Simulating the infrared image of targets by an equivalent radiation-concentrating method

An equivalent radiation-concentrating method was developed for calculating the radiative flux of targets into sensor pixels array in an infrared (IR) detecting system. This method contains division of the imaging process: the formation and transfer of the radiation field of targets and the concentration of it in the IR optical system. In the first process, the Monte Carlo (MC) method is adopted for simulating the formation of the equivalent radiation and for simulating the transfer of it to the IR system. Then in the later process, the optical relations are employed for locating the image and for calculating the light intensity transformation. The developed method was applied for calculating the infrared image of the SDM airplane at different detecting azimuth, and the results were compared in terms of efficiency with those from the reverse Monte Carlo method that traced rays from the sensor pixels array. It is shown that for one single detecting azimuth, the developed method is closed to the reverse Monte Carlo method with respect to efficiency; for multiple detecting azimuths, compared to the reverse Monte Carlo method that coupled the generation and concentration of the effective radiation of targets, the developed method results in computing cost savings and so is more suitable in engineering applications.