WO2013099509A1

WO2013099509A1 - Signal processing device and signal processing method

Info

Publication number: WO2013099509A1
Application number: PCT/JP2012/080871
Authority: WO
Inventors: 西村　拓也
Original assignee: ソニー株式会社
Priority date: 2011-12-29
Filing date: 2012-11-29
Publication date: 2013-07-04
Also published as: JP2013150772A; TW201338754A

Abstract

Provided is an optical circulation measurement device with which a simple configuration and process are implemented. A signal processing device comprises: a light emitting unit which outputs an optical signal including light of a plurality of different wavelengths; a light receiving unit which receives either transmitted or reflected light of the optical signal of the light emitting unit via a human body, and selectively receives the light of a plurality of different wavelengths; and a signal processing unit which executes a signal process on an electrical signal which corresponds to a received light signal of the light receiving unit. The light emitting unit further comprises a white LED as a light emitting element. The light receiving unit further comprises a blue photodiode and a red photodiode. The signal processing unit receives input of the electrical signal based on the received light signal corresponding to the light of the plurality of different wavelengths, removes noise caused by bodily movement, and generates a detection signal of blood oxygen concentration, etc.

Description

Signal processing apparatus and signal processing method

The present disclosure relates to a signal processing device and a signal processing method. In particular, the present invention relates to a signal processing apparatus and a signal processing method for performing an optical blood flow analysis process.

An optical blood flow detection device is used as a device for measuring biological information (vital sign) such as a pulse rate, blood oxygen saturation, and a respiratory pattern for the purpose of health management and diagnosis. In addition, about an optical blood-flow detection apparatus, patent document 1 (patent 4581480 gazette) has description, for example.

This optical blood flow detection device has a configuration that irradiates light to the human body such as a finger from the outside. Specifically, light of multiple wavelengths (generally red and infrared) is projected onto the human body, the transmitted light or reflected light is measured, and the difference in the absorption coefficient of blood depending on the wavelength is used to obtain a signal due to body movement. It absorbs fluctuations in blood and measures blood oxygen saturation (pulse oximeter).

The conventional technology realizes measurement of transmitted or reflected light for each wavelength by alternately illuminating multiple light sources and distributing the received signal obtained from the photoreceiver such as a photodiode to the amplifier circuit according to the emission timing. I have done it. This requires a plurality of light sources, and a circuit that illuminates them alternately and distributes the received light signals in accordance with the timing is complicated, and the structure is complicated.

Japanese Patent No. 4581480

The present disclosure aims to provide a signal processing device and a signal processing method for realizing an optical blood flow detection device with a simple configuration.

The first aspect of the present disclosure is:
A light-emitting unit composed of a single light-emitting element that outputs an optical signal including light of a plurality of different wavelengths;
A light receiving unit that receives transmitted light or reflected light through a human body of a light emission signal of the light emitting unit, each of which includes a plurality of light receiving elements that output light reception signals corresponding to different wavelength light; and
The signal processing apparatus includes a signal processing unit that performs signal processing based on light reception signals of a plurality of different wavelength lights output from the light receiving unit.

Furthermore, in an embodiment of the signal processing device according to the present disclosure, the light emitting unit includes a white LED as the single light emitting element.

Furthermore, in an embodiment of the signal processing device of the present disclosure, the white LED is a light emitting element that outputs light of a plurality of different wavelengths including red light and blue light.

Furthermore, in one embodiment of the signal processing device of the present disclosure, the white LED is a light emitting element that outputs light of a plurality of different wavelengths including red light to blue light, and includes a wavelength region of red light and blue light. It is a light emitting element that outputs light having a relative intensity having a peak in a wavelength region.

Furthermore, in an embodiment of the signal processing device of the present disclosure, the light receiving unit is configured by a multi-color light emitting LED having a plurality of photodiodes that selectively receive light of different wavelengths.

Furthermore, in an embodiment of the signal processing device of the present disclosure, the light receiving unit includes a blue photodiode and a red photodiode as the plurality of light receiving elements.

Furthermore, in one embodiment of the signal processing device of the present disclosure, the blue photodiode outputs a signal corresponding to the intensity of the blue wavelength component included in the light reception signal, and the red photodiode is a red light included in the light reception signal. A signal corresponding to the intensity of the wavelength component is output.

Furthermore, in one embodiment of the signal processing device according to the present disclosure, the signal processing unit inputs an electric signal based on a received light signal corresponding to a plurality of different wavelength lights, and removes noise caused by body movement, thereby removing noise. Perform signal analysis based on the signal.

