Automatic dark level zeroing for an analog video signal
US5471244A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 31, 1994 |
| Grant date | Nov 28, 1995 |
| Priority date | — |
| Expiry date | May 31, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N25/71
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An automatic dark level zeroing circuit removes a dark level DC bias from an analog video signal generated by a charge-coupled device (CCD) camera, The automatic dark level zeroing circuit is DC-coupled to the CCD camera such that there is no loss of low frequency information in the analog video signal, The automatic dark level zeroing circuit forms an adaptive feedback loop that removes the dark level DC bias from the analog video signal by using a sampled value of the analog video signal that represents an internally masked pixel to produce a zero correction signal that is then combined with the analog video signal to remove the dark level DC bias without removing any useful video information or otherwise altering the information content of the analog video signal,
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.