JP7174921B2 - Sensor, estimation device, estimation method, and program - Google Patents

Description

The present disclosure relates to sensors and the like that estimate situations such as the posture and behavior of a living body by using radio signals.

As a method of knowing the position of a person, a method of using a radio signal has been studied (see Patent Documents 1 to 3, for example). Patent Literature 1 discloses a method of detecting a living body using a Doppler sensor, and Patent Literature 2 discloses a method of detecting human movement and biological information using a Doppler sensor and a filter. Patent Literature 3 discloses a technique of knowing the position and state of a person to be detected by analyzing components including Doppler shift using Fourier transform. Further, Patent Document 4 discloses a device for estimating the state of a person using a Doppler sensor, and Patent Document 5 discloses a device for estimating the posture of a person using a state estimating device. Patent Document 6 discloses a device for estimating the position of a person or an object using a camera or an RF tag.

Japanese Patent Publication No. 2014-512526 WO2014/141519 JP 2015-117972 A JP 2011-215031 A Japanese Unexamined Patent Application Publication No. 2018-8021 JP 2008-275324 A

However, there is a need for further improvement in estimating the state of a living body, such as the posture and behavior of the living body, using radio signals.

In order to achieve the above object, a sensor according to one aspect of the present disclosure is a sensor, each of which transmits a transmission signal to a predetermined range in which a living body may exist (N is a natural number of 3 or more) of the N transmission signals respectively transmitted by the N transmission antenna elements, and some of the N transmission signals transmitted by the N transmission antenna elements are reflected or scattered by the living body. a receiver having M (M is a natural number of 3 or more) receiving antenna elements each receiving N received signals including N received signals, a circuit, and a memory; N×M combinations in which the N transmitting antenna elements and the M receiving antenna elements are combined one-to-one from each of the N received signals received in each of the antenna elements in a predetermined period. For each of the above, a complex transfer function indicating the propagation characteristics between the transmitting antenna element and the receiving antenna element in the combination is calculated, and the calculated N × M complex transfer function is a component, N × M a first matrix calculation unit that sequentially calculates a first matrix; and a second matrix that corresponds to a predetermined frequency range in the first matrix that is sequentially calculated by the first matrix calculation unit. a second matrix extraction unit for sequentially extracting the second matrix corresponding to components affected by vital activity including at least one of heartbeat and body motion; a presence/absence determination unit that determines whether or not a living body exists within the predetermined range; a position estimating unit that sequentially estimates the position of the living body with respect to the sensor using a second matrix; (i) the position of the living body that is sequentially estimated by the position estimating unit; and the transmission signal generator. and the position of the receiver, a first distance indicating the distance between the position where the living body exists and the transmission signal generator sequentially estimated based on the position of A Doppler RCS that sequentially calculates a second distance indicating a distance, and (ii) sequentially calculates a Doppler RCS (Rader cross-section) value for the living body using the calculated first distance and the second distance a calculating unit for storing the sequentially estimated positions where the living body exists in the memory a predetermined number of times in order of estimation; Using the position where the living body exists, if the displacement of the position where the living body exists is greater than or equal to a predetermined value, it is determined that the living body is moving, and if the displacement is less than the predetermined value, the living body is determined to be moving. a Doppler RCS threshold setting unit for setting a Doppler RCS threshold by a predetermined method; and comparing the calculated Doppler RCS value with the set Doppler RCS threshold to determine the Doppler RCS According to at least one of a Doppler RCS threshold determination unit that determines whether a value is equal to or less than the Doppler RCS threshold, a determination result of the movement determination unit, and a determination result of the Doppler RCS threshold determination unit, the living body and a situation estimating unit that selectively performs at least one of estimating the posture of the living body and estimating the behavior of the living body.

It should be noted that the present disclosure can be implemented not only as a sensor, but also as an integrated circuit that includes processing means included in such a sensor, as a method that uses the processing means that constitute the device as steps, or as a method that uses the processing means as steps. can be realized as a program to be executed by a computer, or as information, data or a signal indicating the program. These programs, information, data and signals may be distributed via recording media such as CD-ROMs and communication media such as the Internet.

Advantageous Effects of Invention According to the present disclosure, it is possible to estimate the state of a living body in a short time and with high accuracy by using radio signals.

1 is a block diagram showing an example of the configuration of a sensor according to Embodiment 1. FIG. FIG. 2 is a block diagram showing functional configurations of circuits and memories according to the first embodiment. FIG. 3 is a diagram showing a Doppler RCS threshold set value table in the sensor of Embodiment 1. FIG. 4 is a diagram illustrating an example of posture estimation by a posture estimation unit according to Embodiment 1. FIG. 5 is a block diagram showing an example of a configuration of an action estimation unit according to Embodiment 1. FIG. FIG. 6 is a diagram for explaining an example of extracting an operation period from time-series data of height positions (Height) or Doppler RCS values. FIG. 7 is a diagram for explaining the process of converting into a direction vector. FIG. 8 is a diagram showing an example of a direction code table. FIG. 9 is a diagram showing an example of time-series data of calculated direction codes and distances. FIG. 10 is a diagram showing test data obtained by measurement and model data, which is model code. 11 is a flowchart showing an example of the operation of the sensor according to Embodiment 1. FIG. 12 is a flowchart illustrating a first example of behavior estimation processing according to Embodiment 1. FIG. 13 is a flowchart illustrating a second example of behavior estimation processing according to Embodiment 1. FIG. 14A and 14B are diagrams illustrating an example of a forward posture, transitionable postures, and actions in the action estimation unit according to Embodiment 1. FIG. 15 is a flowchart illustrating a third example of behavior estimation processing according to Embodiment 1. FIG. 16 is a flowchart showing an example of another version of the operation of the sensor according to Embodiment 1. FIG. 17 is a flowchart showing an example of another version of the operation of the sensor according to Embodiment 1. FIG. 18 is a flowchart showing an example of another version of the operation of the sensor according to Embodiment 1. FIG. FIG. 19 is a block diagram showing functional configurations of circuits and memories according to the second embodiment. 20 is a flowchart showing an example of the operation of the sensor according to Embodiment 2. FIG. 21 is a flowchart illustrating an example of operation of a posture probability estimation unit according to Embodiment 2. FIG. 22 is a diagram illustrating an example of teacher data processing used for posture probability estimation according to Embodiment 2. FIG. FIG. 23 is a diagram showing an example of normalization of teacher data and posture estimation obtained by posture probability estimation according to the second embodiment. 24 is a diagram illustrating an example of behavior probability estimation in the behavior probability estimation unit according to Embodiment 2. FIG.

(Knowledge on which the present invention is based)
The inventors conducted a detailed study of conventional techniques for estimating situations such as the posture and behavior of a living body using radio signals. As a result, although the methods of Patent Documents 1 and 2 can detect the presence or absence of a person, there is a problem that the direction, position, size, posture, etc. of a person cannot be detected. all right.

Moreover, it was found that the method of Patent Document 3 has a problem that it is difficult to detect the direction in which a living body such as a person exists and the position in which the living body exists in a short time and with high accuracy. This is because the frequency change due to the Doppler effect derived from biological activity is extremely small, and in order to observe this frequency change by Fourier transform, it is essential to observe the living body in a stationary posture for a long time (for example, several tens of seconds). be. Also, it is generally rare for a living body to continue the same posture or position for several tens of seconds.

Furthermore, Patent Document 4 discloses a device that estimates the presence/absence, rest, and activity of a person using a Doppler sensor, but there is a problem that the posture of the user cannot be determined. Moreover, in Patent Document 5, although the posture of a person can be estimated using a sensor, there is a problem that it cannot be determined whether the person is moving or acting. Patent Document 6 discloses a device for estimating the movement of people or packages using electronic tags, camera images, and the like.

As a result of repeated research on the above problems, the inventors have found that the propagation characteristics and the scattering cross section ( By estimating the direction, position, and size of the living body using Doppler RCS (Rader cross-section) value, the movement of the living body, the posture of the living body at the position where the living body exists, and the living body The present inventors have found that it is possible to estimate the state of a living body indicated by the behavior of a human body in a short period of time and with high accuracy, leading to the present disclosure.

That is, a sensor according to one aspect of the present disclosure is a sensor, and has N (N is a natural number of 3 or more) transmitting antenna elements each transmitting a transmission signal to a predetermined range in which a living body may exist. a transmission signal generator; and N reception signals including reflected signals, which are reflected or scattered by the living body, from among the N transmission signals respectively transmitted by the N transmission antenna elements. a receiver having M (M is a natural number equal to or greater than 3) receiving antenna elements that each receive the M receiving antenna elements, a circuit, and a memory, wherein the circuit includes a predetermined For each of the N×M combinations obtained by combining the N transmitting antenna elements and the M receiving antenna elements on a one-to-one basis from each of the N received signals received in the period, Calculate a complex transfer function that indicates the propagation characteristics between the transmitting antenna element and the receiving antenna element in and sequentially calculate an N × M first matrix whose components are the calculated N × M complex transfer functions and a second matrix corresponding to a predetermined frequency range in the first matrix sequentially calculated by the first matrix calculating unit, thereby obtaining the respiration, heartbeat, and body movement of the living body. a second matrix extraction unit for sequentially extracting the second matrix corresponding to the component affected by the vital activity including at least one; and determining whether or not the living body exists within the predetermined range by a predetermined method. a presence/absence determination unit that performs presence/absence determination; and the second matrix sequentially extracted by the second matrix extraction unit after the presence/absence determination unit determines that the living body exists within the predetermined range. , a position estimating unit for sequentially estimating the position of the living body with respect to the sensor; (i) the position of the living body sequentially estimated by the position estimating unit; a first distance indicating the distance between the position where the living body exists and the transmission signal generator, and a second distance indicating the distance between the living body and the receiver, which are successively estimated based on the position of the apparatus; and (ii) using the calculated first distance and the second distance, a Doppler RCS calculation unit that sequentially calculates a Doppler RCS (rader cross-section) value for the living body; and storing the estimated positions of the living body in the memory for a predetermined number of times in the estimated order, and storing the positions of the living body stored in the memory for the predetermined number of times in the memory. movement determining that the living body is moving if the displacement of the position where the living body exists using the position is greater than or equal to a predetermined value, and that the living body is not moving if the displacement is less than the predetermined value a determining unit, a Doppler RCS threshold setting unit for setting a Doppler RCS threshold by a predetermined method, and comparing the calculated Doppler RCS value with the set Doppler RCS threshold to determine whether the Doppler RCS value is the Doppler RCS estimating the posture of the living body according to at least one of a Doppler RCS threshold determination unit that determines whether or not it is equal to or less than a threshold, a determination result of the movement determination unit, and a determination result of the Doppler RCS threshold determination unit; and a situation estimation unit that selectively performs at least one of estimation of the behavior of the living body.

Therefore, the state of the living body, which is any one of the movement of the living body, the posture of the living body, and the behavior of the living body, can be estimated in a short time and with high accuracy.

Further, when the movement determination unit determines that the living body is not moving and the Doppler RCS threshold determination unit determines that the Doppler RCS value is equal to or less than the Doppler RCS threshold The posture of the living body may be estimated, and if the Doppler RCS threshold determination unit determines that the Doppler RCS value is greater than the Doppler RCS threshold, the behavior of the living body may be estimated.

