【作者】 李起成； 杨猛； 陈毅松； 汪国平；

【Author】 Li Qicheng1+, Yang Meng1, Chen Yisong2, Wang Guoping11((HCI & Multimedia Lab of the Department of Computer Science, Peking University,Beijing,100871)2( Department of Computer Science, City University of Hong Kong ,Hong Kong)

【机构】 北京大学计算机科学技术系； 香港城市大学计算机科学系；

【摘要】 本文通过对目前几种基于参照物的相机标定法进行分析,根据其中参照物设计方案为基础提出一种新的设计方案—彩色圆柱。该参照物的设计充分利用了RGB、HSV两种颜色空间的信息,并且通过SUSAN算法可以方便的定位校准点的图像坐标,然后再利用事先测定的空间坐标,就可以根据TSAI方法恢复拍摄每幅照片时相机的内外参数。与其它参照物相比,彩色圆柱参照物具有不存在遮挡、阴影效果小、参照点不共面、拍摄过程简单等优点。通过应用实例表明,该方法简单有效,准确度高。更多还原

【Abstract】 Camera calibration has always been a subject of research in the field of computervision. The key idea behind calibration is to write the projection equations linking the knowncoordinates of a set of 3-D points and their projections, and solve for camera parameters. Inorder to get to know the coordinates of some 3-D points, camera calibration methods rely onone or more images of a calibration pattern: that is, a 3-D object of known geometry, possiblylocated in a known position in space and generating image features which can be locatedaccurately. In image-based modeling system, camera calibration is a key stage, the accuracyof which has a great impact on the consequent result of model recovery. The design of reference model is an important step for camera calibration. A new designscheme, Chromatic Cylinder, is proposed in the paper based on the analysis of several cameracalibration methods currently in use and the principles of reference model design. Whenpictures are being taken, the object to be modeled is put on the top of the reference model. Itis possible to take pictures for the object and reference model from various directions byarbitrarily rotating the reference model, provided that relative positions of the two remain thesame. The scheme makes full use of the information of the color space of RGB and HSV. Theimage coordinate of calibration point can be easily located through SUSAN corner detectionalgorithm. Then with the help of space coordinate measured in advance, the intrinsic andextrinsic parameters of camera can be obtained by TSAI method. Compared with otherreference model, Chromatic Cylinder has the advantage of being occlusion free, low shadeeffect, no co-planar reference point and ease for picture taking. It has been demonstrated byvarious applications that this approach is simple but effective, and enjoys a high rate ofaccuracy.更多还原