JP7703112B2 - Vital information measuring device, vital information measuring method, biological management system, and biological management method - Google Patents

Description

The disclosed technology relates to a vital information measuring device, a vital information measuring method, a biological management system, and a biological management method.

A technology is known that aims to provide a so-called everyday health check-up by collecting various information (hereafter referred to as "vital information") that is an indicator of a user's health condition by detecting biological substances contained within the user's body without the user being aware of it while they go about their daily lives, and providing the user with unobtrusive feedback on their health condition as they go about their daily lives.

For example, Patent Document 1 discloses a smart toilet system equipped with a sensor chip that detects biological substances as an example of technology aimed at daily health checkups.

International Publication No. 2016/129087

In a biomedical management system using a vital information measuring device, such as the smart toilet system exemplified in Patent Document 1, the collected vital information can be fed back not only to the user but also to medical institutions. However, the business of using a biomedical management system to feed back a user's vital information to medical institutions has not actually taken off. One possible reason for this lack of popularity is that there is an insufficient mechanism for preventing the leakage of personal information about users.

The disclosed technology aims to provide a biometric management system and method that are, in principle, robust against the leakage of personal information.

The vital information measuring method according to the disclosed technology is a vital information measuring method for a vital information measuring device having a first optical system with a wavelength range of 800 nm to 950 nm and a second optical system whose wavelength range includes 1600 nm, and includes a first step of detecting an image including a blood vessel shape using the first optical system, a second step of aligning the image obtained by the first optical system with the image obtained by the second optical system, a third step of extracting a portion of the image obtained by the second optical system that corresponds to the position of the blood vessels, and a fourth step of calculating HbA1c based on the image information extracted in the third step.

The biometric management system of the disclosed technology includes a vital information measuring device having the above-mentioned configuration, and is therefore, in principle, robust against the leakage of personal information.

FIG. 1 is an explanatory diagram showing the configuration of a biological management system according to the first embodiment. FIG. 2 is an explanatory diagram showing the configuration of the vital information measuring device according to the first embodiment. FIG. 3 is an explanatory diagram showing a modified example of the configuration of the vital information measuring device according to the first embodiment. FIG. 4 is a flow diagram showing processing steps of the vital information measuring method according to the first embodiment. FIG. 5 is an explanatory diagram showing the data structure of data obtained by the disclosed technique. FIG. 6 is a diagram for explaining the processing performed by the processing circuitry 150 on the images (images 1-3) handled by the vital information measuring device according to the disclosed technique. FIG. 7 is a graph showing the pixel brightness values (average brightness values) as a histogram after the finger image cutout process for image 1-3 in FIG. FIG. 8 is a graph showing pixel brightness values as a histogram (indicating maximum brightness peaks) after the finger image is cut out from image 1-3 in FIG. FIG. 9 is an explanatory diagram showing the configuration of a vital information measuring device according to the second embodiment. FIG. 10 is a diagram illustrating an example of a luminance histogram of an image. FIG. 11 is an image diagram showing the display content of a vital information measuring device according to embodiment 3.

Simply put, this disclosed technology is a technology that studies human blood vessels scientifically, combines highly accurate personal authentication with healthcare, and contributes to preventive medicine.

Embodiment 1.
FIG. 1 is an explanatory diagram showing the configuration of a biological management system 1000 according to the first embodiment.
1, the biological management system 1000 according to the first embodiment is composed of a vital information measuring device 100 and a medical institution side data management device 200. The vital information measuring device 100 and the medical institution side data management device 200 are connected via the Internet.

FIG. 2 is an explanatory diagram showing the configuration of the vital information measuring device 100 according to the first embodiment.
As shown in FIG. 2, the vital information measuring device 100 according to the first embodiment includes an inner holder 102, a finger detection unit 104 (104-1, 104-2), a first light source 110 (110-1, 110-2), a first light source filter 112, a first light source collecting lens 114, a first light source area sensor 116, a second light source 120, a second light source filter 122, a second light source collecting lens 124, a second light source area sensor 126, and a processing circuit 150.
In the vital information measuring device 100, the first light source 110, the first light source filter 112, the first light source condenser lens 114, and the first light source area sensor 116 configure a first optical system.
In the vital information measuring device 100, the second light source 120, the second light source filter 122, the second light source collective lens 124, and the second light source area sensor 126 configure a second optical system.

2 represents a user's finger. In this manner, the vital information measurement device 100 according to the present disclosure is designed to be used by the user by inserting his/her finger.
The manner in which the user inserts his or her finger into the hole for use is the same as the use of a "biometric authentication key" that uses information on the shape pattern of blood vessels (hereinafter simply referred to as "blood vessel shape") as a key for the front door of a residence. The vital information measuring device 100 according to the present disclosure can continuously measure vital information without the user being aware of it during a casual daily action such as unlocking the front door of the user's home.
The use of the biometric authentication key by inserting a finger into the hole is not limited to the use at the entrance of a house. The biometric authentication key can be used in a wide range of applications, such as at the entrance of an apartment building, at the entrance of an office, in passenger vehicles such as cars, buses, and taxis, and for managing bank accounts.

