Halftone detection and removal
US7586647B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 6, 2005 |
| Grant date | Sep 8, 2009 |
| Priority date | — |
| Expiry date | May 29, 2027 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/40075
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Methods, computer program products and apparatuses are disclosed for processing images to detect and/or remove halftone. In one aspect, a portion of an image comprising a plurality of color channels is selected for processing (210), a frequency domain representation of the selected portion is generated for each color channel (220), data relating to predetermined regions in the frequency domain representations is processed (230), and halftone present in the selected portion is detected based on a result of the processing the data (240). In another aspect, an image is arranged into a plurality of bands each comprising a predetermined number of consecutive lines of pixels, each of the plurality of bands is arranged into a plurality of tiles of pixels, one of the plurality of tiles is selected as a selected portion, data relating to the selected portion is processed and halftone present in the selected portion is detected based on a result of the processing and on a result of processing at least one other portion of the image. Halftone may be detected based on spatial characteristics or frequency characteristics within the selected portion and detected halftone may be removed from spat…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.