Therefore, when the Doppler RCS value is equal to or less than the Doppler RCS threshold, it is determined that the living body is stationary, and the posture of the living body is estimated. Therefore, the posture of the living body can be accurately estimated. In addition, when the Doppler RCS value is greater than the Doppler RCS threshold, it is determined that the living body is moving, and the action of the living body is estimated. Therefore, the action of the living body can be estimated with high accuracy.

Further, the situation estimation unit may determine that the behavior of the living body is moving when the movement determination unit determines that the living body is moving.

Therefore, it is possible to accurately estimate that the living body is moving.

At least three transmitting antenna elements out of the N transmitting antenna elements are arranged at different positions in the vertical direction and the horizontal direction, respectively, and at least three receiving antenna elements out of the M receiving antenna elements are arranged at different positions in the vertical direction and the horizontal direction, respectively, and the memory stores Doppler RCS values, a vertical position that is the position in the vertical direction where the living body exists with respect to the sensor, and the posture of the living body. and the position estimating unit estimates a three-dimensional position including a vertical position, which is a position in the vertical direction where the living body exists with respect to the sensor, as the position where the living body exists. and the situation estimating unit estimates the posture of the living body using the calculated Doppler RCS value, the vertical position, and the information indicating the correspondence stored in the memory. good too.

Therefore, the position where the living body exists and the posture of the living body at that position can be estimated in a short time and with high accuracy.

At least three transmitting antenna elements out of the N transmitting antenna elements are arranged at different positions in the vertical direction and the horizontal direction, respectively, and at least three receiving antenna elements out of the M receiving antenna elements are arranged at different positions in the vertical direction and the horizontal direction, respectively, and the memory stores Doppler RCS values, a vertical position that is the position in the vertical direction where the living body exists with respect to the sensor, and the posture of the living body. and the position estimating unit estimates a three-dimensional position including a vertical position, which is a position in the vertical direction where the living body exists with respect to the sensor, as the position where the living body exists. Then, the situation estimating unit uses the calculated Doppler RCS value, the vertical position, and the information indicating the correspondence relationship to determine one or more predetermined postures that the living body can take. A posture probability, which is a probability of , may be estimated as the posture of the living body.

Therefore, it is possible to estimate the posture probability, which is the probability of each of the position where the living body exists and one or more postures that the living body can take at that position, in a short time and with high accuracy.

Further, the situation estimation unit sequentially estimates the posture of the living body using the sequentially calculated Doppler RCS values and the sequentially estimated positions where the living body exists, and then sequentially estimates the posture of the living body. The posture is stored in the memory, and the Doppler RCS threshold setting unit sets the Doppler RCS threshold according to the posture of the living body estimated at the latest timing among the postures of the living body stored in the memory. may

Therefore, the Doppler RCS threshold can be set to an appropriate value according to the posture of the living body.

Further, the situation estimating unit sequentially estimates the posture of the living body using the sequentially calculated Doppler RCS values and the sequentially estimated positions where the living body exists, and then sequentially estimates the posture of the living body. is stored in the memory, and then, before estimating the pose of the living body, waiting until the sequentially calculated Doppler RCS value becomes equal to or less than the Doppler RCS threshold; The posture of the living body estimated from the N received signals at the time of the change is estimated as a back posture, and the previously estimated front posture of the living body stored in the memory and the estimated The back posture may be used to estimate the behavior of the living body.

Therefore, it is possible to estimate the behavior of the living body in a short time and with high accuracy.

Further, the situation estimating unit sequentially estimates the posture of the living body using the sequentially calculated Doppler RCS values and the sequentially estimated positions where the living body exists, and then sequentially estimates the posture of the living body. is stored in the memory, waiting until the Doppler RCS value sequentially calculated becomes equal to or less than the Doppler RCS threshold, and when the Doppler RCS value becomes equal to or less than the Doppler RCS threshold, the previous One or more next actions of the living body are estimated using the estimated front posture, which is the estimated posture of the living body, and the sequentially calculated Doppler RCS value and the sequentially estimated position where the living body exists are used. , the behavior of the living body may be estimated by specifying one behavior from the estimated one or more subsequent behaviors.

Therefore, it is possible to estimate the behavior of the living body in a short time and with high accuracy.

Further, the situation estimating unit sequentially estimates the posture of the living body using the sequentially calculated Doppler RCS values and the sequentially estimated positions where the living body exists, and then sequentially estimates the posture of the living body. is stored in the memory, waiting until the Doppler RCS value sequentially calculated becomes equal to or less than the Doppler RCS threshold, and when the Doppler RCS value becomes equal to or less than the Doppler RCS threshold, the previous One or more next actions of the living body are estimated using the estimated front posture, which is the estimated posture of the living body, and the sequentially calculated Doppler RCS value and the sequentially estimated position where the living body exists are used. , a behavior probability, which is a probability of each of the estimated one or more next behaviors, may be estimated as the behavior of the living body.

Therefore, it is possible to estimate the action probability, which is the probability of each of one or more subsequent actions, in a short time and with high accuracy.

Therefore, the movement of the living body and the estimation of the posture and behavior of the living body at the position where the living body exists can be performed in a short time and with high accuracy.

The presence/absence determination unit estimates the number of living organisms existing within the predetermined range, and determines that the living organisms do not exist within the predetermined range when the number of living organisms is 0. When the number of persons is one or more, it may be determined that the living body exists within the predetermined range.

Therefore, it is possible to determine whether or not a living body exists within a predetermined range by using the estimation of the number of living bodies present within the predetermined range. This makes it possible to estimate the number of people at the same time as estimating the condition of the living body.

Further, an estimation device according to another aspect of the present disclosure is an estimation device including a circuit and a memory, wherein the circuit transmits a transmission signal to a predetermined range in which a living body may exist. Some of the N transmission signals transmitted by a transmission signal generator having N transmission antenna elements (N is a natural number of 3 or more) are reflection signals reflected or scattered by the living body. from a receiver having M (M is a natural number of 3 or more) receiving antenna elements each receiving N received signals including N and an acquisition unit that acquires received signals, and N× that combines the N transmitting antenna elements and the M receiving antenna elements from each of the acquired N received signals on a one-to-one basis. N By sequentially extracting a first matrix calculation unit that sequentially calculates a first matrix of ×M and a second matrix corresponding to a predetermined frequency range in the first matrix that is sequentially calculated by the first matrix calculation unit, a second matrix extraction unit for sequentially extracting the second matrix corresponding to components affected by vital activity including at least one of respiration, heartbeat and body movement of the living body; a presence/absence determination unit that determines whether or not a living body exists, and after the presence/absence determination unit determines that a living body exists within the predetermined range, the second matrix extraction unit sequentially extracts (i) a position estimating unit for sequentially estimating the position of the living body with respect to the transmission signal generator and the receiver using the second matrix thus obtained; a first distance indicating the distance between the living body and the transmission signal generator, and the living body and the receiver, based on the existing position, the position of the transmission signal generator, and the position of the receiver; and (ii) sequentially calculating a Doppler RCS (Rader cross-section) value for the living body using the calculated first distance and the second distance. a Doppler RCS calculation unit for storing sequentially estimated positions of the living body in the memory a predetermined number of times in the order of estimation, and the living body stored in the memory the predetermined number of times; When the displacement of the position where the living body exists is equal to or greater than a predetermined value, it is determined that the living body is moving, and when the displacement is less than the predetermined value, it is determined that the living body is not moving. a Doppler RCS threshold setting unit for setting a Doppler RCS threshold by a predetermined method; and comparing the calculated Doppler RCS value with the set Doppler RCS threshold to determine whether the Doppler RCS value is According to at least one of a Doppler RCS threshold determination unit that determines whether or not the Doppler RCS threshold is equal to or less than the Doppler RCS threshold, a determination result of the movement determination unit, and a determination result of the Doppler RCS threshold determination unit, the posture of the living body and a situation estimating unit that selectively performs one of estimating and estimating the behavior of the living body.

Therefore, the state of the living body, which is any one of the movement of the living body, the posture of the living body, and the behavior of the living body, can be estimated in a short time and with high accuracy.

It should be noted that the present disclosure can be implemented not only as a sensor, but also as an integrated circuit that includes processing means included in such a sensor, as a method that uses the processing means that constitute the device as steps, or as a method that uses the processing means as steps. can be realized as a program to be executed by a computer, or as information, data or a signal indicating the program. These programs, information, data and signals may be distributed via recording media such as CD-ROMs and communication media such as the Internet.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. It should be noted that each of the embodiments described below is a preferred specific example of the present disclosure. Numerical values, shapes, materials, components, arrangement positions and connection forms of components, steps, order of steps, and the like shown in the following embodiments are examples, and are not intended to limit the present disclosure. In addition, among the constituent elements in the following embodiments, constituent elements that are not described in independent claims representing the highest concept of the present disclosure will be described as arbitrary constituent elements that constitute more preferred embodiments. In the present specification and drawings, constituent elements having substantially the same functional configuration are denoted by the same reference numerals, thereby omitting redundant description.

(Embodiment 1)
FIG. 1 is a block diagram showing an example of the configuration of a sensor according to Embodiment 1. FIG.

As shown in FIG. 1, the sensor 10 comprises a transmitted signal generator 20, a receiver 30, and an estimator 100. As shown in FIG. Estimation device 100 comprises circuit 40 and memory 41 . The sensor 10 emits microwaves from the transmission signal generator 20 to a living body 50 such as a human, and receives reflected waves reflected or scattered by the living body 50 at the receiver 30 .

The transmission signal generator 20 has N (N is a natural number of 3 or more) transmission antenna elements 21 . The transmission signal generators 20 are N _{(N=N x × N z} ) has an array antenna composed of transmitting antenna elements 21 . That is, at least three transmitting antenna elements 21 among the N transmitting antenna elements 21 are arranged at different positions in the vertical and horizontal directions.

The receiver 30 has M receiving antenna elements 31 (M is a natural number of 3 or more). M (M=M _x ×M _z ) receivers 30 are arranged in a rectangle such that M _x receivers 30 are arranged in the horizontal direction (x direction) and M _z receivers are arranged in the vertical direction (z direction). has an array antenna composed of receiving antenna elements 31 of . That is, at least three receiving antenna elements 31 out of the M receiving antenna elements 31 are arranged at different positions in the vertical and horizontal directions.

Here, the angle between the first reference direction, which is a horizontal direction arbitrarily set with respect to the transmission signal generator 20, and the first biological direction, which is the direction from the transmission signal generator 20 to the living body 50, is defined as Let _φT . Also, the elevation angle of the living body 50, which is the angle between the vertical direction and the first living body direction, is defined as _θT . Also, the elevation angle of the living body 50 is the angle between the second reference direction, which is the direction on the horizontal plane arbitrarily set with respect to the receiver 30, and the second living body direction, which is the direction from the receiver 30 to the living body 50. be φ _R. Also, let θ _R be the angle between the vertical direction and the second living body direction. Let (x _b , y _b , z _b ) be the center coordinates of the part where the living body 50 is performing _vital activity. _R , φ _T , φ _R ) and coordinates (x _b , y _b , z _b ) are mutually transformable.

Each of the N transmitting antenna elements 21 transmits a transmission signal to a predetermined range in which a living body can exist. That is, the transmission signal generator 20 transmits N transmission signals from N different positions to a predetermined range. The predetermined range in which the living body can exist is the detection range in which the sensor 10 detects the presence of the living body.

