Novel scheme for JPEG2000 rate control based on number of coding passes

A novel scheme for JPEG2000 rate control was proposed based on the weight of wavelet quantification and the number of coding passes. The bytes of the compressed code steam were pre-assigned before coding the bit plane in terms of the sub-band and the number of coding passes contained in current code block. In the coding process, if the coded bytes greater than/equal to the bytes pre-assigned the code stream was truncated, i.e. truncating it in real time. Compared with the standard post-coding rate distortion (PCRD) algorithm, the proposed algorithm has no spending in calculating rate-distortion slope and searching for optimum truncation points. Code stream truncation could be fulfilled adaptively in code-block coding. Experiments show that for Lena image under 0.5 bit per pixel compression, the memory capacity needed and encoding time are only 6.8% and 18.7% of PCRD respectively, and the difference of the image quality between them is less than 0.8 dB. The scheme consumes less resource and greatly increases the encoding speed, so it is also better fitted to VLSI implementation.