Estimate The Distance Of The Infrared Imaging System

In recent years, infrared imaging system (IRIS) has been widely applied in many application fields such as military, medical and industry fields etc, So system evaluation is of great importance to theoretical and practical applications. On the basis of static field performance model, we have designed models to calculate the view range of infrared imaging systems. The view range is a fundamental factor to design infrared imaging systems.The factors that affect the view range of IRIS are discussed in this paper. View range is mostly influenced by three factors: feature of target and background, the atmospheric attenuation and the performance of IRIS. Among these factors, the atmosphere is a complex factor. By means of analysis on radiant energy transmission in the atmosphere, the equation of radiant temperature difference transmission is constructed. Thereby, the calculation of the view range of IRIS can be simplified. Based on the deposit volume of vapor and carbon dioxide in the atmosphere under sea level, the atmospheric transmissivity is presented;modification of the height and slant path is considered. We mainly calculate the atmospheric transmissivity of 3～5μm and 8～12μm wave band in horizontal and slant path .Based on NETD and MRTD of IRIS, mathematic models for the view range prediction adapted for point source target and extended source target are studied respectively ,considering target's size and detection probability in calculating the view range of extended source target. Moreover, Catherine-GP thermal camera is evaluated by the models we constructed , calculating the view range of some representative targets . The result shows that the model given in the paper is practicable and feasible. At last, a software is developed on the basis of VB, it can calculate MRTD, atmospheric transimissivity, view range of the point target and extended source target as well.