Specifically, each of the N transmission antenna elements 21 emits microwaves as transmission signals to a living body 50 such as a human. The N transmission antenna elements 21 may transmit, as transmission signals, signals that have undergone different modulation processing for each transmission antenna element 21 . Also, each of the N transmitting antenna elements 21 may sequentially switch between a modulated signal and an unmodulated signal for transmission. Modulation processing may be performed by the transmit signal generator 20 . In this way, by making the transmission signals transmitted from the N transmission antenna elements 21 different transmission signals for each of the N transmission antenna elements 21, the transmission signals received by the receiver 30 are transmitted. Antenna element 21 can be identified. Thus, the transmit signal generator 20 may include circuitry for performing modulation processing.

Each of the M receiving antenna elements 31 receives N received signals including a reflected signal which is a signal reflected or scattered by the living body 50 among the N transmitted signals respectively transmitted by the N unique transmitting antenna elements 21. receive. The receiver 30 frequency-converts the received microwave signal to convert it into a low-frequency signal. Receiver 30 outputs to circuit 40 the signal obtained by converting it to a low frequency signal. That is, receiver 30 may include circuitry for processing received signals.

Circuitry 40 performs various processes that operate sensor 10 . The circuit 40 is composed of, for example, a processor that executes a control program and a volatile storage area (main storage device) used as a work area used when executing the control program. The volatile storage area is, for example, RAM (Random Access Memory). Note that the circuit 40 may be configured by a dedicated circuit for performing various processes for operating the sensor 10 . That is, the circuit 40 may be a circuit that performs software processing or a circuit that performs hardware processing.

The memory 41 is a non-volatile storage area (auxiliary storage device), such as a ROM (Read Only Memory), flash memory, HDD (Hard Disk Drive), and the like. The memory 41 stores, for example, information used for various processes that operate the sensor 10 .

Next, the functional configuration of the circuit 40 will be explained using FIG.

FIG. 2 is a block diagram showing a functional configuration implemented by circuits and memories according to the first embodiment.

The circuit 40 includes a first matrix calculator 410, a second matrix extractor 420, a people estimator 430, a position estimator 440, a Doppler RCS calculator 450, a movement determiner 460, and a Doppler RCS threshold value setter. 470 , a Doppler RCS threshold determination unit 480 and a situation estimation unit 520 .

The first matrix calculator 410 calculates a complex transfer function from the received signal converted to the low frequency signal. A complex transfer function represents propagation loss and phase rotation between each transmitting antenna element 21 and each receiving antenna element 31 . The complex transfer function is a complex matrix having M×N elements when the number of transmitting antenna elements is N and the number of receiving antenna elements is M. Hereinafter, this complex matrix is called a complex transfer function matrix. The estimated complex transfer function matrix is output to second matrix extraction section 420 . That is, first matrix calculation section 410 calculates each of N transmitting antenna elements 21 and M receiving antenna elements from each of a plurality of received signals received by each of M receiving antenna elements 31 in a predetermined period. 31, the N×M first matrix whose components are each complex transfer function indicating the propagation characteristic between each of the . In addition, the propagation characteristics between each of the N transmitting antenna elements 21 and each of the M receiving antenna elements 31 is defined as a one-to-one relationship between the N transmitting antenna elements 21 and the M receiving antenna elements 31. 2 shows the propagation characteristics between the transmitting antenna element 21 and the receiving antenna element 31 in each of the N×M combinations combined in .

The second matrix extractor 420 separates the complex transfer function matrix component obtained from the received signal that has passed through the living body 50 and the complex transfer function matrix component obtained from the received signal that has not passed through the living body 50 . A component that has passed through the living body 50 is a component that changes over time due to living body activity. Therefore, for example, when the components other than the living body 50 are stationary, the components passing through the living body 50 are the components other than the direct current from the components obtained by Fourier transforming the components of the complex transfer function matrix in the time direction. can be extracted by taking out In addition, the components that have passed through the living body 50 can be extracted, for example, by extracting the components whose difference from the results observed when the living body 50 is not present in the predetermined range exceeds a predetermined threshold. In this way, the second matrix extraction unit 420 extracts the complex transfer function matrix components obtained from the received signal including the reflected signal that has passed through the living body 50, and converts the extracted complex transfer function matrix components into the second matrix. calculate. That is, the second matrix extraction unit 420 sequentially extracts the second matrix corresponding to the predetermined frequency range in the first matrix sequentially calculated by the first matrix calculation unit 410, thereby obtaining the respiration, heartbeat, and body movement of the living body. A second matrix corresponding to the components affected by the vital activity including at least one is sequentially extracted.

The predetermined frequency range is, for example, frequencies derived from vital activity including at least one of respiration, heartbeat, and body movement described above. The predetermined frequency range is, for example, frequencies in the range of 0.1 Hz to 3 Hz. The second matrix extracting unit 420 extracts the second matrix corresponding to the predetermined frequency range to obtain vital activity of the part of the living body 50 caused by the movement of the heart, lungs, diaphragm, and internal organs, or Biological components affected by vital activity can be extracted. Note that the heart, lungs, diaphragm, and parts of the living body 50 that depend on the movement of internal organs are, for example, the pit of the human stomach.

Here, the second matrix extracted by the second matrix extraction unit 420 is a matrix having N×M elements, and is extracted from the complex transfer function obtained from the received signal observed in the receiver 30 during a predetermined period. be. Therefore, the second matrix is assumed to have frequency response or time response information. Note that the predetermined period is approximately half the period of at least one of breathing, heartbeat, and body movement of the living body.

The second matrix calculated by second matrix extraction section 420 is output to population estimation section 430 . The number-of-people estimation unit 430 estimates the number of people using, for example, the eigenvalues or eigenvectors obtained using the first matrix calculated by the first matrix calculation unit 410 or the second matrix extracted by the second matrix extraction unit 420. may be performed. The number-of-people estimation unit 430 is an example of a presence/absence determination unit that determines whether or not a living body exists within a predetermined range. The number-of-persons estimation unit 430 estimates the number of living organisms existing within a predetermined range, determines that there are no living organisms within the predetermined range when the estimated number of living organisms is 0, and determines that the estimated number of living organisms is 1. If the above is the case, it may be determined that the living body exists within the predetermined range.

After the number-of-persons estimation unit 430 determines that the living body exists within the predetermined range, the position estimation unit 440 uses the second matrix sequentially extracted by the second matrix extraction unit 420 to determine the presence of the living body 50 with respect to the sensor 10. Estimate the position where Position estimator 440 estimates both the angle of departure θ _T from transmission signal generator 20 and the angle of arrival θ _R to receiver 30, and adds a triangle to the estimated angle of departure θ _T and angle of arrival θ _R. Estimate the position of the living body 50 by using the method. The position of the living body 50 estimated here is a three-dimensional position including the vertical position, which is the position in the vertical direction where the living body exists with respect to the sensor 10 . The positions of the living body 50 sequentially estimated by the position estimator 440 may be stored in the memory 41 .

The Doppler RCS calculator 450 sequentially calculates a Doppler Scattering Cross Section (Doppler RCS) value using the sequentially extracted second matrix and the sequentially estimated positions. Specifically, in order to calculate the Doppler RCS value, the Doppler RCS calculator 450 uses the position sequentially estimated by the position estimator 440, the position of the transmission signal generator 20, and the position of the receiver 30. Based on this, the distance RT indicating the first distance, which is the distance between the sequentially estimated position where the living body 50 exists and the transmission signal generator 20, and the sequentially estimated position where the living body 50 exists and the receiver 30 A distance RR indicating a second distance, which is a distance, is sequentially calculated. The Doppler RCS calculator 450 calculates the propagation distance from the successively calculated distance RT and distance RR, and successively calculates the Doppler RCS value using the calculated propagation distance and the intensity of the biological component. Note that the position of the transmission signal generator 20 and the position of the receiver 30 may be stored in the memory 41 in advance.

The movement determining unit 460 stores the positions of the living body 50 sequentially estimated by the position estimating unit 440 in the memory 41 in the estimated order. The movement determination unit 460 determines whether or not the living body 50 is moving using the positions of the living body 50 stored in the memory 41 a predetermined number of times (for example, L times). The movement determination unit 460 refers to the L positions of the living body 50 estimated over a predetermined period of time, such as the past five seconds, among the plurality of stored positions of the living body 50, and determines the latest position and the previous position. position, the distance between the position one before and the position two before, ..., and the distance between the position L-1 and L before Then, the total sum of all the calculated L-1 distances is calculated as the moving distance. In other words, the movement determination unit 460 calculates the movement distance by integrating the distance between two temporally adjacent positions using all of the L positions sampled in the predetermined time. Note that the moving distance can also be said to be the displacement of the position where the living body 50 exists.

Then, for example, when the calculated moving distance is equal to or greater than a predetermined value such as 1 m, the movement determination unit 460 determines that the living body 50 has been moving during the past five seconds of a predetermined time. If the calculated moving distance is less than a predetermined value, the movement determination unit 460 determines that the living body has not moved during the predetermined time.

Although movement determination section 460 calculates the movement distance using all of a plurality of positions sampled at a predetermined time, the present invention is not limited to this. It may be calculated as a movement distance, or by extracting several points out of L positions for a predetermined time and accumulating the distance between two temporally adjacent points among the extracted several points. You may calculate the moving distance by .

The Doppler RCS threshold setting section 470 sets the Doppler RCS threshold by a predetermined method. Specifically, the Doppler RCS threshold setting unit 470 sets the Doppler RCS threshold according to the biological condition estimated at the latest timing stored in the memory 41 .

As the Doppler RCS threshold, a threshold corresponding to each of a plurality of different conditions of a living body may be set. For example, as shown in FIG. The threshold may be set to a value obtained by multiplying the average of the values by a fixed ratio, such as 1.5 times (150%). FIG. 3 is a diagram showing a Doppler RCS threshold set value table in the sensor of the first embodiment.

At this time, since the optimal value of the ratio to be multiplied by the threshold differs depending on the front posture of the application destination, it may be determined as appropriate for each front posture of the application destination. For example, the ratio for calculating the Doppler RCS threshold when the front posture in the lowest row in FIG. The ratio for calculating may be 1.2 times (120%). This is because the Doppler RCS value calculated when the front posture in the bottom row is lying down and the next posture is rolling over is smaller than the Doppler RCS values in other postures.

The Doppler RCS threshold determination unit 480 compares the Doppler RCS value calculated by the Doppler RCS calculation unit 450 with the Doppler RCS threshold set by the Doppler RCS threshold setting unit 470, and the Doppler RCS value is equal to or less than the Doppler RCS threshold. Determine whether or not

Situation estimating section 520 determines one of the posture of living body 50 and the action of living body 50 according to at least one of the determination result of movement determining section 460 and the determination result of Doppler RCS threshold determining section 480. Estimate the condition of the living body. Situation estimation section 520 has posture estimation section 490 and action estimation section 500 .

