JP2018117800A - Heart rate acquisition system and heart rate acquisition method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heart rate acquisition system for acquiring a heart rate accurately.SOLUTION: A heart rate acquisition system 100 for acquiring a heart rate of a user of a vehicle, includes a transmission part 101 located in the vehicle for transmitting an electromagnetic wave to the user, a plurality of reception parts 102A, 102B located in the vehicle for receiving the electromagnetic wave reflected by the user, and a processing part 110 for acquiring the heart rate of the user, using signals of a plurality of the electromagnetic waves received by the plurality of reception parts. The processing part 110 converts the signals of the plurality of electromagnetic waves to a plurality of conversion signals, using the phase of each signal, calculates a correlation value between the plurality of conversion signals, acquires the heart rate of the user, using the correlation value, and performs output according to the heart rate of the user.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a heartbeat acquisition system and a heartbeat acquisition method.

  Patent Document 1 discloses an apparatus for measuring a heart rate with a microwave transceiver disposed inside a backrest of a driver's seat of a vehicle.

Japanese Patent No. 5131744

  However, in the apparatus of Patent Document 1, the microwave transceiver receives a reflected wave by irradiating the subject with the microwave from the backrest of the driver's seat, and receives (receives) the reflected wave. Due to mixing of clutter and Doppler signals in the vehicle caused by acceleration / deceleration of the heartbeat, a heartbeat signal, which is a weak signal, may not be accurately detected from the reflected wave.

  The present disclosure shows a heartbeat acquisition system that can accurately acquire a heartbeat in a vehicle. Moreover, this indication shows the heartbeat acquisition method which can acquire a heartbeat accurately in a vehicle.

  A heartbeat acquisition system according to an aspect of the present disclosure is a heartbeat acquisition system that acquires a heartbeat of a user of a vehicle, the transmitter being located in the vehicle and transmitting electromagnetic waves to the user, and the vehicle A plurality of receiving units that are positioned and receive electromagnetic waves reflected by the user; and a processing unit that acquires a heartbeat of the user using signals of the plurality of electromagnetic waves received by the plurality of receiving units, The processing unit (a) converts the signals of the plurality of electromagnetic waves into a plurality of converted signals by using phases of the signals of the plurality of electromagnetic waves, and (b) calculates a correlation value between the plurality of converted signals. And (c) using the correlation value, obtains the heartbeat of the user, and (d) performs output according to the heartbeat of the user.

  A heartbeat acquisition method according to an aspect of the present disclosure is a heartbeat acquisition method for acquiring a heartbeat of a user of a vehicle, wherein (a) an electromagnetic wave is transmitted to the user in the vehicle, and (b) the user The reflected electromagnetic waves are received using a plurality of receiving devices, and (c) a plurality of converted signals using the phases of the signals of the plurality of electromagnetic waves received by the plurality of receiving devices. (D) calculating a correlation value between the plurality of converted signals, and (e) acquiring the heartbeat of the user using the correlation value.

  The heartbeat acquisition system and the heartbeat acquisition method of the present disclosure can acquire a heartbeat with high accuracy.

FIG. 1 is a block diagram showing a configuration of a heartbeat acquisition system according to the first embodiment. FIG. 2 is a diagram illustrating an example of a transmission unit and a plurality of reception units of the heartbeat acquisition system. FIG. 3 is a diagram for explaining the correction of the phase angle of the received signal in the heartbeat acquisition system. FIG. 4 is a diagram for explaining phase conversion in the phase conversion unit of the heartbeat acquisition system. FIG. 5 is a diagram for explaining the calculation of the correlation value in the correlation calculation unit of the heartbeat acquisition system. FIG. 6 is a diagram for explaining the setting of the time difference related to the distance between the plurality of receiving units in the time difference setting unit of the heartbeat acquisition system. FIG. 7 is a diagram for explaining heart rate estimation based on correlation of signals from a plurality of receiving units in the first embodiment. FIG. 8 is a diagram illustrating a display example by the presentation unit of the heartbeat acquisition system. FIG. 9 is a flowchart showing the operation of the heartbeat acquisition system. FIG. 10 is a diagram illustrating a data example of each instantaneous received signal related to a reflected wave from the human body received by the receiving unit. FIG. 11 is a diagram illustrating an example of data after rotation of the phase angle of the reception signal illustrated in FIG. 10. FIG. 12 is a graph for the I component of the received signal after the rotation of the phase angle shown in FIG. FIG. 13 is a diagram illustrating a data example of correlation values between signals from a plurality of receiving units of the heartbeat acquisition system. FIG. 14 is a graph for comparison between a heartbeat interval acquired by the heartbeat acquisition system according to Embodiment 1 and a heartbeat interval acquired by an electrocardiograph. FIG. 15 is a block diagram illustrating a configuration of the heartbeat acquisition system according to the second embodiment. FIG. 16 is a diagram for explaining calculation of feature points in a feature point calculation unit of the heartbeat acquisition system. FIG. 17 is a diagram illustrating an example of feature point data extracted from the I component of the phase-converted received signal in the second embodiment. FIG. 18 is a diagram for explaining heart rate estimation based on correlation in which time differences between signals from a plurality of reception units in Embodiment 2 are adjusted. FIG. 19 is a block diagram illustrating a configuration of the heartbeat acquisition system according to the third embodiment. FIG. 20 is a diagram for explaining template matching in the heartbeat acquisition system according to the third embodiment. FIG. 21 is a block diagram showing a configuration of a heartbeat acquisition system according to the fourth embodiment. FIG. 22 is a diagram illustrating an example of vehicle travel control by the heartbeat acquisition system according to the fourth embodiment. FIG. 23 is a block diagram showing a configuration of the heartbeat acquisition system according to the fifth embodiment. FIG. 24 is a diagram for explaining noise component cancellation processing based on signals from a plurality of reception units in the fifth embodiment.

  Recently, in order to prevent accidents caused by sudden changes in the physical condition of the driver when driving the vehicle, there is an increasing need for a technique for measuring the vital data of the driver during driving. As a technique for acquiring vital data without excessively restraining the driver during driving, the apparatus disclosed in Patent Document 1 is such that the microwave transceiver irradiates the subject with microwaves from the backrest of the driver's seat. The heartbeat is measured by receiving (receiving) the reflected wave. However, when the vehicle is traveling, the heartbeat signal, which is a weak signal, may not be accurately detected from the reflected wave due to mixing of clutter and Doppler signals in the vehicle caused by acceleration / deceleration in the longitudinal direction of the vehicle.

  Conventionally, the heartbeat signal is acquired based on the intensity of the signal without adjusting the phase of the signal obtained from the reflected wave, but the inventor of the present application adjusts the phase of the received signal obtained from the reflected wave. The present inventors have found that there are cases where the component of the human body movement caused by the heartbeat that appears in the received signal can be more emphasized (that is, it can be obtained with high accuracy).

  Therefore, in order to obtain a heartbeat signal with high accuracy, the present disclosure is weak by performing phase conversion on a reception signal obtained from a reflected wave of an electromagnetic wave irradiated to a vehicle user (for example, a driver). The heartbeat acquisition system and heartbeat acquisition method which emphasize the heartbeat signal which is a signal are shown. The phase conversion for the received signal is useful when the received signal exhibits a substantially uniform phase. As an arrangement of a receiving unit (for example, a receiver) that receives a reflected wave from a user, which is suitable for enhancement of a heartbeat signal by phase conversion, the present disclosure provides a receiving unit below a seating surface on which a user is seated in a vehicle Shows the technology to be placed.

  A heartbeat acquisition system according to an aspect of the present disclosure is a heartbeat acquisition system that acquires a heartbeat of a user of a vehicle, the transmitter being located in the vehicle and transmitting electromagnetic waves to the user, and the vehicle A plurality of receiving units that are positioned and receive electromagnetic waves reflected by the user; and a processing unit that acquires a heartbeat of the user using signals of the plurality of electromagnetic waves received by the plurality of receiving units, The processing unit (a) converts the signals of the plurality of electromagnetic waves into a plurality of converted signals by using phases of the signals of the plurality of electromagnetic waves, and (b) calculates a correlation value between the plurality of converted signals. And (c) using the correlation value, obtains the heartbeat of the user, and (d) performs output according to the heartbeat of the user. Here, the vehicle has a wheel and is a moving body on which a human (that is, a vehicle user) is placed, and includes, for example, an automobile, a train, a wheelchair, a robot having wheels, a machine having wheels, and the like. The transmission unit and the reception unit are objects that are located in the vehicle, that is, those that are used in the vicinity of the vehicle (for example, within a range of 1 m from the vehicle) regardless of the inside or outside of the vehicle.

  According to this, since the signal in which the heartbeat is emphasized can appear in the correlation value of each converted signal obtained by converting each signal received by the plurality of receiving units according to the phase, it is possible to obtain the heartbeat with high accuracy. obtain.

  For example, the processing unit may perform the conversion in (a) by calculating so that the phase angle of each of the electromagnetic wave signals is zero.

  Thereby, since the component of the human body movement due to the heartbeat appearing in the signal received by the receiving unit is emphasized, it is possible to acquire the heartbeat with high accuracy.

  Further, for example, the transmission unit and the plurality of reception units may be located below a seating surface on which a user is seated in the vehicle.

  Thereby, a transmission part will irradiate a user with electromagnetic waves from the downward direction of the seated user. In this case, the reception direction of the reflected wave from the user received by the reception unit is substantially along the vertical direction, and is not aligned with the traveling direction of the vehicle that is generally horizontal, but is substantially orthogonal to the traveling direction. For this reason, the influence of the body movement in the horizontal direction of the user mainly caused by the acceleration / deceleration of the vehicle is reduced to some extent, and the signals received by the receiving unit (that is, time-series signals) have the phases of the respective moments aligned to some extent. Therefore, the phase conversion by the processing unit acts appropriately, and the heartbeat can be acquired with high accuracy. In addition, for seated users, since the movement of the buttocks, thighs, etc. close to the seating surface is relatively small with respect to the upper body with relatively much movement (vibration accompanying body movement and breathing), the seating surface Since the receiving unit is located below the heart rate, the heartbeat can be continuously and accurately acquired.

