Estimation device and estimation method

Abstract

An estimation device (10A) includes: transmission / reception units (30A, etc.) that have a transmission antenna element and a reception unit and that are located in a periphery of a predetermined range containing a first living organism; memory (41) storing teaching signals that are an M×N count of second reception signals obtained by causing reception units to receive, in advance, second reception signals including reflected signals that are second transmitted signals transmitted as to a second living organism from transmission antenna elements and reflected by the second living organism; a first vector calculating unit that calculates a teaching first vector and a test first vector for each of the teaching signals and an M×N count of first reception signals obtained by each of the reception units receiving the first reception signals; and a circuit (40) including an estimating unit that calculates a plurality of features from the teaching first vector and the test first vector and uses the plurality of features that are calculated to estimate identification information regarding the first living organism by a predetermined method.

Description

[Technical field]

[0001] The present disclosure relates to an estimation device and an estimation method. [Background technology]

[0002] There is known a technique for irradiating a living body with a wireless signal and receiving the reflected signal to identify or estimate the living body or its orientation (eg, Patent Documents 1 and 2).

[0003] Patent Document 1 discloses a device that estimates the identity of an individual driver by irradiating the driver with electromagnetic waves and extracting heart rate and heart sound signals using the reflected waves.

[0004] Patent Document 2 discloses a method for measuring the heart rate of a vehicle driver using a plurality of transceivers.

[0005] Patent Document 3 discloses a device for measuring a 360-degree radiation pattern of a subject using multiple antennas.

[0006] Patent Document 4 discloses an identification device that performs personal identification by placing multiple antennas in the vicinity of a subject.

[0007] Patent Document 5 discloses an estimation device that estimates the orientation of a living body by placing multiple antennas in the vicinity of a subject.

[0008] Patent Document 6 discloses a technique for irradiating a living body with a wireless signal and receiving the reflected signal to estimate the orientation of the living body. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2015-042293 A [Patent Document 2] JP 2009-055997 A [Patent Document 3] JP 2007-325621 A [Patent Document 4] JP 2019-93104 A [Patent Document 5] JP 2019-211458 A [Patent Document 6] Patent No. 6504546 Summary of the Invention [Problem to be solved by the invention]

[0010] Incidentally, in biometric identification or biometric orientation estimation using electromagnetic waves, as disclosed in Patent Document 1, Patent Document 2, Patent Document 4, or Patent Document 5, biometric identification is often performed when the subject and the antenna are relatively close to each other.

[0011] However, when identifying an individual in a small space such as a driver's seat or a private room, the constraint of a short distance between the subject and the antenna is unlikely to be a problem, but there is a problem that it is difficult to use in situations such as everyday life.

[0012] Furthermore, the method of Patent Document 6 can estimate the direction or position of a person even in areas other than a small one, but cannot identify living bodies.

[0013] The present disclosure has been made in consideration of the above-mentioned circumstances, and aims to provide an estimation device and an estimation method that can identify a living organism using electromagnetic waves even when the subject is distant from the antenna. [Means for solving the problem]

[0014] In order to achieve the above object, an estimation device according to one embodiment of the present disclosure includes M (M is an integer of 1 or more) transmitting antenna elements arranged around a predetermined range including a first living body, the M transmitting antenna elements transmitting first transmitting signals to the predetermined range, and N (N is an integer of 3 or more) receiving units arranged around the predetermined range, each having a receiving antenna element, the N receiving units receiving, for a predetermined period of time, a first receiving signal including a reflected signal resulting from reflection of the first transmitting signal by the first living body using the receiving antenna elements, and detecting a second transmitting signal transmitted from the M transmitting antenna elements to a second living body, the second transmitting signal being reflected by the second living body. the N receiving units receive in advance a second received signal including a reflected signal reflected by a target object; a first vector calculation unit that calculates a teacher first vector and a test first vector for the teacher signal and the M×N first received signals obtained by each of the N receiving units receiving the first received signal; and an estimation unit that calculates a plurality of feature amounts from the teacher first vector and the test first vector and estimates identification information for the first living body by a predetermined method using the calculated plurality of feature amounts.

[0015] Furthermore, these general or specific aspects may be realized by a system, a method, an integrated circuit, a computer program, or a recording medium such as a computer-readable CD-ROM, or may be realized by any combination of the system, the method, the integrated circuit, the computer program, and the recording medium. Effect of the Invention

[0016] According to the estimation device of the present disclosure, it is possible to identify a living body using electromagnetic waves even when the subject is far away from the antenna. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a configuration diagram showing an example of the configuration of an estimation device according to the first embodiment. [Diagram 2]FIG. 2 is a diagram illustrating an example of the teacher signal illustrated in FIG. [Diagram 3] FIG. 3 is a configuration diagram showing an example of a detailed configuration of a circuit according to the first embodiment. [Figure 4] FIG. 4 is a flowchart showing an example of the operation of the estimation device according to the first embodiment. [Diagram 5] FIG. 5 is a flowchart showing a first example of detailed operation of the estimation device according to the first embodiment. [Figure 6] FIG. 6 is a flowchart showing a second example of the detailed operation of the estimation device according to the first embodiment. [Figure 7] FIG. 7 is a diagram showing an environment used for a test by the estimation device in the first embodiment. [Figure 8] FIG. 8 is a configuration diagram showing an example of a detailed configuration of a circuit according to the second embodiment. [Figure 9] FIG. 9 is a diagram showing an example of an arrangement of antenna elements according to the second embodiment. [Figure 10] FIG. 10 is a diagram showing an example of an arrangement of antenna elements according to the second embodiment. [Figure 11] FIG. 11 is a flowchart showing an example of the operation of the estimation device according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] (Findings on which this disclosure is based) Patent Documents 1 and 2 disclose a device that irradiates electromagnetic waves to a person sitting in the driver's seat of a car and measures the reflected waves from the person. The device measures the heart rate or heart sound by performing arithmetic processing on the measurement results, and realizes biometric identification by obtaining the time correlation of the measured heart rate or heart sound. However, as described above, the method of Patent Document 1 can only be operated in a limited environment where the positions of the subject and the antenna can be identified in a narrow space such as a driver's seat, in other words, there is a problem that it cannot be operated in any other environment.

