Li Weimin, Jin Jing, Li Xiaofeng, Li Bin
Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, 96#, Jing Zhai Road, Hefei, Anhui Province, China.
Appl Opt. 2010 Feb 20;49(6):1001-6. doi: 10.1364/AO.49.001001.
We propose a method of rotation angle measurement with high precision in machine vision. An area scan CCD camera, imaging lens, and calibration pattern with a spot array make up the measurement device for measuring the rotation angle. The calibration pattern with a spot array is installed at the rotation part, and the CCD camera is set at a certain distance from the rotation components. The coordinates of the spots on the calibration pattern is acquired through the vision image of the calibration pattern captured by the CCD camera. At the initial position of the calibration pattern, the camera is calibrated with the spot array; the mathematical model of distortion error of the CCD camera is built. With the equation of coordinate rotation measurement, the rotation angle of the spot array is detected. In the theoretic simulation, noise of different levels is added to the coordinates of the spot array. The experiment results show that the measurement device can measure the rotation angle precisely with a noncontact method. The standard deviation of rotation angle measurement is smaller than 3 arc sec. The measurement device can measure both microangles and large angles.
我们提出了一种在机器视觉中进行高精度旋转角度测量的方法。一个面阵CCD相机、成像镜头以及带有光斑阵列的校准图案构成了用于测量旋转角度的测量装置。带有光斑阵列的校准图案安装在旋转部件上，CCD相机设置在距旋转部件一定距离处。通过CCD相机捕获的校准图案的视觉图像获取校准图案上光斑的坐标。在校准图案的初始位置，用光斑阵列对相机进行校准；建立CCD相机畸变误差的数学模型。利用坐标旋转测量方程，检测光斑阵列的旋转角度。在理论模拟中，向光斑阵列的坐标添加不同水平的噪声。实验结果表明，该测量装置能够通过非接触方法精确测量旋转角度。旋转角度测量的标准偏差小于3角秒。该测量装置既能测量微小角度，也能测量大角度。
