Component Concentration Measuring Device
A measurement unit is attached to a measurement subject and measures acceleration in time series. A body movement calculation unit obtains the magnitude of body movement indicating the magnitude of a motion of the measurement subject based on acceleration measured by the measurement unit. A singular point extraction unit extracts, as a singular point, a time point at which the magnitude of body movement obtained by the body movement calculation unit exceeds a threshold value. A matching unit rectifies a change in a photoacoustic signal between before and after the singular point extracted by the singular point extraction unit.
1 .- 6 . (canceled)
7 . A component concentration measuring device comprising:
a light emitting device configured to emit a light beam toward a measurement site of a measurement subject, wherein the light beam has a wavelength that is absorbed by a measurement target substance;
a detector configured to detect a photoacoustic signal generated in the measurement site irradiated with the light beam in time series;
a measurement device configured to be attached to the measurement subject and measure an acceleration in time series;
a body movement calculator configured to obtain a magnitude of body movement of the measurement subject based on the acceleration measured by the measurement device;
a singular point extraction circuit configured to extract, as a singular point, a time point at which the magnitude of body movement obtained by the body movement calculator exceeds a first threshold value; and
a matching circuit configured to rectify a change in the photoacoustic signal between a time before and a time after the singular point extracted by the singular point extraction circuit.
8 . The component concentration measuring device according to claim 7 , wherein the matching circuit is configured to subtract an amount of the change in the photoacoustic signal between the time before and the time after the singular point extracted by the singular point extraction circuit from the photoacoustic signal after the singular point to rectify the change in the photoacoustic signal between the time before and the time after the singular point.
9 . The component concentration measuring device according to claim 7 , further comprising:
a determination circuit configured to determine whether or not an amount of the change in the photoacoustic signal between the time before and the time after the singular point extracted by the singular point extraction circuit exceeds a second threshold value; and
a selection circuit configured to select the singular point determined by the determination circuit to have the amount of the change in the photoacoustic signal between the time before and the time after the singular point exceeds the second threshold value from a plurality of singular points extracted by the singular point extraction circuit,
wherein the matching circuit is configured to rectify the change in the photoacoustic signal between the time before and the time after the singular point selected by the selection circuit.
10 . The component concentration measuring device according to claim 9 , further comprising a threshold value controller configured to increase the first threshold value used in the singular point extraction circuit when the determination circuit determines that the amount of the change in the photoacoustic signal between the time before and the time after the singular point extracted by the singular point extraction circuit does not exceed the second threshold value.
11 . The component concentration measuring device according to claim 7 , further comprising a concentration calculator configured to obtain a concentration of the measurement target substance using the photoacoustic signal.
12 . The component concentration measuring device according to claim 7 , wherein:
the measurement target substance is glucose; and
the light emitting device is configured to emit the light beam having the wavelength that is absorbed by the glucose.
13 . A component concentration measuring device comprising:
a light emitting device configured to emit a light beam toward a measurement site of a person, wherein the light beam has a wavelength that is absorbed by glucose;
a detector configured to detect a photoacoustic signal generated in the measurement site irradiated with the light beam in time series;
a measurement device configured to be attached to the person and measure an acceleration in time series;
a body movement calculator configured to obtain a magnitude of body movement of the person based on the acceleration measured by the measurement device;
a singular point extraction circuit configured to extract, as a singular point, a time point at which the magnitude of body movement obtained by the body movement calculator exceeds a threshold value; and
a matching circuit configured to rectify a change in the photoacoustic signal between a time before and a time after the singular point extracted by the singular point extraction circuit.
14 . The component concentration measuring device according to claim 13 , wherein the matching circuit is configured to subtract an amount of the change in the photoacoustic signal between the time before and the time after the singular point extracted by the singular point extraction circuit from the photoacoustic signal after the singular point to rectify the change in the photoacoustic signal between the time before and the time after the singular point.
15 . The component concentration measuring device according to claim 13 , further comprising a concentration calculator configured to obtain a concentration of the glucose using the photoacoustic signal.
16 . A method of measuring a component concentration, the method comprising:
emitting a light beam toward a measurement site of a measurement subject, wherein the light beam has a wavelength that is absorbed by a measurement target substance;
detecting a photoacoustic signal generated in the measurement site irradiated with the light beam in time series;
measuring an acceleration in time series using a measurement device attached to the measurement subject;
obtaining a magnitude of body movement of the measurement subject based on the acceleration measured by the measurement device;
extracting, as a singular point, a time point at which the magnitude of body movement exceeds a first threshold value; and
rectifying a change in the photoacoustic signal between a time before and a time after the singular point.
17 . The method according to claim 16 , wherein rectifying the change in the photoacoustic signal between the time before and the time after the singular point comprises subtracting an amount of the change in the photoacoustic signal between the time before and the time after the singular point from the photoacoustic signal after the singular point.
18 . The method according to claim 16 , further comprising:
determining whether or not an amount of the change in the photoacoustic signal between the time before and the time after the singular point exceeds a second threshold value; and
selecting the singular point determined to have the amount of the change in the photoacoustic signal between the time before and the time after the singular point that exceeds the second threshold value from a plurality of singular points.
19 . The method according to claim 18 , further comprising:
determining the amount of the change in the photoacoustic signal between the time before and the time after the singular point does not exceed the second threshold value; and
increasing the first threshold value upon determining that the amount of the change in the photoacoustic signal between the time before and the time after the singular point does not exceed the second threshold value.
20 . The method according to claim 16 , further comprising obtaining a concentration of the measurement target substance using the photoacoustic signal.
21 . The method according to claim 20 , wherein the measurement target substance is glucose.