X-corner points are widely used in camera calibration and visible-spectrum visual tracking system as they can provide not only location information, but also direction information. To accurately detect the location and direction of X-corner points, a new algorithm based on the symmetry calculation of X-corner points was proposed. The algorithm mainly consists of two parts. First, the pixel position of the X-corner is determined by using the value of symmetry calculation. Then the sub-pixel location for the X-corner was obtained based on the quadratic curve fitting and inter-section of lines. Through a series of experiments and a comparison with Harris algorithm and Micron Tracker system, the impacts of Gauss noise and distortion on the positioning accuracy and robustness were analyzed. Experiments show that the method can effectively detect X-corners and exclude other types of corner points and disturbance, and thus has higher localization accuracy and robustness.
孟偲, 薛姣. 具有方向特性的X角点的亚像素检测定位[J]. 北京航空航天大学学报, 2015, 41(4): 580-588.
MENG Cai, XUE Jiao. Sub-pixel X-corner detection and location with directional characteristics. JOURNAL OF BEIJING UNIVERSITY OF AERONAUTICS AND A, 2015, 41(4): 580-588.
Sánchez-Margallo J A, Sánchez-Margallo F M,Pagador J B,et al.Technical evaluation of a third generation optical pose tracker for motion analysis and image-guided surgery[M]//Clinical Image-Based Procedures.From Planning to Intervention.Heidelberg:Springer,2013:75-82.
[2]
王志衡,吴福朝, 王旭光.基于局部方向分布的角点检测及亚像素定位[J].软件学报,2008,19(11):2932-2942. Wang Z H,Wu F C,Wang X G.Corner detection and sub-pixel localization based on local orientation distribution[J].Journal of Software,2008,19(11):2932-2942(in Chinese).
[3]
Zhang Z Y. A flexible new technique for camera calibration[J].IEEE Transactions on Pattern Analysis and Machine Intelligence,2000,22(11):1330-1334.
[4]
刘阳成,朱枫. 一种新的棋盘格图像角点检测算法[J].中国图象图形学报,2006,11(5):656-660. Liu Y C,Zhu F.A new algorithm for X-corner detection[J].Journal of Image and Graphics,2006,11(5):656-660(in Chinese)
[5]
Bouguet J Y. Camera calibration toolbox for matlab[EB/OL].California,Tex:California Institute of Technology,2009 (2013-12-02).http://www.vision.caltech.edu/bouguetj/calib_doc/.
[6]
Bradski G, Kaehler A.Learning OpenCV:computer vision with the OpenCV library[M].Sebastopol:O'Reilly Media,Inc.,2008:422-430.
Harris C, Stephens M.A combined corner and edge detector[C]//Proceedings of Alvey Vision Conference.Manchester:Organising Committee AVC 88,1988,15:147-152.
[9]
王崴,唐一平, 任娟莉,等.一种改进的Harris角点提取算法[J].光学精密工程,2008,16(10):1995-2001. Wang W,Tang Y P,Ren J L,et al.An improved algorithm for Harris corner detection[J].Optics and Precision Engineering,2008,16(10):1995-2001(in Chinese).
郝颖明,朱枫. 摄像机在线标定中的棋盘格角点自动检测方法[J].计算机工程,2007,33(17):213-215. Hao Y M,Zhu F.Automatic X-corners detection for online camera calibration[J].Computer Engineering,2007,33(17):213-215(in Chinese).
[12]
储珺,郭卢安政, 赵贵花.采用环形模板的棋盘格角点检测[J].光学精密工程,2013,21(1):189-196. Chu J,Guo L A Z,Zhao G H.Chessboard corner detection based on circular template[J].Optics and Precision Engineering,2013,21(1):189-196(in Chinese).
[13]
胡海峰,侯晓微. 一种自动检测棋盘角点的新算法[J].计算机工程,2004,30(14):19-21. Hu H F,Hou X W.A new algorithm for automatically detecting chessboard corners[J].Computer Engineering,2004,30(14):19-21(in Chinese).
[14]
Chen D, Zhang G J.A new sub-pixel detector for X-corners in camera calibration targets[J].WSCG (Short Papers),2005,5:97-100.
[15]
张广军. 视觉测量[M].北京:科学出版社,2008:57-61. Zhang G J.Vision measurement[M].Beijing:Science Press,2008:57-61(in Chinese).
[16]
魏军,刘达, 王田苗,等.基于段测试的X角点检测与亚像素定位[J].机器人,2011,33(1):97-101. Wei J,Liu D,Wang T M,et al.Segment test based X comer detection and sub-pixel localization[J].Robot,2011,33(1):97-101(in Chinese).
[17]
Rosten E, Porter R,Drummond T.Faster and better:a machine learning approach to corner detection[J].IEEE Transactions on Pattern Analysis and Machine Intelligence,2010,32(1):105- 119.
[18]
Lowe D G. Distinctive image features from scale-invariant key points[J].International Journal of Computer Vision,2004,60(2): 91-110.
[19]
Bay H, Tuytelaars T,Van Gool L.Surf:speeded up robust features[C]//Proceedings of the European Conference on Computer Vision.Heidelberg:Springer,2006:404-417.
[20]
尚雅层,陈静, 田军委.高斯拟合亚像素边缘检测算法[J].计算机应用,2011,31(1):179-181. Shan Y C,Chen J,Tian J W.Sub-pixel edge detection algorithm based on Gauss[J].Journal of Computer Applications,2011,31(1): 179-181(in Chinese).
[21]
郭永芳,于明, 孙以材.一种改进的快速角点检测方法研究[J].计算机工程与应用,2011,47(12):159-161. Guo Y F,Yu M,Sun Y C.Study on advanced rapid corner detection method[J].Computer Engineering and Application,2011,47(12):159-161(in Chinese).