This PDF file contains the front matter associated with SPIE Proceedings Volume 9298 including the Title Page, Copyright information, Table of Contents, Introduction, and Conference Committee listing.

The new progress of ground-based long-wave infrared remote sensing is presented. The LWIR hyperspectral imaging by using the windowing spatial and temporal modulation Fourier spectroscopy, and the results of outdoor ether gas detection, verify the features of LWIR hyperspectral imaging remote sensing and technical approach. It provides a new technical means for ground-based gas remote sensing.

Image quality assessment is an essential value judgement approach for many applications. Multi & hyper spectral imaging has more judging essentials than grey scale or RGB imaging and its image quality assessment job has to cover up all-around evaluating factors. This paper presents an integrating spectral imaging quality assessment project, in which spectral-based, radiometric-based and spatial-based statistical behavior for three hyperspectral imagers are jointly executed. Spectral response function is worked out based on discrete illumination images and its spectral performance is deduced according to its FWHM and spectral excursion value. Radiometric response ability of different spectral channel under both on-ground and airborne imaging condition is judged by SNR computing based upon local RMS extraction and statistics method. Spatial response evaluation of the spectral imaging instrument is worked out by MTF computing with slanted edge analysis method. Reported pioneering systemic work in hyperspectral imaging quality assessment is carried out with the help of several domestic dominating work units, which not only has significance in the development of on-ground and in-orbit instrument performance evaluation technique but also takes on reference value for index demonstration and design optimization for instrument development.

An acousto-optic tunable filter (AOTF) is an acousto-optic modulator. In this paper, the characteristics and overall design method of AOTF hyperspectral imaging system are proposed, which operates in visible or near infrared waveband (0.4-1.0um) and middle wave or long wave (3-5um and 8-12um). Compared with conventional dispersion element, the AOTF hyperspectral imaging system has a larger clear aperture because of the special characteristic of beam separation mode. In particularly, if the non-collinear design mode is used, the AOTF will have a larger diffraction aperture angle and is more suitable for the application in spectral imaging domain. The AOTF hyperspectral imaging spectrometer that operates in visible/near infrared waveband was developed by the non-collinear TeO2 crystal (8mm×8mm). All lights that are through TeO2 crystal in whole field of view (FOV angle is 5 degree) forms an imagines onto the staring focal plane array by Bragg diffraction. The diffraction wavelength of AOTF can be adjusted by the radio frequency signal. The three-dimensional data cube is composed of two-dimension of object space and wavelength in this way, and the graph and spectral are synthesized and implemented. The AOTF hyperspectral imaging spectrometer operating in visible/near infrared waveband is analyzed, and the detailed analysis data is also presented. The AOTF hyperspectral imaging test is studied and developed, and the analysis of data and the next developing advice is given. We also analyze the method about selection of material and technological design in middle wave/long wave infrared waveband of AOTF hyperspectral imaging system.

As the impact of the instrument internal error, external interference and other factors, the interferogram measured by Fourier transform spectrometer is asymmetric, result in the complex outcome after Fourier transform. Currently, most radiometric calibration method used for Fourier transform spectrometer is usually based on real spectrums, which is converted from the above complex spectrum by calculating magnitude value or make the phase correction first. Proceed from error sources and mechanisms of the Fourier transform spectrometer, we propose a multi-point radiometric calibration method based on complex spectral data to improve the processing efficiency and accuracy, which is obtained by the original interferogram via Fourier transform. We solving the instrument response function include linear gain and offset by complex spectrum above to calculate complex spectral radiance. Compared with the traditional method based on real spectrum, the present efficient method does not limited to real spectrum and the phase correction is not required. In this paper, we use BOMEM's MR304 Fourier transform infrared spectrometer and the DCN1000N3 blackbody made by HGH Infrared Systems to carry out the radiation calibration experiment in laboratory. The results show that, the amplitude of complex radiance spectrum obtained by this method has a high consistency with the theoretical value, while the extra imaginary spectrum is similar with the difference between results and theoretical value in absolute value and trends. It proved that, this multi-point radiometric calibration method by using the amplitude of complex spectral data is highly reliable; meanwhile, the imaginary spectrum can reflect the calibration error very well and offer a new technical approach for accuracy evaluation research.

Remote sensing instrument must be calibrated the optics reflectance of the instrument in vacuum conditions before lauched. To obtain the spectral reflectivity of less than 200 millimeter diameter optical element in vacuum, the reflectance of test system is constructed. The reflectivity of the test system is consisted of a light source, the Seya-Namioka vacuum visible monochromator, the sample room as the main structural and electronic system components. It describes how the optical systems and electronic are designed. The monochromator worked band is from 400nm to 780nm, spectral resolution is 0.5nm. Dual optical compensation method is used to eliminate the source of time drift, improve the measurement accuracy with phase-locked weak signal amplification method. The system used a lock-in amplifier according to the technique using the principle of coherent detection of the modulated optical signal which is multiplied with the reference signal processed, by using the optical integrator the signal will be smoothed sended to A / D converter. To ensure the precision measurement deteced, the phase-sensitive detector function can be adjustable. The output value is not more than 10mV before each measurement, so it can be ensured that the stability of the measured radiation spectrum is less than 1 percent. The reflectivity of the test system results is shown that the wavelength accuracy is 0.1nm, and the wavelength repeatability is 0.05nm, it can achievehigh-precision measurement of optical components under vacuum body.

Although the gas or liquid chromatography had been widely used into pesticide residues monitoring, some drawbacks such as time-consuming, complicated operation and especially the destructivity for samples were existed. To overcome the limits of destructive detection methods, the noninvasive detection method based on spectroscopy was used to detect the pesticide residues in this paper. To overcome low resolution and light-efficiency due to the drawbacks of the classical plane and holography concave gratings, a novel noninvasive spectrometer for pesticide residues monitor (PRM) based on volume holography transmission (VHT) grating was designed. Meanwhile, a custom-built splitting light system for PRM based on the VHT grating was developed. In addition, the linear charge coupled device (CCD) with combined data acquisition (DAQ) card and the virtual-PRM based on LabVIEW were respectively used as the spectral acquisition hardware and software-platform. Experimental results showed that the spectral resolution of this spectrometer reached 2nm, and the VHT grating’s diffraction efficiency was gotten via the simulation experiment.

With more than three decades of development, three-dimensional optical measurement technology has reached a mature stage in commercial applications, meanwhile new ones have continually arisen. Due to the development of Charge Coupled Device (CCD) array camera and digital projection technology, the applications of Phase Measurement Profilometry (PMP) become more and more broad. Among these, dual-frequency grating method has drawn many attentions because of its simplicity in principle and optical path, low requirement of equipment, high accuracy and level of automation comparing with other methods. The phase calculation is one of the key technologies in PMP. However, phase unwrapping algorithm in PMP is a difficult issue. A lot of new algorithm have been proposed, but neither one can solve all the problems, so how to set up new phase unwrapping algorithm becomes urgent. In this chapter, we systematically investigate the phase unwrapping method in dual-frequency grating method, and experimentally set up the system. To verify our method, we experimentally measure a three dimensional object which possesses complicated stair shapes on its surface. The results show that our dual-frequency grating method could achieve phase unwrapping without doing conventional phase unwrapping calculations, and it could also detect the detailed stair shapes on the surface of this three dimensional object automatically.

Tetragonal mercuric iodide, as a group of wide band gap semiconductors, has been widely investigation during most of the last half-century, applied on room-temperature X-ray and gamma-ray spectrometers. Up to the present, Mercuric iodide (HgI₂) is still thought to be one of the most outstanding vitality semiconductor materials because of its wide band gap, for which the device was required to be high resistivity, high atomic number, adequate mechanical strength, long carrier lifetimes and high mobility-lifetime produces. Now, HgI₂ polycrystalline films are being developed as a new detector technology for digital x-ray imaging. In this research, HgI₂ polycrystalline films with different surface areas of 1 and 36 cm² were grown by vapor sublimation method within a self-design growth furnace. XRD, SEM and J-V analysis were used to characterize the properties of these as-grown films. The results of XRD show that the ratio of (001) / (hkl) on all as-grown films is amount to be 90% for the area of 1 cm² films. Grain size of 1 cm² films was measured to be 120-150 μm. Their electrical resistivity were also determined to be about 10¹¹ Ω·cm operated at the bias voltage of ~100 V by I-V characteristic measurement. Utilizing the polycrystalline film with the area of 36 cm² deposited on TFT, we then prepared the direct image detector after capsulation for non-corrosive steel screw imaging. The results indicated that profile of screw was distinctly exhibited in digital x-ray imaging systems.

