Estimating Positions and Radiances of a Small Number of Light Sources for Real-Time Image-Based Lighting

Abstract

Image-based lighting (IBL) of virtual objects has become a popular approach to blending virtual and real scenes. In IBL an omni-directional image of a scene is used as the illumination environment for rendering virtual objects. Typically, this rendering is based on global illumination techniques which are far from capable of real-time performance. In this paper we describe how to estimate the positions and radiances of a small number of point light sources, e.g., on the order of 5 to 10, which will produce virtual object appearances which are consistent with those obtained using IBL. The estimated light source parameters can be used directly in OpenGL rendering for real-time performance. We demonstrate the approach on natural scenes.