Abstract:A new algorithm was proposed based on the geometric symmetry to detect grid corners. The method can be utilized in camera calibration where chessboard-like patterns were often used. Based on the observation of the geometric symmetry of such patterns, the new algorithm could be regarded as a coarse-to-fine process. Coarse detection defined the corner candidates and then precise extraction was used based on symmetry analysis. Experimental results show that the algorithm assures an efficient and accurate detection and the procedure can be carried out automatically.