We describe a system that automatically tracks moving objects in a scene and subjectively characterizes the object trajectories for storage and retrieval. A multi-target color-histogram particle filter combined with besthypothesis data association is the foundation of our trajectory acquisition algorithm. To improve computational performance, we use quasi-Monte-Carlo methods to reduce the number of particles required by each filter. The tracking system operates in real-time to produce a stream of XML documents that contain the object trajectories. To characterize trajectories subjectively, we form a set of shape templates that describes basic maneuvers (e.g., gentle turn right, hard turn left, straight line). Procrustes shape analysis provides a scaleand rotation-invariant mechanism to identify occurrences of these maneuvers within a trajectory. To add spatial information to our trajectory representation, we partition the two-dimensional space under surveillance into a set of mutually exclusive regions. A temporal sequence of region-to-region transitions gives a spatial representation of the trajectory. The shape and position descriptions combine to form a compact, high-level representation of a trajectory. We provide similarity measures for the shape, position, and combined shape and position representations.
We present a system for the broadcast of hockey games over the internet. The system allows users to experience the hockey game while it is in progress. Our system uses generic content description servers that acquire information from an external source, process it, and serve the processed data to client systems. Dynamic configuration of the servers allows us to use them in a variety of roles. For example, video information servers, like an MPEG-7 camera, produce
XML documents that describe the motion of objects in the scene in addition to unprocessed video. Unlike an MPEG-7 camera, our video information servers interact with client systems, and can change their behavior through dynamic configuration. In an alternate configuration, a content description server acts as a game server in our hockey broadcast system. The game server forms an environment model that encapsulates the state of the hockey game and serves
data from the model to clients. We developed and tested our system using a 1/32-scale model of a hockey rink. Early results using data acquired at a real rink indicate that the system performs as expected.
As processor speeds increase and the cost of digital video technology falls, the use of video is expanding in a plethora of applications including video surveillance, human computer interaction, tele-instruction, and enhanced sports broadcasts. However, a major problem that now faces developers of video systems is the requirement to build the low-level video processing from the ground up for each application. This paper describes a camera system that acts not merely as a provider of pixels, but as a video information server. A video application interacts with the camera server using the Camera Markup Language (CaML, pronounced camel) proposed here. CaML is an XML-based (Extensible Markup Language) data format for exchanging video information with a server. It provides a layer of abstraction between the application and the pixels to simplify the development process and is well-suited to exchanging data over a network. Using a camera as a server on a network makes it a simple matter for a single application to use multiple cameras. Local- and wide-area networks (LANs and WANs) replace the need for conventional methods for routing video signals.
Conference Committee Involvement (4)
Internet Imaging VII
18 January 2006 | San Jose, California, United States
Internet Imaging VI
19 January 2005 | San Jose, California, United States
Internet Imaging V
19 January 2004 | San Jose, California, United States
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