基于射影变换的结构光测量系统中投影仪标定方法

Projector Calibration Method Based on Projective Transformation for Structured Light Measurement System

在结构光三维轮廓测量系统中,对参数的标定是测量的首要关键技术,但投影仪参数的标定目前还存在着标定精度低等问题。提出了一种简便、高精度的投影仪标定方法,该方法通过投影圆点图案到一块本身带有圆形标志点的平板上实现。根据射影变换原理建立投影仪图像和摄像机图像的基本对应关系,然后对基本对应关系的误差使用二元四次函数拟合并进行补偿的方法建立两者的准确对应关系,进而获得平板上圆形标志点在投影仪上的准确图像坐标,完成投影仪标定。仿真和实验结果表明,提出的投影仪标定方法有较高的精度,其中实验验证投影仪标定误差最大值小于0.1pixel,有效值小于0.03pixel,系统测量精度可达0.06mm。

For structured light measurement system,parameter calibration is the key technique of measurement.However the accuracy of projector parameters calibration is low.A simple,convenient and accurate method is put forward,which is done by projecting circles pattern to a flat with circular signalized points.Fundamental corresponding relation is established between projector image and camera image based on projective transformation theory.After that accurate corresponding relation is established by using bivariate quartic function to fit and compensate error.It is obtained for the accurate projector image coordinates of circular signalized points on the flat.Then,projector calibration is accomplished.Simulation and experimental results demonstrate that the proposed method can get better precision,and experiments verify that the maximum value and efficient value of projector calibration error is less than 0.1 and 0.03 pixel,respectively,and the system measurement precision is about 0.06 mm.