If the movement determining unit 460 determines that the living body 50 is not moving and the Doppler RCS threshold determining unit determines that the Doppler RCS value is equal to or less than the Doppler RCS threshold, the posture estimating unit 490 determines the posture of the living body 50. is estimated. In this case, the posture estimation unit 490 can estimate that the position of the living body 50 has hardly changed and that the posture of the living body 50 is stationary with no movement. pose can be estimated. Posture estimation section 490 uses the method described in Patent Document 5, for example, to calculate the Doppler RCS value calculated by Doppler RCS calculation section 450, the vertical position of living body 50, and the Doppler RCS value stored in memory 41. and the information 42 indicating the correspondence between the vertical position of the living body 50 and the posture of the living body 50, the posture of the living body 50 is estimated.

In Patent Document 5, the attitude is estimated based on the area of the vertical position and the Doppler RCS value stored in the memory 41. For example, as shown in FIG. Alternatively, the posture of the living body 50 associated with the training data closest to the vertical position and Doppler RCS value of the living body may be estimated as the posture of the living body 50 . FIG. 4 is a diagram showing an example of posture estimation by the posture estimation unit according to Embodiment 1. In FIG.

The behavior estimation unit 500 estimates the behavior of the living body 50 when the Doppler RCS threshold determination unit 480 determines that the Doppler RCS value is greater than the Doppler RCS threshold. In this case, the behavior estimating unit 500 can estimate that the living body 50 is moving and is in motion, and therefore can estimate the behavior of the living body 50 . The action estimating unit 500 refers to the calculated Doppler RCS value and the estimated vertical position of the living body 50 stored in the memory 41, and stores the transition vector of the Doppler RCS value and the vertical position of the living body 50 in advance. Then, the behavior of the living body 50 is estimated by calculating the correlation with the teacher vector.

FIG. 5 is a block diagram showing an example of the configuration of action estimation section 500 according to Embodiment 1. As shown in FIG.

The behavior estimating unit 500 uses time-series data indicating temporal changes in the position estimated by the position estimating unit 440 and the Doppler RCS value calculated by the Doppler RCS calculating unit 450, and the correspondence stored in the memory 41 in advance. The behavior of the living body 50 is estimated using the information 42 indicating the situation. The action estimation unit 500 has a motion period extraction unit 510 , a direction code calculation unit 511 and a motion comparison unit 512 .

As shown in FIG. 6, the motion period extracting unit 510 extracts the position of the living body 50 estimated by the position estimating unit 440 or the temporal change width of the Doppler RCS value calculated by the Doppler RCS calculating unit 450 to a predetermined value. is extracted as an action period during which the user is performing an action. Note that FIG. 6 is a diagram for explaining an example of extracting an operation period from time-series data of a height position (Height) or a Doppler RCS value.

For example, when the motion period extraction unit 510 extracts the motion period using the height position or the Doppler RCS value, which is the vertical position, the obtained position of the living body 50 or the Doppler RCS value is extracted to avoid the influence of instantaneous noise. For time-series data, for example, using a median filter, an FIR filter, an average value, etc., the height position and the noise component of the Doppler RCS value are removed, and the change section of the height information after filtering and the Doppler RCS A change interval may be extracted as an operation period of the living body. That is, the motion period extracting unit 510 uses time series data obtained by removing instantaneous noise components using a predetermined filter from a plurality of vertical positions or a plurality of Doppler RCS values obtained in time series. to extract the operation period.

Note that the operation period extraction unit 510 is effective when it is desired to limit the period to be estimated for the purpose of reducing the amount of calculation, but it is not necessarily provided. In other words, when posture estimation is performed for the entire interval, it goes without saying that the movement period extraction unit 510 may be omitted and the estimation may be performed for the entire interval.

The direction code calculation unit 511 calculates the vertical position (height position) obtained from the estimated position of the living body 50 and the calculated Doppler position, which is the temporal change in the motion period extracted by the motion period extraction unit 510 . A time-varying RCS value is converted to a directional vector using a predetermined method. Specifically, the direction code calculation unit 511 two-dimensionally plots the height position and the Doppler RCS value as shown in FIG. θ is calculated. The direction code calculation unit 511 calculates, for example, from the first coordinates p1 (H1, R1) indicated by the height position H1 and the Doppler RCS value R1 at the first timing, In the trajectory to the second coordinate p2 (H2, R2) indicated by the height position H2 and the Doppler RCS value R2, the first coordinate p1 (H1, R1) and the second coordinate p2 (H2, R2) The distance ΔP between them and the direction θ when looking from the first coordinate p1 (H1, R1) to the second coordinate p2 (H2, R2) are calculated to convert to a direction vector. FIG. 7 is a diagram for explaining the process of converting into a direction vector.

Next, the direction code calculation unit 511 calculates a direction code by normalizing the converted direction vector. Specifically, the direction code calculation unit 511 calculates the direction code by referring to the direction code table shown in FIG. For example, the direction code calculator 511 identifies the direction code with the closest direction θ among the direction codes indicated by 1 to 8. FIG. FIG. 8 is a diagram showing an example of a direction code table.

The direction code calculation unit 511 obtains direction code time-series data as shown in FIG. 9 by calculating the direction code and the distance ΔP as described above. FIG. 9 is a diagram showing an example of time-series data of calculated direction codes and distances. At this time, the direction code calculation unit 511 may normalize the direction code in order to avoid the influence of individual differences.

The operation comparison unit 512 compares the time-series data of the direction code calculated by the direction code calculation unit 511 with the information 42 indicating the response status stored in the memory, thereby obtaining the corresponding data in the information 42 indicating the response status. The behavior of the living body 50 is estimated by identifying the behavior associated with the time-series data.

The information 42 indicating the response status stored in the memory 41 includes a plurality of model codes indicating the vertical position, which is the vertical position of the living body 50 with respect to the sensor 10, and temporal changes in the Doppler RCS value; It is information indicating the correspondence status with the behavior of the living body 50 . Also, the behavior of the living body 50 associated with the information 42 indicating the response status includes falling, sitting on a chair, sitting on the floor, standing up from a chair, standing up from the floor, jumping, and changing direction. . In other words, the action estimation unit 500 indicates the position estimated by the position estimation unit 440, the temporal change in the Doppler RCS value calculated by the Doppler RCS calculation unit 450, and the correspondence status stored in advance in the memory 41. Using the information 42, estimate which behavior the living body 50 performed: falling, sitting on a chair, sitting on the floor, standing up from a chair, standing up from the floor, jumping, and changing direction. . Note that the model code is expressed as time-series data as shown in FIG.

Note that the behavior estimation unit 500 may estimate that the behavior of the living body 50 is moving when the movement determination unit 460 determines that the living body 50 is moving. In this case, the behavior estimating unit 500 may estimate that the behavior of the living body 50 is walking if the posture of the living body 50 estimated immediately before it is determined that the living body 50 is moving is standing. . Further, if the posture of the living body 50 estimated immediately before it is determined that the living body 50 is moving is the sitting position, the action estimating unit 500 may estimate that the living body 50 is moving in a wheelchair. . Further, when the posture of the living body 50 estimated immediately before it is determined that the living body 50 is moving is the lying position, the behavior estimating unit 500 estimates that the behavior of the living body 50 is rolling over or crawling. may

Note that the circuit 40 obtains time-series data by repeatedly performing the above-described processes in the respective units 410 to 500 at a plurality of different timings. For example, the circuit 40 obtains time-series data consisting of a plurality of time-series positions and a plurality of time-series Doppler RCS values by repeating the process at a predetermined sampling period.

と定義する。ここで、ｔは時刻を表す。式１の各成分をフーリエ変換すると、

のような周波数応答行列が得られる。ここでｆは周波数を表しており、周波数応答行列の各成分は複素数である。この周波数応答行列には、生体５０を経由する伝搬成分と、生体５０以外を経由する伝搬成分との両方が含まれている。生体以外が静止していると考えられる場合、周波数応答行列の直流成分、すなわちＧ（０）は生体以外の伝搬成分を主として含んでいるものと考えられる。これは、生体の呼吸、心拍および体動の少なくともいずれかを含むバイタル活動によってドップラシフトが発生するため、生体を経由する成分はｆ＝０以外に含まれると考えられるからである。さらに、生体の呼吸または心拍の周波数およびその高調波を考えると、ｆ＜３〔Ｈｚ〕の範囲に生体由来の成分が多く存在するものと考えられる。したがって、例えば０〔Ｈｚ〕＜ｆ＜３〔Ｈｚ〕の所定周波数範囲のＧ（ｆ）を取り出せば、生体成分を効果的に抽出することができる。 Next, details of the principle of operation of the sensor 10 of Embodiment 1 will be described using mathematical formulas. Here, a method of extracting biological components using Fourier transform will be shown. The processing described here is performed by circuit 40 . The complex transfer function matrix between the transmission signal generator 20 and the receiver 30 is

defined as Here, t represents time. Fourier transforming each component of Equation 1 yields

A frequency response matrix such as where f represents frequency and each component of the frequency response matrix is a complex number. This frequency response matrix includes both propagation components passing through the living body 50 and propagation components passing through other than the living body 50 . When the object other than the living body is considered to be stationary, the DC component of the frequency response matrix, ie G(0), is considered to mainly contain the propagation component other than the living body. This is because the Doppler shift is caused by vital activity including at least one of respiration, heartbeat, and body movement of the living body, and components passing through the living body are considered to be included other than f=0. Furthermore, considering the frequency of respiration or heartbeat of a living body and its harmonics, it is considered that there are many components derived from the living body in the range of f<3 [Hz]. Therefore, if G(f) in a predetermined frequency range of 0 [Hz]<f<3 [Hz], for example, is extracted, the biological component can be effectively extracted.

のようにベクトル形式に並び替える。これを生体成分ベクトルと定義する。ここで｛・｝^Ｔは転置を表す。生体成分ベクトルｇ（ｆ）から相関行列を、

によって計算する。ここで、｛・｝^Ｈは複素共役転置を表す。さらにＲは０〔Ｈｚ〕＜ｆ＜３〔Ｈｚ〕の間で平均化されている。この平均化によって、後述の位置推定精度が向上することが知られている。次に、算出した相関行列Ｒを固有値分解することで、当該相関行列Ｒの固有ベクトルＵとその複素共役転置ベクトルＵ^Ｈを算出する。 Next, a method of estimating the body position using the body component G(f) will be described. Let the biological component matrix G(f) be

Rearrange in vector format like . This is defined as a biological component vector. Here, {·} ^T represents transposition. A correlation matrix is obtained from the biological component vector g(f) as

Calculate by where {·} ^H represents the complex conjugate transpose. Furthermore, R is averaged between 0 [Hz]<f<3 [Hz]. It is known that this averaging improves the accuracy of position estimation, which will be described later. Next, by eigenvalue decomposition of the calculated correlation matrix R, the eigenvector U of the correlation matrix R and its complex conjugate transposed vector ^UH are calculated.

The eigenvector in Equation 5 is represented by Equation 6 below.