Furthermore, in an embodiment of the signal processing device of the present disclosure, the signal processing unit includes a pulse detection unit that performs pulse detection according to the output of the light receiving unit.

Furthermore, in an embodiment of the signal processing device of the present disclosure, the signal processing unit includes an oxygen concentration detection unit that detects a blood oxygen concentration according to an output of the light receiving unit.

Furthermore, in an embodiment of the signal processing device of the present disclosure, the oxygen concentration detection unit performs blood oxygen concentration detection based on comparison of signal intensities of detection signals of different wavelength lights.

Furthermore, the second aspect of the present disclosure is:
A signal processing method executed in a signal processing device,
A light emitting step in which the light emitting unit outputs an optical signal including light of a plurality of different wavelengths from a single light emitting element;
The light receiving unit is a light receiving step for receiving transmitted light or reflected light through the human body of the light emission signal of the light emitting unit, and each of the plurality of light receiving elements that output light reception signals corresponding to different wavelength light has different wavelength light A light receiving step for generating a light receiving signal of
In the signal processing method, the signal processing unit executes a signal processing step of executing signal processing based on light receiving signals of a plurality of different wavelength lights output from the light receiving unit.

Further objects, features, and advantages of the present disclosure will become apparent from a more detailed description based on embodiments of the present disclosure described below and the accompanying drawings. In this specification, the system is a logical set configuration of a plurality of devices, and is not limited to one in which the devices of each configuration are in the same casing.

According to the configuration of an embodiment of the present disclosure, an optical blood flow measurement device that realizes a simple configuration and processing is realized.
Specifically, a light emitting unit that outputs an optical signal including light of a plurality of different wavelengths, and a light receiving unit that receives transmitted light or reflected light through the human body of the light emission signal of the light emitting unit, and light having a plurality of different wavelengths A light receiving unit that selectively receives light and a signal processing unit that performs signal processing on an electrical signal corresponding to a light reception signal of the light receiving unit. The light emitting unit includes a white LED as a light emitting element, the light receiving unit includes a blue photodiode and a red photodiode, and the signal processing unit outputs an electric signal based on a light receiving signal corresponding to a plurality of different wavelength lights. Inputs noise removal caused by body movement, blood oxygen concentration detection signal, etc.

It is a figure explaining the principle of an optical blood-flow detection apparatus. It is a figure explaining the basic structural example of an optical blood-flow detection apparatus. It is a figure explaining the structural example of the conventional light emission part. It is a figure explaining the example of the emission spectrum distribution of monochromatic LED used for the conventional light emission part. It is a figure explaining the structural example of the conventional light-receiving part. It is a figure explaining the structural example of the signal processing apparatus of this indication. It is a figure explaining the structural example of the light emission part of the signal processing apparatus of this indication. It is a figure which shows the example of the emission spectrum distribution of white LED201 of the light emission part 101 shown in FIG. It is a figure explaining the structural example of the light-receiving part of the signal processing apparatus of this indication. It is a figure explaining the structural example of the signal processing part of the signal processing apparatus of this indication. It is a figure which shows the difference in the light absorption characteristic of the oxygenated hemoglobin in blood, and a reduced hemoglobin.

Hereinafter, the signal processing device and the signal processing method of the present disclosure will be described in detail with reference to the drawings. The description will be made according to the following items.
1. 1. Principle of optical blood flow detection device and basic configuration example 2. Configuration and processing of optical blood flow detection device of present disclosure 2-1. Configuration and processing of light emitting unit of signal processing apparatus for executing optical blood flow analysis of present disclosure 2-2. Configuration and processing of light receiving unit of signal processing device for executing optical blood flow analysis of present disclosure 2-3. Configuration and processing of signal processing unit of signal processing device for executing optical blood flow analysis of present disclosure 2-4. 2. Configuration and processing characteristics and advantages of the signal processing apparatus of the present disclosure Summary of composition of this disclosure

[1. Principle of optical blood flow detection device and basic configuration example]
First, the principle and basic configuration example of an optical blood flow detection device will be described.
FIG. 1 illustrates the principle of the optical blood flow detection device. A basic configuration example of the optical blood flow detection device is shown in FIG.
As shown to Fig.1 (a), light is projected with respect to the site | part which has arterial blood of the human body 10, for example, skin, and the permeation | transmission or reflected light is measured.
The light projecting part is directed from the skin surface to the inside.
Arterial blood layer 11,
Venous blood layer 12,
Tissue 13 other than blood,
Such a portion having a plurality of different layers is preferable.

