优化的PSO空间高精度线结构光直接标定法

Optimized PSO Space High-precision Line Structured Light Direct Calibration Method

线结构光测量系统的立体标定是进行三维测量的必要环节,其标定精度直接决定三维测量的精度。针对目前线结构光标定存在的计算过程复杂、局限性大、成本高、精度低等问题,提出了一种空间高精度线结构光直接标定法。设计异形标定块,通过DBSCAN算法剔除标定块线激光条纹上的噪声点与边界点,然后利用改进的PSO算法优化最短路径寻优的目标函数,提取线激光条纹上的特征标定点,建立像素坐标与世界坐标之间的映射关系表,从而直接获取待标定点像素坐标对应的世界坐标,或通过距离待标定点最近的三个特征标定点计算出关系转换矩阵,获取待标定点的世界坐标。试验表明,优化后的PSO算法寻优能力提升了27.23%,收敛速度提升了66.67%,特征标定点的提取误差约为0.4个像素,线结构光测量系统标定后,沿x方向的平均绝对测量误差为0.015 6 mm,沿z方向的平均绝对测量误差为0.017 4 mm。

The three-dimensional calibration of the line structured light measurement system is a necessary part of the three-dimensional measurement. Its calibration accuracy directly determines the accuracy of the three-dimensional measurement. The calculation process for the current line structure cursor positioning is complicated, limited, high cost, low precision, etc. Problem, this paper proposes a direct calibration method of spatial high-precision line structured light. Design a special-shaped calibration block, remove the noise points and boundary points on the line laser stripe of the calibration block through the DBSCAN algorithm, then use the improved PSO algorithm to optimize the objective function of the shortest path optimization, extract the characteristic calibration points on the line laser stripe, and establish the pixel coordinates The mapping relationship table with the world coordinates, so as to directly obtain the world coordinates corresponding to the pixel coordinates of the point to be calibrated, or calculate the relationship conversion matrix through the three characteristic calibration points closest to the point to be calibrated to obtain the world coordinates of the point to be calibrated. Experiments show that the optimized PSO algorithm′s optimization ability has increased by 27.23%, the convergence speed has increased by 66.67%, and the extraction error of the feature calibration point is about 0.4 pixels. After the linear structured light measurement system is calibrated, the direction along the x direction The average absolute measurement error is 0.0156 mm, and the average absolute measurement error along the z direction is 0.0174 mm.