  Further, for example, the plurality of receiving units are spaced apart from each other and are disposed below the thighs of a user seated in the vehicle, and the processing unit obtains the correlation value in the (b) It is good also as calculating based on the time difference relevant to arrangement | positioning of a some receiving part. The time difference related to the arrangement of the plurality of receiving units may correspond to, for example, the time difference of the propagation of the pulse wave at each part of the human body associated with the heartbeat. Note that the pulse wave at each part of the human body becomes a vibration of the surface (human body surface) of each part and is reflected in the reflected wave.

  Thereby, the adjustment for aligning the timing related to the heartbeat in the signal received by each receiving unit becomes possible. Since the correlation value obtained by correlating the adjusted signals is an enhancement of the heartbeat signal, it is possible to obtain a heartbeat with high accuracy. Further, in the user's thigh, the pulse wave accompanying the heartbeat appears relatively strongly in the vibration of the human body surface than the buttocks. Can be obtained.

  In addition, for example, the plurality of reception units include a first reception unit disposed below a first part of a thigh of one leg of the user seated in the vehicle, and the first of the thigh. A second receiver disposed below a second portion closer to the knee than the portion; a third receiver disposed below a portion of the thigh between the first portion and the second portion; A first distance between the first receiver and the second receiver is greater than a second distance between the first receiver and the third receiver, and the processor In (b), the first correlation value between the first converted signal obtained by converting the signal received by the first receiver and the second converted signal obtained by converting the signal received by the second receiver. The correlation value is based on the first converted signal, the second converted signal, and a first time difference corresponding to the first distance. A second correlation value that is a correlation value between the first converted signal and the third converted signal obtained by converting the first received signal and the signal received by the third receiving unit is calculated as the first converted signal and the third converted signal. Based on the converted signal and a second time difference that is shorter than the first time difference and corresponding to the second distance, in (c), the user's heart rate is calculated as the first correlation value and the second time difference. It is good also as acquiring using a correlation value.

  This corresponds to each of the distance between the first part and the second part and the distance from the first part to the first part and the second part where the propagation time of the pulse wave accompanying the heartbeat is different. Thus, based on each time difference where the time difference is set shorter as the distance is shorter, it is possible to adjust for aligning the timing related to the heartbeat in the signal received by each receiving unit, and it is possible to obtain a heartbeat with high accuracy. .

  In addition, for example, the plurality of receiving units include a first receiving unit and a second receiving unit positioned in front of the vehicle with respect to the first receiving unit, and the processing unit in the (b), The correlation value between the first converted signal obtained by converting the signal received by the first receiving unit and the second converted signal obtained by converting the signal received by the second receiving unit is expressed as the first converted signal and the first converted signal. It is good also as calculating based on the time difference relevant to the distance between 2 conversion signals and the said 1st receiving part and the said 2nd receiving part, and acquiring the said user's heartbeat using the said correlation value.

  Thereby, based on the time difference related to the distance between the receiving units, adjustment for aligning the timing related to the heart rate in the signals received by each receiving unit can be performed, and it is possible to obtain a heart rate with high accuracy.

  In addition, for example, in (b), the processing unit may calculate the time difference using a plurality of signals received by the plurality of receiving units while the vehicle is stopped.

  As a result, when the vehicle is stopped, the user's body movement, vibration, etc. are relatively small compared to when the vehicle is running, so the timing difference related to the heartbeat in the signals received by each receiving unit can be acquired with relatively high accuracy. The time difference can be calculated appropriately. Then, the calculated time difference is used for calculating the correlation value related to the signal received by each receiving unit while the vehicle is stopped or traveling, so that it is possible to obtain a heartbeat with high accuracy.

  In addition, for example, in (b), the processing unit calculates the time difference using a plurality of signals received by the plurality of receiving units when a change in acceleration of the vehicle exceeds a threshold value. Also good.

  Thus, for example, when the accelerator pedal or the brake pedal is depressed and the vehicle is greatly accelerated or decelerated, the body movement of the user of the vehicle becomes relatively small. Therefore, the timing related to the heartbeat in the signal received by each receiving unit Difference can be obtained with relatively high accuracy, and the time difference can be calculated appropriately. Then, by calculating the correlation value related to the signal received by each receiving unit using the calculated time difference, it is possible to obtain a heartbeat with high accuracy.

  In addition, for example, in (b), the processing unit calculates a heart rate template signal corresponding to signals received by each of the plurality of receiving units while the vehicle is stopped, and the heart rate template signal, Calculating the correlation value between the plurality of converted signals based on the plurality of converted signals calculated using the plurality of signals received by the plurality of receiving units during traveling of the vehicle and the time difference. It is good.

  As a result, when the vehicle is stopped, the user's body movement, vibration, etc. are relatively small compared to when the vehicle is running, so that the characteristics indicating the user's heartbeat appear relatively sufficiently from the signals received by each receiving unit. It is possible to calculate a heartbeat template signal. The calculated heart rate template signal can be used, for example, for emphasizing the heart rate component in the converted signal related to the signal received by each receiving unit while the vehicle is running. Acquisition may be possible.

  In addition, for example, in (b), the processing unit calculates a heartbeat template signal corresponding to a signal received by each of the plurality of receiving units when a change in acceleration of the vehicle exceeds a threshold value, The correlation value between the plurality of conversion signals may be calculated based on the heartbeat template signal, the plurality of conversion signals, and the time difference.

  As a result, the body movement of the user of the vehicle becomes relatively small when the vehicle is greatly accelerated or decelerated, and the characteristics indicating the user's heartbeat appear relatively sufficiently from the signals received by each receiving unit. The heartbeat template signal can be calculated. The calculated heart rate template signal can be used in a timely manner, for example, for emphasizing the heart rate component in the converted signal related to the signal received by each receiving unit, so that it is possible to acquire a heart rate with high accuracy. obtain.

  Further, for example, the plurality of receiving units may be disposed below the thighs of the legs farther from the accelerator pedal provided in the vehicle among the legs of the user seated in the vehicle.

  As a result, in the seated user, the body movement of the thigh of the leg farther from the accelerator pedal is relatively small with respect to the upper body, the leg (foot) of stepping on the accelerator pedal of the user of the vehicle, etc. Since the receiving unit is positioned below the thigh of the leg far from the accelerator pedal, the heartbeat can be continuously and accurately acquired.

  Further, for example, the output in (d) by the processing unit may include transmitting a control signal generated according to the heartbeat of the user to the vehicle.

  Thereby, for example, when the user's heartbeat is abnormal, the vehicle device can receive the control signal and control the vehicle (for example, running control such as stopping the vehicle running on the road on the shoulder). Can be.

  Further, for example, the output in (d) by the processing unit may include presenting information generated according to the user's heartbeat to the user. The information generated according to the heartbeat is, for example, a heart rate, a heartbeat waveform, a heartbeat interval, a physical condition estimated from the heartbeat, advice based on the heartbeat, and the like.

  Thereby, the user can know the information generated according to the heartbeat. Further, for example, the user can learn a posture suitable for heart rate measurement by confirming the presentation of the information, and as a result, the heart rate can be measured more appropriately.

  For example, the transmission unit may transmit microwaves, and the plurality of reception units may receive microwaves.

  As a result, in microwaves such as millimeter waves, a relatively large number of components reflecting the heartbeat appear in the signal received by the receiving unit, so that it is possible to accurately measure the heartbeat. Further, since the microwave of the electromagnetic wave has a relatively short wavelength, an antenna used for transmission and reception can be formed relatively small.

  For example, the processing unit may acquire the heartbeat by extracting a peak from the time-series data of the correlation value in (c).

  Thereby, the heartbeat (for example, heartbeat timing etc.) can be acquired appropriately by extracting the peak of the time series data in which a plurality of correlation values between the instantaneous signals are connected.

  A heartbeat acquisition method according to an aspect of the present disclosure is a heartbeat acquisition method for acquiring a heartbeat of a user of a vehicle, wherein (a) an electromagnetic wave is transmitted to the user in the vehicle, and (b) the user The reflected electromagnetic waves are received using a plurality of receiving devices, and (c) a plurality of converted signals using the phases of the signals of the plurality of electromagnetic waves received by the plurality of receiving devices. (D) calculating a correlation value between the plurality of converted signals, and (e) acquiring the heartbeat of the user using the correlation value. Acquisition of the user's heartbeat can be implemented, for example, by storing information indicating the user's heartbeat in a storage medium such as a memory in a certain device. The storage medium may be taken out from the device and utilized, or the device may output (presentation, transmission, etc.) information based on information indicating the user's heartbeat that is the content of the storage medium. .

  Thereby, since a signal in which the heartbeat is emphasized can appear in the correlation value of each converted signal obtained by converting each signal received by the plurality of receiving apparatuses according to the phase, it is possible to obtain a heartbeat with high accuracy.

  Note that these comprehensive or specific various aspects include one or more combinations of an apparatus, a system, a method, an integrated circuit, a program (computer program), a computer-readable recording medium, and the like.

  Hereinafter, embodiments of a heartbeat acquisition system according to the present disclosure will be described with reference to the drawings. Any of the embodiments shown here is merely an example. Therefore, numerical values, shapes, materials, components, arrangement and connection forms of components, and steps and order of steps shown in the following embodiments are merely examples, and are not limited. Among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims can be arbitrarily added. Each figure is a mimetic diagram and is not necessarily illustrated strictly.

(Embodiment 1)
A heartbeat acquisition system 100 according to the present embodiment will be described. FIG. 1 is a block diagram showing a configuration of a heartbeat acquisition system 100 according to the present embodiment.

  A heartbeat acquisition system 100 is a system for acquiring a heartbeat of a user of a vehicle, and as shown in the figure, a transmission unit 101, a plurality of reception units (reception unit 102A and reception unit 102B), and a processing unit 110. The processing unit 110 includes a phase conversion unit 111, a time difference setting unit 112, a correlation calculation unit 113, a heart rate estimation unit 114, and an information presentation unit 115.

  In the heartbeat acquisition system 100, the transmission unit 101 transmits electromagnetic waves (microwaves) to the user, the reflected waves from the user that reflected the electromagnetic waves are received by the plurality of reception units 102A and 102B, and the received signals are processed. In unit 110, each converted signal is calculated by phase conversion corresponding to the phase of each signal, a correlation value between the converted signals is calculated, the user's heartbeat is acquired using the correlation value, and the user's heartbeat is determined Output.

