Minority carrier diffusion length is a key parameter of material quality and gives an indication of diode performance. It is also one important parameter when considering the increase of the effective optical sensitive area caused by the lateral diffusion and the crosstalk between individual detectors on a focal plane array (FPA). In this paper, we perform diffusion length measurements with two methods on short wavelength infrared (SWIR) HgCdTe photovoltaic devices. One method is based on the different behaviors of electrons and holes in a variation magnetic field B and their effects on the saturation current density J0. The other method is an optical characterization technique called Laser Beam Induced Current (LBIC). The results were in good agreement with each other.

In this paper, low frequency noise has been investigated in SWIR HgCdTe photodiodes from 4Hz to 3.2 KHz at different reverse bias. At low frequency the noise mainly consists of flicker noise and generation recombination (g-r) noise while at high frequency thermal noise is the dominant component. The flicker noise current is proportional to the detector current at small reverse bias, and the Hooge parameter α_H of the device is evaluated. In addition, the low frequency noise at 100mV reverse bias measured from 250-300K are reported. The fluctuation time constant of g-r noise is extracted by fitting the curve of the low frequency noise, and the trap thermal activation energy of the deep level is obtained from the relation of τ and temperature.

Cadmium zinc telluride (Cd_1-yZn_yTe) single crystals are important material for infrared detectors fabricating process and radiation detectors. Cd_1-yZn_yTe crystal wafers are widely used as substrate to grow epitaxial layers of mercury cadmium telluride (Hg_1-xCd_xTe) that is an important process for infrared detectors with high resolution. Especially, Cd_1-yZn_yTe with small concentrations (y=0.03~0.04) is favored for this purpose since the lattice constant of Cd_1-yZn_yTe (y=0.03~0.04) is close to that of Hg_0.8Cd_0.2Te, which has a bandgap corresponding to 10 micron. These applications impose certain requirements on the Cd_1-yZn_yTe crystals. Impurity concentrations should be low, especially for Cu, which can readily diffuse into the epitaxial layer and alter its electrical properties. Dislocation etch pit density should be low, typically no more than 1×10⁵ cm^-2. Infrared transmission should be high, usually greater than 60%, from 2.5 to 20 μm. Precipitates, visible as dark spots in infrared transmission microscopy, should be no larger than 10μm in diameter, and their density no higher than 0.5×10⁵~1×10⁵ cm^-2. This paper reports results on how these requirements can be met by our research and development works in Kunming institute of physics mainly through controlling the cadmium atmosphere pressure in the quartz ampoule.

The HgCdTe photovoltaic detectors passivated by single ZnS layer and dual (CdTe+ZnS) layers were fabricated in same wafer. The fabricated devices were characterized by measurements of the diode dark I-V characteristics and low-frequency noise. The dual-layer passivated diodes showed the better performance compared to the single layer passivated diodes, and modeling of diode dark current mechanisms indicated that the performance of the diodes passivated by single ZnS were found to be strongly affected by tunneling current related to the surface defects, By the analysis of X-ray reciprocal space maps, It was found the Q_y scan direction broadening of HgCdTe epitaxial layer passivated by ZnS was wider after passivation, which confirmed the existence of defects in the surface of HgCdTe epitaxial layer passivated by ZnS.

This study is concerned with electrical shock effect on performance of the n-type HgCdTe photoconductive detector with a composition of x≈0.225 in order to improve the reliability under this certain situation. Ideally, responsivity of HgCdTe photoconductive detector is proportional to its bias current. Since there are a number of thermal interfaces between the detector and the cooling reservoir, the temperature of HgCdTe chip will rise and the response will decrease with the increase of bias current. The detectors we used in the experiment were divided into two groups, one for room temperature experiment and the other for liquid nitrogen temperature experiment. A large pulse bias current was used to give the detector "an electrical shock". After the shock the resistance, responsivity and detectivity of detectors were measured at normal conditions. For the group of room temperature, the experiment results show that the detector responsivity will decrease under a 200mW pulse electric-power and the resistance will change under 400mW. When the pulse electric-power reaches 2000mW the detector will be burned out. But for the group of liquid nitrogen temperature experiment the detector responsivity will change under a 90mW pulse electric-power and the resistance will change under 290mW. A 550mW pulse electric-power will burn the detector out. Analysis with one-dimension approximation model was given, which showed that epoxy used between the interfaces was essential for increasing the reliability of HgCdTe detector.

In order to obtain more detection channels and simpler structure, bi-color optical route and bi-color detection can be used in modern remote imagers. But this technology can not come into reality without bi-color thin film filters. To design such a filter is not easy since it needs a much larger number of thin film layers. In this paper the author discusses different design methods and points out that the periodical symmetrical stack is more practical to design such a filter. Numerical design example for 3.5~4.0 micrometer and 8.0~9.0 micrometer channels is given with two often-used infrared coating materials ZnS and Ge. As made in other filter design, different optimization processes were made to obtain more ideal result. Practical fabrication of this filter was made to test the numerical design result with a box-type vacuum coater. Experimental results show that the peak transmittance of both channels exceeds 70%, with a cut-off transmittance less than 1% from visible region to near 11 micrometer which meets approximately the requirements of remote imagers.

Hybrid barium strontium titanate (BST) ferroelctric detectors still provide the basis for the majority of uncooled infrared systems being produced today. Considering the complexity of the hybrid BST detector fabrication process, monolithic BST thin-film dielectric bolometers allure the researchers. For the micro-bridge thermal isolation structure, the performances of single pixel of BST thin-film dielectric bolometer mode of uncooled infrared focal plane arrays (IRFPA) are computed by thermal diffusion equation.

Pixel level on-focal-plane analog to digital conversion(ADC) promises many advantages including high performance and low power consumption. In this paper we argue that CMOS technology scaling will make pixel level ADC increasingly popular. Then we introduce four existing techniques for pixel level ADC. The first is an over sampling technique which uses a one bit first order sigma delta modulator for each pixel to directly convert photo charge to bits, consists of an integrator, a one bit DAC and a clocked comparator. The second technique is Nyquist rate multi-channel-bit-serial(MCBS) ADC. The technique uses special successive comparisons to convert the pixel voltage to bits. The third technique bases on a simple and robust pulse frequency modulation(PFM) scheme that can convert the photocurrent of photodetectors to proportional pulse frequency. The fourth is a software-controlled ADC, which utilize a algorithm, takes a desired photocurrent quantization scale to output bits. Each pixel contains a programmable digital processing element which directly controls the behavior of the photo detector with software. These four techniques are analyzed and compared according to their advantages, disadvantages and suitable application area. Finally we mention our current and future works with one of these techniques.

This paper presents the recent progress on the study of device processings at multilayer HgCdTe film for integrated two-color (SWIR/MWIR) n-p-P-P-N detector arrays. The four-layer p-P-P-N heterostructures Hg_1-xCd_xTe film needed to achieve two color detector arrays was grown by molecular beam epitaxy (MBE) on (211)B oriented GaAs substrates. The secondary ion mass spectroscopy (SIMS) data for the HgCdTe film was obtained. The p-type layer on top of a thin P-type potential barrier layer and the SWIR P-on-N homojunction photodiode formed in-situ during MBE growth using indium impurity doping was processed into the MWIR planar photodiode by selective B⁺-implantation. The preliminary 256×1 linear arrays of SWIR/MWIR HgCdTe two-color FPAs detector were then achieved by mesa isolation, side-wall passivation and contact metallization. At 78K, the average R0A values of SWIR and MWIR are 3.852×10⁵ Wcm² and 3.015×10² Wcm², and the average peak detectivities D_λp^* are 1.57×10¹¹cmHz^1/2/W and 5.63×10¹⁰ cmHz^1/2/W respectively. The SWIR photodiode cut-off wavelength is 3.04μm and the MWIR photodiode cut-off wavelength is 5.74μm, quite consistent with the initial device design. The SWIR response spectrum of the two-color detector with a distinct fall-off at shorter wavelength regime was discussed especially.

As far as cooled staring arrays are concerned, InfraRed (IR) detectors with a 320x256 format are produced at mass production level since the end of the nineties but the request for miniaturization and affordability is more and more important for IR systems. To answer these requirements, SOFRADIR has taken its HgCdTe (Mercury Cadmium Telluride/ MCT) material and process as well as its hybridization technology to the next even more advanced level of sophistication and is now offering large format detectors with graduated levels of performances regarding pitch size and cryogenics. For Mid Wave (MW) applications a TV (640x480 or 640x512) format MCT with 15 μm pixel pitch is offered allowing the integration of highly miniaturized cryogenics including the use of quarter Watts micro-coolers and dedicated to compact systems or to the upgrade of existing systems using TV/4 (320x240) format. This new 15 μm pitch MCT TV format exhibits a very small size cryogenics in order to fit the system requirements of miniaturization and cost reduction. For Long Wave (LW) applications, 288x4 TDI scanning arrays are offered with compact cryogenics and take advantage of the use of the same advanced cryogenics developments. Finally, as far as long wave staring arrays are concerned a 25 μm pitch 384x288 HgCdTe detector has been developed allowing the use of 0.5W micro cooler with miniaturized cryogenics. The characteristics and performances of these new IR detectors are presented in this paper.

