Non-destructive measurement device for light scattering materials

Abstract

To provide a non-destructive measurement device for a light scattering body, capable of estimating a property characteristic value inside an analyte with good measurement accuracy without the need for an analytical curve.SOLUTION: A non-destructive measurement device for a light scattering body includes: a light source 7 that generates light having a plurality of wavelengths; a light irradiation unit that has a light emission port and irradiates the light scattering body with the light having the plurality of wavelengths from the light emission port; two light-receiving units that have light-receiving ports at positions having distances different from each other from the center of the light emission port and receive reflection light after the light having the plurality of wavelengths penetrates an inside of the analyte; a light detection unit 50 that detects light intensity of the light received by each of the light-receiving ports; and a calculation processing unit 30 that calculates a reflectance obtained by taking a ratio of the light intensity of the two light-receiving units to calculate a property characteristic value inside the analyte. The calculation processing unit calculates a reflectance for each wavelength to calculate a relative absorbance ratio. Further, the calculation processing unit obtains a plurality of theoretical values of the relative absorbance ratio using the property characteristic value as a variable corresponding to the relative absorbance ratio to output the property characteristic value under a condition that the theoretical value is most approximate to the relative absorbance ratio.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a non-destructive measuring device for a light scatterer that measures the property characteristic values ​​of a light scatterer as a test object. For example, the present invention relates to a non-destructive measuring device for a light scatterer that is suitable as a non-invasive measuring device for measuring the composition of a living body, such as water, fat, or protein, as a test object. [Background technology]

[0002] Conventionally, various non-destructive measurement methods for light scattering bodies have been known, which optically measure characteristic values ​​relating to the internal properties of a specimen made of a light scattering body, such as measuring the sugar content of fruit, fat and moisture of meat, etc. For example, Patent Document 1 describes a method and device for measuring the component contents of beef, which receives reflected light from a test beef carcass, measures absorbance spectra for wavelengths in the near-infrared region, calculates second derivatives of these absorbance spectra, and estimates the fat and water contents from the calculation results. Here, to estimate the component contents of beef from the second derivatives of the absorbance spectrum, a calibration curve relating the second derivatives of the absorbance spectrum to the component contents is prepared in advance by multiple regression analysis or the like, and the component contents are estimated from the calculation results of the second derivatives of the absorbance spectrum measured using the calibration curve.

[0003] Furthermore, Patent Document 2 describes a non-destructive measurement device for light scatterers that irradiates a measurement site with light of three different wavelengths, receives the reflected light that has passed through the measurement site at two locations at different distances, detects the amount of reflected light, calculates a reflectance for each wavelength, which is the ratio of the amount of reflected light of the same wavelength at the two detected locations, and estimates a property characteristic value of a test object, such as the sugar content of a fruit, from the relative absorbance ratio calculated using the reflectance for each wavelength. Here, to estimate the property characteristic value of a test object from the relative absorbance ratio, a calibration curve relating the relative absorbance ratio to the property characteristic value is created in advance by multiple regression analysis or the like, and the property characteristic value is estimated from the calculation result of the relative absorbance ratio measured using the calibration curve. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 9-119894 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-271575 Summary of the Invention [Problem to be solved by the invention]

[0005] In order to estimate the component contents of beef using the technique described in Patent Document 1, it is necessary to prepare in advance a calibration curve expressed as a polynomial of the second derivative of absorbance. When estimating the property characteristic value of a specimen using the technique described in Patent Document 2, it is also necessary to prepare in advance a calibration curve expressed as a polynomial of the relative absorbance ratio. To create a calibration curve, it is necessary to determine the regression coefficients of the calibration curve, which is expressed as a polynomial with the second derivative of absorbance or the relative absorbance ratio as explanatory variables, using statistical processing such as multiple regression analysis, with the characteristic values ​​of the test specimen, such as the moisture and fat content of beef or the sugar content of fruit, as the objective variable. This requires crushing the sample to analyze the objective variable, such as the component content, or preparing 50–100 samples with a range of characteristic values, such as the component content, that is approximately 10 times the measurement precision. However, both of these methods are difficult to achieve when measuring living subjects, including humans, and creating a calibration curve without destroying the sample is virtually impossible. For these reasons, it is not easy to use the techniques described in Patent Documents 1 and 2 to measure the components of human tissue.

[0006] In view of the above circumstances, an object of the present invention is to provide a non-destructive measuring device for a light scattering medium that can estimate property characteristic values ​​inside a test object with good measurement accuracy without requiring a calibration curve. [Means for solving the problem]

[0007] The present invention is a non-destructive measurement device for light scattering bodies, comprising: a light source that generates light of multiple wavelengths; a light irradiating unit having a light outlet that emits light of multiple wavelengths and irradiating the light of multiple wavelengths from the light outlet toward a single irradiation area on a test body made of a light scattering body; two light receiving units having light receiving units at positions different distances from each other relative to the center of the light outlet and receiving reflected light after the light of multiple wavelengths irradiated from the light outlet passes through the inside of the test body; a light detection unit that detects the light intensity of the light received by each of the light receiving units; and an arithmetic processing unit that calculates a reflectance, which is the ratio of the light intensities of the two light receiving units, for each of multiple wavelengths and calculates a property characteristic value of the inside of the test body based on the reflectance. The multiple wavelength light has multiple wavelengths λ i Includes light (i=1,2,…,n). The light detection unit detects the wavelength λ of the reflected light received by the two light receiving units that are located at distances ρ1 and ρ2 (where ρ1<ρ2). i The total amount of light received at each 1i , J 2i When the wavelength λ is detected as i Reflectance R i is calculated, and the relative absorbance ratio γ k Calculate multiple values. Furthermore, the relative absorbance ratio γ k The theoretical value γ^ of the relative absorbance ratio with the property characteristic value as a variable corresponds to k Obtain multiple values ​​and calculate the theoretical value γ^ k and the relative absorbance ratio γ k The property characteristic value under the condition that most closely matches the above is output. R i =J 2i / J 1i …(1) gamma k =ln(R k+2 / R1) / ln(R2 / R1) …(2) [Effects of the Invention]

[0008] The non-destructive measuring device for a light scattering medium according to the present invention can estimate property characteristic values ​​inside a test object with good measurement accuracy without requiring a calibration curve. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram showing a general configuration of a nondestructive measuring device for a light scattering medium according to a first embodiment of the present invention. [Figure 2] 1A is a side view of the light receiving section of the nondestructive measuring device, and FIG. 1B is a cross-sectional view taken along line BB in FIG. [Figure 3] FIG. 2 is a functional block diagram showing the functional configuration of a control system of the nondestructive measuring device. [Figure 4] 3A to 3C are diagrams showing a process when the nondestructive measuring device is used. [Figure 5] 1A is a side view of a light receiving section in a first modified example of the nondestructive measuring device, and FIG. 1B is a cross-sectional view taken along line BB in FIG. [Figure 6] 10(a) is a side view of a light receiving section in a second modified example of the nondestructive measuring device, and FIG. 10(b) is a side view of a light receiving section in a third modified example of the nondestructive measuring device. [Figure 7] FIG. 2 is a schematic diagram showing a general configuration of a nondestructive measuring device for a light scattering medium according to a second embodiment of the present invention. [Figure 8] Graph (a) shows the measured values ​​of reflectance in a measurement example using a non-destructive measurement device, and graph (b) shows the measured values ​​of relative absorbance ratio in the same measurement example and fitting using the measured values. [Figure 9] 10 is a graph showing fitting using measured values ​​of reflectance. DETAILED DESCRIPTION OF THE INVENTION

[0010] A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic diagram showing the general configuration of a nondestructive measuring device for a light scattering medium according to this embodiment (hereinafter simply referred to as "nondestructive measuring device").

