Optical measurement device, optical measurement system, optical measurement method, and optical measurement program

Abstract

A light emission control unit (320) of an optical measurement device (10) prepares a first orthogonal code, prepares a first mixed light composed of mixing a plurality of wavelengths of lights, and causes a light emitting device (100) to emit an emitted light (110), which includes the first mixed light with a first emission intensity and a first emission time pattern, onto a detection target (410). A signal processing unit (310) of the optical measurement device (10) accepts a first detected intensity of a light of a first detection wavelength generated by emission of the emitted light (110), and performs a first processing for calculating the first intensity of the light of the first detection wavelength generated by emission of the first mixed light on the basis of the first detected intensity and a first orthogonal code.

Description

Optical measurement device, optical measurement system, optical measurement method, and optical measurement program

[0001] The present disclosure relates to an optical measurement device, an optical measurement system, an optical measurement method, and an optical measurement program.

[0002] There has been proposed a device that identifies the type of substance contained in a detection target by irradiating the target with irradiation light composed of multiple laser beams of different wavelength bands, receiving an optical signal as light generated from the detection target, and identifying the optical signal (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2005-233648

[0004] In the above-described conventional device, when acquiring the generated light, which is a response to the irradiated light necessary for identifying the type of substance contained in the detection target, it is necessary to prepare the same number of orthogonal codes as the number of irradiated lights and measure the generated light. However, in order to increase the number of usable orthogonal codes, the code length of the orthogonal codes needs to be increased, which poses a problem in that the longer the code length, the longer the time required to measure the generated light for each irradiated light.

[0005] The present disclosure aims to provide an optical measurement device, an optical measurement system, an optical measurement method, and an optical measurement program that enable measurement, in a short period of time, of light generated from a detection object irradiated with irradiation light.

[0006] The optical measurement device disclosed herein includes a light irradiation control unit that controls a light irradiation device that irradiates a detection object with irradiation light, and a signal processing unit that receives a detection signal output from a light detection device that detects generated light obtained from the detection object irradiated with the irradiation light, wherein the light irradiation control unit prepares a first orthogonal code having a code length W when an integer equal to or greater than 2 is represented by W, and prepares first mixed light that is composed of M wavelengths of light mixed at a first irradiation intensity ratio when the integer equal to or greater than 2 is represented by M, and causes the light irradiation device to irradiate the detection object with the irradiation light that includes the first mixed light having a first irradiation intensity and a first irradiation time pattern corresponding to the first orthogonal code, and the signal processing unit receives a first detection intensity of light of a first detection wavelength generated by irradiation with the irradiation light as the detection signal, and performs a first process that calculates a first intensity of light of the first detection wavelength generated by irradiating the first mixed light based on the first detection intensity and the first orthogonal code.

[0007] The optical measurement method disclosed herein is a method executed by an optical measurement device that controls a light irradiation device that irradiates a detection object with irradiation light and receives a detection signal output from a light detection device that detects generated light obtained from the detection object irradiated with the irradiation light, the method comprising: preparing a first orthogonal code having a code length W, where W is an integer equal to or greater than 2; preparing a first mixed light that is composed of M wavelengths of light mixed at a first irradiation intensity ratio, where M is an integer equal to or greater than 2; irradiating the detection object with the irradiation light from the light irradiation device, the first mixed light having a first irradiation intensity and a first irradiation time pattern corresponding to the first orthogonal code; receiving a first detection intensity of light of a first detection wavelength generated by irradiation with the irradiation light as the detection signal; and performing a first process of calculating a first intensity of light of the first detection wavelength generated by irradiation with the first mixed light based on the first detection intensity and the first orthogonal code.

[0008] By using the optical measurement device, optical measurement system, optical measurement method, and optical measurement program disclosed herein, it is possible to measure, in a short time, light generated from a detection target irradiated with irradiation light.

[0009] 1 is a diagram schematically illustrating a configuration of an optical measurement system (including an optical measurement device) according to a first embodiment. FIG. 2 is a diagram illustrating an example of a hardware configuration of the optical measurement system according to the first embodiment. FIG. 3 is a diagram illustrating an orthogonal code having a code length of "4" used in the optical measurement system according to the first embodiment. FIG. 4 is an explanatory diagram illustrating first mixed light (i.e., combined light formed by mixing light of multiple wavelengths at a first irradiation intensity ratio) and second mixed light (i.e., combined light formed by mixing light of multiple wavelengths at a second irradiation intensity ratio) used in the optical measurement system according to the first embodiment. FIG. 5 is a diagram illustrating the irradiation intensity and irradiation time pattern of the first mixed light (corresponding to the orthogonal code having a code length of "4") and the irradiation intensity and irradiation time pattern of the second mixed light (corresponding to another orthogonal code having a code length of "4") used in the optical measurement system according to the first embodiment. FIG. 6 is a diagram illustrating the irradiation intensity and irradiation time pattern of irradiation light composed of the first mixed light and the second mixed light used in the optical measurement system according to the first embodiment. 1 is a diagram showing the detection intensity of first generated light (i.e., light of the first detection wavelength generated in response to the first mixed light and light of the first detection wavelength generated in response to the second mixed light) detected by the optical measurement system according to the first embodiment. FIG. 2 is a diagram showing the detection intensity of second generated light (i.e., light of the second detection wavelength generated in response to the first mixed light and light of the second detection wavelength generated in response to the second mixed light) detected by the optical measurement system according to the first embodiment. FIG. 3 is a diagram showing a measurement process (i.e., a process of calculating the detection intensity of light of the first detection wavelength generated by irradiation with the first mixed light) performed by the optical measurement system according to the first embodiment. FIG. 4 is a diagram showing a measurement process (i.e., a process of calculating the detection intensity of light of the second detection wavelength generated by irradiation with the second mixed light) performed by the optical measurement system according to the first embodiment. FIG. 5 is a flowchart showing an example of the measurement process performed by the optical measurement system according to the first embodiment. FIG. 6 is a diagram showing an outline of the configuration of an optical measurement system (including an optical measurement device) of the comparative example. FIG. 7 is a diagram showing an orthogonal code with a code length of "8" used in the optical measurement system of the comparative example. FIG. 8 is a diagram showing the irradiation intensity and irradiation time pattern of light of each wavelength used in the optical measurement system of the comparative example.15A and 15B are diagrams showing the irradiation intensity of mixed light (i.e., combined light formed by mixing light of a plurality of wavelengths at a predetermined irradiation intensity ratio) used in an optical measurement system of a comparative example. FIG. 16A is a diagram showing the detection intensity of first generated light (i.e., light of a first detection wavelength generated in response to the mixed light of FIG. 15A) detected by the optical measurement system of a comparative example. FIG. 16B is a diagram showing the detection intensity of second generated light (i.e., light of a second detection wavelength generated in response to the mixed light of FIG. 15A) detected by the optical measurement system of a comparative example. FIG. 16C is a diagram showing a measurement process (i.e., a process of calculating, from light of the first detection wavelength, the detection intensity of a detection wavelength component corresponding to an irradiation time pattern of a code length "8") performed by the optical measurement system of a comparative example. FIG. 16D is a diagram showing the configuration of an optical measurement system (including an optical measurement device) according to a second embodiment. FIG. 16E is a diagram showing the configuration of an optical measurement system (including an optical measurement device) according to a third embodiment.

[0010] An optical measurement device, an optical measurement system, an optical measurement method, and an optical measurement program according to embodiments will be described below with reference to the drawings. The following embodiments are merely examples, and the embodiments can be combined as appropriate and each embodiment can be modified as appropriate.

[0011] The optical measurement device according to the embodiment includes a light irradiation control unit that prepares one or more mixed lights, which are combinations of light obtained by mixing light of multiple wavelengths at predetermined irradiation intensities, and controls the light irradiation device to modulate the combinations of light using irradiation time patterns of different orthogonal codes and irradiate them simultaneously, and a signal processing unit that receives detection signals output from a light detection device that detects light generated from a detection object irradiated with irradiation light, and based on the irradiation time patterns of the orthogonal codes, the signal processing unit individually extracts the intensities of light generated when the combinations of light modulated by the irradiation time patterns of each orthogonal code are irradiated from the detection signals of light for each wavelength detected by the light detection device, and estimates the quantity or presence or absence of the detection object using the intensities of light as a feature.

[0012] In addition, the optical measurement device according to the embodiment further includes a data set consisting of a measurement data set relating to the intensity of light of each wavelength detected by the signal processing unit when each of the light of the plurality of wavelengths previously acquired is irradiated onto the detection object, and a corresponding correct data set of the amount of the detection object, and the signal processing unit determines the predetermined irradiation intensity of each of the light of the plurality of wavelengths irradiated by the light irradiation device based on the data set.

[0013] <<1>> Embodiment 1 <<1-1>> Configuration Fig. 1 is a diagram schematically illustrating the configuration of an optical measurement system 1 (including an optical measurement device 10) according to embodiment 1. The optical measurement system 1 includes a light irradiation device 100 that irradiates a detection target 410 as an object with irradiation light 110, a light detection device 200 that detects generated light 120 obtained from the detection target 410 irradiated with the irradiation light 110, and the optical measurement device 10. The detection target 410 is, for example, a substance attached to the surface of a member 400 (e.g., an attachment such as dirt), a substance constituting the member 400 (e.g., a material, a component), or the like.

