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Video-based estimation of heart rate variability

  • US 8,977,347 B2
  • Filed: 06/25/2012
  • Issued: 03/10/2015
  • Est. Priority Date: 06/25/2012
  • Status: Active Grant
First Claim
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1. A method for estimating heart rate variability from a video captured of a subject of interest, the method comprising:

  • receiving a video captured of a target area of a region of exposed skin of a subject of interest where a photoplethysmographic (PPG) signal of said subject can be registered, said video comprising video images captured by a video camera;

    selecting a first batch of said video images for processing;

    identifying a first region of interest (ROI) in said selected batch of video images for processing; and

    A) processing pixels in said ROI of said selected batch of said video images to obtain a time-series signal containing a PPG signal captured by said imaging channel of said video camera;

    B) processing said time-series signal to extract said PPG signal;

    C) calculating a power spectral density function on said PPG signal;

    D) using a peak detection algorithm to detect low frequency and high frequency components over a pre-defined frequency range from said power spectral density function;

    E) in response to a low frequency peak or a high frequency peak not being detected in said power spectral density function, performing at least one of;

    (i) identifying a next ROI which is different than said first ROI and repeating again at step (A);

    (ii) selecting a next batch of video images which is at least partially different than said first batch of video images and repeating again at step (A)(iii) using signal reconstruction to introduce one or more missing peaks on said PPG signal and then repeating steps (C), (D) and (F); and

    F) determining a ratio of said low and high frequency components over said interval of said selected batch, said ratio comprising said subject'"'"'s estimated heart rate variability for said interval.

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