基于液晶靶标的多CCD线结构光测量系统全局标定  

Global calibration of multi-CCD line-structured-light measurement system based on LCD target

作　　者：贾倩倩[1] 王伯雄[1] 赵博华[1] 罗秀芝[1] 

机构地区：[1]清华大学精密仪器与机械学系精密测试技术及仪器国家重点实验室,北京100084

出　　处：《光学精密工程》2009年第12期2990-2996,共7页Optics and Precision Engineering

基　　金：科技部中德科技合作重点项目(No.2003DFB00028)

摘　　要：为了对多CCD线结构光测量系统进行精确快速的全局标定,研究了一种基于液晶平面靶标的多CCD全局标定方法。首先,将液晶靶标放入光平面,在靶标上显示一系列特征点,然后进行各个CCD同步采集。通过时间序列对应特征点的图像坐标与靶标坐标,建立起像平面与靶标平面间的非线性模型,对形位关系已知的标准块进行测量,利用标准块的形位关系对像平面与靶标平面间的非线性模型进行优化,得到像平面与光平面间的映射关系,从而完成多CCD的全局标定。利用优化后的标定结果进行测量,结果表明,在自由曲面类物体的测量中,3个摄像机的数据拼接精度高,对标准块上特征点距离测量的RMS误差为0.217mm,角度测量的绝对误差为±0.2°。该方法快速简便,适合现场操作,已在多CCD线结构光测量系统中得到了实际应用。In order to realize the global calibration of a multiple CCDs line-structured-light measurement system, an approach to calibrate multiple CCDs based on a LCD target is investigated. Firstly, the LCD target is arranged at the position of light section,and the characteristic points are shown on the target one by one, then they are captured by cameras at the same time. The relationship between the target coordinate and the image coordinate is established in a nonlinear model through synchroni zing pulses, and the model is optimized by the shape restraints of a calibrating part to get the mapping between the light sectioning plane and the image plane. So far,the global calibration is achieved successfully. Measurements of free surface show that the data from different CCDs are well spliced in the light sectioning plane, and measurements of the calibrating part show that the RMS error in a distance is 0.2 mm and the absolute error in a angle is ±0.2°. This method is easy to use, and has been ap plied to a multi CCD 3D measurement system.

关 键 词：多摄像机 线结构光 液晶靶标 全局标定 优化 

分 类 号：TP391[自动化与计算机技术—计算机应用技术] TP212.14[自动化与计算机技术—计算机科学与技术]