基于双目视觉的薄壁零件变形量测量

针对薄壁零件变形量测量困难且过程繁琐的问题,提出了一种基于双目视觉的薄壁零件变形量测量方法 .对于零件表面变形量的测量,将具有基准坐标系标记点的刚性金属块安装在被测零件上,并在零件表面粘贴多个设计的编码标志点和彩色圆形定位点.利用彩色标记点分割出基准坐标系和编码标记点的有效图像区域,排除干扰图像特征.进行基准坐标系标记点和编码标记点的识别和检测,利用设计的角点结构实现标记点圆心的精确定位,并计算得到测量点的三维坐标.在基准坐标系下,通过计算零件变形前后表面关键点的三维坐标变化得到工件表面变形量.对于零件边缘变形,采用改进Canny边缘检测算法提取零件边缘的有效轮廓信息,并利用极线几何约束和灰度相似性对边缘特征进行了立体匹配和三维重建.薄壁零件变形量测量实验和测量精度验证实验表明该测量方法合理有效且测量精度满足要求.

Deformation Measurement of Thin-walled Part Based on Binocular Vision

Aiming at the problem that the deformation measurement of thin-walled part is difficult and complicated,a method of deformation measurement of thin-walled part based on binocular vision is proposed. For the surface deformation of the part,a rigid metal block with reference coordinate system markers is installed on the measured part,and the designed coded targets and color circular markers are pasted on the surface of the part. The effective image region of the reference coordinate system and the coded targets are segmented by the color circular markers,which can eliminate the interferential image features. The identification and detection of coordinate system markers and coded targets are carried out,which realizes the accurate location of centers by using the designed corner structure,and then the 3 D coordinates of the measurement points are calculated. The surface deformation of the part is calculated by comparing the changes of the 3 D coordinates of the measurement points before and after part deformation.For the edge deformation of part,the improved Canny algorithm is used to extract the edge contour information of part,then the stereo matching and 3 D reconstruction are carried out based on epipolar constraint and gray similarity. The experimental results show that the measurement method is reasonable and effective,and the measurement accuracy meets the requirements.