VIRTUAL art galleries hold the promise of changing exhibits in a flash. You
could stage a Picasso exhibition one day, and a Matisse the next, simply by
sending different images to wall-mounted flat-screen displays.
But the downside is that computer images tend to look flat and lifeless.
However high the screen’s resolution, the texture of a painter’s delicate stroke
work is lost. But Shree Nayer and his team at Columbia University in New York
reckon they can bring virtual art to life. The trick is to let the lighting in
the room appear to illuminate the image that’s fed to the screen—so it
appears to occupy the same space.
Nayer shows how the idea would work with a computer image of some apples on a
flat screen in his lab. When his colleague Terry Boult waves a lamp across the
screen, its light seems to dance across the apples, creating a realistic shadow
behind it, as if the fake fruit were really there. And when the room lights go
out, the picture mysteriously darkens—even though the screen is still
switched on and the image of the apples is still being fed to it.
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So how does it work? The screen’s frame contains
a camera that monitors the light falling on it
(see Graphic).
A computer uses that information to work out
how those light rays would illuminate the objects being displayed. The software,
written by Boult at Lehigh University in Bethlehem, Pennsylvania, calculates how
the light would fall on the apples eight times every second, and updates the
display accordingly. This is quick enough to look like an immediate response
when the light in the room changes.
As well as modelling apples, Boult has programmed in other household objects,
landscapes and human faces. Given a 3D map of a painting’s surface, the system
could also be used to make a screen image look more like the original. Brush
strokes would cast tiny shadows that change as the lighting changes throughout
the day and evening, vastly enhancing realism.
The new technology is dubbed LSD—short for lighting sensitive displays.
But the light sensor does not have to be a camera— it could be a far less
obtrusive arrangement of compact photodiode detectors, or optical fibres,
distributed around the device.
Mark Sherman of Corbis, the digital photo library owned by Bill Gates, says
that the hyperrealistic screen technology sounds interesting. But he warns that
people may not find it easy to obtain the high-resolution images they’ll need to
display their favourite masterpiece on a living room wall.