[0019] In indoor situations such as everyday life, it is necessary to perform biological identification in an environment where the antenna and the subject are separated by a certain distance and the positional relationship between the antenna and the subject is given some degree of freedom.

[0020] As a result of extensive research into this issue, the inventors discovered the following in order to identify a living body using electromagnetic waves even when the subject is far from the antenna, such as indoors.

[0021] That is, antenna elements are installed around the room in which the object to be identified is active, and transmitted waves are sent from various directions, and reflected or scattered waves are received in various directions to obtain a received signal that captures as many characteristics of the living body as possible. Since the received signal varies depending on the distance between the living body and the antenna, or the orientation or posture of the living body, in no small way, in order to identify the living body, a teacher signal is obtained while estimating the position or posture of the living body from the received signal, and the position or posture of the living body is stored as an identification position.

[0022] In this case, if the distance between the antenna and the subject is sufficiently close, as in the prior art, the amplitude of the received signal is relatively large, making it possible to identify the individual. However, if biometric identification is performed using electromagnetic waves when the subject is far from the antenna, such as indoors, the amplitude of the received signal becomes smaller due to attenuation over distance, making it difficult to distinguish from the noise floor, and the accuracy of identification decreases.

[0023] Therefore, we found that by calculating the frequency response matrix of the received signal, extracting the frequency components that fluctuate due to biological activity, calculating the correlation matrix of the extracted frequency components and performing eigenvalue decomposition, and using the eigenvectors as features to calculate the degree of similarity with the teacher signal, it is possible to accurately identify the target living organism in an area such as a living space.

[0024] More specifically, in order to achieve the above object, an estimation device according to one embodiment of the present disclosure includes M (M is an integer of 1 or more) transmitting antenna elements arranged around a predetermined range including a first living body, the M transmitting antenna elements transmitting a first transmitting signal to the predetermined range, and N (N is an integer of 3 or more) receiving units arranged around the predetermined range, each having a receiving antenna element, the N receiving units receiving, for a predetermined period of time, a first receiving signal including a reflected signal obtained by reflecting the first transmitting signal by the first living body using the receiving antenna elements, and a second transmitting signal transmitted from the M transmitting antenna elements to a second living body being reflected by the second receiving antenna elements. The estimation device includes a memory that stores a teacher signal, which is M×N second received signals obtained by previously having the N receiving units receive a second received signal including a reflected signal reflected by a living organism, a first vector calculation unit that calculates a teacher first vector and a test first vector for the teacher signal and the M×N first received signals obtained by each of the N receiving units receiving the first received signal, and an estimation unit that calculates a plurality of feature amounts from the teacher first vector and test first vector, and estimates identification information about the first living organism using a predetermined method using the calculated plurality of feature amounts.

[0025] According to this, the estimation device calculates a plurality of feature quantities using a teacher first vector and a test first vector obtained from a first reception signal and a teacher signal. Here, the plurality of feature quantities are calculated, for example, by using the sum of the inner products of the first vectors or machine learning using a k-nearest neighbor method. Then, depending on whether the maximum feature quantity among the plurality of feature quantities exceeds a threshold value, it is determined whether the first living body and the second living body used to acquire the teacher signal are the same, thereby estimating identification information about the living body. In this way, the estimation device uses the teacher first vector and the test first vector to calculate the plurality of feature quantities, in other words, does not use the time waveforms of the first reception signal and the teacher signal. If the time waveforms of the first reception signal and the teacher signal were used to calculate the plurality of feature quantities, problems such as deterioration of the S / N ratio of the components derived from the living body or an increase in processing load and power consumption due to a large amount of processing required for the sliding correlation calculation of the time waveform may occur. Since the estimation device calculates the plurality of feature quantities using the teacher first vector and the test first vector, it is possible to suppress the occurrence of problems such as the deterioration of the S / N ratio and the increase in processing load and power consumption. Therefore, the estimation device can perform biometric identification using electromagnetic waves even when the subject is located far away from the antenna.

[0026] For example, the first vector calculation unit may calculate the teacher first vector by calculating a teacher second matrix from the teacher signal and decomposing rearranged elements of the calculated teacher second matrix, and may calculate the test first vector by calculating a received second matrix from the first received signal and decomposing the rearranged elements of the calculated received second matrix.

[0027] According to this, the first vector calculation unit easily calculates the first vector by decomposing the rearranged elements of the calculated second matrix for each of the teacher signal and the first received signal, thereby estimating the identification information for the living body. Therefore, the estimation device can more easily perform living body identification using electromagnetic waves even when the subject is distant from the antenna.

[0028] For example, when calculating the teacher first vector, the first vector calculation unit may calculate the teacher first vector having as its components a sequence in which a plurality of eigenvalues ​​obtained by eigenvalue decomposition of the rearranged elements of the teacher second matrix are arranged in order from largest to smallest, and when calculating the test first vector, the first vector calculation unit may calculate the test first vector having as its components a sequence in which a plurality of eigenvalues ​​obtained by eigenvalue decomposition of the rearranged elements of the received second matrix are arranged in order from largest to smallest.

[0029] According to this, the first vector calculation unit easily calculates the first vector by eigenvalue decomposition of the rearranged elements of the second matrix, thereby estimating the identification information of the living body. Therefore, the estimation device can more easily perform living body identification using electromagnetic waves even when the subject is distant from the antenna.

[0030] For example, when calculating the teacher first vector, the first vector calculation unit may calculate the teacher first vector having as its components a sequence in which a plurality of singular values ​​obtained by singular value decomposition of the rearranged elements of the teacher second matrix are arranged in order from largest to smallest, and when calculating the test first vector, the first vector calculation unit may calculate the test first vector having as its components a sequence in which a plurality of singular values ​​obtained by singular value decomposition of the rearranged elements of the received second matrix are arranged in order from largest to smallest.

[0031] According to this, the first vector calculation unit easily calculates the first vector by singular value decomposition of the rearranged elements of the second matrix, thereby estimating the identification information of the living body. Therefore, the estimation device can more easily perform living body identification using electromagnetic waves even when the subject is distant from the antenna.

[0032] For example, the estimation unit may identify the organism by taking the sum of a predetermined number of feature amounts from among the plurality of feature amounts.