For the limit of its lifetime, the Stirling cooler is operated on the intermittent mode in satellite in some cases. Thus such cryogenic semiconductor components as HgCdTe mid or long wavelength infrared (IR) detectors are subjected to thousands of repeated thermal cycles from below -173°C to room temperature. Therefore, a series of experiments focused on quality, performance and reliability are essential in order to satisfy the reasonable requirements. Accordingly, a feasible thermal cycle screening system is put forward. And a vast experimental data show that thermal cycle tests play the most effective role in the environment stress screen (ESS). In this paper, we introduce the system to help to study the main failure mechanisms and improve the performance of the semiconductor components. Such main failure mechanisms as solder-ball invalidation encountered commonly in the detector modules, which is due to the large thermal expansion coefficient mismatch among different materials. The thermal cycle system is based on the principle of heat exchange. We expect HgCdTe IR detectors be cooled to lower than -173°C and heated to room temperature in a few minutes. Above all, we simulate the heating and cooling system through finite element method (FEM). As a result, the computations reveal that the IR detectors can be heated and cooled at a higher rate than expected. A consequent design of the entire system is founded on the simulation. At last, we adjust the mechanical structure of heat exchange system to the adaptive state to accomplish the ESS. The thermal cycle screening system includes an autocontrol part and a test part. The autocontrol part is adopted to realize the heat exchange between IR detectors and the environment, and the test one to inspect the temperature and electrical parameters of these detectors. And at least four IR detector samples can be screened at one time.

Uncooled infrared focal plane arrays are being developed for a wide range of thermal imaging applications. Developments are focused on the improvement of their sensitivity enabling the possibility of reducing the pixel pitch in order to decrease the total system size and weight by using smaller optics. We present the ULIS second generation technology used for producing 320 x 240 (384 x 288) and 160 x 120 IRFPA with a pixel pitch of 35 µm. This enhanced technology was developed by CEA / LETI and has been transferred to ULIS in 2003. The device architecture will be described. This device is well adapted to high volume military applications (i.e. thermal weapons sight, enhanced driver vision) and commercial applications (i.e. predictive maintenance, firefighting, thermography, medical,...) where specifications are the result of a trade-off between pixel pitch, performance and system weight. We have developed for these devices low cost packages. IRFPA electro-optical characterization is presented.

With the development of high performance focal plane arrays (FPAs) which provide very good sensitivity, operability, and excellent image quality, FPAs are applicable to wide-field-of-view, long range surveillance and targeting missions. However, many applications, like space- and air-borne surveillance telescopes, emphasize wide field of view (FOV) over resolution, permitted the most rapid survey of the entire field of regard. This is typically limited by large, complex, and costly corrector optics to flatten the wavefront. An alternative approach is to design a curved focal plane to alleviate the designing burden of optical system. Conventional approach is by the way of providing the ability to produce FPAs with a specified degree of curvature while preserving required electro-optical characteristics. After brief introduction normal FPAs based novel method in virtue of spot-to-curved-line converter, the paper presents the dynamic performance analysis of this Curved focal plane compensation imaging system in detail.

The Laboratoire Infrarouge (LIR) of the Laboratoire d'Electronique, de Technologie et d'Instrumentation (LETI) has been involved in the development of microbolometers for several years. Therefore a first generation of a high performance technology made from amorphous silicon thermometer has been transferred to ULIS in 2000 and a second generation has been transferred in 2003 for being able to manufacture small pixel pitch uncooled IRFPA. LETI is still working to improve uncooled IRFPA and two principal research orientations are currently studied. First LETI improves performances of low cost detectors for both military and civil applications. Secondly LETI develops a very low cost packaging technology for high volume applications like automotive. Since packaging operations represent today the most significant part of detectors price, LETI has studied an original on-chip packaging structure less expensive than wafer level packaging structure. Il means, that after standard collective technology of bolometers, the process continues with microcaps manufacturing over the microbolometer or over the array of microbolometers. It requires specific technological developments in order to build this micro-caps and the main difficulty consists in closing hermetically micro-events manufactured previously in the caps, while maintaining expected vacuum around the detector. Another difficulty consists in choosing window cap materials and thickness to minimize IR absorption that is crucial for our application. LETI will present status of its developments of this innovating technology and SEM views from the first lab test device.

The great achievements were achieved in the manufacturing of uncooled microbolometer infrared focal plane arrays(UFPA). By this technique infrared system can be made in the formation of small volume, light weight, low price and being portable. It promotes greatly the utilization of infrared system in many fields. The main disadvantage of UFPA is non-uniformity. Despite non-uniformity of UFPA has been greatly improved, non-uniformity still restricts the performance of uncooled infrared system. In this paper, the attention is focused on the technology and methods measuring the non-uniformity of UFPA. The system that can measure the non-uniformity of UFPA and evaluate the image processing algorithms is developed. The measurement system consists of blackbody, infrared optics, control units, processing circuit, high-speed A/D converter, computer and software. To obtain the output signals of UFPA, the drive circuit and control circuit of thermoelectric stabilizer(TEC) of UFPA are developed. In the drive circuit, the CPLD device is employed to insure a small size circuit. In the TEC circuit, a kind of highly integrated and cost-effective, high-effiency, switch-mode driver is used to insure temperature stability of 0.01°C. The system is used to measure non-uniformity of microbolometer detectors which are produced by ULIS company. It can also present the evaluation of algorithm. The results are given and analyzed.

We introduce a multi-point and real-time method for corrects the nonuniformity of uncooled IRFPA. First of all, all pixels are classified to different kinds according to their response characteristics in the system. Then we figure out the correction parameter of each subsection of every kind response curve. Not only the correction precision of this method is higher than two-point correction algorithms, but also it solves the difficult, such as needing lots of correction parameter, the system will be very complex and hard to realize, etc. of common multi-point method. It has marked merits as follow: high correction precision, easy to realize and the real-time characteristic.

In this article, the system of real-time infrared image process based DSP technology was introduced. The real-time infrared image processing consists of detection, recognition and tracking. Based on DSP hardware platform and the way of temporal image differential with motion compensated, the paper describes the image process card principle, the arithmetic of object detection, DSP C6202 design and technology realize. Finally, we do some experiments outfield to verify the real-time infrared image process system. Infrared image of airplane be provided in tracking experiment.

In real-time system, the Infrared Focal Plane Array (IRFPA) should be compensated in traditional method of two-point temperature non-uniformity correction (NUC) before system was used every time, which make the system complex. Based on discussion of traditional two-point temperature NUC algorithm, Two-point temperature NUC based on least mean square (LMS) algorithm was proposed in the paper. In the view of the LMS algorithm theory, the correction gain and offset coefficients were iterated one by one during image processing, so that the expected correction result were obtained in little time. At the same time, the correction and coefficients iteration processes were completed in FPGA and DSP respectively, and make the arithmetic structure simple. The simplified structure, low cost and out-door suitable operation-systems are the merits of the system.

A 320×240-uncooled-microbolometer-based signal processing circuit for infrared focal-plane arrays is presented, and the software designs of this circuit system are also discussed in details. This signal processing circuit comprises such devices as FPGA, D/A, A/D, SRAM, Flash, DSP, etc., among which, FPGA is the crucial part, which realizing the generation of drive signals for infrared focal-plane, nonuniformity correction, image enhancement and video composition. The device of DSP, mainly offering auxiliary functions, carries out communication with PC and loads data when power-up. The phase locked loops (PLL) is used to generate high-quality clocks with low phase dithering and multiple clocks are to used satisfy the demands of focal-plane arrays, A/D, D/A and FPGA. The alternate structure is used to read or write SRAM in order to avoid the contradiction between different modules. FIFO embedded in FPGA not only makes full use of the resources of FPGA but acts as the channel between different modules which have different-speed clocks. What's more, working conditions, working process, physical design and management of the circuit are discussed. In software designing, all the function modules realized by FPGA and DSP devices, which are mentioned in the previous part, are discussed explicitly. Particularly to the nonuniformity correction module, the pipeline structure is designed to improve the working frequency and the ability to realize more complex algorithm.

There has been much interest in the field of laser radar (ladar) owing to its high-resolution three-dimensional imagery. However, the coherent ladar images are affected badly by speckle, which is a multiplicative noise and has the statistical features of the negative exponential density. In the paper, the morphological filter based on the parametric edge detection is introduced in detail. Then, this detector and the ratio edge detector are compared with the conventional LOG (Laplacian of Gaussian) operator and Canny operator. At last, the edge detection results for coherent laser radar image are obtained. The experimental results show that the morphological filter based on parametric edge detection and the ratio edge detector are better than other algorithms for coherent ladar image, and the morphological filter based on the parametric edge detection is the best algorithm in this paper.

A novel algorithm, which is based on creating the variance image of original image, for infrared image enhancement is proposed. Ordinary spatial filtering is powerful of reducing the noise of image, but it also reduces the contrast of image. Compared with spatial filtering, variance image not only reduces the noise but also enhances the image. In this paper, we combine the variance image and histogram equalization to enhance the infrared image blurred by random noise. The experimental results show the algorithm based on creating variance image is simple and effective, it can be widely used in infrared image enhancement.