FIG. 3 is an explanatory diagram showing a modified example of the configuration of the vital information measuring device 100 according to the first embodiment.
The vital information measuring device 100 shown in FIG. 3 includes a beam splitter 130 in addition to the components shown in FIG.
As shown in FIG. 3, the vital information measuring device 100 according to the present disclosed technique may use a beam splitter 130 that splits the path of light into a first optical system and a second optical system.
Furthermore, in the vital information measuring device 100, a coating that realizes the function of a wavelength selection filter may be applied to the reflective surface and the transmissive surface of the beam splitter 130. By applying the coating, the first light source filter 112 and the second light source filter 122 can be omitted.
Furthermore, the vital information measuring device 100 may use a movable mirror instead of the beam splitter 130. The vital information measuring device 100 may, for example, alternately turn on the first light source 110 and the second light source 120, and selectively switch the optical path to one corresponding to the light source using a movable mirror to measure images of the first optical system and the second optical system in time series rather than simultaneously. One of the effects of using a movable mirror is that it can eliminate light attenuation that occurs in the beam splitter 130.

<<Vital Information Measuring Device 100>>
The vital information measuring device 100 according to the first embodiment has at least the following two functions. The first function is to measure the shape of blood vessels that run through the inserted user's finger. The second function is to measure vital information, such as HbA1c (hemoglobin A1c) in the blood, for the inserted user's finger.
The first action is mainly realized by the first optical system in the vital information measuring device 100. The first action mainly realized by the first optical system realizes a function as a biometric authentication key, which is called blood flow authentication, vein authentication, or the like.
The second function is mainly realized by the second optical system in the vital information measuring device 100. The second function mainly realized by the second optical system realizes a function as a non-invasive measuring device for vital information.

<<Inner Holder 102>>
The inner holder 102 is a part inside the housing of the vital information measuring device 100, and is a component for keeping the user's fingers in the same position and posture during use.
2 and 3, the portion marked "gap" represents a feature of the shape of the inner holder 102, that is, a gap is provided between the inner holder 102 and the finger. By providing a gap between the inner holder 102 and the finger, the blood vessels of the finger are not compressed, and it is possible to capture a clearer image of the shape of the blood vessels running throughout the finger. The provision of a gap between the inner holder 102 and the finger is particularly effective for users (women, children, etc.) with thin blood vessels.
2 and 3, the portions marked "space" represent a feature of the shape of the inner holder 102, that is, a space is provided at the corresponding portion of the inner holder 102. With this design, even if the fingernails are long or if the fingernails are artificial, the fingernails do not hit the inner holder 102, and the finger can be kept in the same position and posture.

The inner holder 102 also has the function of blocking unnecessary light from the outside. If unnecessary light enters from the outside, it becomes difficult to obtain an image for achieving the purpose of the disclosed technology in the first light source area sensor 116 and the second light source area sensor 126 described below. If the light is not sufficiently blocked, it becomes difficult to extract the outline of the finger in particular in the first light source area sensor 116 and the second light source area sensor 126 described below, and an image with the desired contrast cannot be obtained. Therefore, the inner holder 102 may be configured to have a light-shielding sheet on the back of the finger. The light-shielding sheet to be adopted may be selected by determining the performance such as absorbance from the viewpoint of the degree of extraction of the outline of the finger and whether the contrast is the one that is originally desired.

<<Finger detection unit 104 (104-1, 104-2)>>
The finger detection unit 104 (104-1, 104-2) is a component that detects the user's finger inserted into the inner holder 102. As shown in FIG. 2 and FIG. 3, the finger detection unit 104 may be composed of at least two elements, a part that corresponds to the so-called back of the finger (finger detection unit 104-1) and a part that corresponds to the tip of the finger (finger detection unit 104-2). For example, the finger detection unit 104 may measure the capacitance by causing a weak current to flow between the finger detection unit 104-1 and the finger detection unit 104-2. By measuring the capacitance, the finger detection unit 104 can distinguish between the case where an inorganic object such as a ballpoint pen is inserted into the inner holder 102 and the case where a human finger is inserted.

<<First light source 110 constituting the first optical system>>
The first light source 110 constituting the first optical system is a light source for measuring the shape of blood vessels that are spread throughout the finger. Specifically, the first light source 110 constituting the first optical system is preferably one that emits near-infrared rays (NIR) in a wavelength range of 800 [nm] to 950 [nm]. More preferably, the first light source 110 is preferably one that emits near-infrared rays (NIR) in a wavelength range of 840 [nm] to 950 [nm]. The first light source 110 in the first optical system is preferably realized by, for example, an LED (Light Emitting Diode).
As shown in Figures 2 and 3, the first light source 110 (110-1, 110-2) may be configured with a plurality of light sources so that light can be irradiated onto the entire finger. Although two first light sources 110 (110-1, 110-2) are shown in Figures 2 and 3, the disclosed technology is not limited to this. The number of first light sources 110 (110-1, 110-2, ...) according to the first embodiment may be two or more.
2 and 3, the first light source 110 (110-1, 110-2) is preferably disposed in the inner holder 102 so as to contact the so-called back side (outer side) of the finger to be measured. In this manner, contact between the light source and the finger contributes to obtaining a clear image in the first light source area sensor 116 described below.
2 and 3, a figure labeled "circuit board" represents a board such as a PCB (Printed Circuit Board). The first light sources 110 (110-1, 110-2, ...) are mounted on a board such as a PCB.

