Logarithmic color matrix for a digital television receiver
US4544945A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 7, 1983 |
| Grant date | Oct 1, 1985 |
| Priority date | — |
| Expiry date | Jun 7, 2003 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/67
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In a digital television receiver, a signal processing stage generates color mixture digital signals representing color picture information as components in a first color mixture coordinate system such as the I-Q system. The I and Q digital signals are applied to a read only memory look-up table in which memory locations are stored the logarithmic values of the signals in order to convert the signals into digital words represented in logarithmic form. A microprocessor or other digital circuit generates or retrieves digital coefficients in logarithmic form that enable the I and Q digital signals to be transformed into second color mixture digital signals representing the color picture information as components in a second color mixture coordinate system such as the R-Y, B-Y, color difference coordinate system. The I and Q digital signals in logarithmic form are applied to a first input of an adder. A digital store stores the coefficients, and a multiplexer coupled to the digital store supplies to a second input of the adder a sequence of coefficients in the same order corresponding to the sequence of I and Q digital signals being applied to the first input of the adder. At the output…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.