Device, system and method for determining the concentration of a substance in the blood of a subject
First Claim
1. A device for determining the concentration of a substance in the blood of a subject, comprising:
- at least one processor programmed to;
receive detection signals reflected back or transmitted through a skin area of the subject in response to irradiation of the skin area by a radiation signal,extract at least three photo-plethysmography, PPG, signals at different wavelengths from said detection signals,direct current (DC) normalize said at least three PPG signals and to form a first difference signal between a first normalized PPG signal and a second normalized PPG signal and a second difference signal between a third normalized PPG signal and one other of the at least three normalized PPG signals and to form a ratio between estimated alternating current (AC) amplitudes of said first difference signal and said second difference signal, andcalculate the concentration of a substance in the blood of the subject based on said ratio.
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Accused Products
Abstract
A device for determining the concentration of a substance in the blood of a subject, such as the oxygen saturation, which device reduces or removes the influence of specular reflection and/or subject motion, comprises an input unit for receiving detection signals reflected back or transmitted through a skin area of the subject in response to irradiation of the skin area by a radiation signal, a signal extraction unit for extracting at least three photo-plethysmography, PPG, signals at different wavelengths from said detection signals, a processing unit for normalizing said at least three PPG signals and forming a first difference signal between a first normalized PPG signal and a second normalized PPG signal and a second difference signal between a third normalized PPG signal and one other of the at least three normalized PPG signals and for forming a ratio between said first difference signal and said second difference signal, and an concentration detection unit for calculating the concentration of a substance in the blood of the subject based on said ratio.
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Citations
20 Claims
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1. A device for determining the concentration of a substance in the blood of a subject, comprising:
at least one processor programmed to; receive detection signals reflected back or transmitted through a skin area of the subject in response to irradiation of the skin area by a radiation signal, extract at least three photo-plethysmography, PPG, signals at different wavelengths from said detection signals, direct current (DC) normalize said at least three PPG signals and to form a first difference signal between a first normalized PPG signal and a second normalized PPG signal and a second difference signal between a third normalized PPG signal and one other of the at least three normalized PPG signals and to form a ratio between estimated alternating current (AC) amplitudes of said first difference signal and said second difference signal, and calculate the concentration of a substance in the blood of the subject based on said ratio. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A computer readable non-transitory medium having instructions stored thereon which, when carried out on a computer, cause the computer to perform a method for determining the concentration of a substance in the blood of a subject, the method comprising:
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receiving detection signals reflected back or transmitted through a skin area of the subject in response to irradiation of the skin area by a radiation signal, extracting at least three photo-plethysmography, PPG, signals at different wavelengths from said detection signals, direct current (DC) normalizing said at least three PPG signals, forming a first difference signal between a first PPG signal and a second PPG signal and a second difference signal between a third PPG signal and one other of the at least three PPG signals, forming a ratio between estimated AC amplitudes of said first difference signal and said second difference signal, and calculating the concentration of a substance in the blood of the subject based on said ratio.
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15. A device for determining the oxygen saturation of a subject, comprising:
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at least one processor programmed to; receive detection signals reflected back or transmitted through a skin area of the subject in response to irradiation of the skin area by a radiation signal, extract at least three photo-plethysmography, PPG, signals at different wavelengths from said detection signals, direct current (DC) normalize said at least three PPG signals and to form a first difference signal between a first normalized PPG signal and a second normalized PPG signal and a second difference signal between a third normalized PPG signal and one other of the at least three normalized PPG signals and to form a ratio between estimated alternating current (AC) amplitudes of said first difference signal and said second difference signal, and calculate the oxygen saturation of the subject based on said ratio. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification