DCT域网格编码量化及其在图像量化中的应用  

TCQ in DCT Domain and its Application in Image Quantization

作　　者：周正华[1] 郑勇[1] 朱维乐[1] 

机构地区：[1]电子科技大学电子技术系

出　　处：《信号处理》2001年第1期27-30,共4页Journal of Signal Processing

摘　　要：本文提出了在离散余弦变换（ ＤＣＴ）域内作网格编码量化（ ＴＣＱ）的新方法。该方法不仅利用了信号间的时间相关性，而且也利用了信号变换域内的相关性，该方法首先用一维或二维ＤＣＴ变换减小变换域内的相关性，然后利用卷集编码和信号空间扩展来增大量化信号间的欧氏距离，并用维持比算法寻找最优量化序列。仿真结果表明，基于二维ＤＣＴ的ＴＣＱ方法在相对大的灰度率下，比传统的ＴＣＱ方法好２ｄＢ左右，与此同时，ＴＣＯ又比最优标量量化好２ｄＢ左右。该方法还具有编码计算复杂度适中，解码简单以及对误差扩散不敏感的优点。A new method which performs Trellis coded quantization (TCQ) in DCT domain is Proposed This method utilizes not only time correlation, but also the correlation in DCT domain. First, one or two dimensions DCT are performed to reduce the correlation in DCT domain, then convolutional coding and signal space expanding are used for increasing Euclidian distance between signals. Finally, Viterbi algorithm is used to find a optimized survived quantized sequence. Simulation states TCQ encoder based on two dimension DCT has a advantages 2dB or so. over conventional TCQ. At the same time, TCQ has a advantages 2dB or so over optimized scalar quantization. The method also has such capability that it has only modest encoding complexity with simple decoding and its insensitive to channel errors.

关 键 词：网格编码量化 离散余弦变换 图像量化 信源编码 图像编码 

分 类 号：TN911.21[电子电信—通信与信息系统] TN919.81[电子电信—信息与通信工程]