Visually lossless compression of synthetic aperture radar images

A task of visually lossless but, in fact, lossy compression of synthetic aperture radar (SAR) images corrupted by intensive speckle is considered. A method based on discrete cosine transform (DCT) applied in 8×8 blocks is proposed. The method is adapted to spatial DCT spectrum of speckle and its multiplicative nature. It is shown that the proposed method allows providing compression ratio (CR) of about 3.2...3.5 for simulated and real life SAR images which is sufficiently larger than for image lossless compression techniques.