Biometric information detection device

Abstract

To provide a biological information detection device capable of detecting blood pressure of an object person while suppressing a hindrance to an action of the object person.SOLUTION: A biological information detection device 1 includes a reception antenna 13 for receiving a radio wave radiated from a transmission antenna 12 and transmitted through an object person, and an input unit 21 for acquiring a reception signal according to the radio wave received by the reception antenna 13 when the radio wave is radiated from the transmission antenna 12. The biological information detection device 1 includes a pulse wave sensor 15 for detecting a time waveform of the pulse wave of the object person, and a processing unit 24 for calculating blood pressure of the object person as biological information. The processing unit 24 calculates the blood pressure by calculating a physical amount correlated with the blood pressure from a time waveform of a signal component generated resulting from the movement of the heart of the object person from the reception signal, and correcting the physical amount on the basis of the time waveform of the pulse wave.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a biological information detection device that detects biological information of a subject. [Background technology]

[0002] Conventionally, a known method is to constantly detect pulse waves using a photoelectric pulse wave sensor attached to the subject's finger, while constantly observing the timing of R-wave appearance in an electrocardiogram test, and measure the pulse wave propagation time, which is correlated with the heart rate, based on these results (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-66681 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the device described in Patent Document 1 needs to detect a physical quantity correlated with a heartbeat while the subject is wearing electrodes for observing R waves of an electrocardiogram and a pulse wave sensor for detecting pulse waves. In this case, when detecting the subject's blood pressure, the subject's body is restrained at two or more points, which significantly impedes the subject's movements.

[0005] An object of the present disclosure is to provide a biological information detection device capable of detecting the blood pressure of a subject while minimizing the hindrance to the subject's movements. [Means for solving the problem]

[0006] The invention described in claim 1 is A biological information detection device for detecting biological information of a subject, a receiving antenna (13) that receives radio waves radiated from the transmitting antenna (12) and transmitted through the target person; a signal acquiring unit (21) that acquires a received signal corresponding to the radio wave received by the receiving antenna when the radio wave is radiated from the transmitting antenna; A pulse wave detection device (15, 16, 24, 25, 30) for detecting a time waveform of a pulse wave of a subject; A calculation unit (24) that calculates the blood pressure of the subject as biological information, The calculation unit calculates a physical quantity correlated with blood pressure from the time waveform of a signal component generated from the received signal due to the movement of the subject's heart, and calculates blood pressure by correcting the physical quantity based on the time waveform of the pulse wave.

[0007] According to this, since at least the physical quantity correlated with blood pressure is calculated based on the radio waves that have passed through the subject, it is possible to prevent the subject's body from being restrained during blood pressure detection, and therefore it is possible to measure the subject's blood pressure while preventing the subject's movements from being hindered.

[0008] Note that the reference symbols in parentheses attached to each component indicate an example of the correspondence between the component and specific components described in the embodiments described below. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic configuration diagram of a biological information detection device according to a first embodiment. [Diagram 2] FIG. 2 is a schematic diagram showing an example of an arrangement of transmitting antennas and receiving antennas. [Diagram 3] FIG. 2 is an explanatory diagram for explaining electrocardiogram data. [Figure 4] 2 is an explanatory diagram for explaining a time waveform of a received signal corresponding to a radio wave received by a receiving antenna. FIG. [Diagram 5] 5 is a flowchart showing a flow of processing executed by an information control unit of the biological information detecting device according to the first embodiment. [Figure 6] 4 is an explanatory diagram for explaining the relationship between the time waveform of a received signal and the time waveform of a pulse wave which is a sensor output of a pulse wave sensor. FIG. [Figure 7]10 is an explanatory diagram for explaining the correlation between the amount of fluctuation of a component extracted from a received signal and the amount of ventricular contraction. FIG. [Figure 8] FIG. 11 is a schematic configuration diagram of a biological information detection device according to a second embodiment. [Figure 9] FIG. 11 is a schematic configuration diagram of a biological information detection device according to a third embodiment. [Figure 10] FIG. 1 is an explanatory diagram for explaining some of the blood vessels in the body. [Figure 11] 10 is an explanatory diagram for explaining frequency characteristics of a sub-reception signal corresponding to a radio wave received by a sub-antenna; FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the embodiments of the present disclosure will be described with reference to the drawings. In the following embodiments, the same reference numerals are used for parts that are the same as or equivalent to those described in the preceding embodiments, and the description thereof may be omitted. In addition, in the embodiments, when only a part of the components is described, the components described in the preceding embodiments can be applied to the other parts of the components. In the following embodiments, each embodiment can be partially combined with each other, even if not specifically stated, as long as it does not cause any trouble in combination.

[0011] (First embodiment) The present embodiment will be described with reference to Fig. 1 to Fig. 7. In the present embodiment, an example will be described in which the blood pressure of one occupant P seated in a seat S of a vehicle is calculated as biological information using the biological information detection device 1 of the present disclosure.

