Computer Vision Talks at Columbia University

Synthesizing bidirectional texture functions for real-world surfaces

Harry Shum

Microsoft Research Asia

Monday, March/4, 2 PM

Interschool Lab, 7th Floor CEPSR, Schapiro 

Host: Prof. Shree Nayar 

Abstract 

In this paper, we present a novel approach to synthetically generating bidirectional texture functions (BTFs) of real-world surfaces. Unlike a conventional two-dimensional texture, a BTF is a six-dimensional function that describes the appearance of texture as a function of illumination and viewing directions. The BTF captures the appearance change caused by visible small-scale geometric details on surfaces. From a sparse set of images under different viewing/lighting settings, our approach generates BTFs in three steps. First, it recovers approximate 3D geometry of surface details using a shape-from-shading method. Then, it generates a novel version of the geometric details that has the same statistical properties as the sample surface with a non-parametric sampling method. Finally, it employs an appearance preserving procedure to synthesize novel images for the recovered or generated geometric details under various viewing/lighting settings, which then define a BTF. Our experimental results demonstrate the effectiveness of our approach.
Time permitting, I will also show some latest research results on rendering BTF.
*(Siggraph'2001, Los Angeles)

Bio
Harry Shum received his Ph.D. in robotics from the School of Computer Science, Carnegie Mellon University in 1996. He worked as a researcher for three years in the vision technology group at Microsoft Research Redmond. In 1999, he moved to Microsoft Research Asia where he is currently a senior researcher and the assistant managing director. His research interests include computer vision, computer graphics, human computer interaction, pattern recognition, statistical learning and robotics.