A spatial moment operator of image edge model for the three-gray-level image is proposed.Firstly the Laplacian of Gaussian(LOG) operator is used to locate the edge at the level of pixel quickly,and then the spatial moment is used for subpixel location of the edge in the domain containing edge points.The beeline and ellipse edge pixel points are extracted by the Hough transform.The least square fitting edge extraction is adopted to obtain the subpixel beeline and ellipse.The validity and precisio...