航空摆扫相机转弯成像像移分析及补偿

为保证航空摆扫相机转弯成像过程中的成像质量,对其像移计算及补偿方法进行了研究。根据航空摆扫相机的成像原理,利用几何建模及速度矢量分解建立了转弯成像像移计算模型,给出了基于均值补偿的转弯前向像移补偿方法。转弯前向像移补偿分析表明:相机焦距为500 mm,曝光时间为0.01 s,速高比为0.02 rad/s,纵向视场角为10°,转弯角速度为0.5(°)/s时,最大前向像移补偿残差量为2.22μm;转弯角速度为1.5(°)/s时,最大前向像移补偿残差量为3.36μm。另外,转弯横向像移补偿分析表明:横向像移量随纵向视场角幅值的增加而增大,曝光时间为0.005 s,横向视场角为30(°),转弯角速度为1(°)/s时,横向像移量在纵向视场角为4.5°时达到3μm。转弯成像试飞实验结果表明:得到的图像像质优良,无几何形变,前向像移补偿良好,验证了本文提出的转弯成像像移补偿方法的正确性。

Image motion analysis and compensation for aerial scanning camera during turning flight

The image motion calculation and compensation for an aerial scanning camera in turning imaging was researched to improve its imaging quality. The geometrical modeling and velocity vector decomposition were utilized to establish the image motion computation model of turning imaging according to the imaging principle of the aerial scanning camera. The mean compensation method for forward turning imaging motion was proposed based on the established model. The forward image motion compensation analysis on the turning imaging indicates that the maximum residual of forward image motion compensation is 2.22μm at the focal length of camera in 500 mm, exposure time in 0.01 s, speed height ratio in 0.02 rad/s, the longitudinal field of view in 10°, and the angular velocity in 1(°)/s and that is 3.36μm at the angular velocity in 1.5(°)/s. Moreover, the latitudinal image motion compensation analysis on the turning imaging indicates that the latitudinal image motion value increases as the magnitude of longitudinal field of view increased, and the value reaches 3μm while the exposure time is 0.005 s, the latitudinal field of view is 30°, the angular velocity is 1(°)/s and the longitudinal field of view is 4.5°. The imaging experiment of test turning flight obtains excellent image quality without geometric distortion and proper forward image motion compensation, which verifies the validity of the proposed image motion compensation method for turning imaging.