[0012] In recent years, instead of treating illness after symptoms appear, preventive medicine that prevents illness through daily health management is gaining importance. Blood pressure is an index used in daily health management. Blood pressure is one of the indexes that measure the degree of strain on the heart H, and in Japan, it is a required item in health checkups. However, blood pressure varies depending on the time of measurement, meals eaten before the measurement, tension, etc., so it is recommended to measure blood pressure not only once a year at a health checkup, but also once a day at the same time and observe the progress. One environment that is considered to be suitable for this is commuting time by car. However, one of the conditions when riding in a car is "not to be disturbed while driving," so it is required to detect blood pressure without restraint.

[0013] Taking these factors into consideration, the biological information detection device 1 is configured to include a radio wave transmission type device that detects a physical quantity correlated with the blood pressure of the occupant P based on a radio wave signal that has passed through the occupant P. The biological information detection device 1 calculates the blood pressure of an occupant P seated in a driver's seat DS among the vehicle seats S as a subject. The biological information detection device 1 includes a transmitter 11, a transmitting antenna 12, a receiving antenna 13, a receiver 14, a pulse wave sensor 15, and an information control unit 20.

[0014] The transmitter 11 outputs a transmission signal of a predetermined frequency (for example, a frequency in the 900 MHz band) to the transmission antenna 12. The transmission antenna 12 is disposed on the instrument panel inside the vehicle, on the forward side in the traveling direction of the vehicle with respect to the driver's seat DS. The transmission antenna 12 transmits a radio signal corresponding to the transmission signal from the transmitter 11 toward the upper body of an occupant P seated in the driver's seat DS.

[0015] As shown in Fig. 2, the receiving antenna 13 is disposed opposite the transmitting antenna 12 across an occupant P seated in the driver's seat DS. In this embodiment, the receiving antenna 13 is attached to the seat back of the driver's seat DS. The receiving antenna 13 is configured to be able to receive radio waves transmitted from the transmitting antenna 12. The receiving antenna 13 receives radio waves radiated from the transmitting antenna 12 and transmitted through the occupant P who is the target.

[0016] The receiver 14 amplifies and outputs the radio signal received by the receiving antenna 13. Specifically, the receiver 14 amplifies the radio signal received by the receiving antenna 13 and outputs the amplified signal to the information control unit 20 as a biological signal P1.

[0017] The pulse wave sensor 15 is configured as a wearable sensor that is worn on the body of the occupant P to sequentially detect the pulse wave of the occupant P. The pulse wave sensor 15 detects the pulse wave at the part of the body of the occupant P where the sensor unit is worn. For example, a photoelectric pulse wave sensor, an impedance pulse wave sensor, or the like can be used as the pulse wave sensor 15. The pulse wave sensor 15 detects, as a waveform, a change in the volume of blood vessels that occurs as the heart H pumps blood. In this embodiment, the pulse wave sensor 15 constitutes a pulse wave detection device for detecting the time waveform of the pulse wave of the subject occupant P.

[0018] The information control unit 20 calculates the blood pressure of the occupant P as bioinformation based on the biosignal P1 acquired from the receiver 14 and the time waveform of the pulse wave detected by the pulse wave sensor 15. The information control unit 20 includes an input unit 21, a storage unit 22, an output unit 23, and a processing unit 24.

[0019] The input unit 21 is a signal acquisition unit that acquires a reception signal corresponding to radio waves received by the receiving antenna 13 when the radio waves are radiated from the transmitting antenna 12. The input unit 21 outputs the biosignal P1, which is an analog signal input from the receiver 14, to the processing unit 24 as a digital signal.

[0020] The storage unit 22 includes a RAM, a ROM, a writable nonvolatile memory, etc. The RAM, the ROM, and the writable nonvolatile memory constituting the storage unit 22 are all non-transient substantial storage media.

[0021] The output unit 23 outputs the signal input from the processing unit 24 to a device external to the information control unit 20. The external device to which the signal is output may be, for example, an in-vehicle navigation device that provides route guidance or the like, an in-vehicle data communication module that communicates with the outside of the vehicle, or a mobile communication terminal carried by the occupant P.

[0022] The processing unit 24 is a device that executes processing according to a program recorded in the ROM of the storage unit 22 or a writable non-volatile storage medium. The processing unit 24 in this embodiment uses the RAM of the storage unit 22 as a working area. The processing unit 24 functions as a calculation unit that calculates the blood pressure of the occupant P as biological information.

[0023] Here, the information control unit 20 is connected to an in-vehicle network via CAN communication. CAN is an abbreviation for Controller Area Network. The information control unit 20 is connected to a CAN bus 30, which is a communication bus. In-vehicle devices including a pulse wave sensor 15 are connected to this CAN bus 30. The information control unit 20 is capable of acquiring the time waveform of the pulse wave detected by the pulse wave sensor 15 via the CAN bus 30. Note that the information control unit 20 and the pulse wave sensor 15 may be connected by another connection means without via the CAN bus 30, or may be directly connected.

