JP2020008556A - Sensor, estimation device, estimation method, and program - Google Patents

Abstract

To provide a sensor and the like capable of estimating the posture of a living body in a short time and with high accuracy by using radio signals.SOLUTION: A sensor 10 includes: a transmit signal generation unit 20 that has N (N is a natural number of 3 or more) transmission antenna elements 21 each transmitting a transmission signal in a predetermined range where a living body can exist; a receiver unit 30 that has M (M is a natural number of 3 or more) antenna elements 31 each receiving N reception signals in which some of the N transmitted signals that are transmitted by the N transmission antenna elements 21 includes reflection signals reflected by the living body; a circuit 40; and a memory 41. The circuit 40 is configured to estimate the movement of the living body and the posture and behavior of the living body at the position where the living body exists.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a sensor and the like for estimating a situation such as a posture and an action of a living body by using a radio signal.

  As a method of knowing the position of a person or the like, a method using a radio signal is being studied (for example, see Patent Documents 1 to 3). Patent Document 1 discloses a method of detecting a living body using a Doppler sensor, and Patent Document 2 discloses a method of detecting human motion and biological information using a Doppler sensor and a filter. Patent Literature 3 discloses a technique for analyzing a component including a Doppler shift using a Fourier transform to know the position and state of a person to be detected. Patent Document 4 discloses an apparatus for estimating a person's state using a Doppler sensor, and Patent Document 5 discloses an apparatus for estimating a person's posture using a state estimating apparatus. Patent Literature 6 discloses an apparatus that estimates the position of a person or an object using a camera or an RF tag.

JP 2014-512526 A International Publication No. 2014/141519 JP-A-2005-117792 JP 2011-215031 A JP 2018-80221A JP 2008-275324 A

  However, further improvement is required to estimate the state of the living body such as the posture and behavior of the living body by using the wireless signal.

  In order to achieve the above object, a sensor according to an embodiment of the present disclosure is a sensor, and transmits N transmission signals to a predetermined range where a living body can exist (N is a natural number of 3 or more). A transmission signal generator having a transmission antenna element, and a transmission signal of a part of the N transmission signals transmitted by the N transmission antenna elements is reflected or scattered by the living body. A receiver having M (M is a natural number of 3 or more) reception antenna elements each receiving N reception signals including the reception signal, a circuit, and a memory, wherein the circuit includes the M reception signals. An N × M set in which the N transmission antenna elements and the M reception antenna elements are combined in a one-to-one correspondence from each of the N reception signals received in each of the antenna elements for a predetermined period. For each of the combinations, a complex transfer function indicating a propagation characteristic 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 calculation unit for sequentially calculating the first matrix of the first matrix, and a second matrix corresponding to a predetermined frequency range in the first matrix sequentially calculated in the first matrix calculation unit. A second matrix extraction unit for sequentially extracting the second matrix corresponding to a component affected by vital activity including at least one of respiration, heartbeat, and body movement; and a living body within the predetermined range by a predetermined method. A presence / absence determination unit for performing presence / absence determination for determining whether or not to perform, and after the presence / absence determination unit determines that a living body exists within the predetermined range, the second matrix extraction unit sequentially performs A position estimating unit for sequentially estimating a position of the living body with respect to the sensor by using the output second matrix; and (i) a position of the living body sequentially estimated by the position estimating unit; The position of the transmission signal generator, the position of the receiver, based on the first distance indicating the distance between the transmission signal generator and the position where the living body is sequentially estimated, and the living body and the A second distance indicating a distance to a receiver is sequentially calculated, and (ii) a Doppler RCS (Rader cross-section) value for the living body is sequentially calculated using the calculated first distance and the second distance. The Doppler RCS calculation unit to be calculated, and the sequentially estimated position of the living body is stored in the memory a predetermined number of times in the estimated order, and the position of the living body stored in the memory the predetermined number of times is used. If the displacement of the position where the living body is present is equal to or greater than a predetermined value, the living body is determined to be moving, and if less than the predetermined value, a movement determining unit that determines that the living body is not moving, A Doppler RCS threshold value setting unit that sets a Doppler RCS threshold value by a predetermined method, and compares the calculated Doppler RCS value with the set Doppler RCS threshold value, and the Doppler RCS value is equal to or less than the Doppler RCS threshold value. Doppler RCS threshold value determination unit that determines whether or not the posture of the living body is estimated according to at least one of the determination result of the movement determination unit, and the determination result of the Doppler RCS threshold value determination unit. And a situation estimating unit for selectively performing at least one of the behavior estimation.

  It should be noted that the present disclosure is not only realized as a sensor, but also as an integrated circuit including a processing unit provided in such a sensor, or as a method in which the processing unit configuring the device is performed as a step. Can be realized as a program to be executed by a computer, or can be realized as information, data or a signal indicating the program. These programs, information, data, and signals may be distributed via a recording medium such as a CD-ROM or a communication medium such as the Internet.

  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 a wireless signal.

FIG. 1 is a block diagram illustrating an example of a configuration of the sensor according to the first embodiment. FIG. 2 is a block diagram showing a functional configuration of a circuit and a memory according to the first embodiment. FIG. 3 is a diagram illustrating a Doppler RCS threshold value set value table in the sensor according to the first embodiment. FIG. 4 is a diagram illustrating an example of posture estimation by the posture estimating unit according to the first embodiment. FIG. 5 is a block diagram illustrating an example of a configuration of the behavior estimation unit according to Embodiment 1. FIG. 6 is a diagram for describing an example of extracting an operation period from time-series data of a height position (Height) or a Doppler RCS value. FIG. 7 is a diagram for explaining a process of converting into a direction vector. FIG. 8 is a diagram illustrating an example of the direction code table. FIG. 9 is a diagram illustrating an example of the time series data of the calculated direction code and distance. FIG. 10 is a diagram showing test data obtained by measurement and model data which is a model code. FIG. 11 is a flowchart illustrating an example of the operation of the sensor according to the first embodiment. FIG. 12 is a flowchart illustrating a first example of the behavior estimation process according to the first embodiment. FIG. 13 is a flowchart illustrating a second example of the behavior estimation process according to the first embodiment. FIG. 14 is a diagram illustrating an example of a front posture, a changeable posture, and a behavior in the behavior estimation unit according to the first embodiment. FIG. 15 is a flowchart illustrating a third example of the behavior estimation process according to the first embodiment. FIG. 16 is a flowchart illustrating another example of the operation of the sensor according to the first embodiment. FIG. 17 is a flowchart illustrating another example of the operation of the sensor according to the first embodiment. FIG. 18 is a flowchart illustrating another example of the operation of the sensor according to the first embodiment. FIG. 19 is a block diagram showing a functional configuration of a circuit and a memory according to the second embodiment. FIG. 20 is a flowchart illustrating an example of the operation of the sensor according to the second embodiment. FIG. 21 is a flowchart illustrating an example of an operation of the posture probability estimating unit according to Embodiment 2. FIG. 22 is a diagram illustrating an example of teacher data processing used for posture probability estimation according to the second embodiment. FIG. 23 is a diagram illustrating an example of normalization and posture estimation of teacher data obtained by posture probability estimation according to the second embodiment. FIG. 24 is a diagram illustrating an example of behavior probability estimation by the behavior probability estimation unit according to the second embodiment.

(Knowledge underlying the present invention)
The present inventors have conducted detailed studies on a conventional technique relating to situation estimation such as posture and behavior of a living body using a radio signal. As a result, the methods of Patent Documents 1 and 2 can detect the presence or absence of a person, but cannot detect the direction, position, size, posture, and the like of the person. all right.

  Further, it has been found that the method of Patent Document 3 has a problem that it is difficult to detect a direction in which a living body such as a person exists or a position where the living body exists in a short time and with high accuracy. This is because the frequency change due to the Doppler effect due to life activity is extremely small, and in order to observe this frequency change by Fourier transform, it is necessary to observe the body for a long time (for example, several tens of seconds) while standing still. is there. Further, in general, the living body rarely keeps the same posture or position for several tens of seconds.

