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GRASP Student Seminar Series: Fall 2005
October 5, 5:00 PM, 307 Levine Hall
Rodrigo
Carceroni
"Recovering Photometric Properties of Multiple Strongly-Reflective,
Partially-Transparent Surfaces from a Single Image."
Abstract: I will introduce a method to recover photometric parameters of a set of 3D surfaces from a single image with significant global-illumination effects such as inter-reflections and transparencies. Since this problem is ambiguous for arbitrary unknown scenes, our formulation assumes that the scene consists of a small set of photometrically homogeneous surfaces with known 3D shapes, illuminated by known light sources.
We show that under these conditions, the system of non-linear equations that defines how the image is formed may be factorized into a vector composed only of products of some photometric parameters, and a matrix, whose elements depend non-linearly on both the known illumination, the known 3D shapes and the remaining photometric parameters. This factorization leads to an efficient optimization-based algorithm to compute all unknown photometric parameters from a single input image. Experiments with real data show that this algorithm is more stable and efficient than simpler alternatives.
Biography: Rodrigo Carceroni is a
Post-Doctoral Researcher at the the CIS Dept, U. Pennsylvania and an
Assistant Professor at Universidade Federal de Minas Gerais (UFMG),
Brazil. He received BS and MS degrees from UFMG in 1993 and 1995, and
MS and PhD degrees from the University of Rochester in 1997 and 2001,
respectively. He was appointed for his current position at UFMG in 2002.
After he got tenure (2005), he took a sabatical leave from UFMG to work
with Prof. Kostas Daniilidis at U. Pennsylvania. His current research
interests include: multi-view 3D reconstruction, photometry and motion
analysis.
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