Event Location: NSH 1507
Bio: Mohit Gupta is a 4th year PhD student in the Robotics Institute advised
by Srinivasa G. Narasimhan. He received his B.Tech. in Computer Science
from the Indian Institute of Technology, New Delhi in 2003. He received
his M.S. in Computer Science from the Stony Brook University, New York
in 2005. His research interests are in physics-based computer vision and
computer graphics. Currently, he is focusing on designing active vision
systems for recovering scene properties under complex light transport.

Abstract: Most active scene recovery techniques assume that a scene point is
illuminated only directly by the illumination source. Consequently,
global illumination effects due to inter-reflections, sub-surface
scattering and volumetric scattering introduce strong biases in the
recovered scene shape. Our goal is to recover scene properties in the
presence of global illumination. To this end, we study the interplay
between global illumination and the depth cue of illumination defocus.
By expressing both these effects as low pass filters, we derive an
approximate invariant that can be used to separate them without
explicitly modeling the light transport. This is directly useful in any
scenario where limited depth-of-field devices (such as projectors) are
used to illuminate scenes with global light transport and significant
depth variations. We show two applications: (a) accurate depth recovery
in the presence of global illumination, and (b) factoring out the
effects of defocus for correct direct-global separation in large depth
scenes.