My area of interest is computer graphics specifically on realistic image synthesis in particular global illumination, and viewpoint interpolation for videos.

Research Objective

The objective of my PhD is to acquire material properties of objects captured by (multiview) video. This includes dynamic scenes and changing illumination.

The geometric information and materials acquired can then later be changed together with the illumination.

Subsurface Scattering

Subsurface scattering

All non-metallic materials are translucent to some degree. This means that light scatters inside the material before being either absorbed or leaving the material at a different location. This phenomenon is called subsurface scattering. As an example, a translucent marble dragon is shown here. Note the soft and smooth appearance as well as the light diffusing through the marble.

True subsurface scattering cannot be simulated using the ubiquitous BRDF (Bidirectional Reflectance Distribution Function). Instead it requires a full simulation of the BSSRDF (Bidirectional Scattering Surface Reflectance Distribution Function). Traditional methods such as monte-carlo integration are quite good at simulating subsurface scattering, but it becomes costly for highly scattering materials such as milk and skin. For these materials it is better to use a diffusion approximation. The diffusion approximation is much faster while remaining fairly accurate. We presented a multigrid based method capable of rendering heterogeneous, arbitrarily shaped objects within several minutes. This is collaborative work with Tom Mertens.

Video Viewpoint Interpolation

Free viewpoint video

This project attempts to expand the user experience by allowing him to change the viewpoint of the video while watching it. This is accomplishing by first capturing the scene using many cameras, and then interpolating between the captured viewpoints. This work focuses on many areas including: stereo vision, matting, optical flow, compression and rendering.

The image is courtesy of Zitnick et al.

Photorealistic Image Synthesis

Global Illumination

The production (rendering) of realistic images in particular requires a precise treatment of lighting effects. This can be achieved by simulating the underlying physical phenomena of light emission, propagation, and reflection.

last update November 6, 2006