The onboard calibration unit is an important part of the space-borne imaging spectrometer and used for the onboard radiometric calibration and spectral calibration of the spectrometer. An imaging spectrometer used in marine satellite is given as an example and its onboard calibration unit is introduced. The onboard calibration unit is in the front of the optical path of the spectrometer, with the sun as the light source, the space qualified PTFE diffusers are used for the onboard radiometric calibration, and the space qualified PTFE diffuser doped with rare earth elements is used for the onboard spectral calibration. The components of the calibration unit are introduced. For the main radiometric calibration diffuser and the redundant radiometric calibration diffuser, the BDRF test results in component level are introduced. Considering the effects of the assembly error and the stray light after the assembly of the spectrometer, the BDRF test method of the radiometric calibration diffuser in system level is introduced. The test results of the directional hemispherical reflectance of the radiometric calibration diffusers and the spectral calibration diffuser are given and the wavelengths of the absorption peaks of the spectral calibration diffuser are obtained. According to the measurement signal of the spectrometer while the onboard spectral calibration, the wavelengths of the absorption peaks of the spectral calibration diffuser which can be used for the onboard spectral calibration are determined. The onboard calibration unit can satisfy the onboard calibration requirements of the spectrometer.

Hyperspectral image analysis method is widely used in all kinds of application including agriculture identification and forest investigation and atmospheric pollution monitoring. In order to accurately and steadily analyze hyperspectral image, considering the spectrum and spatial information which is provided by hyperspectral data together is necessary. The hyperspectral image has the characteristics of large amount of wave bands and information. Corresponding to the characteristics of hyperspectral image, a fast image fusion method that can fuse the hyperspectral image with high fidelity is studied and proposed in this paper. First of all, hyperspectral image is preprocessed before the morphological close operation. The close operation is used to extract wave band characteristic to reduce dimensionality of hyperspectral image. The spectral data is smoothed at the same time to avoid the discontinuity of the data by combination of spatial information and spectral information. On this basis, Mean-shift method is adopted to register key frames. Finally, the selected key frames by fused into one fusing image by the pyramid fusion method. The experiment results show that this method can fuse hyper spectral image in high quality. The fused image’s attributes is better than the original spectral images comparing to the spectral images and reach the objective of fusion.

Coded aperture snapshot spectral imager (CASSI) based on compressed sensing can capture a three-dimensional (3-D) data cube information in one snapshot without scanning, so it is a kind of novel spectral imaging technique with good prospects. In this paper, the data flow procession of two kind of CASSI were studied, which similarities and differences were depicted. The basic principle of the encoded representation of both spectral information and 2-D spatial information of a scene were presented. The numerical estimation techniques based on the compressive sensing theory were applied to reconstruct 3-D data cube.

Snapshot imaging spectropolarimetry is emerging as a powerful tool for mapping the spectral dependent state of polarization across most of scenarios (stable and variable), owing to its capability of real-time parallel acquisition. In this paper, two schema of snapshot full-Stokes imaging polarimeters (SFSIP) based on division-of-aperture polarimetry are presented firstly. In compliance with the definition of Stokes parameters, the first SFSIP consists of three Wollaston prisms with superior extinction ratio and simultaneously measures six polarimetric intensities (I₀, I₉₀, I45, I₁₃₅, I_L and I_R) of scene. However, the spatial resolution of each polarimetric image only occupy one-six of detector. To increase the spatial resolution, the second SFSIP comprises a optimal four-quadrant polarization array and a pyramid prism is used to simultaneously acquire four polarimetric intensities. Since the optimal four-quadrant polarization array consists of a uniform linear polarizer and four 132º retarders with different azimuth of fast axis, the signal-to-noise ratio for each of the recovered Stokes parameters will be balanced and enhanced. Finally, the four-quadrant polarization array and pyramid prism are integrated into a integral field spectroscopy to construct a snapshot full-Stokes imaging spectropolarimetry (SFSISP). It is used to map the spectral dependent full Stokes parameters across a scene in real time.

The instrument for spectral diffuse reflectance and color coordinate measurement has to be calibrated by a spectral reflectance standard, so as to obtain an absolute value. Normally, the value is traced to the primary color standard or diffuse reflectance standard. The integration sphere is one of the key components in the primary color standard of China, and the reflectance nouniformity of the sphere is the biggest systematic error source of the absolute measurement result. A novel uniformity analysis method is developed basing on scanning technique with CCD array spectrometer for reducing the effect of uniformity to the primary color standard measurement. The preliminary experiment shows that the effect of sphere nouniformity can be corrected basing on the scanning data of uniformity distribution.

The chemical element and mineral rock's abundance and distribution are the basic material of planetary geology evolution research ^[1], hence preterit detection for composition of Mars surface substance contains both elements sorts and mineral ingredients. This article introduced new ways to detect Mars elements and mineral components, Laser Induced Breakdown Spectroscopy (LIBS) and Raman Spectroscopy (RS) which have distinct advantages, such as work over a long distance, detect rapidly, accuratly and nondestructively. LIBS and RS both use laser excitation to shoot the substance of Mars exciting new wavelengths. The techniques of LIBS and RS in laboratory are mature, besides the technique of LIBS is being used in MSL (Chemcam) now and RS will be used in ExoMars. Comparing LIBS and RS's detection results with XRF and APXS, Mossbauer spectrometer, these existed Mars surface material detection instruments,and the Infrared spectrometer, Mid-IR, they have more accurate detection results. So LIBS and RS are competent for Mars surface substance detection instead of X-ray spectrometer and Mossbauer spectrometer which were already used in 'Viking 1' and 'Opportunity'. Only accurate detection results about Mars surface substance can lead to scientist's right analysis in inversing geological evolution of the planet.

The Gao Fen-1(GF-1) satellite with WFV sensors onboard was launched on April 26, 2013, as part of Gao Fen earth observing system. The Terra Moderate Resolution Imaging Spectroradiometer (MODIS) has been operational for more than a decade. With its high accuracy onboard calibration system, the data from MODIS has become a critical component of numerous applications. Cross-calibration between the sensors is critical to bring the measurements from different sensors to a common radiometric scale. Because of the differences in the spectral reflectance function (SRF), the measured physical quantities can be significantly different while observing the same target. This paper focuses on evaluation the radiometric calibration agreement between GF-1/WFV and Terra/MODIS using the near-simultaneous and cloud-free image pairs over Dun huang pseudo-invariant calibration site in the visible and near-infrared spectral range. The SRF differences of the analogous WFV and MODIS spectral bands provide the opportunity to explore, understand, quantify, and compensate for the measurement differences between these two sensors. Assuming that the ground target is spectrally and temporally stable, a typical reflectance spectrum over the Dun huang site obtained by in-situ measurements was used to compute spectral band adjustment factors (SBAF) for the cross-calibration. No BRDF correction was applied to reduce the seasonal oscillations since the analysis were restricted to only near-nadir images. The cross-calibration was initially performed by comparing the top-of-atmosphere (TOA) reflectance between the two sensors. WFV band 4 has the presence of the water vapor and oxygen absorption features which is absent from the corresponding MODIS band 2 which made the WFV measured TOA reflectance lower than the MODIS’s. Overall, the average percent differences were consistent to within 7%. The long-term cross-calibration results reflected that WFV sensor is stable since launch. Although the application of the techniques presented in this paper was focused on comparing near- nadir observations from WFV and MODIS reflective solar bands, it can be easily extended and applied to evaluate the differences between any other similar sensors.