  Hereinafter, each component of the heart rate acquisition system 100 will be described in detail.

(Transmitter 101)
The transmission unit 101 is used while being positioned in a vehicle, and irradiates (that is, transmits) electromagnetic waves to a user. Specific hardware of the transmission unit 101 is a transmission circuit including a microstrip antenna (patch antenna), an analog circuit, and the like. Hereinafter, the transmission part 101 demonstrates as an example irradiating a user with a microwave (for example, millimeter wave).

(Receiver 102A, 102B)
The receiving units 102A and 102B as an example of a plurality of receiving units are used in a position on the vehicle, and the reflected waves from the electromagnetic waves (for example, microwaves such as millimeter waves) emitted from the transmitting unit 101 are reflected by the user. Receives a wave (that is, receives a signal corresponding to a reflected wave). Specific hardware of the receiving units 102A and 102B is a receiving circuit including a microstrip antenna, an analog circuit, and the like.

  FIG. 2 shows an example of the transmission unit 101 and the reception units 102A and 102B. FIG. 2A shows the appearance of the transmission unit 101 and the reception unit 102A. The receiving unit 102B is the same as the receiving unit 102A. FIG. 2B shows an example of the arrangement of the transmission unit 101 and the reception units 102A and 102B. In this example, the transmitting unit 101 and the receiving units 102A and 102B are arranged inside a seat 12 in a vehicle seat (seat) 10 such as a driver's seat of an automobile, for example. Therefore, the transmission unit 101 irradiates the user with electromagnetic waves from below the user seated on the seat 10, and the reflected waves from the user reflecting the electromagnetic waves are received by the receiving units 102A and 102B located below the user. It becomes. In this case, the receiving direction of the reflected wave from the user received by the receiving unit 102A (or the receiving unit 102B) is not aligned with the traveling direction of the vehicle, and mainly the body movement of the user in the horizontal direction caused by the acceleration / deceleration of the vehicle. The signal received by the receiving unit 102A (or the receiving unit 102B) (that is, the time series signal) has a certain phase in each phase. Therefore, the phase conversion by the processing unit 110 described later is appropriate. Can act on. In addition, although the transmission part 101 and the receiving parts 102A and 102B showed the example arrange | positioned inside the seat part 12 of the seat 10 of a vehicle, it is useful to be located under the seat surface on which a user sits. The seating surface is an upper surface of a member where a user is seated in the vehicle, and is an upper surface of a seatable structure such as a seat 12 of the seat 10 or a cushion placed on the seat 10. This seatable structure may be integrated with the transmitter 101 and the receivers 102A and 102B themselves. For example, the user's buttocks, thighs, and the like can be placed on the seating surface. For this reason, the transmitting unit 101 and the receiving units 102A and 102B are provided inside the seat 12 of the seat 10, the surface of the seat 12 of the seat 10, the interior of the cushion placed on the seat 10, the surface of the cover of the seat 10, and the back surface. It is useful to be arranged in the same manner.

  FIG. 2C illustrates the arrangement of the transmission unit 101 and the reception units 102A and 102B in the seat 10 of FIG. 2B in a plan view as viewed from above the vehicle. In FIG. 2C, an accelerator pedal 21, a brake pedal 22, and a handle (steering wheel) 23 are additionally shown in addition to the seat 10 of a vehicle such as an automobile. In the example of FIG. 2 (c), a portion of the seat 12 of the vehicle seat 10 away from the backrest 11 of the seat 10 (that is, a portion of the seat on the front side of the vehicle), ) In the left-right direction away from the accelerator pedal 21, the transmitter 101 and the receivers 102A and 102B are arranged. Note that the front of the vehicle is, for example, one direction in which the vehicle travels mainly by wheels, and a user who drives an automobile, for example, sits forward. The receiving units 102A and 102B are arranged away from each other on the portion of the two legs of the user seated on the seat 10 where the thigh of the leg far from the accelerator pedal 21 is placed. 102B is located in front of the vehicle from the receiving unit 102A. That is, the receiving unit 102A is disposed below the first part of the thigh of one leg of the user seated in the vehicle, and the receiving unit 102B is closer to the user's knee than the first part of the thigh. It will be placed below the two parts.

  The slight vibration of the human body surface accompanying the heartbeat is easier to detect on the back side of the thigh including the back of the knee than the buttocks. Therefore, in the heartbeat acquisition system 100, it is useful to arrange the receiving units 102A and 102B below the thighs rather than below the buttocks so as to be suitable for receiving reflected waves from the thighs.

  Further, in a vehicle having the accelerator pedal 21 and the seat 10 arranged as shown in FIG. 2C, the user who operates the vehicle while sitting on the seat 10 operates the accelerator pedal with the right leg. There is less movement of the left leg compared to the right leg. Therefore, in the heartbeat acquisition system 100, it is useful to arrange the receiving units 102A and 102B on the left half of the seat 12 so as to be suitable for receiving a reflected wave from the thigh of the left leg.

  The receiving units 102A and 102B may be arranged other than the example described above. For example, the receiving units 102A and 102B may be disposed below the left leg thigh and the right leg thigh for a user seated on the seat 10 or the like. You may arrange | position so that each receiving part may be located in a distributed manner. Further, in FIGS. 2B and 2C, configuration examples for both the receiving unit 102 </ b> A and the receiving 102 </ b> B to receive a reflected wave that is an electromagnetic wave transmitted by one transmitting unit 101 reflected by a user. Although shown, it is good also as providing a transmission part for every receiving part.

  The reflected wave received by the receiving unit 102A (or the receiving unit 102B) when the microwave emitted from the transmitting unit 101 is reflected by the surface of the user's human body seated on the seat 10 is expressed by the following equation.

・・・（式１）

... (Formula 1)

  Here, i and q are in-phase and quadrature components. V is a direct wave, clutter from the periphery, a direct current component from the surface of a stationary human body, or the like. When the vibration associated with the heartbeat occurs on the surface of the user's human body, the amplitude A, the Doppler signal fd, and the phase φ change and appear as the AC component of the second term of Equation 1. In the case of a continuous wave (CW) type microwave, since the direct current component is large, it is useful to suppress the direct current component by an analog circuit or digital processing and extract the heartbeat component from the alternating current component.

  The receiving circuits of the receiving units 102A and 102B include, for example, a 24.1 GHz continuous wave (CW) type microwave sensor. Further, in order to extract the heartbeat change while suppressing the direct current component of the reflected wave, the receiving circuits of the receiving units 102A and 102B use the high-pass filter as an AC coupling module in the analog circuit. The cutoff frequency of AC coupling in the high pass filter is, for example, 6 Hz. The influence of the first term of Equation 1 is suppressed by the high-pass filter, and the change accompanying the heartbeat mainly occurs as the amplitude A (t). For this reason, the receiving units 102A and 102B extract a signal corresponding to the second term part of Equation 1 as a received signal obtained from the reflected wave, and the heartbeat acquisition system 100 extracts a heartbeat from the received signal in the processing unit 110 ( get. The heartbeat can be acquired by digital processing, for example, based on data indicating the received signal.

(Processing unit 110)
The processing unit 110 calculates each converted signal by phase conversion corresponding to the phase of each signal of the receiving unit 102A and the receiving unit 102B, calculates a correlation value between the converted signals, and acquires a user's heartbeat using the correlation value Then, an output corresponding to the heartbeat of the user is performed. The processing unit 110 can be configured by, for example, a processor (microprocessor), a memory, and the like. Acquisition of the user's heartbeat in the processing unit 110 can be performed, for example, by storing information indicating the user's heartbeat in a storage medium such as a memory. The phase conversion unit 111, the time difference setting unit 112, the correlation calculation unit 113, and the heart rate estimation unit 114 in the processing unit 110 are realized by, for example, a processor that executes a program stored in a memory. The information presentation unit 115 is realized by a processor that executes a program stored in a memory, for example.

(Phase converter 111)
The phase conversion unit 111 calculates and corrects the phase angle of the signal in which the vibration of the human body surface corresponding to the heartbeat appears from the received signal obtained from the reflected wave in each of the receiving unit 102A and the receiving unit 102B, and corrects the converted signal. Generate. The phase angle correction will be described with reference to FIG.

  FIG. 3A shows a state in which the human body surface 13 generates vibrations in the front and rear (vibrations in the A direction and the B direction in the drawing) with respect to the receiving unit (receiving unit 102A and the like) according to the heartbeat. FIG. 3B shows a graph showing the temporal change of the amplitude. In the portion 14 of this graph with the horizontal axis representing the time axis and the vertical axis representing the amplitude (absolute value), the movement in the B direction occurred following the movement of the surface 13 in the A direction in FIG. Appears. In general, a Doppler sensor using a microwave detects the movement of an object from the change in amplitude.

  However, when a received signal obtained by vibration due to an actual heartbeat is represented in a complex space, an amplitude is generated with a certain phase angle. FIG. 3C is a diagram showing a reception signal in which vibration of the human body surface corresponding to the heartbeat appears in a complex space (complex number plane) including the I axis and the Q axis. As shown in FIG. 3C, the received signal as a vector having an I (in-phase) component and a Q (quadrature) component has a phase angle θ with respect to the I axis, and the amplitude is in the A direction. It occurs in the B direction. Therefore, when this phenomenon is viewed from the direction C of the angle orthogonal to the phase angle θ, it can be seen that the movement in the A direction is opposite to the movement in the B direction. On the other hand, since signals other than the heartbeat, such as noise, are random signals, there is little influence on this phenomenon when viewed from the direction C of the angle orthogonal to the phase angle θ. Is emphasized. Therefore, the phase conversion unit 111 calculates a phase angle for each window (unit period) having a predetermined window length on the time axis, and sets the phase angle of the received signal to zero based on the received signal obtained from the reflected wave. By performing a rotation calculation so as to make correction, a converted signal obtained by converting (that is, phase converting) the received signal is calculated. A portion 15 of the graph of FIG. 3C shows an image of the converted signal in which the heartbeat signal is emphasized with respect to the portion 14 of the graph of FIG.

