Rotation of images for optical character recognition
US5235651A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 6, 1991 |
| Grant date | Aug 10, 1993 |
| Priority date | — |
| Expiry date | Aug 6, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06V30/10
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for properly orienting an text in order to perform optical character recognition (OCR). The text is digitized and placed into an image. The image is subsampled to determine an initial "guess" about the orientation of the image. If there are are specified number of sets of lines between lines having no black-to-white or white-to-black transitions, then the image is assumed to be oriented correctly. Otherwise, the image is assumed to be perpendicular to the line-of-sight of the OCR engine and the image is rotated 90 degrees counterclockwise in a preferred embodiment. A combination of rotations and trial OCR scans for the image is performed until the best results for the trial OCR is obtained or the maximum number of iterations is exceeded. Then, the remainder of OCR is performed on the image.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.