[0011] As shown in FIG. 1, the nondestructive measuring device 1 is a device that optically measures property characteristic values ​​inside a test object 2 made of a light scattering medium that scatters light incident from the outside and emits it to the outside. The nondestructive measuring device 1 includes a light source 7, a light source control unit 10, a sensor probe 3 (fixed holding member), a light detection unit 50, a signal processing unit 17, a central control unit 18, and a display unit 19.

[0012] There are various types of specimens 2 to be measured, including fruits and vegetables, living animals and plants, food, beverages, soil samples, and other specimens for quantitative analysis, as well as solid, powder, jelly, liquid, and other samples. The property characteristic value to be measured may be any property characteristic value that indicates a property correlated with the degree of absorption of incident light by the subject, and examples include the water content, fat content, protein content, tissue oxygen saturation, hemoglobin concentration of a living body, the sugar content and acidity of fruits and vegetables, the water content and protein content of wheat flour, the starch concentration of potatoes, the amount of fertilizer components such as nitrogen in soil, etc. In addition, the scattering coefficient of the above-mentioned various subjects can also be used as a property characteristic value. The nondestructive measuring device 1 may be a device that measures one of the above-mentioned property characteristic values, or may be a device that can switch between and measure multiple property characteristic values. In the latter case, the measurer may manually set the property characteristic value to be measured and measurement conditions for each measurement using an operation unit 20 (described later) that performs operation input, or the device may be configured to automatically and continuously measure multiple property characteristic values ​​for the same specimen. In the following explanation, as an example, the case where the device is used as a non-invasive measuring device for measuring moisture, fat, and protein in living organisms and meat will be mainly explained.

[0013] Light source 7 generates light of a plurality of wavelengths. For example, when non-invasively measuring moisture, fat, protein, etc. of a living body or meat, the wavelength of the light source can be selected and set within the range of 600 nm to 1100 nm. In one example, light source 7 is a light source that oscillates light with n different center wavelengths λ1, λ2, ..., λn, and a wavelength-tunable laser can be used. A wavelength-tunable laser can selectively oscillate laser light having a specific center wavelength from the wavelength range required for measurement. Light source 7 can also be configured using multiple semiconductor lasers or light-emitting diodes that can oscillate light with each of the above center wavelengths.

[0014] The light source control unit 10 includes a power supply (not shown), and controls the wavelength, intensity, and light emission timing of the light emitted from the light source 7 in response to a control signal from the central control unit 18 . In this embodiment, control is performed in response to a control signal from the central control unit 18 to sequentially emit light of central wavelengths λ1, λ2, . . . , λn at preset intensities and emission timings. The coupling lens 9 is an optical element that condenses the light emitted from the light source 7 and optically couples it as irradiation light 8 to the optical fiber cable 4, which will be described later.

[0015] Fig. 2(a) is a side view of the light receiving section of the nondestructive measuring device 1 as viewed in the direction A in Fig. 1. Fig. 2(b) is a cross-sectional view taken along line BB in (a). As shown in Figures 2(a) and 2(b), the sensor probe 3 guides irradiation light 8 of a specific wavelength emitted from a light source 7 to the subject surface 2a of the subject 2, and also guides light from the subject surface 2a to a light detection unit 50, and has a configuration in which the ends of optical fiber cables 4, 5, and 6 are fixed.

[0016] 1 and 2, the optical fiber cable 4 (light irradiation unit) is composed of an optical fiber 4b having an emission end face 4a (light emission port) at one end and an incidence end face 4c at the other end. The emission end face 4a is fixed and aligned on the same plane as the probe end face 3a that faces the object surface 2a. The optical fiber cables 5, 6 (light receiving sections) are made up of optical fibers 5b, 6b each having an incident end face 5a, 6a (light receiving port) at one end and an exit end face 5c, 6c at the other end, and are attached to the sensor probe 3. The incident end faces 5a and 6a are arranged on two concentric circles with radii ρ1 and ρ2, respectively, in the same radial direction from the center position of the output end face 4a, and are aligned on the same plane as the probe end face 3a. In other words, the radii ρ1 and ρ2 correspond to the distances between the incident end faces 5a and 6a and the center position of the output end face 4a, and ρ2 > ρ1.

[0017] The structure and material of the optical fibers 4b, 5b, and 6b preferably have low transmission loss, but are not particularly limited as long as the characteristic values ​​for calibration, such as the NA of the light receiving port and the transmission loss characteristics of the optical fiber for each wavelength, are known. For example, they may be multimode or single mode, and the refractive index distribution may be an appropriate distribution. They may also be glass fiber or plastic fiber. Furthermore, each of the optical fibers 4b, 5b, and 6b may be made up of one or more core wires each having a predetermined core diameter.

[0018] It is preferable that the sensor probe 3 has light absorption properties at least on the probe end surface 3a so that light reflected from the specimen surface 2a does not become measurement noise. The degree of light absorption depends on the required measurement accuracy, but for example, in measuring the composition of a living body or the sugar content of fruits and vegetables, a reflectance of 10% or less is preferable, and 5% or less is more preferable. In this embodiment, a black grade polyacetal material is used as the material having such good light absorption properties.

[0019] The light detection unit 50 includes focusing lenses 13 and 14 that focus the light beams 11 and 12 from the object surface 2a, which enter the optical fibers 5b and 6b through the incident end faces 5a and 6a, and are emitted collectively from the optical fibers 5b and 6b through the exit end faces 5c and 6c, respectively, and photodetectors 15 and 16 whose light receiving surfaces are located at the respective focusing positions. Photodiodes or the like having sufficient sensitivity to wavelength light can be used as the photodetectors 15 and 16 .

[0020] FIG. 3 is a functional block diagram for explaining the functional configuration of a control system of the nondestructive measuring device for a light scattering medium according to the first embodiment of the present invention. The signal processing unit 17 amplifies the detection outputs from the photodetectors 15 and 16, calibrates the detection outputs based on preset calibration values, converts them into digital signals converted into the total amount of light received in the light receiving range of the incident end faces 5 a and 6 a, and sends them to the calculation processing unit 30. Hereinafter, the wavelength λ from the incident end face 5a will be i The total received light amount corresponding to (i=1,2,…,n) is J1i , and the same from the incident end face 6a is J 2i , respectively. Here, the wavelengths of the emitted light beams 11 and 12 incident on each of the light sources are switched by the light source control unit 10 automatically determining the wavelength switching timing based on a clock signal sent from the central control unit 18.

