SAR image compression using wavelet transform and soft-thresholding

Synthetic aperture radar (SAR) image compression is important in image transmission and archiving. Our studies show that the speckle noise which is inherent in SAR imaging systems is also an obstacle to image compression. In order to improve the reconstructed image quality and increase the compression efficiency, the wavelet domain soft-thresholding technique is implemented to reduce the speckle noise before compression is performed. The embedded zerotree coding algorithm is adopted to compress the de-speckled images. An 8:1 compression ratio with PSNR greater than 40 dB can be achieved for typical airborne SAR images with no significant distortion introduced by image compression.