  In the case of a general Doppler sensor, since the distance between the object and the transmission / reception unit (transmission unit and reception unit) varies greatly, the phase angle varies greatly with the movement of the object. However, in the heartbeat acquisition system 100 according to the present embodiment, the thigh, buttocks, and knees of the user's human body from the transmission / reception units (the transmission unit 101 and the reception units 102A and 102B) installed in the seat 12 of the seat. The thighs, buttocks, knees, etc. are relatively stationary and stationary (ie, stationary) when the user is seated. The distance between the transmitter and the transmitter / receiver is kept substantially constant. For this reason, unlike a general Doppler sensor, the phase angle is kept at a relatively constant value, and therefore, the phase angle can be calculated to the extent that adjustment is performed for each predetermined window length.

  Hereinafter, correction of the received signal in the rotation calculation for phase conversion in the phase conversion unit 111 will be described with reference to FIG.

  FIG. 4A shows a temporal change in the magnitude of the amplitude of the received signal, which is a time-series signal, as in FIG. 3B. For example, the phase conversion unit 111 calculates the phase angle while shifting the window (for example, shifting by 600 ms) by setting the window length to 1200 ms that generally includes one or more beats of a human heartbeat. The phase angle is calculated by, for example, a linear approximation method. The received signals that are time-series signals in FIG. 4A are provided with windows W1, W2, and W3 for partially calculating the phase angle.

  In the period of the window W1, the angle θ1 is calculated as the phase angle. Therefore, by multiplying the received signal by a reverse rotation matrix of angle θ1 (rotation matrix of minus θ1), a signal in which the direction of vibration corresponding to the heartbeat appears can be obtained substantially parallel to the I axis. . Similarly, in the period of the window W2, the angle θ2 is calculated as the phase angle, and in the period of the window W3, the angle θ3 is calculated as the phase angle. By multiplying the rotation matrix corresponding to each calculated phase angle, the received signal becomes a signal in which the heart rate is emphasized in the I component. Therefore, the phase conversion unit 111 calculates, as a conversion signal, an I component as a result of multiplying the received signal by a rotation matrix corresponding to the calculated phase angle for each window.

  Since the phase angle changes depending on the positional relationship (distance and angle) between the human body surface and the receiving unit 102A (or receiving unit 102B), the phase angle is repeatedly calculated at a predetermined timing, and sequentially according to the newly calculated phase angle. Thus, it is useful to calculate the converted signal by correcting the received signal. Here, an example in which the window is shifted every 600 ms has been described. On the other hand, when the posture of the user seated on the vehicle does not change, the phase angle may be maintained at a substantially constant value, so that the frequency of calculating the phase angle may be suppressed. For example, in consideration of the fact that the position of the leg on the seating surface of the seated user does not change much while the vehicle is running, the rotation calculation for calculating the conversion signal is performed using the same phase angle from the start to the stop of the run. The phase angle may be newly calculated each time the traveling vehicle stops with a signal from a traffic light (traffic signal) or the like. Thereby, the amount of calculation for calculation of the conversion signal in the phase converter 111 can be reduced.

(Correlation calculation unit 113)
Correlation calculation section 113 performs correlation calculation for signals obtained from a plurality of reception sections (reception sections 102A and 102B). The reception signal from each of the reception unit 102A and the reception unit 102B used by the correlation calculation unit 113 is a converted signal obtained by phase-converting the reception signal by the phase conversion unit 111. The correlation calculation unit 113 calculates a correlation value indicating a correlation in a section of a predetermined time length (for example, 1000 ms) between the converted signals, which are time-series signals corresponding to the reception signals of the respective reception units, by the following equation 2, and the calculation The correlation value obtained is set as the correlation value at the time of the section. Then, the correlation calculation unit 113 calculates the correlation value at each time while shifting the interval (for example, by 10 ms). The correlation value is calculated by the following formula, for example.

・・・（式２）

... (Formula 2)

  In this equation 2, the correlation value Z (n) is calculated by calculating the inner product of two time series signals Xn and Yn, and is normalized by dividing by the magnitude of Xn and Yn. There is no need to divide by size.

  Hereinafter, an example of calculating the correlation value will be described with reference to FIG. (A) of FIG. 5 shows the time change of the converted signal (first converted signal) obtained by converting the received signal from the receiving unit 102A by the phase converting unit 111. FIG. 5B shows a temporal change of the converted signal (second converted signal) obtained by converting the received signal from the receiving unit 102B by the phase converting unit 111. When the first conversion signal is Xn and the second conversion signal is Yn, the correlation value can be calculated by Equation 2. For example, the inner product of the first converted signal and the second converted signal in a predetermined section (for example, tn−2, tn−1, tn, tn + 1, tn + 2) with the time tn interposed therebetween is set as the correlation value of the time tn. Then, a correlation value is calculated for each time. For example, for time tn + 1, the inner product of the first converted signal and the second converted signal in the section (for example, tn−1, tn, tn + 1, tn + 2, tn + 3) is calculated as the correlation value at time tn + 1. The time series data of the correlation value calculated in this way is shown in FIG.

  The converted signal corresponding to each of the receiving unit 102A and the receiving unit 102B includes a heartbeat signal in the same cycle. On the other hand, noise is also mixed at random. Therefore, the correlation calculation unit 113 performs a correlation calculation to obtain a correlation between the two converted signals, thereby enabling acquisition of a signal in which random noise is suppressed and the heartbeat signal is emphasized (that is, time-series data of correlation values). It becomes. When three or more receiving units are used in the heart rate acquisition system 100, a correlation value may be calculated by taking a correlation between three or more converted signals, or converted for each set of two receiving units. The correlation value may be calculated by taking the correlation between the signals and statistically processing the result (for example, averaging).

  Further, the correlation calculation unit 113 adjusts the time difference of propagation of pulsation due to the heartbeat to each part of the human body, which is set by the time difference setting unit 112 described below, and obtains a correlation.

(Time difference setting unit 112)
The time difference setting unit 112 sets a time difference for shifting each conversion signal when the correlation calculation unit 113 obtains a correlation. The vibration generated on the surface of each part of the human body (the human body surface) due to the propagation of the heartbeat has a time difference depending on the part. For example, the first part of the thigh close to the user's buttocks seated on the seat 12 of the seat 10 in FIG. 2C is accompanied by a heartbeat prior to the second part of the thigh close to the knee. Vibration occurs. For this reason, the receiving unit 102B disposed below the second part close to the user's knee receives a receiving signal 102B disposed below the first part close to the buttocks in the user's thigh. The vibration associated with the heartbeat appears at a slightly earlier timing than the received signal to be acquired. Therefore, the time difference setting unit 112 may set a time difference (for example, 5 ms) in advance in relation to the arrangement of the receiving unit 102A and the receiving unit 102B. In the correlation calculation unit 113, based on the time difference set by the time difference setting unit 112, the first conversion signal and the second conversion signal, which are time series signals, are shifted by the time difference to obtain an inner product (for example, at the time tn The correlation value is calculated by taking the inner product by associating one converted signal with the second converted signal at time tn + 5 ms). By setting the time difference and taking the correlation in this way, noise in the same phase is originally suppressed, and the heartbeat signal is further emphasized. The setting of the time difference by the time difference setting unit 112 is realized by storing the time difference in a storage medium such as a memory, for example, and the correlation calculation unit 113 reads the time difference from the storage medium to obtain the time difference when taking the correlation. Is used.

  Since there is a certain relationship between the distance between the parts and the time difference in propagation of pulsation due to heartbeats between local parts such as the hip part and knee part in the thigh of one leg, the time difference setting unit 112 The time difference may be set in advance in relation to the distance between the receiving unit 102A and the receiving unit 102B (for example, the interval between the receiving units).

  An example in which the time difference is set in relation to the distance between a plurality of receiving units arranged on the seat of the vehicle seat will be described with reference to FIG. For example, FIG. 6A illustrates an example in which the distance between the receiving unit 102A and the receiving unit 102B disposed on the seat 12 is 20 cm. In this example, as shown in the graph below, a signal in which vibration corresponding to the heartbeat appears with a time difference of 5 ms is obtained. FIG. 6B illustrates an example in which the distance between the receiving unit 102A and the receiving unit 102B disposed on the seat 12a is 40 cm. In this example, as shown in the graph below, a signal in which vibration corresponding to the heartbeat appears with a time difference of 10 ms is obtained. FIG. 6C illustrates an example in which the distance between the receiving unit 102A and the receiving unit 102B disposed on the seat 12a is 40 cm, and the distance between the receiving unit 102A and the receiving unit 102C is 20 cm. As described above, the amount of deviation in the timing of the vibration signal associated with the heartbeat differs between the case where the distance between the receiving parts is 20 cm and the case where the distance between the reception parts is 40 cm. As shown in (a) and (b) of FIG. 6, the greater the distance between the receiving units, the greater the difference in vibration timing associated with the heartbeat. Therefore, the time difference setting unit 112 may set the time difference in advance in relation to the distance between the receiving units, for example, 5 ms when the distance between the receiving units is 20 cm, 10 ms when the distance is 40 cm, or the like. Further, as shown in FIG. 6C, when there are three receiving units, the time difference may be set in advance in consideration of the arrangement relationship of the receiving units. For example, as shown in FIG. 6C, the distance between the receiving unit 102A and the receiving unit 102B is 40 cm, and a signal in which vibration corresponding to the heartbeat appears with a time difference of 10 ms corresponding to this distance is obtained. To do. In this case, for the receiving unit 102C arranged between the receiving unit 102A and the receiving unit 102B, a time shorter than 10 ms, for example, if the distance between the receiving units is 20 cm, 5 ms corresponding to this distance. It is useful to set the time difference to obtain the correlation. In addition, the time difference setting unit 112 may set the time difference in advance corresponding to the arrangement of the receiving units in the left-right direction of the user seated on the vehicle.

  In general, the length of a seat portion in a vehicle seat varies in the front-rear direction. Depending on the circumstances of the structure of the seats having various lengths, the arrangement modes of the plurality of receiving units (intervals between the receiving units, etc.) can be varied. However, when the time difference setting unit 112 appropriately sets the time difference according to the distances of the plurality of receiving units, the correlation calculation unit 113 obtains a correlation between the signals shifted by the time difference. The timing of the signals is more consistent and the vibration signal associated with the heartbeat is enhanced. Thereby, it may be possible to detect heartbeat timing with high accuracy.