Images acquired from an infrared (IR) sensor typically suffer from poor spatial resolution due to the finite size of the lens that makes up the imaging system and the consequent imposition of the underlying diffraction limits. The lost frequency components beyond the diffraction-limited cutoff make the obtained images blur. Currently there are one kind of image processing schemes referred to as super-resolution algorithms available for solving of this problem, including Bayesian analysis methods, set theoretic methods, and Fourier domain techniques. But an estimate of the blur model parameters is essential in these methods. If incorrect blur parameters are chosen then the super-resolution results will be wrong. This work presents an original solution to the blur parameters identification problem in infrared image super-resolution. A back-propagation(BP) neural network is used for the blur parameters identification. In this method, we consider the modulation transfer function (MTF) of an infrared system as a Gaussian type. Mathematical analysis shows that using back-propagation neural network it is possible to identify the parameters of the Gaussian blur. After blur parameters identification, the image can be restored using several kinds of methods. We choose the Poisson-MAP super-resolution algorithm with Markov constraint(MPMAP) as our restoration method. Experimental results demonstrate that the performance of the MPMAP method using the blur parameters identified by our neural network is superior to other blind image restoration methods.

A modular Infrared simulation test system has been developed for laboratory testing of a kind of UUT with Infrared (IR) sensors. This paper mainly focuses on the software development for the system. The software for the system is divided into two parts, i.e. the main control computer software and image generation computer software. The main control computer software is responsible for the software & hardware control, setup of the simulation test and the analysis of the simulation results. The image generation computer is responsible for the generation of static and dynamic IR image, the control of moving entities in IR simulation scene and the calculation of simulation data. The two computers use network communication to transfer commands and data. The modules and implementation methods for the software are described.

In this paper, one close-loop tracking system was presented and the simulated moving target was made. The system consists of detector, rotating stage, high-speed image processor, central control Unit, servo-control system, etc. Based on the TI DSP, the high-speed image processing system is constructed. And the simulated moving target used for the close-loop tracking system was made.

We have developed a new dynamic infrared scene projector using the Texas Instruments Digital Micromirror Device (DMD) which has been modified to project images which are suitable for testing sensor and seekers operating in the UV, visible, and IR wavebands. This paper provides an overview of the design and performance of the projection system, as well as example imagery from prototype projector systems. The dynamic IR scene contains 1024×768 pixels and can be updated at a rate of approximately 85 Hz.

A method of detectivity D*(T, f ) conversion for infrared detector at different target temperatures , is introduced in this paper. And it has been proved, the D* value only relate to the relative spectral distribution of radiant source and detector, but not relate to their absolutely spectral distribution.

The Bench for Infrared Detectors (BIRD 210) has been designed for testing IRFPA detectors up to 1024 x 1024 pixels. It is also suitable for single element detectors. The detectors are required to be equipped with their coolers (Stirling or thermo electrics) and cooler electronics.

In the spectrum range of middle wave infrared region (MWIR) and the long wave infrared region (LWIR) radiation, the infrared spectral imaging technology is far from mature in comparison with its counterpart in visible region because infrared radiation is relative weak, the corresponding solid-state detectors and dispersive elements are extremely expensive. The paper reports a novel configuration that exploits the abundant chromatic aberration of binary optical lens to create a dual band infrared imaging imager. The design method of spectrum-dividing systems is presented for infrared imaging spectrometer. The system was analysed and evaluated by optical design software ZEMAX, theoretical formulas were then established. The practical design shows that the system has the very simple optical design that enables a very low cost lightweight robust dual band infrared imaging spectrometer.

A special airborne hyperspectral remote sensing flight test for Push Broom Hypersectral Imager (PHI) were executed in Huangpujiang river region of Shanghai in Oct, 2003, and the water sampling and water quality parameters analyzing experiments were carried out almost in-phrase. Linear retrieval models were built with the water quality parameters and field measuring spectral reflectivity, and these models were applied to retrieve the water quality from images. Seven water quality parameters were retrieved from the images, and the classification maps of five of these parameters were made from PHI images of Wusong mouth where the Huangpujiang River entered the Yangtze River, and the concentration of Suspended Sediments concentration and Turbidity degree were also retrieved, comparing with the actual measurement results, the retrieved classifications were reliable with the error less than one type, and the retrieved results of the suspended sediment and turbidity degree were accordance with the actually measured results.

An innovative Fourier Transform hyperspectral imaging system based on reflective optics is currently being studied. It can record both spatial images and spectral information of a sample instantaneously. Substantial properties of the sample can be elucidated from such images. Compared to classical Imaging Spectrometer using lenses and prisms, the significant characteristic of this system is that it only uses reflective mirrors and just one beam splitter. Such structure will help to largely avoid the limitation of spectral range and the refraction non-homogenize both of which affect the quality of imaging. Therefore, the noticeable advantages of this system are high signal-to-noise ratio, high spatial and spectral resolution, large spectral bandwidth, high throughput, non-chromatic aberration and very compact optical structure in which just one imaging system could applicable to a rather wide spectral bandwidth. This project includes both theoretical analysis and development of an experimental instrument. With the instrument, the images that contain one-dimensional spatial image and another dimensional interferogram are already collected. The data processing system could transform the interferogram of each scene to its spectral information. The typical experimental results are given in this paper.

Dedicated experiments were made to clarify interference of the oil vapor, establish the quantitative analysis model and test its effectiveness in analyzing transformer fault gases with Fourier Transform Infrared. Nicolet Nexus 670 FTIR Spectrometer with a 2-meter vacuumable gas cell is used to collect and examine the spectra of the top gap gases and pyrolytic products of the transformer oil and no additional interference other than diagnostic gases were found. Standard gas samples of CH₄, CO and CO₂ are diluted with super pure nitrogen via mass control flowmeters to get samples with different concentrations dynamically. Spectra of the diluted samples are collected, analyzed and used as calibration standards to measure other samples. It is shown that the absorbance of the spectra can be calculated in height of the peak or in area under the peak and they vary with concentrations in approximate linearity, yet the former is more active and the latter is more passive to be saturated. Repeated measurements say the relative error of the established model is below 4% and typical measured concentrations are 537μL/L for methane and 57μL/L for monoxide.

Near-infrared spectroscopy is a fairly powerful recent but well-established tool that can be used to study and measure biological and chemical concentrations, and the water is an important portion of organism and chemical reagent. Near-infrared (NIR) spectroscopic studies of water have long been a subject of keen interest from various points-of-view. The importance of the NIR spectrum of water stems from the fact that the frequencies and intensities of bands due to water alter with changes in the strength of hydrogen bonds and hydration. The NIR absorbance spectroscopy of water and the single-beam of the water were measured over a temperature range of 10-80°C at increments of 5°C and a spectroscopic range of 1-2.5μm. It had been validated that positions of water absorption bands centered at 6900cm^-1 depend heavily on temperature effects. Temperatures can also influence the bands of the water molecules combinations and overtones. The trend of water absorbance spectroscopy's changing is discussed detailed in this paper. Especially the variety of the band amplitude and the shift tendency in peak position are all presented in this paper. At the same time, the spectroscopies that are collected with different parameter setup of the spectrograph during the temperature change are obtained. Partial least squares (PLS) calibration models were constructed at sixteen separate temperatures.

The MRC (Minimum resolvable contrast) is used to evaluate the performance of watched directly imaging system. The MRC mode is deduced on the basis of human visual system and signal detection. The model which involves the influence of spatial and temporal factors reflects the limited sensitivity in different object illuminance and contrast. The simulation result shows: The calculated limited sensitivity by MRC model is consistent with the reality of system. It is a more perfect model for evaluating the performance of low- light level imaging system.

Grassland is an important vegetation type in China and plays an important role in human subsistence and development. Remote sensing technology is an efficient means of grassland ecological monitoring, but at present we lack of systemic study on spectral characteristics of dominant grassland types in the west of China, which restricts the application research of grassland remote sensing. The key is in-depth and systemic study of ground spectrum of grasslands. So we collected ground spectrum of dominant natural grasslands every 10 days from May to October in 2003 using GER 1500 spectrometer in the region around Qinghai lake, an important pasturing area in the north of China. Using these data the paper systemically studies the change rule of green peak, red edge, and other feature parameters in relation to spectrum waveform, as well as that of commonly used vegetation index within grasslands' growth period. Then the paper elementarily analyzes the ability to classify grassland using spectrum data at different scale, and delivers corresponding methods of classification on the basis of feature extraction and feature transformation experiments.

