Shedding Light on Illumination

Wednesday, November 15, 2000 - 2:00pm - 3:00pm
Keller 3-180
Peter Belhumeur (Yale University)
In this talk we consider a number of interrelated issues in the appearance and modeling of objects over changes in illumination: 1. We show that show that for an object with Lambertian reflectance there are no discriminative functions that are invariant to illumination. 2. We develop a generative method for modeling objects under variable illumination and pose from a small number of exemplars. 3. We point out implicit ambiguities and historical missteps in determining shape from shadows and shading. 4. We develop an exhaustive phenomenological method for shape reconstruction and image-based rendering that differs from item 2 above in that it makes no assumptions about an objects shape or BRDF. 5. We present a low-dimensional, data-driven representation for BRDFs in an attempt to bridge the gap in the above-mentioned methods. Throughout the talk we present supporting results and demonstrations using large databases of objects and faces under variable illumination