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In this study, a method based on ejector technology is proposed to effectively suppress the infrared radiation associated with the exhaust gas of special vehicles such as tanks, armored vehicles, and missile carriers. These vehicles emit exhaust gases at very high temperatures. First, a mathematical model of the exhaust pipe was established for the exhaust system of a certain type of special vehicle. Then, the 3-D flow field outside the exhaust pipe was numerically simulated using FLUENT 6.3 software. Thus, the temperature, pressure, and density of the exhaust-gas-flow field before and after adopting the proposed ejector technique were obtained. Second, the statistical narrowband model based on the Lorentzian profile was used to determine the average absorption coefficient of a narrow band. Then, the finite volume method was used to solve the radiation transfer equation in the gaseous medium. Finally, the spectral radiation brightness and mid-infrared radiation intensity distribution of the exhaust gas before and after adopting the ejector technique were obtained. Results show that the proposed method considerably decreased the infrared radiation intensity of the exhaust gas by approximately 70%. Thus, using the proposed ejector technology, the infrared radiation associated with the exhaust system of special vehicles can be effectively suppressed.

The infrared radiation characteristics of oil storage tanks are an important basis for the detection and identification of oil tanks. The study of the infrared radiation characteristics of oil tanks is of great significance to the realization of infrared protection and stealth of oil tanks. This paper takes oil tanks as the research object, establishes a theoretical calculation model of the tank surface temperature field and a one-dimensional heat balance equation, and obtains the temperature distribution of the tank surface at various times. On this basis, the infrared radiation characteristics of the oil tank are further calculated, discussed and analyzed.

Compared with the image target detection system of single infrared band , the target detection system of double infrared band image fusion has higher performance. However, the target detection of dual band image fusion requires higher real-time and stability of data processing. Aiming at the characteristics of large amount of data and complex algorithm of dual band image fusion target detection system, a dual band infrared image target detection system based on DSP+FPGA architecture is designed. This system has the advantage that DSP is good at realizing complex image processing algorithms and FPGA has high speed parallel processing capacity. This design meets the system's requirements for real time and stability.

The intensity distribution of the whole arc is not uniform in the discharge process of short-arc xenon lamp. Generally, the intensity of the arc is the highest at 0.07×L (L is polar distance) away from the cathode, forming a cathode spot with great brightness. Therefore, short-arc xenon lamp can be regarded as a point source of high brightness, and short-arc xenon lamp is an ideal concentrating light source, which is similar to sunlight in intensity and collimation. Xenon lamp has the characteristics of high radiation power, small spot, high brightness, good stability and instantaneous start-up. The luminous point can be made very small, and the positioning accuracy is high, so it is easy to realize directional reflection. The spectral energy distribution of short arc xenon lamp is close to that of blackbody radiation. The short-arc xenon lamp can be used as an ideal point source for military searchlight, solar simulator and optical experiment. Parabolic reflector is an axisymmetric quadric reflector. It can be used as a reflector for directional xenon lamp because it has equal optical path to the object point on the infinite far axis. According to the characteristics of parabolic reflector, the model of directional xenon lamp is established by TRACEPRO software, and the effects of focal length, aperture, inclusive angle and axial defocusing of directional xenon lamp on illuminance are simulated and analyzed.

Exhaust system is the most important infrared radiation source of a long-endurance UAV and the shape of the nozzle contribute to the infrared radiation characteristics of exhaust system. This paper built a 2-D nozzle and use ANSYS14.5 simulated the temperature filed of the plume. And then, spectral infrared radiation characteristics of the plume were obtained by the single band C-G approximation method. Finally, the infrared radiation intensity distribution of the exhaust system of the 2-D nozzle in different planes is obtained. The results show: The infrared radiation of the plume in wide side detection surface is far greater than the narrow side; The infrared radiation of the nozzle in wide side detection surface is smaller than the narrow side; The infrared radiation of the exhaust system in wide side detection surface is smaller than the narrow side. The results maybe contribute to the further study of the infrared radiation characteristics of the long-endurance UAV.

For mastery of infrared radiation characteristics and flow field of exhaust plume of twin engine nozzles, first, a physical model of the double rectangular nozzles is established with the Gambit, and the mathematical model of flow field is determined. Secondly, software Fluent6.3 is used to simulated the 3-D exterior flow field of the twin engine nozzles, and the datum of flow field, such as temperature, pressure and density, are obtained. Finally, based on the plume temperature, the exhaust plume space is divided. The exhaust plume is equivalent to a gray-body. A calculating model of the plume infrared radiation is established, and the plume infrared radiation characteristics are calculated by the software MATLAB, then the spatial distribution curves are drawn. The result improves that with the height increasing the temperature, press and infrared radiant intensity diminish. Compared with engine afterburning condition, temperature and infrared radiant intensity increases and press has no obvious change.

Plume is the main infrared source of a long-endurance UAV, and its infrared radiation numerical calculation is very important for calculating the infrared characteristcs of the whole UAV. This paper built the geometrical model of the flow field structure of UAV plume by analyzing the characteristcs of the flow structure. And, The temperaturre field distribution of the UAV plume was calculated based on the eddy current propagation theory. And then, spectral infrared radiation characteristics of the UAV plume at 2-5μm were obtained by the single band C-G approximation method. The results show that the temperature in the core area of the UAV plume is higher , and the infared radiation characteristics are stable and obvious. The infrared radiation energy of the plume mainly ditributed at the infrared wavelength of 2.7μm and 4.5μm,which is in accordance with the actual situation. The results maybe contribute to the further study of the infrared radiation characteristics of the long-endurance UAV.

