| || Object Area-based Method for Elliptic and Circular Fit of a Two-tone Image
Author : Chaudhuri, D.
Source : Defence Science Journal ; Vol:58(6) ; 2008 ; pp 710-714
Subject : 532.542 Fluid Dynamics
Keywords : Circularity;Ellipticity;Morphometry;Shape analysis;Pattern recognition;Target detection
Abstract : Circular or elliptic fit of an object is important in target detection, shape analysis, and biomedical image analysis problems. Here, the problems of fitting circle or ellipse to an object in 2-D are considered. At first, the problem is converted to quadratic equation of single unknown by some constraints. Then its solutions for all the border points of the object are found and averaged. The major and minor axes of ellipse are presented by least sum perpendicular distance of all points of the object. The other unknowns are found using the equations of constraints. In the proposed method, the main constraint used for the circular and elliptic fit is that the area of the fitting circle or ellipse is equal to the area of the object to be fitted. The approach appears to be less sensitive to the object border noise and is computationally attractive. Some examples are presented to show the effectiveness of the approach. A measure of degree of circularity, ellipticity, etc in fuzzy set theoretic framework is also proposed.