Method and device for measuring the pulse by means of light waves with two wavelengths
First Claim
1. A method for determining a pulse of a person with a pulse measuring device wherein the pulse measuring device comprises a first light source adapted to generate light waves having a first wavelength, a second light source adapted to generate light waves having a second wavelength, and a photodetector disposed to sense light reflected by skin tissue and blood vessels and operably connected to provide measurement signals to a microcontroller unit, wherein the first and second wavelengths are different and determined so that the light waves with the first wavelength are sensitive to a pulse beat and to a movement of the person, and so that the light waves with the second wavelength are sensitive to movement,wherein the method comprises the steps of:
- (a)—
generating light waves with the first wavelength by the first light source and generating light waves with the second wavelength by the second light source, and transmitting both light waves in a direction of the skin of the person;
(b)—
detecting, using the photodetector, light waves of the first and second wavelengths reflected by the skin tissue and blood vessels and providing measurement signals to the microcontroller unit;
(c)—
calculating, using the microcontroller unit, at least one non-coherent power spectrum on the basis of a spectral coherence function γ
, wherein the spectral coherence function γ
accounts for the dependence between the measurement signals relating to the first wavelength and to the second wavelength by the formula SNC=(1−
γ
2)·
SAA, where SAA is the average Fourier power spectrum of the measurement signals relating to the first wavelength of the sensed light waves and where γ
2 is between 0 and 1; and
(d)—
determining the pulse of the person by the non-coherent power spectrum.
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Accused Products
Abstract
System and method to determine the heartbeat of a person by a pulse measuring device. Light waves are generated in the direction of the skin by two light sources with a first wavelength (λ1) which is sensitive to the pulse beat and movement of the person, and with a different second wavelength (λ2) which is sensitive to movement, wherein a photodetector detects the reflected light waves. A pulse is determined based on calculation made of at least one non-coherent power spectrum on the basis of a spectral coherence function γ which takes into account the dependence between the measurement signals relating to the first wavelength and to the second wavelength by the formula SNC=(1−γ2)*SAA, where SAA is the average Fourier power spectrum of the signals relating to the first wavelength, and where γ2 is between 0 and 1.
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Citations
15 Claims
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1. A method for determining a pulse of a person with a pulse measuring device wherein the pulse measuring device comprises a first light source adapted to generate light waves having a first wavelength, a second light source adapted to generate light waves having a second wavelength, and a photodetector disposed to sense light reflected by skin tissue and blood vessels and operably connected to provide measurement signals to a microcontroller unit, wherein the first and second wavelengths are different and determined so that the light waves with the first wavelength are sensitive to a pulse beat and to a movement of the person, and so that the light waves with the second wavelength are sensitive to movement,
wherein the method comprises the steps of: -
(a)—
generating light waves with the first wavelength by the first light source and generating light waves with the second wavelength by the second light source, and transmitting both light waves in a direction of the skin of the person;(b)—
detecting, using the photodetector, light waves of the first and second wavelengths reflected by the skin tissue and blood vessels and providing measurement signals to the microcontroller unit;(c)—
calculating, using the microcontroller unit, at least one non-coherent power spectrum on the basis of a spectral coherence function γ
, wherein the spectral coherence function γ
accounts for the dependence between the measurement signals relating to the first wavelength and to the second wavelength by the formula SNC=(1−
γ
2)·
SAA , whereSAA is the average Fourier power spectrum of the measurement signals relating to the first wavelength of the sensed light waves and where γ
2 is between 0 and 1; and(d)—
determining the pulse of the person by the non-coherent power spectrum. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A pulse measuring device, comprising
(a) an optical detection unit, including, (i)— - a first light source adapted to generate light waves with a first wavelength;
(ii) a second light source adapted to generate light waves with a second wavelength; and (iii) a photodetector disposed to sense light reflected by a person'"'"'s skin tissue and blood vessels and operably connected to provide measurement signals; and (b) a microcontroller unit, operably connected to the photodetector, and including, at least one processing unit adapted to calculate at least one non-coherent power spectrum on the basis of a spectral coherence function γ
, wherein the spectral coherence function γ
accounts for the dependence between the measurement signals provided by the photodetector, and relating to the first wavelength and to the second wavelength, by the formula SNC=(1−
γ
2)·
SAA , whereSAA is the average Fourier power of the measurement signals relating to the first wavelength of the sensed light waves and where γ
2 is between 0 and 1 in order to determine the pulse or a frequency of movement or the pulse and the frequency of movement of the person by the non-coherent power spectrum. - View Dependent Claims (11, 12, 13, 14, 15)
- a first light source adapted to generate light waves with a first wavelength;
Specification