Patent · US Active

Grey value correction method for binary image data

US7933466B2 · kind B2 · utility

0Cited by

13References

16Claims

0Family size

Assignee

Heidelberger Druckmaschinen AG · DE

Inventors

Michael Hansen · Odense, DK
Jörg Olaf Von Wechgeln · Wattenbek, DE

Key dates

Filing date	Mar 24, 2004
Grant date	Apr 26, 2011
Priority date	—
Expiry date	Nov 22, 2027

Classification

Technology area (CPC H)Electricity
CPC primaryH04N5/20
WIPO fieldAudio-visual technology
WIPO sectorElectrical engineering

Abstract

A method of gray value correction for binary image data, preferably screened image data, with a local gray value by a desired correction magnitude includes filtering the image data quantized with n bits with an asymmetrical low-pass filter whose filter window is smaller than a screen cell. By a threshold value operation, corrected binary image data is obtained from the filtered image data. Optimum threshold values are selected from a threshold value table as a function of the local gray value and of the desired correction magnitude.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.