<<First Light Source Filter 112 Constituting the First Optical System>>
The first light source filter 112 constituting the first optical system is an optical filter that selectively passes only infrared (IR) light that is emitted from the first light source 110 and passes through the finger that is the measurement target. In other words, the first light source filter 112 constituting the first optical system may be any filter that has the property of passing light in the wavelength range of 800 [nm] to 950 [nm] and blocking light in the wavelength range of 1500 [nm] to 1700 [nm] of the second light source 120 described later.

<<First light source condenser lens 114 constituting the first optical system>>
The first light source condenser lens 114 constituting the first optical system is an optical lens that condenses near infrared (NIR) light that has passed through the first light source filter 112. The arrangement of each of the components is determined so that the focal point of the first light source condenser lens 114 is aligned with the light receiving portion of the first light source area sensor 116, which will be described later. By arranging them in this manner, the first light source area sensor 116 can detect an image of blood vessels that are distributed throughout the finger.

<<First light source area sensor 116 constituting the first optical system>>
The first light source area sensor 116 constituting the first optical system is a component that detects an image of blood vessels that run through the finger. Specifically, the first light source area sensor 116 constituting the first optical system is an area sensor such as a CMOS image sensor (Complementary Metal Oxide Semiconductor) that has high sensitivity to near infrared rays. More preferably, the first light source area sensor 116 is a CMOS image sensor whose spectral sensitivity characteristic has a peak near 850 [nm]. The CMOS image sensor is sometimes called a CMOS camera.

Second Light Source 120 Constituting the Second Optical System
The second light source 120 constituting the second optical system is a light source for measuring HbA1c in blood for the inserted finger of the user. The second light source 120 constituting the second optical system is selected to emit infrared light with a longer wavelength than the first light source 110, specifically, a wavelength range of 1500 [nm] to 1700 [nm]. The reason why the wavelength range of the second light source 120 is selected to be 1500 [nm] to 1700 [nm] is because glucose has the property of absorbing light around 1600 [nm]. Therefore, the second light source 120 may be selected so that its wavelength range includes 1600 [nm]. The second light source 120 constituting the second optical system may be realized by, for example, an LED, similar to the first light source 110.
2 and 3, the number of second light sources 120 is one, but the technology disclosed herein is not limited to this. The second light source 120 may be configured with a plurality of second light sources 120 so that light can be irradiated onto the entire finger.
2 and 3, the second light source 120 is preferably disposed in the inner holder 102 so as to come into contact with the so-called back side (outer side) of the finger to be measured. Bringing the light source into contact with the finger in this manner contributes to obtaining a clear image in the second light source area sensor 126 described below.
The second light source 120, like the first light source 110, is mounted on a substrate such as a PCB.

<<Second Light Source Filter 122 Constituting the Second Optical System>>
The second light source filter 122 constituting the second optical system is an optical filter that selectively passes only infrared (IR) light that is emitted from the second light source 120 and passes through the finger that is the measurement target. In other words, the second light source filter 122 constituting the second optical system may be any filter that has the property of passing light in the wavelength range of 1500 [nm] to 1700 [nm] and blocking light in the wavelength range of 800 [nm] to 950 [nm] of the first light source 110.

<<Second light source collective lens 124 constituting the second optical system>>
The second optical system includes a second light source collective lens 124, which is an optical lens that collects infrared rays (IR) that have passed through the second light source filter 122. The arrangement of each of the components is determined so that the focal point of the second light source collective lens 124 is aligned with the light receiving portion of the second light source area sensor 126, which will be described later. By arranging the components in this manner, the second light source area sensor 126 can detect an image for measuring HbA1c in blood.

<<Second Light Source Area Sensor 126 Constituting the Second Optical System>>
The second light source area sensor 126 constituting the second optical system is a component that detects an image for measuring HbA1c in blood. Specifically, the second light source area sensor 126 constituting the second optical system is preferably an area sensor equipped with an InGaAs sensor. InGaAs stands for indium gallium arsenide. The InGaAs sensor is a sensor that has high sensitivity in the near-infrared wavelength region from 950 [nm] to 1700 [nm]. The InGaAs sensor is also sometimes called an InGaAs camera.

<<Beam splitter 130>>
The beam splitter 130 is a component that splits the path of light into a first optical system and a second optical system. The vital information measuring device 100 according to the disclosed technology may use an optical element such as the beam splitter 130 as appropriate to configure the device compactly. The beam splitter 130 may be in various forms, such as a polarizing beam splitter, a half mirror, a prism type, a flat type, or a wedge substrate type, and the specific form may be appropriately determined according to the design specifications, etc.

<<Processing circuit 150>>
The processing circuit 150 is a component for controlling the vital information measuring device 100 .
The processing circuitry 150 may be dedicated hardware or a central processing unit (CPU) that executes programs stored in a memory.

