Showing papers by "Anurag Mittal published in 2004"
27 Jun 2004
TL;DR: A new method for the modeling and subtraction of scenes that consist of static or quasi-static structures that exhibits a persistent dynamic behavior in time is proposed and extensive experiments demonstrate the utility and performance of the proposed approach.
Abstract: Background modeling is an important component of many vision systems. Existing work in the area has mostly addressed scenes that consist of static or quasi-static structures. When the scene exhibits a persistent dynamic behavior in time, such an assumption is violated and detection performance deteriorates. In this paper, we propose a new method for the modeling and subtraction of such scenes. Towards the modeling of the dynamic characteristics, optical flow is computed and utilized as a feature in a higher dimensional space. Inherent ambiguities in the computation of features are addressed by using a data-dependent bandwidth for density estimation using kernels. Extensive experiments demonstrate the utility and performance of the proposed approach.
648 citations
11 May 2004
TL;DR: In this article, visibility from static sensors in a dynamic scene with moving obstacles (people) is considered in a probabilistic sense in the context of multiple sensors, so that visibility from even one sensor might be sufficient.
Abstract: We analyze visibility from static sensors in a dynamic scene with moving obstacles (people). Such analysis is considered in a probabilistic sense in the context of multiple sensors, so that visibility from even one sensor might be sufficient. Additionally, we analyze worst-case scenarios for high-security areas where targets are non-cooperative. Such visibility analysis provides important performance characterization of multi-camera systems. Furthermore, maximization of visibility in a given region of interest yields the optimum number and placement of cameras in the scene. Our analysis has applications in surveillance – manual or automated – and can be utilized for sensor planning in places like museums, shopping malls, subway stations and parking lots. We present several example scenes – simulated and real – for which interesting camera configurations were obtained using the formal analysis developed in the paper.
81 citations
24 Oct 2004
TL;DR: A stereo rectification method suitable for automatic 3D surveillance that takes advantage of the fact that in a typical urban scene, there is ordinarily a small number of dominant planes.
Abstract: We describe a stereo rectification method suitable for automatic 3D surveillance We take advantage of the fact that in a typical urban scene, there is ordinarily a small number of dominant planes Given two views of the scene, we align a dominant plane in one view with the other Conjugate epipolar lines between the reference view and plane-aligned image become geometrically identical and can be added to the rectified image pair line by line Selecting conjugate epipolar lines to cover the whole image is simplified since they are geometrically identical In addition, the polarities of conjugate epipolar lines are automatically preserved by plane alignment, which simplifies stereo matching
11 citations