Abstract: Content based image retrieval (CBIR), a technique which uses visual contents to search images from the large scale image databases, is an active area of research for the past decade. It is increasingly evident that an image retrieval system has to be domain specific. In this paper, various edge detection method are discussed.Edges are detected in areas of the image where the intensity level fluctuates sharply, the more rapid the intensity change the stronger the edge[1]. A good edge detection stage makes the formation of extended boundaries and object recognition easier; errors due to a poor edge detector soon become magnified as more processing is performed, so care must be taken in choosing the right edge detector (or operator) for the job.In this paper, an efficient and robust shape-based image retrieval system is proposed. We use the Prompt edge detection method to detect edge points, which is compared with the Sobel edge detection method.

Keywords: Canny, Laplacian, Prewitt, Robert, Sobel.