EDGE detection technique has been used in variety of image processing applications include extracting the edges from image and typically is utilized before object segmentation and feature extraction [1].
Edges are recognized by abrupt intensity variations in an image. The first gradient is typically calculated to locate the edges. The 3 x 3 masks are used to extract the edges from image, and convolved them through it. Prewitt, Canny and Sobel algorithms have been commonly used for edge detection purposes with different masks.
Perwitt edge detection technique is selected due to efficiency and simplicity in the single mask. Figure 1 shows typical Perwitt edge detection masks. In this technique, the edges are detected by convolving horizontal and vertical masks Gx and Gy respectively, through the image. The masks are orthogonal to each other and use to measure the difference among the adjacent pixels gray level in horizontal and vertical direction.