双目结构光三维测量不确定度的Monte Carlo评定方法

Monte Carlo Evaluation Method for Uncertainty of Three-dimensional Measurement System Based on Binocular Structured Light

摘要:

由于多频外差法的双目结构光三维测量系统的参数模型具有复杂的非线性特征，传统方法很难实现其测量不确定度的准确评定。针对此问题提出了双目结构光三维测量系统的蒙特卡洛评定方法(Monte Carlo Method，MCM)。首先，根据各坐标系转换关系和多频外差法原理建立三维测量模型，分析主要误差源对测量结果的影响；其次，建立各不确定度分量的概率密度函数，获得各参数的分布规律；最后，建立测量系统各参数与被测件表面参数之间的MCM模型，通过大规模随机数值模拟，实现测量结果不确定度评定。为了验证本文方法的有效性，用标准球和标准量块进行实验。测量数据表明，通过MCM得到的结果均能包含标准量具的标称值范围，评价结果准确。

Abstract:

Due to the complex nonlinear characteristics of the parameter model in a three-dimensional measurement system based on binocular structured light and the multi-frequency heterodyne method, traditional approaches face difficulties in accurately evaluating measurement uncertainty. Therefore, the Monte Carlo method is used to evaluate the uncertainty of the binocular structured light 3D reconstruction system. Firstly, a three-dimensional measurement model is established according to the conversion relationship of each coordinate system and the principle of multi-frequency heterodyne method, and the influence of main error sources on the measurement results is analyzed. Then, probability density functions of uncertainty components are derived to obtain the distribution of each parameter. Finally, the Monte Carlo model between parameters of the measurement system and surface parameters of the measured object is established, and the uncertainty of the measurement results is evaluated by large-scale random numerical simulation. To verify the effectiveness of the proposed method, experiments are conducted on the standard sphere and standard gauge blocks. The measurement data show that all the results obtained by Monte Carlo method can contain the nominal range of the eigenvalues of standard measuring tools, and the evaluation results are accurate.