[0024] Next, the operation of the biological information detection device 1 will be described. The transmitter 11 outputs a transmission signal of a predetermined frequency to the transmission antenna 12. The transmission antenna 12 transmits radio waves corresponding to the transmission signal from the transmitter 11 toward the occupant P seated in the driver's seat DS. A part of the radio waves transmitted from the transmission antenna 12 passes through the occupant P seated in the driver's seat DS and is received by the receiving antenna 13.

[0025] The body of the occupant P functions as a dielectric with respect to the radio waves. Therefore, when the radio waves pass through the body of the occupant P, a dielectric loss occurs in the electric field strength of the radio waves. Among the parts of the body of the occupant P, the heart H changes its shape as it expands and contracts. Therefore, in the radio waves that pass through the heart H and reach the receiving antenna 13, a dielectric loss occurs in the electric field strength and changes according to the movement of the heart H.

[0026] In this way, the strength of the signal received by the receiving antenna 13 contains a component that changes periodically according to the movement of the heart H. Therefore, the level of the electrical signal output from the receiving antenna 13 to the receiver 14 when the receiving antenna 13 receives the radio waves from the transmitting antenna 12 contains a component that changes according to the movement of the heart H.

[0027] Here, FIG. 3 shows electrocardiogram data, with the horizontal axis indicating time and the vertical axis indicating the amplitude of the electrocardiogram waveform. The electrocardiogram data is a record of the electrical energy generated when the heart H contracts. The electrocardiogram data reflects the movement of the heart H. That is, the electrocardiogram data includes components that vary according to the movement of the heart H. Specifically, as shown in FIG. 3, the contraction of the atrium of the heart H corresponds to the P wave of the electrocardiogram. The contraction of the ventricle of the heart H corresponds to the QRS wave following the P wave. The voltage of the QRS wave is greater than the voltage of the P wave.

[0028] In the heart H, the atria and ventricles repeatedly contract, pushing blood that has entered from the atria into the ventricles, and then from the ventricles to the outside of the heart H. Specifically, blood is pumped from the right ventricle to the lungs and from the left ventricle to the entire body. For this reason, the amount of contraction of the left ventricle is proportional to the amount of blood ejected from the heart H to the entire body. Blood pressure changes according to the amount of blood ejected from the heart H to the entire body and vascular resistance. For this reason, there is a certain correlation between blood pressure and the movement of the heart H.

[0029] The strength of the signal received by the receiving antenna 13 of the biological information detection device 1 changes according to the movement of the heart H, similar to electrocardiogram data. The movement of the heart H has two stages, that of the atrium and the ventricle. Correspondingly, the signal strength of the time waveform of the received signal fluctuates in two stages, as shown in FIG. 4. According to research and studies by the inventors, it has been found that the change in the signal strength of the received signal becomes large when the ventricle contracts. Specifically, the amount of contraction of the ventricle of the heart H is strongly correlated with the maximum change ΔA in the signal strength of the received signal.

[0030] Taking these factors into consideration, the biological information detection device 1 of this embodiment extracts a characteristic amount of change in the signal strength of the received signal over a specified period of time as the amount of ventricular contraction of the heart H, and calculates the subject's blood pressure based on this component.

[0031] Here, blood pressure is affected by the blood flow rate and resistance, similar to the voltage V, current I, and resistance in Ohm's law. The blood flow rate is the amount of blood ejected from the ventricles of the heart H to the entire body. As mentioned above, the amount of blood ejected is strongly correlated with the amount of contraction of the ventricles of the heart H, and can be grasped by extracting the amount of contraction of the ventricles of the heart H from changes in the signal strength of the received signal.

[0032] On the other hand, resistance is vascular resistance, which indicates the difficulty of blood flowing through blood vessels. This vascular resistance differs from person to person, so it is necessary to grasp it for each individual in order to detect blood pressure with high accuracy. Vascular resistance can be obtained by calibration using a dedicated kit that simultaneously obtains the blood ejection volume and blood pressure.

[0033] However, when a user wants to perform calibration using a dedicated kit, the user needs to prepare the dedicated kit and operate the kit, which makes it practically difficult for the user to perform the above calibration, and the user has no choice but to request a professional such as a dealer to handle the calibration.

[0034] Taking these factors into consideration, the biological information detection device 1 of this embodiment is configured to utilize the strong correlation between vascular resistance and pulse wave delay to grasp vascular resistance from pulse wave delay. This grasping of vascular resistance is realized by calculation processing in the processing unit 24 of the information control unit 20. Hereinafter, the flow of processing executed by the processing unit 24 of the information control unit 20 will be described with reference to Fig. 5. The processing shown in Fig. 5 is executed by the information control unit 20 periodically or irregularly when an occupant P is seated in the driver's seat DS of the vehicle.

[0035] 5, in step S100, the processing unit 24 acquires, via the receiver 14, a time waveform of a signal received by the receiving antenna 13 when a radio wave is transmitted from the transmitting antenna 12. In addition, the processing unit 24 sequentially acquires, from the pulse wave sensor 15, a time waveform of a pulse wave at the fingertip of the occupant P.

