低温红外镜头星点检测数据处理方法研究

Study on a Method of Data Processing for Star Test of Cryogenic Infrared Lens

在实验室模拟低温真空环境对红外镜头进行星点检测时,不能在像面处直接测得星点光源的像,而是通过在焦面处放置反射镜使系统二次成像的方法测得二次成像的弥散斑大小。二次像斑尺寸的变化将能反映出由温度变化引起的被测镜头焦面处像斑尺寸的变化。通过理论推导得出一次像与二次像弥散斑大小的数学关系,并通过对不同尺寸星点光源、不同像质光学系统的仿真分析,得出星点检测法的检测精度与星点孔直径有关,而与镜头本身成像品质无关。

During the star test to cryogenic infrared lens in the simulated cryogenic - vacuum environment, the image of star source can＇ t be received in focal plane directly. When a mirror was placed in focal plane, the secondary image of star source can be received in object plane. The change of the first image caused by the temperature variation could be obtained from the secondary image. In the paper, the mathematic representation, which expressed the relation between the dispersion spots of the first image and the secondary image, was obtained by theoretical derivation, and then the optical systems with different - sized star sources and that of different imaging qualities were simulated in the optical simulation software. The simulation results indicated that the testing precision was related to the sizes of the star sources, but not the imaging qualities of the lens.