[0021] The central control unit 18 controls the measurement operation of the nondestructive measuring device 1. The central control unit 18 is electrically connected to the light source control unit 10, the signal processing unit 17, the display unit 19, and the operation unit 20, and controls the operation of each unit by communicating various control signals and data with each unit. 3, the functional block configuration of the central control unit 18 is made up of a device control unit 21, a display control unit 22, and an arithmetic processing unit 30. The central control unit 18 may be made up of multiple pieces of hardware that perform the operations of the respective functional blocks, or may be made up of a computer equipped with a CPU, memory, an input / output interface, an appropriate storage unit, etc., and programs corresponding to the operations of the respective functional blocks may be executed by this computer.

[0022] The device control unit 21 coordinates and controls the operation of the light source control unit 10, signal processing unit 17, calculation processing unit 30, and display control unit 22 in response to operation input from the operation unit 20 operated by the measurer, and performs measurement start, end, and measurement operations. The device control unit 21 sends control signals to the light source control unit 10 and the signal processing unit 17 to control the emission and detection processes of light of multiple wavelengths, and also sends a clock signal to synchronize the respective operations. The device control unit 21 notifies the calculation processing unit 30 of the property characteristic values ​​measured in response to the operation input of the operation unit 20, and initializes the processing operation of the calculation processing unit 30. The device control unit 21 sends information such as operation inputs from the operation unit 20 and measurement results sent from the calculation processing unit 30 to the display control unit 22 and controls the display unit 19 to display the information.

[0023] The display control unit 22 converts the information sent from the device control unit 21 into a video signal for display on the display unit 19 .

[0024] The arithmetic processing unit 30 of this embodiment has a reflectance calculation unit 31, a relative absorbance ratio calculation unit 32, a property characteristic value calculation unit 33, and a data storage unit . The reflectance calculation unit 31 calculates the J 1i , J 2i From the above equation (1), the reflectance R i Calculate.

[0025] The relative absorbance ratio calculation unit 32 calculates the n kinds of wavelengths λ calculated by the reflectance calculation unit 31. i Reflectance R i From the above equation (2), the relative absorbance ratio γ k and sends it to the property characteristic value calculation unit 33. That is, m relative absorbance ratios γ k Calculate (k=1,2,…,m). γ1=ln(R3 / R1) / ln(R2 / R1)…(2a) γ2=ln(R4 / R1) / ln(R2 / R1)…(2b) γ3=ln(R5 / R1) / ln(R2 / R1)…(2c) … gamma m =ln(R m+2 / R1) / ln(R2 / R1)…(2m)

[0026] In the above explanation, R i The term "reflectance" is used because it is the ratio of the amount of light that is incident on the surface 2a of the subject, passes through the inside of the subject, and is reflected back to the surface 2a of the subject. However, the ratio of the amount of light that is reflected here can also be considered as "transmittance" because the amount of light that passes through the inside of the subject 2 and is transmitted to a position away from the incident position is detected.

[0027] The property characteristic value calculation unit 33 calculates the theoretical value γ^ of the relative absorbance ratio. k Calculate the theoretical value of the relative absorbance ratio γ^ kIn the calculation, the property characteristic values ​​are treated as variables, and the m relative absorbance ratios γ k (k=1,2,…,m) and its theoretical value γ^ k The property characteristic value is calculated using the nonlinear least squares method under the condition that the above conditions are met. As the nonlinear least squares method, known analytical algorithms such as the Gauss-Newton method and the Levenberg-Marquardt method can be used. The radii ρ1 and ρ2 of the concentric circles on which the light receiving apertures are arranged and the absorption coefficients of the various compositions of the specimen are values ​​stored in advance in the data storage unit 34. In this calculation, the temperature T m may be treated as a variable, one of the property characteristic values. Alternatively, a value obtained by separately inputting the temperature measured at the time of, or before or after, the reflectance measurement from the operation unit 20 may be used. Alternatively, a temperature detection unit for measuring the temperature of the specimen may be provided, and the temperature of the specimen may be measured simultaneously with the reflectance measurement, and the value may be input to the property characteristic value calculation unit.

[0028] The data storage unit 34 stores the calibration coefficients, the radii ρ1 and ρ2 of the concentric circles on which the light receiving ports are arranged, the absorption coefficients of various compositions of the specimen, and boundary conditions. The data storage unit 34 can be configured using various storage units, such as a ROM, an external storage medium, or an external storage unit.

[0029] The operation of the nondestructive measuring device 1 according to this embodiment, which is configured as described above, during use will be described. First, as shown in FIG. 4, the user places the sensor probe 3 with the probe end surface 3a in contact or nearly in contact with the surface 2a of the subject 2 at the measurement site. 4 is a schematic diagram, and the subject surface 2a is shown as a flat surface. However, the subject surface 2a varies depending on the shape of the subject 2. For example, when the measurement site is an arm or a palm, it is natural that the subject surface 2a will have unevenness or curvature. Also, in FIG. 4, a gap is shown between the probe end surface 3a and the subject surface 2a. However, a slight gap may be provided so that the probe end surface 3a and the subject surface 2a are in approximate contact, or the probe end surface 3a and the subject surface 2a may be in complete contact. In this embodiment, it is preferable to bring the output end surface 4a as close as possible to the subject 2, but the subject surface 2a and the input end surfaces 5a and 6a do not necessarily have to be in contact.

[0030] When the user inputs an instruction to start measurement from the operation unit 20, the central control unit 18 outputs n kinds of central wavelengths λ1, λ2, . . . , λ3 from the light source 7 via the light source control unit 10. n The laser beams 8 are sequentially emitted. The irradiation light 8 is optically coupled to the incident end face 4c of the optical fiber 4b by the coupling lens 9. The irradiating light 8 propagates through the inside of each optical fiber 4b and is irradiated from the emitting end face 4a arranged on the probe end face 3a of the sensor probe 3 towards the object surface 2a.

[0031] The light irradiated onto the surface 2a of the subject is divided into reflected light that is reflected by the surface 2a of the subject, and transmitted light that enters the interior of the subject 2 and passes through the interior. The reflected light is repeatedly reflected between the object surface 2a and the probe end surface 3a and is attenuated. The transmitted light is scattered depending on the internal properties of the subject 2, and after passing through various optical paths, some of the light reaches the subject surface 2a again and is emitted to the outside of the subject 2, where it enters the optical fibers 5b and 6b at the positions of the incident end faces 5a and 6a, respectively. For example, as shown in FIG. 4, internal light 25A and 26A, which are part of the light that has entered the inside of the subject 2, are incident on the incident end surface 5a and the incident end surface 6a, respectively. The internal light beams 25A and 26A are transmitted through their respective optical paths while being scattered in accordance with the properties of the interior of the subject 2 between the exit end face 4a and the incident end face 5a (6a) and the distance between the exit end face 4a and the incident end face 5a (6a). Therefore, the light intensity of the exit light beams from each beam contains information on the properties of the subject 2 between the exit end face 4a and the incident end face 5a (6a).