  Further, Patent Document 4 discloses a device for estimating the presence / absence, rest, and activity of a person using a Doppler sensor, but has a problem that the posture of the user cannot be understood. Further, in Patent Document 5, although the posture of a person can be estimated using a sensor, there is a problem that it is not known whether the person is moving or operating. Patent Document 6 discloses a device for estimating the movement of a person or luggage using an electronic tag, a camera image, or the like. However, this technique has a problem of privacy because an image is taken.

  As a result of repeated studies on the above problems, the inventors have found that the propagation characteristics and the scattering cross section of the reflected signal transmitted from the transmission signal generator including the antenna elements placed at different positions and reflected by the living body ( 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 disclosure has been found that it is possible to estimate the state of a living body indicated by the behavior of the subject in a short time and with high accuracy, and thus has reached the present disclosure.

  That is, the sensor according to one embodiment of the present disclosure is a sensor, and includes N (N is a natural number of 3 or more) transmitting antenna elements that each transmit a transmission signal to a predetermined range where a living body can exist. A transmission signal generator, and N reception signals including reflected signals in which 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, a circuit, and a memory, wherein the circuit has a predetermined configuration in each of the M receiving antenna elements. From each of the N received signals received during the period, 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. And calculating a complex transfer function indicating a propagation characteristic between the transmitting antenna element and the receiving antenna element in the combination, and using the calculated N × M complex transfer function as a component. A first matrix calculator for sequentially calculating a matrix, and a second matrix corresponding to a predetermined frequency range in the first matrix sequentially calculated in the first matrix calculator are sequentially extracted, so that the respiration and heart rate of the living body are obtained. And a second matrix extraction unit for sequentially extracting the second matrix corresponding to a component affected by vital activity including at least one of body movement and whether a living body exists within the predetermined range by a predetermined method. The presence / absence determination unit that performs the presence / absence determination to determine whether the living body exists within the predetermined range, and the second presence / absence determination unit determines that the living body exists within the predetermined range, and then the second matrix extraction unit sequentially extracts the A position estimating unit for sequentially estimating a position of the living body with respect to the sensor using a matrix; (i) a position of the living body sequentially estimated by the position estimating unit; and a position of the transmission signal generator And, based on the position of the receiver, the first distance indicating the distance between the transmission signal generator and the position where the living body is sequentially estimated based on, and the distance between the living body and the receiver (Ii) a Doppler RCS calculator that sequentially calculates a Doppler RCS (Rader cross-section) value for the living body using the calculated first distance and the second distance. And storing the position of the living body, which is sequentially estimated, in the memory a predetermined number of times in the estimated order, and using the position of the living body stored in the memory, the predetermined number of times, to determine the presence of the living body. If the displacement of the position is greater than or equal to a predetermined value, the living body is determined to be moving, and if less than the predetermined value, the movement determining unit determines that the living body is not moving, and a predetermined method. A Doppler RCS threshold setting unit that sets a Doppler RCS threshold, 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 Doppler RCS threshold determination unit to be determined, a determination result in the movement determination unit, and an estimation of the posture of the living body and an estimation of the behavior of the living body according to at least one of the determination result in the Doppler RCS threshold determination unit And a situation estimating unit that selectively performs at least one of the following.

  For this reason, the movement of the living body, the posture of the living body, and the state of the living body, which is one of the behaviors of the living body, can be estimated in a short time and with high accuracy.

  Further, the situation estimation unit, when the movement determination unit determines that the living body is not moving, and when the Doppler RCS threshold determination unit determines that the Doppler RCS value is equal to or less than the Doppler RCS threshold The Doppler RCS threshold determination unit may estimate the posture of the living body, and estimate the behavior of the living body when the Doppler RCS value is determined to be larger than the Doppler RCS threshold.

  For this reason, 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, so that the posture of the living body can be accurately estimated. Further, when the Doppler RCS value is larger than the Doppler RCS threshold, it is determined that the living body is operating, and the behavior of the living body is estimated, so that the behavior of the living body can be accurately estimated.

  The situation estimation unit may determine that the behavior of the living body is moving when the movement determining unit determines that the living body is moving.

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

  Further, at least three transmitting antenna elements of the N transmitting antenna elements are respectively arranged at different positions in a vertical direction and a horizontal direction, and at least three receiving antenna elements of the M receiving antenna elements are arranged. Are respectively arranged at different positions in the vertical direction and the horizontal direction, and the memory has a Doppler RCS value, and a vertical position that is the position of the living body with respect to the sensor in the vertical direction, and the posture of the living body. And the position estimating unit estimates a three-dimensional position including a vertical position that is the position of the living body with respect to the sensor in the vertical direction as the position where the living body exists. The situation estimating unit stores the calculated Doppler RCS value, the vertical position, and the Above using the information indicating the correspondence relationship, the you are, may estimate the posture of the living body.

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

  Further, at least three transmitting antenna elements of the N transmitting antenna elements are respectively arranged at different positions in a vertical direction and a horizontal direction, and at least three receiving antenna elements of the M receiving antenna elements are arranged. Are respectively arranged at different positions in the vertical direction and the horizontal direction, and the memory has a Doppler RCS value, and a vertical position that is the position of the living body with respect to the sensor in the vertical direction, and the posture of the living body. And the position estimating unit estimates a three-dimensional position including a vertical position that is the position of the living body with respect to the sensor in the vertical direction as the position where the living body exists. The situation estimating unit may calculate the Doppler RCS value, the vertical position, and information indicating the correspondence. When, using the respective probability of the pose is the probability of one or more of the attitude in which the living body to a predetermined possible may be estimated as the posture of the living body.

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

  Further, the situation estimating unit, by using the sequentially calculated Doppler RCS value, and the sequentially estimated position of the living body, to sequentially estimate the posture of the living body, and then sequentially estimated 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. You 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, the sequentially calculated Doppler RCS value, and, after sequentially estimating the posture of the living body using the position where the living body is estimated sequentially, the posture of the living body sequentially estimated Before estimating the posture of the living body, wait until the sequentially calculated Doppler RCS value becomes equal to or less than the Doppler RCS threshold, and the 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 estimation is estimated as a rear posture, and the front posture which is the posture of the living body estimated last time stored in the memory, and the estimated posture is The behavior of the living body may be estimated using the rear posture.

  Therefore, the behavior of the living body can be estimated in a short time and with high accuracy.

  Further, the situation estimating unit, the sequentially calculated Doppler RCS value, and, after sequentially estimating the posture of the living body using the position where the living body is estimated sequentially, the posture of the living body sequentially estimated In the memory, and waits until the sequentially calculated 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, the last time stored in the memory Estimating one or more next actions of the living body using the estimated front posture that is the posture of the living body, using the Doppler RCS value sequentially calculated, and the position where the living body is estimated sequentially. The behavior of the living body may be estimated by specifying one behavior from the estimated one or more next behaviors.

  Therefore, the behavior of the living body can be estimated in a short time and with high accuracy.

  Further, the situation estimating unit, the sequentially calculated Doppler RCS value, and, after sequentially estimating the posture of the living body using the position where the living body is estimated sequentially, the posture of the living body sequentially estimated In the memory, and waits until the sequentially calculated 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, the last time stored in the memory Estimating one or more next actions of the living body using the estimated front posture that is the posture of the living body, using the Doppler RCS value sequentially calculated, and the position where the living body is estimated sequentially. An action probability, which is the probability of each of the estimated one or more next actions, may be estimated as the action of the living body.

  Therefore, the estimation of the action probability, which is the probability of each of the one or more next actions, can be performed 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.

  Further, the presence / absence determination unit estimates the number of living organisms present in the predetermined range, and when the number of living organisms is 0, determines that the living organism is not present in the predetermined range, When the number of persons is one or more, it may be determined that the living body exists in the predetermined range.