[0033] According to this, the estimation unit identifies the first living body using the sum of a predetermined number of features among the multiple features. At this time, the larger the sum of the features, the higher the probability that the first living body and the second living body are identical. Using this, the identification information can be estimated based on the identity of the first living body and the second living body. Therefore, the estimation device can more easily perform living body identification using electromagnetic waves even when the subject is far away from the antenna.

[0034] For example, at least one of the N transmitting antenna elements and the M receiving antenna elements may form an array antenna whose directivity in the vertical direction is controllable.

[0035] According to this, by using an array antenna with controllable vertical directivity, it is possible to grasp the characteristics of a living body that is long in the vertical direction, which contributes to the estimation of appropriate identification information. Therefore, the estimation device can more appropriately perform biological identification using electromagnetic waves even when the subject is far away from the antenna.

[0036] For example, at least one of the N transmitting antenna elements and the M receiving antenna elements may constitute an array antenna whose horizontal directivity is controllable, and the estimation device may further include a position estimation unit that estimates the position of the first living body based on the first received signal and determines whether the position of the first living body is within a specified area.

[0037] According to this, by using an array antenna whose horizontal directivity is controllable, the horizontal position of the living body can be further estimated. Therefore, the estimation device can estimate the living body position and identify the living body by using electromagnetic waves even when the subject is far from the antenna.

[0038] An estimation method according to one aspect of the present disclosure is an estimation method executed by an estimation device, the estimation device including: M (M is an integer of 1 or more) transmitting antenna elements arranged around a predetermined range including a first living body; N (N is an integer of 3 or more) receiving units each having a receiving antenna element and arranged around the predetermined range; and a memory storing teacher signals that are M×N second received signals obtained by causing the N receiving units to receive in advance second received signals including reflected signals reflected by the second living body, the second transmitted signals being transmitted from the M transmitting antenna elements to a second living body; The estimation method includes: an antenna element transmitting a first transmission signal within the specified range; the N receiving units receiving, for a specified period of time, a first received signal including a reflected signal of the first transmission signal reflected by the first living organism using the receiving antenna element; calculating a teacher first vector and a test first vector for each of the teacher signal and the M×N first received signals obtained by each of the N receiving units receiving the first received signal; calculating a plurality of feature amounts from the teacher first vector and test first vector; and estimating identification information for the first living organism using a specified method using the calculated plurality of feature amounts.

[0039] This provides the same effects as the above-mentioned estimation device.

[0040] Furthermore, these general or specific aspects may be realized by a system, a method, an integrated circuit, a computer program, or a recording medium such as a computer-readable CD-ROM, or may be realized by any combination of the system, the method, the integrated circuit, the computer program, and the recording medium.

[0041] Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the embodiments described below all show preferred specific examples of the present disclosure. The numerical values, shapes, materials, components, arrangement and connection forms of the components, steps, and order of steps shown in the following embodiments are merely examples and are not intended to limit the present disclosure. In addition, among the components in the following embodiments, components that are not described in the independent claims showing the highest concept of the present disclosure will be described as any components constituting a more preferred embodiment. Note that in this specification and the drawings, components having substantially the same functional configuration will be given the same reference numerals to omit repeated explanations.

[0042] (Embodiment 1) In this embodiment, an estimation device that can identify a living body using electromagnetic waves even when the subject is placed far away from the antenna will be described.

[0043] [Configuration of Estimation Device 10A] Fig. 1 is a configuration diagram showing an example of the configuration of an estimation device 10A in this embodiment. Fig. 2 is a diagram showing an example of a teacher signal 42 shown in Fig. 1. Fig. 3 is a configuration diagram showing an example of a detailed configuration of a circuit 40 shown in Fig. 1.

[0044] The estimation device 10A shown in FIG. 1 is a device that estimates identification information about a living body, in other words, a device that identifies a living body and generates identification information indicating the identification result.

[0045] The estimation device 10A includes M (M is an integer of 1 or more) transmitting antenna elements, N (N is an integer of 3 or more) receiving units each having a receiving antenna element, a circuit 40, and a memory 41.

[0046] The M transmitting antenna elements transmit transmission signals to a predetermined range A1 including the living body 50. The transmission signals are high-frequency signals such as microwaves generated by a transmitter or the like. The living body 50 is, for example, a human being, and this case will be described as an example, but is not limited to this. The living body 50 is an estimation target of the estimation device 10A and is a living body (also called a first living body) that is to be identified. The predetermined range A1 is a space of a predetermined range that includes the living body 50. In other words, the predetermined range A1 is a space used by the estimation device 10A to estimate the living body 50.

[0047] Identification of a living body includes identification of an individual living body (i.e., an individual) or identification of the orientation of the living body. The orientation of a living body represents the direction in which the living body is facing, in other words, the direction in which the front of the living body faces, and is expressed by a direction such as north, south, east, or west, or by the direction of a transmitting antenna element or a receiving antenna.

[0048] For example, the M transmitting antenna elements transmit a first transmission signal to a predetermined range A1 including a living body 50 as an identification target. Furthermore, the M transmitting antenna elements transmit a second transmission signal to a predetermined range A1 including a known living body 50 (also called a second living body) in order to acquire a teacher signal. The transmitted first transmission signal or second transmission signal is reflected by the living body 50.

[0049] Each of the N receiving units has a receiving antenna element and is arranged around the predetermined range A1. Each of the N receiving units receives a receiving signal including a reflected signal of a transmission signal reflected by the living body 50 for a predetermined period using the receiving antenna element. For example, each of the N receiving units receives a first receiving signal including a reflected signal of a first transmission signal reflected by a first living body for a predetermined period using the receiving antenna element. Also, for example, each of the N receiving units receives a teacher signal, which is a second receiving signal including a reflected signal of a second transmission signal reflected by a second living body, for a period K times the predetermined period (K is 2 or more).

[0050] In this embodiment, as shown in Fig. 1, the estimation device 10A includes, for example, eight transceiver units 30A to 30H, a circuit 40, and a memory 41. That is, the M transmitting antenna elements and the N receiving units may be configured with eight transceiver units 30A, 30B, 30C, 30D, 30E, 30F, 30G, and 30H (also referred to as 30A to 30H). The number of transceivers is not limited to eight.

