Abstract: The basic idea of the algorithm is to extract the color feature of edge area for image retrieval. The edges are divided into inner edge and outer edge and the weight of inner edge (target part) is increased. This is realized through the method of mathematical morphology with multi-scale and multi-structuring elements. By setting a weight for inner and outer edge, the algorithm takes the important of the target into account and overcomes the shortcoming of color histogram which loses the location information．Experimental results show that this method improves the image retrieval performance effectively.

Key words: computer application, image retrieval, mathematical morphology；edge color feature