Abstract: An automatic corner location algorithm with sub-pixel precision is proposed for chessboard pattern images.The coarse-to-fine layered detection scheme is used.Firstly,with the projection algorithm,the approximate position of chessboard sub-image in target image is located automatically.Secondly,Hough transformation is used in the chessboard sub-image, and the chessboard corner is preliminarily located according to the angle projection image and the amplitude projection image.Lastly,in the coarse corner area acquired in the second step,the final corner with sub-pixel precision is located using the Gaussian interpolation and the Harris algorithm.Furthermore,the lines extracted with Hough transformation is used to automatically arrange the corners.Experiments show that the presented algorithm can automatically locate the chessboard target and the corners with high precision,and can be applied to the calibration of camera with less distortion in wide background environments.