Higher precision look-up table from lower precision look-up table for improved tonal adjustment
US5719965A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 13, 1994 |
| Grant date | Feb 17, 1998 |
| Priority date | — |
| Expiry date | Dec 13, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/407
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An image capture system comprising a scanner having a 10-bit analog-to-digital converter. The scanner operates within an environment that includes a host computer that is configured to accept 8-bit data. The contrast enhancement of the scanner is improved by applying an improved tonal adjustment on a scanned image. The host computer connected to the scanner provides an 256-value to 256-value look-up table (i.e., the 8-bit tone map) to the scanner. The scanner generates an interpolated 1024-level to 256-level look-up table (i.e., a 10-bit tone map) from the 256-level to 256-level look-up table. The 1024-value to 256-value look-up table is generated by using linear interpolation and extrapolation. The scanner can thus provide better contrast enhancements without having to modify the software running on the host computer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.