Analysis of Light Transport based on the Separation of Direct and Indirect Components

The light transport is one of the useful representation of the optical phenomena inside a scene (Sen et al;, 2005 and Seitz et al., 2005). By using this concept, we can regard any complex scene as a simple linear system between incident light and luminance distribution. However, it is difficult to obtain enough sample under varied lighting condition, because the light source has large degrees of freedom. Therefore, in this paper, we propose a fast and efficient sampling method using characteristics of direct and indirect components. Our method can be divided to three stages: at first, we obtain geometric relationships between projector and camera using Gray code. Then repetive dot patterns are projected to acquire direct reflection component in parallel. Finally, stripe pattern in a small rectangular is projected to model the low-frequency indirect light distribution. The system enables to obtain light transport quickly, and dynamic range of indirect component is also improved. Separated representation of direct and indirect components in light transport allows further applications.