Shading correction device
US4633314A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 14, 1983 |
| Grant date | Dec 30, 1986 |
| Priority date | — |
| Expiry date | Jul 14, 2003 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N25/61
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A shading correction device has a variable attenuator which is provided in the transmission line of the picture signal after photoelectric conversion by the original reader. For example, at the time of reading all white surface of the original at the beginning of the original scan the information level of each bit of the picture signal, i.e., the level of each picture element, is sequentially attenuated by the variable attenuator. In order to make the level of each picture element uniform, a data on how much attenuation is required, is generated for each picture element and loaded in a memory. The variable attenuator is adapted to be driven and controlled based on the data loaded in the memory at the time of reading the original in the subsequent scan.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.