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Data digitization and display for an imaging system

  • US 10,075,658 B2
  • Filed: 05/30/2014
  • Issued: 09/11/2018
  • Est. Priority Date: 05/30/2014
  • Status: Active Grant
First Claim
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1. A method for processing data from an imaging system, comprising;

  • sampling a signal from an optical detector with a first sample and hold, S/H, for a first sample time ts/h1 and with a second S/H for a second sample time ts/h2 where ts/h1>

    ts/h2,producing a digital counter signal at a counter and a ramp signal at a ramp, wherein the counter and the ramp are timed such that the counter counts from 0 to a predetermined number of counts, Cmax

    x, wherein Cmax is a number of counts corresponding to the number of bits desired for an analog to digital conversion of the detector signal and x is an integer corresponding to a subset of the number of bits, in approximately the time taken for the ramp to ramp from 0 to a predetermined voltage, vs1,sending the first S/H output to a comparator and comparing it to the ramp signal,starting the counter and the ramp, after a time >

    ts/h1,latching the count value if the ramp signal meets a threshold defined by the output of the first S/H before the counter counts to Cmax

    x, andif the latching does not happen before Cmax

    x is reached;

    while the counter continues, sending the second S/H signal to the comparator,while the counter continues, resetting the ramp to zero and restarting the ramp at a slope sufficient to ramp from 0 to a predetermined voltage vs2 in the time required for x counts, andlatching the count value if the output of the ramp signal meets a threshold defined by the output of the second S/H, wherein the count latched is a digitization of the detector signal;

    wherein a subset of count values greater than Cmax

    x comprise an excluded range of count values that do not correspond to possible values of the sampled signal, the excluded range corresponding to the time required for the restarted ramp to ramp from 0 to vs1.

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