  For this reason, it is possible to determine whether or not the living body exists in the predetermined range by using the estimation of the number of living bodies existing in the predetermined range. Thus, the number of persons can be estimated at the same time as the estimation of the state of the living body.

  An estimation device according to another embodiment 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 where a living body can exist. Some of the N transmission signals transmitted by the transmission signal generator having N (N is a natural number of 3 or more) transmission antenna elements are reflected or scattered by the living body. The received N received signals are received from a receiver having M (M is a natural number of 3 or more) receiving antennas respectively received by the N receiving signals for a predetermined period in each of the M receiving antenna elements. An acquisition unit that acquires the number of received signals, and from each of the acquired N received signals, an N × combination of the N transmission antenna elements and the M reception antenna elements in a one-to-one correspondence. Set of M For each of the combinations, a complex transfer function indicating a propagation characteristic 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 calculation unit for sequentially calculating the first matrix of the first matrix, and a second matrix corresponding to a predetermined frequency range in the first matrix sequentially calculated in the first matrix calculation unit. A second matrix extraction unit for sequentially extracting the second matrix corresponding to a component affected by vital activity including at least one of respiration, heartbeat, and body movement; and a living body within the predetermined range by a predetermined method. A presence / absence determination unit for performing presence / absence determination for determining whether or not to perform, and after the presence / absence determination unit determines that a living body exists within the predetermined range, the second matrix extraction unit sequentially performs A position estimating unit for sequentially estimating a position of the living body with respect to the transmission signal generator and the receiver using the second matrix, and (i) the living body sequentially estimated by the position estimating unit. A first distance indicating the distance between the living body and the transmission signal generator, based on the position where the living body is located, the position of the transmission signal generator, and the position of the receiver, and the living body and the reception A second distance indicating the distance to the aircraft, and (ii) sequentially calculating a Doppler RCS (Rader cross-section) value for the living body using the calculated first distance and the second distance. Doppler RCS calculation unit, and sequentially stores the position of the living body that has been sequentially estimated in the estimated number of times in the memory in the estimated order, using the position where the living body is stored in the memory the predetermined number of times, A movement determining unit that determines that the living body is moving when the displacement of the position where the body is present is equal to or more than a predetermined value, and that determines that the living body is not moving when the displacement is less than the predetermined value; Comparing the calculated Doppler RCS value with the set Doppler RCS threshold value, and determining whether the Doppler RCS value is equal to or less than the Doppler RCS threshold value. Doppler RCS threshold determination unit for determining whether or not, the determination result in the movement determination unit, and at least one of the determination results in the Doppler RCS threshold determination unit, estimation of the posture of the living body, and A situation estimating unit for selectively performing one of the behavior estimation.

  For this reason, the movement of the living body, the posture of the living body, and the state of the living body, which is one of the behaviors of the living body, can be estimated in a short time and with high accuracy.

  It should be noted that the present disclosure is not only realized as a sensor, but also as an integrated circuit including a processing unit provided in such a sensor, or as a method in which the processing unit configuring the device is performed as a step. Can be realized as a program to be executed by a computer, or can be realized as information, data or a signal indicating the program. These programs, information, data, and signals may be distributed via a recording medium such as a CD-ROM or a communication medium such as the Internet.

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

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

  As shown in FIG. 1, the sensor 10 includes a transmission signal generator 20, a receiver 30, and an estimation device 100. The estimation device 100 includes a circuit 40 and a memory 41. The sensor 10 emits a microwave from the transmission signal generator 20 to a living body 50 such as a human, and receives a reflected wave 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. Transmit signal generator 20, lined _{N x} pieces in the horizontal direction (x-direction), and, _{N z} pieces are rectangular arranged side by side in the vertical direction (z-direction), N pieces _(N = N _x × N _z ) has an array antenna composed of the transmission antenna element 21 of FIG. That is, at least three of the N transmission antenna elements 21 are arranged at different positions in the vertical and horizontal directions.

The receiver 30 has M (M is a natural number of 3 or more) receiving antenna elements 31. Receiver 30, lined _{M x} pieces in the horizontal direction (x-direction), and vertical _{M z} number in (z direction) is rectangular arranged side by side, M pieces _{(M = M x × M z} ) Has an array antenna composed of the receiving antenna elements 31 of FIG. That is, at least three of the M receiving antenna elements 31 are arranged at different positions in the vertical and horizontal directions.

Here, an angle between a first reference direction that is a direction on the horizontal plane arbitrarily set with respect to the transmission signal generator 20 and a first living body direction that is a direction from the transmission signal generator 20 to the living body 50 is defined as: and φ _T. Further, the vertical direction, the elevation of the living body 50 is to angle for the first biological direction and theta _T. In addition, the elevation angle of the living body 50 which is an angle between a second reference direction which is a direction on the horizontal plane arbitrarily set with respect to the receiver 30 and a second living body direction which is a direction from the receiver 30 to the living body 50. It is referred to as φ _R. Further, the vertical direction, the angle between the second living direction and theta _R. The center coordinates of the site where the biological 50 is performing a vital activities _{(x b, y b, z} b) When, by the positional relationship of the transmission signal generator 20, receiver 30 and the biometric 50, the direction (theta _T, theta _{R, φ T, φ R)} and the coordinates _{(x b, y b, z} b) can be converted to each other.

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

  Specifically, each of the N transmitting antenna elements 21 emits a microwave as a transmission signal to a living body 50 such as a human. The N transmission antenna elements 21 may transmit a signal on which modulation processing different for each transmission antenna element 21 has been performed as a transmission signal. Further, each of the N transmitting antenna elements 21 may sequentially switch a modulated signal or a non-modulated signal and transmit the signal. The modulation process may be performed by the transmission signal generator 20. As described above, 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 signal transmitted by the receiver 30 is transmitted. The antenna element 21 can be specified. As described above, the transmission signal generator 20 may include a circuit for performing the modulation process.

  Each of the M receiving antenna elements 31 includes N received signals including a reflected signal that is a signal reflected or scattered by the living body 50 among the N transmitted signals transmitted by the N fixed transmitting antenna elements 21. To receive. The receiver 30 converts the frequency of a received signal composed of microwaves and converts it into a low-frequency signal. The receiver 30 outputs a signal obtained by converting the low frequency signal to a circuit 40. That is, the receiver 30 may include a circuit for processing the received signal.

  The circuit 40 performs various processes for operating the sensor 10. The circuit 40 includes, 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, a 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 may be a circuit that performs hardware processing.

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

  Next, a functional configuration of the circuit 40 will be described with reference to FIG.

  FIG. 2 is a block diagram showing a functional configuration realized by the circuit and the memory according to the first embodiment.

  The circuit 40 includes a first matrix calculation unit 410, a second matrix extraction unit 420, a number estimation unit 430, a position estimation unit 440, a Doppler RCS calculation unit 450, a movement determination unit 460, and a Doppler RCS threshold setting unit. 470, a Doppler RCS threshold determination unit 480, and a situation estimation unit 520.

  First matrix calculation section 410 calculates a complex transfer function from the received signal converted into a low-frequency signal. The complex transfer function represents the propagation loss and phase rotation between each transmitting antenna element 21 and each receiving antenna element 31. When the number of transmitting antenna elements is N and the number of receiving antenna elements is M, the complex transfer function is a complex matrix having M × N components. Hereinafter, this complex matrix is referred to as a complex transfer function matrix. The estimated complex transfer function matrix is output to second matrix extraction section 420. In other words, the first matrix calculation unit 410 calculates N transmission antenna elements 21 and M reception antenna elements from each of the plurality of reception signals received in each of the M reception antenna elements 31 in the predetermined period. Then, an N × M first matrix having the complex transfer functions indicating the propagation characteristics between the first and the second matrices 31 as components is sequentially calculated. The propagation characteristic between each of the N transmitting antenna elements 21 and each of the M receiving antenna elements 31 is such that the N transmitting antenna elements 21 and the M receiving antenna elements 31 have a one-to-one correspondence. 9 shows propagation characteristics between the transmitting antenna element 21 and the receiving antenna element 31 in each of the N × M combinations.