と表される。ここで、ｄｉａｇ［・］とは［・］内の要素を対角項に持つ対角行列を表す。回路４０は、以上の情報を用いて、検出対象となる生体５０の位置推定を行う。ここでは一例としてＭＵＳＩＣ法に基づく位置推定方法について説明する。ＭＵＳＩＣ法ではステアリングベクトルと呼ばれる方向ベクトルと式６で示した固有ベクトルとを用いることによって方向や位置を推定する方法である。式３で示した生体成分ベクトルは、本来のＭ×Ｎ行列を変形して得られる。生体５０の位置推定を行うためには、これに対応してステアリングベクトルを定義する必要がある。送信信号発生器２０から生体５０へ向かう（θＴ、φＴ）方向を示すステアリングベクトルと、受信機３０から生体５０へ向かう（θＲ、φＲ）方向を示すステアリングベクトルとは、それぞれ、

と表される。ここで、

と表される。ここで、ｋは波数を表し、ｄ_Ｔｘおよびｄ_Ｔｚはそれぞれ送信アンテナ素子２１のｘ方向およびｚ方向における素子間隔を表し、ｄ_Ｒｘおよびｄ_Ｒｚはそれぞれ受信アンテナ素子３１のｘ方向およびｚ方向における素子間隔を表す。なお、本実施の形態では素子間隔が同一の方向においては一定のリニアアレーアンテナを想定している。 Here, u _i represents the eigenvector of the i-th column, and the number of elements is NM. D is a diagonal matrix whose diagonal elements are eigenvalues,

is represented. Here, diag[·] represents a diagonal matrix having elements in [·] as diagonal terms. The circuit 40 uses the above information to estimate the position of the living body 50 to be detected. Here, as an example, a position estimation method based on the MUSIC method will be described. The MUSIC method is a method of estimating a direction and a position by using a direction vector called a steering vector and an eigenvector shown in Equation (6). The biological component vector shown in Equation 3 is obtained by transforming the original M×N matrix. In order to estimate the position of the living body 50, it is necessary to define a corresponding steering vector. The steering vector indicating the (θT, φT) direction from the transmission signal generator 20 to the living body 50 and the steering vector indicating the (θR, φR) direction from the receiver 30 to the living body 50 are respectively:

is represented. here,

is represented. where k represents the wavenumber, _dTx and _dTz represent the element spacing in the x and z directions of the transmitting antenna element 21, respectively, and _dRx and _dRz represent the x and z directions of the receiving antenna element 31, respectively. represents the element spacing. In this embodiment, it is assumed that the element spacing is a constant linear array antenna in the same direction.

となる。ステアリングベクトルａ（θ_Ｔ，φ_Ｔ，θ_Ｒ，φ_Ｒ）は、ＭＮ×１の要素を持つベクトルであり、出発角θＴ、φＴと到来角θＲ、φＲとの４変数を持つ関数となる。以降、ａ（θ_Ｔ，φ_Ｔ，θ_Ｒ，φ_Ｒ）をステアリングベクトルと定義する。検出範囲内に存在する生体の数をＬとすると、評価関数

によって生体位置を特定する。ここで、式１１の評価関数はＭＵＳＩＣスペクトラムと呼ばれており、送信信号発生器２０および受信機３０のそれぞれから検出対象へ向かう方向の組み合わせ（θ_Ｔ，θ_Ｒ）における極大点を探索することで、極大に対応するθ_Ｔおよびθ_Ｒから、三角法を用いて、鉛直位置を含む、送信信号発生器２０および受信機３０から見た生体５０の３次元位置を特定できる。 _dTx represents, for example, the interval between two adjacent transmitting antenna elements 21 among the multiple transmitting antenna elements 21 in the x direction. d _Tz represents, for example, the interval between two adjacent transmitting antenna elements 21 among the multiple transmitting antenna elements 21 in the z direction. Also, d _Rx represents, for example, the distance between two adjacent receiving antenna elements 31 in the x direction among the plurality of receiving antenna elements 31 . Also, d _Rz represents, for example, the interval between two receiving antenna elements 31 adjacent to each other in the z direction among the plurality of receiving antenna elements 31 . Taking the Kronecker product of these steering vectors gives

becomes. The steering vector a(θ _T , φ _T , θ _R , φ _R ) is a vector having MN×1 elements, and is a function with four variables of departure angles θT, φT and arrival angles θR, φR. Henceforth, a((theta) _T ,(phi) _T ,(theta) _R ,(phi) _R ) is defined as a steering vector. Assuming that the number of living organisms present within the detection range is L, the evaluation function

The body position is specified by Here, the evaluation function of Equation 11 is called a MUSIC spectrum, and searching for a maximum point in a combination of directions (θ _T , θ _R ) from the transmission signal generator 20 and the receiver 30 toward the detection target. , from the θ _T and θ _R corresponding to the maxima, trigonometry can be used to identify the three-dimensional position of living body 50 as seen from transmitter 20 and receiver 30, including vertical position.

と計算することができる。ここでρｉｊは行列

の（ｉ，ｊ）番目の要素を表している。一方、ｊ番目の送信アンテナ素子２１から生体５０を経由してｉ番目の受信アンテナ素子３１に到達する電力は、

と表される。ここで、Ｐｔは、送信電力を表す。なお、全ての送信アンテナ素子２１から等しい電力が送信されているものとする。Ｇｔは送信信号発生器２０の動作利得を表し、Ｇｒは受信機３０の動作利得を表し、Ｒ１は送信信号発生器２０から生体５０までの距離を表し、Ｒ２は生体５０から受信機３０までの距離を表す。距離Ｒ１および距離Ｒ２は数１３により推定した位置から容易に計算することができる。すると、式１２で定義される電力伝達係数は、ρｉｊ＝Ｐｒｉｊ／Ｐｔで表されるので、散乱断面積は、

により計算することができる。なお、ここで取り扱う散乱断面積では、生体５０全体の散乱断面積ではなく、呼吸、心拍、体動などの生体５０のバイタル活動の影響を受けることにより生じた変動成分に対応するドップラ散乱面積だけが考慮されている。さらに、全要素を平均して、

によって平均散乱断面積を求める。以降、

をドップラＲＣＳと呼称する。 Furthermore, the Doppler RCS value is obtained from Equation 12, and the posture of the living body 50 is estimated from the position of the living body 50 and the Doppler RCS value. Assuming that the frequency range to be extracted is f1 to f2 (f1<f2), the power transfer coefficient can be obtained from the channel component reflected from the living body and observed.

can be calculated as where ρij is the matrix

represents the (i, j)-th element of . On the other hand, the power reaching the i-th receiving antenna element 31 from the j-th transmitting antenna element 21 via the living body 50 is

is represented. Here, Pt represents transmission power. It is assumed that equal power is transmitted from all transmitting antenna elements 21 . Gt represents the operating gain of the transmission signal generator 20, Gr represents the operating gain of the receiver 30, R1 represents the distance from the transmission signal generator 20 to the living body 50, and R2 represents the distance from the living body 50 to the receiver 30. represents distance. The distances R1 and R2 can be easily calculated from the positions estimated by Equation (13). Then, the power transfer coefficient defined by Equation 12 is represented by ρij=Prij/Pt, so the scattering cross section is

can be calculated by Note that the scattering cross section dealt with here is not the scattering cross section of the entire living body 50, but only the Doppler scattering area corresponding to the fluctuating component caused by the influence of the vital activity of the living body 50 such as respiration, heartbeat, and body movement. is taken into account. Furthermore, averaging over all elements,

Obtain the average scattering cross section by from,

is called the Doppler RCS.

It goes without saying that, for example, when the vital component and the body motion component of the living body are to be further separated and measured, the frequency range of Expression 14 is adjusted and the subsequent processing is performed.

The method of behavior estimation will be described below.

By continuously estimating the Doppler RCS value σ and the height z of the living body 50 at a plurality of different timings by the above-described method, the trajectory of the σ-z characteristic can be observed. At this time, when the living body is in a stationary state, the Doppler RCS value hardly changes. Therefore, when the living body is in action, that is, when the living body is in motion, that is, the flow of the trajectory points with large fluctuations in the Doppler RCS value is extracted. With respect to this trajectory point group, let ΔPi be the trajectory point movement amount, which is the distance between the i−1 th trajectory point and the i th trajectory point. An angle between them is defined as an angle parameter αi, which is defined by Equations 20 and 21, respectively.

The value of the angle parameter is then used to assign a direction code to the direction of movement of the trajectory point. Direction codes are assigned to angles by dividing 360° into eight and assigning numbers 1 to 8 to each direction. At this time, in order to prevent the code from frequently changing when moving in the vertical and horizontal directions, the code may not be bordered in that direction. Since there are individual differences in the speed of action in the action of the living body 50, the difference in speed of action is taken into account in order to avoid misrecognition due to the number of trajectory points varying with the speed of the action even for the same action. Orientation codes may be normalized. For example, from the original direction code string c _j (j=1 to j _max ) obtained by direction estimation, a normalized code string consisting of K terms is to generate Here, j _max is the number of trajectory points, which varies depending on the operation time. A normalized code string C _k (k=1, 2, . . . , K) is created from the i-th locus movement amount ΔPi and the total sum of locus point movement amounts ΔP _sum as follows.

1) For j=1, the normalized code string in the k range that satisfies Equation 22 is the code for j=1 in the original code string.

2) In the range of j from 2 to _jmax , the normalized code string in the range of k that satisfies the following equation (23) is the code for each j. However, ΔP _sum satisfies Expression 24.

The behavior of the living body 50 is estimated by comparing a normalized sequence (test data) composed of K terms created from the trajectory point data with a model data sequence composed of K terms corresponding to each of a plurality of behaviors. For the model data sequence, the behavior is measured multiple times while performing each of the multiple behaviors in advance, and the most common direction code in each term of the normalized code sequence obtained by measuring the behavior multiple times is This is the model data for that term. The maximum difference is 4 since the direction codes are circular. Formula 25 is used to calculate the difference between the direction code number and the actual number. However, when δC _i >4, Equation 26 is used.

However, C _{test, i} indicates the _i -th element of the test data string, and C _{model, i} indicates the i-th element of the model data string. Next, the sum of the squares of the direction code differences between the test data and the model data is calculated as the deviation shown in Equation (27). For example, as shown in FIG. 12, by comparing the test data and the model data, the action determination deviation E is calculated by Equation (27). FIG. 12 is a diagram showing test data obtained by measurement and model data, which is model code.

Then, an action corresponding to the model data string with the smallest deviation is output as an estimation result.

Next, the operation of the sensor 10 according to Embodiment 1 will be described using a flowchart.

11 is a flowchart showing an example of the operation of the sensor according to Embodiment 1. FIG.

In the sensor 10, the N transmission antenna elements 21 of the transmission signal generator 20 transmit N transmission signals using the N transmission antenna elements 21 to a predetermined range in which the living body 50 can exist.

The M reception antenna elements 31 of the receiver 30 receive N reception signals including a plurality of reflected signals reflected by the living body 50 from the N transmission signals transmitted by the transmission signal generator 20 .

The circuit 40 selects between each of the N transmitting antenna elements 21 and each of the M receiving antenna elements 31 from each of the N received signals received by each of the M receiving antenna elements 31 in a predetermined period. (S11).

The circuit 40 sequentially extracts the second matrix corresponding to the predetermined frequency range in the first matrix to correspond to the components affected by vital activity including at least one of respiration, heartbeat and body movement of the living body 50. A second matrix is sequentially extracted (S12).

The circuit 40 uses the first matrix or the second matrix to perform presence/absence determination to determine whether or not the living body 50 exists within a predetermined range as the effective range of the sensor 10 (S13). In step S13, number estimation may be performed to estimate the number of living organisms existing within a predetermined range. After determining that the living body 50 exists within the predetermined range (Yes in S13), the circuit 40 proceeds to step S14, and after determining that the living body 50 does not exist within the predetermined range (No in S13), Return to step S11 (S13).