[0051] If the antenna elements included in the transmitting and receiving unit form an array antenna whose directivity is controllable in a direction perpendicular to the floor surface, which is a horizontal plane (i.e., vertical direction), it can provide an effect of improving the accuracy of identifying the living body 50. In other words, if at least one of the N transmitting antenna elements and the M receiving antenna elements forms an array antenna whose directivity is controllable in the vertical direction, it can provide an effect of improving the accuracy of identifying the living body 50.

[0052] This is because a living body 50 in an upright or sitting position is generally longer in the vertical direction than in the horizontal direction, and it is believed that when the living body 50 reflects or scatters radio waves, more features appear in the vertical direction.

[0053] In addition, since the horizontal characteristics of the living body 50 when it reflects or scatters radio waves also depend on the position of the living body 50, it is possible to achieve the effect of increasing robustness by using the vertical characteristics obtained by an array antenna whose vertical directivity can be controlled.

[0054] [Transmitter / receiver 30A~30H] In this embodiment, the eight transmitting / receiving units 30A-30H are arranged at positions around the predetermined range A1, and transmit transmission signals to the predetermined range A1 to receive reception signals including reflected signals reflected by the living body 50. For example, the eight transmitting / receiving units 30A-30H may be arranged in a circle at equal intervals, or may be arranged at positions outside the predetermined range A1.

[0055] 1, each of the transceivers 30A to 30H has one antenna element. Specifically, the transceiver 30A has an antenna element 31A, and the transceiver 30B has an antenna element 31B. The same is true for the other transceivers 30C to 30H.

[0056] The transmitting / receiving units 30A to 30H transmit a transmission signal to the predetermined range A1 using the antenna elements 31A to 31H. More specifically, the transmitting / receiving units 30A to 30H emit microwaves as a transmission signal to the living body 50 using the antenna elements 31A to 31H. The transmitting / receiving units 30A to 30H may transmit an unmodulated transmission signal or a modulated transmission signal using the antenna elements 31A to 31H. When transmitting a modulated transmission signal, the transmitting / receiving units 30A to 30H may further include a circuit for performing the modulation process.

[0057] Further, the transmitting / receiving units 30A to 30H receive, for a predetermined period of time, reception signals including reflected signals that are transmission signals reflected by the living body 50, using the antenna elements 31A to 31H. The transmitting / receiving units 30A to 30H output the received reception signals to the circuit 40. Each of the transmitting / receiving units 30A to 30H may include a circuit for processing the reception signals. In this case, each of the transmitting / receiving units 30A to 30H may convert the received reception signals into low-frequency signals by frequency conversion processing. Each of the transmitting / receiving units 30A to 30H may also perform demodulation processing on the reception signals. Then, each of the transmitting / receiving units 30A to 30H outputs a first reception signal obtained by frequency conversion processing and / or demodulation processing to the circuit 40.

[0058] In the example shown in Fig. 1, the transmitting section and the receiving section are expressed as being composed of eight transceiver units 30A-30H each having four antenna elements common to both transmitting and receiving, but this is not limited to the above. The eight transceiver units 30A-30H are not limited to eight, and may be composed of N transceiver units (N is an integer of 3 or more). Also, a transmitting section having M transmitting antenna elements (M is an integer of 1 or more) and a receiving section having N receiving antenna elements may be provided separately.

[0059] [Memory 41] The memory 41 is an auxiliary storage device having a non-volatile storage area, and is, for example, a read only memory (ROM), a flash memory, a hard disk drive (HDD), etc. The memory 41 stores, for example, information used in various processes for operating the estimation device 10A.

[0060] The memory 41 stores a teacher signal 42 as shown in Fig. 1. The teacher signal 42 is a signal waveform previously acquired for a second living body that is a known living body 50 located in a predetermined range A1. More specifically, the teacher signal 42 is M x N second received signals obtained by having N receiving units receive in advance second received signals including reflected signals obtained by transmitting second transmitted signals from M transmitting antenna elements to the second living body and reflecting the second living body. Here, the teacher signal 42 may be M x N second received signals obtained by having N receiving units receive in advance the second received signals for a period K times the predetermined period (K is 2 or more).

[0061] In this embodiment, the M transmitting antenna elements and the N receiving units are configured by eight transmitting / receiving units 30A to 30H as shown in Fig. 1. An example of the teacher signal 42 in this case will be described with reference to Fig. 2. The teacher signal 42 shown in Fig. 2 is an example of a received signal received by one receiving unit during a measurement period.

[0062] The teacher signal 42 shown in Figure 2 is a time response waveform of multiple received signals obtained by the transceiver units 30A to 30H receiving in advance received signals including reflected signals that are the result of the transmission signals transmitted from the antenna elements 31A to 31H to a known living body 50 (second living body) located in a predetermined range A1 and that are reflected by the surface of the living body 50.

[0063] That is, the teacher signal 42 shown in Fig. 2 is a plurality of received signals obtained by the transmitting / receiving units 30A to 30H receiving received signals including reflected signals in advance during a measurement period. Here, the measurement period is a period that is K times (K is 1 or more) the above-mentioned predetermined period. The measurement period is, for example, 120 seconds, but is not limited to this. The measurement period may be any period that is equal to or longer than the human heartbeat period, and may be 3 seconds, 10 seconds, or 30 seconds.

[0064] The teacher signal 42 may be acquired in advance for each of the plurality of known second living bodies. In this case, the memory 41 may store the plurality of teacher signals 42 corresponding to the plurality of known second living bodies, respectively, in a state in which the teacher signals 42 are associated with estimation information for estimating the corresponding second living body.

[0065] Furthermore, the memory 41 may store a plurality of teacher signals 42 corresponding to the same second living body.

[0066] Furthermore, the teacher signal 42 may be acquired in advance for each of a plurality of postures (standing, sitting, lying, etc.) of the same second living body, and may be acquired in advance for each direction in which the second living body faces. In this case, the memory 41 may store the teacher signal 42 in a state in which it is associated with posture or direction information of the second living body.

[0067] [Circuit 40] The circuit 40 executes various processes to operate the estimation device 10A. The circuit 40 is configured, for example, with a processor (for example, a CPU (Central Processing Unit)) that executes a control program, and a volatile storage area (main storage device) that is used as a work area when the control program is executed. This storage area is, for example, a RAM (Random Access Memory).

