Study on texture feature extraction in region-based image retrieval system

Texture is an important feature to describe images. Though lots of work has been done for efficient texture feature extraction from rectangular images, no much effort has been made in texture feature extraction from arbitrary-shaped regions in region-based image retrieval (RBIR) system. In this paper, we present an efficient texture feature extraction algorithm for arbitrary-shaped regions. This algorithm first extends an arbitrary-shaped region into a rectangular area onto which block transformation can be applied. Based on the projection-onto-convex-sets (POCS) theory, a set of coefficients best describing the original region are finally obtained, from which texture feature of the region can be extracted. Via intensive experiments, we select a set of parameters proper for image retrieval purpose. Experimental results on real-world image database demonstrate the effectiveness of the proposed algorithm for image retrieval purpose