Method and apparatus for detection of a skew angle of a document image using a regression coefficient
US5563403A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 14, 1994 |
| Grant date | Oct 8, 1996 |
| Priority date | — |
| Expiry date | Dec 14, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06V30/10
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for detecting the skew angle of a document image. Skew angle determination is performed by the steps of determining a set of sampling points from an input document image and processing X and Y coordinates of the sampling points in order to calculate a regression coefficient of the sampling points. The skew angle of the document is determined using the regression coefficient. To evaluate a calculated skew angle which corresponds to the regression coefficient, a correlation coefficient is calculated and evaluated. As coordinates of sampling points are obtained for a plurality of sets of data corresponding to different ruled lines or lines of characters, a histogram may be used to determine the most probable skew angle.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.