[0068] The circuit 40 temporarily stores the first received signal acquired from each of the N receiving units in a storage area for a predetermined period of time. The circuit 40 may temporarily store the phase and amplitude of the first received signal in the storage area for a predetermined period of time. In this embodiment, the circuit 40 temporarily stores the received signals acquired from each of the transmitting / receiving units 30A to 30H in a storage area for a predetermined period of time.

[0069] The circuit 40 may be configured with a dedicated circuit for performing various processes to operate the estimation device 10A. That is, the circuit 40 may be a circuit that performs software processing, or a circuit that performs hardware processing. The circuit 40 may also have a non-volatile storage area.

[0070] Next, the functional configuration of the circuit 40 will be described.

[0071] As shown in FIG. 3, the circuit 40 includes a first vector calculation unit 410 and an estimation unit 412.

[0072] <First Vector Calculation Unit 410> More specifically, first, the first vector calculation unit 410 calculates each propagation channel matrix H(t) using the received signal stored in the memory area of ​​the circuit 40 and the teacher signal 42 stored in the memory 41.

[0073] The calculation of the propagation channel matrix H(t) will be described in detail below. More generally, R K receivers (corresponding to the receiving section above) T A method for calculating the propagation channel matrix H(t) using K transmitters (corresponding to the above-mentioned transmitting unit) will be described. R Each of the receivers has M r It has K receive antenna elements. T Each of the transmitters has M ttransmitting antenna elements. In this case, a propagation channel matrix H(t) obtained when a MIMO (Multiple-Input and Multiple-Output) array antenna consisting of the above receiving antenna elements and the above transmitting antenna elements is arranged around a living body 50 is expressed by the following (Equation 1) and (Equation 2).

[0074]

number

number

[0075] In (Equation 1) and (Equation 2), K R and K. T indicate the number of receivers and the number of transmitters, respectively. Also, k R and k T indicates the receiver number and the transmitter number, respectively. M r and M. t respectively indicate the number of antenna elements in each receiver and the number of antenna elements in each transmitter. r and m t indicate the antenna element numbers of each receiver and each transmitter, respectively.

number

[0076] In this embodiment, a complex channel response is defined for each combination of multiple transmitters and receivers. However, the complex channel response may be expressed by a single matrix by regarding multiple transmitters as one large transmitter and multiple receivers as one large receiver.

[0077] Next, the first vector calculation unit 410 calculates the frequency response matrix F(ω) of the propagation channel matrix H(t). The frequency response matrix F(ω) is expressed by (Equation 3).

[0078]

number

[0079] Here, ω is a frequency range corresponding to the living body 50 (in other words, a frequency range corresponding to a frequency component that varies due to the biological activity of the living body 50). The frequency response matrix can be obtained by calculating the time difference of the Fourier transform or the propagation channel matrix.

[0080] Next, the first vector calculation unit 410 calculates the propagation channel matrix H(t) and the frequency response matrix F(ω) as

number

[0081]

number

[0082]

number

number

[0083] Next, the first vector calculation unit 410 calculates the vector matrix

number

number

[0084]

number

[0085] Next, the first vector calculation unit 410 performs eigenvalue decomposition on the second matrix R to obtain an eigenvector (corresponding to the first vector)

number

number

[0086]

number

number

number

[0087] where l is 1 or more, M r ×M t is an integer less than.

[0088] In this manner, the first vector calculation unit 410 calculates the first vector for both the first received signal and the teacher signal 42. The first vector calculated for the first received signal is also referred to as a test first vector, and the first vector calculated for the teacher signal 42 is also referred to as a teacher first vector.

[0089] The memory 41 may store, instead of the teacher signal 42, a first vector calculated by a first vector calculation unit 410 based on the teacher signal 42.

[0090] <Estimation section 412> The estimation unit 412 estimates a first vector

number

number

[0091] First, the estimation unit 412 calculates a complex conjugate transposed first vector

number

number

[0092]

number

[0093] Then, the estimation unit 412 obtains and extracts the maximum value of each row of the matrix obtained by (Equation 10). The extracted maximum value of the l-th row is

number

[0094] Next, the estimation unit 412 obtains the feature amount S using (Equation 11).

number

[0095] Here, L represents the number of eigenvectors to be used. If the first vectors are sorted in advance in descending order of eigenvalues, the amount of calculation can be reduced by reducing L. The estimation unit 412 performs the process of (Equation 11) on each of the teacher signals 42 stored in the memory 41, and estimates the teacher signal 42 with the maximum S as the correct organism.

[0096] In addition, the estimation unit 412 uses a predetermined k R and k T In the combination of

number

[0097] If each of S calculated from a plurality of teacher signals 42 does not exceed a preset threshold, the estimation unit 412 may output information that there is no corresponding living body as the estimation result. Furthermore, if there are a plurality of feature amounts S exceeding the above threshold, the estimation unit 412 may output a plurality of pieces of identification information about the living body 50 as the estimation result.

[0098] In addition, in the present embodiment, a case where one reception signal is used for estimation has been described, but by observing a plurality of reception signals or obtaining a plurality of first vectors by dividing the reception signal into a plurality of parts, estimation by the estimation unit 412 can be performed a plurality of times, thereby improving the estimation accuracy. More specifically, by taking the mode of a plurality of estimation results of a living body, or by adopting an estimation result with the largest average or maximum value of the feature amount S among a plurality of estimation results of a living body, it is possible to reduce estimation errors compared to the case where one reception signal is used for estimation.

[0099] In the present embodiment, the estimation unit 412 uses a feature quantity obtained by using a matrix product of the first vector, but the method is not limited to this as long as it is possible to evaluate the degree of coincidence of the first vector, and it is also possible to evaluate the degree of coincidence by machine learning such as the k-nearest neighbor method. For example, the estimation unit 412 may use the feature quantity obtained by using the matrix product of the first vector.

number

number

[0100] At this time, if the teacher signal 42 is a signal acquired with the second living body facing in various directions, the estimation unit 412 can identify the orientation of the living body 50. Also, if the teacher signal 42 is a signal acquired from a plurality of different living bodies with the orientation of the second living body fixed, the estimation unit 412 can identify the living body 50 (i.e., determine which of the plurality of living bodies it is).

