传统无损压缩算法对屏幕图像的压缩效果不佳。该文根据典型屏幕图像的特性，以LZ4HC(LZ4 High Compression)算法为具体实现基础，提出一种基于串匹配的高性能低复杂度(String Matching with High Performance and Low Complexity, SMHPLC) 的屏幕图像无损压缩算法。相对于传统字典编码无损压缩算法，新算法提出了以像素为搜索和匹配单位，对未匹配串长度、匹配串长度以及匹配偏移量这3个编码参数进行联合优化编码，并对参数进行映射编码。实验结果表明，SMHPLC具有高性能和低复杂度的综合优势，大幅降低编码复杂度，提高了编码效率。使用移动的文字和图形类的AVS2通用测试序列作为测试对象，对于YUV和RGB两种格式，SMHPLC算法比LZ4HC总体节省码率分别为22.4%，21.2%，同时编码复杂度降低分别为34.6%，46.8%。
Traditional lossless compression algorithms are not efficient for screen content coding. To take the full advantage of special characteristics of screen content, a lossless compression algorithm based on String Matching with High Performance and Low Complexity (SMHPLC) is proposed. It is implemented on the basis of LZ4HC (LZ4 High Compression). The main new ideas are using pixel instead of byte as the basic unit for string searching and matching, adopting joint optimal coding of three parameters of literal length, match length and offset and mapping for three parameters. Experiment results show that SMHPLC has both high coding efficiency and low complexity. Compared to LZ4HC, SMHPLC not only has a coding complexity reduction of 34.6%, 46.8%, but also achieve overall bit-rate saving of 22.4%, 21.2% in YUV, RGB color formats respectively for AVS2 common test sequences in moving text and graphics category.
林涛,蔡文婷,陈先义,周开伦,王淑慧. 一种高性能低复杂度的基于串匹配的屏幕图像无损压缩算法[J]. 电子与信息学报, 2017, 39(2): 351-359.
LIN Tao, CAI Wenting, CHEN Xianyi, ZHOU Kailun, WANG Shuhui. Lossless Compression Algorithm Based on String Matching with High Performance and Low Complexity for Screen Content Coding. JEIT, 2017, 39(2): 351-359.
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