[0032] In this embodiment, light containing information about the internal properties of the subject 2 according to the positions of the incident end faces 5a, 6a is transmitted through the optical fibers 5b, 6b and is output together from the output end faces 5c, 6c as output light 11, 12, respectively. These output light beams are then collected by collecting lenses 13, 14, respectively, and received by photodetectors 15, 16. The photodetectors 15, 16 send detection output signals proportional to the intensity of the received light to a signal processing unit 17.

[0033] The signal processing unit 17 identifies the detection outputs of the photodetectors 15 and 16 for each wavelength based on the reception timing, and calculates the wavelength λ based on the calibration information created in advance for each wavelength. i Total light received per J 1i , J 2i and sends it to the arithmetic processing unit 30. Here, the calibration information is given as correction coefficients for correcting the transmission loss of the optical fibers 5b and 6b, the transmittance of the condenser lenses 13 and 14, and the sensitivity characteristics of the photodetectors 15 and 16 for each wavelength. And the total amount of light received for each wavelength J 1i , J 2i is divided by the light receiving area of ​​each of the incident end faces 5a and 6a, and the light intensity is I 1i , I 2i Then, J 1i , J 2i are calculated using the following formulas (4) and (5), respectively. J 1i =I 1i ×A1…(4) J 2i =I 2i ×A2…(5) Here, A1 and A2 are the light receiving areas of the incident end faces 5a and 6a, respectively.

[0034] The reflectance calculation unit 31 calculates the wavelength λ according to equation (1). i Reflectance R i and sends the respective calculation results to the relative absorbance ratio calculation unit 32.

[0035] The relative absorbance ratio calculation unit 32 calculates the relative absorbance ratio γ k and sends it to the property characteristic value calculation unit 33. Here, the two different wavelengths λ appearing in the formula (2) i , λ j (i≠j) reflectance ratio R j / R i is expressed by the following formula (6) based on the definition of formula (1). R j / R i =(J 2j ×J 1i ) / (J 1j ×J 2i )…(6)

[0036] Using the relationship between equations (4) and (5), equation (6) can be expressed as the following equation (6a). R j / R i =(J 2j ×J 1i ) / (J 1j ×J 2i ) =(A1×A2×I 2j ×I 1i ) / (A1×A2×I 1j ×I 2i ) =(I 2j ×I 1i ) / (I 1j ×I 2i )…(6a) From equation (6a), the reflectance ratio of two different wavelengths is the light intensity per unit area I divided by the light receiving area of ​​each of the incident end faces 5a and 6a. 1i , I 2i , and I 1j , I 2j It can be seen that this is independent of the light receiving areas A1 and A2.

[0037] The property characteristic value calculation unit 33 calculates the theoretical value γ^ of the relative absorbance ratio. k Calculate the theoretical value of the relative absorbance ratio γ^ k In the calculation, the property characteristic values ​​are treated as variables, and the m relative absorbance ratios γ k (k=1,2,…,m) and its theoretical value γ^ k The property characteristic value is calculated using the nonlinear least squares method under the condition that the values ​​of the properties and the characteristics are consistent. Below, the theoretical value of the relative absorbance ratio γ^ k This explains how to calculate this. The object 2 shown in FIG. S’ and absorption coefficient μ a Assuming that the light scattering medium has the above property characteristic values ​​uniformly distributed in space, the theoretical value I^1 of the light intensity per unit area of ​​the reflected light 25A that passes through the medium and is received by the light-receiving surface 5a is theoretically expressed by the following equation (7) (TJ Farrel et al., Med. Phys. 19 (1992) 879.).

[0038]

number

[0039] Here, P0 represents the intensity of the light irradiated from the exit end surface 4a onto the object 2. z0 represents the reduced scattering coefficient μ S’ Using z0=1 / μ S’ α and D are the absorption coefficients μ of the object 2 a and the reduced scattering coefficient μ S’ Using α=[3μ a (μ a +μ S’ )] 0.5 , D=1 / 3 / (μ a +μ S’ ) and r1 is expressed as r1 2 =z0 2 +ρ1 2 and r2 is expressed as r2 using the boundary condition Ω. 2 =(z0+4ΩD) 2 +ρ1 2where ρ1 represents the distance between the centers of the output end face 4a and the input end face 5a. The boundary condition Ω is expressed by the following equation (8).

[0040]

number

[0041] In equation (8), n rel is the refractive index ratio between the refractive index n1 of the air before the light is incident, and the refractive index n2 of the object after the light is incident, with the object surface as the boundary, and n rel = n2 / n1. The refractive index n1 of air is 1.00, and the refractive index n2 of living bodies such as chicken, pork, and humans is 1.38-1.44 (see F.P. Bolin et al., Appl. Opt. 28 (1989) 2297, M. Ohmi et al., IEEE. Trans. Biomed. Eng. 47 (2000) 1266, etc.). Therefore, the refractive index ratio n rel is 1.38 to 1.44. Therefore, the boundary condition Ω in the living body is 3.1 to 3.5 according to equation (8).

[0042] On the other hand, the theoretical value I^2 of the light intensity per unit area of ​​the reflected light 26A that passes through the interior and is received by the light receiving surface 6a is given by the equation (7) expressing the theoretical value I^1 of the light intensity, where the separation distance ρ1 is changed to the separation distance ρ2.

[0043] Next, the absorption coefficient μ a In this example, the combined volume fraction of water, protein, and fat is assumed to be 1.0 (100%), and the volume fraction of fat is k f Therefore, the volume fraction of water and protein excluding fat, k as is k as =1.0-k f It is expressed as: In addition, protein and water are treated as an albumin solution, and the albumin concentration and temperature are respectively C a (w / v%), T m(℃), T m is treated as the temperature of the subject. Considering the pigments contained in the body, oxygenated hemoglobin and deoxygenated hemoglobin, the concentration of each is C HbO (mM) and C Hb Expressed in (mM). From the above definition, the absorption coefficient μ a is expressed by the following equation (9).

[0044]

number

[0045] In equation (9), μ f represents the absorption coefficient of fat. Also, a0, a1, and a2 are the absorption coefficients of the albumin aqueous solution at albumin concentration C a and temperature T m is a coefficient for expressing the first-order polynomial. μ Hb and μ HbO are the absorption coefficients of oxygenated and deoxygenated hemoglobin, respectively.