Light is irradiated from the skin surface to the component part of the human body 10 having such a multilayer structure, and the time variation of the transmitted light or reflected light is measured.
This measurement result is, for example, data shown in FIG. In FIG. 1B, the horizontal axis indicates time (t), and the vertical axis indicates the intensity of transmitted light.
The transmitted light intensity changes according to the fluctuation of the blood volume at the light irradiation site due to blood circulation.
The wave of the graph shown in the figure is synchronized with the heartbeat. The intensity of transmitted light or reflected light changes according to the amount of oxygen in blood, so-called blood oxygen concentration.
Thus, by irradiating light from the skin surface and measuring the time variation of the transmitted light or reflected light, it is possible to obtain a biological signal such as a pulse or blood oxygen concentration.

FIG. 2 is a diagram illustrating a basic configuration example of the optical blood flow detection device.
The optical blood flow detection device 20 illustrated in FIG. 2 includes a light emitting unit 21, a light receiving unit 22, an amplification unit 23, and a signal processing unit 24.
Light is emitted from the light emitting unit 21 to the living tissue 30 having a human blood vessel.
The light transmitted through the living tissue 30 including blood vessels is input to the light receiving unit 22.
An electric signal based on the detection light of the light receiving unit 22 is input to the amplification unit 23 and amplified.
The electric signal of the amplifying unit 23 is input to the signal processing unit 24, and for example, signal processing such as noise removal and waveform shaping is executed, and a biological signal 50 as a measurement result is output.

As an apparatus using this optical blood flow detection processing method, for example, there is a pulse oximeter. The pulse oximeter measures chemical components contained in blood, such as oxygen concentration, by utilizing arterial blood fluctuations and differences in light absorption characteristics due to blood components.

Next, specific configuration examples of the light emitting unit 21 and the light receiving unit 22 will be described with reference to FIG.
First, a configuration example of the light emitting unit 21 will be described with reference to FIG.
FIG. 3 shows a conventional pulse oximeter and a light emitting unit of an optical pulse wave meter that suppresses measurement errors caused by the movement of the human body using a plurality of different wavelengths, that is, has improved body motion resistance. It is a figure which shows the example of a structure.

The light emitting unit 21 shown in FIG. 3 is a configuration example using a plurality (two) of monochromatic LEDs that emit monochromatic light of only a specific wavelength light that is generally used as a light emitting element.
As shown in FIG.
A red LED 72 emitting red light of about 665 nm (red);
An infrared LED 73 that emits infrared light of about 880 nm (infrared),
With these two single color LEDs.
The switch circuit 71 selectively emits these two monochromatic LEDs and irradiates the living tissue (skin) 30.

FIG. 4 is an example of the emission spectrum distribution of the two monochromatic LEDs used in FIG. FIG. 4 shows the following two emission spectrum distributions.
(A) Emission spectrum distribution of red LED 72 emitting red light of about 665 nm (red) shown in FIG. 3 (b) Emission of infrared LED 73 emitting infrared color light of about 880 nm (infrared) shown in FIG. Spectral distribution As shown in this figure, in general, a pulse oximeter uses 665 nm (red) and 880 nm (infrared).

Next, a configuration example of the light receiving unit 22 will be described with reference to FIG. The light receiving unit 22 inputs, for example, transmitted light or reflected light of the human body with respect to the irradiation light from the light emitting unit 21 having the configuration shown in FIG.
FIG. 5 shows a conventional pulse oximeter or a configuration of the light receiving unit 22 of the optical pulse wave meter that suppresses measurement errors caused by the movement of the human body by using a plurality of wavelengths, that is, has improved resistance to body movement. It is a figure which shows an example.

The light receiving unit 22 shown in FIG. 5 has a configuration using a photodiode (PD) 81 that is generally used as a light receiving element.
Since the photocurrent obtained by the transmitted light or reflected light of the living tissue (skin) 30 constituting the human body is weak, a circuit (an operational amplifier) that converts it into a voltage and amplifies it is necessary.

The light receiving unit 22 shown in FIG. 5 emits light output from the photodiode (PD) 81 in accordance with the light emission switching timing of the red LED 72 and the infrared color LED 73 which are the light emitting elements of the light emitting unit 21 shown in FIG. The current is switched by the switch circuit 82.

That is, the switch circuit 82
An electrical signal corresponding to the light reception signal corresponding to the light emission of the red LED 72 is output to the amplifying unit 83,
An electrical signal corresponding to the light reception signal corresponding to the light emission of the infrared LED 73 is output to the amplifying unit 84.
The switch circuit 82 executes switching control for executing these two outputs without error.

