enough to capture most of signals, but without accepting too many noise. Whether to accept the signal is determined by weighting signals from multi-detectors within each gate width, where only multiple detections are recorded during the period can be accepted, otherwise detection is considered as noise and removed in the final reconstruction. Thus the three-dimensional information (the twodimensional spatial information and the depth information) of the target can be obtained accurately. In the algorithm, the results are evaluated numerically by signal to reconstruction error (SRE). The advantage is learned by comparing with several classic methods, the data used in this paper are derived from a mathematical model which account for Poisson statistics and Lidar equation.

It is one of the main coupling ways of broadband high power microwave pulse to enter into the electronic equipment in the form of field line coupling and produce effect. However, both the field and the coupling signal test data contain a certain interval of dispersion, which may conceal the inherent law of the field line coupling effect. In order to clearly understand and quantify the inheritance of the two signals, a large sample of field and single-core cable coupling signals were tested based on the plate-cable model, and the parameter characteristics and distribution of the two sets of impulse signals were statistically analyzed, and the inheritance between them was tested. This method and result can help to deepen the understanding of the internal law of field line coupling and extend the application to the determination of field-to-cable coupling transfer function.

Detecting fast-moving particle receives more and more attention both in physics and biology, and the study has shown its significant value either in supersonic speed or in movement of tiny biological particles. A significant amount of preparatory work has already been done to optimize this study. Always using multiple cameras or increasing the distance between detector and target, researchers can obtain favorable results. However, As the application of this technique increases, more and more challenges are emerging. One of the most obvious limitations is that confined space to lay detector. In some sense, rotating mirror can be introduced to make the system compact. It is necessary to analyze how to bring in mirror and built the system. Here, in order to use mirror capturing fast-moving target, we take a piezoelectric actuator to drive mirror, thus adopting a high angular rate to adapt to compact environment. Besides, A series of mathematical formulas and relational model are established to guide the construction of this system. Another advantage of the system, synchronous trigger signal can be triggered by laser and other means wirelessly with high precision. Therefore, having the aid of rotating mirror and wireless trigger, a fast-moving target detection system that has the virtues of no restriction of space is completed. In order to make this system in a successful operation, it is of importance to set up light path under the guidance of theoretical analysis. The experiment of trapping particles can be an effective method to show the system workflow.

Binocular stereo vision combined with structured light technology has developed rapidly in recent years. We have studied the blob extraction and matching algorithm of randomly distributed infrared speckle structured light, proposed an improved blob detection algorithm based on Laplacian of Gaussian (LoG) operator, which combines the contrast of the blob, the intensity difference and statistics between the center and edge pixels of the blob. The improved blob detection algorithm can extract the blobs of various scales and brightness effectively at one time, and restrain the influence of edges, bright strips and corners. According to the randomness of projected dot distribution, a matching method based on the characteristics of surrounding blob distribution is proposed. In order to solve the correspondence problem, we attach a descriptor to each blob. The descriptor at a reference blob center captures the angle and distance of the remaining blobs relative to it. In a small local region, the corresponding point sets in the two images are approximately affine transformed, and the transformed point sets have similar descriptive values. Experiments show the feasibility and correctness of this improved blob detection algorithm and matching method.

The multi-focus image fusion technique is to extract the focus regions from source images and compose them together to form a clear image in the full field of view. In order to further improve the accuracy of focus region detection and ensure its efficiency, a novel multi-focus image fusion method in spatial domain, based on guided filter and mixed focus measure, is proposed in this paper. Firstly, a guided filter is employed as an edge-preserving smoothing operator to process the source images, and the difference operator is used between the filtered images and the source images to extract salient feature. Subsequently, the salient feature maps are measured by the mixed focus measure, combining the sum of energy of edge (SEOE) and the sum of local variance (SLV), to detect the focus regions, and the initial decision map is obtained. For holes of different sizes in the initial decision map, the closing operation and the small area removal strategy are used to fill and connect the truncated regions, and then the opening operation and the guide filter are used to optimize the decision map boundary to obtain the final decision map. Finally, the multi-focus fusion image is obtained by the pixel-wise weighted-averaging rule according to the final decision map. Simulation results demonstrate that the method is superior to some existing fusion methods on both subjective visual perception and objective evaluation metrics.

