Methods and apparatus for auto image binarization
US8351699B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 18, 2009 |
| Grant date | Jan 8, 2013 |
| Priority date | — |
| Expiry date | May 10, 2031 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06V10/28
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A threshold determination method is selected from among a plurality of alternative global thresholding determination methods and, optionally, a local thresholding determination method based on characteristics of a histogram of grayscales values representing an image. When it is determined to use a global thresholding method, a single global binarization threshold value is determined using the selected global thresholding method. Various alternative global binarization threshold values include a predetermined constant, an average value of the two grayscale values, an Otsu method based threshold value, a Newton method based threshold value, and an Otsu method based threshold value based on a truncated version of the histogram. When it is determined to use local thresholding, a plurality of local binarization threshold values are determined corresponding to different non-overlapping blocks of the image. The determined binarization threshold(s) are applied to the gray scale pixel values to obtain a set of binary pixel values.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.