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| Comparison of spatial circle fitting methods based on measuring data
collected from binocular stereo vision system |
| 1. Medical Imaging Department, Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, Jiangsu 215163, China; 2. University of Chinese Academy of Sciences, Beijing 100049, China |
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Abstract To find the optimal spatial circle fitting method in the measuring engineering application, the comparison of spatial circle fitting methods was completed based on the data collected from a binocular stereo vision system. According to the solving order and relevance of plane and spherical surface intersecting into a spatial circle, the existing five fitting methods were divided into three categories of solving plane and sphere together, solving plane and sphere independently and solving plane and sphere correlatively. The spatial circle fitting experiment was carried out to compare and analyze the performance and influence factors of fitting methods. Using the selfdeveloped binocular stereo vision system, three sets of spatial coordinates of a target making circular motion with multitooth dividing table were collected as fitting data, and the centerplane distance, the flatness and the roundness were used as fitting accuracy evaluation indexes. The experimental results show that the spherical surface needs the plane constraint to be solved correctly. The optimal fitting method is that the normal vector and constant coefficient of the plane are firstly solved by the leastsquare adjustment method, and then the center and radius of the sphere are solved by the coordinate system transformation or the perpendicular bisection plane method. The fitting accuracy can be improved by increasing the number of measurement points.
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Received: 01 August 2017
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2018, Vol. 39 
