An Automated X-corner Detection Algorithm(AXDA)

According to the central symmetry and bright-dark alteration of the four peripheral regions at the X-corner, an automated X-corner detection algorithm (AXDA) is presented to camera calibration problem. By detecting the gray changes of the image, the algorithm can locate the position of X-corner accurately using the minimum correlation coefficient of the symmetry regions. Cross points of intersection are calculated using the detection points and the least square straight line fitting algorithm. The method can not only realize the sub-pixel X-corner extraction, but also resolve the low automation degree problem of the present detection algorithm under complex background. Experiment results show that the algorithm is an easily-realized, highly-automated and robust method for rotation transform and brightness transform of the X-corner image.