CCSDS图像压缩算法中位平面编码的VLSI设计

发布时间：2018-02-07 17:00

本文关键词： 图像压缩 CCSDS FPGA 位平面编码并行扫描　出处：《中国科学院大学(中国科学院国家空间科学中心)》2017年硕士论文　论文类型：学位论文

【摘要】：近年来随着传感器技术的快速发展,人们获取的星载遥感图像的数据量正以几何级数增长,但由于星载系统资源和数据下行传输带宽有限,所以图像压缩成了必不可缺的环节。2005年空间数据系统资源委员会(CCSDS)发布了新一代星载图像压缩推荐标准CCSDS 122.0-B-1,该标准采用了小波变换技术和位平面编码方案,支持图像压缩从无损到有损连续可调,并且在兼顾压缩效率的前提下具有较低的设计复杂度,适用于星载平台,具有良好的应用前景。论文在深入研究CCSDS标准图像压缩算法的基础上,采用Verilog HDL语言设计了图像编码系统。在算法的VLSI实现中位平面编码模块是资源消耗的关键所在,本文实现了一种新的位平面扫描方案,将原串行扫描方式改进成为并行扫描,扫描时间消耗大大降低,提高了压缩编码效率。论文设计了CCSDS算法的VLSI实现架构并做了仿真验证,主要工作如下:(1)深入研究了CCSDS 122.0-B-1标准,分析了图像压缩算法的流程,对其中小波DC系数编码、小波AC系数编码部分进行了详细论述。(2)在CCSDS原算法的基础上进行了优化设计,使用并行扫描结构实现位平面扫描编码。(3)使用Verilog HDL语言设计了图像压缩系统的接口模块和编码模块,包括图像预处理模块、DC系数编码模块、AC系数位深编码、AC系数编码等模块的VLSI设计。(4)使用Modelsim对图像编码系统进行功能仿真,验证系统设计的合理性。
[Abstract]:In recent years, with the rapid development of sensor technology, the data volume of space-borne remote sensing images is increasing in geometric series, but the bandwidth of space-borne system resources and data downlink transmission is limited. In 2005, the Committee of Spatial data system Resources (CCSD) issued a new recommendation standard CCSDS 122.0-B-1, which adopts wavelet transform technology and bit-plane coding scheme. It supports image compression from lossless to lossy continuous tunable, and has low design complexity on the premise of taking into account compression efficiency, so it is suitable for spaceborne platform. It has a good application prospect. Based on the in-depth study of the CCSDS standard image compression algorithm, this paper designs an image coding system using Verilog HDL language. The implementation of the median plane coding module in the VLSI of the algorithm is the key to the resource consumption. In this paper, a new bit-plane scanning scheme is implemented, in which the original serial scanning method is improved to parallel scanning mode, the scanning time consumption is greatly reduced, and the compression coding efficiency is improved. The VLSI implementation architecture of CCSDS algorithm is designed and simulated. The main work is as follows: (1) the CCSDS 122.0-B-1 standard is deeply studied, the flow of image compression algorithm is analyzed, and the wavelet DC coefficient coding and wavelet AC coefficient coding part are discussed in detail.) based on the original CCSDS algorithm, the optimization design is carried out. The interface module and coding module of image compression system are designed by using Verilog HDL language. The VLSI design of the AC coefficient bit depth coding and AC coefficient coding module including the image preprocessing module / DC coefficient coding module. (4) the functional simulation of the image coding system using Modelsim is carried out to verify the reasonableness of the system design.
【学位授予单位】：中国科学院大学(中国科学院国家空间科学中心)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP751

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