Method and apparatus for calibrated digital printing using a four by four transformation matrix
US5508826A · kind A · utility
Inventors
Key dates
| Filing date | Apr 27, 1993 |
| Grant date | Apr 16, 1996 |
| Priority date | — |
| Expiry date | Apr 27, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/6033
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A Self Calibrating Color Printer. The present invention enables color printers to accurately reproduce color images despite variations in ink, paper or the printing system. The calibrated printer includes a movable optical sensor assembly which first calibrates itself by measuring an included known color gamut located within the movement range of the sensor assembly. Once calibrated, the sensor assembly measures a color print test pattern newly printed by a movable color print head of the printer. An analog-to-digital converter transforms electrical signals from the sensor assembly to sensor values in digital form, enabling a printer control processor to process the measured data, thereby producing two look-up tables stored in memory: first, a color correction look-up table which adjusts image color values to account for the ink/paper variations, and second, an error diffusion look-up table which spreads color value errors at a given pixel to its neighbors. Once the printer control processor creates these two look-up tables and, the printer is able to process image data, and control the print head via its associated print head electronics to faithfully reproduce the image onto pape…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.