一种基准关联的空间尺寸远心视觉测量方法

Telecentric Vision Measurement Method of Space Size Based on Datum Correlation

针对具有横截面外伸尖端特征的长轴工件,本文研究了一种基准关联的空间尺寸远心视觉测量方法。该方法首先利用远心成像实现较长尺度工件的局部待测要素的图像特征提取和位置测量,而后建立局部待测要素与相机成像视场以外的轴线基准要素的测量传递链,将局部要素经计算转化成全局径向尺寸,从而实现超过成像视场尺度的快速精密测量。构建了测量实验环境,对方法的有效性进行了验证,对误差进行了溯源和分析并给出了进一步提升精度的建议。本方法能够在远心平行投影条件下实现对立体工件的空间几何量测量,特别适用于对速度和精度均要求较高的在位测量应用场合。

This study investigated a spatial dimension telecentric vision measurement method based on benchmark correlation that aims at the long-axis workpiece with the characteristic of the protruding tip of the cross-section.First,telecentric imaging was used to realize the image feature extraction and position measurement of the local elements to be measured by the longer-scale workpiece.Then,a measurement transfer chain between the local elements and the axis reference elements outside the camera imaging field of view was established.The local element dimensions were converted into the global radial dimensions through calculations to achieve fast and accurate measurement beyond the scale of the imaging field of view.A measurement experiment environment was constructed to verify the effectiveness of this method,trace and analyze the error source,and give suggestions to further improve the accuracy.This method can realize the measurement of the spatial geometric quantity of the three-dimensional workpiece under the condition of telecentric parallel projection and is particularly suitable for on-site measurement applications that require high speed and accuracy.