  The second matrix extraction unit 420 separates a complex transfer function matrix component obtained from a received signal passing through the living body 50 into a complex transfer function matrix component obtained from a received signal not passing through the living body 50. The component that has passed through the living body 50 is a component that fluctuates over time due to life activity. Therefore, the components passing through the living body 50 are, for example, components other than the direct current from the components obtained by performing Fourier transform on the components of the complex transfer function matrix in the time direction when the components other than the living body 50 are stationary. Can be extracted by taking out Further, the components that have passed through the living body 50 can be extracted, for example, by extracting a component whose difference from the result observed when the living body 50 is not within the predetermined range exceeds a predetermined threshold. As described above, the second matrix extraction unit 420 extracts the complex transfer function matrix component obtained from the received signal including the reflected signal that has passed through the living body 50, and uses the extracted complex transfer function matrix component as the second matrix. calculate. In other words, 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, and thereby detects the respiration, heartbeat, and body motion of the living body. A second matrix corresponding to a component affected by the vital activity including at least one of them is sequentially extracted.

  The predetermined frequency range is, for example, a frequency derived from vital activity including at least one of the above-described respiration, heartbeat, and body motion of a living body. The predetermined frequency range is, for example, a frequency in a range from 0.1 Hz to 3 Hz. The second matrix extraction unit 420 extracts a second matrix corresponding to the above-mentioned predetermined frequency range, thereby obtaining a heart activity, a lung activity, a diaphragm, a vital activity of a part of the living body 50 due to a built-in movement, or a hand, a foot, or the like. Biological components affected by vital activity can be extracted. The part of the living body 50 due to the heart, lung, diaphragm, and built-in movement is, for example, a person's soul.

  Here, the second matrix extracted by the second matrix extraction unit 420 is a matrix having N × M components, and is extracted from a complex transfer function obtained from a received signal observed in the receiver 30 during a predetermined period. You. Therefore, it is assumed that the second matrix has frequency response or time response information. Note that the predetermined period is a period that is substantially half of at least one cycle of the respiration, heartbeat, and body movement of the living body.

  The second matrix calculated by second matrix extraction section 420 is output to number estimation section 430. The number estimation unit 430 estimates the number of persons using an eigenvalue or an eigenvector 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, for example. May be performed. The number estimation unit 430 is an example of a presence / absence determination unit that determines whether a living body exists within a predetermined range. The number estimating unit 430 estimates the number of living organisms existing in the predetermined range, and when the estimated number of living organisms is 0, determines that no living organism exists in the predetermined range. In the case described above, it may be determined that the living body exists in the predetermined range.

The position estimating unit 440 uses the second matrices sequentially extracted by the second matrix extracting unit 420 after the number estimating unit 430 determines that the living organisms exist within the predetermined range, and Estimate the position to perform. The position estimating unit 440 estimates both the angle of departure θ _T from the transmission signal generator 20 and the angle of arrival θ _R to the receiver 30, and calculates a triangle based on the estimated departure angle θ _T and angle of arrival θ _R. The position of the living body 50 is estimated by using the method. The position of the living body 50 estimated here is 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 10. The position of the living body 50 sequentially estimated by the position estimating unit 440 may be stored in the memory 41.

  The Doppler RCS calculating section 450 sequentially calculates a Doppler scattering cross section (Doppler RCS: Radar Cross Section) value using the sequentially extracted second matrix and the sequentially estimated position. The Doppler RCS calculator 450 specifically calculates the position sequentially estimated by the position estimator 440, the position of the transmission signal generator 20, and the position of the receiver 30, in order to calculate the Doppler RCS value. Based on the distance RT indicating the first distance, which is the distance between the position where the living body 50 is estimated sequentially and the transmission signal generator 20, and the position between the sequentially estimated living body 50 and the receiver 30. The distance RR indicating the second distance, which is the distance, is sequentially calculated. The Doppler RCS calculation section 450 calculates a propagation distance from the sequentially calculated distance RT and distance RR, and sequentially calculates a Doppler RCS value using the calculated propagation distance and the strength 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 determination unit 460 stores the position where the living body 50 is sequentially estimated by the position estimation unit 440 in the memory 41 in the order in which the living body 50 is estimated. The movement determination unit 460 determines whether the living body 50 is moving using the position 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 for a predetermined time period, for example, the past 5 seconds, from the plurality of stored positions of the living body 50, and refers to the latest position and the immediately preceding position. The distance between the positions, the distance between the previous position and the previous position,..., And the distance between the L-1 previous position and the L previous position Then, the sum of all the calculated L-1 distances is calculated as the moving distance. That is, the movement determination unit 460 calculates the movement distance by using all the L positions sampled in the predetermined time and integrating the distance between the two temporally adjacent positions. In addition, it can be said that the moving distance is a change in the position where the living body 50 exists.

  Then, for example, when the calculated movement distance is equal to or more than a predetermined value such as 1 m, the movement determination unit 460 determines that the living body 50 is moving during the predetermined time of the past 5 seconds. If the calculated movement distance is less than the predetermined value, the movement determination unit 460 determines that the living body has not moved during the predetermined time.

  Note that the movement determination unit 460 calculates the movement distance using all of the plurality of positions sampled in the predetermined time, but is not limited thereto, and calculates the distance between the latest position and the position before the predetermined time. It may be calculated as a moving distance, or may extract several points among L positions for a predetermined time and integrate the distance between two temporally adjacent points among the extracted several points. May be used to calculate the moving distance.

  Doppler RCS threshold setting section 470 sets a Doppler RCS threshold by a predetermined method. Specifically, the Doppler RCS threshold setting unit 470 sets the Doppler RCS threshold according to the state of the living body 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 living body situations may be set. For example, as shown in FIG. 3, ten Doppler RCSs in a certain front posture calculated up to ten times in the past as shown in FIG. A value obtained by multiplying the average of the values by a fixed ratio such as 1.5 times (150%) may be set as the threshold. FIG. 3 is a diagram illustrating a Doppler RCS threshold value set value table in the sensor according to the first embodiment.

  At this time, since the optimal value of the ratio by which the threshold value is multiplied differs depending on the front posture of the application destination, the ratio may be appropriately determined for each front posture of the application destination. For example, the ratio for calculating the Doppler RCS threshold when the lowermost front posture in FIG. 3 is in the supine position and the next posture is turning over is 1.1 times (110%), and in other cases the Doppler RCS threshold is May be 1.2 times (120%). This is because the Doppler RCS value calculated when the lowermost front posture is in the lying position and the next posture is turning over is a smaller value 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. It is determined whether or not.

  The situation estimation unit 520 is one of the posture of the living body 50 and the action of the living body 50 according to at least one of the determination result of the movement determination unit 460 and the determination result of the Doppler RCS threshold determination unit 480. Estimate the state of the living body. The situation estimation unit 520 includes a posture estimation unit 490 and a behavior estimation unit 500.

  The posture estimating unit 490 determines the posture of the living body 50 when the movement determining unit 460 determines that the living body 50 is not moving, and when the Doppler RCS threshold determining unit determines that the Doppler RCS value is equal to or smaller than the Doppler RCS threshold. Is estimated. In this case, the posture estimating unit 490 can estimate that the position of the living body 50 has hardly changed, and can estimate that the posture of the living body 50 is not moving. Can be estimated. The posture estimating unit 490 calculates the Doppler RCS value calculated by the Doppler RCS calculating unit 450, the vertical position of the living body 50, and the Doppler RCS value stored in the memory 41, for example, using the method described in Patent Document 5. The posture of the living body 50 is estimated using the information 42 indicating the correspondence between the vertical position of the living body 50 and the posture of the living body 50.

  In Patent Document 5, the posture 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 associated with the teacher data closest to the vertical position of the living body and the Doppler RCS value may be estimated as the posture of the living body 50. FIG. 4 is a diagram illustrating an example of posture estimation by the posture estimating unit according to the first embodiment.