[0036] Here, the time waveform of the received signal is the change in signal strength over time, and is, for example, a waveform like that shown in the upper part of Fig. 4 and Fig. 6. The time waveform of the received signal contains a component that has a correlation with the movement of the ventricle of the heart H. Moreover, the time waveform of the pulse wave is a waveform like that shown in the lower part of Fig. 6. The pulse wave is generated when the heart H pumps blood. For this reason, the time waveform of the pulse wave has characteristics that correspond to the time waveform of the received signal.

[0037] Next, in step S110, the processing unit 24 determines whether or not the delay time ΔT of the pulse wave of the occupant P seated in the driver's seat DS is stored in the memory unit 22. This determination process is performed based on the information stored in the memory unit 22.

[0038] If the delay time ΔT is not stored in the storage unit 22, the processing unit 24 proceeds to step S120. On the other hand, if the delay time ΔT is stored in the storage unit 22, the processing unit 24 skips steps S120 and S130 and proceeds to step S140.

[0039] In step S120, the processing unit 24 detects, as a delay time ΔT, the time from when a first feature A appears in the time waveform of the signal component of the received signal to when a second feature B corresponding to the first feature A appears in the time waveform of the pulse wave.

[0040] For example, the processing unit 24 identifies a point where the amplitude is maximum in the time waveform of the signal component of the received signal as the first feature amount A. The processing unit 24 also identifies a point in the time waveform of the pulse wave that corresponds to the first feature amount A as the second feature amount B. For example, the processing unit 24 identifies a point where the amplitude is first maximum in the time waveform of the pulse wave after the timing at which the first feature amount A appears as the second feature amount B.

[0041] Then, the processing unit 24 detects the time from the appearance of the first feature amount A to the appearance of the second feature amount B as a delay time ΔT. For example, the processing unit 24 detects the time difference between the time ta when the first feature amount A appears and the time tb when the second feature amount B appears as the delay time ΔT.

[0042] Next, in step S130, the processing unit 24 stores the delay time ΔT in the storage unit 22. Specifically, the processing unit 24 stores the delay time ΔT in the non-volatile memory of the storage unit 22 so that the delay time ΔT is held in the storage unit 22 even when the ignition switch of the vehicle is turned off.

[0043] Here, the pulse wave delay time ΔT is a parameter that differs between individuals. For this reason, the processing unit 24 stores the delay time ΔT in the storage unit 22 in association with specific information that identifies the occupant P. Examples of the specific information include unique information of the occupant P, such as a facial image, fingerprint information, etc.

[0044] Next, in step S140, the processing unit 24 extracts signal components caused by ventricular contraction from the received signal. As described above, the amount of contraction of the ventricle of the heart H is strongly correlated with the maximum change amount ΔA of the signal strength of the received signal. For this reason, the processing unit 24 extracts the maximum change amount ΔA of the changes in the signal strength of the received signal over a predetermined period as a characteristic change amount.

[0045] Next, in step S150, the processing unit 24 calculates the contraction amount of the ventricle as a physical quantity correlated with the blood pressure. For example, the processing unit 24 calculates the contraction amount of the ventricle using the maximum change amount ΔA extracted in step S120, with reference to a control map or a relational expression that defines the relationship between the maximum change amount ΔA and the contraction amount of the ventricle shown in Fig. 7. The control map or the relational expression that defines the relationship between the maximum change amount ΔA and the contraction amount of the ventricle can be created, for example, by synchronously acquiring an echo image that allows the contraction amount of the ventricle to be grasped and a received signal of the receiving antenna 13.

[0046] Next, in step S160, the processing unit 24 calculates the blood pressure of the occupant P by correcting the amount of contraction of the ventricle by the delay time ΔT. An example of a method for calculating the blood pressure will be described below.

[0047] Blood pressure can be expressed by the following formula F1, which is based on Ohm's law, which shows the relationship between voltage V, current I, and electrical resistance R in an electrical circuit.

[0048] Blood pressure = vascular resistance × cardiac output (F1) The vascular resistance in formula F1 can be expressed by the following formula F2.

[0049] Vascular resistance = α × pulse wave delay time ΔT (F2) Here, α in the formula F2 is a constant that is set in advance to convert the delay time ΔT into vascular resistance.

[0050] Moreover, the cardiac output in formula F1 can be expressed by the following formula F3.

[0051] Cardiac output = β × ventricular contraction volume (F3) In the formula F3, β is a constant that is set in advance to convert the amount of contraction of the ventricle into cardiac output.

[0052] The above formula F1 can be transformed into the following formula F4 using formulas F2 and F3.

[0053] Blood pressure = (α × pulse wave delay time ΔT) × (β × ventricular contraction amount) = γ × pulse wave delay time ΔT × ventricular contraction amount (F4) In the formula F4, γ is a constant that is set in advance as a parameter specific to the biological information detection device 1.

[0054] The processing unit 24 of this embodiment calculates the blood pressure by substituting the delay time ΔT stored in the storage unit 22 and the ventricular contraction amount calculated in step S150 into the above formula F4. That is, the processing unit 24 calculates the blood pressure based on the multiplication result of the ventricular contraction amount, which is a physical quantity correlated with the blood pressure, and the delay time ΔT.