[0046] Absorption coefficient μ when non-human animals such as pigs and chickens are used as test subjects a ' is the absorption coefficient μ expressed in equation (9) a can be expressed by the following equation (10), which adds the absorption coefficient of myoglobin pigment to

[0047]

number

[0048] In equation (10), μ MbO and μ Mb are the absorption coefficients of oxygenated and deoxygenated myoglobin, respectively. Also, C MbO and C Mb represent the concentrations (mM) of oxygenated and deoxygenated myoglobin, respectively.

[0049] In addition, the reduced scattering coefficient μ of the object required for the calculation of Equation (7) SAs ', the following equation (11) expressed as a function of wavelength λ is used.

[0050]

number

[0051] The theoretical value R^ of the reflectance is expressed by the following formula (12) using I^1 and I^2 obtained from formula (7).

[0052]

number

[0053] In addition, the theoretical value of the relative absorbance ratio γ^ k (k=1,…,m, where m=n-2) is the number of distinct n wavelengths λ i Theoretical reflectance R^ for (i=1,…,n) i can be calculated using the following formula (13).

[0054]

number

[0055] Theoretical value of relative absorbance ratio γ^ k In the calculation of f , albumin concentration C a , the temperature of the specimen T m (= temperature of the albumin solution), oxygenated hemoglobin concentration C HbO , deoxyhemoglobin concentration C Hb , oxygenated myoglobin concentration C MbO , deoxygenated myoglobin concentration C Mb The parameters P1 and P2 that determine the reduced scattering coefficient are treated as unknown parameters. These unknown parameters are all characteristic values ​​of the specimen, and the measured value of the relative absorbance ratio γ k The theoretical value of the relative absorbance ratio γ^ was calculated by the nonlinear least squares method. k is calculated under matching conditions. As the nonlinear least squares method, known analytical algorithms such as the Gauss-Newton method and the Levenberg-Marquardt method can be used. The temperature of the object can be measured separately using a measuring means such as a radiation thermometer. By making the temperature of the object known, the number of unknown parameters described above is reduced, and the estimation accuracy of other unknown parameters calculated by theoretical calculation is improved. In addition, the theoretical value of the relative absorbance ratio γ^ k The separation distances ρ1 and ρ2 and the boundary condition Ω required for the calculation are treated as known values, and the values ​​stored in advance in the data storage unit 34 are used. Furthermore, the absorption coefficient of fat μ f , coefficients a0, a1, a2 to express the absorption coefficient of the albumin aqueous solution as a first-order polynomial of albumin concentration and temperature, and the absorption coefficient μ of hemoglobin HbO and μ Hb and the absorption coefficient μ of myoglobin MbO and μ Mb are all treated as known, and the wavelength λ i As a function of the above, a value stored in advance in the data storage unit 34 is used.

[0056] In this embodiment, the probe end face 3a, the emission end face 4a, and the incidence end faces 5a and 6a are aligned on the same plane, so that the influence of light reflected from the object surface 2a can be reduced.

[0057] A modification of this embodiment will now be described. Fig. 5(a) is a side view of the light receiving section according to the first modified example, as viewed from the direction A in Fig. 1. Fig. 5(b) is a cross-sectional view taken along the line BB in Fig. 5(a). FIG. 6(a) is a side view of the light receiving section according to the second modified example as seen from the direction A, and FIG. 6(b) is a side view of the light receiving section according to the third modified example as seen from the direction A. The first to third modified examples include sensor probes 40, 41, and 42, respectively, instead of the sensor probe 3. Accordingly, the shapes and configurations of the optical fiber cables 5 and 6 are also changed.

[0058] 5, the optical fiber cables 5, 6 are made up of eight optical fibers 5b, 6b, each having an incident end face 5a, 6a (light receiving port) at one end and an exit end face 5c, 6c at the other end. The optical fiber cables 5, 6 are bundled together in a certain area with the exit end faces 5c, 6c aligned at the same position in the optical axis direction of the optical fibers, and are attached to the sensor probe 40 at one end so that the eight incident end faces 5a, 6a are spaced apart and positioned at their respective light receiving positions. The eight incident end faces 5a are arranged at equal intervals on a circle with a radius ρ1 from the center position (center of the light exit port) of the exit end face 4a, and are aligned on the same plane as the probe end face 40a. The eight incident end faces 6a are arranged at equal intervals on a circle with a radius ρ2 from the center position (center of the light exit port) of the exit end face 4a, and are aligned on the same plane as the probe end face 40a. Note that ρ2 > ρ1.

[0059] The circumferential position of the incident end faces 5a, 6a is not particularly limited, but in this embodiment, the incident end faces 5a, 5a and the incident end faces 6a, 6a, which are positioned opposite each other across the output end face 4a, are aligned in the same radial direction. That is, the incident end faces 5a and 6a have good symmetry on the probe end face 3a with respect to the exit end face 4a, and are arranged at equal intervals in the circumferential direction of the incident end faces 5a and 6a. As a result, the sensor probe 40 can uniformly receive light that has passed through the scattering body from a concentric measurement area centered on the exit end face 4a.

[0060] If the areas of the light receiving openings constituting the incident end faces 5a and 6a are the same in the circumferential direction, the wavelength λ i The total amount of light received J 1i , J 2i are calculated using the following formulas (14) and (15), respectively. J 1i =(I (1) 1i +I (2) 1i +…+I (8) 1i ) × A …(14) J 2i =(I (1) 2i +I (2) 2i +…+I (8) 2i ) × B … (15) In equations (14) and (15), A and B are the light receiving areas of the light receiving apertures of the incident end faces 5a and 6a, respectively. (k) 1i (k=1,2,…,8), I (k) 2i (k=1, 2, . . . , 8) represents the light intensity per unit area of ​​the reflected light received at each light receiving opening of the incident end faces 5a and 6a.

[0061] Next, the two different wavelengths λ appearing in Eq. (2) i , λ j (i≠j) reflectance ratio R i / R j is expressed by the following formula (16) based on the definition of formula (1). R i / R j =(J 2j ×J 1i ) / (J 1j ×J 2i ) …(16)

[0062] Using the relationship between equations (14) and (15), equation (16) can be expressed as the following equation (16a). R j / R i =(J 2j ×J 1i ) / (J 1j ×J 2i ) ={A×B×(I (1) 2j +I (2) 2j +…+I (8) 2j )×(I (1) 1i +I (2) 1i +…+I (8) 1i )} / {A×B×(I (1) 1j +I (2)1j +…+I (8) 1j )×(I (1) 2i +I (2) 2i +…+I (8) 2i )} ={(I (1) 2j +I (2) 2j +…+I (8) 2j )×(I (1) 1i +I (2) 1i +…+I (8) 1i )} / {(I (1) 1j +I (2) 1j +…+I (8) 1j )×(I (1) 2i +I (2) 2i +…+I (8) 2i )} …(16a)

[0063] The average light intensity per unit area at each light receiving opening of the incident end faces 5a and 6a is expressed by the following formulas (17) and (18), respectively.

[0064]

number

[0065]

number

[0066] By substituting equations (17) and (18) into equation (16a), the reflectance ratio expressed by equation (16) can be expressed as the following equation (16b).

