Image motion measurement for airborne camera based on joint transform correlation

To improve the precision of image motion measurement for airborne pendulum-swing cameras, a method of image motion measurement combining the coordinate transformation and image correlation is proposed. First, the initial image motion velocity is calculated by using the coordinate transformation method. Then, the image motion velocity residual errors are compensated by using image joint transformation correlation method. The joint images are produced by an area array CCD which is set paralleled to the imaging linear TDI CCD in the focal plane of the camera. The current and the reference frames output from the area array CCD are combined into a joint image. By taking 2D spatial correlation computation on the joint image, the image motion correction vector is obtained. Corrections of the forward and pendulum-swing image motions are determined by decomposing the vector. Simulation test results show that the image motion measurement error is less than 0.1 pixels for input images with SNR=4 dB.