Abstract:The modeling and simulation of various effects of infrared imaging sensor systems are not only helpful to the actual analysis, test and evaluation of infrared imaging weapon systems, but also can provide the basis for the performance analysis and design of infrared sensors. Therefore, they are of importance to military and economy. The current status of effect modeling and simulation of infrared imaging sensors are analyzed. Several typical infrared sensor models are described in detail. Finally, some ideas are proposed to the effect modeling and simulation of infrared sensors.

Abstract:Because of the advantages of high resolution etc, Fourier transform spectrometers have been used as a new generation of atmospheric sounders. Such a spectrometer will acquire a very large quantity of data. To reduce the amount of the data to be transmitted, the data should be processed on board. One of the methods is use of in-orbit spectral recovery. Since there exists phase difference in the interferograms sampled by non zero optical path difference sampling, the complex spectra obtained by using Fourier transformation should be corrected in phase so as to generate the real spectra.The Field-Programmable Gate Array (FPGA) is a promising on-board data processing hardware platform. Phase error sources and phase correction methods are presented. The square root method is suitable for a FPGA to implement. In view of the problem that a lot of hardware resources are needed and poor precision is obtained when the square root is calculated by using the traditional method, a Coordinate Rotation Digital Computer (CORDIC) algorithm is proposed for the calculation of complex modulus spectrum and phase angle. The FPGA implementation structure of the CORDIC algorithm is mainly discussed, and the required precision, speed and hardware resources are analyzed. The results show that the phase and modulus of complex spectra are good in precision and speed when the CORDIC algorithm is used. Less hardware resources are needed.

Abstract:The athermalization of a Schmidt optical system in the temperature range from -60℃ to 60℃ is designed by using wavefront coding. Taking a classical Schmidt system with a field angle of ±4° and a relative aperture of 1/2 as an object to be studied, a cubic surface is used as the wavefront coding surface. Under the constraint condition of a transfer function greater than zero, the parameters of the wavefront coding surface are optimized in a defocus range as large as possible. A Schmidt system with a defocus amount up to ±0.6 mm is obtained. Its focal depth is extended by a factor of 20 compared with that of the classical Schmidt system. Its defocused spot and transfer function data at different temperatures are analyzed. The result shows that this Schmidt system with wavefront coding has good adaptability in the temperature range from -60℃ to 60℃. Its optical performance is stable, so it facilitates the subsequent image restoration.

Abstract:As a core device of a target detection and imaging system, an infrared detector assembly's space resolution may directly affect the imaging quality of the detection system. Usually, the Modulation Transfer Function (MTF) is used to evaluate the spatial resolution. However, both electric crosstalk and optical crosstalk of a detector assembly are the main factors affecting the MTF. A phase-locked system is used to measure the electric crosstalk of the infrared detector assembly while an infrared micron-spot test system is used to measure the Line Spread Function (LSF) of the assembly so as to evaluate its optical crosstalk. The measurement result shows that the optical crosstalk of the 11.5-12.5 μm waveband detector is obviously greater than that of the 8.0-9.0 μm waveband detector. Finally, the measurement result is analyzed. The analysis result provides a reference for the optical crosstalk design of the infrared detector assembly.

Abstract:An optical method for revealing the handwriting mark covered by carbon ink is proposed. It can provide a technical support for the finding of cases. An infrared imaging spectrometer is used to collect a set of infrared spectral images of the handwriting mark covered by carbon ink. Through the analysis and processing of the collected infrared images by a spectral feature matching method, the handwriting mark covered by carbon ink is revealed clearly. The experimental result shows that the spectral feature matching method based on infrared spectral imaging is an effective optical method for revealing handwriting marks covered by carbon ink.

Abstract:A vanadium metal thin film is prepared by using magnetron sputtering at room temperature. Then, the film is annealed in a suitable oxide atmosphere. Finally, a high quality vanadium dioxide thin film with phase transition is prepared on an amorphous glass substrate. The X-Ray Diffraction (XRD) test result shows that the main component of the prepared film is vanadium dioxide. The Scanning Electron Microscope (SEM) test result shows that the prepared film is well crystallized and distributed. The film has its infrared transmittance of 67% at 2400 nm wavelength at room temperature and has its infrared transmittance of 9% at the same wavelength at room temperature. The transmittance difference is 58%. Therefore, it has a good infrared transmittance adjustment ability. In addition, the difference between the optical transition and the electric transition of the film is analyzed. It is found that its electric transition temperature is 4.7℃ higher than its optical transition temperature. This method is suitable to prepare large area vanadium dioxide films and is of significance to the research and application of smart windows.

Abstract:Because active millimeter-wave can penetrate through cloth and plastic materials, three-dimensional holographic images of hidden dangerous goods such as metals, drugs, explosive and knives can be acquired. Compared with a X-ray inspection system, the active millimeter-wave has almost no radiation and does not do harm to biological tissue. At present, more and more metal detectors and X-ray imagers have been replaced by millimeter-wave imaging equipment in Europe and U.S.. With the rising of China's national influence, the active millimeter-wave imaging technology will have a broad application prospect in the field of public safety.

Abstract:An optical distribution design method based on azimuth modulation is put forward. Model OSLON SX high power Light Emitted Diodes (LED) are chosen as a light source. An optical model of a 4×4 LED array is built with 16 LEDs. The illumination distribution on the receiving surface is controlled by changing the azimuth of each row of LEDs. The research result show that the illumination distribution on the receiving surface is most uniform when the upper and lower portions of the LED array tilt at an angle of ±30° respectively.

Abstract:Thermal radiation is one of the main hazard characteristics of oil depot fire and the temperature field is the direct representation of the thermal radiation. Therefore, rapid and effective monitoring of the temperature field information is the best way to quickly acquire dynamic fire information. It is of significance to the improvement of emergent oil depot fire accident monitoring and fast response ability, the maintenance of people's life, property and safety, the protection of ecological environment and the great reduction of economic losses etc. On the basis of the research progress in ground surface temperature inversion methods at home and abroad, an oil depot fire temperature field information extraction model based on thermal infrared spectral and ground-based sensor data is established. By designing simulation experiments, the ground surface temperature conditions in the test side and its surrounding areas are inversed successfully. The result shows that this model can be used to quickly and effectively inverse the temperature field information of the area in which oil depot fire accident happened.

Abstract:With the development of infrared imaging guided systems, higher requirements are put forward to the precision and real-time performance of guided tracking algorithms. Currently, guided systems have been required to output tracking results within 20 ms. Although some tracking algorithms have good tracking effectiveness, they can not output their tracking results in real time. Since the classical correlating tracking algorithm is mainly based on pixel gray-level features, the tracking point drift problem caused by the rotation, expansion and translation of the target in the process of tracking can not be solved. To solve the problem that the classical correlation tracking algorithm can not operate stably when the image is rotating and the tracking point drift problem present when the target image is expanding quickly, the invariable moment features of images are studied. The features of rotation-scale-translation invariance of images are used to choose the suitable invariant moment features for tracking. The tracking algorithm is designed by using the multiplication correlating function and the template update function based on correlation coefficient. The problem that the infrared target of which the size and shape are changed in complex and yawp environment can not be tracked stably is solved.