The ZY-3 satellite plays an important role in agriculture, forestry, water conservancy, ecological environment, and so on since its successfully running. In order to achieve continuity, stability and reliability of the remote sensing data, and improve quantitative application level of the ZY-3 satellite data, an accurate sensor radiometric calibration is essential. Because ZY-3 satellite doesn’t have onboard calibration system, in-fight filed absolute radiometric calibration as a means to effective monitor the radiometric stability.This paper uses multi-day, multi-field at the Dunhuang test site to calibrate the ZY-3 multispectral sensor. The experiment obtained a synchronization measurement data on the August 18, 23 and 28, respectively. The two of ground surface were selected for measuring reflectance, which middling reflectance field (20%) and high reflectance field (40%). At the time of the ZY-3 overpass on the site, synchronous measure surface reflectance of ground targets, atmospheric optical characteristics parameters, such as atmospheric aerosol optical depth, atmospheric columnar water vapor content. Then use the radiative transfer model to estimate the top of atmosphere (TOA) radiance for MSS band. Radiometric calibration coefficient of MSS band was estimated by comparing the TOA radiance with average digital number of the MSS image. Based on multi-day, multi-field, and the real-time measurement at the Dunhuang site, radiometric calibration for ZY-3 MSS was successfully performed using reflectance-based method and calibration coefficients for MSS bands were obtained as well. According to contrast between in-fight calibration and the prelaunch, it was shown that the response of MSS changed at some extent after launch, especially band 1 and band 4. As a result, it was quite essential to update calibration coefficient timely and periodically in order to monitor the change of ZY-3 MSS better and to improve the quantitative application of MSS data as well.

The space-borne Fourier Transform Spectrometers (FTS) are widely used for atmospheric studies and planetary explorations. An adapted version of the classical Michelson interferometer have succeeded in several space missions, which utilized a rotating arm carrying a pair of cube corner retro-reflectors to produce a variable optical path difference (OPD), and a metrology laser source to generate the trigger signals. One characteristic of this kind of FTS is that it is highly sensitive to micro-vibration disturbances. However, a variety of mechanical disturbances are present as the satellite is in orbit, such as flying wheels, pointing mechanisms and cryocoolers. Therefore, this paper investigates the influence of micro-vibration on the space-borne FTS. Firstly, the interferogram of metrology laser under harmonic disturbances is analyzed. The results show that the zero crossings of interferogram shift periodically, and it gives rise to ghost lines in the retrieved spectra. The amplitudes of ghost lines increase rapidly with the increasing of micro-vibration levels. As to the system that employs the constant OPD sampling strategy, the effect of zero-crossing shifting is reduced significantly. Nevertheless, the time delays between the reference signal and the main signal acquisition are inevitable because of the electronic circuit. Thus, the effect of time delays on the interferogram and eventually on the spectra is simulated. The analysis suggests that the amplitudes of ghost line in spectra increase with the increasing of time delay intervals.

A new kind of polarization modulation is presented in this paper-sinusoidal polarization modulation. It can acquire the full linear polarization information of targets. The large advantage of this modulation is that it is very compact and with low mass and there is no moving parts in it. Moreover the demodulation algorithm is not only simple but also with high precision. It’s especially suitable for spaceborne atmosphere detecting sensor, providing a new kind of polarization modulation for it. After the incident lights passing through the modulator, it is modulated into sinusoidal with amplitude scaling with the degree of linear polarization and phase scaling with the angle of linear polarization. With a dedicated algorithm, the degree and angle of linear polarization can be acquired directly while traditional polarization modulation methods need I、Q、U、V parameters of the Stokes vector for further calculation. In this paper, theoretical and simulation analysis on spectral modulation are presented, the results of analysis point out the feasibility of this technology in theory.

Climate warming has become a serious problem facing all countries in the world, the impact of global climate change on the human environment subject to widespread international concern. In recent years, American and European countries invest a lot of manpower and resources to carry out the detection load of Atmospheric and Environmental Research, and the ultra-high spectral resolution capability is an important prerequisite for the realization of atmospheric trace constituents exact retrieved, the development of ultra-high spectral resolution load has become an important trend. This paper presents a new compact spectrometer for atmospheric and environmental exploration, which uses a narrow-band interference filter type, filter through different angles of incidence of the light beam spectral drift characteristics , to achieve ultra- fine spectral splitting . This spectrometer while achieving ultra-high spectral resolution , the structure of a compact camera with good engineering can be realized , and has broad application prospects.

Homography matrix is a matric representation of the projective relation between the space plane and its corresponding image plane in computer vision. It is widely used in visual metrology, camera calibration, 3D reconstruction and etc. Therefore, the accurate estimation of the homography matrix is significant. Here, the quantum-behaved particle swarm optimization method, which is global convergent, is first introduced into the estimation of homography matrix. When suited cost function is chosen, enough point correspondences can be utilized to search the optimal homography matrix, which can make the estimation accurately. For the purpose of evaluating the proposed method, simulations and experiments are conducted to confirm the feasibility and robustness. The points obtained from the deviated homography matrix are reprojected to the image plane to evaluate the accuracy. To compare with the proposed method, the Levenberg-Marquardt method, which is a typical iterative minimization method, is utilized to obtain the homography matrix. Simulations and experimental results show that the proposed method is reasonable, accurate, and with an excellent robustness. When 10 correspondences and 20 particles are utilized, the root mean square error of the re-projected points can reach about 0.019 mm. Furthermore, our proposed method is not related with the initialization and less correlated with the chosen cost function, which is the deficiency of the common estimation methods.

The principle of all types of spectrometers and structural features are studied , a new metrhod to design prism spectrometer system with wide field of view is proposed ,which is based on the offner struture .This type of spectrometer allows twice dispersion through the same prism.Compared with the traditional dispersive spectrometer system ,which can be greater dispersion width and smaller volume.Compared with the gating spectrometer ,which overcomes low diffracion efficiency,spectrum overlapping, ghosts, low SIR and other shortcomings. Finally, the design results were analyzed, and the image quality was evaluated.The results from the design anslysis showed the spectrometer has a smaller spectrum bending ,the MTF of the system at different wavelengths is close to the diffraction limit and the design meets the requirements .

Based on the tunable diode laser absorption tomography, gas concentration and temperature two-dimensional distribution reconstruction is realized using algebraic iterative reconstruction technique (ART). A measurement plan is proposed based on the beam splitting lens, and the corresponding beam arrangement is put forward. The beam splitting lenses are used in the plan to making one laser beam cross the measurement area repeatedly. Thus can raise the utilization ratio of laser beam and simplify the structure of measurement platform. A model for H2O vapor concentration and temperature distribution is assumed, and numerical simulation is utilized using two absorption transitions. The feasibility of the measurement plan is proved by the simulation experiment. The influences of initial beam angle, the number of beams and grids on the reconstructed results are analyzed numerically. A concept of phantom description method using in simulation experiments is proposed in order to getting closer to the real experiments. The phantom description method is used in the numerical simulation to evaluating concentration and temperature field reconstruction. Through this method, expected data is sampled from initial data, and reconstructed result is obtained by interpolation. The influence of random errors in projections on distribution reconstruction is also analyzed. The measurement plan can reconstruct the gas concentration and temperature distribution with a simplified measurement platform using beam splitting lenses. The feasibility of the phantom description method is also proved by the simulation experiment.

Medium Resolution Spectral Imager (MERSI) is a keystone instrument onboard Fengyun-3 (FY-3), the second generation of polar-orbiting meteorological satellites in China. There are three units currently in operation, in which FY- 3A and FY-3C were launched on May 27, 2008 and September 23, 2013, separately, in a sun-synchronous morning orbit with a local equator-crossing time of 10:30 AM in descending node, FY-3B was launched on November 5, 2010, in an afternoon orbit with an equator-crossing time of 1:30 PM in ascending node. FY-3 MERSI provides global coverage of top-of-atmosphere (TOA) radiances used for a broad range of scientific studies of the Earth’s system. Nineteen of the 20 MERSI spectral bands are reflective solar bands (RSBs) from 412 nm to 2130 nm, which cannot be absolutely calibrated onboard. The long-term on-orbit response changes are relatively large at visible spectral bands. The overall degradation for 412 nm of FY-3A MERSI is about 42% until the end of 2013. To implement the on-orbit calibration updates, a multisite calibration tracking method has been developed to monitor the RSB radiometric response variation, and a daily calibration updating model is presented. FY-3A/B MERSI is recalibrated using the daily calibration model, and the data quality is monitored using Aqua MODIS. This paper presents the recalibration of FY-3A/B MERSI RSBs accounting for the temporal variation of radiometric response, demonstrates the improvement to the MERSI radiometric data quality and retrieved products, and discusses issues that need further investigation.

Liquid lens of fast focusing is valuable to be researched for the application in instruments of miniature. According to many researchers achievement in this field, the fast focusing mechanism of liquid lens is firstly present. Then the oscillation modes of the liquid-solid coupling liquid lens in different capillary tube cases are analyzed in this paper. For better understanding of the fast focusing mechanism and its influencing factors, finite element models of the water droplet lens are set up in ANSYS, and the former four oscillation modes are solved to analyze the relative influencing relations. The work in this paper will lay a foundation for the further research on the liquid lens of fast focusing.

