Sampling methods for tracking and detecting multiple objects


The recently proposed CONDENSATION algorithm and its variants enable the estimation of arbitrary multi-modal posterior distributions that potentially represent multiple tracked objects. However, the specific state representation adopted in the earlier work does not explicitly supports counting, addition, deletion and occlusion of objects. Furthermore, the representation may increasingly bias the posterior density estimates towards objects with dominant likelihood as the estimation progresses over many frames.  In this research work, a novel formulation and an associated CONDENSATION-like sampling algorithm that explicitly support counting, addition and deletion of objects are proposed.  We represent all objects in an image as an object configuration.  The a posteriori distribution of all possible configurations are explored and maintained using sampling techniques.  The dynamics of configurations allow addition and deletion of objects and handle occlusion. An efficient hierarchical algorithm is also proposed to approximate the sampling process in high dimensional space.  Promising comparative results on both synthetic and real data are demonstrated.

Experimental results

(1) Results using the original CONDENSATION algorithm
a figure, a video clip

(2) Results using the proposed algorithm
a figure, a video clip

(3) Results for tracking head+shoulder model using the proposed method
a video clip
 

Publication

[1] Hai Tao, Harpreet S. Sawhney, and Rakesh Kumar, "A sampling algorithm for detecting and tracking multiple objects," in Proc. Vision Algorithms 99, a workshop associated with International Conf. on Computer Vision, ICCV'99, 1999.