[0014] The optical measurement device 10 can measure the amount of the detection target 410 or determine the presence or absence of the detection target 410 based on the relationship between the wavelength λ of light irradiated onto the detection target 410 and the detection wavelength λ' of light obtained from the detection target 410 in response to the irradiation of light of wavelength λ. The optical measurement device 10 has a light irradiation control unit 320 that controls the light irradiation device 100, and a signal processing unit 310 that receives a detection signal output from the light detection device 200. The optical measurement device 10 is a device that can implement the optical measurement method according to the first embodiment. The optical measurement device 10 is, for example, a computer. The optical measurement device 10 may be a computer system configured by cloud computing using a computer network.

[0015] The light irradiation device 100 has a light source for irradiating the detection target 410 with irradiation light 110 composed of light of multiple wavelengths. Examples of light sources that can be used include multiple light-emitting diodes (LEDs), multiple semiconductor lasers, and the like. The light of multiple wavelengths includes any of visible light, infrared light, ultraviolet light, and terahertz waves. The light of multiple wavelengths may include two or more types of light among visible light, infrared light, ultraviolet light, and terahertz waves (e.g., visible light and infrared light, visible light and ultraviolet light, visible light, infrared light and ultraviolet light, visible light, infrared light and terahertz waves, etc.).

[0016] The photodetector 200 is a device capable of detecting the intensity of light at one or more predetermined detection wavelengths. The photodetector 200 is, for example, a device that can integrate light in a predetermined wavelength band and detect it as a single signal, like a monochrome camera. The photodetector 200 may also be a device that can individually detect light in multiple wavelength bands, like a color camera. The photodetector 200 may also be a device that separates light at multiple wavelengths and detects the light at each separated wavelength, like a spectroscope.

[0017] The light irradiation control unit 320 calculates an orthogonal code C having a code length W, where t represents time and W represents an integer equal to or greater than 2. １ (t) and an orthogonal code C having a code length W ２ The code length W is, for example, 4, but is not limited to 4. The orthogonal code C １ (t) and orthogonal code C ２ (t) are mutually different orthogonal codes. When M is a positive integer, the light irradiation control unit 320 determines M wavelengths λ １ , …, λ Ｍ a combined light (i.e., a first mixed light) formed by mixing the light of M wavelengths λ １ , …, λ Ｍ and a combined light (i.e., second mixed light) composed by mixing the light of (I) at a second irradiation intensity ratio. The number of wavelengths of light constituting the second mixed light may be other than M. Furthermore, the number of mixed lights used may be three or more.

[0018] In the first embodiment, the wavelength λ １ , …, λ Ｍ is predetermined, the first irradiation intensity ratio is predetermined, and the second irradiation intensity ratio is predetermined. That is, the first mixed light is composed of M wavelengths λ １ , …, λ Ｍ The second mixed light is a combined light formed by combining light of a plurality of wavelengths selected from light of M wavelengths λ at a predetermined first irradiation intensity ratio, and has a code length W. In the first embodiment, the second mixed light is a light of M wavelengths λ １ , …, λ Ｍ The orthogonal code is a combined light beam formed by combining light beams of a plurality of wavelengths selected from the light beams of (1) and (2) at a predetermined second irradiation intensity ratio, and has a code length W. The orthogonal code will be described in detail later with reference to FIG. 3. The first mixed light beam and the second mixed light beam will be described in detail later with reference to FIG. 4.

[0019] The light irradiation control unit 320 receives the first irradiation intensity and the orthogonal code C １ a first mixed light having a first irradiation time pattern corresponding to (t), and a second irradiation intensity and an orthogonal code C ２ The light irradiation control unit 320 irradiates the detection target 410 with irradiation light 110 including the first mixed light and second mixed light having a second irradiation time pattern corresponding to (t). The light irradiation control unit 320 irradiates the detection target 410 with the first mixed light and the second mixed light as the irradiation light 110 such that the first irradiation time pattern and the second irradiation time pattern overlap in time. The irradiation light 110 will be described in detail later with reference to FIGS. 5 and 6. The irradiation light 110 may also include three or more types of mixed light.

[0020] The signal processing unit 310 detects the first detection wavelength λ′ generated by irradiation with the irradiation light 110 as a detection signal. １ The first detected intensity L of light (t) １ (t) and the first detected intensity L １ (t) and orthogonal code C １ (t) (e.g., orthogonal code C １ (t)) and the first detection wavelength λ′ generated by irradiation with the first mixed light based on the Walsh code (t) １ (t) light intensity (first intensity) L１，１ (t) (first process), and the first detection intensity L １ (t) and orthogonal code C ２ (t) (e.g., orthogonal code C ２ (t)) and the first detection wavelength λ′ generated by irradiation with the second mixed light based on the Walsh code (t) １ (t) light intensity (second intensity) L １，２ and a process (second process) for calculating the first detection wavelength λ′ (t) for each of the first mixed light and the second mixed light (i.e., one or both of them). １ The calculation of the detected intensity of light (t) will be explained in detail later with reference to FIGS.

[0021] Furthermore, the signal processing unit 310 detects a first detection wavelength λ′ generated by irradiation with the irradiation light 110 as a detection signal. １ A second detection wavelength λ′ different from (t) ２ The second detected intensity L of light (t) ２ (t) and the second detection intensity L ２ (t) and orthogonal code C １ (t) (e.g., orthogonal code C １ (t)) and the Walsh code that is the basis of (t), ２ (t) light intensity (third intensity) L ２，１ (t) (third process), and the second detection intensity L ２ (t) and orthogonal code C ２ (t) (e.g., orthogonal code C ２ (t)) and the second detection wavelength λ′ generated by irradiation with the second mixed light based on the Walsh code (t) ２ (t) light intensity (fourth intensity) L ２，２ and a fourth process (fourth process) for calculating the second detection wavelength λ′ (t). ２ The calculation of the detected intensity of light (t) will be explained in detail later with reference to FIGS.

[0022] 2 is a diagram showing an example of the hardware configuration of the optical measurement system 1 according to the first embodiment. The optical measurement system 1 includes a light irradiation device 100, a light detection device 200, and an optical measurement device 10. The optical measurement device 10 includes a processor 11 such as a CPU (Central Processing Unit), a memory 12 as a storage device such as a RAM (Random Access Memory), a storage device 13 as a non-volatile storage device such as an HDD (Hard Disk Drive) or an SSD (Solid State Drive), and an interface 14. These components may be configured using a dedicated processing circuit such as a system LSI (Large-Scale Integration). In the light irradiation device 100, multiple processors and multiple memories may work together to achieve desired functions.

[0023] The processor 11 can execute the optical measurement program according to the first embodiment stored in the memory 12. The optical measurement program is provided to the optical measurement device 10 by being recorded on a recording medium such as an SD memory card (Secure Digital memory card) or a USB (Universal Serial Bus) memory card, or by being downloaded via a network. The hardware configuration shown in Fig. 2 is an example, and various modifications to the hardware configuration are possible.

[0024] <<1-2>> Operation <<1-2-1>> Light Irradiation Device 100> The light irradiation device 100 prepares two or more combinations of light (i.e., mixed light) in which light of multiple wavelengths is mixed at predetermined irradiation intensities, modulates the combinations of light using irradiation time patterns of orthogonal codes that are different from each other, and simultaneously irradiates them as irradiation light 110. However, the number N of light combinations may be 1. In this case, for example, the code length W of the orthogonal code may be set to 2, and W-1 types, i.e., 1 type of orthogonal code, may be obtained.

[0025] FIG. 3 shows the orthogonal code C with a code length of “4” used in the optical measurement system 1 according to the first embodiment. １ (t) and the orthogonal code C of code length “4” ２ FIG.

[0026] The optical measurement device 10 generates an orthogonal code C that modulates the irradiated light composed of the first light combination (i.e., mixed light) to the Nth light combination (N is a positive integer). １ (t), ..., C Ｎ (t) is used. Orthogonal code C １ (t), ..., C Ｎ (t) is a time series consisting of 1s and 0s and having a code length W (W is an integer equal to or greater than 2) which is the length of the orthogonal code. ｎ１ (t) and C ｎ２ An example will be described in which (t) satisfies the formulas (1.1), (1.2), and (1.3), where n1 and n2 are positive integers, and n1≠n2.

[0027]

[0028] As shown in equation (1.1), the same orthogonal code C ｎ１ The sum of the inner products of (t) is W / 2. As shown in equation (1.2), ｎ１ (t) and C ｎ２ The sum of the inner products of (t) is W / 4. In other words, in the first embodiment, each of the first orthogonal codes and the second orthogonal codes is configured by an array of combinations of 1s and 0s, and this array contains the same number of 1s and 0s. Furthermore, the inner product between two first orthogonal codes is equal to the inner product between two second orthogonal codes, and the inner product between the first orthogonal codes and the second orthogonal codes is half of the inner product between two first orthogonal codes.

[0029] The orthogonal codes used in the first embodiment can be created using Walsh codes, which are code sequences having a code length W and consisting of 1 or -1. First, there are W types of Walsh codes with a code length W. Of the W types of Walsh codes, Walsh codes consisting entirely of 1 are excluded, and W-1 types of Walsh codes are extracted. Next, by replacing -1 in these Walsh codes with 0, W-1 types of orthogonal codes, which are code sequences consisting of 1 or 0 and satisfy equations (1.1), (1.2), and (1.3), are obtained.

