基于数字微镜器件(DMD)的红外景象模拟器在室内环境下通过模拟真实景物及其环境的红外辐射来测试红外成像系统的性能。为实现基于DMD的红外景象模拟器能够满足不同待测系统的视场角匹配, 同时为避免投影系统与照明系统发生空间上的重叠, 设计了一套配有分光棱镜的红外变焦投影系统。该系统工作波段为8～12 μm, F数为2.7, 采用光学补偿变焦方式,可实现50/100/150/200 mm四档变焦。根据四组元系统负组补偿原理及其高斯光学公式对系统光学参数进行计算, 选用与参数相近的初始结构进行处理及优化。设计结果表明, 各焦距位置在20 lp/mm处的调制传递函数值均接近衍射极限, 符合使用要求。

The infrared scene simulator based on digital micro-mirror device(DMD) can test the performance of infrared imaging system by simulating the infrared radiation of the real object and environment in the indoor environment. A set of the infrared zoom projection system with dispersion prism was designed by ZEMAX optical software. The system can match the different viewing angle of the system and avoid overlapping between projection systems and illumination systems on the space. The system can work for the band of 8-12 μm. The F number of the system is 2.7. A zoom optical compensation way was used in the system. And the system can realize the focal lengths of 50/100/150/200 mm through four zoom blocks. According to the principles and Gaussian optics formula of four-component system sub-group compensation, the optical parameters of the system were counted; the initial structure which was similar to the optical parameters was adopted and then optimized. The design results show that the image position is stable and the modulation transfer function(MTF) curve at 20 lp/mm of each focal length is closed to the diffraction limit during zoom process, which could conform to the requirements.