SYSTEM AND METHOD FOR DETERMINING VIDEO-BASED PULSE TRANSIT TIME WITH TIME-SERIES SIGNALS
First Claim
1. A method for determining an arterial pulse transit time between a proximal and distal region of a subject of interest from source video images acquired using a video imaging system, the method comprising:
- receiving a time-varying source images acquired over at least one channel of a video imaging system, said source images comprising video images captured of a proximal and distal region of an area of exposed skin of a subject of interest;
extracting, from said source images, a time-series signal for each of said proximal and distal regions;
computing a phase angle with respect to frequency for each of said time-series signals to obtain respective phase v/s frequency curves;
extracting, from each of said phase v/s frequency curves, corresponding slopes within a selected cardiac frequency range; and
computing a difference between said extracted slopes, said difference comprising an arterial pulse transit time for said subject between said proximal and distal regions.
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Abstract
What is disclosed is a system and method for determining a subject of interest'"'"'s arterial pulse transit time from time-varying source signals generated from video images. In one embodiment, a video imaging system is used to capture a time-varying source signal of a proximal and distal region of a subject of interest. The image frames are processed to isolate localized areas of a proximal and distal region of exposed skin of the subject. A time-series signal for each of the proximal and distal regions is extracted from the source video images. A phase angle is computed with respect to frequency for each of the time-series signals to produce respective phase v/s frequency curves for each region. Slopes within a selected cardiac frequency range are extracted from each of the phase curves and a difference is computed between the two slopes to obtain an arterial pulse transit time for the subject.
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Citations
24 Claims
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1. A method for determining an arterial pulse transit time between a proximal and distal region of a subject of interest from source video images acquired using a video imaging system, the method comprising:
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receiving a time-varying source images acquired over at least one channel of a video imaging system, said source images comprising video images captured of a proximal and distal region of an area of exposed skin of a subject of interest; extracting, from said source images, a time-series signal for each of said proximal and distal regions; computing a phase angle with respect to frequency for each of said time-series signals to obtain respective phase v/s frequency curves; extracting, from each of said phase v/s frequency curves, corresponding slopes within a selected cardiac frequency range; and computing a difference between said extracted slopes, said difference comprising an arterial pulse transit time for said subject between said proximal and distal regions. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A video based system for determining an arterial pulse transit time between a proximal and distal region of a subject of interest from source video images acquired using a video camera, the system comprising:
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a video imaging system for capturing a time-varying source images over at least one channel, said source images comprising video images captured of a proximal and distal region of an exposed area of skin of a subject of interest; and a processor in communication with said video camera and a memory, said processor executing machine readable instructions for performing; receiving a time-varying source images acquired over at least one channel of a video imaging system, said source images comprising video images captured of a proximal and distal region of an area of exposed skin of a subject of interest; extracting, from said source images, a time-series signal for each of said proximal and distal regions; computing a phase angle with respect to frequency for each of said time-series signals to obtain respective phase v/s frequency curves; extracting, from each of said phase v/s frequency curves, corresponding slopes within a selected cardiac frequency range; and computing a difference between said extracted slopes, said difference comprising an arterial pulse transit time for said subject between said proximal and distal regions. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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Specification