When the processing circuit 150 is dedicated hardware, the processing circuit 150 may be an ASIC, an FPGA, etc. In this case, each function of the vital information measuring device 100 is realized by the processing circuit 150, which is an ASIC, an FPGA, etc.
When the processing circuitry 150 is a CPU, each function of the vital information measuring device 100 is realized by software. The software is written as a program and stored in memory. The processing circuitry 150 realizes each function of the vital information measuring device 100 by reading and executing the program stored in the memory.
The processing circuitry 150 may comprise a storage device such as a memory, whether that be dedicated hardware or a CPU executing a program stored in the memory.

<<Processing Steps of Vital Information Measuring Device 100>>
Fig. 4 is a flow diagram showing the processing steps of the vital information measuring method according to embodiment 1. In other words, Fig. 4 is a flow diagram showing the processing steps of the vital information measuring device 100 realized by the processing circuit 150.

The block labeled "ST1" in Figure 4 represents the first step of the vital information measuring method according to embodiment 1, specifically, the step of detecting blood vessel shape. The step of detecting blood vessel shape is mainly achieved by the first optical system and processing circuit 150 of the vital information measuring device 100. In the step of detecting blood vessel shape, the processing circuit 150 performs image processing such as binarization on the detection result of the first light source area sensor 116 to detect the blood vessel shape.

The processing circuit 150 can compare the blood vessel shape detected in the first step with pre-registered data on the user's blood vessel shape to identify the user. This processing step is related to the first action described above, and is a processing step that realizes the function of a biometric authentication key, also known as blood flow authentication, vein authentication, etc. Note that biometric authentication is a technology that utilizes the characteristic that physical characteristics differ from person to person, and identifies whether a person is the person in question by checking pre-registered biometric information data at the time of authentication.

As mentioned above, the shape of a person's blood vessels is an internal physical characteristic and is therefore more stable than a fingerprint, which is an external physical characteristic. However, in the case of a growing child, the shape of the blood vessels may change gradually as the child grows. Therefore, in the first step of detecting the blood vessel shape, the processing circuit 150 may appropriately update the user's blood vessel shape data that has been registered in advance, as necessary.

The block labeled "ST2" in FIG. 4 represents the second step of the vital information measurement method according to the first embodiment, specifically, the step of aligning the image obtained by the first light source area sensor 116 and the image obtained by the second light source area sensor 126. The step of aligning is mainly realized by the processing circuit 150. In the step of aligning, the processing circuit 150 may use, for example, information obtained by a calibration operation performed in advance. In addition, in the step of aligning, the processing circuit 150 may use, for example, characteristic information that is common to both images, such as the outline of a finger, in each of the images obtained by the first light source area sensor 116 and the second light source area sensor 126.

3, by using the beam splitter 130, it becomes possible to virtually place the first light source area sensor 116 and the second light source area sensor 126 at the same position with respect to the position of the finger. Therefore, in consideration of this second step, it can be said that it is preferable to use the beam splitter 130.
Even if the beam splitter 130 is not used, the processing circuitry 150 can perform image processing to achieve alignment by using one of the images as a reference and processing the other image.

In the block labeled "ST2" in FIG. 4, the black circle represents glucose. Glucose is a simple sugar with the molecular formula C ₆ H ₁₂ O ₆ , and is also called grape sugar. As described above, glucose has the property of absorbing light at about 1600 [nm]. Therefore, in the image obtained by the second light source area sensor 126, glycated substances appear black. The disclosed technology utilizes this property to calculate the amount of glycated hemoglobin required to calculate HbA1c.

The block labeled "ST3" in Figure 4 represents the third step of the vital information measuring method according to embodiment 1, specifically, the step of extracting a portion corresponding to the position of a blood vessel in the image obtained by the second light source area sensor 126. The step of extracting a portion corresponding to the position of a blood vessel is mainly realized by the processing circuit 150. In the step of extracting a portion corresponding to the position of a blood vessel, the processing circuit 150 utilizes the alignment information performed in the second step.

The idea of realizing an optical blood glucose measuring device by focusing on the property of glucose absorbing light at around 1600 nm may not be new, but as far as the inventors know, there are no optical blood glucose measuring devices approved as medical devices in Japan.
In order for an optical blood glucose measuring device to be approved as a medical device in Japan, it must have a reliable measurement accuracy. Conventional devices do not have the above-mentioned third step according to the disclosed technology, so the value measured by the sensor is affected by biological tissues other than blood vessels. More specifically, in conventional devices, even if a user's finger is irradiated with light of about 1600 [nm] and an image is taken, the light passing through biological tissues other than blood vessels is also included, so that a problem occurs in that an image with the desired contrast cannot be obtained. It is believed that the influence of biological tissues other than blood vessels is the reason why the measurement accuracy cannot be improved.
The vital information measuring device 100 according to the present disclosed technique performs the above third step in the processing circuit 150, that is, the step of extracting the portion corresponding to the position of the blood vessel, and therefore can improve the measurement accuracy.

式（１）で示されるとおり、ＨｂＡ１ｃは、総ヘモグロビン中、糖化ヘモグロビンがどのくらいの割合で存在しているかを表したものである。なお、一般的に、ＨｂＡ１ｃを表すために、よく、パーセント［％］が用いられる。 The block labeled "ST4" in Fig. 4 represents a fourth step of the vital information measurement method according to the first embodiment, specifically, a step of calculating HbA1c. As shown in Fig. 4, HbA1c is given by the following formula:

As shown in formula (1), HbA1c represents the percentage of glycated hemoglobin in total hemoglobin. In general, HbA1c is often expressed as a percentage [%].

