Look-up table based gamma and inverse gamma correction for high-resolution frame buffers
US5196924A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 22, 1991 |
| Grant date | Mar 23, 1993 |
| Priority date | — |
| Expiry date | Jul 22, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09G2320/0276
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An image display system includes an input to a source (10, 12, 14) of image pixel data wherein each pixel is expressed as an M-bit value within a non-linear range of values. A first LUT (16) is coupled to an output of the source for converting each M-bit pixel value to an N-bit value within a linear range of values. An image memory, or frame buffer (18), has an input coupled to an output of the first LUT for storing the N-bit pixel values. The system further includes a second LUT (20) coupled to an output of the frame buffer for converting N-bit pixel values output by the frame buffer to P-bit pixel values within a non-linear range of values. The converted values are subsequently applied to a display (24). In an exemplary embodiment, the first LUT stores gamma corrected pixel values and the second LUT stores inverse gamma corrected pixel values. Preferably the second LUT stores a plurality of sets of inverse gamma corrected pixel values. Also, the frame buffer stores, for each of the N-bit pixel values, a value that specifies a particular one of the plurality of sets of inverse gamma corrected pixel values for use in converting an associated one of the N-bit pixel values.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.