为了准确测量待检测物体厚度,提出了基于远心镜头的主动式激光三角测距的方法。而远心镜头采用平行投影的方式,使得像点位移与物体高度变化之间呈现线性关系,在此基础上建立了基于远心镜头的主动式激光三角测距模型,探讨了光学系统误差、机器装置误差、图像处理误差等影响精度的因素。实验结果表明,利用基于远心镜头的主动式激光三角测距的方法和补偿插值法得到的厚度测量平均误差能够达到5 μm以内。

An active laser triangulation method based on the telecentric lens is proposed to accurately measure the thickness of the object. The parallel projection method applies to the telecentric lens, and thus the relationship between the image point displacement and the object height change is linear. We establish a model of active laser triangulation based on the telecentric lens, and discusses the factors that influence the accuracy, including optical system error, machine error, and image processing error. In the experiment, we get the mean error less than 5 μm for thickness measurement when combing the active laser triangulation based on the telecentric lens and the compensation interpolation method.