基于预测的JPEG2000码率控制算法

Prediction based JPEG2000 rate control algorithm

在低码率下JPEG2000的压缩后率失真最优化算法(PCRD-opt)在运算量和存储量上冗余较大。针对这一问题,该文提出一种基于预测的码率控制算法。该算法通过对目标码率所对应的率失真斜率进行预测,提前截断块编码,避免不必要的编码扫描过程,从而有效降低了运算量和存储量,同时保持图像的质量。在目标码率为0.1 bit/像素时,与PCRD-opt相比,本算法Tier-1层块编码部分的运算时间和存储空间各减少了大约90%,而峰值信噪比(PSNR)基本没有降低。

The conventional post-compression optimization （PCRD-opt） scheme in JPEG2000 does rate-distortion not efficiently use the computational power and working memory when the target bit-rate is low. A prediction based JPEG2000 rate control algorithm is proposed to avoid unnecessary coding pass by predicting the rate-distortion slope with given target bit-rate and stopping block coding in advance. The computations and memory usage is reduced efficiently without sacrificing the image quality therefore. At a bit rate of 0.1 bit per pixel, the computational complexity and working memory of Tier-1 coding is reduced by up to 90% compared with PCRD-opt, with no reduction in the peak signal-to-noise （PSNR）.