Geostationary satellites play a key role in observing the spatial and temporal variations in surface and atmospheric features, which are important for monitoring short-term weather. While limited in spatial resolution compared to low-earth orbiting satellites, geostationary platform provides a significant advantage. The primary advantage is the ability to characterize the radiance by obtaining numerous views of a specific earth location for any time of day. This allows the production of a composite image to monitor short-term weather better. It will be shown that only 14% of days were missed in retrials, compared to the likely miss rate of 60-70% of a polar orbiting satellite. Mie theory is applied to calculate scattering characteristics of dust particles, and analyze dust channel selection of meteorological satellite. It can be seen that the visible channel is the primary channel available for dust aerosol observation. Also, the shortwave channel has some sensitivity to aerosols. Therefore, optically thick dust can have significant effect on infrared radiation. The radiative temperature of dust in shortwave infrared and longwave infrared is different also because emissivity is the function of wavelength. We compare the emissivity of rock, soils, vegetation, water and ice in shortwave and longwave channel, referring to the paper of John W. Salisbury. It can be seen that the different emissivity of soils is the most obvious. We apply difference of two wave bands to distinguish dust storm. The practical difference image proves the point. Geostationary orbit satellite is main tool in distinguishing short time weather phenomena such as dust storm due to its observational frequency and range.

With the rapid development of the electric power projects and electrization of industrial corporations, more and more transformers have been used. When in operation, the real time supervision of Transformer Fault is very important to the secure operation of transformer. The Infrared imaging techniques played an important role in Fault diagnosing for transformer. The infrared imaging technique based on infrared radiation knowledge, by using this technique, the Fault modes of Power transform as well as the application of infrared imaging on Power transformer were studied. Then a series of practical engineering problems, such as the image shaping principle of infrared laser device, the utilizing of infrared laser device in power transformer fault diagnosis, the working procedure in real field operation, the acquiring of heat spectrum from fault transformer in field test, the analyzing of heat image spectrum etc, were considered and overcame. Finally, an example was presented by using the studied infrared heat imaging technique to diagnose the primary transformer at Baitaling substation. The results are closely according with the real situation.

A complex sensor of synchronous measurement of temperature and displacement with optical fiber is proposed in this paper. It can be used in the real-time measurement of temperature of turbine and longitudinal displacement of the leaf. The Measured temperature range is 300~800°C and the resolution is 1°C. The measured displacement range is 0~5rnm and the resolution is 0.01mm. The two signals can be discriminated by using four channels of quartz optical fiber and narrow-band filtering. By operation of the ratio between measurement signal and reference signal, the accuracy can be assured. The experiment results show that the sensor presented has properties such as fast response, good repetition stable work and good reliability.

We develop a 3D thermography imaging standardization technique to allow quantitative data analysis. Medical Digital Infrared Thermal Imaging is very sensitive and reliable mean of graphically mapping and display skin surface temperature. It allows doctors to visualise in colour and quantify temperature changes in skin surface. The spectrum of colours indicates both hot and cold responses which may co-exist if the pain associate with an inflammatory focus excites an increase in sympathetic activity. However, due to thermograph provides only qualitative diagnosis information, it has not gained acceptance in the medical and veterinary communities as a necessary or effective tool in inflammation and tumor detection. Here, our technique is based on the combination of visual 3D imaging technique and thermal imaging technique, which maps the 2D thermography images on to 3D anatomical model. Then we rectify the 3D thermogram into a view independent thermogram and conform it a standard shape template. The combination of these imaging facilities allows the generation of combined 3D and thermal data from which thermal signatures can be quantified.

Thales Anenieux has been manufacturing for two decades flexible light intensifier goggles that have been popular over numerous countries: thanks to the advent of uncooled microbolometer arrays, further outlooks are settled. Army Forces can have now at their command a multi-purpose and cost effective set of devices that answer most of the battlefield mission profiles. Thales Angenieux move from light intensifier goggles to low cost infared imagers and this smooth change is sketched out: our erlier experience on compact and user-friendly L.I equipment, especially in the field of the opto-mechanical design, has helped us to push forward the best compromises. Our product line policy is displayed: really, we have made a point of addressing many potential customers demands by singling out a modular approach. Further developments are now going on.

Radiation thermometry is just but one of many applications, both potential and realized, of infrared technology. During the SARS (Severe Acute Respiratory Syndromes) global crisis in 2003, the technology was utilized as a preliminary screening method for infected persons as a defense against a major outbreak, as the primary symptom of this disease is elevated body temperature. ATC timely developed a product designed specifically for mass volume crowd screening of febrile individuals. For this application, the machine must register temperature of subjects rapidly and efficiently, with a certain degree of accuracy, and function for extended periods of time. The equipment must be safe to use, easily deployed, and function with minimum maintenance needed. The ATIR-303 model satisfies all of the above and other pre-requisite conditions amicably. Studies on the correlation between the maximum temperature registered among individual's facial features, as measured under the conditions of usage, and the core temperature of individuals were performed. The results demonstrated that ATIR-303 is very suitable for this application. Other applications of the infrared technology in various areas, like medical diagnosis, non-destructive testing, security, search and rescue, and others, are also interest areas of ATC. The progress ATC has achieved in these areas is presented also.

In this paper, the application of wavelet transform for infrared image noise reduction is studied. Via threshold operation in wavelet domain of infrared image, it can reduce noise effectively without considerable loss of edge details. The discuss of this wavelet threshold segmentation algorithms is presented in this paper, and the methods of wavelet and threshold selection are also given. It has been proven that the wavelet threshold technology is an effective method for infrared image noise reduction.

A method for high time resolution thermal imaging is proposed. Under pulse heating condition, high time resolution snap-shot thermal image sequence from low frame rate is obtained by opto-mechanical scanning IR camera image sequence through the transfer theory of thermal wave and pixel correlative calculation.

The system is aimed at assisting inspection and monitoring of the degradation of tunnels in order to minimize maintenance and repair time. ATLAS 70 is a complete sensors/software package which enables thorough diagnosis of tunnel wall conditions. The data collected locally are stored on a computer hard disk for subsequent analysis in a remote location via elaborate dedicated software. The sensors and local computer are loaded onto a rail and/or road vehicle of specific design, i.e. with even travelling speed of 2 to 5 km/h. Originally, the system has been developed for the Paris Underground Company and has since been applied to rail and road tunnels, large town sewage systems, clean water underground aqueducts and electric cable tunnels.

It is difficult to detect the flue or the oil pipelines that had been buried underground on line. The oil in the pipelines must be heated to a certain temperature in some oil fields. Otherwise, the oil will freeze because of the paraffin mixed in it. The water in the flue pipelines must maintain a certain temperature in order to keep the house warm in winter. The temperature of the pipelines can conduct to the surface of the soil, so an uncooled focal plane arrays (UFPA) detector to measure the infrared energy of the soil surface can be used. The output of the thermal infrared detector can be expressed as the gray thermal pictures. According to the different degree of gray in the thermal pictures, we can process the pictures in terms of mathematics algorithm and obtain the temperature distribution of the soil surface, through which we can judge the direction of the pipelines underground. The advantage of the method is simple operation, direct display and harmless to human and the environment.

Wide film detect system, studied in the paper, is one kind of industry vision system. Wide film is useful recording medium, such as photograph, press and medicine. In the course of production, one main problem is the film is scathed by these transmit rolls. It will affect later imaging effect directly. How to assure its quality is an important task. Now, the film detection is a manual work and only some selected samples could be detected. The detection will be done after all production courses are finished. So, it is a difficult task to assure the film quality. In the paper, a wide film detect system was studies. The film detection task could be real-time operated when the wide film detect system is assembled with production line. The film detect system, like other industry vision system, is composed of optical system, CCD sensor, image frame grabber, light source and computer. The detection principle is based on image processing method. One point need to be shown, that is a suit light source is very important to the whole detection system. The light source shouldn't damage the film and it must have enough power to assure the CCD sensor could detect. Infrared LED, which main wavelength is 940nm, was selected as source light. The detection speed is up to 90 m/min, detection width is 1300mm and detection resolution could up to 0.5mm at the operation direction and 0.05mm at the film width direction.

Principal Component Regression (PCR), Partial Least Square (PLS) and Artificial Neural Networks (ANN) methods are used in the analysis for the near infrared (NIR) spectra of glucose in the whole blood. The calibration model is built up in the spectrum band where there are the glucose has much more spectral absorption than the water, fat, and protein with these methods and the correlation coefficients of the model are showed in this paper. Comparing these results, a suitable method to analyze the glucose NIR spectrum in the whole blood is found.

Terahertz (THz) radiation, generated by ultra short laser pulses, occupies a broad band on electromagnetic spectrum chart. This radiation band belongs to far-infrared. It is a new research field of studying THz radiation interacting with materials especially with biomaterials. The paper shows experimental results of five plant oil samples from different kind of plants and two kinds of animal fat samples by using THz-TDS (THz time-domain spectroscopy) technology. The refraction indices and the absorption coefficients of these samples are measured in the range from 0.2 to 2.0 THz. The results show that different oils have different refraction indices. For oil samples, refraction indices decrease slowly while their coefficients of absorption increase with the increases of THz frequency. For the animal fat samples, the refraction indices show almost no change while the absorption coefficients increase with the increasing THz frequency. The absorption coefficients increase with the increasing temperature.