[0055] Specifically, the processing unit 24 refers to the identification information for identifying the occupant P and reads out the delay time ΔT corresponding to the occupant P from the storage unit 22. The processing unit 24 identifies the occupant P by, for example, comparing a face image, fingerprint information, etc. of the occupant P acquired from an in-vehicle device with the identification information of the occupant P stored in the storage unit 22, and then reads out the delay time ΔT corresponding to the occupant P from the storage unit 22. Then, the processing unit 24 corrects the physical quantity correlated with blood pressure based on the delay time ΔT read out from the storage unit 22.

[0056] Next, in step S160, the processing unit 24 outputs the blood pressure calculated in step S150 from the output unit 23 to a device external to the biological information detecting device 1. The processing unit 24 may be configured to output the blood pressure to, for example, a driver status monitor DSM that detects the wakefulness or the like of the occupant P.

[0057] The above-described biological information detection device 1 includes a receiving antenna 13 that receives radio waves radiated from the transmitting antenna 12 and transmitted through the occupant P, and an input unit 21 that acquires a reception signal corresponding to the radio waves received by the receiving antenna 13 when the radio waves are radiated from the transmitting antenna 12. The biological information detection device 1 includes a pulse wave sensor 15 for detecting the time waveform of the pulse wave of the occupant P, and a processing unit 24 that calculates the blood pressure of the occupant P as biological information. The processing unit 24 calculates a physical amount correlated with the blood pressure from the time waveform of a signal component generated due to the movement of the heart H of the occupant P from the received signal, and calculates the blood pressure by correcting the physical amount based on the time waveform of the pulse wave. According to this, the physical amount correlated with the blood pressure is calculated based on the radio waves transmitted through the subject, so that restraint of the body of the occupant P during blood pressure detection can be suppressed. Therefore, the blood pressure of the occupant P can be measured while suppressing interference with the occupant P's actions.

[0058] (1) The processing unit 24 detects the time from when a first feature A appears in the time waveform of the signal component of the received signal until when a second feature B corresponding to the first feature A appears in the time waveform of the pulse wave as the delay time ΔT. The processing unit 24 calculates blood pressure by correcting the amount of ventricular contraction, which is a physical quantity correlated with blood pressure, based on the delay time ΔT. According to this, if the physical quantity correlated with blood pressure is corrected by the delay time ΔT correlated with vascular resistance, the difference in vascular resistance between individuals can be reflected in the blood pressure, so that the blood pressure of the occupant P can be measured with high accuracy. In addition, since the delay time ΔT can be detected in the shortest time of one beat, the calibration work time for calculating the blood pressure can be shortened.

[0059] (2) Specifically, the processing unit 24 calculates the blood pressure based on the result of multiplying a physical quantity correlated with the blood pressure by the delay time ΔT. This allows the difference in vascular resistance between individuals to be reflected in the blood pressure through simple calculations.

[0060] (3) The processing unit 24 associates specific information for identifying the occupant P with the delay time ΔT and stores the information in the memory unit 22. When calculating the blood pressure of the occupant P, the processing unit 24 reads the delay time ΔT corresponding to the occupant P from the memory unit 22 by referring to the specific information for identifying the occupant P, and corrects the physical quantity correlated with the blood pressure based on the delay time ΔT read from the memory unit 22. This makes it possible to correct the physical quantity correlated with the blood pressure using the delay time ΔT obtained in advance, thereby preventing detection of the delay time ΔT from becoming a factor in restraining the body of the occupant P at the time of blood pressure detection.

[0061] (Modification of the first embodiment) In the first embodiment, the detection of the delay time ΔT and the calculation of the blood pressure are performed in a series of processes, but the detection of the delay time ΔT and the calculation of the blood pressure may be performed at different times. For example, the detection of the delay time ΔT may be performed while the vehicle is parked and stopped, and the calculation of the blood pressure may be performed while the vehicle is running. In this way, it is not necessary to wear the pulse wave sensor 15 while the vehicle is running, so that the restraint of the body of the occupant P while the vehicle is running can be suppressed.

[0062] The determination process of step S110 described in the first embodiment may be, for example, to determine whether or not the elapsed time since the delay time ΔT was stored in the storage unit 22 is within a predetermined time. In this determination process, if the determination result is negative, the process proceeds to step S120, and if the determination result is positive, the process skips steps S120 and S130 and proceeds to step S140. In this way, the delay time ΔT is updated at any time, so that it is possible to realize blood pressure measurement that reflects changes in vascular resistance accompanying changes in the body.

[0063] Second embodiment Next, a second embodiment will be described with reference to Fig. 8. In this embodiment, the device for detecting the time waveform of the pulse wave is different from that in the first embodiment. In this embodiment, the difference from the first embodiment will be mainly described.

