Adaptive Search Window for Object Tracking in the Crowds using Undecimated Wavelet Packet Features

Abstract

In this paper, we propose an adaptive object tracking algorithm in crowded scenes. The amplitudes of of Undecimated Wavelet Packet Tree coefficients for some selected pixels at the object border are used to create a Feature Vector (FV) corresponding to that pixel. The algorithm uses these FVs to track the pixels of small square blocks located at the vicinity of the object boundary. The search window is adapted through the use of texture information of the scene by finding the direction and speed of the object motion. Experimental results show a good object tracking performance in crowds that include object translation, rotation, scaling and partial occlusion.

Object Tracking in Crowded Video Scenes Based on the Undecimated Wavelet Features and Texture Analysis

“…(2) Long-duration occlusion originates from the fact that the object of interest and the occluding object both move at the same direction. Since the algorithm uses activity analysis to find the motion and direction of the search window and hence updates the search window location, it can predict the location of the object after occlusion [29,32]. Therefore, our updating mechanism ensures that the object lies within the search window in case of occlusion, and our robust FV allows for successful tracking afterward.…”

“…In the first step, the wavelet packet tree for the desired object in the reference frame is generated by the UWPT. As mentioned in the previous section, the UWPT has two properties that make it suitable for generating invariant and robust features in image processing applications [26][27][28][29][30][31].…”

“…The main contribution of this paper is the adaptation of a feature vector generation and block matching algorithm in the UWPT domain [26] for tracking objects [27,28] in crowded scenes in presence of occlusion [29] and noise [30,31]. In addition, it uses an interframe texture analysis scheme [32] to update the search window location for the successive frames.…”