The two outputs switched and output by the switch circuit 82 are distributed to the operational amplifiers of the

amplifiers

83 and 84 and output. Further, in order to prevent a decrease in the output voltage of the operational amplifier at the time of opening due to switching, a hold circuit for holding the voltage up to that time at the time of opening is required for each of the amplifying

units

83 and 84.

As described above, the conventional optical blood flow detection device alternately emits a plurality of light sources, and distributes a light reception signal obtained from a light receiver such as a photodiode to an amplification circuit according to a light emission timing, so that each wavelength is obtained. Measurement of transmitted light or reflected light has been realized. This requires a plurality of light sources, and a circuit that illuminates them alternately and distributes the received light signals in accordance with the timing is complicated, and the structure is complicated.

[2. Configuration and processing of signal processing apparatus for performing optical blood flow analysis of present disclosure]
Next, the configuration and processing of the signal processing device that executes the optical blood flow analysis of the present disclosure will be described.
FIG. 6 is a diagram illustrating an overall configuration example of a signal processing device that executes the optical blood flow analysis of the present disclosure. The signal processing device 100 shown in FIG. 6 has the same configuration as the optical blood flow detection device 20 described above with reference to FIG. That is, the signal processing apparatus 100 shown in FIG.
Light emitting unit 101,
Light receiving unit 102,
Amplifying unit 103,
Signal processing unit 104,
Have

Light is emitted from the light emitting unit 101 to the living tissue 130 having a human blood vessel.
The transmitted light or reflected light of the biological tissue 130 including blood vessels is input to the light receiving unit 102.
An electric signal based on the detection light of the light receiving unit 102 is input to the amplifying unit 103 and amplified.
The electric signal of the amplifying unit 103 is input to the signal processing unit 104, for example, signal processing such as noise removal and waveform shaping is executed, and a biological signal 150 as a measurement result is output.

(2-1. Configuration and Processing of Light Emitting Unit of Signal Processing Device that Performs Optical Blood Flow Analysis of Present Disclosure)
Next, the configuration and processing of the light emitting unit 101 of the signal processing apparatus 100 of the present disclosure will be described.
FIG. 7 is a diagram illustrating a configuration example of the light emitting unit 101 of the signal processing device 100 according to the present disclosure.
The light emitting unit 101 illustrated in FIG. 7 includes a white LED 201 and irradiates the living tissue (skin) 130 with light emitted from the white LED 201.

The white LED 101 is a light emitting unit that simultaneously projects light having a plurality of wavelengths. A light emitting unit 101 illustrated in FIG. 7 uses a white LED 201 as a light emitting element.
FIG. 8 is a diagram showing an example of the emission spectrum distribution of the white LED 201 of the light emitting unit 101 shown in FIG.
As shown in FIG. 8, the white LED 201 has a plurality of peak wavelengths in the emission spectrum distribution. In this example, it has two peaks of 450 nm (blue) and 650 nm (red).

As can be understood by comparing the conventional light emitting unit 21 shown in FIG. 3 with the light emitting unit 101 according to the present disclosure shown in FIG.
The conventional light emitting unit 21 shown in FIG. 3 has two single-color LEDs that emit light of different wavelengths, that is,

LEDs

72 and 73.
On the other hand, the light emitting unit 101 according to the present disclosure shown in FIG. 7 includes a single white LED 201 that emits light including light of multiple wavelengths.
As described above, the light emitting unit 101 according to the present disclosure illustrated in FIG. 7 has a configuration in which a single light source outputs a plurality of wavelengths at the same time, compared to the configuration of the light emitting unit 21 illustrated in FIG. 3 that requires a switching circuit. It has a very simple configuration.

(2-2. Configuration and Processing of Light Receiving Unit of Signal Processing Device that Performs Optical Blood Flow Analysis of Present Disclosure)
Next, the configuration and processing of the light receiving unit 102 of the signal processing apparatus 100 according to the present disclosure will be described.
FIG. 9 is a diagram illustrating a configuration example of the light receiving unit 102 of the signal processing device 100 of the present disclosure. The light receiving unit 102 of the signal processing device 100 of the present disclosure is a light receiving unit that can detect the intensity of light having a plurality of frequencies.

9 uses a two-color light emitting LED as a light receiving element. Usually, an LED is used as a light-emitting element, but since a photovoltaic power is generated during light reception, it can be used as a light-receiving element with a very narrow band. Further, the two-color light emitting LED is generally widely used and has an advantage that it can be used at low cost. However, since the photoelectromotive force at the time of receiving light is weak, it is necessary to amplify by an amplifier circuit (op-amp).

