摘要
为了克服传统棋盘格模板标定点检测算法对于遮挡、视角、照明和畸变的局限性,提出一种利用基准点标记代替传统棋盘格黑白方块的改进模板,同时提出模板标定点的相应全自动识别算法。为了提高标定模板的质量,标定模板通过LCD(liquid crystal display)显示。因为LCD具有极高的几何精度和纯平面性,从而提高标定精度。传统摄像机标定同时计算针孔模型和透镜畸变模型,从而2种模型耦合在一起,所得到的标定结果仅对训练数据是有效的,而算法对于新数据的标定误差增加。为了克服2种模型的耦合,提出一种分离地标定2种模型的方法。算法利用模板的射影不变量约束,即交比和直线的射影为直线,求解带有畸变的标定点的校正的坐标,然后线性地求解2种模型。实验结果表明算法稳定且精度高。
In order to overcome the shortcomings that the identification algorithms of traditional checkerboard pattern calibration points are limited by occlusion, viewpoint, illumination and lens distortion, an improved checkerboard pattern template that replaces the black and white squares of traditional checkerboard pattern with fiducial markers is designed, and corresponding fully-automatic identification algorithm of the calibration points is proposed. In order to improve the quality of calibration template, the improved checkerboard pattern is displayed on screen using a LCD （liquid crystal display） display as the calibration template. Because LCD has very high geometric accuracy and pure planarity, so the calibration accuracy is improved. A lot of traditional camera calibration methods compute the pinhole and lens distortion models at the same time, so the two models are coupled; and the computed calibration results are valid only for the training data and their calibration errors increase for new data. In order to overcome the coupling of the two models, a calibration method is proposed, which calibrates the two models separately. The algo- rithm uses the geometric invariant of the calibration template that is the cross-ration invariability, i.e. the projection of a straight line in the space to the camera is a line, to compute the undistorted coordinates of distorted calibration points, and then compute the two models linearly. Experiment results show that the proposed algorithm is stable and has high calibration accuracy.
出处
《仪器仪表学报》
EI
CAS
CSCD
北大核心
2012年第7期1541-1548,共8页
Chinese Journal of Scientific Instrument
基金
黑龙江省自然科学基金(AF200921)资助项目
关键词
摄像机标定
LCD
改进的棋盘格模板
射影不变量
camera calibration
liquid crystal display（LCD）
improved checkerboard pattern
geometric invariant
