A novel SAR image compression algorithm was presented by using lifting directionlet transform(LDT).The lifting directionlet scheme and improved quad-tree segmentation were proposed to obtain the optimal pair of transform directions,which could capture the image features efficiently.To enhance the coder performance,multi-directional anisotropy hierarchical zerotree was designed,which was suitable to the distribution characteristic of LDT coefficients.Experimental results of real SAR images show that the prop...