针对旋转双棱镜扫描成像中棱镜引起的成像畸变进行研究并通过逆向光线追迹对其实施校正.为估算畸变的特点和程度,根据视轴指向及视场尺寸确定棱镜转角和入射光方向,基于矢量形式的折射定律对视场跨度内的光线通过两棱镜实行追迹.以锗棱镜的红外成像及玻璃棱镜的可见光成像为例模拟成像变形.结果表明,图像沿着偏离系统轴的方向被压缩.偏转角越大,图像变形越突出.为校正成像畸变,从像点通过棱镜实行逆向光线追迹.针对可见光成像搭建旋转双棱镜扫描成像系统并分析其成像畸变,结果表明成像畸变的模拟预测与实验观测结果相符.无论针对模拟图像还是实际图像,逆向光线追迹都能有效地校正成像畸变,改善成像质量.该畸变分析及其校正方法对旋转双棱镜成像应用具有一定的参考价值.

The image distortions caused by the prisms are investigated in rotational double prism scanning imaging and the inverse ray tracing is performed to correct the image distortions.To evaluate the characteristic and the extent of distortions,the rotation angles of prisms and the incident direction are obtained based on the direction of the line of sight and the size of the field of view.The rays from the field of view span are traced through the two prisms based on the vector form Snell’s law.The image deformations are modeled as case examples for the infrared images of germanium prism system and the visible images of glass prism system.The result shows that the images are compressed along the deflection direction from the system axis and the deformations become more prominent with increase in deviation angle.To correct the distorted images,the rays from the image points are traced inversely through the prisms.A scanning imaging system for the visible band,based on the rotational double prism,is built and its image distortions are analyzed.The results show that the simulation predictions for image distortions are correspond with the experimental observations.The inverse ray tracing can effectively correct the distortion and fairly improve the quality of the distorted images for both simulation images and experimental images.The analysis results about distortion and its correction method have referenced value on the imaging applications of rotational double prism.