[0067]

number

[0068] From equations (16a) and (16b), it can be seen that the reflectance ratio of two different wavelengths is expressed as the sum or average of the light intensities per unit area at the light receiving apertures of the incident end faces 5a and 6a, and is independent of the light receiving areas A and B. Therefore, by averaging and measuring the light reflected from the specimen 2, it is possible to average and measure the property characteristic value of the specimen 2, which is spatially non-uniform.

[0069] As shown in FIG. 6(a), a sensor probe 41 of the second modification has arc-shaped incident end faces 41a and 41b (light receiving apertures) that are aligned along the respective concentric circles, instead of the incident end faces 5a and 6a of the sensor probe 3. The incident end faces 41a, 41b may be formed by increasing the number of core wires of the optical fibers 5b, 6b and arranging them in an arc-shaped area, or may be formed from a light-guiding member having an arc-shaped cross-sectional shape to guide light to the optical fibers 5b, 6b. In this case, for example, by setting the circumferential lengths of the incident end faces 41a and 41b to be the same in proportion to the diameters of the respective concentric circles, the ratio of the light receiving areas in the circumferential direction can be made common, thereby making it possible to more even out the reflected light from inside the subject 2, which has spatially non-uniform scattering characteristics.

[0070] As shown in Fig. 6(b), a sensor probe 42 of the third modification has ring-shaped incident end faces 42a, 42b (light receiving ports) that open along the circumferential direction on respective concentric circles, instead of the incident end faces 5a, 6a of the sensor probe 3. The incident end faces 42a, 42b may be formed by increasing the number of core wires of the optical fibers 5b, 6b and arranging them circumferentially, or by combining multiple light-guiding members with arc-shaped cross sections. Furthermore, the incident end faces 42a, 42b may also be formed using a light-guiding member with a circular cross section shaped like a trumpet or megaphone. The sensor probe 42 can receive reflected light from inside the subject on all concentric circles, so it can reliably equalize the non-uniformity of transmitted light from the subject 2, regardless of any spatial non-uniformity in the property characteristic values.

[0071] A second embodiment of the present invention will be described with reference to Fig. 7. In the following description, components common to those already described will be assigned the same reference numerals and redundant description will be omitted.

[0072] FIG. 7 is a schematic diagram showing the general configuration of a nondestructive measuring device 100 according to this embodiment. 7, the nondestructive measuring device 100 includes a light source 51 and a coupling lens 9 instead of the light source 7. It also includes an optical fiber cable 4, a light source control unit 52, and a signal processing unit 70. The following description will focus on the differences from the first embodiment.

[0073] The light source 51 is a white light source that emits light in the near-infrared region, and may be a halogen lamp, etc. However, as long as the light source has a wavelength distribution that includes the wavelength light used for measurement, it may also be a light-emitting diode, and does not necessarily have to be a white light source.

[0074] The light source control unit 52 supplies voltage to the light source 51 in response to a control signal from the central control unit 18, and controls the light source 51 to light up at a predetermined light intensity. In this embodiment, since the light source emits white light, no control is performed to switch the wavelength.

[0075] The spectral detection units 61 and 62 shown in FIG. 7 split the outgoing light beams 11 and 12 emitted from the exit end faces 5c and 6c, and detect a total received light amount J of light beams of n wavelengths. 1i , J 2i (i=1, 2, ..., n) is acquired. That is, in this embodiment, the light intensity of light of multiple wavelengths is acquired by separating the reflected light received at the light receiving port. Therefore, even with one light source, light of multiple wavelengths can be easily acquired. To achieve this, the nondestructive measuring device 100 has diffraction gratings 53 and 54 and multi-channel detectors 55 and 56 .

[0076] The diffraction gratings 53 and 54 split the emitted light beams 11 and 12, respectively. The split wavelength range is n wavelengths λ i It is sufficient to obtain the above components. The multi-channel detectors 55 and 56 each have a large number of photodetector elements arranged at positions according to the diffraction angle on the optical path of the light diffracted by the diffraction gratings 53 and 54, and acquire the optical detection output of each to acquire the optical spectrum. As the multi-channel detectors 55 and 56, for example, a linear array sensor such as a CCD or CMOS can be used.

[0077] The measurement operation of the nondestructive measurement device 100 will be described, focusing on the differences from the first embodiment. As in the first embodiment, the sensor probe 3 is placed at the measurement site of the subject 2. When a command to start measurement is input from the operation unit 20, the central control unit 18 turns on the light source 51 via the light source control unit 52. White light having a wavelength range required for measurement is emitted as irradiation light 8, and is optically coupled to the incident end face 4c of the optical fiber 4b by a coupling lens 9. Furthermore, the light is irradiated from the exit end face 4a toward the object surface 2a.

[0078] The light irradiated onto the surface 2a of the subject 2 is scattered and absorbed by the internal properties of the subject 2 while passing through the interior of the subject 2, and part of the light that reaches the surface 2a of the subject again after passing through various optical paths is emitted to the outside of the subject 2 and enters the optical fibers 5b and 6b at the positions of the incident end faces 5a and 6a, respectively. At this time, the light that enters each optical fiber is scattered and absorbed for each wavelength according to the internal properties of the subject 2, and becomes light with a spectrum that contains information about the internal properties.

[0079] The emitted light beams 11 and 12 are separated by diffraction gratings 53 and 54 and received by multi-channel detectors 55 and 56. The spectroscopic detectors 61 and 62 send detection output signals proportional to the intensity of the received light to a signal processor 70.

[0080] The signal processing unit 70 operates the multichannel detectors 55, 56 for a predetermined exposure time and exposure timing, and converts the detection outputs of the multichannel detectors 55, 56 into reflection spectra S1, S2 that correspond to each channel and wavelength. Here, the reflection spectra S1, S2 are calibrated based on calibration information that is created in advance in accordance with the transmission loss of the optical fibers 5b, 6b, the reflectance of the diffraction gratings 53, 54, the wavelength sensitivity characteristics of each channel of the multichannel detectors 55, 56, etc. This allows the total received light amount J 1i , J 2i The calculated total amount of received light J 1i , J 2i is sent to the reflectance calculation unit 31.

[0081] The reflectance calculation unit 31 calculates the wavelength λ according to equation (1). i Reflectance R i and sends the calculation results to the relative absorbance ratio calculation unit 32. The relative absorbance ratio calculation unit 32 calculates m relative absorbance ratios γ k and sends it to the property characteristic value calculation unit 33. In the property characteristic value calculation unit 33, m relative absorbance ratios γ k (k=1,2,…,m) and its theoretical value γ^ k The property characteristic value is calculated using the nonlinear least squares method under the condition that the above conditions are met. The calculated property characteristic value is sent to the device control unit 21. The device control unit 21 controls the display control unit 22 to output the property characteristic value to the display unit 19. This completes the measurement of property characteristic values ​​by the nondestructive measuring device 100.

