基于线阵CCD空间滤波效应的航空相机像移速度测量方法

Image Motion Velocity Measurement Technique Based on Spatial Filtering Effect of Line CCD for Aerial Camera

基于空间滤波测速原理,提出了利用线阵CCD空间滤波效应进行航空相机像移速度测量的新方法。对线阵CCD输出图像进行隔行采样,模拟了多狭缝的空间滤波特性,实现了对航空相机像移速度的光学非接触测量。通过研究空间滤波器的功率谱密度函数,对影响线阵CCD空间滤波特性的关键因素进行了特性分析,并在实验上验证了利用线阵CCD推扫图像模拟多狭缝空间滤波器测量像移速度的可行性。结果表明,对于5～53.2mm/s范围内的像移速度,测量误差导致的像移量误差不大于1/3pixel,能够满足航空相机像移补偿精度的要求。

Based on spatial filtering velocimetry, a new method is proposed by using spatial filtering effect of line CCD for aerial camera. Spatial filtering characteristic of spatial slits is simulated by doing interval sampling with line CCD image, by which an optical non-contact measurement about aerial camera image motion velocity is realized. Besides, with the research of spatial filtering power spectrum density function, key factors affecting the spatial filtering characteristic of line CCD are analyzed. The possibility of measurement about image motion velocity with line CCD push broom image simulating spatial filtering effect is validated with experiments. The results show that the measurement error is less than 1/3 pixel for an image motion velocity between 5 and 53.2 ram/s, which satisfies the requirement of image motion compensating precision for aerial camera.