In step S14, the circuit 40 sequentially estimates the position of the living body 50 with respect to the sensor 10 using the sequentially extracted second matrix (S14). Then, the circuit 40 stores the sequentially estimated position of the living body 50 in the memory 41 for a predetermined number of times in the order of estimation.

The circuit 40 calculates a distance indicating the distance between the living body 50 and the transmission signal generator 20 based on the position of the living body 50, the position of the transmission signal generator 20, and the position of the receiver 30, which are successively estimated. RT and the distance RR indicating the distance between the living body 50 and the receiver 30 are successively calculated, and the Doppler RCS value for the living body 50 is successively calculated using the calculated distance RT and distance RR (S15).

The circuit 40 uses the positions of the living body 50 stored in the memory 41 a predetermined number of times to determine whether or not the displacement of the position of the living body 50 is less than a predetermined value (S16). The circuit 40 determines that the living body 50 is moving if the displacement is 1 m or more in 5 seconds, for example (No in S16), and returns to step S11. By using this result, the behavior of the living body 50 may be determined to be moving. For example, if the displacement is less than 1 m in 5 seconds (Yes in S16), the circuit 40 determines that the living body 50 has not moved, and proceeds to the next step S17.

The circuit 40 refers to the previous posture and the average value of the Doppler RCS values for a predetermined number of past times stored in the memory 41, and sets the Doppler RCS threshold by a predetermined method (S17). At this time, the Doppler RCS threshold may be set to a predetermined value for each past attitude, or obtained by multiplying the average value of the past Doppler RCS values by a predetermined ratio, such as 1.5 times. A value may be set.

Circuit 40 compares the calculated Doppler RCS value with the set Doppler RCS threshold, and determines whether the Doppler RCS value is equal to or less than the Doppler RCS threshold (S18).

When the calculated Doppler RCS value is equal to or less than the Doppler RCS threshold (Yes in S18), the circuit 40 performs posture estimation processing for estimating the posture of the living body 50 by the posture estimation unit 490 (S19).

When the calculated Doppler RCS value is larger than the Doppler RCS threshold (No in S18), the circuit 40 performs an action estimation process for estimating the action of the living body 50 by the action estimator 500 (S20).

A specific example of the processing in the circuit 40 has already been explained in the explanation of the functional configuration of the circuit 40, so the explanation is omitted.

As described above, in steps S16 to S20, the estimation of the posture of the living body 50 and the estimation of the behavior of the living body 50 are performed according to at least one of the determination result of the movement determination and the determination result of the Doppler RCS threshold determination. At least one is selectively performed.

FIG. 12 is a flow chart showing a first example of details of the action estimation process.

The circuit 40 extracts a vertical position from the estimated positions or a period in which the temporal change in the calculated Doppler RCS value is greater than a predetermined value as an operation period during which the living body 50 is moving (S21).

circuit 40 converts the temporal changes in the extracted motion period, which are the vertical position obtained from the estimated position and the calculated Doppler RCS value, into directional vectors using a predetermined method; A direction code is calculated by normalizing the converted direction vector (S22).

The circuit 40 compares the calculated time-series data of the direction code with the information 42 indicating the response status stored in the memory, so that the information 42 indicating the response status is associated with the time-series data. By specifying the behavior, the behavior of the living body 50 is estimated (S23).

Next, the pre-learning operation of the sensor 10 for acquiring the information 42 indicating the response status will be described.

The circuit 40 receives an input for designating a predetermined operation from an input means (not shown). Thereby, the circuit 40 recognizes that the operation performed during the predetermined period is the operation indicated by the received input. Next, processes similar to steps S11 to S22 and steps S21 and S22 of the operation of the sensor 10 described above are sequentially performed.

Next, the circuit 40 stores in the memory 41, as teacher data, information indicating the corresponding state obtained by associating the motion received from the input means with the calculated time-series data of the direction code. By performing the above pre-learning for each motion of the living body, information indicating the response status is generated and stored in the memory 41 .

According to the sensor 10 according to the present embodiment, estimation of the posture of the living body 50 and estimation of the action of the living body 50 are performed in accordance with at least one of the determination result of the movement determination and the determination result of the Doppler RCS threshold determination. At least one is selectively performed. Therefore, the state of the living body, which is any one of the movement of the living body 50, the posture of the living body 50, and the behavior of the living body 50, can be estimated in a short time and with high accuracy.

According to the sensor 10 according to the present embodiment, the position where the living body 50 exists and the situation of the living body at that position, such as the presence/absence, rest, movement, posture, and action, can be estimated in a short time and with high accuracy.

The sensor 10 detects the presence of the living body 50 by detecting moving parts. For this reason, for example, by using this, it is possible to estimate whether a human being is alive and in which posture of upright, sitting on a chair, sitting cross-legged, or supine. As a result, confirmation of human survival can be effectively performed. In addition, since it is possible to confirm the survival of a person without analyzing the image captured by the camera, it is possible to confirm the survival of the person while protecting the privacy of the person.

(Modification 1 of Embodiment 1)
In the first embodiment, in the action estimation processing by the circuit 40, the trajectory of the combination of the vertical position of the living body 50 and the Doppler RCS value is stored in advance in the memory 41 as teacher data. and the calculated correlation with the trajectory of the combination of the Doppler RCS values, but the present invention is not limited to this. The action estimation unit 500 may perform, for example, the process shown in the flow of FIG. 13 as the process of estimating the action of the living body 50 .

13 is a flowchart illustrating a second example of behavior estimation processing according to Embodiment 1. FIG.

Posture estimation section 490 of circuit 40 stores the estimated posture in memory 41 each time the posture is estimated.

The action estimation unit 500 refers to the latest posture of the living body 50 stored in the memory 41 and acquires the latest posture as the previous posture used to estimate the action of the living body 50 (S31).

Then, the action estimation unit 500 sequentially acquires the Doppler RCS values that are calculated sequentially (S32). The action estimation unit 500 acquires the Doppler RCS values stored in the memory 41 from the memory 41 in the order of calculation.

The action estimation unit 500 determines whether the acquired Doppler RCS value is equal to or less than the Doppler RCS threshold (S33).

When it is determined that the Doppler RCS value is equal to or less than the Doppler RCS threshold (Yes in S33), the action estimating section 500 causes the posture estimating section 490 to estimate the posture of the living body 50, and uses the estimated posture as the back posture of the action. (S34). In other words, the behavior estimating unit 500 waits until the living body 50 stands still by waiting until the Doppler RCS value becomes equal to or less than the Doppler RCS threshold. The posture of the living body 50 estimated from is estimated as the back posture. The action estimating unit 500 acquires the posture after the living body 50 stands still as the back posture, so that the back posture can be acquired with high accuracy.

The behavior estimation unit 500 then estimates the behavior of the living body 50 using the acquired front posture and the estimated back posture (S35). For example, the action estimating unit 500 refers to the correspondence situation in which the front posture, the back posture, and the action shown in the table shown in FIG. 14 are associated with each other. By specifying the attached action, the action of the living body 50 is estimated. Note that FIG. 14 is a diagram showing an example of a combination of the front posture and the back posture and an example of the corresponding state of the action in another example of the action estimation process according to the first embodiment.

(Modification 2 of Embodiment 1)
Further, for example, as shown in FIG. 14, the action estimation unit 500 is limited to the back posture, which is the posture after the action that occurs thereafter, as shown in FIG. It is also possible to narrow down the possible action options. That is, the rear posture in FIG. 14 can also be read as a transitionable posture. By using this, when the front posture is specified, as in the flow shown in FIG. 15, the action may be estimated by dividing the action options that occur after the specified front posture.

15 is a flowchart illustrating a third example of behavior estimation processing according to Embodiment 1. FIG.

The action estimation unit 500 refers to the latest posture of the living body 50 stored in the memory 41 and acquires the latest posture as the previous posture used to estimate the action of the living body 50 (S41). When the front posture is posture A, action estimation section 500 proceeds to step S42. For example, posture A is standing.

The behavior estimation unit 500 performs steps S42 and S43. Steps S42 and S43 are the same as steps S32 and S33, respectively, so description thereof is omitted.

Since the front posture acquired in step S44 is the standing position, the action estimation unit 500 refers to the correspondence situation in FIG. , behavior is estimated (S44). Specifically, posture estimating section 490, which estimates the back posture, next estimates the posture with the closest estimation result among the sitting position and the lying position as the back posture. For example, either the sitting position or the lying position is estimated as the rear posture of the living body 50 by comparing the teacher data of the sitting position and the lying position with the combination of the vertical position of the living body 50 and the Doppler RCS value.

Similarly, when the front posture is posture B, action estimation section 500 proceeds to step S45. Steps S45 to S47 differ only in the front posture, and the processing itself is the same as that of steps S42 to S44, so a description thereof will be omitted.

(Modification 3 of Embodiment 1)
It should be noted that the flowchart showing the operation of the sensor 10 shown in Embodiment 1 is an example, and as shown in FIGS. By storing in the memory 41, post-processing can be shared with a server or another computer, and Doppler RCS threshold determination can be performed first as shown in FIG.

16 is a flowchart showing an example of another version of the operation of the sensor according to Embodiment 1. FIG.

As shown in FIG. 16, the circuit 40 of the sensor 10 may separate the processing of steps S11 to S15 and the processing of steps S16 to S20 in the flowchart described in FIG. That is, the first device that executes the processes of steps S11 to S15 and the second device that executes the processes of steps S16 to S20 may be different.

First, the first device executes the processes of steps S11 to S15. Next, the processing results obtained in steps S11 to S15 are stored in memory (S101). Note that the memory used in step S101 may be the memory provided in the first device or the memory provided in the second device. It may be a memory provided in a different device.

The second device then reads the latest result from memory (S102). The second device then executes the processes of steps S16 to S20.

Each of the first device and the second device is composed of a circuit and a memory.

17 is a flowchart showing an example of another version of the operation of the sensor according to Embodiment 1. FIG.

As shown in FIG. 17, the circuit 40 of the sensor 10 may separate the processing of steps S11 to S19 and the processing of step S20 in the flowchart described in FIG. That is, the third device that executes the processes of steps S11 to S19 and the fourth device that executes the process of step S20 may be different.

First, the first device executes the processes of steps S11 to S19. Next, the processing results obtained in steps S11 to S19 are stored in memory (S111). Note that the memory used in step S101 may be the memory provided in the third device or the memory provided in the fourth device. It may be a memory provided in a different device.

Next, the fourth device reads the latest result from memory (S112).

The fourth device then sets a Doppler RCS threshold (S113), and determines whether the Doppler RCS value in the latest results is less than or equal to the Doppler RCS threshold (S114).

If the Doppler RCS value is greater than the Doppler RCS threshold (No in S114), the fourth device executes the process of step S20. If the Doppler RCS value is equal to or less than the Doppler RCS threshold (Yes in S114), the process returns to step S112.

18 is a flowchart showing an example of another version of the operation of the sensor according to Embodiment 1. FIG.

As in steps S121 and S122 shown in FIG. 18, the setting of the Doppler RCS threshold and the determination of the Doppler RCS threshold may be performed prior to the determination of whether or not the living body 50 is moving.

