Subpixel localization algorithm of circle parameters based on still image of small parts
Yuan Feng · Journal of Jilin University · 2009
Subpixel algorithm is an effective method to improve the error of edge location under assured hardware condition.Aiming at the circle parameters detection of small size parts in industry,a novel algorithm for subpixel location of circle parameters was proposed based on Zernike moments,quadratic polynomial interpolation and least-squares method.First,orthogonal circle operator was modeled in terms of Zernike orthogonal complex moment;the one-to-one mapping between the edge point and the parameters of the circle was established by the algorithm.Then,quadratic polynomial interpolation was adopted to further locate the edge points in the gradient direction.Finally,the subpixel-level circle parameters can be obtained by fitting the edge points using least-square method.Experiments were conducted on small circular inertial device to validate the algorithm and to study its detecting precision.Results show that the detecting precision is higher than traditional operators and the algorithm is very effective in detecting subpixel-level circle edges for real-time online measurement.