Apparatus and method for skew control of document images
US5001766A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 16, 1988 |
| Grant date | Mar 19, 1991 |
| Priority date | — |
| Expiry date | May 16, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N2201/0432
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for determining a predominant angle of orientation of an image with respect to a reference angle. A file of picture elements is generated which depicts the image with respect to the reference angle. The picture elements are projected onto a plurality of contiguous segments of imaginary lines at selected angles across the file. Each imaginary line is perpendicular to its associated direction of projection. The number of picture elements that fall into the segments for each projection are counted. An enhancement function is applied to the segment counts of each projection. The projection that generates the largest value of the enhancement function defines the angle of orientation of the image. The position of a document scanner or the document itself may be rotated to compensate for the detected skew.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.