Binary quantification of an image having multiple levels of greys
US4977605A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 27, 1988 |
| Grant date | Dec 11, 1990 |
| Priority date | — |
| Expiry date | May 27, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/403
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Method for transforming a video type image having multiple levels of greys into a binary image, method wherein each pixel is either white or black. With each pixel of the initial image there is associated a partial image centered on said pixel and comprising a plurality of pixels in at least one dimension. If the histogram of the grey levels of said partial image is considered as bimodal (D>E), a threshold (S) median with respect to said histogram is selected. If the histogram is considered as monomodal (D<e), a threshold (S) outside said histogram is selected, the position of this threshold with respect to the histogram being determined by comparison of the latter with a preset mean background value (FM). Application to telecopy, electronic storage of documents and drawings, preprocessing in order to facilitate the reading of handwritten messages or recognition of patterns in general.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.