基于双目立体视觉的系统模型,设计了一种新型的光笔, 提出了基于该光笔的匹配算法。由于光笔在测量时可以出现任何姿态, 必须对两摄像机像面上所成图像中的8个发光点进行匹配, 才能代入摄像机模型计算出8个发光点在左摄像机坐标系下的三维坐标, 通过建立8个共面发光点所在的平面坐标系与左摄像机坐标系的线性关系求得测头中心的三维坐标。实验结果表明, 系统在5 m范围内的空间长度测量精度达到0.159 mm ,基本满足大尺寸工件的现场检测需求。

A novel light-pen is designed based on the two-light pen-camera type 3D-coordinate measuring system and a stereo matching algorithm is proposed. The light-pen may be any of the gestures, so eight LEDs light sources of the image are matched. And then 3D coordinates of eight LEDs of the left camera are calculated by the camera model. 3D coordinate of the tip of the pen is achieved by using the linear relationship between the 2D coordinate system containing eight LEDs and the 3D coordinate system of the left camera. Experimental results prove that, as the accuracy came to 0.159 mm at the range of 5 m, the system basically meets the needs of the large workpieces.