  When the Doppler RCS threshold determining unit 480 determines that the Doppler RCS value is larger than the Doppler RCS threshold, the behavior estimating unit 500 estimates the behavior of the living body 50. In this case, since the behavior estimation unit 500 can estimate that the posture of the living body 50 is moving, the behavior of the living body 50 can be estimated. The behavior 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 Doppler RCS value and the transition vector of the vertical position of the living body 50 in advance. The behavior of the living body 50 is estimated by calculating the correlation with the learned teacher vector.

  FIG. 5 is a block diagram illustrating an example of a configuration of the behavior estimation unit 500 according to Embodiment 1.

  The behavior estimating unit 500 includes time-series data indicating a temporal change in the position estimated by the position estimating unit 440 and the Doppler RCS value calculated by the Doppler RCS calculating unit 450, and a 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 behavior estimation unit 500 includes an operation period extraction unit 510, a direction code calculation unit 511, and an operation comparison unit 512.

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

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

  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 is not necessarily provided. That is, when posture estimation is performed for all sections, it goes without saying that the operation period extraction unit 510 may be omitted and estimation may be performed for all sections.

  The direction code calculation unit 511 is a temporal change in the operation period extracted by the operation period extraction unit 510, and is a vertical position (height position) obtained from the estimated position of the living body 50, and the calculated Doppler. The temporal change of the RCS value is converted into a direction 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. 7, and in a trajectory in the time change, the distance ΔP of the trajectory and the direction of the trajectory. is calculated. The direction code calculation unit 511, for example, calculates the height position H1 at the first timing and the first coordinates p1 (H1, R1) indicated by the Doppler RCS value R1 at the second timing following 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) A distance ΔP between the first coordinate p1 (H1, R1) and a direction θ when the second coordinate p2 (H2, R2) is viewed from the first coordinate p1 (H1, R1) is calculated to convert the vector into a direction vector. FIG. 7 is a diagram for explaining a 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 calculation unit 511 specifies a direction code having the closest direction θ among the direction codes indicated by 1 to 8. FIG. 8 is a diagram illustrating an example of the direction code table.

  The direction code calculation unit 511 calculates the direction code and the distance ΔP as described above to obtain time-series data of the direction code as shown in FIG. FIG. 9 is a diagram illustrating an example of the time series data of the calculated direction code and distance. At this time, the direction code calculation unit 511 may perform normalization of the direction code in order to avoid the influence of the individual difference.

  The operation comparing unit 512 compares the time-series data of the direction code calculated by the direction code calculating unit 511 with the information 42 indicating the corresponding state stored in the memory, and thereby determines the corresponding information 42 indicating the corresponding state. The behavior of the living body 50 is estimated by specifying the behavior associated with the time-series data.

  The information 42 indicating the correspondence status stored in the memory 41 includes a vertical position, which is a position in the vertical direction where the living body 50 exists with respect to the sensor 10, and a plurality of model codes indicating a temporal change of the Doppler RCS value; This is information indicating the state of correspondence with the behavior of the living body 50. In addition, the behavior of the living body 50 associated in the information 42 indicating the correspondence status includes a fall, a sitting on a chair, a sitting on a floor, a standing from a chair, a standing from the floor, a jump, and a direction change. . That is, the behavior estimating unit 500 indicates the position estimated by the position estimating unit 440, the temporal change of the Doppler RCS value calculated by the Doppler RCS calculating unit 450, and the corresponding state stored in the memory 41 in advance. Using the information 42, it is estimated whether the living body 50 has performed any of the following actions: falling, sitting on a chair, sitting on the floor, standing from a chair, standing from the floor, jumping, and turning. . The model code is represented 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 determining unit 460 determines that the living body 50 is moving. In this case, the behavior estimation unit 500 may estimate the behavior of the living body 50 to be walking when the posture of the living body 50 estimated immediately before it is determined that the living body 50 is moving is standing. . In addition, when the posture of the living body 50 estimated immediately before the living body 50 is determined to be moving is the sitting position, the behavior estimation unit 500 may estimate the behavior of the living body 50 to be movement by a wheelchair. . In addition, when the posture of the living body 50 estimated immediately before the living body 50 is determined to be moving is in the lying position, the behavior estimating unit 500 estimates that the behavior of the living body 50 is turning over or crawling. You may.

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

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 operation principle of the sensor 10 according to the first embodiment will be described using mathematical expressions. Here, a method of extracting a biological component using Fourier transform will be described. The processing described here is performed by the circuit 40. The complex transfer function matrix between the transmission signal generator 20 and the receiver 30 is

Is defined. Here, t represents time. When each component of Equation 1 is Fourier transformed,

The following frequency response matrix is obtained. Here, f represents a frequency, and each component of the frequency response matrix is a complex number. This frequency response matrix includes both a propagation component passing through the living body 50 and a propagation component passing through other than the living body 50. When it is considered that the body other than the living body is stationary, it is considered that the DC component of the frequency response matrix, that is, G (0) mainly includes a propagation component other than the living body. This is because a Doppler shift occurs due to a vital activity including at least one of respiration, heartbeat, and body motion of a living body, and it is considered that components passing through the living body are included in other than f = 0. Furthermore, considering the frequency of the respiration or heartbeat of the 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, for example, if G (f) in a predetermined frequency range of 0 [Hz] <f <3 [Hz] is extracted, a 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 living body position estimation method using the living body component G (f) will be described. The biological component matrix G (f) is

Sort into 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),

Calculate by Here, ｛·｝ ^H represents a complex conjugate transpose. Further, R is averaged between 0 [Hz] <f <3 [Hz]. It is known that this averaging improves the position estimation accuracy described later. Then, the calculated correlation matrix R by eigenvalue decomposition to calculate the eigenvector U and its complex conjugate transposed vector U ^H of the correlation matrix R.

  Note that the eigenvector in Expression 5 is expressed by Expression 6 shown 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, ui 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,

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

It is expressed as here,

It is expressed as Here, k represents a wave number, d _Tx and d _Tz represent element intervals in the x direction and z direction of the transmitting antenna element 21, respectively, and d _Rx and d _Rz represent x in the x direction and z direction of the receiving antenna element 31, respectively. Indicates the element spacing. In the present embodiment, it is assumed that the linear array antenna is constant in the direction in which the element spacing is the same.

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。 d _Tx represents, for example, an interval between two transmission antenna elements 21 adjacent to each other in the x direction among the plurality of transmission antenna elements 21. d _Tz represents, for example, an interval between two transmission antenna elements 21 adjacent to each other in the z direction among the plurality of transmission antenna elements 21. D _Rx represents, for example, an interval between two reception antenna elements 31 adjacent to each other in the x direction among the plurality of reception antenna elements 31. D _Rz represents, for example, an interval between two reception antenna elements 31 adjacent to each other in the z direction among the plurality of reception antenna elements 31. When calculating the Kronecker product of these steering vectors,

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

The body position is specified by Here, the evaluation function of Expression 11 is called a MUSIC spectrum, and a search is made for a maximum point in a combination (θ _T , θ _R ) of a direction from each of the transmission signal generator 20 and the receiver 30 to the detection target. Thus, the three-dimensional position of the living body 50 as viewed from the transmission signal generator 20 and the receiver 30, including the vertical position, can be specified from θ _T and θ _R corresponding to the maximum, using trigonometry.

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。 Further, the Doppler RCS value is obtained from Expression 12, and the posture of the living body 50 is estimated based on 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), a power transfer coefficient is obtained from a channel component reflected and observed from a living body.

