Improvement of Performance in JPEG2000 Lossy Compression by Signal Modulation
Zohre Foroushi, Ali Asghar Beheshti Shirazi · 2010
Improvement of performance in sub-band coding system that style in image coding system, is very important. In the coding systems, due to the filter bank that used, coding schemes are classified into two classes, one might have the pair-wise mirror-image property in their filter banks, and performs symmetrically regardless of the sign of the autocorrelation, and the other including JPEG2000 that uses bi-orthogonal 9/7-tap Daubechies filters for lossy compression, has not the mirror image property and performs asymmetrically with inferior performance for negative autocorrelation. In this paper, we want with modulating the negatively-correlated signal sequence by the alternating sign signal with unity magnitude to convert them into positively correlated-sequence. The experimental results for test images show that little gain was obtained by for natural images, since they have small amount of energy in the high frequency bands in horizontal and vertical directions. However 1.5-2dB improvement of PSNR has been obtained for images such as Fingerprint, which have a large amount of energy in high frequency range.