Methods and apparatus for identifying lines in an image and using identified lines
US9692937B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 10, 2015 |
| Grant date | Jun 27, 2017 |
| Priority date | — |
| Expiry date | Feb 10, 2035 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/3873
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Methods and apparatus for: identifying perimeter lines in an image, e.g., document border lines forming a non-rectangular quadrilateral corresponding to a scanned document, determining document corner points, and correcting the input image based on determined corner points are described. Lines are identified in the input image and a line weight is generated for each identified line. The identified lines are classified into two different groups based on direction, e.g., predominately vertical or predominately horizontal. For each group at least two, and sometimes more, candidate perimeter lines are determined to be kept, based on line weight and line length, and other lines in the group are eliminated. Two best candidate perimeter lines are identified from each group, e.g., based on distance between the remaining lines in the group. Four document corner points are determined based on the remaining lines in the two groups.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.