Can be calculated. Where ρij is a matrix

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

It is expressed as Here, Pt represents transmission power. It is assumed that equal power is transmitted from all transmission antenna elements 21. Gt represents the operation gain of the transmission signal generator 20, Gr represents the operation 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 the distance. The distance R1 and the distance R2 can be easily calculated from the position estimated by Expression 13. Then, since the power transfer coefficient defined by Equation 12 is expressed by ρij = Prij / Pt, the scattering cross section is

Can be calculated by Note that the scattering cross section handled here is not the scattering cross section of the whole living body 50 but the Doppler scattering area corresponding to the fluctuation 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 all elements,

To determine the average scattering cross section. Or later,

Is called Doppler RCS.

  Note that, for example, when the vital component and the body motion component of the living body are further separated and measured, it is needless to say that the frequency range of Expression 14 may be adjusted and the subsequent processing may be performed.

  The method for estimating the behavior will be described below.

  When the Doppler RCS value σ and the height z of the living body 50 are continuously estimated 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, there is almost no change in the Doppler RCS value. Therefore, when the living body is behaving, that is, a flow of a locus point having a large fluctuation of the Doppler RCS value is extracted. With respect to this locus point group, a locus point movement amount, which is the distance between the (i-1) th locus point and the i-th locus point, is defined as ΔPi, and the i-1 th locus point and the i-th locus point The angle between them is defined as an angle parameter αi, and is defined as Expression 20 and Expression 21, respectively.

Next, a direction code is assigned to the moving direction of the locus point using the value of the angle parameter. Assignment of a direction code to an angle divides 360 ° into eight, and assigns numbers 1 to 8 to each direction. At this time, the boundaries of the codes may not be provided in the vertical and horizontal directions so that the codes do not frequently change when moving in the vertical and horizontal directions. Since there is an individual difference in the operation speed in the action of the living body 50, the difference in the operation speed is considered in order to avoid erroneous recognition due to the difference in the number of trajectory points depending on the operation speed even for the same operation. The normalized direction code may be normalized. For example, from the original direction code sequence c _j (j = 1 to j _max ) obtained by the direction estimation, a normalized code sequence consisting of K terms is considered in consideration of the ratio of the trajectory point movement amount to the total sum of the trajectory point movement amounts. Generate Here, j _max is the number of trajectory points, which differs depending on the operation time. The normalized code sequence C _k (k = 1, 2,..., K) is created from the i-th trajectory movement amount ΔPi and the total _sum of the trajectory point movement amounts ΔP _{sum as} follows.

  1) When j = 1, the normalized code sequence in the range of k that satisfies Expression 22 is the code of j = 1 in the original direction code sequence.

2) When j is in the range of 2 to j _max , the normalized code sequence in the range of k that satisfies the following equation 23 is a code at each j. However, ΔP _sum satisfies _Equation 24.

The behavior of the living body 50 is estimated by comparing a normalized number 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. The sequence of model data is measured a plurality of times in advance while performing each of a plurality of actions in advance, and the most directional code in each item of the normalized code string obtained by measuring the actions multiple times is The model data for that term. Since the direction codes are annular, the maximum difference is four. Equation 25 is used to calculate the actual difference between the direction code number. However, when δC _i > 4, Equation 26 is used.

Here, C _{test, i} indicates the element of the _i-th term of the test data string, and C _{model, i} indicates the element of the _i-th term of the model data string. Next, the sum of squares of the difference between the direction codes of the test data and the model data is calculated as a deviation represented by Expression 27. For example, as shown in FIG. 12, by comparing the test data with the model data, the behavior determination deviation E is calculated by Expression 27. FIG. 12 is a diagram showing test data obtained by measurement and model data which is a model code.

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

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

  FIG. 11 is a flowchart illustrating an example of the operation of the sensor according to the first embodiment.

  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 in a predetermined range where the living body 50 can exist.

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

  The circuit 40 is configured to determine between each of the N transmission antenna elements 21 and each of the M reception antenna elements 31 from each of the N reception signals received in each of the M reception antenna elements 31 during a predetermined period. The first matrix of N × M is sequentially calculated with each complex transfer function indicating the propagation characteristic of the component as a component (S11).

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

  The circuit 40 uses the first matrix or the second matrix to perform the presence / absence determination for determining whether the living body 50 exists within a predetermined range as the effective range of the sensor 10 (S13). In step S13, a number estimation for estimating the number of living organisms existing in the predetermined range may be performed. 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), It returns 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 positions of the living body 50 in the memory 41 a predetermined number of times in the estimated order.

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

  The circuit 40 determines whether the displacement of the position where the living body 50 is present is less than a predetermined value using the position where the living body 50 is present stored in the memory 41 a predetermined number of times (S16). The circuit 40 determines that the living body 50 is moving, for example, when the movement amount is 1 m or more in 5 seconds (No in S16), and returns to step S11. The behavior of the living body 50 may be determined to be moving by using this result. For example, if the movement amount 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 times stored in the memory 41 and sets a 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 posture, or may be obtained by multiplying the average value of the past Doppler RCS values by a predetermined ratio, for example, 1.5 times. A value may be set.

  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 (S18).

  When the calculated Doppler RCS value is equal to or smaller than the Doppler RCS threshold (Yes in S18), the circuit 40 performs a posture estimation process of 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 a behavior estimation process of estimating the behavior of the living body 50 by the behavior estimation unit 500 (S20).

  A specific example of the processing in the circuit 40 has already been described in the description of the functional configuration of the circuit 40, and a description thereof will be 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 in accordance with at least one of the determination result in the movement determination and the determination result in the Doppler RCS threshold value determination. At least one is selectively performed.

  FIG. 12 is a flowchart illustrating a first example of the details of the behavior estimation process.

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

  The circuit 40 converts the temporal change in the extracted operation period, that is, the vertical position obtained from the estimated position, and the temporal change in the calculated Doppler RCS value into a direction vector 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 correspondence status stored in the memory, and thereby associates the time-series data with the information 42 indicating the correspondence status. The behavior of the living body 50 is estimated by specifying the behavior (S23).

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

  The circuit 40 receives an input for designating a predetermined operation by 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, processing similar to steps S11 to S22 and steps S21 and S22 of the operation of the sensor 10 described above is sequentially performed.

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

  According to the sensor 10 according to the present embodiment, the estimation of the posture of the living body 50 and the estimation of the behavior of the living body 50 are performed in accordance with at least one of the determination result in the movement determination and the determination result in the Doppler RCS threshold determination. At least one is selectively performed. Therefore, the movement of the living body 50, the posture of the living body 50, and the state of the living body which is one of the actions 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, it is possible to accurately estimate a position where the living body 50 exists and the presence / absence, stillness, movement, posture, and behavior of the living body at the position in a short time and with high accuracy.

  The sensor 10 detects the presence of the living body 50 by detecting a moving part. Therefore, for example, by using this, it is possible to estimate whether the human is alive and in any of the postures of upright, chair, cross, and supine. As a result, the survival of the human can be confirmed effectively. In addition, since the existence of a human can be confirmed without analyzing the image captured by the camera, the existence of a human can be confirmed while protecting the privacy of the human.

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

  FIG. 13 is a flowchart illustrating a second example of the behavior estimation process according to the first embodiment.

  The attitude estimating unit 490 of the circuit 40 stores the estimated attitude in the memory 41 every time the attitude is estimated.

  The behavior estimation unit 500 refers to the latest posture of the living body 50 stored in the memory 41 and acquires the latest posture as a front posture used for estimating the behavior of the living body 50 (S31).

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

  The behavior estimation unit 500 determines whether or not 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 smaller than the Doppler RCS threshold (Yes in S33), the behavior estimating unit 500 causes the posture estimating unit 490 to estimate the posture of the living body 50, and the estimated posture to the rear posture in the behavior. (S34). That is, the behavior estimating unit 500 waits until the living body 50 stops by waiting until the Doppler RCS value becomes equal to or less than the Doppler RCS threshold, and N received signals when 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 rear posture. The behavior estimating unit 500 can acquire an accurate rear posture by acquiring the posture after the living body 50 has stopped as the rear posture.

