ADAPTIVE SECONDARY TRANSFORM FOR IMPROVED IMAGE CODING EFFICIENCY IN JPEG2000

This paper proposes a secondary transform for wavelet based image compression, whose aim is to predict detail sub-bands from the corresponding low-pass sub-band so as to improve energy compaction. The proposed prediction strategy exploits the orientation of local image features to untangle aliasing components in the low-pass sub-band, and achieves prediction by projecting the cleaned synthesized low-pass sub-band back into the wavelet domain. At low bit rates, the proposed scheme can considerably reduce distortion in a JPEG 2000 based compression framework, especially for images with strong geometric flow.