In this case, as in step S17, the circuit 40 refers to the previous posture and the average value of the Doppler RCS values for a predetermined number of past times stored in the memory 41, and determines the Doppler RCS threshold value by a predetermined method. is set (S121).

Next, as in step S18, the circuit 40 compares the calculated Doppler RCS value with the set Doppler RCS threshold, and determines whether the Doppler RCS value is equal to or less than the Doppler RCS threshold (S122). ).

When the calculated Doppler RCS value is equal to or less than the Doppler RCS threshold (Yes in S122), the circuit 40 performs posture estimation processing for estimating the posture of the living body 50 by the posture estimation unit 490 (S19), and returns to step S11. .

If the calculated Doppler RCS value is greater than the Doppler RCS threshold (No in S18), the circuit 40 executes step S16, and if the movement amount is equal to or less than the threshold (Yes in S16), the action of the living body 50 is estimated. (S20) and returns to step S11.

If the movement amount is greater than the threshold (No in S16), the circuit 40 determines that the movement is in progress, and returns to step S11.

(Embodiment 2)
In the circuit 40 according to the first embodiment, one posture or one action of the living body 50 is estimated at a certain timing. can be estimated. The posture probability of the living body 50 is the probability that each of one or more predetermined postures that the living body 50 can assume occurs. The action probability of the living body 50 is the probability that each of one or more predetermined actions that the living body 50 can take is occurring.

FIG. 19 is a block diagram showing functional configurations of circuits and memories according to the second embodiment.

Circuit 40A in the second embodiment differs from circuit 40 in the first embodiment in that posture estimation section 490 and action estimation section 500 are replaced with posture probability estimation section 491 and action probability estimation section 501, respectively. .

20 is a flowchart showing an example of the operation of the sensor according to Embodiment 2. FIG.

Embodiment 2 is different in that steps S19a and S20a are performed instead of steps S19 and S20, respectively. Details of step S19a will be described with reference to FIGS.

FIG. 21 is a flowchart illustrating an example of posture probability estimation processing in a posture probability estimation unit. 22 is a diagram showing an example of teacher data used for posture probability estimation according to Embodiment 2. FIG.

The posture probability estimation unit 491 first normalizes teacher data for estimating the posture (S51). Posture probability estimation section 491 may perform step S51 each time teacher data is updated. In the normalization of the teacher data, for example, as shown in FIG. 22, in order to suppress the variation in the height direction in the original teacher data, for example, the data of 70% or more and 30% or less of the upper and lower parts of the teacher data of each posture. delete. The range of data to be deleted, which is set at this time, differs according to the installation situation and application of the sensor 10A. Next, Eqs. 27 and 28 are used to normalize the height information and the Doppler RCS information.

Here, Z ⁱ _std is the i-th normalized teacher data of the vertical position, Z ⁱ is the i-th teacher data of the vertical position, μ _z is the mean of the vertical position, σ _z is the variance of the vertical position, σ ⁱ _std is the Doppler RCSi-th normalized teacher data, σ ⁱ is the Doppler RCSi-th teacher data, μ _σ is the Doppler RCS average, and σ _σ is the Doppler RCS variance. An example of calculation results is shown in FIG. FIG. 23 is a diagram showing an example of normalization of teacher data and posture estimation obtained by posture probability estimation according to the second embodiment.

In FIG. 23, for example, when the measured data is positioned at a star, the posture probability estimation unit 491 extracts data of 100 points in the vicinity thereof and estimates the posture probability (S52). For example, if 70 of the extracted 100 points indicate standing and 30 points indicate sitting, posture probability estimation section 491 generates an estimated posture probability value composed of 70% standing and 30% sitting. It is calculated as the posture of the living body 50 .

Next, FIG. 24 is a flowchart showing an example of action probability estimation processing in the action probability estimation unit.

In Embodiment 2, as described above with reference to FIGS. .

The action probability estimation unit 501 refers to the latest posture probability estimation value of the living body 50 stored in the memory 41, and calculates a plurality of initial posture probabilities indicated by the plurality of posture probabilities included in the latest posture probability estimation value. A posture is acquired (S61).

Action probability estimation section 501 calculates the probability of an action that can occur for each posture probability of a plurality of initial postures. For example, in step S61, the posture probability of initial posture A is estimated as P _a1 , the posture probability of initial posture B is estimated as P _b1 , the posture probability of initial posture C is estimated as P _c1 , and the posture probability of initial posture D is estimated as P c1 . Let the probability be estimated as P _d1 .

The initial posture A will be described below.

The behavior probability estimation unit 501 performs steps S62 and S63. Steps S62 and S63 are different from steps S32 and S33, respectively, in that the vertical position is further recorded in step S62, but otherwise similar. That is, by executing S62 and S63, the action probability estimation unit 501 waits while recording until the Doppler RCS value becomes equal to or less than the Doppler RCS threshold, and when the Doppler RCS value becomes equal to or less than the Doppler RCS threshold, to step S64. At step 64, the deviation E for action determination is calculated using a predetermined method or equation (26).

Next, action probability estimating section 501 obtains initial posture correction term B _i as posture probability using Equation 29 based on posture probability estimation value P _i of the initial posture referred to from memory 41 .

At this time, C may be any natural number. Further, the post-action posture probability estimator 491 obtains the posture probability after the action is completed, and the post-action posture correction term _Ai is obtained in the same manner as in Equation 29 (S64). In the present embodiment, since the behavior determination deviation E is a variable that indicates the correlation between teacher data and a certain code, the behavior when E is the minimum is the result. Therefore, any formula may be used as long as B _i is also a variable that minimizes when the most probable posture is obtained.

After that, the probability-corrected deviation E _pi is obtained by Equation (30). As a result, P _A for the initial posture A in step S66 is calculated.

Here, _Ei is the result of obtaining the behavior determination deviation E for each code of each training data.

In this way, in steps S61 to S66, the posture probability P _a1 of the initial posture A, and the action probabilities P _a21 , P _a22 , . Then, posture probabilities P _a31 , P _a32 , . Then, in step _S66 , the posture probability P _a1 of the initial posture A, one of the plurality of action probabilities P _a21 , _{P a22} , . The minimum value of the products of all possible combinations of the three probabilities with one of them is calculated as the action probability _PA .

S67 to S71 corresponding to steps S62 to S66 are repeated for the initial posture B in the same manner as for the initial posture A, and the processing is similarly repeated for the other initial postures C, D, .

Behavior probability estimation unit 501 _compares P _A , P _B , P _C , P _D , . is specified as the behavior of the living body (S72).

INDUSTRIAL APPLICABILITY The present disclosure can be used for a sensor and an estimation method for estimating the direction and position of a moving object using radio signals. In particular, direction estimation methods and directions installed in measuring instruments that measure the direction and position of moving objects, including living organisms and machines, home appliances that perform control according to the direction and position of moving objects, and monitoring devices that detect intrusion of moving objects. It can be used for an estimation method, a position estimation method, and an estimation device using a scattering cross section.

REFERENCE SIGNS LIST 10 sensor 20 transmission signal generator 21 transmission antenna element 30 receiver 31 reception antenna element 40, 40A circuit 41 memory 42 information indicating response status 50 living body 410 first matrix calculator 420 second matrix extractor 430 population estimator 440 position Estimation unit 450 Doppler RCS calculation unit 460 Movement determination unit 470 Doppler RCS threshold setting unit 480 Doppler RCS threshold determination unit 490 Attitude estimation unit 491 Attitude probability estimation unit 500 Action estimation unit 501 Action probability estimation unit 510 Motion period extraction unit 511 Direction code calculation Unit 512 Motion comparison unit 520 Situation estimation unit

Claims (13)