Spatial heterodyne spectroscopy (SHS) is a Fourier-transform spectroscopic technique with many advantages, such as high throughput, good robustness (no moving parts), and high resolving power. However, in the basic theory of SHS, the relationship between the wavenumber and the frequency of the interferogram is approximated to be linear. This approximation limits the spectral range of a spatial heterodyne spectrometer to a narrow band near the Littrow wavenumber. Several methods have been developed to extend the spectral range of the SHS. They use echelle gratings or tunable pilot mirrors to make a SHS instrument work at multiple narrow spectral bands near different Littrow wavenumbers. These solutions still utilize the linear relationship between the wavenumber and the frequency of the interferogram. But they need to separate different spectral bands, and this will increase the difficulty of post processing and the complexity of the SHS system. Here, we solve this problem from another perspective: making a SHS system work at one broad spectral band instead of multiple narrow spectral bands. As in a broad spectral range, the frequency of the interferogram will not be linear with respect to the wavenumber anymore. According to this non-linear relationship, we propose a broadband spectral inversion method based on the stationary phase theory. At first, we describe the principles and the basic characters of SHS. Then, the narrow band limitation is analyzed and the broadband spectral inversion method is elaborated. In the end, we present a parameter design example of the SHS system according to a given spectral range, and the effectiveness of this method is validated with a spectral simulation example. This broadband spectral inversion method can be applied to the existing SHS system without changing or inserting any moving components. This method retains the advantages of SHS and there is almost no increase in complexity for post processing.

Acousto-optic tunable filter (AOTF) is a novel device for spectrometer. The electronic tunability qualifies it with the most compelling advantages of higher wavelength scan rate over the conventional spectrometers that are mechanically tuned, and the feature of large angular aperture makes the AOTF particularly suitable in imaging applications. In this research, an AOTF-based near-infrared imaging spectrometer was developed. The spectrometer consists of a TeO2 AOTF module, a near-infrared imaging lens assembly, an AOTF controller, an InGaAs array detector, an image acquisition card, and a PC. A precisely designed optical wedge is placed at the emergent surface of the AOTF to deal with the inherent dispersion of the TeO2 that may degrade the spatial resolution. The direct digital synthesizer (DDS) techniques and the phase locked loop (PLL) techniques are combined for radio frequency (RF) signal synthesis. The PLL is driven by the DDS to take advantage of both their merits of high frequency resolution, high frequency scan rate and strong spurious signals resistance capability. All the functions relating to wavelength scan, image acquisition, processing, storge and display are controlled by the PC. Calibration results indicate that the spectral range is 898~1670 nm, the spectral resolution is 6.8 nm(@1064 nm), the wavelength separation between frames in the spectral image assembly is 1.0 nm, and the processing time of a single image is less than 1 ms if a TV camera with 640×512 detector is incorporated. A prototype device was assembled to test the capability of differentiating samples with similar appearances, and satisfactory results were achieved. By this device, the chemical compositions and the distribution information can be obtained simultaneously. This system has the most advantages of no moving parts, fast wavelength scan and strong vibration resistance. The proposed imaging spectrometer has a significant application prospect in the area of identification of camouflaged target from complex backgrounds. In addition, only the objective lens and its accessories are required to be replaced for its use in microscopic spectral imaging system, which may be popularized to a large number of other possible applications.

The airborne multispectral imaging fusion detection technology is proposed in this paper. In this design scheme, the airborne multispectral imaging system consists of the multispectral camera, the image processing unit, and the stabilized platform. The multispectral camera can operate in the spectral region from visible to near infrared waveband (0.4-1.0um), it has four same and independent imaging channels, and sixteen different typical wavelengths to be selected based on the different typical targets and background. The related experiments were tested by the airborne multispectral imaging system. In particularly, the camouflage targets were fused and detected in the different complex environment, such as the land vegetation background, the desert hot background and underwater. In the spectral region from 0.4 um to 1.0um, the three different characteristic wave from sixteen typical spectral are selected and combined according to different backgrounds and targets. The spectral image corresponding to the three characteristic wavelengths is resisted and fused by the image processing technology in real time, and the fusion video with typical target property is outputted. In these fusion images, the contrast of target and background is greatly increased. Experimental results confirm that the airborne multispectral imaging fusion detection technology can acquire multispectral fusion image with high contrast in real time, and has the ability of detecting and identification camouflage objects from complex background to targets underwater.

The multi-wave imaging spectrometer with high spectral resolution and high energy utilization is an essential tool to characterize the solar atmosphere. A novel method based on the aberrations correction and high grating efficiency is proposed to avoid the aberration and increase the temporal resolution. It is applied to design a dual band high spectral resolution imaging spectrometer based on New Vacuum Solar Telescope, it can simultaneously observe Hα 0.6563 um and CaII 0.8542 um lines, separately, improving the telescope observation efficiency. The ray tracing and optimization for the optical system are carried out with Zemax software. The results demonstrate that the wavefront RMS is roughly 0.06λ at 0.6563 um, and 0.04λ at 0.8542 um, within 3 arcmins field of view; The grating efficiency are all better than 70% in the range from 0.6 um to 1.1 um, which are equivalent to that of the fast imaging spectrograph (43%) installed in the New solar telescope at Big Bear Solar Observatory. The method is proved to be feasible, and can be used as a guidance to spectrometer design.

With the development of spectral imaging technology and polarization imaging technology, capturing the spectral profile and polarization signatures simultaneously will provide a wealth of evidence which helps to recognize the objects. Thus it has become a new trend in the area of remote sensing technology. In this paper, the existing polarization spectral imaging technologies are introduced and compared a new designing scheme to realize the miniaturized hyper-spectral and full-polarization imager are proposed, which is based on the combination of Acousto-Optic Tunable Filter (AOTF) and Liquid Crystal Variable Retarder (LCVR). The designing scheme is mainly composed of three modules: the spectral splitting module based on AOTF, the polarization control module based on LCVR and the image acquisition module based on Charge Coupled Device (CCD). The use of AOTF assists in achieving a hyper-spectral resolution higher than 5nm, as well as the abundant spectral information. While the LCVR enables us to gain multiple sets of polarization images of the target, after that, the polarization state of the target can be extracted according to Stokes vector and Mueller matrix. This designing scheme ensures a wide spectral range from 400nm to 2400nm by means of electronic tuning, and also achieves the hyper-spectral and full-polarization images of the target in rapid succession without mechanical moving parts. Besides, the development, testing, calibration and test scheme of the system are also introduced in the rest of the paper.

We validate the S-S method and the differential operator method through numerical simulations and experiments. Using a LED with a bandwidth of about 10nm as light source, we measure the spectral irradiance of the LED when the spectroradiometer bandwidth is 1nm and 5nm. The S-S method and the differential operator method act on experimental results to identify the efficiency of the methods. Through our analysis, the correction methods play significant roles in the spectral irradiance measurement. Especially, the correction methods are necessary when the light source has a narrow bandwidth feature.

Chlorophyll plays an important role in crop photosynthesis, and it is an indicator of crop growth and stress state. Estimation of leaf chlorophyll content of maize from remote sensing data was investigated using radiative transfer model inversion and wavelet analysis. Hyperspectral data of maize were measured in two natural fields using ASD field spectrometer, chlorophyll content was collected with a SPAD-502 chlorophyll meter. The bands between 350-1300nm spectra region were selected for the preprocessing, 10 spectra of each sampling point measurements of maize were averaged for smoothing. PROSPECT was used to generate very large spectral data sets, with which spectra region was set to 350-1300nm. The original hyperspectral of maize were applied wavelet transform with wavelet function of Haar, DB9, sym6, coif3, bior4.4, dmey to get transform coefficients, spectral reflectance of maize were obtained after the de-noising processing. Support vector machine was trained the training data set, in order to establish hyperspectral estimation model of chlorophyll content. A validation data set was established based on hyperspectral data, and the leaf chlorophyll content estimation model was applied to the validation data set to estimate leaf chlorophyll content of maize. The hyperspectral estimation model yielded results with a coefficient of determination of 0.8712 and a mean square error (MSE) of 76.1786. The results indicated that by decomposing leaf spectra, the wavelet analysis can be used to a fast and accurate method for estimations of chlorophyll content.

