本文通过对扫描镜鼓和棱镜在扫描过程中运动轨迹的分析,推导出不同扫描角所引起的散焦量变化和它对红外成象系统性能影响的数学表达式。 In this paper, through analyzing the movement trajectory of scanning mirror drum and prism during the scanning process, the mathematical expression of the defocusing quantity change caused by different scanning angles and its influence on the performance of infrared imaging system is deduced.