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March 28th, Niranjan

Relighting and Subsurface Light Transport


Image formation is a sophisticated process involving a complex interplay of angular and spatial dimensions of incident illumination and is completely determined by the scene's apparent Bidirectional Scattering Distribution Function (BSDF). Due to the high dimensionality of BSDF, inverse rendering is severely ill posed in most cases. We take a fresh look at the Light Transport Matrix (LTM) that models spatial interactions of light with the scene and provide two new array of array representations for the LTM, inspired from light field imaging. The first representation allows us to isolate the elusive subsurface scattering component of the BSDF, from a few observations of the object under spatially varying illumination patterns. Connected component analysis on the second representation lets us to learn a material specific dictionary of  subsurface light transport functions which can act as a strong prior on subsurface light transport during inverse rendering under arbitrary, uncontrollable, real-world illuminations. Finally, we will present the proposed forward model that incorporates the learnt prior.

Posted by Runwei Zhang on Thursday 23 January 2014 at 13:11