Importance

Loading Importance Indicators...

Abstract

A video image enhancer is disclosed for use in surveillance at low light levels to enhance dark and/or low contrast segments of a composite video signal of a surveyed scene by subjecting the dark and/or low contrast segments thereof to high gain and bright and/or high contrast segments to low gain. The video image enhancer includes an input designed to receive the composite video signal, a device provided with a dc restorer circuit and a variable potentiometer to yield an adjustable-bias dc clamp of the composite video signal, a second variable potentiometer for adjusting the high-gain slope of the device, a diode clamp connected to the device's output, and a pair of drivers coupled to the device's output to provide a low impedance output video signal with its dark and/or low contrast segments enhanced. Preferably, the device is a non-inverting operational amplifier. Preferably, the pair of drivers comprise a pair of NPN transistors connected in an emitter-base configuration.

Loading the Abstract Image...

First Claim