The light receiving unit 102 shown in FIG. 9 has a configuration using a two-color light emitting LED having a blue photodiode (blue PD) 301 and a red photodiode (red PD) 302.
The blue photodiode (blue PD) 301 outputs a signal corresponding to the intensity of the blue wavelength component included in the light reception signal, and the red photodiode (red PD) 302 corresponds to the intensity of the red wavelength component included in the light reception signal. Output the signal.
The output of the blue photodiode (blue PD) 301 is output to and amplified by an amplifying unit 303 composed of an operational amplifier. The output of the amplifying unit 303 is output as a blue light amount signal.
In addition, the output of the red photodiode (red PD) 302 is output to and amplified by an amplifying unit 304 composed of an operational amplifier. The output of the amplifying unit 304 is output as a red light amount signal.

It is desirable that the light receiving unit can receive the light projected from the light emitting unit through the same path in the living tissue. For this reason, a two-color LED capable of receiving light at one place is suitable for this purpose.

(2-3. Regarding Configuration and Processing of Signal Processing Unit of Signal Processing Device that Performs Optical Blood Flow Analysis of Present Disclosure)
As can be understood by comparing the configuration of the conventional light receiving unit 22 described above with reference to FIG. 5 and the light receiving unit 102 in the apparatus of the present disclosure described with reference to FIG. 9, refer to FIG. The light receiving unit 102 of the present disclosure described above does not require a switch circuit or a hold circuit, and has a simple configuration.

The apparatus of the present disclosure has a configuration in which the light emitting unit 101 described with reference to FIG. 7 and the light receiving unit 102 described with reference to FIG. 9 are combined. The light receiving unit 102 receives the reflected light or transmitted light of the light emitted from the light emitting unit 101 onto the living tissue including the blood vessels of the human body. By analyzing the received light signal, it is possible to detect the pulse wave component of arterial blood based on the increase or decrease of the received light amount.

A configuration example of the signal processing unit 104 of the signal processing apparatus 100 illustrated in FIG. 6 is illustrated in FIG.
As illustrated in FIG. 6, the signal processing unit 104 includes a noise removal unit 501, a pulse detection unit 502, and an oxygen concentration detection unit 503.

The blue light obtained by amplifying the light receiving signal of the blue photodiode (blue PD) 301 of the light receiving unit 102 and the light receiving signal of the red photodiode (red PD) 302 of the light receiving unit 102 shown in FIG. The amplified red light outputs an electrical signal corresponding to each light quantity, that is, a blue light signal 411 and a red light signal 412 shown in the figure to the noise removing unit 501.

The noise removing unit 501 performs processing for removing noise included in the blue light signal 411 and the red light signal 412. The noise is, for example, noise caused by the movement of a person who is a measurer, that is, noise caused by body movement, and is characterized by irregularity common to two signals, that is, the blue light signal 411 and the red light signal 412. Included as a fluctuation signal. By analyzing the two signals, it is possible to remove noise by removing irregular common fluctuation signals. There are various noise removal methods. For example, a method of obtaining a difference by multiplying a preset coefficient is used.

The noise-removed blue signal 431 and the noise-removed red signal 432 from which noise has been removed by the noise removing unit 501 are output to the pulse detecting unit 502 and the oxygen concentration detecting unit 503.
The pulse detection unit 502 detects a pulse by analyzing regular fluctuations in at least one of the noise-removed blue signal 431 and the noise-removed red signal 432.
That is, the regular wave described above with reference to FIG. 1B is acquired, and the pulse 511 is detected and output based on the acquired wave.

Further, the oxygen concentration detection unit 503 detects the oxygen concentration in the bloodstream based on the correspondence relationship between the noise-removed blue signal 431 and the noise-removed red signal 432.
FIG. 11 is a graph showing measurement data of a pulse oximeter using a difference in light absorption characteristics between oxygenated hemoglobin and reduced hemoglobin in blood.
That is, it is a graph showing the difference in light absorption characteristics between oxygenated hemoglobin (HbO2), which is hemoglobin having oxygen in blood, and reduced hemoglobin (Hb), which is hemoglobin not having oxygen. In the figure, the horizontal axis represents the wavelength (Wave Length (nm)), and the vertical axis represents the absorbance (Absorption).

The solid line shows the absorbance corresponding to the light wavelength of oxygenated hemoglobin (HbO2), which is oxygen-containing hemoglobin,
The dotted line indicates the absorbance corresponding to the light wavelength of reduced hemoglobin (Hb), which is hemoglobin having no oxygen.

