Method and apparatus for preparing a perspective view of an approximately spherical surface portion
US6476813B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Nov 30, 1999 |
| Grant date | Nov 5, 2002 |
| Priority date | — |
| Expiry date | Nov 30, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T15/20
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A computer system (10) can prepare and present on a display (22) a two-dimensional image that includes a perspective view, from a selected eyepoint (71, 152), of an object (23) which is a three-dimensional object of an approximately spherical shape, such as the earth. The system maintains image information for the object at each of several different resolution levels, portions of which are selected and mapped into the perspective view for respective portions of the surface of the object. In order to determine what resolution level to use for a given section of the surface of the object, the system relies on a combination of a logarithm of the square of a distance from the eyepoint to a point on the surface section, and a logarithm of the square of the degree of tilt of the surface section in relation to the eyepoint. In order to determine how far to conceptually tessellate or subdivide the surface of the object, the system relies on the logarithm of the square of the distance from the eyepoint to the point on the surface section.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.