The step of calculating HbA1c is mainly realized by the processing circuit 150. In the step of calculating HbA1c, the processing circuit 150 uses image information obtained by extracting a portion corresponding to the position of blood vessels from the image obtained by the second light source area sensor 126 obtained in the third step. Specifically, the processing circuit 150 estimates the ratio of the amount of glycated hemoglobin to the amount of total hemoglobin shown on the right side of formula (1) based on the image information obtained by extracting the portion corresponding to the position of blood vessels, and calculates HbA1c.

The processing circuit 150 may be configured to include trained artificial intelligence in order to estimate the total hemoglobin amount and the glycated hemoglobin amount from the image information. The artificial intelligence included in the processing circuit 150 may be realized by an artificial neural network such as a convolution neural network (CNN). In addition, the artificial intelligence is not limited to an artificial neural network, and may be realized by a mathematical model that is premised on learning (hereinafter, referred to as a "learning model").
The learning of the artificial intelligence provided in the processing circuit 150 may be in the form of: HbA1c obtained by actually drawing blood and performing a blood test is used as the correct answer label; image information obtained by extracting a portion corresponding to the position of blood vessels from the image obtained by the second light source area sensor 126 is given a correct answer label to be used as teacher data; and supervised learning is performed.

The block labeled "ST5" in Figure 4 represents the fifth step of the vital information measurement method according to embodiment 1, specifically, the step of calculating the blood glucose level. The step of calculating the blood glucose level is mainly realized by the processing circuit 150. In the step of calculating the blood glucose level, the processing circuit 150 uses image information obtained by extracting the portion corresponding to the position of the blood vessel from the image obtained by the second light source area sensor 126, which was obtained in the third step.

The blood glucose level is the concentration of glucose in the blood. The processing circuit 150 may calculate the blood glucose level using the trained artificial intelligence described above.
As in the case of calculating HbA1c, the learning of the artificial intelligence provided in the processing circuit 150 may be in the form of: the blood glucose level obtained by actually drawing blood and performing a blood test is used as the correct answer label; the part corresponding to the position of the blood vessels is extracted from the image obtained by the second light source area sensor 126, and the correct answer label is attached to the image information to be used as teacher data; and supervised learning is performed.

Although not shown in the flow diagram of FIG. 4, the processing circuit 150 may perform a process of feeding back the vital information to the user after the fifth step. Specifically, the process of feeding back the vital information to the user may involve displaying the vital information on a display. The processing circuit 150 may also store normal and abnormal values of the vital information in advance, and, if the measured vital information is an abnormal value, display a message to the user encouraging them to see a doctor.

Figure 5 is an explanatory diagram showing the data structure of data obtained by the disclosed technology. As shown in Figure 5, the data obtained by the disclosed technology is characterized by having a data structure in which biometric authentication information and vital information are integrated. Of the data in the data structure shown in Figure 5, the biometric authentication information is biometric authentication information based on the blood vessel shape obtained in the first step of the vital information measurement method of embodiment 1. Of the data in the data structure shown in Figure 5, the vital information is vital information including HbA1c obtained in the fourth step of the vital information measurement method of embodiment 1 and blood glucose level obtained in the fifth step.

The vital information measuring device 100 according to the present disclosure may be provided with a structure for measuring blood oxygen saturation (SpO2), blood pressure, and pulse rate in addition to HbA1c and blood glucose level. For example, the vital information measuring device 100 according to the present disclosure may be provided with a structure adopted in a pulse oximeter to measure blood oxygen saturation and pulse rate. Specifically, the vital information measuring device 100 according to the present disclosure may be provided with a mechanism for pinching the fingertip of the measurement subject using the principle of a lever in the part where the tip of the finger of the measurement subject comes into contact, that is, the part of the finger detection unit 104-2 in FIG. 2 and FIG. 3, as a structure for measuring blood oxygen saturation and pulse rate.

In the biometric management system 1000 according to the present disclosure, the vital information measuring device 100 transmits data having the data structure shown in FIG. 5 to the medical institution's data management device 200 via the Internet or the like. As described above, the data structure adopted by the present disclosure is a data structure in which biometric authentication information and vital information are integrated, so that the vital information will not be mistaken for that of another user. In other words, the biometric management system 1000 according to the present disclosure can, in principle, reduce the risk of mistaking the vital information for that of another user and provide feedback of the user's vital information to the medical institution.