  Thereafter, the behavior estimating unit 500 estimates the behavior of the living body 50 using the acquired front posture and the estimated rear posture (S35). For example, the action estimating unit 500 refers to the correspondence state in which the front posture, the rear posture, and the behavior shown in the table illustrated in FIG. 14 are associated with each other, and corresponds to the combination of the front posture and the rear posture in the correspondence state. By specifying the attached behavior, the behavior of the living body 50 is estimated. FIG. 14 is a diagram illustrating an example of a correspondence state between a combination of a front posture and a rear posture and a behavior in another example of the behavior estimation processing according to the first embodiment.

(Modification 2 of Embodiment 1)
Further, for example, as shown in FIG. 14, the behavior estimating unit 500 limits the rear posture, which is the posture after the generated behavior, by the front posture, so that when the front posture is specified, It is possible to narrow down the options for possible actions. 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 behavior may be estimated by separating the action options that occur after the specified front posture.

  FIG. 15 is a flowchart illustrating a third example of the behavior estimation process according to the first embodiment.

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

  The behavior estimating unit 500 performs steps S42 and S43. Steps S42 and S43 are the same as steps S32 and S33, respectively, and will not be described.

  Since the acquired front posture is standing in step S44, the behavior estimation unit 500 refers to the corresponding situation in FIG. 14 to narrow down to the next rear posture being the lying position or the sitting position. The behavior is estimated (S44). Specifically, the posture estimating unit 490 for estimating the rear posture next estimates the posture having the closest estimation result among the sitting position and the lying position as the rear posture. For example, by comparing teacher data of the sitting position and the lying position with a combination of the vertical position and the Doppler RCS value of the living body 50, one of the sitting position and the lying position is estimated as the rear posture of the living body 50.

  Similarly, when the front posture is posture B, the behavior estimation unit 500 proceeds to step S45. In steps S45 to S47, the processing itself is the same as steps S42 to S44, except that the front posture is different, and a description thereof will be omitted.

(Modification 3 of Embodiment 1)
Note that the flowchart showing the operation of the sensor 10 shown in the first embodiment is an example, and as shown in FIGS. 16 and 17, the first matrix and the second matrix, positional information of the living body 50, Doppler RCS, and the like. By storing the data in the memory 41, the post-processing can be shared between the server and another computer, and the Doppler RCS threshold can be determined first as shown in FIG.

  FIG. 16 is a flowchart illustrating another example of the operation of the sensor according to the first embodiment.

  As illustrated in FIG. 16, the circuit 40 of the sensor 10 may perform the processes of steps S11 to S15 and the processes of steps S16 to S20 in the flowchart described in FIG. 11 separately. That is, the first device that performs the processing of steps S11 to S15 may be different from the second device that performs the processing of steps S16 to S20.

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

  Next, the second device reads the latest result from the memory (S102). Then, the second device executes the processing of steps S16 to S20.

  Each of the first device and the second device includes a circuit and a memory.

  FIG. 17 is a flowchart illustrating another example of the operation of the sensor according to the first embodiment.

  As shown in FIG. 17, the circuit 40 of the sensor 10 may perform the processes of steps S11 to S19 and the process of step S20 in the flowchart described in FIG. 11 separately. That is, the third device that performs the processing of steps S11 to S19 may be different from the fourth device that performs the processing of step S20.

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

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

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

  When the Doppler RCS value is larger 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 smaller than the Doppler RCS threshold (Yes in S114), the process returns to step S112.

  FIG. 18 is a flowchart illustrating another example of the operation of the sensor according to the first embodiment.

  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 before the determination of whether or not the living body 50 is moving.

  In this case, similarly to step S17, the circuit 40 refers to the previous posture and the average value of the Doppler RCS values for a predetermined number of times in the past 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 smaller than the Doppler RCS threshold (Yes in S122), the circuit 40 performs a posture estimation process of estimating the posture of the living body 50 by the posture estimating unit 490 (S19), and returns to step S11. .

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

  If the movement amount is larger than the threshold value (No in S16), the circuit 40 determines that the vehicle is moving, and returns to step S11.

(Embodiment 2)
In the circuit 40 according to the first embodiment, one posture or one behavior of the living body 50 at a certain timing is estimated. However, the present invention is not limited to this. May be estimated. The posture probability of the living body 50 is a probability that it is estimated that each of one or more predetermined postures that the living body 50 can take has occurred. The behavior probability of the living body 50 is a probability that it is estimated that each of one or more predetermined actions that the living body 50 can take has occurred.

  FIG. 19 is a block diagram showing a functional configuration of a circuit and a memory according to the second embodiment.

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

  FIG. 20 is a flowchart illustrating an example of the operation of the sensor according to the second embodiment.

  Embodiment 2 is different from Embodiment 2 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 a posture probability estimation process in the posture probability estimation unit. FIG. 22 is a diagram illustrating an example of teacher data used for posture probability estimation according to the second embodiment.

  The posture probability estimating unit 491 first normalizes teacher data for estimating a posture (S51). The posture probability estimating unit 491 may execute step S51 each time the teacher data is updated. In the normalization of the teacher data, for example, as shown in FIG. 22, in order to suppress variations in the height direction in the original teacher data, for example, 70% or more and 30% or less of the teacher data of each posture Remove. The range of the data to be set, which is set at this time, differs depending on the installation status and use of the sensor 10A. Next, height information and Doppler RCS information are normalized using Expressions 27 and 28.

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

  In FIG. 23, when, for example, the measurement data is located at the star in FIG. 23, the posture probability estimating unit 491 extracts, for example, data of 100 points near the star and performs posture probability estimation (S52). For example, when 70 points out of the extracted 100 points indicate a standing position and 30 points indicate a sitting position, the posture probability estimating unit 491 calculates a posture probability estimated value including 70% in the standing position and 30% in the sitting position. It is calculated as the posture of the living body 50.

  Next, FIG. 24 is a flowchart illustrating an example of the behavior probability estimation process in the behavior probability estimation unit.

  In the second embodiment, as described with reference to FIGS. 21 to 23 above, the posture probability estimation value is calculated by the posture probability estimation unit 491, and the calculated posture probability estimation value is sequentially stored in the memory 41. .

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

The action probability estimating unit 501 calculates a probability of a possible action for each of the plurality of initial poses. For example, in step S61, the posture probability of initial posture A was estimated to be P _a1, attitude probability of initial posture B is estimated to P _b1, attitude probability of initial posture C is estimated to be P _c1, the posture of the initial position D It is assumed that the probability is estimated to be P _d1 .

  Hereinafter, the initial posture A will be described.

  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 are otherwise the same. That is, the action probability estimation unit 501 executes the steps S62 and S63, and waits while recording until the Doppler RCS value 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, Go to step S64. In step 64, the behavior determination deviation E is calculated using a predetermined method or equation (26).

Next, the behavior probability estimating unit 501 obtains an initial posture correction term B _i as a posture probability using Equation 29 based on the posture probability estimated value P _i of the initial posture referred to from the memory 41.

At this time, C may be any natural number. Furthermore attitude probability after action completed determined by the posture probability estimation unit 491 obtains a post-action position correction term A _i in the same manner as Formula 29 (S64). In the present embodiment, since the action determination deviation E is a variable indicating the correlation between the teacher data and a certain code, the action when E becomes the minimum is a result. Thus, if the smallest variable when B _i also became the most probable position may be used any expression.

Thereafter, the deviation E _pi after the probability correction is obtained by Expression 30. Thus, _{P A} of the step S66 of the initial attitude A is calculated.

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

Thus calculated, in step S61~ step S66, the initial posture A posture probability _{P a1,} a plurality of actions of behavior probability _P a21 specified based on the initial position _{A, P a22,} a ... in step S64 Then, the posture probabilities P _a31 , P _a32 ,... Of the rear posture as a result of _performing each of the plurality of actions after the initial posture A are calculated in step S65. Then, in step S66, the a posture probability _{P a1} of initial posture A, the plurality of behavior probability _{P a21, P a22,} with one of out of ..., attitude probability of the rear position _{P a31, P a32,} ... of calculating a minimum value of one of the three product of all possible combinations of the probability of out as behavior probability P _a.