[0030] FIG. 4 shows the first mixed light (for example, a plurality of wavelengths λ ) used in the optical measurement system 1 according to the first embodiment. １ , …, λ ７ , E17) and a second mixed light (for example, a plurality of wavelengths λ １ , …, λ ７ 10 is an explanatory diagram showing a combination of light obtained by mixing the light of the first embodiment with the light of the second embodiment at a second irradiation intensity ratio E21, . . . , E27.

[0031] The irradiating light 110 has M wavelengths λ １ , …, λ Ｍ Each light has a wavelength λ １ , …, λ Ｍ The mixed light (there are N of them) is a combination of light summed with a predetermined weight. １ (t), ..., C Ｎ (t) includes light obtained by modulating the light irradiated by the light irradiating device 100. In the first embodiment, the number of combined light beams (i.e., the number of mixed light beams) is set to match the number of wavelengths of light detected by the light detecting device 200 (i.e., the number of detected wavelengths). Note that the number of combined light beams (i.e., the number of mixed light beams) constituting the irradiation light 110 irradiated by the light irradiating device 100 may be different from the number of wavelengths of light detected by the light detecting device 200 (i.e., the number of detected wavelengths).

[0032] Next, for each wavelength λ from the first light combination (i.e., mixed light) to the Nth light combination (i.e., mixed light), １ , …, λ Ｍ The weights are expressed as follows:

[0033] For example, if n is an integer between 1 and N, then each wavelength λ for the n-th combination of light １ , …, λ Ｍ The weight of ("weight x ｎ ") is expressed by the following equation (1.4).

[0034]

[0035] On the right side of equation (1.4), x ｎ，ｍ(m is an integer between 1 and M), the wavelength λ for the nth light combination ｍ The superscript "T" denotes transposition. In the illuminating light 110, the wavelength λ １ , …, λ Ｍ The irradiation intensity of the light combination at time t ("irradiation intensity I １ (t), ..., I Ｎ (t)") is expressed as follows:

[0036]

[0037] At this time, the irradiation intensity of the n-th light combination at time t ("irradiation intensity I ｎ (t)") is expressed by the following equation (1.5).

[0038]

[0039] From the above, the irradiation intensity of the irradiation light 110 at time t (also referred to as "irradiation intensity I(t)") is expressed by the following equation (1.6).

[0040]

[0041] <<1-2-2>> Photodetector 200 The operation of the photodetector 200 will be described. First, for the detection target 410, each wavelength λ of unit intensity is １ , …, λ Ｍ Each detection wavelength λ' generated when light of １ , …, λ´ Ｎ The detected intensity of the generated light 120 ("detected intensity q １ , …, q Ｎ ") is written as follows:

[0042]

[0043] At this time, each wavelength λ of unit intensity for the detection target 410 １ , …, λ Ｍ The detection wavelength λ' generated when light of ｎ The detected intensity of the generated light 120 ("detected intensity q ｎ´ ") is expressed by the following equation (1.7).

[0044]

[0045] In formula (1.7), q ｎ´，ｍ is the wavelength λ of unit intensity for the detection target 410. ｍ The detection wavelength λ' generated when light of ｎ is the intensity of the generated light 120 at time t. The detected wavelengths λ′ at time t are generated by the first light combination (i.e., mixed light) to the Nth light combination (i.e., mixed light) of the irradiation light 110. １ , …, λ´ Ｎ The detected intensity of the generated light 120 is expressed as follows:

[0046]

[0047] Detection intensity L ｎ´，ｎ The first subscript "n'" in (t) designates the detection wavelength of the generated light 120 to be detected, and the second subscript "n" designates the detection intensity L ｎ´，ｎ The nth light combination (i.e., mixed light) contributes to (t). In this case, the detected wavelength λ generated by the nth light combination is ｎ´ The detected intensity L of the generated light 120 at time t ｎ´，ｎ (t) is expressed by the following equation (1.8).

[0048]

[0049] Detection wavelength λ′ detected by the photodetector 200 １ , …, λ´ Ｎ The detected intensity L of the generated light 120 at time t １ (t), ..., L Ｎ Here, the detection wavelength λ′ detected by the photodetector 200 will be described. ｎ´ The detected intensity L of the generated light 120 at time t ｎ´ (t) is expressed by the following equation (1.9).

[0050]

[0051] In formula (1.9), α ｎ´ is the wavelength λ ｎ´This is DC noise (i.e., background noise) caused by ambient light or the like in the signal.

[0052] <<1-2-3>> Signal Processing Unit 310 The signal processing unit 310 processes the orthogonal code C １ (t), ..., C Ｎ The restored signal D calculated based on (t) １ (t), ..., D Ｎ (t) is used. Orthogonal code C ｎ The restored signal D calculated based on (t) ｎ An example of (t) is shown in the following equation (1.10).

[0053]

[0054] At this time, the orthogonal code C ｎ１ (t), the restored signal D ｎ１ (t) has the property shown in the following equation (1.11).

[0055]

[0056] In addition, the orthogonal code C ｎ１ (t), the restored signal D ｎ２ (t) has the property shown in the following equation (1.12).

[0057]

[0058] In addition, the restored signal D ｎ１ (t) has the property shown in the following equation (1.13).

[0059]

[0060] Next, the detection intensity L １ (t), ..., L Ｎ In (t) The restored signal D １ (t), ..., D Ｎ A method of extraction using (t) will be explained.

[0061] Detection intensity L ｎ´ In (t) is the restored signal D ｎ´ (t) is used to calculate as shown in the following formula (1.14).

[0062]

[0063] Here, the detection intensity L １ (t), ..., L Ｎ Since (t) is modulated by the irradiation time patterns of the orthogonal codes, the respective irradiation time patterns are strictly orthogonal.

[0064] That is, as shown in equation (1.14), are strictly separable.

[0065] In other words, When calculating the DC component α ｎ´ The background noise, which is the signal, can be precisely removed.

[0066] next, is used as a feature quantity, an estimate of the quantity of the detection object 410 (also written as "estimate y^") is calculated as shown in the following equation (1.15).

[0067]

[0068] In formula (1.15), t ｎ´ teeth, is the value multiplied by the feature is a value that adjusts the contribution of each of

[0069] The signal processing unit 310 may estimate the presence or absence of the detection target 410 based on the value of the estimated amount y^. Alternatively, the signal processing unit 310 may classify the adhesion amount of the detection target 410 according to a classification corresponding to the adhesion amount (e.g., class 1, class 2, class 3, etc.).

[0070] Next, as an example, the operation will be described when the number of wavelengths M of the irradiated light 110 is set to 7, and the number of light combinations and detected wavelengths N is set to 2. However, N is not limited to 2. N may be 1, or may be a value of 3 or more. The wavelength λ irradiated by the light irradiation device 100 １ , …, λ ７ the magnitude of the irradiation intensity of the combined light (i.e., the first mixed light) composed of the light of the first mixed light and the other combined light (i.e., the second mixed light) ("x １ ", "x ２") are shown in the following equations (1.16) and (1.17).

[0071]

[0072] Fig. 5 is a diagram showing the irradiation intensity and irradiation time pattern of the first mixed light (corresponding to the orthogonal code with a code length of "4") and the irradiation intensity and irradiation time pattern of the second mixed light (corresponding to another orthogonal code with a code length of "4") used in the optical measurement system 1 according to embodiment 1. Fig. 6 is a diagram showing the irradiation intensity and irradiation time pattern of the irradiation light 110 composed of the first mixed light and the second mixed light used in the optical measurement system 1 according to embodiment 1.

[0073] As shown in FIGS. 5 and 6, the light irradiation device 100 generates a combined light (i.e., first mixed light) consisting of the light shown in formulas (1.18) and (1.19) and adjusts the irradiation intensity of the combined light (i.e., second mixed light). (“Irradiation intensity I １ (t)”, “irradiation intensity I ２ (t)" (also written as "(t)")) is added together to obtain the irradiation intensity shown in equation (1.20). (also referred to as "irradiation intensity I(t)") is irradiated.

[0074]

[0075] In the first embodiment, the orthogonal code C １ (t), C ２ As (t), an orthogonal code with a code length of "4" shown in FIG. 3, which is created based on the Walsh code, is used.

[0076] Next, for each wavelength λ of unit intensity for the detection target 410 １ , …, λ ７ The detection wavelength λ' generated when light of １ The detected intensity of the generated light 120 ("Detection intensity q １ ") and the detection wavelength λ' ２ The detected intensity of the generated light 120 ("Detection intensity q ２ ") are shown in the following equations (1.21) and (1.22), respectively.

[0077]

[0078] FIG. 7 shows the first generated light (i.e., the first detected wavelength λ′ generated in response to the first mixed light) detected by the optical measurement device 10. １ and the second mixed light. １ The detected intensity L １ 8 is a diagram showing the second generated light (i.e., the second detected wavelength λ′ generated in response to the first mixed light) detected by the optical measurement device 10. ２ and the second mixed light. ２ The detected intensity L ２ FIG.

[0079] Also, the detection wavelength λ′ generated by the first mixed light, which is the combined light, １ The detected intensity L of the generated light 120 １，１ (t) and the detection wavelength λ′ generated by the second mixed light, which is the combined light. １ The detected intensity L of the generated light 120 １，２ (t) and the detection wavelength λ′ generated by the first mixed light ２ The detected intensity L of the generated light 120 ２，１ (t) and the detection wavelength λ′ generated by the second mixed light ２ The detected intensity L of the generated light 120 ２，２ (t) are shown in the following equations (1.23) to (1.26).

