一种快速的DEM数据无损压缩算法  

Fast Algorithm for DEM Lossless Compression

作　　者：郑晶晶[1,2] 方金云[1] 韩承德[1] 

机构地区：[1]中国科学院计算技术研究所,北京100190 [2]中国科学院研究生院,北京100049

出　　处：《系统仿真学报》2010年第10期2397-2403,共7页Journal of System Simulation

基　　金：国家"973"计划基金资助项目(2004CB318202)

摘　　要：为减少网络GIS海量数字高程模型(Digital Elevation Model,DEM)数据的存储与传输数据量,提出一种编解码快速、压缩位流具有三种嵌入(分辨率嵌入、感兴趣区域嵌入和质量嵌入)特点的DEM无损压缩算法——DFC(DEM Fast Compression)算法。选用2/6可逆整数小波分解DEM数据,对变换系数的每级分辨率数据按照区域划分分区,对每个分区子带系数的每一个位面在一次扫描中完成简单高效的自适应游程Golomb_Rice编码。实验数据表明:比JPEG2000算法编码、解码时间分别减少了61.12%和56.23%,而压缩比仅仅降低了10.91%;比SPIHT算法编码、解码时间分别减少了58.83%和50.71%,而压缩比仅仅降低了7.54%;比GZIP压缩比平均提高了74.05%;比n点最优预测算法压缩比提高了5.83%。DFC算法在保持较好的压缩性能的同时,大幅度减少了编解码时间,并且在各级分辨率具有很好的精度性能。To decrease DEM data volume for storage and transmission in net-GIS,the DFC （DEM Fast Compression） algorithm for DEM lossless compression was proposed,which has three embedded characters （resolution,region of interest,and fidelity）.The 2/6 reversible integer wavelet was selected to decompose DEM data.Every resolution of the transform coefficients was partitioned into many precincts according to the area.In each sub-band of each precinct,only in one pass,the bits of every bit-plane were run-length encoded with adaptive Golomb_Rice coding which is very simple and effective.The experiments show that：compared with JPEG2000,DFC＇s encoding and decoding time decrease 61.12% and 56.23% respectively,while the compression ratio decreases only 10.91%;compared with SPIHT,DFC＇s encoding and decoding time decrease 58.83% and 50.71% respectively,while the compression ratio decreases only 7.54%;compared with GZIP,DFC＇s compression ratio increases 74.05%;compared with n neighbors＇ prediction algorithm,DFC＇s compression ratio increases 5.83%.Thus,the DFC algorithm decreases the coding and decoding time largely while maintains favorable compression performance,and has excellent accuracy performance in every resolution data.

关 键 词：数字高程模型 无损压缩 地理信息系统 Golomb编码 小波编码 

分 类 号：TP391.9[自动化与计算机技术—计算机应用技术]