In order to prevent information leakage, i.e., to prevent a third party from stealing vital information, the disclosed technology encrypts the data handled by the disclosed technology shown in FIG. 5. The biometric management system 1000 according to the disclosed technology can also use two encryption keys (also called "encryption keys") by focusing on the data structure of the data handled by the disclosed technology shown in FIG. 5. That is, the biometric management system 1000 according to the disclosed technology can use one common encryption key for encrypting biometric authentication information and an individual encryption key assigned to each user. The individual encryption key assigned to each user is used to encrypt vital information among the data. These two types of encryption keys are shared between the vital information measuring device 100 and the medical institution side data management device 200.
The vital information measuring device 100, which is the transmitting side of the biometric management system 1000, encrypts the biometric authentication information of one user's data with a common encryption key, and encrypts the vital information with an individual encryption key. The encrypted data is sent to the medical institution's data management device 200 via the Internet.
The medical institution data management device 200, which is the receiving side of the biometric management system 1000, uses a common encryption key to decrypt the biometric authentication information of the transmitted data. The medical institution data management device 200 compares the decrypted biometric authentication information, i.e., the image data of the blood vessel shape, with the blood vessel shape data of preregistered users to identify which user the data belongs to. Next, the medical institution data management device 200 uses an individual encryption key assigned to each user to decrypt the vital information of the data.
In this manner, the method of the disclosed technique using two types of encryption keys, a common encryption key and an individual encryption key, is referred to in this specification as a "two-stage encryption method."

An excellent effect of the vital information measuring device 100 according to the present disclosed technology is that, because the vital information measuring device 100 is equipped with a biometric authentication function, the vital information can be easily linked to the true user (the true owner of the vital information) without any mistake.
As a biometric authentication function, fingerprints, which can also identify an individual based on information about the finger, can also be used. Indeed, fingerprints are an excellent means of identifying an individual in criminal investigations. However, since fingerprints are on the outside of the body, they are easily damaged. For example, fingerprints become shallower when frequently disinfected with alcohol, and when optical detection is performed, the fingerprints are less stable than blood vessel shapes, which are information about the inside of the body.

Another excellent effect of the vital information measuring device 100 according to the disclosed technology is that while it is a non-invasive, human-friendly optical measurement method, it is able to extract the portion corresponding to the position of the blood vessel from the image obtained by the second light source area sensor 126, thereby eliminating the influence of biological tissues other than blood vessels and providing high measurement accuracy.

Another excellent effect of the vital information measuring device 100 according to the disclosed technology is that it allows the user to continuously measure vital information without being aware of it during a casual everyday action such as unlocking the front door of their home.

An excellent effect of the biometric management system 1000 relating to the disclosed technology is that a two-stage encryption method can be adopted for data having a data structure in which biometric authentication information and vital information are integrated, making it, in principle, robust against leakage of personal information.

Embodiment 2.
The vital information measuring device, vital information measuring method, biological management system, and biological management method according to the second embodiment are modified examples of the vital information measuring device, vital information measuring method, biological management system, and biological management method according to the present disclosure. In the second embodiment, the same symbols as those used in the first embodiment are used unless otherwise specified. In the second embodiment, explanations that overlap with the first embodiment are omitted as appropriate.

FIG. 6 is a diagram for explaining the processing performed by the processing circuitry 150 on the images (images 1-3) handled by the vital information measuring device 100 according to the disclosed technique.
As described above, the step of detecting the blood vessel shape is mainly realized by the first optical system and the processing circuit 150 of the vital information measuring device 100. In the step of detecting the blood vessel shape, the processing circuit 150 performs image processing such as binarization on the detection result of the first light source area sensor 116 to detect the blood vessel shape.
Image 1, image 2, and image 3 in FIG. 6 are vascular shapes of a certain subject obtained by the first optical system under different conditions, before image processing such as binarization.
As shown in FIG. 6, processing circuitry 150 performs image processing to remove background information (the solid black areas in images 1-3) and "clip" the finger image.

The finger image cut out from Image 1 is bright overall, and is an example in which the blood flow density has a smaller difference in shading compared to the surrounding area, making it easier to extract the boundary between blood vessels and other areas.
The finger image cut out from image 2 is an example in which the blood flow density is at a reference level of contrast compared to the surrounding area when extracting the boundary between blood vessels and other areas.
The finger image cut out from image 3 is generally dark, and is an example in which the blood flow density has a large difference in shading compared to the surrounding area, which makes it difficult to extract the boundary between blood vessels and other areas.

Fig. 7 is a graph showing pixel brightness values as a histogram (displaying average brightness values) after the finger image extraction process for images 1-3 in Fig. 6. The graph on the left in Fig. 7 is a brightness histogram for the finger image extracted from image 1. The graph in the center in Fig. 7 is a brightness histogram for the finger image extracted from image 2. The graph on the right in Fig. 7 is a brightness histogram for the finger image extracted from image 3.
In each graph in FIG. 7, "X" on the horizontal axis represents the class (brightness value) in the histogram, and "Y" on the vertical axis represents the frequency (number of pixels) in the histogram.
As shown in FIG. 7, the average brightness value for each pixel of the finger image can also be used as an index for determining the gradation of blood flow density.
In the technical field of image processing, the brightness value histogram is sometimes called a pixel value histogram.

Fig. 8 is a graph showing pixel brightness values as a histogram (showing maximum brightness peaks) after the finger image extraction process for images 1-3 in Fig. 6. The graph on the left in Fig. 8 is a brightness histogram for the finger image extracted from image 1. The graph in the center in Fig. 8 is a brightness histogram for the finger image extracted from image 2. The graph on the right in Fig. 8 is a brightness histogram for the finger image extracted from image 3.
As in FIG. 7, in each graph in FIG. 8, "X" on the horizontal axis represents the class (brightness value) in the histogram, and "Y" on the vertical axis represents the frequency (number of pixels) in the histogram.
As shown in FIG. 8, the frequency of maximum luminance peaks in a finger image can also be used as an index for determining the gradation of blood flow density.