[0080]

[0081] Detection wavelength λ′ detected by the photodetector 200 １ Detection intensity L １ (t) and the detection wavelength λ' ２ Detection intensity L ２ (t) are shown in the following equations (1.27) and (1.28).

[0082]

[0083] 9 is a diagram showing a measurement process (i.e., a process of calculating the detection intensity of light of a first detection wavelength generated by irradiation with a first mixed light) executed by the optical measurement system 1 according to the first embodiment. FIG. 10 is a diagram showing a measurement process (i.e., a process of calculating the detection intensity of light of a second detection wavelength generated by irradiation with a second mixed light) executed by the optical measurement system according to the first embodiment. As shown in FIGS. 9 and 10 , the following feature quantities are calculated: is calculated using equations (1.29) and (1.30).

[0084]

[0085] Next, an estimated amount y^ of the amount of the detection target 410 is calculated by the following equation (1.31).

[0086] 11 is a flowchart showing an example of a measurement process executed by the optical measurement system 1. First, the optical measurement device 10 of the optical measurement system 1 generates two or more orthogonal codes having a code length W (C in FIG. 3) when an integer of 2 or more is represented by W. １ (t), C ２ (t)) is prepared (step S1). However, the number of orthogonal codes to be prepared may be one. １ , …, λ Ｍ a first mixed light (FIG. 6) composed by mixing the light of wavelength λ １ , …, λ Ｍ The first light and the second light are mixed at a second irradiation intensity ratio to prepare a second mixed light (FIG. 6) (step S2). However, the number of mixed lights to be prepared may be one.

[0087] Next, the optical measurement device 10 receives a first irradiation intensity and an orthogonal code (C in FIG. 3) from the light irradiation device 100. １ a first mixed light (FIG. 5) having a first irradiation time pattern corresponding to the first irradiation intensity (I in FIG. 5) and a second irradiation intensity (I in FIG. 5) ２ (t)) and orthogonal code (C in FIG. 3 ２The target 410 is irradiated with irradiation light 110 (FIG. 6) including the first mixed light and the second mixed light (FIG. 5) having a second irradiation time pattern corresponding to the first mixed light (t) (step S3). However, the irradiation light 110 may include only one of the first mixed light and the second mixed light.

[0088] The optical measurement device 10 detects a first detection wavelength (λ' in FIG. 7) generated by irradiation with the irradiation light 110 as a detection signal from the photodetector 200. １ The first detected intensity of light (L in FIG. 7) １ The optical measurement device 10 also receives the second detection wavelength (λ' in FIG. 8) generated by the irradiation of the irradiation light 110 as a detection signal from the light detection device 200 (step S4). ２ (t)) of the second detected intensity of light (L in FIG. 8 ２ (t)) is received (step S4).

[0089] The optical measurement device 10 detects a first detected intensity (L １ (t)) and an orthogonal code (more specifically, an orthogonal code C １ The restored signal D corresponding to (t) １ (t)) and a first detection wavelength (λ') generated by irradiation with the first mixed light. １ (t)) light intensity (L １，１ (t)) and a first process of calculating a first detection intensity (L １ (t)) and an orthogonal code (more specifically, an orthogonal code C ２ The restored signal D corresponding to (t) ２ (t)) and the first detection wavelength (λ') generated by irradiation with the second mixed light. １ (t)) light intensity (L １，２ and a second process of calculating (t) (step S5).

[0090] In addition, the optical measurement device 10 detects a second detected intensity (L ２ (t)) and an orthogonal code (more specifically, an orthogonal code C １ The restored signal D corresponding to (t) ２ (t)) and a first detection wavelength (λ') generated by irradiation with the first mixed light. １ (t)) light intensity (L ２，１(t)) and a third process of calculating the first detection intensity (L １ (t)) and an orthogonal code (more specifically, an orthogonal code C ２ The restored signal D corresponding to (t) ２ (t)) and the second detection wavelength (λ') generated by irradiation with the second mixed light. ２ (t)) light intensity (L ２，２ and a fourth process of calculating (t) (step S5).

[0091] When performing the first processing, the signal processing unit 310 detects a first detection intensity (L １ (t)) and the orthogonal code (C １ The first recovered signal (D １ (t)) １ (t) L １ (t)) (FIG. 9), the first characteristic amount is acquired, the amount of the detection target 410 is calculated based on the first characteristic amount, and when the second processing is performed, the first detection intensity (L １ By multiplying the second restored signal (t) by the orthogonal code, which is a Walsh code corresponding to the orthogonal code, and performing time integration of the function obtained, a second feature amount is obtained, and the amount of the detection target 410 can be calculated based on the second feature amount.

[0092] Furthermore, when the third processing is performed, the signal processing unit 310 detects the second detection intensity L ２ (t), orthogonal code C １ (t) by the first restored signal, which is the Walsh code corresponding to (t), and then time-integrating the function obtained, a third feature amount is acquired, and the amount of the detection object 410 is calculated based on the third feature amount. When performing the fourth process, the second detection intensity (L ２ (t)) and the orthogonal code (C ２ A second recovered signal (D ２ By multiplying the function by the time (t) and integrating it with respect to time (FIG. 10), a fourth feature amount is obtained, and the amount of the detection target 410 can be calculated based on the fourth feature amount.

[0093] <<1-3>> Comparative Example Fig. 12 is a diagram showing a schematic configuration of an optical measurement system 1a (including an optical measurement device 10a) of a comparative example. In the optical measurement system 1a of the comparative example, generated light of each wavelength generated for the irradiation wavelength is measured individually. The optical measurement device 10a has a light irradiation control unit 320a that controls a light irradiation device 100 that irradiates a detection object 410 with irradiation light 110a, and a signal processing unit 310a that receives a detection signal output from a light detection device 200 that detects generated light 120a obtained from the detection object 410.

[0094] In the optical measurement system 1a of the comparative example, a photodetector 200 is provided that can modulate light of multiple wavelengths with irradiation time patterns of orthogonal codes that are different from each other, irradiate the light simultaneously, and detect the intensity of light of one or more wavelengths, and based on the irradiation time patterns of the orthogonal codes, the intensities of light generated when each of the multiple wavelengths of light modulated by the irradiation time patterns of each orthogonal code is irradiated are individually extracted from the detection signals for each wavelength detected by the photodetector 200, and the individually extracted light intensities are used as feature quantities to estimate a predetermined objective variable or its presence or absence.

[0095] FIG. 13 shows an orthogonal code C′ having a code length of “8” used in the optical measurement system 1a of the comparative example. １ (t), ..., C' ７ 1 is a diagram showing the orthogonal code C′. １ (t), ..., C' ７ (t) is created based on a Walsh code with a code length of "8".

[0096] FIG. 14 shows the wavelengths λ used in the optical measurement system 1a of the comparative example. １ , …, λ ７ 15 is a diagram showing the irradiation intensity and irradiation time pattern of the light of the comparative example. Fig. 15 is a diagram showing the irradiation intensity of the mixed light (i.e., the light obtained by combining light of a plurality of wavelengths at a predetermined irradiation intensity ratio) used in the optical measurement system 1a of the comparative example.

[0097] In the irradiated light 110a, the wavelength λ １ , …, λ Ｍ The irradiation intensity at time t is expressed as In this case, the wavelength λ ｍThe irradiation intensity of the light at time t ("irradiation intensity I ０，ｍ ") is expressed by the following equation (1.32).

[0098]

[0099] Here, C' ｍ (t) is an orthogonal code with a code length W' (=8). is a unit vector with M rows and 1 column, in which only the m-th component is 1. Furthermore, m is an integer between 1 and M. M is an integer between 1 and W'-1. That is, in the optical measurement device 10a of the comparative example, each wavelength λ ｍ The light is respectively converted into orthogonal code C' ｍ As a result, the irradiation intensity of the irradiation light 110a at time t ("irradiation intensity I ０ (t)") is expressed by the following equation (1.33).

[0100]

[0101] Of the irradiation light 110a, each wavelength λ １ , …, λ Ｍ Each detected wavelength λ' at time t generated by light １ , …, λ´ Ｎ The detection intensity at is expressed as follows:

[0102] Here, the second subscript specifies the detected wavelength, and the third subscript specifies the wavelength of the contributed light. ｍ The detection wavelength λ' generated by the light ｎ´ Detection intensity L at time t ０，ｎ´，ｍ (t) is Using this, it is expressed by the following equation (1.34).

[0103]

[0104] Detection wavelength λ′ detected by the photodetector 200 １ , …, λ´ Ｎ The detected intensity L of light at time t ０，１ (t), ..., L ０，ＮHere, the detection wavelength λ′ detected by the photodetector 200 will be described. ｎ´ The detected intensity L of light at time t ０，ｎ´ (t) is expressed as the following equation (1.35).

[0105]

[0106] Next, the signal processing unit 310a calculates the detected intensity L ０，１ (t), ..., L ０，Ｎ In (t) The restored signal D' １ (t), ..., D' Ｎ (t) is used to extract the data.

[0107] In addition, D' １ (t), ..., D' Ｎ (t) is C' １ (t), ..., C' Ｎ The restored signal is calculated based on (t). ｍ The detection wavelength λ' generated by the light ｎ´ The light intensity q ｎ´，ｍ is D' ｍ (t) is used to calculate as shown in equation (1.36).

[0108]

[0109] Next, as shown in equation (1.37), q １，１ , …, q １，Ｍ , q ２，１ , …, q ２，Ｍ , …, q Ｎ，１ , …, q Ｎ，Ｍ is used as a feature to calculate an estimated quantity ŷ' of the quantity of the detection object 410.

