Dark shading correction circuit
US6072527A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 19, 1997 |
| Grant date | Jun 6, 2000 |
| Priority date | — |
| Expiry date | May 19, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N25/633
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A dark shading correction circuit, used for a television camera or a video camera, is provided for canceling a dark shading signal component contained in a video signal outputted from an image pickup device (6), thereby effecting the dark shading correction on the video signal. In synchronization with a vertical synchronizing signal, the image pickup device (6) outputs a video signal containing an optical black reference signal outputted in response to each horizontal scanning signal, while a timing signal generator (10) generates at least two timing signals for detecting the optical black reference signal in the video signal. On the other hand, detection means (7a, 7b) detect at least two optical black reference signals contained in the video signal based on the at least two timing signals. Correction signal generating means (3, 8, 9) generate and output a correction signal for correcting the video signal in synchronization with the vertical synchronizing signal, based on the detected at least two optical black reference signals, so that the dark shading signal component contained in the video signal is canceled.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.