Graphics encoder video enhancement
US5012331A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 23, 1989 |
| Grant date | Apr 30, 1991 |
| Priority date | — |
| Expiry date | Jun 23, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/646
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A color enhancement circuit according to the present invention extracts "sine-squared" (haversine) pulses representing absolute values for the derivatives of R-Y and B-Y color difference "sine-squared" transitions; multiples by offset, sign-inverted luminance, and adds the luminance-weighted "singe-squared" pulses to the composite video as color enhancement signals which exceed the NTSC-legal chroma bandwidth but are within the NTSC-legal luminance bandwidth. The pulses augment luminance during chroma transitions, restoring luminance contributions from chrominance which are lost when chroma subcarrier packet risetimes and bandwidth are limited by NTSC broadcast requirements.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.