High accuracy measurement model of laser triangulation method
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摘要: 为提高检测准确性，提出激光三角法高精度测量模型，由变阈值亚像素灰度重心提取算法和CCD倾角误差补偿模型两部分组成；光斑中心定位算法对激光检测准确度起关键作用，针对已有激光中心定位算法的缺陷，提出了变阈值亚像素灰度重心提取算法，通过梯度函数和高斯拟合算法设定阈值去除光斑边缘噪声区域对中心定位的影响，并利用多项式插值提高灰度重心法精度；同时为提高实际工业生产环境中的测量准确性，建立CCD倾角误差补偿模型；应用激光三角法高精度测量模型，以STM32F407为硬件核心建立系统，以锥螺纹为被测物进行实验；实验结果表明：该测量模型实现了对锥螺纹信息的准确采集，且精度明显高于传统的灰度重心法，可以将锥螺纹检测的误差控制在10 m内。Abstract: In order to improve the measurement accuracy, the high accuracy measurement model of laser triangulation method was proposed, which consisted of variable threshold subpixel grayscale gravity center extraction algorithm and CCD tilt error compensation algorithm. The spot centering algorithm played a decisive role in the accuracy of laser detection. A variable threshold subpixel grayscale gravity center extraction algorithm was proposed according to the defect of the existing laser center localization algorithm. The gradient function and the Gaussian fitting algorithm were used to set the threshold to remove the effect of spot edge noise region on center location, and the polynomial interpolation were used to improve the precision of grayscale gravity method. CCD tilt error compensation algorithm was established to further improve accuracy. The system was established with STM32F407 as the hardware core. Taking taper thread as the measured object, the test was carried out. The results show that the laser spot can be accurate acquisition by the high accuracy measurement model. Precision is obviously higher than the traditional grayscale gravity center method, and successfully controls the error within 10 microns.
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Key words:
- laser measurement /
- laser spot center /
- error compensation /
- single chip microcomputer
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