Image processing method using reference values to determine exposure state
US5926562A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 21, 1996 |
| Grant date | Jul 20, 1999 |
| Priority date | — |
| Expiry date | Jun 21, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/69
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A film image, which is taken into the developed photographic film, is picked up, and a reference maximum value and a reference minimum value of an image signal are determined by the image signal which is obtained when the image is picked up. The reference maximum value and the reference minimum value are used in the signal processing for adjusting the tone of the image, etc. Moreover, the exposure state of the film image is determined based on at least one of the reference maximum value, the reference minimum value, and the average value. If the exposure state is determined to be underexposured, the gamma in the gamma correction is smaller than the gamma during the standard exposure, so that the middle tone can be prevented from being dark. On the other hand, if the exposure state is determined to be overexposured, the gamma in the gamma correction is larger than the gamma during the standard exposure, so that the middle tone can be prevented from being too bright. If the color image is a color failure scene, at least one of the reference maximum value and the reference minimum value is corrected so as to realize the satisfactory color reproduction.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.