基于单目视觉的自由曲面三维坐标测量方法

3D coordinate measurement methods of free-form surface based on monocular vision

本文将单摄像机与三坐标测量机结合设计了一种自由曲面的三维坐标测量方法。自由曲面的表面经坐标测量机带动摄像机序列采集图像后形成图像体积,然后使用调焦评价函数在图像体积内寻优判断,找到自由曲面的正焦图像表面。根据物像关系式和正焦图像表面即可推得自由曲面点的三维坐标。经实验比较,本系统测量结果与接触式坐标测量机测量曲面点Z坐标极限偏差13μm。

A 3D coordinate measurement method of free-form surface was designed, which combines 3D coordinate measuring machine with single camera. The coordinate measuring machine drives the camera to capture the free-form surface image sequentially and form the image volume. Then the focused image surface （FIS） of the free-form surface is determined by searching for a shape that optimizes the focus evaluation function in the image volume. According to FIS and the object-image relation, the 3D coordinates of the free-form surface are obtained. Experiment shows that the maximum deviation of Z coordinates measured by this system and ordinary contacting coordinate measuring machine is 13μm.