For mastery of infrared radiation spectral characteristics and intensity distribution of exhaust plume of an axial-symmetrical nozzle, this paper used software Fluent6.3 to simulate the 3-D exterior flow field of the axial-symmetrical nozzle, and obtained the data of the flow field such as temperature, pressure and density, and established the columniform area of computing infrared radiation according to the characteristic of the axial-symmetrical nozzle plume. Then by the finite volumetric method (FVM) and the narrow band model of gases infrared radiation, the spectral characteristic and the total intensity distribution in 3~5μm of exhaust plume infrared radiant were calculated. The results show that the infrared radiation intensity distribution is axial-symmetrical, and the infrared radiation intensity is the feeblest in axial direction and is stronger in π/6～π/3 direction, meanwhile, two peaks of plume infrared radiation emerge in 2.7μm and 4.3μm, and the infrared detector by 4.3μm is in favor of detecting an aircraft.

Interference mechanism of laser disturbing infrared detector is analyzed. The disturbing grade was separated into four levels according to interference effect. The levels are saturation, melting, vaporization and plasma. The responsivity of a detector will drop and it can’t work effectively when it was saturated. Its performance wills recovery when the interference disappeared. Melting, Vaporization and plasma will lead to permanent damage. The main damage to detector is thermal damage for induced laser. The reason is that the detector will melt or evaporate when it absorbed the energy of induced laser. For HgCdTe detector, the damage appeared as Hg precipitation. It appeared as In exfoliated from welding outlet line of HgCdTe crystal or HgCdTe melting when the temperature of detector is higher. Since Vanadium Oxide has reversible transformation characteristic between semi-conductor, metal and insulator, it can be used to protect detector from laser damage. Vanadium Oxide can be made as thin film coatings on optical system to protect the detector. the phase transformation point temperature of VO 2 is 68°C,a few doping method can decrease the transformation temperature. These mean that less energy can make VO 2 film’s temperature increase to transformation point. VO 2 film protecting HgCdTe detector was used as an example to estimate the protection effect. For an HgCdTe detector, its responsivity will drop two orders of magnitude when its temperature raises 70K. This case be regard as that the detector was disturbed. When a CO 2 pulsed laser beam with 0.1μ s∼10μs pulse width was incidence an HgCdTe detector, its heat conduction depth is 0.32∼3.2μm and its thermal diffusion can be ignored. The damage energy density threshold value is E in =1.55J/cm 2 . When CO 2 pulsed laser beam incidence the detector through certain thickness VO 2 film, the VO 2 film will has transformed from semiconductor state to metallic state before the laser beam damage the detector. The energy of the laser beam will be total reflected. VO 2 can be used as an intelligent preventer to protect detector against laser.

A new face recognition system was proposed, which used active near infrared imaging system (ANIRIS) as face images acquisition equipment, used kernel discriminative common vector (KDCV) as the feature extraction algorithm and used neural network as the recognition method. The ANIRIS was established by 40 NIR LEDs which used as active light source and a HWB800-IR-80 near infrared filter which used together with CCD camera to serve as the imaging detector. Its function of reducing the influence of varying illuminations to recognition rate was discussed. The KDCV feature extraction and neural network recognition parts were realized by Matlab programming. The experiments on HITSZ Lab2 face database and self-built face database show that the average recognition rate reached more than 95%, proving the effectiveness of proposed system.

For accurate knowledge of the impact of ejector technique on infrared radiation of the plume, the physical model of the rectangular nozzle is established. The 3-D flow field outside the rectangular nozzle is simulated by numerical method with software Fluent6.3 pre and post the application of ejector technique, then the data of the flow fields, such as temperature, pressure and density and so on, are obtained, and according to the characteristic of the rectangular nozzle plume the computational domain of infrared radiation was established. This paper uses Lorentz linear statistical narrow-band model to calculate the mean absorption coefficient of the plume in the narrow band. Then it uses Finite Volume Method(FVM) to solve the radiation transmission equations in gas medium, and it obtains the total intensity distribution in 3~5μm of the plume radiation pre and post the application of ejector technique. The results shows that the infrared radiant of the rectangular nozzle decreases significantly by 80% after the application of ejector technique.

The IR scene simulation technique is an effective method to test the responsivity, the precision and the anti-interference capability of the IR detector during its research and development; thus the technique may reduce the cost and research time. Currently, the IR scene simulation technique based on MOS-Resistance arrays is one of the most popular IR scene simulation techniques. However, resistance arrays can only be heated, but not refrigerated. Moreover, other simulation techniques also have the problem of one-direction IR scene simulation. In this paper, the IR simulation mechanism is studied in detail. According to the analysis of the characteristic of the semiconductor device based on the Peltier effect , the bidirectional IR scene simulation technique based on semiconductor refrigeration device with the Peltier effect and the computer controlling technology is put forward. Moreover, a prototype machine is designed ,and the shortcoming of the IR scene simulation system based on MOS-Resistance arrays which can only be heated is avoided. Finally, the performance of the prototype machine is tested by experiments. The results show that the system can realize bidirectional IR scene simulation perfectly by the means of increasing and reducing the temperature.

The technology of generating infrared image based on electric heating film technology by its resistance per unit area was studied. A Lifgt-off-road vehicle was used as an object to be simulated. An infrared thermograph was used to photography the light-off-road vehicle from a specific corner. As a result several infrared images of the light-off-road vehicle were obtained and the thermal distribution of the vehicle was also obtained at the same time. A matlab program was used to process the image. The image was divided into several areas according to its grey level. Each area has its own temperature range. The average temperature of each area was calculated. A thermal balance equation was established according to the average temperature of each area and the environment temperature. By solving these equations, the radiant existances of these areas were gotten. The heating power per unit area of these areas was calculated. The electric heating film was preparation accordingly. The power was applied on the film and the infrared thermograph was used to observe it. The infrared image of the film has a high similarity with the true light-off-road vehicle's.