The core of the proposal is to develop a computer algorithm to unscramble the light that bounces off irregular surfaces to create a holographic image of hidden objects.
"This will allow us to build a 3-D representation - a hologram - of something that is out of view," said Marc Christensen, dean of the Bobby B. Lyle School of Engineering at SMU and principal investigator for the project.
Reconstructing complex reflections
In seeking proposals for its "REVEAL" program, DARPA officials noted that conventional optical imaging systems today largely limit themselves to the measurement of light intensity, providing two-dimensional renderings of three-dimensional scenes and ignoring significant amounts of additional information that may be carried by captured light. SMU's Christensen, an expert in photonics, explains the challenge like this:
"Light bounces off the smooth surface of a mirror at the same angle at which it hits the mirror, which is what allows the human eye to "see" a recognizable image of the event - a reflection," Christensen said. "But light bouncing off the irregular surface of a wall or other non-reflective surface is scattered, which the human eye cannot image into anything intelligible.
"So the question becomes whether a computer can manipulate and process the light reflecting off a wall - unscrambling it to form a recognizable image - like light reflecting off a mirror," Christensen explained. "Can a computer interpret the light bouncing around in ways that our eyes cannot?"
In an effort to tackle the problem, the proposed research effort will extend the light transport models currently employed in the computer graphics and vision communities based on radiance propagation to simultaneously accommodate the finite speed of light and the wave nature of light. For example, light travels at different speeds through different media (air, water, glass, etc.) and light waves within the visible spectrum scatter at different rates depending on color.
SOURCES - Eurekalert, DARPA, SMU