[0101] In this manner, the estimation device 10A shown in FIG. 1 can identify the living body 50 by processing the signals received by the transmitting / receiving units 30A to 30H in the circuit 40.

[0102] [Operation of Estimation Device 10A] Next, the operation of the estimation device 10A configured as above will be described.

[0103] Fig. 4 is a flowchart showing an example of the operation of the estimation device 10A in this embodiment. Fig. 5 is a flowchart showing the detailed operation (operation included in step S11 in Fig. 4) of the estimation device 10A in this embodiment. Fig. 6 is a flowchart showing the detailed operation (operation included in step S12 in Fig. 4) of the estimation device 10A in this embodiment.

[0104] First, the estimation device 10A transmits M transmission signals and receives N reception signals (S10). The N reception signals correspond to first reception signals received by the N reception units, respectively.

[0105] More specifically, the estimation device 10A calculates the T )×(number of transmitting antenna elements M t Using M transmitting antenna elements, the estimation device 10A transmits a first transmission signal to a predetermined range A1 including the first living body. R )×(number of receiving antennas M r Each of the (N)=N receiving units receives, using the receiving antenna element, a first received signal including a reflected signal resulting from reflection of the first transmitted signal by the first living body for a predetermined period of time.

[0106] In this embodiment, the transmitter / receivers 30A-30H cause the antenna elements 31A-31H to transmit a transmission signal to a predetermined range A1 in a state where a first living body, which is a living body 50 to be estimated, is placed within the predetermined range A1. Then, the transmitter / receivers 30A-30H use the antenna elements 31A-31H to receive, for a predetermined period, a first reception signal including a reflected signal resulting from reflection of the first transmission signal by the first living body.

[0107] Next, the estimation device 10A calculates a first vector from the multiple first received signals acquired in step S10 and the teacher signal 42 stored in the memory 41 (S11).

[0108] The process in step S11 will be described with reference to FIG.

[0109] First, the estimation device 10A reads out from the memory 41 teacher signals 42, which are M×N second received signals obtained by N receivers receiving in advance the reflected signals of second transmitted signals transmitted from M transmitting antenna elements to a second living body, which is a known living body, reflected by the second living body. Then, the estimation device 10A calculates a frequency response matrix by Fourier transform or time difference of the first received signals acquired in step S10 and the teacher signals read out from the memory 41 (S21). Next, the estimation device 10A vectorizes each of the frequency response matrices and calculates a correlation matrix as a second matrix (S22). After that, the estimation device 10A performs eigenvalue decomposition on the second matrix (S23), and rearranges the diagonal elements in descending order to calculate a first vector (S24).

[0110] In this embodiment, the circuit 40 calculates a first vector for both the first received signal and the teacher signal 42. The first vector calculated for the first received signal is also referred to as a test first vector, and the first vector calculated for the teacher signal 42 is also referred to as a teacher first vector.

[0111] Here, eigenvalue decomposition is used in step S23, but instead, the second matrix may be subjected to singular value decomposition, and singular vectors (corresponding to the first vector) may be calculated in step S24 based on the singular values. In this case, the singular vectors may be rearranged in descending order of singular values. Note that decomposition of a matrix or decomposition of matrix elements includes at least eigenvalue decomposition or singular value decomposition.

[0112] Returning to FIG. 4, next, the estimation device 10A estimates identification information about the living body using the first received signal and the first vector of the teacher signal 42 (S12).

[0113] The process in step S12 will be described with reference to FIG.

[0114] First, the estimation device 10A calculates the absolute value of the matrix product of the first vector between the first received signal and the teacher signal 42 (S30). Next, the estimation device 10A calculates the maximum value for each row of the matrix product calculated in step S30 (S31). Next, the estimation device 10A adds up the maximum values ​​calculated in S31 in the column direction, and performs the same calculation for all combinations of transmitters and receivers, and calculates a feature by adding or multiplying all of them (S32). Next, the estimation device 10A compares the multiple feature values ​​calculated in step S32 from each of the multiple teacher signals 42 stored in the memory 41, and outputs the identification information of the living body related to the teacher signal 42 from which the largest feature value was obtained as the identification information estimated for the living body 50 (S33).

[0115] In step S33, the estimation device 10A may output information that there is no corresponding living body as the estimation result if none of the feature amounts exceeds a preset threshold value, or if the difference or ratio between the maximum feature amount and the second maximum feature amount is equal to or smaller than a certain value. Also, if there are multiple feature amounts that exceed the threshold value, the estimation device 10A may output multiple pieces of identification information about the living body 50 as the estimation result.

[0116] [Specific example of configuration] FIG. 7 is a diagram showing an example of an environment used for an estimation test by the estimation device 10A according to the embodiment.

[0117] As shown in Fig. 7, in this estimation test, four transceivers corresponding to the transceiver units 30B, 30D, 30F, and 30H (see Fig. 1) are used. Note that the number of receivers and transmitters may be any number greater than two, such as eight as shown in Fig. 1 or four.

[0118] The four transceivers are arranged side by side at the vertices of a square with one side measuring 4 m and centered around the subject 50a. The subject 50a corresponds to a living body 50 that is the subject of estimation in the estimation test, that is, a first living body.

[0119] In addition, a square patch antenna with four elements arranged vertically is used as the receiving antenna element and the transmitting antenna element corresponding to antenna elements 31B, 31D, 31F, and 31H. More specifically, the four receiving antenna elements of each of the four transceivers are square patch antennas, and are installed at a height of 0.9 m from the floor. The four transmitting antenna elements of each of the four transceivers are arranged at positions separated in the horizontal direction by one microwave wavelength from the corresponding receiving antenna element. Here, the transmitting antenna and the receiving antenna may be shared, or may be separate.

[0120] [Effects, etc.] In the environment used for the recognition test shown in Fig. 7, the estimation device 10A transmits transmission waves from each of the antenna elements of a transmitter or receiver installed at, for example, four locations around the living body 50, and receives received signals. The estimation device 10A then calculates a second matrix from the teacher signal stored in the memory 41 and the received signal from the subject 50a, which is the living body 50 to be identified, and performs eigenvalue decomposition on the calculated second matrix to calculate a first vector. Since more biological components are included in the first vector with a large eigenvalue, the estimation device 10A can increase the S / N ratio of the biological components by narrowing down the eigenvalues ​​to be used.