One fiber-fed high resolution echelle spectrograph was built for the one meter telescope atWeihai Observatory of Shandong University. It is used for exoplanet searching by radial velocity method and for stellar spectra analysis. One dimensional spectra extraction from the raw echelle data is researched in this paper. Flat field images with different exposure times were used to trace the order position accurately. The accurate background was fitted from each CCD image and it was subtracted from the raw image to correct the background and straylight. The intensity of each order decreases towards the order margin, and the lengths of order are different between the blue and red regions. The order tracing during the data reduction was investigated in this work. Accurate flux can be obtained after considering the effects of bad pixels, the curvature of each order and so on. One Interactive Data Language program for one dimensional spectra extraction was adopted and implemented to echelle data reduction for Weihai fiber-fed high resolution echelle spectra, and the results are illustrated here. The program is efficient and accurate for echelle data reduction. It can be adopted to reduce data taken by other instruments even the spectrographs in other fields, and it is very convenient for astronomers.

Comparing to the big-size scanning spectroradiometer, the compact and convenient fiber spectroradiometer is widely used in various kinds of fields, such as the remote sensing, aerospace monitoring, and solar irradiance measurement. High accuracy calibration should be made before the use, which involves the wavelength accuracy, the background environment noise, the nonlinear effect, the bandwidth, the stray light and et al. The wavelength lamp and tungsten lamp are frequently used to calibration the fiber spectroradiometer. The wavelength difference can be easily reduced through the software or calculation. However, the nonlinear effect and the bandwidth always can affect the measurement accuracy significantly.

Importance of extreme ultraviolet (EUV) and far ultraviolet (FUV) calibration is growing fast as vacuum ultraviolet payloads are wildly used in national space plan. A calibration device is established especially for the requirement of EUV and FUV metrology and measurement. Spectral radiation and detector relative spectral response at EUV and FUV wavelengths can be calibrated with accuracy of 26% and 20%, respectively. The setup of the device, theoretical model and value retroactive method are introduced and measurement of detector relative spectral response from 30 nm to 200 nm is presented in this paper. The calibration device plays an important role in national space research.

The SBIR Model 13145 Infrared Target Projectors ( The following abbreviation Evaluation Unit ) used for characterizing the performances of infrared imaging system. Test items: SiTF, MTF, NETD, MRTD, MDTD, NPS. Infrared target projectors includes two area blackbodies, a 12 position target wheel, all reflective collimator. It provide high spatial frequency differential targets, Precision differential targets imaged by infrared imaging system. And by photoelectricity convert on simulate signal or digital signal. Applications software (IR Windows ^TM 2001) evaluate characterizing the performances of infrared imaging system. With regards to as a whole calibration, first differently calibration for distributed component , According to calibration specification for area blackbody to calibration area blackbody, by means of to amend error factor to calibration of all reflective collimator, radiance calibration of an infrared target projectors using the SR5000 spectral radiometer, and to analyze systematic error. With regards to as parameter of infrared imaging system, need to integrate evaluation method. According to regulation with 《GJB2340-1995 General specification for military thermal imaging sets 》testing parameters of infrared imaging system, the results compare with results from Optical Calibration Testing Laboratory . As a goal to real calibration performances of the Evaluation Unit.

A novel dual-band static Fourier transform imaging spectrometer was designed, which was the spatio-temporally modulated imaging Fourier transform spectrometer based on Sagnac interferometer. The approach represented a simplification and mass reduction over the traditional approach. It could obtain two-dimensional spatial images and one dimensional spectral image in two bands simultaneously. The two bands was separated through a dichroic prism and imaging in two detectors. one band was the visible and near infrared band, with the spectral range 400nm-1000nm and spectral resolution 187.5 wave numbers; the other was the short wave infrared band, with the spectral range 1000nm- 2500nm and spectral resolution 150 wave numbers. To reduce the size of the Interferometer, a high aperture compression ratio telescope system was designed before. The optical aperture was compressed to 1/10, and the volume of interferometer was reduced to 1/1000. For the convenience of engineering implementation, the telescope was composed of two no-aberration object lens: fore-lens and Collimating lens. The two band imaging spectrometers shared the primary lens and the second lens of the fore-lens and use their own collimating lens, interferometers and Fourier transform lens. The collimating lens and the Fourier transform lens of each spectrometer could be designed to the same structural style and parameters. The both spectrometers had a focal length of 1000mm, F number of 5, FOV(field of view) of 1°. Moreover, both image qualities were close to the diffraction limit, the distortion was less than 2%. The advantage of the instrument was that dual band spectral image could be acquired at the same time and the interferometer was miniaturized extremely in the case of unchanged technical indicators.

Fourier transform spectrometer without input slit is an emerging technology for spectral imaging. It has the advantages of high spatial resolution and high radiation throughput compared to the similar device with input slit. A near-infrared (NIR) Fourier transform spectrometer using Sagnac interferometer is presented and discussed in this paper. This system is composed of a Sagnac interferometer used as a lateral shearing splitter, an objective and a NIR camera. The principle of the system is presented including the discuss of its main characteristics and the optical layout of the Sagnac interferometer. Then the main technical features are discussed, such as the sample of the optical path difference (OPD). A experimental device is set up and presented that is used for two proven experiments. Some spectral images are reconstructed from 1050nm to 1720nm and proves the feasibility of the proposed system for NIR spectral imaging.

For large aperture telescope, we place the significance on the jitter of the wave front parameters when we make effort to obtain better image. We investigate the power spectral density for charactering the optical jitter for large telescope as stochastic sequence. Limited by frequency domian property, the universal used metric, and root mean square of wave front error (RMS WFE) cannot provide adequate information .This paper provides a complete and easy-to-use approach to the specification of mid-and-high frequency aberration of the wave front. Additionally, we apply welch method to the calculation of the power spectral density to achieve the accuracy result without much noise involved. Lastly, we verify this theory by the analysis of a laser system.

Laser communicator equipment, designed for advanced optical communication, with a large capacity communication, good encryption and lightweight structures, etc., has a wide range of applications. As for the special transmission characteristic of optical communication, laser phase in the transmission path should be accurate, and less thermal deformation for the optical parts is required in the working process, so the laser communicator equipment has a high level requirement for temperature. Large power units cooling, outer two-dimensional rotating units, temperature control for rotating cable, and high temperature stability and equality, bring a challenge for thermal design. Using structure –electric-thermo-optical integration technology, active and passive thermal control methods are adopt in thermal design for laser communicator equipment: heat-conducted plate and heat pipe were adopted for heat transfer of high heat-flux parts, a new passive and active thermal control method to solve cable cryogenic problems, and high precision temperature control methods were applied for key parts. In-orbit data were analyzed, and the results prove the thermal design correct, and bring a way to thermal control for the equipment with high heat flux and running parts.

Surface irregularity of optical elements is one of the errors caused in manufacturing process. The primary aberration caused by surface irregularity is astigmatism which can hardly be removed in traditional alignment method. An alignment method by rotating the lens for compensating the deterioration of the image quality caused by surface irregularity is put forward in the paper, and the mathematical model of the method is established. The calculation of the rotate angle is described in detail. A numerical simulation of the method has been performed for a four-lens precision optical system to verify the ability and accuracy of the method. The results show that the astigmatism of the optical system caused by the surface irregularity can completely be removed, and the image quality can be improved effectively. The method is especially suitable for the optical system which demands a very high image quality.

The wavefront error of large telescopes requires to be measured to check the system quality and also estimate the misalignment of the telescope optics including the primary, the secondary and so on. It is usually realized by a focal plane interferometer and an autocollimator flat (ACF) of the same aperture with the telescope. However, it is challenging for meter class telescopes due to high cost and technological challenges in producing the large ACF. Subaperture test with a smaller ACF is hence proposed in combination with advanced stitching algorithms. Major error sources include the surface error of the ACF, misalignment of the ACF and measurement noises. Different error sources have different impacts on the wavefront error. Basically the surface error of the ACF behaves like systematic error and the astigmatism will be cumulated and enlarged if the azimuth of subapertures remains fixed. It is difficult to accurately calibrate the ACF because it suffers considerable deformation induced by gravity or mechanical clamping force. Therefore a selfcalibrated stitching algorithm is employed to separate the ACF surface error from the subaperture wavefront error. We suggest the ACF be rotated around the optical axis of the telescope for subaperture test. The algorithm is also able to correct the subaperture tip-tilt based on the overlapping consistency. Since all subaperture measurements are obtained in the same imaging plane, lateral shift of the subapertures is always known and the real overlapping points can be recognized in this plane. Therefore lateral positioning error of subapertures has no impact on the stitched wavefront. In contrast, the angular positioning error changes the azimuth of the ACF and finally changes the systematic error. We propose an angularly uneven layout of subapertures to minimize the stitching error, which is very different from our knowledge. At last, measurement noises could never be corrected but be suppressed by means of averaging and environmental control. We simulate the performance of the stitching algorithm dealing with surface error and misalignment of the ACF, and noise suppression, which provides guidelines to optomechanical design of the stitching test system.

