the field of
by Paul Gilster
There is a place between light and
shadow that changes the way we look
at things. Ask any traveler — the Taj
Mahal at dusk is a different place than
the Taj Mahal at noon. And it was natural that this classic example of chang-
ing visual textures — a building whose marble hues
vary with the intensity of light — should have seized
the imagination of Ramesh Raskar ’02 (PhD). The
India-born computer scientist, working at UNC with
computer graphics gurus Greg Welch and Henry Fuchs,
has created what he calls “shader lamps” that use light
the way sculptors use clay, as a plastic, creative medium.
Clay, in fact, is what makes up a small white model
of the Taj Mahal that Raskar used as his palette, painting
it with the changing light from different projectors. It’s
the interplay of the digital and the physical: An object
(the model) is illuminated by computer-calibrated light.
What you see is a building that changes as the projectors control the shadings of dawn, noon and dusk. Take
that idea into the business world, and a car dealership
could model a single car in a variety of colors and finishes, while a clothing salon could offer the latest styles
and fabrics projected onto a neutral store manikin.
We’ve entered the world of “augmented reality,” a
discipline now championed by Raskar in his position as
senior research scientist for Mitsubishi Electric Research
Laboratories (MERL) in Cambridge, Mass. Augmented
reality is a step beyond “virtual” reality, in which the
user needs goggles or other kinds of equipment to
experience computer-generated effects.
“While virtual reality completely replaces your surroundings with a synthetic world, augmented reality
says my world is pretty interesting on its own,” Raskar