Moving-Target Detection in SAR Images Using Difference Between Two Looks

Moving targets can be detected in synthetic aperture radar (SAR) images using the difference between two looks because in the two looks, the images of a stationary target are similar, but the images of a moving target are different. In this article, an elaborate scheme is presented to bring this idea into effect. First, the complex image is compensated to eliminate the shifting and the blurring of the stationary ground due to the velocity error of the radar, and this will decrease the loss of the similarity between the two looks of the stationary ground. Then, the Doppler spectrum is halved, each half is used to generate a look, and the two looks are despeckled to reduce the loss of their similarity. Finally, the difference between the two looks is characterized, smoothed, and thresholded to indicate moving targets. This scheme is effective for targets moving in range, azimuth, or both. It is also easy to implement and efficient in computation.