双目视觉立体标定方法的改进

为了提高双目立体视觉系统中立体标定的精度,提出了一种利用正方形标定域中相互正交方向的消失点进行立体标定的新方法.首先摄像机从不同的方向拍摄平面标定板,在图像平面上确定一个正方形投影区域,再根据射影几何模型中的交比性质,计算出正方形中相互正交方向上的两对消失点;然后利用消失点与光心连线的射影几何性质,线性求解摄像机的全部内外参数;最后利用全局优化方法进行参数的优化.这一方法继承了张正友标定方法畸变模型的使用,实验利用MATLAB通过左右摄像机拍摄的两组图像对方法进行验证,实验结果表明,该方法的立体标定精度较高,且旋转矩阵R和平移向量T均符合实际要求;由于实验中正方形投影区域的大小及具体的位置关系是随机的,使其具有较好的实用性.

Improvement of stereo calibration of binocular vision method

To enhance the precision of stereo calibration,a new method for camera calibration using two pairs of vanishing points of orthogonal directions on testing square was proposed.First,a camera captured the template of the square from different directions; two vanishing points on parallel and diagonal directions on testing square were then determined by using the concept of cross ratio and harmonic conjugate in projective geometry.Second,all the intrinsic and external parameters were calculated linearly based on parallel property of a line of vanishing point connecting optical center.Finally,all the parameters were optimized by using global optimization method.The proposed method inherits the distortion model of Zhang Zhengyou calibration method,and is verified using two groups of images from left and right camera in MATLAB.Experiment results show that the method has high precision,and the rotation matrix R and the translation vector T conform to the actual requirements.Because the size of square projection area and the specific location are random,the method has good practicality.