This document discusses and compares different edge detection techniques used in image processing and computer vision. It begins by introducing image analysis and segmentation, explaining that edge detection is an important tool for identifying objects in images. It then describes several common edge detection algorithms like Sobel, Prewitt, Roberts, and Canny, explaining how each works. The document evaluates the performance of these algorithms on different test images by calculating the root mean square error. It finds that Canny's algorithm produces the best results at locating intensity changes at edges. Finally, it discusses some applications of edge detection and concludes that Canny's is the optimal method for identifying object edges.