Apparatus and method for estimating reflected radiance under complex distant illumination
US7091973B1 · kind B1 · utility
Inventor
Key dates
| Filing date | Jun 20, 2003 |
| Grant date | Aug 15, 2006 |
| Priority date | — |
| Expiry date | Jun 16, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T15/50
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An apparatus and method for estimating reflected radiance under complex distant illumination are described. In one embodiment, an importance sampling estimator is used with a novel piecewise constant importance function that effectively concentrates ray samples where energy is likely to be found. To properly account for the effects of a visibility term in the shading calculation, in one embodiment, a shadow cache is provided which caches information indicating ray directions that are occluded or unoccluded from a point in space. Accordingly, by concentrating hemispheric samples where the light source is likely to be strongest, a reflected radiance integral is efficiently computed and estimated in a real-world lighting situation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.