采用环形模板的棋盘格角点检测

Abstract

Over exposure and camera lens distortion often result in the separation and local area asymmetry of a chessboard corner and the existing chessboard corner detection algorithms can not extract the corner information in such conditions accurately.Therefore,this paper proposed a detecting algorithm based on the circular template under an image coordinate.The symmetry and interchangeability needed by gray distribution of the local area for the chessboard corner were analyzed,and the properties of a convoluted image for the circular template were obtained.On the basis of the properties,the chessboard corner was defined and extracted.Finally,the symmetry of local redundant corner distribution was used to remove the redundant corner to improve the corner detection accuracy and to allowed the extracted accuracy of the corner to sub-pixel level in merely one step by employing the image coordinate.Experiment results show that our algorithm can achieve better results in over exposure and lens distortion both at simple backgrounds and complex scenes,and it is characterized by higher operation speed and smaller errors.Applying proposed algorithm to a camera calibration,a re-projection error less than 0.3 pixels is obtained.