System for deriving radiation images
US4928250A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 2, 1986 |
| Grant date | May 22, 1990 |
| Priority date | — |
| Expiry date | Jul 2, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T15/55
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
In an algorithm for deriving radiation images, where view independent radiation calculations are precomputed so that they do not need to be repeated for every view of the same environment. To find the form factors for radiosity techniques, a hemi-cube is constructed around the surface with grid cells defined for all faces on the hemi-cube. All other surfaces in the environment are projected onto the hemi-cube to facilitate the form factor calculations. A novel ray-tracing technique is disclosed where a light buffer in the form of a cube is constructed around each radiation source and grid cells are defined on the faces of the cube. Surfaces in the environment are projected onto the cube and the depths from the source are stored for each grid cell to facilitate shadow testing. Light reflected off of the viewed surface from another surface may be modeled by determining mirror positions of the viewer and the image plane. Instead of storing the depths of surfaces from the viewer or the radiation source, the identity of the polygons in the environment are stored instead to speed up the calculations. Scan conversion hardware is used to accelerate each of these operations. In a graphics p…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.