For recent years, with the development of manufacture, free-form surfaces are widely used in optical systems because of the degrees of freedom and the capacity of correcting optical aberrations. Nowadays, commercial optical design software such as Optics Studio are commonly applied to optimize an optical system from a suitable initial structure to obtain high-quality imaging characteristics. The initial structure optimized by software must include the surface types and its parameters. Notice that the free-form surface type is unknown, let alone the parameters. Therefore, the initial structure of a free-form surface cannot be designed by commercial optical design software directly. The software cannot optimize or analyze the system with free-form surfaces either. This paper proposed an integral design method of optical system with free-form surfaces based on theoretical calculation and optimization of optical design software. Firstly, Fermat’s principle, equal optical path length between object and image, is applied to calculate the sampling data points of the free-form surface. Data points are fitted using least-square fitting algorithm to obtain a the surface type and its parameters, which are used as the initial structure. Secondly, a commercial optical design software further optimize the optical system containing the free-form surface. Not only the free-form surface but also other parameters can be optimized by the software. With the powerful functions of image quality and tolerance analysis of the software, we can obtain a high-quality imaging system with free-form surfaces in a short time. This method solves the problem that commercial software cannot design optical systems with free-form surfaces directly. Meanwhile initial structure with free-form surface can be acquired directly by this method. In addition,the powerful functions of the software such as optimization, image quality and tolerance analysis are fully utilized in the process of integral optimization. Since the system will be further optimized by the software, a small amount of sampling data points is enough to calculate the initial structure which speeds up the calculation. A passive ranging and three-dimensional imaging system with chiral phase mask is designed as an example. Different from conventional imaging system, two image points will be obtained by the system when one point is used as the object. Apparently, it is difficult for any commercial optical design software to design. The novel integral method proposed in this paper is applied to this system.Firstly, the system is designed in reverse sequence for the sake of simplification. A doublet with effective focal length 200mm and f-number 8 is used as the initial structure. Two points at (0,0.3,256.1) and (0,-0.3,256.1) are used as Please verify that (1) all pages are present, (2) all figures are correct, (3) all fonts and special characters are correct, and (4) all text and figures fit within the red margin lines shown on this review document. Complete formatting information is available at http://SPIE.org/manuscripts Return to the Manage Active Submissions page at http://spie.org/submissions/tasks.aspx and approve or disapprove this submission. Your manuscript will not be published without this approval. Please contact author_help@spie.org with any questions or concerns. the “object” which will image at (0,0,-63.6) as the “image” in the reverse sequence. A free-form surface is added in front of the doublet, thus the whole system turns to a triplet system. 6X12 sampling data points are calculated to fit an XY polynomial surface. Secondly a commercial optical design software further optimizes the optical system with the free-form surface. Finally, we obtain a high-quality imaging system with a free-form surface. The MTF (Modulation Transfer Function) performance of the system is closed to diffraction limit.

In this paper, a novel optical inspection apparatus was studied which enables one to inspect both top and bottom surfaces of the thermoelectric cooler (TEC) components. In the optical inspection apparatus, a right angle prism reflector located beneath the glass stage was used to image the bottom surface of the TEC component on top of the stage. In order to obtain the clear images of two surfaces of the TEC component simultaneously, a proper telecentric imaging lens with sufficient large depth of field needs to be selected to address their optical path difference. A telecentric optical imaging lens DH110-03F50 with depth of field of around 6mm together with a right angle prism reflector with solpe side length of 3.6mm was chosen for this experimental setup. With this apparatus three groups of components were inspected in the experiments and each group has some typical samples with specially selected Passed and Failed features on the surfaces to be examined. The experimental results indicate that the images of both top and bottom surfaces obtained using the optical inspection system are sufficiently clear and well resolved which meets the requirements for the following image processing. The results show that the proposed technique allow us to inspect both top and bottom surfaces of the component with simplified configuration and effective cost. This novel inspecting technique will find applications in the automatic optical inspection systems for the TEC components.

Catenary is an important part of electrified railway, and its geometric parameters are important parameters reflecting the safe and stable operation of locomotives. With the improvement of its speed, there are higher requirements for high-accuracy and real-time detection of geometric parameters of catenary. The existing systems have problems of long sampling interval, low real-time performance, and light-sensitive. Aiming at the actual requirement of dynamic measurement of catenary geometric parameters, a non-contact catenary geometric parameter detection system based on machine vision was developed. Firstly, a measurement model based on high-power line lasers and high-resolution area cameras was established to meet the application requirements. The measurement principle of the system was analyzed and the detailed formulas were deduced. Secondly, image difference, laser spot roundness analysis and other image processing algorithms were used to quickly and accurately detect the characteristics of laser points on the contact line with complex background. Based on the measurement model and algorithms mentioned above, the hardware and software platform of the system were built, and fast image acquisition and processing was realized by using multi-thread programming technology on high-performance industrial computer, which solved the problems of long sampling interval and low real-time performance during the measurement. Real-time image storage and display and preservation of detection results were realized in the software. Finally, a preliminary experiment was performed on the prototype, and the accuracy of the measurement results was analyzed. Experiment results showed that the system works stably and has high accuracy, which meets the practical application requirements.

