Abstract:Au-doped Hg1-xCdxTe epitaxial layer materials were grown by using a vapor phase epitaxial method. The layer materials were characterized by a Fourier spectrometer and a metallographic microscope. The longitudinal distribution trend of Au in the Hg1-xCdxTe epitaxial layer and CdZnTe substrate was analyzed by Secondary Ion Mass spectrometry (SIMS). In addition, the longitudinal distribution trend of I and II impurities and VI and VII impurities in the Hg1-xCdxTe epitaxial layer and CdZnTe substrate was also analyzed by SIMS. It was found that the transition region between the substrate and the epitaxial layer can absorb the impurities. This result is of significance to the improvement of detectors in performance.

Abstract:In the mass production of InSb infrared detectors, it is found that the micro-stress in an Au electrode thin-film can result in the performance degradation of InSb devices. Through experimental design, the effect of Au electrode thin-film on the detectivity, sensitivity and reliability of InSb chips is verified. The mechanism and recoverability of the micro-stress in the Au electrode thin film are studied and a way to control and optimize the micro-stress is proposed. The research has laid the theoretical and experimental basis for the improvement of the performance and reliability of infrared detectors in the aspects of process and device structure.

Abstract:Cloud contamination may affect the simulation of the radiation of a cloud area and hence results in the discard of a large number of satellite data. According to the current application of the Community Radiative Transfer Model (CRTM) and the principle of infrared remote sensing, the radiation transfer module in the CRTM is modified and a CRTM cloud mode which can simulate the infrared radiation of cloud areas is proposed. The CRTM cloud mode is used to simulate the channel brightness temperature of the Atmospheric Infrared Sounder (AIRS). The sensitivity of the new parameters added to the cloud mode is analyzed. The results show that with the decline of channel altitude, the atmosphere which contributes greatly to the radiation received by the satellite decline too. The altitude where the large deviation area locates is becoming lower and lower. In the large deviation area, the deviation increases with the increasing of cloud amount. When the sky is fully covered by cloud, the deviation reaches its maximum. When cloud amount becomes larger, the vertical variation of the temperature profile inputted may cause the radiation emitted by cloud top to form the same vertical distribution. This is in accordance with the vertical variation occurred when the brightness temperature simulated by the CRTM cloud mode increases with the rising of cloud top. The brightness temperature value simulated by the CRTM cloud mode is more sensitive to the newly added parameters of cloud amount and cloud top altitude. This accords with the law of atmospheric infrared radiation transfer.

Abstract:Because of excellent infrared stealth performance and mobility, armed helicopters can break through terminal air defense systems and play a huge role in modern warfare. Taking an Apache armed helicopter as an example, an infrared radiation model is established on the basis of a fluid dynamics software. The infrared radiation characteristics of the helicopter flying at low altitude are analyzed. For the main operation wavebands of terminal infrared air defense missiles, their infrared radiation intensity values in the middle infrared waveband from 3 to 5 μm and in the long infrared waveband from 8 to 12 μm are calculated respectively. Finally, on this basis, the main threat of an armed helicopter to terminal infrared air defense is analyzed and several methods for improving the detection and anti-interference ability of armed helicopters are discussed.

Abstract:According to the feature that the resolution of the Acousto-Optical Tunable Filter (AOTF) spectral measurement system changes with the diffraction wavelength, a method using deconvolution algorithm to improve the spectral resolution capability of AOTF spectrometers is studied. Combining with the distribution of spectral resolution, nonlinear coordination transformation is performed in the spectral range so as to keep a same transfer function over the entire spectral range. Then, the nonlinear iterative deconvolution method and Fourier self-deconvolution are used to process the line spectral data acquired by the Fourier spectral system for resolution improvement. The simulation results are restored in resolution to a great extent and the original low resolution information which is lost because of low resolution is recovered.

Abstract:Laser directional jamming is the most effective way to countermeasure infrared imaging seekers. Therefore, the research on laser directional jamming to infrared imaging seekers is of significance. There are many factors affecting the jamming effectiveness of mid-wave infrared laser directional jamming. Among those factors, the power density of laser falling on a target is the important affection factor. In view of the attenuation function of atmospheric transmission for mid-wave infrared laser, the optical gain of seeker''s optical system to the mid-wave infrared laser and the variation of jamming laser spot size with distance, the relationships of atmospheric transmission of mid-wave infrared laser with atmospheric visibility and transmission distance are studied. The affection of atmospheric turbulence on the total divergence angle of laser transmission is analyzed. The directional jamming model of 3.8 μm laser for infrared imaging seekers is obtained. The relationship curves among the power density of laser falling on a target, the atmospheric visibility, the atmospheric turbulence intensity and the jamming distance are drawn. The model is verified in outdoor. The result shows that it has an error greater than one order of magnitude which mainly results from the calculation error of far field laser spot and atmospheric transmittance. This research is of a certain referential value to the development of jamming equipment.

Abstract:With the increasing development of computer vision technology in the application field of image processing and pattern recognition, the detection of moving human targets has become a hot focus attracting more attention gradually. An improved moving human target detection algorithm is proposed. The background is extracted in an image by a median method. Then, the moving target region is obtained by combining the background subtraction with the frame difference in the processing of the image. The experimental results show that the algorithm can overcome the defect brought by a single algorithm. It has a higher accuracy and meets the real-time requirements in engineering application. Since the algorithm is simple and effective, it is suitable for embedded platforms.

Abstract:In the current single-frame image threshold segmentation, the segmentation is susceptible to mutations, the background segmentation is not obvious and the segmentation effectiveness is poor. To solve these problems, an automatic threshold segmentation method based on infrared image frame association is proposed. Firstly, the automatic threshold segmentation method is used to segment a single-frame image simply. Secondly, the image is processed group by group according to the frame-related information. Then, the weights are assigned to each frame. Finally, the segmentation threshold of each frame is determined to improve the anti-interference and segmentation effectiveness. The validity and feasibility of the method are verified through theoretical analysis and experimental simulation. Compared with other algorithms, the proposed method is stronger in anti-interference ability. It can segment the target image clearly from the background and has better segmentation effectiveness and applicability.