(Heart rate estimation unit 114)
The heartbeat estimation unit 114 estimates (acquires) a heartbeat based on the correlation value calculated by the correlation calculation unit 113. The heart rate estimation will be described with reference to FIG. (A) of FIG. 7 shows the time change of the 1st conversion signal as a result of having performed phase conversion in the phase conversion part 111 with respect to the received signal which 102A of receiving parts received. FIG. 7B shows a temporal change of the second converted signal as a result of performing phase conversion by the phase converting unit 111 on the received signal received by the receiving unit 102B. FIG. 7C shows a signal obtained by shifting the second converted signal by a time difference of 5 ms based on the setting by the time difference setting unit 112. (D) of FIG. 7 shows the correlation value which is time series data as a result of having obtained the correlation between the signals shown in (a) and (c) of FIG. By extracting, for example, a peak (white circle in the figure) from the correlation value shown in (d) of FIG. 7, the heartbeat timing is obtained. As described above, the heart rate estimation unit 114 estimates (acquires) a heart rate (heart rate interval, heart rate, etc.) by extracting a correlation value peak or the like. For example, the heartbeat interval is a heartbeat timing interval, and the heart rate is the number of peaks within a predetermined time (or the reciprocal of the heartbeat interval). The heart rate estimation unit 114 may calculate the heart rate by performing frequency analysis on the time-series data of the correlation value. In addition, the heart rate estimation unit 114 refers to information related to a correspondence relationship between a predetermined heart rate and physical condition, health condition, stress condition, and the like, and based on the acquired user heart rate, the user's physical condition and health condition The stress state or the like may be estimated.

(Information presentation unit 115)
The information presentation unit 115 presents information related to the heartbeat to the user by displaying the information on the heartbeat acquisition system 100, for example. The heartbeat acquisition system 100 includes a user interface device for presenting information to the user, such as a display and a speaker, and the information presentation unit 115 controls the user interface device to thereby provide the user with a heartbeat via the user interface. Present information. The information related to the heartbeat presented by the information presenting unit 115 is information generated according to the heartbeat acquired by the heartbeat estimating unit 114. For example, the heart rate, the heartbeat waveform, the heartbeat interval, the physical condition estimated from the heartbeat, and the health condition , Psychological state (stress state, etc.), advice to the user based on heart rate, and the like. The information presenting unit 115 can present information related to heartbeats, for example, via a display or the like provided in the heartbeat acquisition system 100 installed at a position that can be viewed by a user who drives the vehicle. FIG. 8 shows a display screen 115 a showing the heart rate estimated by the heart rate estimating unit 114 as a display example by the information presenting unit 115. Note that the information presentation unit 115 presents information about the heartbeat to the user is not limited to display on the display, and may be performed by any method (for example, voice output of the information by a speaker).

(Heart rate acquisition method)
Hereinafter, the operation of the heartbeat acquisition system 100 that performs the heartbeat acquisition method will be described with reference to the flowchart of FIG. 9.

  The transmission unit 101 transmits a microwave (step S101). A plurality of reception units (reception unit 102A and reception unit 102B) receive reflected waves (microwaves) that are reflected on the surface of the human body of the user seated on the vehicle (step 102A and reception unit 102B). S102).

  The phase conversion unit 111 calculates the phase angle of the reception signal for each reception signal received by each of the plurality of reception units (step S103), and calculates the conversion signal by correcting the phase of the reception signal according to the phase angle. (Step S104).

  The time difference setting unit 112 sets a time difference for obtaining a correlation between the converted signals calculated in step S104 (step S105). The correlation calculation unit 113 shifts the time difference set in the time difference setting unit 112 and calculates a correlation value indicating the correlation between the converted signals (step S106).

  The heartbeat estimation unit 114 extracts a peak from the correlation value, which is time series data calculated by the correlation calculation unit 113, and acquires a heartbeat (for example, information such as a heart rate) (step S107). And the information presentation part 115 presents the information (for example, information, such as a heart rate) produced | generated according to the heartbeat acquired by the heartbeat estimation part 114 (step S108).

(Example of data related to heart rate acquisition)
Hereinafter, heartbeat acquisition in the heartbeat acquisition system 100 will be described using data obtained by using the heartbeat acquisition system 100.

  FIG. 10 is a diagram in which each instantaneous received signal related to the reflected wave from the thigh of the user seated on the seat received by the receiving unit 102A installed on the seat of the vehicle seat is plotted on a complex plane. . From the figure, it can be seen that the received signal has a phase angle θ.

  FIG. 11 is a diagram in which the phase angle θ of the received signal shown in FIG. 10 is rotated so as to be zero. FIG. 12 is a graph showing the I component of the received signal after rotation shown in FIG. 11 in time series.

  FIG. 13 is a graph obtained by calculating the correlation between the signal obtained from the above-described receiving unit 102A and the signal obtained separately from the receiving unit 102B. By taking the correlation, it can be seen that the vibration of the thigh (back of the knee) caused by the heartbeat is extracted with more emphasis.

  FIG. 14 is a graph comparing the heartbeat interval (white square) of the electrocardiograph acquired in synchronization with the heartbeat interval (black circle) acquired by the heartbeat acquisition system 100 by transmitting and receiving microwaves. From the same figure, it can be seen that the heartbeat interval acquired by the heartbeat acquisition system 100 substantially matches the heartbeat interval acquired by the electrocardiograph.

(Embodiment 2)
In the heartbeat acquisition system 100 according to Embodiment 1 described above, an example is shown in which the time difference setting unit 112 sets in advance the time difference used when obtaining correlation between signals corresponding to each of a plurality of receiving units. In the present embodiment, the heart rate acquisition system 100 is partially modified, and the time difference to be used for correlation is calculated based on the reception signals obtained by the receiving unit 102A and the receiving unit 102B, and the time difference is set. A heartbeat acquisition system 100A configured to perform the above will be described.

  FIG. 15 is a block diagram showing a configuration of a heartbeat acquisition system 100A according to the present embodiment. As shown in the figure, the heartbeat acquisition system 100A includes a transmission unit 101, reception units 102A and 102B, and a processing unit 110A. The processing unit 110A includes a phase conversion unit 111, a feature point calculation unit 116, a time difference setting unit 112A, a correlation calculation unit 113, a heartbeat estimation unit 114, and an information presentation unit 115. In addition, about the structure similar to Embodiment 1 (refer FIG. 1), the code | symbol same as FIG. 1 is attached | subjected in FIG. 15, and description is abbreviate | omitted.

  In the heartbeat acquisition system 100A, each conversion signal is converted into a phase conversion in accordance with the phase of each signal in the processing unit 110A from each reception signal received by the plurality of reception units 102A and 102B of the reflected wave from the user who reflected the electromagnetic wave. By calculating and using the time difference between the converted signals, the correlation value between the converted signals is calculated, the user's heartbeat is acquired using the correlation value, and an output corresponding to the user's heartbeat is performed. The processing unit 110A is the same as the processing unit 110 shown in the first embodiment, unless otherwise described here.

(Feature point calculation unit 116)
The feature point calculation unit 116 calculates a feature point for each reception unit from the converted signal obtained by converting the reception signal received by each reception unit by the phase conversion unit 111. For example, based on the peak as the feature point Calculate heartbeat timing.

  The calculation of the heartbeat timing by the feature point calculation unit 116 will be described with reference to FIG. FIG. 16 shows various feature points extracted from the converted signal obtained by converting the received signal received by the receiving unit 102A.

  The heartbeat signal has a unique waveform. For this reason, the feature point calculation unit 116 calculates a series of feature points by extracting each of a plurality of predetermined waveform features from the converted signal. The feature point calculation unit 116 refers to, for example, a peak (white circle), a bottom (black circle) where the differential value is 0, and an inflection point (black triangle, white triangle) where the secondary differential value is 0 from the converted signal. Each feature point is calculated and one series of feature points arranged in the order of “bottom (black circle), inflection point (black triangle), peak (white circle), inflection point (white triangle), bottom (black circle)” ” The heartbeat is calculated, and the peak (white circle) is calculated as the heartbeat timing for one beat. Note that the peak calculation method is not limited to this. For example, threshold values may be provided for the values of feature points such as peaks and bottoms, and noise and heartbeats may be determined by comparison with the threshold values, or threshold values may be provided between the feature points. In addition, if the feature point by the second derivative is used, the heartbeat timing can be calculated with higher accuracy.

  FIG. 17 is a graph showing the I component of the converted signal as data obtained using the heartbeat acquisition system 100A in time series. Here, as feature points extracted using a threshold, peaks (white circles), A bottom (black circle) and an inflection point (black triangle, white triangle) are shown. The peak (white circle) indicates the heartbeat timing.

(Time difference setting unit 112A)
The time difference setting unit 112A sets a time difference (that is, a time difference by which each converted signal is shifted) to be correlated by the correlation calculation unit 113 from the difference in heartbeat timing calculated based on the signal received by each receiving unit. Setting of the time difference by the time difference setting unit 112A is realized by storing the time difference in a storage medium such as a memory, for example, and the correlation calculation unit 113 uses the time difference when taking the correlation by reading the time difference from the storage medium. To do.

  The time difference setting unit 112A calculates a time difference to be set, for example, from an average of heartbeat timing differences calculated based on signals received by each receiving unit in a predetermined section (eg, 3000 ms). Here, a description will be given using the example of FIG. (A) of FIG. 18 shows a temporal change of the first converted signal as a result of performing phase conversion by the phase conversion unit 111 on the reception signal received by the reception unit 102A. FIG. 18B shows a temporal change of the second converted signal as a result of performing phase conversion by the phase converting unit 111 on the received signal received by the receiving unit 102B. In the case of the example in FIG. 18, the difference in heartbeat timing is 7 ms, 5 ms, and 6 ms in order, so that the average of 6 ms is calculated and set as the time difference.

  Based on the time difference set by the time difference setting unit 112A, the correlation calculation unit 113 converts the first conversion signal and the second conversion signal, which are time series signals obtained from the reception signals received by the reception units 102A and 102B, into The correlation value is calculated by taking the inner product by shifting the time difference. FIG. 18C shows a signal obtained by shifting the second conversion signal by the time difference of 6 ms based on the time difference setting of the average value 6 ms calculated by the time difference setting unit 112. Moreover, (d) of FIG. 18 shows the correlation value which is time series data as a result of having obtained the correlation between the signals shown in (a) and (c) of FIG. By extracting a peak indicated by a white circle in (d) of FIG. 18, the heart rate estimating unit 114 acquires a heart rate (heart rate interval, heart rate, etc.).

