Apparatus for quantifying concentration, method for quantifying concentration, and program for quantifying concentration

• US 20100256920A1
• Filed: 03/25/2010
• Published: 10/07/2010
• Est. Priority Date: 03/31/2009
• Status: Abandoned Application

• Current Assignee: National University Corporation Hokkaido University, Seiko Epson Corporation (Seiko Group)
• Original Assignee: National University Corporation Hokkaido University, Seiko Epson Corporation (Seiko Group)
• Inventors: Amano, Kazuhiko, Shimizu, Koichi
• Application Number:
  US12/659,932
• Publication Number:
  US 20100256920A1
• Time in Patent Office: Days
• US Class Current: 702/23
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: G01N 21/359 using near infrared light
• CPC Class Codes: G01N 21/47 Scattering, i.e. diffuse reflection G01N21/25, G01N21/41 take precedence G01N21/55 takes precedence

Abstract

An apparatus for quantifying concentration includes a temporal path-length distribution (TPD) storage unit configured to store a TPD model of a short-time-pulse of light, a time-resolved waveform storage unit configured to store a time-resolved waveform model of the short-time-pulse of light, a light irradiating unit configured to irradiate the short-time-pulse of light, a light receiving unit configured to receive a backscattered light, a measured light intensity acquisition unit configured to acquire a light intensity of the backscattered light, a TPD acquisition unit configured to acquire a TPD, a model light intensity acquisition unit configured to acquire the light intensity of the short-time-pulse of light, a light absorption coefficient calculating unit configured to calculate a light absorption coefficient, and a concentration calculating unit configured to calculate the concentration of a target component.

Claims

1. An apparatus for quantifying concentration that quantifies the concentration of a target component in an arbitrary target layer, which is in an observed object formed of a plurality of layers of light scattering medium, the apparatus comprising:

a TPD storage unit configured to store a TPD model of a short-time-pulse of light in each layer of the plurality of layers of light scattering medium, the short-time-pulse of light being irradiated to the observed object;

a time-resolved waveform storage unit configured to store a time-resolved waveform model of the short-time-pulse of light that is irradiated to the observed object;

a light irradiating unit configured to irradiate the short-time-pulse of light to the observed object;

a light receiving unit configured to receive a backscattered light, the short-time-pulse of light being backscattered from the observed object;

a measured light intensity acquisition unit configured to acquire a light intensity of the backscattered light that has been received by the light receiving unit at a predetermined time after the light irradiating unit had irradiated the short-time-pulse of light;

a TPD acquisition unit configured to acquire a TPD of each layer of the plurality of layers of light scattering medium at the predetermined time from the TPD model that has been stored by the TPD storage unit;

a model light intensity acquisition unit configured to acquire the light intensity of the short-time-pulse of light at the predetermined time from the time-resolved waveform model of the short-time-pulse of light that has been stored by the time-resolved waveform storage unit;

a light absorption coefficient calculating unit configured to calculate a light absorption coefficient of the arbitrary target layer, based on the light intensity that has been acquired by the measured light intensity acquisition unit, the TPD of each layer of the plurality of layers of light scattering medium that has been acquired by the TPD acquisition unit, and the light intensity that has been acquired by the model light intensity acquisition unit; and

a concentration calculating unit configured to calculate the concentration of the target component in the arbitrary target layer, based on the light absorption coefficient that has been calculated by the light absorption coefficient calculating unit.

2. The apparatus for quantifying concentration according to claim 1,

the measured light intensity acquisition unit acquiring the light intensities at a plurality of times t₁, . . . , t_m where the number of the times m is equal to or more than the number of the layers in the observed object n,

the light absorption coefficient calculating unit calculating the light absorption coefficient of the arbitrary target layer based on the equation:

3. The apparatus for quantifying concentration according to claim 2, the plurality of times including a peak time of the TPD model of each layer of the plurality of layers of light scattering medium when the measured light intensity acquisition unit acquires the light intensities.

4. The apparatus for quantifying concentration according to claim 1,

the measured light intensity acquisition unit acquiring the light intensities for at least a predetermined time length τ

since a predetermined time,

the light absorption coefficient calculating unit calculating the light absorption coefficient of the arbitrary target layer based on the equation;

5. The apparatus for quantifying concentration according to claim 1,

the light irradiating unit irradiating a plurality of lights that have wavelengths 1, . . . , q,

the light absorption coefficient calculating unit calculating the light absorption coefficients of the arbitrary target layer corresponding to wavelengths of the plurality of lights that have been irradiated by the light irradiating unit, and

the concentration calculating unit calculating the concentration of the target component in the arbitrary target layer based on the equation:

6. The apparatus for quantifying concentration according to claim 5,

the plurality of lights that have been irradiated by the light irradiating unit including the light with the wavelength, at which the light absorption coefficient of the target component is high.

