According to
Technology Research News, "Researchers from Stanford University and Cornell University have put together a projector-camera system that can pull off a classic magic trick: it can read a playing card that is facing away from the camera.
"The
dual-photography system gains information from a subject by analyzing the way projected patterns of light bounce off it."
"The most practical application for the researchers' technique is in relighting movie scenes... 'Suppose you're making a new sci-fi movie and you wanted to have your hero actor in a spaceship,' said Pradeep Sen, an electrical engineering researcher at Stanford University. 'Nowadays the spaceship is likely to be a computer model rather than a big set, and convincingly putting the hero into the scene involves modifying the lighting of both he scene and the hero.'
" 'Any object inside a specific environment will assume some of the color of the environment'... The effect can be subtle, but the human eye is very good at noticing if something is missing. 'For example, when an actor is inside a volcano, the actor will get a reddish tint or glow to their skin... in a rain forest there will be a greenish tone.'
"In addition, a computer-generated character will sometimes cast shadow onto the real actor. 'This lighting is often not available at the time they filmed the actor, so they have to relight the actor afterwards on the computer,' said Sen.
" 'The matrix of light properties captured by the researchers' technique contains all the information necessary to do high-resolution relighting and has the potential to do so much more rapidly than conventional techniques,' said Sen. The researchers' current prototype works with static images, but could eventually be applied to moving pictures as well, he added."
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posted by Steve Gallagher @ 6/03/2005 10:43:00 AM
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