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This system has come out of our work in VSAR - a collaborative project part funded by the Technology Strategy Board in which we are working with other UK partners to investigate approaches to merging 3D models with live images and other data to help people interpret events across a large area.Ìý Our interest is in portraying events such as Wimbledon, whilst other partners are looking at applications in fields like security and surveillance.Ìý We worked with one of the project partners, , to produce the interactive visualisation system.Ìý We also worked closely with (who create high-end 3D models, for example as used for virtual flights around the Beijing Olympic venues) who created the model of Wimbledon and rendered the virtual flights.Ìý

The system uses two PCs and a video router, set up in the back of one of the outside broadcast trucks at Wimbledon. When the operator selects the courts to fly between, the video router passes the camera feeds from the courts to video capture cards on the PCs.Ìý One PC runs software to track the motion of each camera by reference to the court lines (based on the technology we developed for the award-winning Piero system), so the system knows its current pan, tilt and field-of-view.Ìý The other PC plays the appropriate pre-rendered animation from a RAID disk array, and uses a graphics card to project the video from the cameras onto the relevant courts, taking account of the current position and orientation of both the live cameras and the 'virtual' camera used when rendering the animation.Ìý A carefully-crafted arrangement of soft-edge masks ensures that the live video 'illuminates' the court area without turning the crowd into a mixture of real and virtual people.Ìý As the video is only a 2D representation of the scene, it cannot produce an accurate rendition if viewed from a location a long way away from the real camera position, but by carefully choosing the animation paths it is possible to produce a surprisingly realistic result.

We hope to further develop the system, for example to allow interactive use on-line, and will work with ´óÏó´«Ã½ Sport and Crystal CG to explore other events that it could be used for, possibly including the 2012 Olympics.

I'd like to thank my colleagues who worked on the system, particularly Bruce Weir, as well as our partners at CAST, and our collaborators at Crystal CG, for all the effort they have put into getting the trial on air.