According to the imaging mechanism of the IR image, the histogram of the IR image, whose background is composed of the sea area and the sky area, usually has two apices and one vale. Based on this character of the histogram, the paper proposes a background suppression method, which combines the sea-sky area segmentation with the median filtering. Then, in order to reduce random noises in the image whose background has been suppressed, the local threshold-a digitizing method-has been showed in the paper. In this method, the image whose background has been suppressed is divided into some blocks, and the different block has the different threshold. The target motion is continuous and the noise motion is random, so the paper presents a sequential target detection method on the centroid track accumulation. A large number of experiments show that the methods presented in the paper can exactly detect the moving small target in the IR clutter background containing sea and sky areas.

The main Infrared Search and Track systems (IRST) purpose is to realize optimal discrimination between true targets and background clutter (false alarm). In such single band systems, background prediction is frequently used for detecting small targets. However, detection performances are strongly influenced by background gurgitation. The method based on maximum background model can reduce this kind of influence. But present background prediction methods choose background pixels around the prediction pixel from every direction, as a result, background pixels around the target will be 'poisoned' by target, and contrast will be greatly reduced accordingly. Threshold chosen to detect the target in the predicted residual image will decrease, and this will result in too many false targets and increase false alarms. For the small targets detection in IR images, a method of background prediction based on multi-band background model is proposed. For the purpose of removing the target poison, an improved rule of selecting background pixels according to the certain spectral difference between the expected target and background has been developed in this method. The use of this information is based on theoretical spectral radiance discrimination in LWIR and MWIR bands, between targets and backgrounds. When the current spectral parameter matches spectral background response, the current pixel is judged as a background pixel, and involve in background prediction operation, otherwise, it is judged as a target pixel, and will not involve in this operation. The multi-band background model, which improves the performance of small targets detection, eliminates the effect of target on the background prediction, achieves more accurate prediction of background, and increases the contrast of target and background. This is a significant development to the background prediction algorithm by extending to multi-band domain. Simulation results validate the effectiveness of the algorithm in this paper.

Detecting a target out of its surrounding background is a major problem in various infrared seekers. The cluttered scenarios present extreme challenges for the modern IR seekers and are the focus of technology efforts. So, a complete performance evaluation model should include all of the following elements: i) the background ii) the target, iii) the atmosphere, iv) the sensor, and v) the image processing algorithms. Since the staring IR seeker systems are emerging as the latest application of the thermal infrared technology, it suffers the most from the lack of complete performance evaluation models. We present a robust performance evaluation technique for staring IR seekers based on signal-to-interference ratio (SIR), with the quantitative description of the background clutter and detection algorithms emphasized. The power transfer functions of the optical system, detector and electronic are established to describe energy transmission of the signal and interference (noise and clutter) through the IR seeker, and the targets' radiant intensity statistics as well as the noise's statistical characteristics are also taken into account. In order to quantify the background clutter, we use a clutter measure based on its energy content - power spectral density (PSD). Based on this measure, a SIR is developed to analyze detection performance. Furthermore, the influence of several classical detection algorithms on the SIR is analyzed.

Imaging spectrometer is characteristic of high spectral resolution, high spatial resolution, multitudinous bands and mass data. The ground object information of hyperspectral image can be used on target identification. On the base of theory on hyperspectral remote sensing imaging technology, the paper mainly introduces three spectrometers designed by Shanghai Institute of Technical Physics, CAS. There are CMODIS, which is the main payload of SZ-3 spaceship, OMIS and PHI, which are airborne sensors. Some applications about those sensors are discussed in the end.

The geometric distortion of infrared image, which was created by the large-sized relative aperture optical system. It could be corrected by the digital image processing technology. The magnitude of distortion would be enlarged quickly with the enlargement of relative aperture. Though the distortion could not impact on the articulation of the image, it would affect geometric location precision of the image directly. In this paper, the distortion correction of uncooled large-sized relative aperture infrared imaging system was discussed and the mathematical model of distortion correction was established. A algorithm of digital image processing was presented and applied based on control points by combining polynomial warping and space variant linear image interpolation. The method of polynomial warping was used to establish the locality relationship between the original image and the distortion ones. The space-variant linear image interpolation provided an efficient way to rebuild the frame of images. The computational costs of the proposed approach are very little and the precision is almost as high as the method of bicubic interpolation when compared to those of state-of-the-art nonlinear interpolation operators

In this NIR Spectrometer the capability of sending light optical fiber is limited. The intensity of light from the sending light through optical fiber is very weak. Some good methods to solve this problem are introduced, which makes the signal stronger and easier to process. The important method is Lock-in Amplifier(LIA)bases on Correlation Detection.The ratio of signal to noise (S/N) is greatly improved through the phase sensitivity detection. The method of acquiring the weak signal, which can solve the problem of getting signal in NIR spectrometer, are introduced.

While using long wave FPA infrared detector to detect target, there are some faults in the infrared detector such as speckles add to infrared image we shot. The inherent faults of the infrared detector are solved by means based on difference between the two continuous frames. By setting different grades of gray value, the noise such as all speckles and mostly background in the two continuous frames is eliminated. Consequently, The area where the target moved is picked up.

This paper introduces a new type of infrared light source constructed by silicon micro-bridge manufactured on silicon substrate using MEMS technique. Electric current flowing through the micro-bridge makes its temperature goes up and radiates infrared light as traditional lamp. A simulation of characteristics of the infrared standard source calculated by finite element method is consistent with the test value. The radiation power, depending on micro-bridge size, is obtained from 1mW to 500 mW. The infrared light source can use electric chopping instead of mechanical chopping as traditional lamp for it's fast response time with typical 4 ms.

Micro-scanning is an important technique in high-resolution IR imaging field. It can increase the system resolution and improve the performance of imaging systems. For the design of super-resolution IR imaging system, it is necessary to choose the optimum micros-canning mode according to the particular fill factor of sensor. Hence, it is very important to study the effect of fill factor on the micro-scanning image quality. Under some assumptions, this paper introduces the sampling-averaging MTF of detector array at spatial Nyquist frequency as a figure of merit to quantitatively evaluate the improvement of different micro-scanning modes to image quality for different fill factors (1, 2/3, 1/2, 1/3) of infrared sensor. Finally, typical sampling imaging processes of focal plane array with the above fill factors are simulated. Experimental results qualitatively descript the effect of fill factor on the micro-scanning image, and show a good agreement with theoretical analysis.

Nonuniformity is a pressing problem particularly for uncooled focal-plane arrays imaging systems. Based on the theory of Least Mean Square (LMS), an algorithm is developed to compensate for the nonuniformity response in focal-plane arrays (FPA). The proposed algorithm is able to reduce various errors caused by noises, sampling, etc. A correction model of multi-order function is presented which has least-mean square error, and then by utilizing response values at several known temperature points the coefficients of this function are obtained via the theory of LMS fitting. Taking one pixel as example, the graph of the correction error is drawn. The ability of the algorithm is demonstrated by using simulated and real data. What’s more, the effects of this algorithm in nonuniformity correction are revealed as opposed to those of some traditional algorithm. To compensate response drift along time, a method based on estimating motion in continuous frames is presented.

Intensity, range and Doppler images can be obtained by using laser radar. Laser radar can detect much more object information than other detecting sensor, such as passive infrared imaging and synthetic aperture radar (SAR), so it is well suited as the sensor of object recognition. Traditional method of laser radar object recognition is extracting target features, which can be influenced by noise. In this paper, a laser radar recognition method-Support Vector Machine is introduced. Support Vector Machine (SVM) is a new hotspot of recognition research after neural network. It has well performance on digital written and face recognition. Two series experiments about SVM designed for preprocessing and non-preprocessing samples are performed by real laser radar images, and the experiments results are compared.

Since the conventional denoising algorithms have not considered the influence of certain concrete detector, they are not very effective to remove various noises contained in the low signal-to-noise ration infrared image. In this paper, a new thinking for infrared image denoising is proposed, which is based on the noise analyses of detector with an example of L model infrared multi-element detector. According to the noise analyses of this detector, the emphasis is placed on how to filter white noise and fractal noise in the preprocessing phase. Wavelet analysis is a good tool for analyzing 1/f process. 1/f process can be viewed as white noise approximately since its wavelet coefficients are stationary and uncorrelated. So if wavelet transform is adopted, the problem of removing white noise and fraction noise is simplified as the only one problem, i.e., removing white noise. To address this problem, a new wavelet domain adaptive wiener filtering algorithm is presented. From the viewpoint of quantitative and qualitative analyses, the filtering effect of our method is compared with those of traditional median filter, mean filter and wavelet thresholding algorithm in detail. The results show that our method can reduce various noises effectively and raise the ratio of signal-to-noise evidently.

