基于局部单应性矩阵的结构光系统标定研究

Research on Calibration of Structured Light System Based on Local Homography Matrix

在基于结构光测量系统中,投影仪标定对物体的三维测量精度有着直接的影响。通过投影仪投射多幅正交格雷码至棋盘格标定板表面,利用未标定摄像机获得受棋盘格标定板调制的变形格雷码条纹图像,通过局部单应性矩阵方法获得棋盘格标定板各角点所对应的投影仪图像坐标。根据摄像机图像坐标、投影仪图像坐标与棋盘格标定板角点对结构光测量系统进行标定,获得摄像机与投影仪的内参数矩阵以及投影仪图像坐标系在摄像机图像坐标系的位姿矩阵。最后对结构光测量系统进行了标定实验;并使用Samuel Audet标定工具箱、Douglas Lanman标定工具箱与提及的标定方法进行标定误差对比。实验结果表明该方法操作简便,精度高,能较好地标定结构光测量系统参数。

In the structured light measurement system,projector calibration has a direct impact on the accuracy of measurement for objects. In this paper,multiple orthogonal Gray Code are viewed on the checkerboard calibration plate through the projector. Then the deformed Gray Code stripe images are captured through uncalibrated camera. By the method of local homography matrix,the corresponding position of projector image coordinates for checkerboard calibration plate corners are obtained. Sturctured light measurement system calibration is based on the position of checkerboard calibration plate corners in camera image coordinates,and in projector image coordinates.Thus,the internal parameters matrix and the position and posture matrix of the projector coordinate system and camera coordinate system are obtained. Finally,structured light measurement system is calibrated by experiment.The calibration errors is contrasted with results of using Samuel Audet＇s Calibration Toolbox and Douglas Lanman＇s Calibration Toolbox. The experimental results show that the method is simple,high precise and the parameters of structured light measurement system can be calibrated very accurate.