Content-based image retrieval (CBIR) work includes feature selection, object representation, and matching. If a shape is used as feature, edge detection might be the first step to extract that feature. Invariance to translation, rotation, and scale is required by a good shape representation. Sustaining deformation contour matching is an important issue at the matching process.

In this paper, an efficient and robust shape-based image retrieval system is proposed. We use the Prompt edge detection method [18] to detect edge points, which is compared with the Sobel edge detection method. We also introduce a shape representation method, the mountain-climbing sequence (MCS), that is invariant to translation, rotation, and scale problems. The results of our proposed method show a superior matching ratio even in the presence of a modest level of deformation.