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Pixel non-uniformity correction system

  • US 4,602,291 A
  • Filed: 05/09/1984
  • Issued: 07/22/1986
  • Est. Priority Date: 05/09/1984
  • Status: Expired due to Term
First Claim
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1. A pixel non-uniformity correction system for use in an imager (10) wherein said system operates in three separate modes, the improvement comprising:

  • offset memory means (14) coupled to said imager for storing the dark current signal from said imager in a first mode when no light is directed to said imager,arithmetic unit means (18) coupled to said imager and said offset memory means for storing the signal from said imager in a second mode when a light of uniform, predetermined level is directed to said imager, said arithmetic unit means also subtracting the dark current signal received from said offset memory means from the signal generated upon application of said uniform light thereby generating a difference signal,gain memory means (28) coupled to said arithmetic unit means for receiving and storing said difference signal, said gain memory means also coupled back to said arithmetic unit means for presenting said difference signal to said arithmetic unit means when the system is placed in a third, operating mode,first switch means (SW2) for switching the output from said arithmetic unit means from said gain memory means to the system output such that said arithmetic unit means now compensates actual data signal from said imager upon data modulated light directed thereto for non-uniformities in each photosite of said imagers, andsecond switch means (SW1) for coupling said imager to the offset memory means in the first mode and to the arithmetic unit means in the second and third modes.

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