Pattern recognition method
US4961231A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 31, 1987 |
| Grant date | Oct 2, 1990 |
| Priority date | — |
| Expiry date | Dec 31, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06V30/10
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A pattern recognition method comprises a contour tracing step of a contour of a binary image in a predetermined direction along a predetermined type of pixels. At this time, four adjacent pixels on upper, lower, left-hand and right-hand sides of a point of interest are sequentially checked. Then, one pixel of a predetermined type out of the four adjacent pixels which is the first pixel of the predetermined type found by the check is designated as a next trace point subsequent to the point of interest. In this process, a feature of each of the traced pixels is extracted. The feature is represented by a directional code which indicates a direction of motion from the point of interest to the next trace point. The features are successively registered in a one-dimensional form. Histogram is produced for each sub-region storing a part of the one-dimensional feature sequence. A histogram for each sub-region is compared with a related reference histogram for a known character.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.