光笔式单摄像机三维坐标视觉测量系统建模

Model of a Light Pen Single Camera 3-D Coordinate Vision Measurement

提出了一种光笔式单摄像机三维坐标视觉测量系统,其主要由光笔、摄像机和笔记本电脑组成。测量时,使笔尖测头接触被测物体表面,摄像机摄取笔体上3个发光二极管的像,由3个发光二极管的像面坐标就可计算出被测点的三维坐标。运用三点透视问题(P3P)原理建立了系统的数学模型,并用摄像机模型中的坐标变换原理证明了该模型解的唯一性,推导出了被测点坐标的求解公式。在三坐标测量机上做了对比实验,结果表明,该系统达到了大尺寸现场测量要求的精度。

A light-pen single camera 3-D coordinate vision measurement system is proposed in this paper. It mainly consists of a light pen,a CCD camera and a laptop. When measuring,the probe of the light pen contacts the measured point,the CCD camera takes the image of LEDs on the light pen,and the 3D coordinates of the measured point are obtained by computing the coordinates of LEDs in the image plane. Based on the prindple of perspective-three-point problem（P3P）, the system＇s mathematical model is established. The uniquencess of the modd＇s solution is verified using the coordinate transform method in Camera＇s model, and the analytical equations of the measured point＇s coordinates are derived. The comparative experiment is conducted on the CMM,and the result shows that the measurement accuracy of this system can meet the requirement of large dimension measurement on spot.