针对一种立柱式二维移动视觉测量系统,提出了其数学模型的建立和标定方法。分析了测量原理和系统组成,并通过对运动定位和摄像机成像的独立建模,构建了符合测量原理的整体数学模型。标定时,在完成对定位误差等13项几何误差标定的基础上,通过移动摄像机使圆孔靶标的像平均分布在摄像机的像面上,根据靶标的工作台位置、像点坐标、以及测量时对应的运动机构移动量,利用最小二乘非线性拟合方法实现对摄像机成像模型参数的标定。实验结果表明:经建模和标定后,测量平均误差为1.8μm。利用该方法进行移动视觉测量系统的建模和标定,可以有效地保证系统的测量精度。
A mathematical model and calibration method is proposed for column two-dimensional portable vision metrology. The analysis of the measuring principle and system components is given. The overall mathematical model in line with measuring principle is established based on the exercise of independent positioning and camera imaging model. In the process of calibration, firstly, the calibration of geometric errors such as the positioning error is completed. Then, the image of round hole is evenly distributed in the image plane of the camera by moving the camera. At last, the calibration of camera imaging model parameters is achieved using nonlinear least squares fitting method, according to the target workbench position, pixel coordinates and the amount of the corresponding moving mechanism moves. Results show that the average error of measurement is 1.8μm by modeling and calibration. The modeling and calibration method of portable vision metrology can effectively improve the system accuracy.