Method of obtaining optimum threshold values
US5097520A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 27, 1989 |
| Grant date | Mar 17, 1992 |
| Priority date | — |
| Expiry date | Dec 27, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06V30/10
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A binarization method obtains an optimum threshold value for binarization which is used when converting a multi-level image data which describes an input image into a black-and-white bi-level image data. The binarization method includes the steps of counting a first number of black picture elements by varying a threshold value from a darkest tone level to a lightest tone level, counting a second number of picture elements having a tone level other than the lightest tone level, obtaining a percentage of the first number with respect to the second number for each of the varied threshold values so as to normalize a density of the input image, and determining the optimum threshold value for binarization based on the percentage which is obtained for each of the varied threshold values.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.