  The time difference of the propagation of the heartbeat to each part of the surface of the human body of the user, to which each receiving unit captures vibration by receiving the reflected wave, varies depending on the individual or the posture. As described above, heartbeat acquisition system 100A according to the present embodiment calculates the time difference as appropriate, so that it is possible to acquire a heartbeat with high accuracy adapted to an individual.

(Embodiment 3)
Hereinafter, a template as information indicating characteristics of an individual's heartbeat by learning in a specific period in order to deform a part of the heartbeat acquisition system 100A according to the second embodiment and acquire the heartbeat more accurately by adapting to the individual. A heartbeat acquisition system 100B that collects and uses (that is, a heartbeat template signal indicating the characteristics of a heartbeat) will be described. The specific period is relatively low in noise when measuring vibration of the human body surface associated with a heartbeat, such as when the vehicle is stopped (for example, when the vehicle is not running, including when the engine is stopped, idling, etc.) It's time.

  FIG. 19 is a block diagram showing a configuration of a heartbeat acquisition system 100B according to the present embodiment. As shown in the figure, the heartbeat acquisition system 100B includes a transmission unit 101, reception units 102A and 102B, and a processing unit 110B. The processing unit 110B includes a phase conversion unit 111, a feature point calculation unit 116, a time difference setting unit 112A, a correlation calculation unit 113A, a heart rate estimation unit 114, an information presentation unit 115, a vehicle state detection unit 117, and a heart rate template storage unit 118. Have. In addition, about the structure similar to Embodiment 1, 2 (refer FIG. 1, FIG. 15), the code | symbol same as FIG. 1 or FIG. 15 is attached | subjected in FIG. 19, and description is abbreviate | omitted.

  In the heartbeat acquisition system 100B, when detecting whether the vehicle state is the stop state (that is, the running state), at the time of stoppage, the heartbeat template signal indicating the user's heartbeat information by the method shown in the second embodiment is generated. get. The heartbeat template signal is acquired for each receiving unit. When not stopped (that is, during running), template matching is performed on each signal obtained by reception by the receiving units 102A and 102B using the acquired heart rate template signal, which is similar to the heart rate template signal. Signal (that is, a signal having high correlation) is emphasized, and a signal that is not similar (that is, a signal having low correlation) is suppressed. Thereby, a signal in which a signal similar to the heartbeat template signal is emphasized is obtained from each receiving unit, and the processing unit 110B calculates a correlation value between the obtained signals and uses the correlation value to obtain the user's The heart rate is acquired, and output corresponding to the user's heart rate is performed. The processing unit 110B is the same as the processing unit 110A shown in the second embodiment except for points that are not particularly described here.

(Vehicle state detection unit 117)
The vehicle state detection unit 117 detects the traveling state of the vehicle. The vehicle state detection unit 117 detects whether the vehicle is stopped or running by acquiring a result of sensing by a sensor related to vehicle control such as an accelerator, a brake, and a handle. Further, the vehicle state detection unit 117 includes a sensor such as an acceleration sensor or acquires a sensing result from the sensor, thereby measuring a change in acceleration indicating vibration or the like, and stopping the vehicle based on the measurement result. It is good also as detecting the time, the time of driving | running | working, etc. The vehicle state detection unit 117 generates information related to the heartbeat template signal for each reception unit based on the feature point of the signal for each reception unit calculated by the feature point calculation unit 116 when the detected vehicle is stopped. Then, information related to the heartbeat template signal is stored in the heartbeat template storage unit 118. The heartbeat template storage unit 118 is realized in one area of a storage medium such as a memory, for example. The information related to the heartbeat template signal accumulated in the heartbeat template accumulation unit 118 is used in the correlation calculation unit 113A, and template matching is performed on the signal from each reception unit by the heartbeat template signal to emphasize the heartbeat. The correlation calculation unit 113A is obtained by adding a template matching function to the correlation calculation unit 113 described in the first embodiment.

  Here, generation of a heartbeat template signal and template matching will be described with reference to FIG. FIG. 20A shows a reception signal from the receiving unit 102A when the vehicle is stopped and when the vehicle is running. When the vehicle is stopped, since the vibration of the vehicle and the movement of the body of the user seated on the vehicle are small, the heartbeat appears strongly against noise in the signal, and the heartbeat signal can be detected with relatively high accuracy. On the other hand, during running, the vibration of the vehicle and the movement of the body increase, so noise is mixed in and the heartbeat signal is buried. Therefore, the vehicle state detection unit 117 identifies when the vehicle is stopped by detecting whether or not the vehicle is stopped. The time when the vehicle is stopped is a specific period for generating and accumulating the heartbeat template signal. When the vehicle stops, the vehicle state detection unit 117 detects a peak indicated by a white circle in FIG. 20A from the feature point of the signal for each reception unit calculated by the feature point calculation unit 116, and the peak A plurality of predetermined intervals before and after (for example, 1000 ms in which one beat of a heartbeat enters) are extracted. The vehicle state detection unit 117 generates a heartbeat template signal by taking an average of the plurality of extracted signals, and accumulates it in the heartbeat template storage unit 118.

  When the vehicle is traveling, the correlation calculation unit 113A obtains a correlation based on the heart rate template signal already accumulated in the heart rate template accumulation unit 118, thereby obtaining a signal after template matching for the signal from the reception unit for each reception unit. Is calculated. Since noise associated with the running of the vehicle is uncorrelated with the heartbeat signal, it is suppressed by template matching. On the other hand, the heartbeat signal is emphasized by template matching because each beat has a similar waveform. FIG. 20B shows a signal after template matching. Correlation calculation section 113A calculates the correlation value by taking the correlation between the signal after template matching based on the signal from receiving section 102A and the signal after template matching based on the signal from receiving section 102B. Then, the heart rate estimation unit 114 acquires a heart rate based on the correlation value calculated by the correlation calculation unit 113A.

  As the vehicle travels, the posture of the user seated on the vehicle or the body position may change, and the waveform of the heartbeat signal included in the signal from each receiving unit may change. Therefore, the heartbeat acquisition system 100B may perform learning related to the heartbeat template signal (that is, generation and accumulation of the heartbeat template signal) every time the traveling vehicle stops. In this case, the processing unit 110B calculates a heart rate template signal corresponding to the signals received by each of the plurality of receiving units (receiving units 102A and 102B) while the vehicle is stopped by the vehicle state detecting unit 117. The correlation calculation unit 113A uses the heartbeat template signal, the plurality of conversion signals calculated by using the plurality of signals received by the plurality of reception units (reception units 102A and 102B) while the vehicle is traveling, and the time difference setting unit 112A. The correlation value between the plurality of converted signals is calculated based on the time difference set in. This makes it possible to detect (acquire) a heartbeat with higher accuracy.

(Embodiment 4)
Hereinafter, the heartbeat acquisition system 100 shown in the first embodiment is modified to change the travel route of the vehicle in order to detect the heartbeat more accurately according to the physical condition, health state, psychological state, etc. of the user driving the vehicle. A heartbeat acquisition system 100C that performs control such as stopping will be described.

  FIG. 21 is a block diagram showing a configuration of a heartbeat acquisition system 100C according to the present embodiment. As shown in the figure, the heartbeat acquisition system 100C includes a transmission unit 101, reception units 102A and 102B, and a processing unit 110C. The processing unit 110C includes a phase conversion unit 111, a time difference setting unit 112, a correlation calculation unit 113, a heart rate estimation unit 114, an information presentation unit 115, a physical condition state estimation unit 119, and a path control unit 120. In addition, about the structure similar to Embodiment 1 (refer FIG. 1), the code | symbol same as FIG. 1 is attached | subjected in FIG. 21, and description is abbreviate | omitted.

  In the heartbeat acquisition system 100C, the processing unit 110C acquires the heartbeat of the user who drives the vehicle with the heartbeat estimation unit 114, estimates the user's physical condition, health condition, and the like based on the heartbeat, and the vehicle according to the estimation result The vehicle is controlled such as changing the travel route. The processing unit 110 </ b> C is the same as the processing unit 110 described in the first embodiment except for points that are not particularly described here.

(Physical condition estimation unit 119)
The physical condition estimation unit 119 estimates the state (physical condition, health condition, psychological condition, etc.) of the user driving the vehicle from the heart rate estimated (acquired) by the heart rate estimation unit 114. For example, it is known that the heart rate increases or the heart rate interval changes due to tension, stress, or the like. Therefore, the physical condition estimation unit 119 determines information related to the heart rate acquired by the heart rate estimation unit 114 (for example, the presence or absence of a heart rate, the heart rate) based on a predetermined relationship between the physical condition, health condition, psychological state, and the like The state of the user is estimated from the change in the number, the change in the heartbeat interval, and the like. The physical condition estimation unit 119 transmits the estimated user status to the path control unit 120.

(Route control unit 120)
The route control unit 120 performs control such as changing the travel route of the vehicle according to the state of the user transmitted from the physical condition estimation unit 119. For example, when the state of the user estimated and transmitted by the physical condition estimation unit 119 indicates that there is an abnormality in the physical condition or the like, the route control unit 120 controls the vehicle to stop or the travel route of the vehicle Control is made to change the position to move to the shoulder and stop. The route control unit 120 controls the vehicle by, for example, transmitting a control signal generated according to the estimation result of the user state based on the user's heartbeat to the vehicle. This control signal is received in advance so that the vehicle receives the control signal from a device provided in the vehicle and performs predetermined control (for example, changing the travel route to move to the road shoulder, stopping the vehicle, etc.). It is a predetermined signal. FIG. 22 is a diagram illustrating an example of vehicle travel control when the physical condition or the like is estimated to be abnormal according to the user's heartbeat. For example, in a vehicle having a car navigation function or the like, the display content of the display screen for displaying the travel route is estimated from the state shown in FIG. Depending on the control signal to be issued, the state changes to the state shown in FIG. 22 (b). For example, a voice message such as “It seems that the heartbeat is rising. Thus, the vehicle is controlled to stop on the road shoulder.

