Image processing method and apparatus using a truncated histogram
US6018589A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 9, 1995 |
| Grant date | Jan 25, 2000 |
| Priority date | — |
| Expiry date | May 9, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/11
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The gradation data is found from image signals for one screen, which are obtained when an image is picked up, and a histogram is made by counting all the gradation data for one screen in every gradation, with a predetermined frequency as an upper limit. Then, a reference minimum value of the image signals is calculated by detecting a point where a cumulative frequency which is counted from a small gradation of the histogram reaches a predetermined rate for total number of the gradation data, and a reference maximum value of the image signals is calculated by detecting a point where a cumulative frequency which is counted from a large gradation of the histogram reaches a predetermined rate. The image processing is carried out in accordance with the calculated reference minimum value and reference maximum value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.