The wavelength of each color is
Blue light is about 440nm,
Red light is about 660 nm,
Infrared light is about 880 nm,
It is.

The apparatus configuration of the present disclosure described with reference to FIGS. 6 to 10 receives blue light of about 440 nm and red light having a height of about 660 nm as transmitted light or reflected light of blood vessels.
Therefore, when there is a lot of oxygen in the blood, the relationship corresponding to the solid line (HbO2) shown in FIG. 11, for example, the absorbance corresponding to the two wavelength lights shown in the figure,
Absorbance corresponding to blue light of about 440 nm (a1),
Absorbance corresponding to red light of about 660 nm (a2),
It is measured as a blue light signal and a red light signal having an intensity reflecting these absorbances.

On the other hand, when there is little oxygen in the blood, the relationship corresponding to the dotted line (Hb) shown in FIG. 11, for example, the absorbance corresponding to the two wavelength lights shown in the figure,
Absorbance corresponding to blue light of about 440 nm (b1),
Absorbance corresponding to red light of about 660 nm (b2),
It is measured as a blue light signal and a red light signal having an intensity reflecting these absorbances.

Thus, the intensity ratio of the blue light signal and the red light signal varies according to the oxygen concentration in the blood.
The oxygen concentration detection unit 503 holds a table storing the correspondence relationship between the intensity ratio of the blue light signal and the red light signal and the oxygen concentration in the memory, and the noise input from the noise removal unit 501 with reference to this table The oxygen concentration 512 is detected and output according to the signal intensity of the removed blue signal 431 and the noise-removed red signal 432.

In addition, it is good also as a structure which calculates oxygen concentration 512 by the calculation prescribed | regulated instead of a table.
That is, the oxygen concentration 512 may be calculated by arithmetic processing using a function that calculates the oxygen concentration using the noise-removed blue signal 431 and the noise-removed red signal 432 as input parameters.

In the configuration using the light emitting unit 21 shown in FIG. 3 and the light receiving unit 22 shown in FIG. 5 described above as the conventional configuration, a configuration for detecting the oxygen concentration using the intensity ratio of red light and infrared light. It is. In this case, the intensity ratio between red light and infrared light is a relationship reflecting the absorbances (a2) and (a3) or (b2) and (b3) shown in FIG. The oxygen concentration is measured from this relationship.

Note that the oxygen concentration measurement process based on the correspondence between the absorbance and the oxygen concentration corresponding to a plurality of lights having different wavelengths is described in, for example, US Pat. Konishi, T. Kisanuki, A. Yamanishi, Y. Majima: Photo Electric Oximeter, US Patent, Patent Number: 3998550, 1976 can be applied.

(2-4. Configuration and Processing Features and Advantages of Signal Processing Device of Present Disclosure)
As explained in the above embodiment,
In the apparatus of the present disclosure, as described with reference to FIG. 7, the white LED 201 that emits light including the wavelength of blue light (about 440 nm) to red light (about 660 nm) is used as the light emitting unit 101.
Further, as shown in FIG. 9, a blue photodiode (blue PD) 301 that outputs a light reception signal corresponding to blue light (about 440 nm) and a red light that outputs a light reception signal corresponding to red light (about 660 nm) as the light receiving unit 102. A photodiode (red PD) 302 was used.

Thus, by making the light emitting unit 101 a single LED capable of outputting a plurality of wavelengths of light, it becomes possible to concentrate measurement points in one place, and from different positions as described with reference to FIG. High-precision measurement is possible compared to a configuration that outputs light of different wavelengths.
For example, by concentrating the measurement points at one point, it is possible to accurately detect noise caused by body movement, and high-accuracy noise removal is realized. Furthermore, by using the measurement result at the same point, it is possible to improve the accuracy of the oxygen concentration measurement according to the absorbance characteristic described with reference to FIG.

In the above-described embodiment, the white LED 201 that emits light including the wavelength of blue light (about 440 nm) to red light (about 660 nm) is used as a single LED of the light emitting unit. It is good also as a structure using the single LED which light-emits the light containing the wavelength of infrared light (about 880 nm) from 660 nm. In this case, on the light receiving side, a red photodiode (red PD) that outputs a received light signal corresponding to red light (about 660 nm) and an infrared photodiode (that outputs a received light signal corresponding to infrared light (about 880 nm)) ( Infrared light PD) is used. The oxygen concentration can be detected by analysis based on the difference in absorbance characteristics between the red light and the infrared light.

