Detecting skew angle in a scanned image
US7200285B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 17, 2004 |
| Grant date | Apr 3, 2007 |
| Priority date | — |
| Expiry date | Jun 18, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/3878
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Detecting skew and determining skew angle using the front of a document by determining background-to-document transitions. Incoming scanlines are interval sampled in the fast scan direction every nth pixel. The samples are collected and organized into a two dimension array comprised of scanline based rows and interval based columns. The collected and organized samples are analyzed by intervals to determine a scanline (row) where a specified sampling condition exceeds predetermined threshold. The corresponding row-interval point forms a background-to-medium transition point of the edge of a document. When two or more background-to-medium transition points are found from different intervals the skew angle can be determined using linear regression.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.