A SAR image compression algorithm based on Mallat tower-type wavelet decomposition

Image compression algorithms based on wavelet transform can achieve ideal effect on optical image, while cannot do well in SAR image compression. The paper introduces wavelet encoding in optical image compression into SAR image processing and designs an improved SAR compression algorithm based on Mallat tower-type wavelet decomposition according to characteristics of SAR image. The algorithm firstly conducts noise reduction in wavelet domain on image and then performs differential pulse lossless coding on low-frequency sub-band after removing speckle noise. The high-frequency is scanned for important coefficients using spatial direction tree similar to SPIHT algorithm and processed with universal trellis coded quantization. The Euclidean distance among important coefficient can be expanded to improving quantification gain. It can be seen from simulation results analysis on algorithm compression performance that the proposed improved algorithm is more suitable for SAR image compression compared with SPIHT algorithm and JPEG2000 standard.