Method and apparatus for processing a document by segmentation into text and image areas
US5883973A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 20, 1996 |
| Grant date | Mar 16, 1999 |
| Priority date | — |
| Expiry date | Feb 20, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T2207/30176
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A multi-stage, preprocessing technique increases the quality of a monochrome or colored mixed-mode document printed on a binary-type printer. The document is preferably apportioned into a plurality of small tiles, each of which provides information to the inventive technique for eventually defining the modes as either text or images. The multi-stage technique comprises a first stage for normalizing a non-ideal histogram of the mixed-mode document to a histogram having an ideal distribution of selected pixel values. A second stage classifies each tile as either text, image or background, while a third stage collates groups of tiles in both vertical and horizontal directions to remove variances in the document. Those portions of the document classified as images are then halftone processed, while the text areas are threshold processed to thereby significantly improve the reproduction quality of the printed document.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.