摘要
To eliminate rotation deviation of sequential images mosaic when measuring linear dimensions of large scale parts with computer vision, a novel algorithm based on the chain code searching method is proposed. After image preprocessing, including image filtering, image segmentation, and edge detection, the chain code length of the contour line can be searched out by the proposed method. Then, the angle from the contour line to the coordinate axis is computed with the length of the contour line. After that, the sequence is rotated in the opposite direction and the rotation deviation is eliminated. It is prepared for the next mosaic of sequences in eliminating shifting deviation. Experiments are carried out on parts with a linear profile rotating angle from 0° to 9°. The results show that compared with the commonly used Hough transform, the new method has higher precision and faster speed, which is important in realizing online high precision measurements of large scale parts with a linear profile.
在用机器视觉在线自动测量大尺寸零件的直线轮廓尺寸时,为了消除序列图像拼接中的旋转偏差,提出了一种基于链码搜索的新算法.将序列图进行滤波、分割、边缘提取预处理后,搜索边缘轮廓线的链码长度,根据链码长度求出轮廓线与坐标轴间的夹角,将序列图反向旋转这一角度,使序列图中直线轮廓方向与坐标方向一致,从而消除了序列图的旋转偏差,为后续拼接中消除平移偏差做好准备.对旋转偏差为0°～9°的线性轮廓零件进行了实验,结果表明:与经典的Hough变换相比,新方法精度更高,速度更快,这对实现大尺寸直线轮廓零件在线高精度测量具有重要实用价值.
基金
The National Natural Science Foundation of China(No.50805023)
the Program for Special Talent in Six Fields of Jiangsu Province(No.2008144)
Jiangsu Provincial Science and Technology Achievement Transformation Project(No.BA2010093)
