Combined dot density and dot size modulation
US7031025B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 23, 2000 |
| Grant date | Apr 18, 2006 |
| Priority date | — |
| Expiry date | Apr 12, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/4057
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A combined dot density and size modulation system uses dispersed dot halftoning in conjunction with dot size modulation to produce a halftone image in which both the density and size of the dots are modulated to control overall gray level. The dot density and size modulation system offers advantages over pure dot density modulation systems or pure dot size modulation systems because it allows an extra degree of flexibility which can be used to increase the visual quality of the halftoned pattern and/or increase the robustness of the halftoning to printer artifacts and variations. An input pixel value is used to independently produce a dot density value and a dot size value. The dot density value and dot size values may be obtained from, e.g., look up tables that have been optimized for print quality and printer stability. Dispersed dot halftoning is used to provide a halftone value for the desired pixel location using the dot density value. The dispersed dot halftoning may be, e.g., tone dependent error diffusion. The halftone value and the dot size value for the pixel location is then used to generate a modulated code, e.g., a pulse width modulated code, to the printer. The modula…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.