Abstract

Abstract. Visual tracking is a challenging problem, as an object may change its appearance due to viewpoint variations, illumination changes, and occlusion. Also, an object may leave the field of view and then reappear. In order to track and reacquire an unknown object with limited labeling data, we propose to learn these changes online and build a model that describes all seen appearance while tracking. To address this semi-supervised learning problem, we propose a cotraining based approach to continuously label incoming data and online update a hybrid discriminative generative model. The generative model uses a number of low dimension linear subspaces to describe the appearance of the object. In order to reacquire an object, the generative model encodes all the appearance variations that have been seen. A discriminative classifier is implemented as an online support vector machine, which is trained to focus on recent appearance variations. The online co-training of this hybrid approach accounts for appearance changes and allows reacquisition of an object after total occlusion. We demonstrate that under challenging situations, this method has strong reacquisition ability and robustness to distracters in background.

Abstract-We present here a real time active vision system on a PTZ network camera to track an object of interest. We address two critical issues in this paper. One is the control of the camera through network communication to follow a selected object. The other is to track an arbitrary type of object in real time under conditions of pose, viewpoint and illumination changes. We analyze the difficulties in the control through the network and propose a practical solution for tracking using a PTZ network camera. Moreover, we propose a robust real time tracking approach, which enhances the effectiveness by using complementary features under a two-stage particle filtering framework and a multi-scale mechanism. To improve time performance, the tracking algorithm is implemented as a multi-threaded process in OpenMP. Comparative experiments with state-of-the-art methods demonstrate the efficiency and robustness of our system in various applications such as pedestrian tracking, face tracking, and vehicle tracking.

We address the problem of automatic face detection and tracking in uncontrolled scenarios using a pan-tilt-zoom (PTZ)

Abstract