Research on the extraction of quasi-circular object contours using active contour model in polar coordinate

In this paper, we present the active contour model in polar coordinate with a new internal energy term corresponding to the particularity of the quasi-circular object. The energy functional is minimized by the dynamic programming method. A precise initial contour is not necessary in this model which is different from the typical model. The proposed approach is robust to local minima because it searches the whole energy space. Another advantage of this model is that it searches the solution only once, which is different from the iterative method of the traditional model. The approach is tested on synthetic and real images. Results show that the model is robust to local minima and location of the center point.