Method and apparatus for separation of chrominance and luminance with adaptive comb filtering in a quadrature modulated color television system
US4240105A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 20, 1979 |
| Grant date | Dec 16, 1980 |
| Priority date | — |
| Expiry date | Aug 20, 1999 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/78
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An improved method and system for separating chrominance and luminance information in a quadrature modulated color television signal and similar periodic signals is disclosed. A comb filter selectively separates chrominance and luminance components from the video signal and provides a combed chrominance output and an adaptively combed luminance output. A low frequency luminance vertical transition detector is connected to an input and detects vertical amplitude transitions occurring at adjacent horizontal scanning lines and produces a first switching signal independent of the direction of a particular transition. A second transition detector detects the simultaneous occurrence of transitions in chrominance and high frequency luminance in either direction above predetermined minimum threshold values to provide a second switching signal. A subcarrier frequency-band reject filter in the luminance path, connected to be responsive to one or both of the first and second switching signals, selects subcarrier frequency band rejected luminance in lieu of combed luminance during an internal corresponding to one or both of the switching signals. The system may further or alternatively include…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.