Affected by the sensor itself, illumination, atmosphere, terrain and other factors, even if imaging the same region at the same time, the spectral characteristics of ground objects in different remote sensing images are also very different, and the surface parameters, ground object classification and target recognition results of the inversion are also different, which brings great uncertainty to quantitative analysis. The relative radiation correction effect of PIF, method is obvious and the operation is simple, and the accuracy of the effect depends greatly on the selection of the PIF point. The general relative radiometric correction methods are linearization correction without considering the nonlinear difference of multi-temporal images. At present, most radiation normalization methods assume that the transformation relation between images is linear, extract PIF points and establish radiation transformation model. In this paper, Kernel Canonical Correlation Analysis (KCCA) is used for the first time to normalize the radiation between multi-temporal hyperspectral images, which can greatly reduce the nonlinear difference in relative radiation correction. Based on the theory of nuclear canonical correlation analysis, the radiation normalization method of multi-temporal aerial hyperspectral images is proposed. The feature points of PIF are extracted in the nuclear projection space, and the nonlinear model is used for the radiation normalization of hyperspectral images, to improve the radiation normalization accuracy of multi-temporal hyperspectral images. Compared with Canonical Correlation Analysis (CCA), the number and precision of PIF point extraction can be significantly improved. This method can satisfy the radiation normalization between aerial hyperspectral multi-temporal images.

Measurement systems based on laser spot triangulation are widely used in many fields of distance-, surface and 3D measurements. Currently, strong interest in applications like laser-range detection (LIDAR) in automotive driving and robotics also promote further research in improving the technique. Laser-based ranging and triangulation techniques suffer from the great advantage of one of the lasers properties - its coherence. A coherent laser light ray allows projecting a spatially small spot onto an object compared to a broadly illuminating LED or bulb. A detector, e.g. camera or photodiode, detects the reflected measurement spot precisely with its position on the object. The downside of the coherence appears in combination with a rough reflecting surface as speckles. Speckle is the noise of the spot due to the rough object surface and the resulting random phases. In some measurement settings, the speckle noise has a large negative effect and influence on the measurement uncertainty to determine the precise center-of-gravity of the measurement-spot's position. In this contribution, we investigate a method introduced by us in an experiment to reduce the speckle noise and therefore improve the measurement uncertainty in triangulation. The proposed multi-spot-scanning method decorrelates speckle noise patterns through dynamical holography of the laser-spot by varying the position microscopically. For the dynamical scanning of the spot, we use a spatial light modulator (SLM) being addressed with digital holograms. SLMs are part of many measurement systems and other optical applications, especially projection-based systems. The holograms, illuminated by the laser, microscopically translate the measurement spot position in the object plane. These so-called "miicro-variations" are in fact translations of the first diffraction order using a grating on the SLM with additional overlaid Zernike-polynomials. The grating has a carrier frequency calculated according to the SLM's pixel size. Due to the micro-variations, the speckle noise patterns vary and decorrelate. Integrating or averaging over many patterns on the camera then allows predicting the spot's position with higher certainty through its better uniformity. Additionally, we examined how well the speckle decorrelation affects the uncertainty reduction especially in a triangulation sensor setup. Our experiments, utilizing the multi-spot-scanning method, showed promising first results. The microvariations in our experiments corresponded well to the simulations. Using different Zernike-coefficients, we are able to control the spot position to roughly a couple of micrometers while having a maximum field size for micro-variation of up to 16 mm in diameter. The best micro-variation-spot radius was between 75 μm and 85 μm considering a spot size of FWHM = 53 μm. We also found out, that with the method we could decorrelate speckle patterns to a certain degree. This degree can reduce the noise while averaging by a factor of around 40% compared to the original noise. Overall, the statistical measurement uncertainty improved by the reduction ratio of approximately R = 3 in axial direction. Further investigations on more spot-variations (7-42 spots) lead to solely slight improvements, because the denser the spots are, more overlap is present and less microvariation and decorrelation is possible. Furthermore, we have investigated different Zernike-polynomials (coma, defocus and astigmatism) and their influence on combined variations. In conclusion, we describe a method for laser-triangulation sensor systems to reduce laser speckle noise and improve measurement uncertainty. With this method, we can increase the axial resolution of the triangulation with the disadvantage of losing a small amount of lateral resolution due to the averaging and variation of the spot. We hope to be able to also expand our findings to other scenarios and setups as well as improve the findings with further research.