The properties and developments of materials for large aperture space mirrors, which are pursued for high-resolution earth observation and deep space exploration, are summarized in this paper. All these materials were classified into several kinds depend on their substance and performance. Their advantages and disadvantages in manufacturing large aperture space mirrors were discussed; especially their fabrication, optical machining and application. The trends of development of materials for large space mirrors are overviewed.

The multi-channel scanning imager is one of the main payloads of a Geostationary earth orbit satellite of China, which observe multi spectrum from earth. Passive thermal control was applied to decrease temperature rise when solar intrusion at midnight, and heat compensation was made to decrease thermal fluctuation in one orbit. Effort was focused on the scanning mechanism for its relatively strict temperature gradient requirement. In order to validate thermal control scheme, thermal balance experiment scheme was planned. Considering the complexity of solar heat flux into sunshade, solar simulator was used to precisely simulate the heat flux variation. Limited to the dimension of vacuum chamber and solar simulator lamp, only the flux into sunshade was simulated by solar simulator, and other parts was simulated by electrical heaters. The solar illuminated region was analysed in order to keep the total heat flux correct. Detailed test process was figured out to carry out two kinds of heat flux simulation. Date were acquired and compared to thermal analysis. Based on experiment condition, thermal model was constructed and modified. From analysis of all the effecting factors, it is find that thermal contact resistance between heatpipes and heat dissipating plate can largely effect the temperature of scanning mechanism. Thermal model of scanning mechanism was detailly constructed including features effecting heat flux absorption and temperature distribution. After modification, the prediction ability of thermal model was enhanced. And optimization of thermal design was made to decrease temperature level and gradient of scanning mechanism. Thermal analyse was done to estimate the optimization, and its effectiveness was validated.

When polishing and modifying the large aperture flat by the traditional polishing tools, people usually test it by a spherical mirror as a standard surface which been called the Ritchey-Common method, that not only can break through the limitation of the aperture, but also can achieve high precision wave front if the surface of the standard mirror is perfect. However, when doing ultrahigh precision modifying by the modern polishing equipment such as: ion beam polishing, this testing method cannot meet the need of the high precision location, because of the error caused by the nonlinear transformation of the coordinate, the testing result usually cannot been very exactly developed point to point, that restrained the polishing accuracy. Here the error has been studied in order to exactly developing the testing result. At first, in principle, the Ritchey- Common testing path has been analyzed in detail. Secondly, the point to point transfer equation has been deduced, and some feature points have been chosen to help analyze the relationship between the object surface and the image result. Then a program has been written according to the deduced equation, by which the image can be well developed. Finally the error has been compared by using different developing methods in the experiment. The study can solve the nonlinear point to point transfer and location problem caused by the Ritchey-Common testing method, so when manufacturing the large aperture flat, the Ritchey-Common testing method can be used in the ultrahigh precision polishing.

Laser ranging technology can directly measure the distance between space targets and ground stations with the highest measurement precision and will play an irreplaceable role in orbit check and calibrating microwave measurement system. The precise orbit determination and accurate catalogue of space targets can also be realized by laser ranging with multi-stations. Among space targets, most of ones are inactive targets and space debris, which should be paid the great attentions for the safety of active spacecrafts. Because of laser diffuse reflection from the surface of targets, laser ranging to space debris has the characteristics of wide coverage and weak strength of laser echoes, even though the powerful laser system is applied. In order to increase the receiving ability of laser echoes, the large aperture telescope should be adopted. As well known, some disadvantages for one set of large aperture telescope, technical development difficulty and system running and maintenance complexity, will limit its flexible applications. The multi-receiving telescopes technology in laser ranging to space targets is put forward to realize the equivalent receiving ability produced by one larger aperture telescope by way of using multi-receiving telescopes, with the advantages of flexibility and maintenance. The theoretical analysis of the feasibility and key technologies of multi-receiving telescopes technology in laser ranging to space targets are presented in this paper. The experimental measurement system based on the 60cm SLR system and 1.56m astronomical telescopes with a distance of about 50m is established to provide the platform for researching on the multi-receiving telescopes technology. The laser ranging experiments to satellites equipped with retro-reflectors are successfully performed by using the above experimental system and verify the technical feasibility to increase the ability of echo detection. And the multi-receiving telescopes technology will become a novel effective way to improve the detection ability of laser ranging to space debris.

The high precision off-axis asphere mirrors are quite usefull in the modern sapce optical system.in this paper, the ion beam figuring is researched to accomplish the final surface accuracy. Firstly, The IBF machine we used is introduced simplely. The correction method for the distortion in off-axis mirror interference measurement is studied. Beacasue of the curve shape of the off-axis mirror, the changing of the removal function was analyzed simply. In order to testify the reaserch, a 1100mm×800mm off-axis aspheric mirror is finished by ion beam figuring. After 2 times polishing, the surface error was corrected to RMS 9nm in full aperture and achieved 6.3nm in sub- aperture.

Space infrared sensor must be assembled on a small satellite platform, so its whole mass and structure dimensions are strictly restricted by the satellite platform. The mechanical structure must be compacted, light, handy and reliable. Task of space infrared sensor structure system is to integrate each parts of system and provide a stable and reliable work platform for the whole body. The transfer functions of flexible object and base are analyzed by using mechanical impedance method and compared with stiffness models. It indicates that space infrared sensor must be considered the flexible body influence for transfer function on some certain conditions. Using second order Krylov method expresses multi-DOF flexible substructure, which combines with modal synthesis method to model and analyze two substructures connecting with springs and dampers. Compared with direct FEM arithmetic, it can improve the calculation efficiency and handle variable-rate stiffness and damping model or complex stiffness model of flexible connection, which is cannot do for common commercial FEM software.

This paper proposes a low-cost unimorph deformable mirror (DM) driven by positive voltages for ocular adaptive optics (AO). The DM consists of an inner actuators array and an outer ring actuator. The inner actuators array is used to correct aberrations, while the outer ring actuator is used to generate an overall defocus bias. The measurement results show that the maximum peak to valley defocus deformation is more than 14 μm. The DM has a satisfactory correction capability for up to the fifth order Zernike mode aberrations. Furthermore, a sample of 200 ocular wavefronts was simulated using a statistical model developed by Thibos. After correction with the developed DM, most of the simulated eyes achieved the diffraction-limited performance. These experimental and simulation results indicate that this DM is satisfactory for ocular applications.

In order to verify the effect of stray light elimination design, the detailed stray light analysis of one modified large aperture optical telescope using TracePro is described in this paper. Firstly, the sources of stray light in optical telescope and the influence of stray light on optical telescope are introduced. Then, the principle of stray light analysis using TracePro is presented. The solid model, surface properties and light paths of the modified large aperture optical telescope are determined. Ray splitting and importance sampling are adopted to ensure the calculation accuracy and reduce the time consumption. The Point Source Normalized Irradiance Transmittance (PSNIT) curve of the system is plotted. It shows the PSNITs are less than 10^-12 when off-axis angles are larger than 30°, which satisfies the requirement of the system. Finally, the several special fields of stray light control are discussed.

