Improving parametric active contours by using object center of gravity distance map

Abstract

In this paper, we propose an improvement of the classical parametric active contours. The method, presented here, consists in adding a new energy term based on the object center of gravity distance map. This additional term acts as attraction forces that constrain the contour to remain in the vicinity of the object. The distance map introduced here differs from the classical one since it is not based on a binary image, but rather constitutes a simplified and very fast version that relates only to one point, defined as the expected center of gravity of the object. The additional forces, so introduced, act as a kind of balloon method with improved convergence. The method is evaluated for object segmentation in images, and also for object tracking. The center of gravity is computed from the initial contour for each image of the sequence considered. Compared to the balloon method, the presented approach appears to be faster and less prone to loops, as it behaves better for object tracking.