A robust parametric active contour model for target tracking using modified energies: Virtual electric field and motion-based balloon

Active contour model (ACM) is a powerful tool for the target tracking in digital image sequences. Traditional ACM fails to track the targets when target displacements or aspect changes are high and inhomogeneous. In order to improve these inefficiencies, in this paper, a modified balloon energy in the parametric ACM is defined base on target displacement in two successive frames to inflate some suitable points adaptively and locally, in the current frame. Moreover, traditional ACM suffers from low capture range, so it can not attract to the concave boundaries of the target those results to an uncertain tracking in image sequences. To improve this inefficiency, a modified virtual electric field energy is used in conjunction with the proposed balloon energy. Also, new ACM algorithm adapted base on mutual changes of target and background gray levels. The advantages of the proposed ACM consist of: less sensitivity to initialization, large capture range, attraction to sharp-pointed and concave boundaries of target, ability of tracking the target with large and inhomogeneous displacements, and acceptable computational cost. Experimental results show that the tracking by the proposed ACM based on the greedy algorithm produces more correct detection percent of the target boundaries than other similar methods, in different circumstances.