Using high data optical transmitters for satellite communication channels has generated an interest in laser communication systems ground-to-satellite data links. The atmospheric turbulence causes laser intensity fluctuations that can seriously degrade the reliability and performance of such laser communication links. In the ground-to-satellite link, the atmospheric turbulent's thickness is much less than the path length. Taking into account the large size of the beam at a satellite in orbit, the spatial coherence radius at the satellite is many times larger than the probable receiving aperture of the satellite's optical antenna. Thus the aperture behave of uplink essentially like a point detector without aperture averaging. An analysis of multiple beams compensation for atmospheric turbulence induced scintillation is carried out in this paper. Using multiple incoherent beams transmit synchronically optical signal from dividable apertures, separated by a distance larger than the atmospheric coherence diameter. The convolution integration to determine what happens for two independent random variable, we generalized this method to multiple independent random variables. According to probability theorem, the multiple beams distribution of the irradiance is given with different scintillation index. For this analysis we assume that the single-beam probability distribution function model of the irradiance is the gamma-gamma distribution. In our analysis of this simulation model, it shows that the adverse effect of scintillation on the communication lasers can be minimized with multiple transmitters under weak, moderate, and strong turbulence conditions. The scintillation index was reduced as the number of laser transmitters was increased. So, fluctuation on the uplink/downlink communication beams can effective reduced by multiple transmitters.

A new glass of Lu₂O₃-B₂O₃-SiO₂-Na₂O-Er₂O₃ system is prepared by the technique of high-temperature melting at different temperatures and the formation range of the glass is experimentally obtained. Effects of the B₂O₃ content on the infrared spectral properties such as the 1.5 μm emission bandwidth corresponding to ⁴I_13/2→⁴I_15/2 transition and the Judd-Ofelt parameter Ωt (t = 2, 4, 6) of Er³⁺ ions in the glass has been observed. The glass exhibits big integrated emission cross sections for the 1.5 μm emission band. Excellent thermal stability of the glass has been demonstrated using differential thermal analysis. The Er³⁺-doped lutetium borosilicate glass is a great candidate for broadband erbium doped fiber amplifiers.

Laser radar has been widely used these years and the hardware-in-the-loop (HWIL) testing of laser radar become important because of its low cost and high fidelity compare with On-the-Fly testing and whole digital simulation separately. Scene generation and projection two key technologies of hardware-in-the-loop testing of laser radar and is a complicated problem because the 3D images result from time delay. The scene generation process begins with the definition of the target geometry and reflectivity and range. The real-time 3D scene generation computer is a PC based hardware and the 3D target models were modeled using 3dsMAX. The scene generation software was written in C and OpenGL and is executed to extract the Z-buffer from the bit planes to main memory as range image. These pixels contain each target position x, y, z and its respective intensity and range value. Expensive optical injection technologies of scene projection such as LDP array, VCSEL array, DMD and associated scene generation is ongoing. But the optical scene projection is complicated and always unaffordable. In this paper a cheaper test facility was described that uses direct electronic injection to provide rang images for laser radar testing. The electronic delay and pulse shaping circuits inject the scenes directly into the seeker's signal processing unit.

Basic on the discussing of the techniques for enhancing the space resolution of the IR FPA system, the adaptive dummy electric micro-scanning technique is given. By the technique, IR FPA image pixels can be enhanced, and at the same time, the edge of image is enhanced effectively, the detail of the image is remained. The experiment result shows that the technique is effective.

In this paper, methods of adopting NIR spectra to measure milk constituents and Direct Orthogonalization (DO) pre-processing are studied. Based on the spectra of representative solutions, the DO method was employed to filter the signal noise that is irrelevant to the concentration being measured. The predictions of the Partial Least Squares (PLS) Regression models with and without the DO pre-processing are evaluated. During the experiments, the transmitted spectra of a water solution with glucose and NaCl mixture and the scattered reflection spectra of milk are acquired respectively in the near infrared region of 1000~1700nm using a homemade NIR Spectral System for measuring milk constituents. With the DO pre-processing of the spectroscopic data, the number of the optimal Principal Component (PC) of the PLS model is reduced. It should be noted that the sum of this PC number and the PC number corresponding to the DO preprocessing is equal to the optimal PC number of the PLS model without DO pre-processing. After the DO pre-processing, the Root Mean Square Error of Cross Validation (RMSECV) of PLS model is slightly reduced whereas the Root Mean Square Error of Prediction (RMSEP) is reduced significantly.

The solving question of image compressing is how to reduce the image data to a minimum. The rebuilt image using the data is satisfying. The characteristics of the infrared image are analyzed. After the analysis of infrared image wavelet coefficients, a vector quantization algorithm based on wavelet transform and the advanced one are proposed. The two algorithms are both realized by programming, and the results of the experiments are analyzed and compared, which shows that the proposed algorithms for infrared image compression can be feasible.

In this paper, we present a novel M-ary modulation scheme enhanced by zero correlation zone(ZCZ) sequences to attenuate the multipath dispersion in the indoor infrared communication systems. It is proved to offer a high speed infrared communication with good bit-error-rate(BER) performance and bandwidth efficiency.

Dual Head Pulse Interval Modulation (DH-PIM) is a modulation technique using in optical wireless communications. In this paper, the performance of DH-PIM is analyzed in the presence of intersymbol interference. The channel impulse response and symbol error rate versus normalized delay spread are discussed. A soft-decision decoding technology is presented, which can improve the performance of DH-PIM.

According to heat conduction equations and especial boundary conditions, the photothermal emission distribution of two-layer thermally uniaxial thin films has been acquired in the cylindrical coordinate system by Hankel transformation and retransformation. Applying specific parameters to two-layer thermally uniaxial thin films, the ones are discussed. The larger are the ratios of longitudinal heat conductions and transverse ones of the thin films with high thermal diffusivity, the larger are the phase changes of the photothermal signals in the thin films. Neverthless, for the thin film with low thermal diffusion, the different ratios of longitudinal heat conductions and transverse ones are potty influences on photothermal signals. And, the smaller are optical absorption coefficients, the more evident are the influences on phases because of frequency changes.

A method has been put forward for design small-angle scanning mirrors to increase the scanning frequency of broad beam scanner, and experiment with this designed scanning mirror has been carried out. The size of the elliptical spot irradiated by the scanning beam is worked out according to the size of the beam and the scanning angle. Based on the ellipse inscribed, a suitable octagonal mirror is produced as the scanning mirror. We experimented with the reflection mirror designed ourselves loaded on M-6870 scanner produced by the Cambridge Technology Inc. The result indicates a small-angle mirror could increase the scanning frequency to a great degree.

In this paper, we propose a DSSS transmission scheme called T-ZCZ (Three Zero Correlation Zone) Keying for indoor infrared communications. This scheme can successfully remove inter-symbol interference (ISI) incurred by multipath dispersion and improve the system throughput drastically. We present the system modelling and show that it can offer a better Bit-Error-Ratio(BER) performance and higher data transmission rate, especially in multipath infrared channels for multiple users.

The watershed algorithm from mathematical morphology is powerful for segmentation and often produces more stable segmentation results, including continuous segmentation boundaries. However, direct application of the watershed segmentation algorithm generally leads to oversegmentation due to noise and other local irregularities of the gradient. Oversegmentation can be serious enough to render the result of the alorithm virtually useless. An approach used to control oversegmentation is based on the concept of markers. A marker is a connected component belonging to an image. In this paper, considering that there are two small but very brighter regions associated with the chimneys of ship, the topological properties of IR ship target can be used to restrict the algorithm. So, we have internal markers, associated with IR ship target, and external markers, associated with the background. Experimental results show that, when the original watershed segmentation has noisy boundaries or wrong limbs attached to the object of interest, the proposed method overcomes those drawbacks and yields a better segmentation.

In recent years, with the rapid development of laser radar technology both in military and civil fields, the research on laser radar has come to the stage of application throughout the world. This paper studies the offset frequency locking system used for a short-pulsed laser outdoors. It is often the case that if the received IF signal bandwidth of coherent laser radar becomes more narrow in coherent detection, the signal noise ratio will be improved greatly. Therefore the technique is needed for offset locking the heterodyne frequency between two lasers. However the unstable ambient temperature will produce an effect on the behavior of a gas laser, and the offset locking technique should have such characterized features as in a frequency offset locking loop used for pulsed lasers. The heterodyne frequency between two lasers is necessitated to have a wide enough bandwidth so as to prevent itself from a loss of locking and to have a high enough discriminating frequency accuracy so as to make the radar possess a high accuracy of measuring the target speed. In order to attack the problems mentioned above, this paper designs an offset frequency locking system with two frequency discrimination loops. One has an all-digital frequency discriminator with a bandwidth of 600MHz and accuracy of 5MHz in discriminating frequency to an optical pulse width 30 ; the other has a coincidence gate circuit discriminator with a bandwidth of 20MHz and an accuracy of less then 500kHz in discriminating frequency to an optical pulse width 30 ns.

This paper describes a display platform of imaging laser radar system. A display platform is developed for imaging laser radar system, as well as the design, compose and software flow of display platform is introduced. We use Visual C++ 6.0 to build it in Windows system, and display the intensity and distance image of the target. Farther, display platform realizes the grayscale transformation of the image, and gets the different pictures with the different grayscale transformation of the same image. Display platform also can select the specific distance value of the target before detecting and save the image data. The soft met the need of laser radar imaging through experiment.