Intensity correlation imaging(ICI) method can obtain high resolution image with ground-based low precision mirrors, in the imaging process, phase retrieval algorithm should be used to reconstituted the object’s image. But the algorithm now used(such as hybrid input-output algorithm) is sensitive to noise and easy to stagnate. However the signal-to-noise ratio of intensity interferometry is low especially in imaging astronomical objects. In this paper, we build the mathematical model of phase retrieval and simplified it into a constrained optimization problem of a multi-dimensional function. New error function was designed by noise distribution and prior information using regularization method. The simulation results show that the regularization method can improve the performance of phase retrieval algorithm and get better image especially in low SNR condition

In order to choose enclosure for the next generation telescopes, numerical simulation method was used. Firstly, the telescope, two general kinds of enclosures structure and the external flow field model were established, Then CFD(Computational Fluid Dynamics) technology was used to analyze the wind speed, static pressure, turbulence kinetic energy distribution and eddy around the telescope, when the telescope at two different pointing gestures and the external wind speed at 10m/s. The simulation results showed that when the telescope adapt the retractable enclosure, the wind speed of the main optical path between 6.1 m/s and 9.3 m/s, and the average static pressure (gauge pressure) on the primary mirror between 42.9268 Pa and 37.5579 Pa, however when telescope adapt the hemispherical enclosure, the wind speed of the main optical path between 3.4 m/s and 6.8 m/s, the average static pressure (gauge pressure) on the primary mirror between 12.1387 Pa and 11.105 Pa. Although the wind resistance of the retractable enclosure was lower than the hemispherical enclosure, no eddy generated near the main optical path, it provided the telescope a uniform flow field and ensured the quality of the image of a star. So the retractable enclosure would have better performance than the hemispherical enclosure.

Ultraviolet (UV) radiation of 200nm-300nm waveband from the sun is absorbed by atmosphere, which is often referred to the solar-blind region of the solar spectrum. Solar-blind characteristics of this waveband have important application value in forest-fire prevention, UV security communication, UV corona detection and other aspects. Especially in military fields such as missile warning, the application of solar-blind waveband has developed very rapidly, which is receiving more and more attention recently. In this paper, ZEMAX software is used to design an optical system of solar-blind UV target receiver with waveband 240nm-280nm, with which UV target signal can be detected. The optional materials are very few for UV optical systems to choose from, in which only CaF2 and JGS1 are commonly used. Various aberrations are not easy to be corrected. So it is very difficult to design a good UV system. Besides, doublet or triplet cannot be used in UV optical system considering possible cracking for different thermal expansion coefficients of different materials. So the doublet in initial structure is separated for this reason. During the optimization process, an aspheric surface is used to correct the aberrations. But this surface is removed before the design is finished to save production cost and enhance the precision of fabrication and test, which still keeps the image quality meeting the usage requirements. What we care for is the converging condition for different field of view from the far object on image plane. So this is an energy system. Spot diagram is taken as the evaluation criterion of image quality. The system is composed of 6 lenses with field of view (FOV) 31 degrees. In the final design results, the root mean square (RMS) radius for marginal FOV is less than 6.3 microns, while the value is only 4 microns for zero FOV. Point Spread Function and diffraction encircled energy diagram within the maximum FOV confirms the good performance of system further.

With the aperture of telescope becoming larger, the mass of primary mirror and other relevant structures will become heavier as well. Therefore, lighting weight for large space-based telescope is necessary. This paper purposed a method based on Neural Network aims to build a math model for primary mirror of large space-based telescope, which can reduce weight of the telescope and smaller mirror deformation caused by gravity release effectively. In the meantime, it can also improve stiffness of structure and reduce thermal strain caused by on orbit temperature variation effectively. The model describes the relationship between the structure of primary mirror of large space-based telescope and corresponding deformation, and describes the optical performance of mirror by using Zernike Polynomial. To optimize the structure of primary mirror lightweight, we take the deformation of mirror and its optical performance into consideration. To apply the structures parameters and its corresponding deformations to Neural Network training, we use the combination samples of different mirror lightweight structure parameters and corresponding deformation which caused by gravity release and thermal condition. Finally, by taking advantage of the Neural Network model to optimize the primary mirror lightweight of 1-meter rectangle space-based telescope, which can make the RMS 0.024λ (λ=632.8nm)and areal density under 15kg/m². This method combines existing results and numerical simulation to establish numerical model based on Neural Network method. Research results can be applied to same processes of designing, analyzing, and processing of large space-based telescope directly.

Joint transform correlator (JTC) is quite useful for pattern recognition in many fields, which can realize automatic real-time recognition of target in cluttered background with high precision. For military application, JTC can also be applied for thermo target recognition especially at night. To make JTC recognize thermo targets, an infrared telephoto lens is designed in this paper. Long focal length and short tube length are required for this usage. So the structure of a positive lens group and a negative lens group are adopted. Besides, the effective focal length and relative aperture should be large enough to ensure the distant targets can be detected with adequate illumination. In this paper, the working waveband of adopted infrared CCD detector is 8-12μm. According to Nyquist law, the characteristic frequency of the system is 14lp/mm. The optional materials are very few for infrared optical systems, in which only several kinds of materials such as Germanium, ZnSe, ZnS are commonly used. Various aberrations are not easy to be corrected. So it is very difficult to design a good infrared optical system. Besides, doublet or triplet should be avoided to be used in infrared optical system considering possible cracking for different thermal expansion coefficients of different infrared materials. The original configuration is composed of three lenses. After optimization, the image quality can get limit diffraction. The root mean square (RMS) radii of three fields are 6.754μm, 7.301μm and 12.158μm respectively. They are all less than the Airy spot diameter 48.8μm. Wavefront aberration at 0.707 field of view (FOV) is only 0.1wavelength. After adjusting the radius to surface templates, setting tolerances and giving element drawings, this system has been fabricated successfully. Optical experimental results of infrared target recognition using JTC are given in this paper. The correlation peaks can be detected and located easily, which confirms the good image quality of the designed infrared telephoto lens.

Ultraviolet (UV) radiation of 200nm-300nm waveband from the sun is absorbed by atmosphere, which is often referred to the solar-blind region of the solar spectrum. Solar-blind characteristics of this waveband have important application value, especially in military fields. The application of solar-blind waveband has developed very rapidly, which is receiving more and more attention. Sometimes, to test the performance of a UV optical system, a standard solar-blind UV target simulator is needed as the UV light source. In this paper, an optical system of a solar-blind UV target simulator is designed with waveband 240nm-280nm. To simulate a far UV target, the focal length of this UV optical system needs to be long. Besides, different field of view (FOV) of the system should meet aplanatic condition. The optional materials are very few for UV optical systems, in which only CaF2 and JGS1 are commonly used. Various aberrations are difficult to be corrected. To save production cost and enhance the precision of fabrication and test, aspheric surfaces and binary elements are not adopted in the system. Moreover, doublet or triplet cannot be used in UV optical system considering possible cracking for different thermal expansion coefficients of different materials. After optimization, the system is composed of 4 lenses with focal length 500mm. MTF curves of different FOV coincide together. The maximum RMS radius of the optimized system has almost the same size as Airy disk, which proves the good image quality after system optimization. The aplanatic condition is met very well in this system. In the spot diagram, root mean square (RMS) radius changes from 3 microns to 3.6 microns, which has similar size with Airy disk and meets aplanatic condition very well. This optical system of solar-blind UV target simulator also has relatively loose tolerance data, which can prove the system is designed in an optimal state.

Based on a 979-actuator adaptive optics system, this paper analyzes the different performance of iterative wavefront reconstruction algorithms. Under the condition of dynamic wavefront errors, the iteration number, storage space and the number of multiplication of steepest descent method, conjugate gradient method and G-S iterative method are studied. The steepest descent method and conjugate gradient method need smaller storage space. Both the G-S iterative method and the conjugate gradient method converge faster than steepest descent method, while the latter takes the least number of multiplication. Finally, the optimal iterative algorithm is selected considering storage space, iteration numbers and the number of multiplication.

The theoretical model of thermal-steady-state anisotropic Tm:YLF crystal was built based on the practical operation condition. Integral transformation was used to get the analytical expression of the distribution of temperature in Tm crystal and thermal focal length. Matlab was used to simulate the influence of pump power density, crystal length and doping density to the distribution of temperature and thermal focal length. The results showed that under the invariant pumping power density and crystal length, the temperature rise and nonuniformity of thermal distortion are intensified by the increase of doping density which leads to a worse thermal effect. Under the invariant pumping power and doping density, the temperature rise and nonuniformity of thermal distortion are weaken by the modest increase of crystal length which leads to a good thermal condition. When the product of crystal length and doping concentration is a constant value, the thermal focal length keeps basic consistent. Furthermore, the simulated results are that when the dual-pumped power is 60W and waist radius is 430μm, the thermal focal length of 12mm, 3at.% doped which perpendicular and parallel to c axis are 184mm and 261mm respectively, and the thermal focal length of 12mm, 3.5at.% doped which perpendicular and parallel to c axis are 171mm and 243mm respectively. The results in this paper provide theoretical basis for thermal compensation and cavity design of dual-pumped Tm:YLF laser, meanwhile, the model built can be used to analyze other anisotropic crystals.