[0121] As described above, according to the estimation device 10A of the present embodiment, the components due to fluctuations in the living body are emphasized by frequency response transformation from the first received signal, which is a measurement signal obtained from a receiving antenna element installed around the first living body, and the teacher signal, and then the first vector is calculated by eigenvalue decomposition of the correlation matrix, and a feature amount can be obtained by calculating the inner product or matrix product. As a result, the estimation device 10A can identify the living body even under conditions where the distance between the living body and the antenna is relatively large and the S / N ratio of the living body components is relatively low. Then, the estimation device 10A can identify the living body by estimating that the first living body and the second living body used to obtain the teacher signal are the same depending on whether the maximum value of the multiple correlation coefficients exceeds a threshold value.

[0122] Furthermore, the estimation device 10A according to the present embodiment can estimate identification information about a living body 50 such as a human being, using a wireless signal such as a microwave. That is, the estimation device 10A according to the present embodiment can estimate identification information about a living body 50 such as a human being, without performing image analysis on an image captured by a camera or the like. Therefore, it can contribute to identifying a human being while protecting the privacy of the human being.

[0123] (Embodiment 2) In this embodiment, an estimation device will be described that combines biometric location estimation and biometric identification described in embodiment 1. Note that the estimation device in this embodiment has the same configuration as the estimation device 10A in embodiment 1 shown in Fig. 1, so a description of the same configuration parts will be omitted.

[0124] The estimation device of the present embodiment includes a circuit 40A shown in Fig. 8, instead of the circuit 40 of the estimation device 10A of the first embodiment. The circuit 40A includes a position estimation unit 1410, a first vector calculation unit 410, and an estimation unit 412.

[0125] [Position estimation unit 1410] The position estimation unit 1410 estimates the position of the living body 50 existing within the predetermined range A1 based on the first reception signal, which is the propagation channel matrix obtained in the same manner as in embodiment 1. A method for estimating the position of the living body 50 from the propagation channel matrix is ​​disclosed in, for example, Patent Document 6.

[0126] At least one of the transmitting antenna element and the receiving antenna element may constitute an array antenna whose horizontal directivity is controllable. In this case, the position estimation unit 1410 estimates the position of the first living body using a received signal that is a signal transmitted by a transmitting array antenna whose horizontal directivity is controllable or a received signal that is a signal received by a receiving array antenna whose horizontal directivity is controllable as a first received signal, and determines whether the position of the first living body is within a predetermined area.

[0127] For example, the antenna elements 31A to 31H included in the estimation device of this embodiment configure an array antenna whose horizontal directivity is controllable. Furthermore, as described in the first embodiment, in order to identify the living body 50, if the antenna elements 31A to 31H are also capable of controlling the vertical directivity, it is possible to achieve an effect of improving the accuracy of estimation of the living body 50. Examples of antenna elements having such characteristics are shown in Figs. 9 and 10.

[0128] FIG. 9 shows a configuration combining an array antenna in which antenna elements are arranged vertically and an array antenna in which antenna elements are arranged horizontally (specifically, antenna arrays 31-1A, 31-1B, 31-1C, and 31-1D).

[0129] FIG. 10 shows antenna array 31-2A, which uses multiple antenna elements arranged in a straight line in the horizontal direction among the antenna elements arranged in a rectangular shape (or a lattice shape), and antenna array 31-2B, which uses multiple antenna elements arranged in a straight line in the vertical direction among the antenna elements arranged in a rectangular shape (or a lattice shape).

[0130] Among the antenna arrays shown in Figures 9 and 10, signals received by array antennas in which antenna elements are arranged vertically (also called vertical arrays) (specifically, antenna arrays 31-1A and 31-1C (see Figure 9) and antenna array 31-2B (see Figure 10)) can be appropriately used for identifying living organisms.

[0131] Furthermore, among the antenna elements shown in Figures 9 and 10, signals received by array antennas (also called horizontal arrays) in which antenna elements are arranged horizontally (specifically, antenna arrays 31-1B and 31-1D (see Figure 9), and antenna array 31-2A (see Figure 10)) can be appropriately used to estimate the position of a living body.

[0132] Based on the position estimated in this way, the position estimation unit 1410 judges whether or not it is possible to start identifying the living body by a predetermined method. More specifically, the position estimation unit 1410 starts identifying the living body when the distance between the estimated position of the living body and a position set in advance or a position stored in the memory 41 is equal to or less than a predetermined threshold.

[0133] The process of identifying the living body is the same as in the first embodiment, so a description thereof will be omitted.

[0134] The first vector calculation unit 410 may calculate the first vector using the first received signal used by the position estimation unit 1410, or may newly observe the first received signal.

[0135] [Operation of the estimation device] Next, the operation of the estimation device configured as above will be described.

[0136] FIG. 11 is a flowchart showing an example of the operation of the estimation device in this embodiment.

[0137] First, the estimation device transmits M transmission signals and receives N reception signals (S110). The N reception signals correspond to first reception signals received by the N reception units, respectively.

[0138] Next, the estimation device estimates the position of the living body based on the signal received in step S110, and determines whether or not identification of the living body can be started (S111). More specifically, the estimation device determines whether or not the distance between the estimated position of the living body and a pre-set or pre-stored position is equal to or less than a predetermined threshold, and if it determines that the distance is equal to or less than the predetermined threshold, determines that identification of the living body can be started.

[0139] Next, the estimation device estimates identifying information about the living body in a manner similar to that of the estimation device 10A (S112).