As mentioned above, glucose has the property of absorbing light at around 1600 nm. In the brightness histograms shown in Figures 7 and 8, the phenomenon in which a maximum peak appears on the low brightness side is due to the above property, causing the blood flow area in the image to appear black.

Fig. 9 is an explanatory diagram showing a configuration of a vital information measuring device 100 according to embodiment 2. As can be seen by comparing Fig. 2 according to embodiment 1 with Fig. 9 according to embodiment 2, the vital information measuring device 100 according to embodiment 2 includes a second-light-source photodiode 126B instead of the second-light-source area sensor 126.
In this manner, the vital information measuring device 100 according to the present disclosed technique may include the second light source photodiode 126B instead of the second light source area sensor 126.

As described above, conventional optical blood glucose level measuring devices do not have the third step described in the first embodiment, so the value measured by the sensor is affected by biological tissues other than blood vessels. More specifically, in conventional devices, even if a user's finger is irradiated with light of about 1600 [nm] and an image is taken, the light also includes light that passes through biological tissues other than blood vessels, so that an image with the desired contrast cannot be obtained. This influence by biological tissues other than blood vessels is the reason why the measurement accuracy cannot be improved.
In the vital information measuring device 100 according to the second embodiment, the data obtained in the second step does not include PD output information, i.e., blood vessel position information, and the processing circuit 150 does not perform processing to extract a portion corresponding to the position of the blood vessel. However, the vital information measuring device 100 according to the second embodiment improves the accuracy of blood glucose level calculation by referring not only to the PD data obtained from long wavelength IR, but also to brightness information (also referred to as "shade information") of the blood flow image from near infrared IR for personal authentication.
In the first embodiment, ST3 represents a step of extracting a portion corresponding to the position of a blood vessel in the image obtained by the second-light-source area sensor 126. In contrast, in the second embodiment, ST3 can be said to be replaced with a step of referring to the shading information of the blood flow obtained by the second-light-source photodiode 126B and reflecting it in the blood glucose level calculation.

ここで、数式（２）に登場するＹ_Ｐｅａｋは、極大値ピークの集合を表す。
なお、経験的に極大値ピークをとる輝度（Ｘ）がわかっている場合、数式（２）の条件式を用いずとも、その経験的に極大値ピークをとる輝度（Ｘ）（図８においては「所定輝度」と記載）における度数（画素数）を参照し、光量が適切であるか否かを判断する上での指標としてもよい。 Fig. 10 is a diagram illustrating an example of a luminance histogram of an image. In the graph shown in Fig. 10, "X" on the horizontal axis represents the class (luminance value) in the histogram, and "Y" on the vertical axis represents the frequency (number of pixels) in the histogram.
10, the "X" representing the class is assigned a number from 0 to 255. This indicates that each pixel in the image has an 8-bit (256 grayscale) value.
The maximum peaks shown in FIG. 8 can be extracted as those that satisfy the following conditions, where X is an integer between 0 and 255.

Here, Y _Peak appearing in the formula (2) represents a set of maximum peak values.
In addition, when the luminance (X) at which the maximum peak value is reached is known empirically, the frequency (number of pixels) at the luminance (X) at which the maximum peak value is reached empirically (represented as “predetermined luminance” in FIG. 8 ) may be referred to as an index for determining whether the amount of light is appropriate, without using the conditional expression of formula (2).

When the light amount and other conditions are different in this way, the brightness of the pixels in the image obtained by the first optical system changes. On the other hand, as described above, since glucose has the property of absorbing light at around 1600 [nm], the brightness also changes depending on the blood glucose level of the subject.
In response to this problem, the vital information measuring device according to the disclosed technology has a first optical system specialized for measuring the shape of blood vessels on the inserted user's finger, and a second optical system specialized for measuring vital information, such as HbA1c (hemoglobin A1c) in the blood, which are provided independently and function in conjunction with each other. Therefore, the vital information measuring device according to the disclosed technology can distinguish between factors based on conditions such as light quantity and factors based on the amount of blood glucose, and can be used in practice after performing appropriate calibration. Note that in the vital information measuring device according to the disclosed technology, calibration may be performed using a dummy finger (finger model) designed for calibration, rather than using the actual subject's finger.

A technical feature of the vital information measuring device according to embodiment 2 is that the processing circuit 150 distinguishes between factors based on conditions such as the amount of light and factors based on the amount of blood glucose, and performs appropriate calibration.
The vital information measuring device according to the second embodiment also achieves the excellent effects described in the first embodiment.

Embodiment 3.
The vital information measuring device, vital information measuring method, biological management system, and biological management method according to the third embodiment are modified examples of the vital information measuring device, vital information measuring method, biological management system, and biological management method according to the present disclosure. In the third embodiment, unless otherwise specified, the same symbols as those used in the previous embodiments are used. In the third embodiment, descriptions that overlap with those in the previous embodiments are omitted as appropriate.