[0064] The biological information detection device 1 is configured to detect the time waveform of the pulse wave without contacting the occupant P. That is, the biological information detection device 1 is configured as a pulse wave detection device using a non-contact sensor that sequentially detects the pulse wave of the occupant P in a non-contact manner without being attached to the body of the occupant P.

[0065] 8, the biological information detection device 1 has a camera 31 for capturing an image of the face of an occupant P in the vehicle cabin instead of the pulse wave sensor 15. This camera 31 may be, for example, a dedicated camera, or may be one used in the driver status monitor DSM.

[0066] In the facial image captured by the camera 31, the luminance of pixels in a specific region in which blood vessels are present on the face changes in response to the pulse rate. For this reason, the information control unit 20 periodically acquires an image of a range including the face of the occupant P captured by the camera 31, and detects the time waveform of the pulse wave based on the time change in the image. Specifically, the information control unit 20 detects the time waveform of the pulse wave by observing the change in luminance of pixels in a specific region in which blood vessels are present on the face of the occupant P in the facial image captured by the camera 31.

[0067] Here, the information control unit 20 of this embodiment includes an image processing unit 25 for extracting information corresponding to the time waveform of the pulse wave from an image captured by the camera 31. In this embodiment, the image processing unit 25 and the camera 31 constitute a pulse wave detection device for detecting the time waveform of the pulse wave of a subject.

[0068] The rest is the same as in the first embodiment. The biological information detection device 1 of this embodiment can obtain the same effects as in the first embodiment, which are achieved by a configuration common to the first embodiment or an equivalent configuration.

[0069] Moreover, according to this embodiment, the following effects can be obtained.

[0070] (1) The biological information detecting device 1 is configured to be capable of detecting the time waveform of the pulse wave without contacting the occupant P. This makes it possible to measure the blood pressure of the occupant P without restraining the body of the occupant P.

[0071] (2) Specifically, the biological information detection device 1 periodically acquires an image of an area including the face of the occupant P captured by the camera 31, and detects the time waveform of the pulse wave based on the time change of the image. This makes it possible to detect the time waveform of the pulse wave of the occupant P without restraining the body of the occupant P. In particular, when the camera 31 is also used for the driver status monitor DSM, there is no need to add a separate dedicated device, and therefore an increase in the number of parts of the biological information detection device 1 can be suppressed.

[0072] Third embodiment Next, a third embodiment will be described with reference to Fig. 9 to Fig. 11. In this embodiment, the device for detecting the time waveform of the pulse wave is different from the first and second embodiments. In this embodiment, the difference from the first embodiment will be mainly described.

[0073] 9, the biological information detecting device 1 has a sub-antenna 16 instead of the pulse wave sensor 15. The sub-antenna 16 is disposed opposite the transmitting antenna 12 across the occupant P seated in the driver's seat DS. The sub-antenna 16 is attached to the seat back of the driver's seat DS together with the receiving antenna 13. The sub-antenna 16 is disposed at a position different from the receiving antenna 13 and receives radio waves radiated from the transmitting antenna 12 and transmitted through the occupant P.

[0074] In the biological information detection device 1, the receiving antenna 13 is disposed so as to receive radio waves that have passed through the chest region of the body of the occupant P, including the heart H. In addition, in the biological information detection device 1, the sub-antenna 16 is disposed so as to receive radio waves that have passed through a region of the body of the occupant P other than the chest region. Specifically, the sub-antenna 16 is disposed in a lumbar support region of the driver's seat DS that supports the waist region of the occupant P, so as to receive radio waves that have passed through the abdominal aorta shown in FIG.

[0075] Here, the shape of blood vessels changes in response to the pulse. Therefore, in the radio waves that pass through blood vessels and their surroundings to reach sub-antenna 116, dielectric loss that occurs in the electric field strength changes in response to the movement of the blood vessels. Therefore, the strength of the sub-reception signal received by sub-antenna 16 contains a component that changes periodically in response to the movement of the abdominal aorta. In other words, the level of the electrical signal output from sub-antenna 16 to receiver 14 when sub-antenna 16 receives radio waves from transmitting antenna 12 contains a component that fluctuates in response to the movement of the abdominal aorta.

[0076] For this reason, the processing unit 24 of this embodiment detects the time waveform of the pulse wave based on the time waveform of the signal component of the sub-received signal. Specifically, the processing unit 24 detects the change in the signal strength of the sub-received signal over a predetermined period as the time waveform of the pulse wave in the abdominal aorta. In this embodiment, the sub-antenna 16 and the processing unit 24 constitute a pulse wave detection device for detecting the time waveform of the subject's pulse wave.

[0077] The rest is the same as in the first embodiment. The biological information detection device 1 of the present embodiment can obtain the effects achieved by the configuration common to the first and second embodiments or the equivalent configuration, similarly to the first and second embodiments.

[0078] Moreover, according to this embodiment, the following effects can be obtained.

[0079] (1) The biological information detecting device 1 is configured to be capable of detecting the time waveform of the pulse wave without contacting the occupant P. This makes it possible to measure the blood pressure of the occupant P without restraining the body of the occupant P.