[0140] [Effects, etc.] By using the estimation device in this embodiment, it is possible to use teacher data measured when in the same position as the test data, thereby reducing the influence of the biometric position and improving the accuracy of biometric identification. [Industrial Applicability]

[0141] The present disclosure can be used for an estimation device and an estimation method that estimates a living body by using a wireless signal, and in particular for an estimation device and an estimation method installed in a home appliance that performs control according to a living body, a monitoring device that detects the intrusion of a living body, and the like. [Explanation of symbols]

[0142] 10A Estimation device 30A, 30B, 30C, 30D, 30E, 30F, 30G, 30H Transmitter / receiver 31A, 31B, 31C, 31D, 31E, 31F, 31G, 31H Antenna elements 31-1A, 31-1B, 31-1C, 31-1D, 31-2A, 31-2B Antenna Array 40, 40A circuit 41 Memory 42 Teacher signal 50 Living organisms 50a Subject 410 First Vector Calculation Unit 412 Estimation Department 1410 Position estimation part

Claims

1. M (M is an integer of 1 or more) transmitting antenna elements arranged around a predetermined range including a first living body, the M transmitting antenna elements transmitting a first transmission signal to the predetermined range; N (N is an integer of 3 or more) receiving units each having a receiving antenna element and arranged around the predetermined range, the N receiving units receiving a first receiving signal including a reflected signal of the first transmitting signal reflected by the first living body for a predetermined period using the receiving antenna element; A memory that stores a plurality of teacher signals, each of which is a matrix of M×N second received signals obtained by previously receiving second received signals including a reflected signal reflected by the second living body from the M transmitting antenna elements to the second living body by the N receiving units; a first eigenvector calculation unit that calculates a plurality of teacher first eigenvectors and a test first eigenvector for each of the plurality of teacher signals and a matrix including M×N first received signals obtained by each of the N receiving units receiving the first received signals; an estimation unit that calculates a feature amount for each of a plurality of teacher first eigenvectors from the teacher first eigenvector and the test first eigenvector, thereby calculating the plurality of feature amounts, and estimates, as identification information for the first living body, identification information for the second living body used to receive a teacher signal related to a teacher first vector used to calculate a maximum feature amount among the calculated plurality of feature amounts. Estimation device.

2. The estimation unit, A first matrix is ​​calculated as an absolute value of a matrix product of the teacher first eigenvector and the test first eigenvector; using the elements of the first matrix to estimate identity information for the first organism in a predetermined manner; The estimation device according to claim 1 .

3. At least one of the M transmitting antenna elements and the N receiving units constitutes an array antenna whose vertical directivity is controllable. The estimation device according to any one of claims 1 to 2.

4. At least one of the M transmitting antenna elements and the N receiving units configures an array antenna whose directivity in a horizontal direction is controllable, The estimation device further comprises: a position estimation unit that estimates the position of the first living body based on the first received signal and determines whether the position of the first living body is within a predetermined area; The estimation device according to any one of claims 1 to 2.

5. M (M is an integer of 1 or more) transmitting antenna elements arranged around a predetermined range including a first living body, the M transmitting antenna elements transmitting a first transmission signal to the predetermined range; N (N is an integer of 3 or more) receiving units each having a receiving antenna element and arranged around the predetermined range, the N receiving units receiving a first receiving signal including a reflected signal of the first transmitting signal reflected by the first living body for a predetermined period using the receiving antenna element; A memory that stores a teacher signal, which is a matrix of M×N second received signals obtained by previously receiving second received signals including a reflected signal reflected by the second living body from the M transmitting antenna elements to the second living body, by causing the N receiving units to receive the second received signals; a first eigenvector calculation unit that calculates a teacher first eigenvector and a test first eigenvector for the teacher signal and a matrix including M×N first received signals obtained by each of the N receiving units receiving the first received signal; an estimation unit that calculates a plurality of feature amounts from the teacher first eigenvector and the test first eigenvector, and estimates identification information of the first living body by a predetermined method using the calculated plurality of feature amounts; When estimating the identification information, the estimation unit calculates a first matrix that is an absolute value of a matrix product of the teacher first eigenvector and a test first eigenvector, and estimates the identification information for the first living body by the predetermined method using elements of the calculated first matrix. Estimation device.

6. An estimation method executed by an estimation device, The estimation device includes: M (M is an integer of 1 or more) transmitting antenna elements arranged around a predetermined range including the first living body; N (N is an integer of 3 or more) receiving units each having a receiving antenna element and arranged around the predetermined range; A memory that stores a plurality of teacher signals, each of which is a matrix of M×N second received signals obtained by previously receiving second received signals including a reflected signal reflected by the second living body from the M transmitting antenna elements to the second living body by the N receiving units; Equipped with The estimation method includes: The M transmitting antenna elements transmit a first transmission signal to the predetermined range; The N receiving units receive, for a predetermined period of time, a first received signal including a reflected signal obtained by reflecting the first transmitted signal by the first living body, using the receiving antenna elements; Calculating a plurality of teacher first eigenvectors and a test first eigenvector for each of the teacher signals and a matrix including M×N first received signals obtained by each of the N receiving units receiving the first received signals; A feature amount is calculated from the teacher first eigenvector and the test first eigenvector for each of the plurality of teacher first eigenvectors, thereby calculating the plurality of feature amounts, and estimating, as the identification information for the first organism, the identification information for the second organism used to receive the teacher signal related to the teacher first vector used to calculate the maximum feature amount among the plurality of calculated feature amounts. Estimation method.

7. An estimation method executed by an estimation device, comprising: The estimation device includes: M (M is an integer of 1 or more) transmitting antenna elements arranged around a predetermined range including the first living body; N (N is an integer of 3 or more) receiving units each having a receiving antenna element and arranged around the predetermined range; A memory that stores a teacher signal, which is a matrix of M×N second received signals obtained by previously receiving second received signals including a reflected signal reflected by the second living body from the M transmitting antenna elements to the second living body, by causing the N receiving units to receive the second received signals; Equipped with The estimation method includes: The M transmitting antenna elements transmit a first transmission signal to the predetermined range; The N receiving units receive, for a predetermined period of time, a first received signal including a reflected signal obtained by reflecting the first transmitted signal by the first living body, using the receiving antenna elements; Calculating a teacher first eigenvector and a test first eigenvector for each of the teacher signal and a matrix including M×N first received signals obtained by each of the N receiving units receiving the first received signal; calculating a plurality of feature amounts from the teacher first eigenvector and the test first eigenvector, and estimating identification information for the first living body by a predetermined method using the calculated plurality of feature amounts; When estimating the identification information, a first matrix which is an absolute value of a matrix product of the teacher first eigenvector and a test first eigenvector is calculated, and the identification information for the first living body is estimated by the predetermined method using elements of the calculated first matrix. Estimation method.

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