Fast rate allocation schemes for JPEG2000

JPEG2000 can provide excellent rate-distortion performance. However, the conventional post compression rate-distortion (PCRD) optimum algorithm in JPEG2000 is not enough efficient for IC design. Calculation and storage of the rate-distortion slope and search of the optimum truncation points are complexity and they require a large quantity of memory. In this paper, two schemes are proposed to reduce computation and memory for the real-time rate allocation in JPEG2000. A simplification scheme is used to facilitate calculation of the rate-distortion slopes based on some approximate treatments by means of logarithm expression. The other scheme can find all the truncation points for every code-block through a round search based on the 256 quality layers which are divided in parallel with tier1-coding. Compared with PCRD, PSNR of reconstructed images using our schemes decrease very slightly which can be omitted in most applications.