[0110]

[0111] Here, from equation (1.38), the estimator ŷ′ is the same value as the estimator ŷ in the first embodiment.

[0112]

[0113] That is, the output of the optical measurement device 10a of the comparative example is exactly the same as that of the optical measurement device 10. Next, as an example, an operation will be described when measuring the irradiated light 110a with the number of wavelengths M of the irradiated light being 7 and the number N of light combinations and detection wavelengths being 2. However, N is not limited to 2, and may be 1, or an integer of 3 or more.

[0114] The light irradiation device 100 emits light at wavelengths λ １ , …, λ ７ The light intensity (“Irradiation intensity I １ (t), ..., I ７ (t)"). (also referred to as "irradiation intensity I(t)") is irradiated.

[0115]

[0116] 15, the locations of the square blocks correspond to the time when light is irradiated. １ , …, λ ７ The detection wavelength λ' generated when light of １ The detected intensity of the generated light 120a ("Detection intensity q １ "), detection wavelength λ' ２ The detected intensity of the generated light 120a ("Detection intensity q ２ ") are as shown in equations (1.47) and (1.48), respectively. １ , …, λ ７ The detection wavelength λ' generated by the light １ The detected intensity L of the generated light 120a ０，１ (t), wavelength λ １ , …, λ ７ The detection wavelength λ' generated by the light ２ The detected intensity L of the generated light 120a ０，２ (t) is shown in the following equations (1.47) and (1.48).

[0117]

[0118] FIG. 16 shows the first generated light (i.e., the first detected wavelength λ′ generated in response to the mixed light of FIG. 15 ) detected by the optical measurement system 1 a of the comparative example. １ The detected intensity L ０，１ 17 is a diagram showing the second generated light (i.e., the second detected wavelength λ′ generated in response to the mixed light of FIG. 15 ) detected by the optical measurement system 1 a of the comparative example. ２ The detected intensity L ０，２ FIG.

[0119] Next, q １，１ , …, q １，７ , q ２，１ , …, q ２，７ Calculate the following. １，１ and q ２，１ The calculation formulas are shown in formulas (1.49) and (1.50).

[0120]

[0121] FIG. 18 shows the measurement process (i.e., the first detection wavelength λ′) executed by the optical measurement device 10a of the optical measurement system 1a of the comparative example. １ The detected intensity q of the detected wavelength component corresponding to the irradiation time pattern of the code length “8” is １，１ FIG. 19 is a diagram showing the measurement process (i.e., the process of calculating the second detection wavelength λ') executed by the optical measurement device 10a of the optical measurement system 1a of the comparative example. ２ The detected intensity q of the detected wavelength component corresponding to the irradiation time pattern of the code length “8” is ２，１ FIG. 10 is a diagram illustrating a process for calculating

[0122] Next, the estimated amount ŷ′ of the response variable is shown in equation (1.51).

[0123]

[0124] <<1-4>> Effects As explained above, the optical measurement device 10a of the comparative example assigns light of a single wavelength to each orthogonal code. In other words, it is necessary to prepare as many orthogonal codes as there are wavelengths of light to be irradiated. In order to increase the number of orthogonal codes, it is necessary to increase the code length W' of the orthogonal codes. For example, in the case where the number of wavelengths M-1=7 as explained in the comparative example, it is necessary to prepare seven orthogonal codes, and in this case, the code length W' is "8". In this way, in the optical measurement device 10a of the comparative example, since the code length W' is longer, it is necessary to perform correspondingly more measurements, which may result in a longer measurement time.

[0125] On the other hand, in the optical measurement device 10 according to the first embodiment, a combination of light (mixed light) obtained by mixing light of multiple wavelengths at predetermined irradiation intensities is assigned to each orthogonal code. Therefore, it is not necessary to prepare as many orthogonal codes as there are wavelengths of irradiated light; only orthogonal codes for the number of detection wavelengths are sufficient. In other words, when the number of detection wavelengths is smaller than the number of wavelengths M of irradiated light, the number of required orthogonal codes is reduced, and the code length can be reduced, thereby shortening the measurement time. Generally, the number of wavelengths M of irradiated light can be easily prepared in multiple numbers according to the number of LEDs, which are light-emitting elements, to be prepared. On the other hand, when the detection device is a monochrome camera or a color camera, the number of detection wavelengths is at most three. Therefore, in many cases, the time required for measurement according to the first embodiment can be shorter than the time required for measurement by the optical measurement device 10a of the comparative example.

[0126] <<2>> Second Embodiment <<2-1>> Configuration Fig. 20 is a diagram schematically showing the configuration of an optical measurement system 2 (including an optical measurement device 20) according to the second embodiment. In Fig. 20, elements that are the same as or correspond to elements shown in Fig. 1 are assigned the same reference numerals as those shown in Fig. 1. The optical measurement system 2 and the optical measurement device 20 according to the second embodiment differ from the optical measurement system 1 and the optical measurement device 10 according to the first embodiment in that they have a data set 600 and an irradiation intensity determination unit 500 stored in a storage device, and in the operations of a light irradiation control unit 322 and a signal processing unit 312. The data set 600 may be stored in an external storage device.

[0127] The data set 600 is made up of data collected by the optical measurement system 2 shown in FIG. 20 or a data collection optical measurement system configured similarly to the optical measurement system 2. For example, the data set 600 is acquired for each of a plurality of data collection detection targets by previously executing a data collection process, which is a process of detecting data collection generated light obtained from the data collection detection target when the data collection detection target is irradiated with data collection irradiation light. The data set 600 indicates the relationship between the wavelength and intensity of the data collection irradiation light and the wavelength and intensity of the data collection generated light. The irradiation intensity determination unit 500 uses the data of the data set 600 to determine the wavelength and intensity of the irradiation light 112 that the light irradiation device 100 irradiates the detection target 410 with (i.e., the wavelength and intensity of each of the plurality of light beams that make up the irradiation light 112).

[0128] The optical measurement device 20 can measure the amount of the detection target 410 or determine the presence or absence of the detection target 410 based on the relationship between the wavelength λ of light contained in the irradiation light 112 irradiated onto the detection target 410 and the detection wavelength λ' of light contained in the generated light 122 obtained from the detection target 410 in response to the irradiation of light of wavelength λ. The optical measurement device 20 has a light irradiation control unit 322 that controls the light irradiation device 100, a signal processing unit 312 that receives a detection signal output from the light detection device 200, a data set 600, and an irradiation intensity determination unit 500. The data set 600 may be a part of the optical measurement device 20, or may be a storage device of another device connected to the optical measurement device 20.

[0129] The optical measurement device 20 is a device capable of implementing the optical measurement method according to the second embodiment. The optical measurement device 20 is, for example, a computer. The optical measurement device 20 may be a computer system configured by cloud computing using a computer network. The hardware configuration of the optical measurement system 2 is similar to that shown in FIG. 2.

[0130] The data set 600 includes a measurement data set indicating the relationship between the wavelength and intensity of the irradiated light 112 irradiated onto the detection target 410 (i.e., the wavelength and intensity of each of the multiple light beams constituting the irradiated light 112) and the wavelength and intensity of the generated light 122, and a supervised data set indicating the amount of the detection target 410 corresponding to the data of the measurement data set (e.g., component amount, component ratio, etc.). Specifically, the data set 600 includes a measurement data set including multiple pieces of measurement data of the intensities of light of each detection wavelength generated when light of each wavelength is irradiated onto the detection target 410, and a supervised data set including multiple pieces of supervised data of the amount of the detection target 410 when each of the above measurement data was acquired. For example, the measurement data set may include a wavelength λ of unit intensity. １ , …, λ Ｍ M detection wavelengths λ′ are generated when the detection target 410 is irradiated with light of １ , …, λ´ Ｍ The intensity of the generated light (also referred to as "intensity Q of generated light") and is expressed by the following formula (2.1).

[0131] where V is the number of sets of measurement data sets.

[0132] Also, is the wavelength λ of unit intensity in the v-th measurement data, as shown in equation (2.2). １ , …, λ Ｍ is the intensity of the light generated when the light is irradiated with the light of v. v is an integer of 1 or more and V or less.

[0133]

[0134] q ｍ，ｎ，ｖ is the wavelength λ of unit intensity in the vth measurement data ｍ The detection wavelength λ' generated when light of ｎ The correct data set is the intensity of the light generated by the object 410 corresponding to each measurement data set. (also referred to as "quantity Y of the detection target"), and is expressed by the following equation (2.3).

[0135]

[0136] Here, yｖ is the amount of the detection target 410 in the v-th correct answer data. The data set 600 is configured from a database or the like.

[0137] The irradiation intensity determination unit 500 is a device that determines the weight of the light intensity of each wavelength for each combination of light to be irradiated based on the data set 600. The irradiation intensity determination unit 500 is configured by, for example, a processor that executes a program stored in a memory, as shown in FIG.

[0138] <<2-2>> Operation Next, the operation of the optical measurement system 2 and the optical measurement device 20 according to the second embodiment will be described.

[0139] The irradiation intensity determination unit 500 determines, based on the data set 600, the wavelength λ for each of the first light combination (i.e., the first mixed light) to the Nth light combination (i.e., the Nth mixed light). １ , …, λ Ｍ The weight of light (also referred to as "weight X") is calculated as shown in equation (2.4).