[0082] The nondestructive measuring device 100 according to this embodiment acquires a spectrum using the multi-channel detectors 55 and 56, calculates the light intensity for each wavelength received by the light receiving port, and finds the reflectance, eliminating the need to switch between irradiating light of different wavelengths. This makes it possible to simultaneously acquire the light intensity for multiple wavelengths in a short period of time, improving the accuracy and efficiency of measurements.

[0083] The following describes an example of measurement of biological tissue performed using a nondestructive measuring device according to a first modification of the first embodiment, which is equipped with the sensor probe 40. Chicken breast meat was used as the measurement object, and the separation distances ρ1 and ρ2 were set to 3 mm and 6 mm, respectively.

[0084] Figure 8(a) shows the measured reflectance R of the target tissue, which is expressed by Eq. (1). k The solid line in (b) of FIG. 8 shows the measured reflectance R k The measured value of the relative absorbance ratio γ calculated using equation (2) k This shows: Each point plotted in Figure 8(b) represents the theoretical value γ^ of the relative absorbance ratio at the corresponding wavelength calculated using equation (13). k and the theoretical value γ^ k is the measured value γ k The theoretical value γ^ k The calculation was performed at a pitch of 1 nm as described below, but the theoretical value γ^ k The measured value γ k To make it easier to distinguish from the theoretical value γ^ k are displayed at 5 nm pitch.

[0085] Theoretical value γ^ k In the calculation of the fat volume fraction k f , albumin concentration C a , oxygenated myoglobin concentration C MbO , deoxygenated myoglobin concentration C Mb was treated as a variable. Since the chicken meat was drained of blood, the oxygenated hemoglobin concentration C HbO and deoxyhemoglobin concentration C Hbwas set to 0. The temperature of the specimen T m The measured value was used as a known value. S ' is expressed by equation (11), with P1 and P2 as variables. From the above, the theoretical value of the relative absorbance ratio in this measurement is γ^ k There are a total of six property characteristic values ​​used as variables in the calculation.

[0086] n wavelengths λ i (i=1,2,...,n) n=281 wavelengths were selected in 1 nm steps from the range of 720 nm to 1000 nm. The wavelengths of the reflectances R1 and R2 appearing in equation (2) were λ1980 nm and λ21000 nm. The reflectances of the remaining wavelengths R3 to R 281 The measured value γ of m = 281-2 = 279 relative absorbance ratios using k and its theoretical value γ^ k The six types of property characteristic values ​​under the conditions that most closely approximate the above were calculated using the nonlinear least squares method and adopted as the measured values. The well-known Levenberg-Marquardt method was used as the nonlinear least squares method.

[0087] The fat volume fraction k measured at five locations in the target tissue using the above method f (%) and albumin concentration C a The estimated values ​​(w / v%) are shown in Table 1.

[0088] [Table 1]

[0089] Table 1 shows the k f and C a The estimated weight ratios of fat, moisture, and protein calculated based on the above are also shown. In addition, the actual weight ratios of fat, moisture, and protein are also shown, as determined by destroying the entire tissue after measurement and analyzing it using the specified methods: Soxhlet extraction for fat, atmospheric heating and drying for moisture, and combustion for protein (nitrogen / protein conversion factor = 6.25). The average error between the weight ratio estimated by the non-destructive measuring device and the actual weight ratio was 0.5 points for fat (maximum error 0.7 points), 0.8 points for moisture (maximum error 1.3 points), and 1.0 points for protein (maximum error 1.3 points). This measurement demonstrated that high measurement accuracy can be achieved without using a calibration curve.

[0090] In this example, the boundary condition Ω expressed by equation (9) is fixed at a value of 3.5 for chicken meat. However, the inventors have confirmed that similar measurement accuracy can be obtained regardless of the value of Ω as long as it is within the range of boundary conditions that can be assumed for animals such as pigs and chickens, and for humans, that is, within the range of Ω = 3.1 to 3.5. It has also been confirmed that measurements of other objects such as pork and milk can be performed with the same accuracy as the above example.

[0091] Another example procedure is to measure the temperature T m The fat volume fraction k obtained using the same procedure as above, while f , albumin concentration C a , and estimated weight ratios of fat, moisture, and protein are shown in Table 2.

[0092] [Table 2]

[0093] In Table 2, the average error between the weight ratio estimated by the non-destructive measuring device and the actual weight ratio was 1.2 points for fat (maximum error 1.5 points), 1.6 points for moisture (maximum error 2.5 points), and 2.7 points for protein (maximum error 4.1 points), which is a slight increase in the estimation error compared to Table 1. This is the temperature T m By making it unknown, the theoretical value of the relative absorbance ratio γ^ k This is thought to be due to the increase in variables required to calculate the ratio, but it was confirmed that this procedure still maintained sufficient accuracy for the estimated weight ratios of water and protein.

[0094] In the above measurement example, fitting using the relative absorbance ratio was performed, but in order to demonstrate the usefulness of the present invention, measurement results using other fitting methods are shown. Figure 9 shows the measured reflectance R k The theoretical value R^ shown by the dot k The fat volume fraction k obtained by this procedure is f , albumin concentration C a , and estimated weight ratios of fat, moisture, and protein are shown in Table 3.

[0095] [Table 3]

[0096] In Table 3, the average error between the weight ratio estimated by the non-destructive measuring device and the actual weight ratio was 0.8 points for fat (maximum error 1.5 points), 7.1 points for moisture (maximum error 12.2 points), and 7.8 points for protein (maximum error 13.8 points), which were even larger estimation errors than those in Table 2. In addition, the errors for protein and moisture were also large to an unacceptable level, and it was presumed that this method could not be applied to practical measurements.

[0097] The results shown in Tables 1 to 3 demonstrate that nondestructive measurement of light scattering materials can be performed with sufficient accuracy by fitting using the relative absorbance ratio without using a calibration curve, and that the temperature T m It was shown that sufficient accuracy can be maintained even when is unknown. This is a finding that was first revealed in the study of the present invention.

[0098] The nondestructive measuring device according to the present invention does not require a calibration curve and can therefore be suitably applied to the nondestructive measurement of tissues of various living organisms, including humans. For example, lymphedema occurs after surgery for malignant tumors due to lymph node dissection. This occurs because lymphatic fluid collection is no longer possible due to the loss of lymphatic gland function. However, by measuring body tissue with the nondestructive measuring device according to the present invention, increases in the absolute amounts of water and protein in tissue can be detected before edema becomes visible. This is expected to contribute to preventing lymphedema from becoming more severe by providing appropriate treatment at the early stage of edema onset.

