光学相关法测量空间相机像移的性能研究

Research on Measurement Method of Image Motion of Space Camera Based on Optical Correlator

为了测量由卫星姿态不稳定或振动等原因引起的空间相机的亚像元像移,使用了光学联合变换相关器(JTC)对安装在相机焦面上的辅助面阵CCD采集到的相邻两帧图像进行相关运算。给出了使用该方法测量像移的原理,搭建了实现JTC的光学实验平台,对JTC测量相机像移的性能进行了实验研究。结果表明,使用JTC完全可以测量空间相机的亚像元像移,并且像移测量精度不随所拍摄景物的内容变化。测量误差服从均值为0的正态分布,在显著性水平为0.05下,像移测量误差的均方差不大于0.12 pixel,完全满足空间相机的使用要求。

To measure the sub-pixel image motion which is caused by satellite attitude instability or vibration,the optical joint transform correlator（JTC） is used,which is based on using the auxiliary plane CCD to record the image motion in the focal plane of the satellite camera.The principle of this method is described,and the experimental platform is built.The measurement performance of the JTC is researched.The results show that the JTC can measure the sub-pixel image motion of the space camera entirely,and the accuracy is not variable with the contents of the input images.The measurement error submits the normal distribution with the mean of zero,and the root mean square（RMS） error is no more than 0.12 pixel under the conspicuous level of 0.05.This can meet the operating requirement of the space camera completely.