关键词: 图像平滑, 边缘检测, 边缘定位, 精度, 算子

Abstract: Capability of smoothing operator of image directly impacts the precision of edge detection and edge orientation finally.So precision of calibration of CCD camera will be effected.Capability of smoothing operator of image and edge detection operator is compared through experiment.Compared with mean filter，medial filter operator protects details of image edges well under the conditions of good capability protected of wiping off noise.Compared with even filter，medial filter operator can save time and improve efficiency.Compared with Canny operator，Sobel operator not only detects edges of objects exactly but also has the capability of resisting noise strongly.On the side of detecting edge of line，Sobel operator has many advantages and it meets the need of application.

Key words: image smooth, edge detection, edge orientation, precision, operator