The principle of Gas Identification Method for Long-Wave Infrared Hyperspectral Imaging based FTIR was described in detail． The method of spectral data preprocessing and calibration，radiation transfer mode， algorithm of identifying and concentration retrieving of chemical gas，the detection limit and detection distance were analyzed． The development situation of passive IR remote sensing for chemical gas cloud detection technique was investigated，as well as the key parameters of them．

It is important for the convergence of model wavefront-sensorless (WFSless) adaptive optics (AO) system that how to generate base functions and their numbers of order. The convergence speed of model WFSless AO system depends on the number of eigenmodes when eigenmodes of deformable mirrors (DM) are used as base functions of model WFSless AO system. In practice, lower order aberrations occupy the majority. In order to accelerate the convergence rate of model WFSless AO system, this paper uses partial low-order modes of eigenmodes as base functions of the system to analyze its convergence speed and correction capability. Simulation results demonstrate that the convergence speed of the system is improved to a certain extent regardless of the intensity of turbulence when the correct ion effect reaches 80% of all-order modes of eigenmodes. For the same wavefront aberration, the more the number of actuators is, the bigger the optimization of the convergence rate of the model WFSless AO system is.

The starlight navigation is considered to be one of the most important methods for spacecraft navigation. Starlight simulator system is a high-precision system with large fields of view, designed to test the starlight navigation sensor performance on the ground. A complete simulation of the system has been built. The starlight sensor testing system consists of star simulator, star scene generation computer, sensor control computer. The starlight simulator is made up of power module, light source, LCD, display circuitry, optical collimator and computer interface. LCD and optical collimator are the key display component of starlight simulator.

Deformable mirror (DM) is a key component to the adaptive optics (AO) system. Its ability to fit the wavefront aberration determines the performance of the AO system. A wavefront sensorless adaptive optics (WFSless AO) system was used to investigate the fitting capability of a 97-element DM. We examined the fitting from the single order aberration of Zernike polynomial, combined aberration of Zernike polynomial and closed-loop correction, where the stochastic parallel gradient decent (SPGD) was used as close-loop correction algorithm. The results show that the 97-element DM has a good fitting ability to the first 3-54th single order of Zernike aberration. When the original wavefront RMS value was one wavelength, the residual wavefront aberration RMS was less than 0.4λ. The fitting to combine aberration of Zernike polynomial and closed-loop correction results based on the SPGD control algorithm show that the aberration was basically completely corrected when the wavefront aberration was small. When the wavefront aberration was relatively large, such as D/r0=20, the RMS of the residual wavefront aberration were smaller than 0.14λ (the initial RMS is 0.63λ). Above analysis results can provide theoretical basis and important reference for the practical application of the 97-element DM.

The unification and recognition of meteorological parameter is the key to achieve long-time scale climate monitor, which is solved by space radiation benchmark with high precision. A space-borne whiskbroom solar reflection spectrum radiation benchmark is proposed in this paper, and the standard value transmission is more simple and reliable, achieved by the pendulum sweep institution with high stability. Based on the pendulum sweep institution, the spectral response of transfer and sun spectral radiometer and hyper-spectral earth imager is calibrated in-flight. And the primary benchmark is space-borne cryogenic absolute radiometer, whose absolute measurement uncertainty is 0.02%. Besides, the absolute measurement uncertainty of transfer and sun spectral radiometer and hyper-spectral earth imager is analyzed respectively in this paper, and the absolute measurement uncertainty is 0.23% and 0.63%.

Tungsten disulfide (WS₂) nanosheets is a promising two-dimension (2D) material for offering lots opportunities in the development of new biological and chemical sensors and sensing strategies. Fiber SPR sensor is a powerful tool in the field of biology and chemistry. In this work, we simulated the effect of different tickness WS2 nanosheets on the fiber SPR sensor. The result show that, the SPR sensor perform best when WS2 nanosheets is 9.6 nm. Its refractive index sensitivity is 2018.4nm/RIU, the full width at half maximum is 151.4 nm, and the quality factor is 1.333.

Dynamic speckle analysis is a promising tool for inspection of speed of processes. It relies on highly sensitive of speckle phenomenon to micro-changes in the optical paths. The same phenomenon is a source of severe noise, which contaminates substantially the outcome of analysis when a pointwise processing is applied to correlated in time speckle patterns. We obtained improvement of quality of the two-dimensional activity map produced by the pointwise processing by illumination at two wavelengths in the red and green part of the spectrum and separate processing of the raw data acquired in the red and the green channels of a color camera used to capture the speckle patterns. Summation of the activity maps corresponding to the two channels results in narrower spread of fluctuations of the estimate chosen to describe the activity.

