给出了将改进的两步法与精确控制点相结合来精确校准立体像机的新技术,像机镜头畸变模型考虑了径向畸变和切向畸变。利用红外发光二极管随三坐标测量机测头移动以确定间距来形成立体校准模板上的精确控制点。校准程序包括先使用位于图像中心的控制点来线性求取部分校准参数,然后再使用所有控制点来迭代优化所有参数。实验中使用非线性优化参数来反推控制点的空间位置,发现精度比线性求解参数提高了0.11 mm,结果表明,此技术可以满足像机精确校准和测量的要求。

This paper presents a high-precision stereo camera calibration technique combined the improved two-step method with accurate control points,in which the lens distortion of a camera is modeled by a combination of radial distortion and tangential distortion.Accurate control points on a virtual stereo calibration pattern are formed by an infrared LED moved with the probe of CMM over a certain distance.The proposed calibration procedure involves direct linear solutions for most of the calibration parameters with the control points near the center of images,followed by some iteration and optimization solutions for all parameters with all control points.The accuracy of reconstructing control points with nonlinear optimization solutions is improved by 0.11 mm as compared with linear solutions.Experimental results show that the proposed technique can fulfil the goals of high-precision calibration and measurement of cameras.