Abstract:Infrared detection systems usually need close-packed detectors in order to increase their spatial resolution.The crosstalk between individual elements in a focal plane array (FPA) occurs when the infrared photons incident on a particular detector's active area in the array generate signals in another detector. The resolution performance of a FPA may be limited by the crosstalk. The dominant form of the crosstalk occurring in a high performance photovoltaic array is associated with the photogenerated carriers diffusing laterally between adjacent elements within the FPA. Starting from basic concepts, the research progress and the understanding and comprehension of crosstalk are presented.

Abstract:To interfere with an infrared focal plane array (IRFPA) detector effectively, it is necessary to analyze the response of the device under the irradiation of different wavelength lasers. Four lasers with different wavelengths are used in an irradiation experiment. The experimental result shows that the detection elements in the device can reach their saturation states easily and the device's response is in agreement with its spectral response curve. This has verified the relationship between the interference effect and the spectral response curve and provided the experimental basis for the middle infrared laser interference. Finally, the response mechanism of the infrared focal plane device to the laser irradiation in a given waveband is analyzed in brief.

Abstract:The measurement principle and method of the bidirectional reflectance distribution function (BRDF) are presented. A setup for measuring BRDF is built. The setup can be used to measure the BRDF in both the visible band and the infrared band. In the visible band, a tungsten halogen lamp is used as a light source and a fiber optical spectrometer is used as an optical receiver. The BRDF is measured at a wavelength interval of 10 nm. In the infrared band, a silicon carbide material is used as an infrared source and a pyroelectric detector is used as an optical receiver. The BRDF of a sample is measured through indirect calibration of a standard plate. The measurement repeatability of BRDF is less than 1.5 percent in the visible band, equal to or less than 2.5 percent in the range from 3 μm to 5 μm and less than or equal to 3.0 percent in the range from 8 μm to 12 μm. The experimental result shows that the BRDF measurement setup is highly effective.

Abstract:The variational assimilation channel brightness temperature of the Infrared Atmospheric Sounder (IRAS) onboard FY-3B weather satellite requires its observation simulation deviation to satisfy Gaussian distribution. Because the deviations contained in satellite data processing and numerical forecast modes do not follow Gaussian distribution, it is necessary to correct them. First, the preliminary quality control such as cloud detection is performed for the data from IRAS. After the brightness temperatures in 20 channels of IRAS are counted, it is found that the scanning deviation is symmetry at nadir. Finally, both the scanning deviation and the air mass deviation are corrected. The result shows that after correction, the absolute deviation values in top channels 1, 10 and near ground channel 14 are increased. The deviations and standard deviations in water vapor channel 13 and ground channel 20 are increased. The mean brightness temperature observation deviation in other 15 channels are reduced from 1.04 K to 0.30 K. Their corresponding standard deviations are reduced from 2.28 K to 1.99 K. The deviation probability distribution is more Guassian.

Abstract:Using a CFD flow simulation software to analyze the aerodynamic heating of an anti-ship missile cruising at a high speed is a new method for studying skin radiation in recent years. The infrared radiation characteristics of an anti-ship missile in the atmosphere background are obtained by using both a CFD simulation software and a MODTRAN software to analyze the infrared radiation characteristics of the missile when it is cruising at a high speed.

Abstract:On the assumption of single spherical frog droplets, the motion and evaporation characteristics of frog droplets under the coupled effect of thermal radiation and forced convection are studied by establishing a model for the motion and evaporation of frog droplets. It is found that the main factors which have influences on the frog droplet lifetime in outdoor environment are ambient humidity and the initial diameter of frog droplets. The influences of thermal radiation and forced convection are negligible. The thermal radiation can cause the temperature of frog droplets to increase, even above the ambient temperature. The temperature of frog droplets may firstly increase and then decrease. The influence of forced convection on the temperature of frog droplets is negligible. The larger initial frog droplet diameter is helpful to the formation of dense frog. However, the oversize diameter may cause the lifetime of frog droplets to decrease due to their sedimentation. So there exists an optimum initial diameter for frog droplets.

Abstract:Surface-type infrared jamming is one of the new countermoves to infrared imaging guiding missiles. The operation process and target identification of an infrared imaging guiding missile are analyzed. The use of surface-type infrared jamming and the evaluation norm of its jamming effectiveness are studied respectively in both target identification phase and target tracking phase when the infrared imaging homing head is jammed. The ability of the surface-type infrared jamming to countermeasure infrared imaging guidance is evaluated. By taking the tracking state, tracking error and miss-distance as the basis, the evaluation norm implements the quantitative evaluation of the jamming effectiveness of the surface-type infrared jamming after the success rate of jamming is counted. This evaluation method is simple and reasonable. Its evaluation result is objective and effective.

Abstract:The smoke dust generated on the scene of fire is analyzed and simulated by using an aerosol generator. The standards for the smoke density measuring systems used in smoke detectors are listed. A fire smoke density measuring system based on infrared technology is proposed. The information acquisition unit of the measuring system consists of an infrared transmitting tube and an infrared receive tube. First, the smoke information acquired by the acquisition unit is filtered, amplified and sent to an analog-digital converter for digital processing. Then, the digital signals are sampled and discriminated by a MCU information processing system in real time. Finally, the obtained data are displayed or transmitted to the host computer through a network bus. The system has the features such as simple structure, easy mounting and higher accuracy.

Abstract:The infrared spectral characteristics of waxed pear were studied by using a CCD array spectrometer. It was found that in the range from 655 nm to 660 nm, the waxed pear had an absorption peak while the pear which was not waxed did not have the absorption peak. In the range from 610 nm to 620 nm, the infrared spectral absorption peak of the paraffined pear was comparable to that of the pear which was not waxed. However, the infrared spectral absorption peak of the pear coated with fruit wax was much lower than that of the pear which was not waxed. The result showed that the infrared spectroscopy had a particular feasibility in the detection of waxed pear. It also provided a reference for the further study of intelligent nondestructive waxed pear detection technologies.