  Further, when the vehicle is running, a heartbeat signal may be buried due to road noise or a user's body movement, making it difficult to appropriately measure the heartbeat. Therefore, when the physical condition estimation unit 119 estimates that the possibility that there is an abnormality in the user's physical condition or the like is high to some extent, in order to continuously measure the heartbeat with higher accuracy, the path control unit 120 Control for stopping the vehicle or reducing the traveling speed of the vehicle may be performed in order to suppress this. In this case, in order to continuously measure the heartbeat with high accuracy, the route control unit 120 may perform control to change the travel route of the vehicle to a route with less noise based on known route information or the like. .

(Embodiment 5)
In the following, there are many noises associated with vibrations or the like when the vehicle is running, and it may be difficult to extract the heartbeat due to the noises. In order to cope with this case, the heartbeat acquisition system 100 shown in the first embodiment is partially deformed, and noise components are obtained by using reception signals obtained by the receiving unit 102A and the receiving unit 102B that are arranged close to each other. A heartbeat acquisition system 100D that appropriately extracts a heartbeat signal by offsetting the above will be described.

  FIG. 23 is a block diagram showing a configuration of a heartbeat acquisition system 100D according to the present embodiment. As shown in the figure, the heartbeat acquisition system 100D includes a transmission unit 101, reception units 102A and 102B, and a processing unit 110D. The processing unit 110D includes a phase conversion unit 111, a time difference setting unit 112, a signal cancellation unit 121, a heart rate estimation unit 114, and an information presentation unit 115. In addition, about the structure similar to Embodiment 1 (refer FIG. 1), the code | symbol same as FIG. 1 is attached | subjected in FIG. 23, and description is abbreviate | omitted. The processing unit 110D is the same as the processing unit 110 described in the first embodiment, unless otherwise described here.

(Signal canceling unit 121)
The signal canceling unit 121 in the processing unit 110D converts each received signal obtained from the receiving unit 102A and the receiving unit 102B arranged close to each other as illustrated in FIG. Using each converted signal converted in step (1), noise component cancellation processing is performed. For each of the converted signals, as shown in the above-described embodiment, the noise component is adjusted after the difference in heartbeat timing between each part of the human body is adjusted based on the time difference set by the time difference setting unit 112A. Is canceled out. The canceling process will be described with reference to FIG.

  24 (a) and 24 (b) respectively show signals received by the receiving unit 102A and the receiving unit 102B (specifically, the phase is converted by the phase converting unit 111 and the timing is adjusted by the time difference setting unit 112). Signal) over time. In the example of FIGS. 24A and 24B, the first half period is a situation in which the traveling noise is relatively small, for example, when the vehicle is stopped (for example, when the vehicle is not running, including when the engine is stopped or idling). It corresponds to. In the first half period, the heartbeat signal sufficiently appears in each signal from each receiving unit. Note that the heartbeat signal appears larger in the signal from the receiving unit 102B than the signal from the receiving unit 102A. In the example of FIGS. 24A and 24B, the latter half of the period corresponds to a situation in which a relatively large amount of noise is mixed, for example, when the vehicle is traveling. Since the receiving unit 102A and the receiving unit 102B are arranged close to each other, signals having substantially the same period, intensity, and phase are added to both the receiving units as noise. Therefore, in the cancellation process, both signals from the two receiving units are subtracted (that is, the difference between the two signals is calculated). This canceling process suppresses running noise. Note that, as shown in FIGS. 24 (a) and 24 (b), there is a difference in the strength of the heartbeat signal appearing in both signals, so in the signal after cancellation processing as shown in FIG. 24 (c). A part of the heartbeat signal remains.

  Further, the sensitivity of the sensor or the dynamic range at the time of AD conversion may be changed for each receiving unit of the heartbeat acquisition system 100D. For example, it is assumed that the receiving unit 102B has a wider dynamic range and higher resolution than the receiving unit 102A. In this case, a weak heartbeat signal is detected with high sensitivity by the receiving unit 102B, and the receiving unit 102A has a small dynamic range, so it is difficult to enter or is not detected. On the other hand, since the running noise is large, it is detected even in the dynamic range of the receiving unit 102A, and a signal having a period and phase substantially the same as those of the receiving unit 102B is detected. Therefore, the heartbeat signal detected by the receiving unit 102B remains as a residual and is detected by canceling processing such as subtraction of signals from each receiving unit.

(Other embodiments)
As described above, Embodiments 1 to 4 have been described as examples of the technology according to the present disclosure. However, the technology according to the present disclosure is not limited to these embodiments, and can also be applied to embodiments in which changes, replacements, additions, omissions, and the like have been made as appropriate. That is, unless departing from the gist of the present disclosure, various forms conceived by those skilled in the art have been applied to the above-described embodiments, forms constructed by combining components in different embodiments, and the like. Included in one embodiment. For example, the following modifications are also included in one embodiment of the technology according to the present disclosure.

  In the above-described embodiment, the example in which the heartbeat acquisition system mainly includes the reception units 102A and 102B has been described. However, the heartbeat acquisition system may include three or more reception units. Further, the arrangement of the plurality of receiving units is useful as shown in FIG. 2, but is not necessarily limited to this arrangement. For example, the transmission unit and the plurality of reception units may be located in the vicinity of the vehicle regardless of the inside or outside of the vehicle.

  Moreover, in the said embodiment, the time difference setting part 112A in a process part showed the example which calculates a time difference using the several signal received by the several receiving part. The processing unit (time difference setting unit or the like) may calculate the time difference while the vehicle is stopped. In this case, whether or not the vehicle is stopped can be determined by, for example, the vehicle state detection unit 117. In this way, if the time difference calculated while the vehicle is stopped is set, the correlation calculation unit 113A uses the time difference between the signals received at each receiving unit with high accuracy during traveling (or during the subsequent stop). The correlation value can be calculated. Similarly, the processing unit may calculate the above-described time difference when the change in vehicle acceleration exceeds a threshold value. This is based on the fact that the movement of the body of the person who drives the vehicle tends to be stationary during the acceleration / deceleration of the vehicle. In this case, the identification of whether or not the change in the acceleration of the vehicle has exceeded the threshold value can be performed by acquiring information indicating the sensing result of the acceleration from the vehicle.

  In the fourth embodiment, an example in which a heartbeat template signal is generated and accumulated while the vehicle is stopped is shown. However, in the processing unit, when a change in the acceleration of the vehicle exceeds a threshold, a plurality of receiving units A heartbeat template signal may be calculated and stored corresponding to each received signal. In the correlation calculation unit, based on the heartbeat template signal calculated and accumulated during past acceleration / deceleration, the conversion signal obtained from the plurality of reception units, and the time difference set in the time difference setting unit, a plurality of conversion signals It is good also as calculating the correlation value between.

  In the fourth embodiment, the route control unit 120 performs control such as changing the travel route of the vehicle according to the state of the user transmitted from the physical condition estimation unit 119, but according to the heart rate. The vehicle may be controlled. For example, the processing unit 110C (for example, the route control unit 120) controls the vehicle according to a predetermined algorithm or the like according to the heart rate (for example, heart rate, heart rate interval, etc.) acquired by the heart rate estimation unit 114. The signal may be output. That is, the processing unit (for example, the processing unit 110C) in the heartbeat acquisition system acquires the heartbeat based on the correlation value of the signals from the reception unit 102A and the reception unit 102B, and then, the content related to the heartbeat according to the heartbeat. Information (heart rate, heartbeat interval, etc.) may be output, or a signal for controlling the vehicle according to the heartbeat may be output.

  In addition, some or all of the constituent elements constituting each device in the above embodiment may be constituted by one or a plurality of integrated circuits.

  As described above, the heartbeat acquisition system according to the present disclosure is a heartbeat acquisition system (for example, heartbeat acquisition systems 100, 100A, 100B, and 100C) that acquires the heartbeat of the user of the vehicle, and is located on the vehicle and A transmission unit 101 that transmits electromagnetic waves, a plurality of reception units (for example, reception units 102A and 102B) that are located in a vehicle and receive electromagnetic waves reflected by a user, and a plurality of electromagnetic waves received by the plurality of reception units. And a processing unit (for example, processing units 110, 110A, 110B, and 110C) that acquires a user's heartbeat using the signal, and the processing unit outputs each of the plurality of electromagnetic wave signals according to the phase of the signal. Is converted into a converted signal, a correlation value between a plurality of converted signals as a conversion result is calculated, and the user's heartbeat is obtained using the correlation value, Carry out an output corresponding to the beat. Thereby, it may be possible to acquire a heartbeat with high accuracy.

  Further, for example, the processing unit (for example, the processing units 110, 110A, 110B, and 110C) may perform conversion signal calculation by performing conversion so that the phase angle of the electromagnetic wave signal is zero.

  Moreover, the transmission part 101 and several receiving part (for example, receiving part 102A, 102B) are good also as being located under the seat surface on which a user sits in a vehicle.

  The plurality of receiving units are spaced apart from each other and arranged below the thighs of the user seated in the vehicle, and the correlation calculation units 113 and 113A in the processing unit set the correlation values to the arrangement of the plurality of receiving units. It is good also as calculating based on the time difference (For example, the time difference set to the time difference setting parts 112 and 112A) relevant to.

  The plurality of receiving units include a receiving unit 102A (first receiving unit) disposed below the first part of the thigh of one leg of the user seated in the vehicle, and the first part of the thigh. The receiving unit 102B (second receiving unit) disposed below the second part closer to the knee, and the receiving unit 102C disposed below the part between the first part and the second part of the thigh. Where the first distance between the first receiver and the second receiver is greater than the second distance between the first receiver and the third receiver, and the process The unit 110 obtains a first correlation value that is a correlation value between a first converted signal obtained by converting the signal received by the first receiving unit and a second converted signal obtained by converting the signal received by the second receiving unit. , The first converted signal, the second converted signal, and the time difference set by the time difference setting unit 112 corresponding to the first distance (first A second correlation value, which is a correlation value between the first converted signal and the third converted signal obtained by converting the signal received by the third receiving unit, with the first converted signal , Calculated based on the third converted signal and the time difference (second time difference) set by the time difference setting unit 112 corresponding to the second distance shorter than the first time difference, and the heart rate of the user is calculated using the correlation value ( It is good also as acquiring using a 1st correlation value and a 2nd correlation value.