In addition, a single-color LED that emits blue to infrared light may be used for the light emitting unit, and a blue diode and an infrared diode may be set for the light receiving unit.
As described above, as the light emitting unit, a single LED that emits light including light of various two or more different wavelengths can be used. In the light receiving unit, the light emission signal of the single LED used for the light emitting unit can be used. It is possible to use various configurations having a plurality of light receiving elements, for example, photodiodes, that detect and output light of different wavelengths contained therein.

Further, as the processing of the oxygen concentration detection unit 503 of the signal processing unit 104, the pulse oximeter using the difference in the absorption characteristics of oxygenated hemoglobin and reduced hemoglobin in the blood shown in FIG. 11 has been described. Not only the oxygen concentration detection process but also a configuration in which blood component measurement using the light absorption characteristics of other blood components is possible.

As described above, in the signal processing device of the present disclosure, the light emitting unit is realized by a single light emitting element. Further, switching of light emission and distribution of received light signals are not required, and a simple signal processing device, that is, a pulse wave detection device or a pulse oximeter, that consumes less current than the conventional technology can be realized.

[3. Summary of composition of the present disclosure]
As described above, the embodiments of the present disclosure have been described in detail with reference to specific embodiments. However, it is obvious that those skilled in the art can make modifications and substitutions of the embodiments without departing from the gist of the present disclosure. In other words, the present invention has been disclosed in the form of exemplification, and should not be interpreted in a limited manner. In order to determine the gist of the present disclosure, the claims should be taken into consideration.

The technology disclosed in this specification can take the following configurations.
(1) a light-emitting unit composed of a single light-emitting element that outputs an optical signal including light of a plurality of different wavelengths;
A light receiving unit that receives transmitted light or reflected light through a human body of a light emission signal of the light emitting unit, each of which includes a plurality of light receiving elements that output light reception signals corresponding to different wavelength light; and
A signal processing apparatus comprising: a signal processing unit that executes signal processing based on light reception signals of a plurality of different wavelength lights output from the light receiving unit.

(2) The signal processing device according to (1), wherein the light emitting unit includes a white LED as the single light emitting element.
(3) The signal processing device according to (2), wherein the white LED is a light emitting element that outputs light having a plurality of different wavelengths including red light and blue light.
(4) The white LED is a light emitting element that outputs light having a plurality of different wavelengths including red light from blue light, and has light having a relative intensity having peaks in the wavelength range of red light and the wavelength range of blue light. The signal processing device according to (2) or (3), wherein the signal processing device is a light-emitting element that outputs.

(5) The signal processing device according to any one of (1) to (4), wherein the light receiving unit includes a plurality of color light emitting LEDs each having a plurality of photodiodes that selectively receive light of different wavelengths.
(6) The signal processing device according to any one of (1) to (5), wherein the light receiving unit includes a blue photodiode and a red photodiode as the plurality of light receiving elements.
(7) The blue photodiode outputs a signal according to the intensity of the blue wavelength component included in the light reception signal, and the red photodiode outputs a signal according to the intensity of the red wavelength component included in the light reception signal. The signal processing device according to (6).

(8) The signal processing unit receives an electric signal based on a received light signal corresponding to a plurality of different wavelength lights, removes noise caused by body movement, and executes signal analysis based on the noise removal signal (1 ) To (7).
(9) The signal processing device according to any one of (1) to (8), wherein the signal processing unit includes a pulse detection unit that detects a pulse according to an output of the light receiving unit.

(10) The signal processing device according to any one of (1) to (9), wherein the signal processing unit includes an oxygen concentration detection unit that detects a blood oxygen concentration according to an output of the light receiving unit.
(11) The signal processing apparatus according to (10), wherein the oxygen concentration detection unit performs blood oxygen concentration detection based on a comparison of signal intensities of detection signals of light having different wavelengths.

Further, the series of processing described in the specification can be executed by hardware, software, or a combined configuration of both. When executing processing by software, the program recording the processing sequence is installed in a memory in a computer incorporated in dedicated hardware and executed, or the program is executed on a general-purpose computer capable of executing various processing. It can be installed and run. For example, the program can be recorded in advance on a recording medium. In addition to being installed on a computer from a recording medium, the program can be received via a network such as a LAN (Local Area Network) or the Internet and installed on a recording medium such as a built-in hard disk.

In addition, the various processes described in the specification are not only executed in time series according to the description, but may be executed in parallel or individually according to the processing capability of the apparatus that executes the processes or as necessary. Further, in this specification, the system is a logical set configuration of a plurality of devices, and the devices of each configuration are not limited to being in the same casing.