Forward Looking Infra-Red (FLIR) image segmentation is crucial for Automatic Target Recognition (ATR). This paper presents a thresholding method for image segmentation by performing fuzzy partition on a two-dimensional (2-D) histogram based on maximum entropy principle. We combine the original image with its smooth image to form a binary set, called a "generalized image", and the histogram of the generalized image is a 2-D histogram. In order to adequately utilize the intrinsic information of the FLIR image, we adopt a newly defined fuzzy partition of two fuzzy sets, dark and bright, basing on 2-D histogram. Also we define the corresponding 2-D membership function, which represents the membership of darkness and brightness for each element in the binary set, respectively. The entropy is used as a measure of fuzziness. Based on the Shannon function, we define a 2-D fuzzy entropy. The total fuzzy entropy is the sum of the entropy of each block. Therefore, the fuzzy region can be determined by maximizing the total fuzzy entropy. A genetic algorithm is employed to find the optimal combination of all the fuzzy parameters. Experiment results show that the proposed method gives good performance.

According to the imaging procedure an infrared picture include an object image, a background image and a noise image. The object image and the background image are main body of an infrared image; noise image is the disturbance on the main body. This paper discusses the infrared image quality from three aspects: information capacity, image detail and pseudo-s/n ratio, it has fine image quality in comparison.

Due to their interesting physical and chemical parameters, tunable transversely excited atmospheric-pressure(TEA) CO₂ lasers are widely utilized in scientific and industrial applications. The CO₂ differential absorption lidar (DIAL) is an effective tool for remote measurement of pollutant gaseous concentration of the atmosphere over large areas. Many pollutant gases have strong absorption lines within the spectral range of CO₂ laser wavelength tuning. In addition, the radiation of CO₂ laser is well distributed in the atmosphere, coinciding with the "transparency window" of the atmosphere. Therefore the wavelength tunable TEA CO2 laser is an ideal optical source for DIAL. Most existing instruments for measuring the laser wavelength are only suitable for the measurement of continuous wave and stable frequency output. With the attempt of measuring the wavelength of pulsed TEA CO₂ laser, an experimental setup is established which consists of two main portions, namely auto-scanning grating monochromator as the color dispersion system and Boxcar integrator. In the experiment of tuning TEA CO₂ laser, the wavelength of CO₂ laser is observed and measured by means of integrating method. The accuracy of measurement in the mid-infrared region attains 1nm.

Terahertz (THz) region occupies the portion of the electromagnetic spectrum between the infrared and microwave bands, with the frequency range from 0.1THz to 10THz (10×1012Hz). Because THz radiation was difficult to generate and detect, the characters of THz had been unknown for a long time. Now, there are two primarily classes method to generate and detect THz wave, including continues THz wave system and pulsed THz system. Among them, pulsed THz system is based on ultra-fast pulsed generation and detection using mode-locked lasers which only became commonly available in the late 1980s. Relying on pulsed THz system, THz pulse spectroscopy, also called THz time-domain spectroscopy (THz-TDS) has been applied in study of the characters of materials over the last decade. In such a short period, because of the large variety and complicacy of big bio-molecules, many different THz pulse spectroscopy methods have been developed to study their collective vibration modes, but not been systematically summarized yet. In order to promote the THz pulse spectroscopy, this paper provides a general review of the achievements using the technology in study of biological molecules, particularly focusing on the technology and the advancement in sample preparation, optical path design, data processing and spectrum analysis.

How to turning down the heat of aircraft infrared picture, how to get stealthy. To make a stealthy aircraft, designers had to consider a lot of key ingredients. This paper mainly introduces aircraft stealthy and discussed the efficiency of aircraft signature suppression. We describe testing process, measure and analyze the characteristics of aerosol scattering and absorption and present testing data of aircraft plume signature suppression. It covers the waveband from 2μm to 14μm. Another, infrared radiation temperature be minimized by a combination of temperature reduction and masking radiation temperature.

Pb_1-xGe_xTe is a pseudobinary alloy of IV-VI narrow-gap semiconductor PbTe and GeTe, of which maximum refractive index corresponds to the ferroelectric phase transition. Since the temperature coefficient of refractive index can be tunable from negative to positive by changing the Ge composition, it is possible to utilize the intrinsic property in the fabrication of infrared thin-film interference filters. A simple Fabry-Perot type narrow-bandpass filter was fabricated, in which Pb_0.94Ge_0.06Te was substituted for PbTe. It was found that the low-temperature stability of the filter is obviously improved: in the temperature range of 80-300 K, the shift of center wavelength with temperature is reduced from 0.48 nm.K^-1 to 0.23 nm.K^-1; furthermore, the peak transmittance of filter fabricated with Pb_0.94Ge_0.06Te is ~3% over that fabricated with PbTe.

Color night vision through fusion of images derived from visible and thermal infrared sensors has come into application. A lot of research of perceptual or subjective evaluation of color fusion algorithms is conducted by the TNO, MIT and NRL[1-5]. Objective evaluation is becoming an increasing issue. A good fusion algorithm should preserve or enhance all of the useful features, i.e., targets pop out and content or details from the source images. Objective: The goal of our research is to predict details and target detectability of color fusion images by measuring image contrast. Methods: A color image contrast metric[11], which was designed to compute how much details for natural images, is employed to measure details and target detectability of color fusion images in this paper. A sub-band contrast index is defined, the first band contrast index indicates the level of details, and higher band contrast indexes indicate the level of target detectability. Results: The perceptual details have high correlation with the first sub-band contrast indexes, and the perceptual target detectability has correlation with higher sub-band contrast indexes. This means the sub-band contrast indexes may predict details and target detectability, however, noise effect on details need to be considered and prediction of target detectability need to be improved.

Two developed color image fusion techniques, the MIT scheme and the TNO scheme, are applied to visible and infrared images. They are enhancement and nonlinear methods. This paper provides a discussion of the linear fusion scheme once again. At least two conclusions can be testified by the fusion experiment on two sensor images in this paper: one is the linear fusion scheme has good performance in some images modalities; the other is the linear fusion has better performance in the fused color space YUV than in the RGB. A key problem of the linear fusion, how to assign or weight sensor images to three channels of a color space, was studied with the correlation between dual-sensor images, and experimental results show that the assignment or weight is related with the correlation between sensor images. But this study is mainly for the Y channel in the interest of preserving the details from both of two sensor images, and the relationship between the assignment or weight of a linear fusion and the correlation between sensor images need to be studies further in future.

This paper is centered on the development of reagent-free method based on Fourier transform mid infrared (FT-MIR), near infrared red (NIR) and Fourier transform (FT)-Raman spectroscopy. Suitable spectral wavenumber regions were selected for principal least square (PLS) regression and calibration models developed. In MIR, urine sample measured with Horizontal ATR, which is the accessory of Perkin-Elmer Spectrum GX Spectrometer, and the important range is 900-1800 cm^-1. NIR spectra are obtained for each sample with 1mm pathlength. Absorption spectra of urine samples in 5000~4200cm^-1 is used for PLS regression. The Raman spectra were recorded with a Bruker IFS 66 spectrometer with an FRA 106 FT-Raman accessory unit. The FT-Raman spectra of albumin power and albumin solution is recorded. The main noise is form water. The root mean square error of prediction (RMSEP) of glucose is 34.9 mg/dL(MIR), 31.56mg/dL(NIR) , and the RMSEP of albumin is 23.2mg/dL (MIR), 17.9mg/dL(NIR). Result indicated that FT-MIR and NIR spectroscopy could be used for rapid analysis of urine. FT-Raman spectroscopy could applied for compositional identification.

We will use InGaAs and Ge based reflection type trap detectors as a detecting element and lasers as light sources to realize the absolute power and responsivity scales in the near infrared region. The output of lasers should be stabilized in order to make measurements on the metrological level. Therefore, we have established a home made laser intensity stabilization optics in the laboratory. The intensity stability of infrared lasers was reached to a level of 5x10^-5 with this system. We have employed a spatial filter, which consists of a 10X objective, a 25 μm pinhole and a Plano convex lens in order to generate a clean beam with the desired dimension Circular power distributions and Gaussian properties of the beams were analysed by using a CCD beam profiler.

We study the 1/f noise currents and dark currents in LWIR HgCdTe photodiodes with different passivation. The diodes are fabricated by ion implanting boron on MBE HgCdTe with x=0.2173. One kind of photodiodes was passivated by ZnS and the other kind was passivated by CdTe/ZnS. Both dark currents and 1/f noise currents were measured at several reverse bias voltages. The measured dark currents of the photodiodes are analyzed using current model fitting methods. The different dark current components, such as diffusion current, generation-recombination current, trap assisted tunneling current and band-to-band tunneling current, at various biases voltages can be separated from the measured dark currents. The measurement results demonstrate that the dominant mechanism that produces 1/f noise in HgCdTe photodiodes with either passivation is tunneling. When the reverse bias voltages are less than 200mv, the main mechanism that produces 1/f noise is trap assisted tunneling. In this case, the 1/f noise currents of the photodiodes passivated by ZnS are smaller than those passivated by CdTe/ZnS. When the reverse biases are larger than 200mv, the band-to-band tunneling currents of the photodiodes passivated by ZnS are much larger than the photodiodes passivated by CdTe/ZnS. And the 1/f noise currents of the ZnS passivated photodiodes are larger than the different passivated one. In order to investigate the effect of surface passivation on the stability of two kinds of diodes, R-V characteristics and 1/f noise of the diodes were measured after vacuum baking for 10 hour at 80°C, the photodiodes passivated by CdTe/ZnS show higher performance compared with the diodes passivated by ZnS after baking.