[0140]

[0141] where: ("weight x' ｎ ") is the weight X for each wavelength λ for the n-th light combination (i.e., mixed light). １ , …, λ Ｍ is the light weight of x'. ｎ，ｍ is the weight X for each wavelength λ for the n-th light combination ｍ It is the weight of light.

[0142] First, the intensity Q of the generated light is calculated using the training measurement data set as shown in equations (2.5) and (2.6). ("Training measurement dataset Q ０ ") and a test measurement dataset ("Test measurement data set Q １ ") and

[0143] Furthermore, the quantity Y of the detection target is expressed as the training correct answer data set as shown in equations (2.7) and (2.8). ("Training data set Y ０ ") and a test measurement dataset ("Test measurement data set Y １ ") and V ０ is an integer equal to or greater than 1 and less than V.

[0144]

[0145] Next, each weight is calculated by partial least squares regression with the constraint that the weights are non-negative. ("weight x' １ , …, x' Ｎ The specific calculation method is described below.

[0146] Training correct answer dataset Y ０ The weights shown in equation (2.9) are used to maximize the variance of ("Weight P １ ") is used to obtain the training measurement data set Q ０ The first principal component of The process of calculating the following will be described.

[0147]

[0148] Here, in partial least squares regression, as will be described later, the weights ("weight x ｎ ") is the weight P １ The weight x ｎ corresponds to the irradiation intensity, each component is assumed to be non-negative. １ The condition is that each component of is also non-negative.

[0149] is calculated by maximizing the objective function G using Lagrange's undetermined multiplier method shown in equation (2.11).

[0150]

[0151] Here, the Karush-Kuhn-Tucker condition is The normalization condition and, Each component of is 0 or more, that is, p ｎ，ｍ，１ ≧0. Also, η, ξ ｎ，ｍ is the Karush-Kuhn-Tucker multiplier.

[0152] The solution to this optimization problem is is found as a solution that satisfies equations (2.12) to (2.16).

[0153]

[0154] where: Transforming equation (2.12) gives equation (2.17).

[0155]

[0156] Here, twist Since the norm of is 1, We used the fact that

[0157] next, Each component of The cases are divided according to the size of p ｎ，ｍ，１ Explain that the value is >0.

[0158] When , ξ ｎ，ｍ ≧0, so p ｎ，ｍ，１ > 0. Therefore, ξ ｎ，ｍ p ｎ，ｍ，１ In order to satisfy the condition of ξ = 0, ｎ，ｍ = 0. In other words, the following equation holds true:

[0159]

[0160] When This becomes:

[0161] Also, ξ ｎ，ｍ p ｎ，ｍ，１ Considering the condition of =1, p ｎ，ｍ，１ =ξ ｎ，ｍ = 0. That is, p ｎ，ｍ，１=0.

[0162] When p ｎ，ｍ，１ Considering the necessity for ξ ｎ，ｍ >0. Also, ξ ｎ，ｍ p ｎ，ｍ，１ Considering the condition of =0, p ｎ，ｍ，１ =0.

[0163] To sum up, can be expressed as the following equation (2.18).

[0164]

[0165] Here, ReLU(θ) is a function that outputs θ when the real number θ is non-negative and outputs 0 when θ is negative. In other words, partial least squares regression with the constraint that each weight must be non-negative is partial least squares regression that replaces negative components in each principal component with 0.

[0166] Using Calculate.

[0167] next, Using the squared error Minimize loading , u １ Calculate.

[0168] and １ is calculated by the least squares method as shown in equations (2.19) and (2.20).

[0169]

[0170] next, Residuals of The weight vector with the maximum variance The second principal component shown in equation (2.21) Calculate.

[0171]

[0172] however, is an identity matrix with MN rows and MN columns.

[0173] Next, Using the objective function Minimize , u ２ Calculate.

[0174] is calculated by the same argument using equations (2.22) to (2.24).

[0175]

[0176] The above process is V ０ By repeating this process, the weight vector and the main component And loading can be obtained.

[0177] The above process was repeated r times to obtain are shown in the following equations (2.25) to (2.28).

[0178]

[0179] The above calculated Using to the target variable This explains how to estimate

[0180] First, the r-th principal component shown in equation (2.29) From the first principal component to the V ０ To the main ingredient Calculate.

[0181]

[0182] Next, the first principal component to the rth principal component shown in equation (2.30) were used. Estimator of The estimator of the objective variable using the first principal component is calculated using the formula From the first principal component to the Lth principal component ０ Estimator of the dependent variable using up to the principal components Calculate.

[0183]

[0184] where: As shown in equation (2.31), each wavelength λ for the first light combination to the Nth light combination using the first principal component to the rth principal component is １ , …, λ Ｍ It is the weight of light.

[0185]

[0186] In other words, is calculated by the following formula (2.32).

[0187]

[0188] Next, as shown in equation (2.33), The error function E ｒ The formula for calculating The error function E １ , ..., E Ｌ０ Calculate.

[0189]

[0190] The number of principal components R used to estimate is determined by the error function E as shown in equation (2.34). ｒ is the minimum number of components.

[0191]

[0192] The error function E ｒ may be calculated by other formulas. The number of components R may be determined by preparing the following:

[0193] Using the number of components R selected above is shown in the following equation (2.35).

[0194]

[0195] From the above, from the first light combination to the Nth light combination, each wavelength λ １ , …, λ Ｍ The weight of light Determine.

[0196] In addition, may be calculated by other methods instead of by partial least squares regression with the constraint that each weight is non-negative. For example, it may be calculated by principal component regression with the constraint that each weight is non-negative. Principal component regression with the constraint that each weight is non-negative is a principal component regression in which negative components in each principal component are replaced with 0.

[0197] The light irradiation device 100 is determined Based on this, the irradiation light 112 is irradiated in the same manner as in the first embodiment.

[0198] The photodetector 200 detects the generated light 122 generated by the combination of the lights at each detection wavelength in the same manner as in the first embodiment.

[0199] As in the first embodiment, the signal processing unit 312 calculates a feature quantity for the amount of the detection target 410. The amount of the detection target 410 is estimated using the above equation. The presence or absence of the detection target 410 may be estimated based on the estimated amount of the detection target 410. Alternatively, the amount of the adhesion of the detection target 410 may be determined as one of classes such as class 1, class 2, class 3, etc.

[0200] <<2-3>> Effects As described above, by using the optical measurement system 2 and the optical measurement device 20 according to the second embodiment, the weight determined by the irradiation intensity determination unit 500 can be is the dataset As shown in equation (2.34), the weights are set to minimize the estimation error of the amount of the detection target 410, that is, maximize the estimation accuracy. In other words, the optical measurement system 2 and the optical measurement device 20 according to the second embodiment can estimate the amount of the detection target 410, the presence or absence of the detection target 410, or the class of the detection target 410 with high accuracy.

[0201] <<3>> Embodiment 3 <<3-1>> Configuration Fig. 21 is a diagram schematically showing the configuration of an optical measurement system 3 (including an optical measurement device 30) according to embodiment 3. In Fig. 21, elements that are the same as or correspond to elements shown in Fig. 1 are assigned the same reference numerals as those shown in Fig. 1. The optical measurement system 3 and the optical measurement device 30 according to embodiment 3 differ from the optical measurement system 1 and the optical measurement device 10 according to embodiment 1 in that they have a data set 600 and an irradiation intensity determination unit 510 stored in a storage device, and in the operations of a light irradiation control unit 323 and a signal processing unit 313. The data set 600 may be stored in an external storage device.

[0202] As in the second embodiment, the data set 600 is made up of data collected by the optical measurement system 3 or a data collection optical measurement system configured similarly to the optical measurement system 3. For example, the data set 600 is acquired for each of a plurality of data collection detection targets by previously executing a data collection process, which is a process of detecting data collection generated light obtained from the data collection detection target when the data collection detection target is irradiated with data collection irradiation light. The data set 600 indicates the relationship between the wavelength and intensity of the data collection irradiation light and the wavelength and intensity of the data collection generated light. The irradiation intensity determination unit 500 uses the data of the data set 600 to determine the wavelength and intensity of the irradiation light 113 that the light irradiation device 100 irradiates the detection target 410 with (i.e., the wavelength and intensity of each of the plurality of light beams that make up the irradiation light 113).

[0203] The optical measurement device 20 can measure the amount of the detection target 410 or determine the presence or absence of the detection target 410 based on the relationship between the wavelength λ of light contained in the irradiation light 112 irradiated onto the detection target 410 and the detection wavelength λ' of light contained in the generated light 122 obtained from the detection target 410 in response to the irradiation of light of wavelength λ. The optical measurement device 20 has a light irradiation control unit 322 that controls the light irradiation device 100, a signal processing unit 312 that receives a detection signal output from the light detection device 200, a data set 600, and an irradiation intensity determination unit 500. The data set 600 may be a part of the optical measurement device 20, or may be a storage device of another device connected to the optical measurement device 20.

[0204] The optical measurement device 30 is a device capable of implementing the optical measurement method according to the third embodiment. The optical measurement device 30 is, for example, a computer. The optical measurement device 30 may be a computer system configured by cloud computing using a computer network. The hardware configuration of the optical measurement system 3 is similar to that shown in FIG. 2.

[0205] The irradiation intensity determination unit 510 is a device that determines the weight of light of each wavelength for each combination of light to be irradiated based on the data set 600.

[0206] The signal processing unit 313 is a device that performs signal processing on the intensity of light of one or more predetermined wavelengths detected by the photodetector 200 and estimates the amount or presence or absence of the detection target 410 .