a sensor,
a transmission signal generator having N (N is a natural number of 3 or more) transmission antenna elements each transmitting a transmission signal to a predetermined range in which a living body may exist;
Each receives N received signals including reflected signals in which some of the N transmitted signals respectively transmitted by the N transmitting antenna elements are reflected or scattered by the living body. a receiver having M receiving antenna elements (M is a natural number of 3 or more);
a circuit;
with memory and
The circuit is
A one-to-one combination of the N transmission antenna elements and the M reception antenna elements from each of the N reception signals received in each of the M reception antenna elements in a predetermined period For each of the N×M combinations, a complex transfer function indicating the propagation characteristics between the transmitting antenna element and the receiving antenna element in the combination is calculated, and the calculated N×M complex transfer function is used as a component. , a first matrix calculator that sequentially calculates a first matrix of N×M;
By sequentially extracting a second matrix corresponding to a predetermined frequency range in the first matrix sequentially calculated in the first matrix calculation unit, vital activity including at least one of respiration, heartbeat and body movement of the living body a second matrix extraction unit that sequentially extracts the second matrix corresponding to the affected component;
a presence/absence determination unit that determines whether or not a living body exists within the predetermined range by a predetermined method;
After the presence/absence determination unit determines that the living body exists within the predetermined range, the position of the living body with respect to the sensor is determined using the second matrix sequentially extracted by the second matrix extraction unit. a position estimation unit that sequentially estimates;
(i) the position of the living body successively estimated based on the position of the living body successively estimated by the position estimation unit, the position of the transmission signal generator, and the position of the receiver; and the transmission signal generator, and a second distance indicating the distance between the living body and the receiver, and (ii) the calculated first distance and the a Doppler RCS calculation unit that sequentially calculates a Doppler RCS (Rader cross-section) value for the living body using a second distance;
The positions of the living body that are sequentially estimated are stored in the memory for a predetermined number of times in the estimated order, and the positions of the living body that are stored in the memory for the predetermined number of times are used to determine the positions of the living body. a movement determination unit that determines that the living body is moving when the displacement is equal to or greater than a predetermined value, and determines that the living body is not moving when the displacement is less than the predetermined value;
a Doppler RCS threshold setting unit for setting a Doppler RCS threshold by a predetermined method;
a Doppler RCS threshold determination unit that compares the calculated Doppler RCS value with the set Doppler RCS threshold and determines whether the Doppler RCS value is equal to or less than the Doppler RCS threshold;
A situation in which at least one of the estimation of the posture of the living body and the estimation of the action of the living body is selectively performed according to at least one of the determination result of the movement determination section and the determination result of the Doppler RCS threshold determination section. an estimator; and a sensor. The situation estimation unit
When the movement determining unit determines that the living body is not moving and the Doppler RCS threshold determining unit determines that the Doppler RCS value is equal to or less than the Doppler RCS threshold, the posture of the living body is estimated. do,
The sensor according to claim 1, wherein the behavior of the living body is estimated when the Doppler RCS threshold determination unit determines that the Doppler RCS value is greater than the Doppler RCS threshold. The situation estimation unit
3. The sensor according to claim 1, wherein when the movement determination unit determines that the living body is moving, the action of the living body is determined to be moving. At least three transmitting antenna elements out of the N transmitting antenna elements are arranged at different positions in the vertical direction and the horizontal direction, respectively;
At least three receiving antenna elements out of the M receiving antenna elements are arranged at different positions in the vertical direction and the horizontal direction, respectively;
The memory stores Doppler RCS values and information indicating a correspondence relationship between a vertical position, which is a position in the vertical direction where the living body exists with respect to the sensor, and a posture of the living body,
The position estimating unit estimates, as the position where the living body exists, a three-dimensional position including a vertical position, which is a position in the vertical direction where the living body exists with respect to the sensor,
The situation estimation unit estimates the posture of the living body using the calculated Doppler RCS value, the vertical position, and the information indicating the correspondence stored in the memory.
4. A sensor according to any one of claims 1-3. At least three transmitting antenna elements out of the N transmitting antenna elements are arranged at different positions in the vertical direction and the horizontal direction, respectively;
At least three receiving antenna elements out of the M receiving antenna elements are arranged at different positions in the vertical direction and the horizontal direction, respectively;
The memory stores Doppler RCS values and information indicating a correspondence relationship between a vertical position, which is a position in the vertical direction where the living body exists with respect to the sensor, and a posture of the living body,
The position estimating unit estimates, as the position where the living body exists, a three-dimensional position including a vertical position, which is a position in the vertical direction where the living body exists with respect to the sensor,
The situation estimating unit uses the calculated Doppler RCS value, the vertical position, and the information indicating the correspondence relationship to determine the probability of each of one or more predetermined postures that the living body can take. estimating the posture probability as the posture of the living body,
4. A sensor according to any one of claims 1-3. The situation estimating unit sequentially estimates the posture of the living body using the sequentially calculated Doppler RCS values and the sequentially estimated positions where the living body exists, and then calculates the sequentially estimated posture of the living body. stored in said memory;
The Doppler RCS threshold setting unit sets the Doppler RCS threshold according to the posture of the living body estimated at the latest timing among the postures of the living body stored in the memory.
6. A sensor according to any one of claims 1-5. The situation estimation unit
After sequentially estimating the posture of the living body using the sequentially calculated Doppler RCS values and the sequentially estimated positions where the living body exists, storing the sequentially estimated postures of the living body in the memory;
Next, before estimating the posture of the living body, it waits until the Doppler RCS value that is sequentially calculated becomes equal to or less than the Doppler RCS threshold, and determines if the Doppler RCS value becomes equal to or less than the Doppler RCS threshold. estimating the posture of the living body estimated from the received signal of as a back posture,
estimating the behavior of the living body using the previously estimated front posture of the living body stored in the memory and the estimated back posture;
7. A sensor according to any one of claims 1-6. The situation estimation unit
After sequentially estimating the posture of the living body using the sequentially calculated Doppler RCS values and the sequentially estimated positions where the living body exists, storing the sequentially estimated postures of the living body in the memory;
waiting until the Doppler RCS value calculated sequentially becomes equal to or less than the Doppler RCS threshold;
when the Doppler RCS value becomes equal to or less than the Doppler RCS threshold, estimating one or more next actions of the living body using a previous posture, which is a posture of the living body previously estimated and stored in the memory;
Behavior of the living body by specifying one behavior from the one or more next behaviors estimated by using the Doppler RCS value that is sequentially calculated and the position that the living body is located that is sequentially estimated. 7. The sensor according to any one of claims 1 to 6, which estimates the . The situation estimation unit
After sequentially estimating the posture of the living body using the sequentially calculated Doppler RCS values and the sequentially estimated positions where the living body exists, storing the sequentially estimated postures of the living body in the memory;
waiting until the Doppler RCS value calculated sequentially becomes equal to or less than the Doppler RCS threshold;
when the Doppler RCS value becomes equal to or less than the Doppler RCS threshold, estimating one or more next actions of the living body using a previous posture, which is a posture of the living body previously estimated and stored in the memory;
Using the sequentially calculated Doppler RCS value and the sequentially estimated position where the living body exists, an action probability, which is the probability of each of the estimated one or more next actions, is estimated as the action of the living body. A sensor according to any one of claims 1 to 6. The presence/absence determination unit estimates the number of living organisms present in the predetermined range, determines that the living organisms do not exist in the predetermined range when the number of living organisms is 0, and determines that the living organisms do not exist within the predetermined range. 10. The sensor according to any one of claims 1 to 9, wherein when the number is 1 or more, it is determined that the living body exists within the predetermined range. An estimating device comprising a circuit and a memory,
The circuit is
Among the N transmission signals transmitted by a transmission signal generator having N transmission antenna elements (N is a natural number of 3 or more) each transmitting a transmission signal to a predetermined range in which a living body may exist From a receiver having M receiving antenna elements (M is a natural number of 3 or more) each receiving N received signals including reflected signals whose part of transmitted signals is reflected or scattered by the living body, an acquiring unit that acquires the N received signals received in each of the M receiving antenna elements in a predetermined period;
From each of the acquired N received signals, for each of N×M combinations in which the N transmitting antenna elements and the M receiving antenna elements are combined one-to-one, the calculating a complex transfer function indicating propagation characteristics between the transmitting antenna element and the receiving antenna element, and sequentially calculating an N×M first matrix whose components are the calculated N×M complex transfer functions; 1 matrix calculation unit;
By sequentially extracting a second matrix corresponding to a predetermined frequency range in the first matrix sequentially calculated in the first matrix calculation unit, vital activity including at least one of respiration, heartbeat and body movement of the living body a second matrix extraction unit that sequentially extracts the second matrix corresponding to the affected component;
a presence/absence determination unit that determines whether or not a living body exists within the predetermined range by a predetermined method;
After it is determined by the presence/absence determination unit that the living body exists within the predetermined range, the second matrix extracted sequentially by the second matrix extraction unit is used for the transmission signal generator and the receiver. a position estimation unit that sequentially estimates the position where the living body exists;
(i) based on the position of the living body, the position of the transmission signal generator, and the position of the receiver sequentially estimated by the position estimating unit, the relationship between the living body and the transmission signal generator; A first distance indicating a distance and a second distance indicating a distance between the living body and the receiver are sequentially calculated, and (ii) using the calculated first distance and the second distance, the a Doppler RCS calculator that sequentially calculates a Doppler RCS (Rader cross-section) value for a living body;
storing the sequentially estimated positions of the living body in the memory for a predetermined number of times in the order of estimation, and using the positions of the living body stored in the memory for the predetermined number of times to shift the position of the living body; a movement determination unit that determines that the living body is moving when is equal to or greater than a predetermined value, and determines that the living body is not moving when is less than the predetermined value;
a Doppler RCS threshold setting unit for setting a Doppler RCS threshold by a predetermined method;
a Doppler RCS threshold determination unit that compares the calculated Doppler RCS value with the set Doppler RCS threshold and determines whether the Doppler RCS value is equal to or less than the Doppler RCS threshold;
Situation estimation that selectively performs one of the estimation of the posture of the living body and the estimation of the action of the living body according to at least one of the determination result of the movement determination section and the determination result of the Doppler RCS threshold determination section. and an estimating device. An estimation method performed in an estimation device comprising a circuit and a memory, comprising:
Among the N transmission signals transmitted by a transmission signal generator having N transmission antenna elements (N is a natural number of 3 or more) each transmitting a transmission signal to a predetermined range in which a living body may exist From a receiver having M receiving antenna elements (M is a natural number of 3 or more) each receiving N received signals including reflected signals whose part of transmitted signals is reflected or scattered by the living body, Obtaining the N received signals received in a predetermined period at each of the M receiving antenna elements,
From each of the acquired N received signals, for each of N×M combinations in which the N transmitting antenna elements and the M receiving antenna elements are combined one-to-one, the calculating a complex transfer function indicating propagation characteristics between the transmitting antenna element and the receiving antenna element, and sequentially calculating an N×M first matrix whose components are the calculated N×M complex transfer functions;
By sequentially extracting the second matrix corresponding to the predetermined frequency range in the sequentially calculated first matrix, it corresponds to the component affected by the vital activity including at least one of respiration, heartbeat and body movement of the living body. successively extracting the second matrix that
Presence/absence determination is performed to determine whether or not the living body exists within the predetermined range by a predetermined method,
sequentially estimating the position of the living body with respect to the transmission signal generator and the receiver by using the sequentially extracted second matrix after it is determined that the living body exists within the predetermined range;
a first distance indicating the distance between the living body and the transmission signal generator based on the position of the living body, the position of the transmission signal generator, and the position of the receiver, which are sequentially estimated; and , sequentially calculating a second distance indicating the distance between the living body and the receiver;
sequentially calculating a Doppler RCS (Rader cross-section) value for the living body using the calculated first distance and the second distance;
storing the sequentially estimated positions where the living body exists in the memory for a predetermined number of times in order of estimation;
Using the position of the living body stored in the memory for the predetermined number of times, if the displacement of the position of the living body is greater than or equal to a predetermined value, it is determined that the living body is moving and is less than the predetermined value. In the case of , movement determination is performed to determine that the living body is not moving,
setting a Doppler RCS threshold by a predetermined method;
comparing the calculated Doppler RCS value with the set Doppler RCS threshold, and performing Doppler RCS threshold determination for determining whether the Doppler RCS value is equal to or less than the Doppler RCS threshold;
An estimation method that selectively performs one of estimating the posture of the living body and estimating the behavior of the living body according to at least one of a determination result of the movement determination and a determination result of the Doppler RCS threshold determination. An estimation method performed in an estimation device comprising a circuit and a memory, comprising:
Among the N transmission signals transmitted by a transmission signal generator having N transmission antenna elements (N is a natural number of 3 or more) each transmitting a transmission signal to a predetermined range in which a living body may exist From a receiver having M receiving antenna elements (M is a natural number of 3 or more) each receiving N received signals including reflected signals whose part of transmitted signals is reflected or scattered by the living body, Obtaining the N received signals received in a predetermined period at each of the M receiving antenna elements,
From each of the acquired N received signals, for each of N×M combinations in which the N transmitting antenna elements and the M receiving antenna elements are combined one-to-one, the calculating a complex transfer function indicating propagation characteristics between the transmitting antenna element and the receiving antenna element, and sequentially calculating an N×M first matrix whose components are the calculated N×M complex transfer functions;
By sequentially extracting the second matrix corresponding to the predetermined frequency range in the sequentially calculated first matrix, it corresponds to the component affected by the vital activity including at least one of respiration, heartbeat and body movement of the living body. successively extracting the second matrix that
Presence/absence determination is performed to determine whether or not the living body exists within the predetermined range by a predetermined method,
sequentially estimating the position of the living body with respect to the transmission signal generator and the receiver by using the sequentially extracted second matrix after it is determined that the living body exists within the predetermined range;
a first distance indicating the distance between the living body and the transmission signal generator based on the position of the living body, the position of the transmission signal generator, and the position of the receiver, which are sequentially estimated; and , sequentially calculating a second distance indicating the distance between the living body and the receiver;
sequentially calculating a Doppler RCS (Rader cross-section) value for the living body using the calculated first distance and the second distance;
storing the sequentially estimated positions where the living body exists in the memory for a predetermined number of times in order of estimation;
Using the position of the living body stored in the memory for the predetermined number of times, if the displacement of the position of the living body is greater than or equal to a predetermined value, it is determined that the living body is moving and is less than the predetermined value. In the case of , movement determination is performed to determine that the living body is not moving,
setting a Doppler RCS threshold by a predetermined method;
comparing the calculated Doppler RCS value with the set Doppler RCS threshold, and performing Doppler RCS threshold determination for determining whether the Doppler RCS value is equal to or less than the Doppler RCS threshold;
selectively performing one of estimating the posture of the living body and estimating the action of the living body according to at least one of the determination result of the movement determination and the determination result of the Doppler RCS threshold determination; program to run.

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