A JPEG2000 re-encoding scheme with high quality performance for JPEG coded pictures

This paper describes a fine quality re-encoding scheme that converts JPEG to JPEG2000. The problem is that the quality of a re-encoded picture deteriorates by 0.5-1.0 dB when a JPEG picture is re-encoded quite simply by JPEG2000 at the same coding rate, although JPEG2000 has essentially higher compression ability and achieves better quality by 1-2 dB than JPEG. At first, the causes are analyzed in detail. Next, this paper proposes a new re-encoding scheme for quality improvement. A new algorithm prevents re-encoded picture from degrading its quality by modifying the factitious wavelet coefficients affected because of block artifacts. Finally, the simulation results show that the proposed scheme improves the quality of a re-encoded picture by about 0.15 dB. As a result, proposed scheme is used for re-encoding in future.