Abstract:Infrared photoelectric detectors have shown their versatility in military, civilian and scientific research applications. Because of many advantages, the detector material HgCdTe has played a vital role in the development of infrared photoelectric detectors. Up to now, it is still the best choice for many applications. First, the SWaP3 concept proposed for the new generation of infrared detectors is analyzed. Then, the HgCdTe materials qualified for the third generation of infrared focal plane arrays (FPA) are presented in brief. Finally, the research progress of large format array devices, very long wavelength devices, high operation temperature (HOT) devices, hyper-spectral devices, dual-band devices and avalanche photoelectric diodes (APD) is summarized.

Abstract:With the development of infrared imaging guided weapons, the performance of the infrared target simulators for simulation experiment is improved. Now, the infrared polarization imaging technology is becoming mature and the detection systems and guided weapon based on infrared polarization imaging are also being developed. According to the polarization generation and modulation technologies, several infrared polarization imaging simulation systems which are able to provide polarization information from targets to the detection systems and guided weapon based on polarization imaging are discussed.

Abstract:According to the requirements of THz imaging detection, an optical system suitable for the THz waveband is designed. The optical system has a focal length of 50 mm, a F number of 1, an operation waveband from 50 μm to 100 μm and a full field of view of 11.9°. Its receiver is an uncooled IRM160A infrared detector. In the system, a coaxial structure consisted of three spherical lenses and a piece of glass for protecting a CCD is used. A new material Topas COC is used. In addition, to meet the requirements of simplicity, low weight and low cost, an aspheric surface is also introduced. The design result shows that at a cut-off frequency of 10 cy/mm, the optical system has a modulation transfer function close to the diffraction limited curve. In each field of view, the RMS radii of the spot diagrams are far less than the airy disk radius. Its imaging quality is good. So it can meet the overall design requirements of a THz optical system.

Abstract:High repetition frequency laser jamming is a highly effective jamming technology in the field of opto-electronic countermeasure. Starting from the principle of high repetition frequency laser, the decrease of the signal-to-noise ratio (SNR) of the receiving system in a laser seeker caused by jamming laser power is analyzed theoretically and calculated numerically, and hence the previous overall understanding of high repetition frequency laser jamming is clarified. The numerical calculation result shows that for a missile guidance system, its SNR may be reduced with the increase of jamming laser power at a given distance and may be reduced with the increase of the target distance in the case of same jamming laser power. When the target is at the distance of 6000 m and the jamming laser power is greater than 0.4 W, the SNR of the missile guidance system may be reduced to less than 1. At this time, the missile guidance system can not detect the target echo signals from different noises, and so the target to be attacked can be protected effectively.

Abstract:A neural network model for estimating the atmospheric transmittance of infrared radiation is established on the basis of the experimental temperature data of a blackbody measured at fixed points. After the temperature of a blackbody is measured at different distances, a BP network is introduced to adaptively learn the underlying regulations of the measured data. The functional relationship between the current measuring distance and the measured temperature is set up. The actual temperature of the target is calculated accurately. The simulation result shows that the built BP network can learn the sample information effectively and the nonlinear atmospheric transmittance model established can solve the problems such as the difficult calculation of atmospheric transmittance of infrared radiation due to the complicated influences.

Abstract:A grey level model of small targets in the spatial domain is established on the basis of the point spread theory in target imaging. The basic characteristics of the target, background and noise are analyzed. After the open and close morphologic operation is implemented, the grey level variation in each pixel position is derived. Thus, the potential target areas are determined. The multi-orientation and multi-degree gradient of each potential area are studied. The detection of small targets is implemented in a single frame. The result shows that this method can effectively suppress uneven background clutter, enhance target signals and improve the detection of bright and dark small targets in a single frame. For an image with a signal-to-noise ratio (SNR) of 0.89, a SNR gain of 34.74 can be obtained.

Abstract:To calculate the temperature field on target surface conveniently during infrared imaging simulation, a method for calculating the radiation transfer coefficient on target surface based on accessible radiant energy is proposed. The formula method, Monte Carlo method, and accessible radiant energy calculation method are respectively used to calculate the radiation transfer coefficient between two vertical surfaces and that between two parallel surface models. The calculations are verified by simulation. The result shows that the calculation efficiency of the accessible radiant energy calculation method is improved greatly compared with the formula method and the Monte Carlo method, while its calculation accuracy is ensured to meet the requirements.