  The plurality of receiving units include a receiving unit 102A (first receiving unit) and a receiving unit 102B (second receiving unit) located in front of the vehicle from the first receiving unit. A correlation value between the first converted signal obtained by converting the signal received by the receiving unit and the second converted signal obtained by converting the signal received by the second receiving unit is represented by the first converted signal and the second converted signal, It is good also as calculating based on the time difference set by the time difference setting part 112 regarding the distance between a 1st receiving part and a 2nd receiving part, and acquiring a user's heartbeat using a correlation value.

  Further, the processing unit (for example, the processing units 110A and 110B) may calculate the time difference by the time difference setting unit 112A using a plurality of signals received by the plurality of receiving units while the vehicle is stopped.

  Moreover, a process part (for example, process part 110A, 110B) is good also as calculating a time difference using the several signal received by the several receiving part, when the change of the acceleration of a vehicle exceeds a threshold value.

  In addition, the processing unit 110B calculates a heartbeat template signal corresponding to signals received by each of the plurality of receiving units while the vehicle is stopped, and is received by the plurality of receiving units while the vehicle is traveling. The correlation values between the plurality of converted signals may be calculated based on the plurality of converted signals calculated using the plurality of signals and the time difference set in the time difference setting unit 112A or the like.

  In addition, the processing unit (for example, the processing units 110A and 110B) calculates a heartbeat template signal corresponding to the signals received by each of the plurality of receiving units when the change in the acceleration of the vehicle exceeds the threshold, and the heartbeat template signal Based on the plurality of converted signals and the time difference set in the time difference setting unit 112A or the like, a correlation value between the plurality of converted signals may be calculated.

  The plurality of receiving units (for example, the receiving units 102A and 102B) may be disposed below the thighs of the legs far from the accelerator pedal provided in the vehicle among the legs of the user seated in the vehicle. Good.

  The output from the processing unit 110C may include transmitting a control signal generated according to the user's heartbeat to the vehicle.

  Further, the output by the processing unit (for example, the processing units 110, 110A, 110B, etc.) may include presenting information generated according to the user's heartbeat to the user.

  The transmission unit 101 may transmit microwaves, and a plurality of reception units (for example, the reception units 102A and 102B) may receive microwaves.

  Further, as one aspect of the present disclosure, for example, a heartbeat acquisition method including all or part of the processing procedure illustrated in FIG. 9 may be used. For example, the heartbeat acquisition method is a heartbeat acquisition method for acquiring the heartbeat of the user of the vehicle, and (a) transmits electromagnetic waves to the user in the vehicle, and (b) transmits the electromagnetic waves reflected by the user to a plurality of receiving devices ( For example, for each of the electromagnetic wave signals received by the receiving units 102A and 102B) and received by a plurality of receiving devices, a converted signal obtained by converting the signal according to the phase of the signal is calculated, and (d ) Calculate a correlation value between the plurality of calculated conversion signals, and (e) obtain the user's heartbeat using the correlation value. Further, as one aspect according to the present disclosure, a program (computer program) that realizes the processing according to the heartbeat acquisition method by a computer may be used, or a digital signal that includes the program may be used. Further, as one aspect according to the present disclosure, a recording medium that can read the program or the digital signal by a computer, for example, a flexible disk, a hard disk, a CD-ROM, an MO, a DVD, a DVD-ROM, a DVD-RAM, a BD (Blu-ray (registered trademark) Disc), recorded on a semiconductor memory, or the like. The digital signal may be recorded on these recording media. Further, as one aspect according to the present disclosure, the program or the digital signal may be transmitted via an electric communication line, a wireless or wired communication line, a network represented by the Internet, a data broadcast, or the like. Further, as one aspect according to the present disclosure, a computer system including a microprocessor and a memory may be used, the memory storing the program, and the microprocessor operating according to the program. In addition, the program or the digital signal is recorded on the recording medium and transferred, or the program or the digital signal is transferred via the network or the like and executed by another independent computer system. You may do that.

  Forms realized by arbitrarily combining the constituent elements and functions shown in the embodiment and the modified examples are also included in the scope of the present disclosure.

  The embodiments in the present disclosure should be considered as illustrative in all points and not restrictive. The scope of the technology according to the present disclosure is shown not by the above embodiment but by the scope of claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

  The heartbeat acquisition system and the like according to the present disclosure can be used for measuring the heartbeat of a user who uses the vehicle.

DESCRIPTION OF SYMBOLS 10 Seat 11 Backrest part 12, 12a Seat part 13 Human body surface 21 Accelerator pedal 22 Brake pedal 23 Handle (steering wheel)
100, 100A, 100B, 100C, 100D Heartbeat acquisition system 101 Transmission unit 102A, 102B, 102C Reception unit 110, 110A, 110B, 110C, 110D Processing unit 111 Phase conversion unit 112, 112A Time difference setting unit 113, 113A Correlation calculation unit 114 Heartbeat estimation section 115 Information presentation section 116 Feature point calculation section 117 Vehicle state detection section 118 Heartbeat template storage section 119 Physical condition estimation section 120 Path control section 121 Signal cancellation section

Claims (16)

A heart rate acquisition system for acquiring a heart rate of a user of a vehicle,
A transmitter located in the vehicle and transmitting electromagnetic waves to the user;
A plurality of receiving units located in the vehicle and receiving electromagnetic waves reflected by the user;
Using a plurality of electromagnetic wave signals received by the plurality of receiving units, a processing unit for acquiring the user's heartbeat,
The processor is
(A) converting the signals of the plurality of electromagnetic waves into a plurality of converted signals using phases of the signals of the plurality of electromagnetic waves,
(B) calculating a correlation value between the plurality of converted signals;
(C) using the correlation value to obtain a heartbeat of the user;
(D) A heartbeat acquisition system that performs output according to the heartbeat of the user. The heartbeat acquisition system according to claim 1, wherein the processing unit performs the conversion by calculating so that a phase angle of each signal of the electromagnetic wave is zero in (a). The heart rate acquisition system according to claim 1, wherein the transmission unit and the plurality of reception units are positioned below a seating surface on which a user is seated in the vehicle. The plurality of receiving units are spaced apart from each other and arranged below the thighs of a user seated in the vehicle,
The heart rate acquisition system according to any one of claims 1 to 3, wherein the processing unit calculates the correlation value based on a time difference related to the arrangement of the plurality of receiving units in (b). The plurality of receiving units are arranged below the first part of the thigh of one leg of the user who sits in the vehicle, and the knee from the first part of the thigh. A second receiver disposed below a second portion close to the second portion, and a third receiver disposed below a portion between the first portion and the second portion of the thigh,
A first distance between the first receiver and the second receiver is greater than a second distance between the first receiver and the third receiver;
In (b), the processing unit is between the first converted signal obtained by converting the signal received by the first receiving unit and the second converted signal obtained by converting the signal received by the second receiving unit. A first correlation value that is a correlation value is calculated based on the first converted signal, the second converted signal, and a first time difference corresponding to the first distance, and the first converted signal and the first The second correlation value, which is a correlation value between the third converted signal obtained by converting the signal received by the three receiving units, is shorter than the first converted signal, the third converted signal, and the first time difference. 5. The calculation is performed based on a second time difference corresponding to the second distance, and the heart rate of the user is acquired using the first correlation value and the second correlation value in (c). Heart rate acquisition system. The plurality of receiving units include a first receiving unit and a second receiving unit located in front of the vehicle from the first receiving unit,
In (b), the processing unit is between the first converted signal obtained by converting the signal received by the first receiving unit and the second converted signal obtained by converting the signal received by the second receiving unit. A correlation value is calculated based on a time difference related to the distance between the first converted signal, the second converted signal, and the first receiving unit and the second receiving unit, and the heart rate of the user is calculated as the correlation value The heartbeat acquisition system according to claim 3, wherein the heartbeat acquisition system is acquired by using. In the processing unit (b),
The heart rate acquisition system according to any one of claims 4 to 6, wherein the time difference is calculated using a plurality of signals received by the plurality of receiving units while the vehicle is stopped. In the processing unit (b),
The heart rate acquisition system according to any one of claims 4 to 6, wherein when the change in acceleration of the vehicle exceeds a threshold, the time difference is calculated using a plurality of signals received by the plurality of receiving units. In the processing unit (b),
Calculating a heartbeat template signal corresponding to the signal received by each of the plurality of receiving units while the vehicle is stopped;
Based on the heartbeat template signal, the plurality of conversion signals calculated using the plurality of signals received by the plurality of reception units during the traveling of the vehicle, and the plurality of conversion signals, The heart rate acquisition system according to any one of claims 4 to 6, wherein the correlation value is calculated. In the processing unit (b),
When a change in acceleration of the vehicle exceeds a threshold value, a heart rate template signal is calculated corresponding to the signal received by each of the plurality of receiving units,
The heartbeat acquisition system according to any one of claims 4 to 6, wherein the correlation value between the plurality of converted signals is calculated based on the heartbeat template signal, the plurality of converted signals, and the time difference. The plurality of receiving units are arranged below a thigh of a leg farther from an accelerator pedal included in the vehicle among the legs of a user seated in the vehicle. Heart rate acquisition system as described in. The heartbeat acquisition system according to any one of claims 1 to 11, wherein the output in (d) by the processing unit includes transmitting a control signal generated according to a heartbeat of the user to the vehicle. The heartbeat acquisition system according to any one of claims 1 to 12, wherein the output in (d) by the processing unit includes presenting information generated according to a heartbeat of the user to the user. The transmitter transmits a microwave;
The heart rate acquisition system according to any one of claims 1 to 13, wherein the plurality of reception units receive microwaves. In the processing unit (c),
The heartbeat acquisition system according to any one of claims 1 to 14, wherein the heartbeat is acquired by extracting a peak from time-series data of the correlation value. A heart rate acquisition method for acquiring a heart rate of a user of a vehicle,
(A) transmitting electromagnetic waves to the user in the vehicle;
(B) receiving electromagnetic waves reflected by the user using a plurality of receiving devices;
(C) converting a plurality of electromagnetic wave signals received by the plurality of receiving devices into a plurality of converted signals using phases of the respective electromagnetic wave signals;
(D) calculating a correlation value between the plurality of converted signals;
(E) A heartbeat acquisition method for acquiring a heartbeat of the user using the correlation value.

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