Signal level correction circuit for a video signal
US5142354A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 18, 1990 |
| Grant date | Aug 25, 1992 |
| Priority date | — |
| Expiry date | Dec 18, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/72
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A signal level correction circuit for a video signal includes a voltage control amplifier for amplifying a video signal received from a solid state image sensor with different gains for the respective chrominance signals, a first clamp circuit for setting a black level in the video signal received from the amplifier, a comparator for outputting a voltage proportional to the difference between a peak holding voltage of a capacitor in the horizontal blanking period of the video signal clamped by the first clamp circuit, and a reference voltage. An adder adds the output voltage from the comparator and the video signal from the first clamp circuit. A second clamp circuit resets the black level of the amplified video signal. A .gamma. correction circuit adjusts the .gamma. value of the video signal from the second clamp circuit. A clipping circuit clips the dynamic ranges between the white and black level of the .gamma. value corrected video signal. A third clamp circuit resets the black level of the video signal from the clipping circuit. An A/D converter converts the analog video signal into a digital signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.