Method and system for providing automatic gain control in an imaging device using signal combination and threshold comparison

A method for providing automatic gain control (AGC) in an image capture device comprises: accumulating a signal in response to light at each active pixel 114 in an image sensor during an exposure period; producing a comparison signal (504, Figure 5) in response to a combined signal of the accumulate...

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Bibliographic Details
Main Author BRIAN J MISEK
Format Patent
LanguageEnglish
Published 16.04.2008
Subjects
ELECTRIC COMMUNICATION TECHNIQUE
ELECTRICITY
PICTORIAL COMMUNICATION, e.g. TELEVISION
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Summary:A method for providing automatic gain control (AGC) in an image capture device comprises: accumulating a signal in response to light at each active pixel 114 in an image sensor during an exposure period; producing a comparison signal (504, Figure 5) in response to a combined signal of the accumulated signal at each active pixel; and comparing the (summed) comparison signal with a threshold signal to derive a shutter value for image capture, including measuring the time duration for the comparison signal to become equal to the threshold (506, Figure 5). Also independently claimed is a system for providing such automatic gain control having an integration circuit 104, threshold or reference signal comparator 106, and counter 108 for measuring the time for the comparison signal to equal the threshold signal.
Bibliography:Application Number: GB20070019906