There has been an increase in the use of video surveillance and monitoring in public areas to improve safety and security. Change detection and crowding/congestion density estimation are two sub-tasks in a subway moni...
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ISBN:
(纸本)0769512720
There has been an increase in the use of video surveillance and monitoring in public areas to improve safety and security. Change detection and crowding/congestion density estimation are two sub-tasks in a subway monitoring system. We propose a method that decomposes this problem into two steps. The first step consists of a change detection algorithm that distinguishes the background from the foreground. This is done using a discontinuity preserving MRF-based approach where the information from different sources (background subtraction, intensity modeling) is combined with spatial constraints to provide a smooth motion detection map. Then, the obtained change detection map is combined with a geometry module that performs a soft auto-calibration to estimate a measure of congestion of the observed area (platform). Extensive experimental results in a metro station of a metropolitan city demonstrates the performance and the potential of our method.
As computervision systems are increasingly developed and tested in the real-world, there is a significant need to formalize the process of system design and analysis so that engineers can rapidly design, test, and de...
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ISBN:
(纸本)0769512720
As computervision systems are increasingly developed and tested in the real-world, there is a significant need to formalize the process of system design and analysis so that engineers can rapidly design, test, and deploy vision systems for real-world applications. Our objective in this paper is to analyze the system design, analysis, and refinement cycle through a case study involving the systematic engineering of a dual-camera video surveillance system for people detection and zooming. We illustrate how an existing system designed and analyzed by following rigorous systematic engineering principles can be extended to relax the system operating conditions with minimal re-design and analysis efforts. The key conclusion is that by choosing appropriate modules and suitable statistical representations, we are able to re-use existing system design and performance analysis results.
This paper demonstrates gait recognition using only the trajectories of lower body joint angles projected into the walking plane. For this work, we begin with the position of 3D markers as projected into the sagittal ...
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ISBN:
(纸本)0769512720
This paper demonstrates gait recognition using only the trajectories of lower body joint angles projected into the walking plane. For this work, we begin with the position of 3D markers as projected into the sagittal or walking plane. We show a simple method for estimating the planar offsets between the markers and the underlying skeleton and joints;given these offsets we compute the joint angle trajectories. To compensate for systematic temporal variations from one instance to the next-predominantly distance and speed of walk-we fix the number of footsteps and time-normalize the trajectories by a variance compensated time warping. We perform recognition on two walking databases of 18 people (over 150 walk instances) using simple nearest neighbor algorithm with Euclidean distance as a measurement criteria. We also use the expected confusion metric as a means to estimate how well joint-angle signals will perform in a larger population.
Deformable models are central to non-rigid motion analysis, shape matching and non-rigid medical image registration. Spline-based deformations are a very popular class of parameterizations of deformable models and hav...
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ISBN:
(纸本)0769512720
Deformable models are central to non-rigid motion analysis, shape matching and non-rigid medical image registration. Spline-based deformations are a very popular class of parameterizations of deformable models and have been heavily used in multiple domains. In a somewhat separate sub-field, weighted graphs are a frequently used object parameterization. Graph matching using weighted graph object parameterizations finds application in a spectrum ranging from rigid pose estimation to deformable object recognition. Here, we demonstrate a hitherto unsuspected relation,ship between spline-based deformable models and weighted graphs. It turns out that spline parameterizations in the kernel representation can be used to construct equivalent weighted graphs. With this connection established, we envision a cross-fertilization between these two seemingly disparate sub-fields of computervision.
TV conference systems have been widely used recently. A participant of each site proceeds with a TV conference using video image on a screen and voice of a partner site. In this case, a fixed video camera shoots a sce...
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ISBN:
(纸本)0769512720
TV conference systems have been widely used recently. A participant of each site proceeds with a TV conference using video image on a screen and voice of a partner site. In this case, a fixed video camera shoots a scene of a site in general. The video image taken by a fixed camera, however, is lacking in changes. Also the fixed camera does not take shots efficiency that the participants of a partner site pay attention. As one of the candidates to avoid these defects, there is a method that the computer-controlled cameras shoots the scene. In this paper, we propose an algorithm of shooting the best shot by computer-controlled cameras. The shooting algorithm is mainly decided by estimating an area of the image with high degree of attention, which is given by not only visual information but also auditory information. By using an experimental system, we confirm the effectiveness of our approach by examining a questionnaire from the participants of TV conferences.
Three different statistical models of colour data for use in segmentation or tracking algorithms are proposed. Results of a performance comparison of a tracking algorithm, applied to two separate applications, using e...
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ISBN:
(纸本)0780342364
Three different statistical models of colour data for use in segmentation or tracking algorithms are proposed. Results of a performance comparison of a tracking algorithm, applied to two separate applications, using each of the three different types of underlying model of the data are presented. From these a comparison of the performance of the statistical colour models themselves is obtained.
We present two new algorithms for multimodal, dense matching of two images using a variational approach. These algorithms complete and generalise our previous work by treating the case of semi-local energy functionals...
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ISBN:
(纸本)0769512720
We present two new algorithms for multimodal, dense matching of two images using a variational approach. These algorithms complete and generalise our previous work by treating the case of semi-local energy functionals. In brief they are derived from the maximization of two statistical criteria (mutual information and correlation ratio) estimated from corresponding regions around each pixel (or voxel in the 3D case). As a second contribution, we present a result of existence and uniqueness of the solution of the abstract evolution problems associated to these algorithms, as well as those of the corresponding global ones (the proofs could not be reproduced here but can be found in [10]). This is important since it shows the well-posedness of the problems to solve. We finish by showing some applications of our methods to one synthetic and four real examples.
We propose a new method for view synthesis from real images using stereo vision. The method does not explicitly model scene geometry, and enables fast and exact generation of synthetic views. We also reevaluate the re...
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ISBN:
(纸本)0818672587
We propose a new method for view synthesis from real images using stereo vision. The method does not explicitly model scene geometry, and enables fast and exact generation of synthetic views. We also reevaluate the requirements on stereo algorithms for the application of view synthesis and discuss ways of dealing with partially occluded regions of unknown depth and with completely occluded regions of unknown texture. Our experiments demonstrate that it is possible to efficiently synthesize realistic new views even from inaccurate and incomplete depth information.
We present a new, efficient stereo algorithm addressing robust disparity estimation in the presence of occlusions. The algorithm is an adaptive, multi-window scheme using left-right consistency to compute disparity an...
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ISBN:
(纸本)0780342364
We present a new, efficient stereo algorithm addressing robust disparity estimation in the presence of occlusions. The algorithm is an adaptive, multi-window scheme using left-right consistency to compute disparity and its associated uncertainty. We demonstrate and discuss performances with both synthetic and real stereo pairs, and show how our results improve an those of closely related techniques for both robustness and efficiency.
A local parallel method is described for computing the stochastic completion field introduced in an earlier report. The local parallel method can be interpreted as a stable finite difference scheme for solving the und...
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ISBN:
(纸本)0818672587
A local parallel method is described for computing the stochastic completion field introduced in an earlier report. The local parallel method can be interpreted as a stable finite difference scheme for solving the underlying Fokker-Planck equation identified by Mumford. The new method is more plausible as a neural model since (1) unlike the previous method, it can be computed in a sparse, locally connected network;and (2) the network dynamics are consistent with psycophysical measurements of the time course of illusory contour formation.
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