7. The apparatus for quantifying concentration according to claim 5,

the plurality of lights that have been irradiated by the light irradiating unit including the lights with wavelengths, at which the orthogonality of absorption spectra is high each other among the primary components that form the observed object.

8. The apparatus for quantifying concentration according to claim 1,

the TPD model of a short-time-pulse of light in each layer of the plurality of layers of light scattering medium that has been stored by the TPD storage unit and the time-resolved waveform model of the short-time-pulse of light that has been stored by the time-resolved waveform storage unit are calculated by performing a simulation regarding the light absorption coefficient of the observed object as zero.

9. A method of quantifying concentration using an apparatus for quantifying concentration that quantifies the concentration of a target component in an arbitrary target layer, which is in an observed object formed of a plurality of layers of light scattering medium,

the apparatus for quantifying concentration comprising:

a TPD storage means that stores a TPD model of a short-time-pulse of light in each layer of the plurality of layers of light scattering medium, the short-time-pulse of light being irradiated to the observed object; and

a time-resolved waveform storage means that stores a time-resolved waveform model of the short-time-pulse of light that is irradiated to the observed object,

the method of quantifying concentration comprising;

a light irradiating means for that irradiates the short-time-pulse of light to the observed object;

a light receiving means that receives a backscattered light, the short-time-pulse of light being backscattered from the observed object;

a measured light intensity acquisition means that acquires a light intensity of the backscattered light that has been received by the light receiving means at a predetermined time after the light irradiating means had irradiated the short-time-pulse of light;

a TPD acquisition means that acquires a TPD of each layer of the plurality of layers of light scattering medium at the predetermined time from the TPD model that has been stored by the TPD storage means;

a model light intensity acquisition means that acquires the light intensity of the short-time-pulse of light at the predetermined time from the time-resolved waveform model of the short-time-pulse of light that has been stored by the time-resolved waveform storage means;

a light absorption coefficient calculating means that calculates a light absorption coefficient of the arbitrary target layer, based on the light intensity that has been acquired by the measured light intensity acquisition means, the TPD of each layer of the plurality of layers of light scattering medium that has been acquired by the TPD acquisition means, and the light intensity that has been acquired by the model light intensity acquisition means; and

a concentration calculating means that calculates the concentration of the target component in the arbitrary target layer, based on the light absorption coefficient that has been calculated by the light absorption coefficient calculating means.

10. A program that uses an apparatus for quantifying concentration that quantifies the concentration of a target component in an arbitrary target layer, the arbitrary target layer being an observed object formed of a plurality of layers of light scattering medium,

the apparatus for quantifying concentration comprising:

a TPD storage means that stores a TPD model of a short-time-pulse of light in each layer of the plurality of layers of light scattering medium, the short-time-pulse of light being irradiated to the observed object; and

a time-resolved waveform storage means that stores a time-resolved waveform model of the short-time-pulse of light that is irradiated to the observed object, and

the program makes the apparatus for quantifying concentration execute functions, the functions comprising;

a light irradiating means that irradiates the short-time-pulse of light to the observed object;

a light receiving means that receives a backscattered light, the short-time-pulse of light being backscattered from the observed object;

a measured light intensity acquisition means that acquires a light intensity of the backscattered light that has been received by the light receiving means at a predetermined time after the light irradiating means had irradiated the short-time-pulse of light;

a TPD acquisition means for acquiring a TPD of each layer of the plurality of layers of light scattering medium at the predetermined time from the TPD model that has been stored by the TPD storage means;

a model light intensity acquisition means that acquires the light intensity of the short-time-pulse of light at the predetermined time from the time-resolved waveform model of the short-time-pulse of light that has been store by the time-resolved waveform storage means;

a light absorption coefficient calculating means that calculates a light absorption coefficient of the arbitrary target layer, based on the light intensity that has been acquired by the measured light intensity acquisition means, the TPD of each layer of the plurality of layers of light scattering medium that has been acquired by the TPD acquisition means, and the light intensity that has been acquired by the model light intensity acquisition means; and

a concentration calculating means that calculates the concentration of the target component in the arbitrary target layer, based on the light absorption coefficient that has been calculated by the light absorption coefficient calculating means.