As very large collections of images are becoming common , there is a growing interest in image database that can be quired based on image content . content - based image retrieval ( cbir ) has become an important research issue aiming at providing effective means for image retrieval on large image databases 随着图象数据的大量涌现,基于内容的图象检索技术已成为研究热点,其目的是为了对大容量图象库提供有效的检索手段。