Research On Infrared Scene Simulation And The Development Of Simulation System

Infrared imaging system has been widely exploited in the military field, which determines it is necessary to conduct performance evaluation because of the complicated application situation. Infrared scene simulation can generate images acquired in different weather condition with different infrared cameras, which can be used for comprehensive performance evaluation. As the application broadens, an increasing requirement for images with more thermal detail, more accurate in terms of radiation and higher computational efficiency continues to be highly valued.Facing the new requirement, theoretical and technical research on infrared scene simulation was conducted and a simulation platform was developed. According to infrared imaging principle, the components constituting an infrared simulation system was analyzed, including virtual scene construction, radiometric calculation, radiometric propagation through atmosphere, infrared sensor effects and a summary on necessary data for simulation. An OptiX based parallel temperature calculation program for natural scene was also developed to satisfy the new requirements for thermal definition, thermal shadow and computational efficiency. It harnesses the powerful parallel computation function of GPU, which is capable of improving computational efficiency compared to serial computation using CPU. Furthermore, its ray tracing function facilitates the sun shadow judgment, using which the thermal shadow effect can be manifested. In addition, a material texture mapping method and an inverse temperature texture mapping method were exploited to increase thermal definition. In terms of radiometric calculation, a parallel multiple path tracing method was proposed to fully sample the hemispheric space, which can thus improve the radiometric accuracy. In order to accelerate the integral convergent rate, Monte Carlo integration and importance sampling method were applied. To satisfy the real-time simulation requirement, an infrared simulation platform based on OSG was also developed and the programmable shading language GLSL was exploited for radiometric algorithm development.The simulation results indicate the parallel temperature calculation method has a good performance in improving thermal definition and presenting thermal detail. And qualitative analysis demonstrates the temperature evolvement in one day is in accordance with the actual situation. As for the multiple path tracing method, if an accurate probability density function is available for importance sampling, the error between theoretical result and the proposed method is low. The OSG based infrared simulation platform has good real-time performance and can be used for large-scale scene simulation. In summary, the research has made a beneficial supplement to the current deficiency, which will definitely propel the study on infrared scene simulation forward.