Now, the vital information measuring device according to the disclosed technology may have a display screen such as a display on the device itself, or may be capable of transmitting the display information to an external device such as a personal computer or mobile terminal via a wired or wireless connection.

FIG. 11 is an image diagram showing the display content of a vital information measuring device according to embodiment 3.
The vital information measuring device according to the disclosed technology continuously measures vital information without the user being aware of it during a casual daily action such as unlocking the front door of the house. Therefore, a user will use the vital information measuring device according to the disclosed technology to measure vital information at most two to ten times a day, and it is not expected that a continuous time graph of blood glucose levels such as that shown in Fig. 11 will be obtained (Fig. 11 is merely an image).

FIG. 11 suggests that it is possible to divide blood glucose levels into five regions based on the user's average blood glucose level, and display to the user or medical professional information such as normal range, hyperglycemia, hyperglycemia, hypoglycemia, and hypoglycemia depending on the measured blood glucose level.
Regarding how to classify blood glucose levels, reference may be made to those published by academic societies, those based on international standards, etc.

The technical features of the vital information measuring device of embodiment 3 are that the device itself has a display screen such as a display, or is capable of transmitting the display information to an external device such as a personal computer or a mobile terminal via a wired or wireless connection.
The vital information measuring device according to the third embodiment also achieves the excellent effects described in the first embodiment.

The disclosed technology can be applied to a biometric management system and a biometric management method that provides feedback on a user's health condition to a user and a medical institution in a casual manner during daily life, thus realizing so-called daily medical checkups, and has industrial applicability. Furthermore, the disclosed technology is a technology that can become the standard with the spread of Web 3.0, which has been made possible by blockchain technology, that is, the next-generation Internet with decentralized power, and has great industrial applicability.

100 Vital information measuring device, 102 Inner holder, 104 Finger detection unit, 110 First light source, 112 Filter for first light source, 114 Collecting lens for first light source, 116 Area sensor for first light source, 120 Second light source, 122 Filter for second light source, 124 Collecting lens for second light source, 126 Area sensor for second light source, 130 Beam splitter, 150 Processing circuit, 200 Medical institution side data management device, 1000 Biometric management system.

Claims (5)

1. A vital information measuring method for a vital information measuring device including a first optical system having a wavelength range of 800 nm to 950 nm and a second optical system having a wavelength range including 1600 nm,
a first step of detecting an image including a blood vessel shape by the first optical system;
a second step of aligning the image obtained by the first optical system with the image obtained by the second optical system;
a third step of extracting a portion corresponding to a position of a blood vessel from the image obtained by the second optical system;
A fourth step of calculating HbA1c based on the image information extracted in the third step.
How to measure vital signs. the image obtained by the second optical system does not include position information of a blood vessel,
instead of the alignment in the second step and the third step, after the first step and before the fourth step, a processing step is performed in which a luminance value of an image obtained by the second optical system is calibrated based on a luminance histogram of the image obtained by the first optical system;
In the fourth step, HbA1c is calculated based on the calibrated luminance value instead of based on the image information extracted in the third step.
The vital information measuring method according to claim 1 . an inner holder that is a part inside the housing and keeps the user's fingers in the same position and posture during use;
a finger detection unit that detects the user's finger inserted into the inner holder;
A first light source that emits infrared light having a wavelength range of 800 nm to 950 nm;
a first light source filter that selectively passes only infrared light that is emitted from the first light source and has passed through a finger that is a measurement target;
a first light source condensing lens that condenses the infrared light that has passed through the first light source filter;
a first light source area sensor for detecting an image of blood vessels running throughout the finger;
A second light source that emits infrared light in a wavelength range from 1500 [nm] to 1700 [nm];
a second light source filter that selectively passes only infrared light that is emitted from the second light source and has passed through the finger that is the measurement target;
a second light source condensing lens that condenses the infrared light that has passed through the second light source filter;
a second light source area sensor for detecting an image for measuring HbA1c in blood;
and a processing circuit for performing control ,
the first light source, the first light source filter, the first light source condenser lens, and the first light source area sensor form a first optical system;
the second light source, the second light source filter, the second light source condenser lens, and the second light source area sensor form a second optical system;
The processing circuitry includes:
a first step of detecting an image including a blood vessel shape by the first optical system;
a second step of aligning the image obtained by the first optical system with the image obtained by the second optical system;
a third step of extracting a portion corresponding to a position of a blood vessel from the image obtained by the second optical system;
A fourth step of calculating HbA1c based on the image information extracted in the third step is performed.
Vital information measuring device. A biological information management system including the vital information measuring device according to claim 3 and a medical institution side data management device installed in a medical institution,
The data transmitted from the vital information measuring device and received by the medical institution's data management device has a data structure in which biometric authentication information and vital information are integrated.
Biometric control system. A biological information measuring method for a biological information measuring system including the vital information measuring device according to claim 3 and a medical institution side data management device installed in a medical institution, comprising:
the vital information measuring device encrypts biometric authentication information among the data of one person with a common encryption key, and encrypts the vital information with an individual encryption key assigned to each user;
The medical institution data management device decrypts the biometric authentication information using the common encryption key, compares it with pre-registered blood vessel shape data, identifies whose information it is, and decrypts the vital information using the individual encryption key.
Biometric control methods.

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