Rendering process and method for digital map illumination intensity shading
US6288721A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 7, 1999 |
| Grant date | Sep 11, 2001 |
| Priority date | — |
| Expiry date | Jul 7, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T15/50
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A "Rendering Process and Method for Digital Map Illumination Intensity Shading" is disclosed that assigns an illumination intensity to pixels in a video display imaging a mapped terrain. The process comprises the steps of: providing a rectangular grid array of altitude values covering an area to be shaded. Each altitude value has a map position characterized by a coordinate location referenced to a first and second coordinate axes crossing orthogonally at an origin. Each coordinate location has a first and second value. Each first and second value characterizes the distance of the respective coordinate location from the origin. The map area is divided into an array of contiguous triangles. Each triangle area has a perimeter bounded by three straight line segments passing between three coordinate locations. The video display has pixel areas that corresponding to each respective triangle area. A normal vector is calculated for each triangle area. An illumination vector referenced to the coordinate axes is provided that characterizes the direction and intensity I of a light source that illuminates all of the triangle areas. The process calculates a relative angle between the normal ve…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.