Multi-camera multi-object voxel-based Monte Carlo 3D tracking strategies

This article presents a new approach to the problem of simultaneous tracking of several people in low-resolution sequences from multiple calibrated cameras. Redundancy among cameras is exploited to generate a discrete 3D colored representation of the scene, being the starting point of the processing chain. We review how the initiation and termination of tracks influences the overall tracker performance, and present a Bayesian approach to efficiently create and destroy tracks. Two Monte Carlo-based schemes adapted to the incoming 3D discrete data are introduced. First, a particle filtering technique is proposed relying on a volume likelihood function taking into account both occupancy and color information. Sparse sampling is presented as an alternative based on a sampling of the surface voxels in order to estimate the centroid of the tracked people. In this case, the likelihood function is based on local neighborhoods computations thus dramatically decreasing the computational load of the algorithm. A discrete 3D re-sampling procedure is introduced to drive these samples along time. Multiple targets are tracked by means of multiple filters, and interaction among them is modeled through a 3D blocking scheme. Tests over CLEAR-annotated database yield quantitative results showing the effectiveness of the proposed algorithms in indoor scenarios, and a fair comparison with other state-of-the-art algorithms is presented. We also consider the real-time performance of the proposed algorithm.Peer ReviewedPostprint (published version

An Appearance-based Particle filter for Visual Tracking in Smart Rooms

This paper presents a visual particle filter for tracking avariable number of humans interacting in indoor environments, using multiple cameras. It is built upon a 3-dimensional, descriptive appearance model which features (i) a 3D shape model assembled from simple body part elements and (ii) a fast while still reliable rendering procedure developed on a key view basis of previously acquired body part color histograms. A likelihood function is derived which, embedded in an occlusion-robust multibody tracker, allows for robust and ID persistent 3D tracking in cluttered environments. We describe both model rendering and target detection procedures in detail, and report a quantitative evaluation of the approach on the 'CLEAR'07 3D Person Tracking' corpus