As described above, according to the configuration of an embodiment of the present disclosure, an optical blood flow measurement device that realizes a simple configuration and processing is realized.
Specifically, a light emitting unit that outputs an optical signal including light of a plurality of different wavelengths, and a light receiving unit that receives transmitted light or reflected light through the human body of the light emission signal of the light emitting unit, and light having a plurality of different wavelengths A light receiving unit that selectively receives light and a signal processing unit that performs signal processing on an electrical signal corresponding to a light reception signal of the light receiving unit. The light emitting unit includes a white LED as a light emitting element, the light receiving unit includes a blue photodiode and a red photodiode, and the signal processing unit outputs an electric signal based on a light receiving signal corresponding to a plurality of different wavelength lights. Inputs noise removal caused by body movement, blood oxygen concentration detection signal, etc.

DESCRIPTION OF SYMBOLS 10 Human body 11 Arterial blood layer 12 Venous blood layer 13 Tissues other than blood 20 Optical blood flow detection device 21 Light emitting unit 22 Light receiving unit 23 Amplifying unit 24 Signal processing unit 30 Biological tissue 50 Biological signal 71 Switch circuit 72 Red LED
73 LED outside red
DESCRIPTION OF SYMBOLS 100 Optical blood-flow detection apparatus 101 Light-emitting part 102 Light-receiving part 103 Amplifying part 104 Signal processing part 130 Biological tissue 150 Biological signal 201 White LED
301 blue photodiode 302 red photodiode 303 amplifying unit 304 amplifying unit 411 blue light signal 412 red light signal 431 noise removing blue high signal 432 noise removing red high signal 501 noise removing unit 502 pulse detecting unit 503 oxygen concentration detecting unit 511 pulse 512 Oxygen concentration

Claims

A light-emitting unit composed of a single light-emitting element that outputs an optical signal including light of a plurality of different wavelengths;
A light receiving unit that receives transmitted light or reflected light through a human body of a light emission signal of the light emitting unit, each of which includes a plurality of light receiving elements that output light reception signals corresponding to different wavelength light; and
A signal processing apparatus comprising: a signal processing unit that executes signal processing based on light reception signals of a plurality of different wavelength lights output from the light receiving unit.
The signal processing apparatus according to claim 1, wherein the light emitting unit includes a white LED as the single light emitting element.
3. The signal processing apparatus according to claim 2, wherein the white LED is a light emitting element that outputs light of a plurality of different wavelengths including red light and blue light.
The white LED is a light emitting element that outputs light of a plurality of different wavelengths including red light from blue light, and outputs light having a relative intensity having a peak in the wavelength region of red light and the wavelength region of blue light. The signal processing apparatus according to claim 2, wherein the signal processing apparatus is a light emitting element.
The signal processing apparatus according to claim 1, wherein the light receiving unit is configured by a multi-color light emitting LED having a plurality of photodiodes that selectively receive light of different wavelengths.
The signal processing device according to claim 1, wherein the light receiving unit includes a blue photodiode and a red photodiode as the plurality of light receiving elements.
The blue photodiode outputs a signal corresponding to the intensity of the blue wavelength component included in the received light signal,
The signal processing apparatus according to claim 6, wherein the red photodiode outputs a signal corresponding to an intensity of a red wavelength component included in a light reception signal.
2. The signal processing unit according to claim 1, wherein the signal processing unit inputs an electric signal based on a light reception signal corresponding to a plurality of different wavelength lights, removes noise caused by body movement, and performs signal analysis based on the noise removal signal. Signal processing device.
The signal processing device according to claim 1, wherein the signal processing unit includes a pulse detection unit that performs pulse detection according to an output of the light receiving unit.
The signal processing apparatus according to claim 1, wherein the signal processing unit includes an oxygen concentration detection unit that detects a blood oxygen concentration according to an output of the light receiving unit.
The signal processing apparatus according to claim 10, wherein the oxygen concentration detection unit performs blood oxygen concentration detection based on a comparison of signal intensities of detection signals of light having different wavelengths.
A signal processing method executed in a signal processing device,
A light emitting step in which the light emitting unit outputs an optical signal including light of a plurality of different wavelengths from a single light emitting element;
The light receiving unit is a light receiving step for receiving transmitted light or reflected light through the human body of the light emission signal of the light emitting unit, and each of the plurality of light receiving elements that output light reception signals corresponding to different wavelength light has different wavelength light A light receiving step for generating a light receiving signal of
A signal processing method for executing a signal processing step in which a signal processing unit executes signal processing based on light reception signals of a plurality of different wavelength lights output from the light receiving unit.