[0080] (2) The biological information detection device 1 includes a sub-antenna 16 that is disposed at a position different from the receiving antenna 13 and receives radio waves radiated from the transmitting antenna 12 and transmitted through the occupant P. When radio waves are radiated from the transmitting antenna 12, the input unit 21 acquires a sub-received signal corresponding to the radio waves received by the sub-antenna 16. Then, the processing unit 24 detects the time waveform of the pulse wave based on the time waveform of the signal component of the sub-received signal. This also makes it possible to detect the time waveform of the pulse wave of the occupant P without restraining the body of the occupant P. In particular, the physical quantity correlated with blood pressure and the time waveform of the pulse wave can be detected by using radio waves from the common transmitter 11 and transmitting antenna 12. This greatly contributes to simplifying the biological information detection device 1.

[0081] (3) Specifically, the receiving antenna 13 is disposed so as to receive radio waves that have passed through the chest area of ​​the body of the occupant P, including the heart H. In addition, the sub-antenna 16 is disposed so as to receive radio waves that have passed through an area of ​​the body of the occupant P other than the chest area. In this way, blood pressure is calculated based on the radio waves that have passed through the subject without contacting the occupant P, so that restraint of the subject's body during blood pressure detection can be suppressed.

[0082] (4) Here, when the pulse wave detection device is configured with a non-contact type sensor as in the second and third embodiments, the time waveform of the pulse wave acquired as the sensor output is very small compared to the case where pulse wave sensor 15 is used. And, when the time waveform of the pulse wave is detected while the vehicle is running, it may be difficult to detect it separately from signal components caused by vibration of the vehicle.

[0083] For this reason, it is preferable to use the time waveform of the pulse wave when the pulse wave signal is stable while the vehicle is stopped, such as when waiting at a traffic light, or when the vehicle is running. The presence or absence of a stable portion of the pulse wave signal can be determined, for example, based on the peak intensity or SN ratio in the frequency characteristics of a certain fixed section as shown in FIG. 11. For example, if a single peak intensity is formed in the frequency characteristics of a certain section, it can be determined that the pulse wave signal has a stable portion. The frequency characteristics shown in FIG. 11 can be obtained by performing a Fourier transform on the time waveform of the received signal. The SN ratio is the value obtained by dividing the peak intensity by the average value of the intensities of the other frequencies.

[0084] (Modification of the third embodiment) In the third embodiment, an example has been described in which the sub-antenna 16 is disposed in the lumbar support portion of the driver's seat DS that supports the lower back of the occupant P so as to receive radio waves that have passed through the abdominal aorta, but the location of the sub-antenna 16 is not limited to this. The sub-antenna 16 may also be disposed in the headrest, for example, so as to receive radio waves that have passed through the carotid artery. The sub-antenna 16 may also be disposed in the seat cushion that forms the seat surface of the driver's seat DS so as to receive radio waves that have passed through the popliteal artery.

[0085] (Other embodiments) Representative embodiments of the present disclosure have been described above, but the present disclosure is not limited to the above-described embodiments and can be modified in various ways, for example, as described below.

[0086] In the above embodiment, the delay time ΔT is detected as the time from when the first feature A appears in the time waveform of the signal component of the received signal to when the second feature B appears in the time waveform of the pulse wave, but is not limited to this. The delay time ΔT may be detected, for example, by a control map or a relational expression that associates the time waveform of the signal component of the received signal, the time waveform of the pulse wave, and the delay time ΔT in advance.

[0087] In the above embodiment, the blood pressure is calculated based on the multiplication result of the physical quantity correlated with the blood pressure and the delay time ΔT, but the present invention is not limited to this. For example, the blood pressure may be calculated by a control map or a relational expression that associates the physical quantity correlated with the blood pressure, the delay time ΔT, and the blood pressure in advance.

[0088] In the above embodiment, when calculating the blood pressure of the occupant P, the processing unit 24 automatically reads out the delay time ΔT corresponding to the occupant P from the storage unit 22. However, the present invention is not limited to this. For example, the delay time ΔT selected by the occupant P as information related to his / her pulse wave may be read out from the storage unit 22.

[0089] In the above embodiment, an example has been described in which the delay time ΔT is detected while the vehicle is parked or stopped or while the vehicle is running. However, the delay time ΔT may also be detected by dedicated equipment, for example, by using the waiting time for vehicle inspection at a dealer or the like.

[0090] The pulse wave detection device is not limited to those described in the first to third embodiments, and may be configured to detect a pulse wave from a body surface displacement caused by a pulse, for example, by using a piezoelectric sensor, a millimeter wave radar, or the like as a displacement sensor. Note that since the pulse wave detection device is a device for determining the delay time ΔT, it is sufficient to bring the device into the vehicle when determining the delay time ΔT, and it is not necessary for the device to be permanently installed in the vehicle.

[0091] In the above embodiment, the receiving antenna 13 is attached to the sheet S as an example, but the present invention is not limited to this, and the receiving antenna 13 may be attached to something other than the sheet S.

