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Impaired operator detection and warning system employing eyeblink analysis

  • US 5,867,587 A
  • Filed: 05/19/1997
  • Issued: 02/02/1999
  • Est. Priority Date: 05/19/1997
  • Status: Expired due to Term
First Claim
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1. A method of detecting an impaired operator, comprising the steps of:

  • (a) employing an imaging apparatus which produces consecutive digital images including the face and eyes of an operator, each digital image comprising an array of pixel representing the intensity of light reflected from the face of the subject;

    (b) determining the location of a first one of the operator'"'"'s eyes within each digital image;

    (c) generating correlation coefficients, each of which quantifies the degree of correspondence between pixels associated with the location of the operator'"'"'s eye in an immediately preceding image in comparison to pixels associated with the location of the operator'"'"'s eye in a current image;

    (d) averaging the first N consecutive correlation coefficients generated to generate a first average correlation coefficient, wherein N corresponds to at least the number of images required to image a blink of the operator'"'"'s eye;

    (e) after the production of the next image by the imaging apparatus, averaging the previous N consecutive correlation coefficients generated to create a next average correlation coefficient;

    (f) repeating step (e) for each image frame produced by the imaging apparatus;

    (g) analyzing said average correlation coefficients to extract at least one parameter attributable to an eyeblink of said operator'"'"'s eye;

    (h) comparing each extracted parameter to an alert operator threshold associated with that parameter, said threshold being indicative of an alert operator; and

    (i) indicating that the operator may be impaired if any extracted parameter deviates from the associated threshold in a prescribed way.

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