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Method for reducing fixed pattern noise in solid state imaging devices

  • US 5,953,060 A
  • Filed: 09/30/1998
  • Issued: 09/14/1999
  • Est. Priority Date: 10/31/1995
  • Status: Expired due to Term
First Claim
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1. A method for reducing noise in a solid state imaging device having a group of active pixels, said method comprising the steps of:

  • reading out the signal of a pixel in a first state while forcing the output voltage of an amplifying element that is connected to said pixel to a predetermined output voltage level, thereby defining a corresponding voltage level on a control terminal of said amplifying element and storing said corresponding voltage level or a measure thereof on a memory element that is connected to said pixel and thereby defining, a first voltage at the output of said amplifying element;

    subtracting said first voltage at the output of said amplifying element from a second voltage at the output of said amplifying element, said second voltage being defined by the output signal of the same pixel in a second state and said second voltage including the voltage level stored on said memory element, whereby the output voltage of the amplifying element shifts proportionally to the difference of the signal of said pixel in said first and said second state;

    transferring the subtracted signal to an output line that is common for said group; and

    repeating this operation for essentially all or part of the pixels of the imaging device.

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