Authors
Paul Debevec
University of California at Berkeley
Portals
Summary
In this paper, we present a general method for using accurate measurements of scene radiance in conjunction with global illumination to realistically add new objects to light-based models. The synthetic objects may have arbitrary material properties and can be rendered with appropriate illumination in arbitrary lighting environments. Furthermore, the objects can correctly interact with the environment around them: they cast the appropriate shadows, they are properly reflected, they can reflect and focus light, and they exhibit appropriate diffuse interreflection. The method can be carried out with commonly available equipment and software.
Abstract
We present a method that uses measured scene radiance and global illumination in order to add new objects to light-based models with correct lighting. The method uses a high dynamic range image-based model of the scene, rather than synthetic light sources, to illuminate the new objects. To compute the illumination, the scene is considered as three components: the distant scene, the local scene, and the synthetic objects. The distant scene is assumed to be photometrically unaffected by the objects, obviating the need for reflectance model information. The local scene is endowed with estimated reflectance model information so that it can catch shadows and receive reflected light from the new objects. Renderings are created with a standard global illumination method by simulating the interaction of light amongst the three components. A differential rendering technique allows for good results to be obtained when only an estimate of the local scene reflectance properties is known. We apply the general method to the problem of rendering synthetic objects into real scenes. The light-based model is constructed from an approximate geometric model of the scene and by using a light probe to measure the incident illumination at the location of the synthetic objects. The global illumination solution is then composited into a photograph of the scene using the differential rendering technique. We conclude by discussing the relevance of the technique to recovering surface reflectance properties in uncontrolled lighting situations. Applications of the method include visual effects, interior design, and architectural visualization.
Contribution
- We present a general method for using accurate measurements of scene radiance in conjunction with global illumination to realistically add new objects to light-based models. The synthetic objects may have arbitrary material properties and can be rendered with appropriate illumination in arbitrary lighting environments
- The objects can correctly interact with the environment around them: they cast the appropriate shadows, they are properly reflected, they can reflect and focus light, and they exhibit appropriate diffuse interreflection
- The method can be carried out with commonly available equipment and software
Related Works
Optical Film Compositing; Global Illumination; Compositing Objects into Photography
Overview
In our method for adding synthetic objects into light-based scenes, the scene is partitioned into three components: the distantscene, the localscene, and the synthetic objects. Global illumination is used to simulate the interplay of light amongst all three components, except that light reflected back at the distant scene is ignored. As a result, BRDF information for the distant scene is unnecessary. Estimates of the geometry and material properties of the local scene are used to simulate the interaction of light between it and the synthetic objects.