[0207] <3-2> Operation An overview of the operation of the third embodiment will be described. In the third embodiment, the weights of the intensity of the irradiated light 113 are calculated using partial least squares regression. However, if the constraint that each component of each weight must be nonnegative is not imposed, there is a possibility that one of the components will be nonnegative. This means irradiating a negative intensity, which is physically impossible. Therefore, each weight is divided into weights whose components are composed of nonnegative values ​​and weights whose components are composed of only negative values. For weights whose components are composed of only negative values, a nonnegative intensity with the sign reversed is irradiated. Next, the intensity of light detected using weights that can be either positive or negative is reproduced by calculating the difference between the detected intensity of light generated by combining light using weights composed of nonnegative values ​​and the detected intensity of light generated by combining light using weights composed of negative values.

[0208] The operation of the irradiation intensity determination unit 510 will be described. The irradiation intensity determination unit 510 operates in substantially the same manner as the irradiation intensity determination unit 500 of the second embodiment. First, as shown in formula (3.1), the irradiation intensity determination unit 510 determines the wavelengths λ for the first light combination (i.e., the first mixed light) to the Nth light combination (i.e., the Nth mixed light). １ , …, λ Ｍ Weight of Calculate.

[0209]

[0210] where: is the wavelength λ for the nth light combination １ , …, λ Ｍ is the weight of light. ｎ，ｍ is the wavelength λ for the nth light combination ｍ It is the weight of light.

[0211] In the third embodiment, unlike the second embodiment, instead of the objective function G, G shown in the following equation (3.2) is used: １ Use.

[0212]

[0213] In the third embodiment, unlike the second embodiment, The constraint that each component must be 0 or greater is lifted.

[0214] This means that is calculated by the following formula (3.3).

[0215]

[0216] Other processes in the third embodiment are performed in the same manner as in the second embodiment. Calculate.

[0217] Next, as shown in equation (3.4), the weight In this case, the weights extracted are non-negative components. and, as shown in equation (3.5), the weight In this case, the negative components are extracted and multiplied by -1. Divide into.

[0218]

[0219] where: teeth, Each wavelength λ for the nth light combination in １ , …, λ Ｍ Each component of light is a weight consisting of a non-negative value.

[0220] Also, x"ｎ，ｍ，＋ teeth, Each wavelength λ for the nth light combination in ｍ It is the weight of light.

[0221] Also, teeth, Each wavelength λ for the nth light combination in １ , …, λ Ｍ Each component of is a weight consisting of a non-negative value.

[0222] Also, x" ｎ，ｍ，－ teeth, Each wavelength λ for the nth light combination in ｍ It is the weight of light.

[0223] In addition, The relational expression (3.6) holds true.

[0224]

[0225] In addition, The weights may be determined by other methods than partial least squares regression, for example, by principal component regression.

[0226] The light irradiation device 100 emits light having M wavelengths λ １ , …, λ Ｍ Each light is assigned a predetermined weight A different orthogonal code C" is generated for each of the N combinations of light obtained by adding １ (t), ..., C" Ｎ (t) and M wavelengths λ １ , …, λ Ｍ Each light is assigned a predetermined weight For each of the N combinations of light obtained by adding Ｎ＋１ (t), ..., C" ２Ｎ The light modulated by (t) and the irradiation light 112 are irradiated. １ (t), ..., C" Ｎ (t), C″ Ｎ＋１ (t), ..., C" ２Ｎ (t) is an orthogonal code of length 2W.

[0227] The photodetector 200 detects light generated by a combination of light beams at each detection wavelength, similarly to the first embodiment. The detected intensity of the irradiated light 113 generated by a combination of light beams at each wavelength at time t is denoted by L″. １，１ (t), ..., L" １，Ｎ (t), ..., L" Ｎ，１ (t), ..., L" Ｎ，Ｎ Here, the first subscript specifies the detected wavelength, and the second subscript specifies the type of light combination that contributed. In this case, the wavelength λ generated by the nth light combination is ｎ´ The detected intensity L″ of the generated light 123 at time t ｎ´，ｎ (t) is expressed as equation (3.7).

[0228]

[0229] The wavelength λ detected by the photodetector 200 １ , …, λ Ｍ The detected intensity L″ of the generated light 123 at time t １ (t), ..., L" Ｎ Here, the wavelength λ detected by the photodetector 200 is ｎ´ The detected intensity L of the generated light 123 at time t ｎ´ (t) is expressed as equation (3.8).

[0230]

[0231] The signal processing unit 313 generates the orthogonal code C'' １ (t), ..., C" Ｎ (t) and the orthogonal code C″ Ｎ＋１ (t), ..., C" ２Ｎ (t), the detected intensity L″ for each wavelength detected by the photodetector 200 ｎ´ From (t), the intensity of light generated when the combination of the light modulated by the irradiation time pattern of each orthogonal code is irradiated is are extracted individually.

[0232] next, From By taking the difference of Calculate.

[0233] calculated is used as the feature quantity. In other words, the feature quantity is the difference between the light intensities of the detected signals of light of the same wavelength among the extracted light intensities. Next, an estimated quantity y^ of the quantity of the detection target 410 is calculated as shown in equation (3.9).

[0234]

[0235] <<3-3>> Effects As described above, when the optical measurement system 3 and the optical measurement device 30 according to the third embodiment are used, the feature amount is the intensity of the light extracted by the signal processing unit 313. The difference between the light intensities of the detection signals of light of the same wavelength was taken. It states that:

[0236] That is, the intensity of light generated by the irradiated light is detected using pseudo-weights that include both positive and negative values, and the feature amount is calculated. Therefore, there is no need to impose the constraint that "each weight is non-negative" on the weights calculated by partial least squares regression, principal component regression, or the like, as in the second embodiment. That is, in the third embodiment, the weights calculated by partial least squares regression, principal component regression, or the like can be faithfully reproduced, and therefore the amount of the detection target 410, the presence or absence of the detection target 410, or the class of the detection target 410 can be estimated with high accuracy.

[0237] 1, 2, 3 Optical measurement system, 10, 20, 30 Optical measurement device, 100 Light irradiation device, 110, 112, 113 Irradiated light, 120, 122, 123 Generated light, 200 Light detection device, 310, 312, 313 Signal processing unit, 320, 322, 323 Light irradiation control unit, 400 Member, 410 Detection object, 500, 510 Irradiation intensity determination unit, 600 Data set.

Claims

1. An optical measurement device comprising: a light irradiation control unit that controls a light irradiation device that irradiates a detection object with irradiation light; and a signal processing unit that receives a detection signal output from a light detection device that detects generated light obtained from the detection object irradiated with the irradiation light, wherein the light irradiation control unit: prepares a first orthogonal code having a code length W, where W is an integer equal to or greater than 2; prepares a first mixed light composed of M wavelengths of light mixed at a first irradiation intensity ratio, where M is an integer equal to or greater than 2; causes the light irradiation device to irradiate the detection object with the irradiation light including the first mixed light having a first irradiation intensity and a first irradiation time pattern corresponding to the first orthogonal code; and the signal processing unit: receives a first detection intensity of light of a first detection wavelength generated by irradiation with the irradiation light as the detection signal; and performs a first process of calculating a first intensity of light of the first detection wavelength generated by irradiation with the first mixed light based on the first detection intensity and the first orthogonal code.

2. The optical measurement device according to claim 1, characterized in that the light irradiation control unit further prepares a second orthogonal code having the code length W, further prepares a second mixed light composed by mixing the light of the M wavelengths at a second irradiation intensity ratio, causes the light irradiation device to irradiate the detection object with the irradiation light including the second mixed light having a second irradiation time pattern corresponding to the second irradiation intensity and the second orthogonal code, and the signal processing unit performs a second process to calculate a second intensity of the light of the first detection wavelength generated by irradiation of the second mixed light based on the first detection intensity and the second orthogonal code.

3. The optical measurement device according to claim 2, characterized in that the signal processing unit receives, as the detection signal, a second detection intensity of light of a second detection wavelength different from the first detection wavelength generated by irradiation of the irradiation light, and performs a third process of calculating a third intensity of light of the second detection wavelength generated by irradiation of the first mixed light based on the second detection intensity and the first orthogonal code.

4. The optical measurement device according to claim 3, characterized in that the signal processing unit performs a fourth process of calculating a fourth intensity of the light of the second detection wavelength generated by irradiation of the second mixed light based on the second detection intensity and the second orthogonal code.

5. The optical measurement device described in claim 2, characterized in that when performing the first processing, the signal processing unit obtains a first characteristic amount by performing time integration of a function obtained by multiplying the first detection intensity by a first restored signal, which is a Walsh code corresponding to the first orthogonal code, and calculates the amount of the detection object based on the first characteristic amount; and when performing the second processing, obtains a second characteristic amount by performing time integration of a function obtained by multiplying the first detection intensity by a second restored signal, which is a Walsh code corresponding to the second orthogonal code, and calculates the amount of the detection object based on the second characteristic amount.

6. The optical measurement device described in claim 4, characterized in that when performing the third processing, the signal processing unit obtains a third feature by performing time integration of a function obtained by multiplying the second detection intensity by a first restored signal, which is a Walsh code corresponding to the first orthogonal code, and calculates the amount of the detection object based on the third feature, and when performing the fourth processing, obtains a fourth feature by performing time integration of a function obtained by multiplying the second detection intensity by a second restored signal, which is a Walsh code corresponding to the second orthogonal code, and calculates the amount of the detection object based on the fourth feature.