[0099] In the present invention, in order to perform suitable fitting, the relative absorbance ratio γ k The two wavelengths λ1 and λ2 used to calculate the absorbance ratio γ k and the theoretical value γ^ k The number of pairs is important. The two wavelengths are not limited to 980 nm and 1000 nm in the above measurement example, and other combinations such as 810 nm and 980 nm are also possible.When this combination was used, the average error between the estimated weight ratio by the non-destructive measuring device and the actual weight ratio was 0.5 points for fat (maximum error 0.9 points), 0.5 points for moisture (maximum error 0.6 points), and 0.9 points for protein (maximum error 1.4 points). Relative absorbance ratio γ k and the theoretical value γ^ k Regarding the number of pairs, for example, the pitch is preferably 15 nm or less, but the relative absorbance ratio γ k and the theoretical value γ^ k The sets do not necessarily have to be evenly spaced.

[0100] Although each embodiment of the present invention has been described, the technical scope of the present invention is not limited to the above-described embodiments, and it is possible to change the combination of components, and to add various modifications to or delete each component, without departing from the spirit of the present invention. Some modifications are shown below as examples, but these are not all-inclusive and other modifications are also possible. Two or more of these modifications may be combined as appropriate.

[0101] In the above description, an example was given in which the probe end face that comes into contact with the non-analyte is flat, but the probe end face may also be curved to match the shape of the test object. The probe end face may also be made of a deformable, flexible material so that it can deform to match the shape of the test object when pressed against it. This makes it easier to place the light emitting and receiving ports close to the test object, which is expected to reduce measurement noise and improve measurement accuracy.

[0102] In the above explanation, an example was shown in which light from multiple light receiving ports on the same circumference is detected by one light detection unit, but the light from each light receiving port may be detected by a separate light detector, and the detection outputs may be processed by calculation, for example, by taking the sum or averaging. In each of the above-described embodiments, when the size of each light receiving opening is changed, the light receiving area becomes the sum of the opening areas that are uneven in the circumferential direction, so the I required to calculate the reflectance 1i , I 2i However, if the light from each light receiving port is detected by a separate photodetector, the size of each light receiving port in each light detection unit may be different. In other words, if the light from each light receiving port is detected by a separate photodetector, the light intensity normalized by the aperture area corresponding to each light receiving port is calculated, and the sum or average of these is taken, the I required to calculate the reflectance can be obtained. 1i , I 2i is obtained.

[0103] The relative absorbance ratio γ obtained based on the measured reflectance k The number m is the number n of wavelengths at which the maximum measured reflectance was obtained minus 2, as described above, but m does not necessarily have to be the maximum number. However, it goes without saying that the highest accuracy can be obtained by using the maximum number. [Explanation of symbols]

[0104] 1,100 Non-destructive measurement device for light scattering materials 2. Subject 3, 40, 41, 42 Sensor probe (fixed holding member) 4. Optical fiber cable (light irradiation part) 4a Output end face (light exit) 5, 6 Optical fiber cable (receiving part) 5a, 6a Input end face (light receiving aperture) 7 light source 30 Processing unit 41a, 41b, 42a, 42b Input end face (light receiving aperture) 50 Light detection unit

Claims

1. a light source that generates light of multiple wavelengths; a light irradiation unit having a light exit port for emitting the light beams of the plurality of wavelengths, and irradiating the light beams of the plurality of wavelengths from the light exit port toward one irradiation area on an object made of a light scattering medium; two light receiving units each having a light receiving opening at a position different from the center of the light exit opening, the two light receiving units receiving reflected light of the light of the plurality of wavelengths irradiated from the light exit opening and transmitted through the inside of the subject; a light detection unit that detects the light intensity of the light received by each of the light receiving units; a processor that calculates a reflectance, which is a ratio of the light intensities of the two light receiving units, for each of the plurality of wavelengths, and calculates a property characteristic value of the inside of the subject based on the reflectance; Equipped with The multiple wavelength lights include multiple wavelengths λ ｉ (i=1, 2, ..., n) light, The light detection unit is a unit of the two light receiving units, and the distance is ρ １ , ρ ２ (However, ρ １ <ρ ２ ) The wavelength λ of the reflected light received by the two light receiving parts ｉ The total amount of light received at each １ｉ , J ２ｉ When the detection is made as above, the calculation processing unit The wavelength λ is expressed by the following formula (1): ｉ Reflectance R ｉ Calculate The relative absorbance ratio γ expressed by the following formula (2) ｋ Calculate multiple The relative absorbance ratio γ ｋ The theoretical value γ^ of the relative absorbance ratio with the property characteristic value as a variable, corresponding to ｋ Get multiple The theoretical value γ ｋ and the relative absorbance ratio γ ｋ and outputting the property characteristic value under the condition that most closely matches the above. Non-destructive measurement device for light scattering materials. R ｉ \ ２ｉ / 4 １ｉ …(1) γ ｋ s(S ｋ＋２ 10 １ DR(S ２ 10 １ ) ...(2)

2. The calculation processing unit calculates the theoretical value γ̂ using a nonlinear least squares method. ｋ and the relative absorbance ratio γ ｋ Identify the conditions that most closely match The non-destructive measuring device for a light scattering medium according to claim 1 .

3. Further comprising a temperature detection unit for measuring the temperature of the subject; the calculation processing unit calculates the property characteristic value directly using the specimen temperature measured by the temperature detection unit. The non-destructive measuring device for a light scattering medium according to claim 1 .

4. an even number of the light receiving openings of the two light receiving units are provided at the distance, and are arranged to form pairs facing each other across the center of the light emitting opening; The non-destructive measuring device for a light scattering medium according to claim 1 .

5. a plurality of light receiving openings of the two light receiving units are provided at the distance, and are arranged at equal intervals on concentric circles centered on the light emitting openings; The non-destructive measuring device for a light scattering medium according to claim 1 .

6. Each of the light receiving openings of the two light receiving units has the same ring shape as a concentric circle centered on the light emitting opening or an arc shape that forms a part of the concentric circle. The non-destructive measuring device for a light scattering medium according to claim 1 .

7. a plurality of light receiving openings of the two light receiving units are provided at the distances; The light detection unit is configured to collectively detect light incident on the plurality of light receiving ports for each of the distances. The non-destructive measuring device for a light scattering medium according to claim 1 .

8. a plurality of light receiving openings of the two light receiving units are provided at the distances; the light detection unit is configured to detect light incident on each of the plurality of light receiving ports, and to calculate the light intensity at each of the light receiving ports, thereby detecting the light intensity for each of the light receiving ports. The non-destructive measuring device for a light scattering medium according to claim 1 .

9. an end portion of the light emitting portion on the light exit side and end portions of the two light receiving portions on the light receiving side are integrally held by a fixing holding member that fixes the distance therebetween; The non-destructive measuring device for a light scattering medium according to claim 1 .

10. a light emitting port of the light emitting unit and a light receiving port of the two light receiving units are aligned on the surface of the fixing and holding member or at a position in the vicinity thereof; The non-destructive measuring device for a light scattering medium according to claim 9.

11. the surface of the fixing and holding member on which the light exit port of the light irradiation unit and the light receiving ports of the two light receiving units are located has light absorption properties; The non-destructive measuring device for a light scattering medium according to claim 10.

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