The dislocation densities in HgCdTe films grown on CdZnTe by Liquid Phase Epitaxy (LPE) are calculated based on their effects on the x-ray rocking curves. The dislocation densities derived from three kinds of methods, i.e. FWHM of X-ray double axis diffraction, Williamson-Hall plot and Pseudo-Voigt function, are approximately the same. It is found that the thickness of HgCdTe epilayers about 10 um is large enough so that effect of crystallize size on the rocking curves width can be ignored. Because the intrinsic FWHM of HgCdTe and the instrumental function of high resolution X-ray diffraction are neglected in Williamson-Hall plot and Pseudo-Voigt function, the dislocation densities obtained by these methods are a little larger than those derived from the first kind of method. Among three kinds of methods, Pseudo-Voigt function method is the easiest one to fit the rocking curves and calculate the dislocation densities.

Some results on the arsenic incorporation in MBE-grown HgCdTe are described. It was found that arsenic surface sticking coefficient during HgCdTe growth was very low, ~1x10^-4 at 170°C being very sensitive to the growth temperature. The annealing experiments for activation of arsenic were performed, and the importance of the ambient mercury for the arsenic site transfer was confirmed. It was found that the arsenic dopants could be fully activated as acceptors by anneals at 285°C under the mercury-saturated pressure. The activation energy for the isolated arsenic acceptors in HgCdTe (x=0.27~0.33) was determined as to be 19.5 meV, which decreases with (Na-Nd)^1/3 at a slop of 3.1x10^-5 meV cm . The diffusion coefficient of arsenic in HgCdTe of 1.0±0.9x10^-16 cm²/sec, 8±3x10^-15 cm²/sec and 1.5±0.9x10^-13 cm²/sec were obtained at annealing temperatures of 240°C, 380°C and 440°C under mercury saturated pressure, respectively.

Variable temperature standard blackbody (VTSBB) is used as the standard radiation source in laboratory to calibrate working blackbodies. Calibration of VTSBB is difficult for higher requirement in emissivity and temperature. Null Balance Radiation Comparator for comparison of two IR-sources is a sensitive system, but the temperature of the source under test must be got first by other methods for emissivity calculation. The extra procedure of temperature test does not satisfy the requirement of calibration accuracy of VTSBB. By using spectral method, the emissivity and the temperature of a VTSBB will be deduced simultaneously from a series of ratios of radiance measurement. Experiment apparatus consists of five parts: IR-spectroradiometer, IR-collimator, slide stage, freezing point blackbodies (FPBB), and VTSBB. FPBB and VTSBB are laid parallel on slide stage to insure the same distances between their apertures to the IR-spectroradiometer. Radiance of two blackbodies is obtained respectively at points of selected wavelength. According to the principle of least square, emissivity and temperature of VTSBB are solutions of two radiation equations. Wavelength ranges of test are 3μm to 5μm and 8μm to 14μm. The experiment standard deviations are 0.0013 for emissivity and 0.3K for temperature.

In this paper, a NIR Spectral System based on Acoustic Optical Tunable Filter (AOTF) was developed for measuring milk constituents. Factors affecting the repeatability of measuring spectra of the system were analyzed by using the transmitted spectra of Ultra-High Temperature (UHT) sterilized milk. Orthogonal experimental design method was employed to determine the significance level of these factors and the optimal condition for measuring spectra of the system. It is concluded that the crucial factor affecting the spectra repeatability is the ambient temperature. Further temperature testing results show that, when the environmental condition is basically invariant, the temperature of the AOTF crystal is basically constant and the drifting amplitude of wave number is within 0.5cm^-1, when the ambient temperature varies, the temperature of AOTF crystal changes correspondingly. The drifting of wave number is about 1cm^-1 when the temperature of AOTF crystal changes 1°C. It is found that the wave number drifting increases with decreasing temperature of AOTF crystal. These testing results are of important significance to further improve the measuring accuracy of the system.

IR imaging simulation is an important way to design and assess the IR missile, and the key of simulation is the generation of IR image. The generation of IR image is worthful in military and economy. This Paper simulates the IR image of warship with the computer technology and theoretical analysis. Being constructed with 3DS software, the geometric model of warship is divided into facets in according to the infrared characteristic which is analyzed in various environments and moving states. Based on infrared physics and heat transfer, radiation and convection and conduction are computed respectively for each facet, and the equation in steady state is obtained. The full infrared model of warship is built, which includes the radiation, convection and conduction between different parts of the warship, and which also includes the radiation, convection of environment. To calculate the radiation exchange, the formula based on view factor is deduced, and the temperature distribution is computed with the formula. Based on the temperature field of the warship, the radiance can be obtained with the temperature in according to the Planck Distribution Law, and IR images of the warship can be generated.

The current-voltage (I-V) characteristics of HgCdTe photodiode under up to 33 dB of irradiance level have been investigated with a continuous-wave solid state laser. Short-circuit photocurrent and open-circuit photovoltage are observed to be saturated under high-level photon injection. It is found that the increasing of reverse bias can dramatically improve the response linearity of photodiode under high irradiance. The I-V characteristics and dynamic resistance versus bias relationship of photodiode under irradiance cannot be explained satisfactorily with present theory. Considering the effect of irradiance on photodiode series resistance and parallel resistance, an interpretation based abrupt junction model is presented to account for the effect of bias on I-V characteristics of HgCdTe photodiode.

This paper deals with the problem that a great number of rotary joints are suffering the conflict between high efficiency of signal dynamic coupling and low requirement of precision mechanism. As a solution, a specific design of the infrared spatial interconnection rotary joint is presented accompanying with the discussion of requirements for the mechanism and the circuit. Benefit from infrared data interconnection between the stator and the rotor, the security of data transfer is ensured and the off-axis angle can vary from 0º to 30º, which contribute to a simpler mechanism and a compact rotary joint. Relative experiment shows that with this rotary joint, signals can be transmit securely, and the efficient data transmission speed is up to 1.4Mbps under Windows 2000 circumstance.

CdTe growth on Si is the major challenge for HgCdTe. The recent results on MBE growth of 3-in CdTe(211)B/Si are reported. The Si substrates were (211) orientated, and a low temperature surface cleaning process was employed. To obtain twin-free CdTe(211)B, nucleation process of ZnTe on Si was studied at different conditions. Under the optimal growth condition, the average FWHM value less than 120 arc sec of twin-free CdTe(211)B films for 10-12μm was obtained. The lowest FWHM value of 100 arc sec was achieved.

Recently, Semiconductor sensor and thermal conductivity sensor are widely used for gas detection in transformer online monitors. Since the long-time stability or precision of these sensors is not satisfactory, the present researcher studied the application of FTIR in such monitors. In the wide measuring range of online monitoring, Absorbance Law is not always applicable, thus a non-linear calibration model was necessary. Experiments were done to set up the calibration model. A gas dilution system was designed. With the system, standard samples of fault gas including CH₄, C₂H₂, C₂H₄ and C₂H₆ were diluted to different concentration. BOMEM MB104 FTIR Spectrometer was used to collect spectra of gases. Curve fitting of the output of FTIR was done, and the effect of quantitative feature and concentration range on quantitative analysis was investigated. In addition, the lowest detection limit was tested. Experiment and calculation results show: accuracy can be improved by taking strong peak height at low concentration range, taking peak area or weak peak height at high concentration range as quantitative feature, and using third order polynomial to fit the output curve of FTIR. The lowest detecting limit of C₂H₂ with 2.4m gas cell is below 0.3ml/l and that of 10cm cell is below 3ml/l.

The B⁺ ion implantation technology has been utilized to fabricate the n⁺ on P HgCdTe photovoltaic arrays with the HgCdTe epitaxial materials grown by Liquid Phase Epitaxial method. The effects of the implanting energy and dose on doping profile and approximate junction depth were calculated in detail, the calculated results are well consistent with the measurement results by the Second Ion Mass Spectrum experimental technique (SIMS). The 10×10 photodiode arrays in which each pixel size is nominally 20×20 μm² and the pitch is 30 μm were made to investigate the electro-optic performance of devices. The device characterization such as array uniformity and optical crosstalk was non-destructively investigated by the technique of a scanning laser microscope. The two dimensional maps of Laser beam Induced Current (LBIC) signal have shown the good uniformity for the fabricated arrays, and there is no optical crosstalk between the arrays for the used B⁺ ion implantation conditions at the implanting energy of 130Kev and the dose of 2E14cm^-2. The primary performance of photodiodes the zero bias dynamic resistance junction area product R₀A, infrared response spectrum, and the detectivity D* have been measured, and the typical values for the test photodiodes with cutoff wavelength of 9.2 μm measured at 77K are: R₀A=13.5Ω·cm², average blackbody detectivity D* =7.18E10cm.Hz^1/2W^-1.