Based on the panoramic annular lens proposed by Professor Greguss, a new design of cemented compact two channel panoramic annular is introduced. The system consists of a triplet PAL, aperture stop and relay lens group. The triplet PAL have two field of views channels, 360°×60-99°and 360°×94-120°. The cemented surfaces are not only helpful to improve the freedom of design, but also correct the chromatic aberration.

The three-dimensional measuring system based on structured light has the advantages of propermeasuring range, high speed and non-contact measuring mode，and it is widely used in medical and manufacturing fields. The strip center extraction is one of the key steps in the line structured light vision measurement system. According to the line structure laser measurement model, the essence of the line structure measurement is to extract the pixel coordinates of the laser beam and substitute them into the measurement mathematical model formula to calculate the spatial coordinates of the measured points. Thus the accuracy and precision of laser strip pixel coordinate extraction directly affect the final calculation results. When the laser is projected onto the surface of the object to be measured, it is susceptible by the surface material of the object, ambient light and other factors, which may lead to speckle, uneven brightness of the light, wide range of light width variation and other problems. In this paper, an adaptive method for extracting light strips is proposed to solve the problems of speckle and wide width range of the light strips.

By exploiting those novel transport phenomena at nanoscale, the nanochannel system has shown electrically maneuverable conductance, suggesting the potential usage as neuromorphic devices. However, several critical features of biological synapses, i.e., the memorable and gradual conductance modulation, were seldom reported in the system. In this work by imposing room-temperature ion liquid (IL) and KCl solution into the two ends of nanochannel system, we demonstrate that this electrical manipulation of nanochannel conductance becomes nonvolatile and capable of mimicking the analog behaviors of synapses. The mechanism of gradual conductance tuning is identified as the voltage-induced movement of the interface between the immiscible RTIL and KCl solution according tofluorescencetechnique.

The paper is devoted to the problem of correct vergence in the mixed reality systems. There are two main types of mixed reality devices, these are optical see-through and video see-through mixed reality systems. They differ by the way how the device user observes the real-world environment: in the optical see-through mixed reality systems the real world is observed directly and as result the vergence and accommodation conflicts are absent while in the video see-through mixed reality systems there present both vergence and accommodation conflicts. The vergence conflict is caused by the fixed orientation of the device cameras that transmit the image of the real world, and the accommodation conflict is caused by the constancy of the focal length of optical systems that form the images of the real world on the human eye retina from the CCD matrices. This paper presents the research of the possibility to restore the correct convergence of a real-world image formed by video see-through mixed reality systems. The research shows how convergence can be correctly reconstructed using images captured by fixed cameras with parallel axes located at the front side of the mixed reality headset that form images for the left and right eyes. The resulting reconstructed images are almost free from any visual artifacts. Additionally, authors show how errors in scene depth map reconstruction affects the vergence restoration quality.

The two-step method using Hypothesis-Generation two steps to early detect the low-small-slow target, is based on the theory of multi-source detection fusion. The Hypothesis-Generation of the target information is built by the data set of multi-sensor. Hypothesis-Union distinguishing of the target information is based on the method of multi-source decision fusion, is realized by distributed decision feature fusion based on Bias minimum risk rule. The experimental results verify the feasibility and effectiveness of the method.

Deep ultraviolet (deep-UV) spectroscopy has been proved to be a promising technique for in-situ and real-time nutrient measurement, where key components, such as deuterium lamp light source with wide wavelength range from 190nm to 400nm, has been deployed. For water with multi-contaminations, experimental results indicated that the luminescence emission excited by the wide band light source lead to considerable measurement error. It is desired to develop a narrowband multi-wavelength ultraviolet (UV) light source for a more accurate measurement. However, rare research has been done towards such functional devices, such as wavelength filters and switches, in deep-UV band. Therefore, a novel deep-UV narrow-band filter, based on the deep-UV transparent rectangular single-mode optical waveguide and arrayed waveguide grating (AWG) structure, is proposed and designed in this manuscript. In order to reduce the loss and crosstalk, we optimize the decoupling distance and the number of array waveguide. In conclusion, this deep-UV multiwavelength narrow band-pass filter is designed to be single-channel input and 7-channel output with central wavelengths from 210nm to 240nm, channel spacing of 5nm. This device has -3dB bandwidth of 1.87nm, inter-channel cross-talk of - 23.80dB, and insertion loss of -4.25dB, device size of 40 mm (length) x 10 mm (width) x 2mm (thickness), having integratable interface with waveguide type optical switches and detectors.