High-resolution method for locating round objects in large-distortion image
Zhanghua Huang, Hao Zhang, Meng Li, Huaiyu Cai · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2002
Accurate object location is a key problem in image measurement system and the basis of other image processing procedures. In our project, we aim to locate some chromatic round objects in a large field. In this paper, the regions where the objects lie are isolated firstly from the original image using their color information, in which the edges of objects are detected. A novel fast method for fitting an ellipse to the edge points in the region is presented, by which the geometric distortion is calibrated by the ellipse model calculated linearly according to the position of the region. And the position of object with the precision of one pixel is obtained through edge fitting. Finally the accurate data in 1/5 pixel result from subpixel subdivision.