[0092] In the above embodiment, the transmitting antenna 12 and the receiving antenna 13 are arranged side by side at the front and rear of the vehicle with the occupant P in between, but the biometric information detection device 1 is not limited to this. For example, the transmitting antenna 12 and the receiving antenna 13 may be arranged side by side on the left and right sides of the vehicle with the occupant P in between. The biometric information detection device 1 may be configured to calculate biometric information of not only the driver but also other occupants P. Furthermore, the biometric information detection device 1 may be used not only for calculating the biometric information of the vehicle occupant P, but also for calculating the biometric information of a person outside the vehicle (for example, inside a building).

[0093] In the above-described embodiments, it goes without saying that the elements constituting the embodiments are not necessarily essential, except in cases where it is particularly expressly stated that they are essential or where they are clearly considered to be essential in principle.

[0094] In the above-described embodiments, when numerical values ​​such as the number, values, amounts, ranges, etc. of components of the embodiments are mentioned, they are not limited to the specific numbers unless expressly stated as required or clearly limited to a specific number in principle.

[0095] In the above-described embodiments, when referring to the shapes, positional relationships, etc. of components, etc., there is no limitation to those shapes, positional relationships, etc., unless specifically stated or in principle limited to a specific shape, positional relationship, etc.

[0096] In the above-described embodiment, when the external environment information of the vehicle is acquired from a sensor, it is also possible to eliminate the sensor and receive the external environment information from a server or cloud outside the vehicle. Alternatively, it is also possible to eliminate the sensor and acquire related information related to the external environment information from a server or cloud outside the vehicle, and estimate the external environment information from the acquired related information.

[0097] The control unit and the method of the present disclosure may be implemented in a special-purpose computer provided by configuring a processor and a memory programmed to execute one or more functions embodied in a computer program. The control unit and the method of the present disclosure may be implemented in a special-purpose computer provided by configuring a processor with one or more dedicated hardware logic circuits. The control unit and the method of the present disclosure may be implemented in one or more special-purpose computers configured by a combination of a processor and a memory programmed to execute one or more functions and a processor configured with one or more hardware logic circuits. The computer program may also be stored in a computer-readable non-transitory tangible recording medium as instructions executed by a computer. [Explanation of symbols]

[0098] 1 Biometric information detection device 12 Transmitting Antenna 13 Receiving antenna 14 Receiver 15 Pulse wave sensor (pulse wave detection device) 21 Input section (signal acquisition section) 24 Processing section (calculation section)

Claims

1. A biological information detection device for detecting biological information of a subject, a receiving antenna (13) for receiving radio waves radiated from the transmitting antenna (12) and transmitted through the subject; a signal acquisition unit (21) that acquires a received signal corresponding to the radio waves received by the receiving antenna when the radio waves are radiated from the transmitting antenna; A pulse wave detection device (15, 16, 24, 25, 30) for detecting a time waveform of a pulse wave of the subject; A calculation unit (24) that calculates the blood pressure of the subject as the biological information, The calculation unit calculates a physical quantity correlated with the blood pressure from a time waveform of a signal component generated from the received signal due to the movement of the subject's heart, and calculates the blood pressure by correcting the physical quantity based on the time waveform of the pulse wave.

2. The calculation unit is a delay time of the pulse wave is detected as a time from when a first feature amount appears in the time waveform of the signal component until when a second feature amount corresponding to the first feature amount appears in the time waveform of the pulse wave; The biological information detection device according to claim 1 , wherein the blood pressure is calculated by correcting the physical amount based on the delay time.

3. The biological information detection device according to claim 2 , wherein the calculation unit calculates the blood pressure based on a result of multiplication of the physical amount and the delay time.

4. The calculation unit stores in a storage unit (22) specific information for identifying the subject and the delay time in association with each other, 4. The biological information detection device according to claim 2 or 3, wherein, when calculating the blood pressure of the subject, the delay time corresponding to the subject is read from the memory unit by referring to the specific information, and the physical quantity is corrected based on the delay time read from the memory unit.

5. The biological information detection device according to claim 1 , wherein the pulse wave detection device detects a time waveform of the pulse wave without contacting the subject.

6. The pulse wave detection device according to any one of claims 1 to 5, wherein the pulse wave detection device periodically acquires an image of an area including the subject's face captured by a camera (31), and detects a time waveform of the pulse wave based on a change in the image over time.

7. The pulse wave detection device includes a sub-antenna (16) that is disposed at a position different from the receiving antenna and receives radio waves radiated from the transmitting antenna and transmitted through the subject, the signal acquisition unit acquires, as a sub-received signal, a signal corresponding to the radio wave received by the sub-antenna when the radio wave is radiated from the transmitting antenna; 6. The biological information detection device according to claim 1, wherein the calculation section detects a time waveform of the pulse wave based on a time waveform of the sub-reception signal.

8. the receiving antenna is disposed so as to receive radio waves that have passed through a chest region including the heart of the subject; The biological information detection device according to claim 7 , wherein the sub-antenna is disposed so as to receive radio waves that have passed through a part of the subject's body other than the chest part.

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