Method for reducing noise, and pulse photometer using the method
First Claim
1. A method of processing an observed pulse wave data, comprising steps of:
- irradiating a living body with a first light beam having a first wavelength and a second light beam having a second wavelength which is different from the first wavelength;
converting the first light beam and the second light beam, which have been reflected or transmitted from the living body, into a first electric signal corresponding to the first wavelength and a second electric signal corresponding to the second wavelength, as the observed pulse wave data;
dividing a frequency band of the observed pulse wave data into a plurality of frequency ranges;
computing a light absorbance ratio obtained from the first electric signal and the second electric signal, for each one of the divided frequency ranges; and
determining that noise is not mixed into the observed pulse wave data in a case where a substantial match exists among light absorbance ratios computed for the respective frequency ranges.
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Abstract
A living body is irradiated with a first light beam having a first wavelength and a second light beam having a second wavelength which is different from the first wavelength. The first light beam and the second light beam, which have been reflected or transmitted from the living body, are converted into a first electric signal corresponding to the first wavelength and a second electric signal corresponding to the second wavelength, as the observed pulse data. A light absorbance ratio obtained from the first electric signal and the second electric signal is computed, for each one of frequency ranges dividing an observed frequency band. It is determined that noise is not mixed into the observed pulse wave data in a case where a substantial match exists among light absorbance ratios computed for the respective frequency ranges.
127 Citations
14 Claims
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1. A method of processing an observed pulse wave data, comprising steps of:
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irradiating a living body with a first light beam having a first wavelength and a second light beam having a second wavelength which is different from the first wavelength; converting the first light beam and the second light beam, which have been reflected or transmitted from the living body, into a first electric signal corresponding to the first wavelength and a second electric signal corresponding to the second wavelength, as the observed pulse wave data; dividing a frequency band of the observed pulse wave data into a plurality of frequency ranges; computing a light absorbance ratio obtained from the first electric signal and the second electric signal, for each one of the divided frequency ranges; and determining that noise is not mixed into the observed pulse wave data in a case where a substantial match exists among light absorbance ratios computed for the respective frequency ranges. - View Dependent Claims (2)
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3. A method of processing an observed pulse wave data, comprising steps of:
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irradiating a living body with a first light beam having a first wavelength and a second light beam having a second wavelength which is different from the first wavelength; converting the first light beam and the second light beam, which have been reflected or transmitted from the living body, into a first electric signal corresponding to the first wavelength and a second electric signal corresponding to the second wavelength, as the observed pulse wave data; and whitening the first electric signal and the second electric signal by an affine transformation using a known light absorbance ratio, in order to separate a pulse signal component and a noise component which are contained in the observed pulse wave data. - View Dependent Claims (4, 5, 6, 7, 8)
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9. A method of processing an observed pulse wave data, comprising steps of:
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irradiating a living body with a first light beam having a first wavelength and a second light beam having a second wavelength which is different from the first wavelength; converting the first light beam and the second light beam, which have been reflected or transmitted from the living body, into a first electric signal corresponding to the first wavelength and a second electric signal corresponding to the second wavelength, as the observed pulse wave data; dividing a frequency band of the observed pulse wave data into a plurality of frequency ranges; and whitening the first electric signal and the second electric signal to separate a pulse signal component and a noise component which are contained in the observed pulse wave data, for each one of the divided frequency ranges. - View Dependent Claims (10, 11)
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12. A pulse photometer comprising:
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a first light source adapted to irradiate a living body with a first light beam having a first wavelength; a second light source adapted to irradiate the living body with a second light beam having a second waveform which is different from the first wavelength; a converter operable to convert the first light beam and the second light beam subsequent to irradiating the living body to a first and second electrical signals, respectively, as observed data; a processor operable to divide a frequency band of the observed data into a plurality of frequency ranges, compute a light absorption ratio based on the first and second electrical signals for each one of the divided frequency ranges, and determine that noise is not mixed in the observed data in case where a substantial match exists among light absorbance ratios computed for the respective range of frequencies.
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13. A pulse photometer comprising:
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a first light source adapted to irradiate a living body with a first light beam having a first wavelength; a second light source adapted to irradiate the living body with a second light beam having a second waveform which is different from the first wavelength; a converter operable to convert the first light beam and the second light beam subsequent to irradiating the living body to a first and second electrical signals, respectively, as observed pulse wave data; a processor operable to whiten the first and the second electrical signals by affine transformation using a known light absorbance ratio to separate a pulse signal component and a noise component contained in the observed pulse wave data.
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14. A pulse photometer, comprising:
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a first light source adapted to irradiate a living body with a first light beam having a first wavelength; a second light source adapted to irradiate the living body with a second light beam having a second waveform which is different from the first wavelength; a converter operable to convert the first light beam and the second light beam subsequent to irradiating the living body to a first and second electrical signals, respectively, as observed data; a processor operable to divide a frequency band of the observed data into a plurality of frequency ranges, and whiten the first and the second electrical signals to separate a pulse signal component and a noise component contained in the observed data for each one of the divided frequency ranges.
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Specification