Speckle imaging techniques are effective post-processing methods to eliminate atmospheric perturbations on the imaging of space objects, in which speckle interferometry and bispectrum methods are usually used to estimate the magnitude and phase spectrum of the objects separately. The spectral ratio technique used in this paper is convenient and efficient to evaluate r0, which is crucial for calibrating the speckle transfer function in the magnitude estimation. It is shown that power spectrum, the second moment of the magnitude spectrum, needs bias removal whereas bispectrum processing does not. Reconstructed images from the observed data of binary stars and Jupiter are presented.

CCD60, developed by e2v technologies, is a 128x128 pixel frame-transfer back-illuminated sensor using the EMCCD technology. This kind of detector has some attractive characteristics, such as high frame rate, low noise and high quantum efficiency. So, it is suitable for Adaptive Optical Wave Front Sensor (AO WFS) applications. However, the performance of this detector is strongly depended on its temperature. In order to achieve high multiplication gain and low dark current noise, CCD60 should be cooled under -45℃. For this reason, we had designed a cooling system to cool down the CCD60 detector base on thermoelectric cooler. Detail of the design, thermal analysis and the cooling experiment are presented in this paper. The performance of multiplication gain after cooling had been tested too. The result of cooling experiment shows that the thermoelectric cooler can cool the CCD to below -60 °C under air cooled operation and an air temperature of 20 °C. The multiplication gain test tell us the multiplication gain of CCD60 can exceed 500 times on -60℃.

As the improvement of imaging resolution of earth observation satellite, the optical axis disturbance (referred as LOS jitter) introduced by satellite moving components, such as reaction wheel, CMG, cryocooler etc., become one of the important factors that limits the imaging quality. So far as we know, there are several methods to control the frequency and amplitude of LOS jitter, such as satellite attitude control system (ACS), vibration isolator, image stabilization system etc. Each method has its own application range: ACS can only response to low frequency disturbance to about one tenth Hz, but it can deal with large amplitude disturbance; vibration isolator usually attenuates LOS jitter amplitude in high frequency, but may magnify jitter in low frequency; image stabilization can stabilize the LOS jitter in low-mid frequency, but limited to small amplitude. So it is necessary to use several methods together to insure the imaging quality. Here comes the question, how to design and allocate the system specification reasonably to satisfy the requirement of imaging and to make it possible for these methods to realize. This paper presents a new optimization method based on the frequency domain for the satellite imaging chain related with optical axis jitter. First describe the performance of each link of the imaging chain in the frequency domain, then through the calculation of image MTF using LOS jitter PSD, build up the relation between the imaging quality and the frequency performance of mixed links, then combine the frequency performance and the spectral decomposition method, the relation between each link and system imaging quality can be built. Then Based on this method, the requirement of imaging quality related to each link can be allocate and optimize quantitatively, which is essential for the design of imaging chain related with optical axis jitter.

With the urgent need for the development of high data rate transmission of information and high-resolution observation techniques, research on high-speed laser communications networking technologies is imminent. This article analyzes the basic requirements of space laser communication links and the technical difficulties and achieve in the network need to be solved. The optical principle of the networking were proposed, studied technical solutions of a laser can be used for communication between multiple targets simultaneously, designed with the rotating parabolic antenna to the base of the optical multi-mirror stitching structure, as well as transmitting and receiving relay optical system with APT system, a new technical approach was provided for the space laser communication link Networking. According to the parabolic features, for the incident light firing at the direction of focus, the reflected light is parallel to the optical axis. But the energy efficiency is low for this type of surfaces, only small portion of the energy can be received. So it is designed to form the multi-mirror mosaic structure with parabolic base. The normal of each mirror is perpendicular to the tangent of the paraboloid. The size, shape, number and the combination way of mirrors are designed and optimized according to the orbit position and number. Each mirror is controlled to perform the movement in the horizontal and azimuth directions, in this way the antenna has certain stability and light deflection. With this antenna, communication can be realized for objects in different orientations at the same time for 360° in horizontal direction and big field of view in azimuth direction.Finally, it prospected the application foreground.

A modern 2-m telescope is in comissioning phase at Wendelstein Observatory since late 2013. In order to make full use of good seeing conditions in Wendelstein, many measures were taken to reduce the image aberration to get the best image quality. Due to its fast primary mirror, the telescope image quality depends critically on the secondary mirror alignment. Thus a scheme of quick and accurate alignment of the secondary mirror is desired for the telescope system. We will utilize a Shack-Hartmann wavefront sensor (SHS) to optimize the alignment for a basically well aligned telescope system. The principle of the image aberration measurement using SHS is shortly re-introduced with this paper. Merit function regression method can be used to align the secondary mirror of the telescope system using Zernike coefficients derived from the reconstructed wavefront. The principle of merit function regression method is described in this paper. Optical and mechanical layout of this telescope alignment system is also shown. A temperature stabilized box for SHS was designed to keep the wavefront measurement precision of a commercial SHS system in the harsh conditions of an observatory site. Mechanical design and temperature control system of the temperature stabilized box are also illustrated. The deviation of the temperature is within 0.04 degree from the first test of the temperature stabilization experiment, which is good enough to decrease the wavefront measurement error produced by environmental temperature variation.

The shape, size and material of grinding tool not only affect the machining accuracy, but also the machining efficiency in the process of Computer Controlled Grinding. The hardness of the SiC aspheric mirror, the misfit of grinding tool and the work-piece also emphasize the importance of grinding tool optimization. By means of analyzing the misfit property of grinding tool and aspheric optic theoretically, as well as the wear character and the process of the grinding tool experimentally, this manuscript establishes the rule of grinding tool optimization satisfying different machining objective. Based on this, the adopted grinding tool was optimized in the grinding process of SiC off-axis aspheric (634mm×560mm). The simulation provide reasonable grinding tool for the off-axis aspheric grinding, and good results (large amount material removal and edge error figuring) are obtained when the optimized grinding tool are applied. Both of the simulations and experiments demonstrate the feasibility and correctness of the grinding tool optimization method.

In this paper we propose a projective LED low-beam headlamp of motorbikes. An ellipsoidal reflector is used to collect light emitting from the LED source. A baffle plate is located in the focal point of the ellipsoidal reflector to form the cut-off line.Then the light is redistributed by an optical lens. We set the measuring screen as an semi-circular zone and divide it into many small lattices, divide the spatial angle of the LED source into many parts and make relationships between them. According to the conservation of energy and Snell law, the lens is generated by freeform optics design method. Then the optical system is simulated by Monte Carlo method using ASAP software. Light pattern of simulation could meet the national standard. The low-beam headlamp is finally fabricated and assembled into a physical object. Experiment results can fully comply with regulations GB5948-1998.

Pupil filtering is a widely used super-resolving technique. This technique utilizes one or more diffractive superresolution elements (DSEs) to break the diffraction limit. This paper focused on the tolerance analysis of DSEs. Although the analysis in this paper was based on a specific super-resolution system, it was sufficient to demonstrate our efforts and make some conclusions. Generally, two types of tolerances have been taken into consideration. One is DSE's position tolerance. The other is the tolerance of DSE's phase transmittance. With the presented method, it is able to evaluate the influence of DSE tolerances on a super-resolution optical system, and thus to guide practical fabrication.

Tunable Fabry–Pérot (F-P) based narrow band filter has been widely used in large solar telescope, which is utilized to isolate an arbitrary wavelength that we are interested in by adjusting the cavity length. However, it is difficult to guarantee that the mirror scan strictly parallel. As a result, the observations of the solar telescope would be affected. Here, we proposed a method to extract the tilt information of the scanning mirror. At first, the interferogram is obtained on the outer surface of the F-P interferometer. Then an interferogram of double-path is obtained from the multi-beam fringe pattern, which contains the tilt information of the moving mirror. Finally, the Radon transform is used in processing the interferogram to extract the tilted plane. Good results come out of the simulation of this method. It has high accuracy and high stability. It can provide feedback information to the closed-loop control system, and guide the tilt correction.