Selami Yassine, Tao Wei, Gao Qiang, Yang Hongwei, Zhao Hui
Department of Instrument and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
Sensors (Basel). 2018 Feb 7;18(2):504. doi: 10.3390/s18020504.
Laser triangulation allows non-contact measurement in the third dimension. Due to the nonlinearities presented in camera and laser sensor, large range distances are quite difficult to measure with high precision. In order to enhance the precision and accuracy of large range measurement based on laser triangulation, we propose a novel scheme composed of four laser emitters, curve fitting subpixel location algorithm for laser center detection, and the linear regression approach based on the Gaussian model for calibration. When an object performs a 100 mm displacement from a closer to a farther point, our system achieved a repeatability up to ±7 µm, an estimated standard deviation of fitting error within 0.0027 mm, an expanded uncertainty of repeatability within 0.13 mm, an average error variation of rotational plane within 0.15 degree and a nonlinearity error within ±0.04% in full scale. Compared to published results, our proposed method shows an enhancement in accuracy. The error is significantly reduced and maintains at the low level for large ranges, which makes this system applicable and suitable for industrial and indoor applications.
激光三角测量法可实现三维非接触测量。由于相机和激光传感器存在非线性，大范围内的距离很难高精度测量。为提高基于激光三角测量的大范围测量精度和准确性，我们提出一种新颖方案，该方案由四个激光发射器、用于激光中心检测的曲线拟合亚像素定位算法以及基于高斯模型的线性回归校准方法组成。当物体从较近点向较远点位移100毫米时，我们的系统实现了高达±7微米的重复性、拟合误差估计标准偏差在0.0027毫米以内、重复性扩展不确定度在0.13毫米以内、旋转平面平均误差变化在0.15度以内以及满量程非线性误差在±0.04%以内。与已发表结果相比，我们提出的方法在精度上有提升。误差显著降低且在大范围下保持在低水平，这使得该系统适用于工业和室内应用。
