Tonescales for geographically localized digital rendition of people
US7372597B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 27, 2004 |
| Grant date | May 13, 2008 |
| Priority date | — |
| Expiry date | Nov 24, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/6027
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In a method and system for processing a photographic image having lightness values, L*, representing one of the colorimetric values of an original scene, the photographic image is transformed. The transformed image has a gamma as a function of CIE 1976 L*, which includes a dark region having a rising slope, a light region having a falling slope, and a plateau region having a slope constantly within 5 percent of a maximum value in said plateau region. The rising slope is at least twice as large as the absolute value of the falling slope. The plateau region is between 10 L* and 30 L* wide. Gamma is a derivative of visually perceived reproduced CIE 1976 L* versus scene CIE 1976 L*. Gamma has a maximum slope between 1.5 and 2.0.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.