三坐标测量机驱动的摄像机标定技术

为了降低摄像机的标定费用和提高标定精度,提出了一种基于三坐标测量机平动的摄像机标定技术,对该技术的原理、数学模型、标定步骤和标定精度进行了研究。根据摄像机标定的基本原理,利用三坐标测量机沿X、Y、Z轴移动和正交精度都很高的特点,以三坐标测量机带动待标定摄像机产生和白色陶瓷标准球球心(标定特征点)在X、Y、Z轴方向上的相对平动,得到标定特征点在测头坐标系中不同位置的坐标;在每一个确定位置,摄像机拍摄标定特征点的像,经图像处理后,计算出像点在计算机帧存坐标系中的坐标。引入测头坐标系,建立了该项摄像机标定技术的数学模型,给出了标定步骤,组建了标定系统。比对标定实验结果表明,基于三坐标测量机平动的摄像机标定系统与专用标定系统的标定精度相当,数据相差在±1μm以内,满足工程实际精度要求,成本低、标定效率高。

Camera calibration technology driven bythree-coordinate measuring machine

A CCD camera calibration technology based on the translation of a Coordinate Measuring Machine (CMM) is proposed to decrease the calibrating cost of CCD cameras and to improve the calibrating accuracy, and its principle, mathematic model, calibrating steps and calibrating accuracy are studied. According to the CCD camera calibration principle and the high translation accuracy of CMM, the CMM brings the CCD camera to be calibrated to produce the relative translation with respect to the center of a white ceramic standard sphere (the calibration characteristic point)along the X, Y, Z axes,then the coordinates of the different positions of the calibration characteristic point in the probe coordinate system can be obtained. Furthermore,by capturing the image of the white ceramic standard sphere by the camera at every position, the coordinates of different positions of the calibration characteristic points in a computer frame coordinate system can be registered after image processing. By introducing the probe coordinate system, a calibration mathematic model is established, the calibration steps are given and a calibration system is set up. The comparing calibration result shows that precision of the CCD camera calibration system based on the translation of CMM is equivalent to that of the special calibration system , and the difference between the calibrating data of the two systems is within ±1 μm, which meets the requirements of the practical calibration for low costs,higher accuracy and higher calibration efficiency.