Криміналістична техніка та методика
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Item Дальність дії тепловізора та чинники, які на неї впливають. ACTION RADIUS OF THERMAL IMAGER AND FACTORS AFFECTING IT(2018) Неня, О.В.; Nenia, O.V.Several technical and optical factors, observation conditions that affect the range (detection distance of thermal radiation) of thermal grids, including military ones, which are simultaneously the main criteria for their selection, are considered. Such concepts as “detection range”, “recognition,” and “identification,” characterizing different degrees of the vision of the target (object) with a thermal imager, are highlighted. Attention is drawn to a probabilistic index – the Johnson criterion, which, although it is probabilistic, since it depends on a number of random factors, is however the most universal and widespread one. It gives a forecast of the efficiency of the thermal imaging camera for solving a specific problem in certain conditions. Among the important factors affecting the range of action of thermal imagers, the thermal transparency of the atmosphere is considered. Since thermal radiation weakens due to the absorption of gas by molecules, dust, aerosols, etc., an important component of the effective operation of thermal imagers is the so-called “transparency win- dows” – spectral ranges convenient for their work. Among the technical factors that significantly affect the range of the thermal imager, paper details the resolution of its photodetector (or matrix), the dimensions of which (the number of sensitive elements (pixels) located horizontally and vertically) determine the final image clarity. An important parameter that significantly affects the range of a thermal imager is the focal length of the objective lens (lens) of the thermal imager, collects and focuses IR radiation on the matrix in accordance with the temperature distribution of the observed object. The radius of action of the thermal imager depends on the focal length of the lens, which also affects the so- called instantaneous sector of the system overview (IFoV) – the angular resolution of the system. The value of the focal length and angular resolution are inversely proportional, which is enshrined in the paper by mathematical calculations. Speaking about the focal length of the lens, we should not forget about the sharpness of the displayed space, which depends on the lens aperture, and which characterizes the degree of attenuation by the lens (lens system) of the infrared imager from the object of observation. Paper concluded that determining the range of the thermal imager, as a function of multiple variables, requires a fairly complex simulation.