基于立体视觉的光度立体LED光源位置参数标定方法

Stereo Vision-based Calibration Approach for Position Parameters of LED in Photometric Stereo

针对光度立体视觉中基于镜面反射的光源位置标定法操作复杂及误差较大等问题,提出了一种基于立体视觉的LED光源位置参数标定方法。利用双目立体视觉系统依次拍摄光度立体中的LED光源,利用基于立体视觉成像矩阵的最小二乘法计算光源的空间三维坐标,通过光度立体与双目立体视觉系统中摄像机的旋转平移关系,联立得到光源位置标定系统结构参数,进而获得光度立体中LED光源相对于摄像机的空间位置关系。实验结果表明:所提方法可以有效地解决镜面反射标定法操作繁琐的问题,与基于镜面反射的方法相比,所提方法通过操作方便的立体视觉系统即可获得精度更高的LED光源位置标定参数,得到的光源对角线距离的平均绝对误差(MAE)和均方根误差(RMSE)与镜面反射方法相比有较大程度的减小。

Focusing on the problems of complex operation and large error of the light source position calibration method based on specular reflection in photometric stereo vision, this paper proposes a method of light-emitting diode(LED)light source position parameter calibration based on stereo vision. In photometric stereo, the LED light source is photographed using binocular stereo vision system, and the three-dimensional coordinates of the light source are calculated using the least square method based on the stereo vision imaging matrix. Simultaneously, the structural parameters of the light source position calibration system are obtained through the rotation and translation relationships between the cameras in the photometric stereo and binocular stereo vision systems, and the spatial position relationship of the LED light source, which is relative to the camera in the photometric stereo system, is obtained. The experimental result shows that the proposed method can effectively solve the problem of the cumbersome operation of the specular reflection calibration method, and when compared to the method based on specular reflection, the proposed method can obtain more accurate LED light source position calibration parameters using the easy-to-operate stereo vision system.The mean absolute error(MAE) and root mean square error(RMSE) of the light source diagonal distance obtained by the proposed method are lower than those obtained by the specular reflection method.