基于非标定摄像机的尺寸测量方法

针对小工件的非接触长度测量,提出了一种基于交比不变,利用非标定CCD摄像机与已知特征标记物进行小工件长度测量的新方法.利用摄像机对工件的图像信息进行远距离采集,建立测量模型,在对图像进行预处理的基础上行边缘识别,提取工件与已知特征标记物边缘特征,进而实现工件长度的在线测量,并与经标定摄像机的在线测量结果进行比较,结果表明,该测量方法操作简单,无需标定摄像机的同时适应性强,被测工件长度在0～500 mm,测量误差低于0.4％.

Size measurement method based on non calibrated camera

To get the size of small work pieces by non-contact means, a new method is proposed in this paper which is based on the invariance of cross ratio with non-calibrated CCD cameras. After the images of work pieces being remotely acquired by camera and preprocessed, edges as well as some other features of the work piece will be detected and extracted. According to two orthogonal sets of parallel line markers with known spacing on the measuring table, the size of the work piece is obtained. Experimental results indicate that this kind of method used in length measurement system has similar precision to the traditional techniques which first of all must have their cameras calibrated. At the same time it can be simply operated and adapted to various situations. The measured length of work pieces ranges from 0mm to 500 mm and the measuring error is less than 0.4％.