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计算机工程 ›› 2012, Vol. 38 ›› Issue (04): 202-204. doi: 10.3969/j.issn.1000-3428.2012.04.066

• 工程应用技术与实现 • 上一篇    下一篇

一种无链表零树熵编码算法及其FPGA实现

梁春锋 a,唐艳发 b,孙红亮 b,张 利 a   

  1. (清华大学 a. 电子工程系;b. 微电子所,北京 100084)
  • 收稿日期:2011-07-19 出版日期:2012-02-20 发布日期:2012-02-20
  • 作者简介:梁春锋(1984-),男,硕士研究生,主研方向:图像压缩,集成电路设计;唐艳发、孙红亮,硕士研究生;张 利,教授、博士生导师
  • 基金资助:
    国家自然科学基金资助项目(60972022)

Listless Zerotree Entropy Coding Algorithm and Its FPGA Implementation

LIANG Chun-feng a, TANG Yan-fa b, SUN Hong-liang b, ZHANG Li a   

  1. (a. Department of Electronic Engineering; b. Institute of Microelectronics, Tsinghua University, Beijing 100084, China)
  • Received:2011-07-19 Online:2012-02-20 Published:2012-02-20

摘要: 传统熵编码算法复杂度高,且硬件实现较难。为此,提出一种易于FPGA硬件实现的无链表零树图像编码改进算法,该算法结合LZC和SPIHT算法的特点,增加了对孙子节点的判断,克服SPIHT算法中内存消耗大、复杂度高以及LZC算法中图像重建质量下降等缺点。采用该算法的编码器在对任意尺寸图像进行5层小波变换时,所需缓存固定为1 536 bit,远小于SPIHT算法。在相同比特率的情况下,图像重建质量PSRN值比LZC算法平均提高约0.7 dB。在Xilinx Virtex4 LX100硬件平台上进行实验,结果表明,当时钟频率为100 MHz、压缩率为1/40时,该算法处理1 600×1 200×24 bit图像的速度可达20 f/s。

关键词: 熵编码, 零树, FPGA实现, 图像压缩, 小波变换

Abstract: Since the traditional entropy coding algorithm is hard to realize using hardware method and with high complexity, a Listless Zerotree image Coding(LZC) algorithm is proposed and implemented in Field Programmable Gate Array(FPGA) platform. The algorithm adopts the features from LZC and Set Partitioning in Hierarchical Trees(SPIHT), and adds the judgment for grandchildren nodes. With the improvement, the algorithm overcomes the high memory overhead and high complexity of SPIHT, and enhances the coding quality of LZC. For any size of images, the memory overhead for this coder implemented in FPGA is fixed, 1 536 bit, far less than that of SPIHT. The PSNR of decoded image is enhanced about 0.7 dB than LZC under the same compression bitrate. When the algorithm is implemented in Xilinx Virtex4 LX100, running at 100 MHz, it performs a frame rate of 20 f/s for 1 600×1 200×24 bit images with a compression ratio of 1/40.

Key words: entropy coding, zerotree, Field Programmable Gata Array(FPGA) implementation, image compression, wavelet transform

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