7. The optical measurement device of claim 2, wherein each of the first orthogonal code and the second orthogonal code is composed of an array of combinations of 1's and 0's, the array contains an equal number of 1's and 0's, the value of the inner product of the first orthogonal codes is equal to the value of the inner product of the second orthogonal codes, and the value of the inner product of the first orthogonal codes and the second orthogonal codes is half the value of the inner product of the first orthogonal codes.

8. An optical measurement device according to any one of claims 1 to 7, further comprising an irradiation intensity determination unit that determines the wavelength and intensity of light to be irradiated to the detection target by the light irradiation device using a data set indicating the relationship between the wavelength and intensity of the data collection irradiation light and the wavelength and intensity of the data collection generated light, which is acquired for each data collection detection target by previously executing data collection to detect data collection generated light obtained from the data collection detection target when the data collection irradiation light is irradiated to the data collection detection target.

9. The optical measurement device described in claim 8, characterized in that the data set includes: a measurement data set indicating the relationship between the wavelength and intensity of the light irradiated to the detection object and the wavelength and intensity of the generated light; and a correct answer data set indicating the quantity of the detection object corresponding to the data of the measurement data set.

10. An optical measurement system comprising: a light irradiation device which irradiates an object to be detected with irradiation light; a light detection device which detects light generated from the object to be detected irradiated with the irradiation light; a light irradiation control unit which controls the light irradiation device; and a signal processing unit which receives a detection signal output from the light detection device, wherein the light irradiation control unit: prepares a first orthogonal code having a code length W, where W is an integer equal to or greater than 2; prepares a first mixed light by mixing light of M wavelengths at a first irradiation intensity ratio, where M is an integer equal to or greater than 2; causes the light irradiation device to irradiate the object to be detected with the irradiation light including the first mixed light having a first irradiation intensity and a first irradiation time pattern corresponding to the first orthogonal code; and the signal processing unit: receives a first detection intensity of light of a first detection wavelength generated by irradiation with the irradiation light as the detection signal; and performs a first process of calculating a first intensity of light of the first detection wavelength generated by irradiation with the first mixed light based on the first detection intensity and the first orthogonal code.

11. An optical measurement method executed by an optical measurement device that controls a light irradiation device that irradiates an object to be detected with irradiation light and receives a detection signal output from a light detection device that detects light generated from the object to be detected irradiated with the irradiation light, the optical measurement method comprising the steps of: preparing a first orthogonal code having a code length W, where W is an integer equal to or greater than 2; preparing a first mixed light composed of a mixture of light of M wavelengths at a first irradiation intensity ratio, where M is an integer equal to or greater than 2; irradiating the object to be detected with the irradiation light from the light irradiation device, the first mixed light having a first irradiation intensity and a first irradiation time pattern corresponding to the first orthogonal code; receiving a first detection intensity of light of a first detection wavelength generated by irradiation with the irradiation light as the detection signal; and performing a first process of calculating a first intensity of light of the first detection wavelength generated by irradiation with the first mixed light based on the first detection intensity and the first orthogonal code.

12. An optical measurement program executed by a computer that controls a light irradiation device that irradiates an object to be detected with irradiation light and receives a detection signal output from a light detection device that detects generated light obtained from the object to be detected irradiated with the irradiation light, wherein the optical measurement method is executed by an optical measurement device that controls a light irradiation device that irradiates an object to be detected with irradiation light and receives a detection signal output from the light detection device that detects generated light obtained from the object to be detected with the irradiation light, the optical measurement method comprising the steps of: preparing a first orthogonal code having a code length W, where W is an integer equal to or greater than 2; preparing a first mixed light composed of M wavelengths of light mixed at a first irradiation intensity ratio, where M is an integer equal to or greater than 2, irradiating the object to be detected with the irradiation light including the first mixed light having a first irradiation intensity and a first irradiation time pattern corresponding to the first orthogonal code, receiving a first detection intensity of light of a first detection wavelength generated by irradiation with the irradiation light as the detection signal, a first processing for calculating a first intensity of light of the first detection wavelength generated by irradiation of the first mixed light based on the first detection intensity and the first orthogonal code.

13. An optical measurement device comprising: a light irradiation control unit that prepares one or more mixed lights, which are combinations of light obtained by mixing light of multiple wavelengths at a predetermined irradiation intensity, and controls a light irradiation device to modulate the combinations of light with irradiation time patterns of different orthogonal codes and irradiate them simultaneously; and a signal processing unit that receives detection signals output from a light detection device that detects light generated from a detection object irradiated with the irradiation light, wherein the signal processing unit individually extracts the intensity of light generated when the combinations of light modulated by the irradiation time patterns of each orthogonal code are irradiated from the detection signals of light for each wavelength detected by the light detection device based on the irradiation time patterns of the orthogonal codes, and estimates the amount or presence or absence of the detection object using the intensity of light as a feature.

14. The optical measurement device described in claim 13, further comprising a dataset consisting of a measurement dataset regarding the intensity of light of each wavelength detected by the signal processing unit when each of the plurality of wavelengths of light previously acquired is irradiated onto the detection object, and a corresponding ground truth dataset of the amount of the detection object, wherein the signal processing unit determines the predetermined irradiation intensity of each of the plurality of wavelengths of light irradiated by the light irradiation device based on the dataset.

15. The number of combinations of the light is N (N is a positive integer), the number of wavelengths of the generated light detected by the light detection device is N, and each wavelength of the generated light is defined as a detection wavelength λ' １ , …, λ′ Ｎ The number of wavelengths of the combination of light irradiated by the light irradiation device is M (M is an integer of 2 or more), and each wavelength of the combination of light is λ １ , …, λ Ｍ where N is an integer less than M, and the measurement data set is divided into first to Vth measurement data by wavelengths λ 1 , λ 2 , and λ 3 . １ , …, λ Ｍ Each of the N detection wavelengths λ' generated when light of １ , …, λ′ Ｎ , the intensity per unit intensity q １，１，１ , …, q Ｎ，Ｍ，Ｖ The correct answer data set is expressed as a matrix Q having M N rows and V columns, and the amount y of the detection object corresponding to each measurement data set is expressed as follows, as shown in equation (2a): １ , ..., y Ｖ Q is the training measurement data set Q as shown in equations (3a) and (4a). ０ and the test measurement dataset Q １ The data set Y is divided into a training correct answer data set Y ０ and the test measurement data set Y １ Each wavelength λ for each of the first to Nth combinations of light is １ , …, λ Ｍ The irradiation intensity of P shown in formulas (7a), (8a), (9a), and (10a) is ｒ , z ０ｒ , s ｒ , u ｒ Using the weights shown in Equation (11a), ReLU(θ) is a function that outputs θ when the real number θ is non-negative and outputs 0 when θ is negative; ＭＮ is a unit matrix with M rows and M columns, R is a predetermined integer between 1 and V0, and the formulas (1a) to (11a) are as follows:

15. The optical measurement device according to claim 14.

16. The optical measurement device according to claim 15, characterized in that the feature amount is a difference between the light intensities of detection signals of light of the same wavelength in the light intensities extracted by the signal processing unit.

17. The number of combinations of the light is 2N, the number of wavelengths detected by the light detection device is N, and each wavelength is λ' １ , …, λ′ Ｎ The number of wavelengths irradiated by the light irradiation device is M, and each wavelength is λ １ , …, λ Ｍ where 2N is a positive integer less than M, and the measurement data set is represented by the excitation wavelengths λ in the 1st, ..., Vth measurement data as shown in formula (1b). １ , …, λ Ｍ Each of the N detection wavelengths λ' generated when light of １ , …, λ′ Ｎ Fluorescence intensity per unit intensity q １，１，１ , …, q Ｎ，Ｍ，Ｖ The correct data set is expressed as a matrix Q having M N rows and V columns, which is a compilation of the above. The correct data set is expressed as a response variable y １ , ..., y Ｖ The matrix Q is expressed as the training measurement data set Q as shown in equations (3b) and (4b). ０ and the test measurement dataset Q １ As shown in equations (5b) and (6b), the data set Y is divided into a training correct data set Y ０ and the test measurement data set Y １ and P shown in formulas (7b) to (10b) ｒ , z ０ｒ , s ｒ , u ｒ Using the weights shown in equation (11b), is determined, ReLU(θ) is a function that outputs θ when the real number θ is non-negative and outputs 0 when θ is negative, and I ＭＮ is an identity matrix with M rows and M columns, and R is v or more than V ０ each wavelength λ for each of the 1st, ..., Nth combinations of light is a predetermined integer below １ , …, λ Ｍ The irradiation intensity is Using the weights shown in equation (12b), Each wavelength λ for each of the N+1th, ..., 2Nth combinations of light is determined to be proportional to １ , …, λ Ｍ The irradiation intensity is expressed by the weights shown in formula (13b). In the light intensity individually extracted by the signal restoration unit, The light intensity generated when each of these is irradiated is calculated as a weight. The feature value is calculated by subtracting the intensity of light generated when the light is irradiated with the weight. The formulas (1b) to (13b) are as follows:

17. The optical measurement device according to claim 16.

18. An optical measurement device as claimed in any one of claims 13 to 17, characterized in that the orthogonal code is composed of a combination of 1s and 0s, the number of 1s and 0s is half the length of the sequence of the irradiation time pattern of the orthogonal code, and the inner product of two identical orthogonal codes and a sequence composed of all 1s is twice as large as the inner product of a different orthogonal code.

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