Improvement of JPEG2000 Using Curved Wavelet Transform
Demin Wang, Liang Zhang, André Vincent · 2006
The wavelet transform in JPEG2000 is performed using one-dimensional (1D) filtering in the vertical and horizontal directions. This conventional wavelet transform is not effective to represent edges and lines in images. In this paper we present a curved wavelet transform that improves the performance of JPEG200. The curved wavelet transform is performed using 1D filtering along curves that are usually parallel to edges and lines in images. The pixels along these curves can be well represented by a small number of wavelet coefficients. A simple algorithm is proposed in this paper to determine the curves according to image content. Experimental results show that the curved wavelet transform can significantly improve the compression efficiency of JPEG2000, especially for images that contain sharp edges and lines. The coding gain can be up to 1.6 dB in the terms of PSNR.