Graphic data processing apparatus for producing a tone for an edge pixel and reducing aliasing effects
US5386509A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 9, 1993 |
| Grant date | Jan 31, 1995 |
| Priority date | — |
| Expiry date | Nov 9, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K15/128
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A tone determining apparatus for determining tones of edge pixels of vector data, is especially suitable for use within an image forming apparatus of the type writing an image on a photoconductive drum by controlling a scanning beam by pulse width modulation (PWM). The tone determining apparatus involves dividing the edge pixels of the vector data, and then transforming the area of a trailing portion into a tone using a greater contribution ratio than a contribution ratio used when transforming the area of a leading portion, whenever the edge pixel is divided in a main scanning direction. The tone determining apparatus thus eliminates fine dots otherwise appearing at the leading portion, thus providing smoother edges.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.