Real-Time Camera Tracking for Mobile Devices: The VisiTrack System

This paper presents VisiTrack, a novel approach for video based incremental tracking in real-time. The major objectives in the development of VisiTrack was to design or select algorithms that are well suited for embedded real-time computation. We had a special focus on latency reduction and storage minimization since the algorithms should run on mobile devices like PDAs with the appropriate extension, i.e. mainly a camera, in real-time. The image analysis, camera localization and feature position approximation of VisiTrack are explained in detail. The CV-SDF model, an extension of Synchronous Dataflow graphs (SDF), supporting the principles of linear processing and fine-grained pipelining was defined and applied for the design of all VisiTrack modules in order to fulfill real-time constraints and reduce system latency. Furthermore the camera localization and position approximation include mechanisms for minimization of errors that may arise for instance due to measurement inaccuracies. Current applications of VisiTrack in the augmented reality domain and robotic self localization show its good performance. However VisiTrack is not limited to these application domains.