Study Of Imaging System Of Light Thermal Weapon Sight

In the dark environment, the visual range of light thermal weapon sight is betweenthat of night light weapon sight and cooled thermal weapon sight, and it is easily to bebrought to anywhere, so the best selection at mid-range is uncooled light thermal weaponsight. In military, there is more and more attention on light thermal weapon sight. In thosewest developed countries, the application of uncooled thermal imaging, as a militaryresearch, was started 20 years ago, and now, light thermal weapon sight have been used inwar field. On the contrast, the development level of thermal weapon sight in domestic ismuch lower. Firstly, the manufacture technology of uneooled focal plane array (FPA) is notfound in domestic. And the second is that the imaging component of light thermal weaponsight has been developed by some civilian enterprises, so that the system performance cannot be improved in nature. Basing on these reasons, supported by certain sponsor, how todesign of imaging component, how to test the performance of light weapon thermal sight atlow and high temperature and how to research of aid model for aim were introduced in thispaper. In a word, the main work in this paper is to make a-Si uncooled thermal imagingsystem used in light weapon thermal sight.Chapter one, the light weapon sight technology in day light and night light wasintroduced, showing that light thermal weapon sight was the direction. The main work ofthis paper was introduced also.Chapter two, the theory of uncooled FPA was researched, a-Si micro-bolometer wasanalyzed from response principle, material, read-out circuit, calorifics structure, biasvoltage and noise in great detail, the performance was researched and rules were putforward to guide the development of imaging component. Introduction about theory andalgorithm of un-uniformity correcting for FPA could be found in this paper, the currentalgorithm in imaging system was two-point correction, and other algorithms would behelpful for improving the function of software.Chapter three, light thermal weapon sight imaging system was designed. On theground of requirement of thermal weapon sight, the aspherie infrared lens was designed.The imaging component with stable performance at room temperature was developed. Thefunctions of the component include driving uncooled FPA, two-point un-uniformitycorrection, statistics of gray histogram, auto gain controlling by keyboard, cross,eompostive video, communication with PC. With DSP and FPGA as the main processors,the TEC circuit, waterline design and bad pixels replacing were the features of imaging component in stable and real-time performance. OLED was used as the display device, itwould meet the requirement of light thermal weapon sight in temperature and volume.Chapter four, the temperature performance of uncooled FPA was analyzed in theory.The relation of temperatures, image quality and power consumption were researched. Bytheory analysis and application requirement at wide temperature range, the imaging circuitwas optimized in un=uniformity correction and inner temperature controlling. The low andhigh temperature test was designed and carried out. Through the test and compare with thatof before, the performance in image quality was improved and power consumption wasdecreased clearly. At last, the temperature drift of uncooled FPA was consulted and the newun=uniformity correction method was put forward to resolve the problem fromenvironment temperature variety.Chapter five, being from feature of human eyes, aid model for aim of light thermalweapon sight was researched, the notion of little view window was brought forward, theprocedure was given. A new image enhancement algorithm in little view window wasintroduced. Target detection and orientation was used to estimate the distance of target,moving speed and direction. As a new method, based on the density and lightness to detectand orient target, was put forward because the detecting probability and real-timeperformance could be improved with it. The test devices for software were set up, andsome test was carried out. The purpose of these researches was resolving the contradictionbetween real-time performance and estimation precision.Chapter six, the whole dissertation and enumerated the work that has been done tocomplete the dissertation and moreover was summarized. It pointed out the innovationwork of dissertation and put forward the problems that were need to accomplish in thefuture.