压缩标准的出现，使得图象数据格式普遍为压缩格式，从而促进了压缩域内图象检索技术的迅速发展.为了使人们对基于压缩域的图象检索技术有一概括了解，该文对目前的压缩域检索技术进行了回顾和讨论 :首先，介绍了图象检索系统的基本概念 ;然后，分类分析了不同压缩域的检索技术，包括变换域方法 (如傅立叶变换、离散余弦变换 (DCT)以及子带和小波变换 )和空域方法 (如矢量量化和分形等 ) ;接着，对这些检索方法进行了讨论和比较，并得出一些有用的结论 ;还举例介绍了基于压缩域图象检索技术的实际应用 ;最后对压缩域图象检索技术的研究发展及其应用前景指出了一些可能的方向.

The advent of compression standards, such as JPEG and MPEG, has led to the popularity of the compressed form of image data, and that has brought on the proliferation of image retrieval techniques in the compressed domain. In this paper, we make a comprehensive review and discussions on the compressed domain retrieval techniques proposed in the literature, including the lastest achievements in this field. First, we give the general concepts of the image retrieval technology. Secondly, we analyze different retrieval techniques, including transform domain techniques using Fourier transform, discrete cosine transform, subbands and wavelets, and spatial domain techniques using vector quantization and fractals. Thirdly, we discuss and compare these image retrieval techniques and draw some useful conclusions. In addition, an example application of image retrieval in the compressed domain is presented. Finally, we make a discussion on some open problems and point out possible directions for further research.