Mean Shift tracking with multiple reference color histograms

The Mean Shift tracker is a widely used tool for robustly and quickly tracking the location of an object in an image sequence using the object’s color histogram. The reference histogram is typically set to that in the target region in the frame where the tracking is initiated. Often, however, no single view suffices to produce a reference histogram appropriate for tracking the target. In contexts where multiple views of the target are available prior to the tracking, this paper enhances the Mean Shift tracker to use multiple reference histograms obtained from these different target views. This is done while preserving both the convergence and the speed properties of the original tracker. We first suggest a simple method to use multiple reference histograms for producing a single histogram that is more appropriate for tracking the target. Then, to enhance the tracking further, we propose an extension to the Mean Shift tracker where the convex hull of these histograms is used as the target model. Many experimental results demonstrate the successful tracking of targets whose visible colors change drastically and rapidly during the sequence, where the basic Mean Shift tracker obviously fails.