Head tracking using shapes and adaptive color histograms

A new method is presented for tracking a person's head in real-time. The head is shaped as an ellipse, and the adaptively modified RGB color histogram is used to represent the tracked object (head). The method is composed of two parts. First, a robust nonparametric technique, called mean shift algorithm, is adopted for histogram matching to estimate the head's location in the current frame. Second, a local search is performed after histogram matching to maximize the normalized gradient magnitude around the boundary of the elliptical head, so that a more accurate location and the best scale size of the head can be obtained. The method is demonstrated to be a real-time tracker and robust to clutter, scale variation, occlusion, rotation and camera motion, for several test sequences.