Patent ID: 6549239
Filing Date: 2003-04-15
Classification: H04N

Abstract:
A system for video imaging of an object having an illumination source with an adjustable intensity, comprising:a progressive-scan charge-coupled device (PSCCD) sensor having an exposure time, an exposure time signal input, an optical input and an analog electrical signal output corresponding to an optical image at said optical input; a lens assembly positioned relative to said PSCCD sensor to image said object on said optical input; an A/D converter for converting the analog electrical signal into a digital data set corresponding to a video image of the object, said A/D converter comprising a high reference input and a low reference input which are adjustable to adjust the contrast, and further comprising a first D/A converter connected from said processing means to said high reference input of said A/D converter to adjust the high reference level and a second D/A converter connected from said processing means to said low reference input of said A/D converter to adjust the low reference level; a timing circuit having a time control signal output coupled to the PSCCD sensor exposure time input to control an exposure time during which the PSCCD sensor senses said optical input, said exposure time signal corresponding to an effective shutter speed for the video system; and a processing means operatively connected to said illumination source, having an adjustable brightness and duration, and said timing circuit for automatically adjusting the intensity of the illumination source, including the brightness and duration thereof, and for controlling the timing circuit to adjust the effective shutter speed in response to changing lighting conditions, including processing means for selecting a digital video data set, processing means for determining a histogram and a cumulative distribution function of brightness levels of a selected digital video data set, and means for determining a change in lighting conditions.