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

The action probability estimating unit 501 compares the values P _A , P _B , P _C , P _D ,... As the probability-corrected deviations E _pi calculated in all the initial postures A to D,. Is determined as the behavior of the living body (S72).

  INDUSTRIAL APPLICATION This indication can be utilized for the sensor and estimation method which estimate the direction and position of a moving body using a radio signal. In particular, direction estimation methods and directions mounted on measuring instruments that measure the direction and position of moving objects including living bodies and machines, home appliances that control according to the direction and position of moving objects, monitoring devices that detect intrusion of moving objects, etc. The present invention can be used for an estimation method, a position estimation method, and an estimating apparatus at most 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 correspondence state 50 living body 410 first matrix calculation section 420 second matrix extraction section 430 number estimation section 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 Operation period extraction unit 511 Direction code calculation Unit 512 Operation 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 where a living body can exist;
A part of the N transmission signals respectively transmitted by the N transmission antenna elements receives N reception signals including reflection signals reflected or scattered by the living body, respectively. A receiver having M (M is a natural number of 3 or more) receiving antenna elements;
Circuit and
And a memory,
The circuit is
From each of the N reception signals received in a predetermined period in each of the M reception antenna elements, the N transmission antenna elements and the M reception antenna elements were combined in a one-to-one correspondence. For each of the N × M combinations, a complex transfer function indicating a propagation characteristic 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 calculation unit for sequentially calculating an N × M first matrix,
By sequentially extracting a second matrix corresponding to a predetermined frequency range in the first matrix sequentially calculated by the first matrix calculation unit, the vital activity including at least one of the respiration, heartbeat, and body movement of the living body A second matrix extraction unit for sequentially extracting the second matrix corresponding to the affected component;
Presence / absence determination unit that performs a presence / absence determination to determine whether a living body exists within the predetermined range by a predetermined method,
After the presence / absence determination unit determines that a living body exists within the predetermined range, the second matrix extraction unit sequentially extracts the position of the living body with respect to the sensor using the second matrix extracted by the second matrix extraction unit. A position estimator for sequentially estimating,
(I) The position where the living body is sequentially estimated based on the position where the living body is sequentially estimated by the position estimating unit, the position of the transmission signal generator, and the position of the receiver. And a second distance indicating a distance between the living body and the receiver, and (ii) calculating the first distance and the second distance indicating the distance between the living body and the receiver. A Doppler RCS calculator that sequentially calculates a Doppler RCS (Rader cross-section) value for the living body using a second distance,
The position where the living body is sequentially estimated is stored in the memory a predetermined number of times in the estimated order, and the position where the living body is present is determined using the position where the living body is stored in the memory the predetermined number of times. If the transition is equal to or greater than a predetermined value, the living body is determined to be moving, and if less than the predetermined value, the movement determining unit determines that the living body is not moving,
A Doppler RCS threshold setting unit that sets a Doppler RCS threshold by a predetermined method,
Comparing the calculated Doppler RCS value with the set Doppler RCS threshold, and a Doppler RCS threshold determination unit that 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 behavior of the living body is selectively performed in accordance with at least one of the determination result in the movement determination unit and the determination result in the Doppler RCS threshold determination unit. An estimator; and a sensor. The situation estimating unit,
When it is determined that the living body has not moved in the movement determination unit, and when the Doppler RCS value is determined to be equal to or less than the Doppler RCS threshold value in the Doppler RCS threshold determination unit, the posture of the living body is estimated. Do
The sensor according to claim 1, wherein when the Doppler RCS value is determined by the Doppler RCS threshold value determination unit to be larger than the Doppler RCS threshold value, the behavior of the living body is estimated. The situation estimating unit,
The sensor according to claim 1, wherein when the movement determination unit determines that the living body is moving, the behavior of the living body is determined to be moving. At least three transmission antenna elements of the N transmission antenna elements are respectively arranged at different positions in a vertical direction and a horizontal direction,
At least three of the M receiving antenna elements are arranged at different positions in the vertical and horizontal directions, respectively.
The memory stores Doppler RCS value, and a vertical position that is a position in the vertical direction where the living body exists with respect to the sensor, and information indicating a correspondence relationship between the posture of the living body,
The position estimating unit estimates, as the position where the living body is present, a three-dimensional position including a vertical position that is a position in the vertical direction where the living body is present with respect to the sensor,
The situation estimation unit estimates the posture of the living body using the calculated Doppler RCS value, and the vertical position, and the information indicating the correspondence stored in the memory.
The sensor according to claim 1. At least three transmission antenna elements of the N transmission antenna elements are respectively arranged at different positions in a vertical direction and a horizontal direction,
At least three of the M receiving antenna elements are arranged at different positions in the vertical and horizontal directions, respectively.
The memory stores Doppler RCS value, and a vertical position that is a position in the vertical direction where the living body exists with respect to the sensor, and information indicating a correspondence relationship between the posture of the living body,
The position estimating unit estimates, as the position where the living body is present, a three-dimensional position including a vertical position that is a position in the vertical direction where the living body is present 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. Is estimated as the posture of the living body,
The sensor according to claim 1. The situation estimating unit, the sequentially calculated Doppler RCS value, and, using the sequentially estimated position of the living body, after successively estimating the posture of the living body, the sequentially estimated posture of the living body Stored in the 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,
The sensor according to claim 1. The situation estimating unit,
The Doppler RCS value calculated sequentially, and, after sequentially estimating the posture of the living body using the position where the living body is estimated sequentially, storing the posture of the living body sequentially estimated in the memory,
Next, before estimating the posture of the living body, the apparatus waits until the sequentially calculated Doppler RCS value becomes equal to or less than the Doppler RCS threshold, and the N number of times when 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 as a rear posture,
Using the front posture, which is the posture of the living body previously estimated stored in the memory, and the estimated rear posture, the behavior of the living body is estimated,
The sensor according to any one of claims 1 to 6. The situation estimating unit,
The Doppler RCS value calculated sequentially, and, after sequentially estimating the posture of the living body using the position where the living body is estimated sequentially, storing the posture of the living body sequentially estimated in the memory,
Wait until the sequentially calculated Doppler RCS value 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, one or more next behaviors of the living body are estimated using a front posture that is a posture of the living body estimated last time stored in the memory,
Using the sequentially calculated Doppler RCS value and the sequentially estimated position of the living body, specifying one of the estimated one or more next actions to determine the behavior of the living body The sensor according to any one of claims 1 to 6. The situation estimating unit,
The Doppler RCS value calculated sequentially, and, after sequentially estimating the posture of the living body using the position where the living body is estimated sequentially, storing the posture of the living body sequentially estimated in the memory,
Wait until the sequentially calculated Doppler RCS value 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, one or more next behaviors of the living body are estimated using a front posture that is a posture of the living body estimated last time stored in the memory,
Using the sequentially calculated Doppler RCS value and the sequentially estimated position of the living body, an action probability that is a probability of each of the estimated one or more next actions is estimated as the action of the living body. The 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, and when the number of living organisms is 0, determines that the living organism does not exist in the predetermined range, and the number of living organisms is The sensor according to any one of claims 1 to 9, wherein it is determined that the living body exists in the predetermined range when the number is one or more. An estimating device comprising a circuit and a memory,
The circuit is
Of the N transmission signals transmitted by 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 where a living body can exist. From a receiver having M (M is a natural number of 3 or more) receiving antenna elements, each of which receives N reception signals including a reflection signal in which some transmission signals are reflected or scattered by the living body, An acquisition unit configured to acquire the N reception signals received in a predetermined period in each of the M reception antenna elements;
For each of the N × M combinations obtained by combining the N transmission antenna elements and the M reception antenna elements on a one-to-one basis from each of the obtained N reception signals, Calculating a complex transfer function indicating a propagation characteristic between the transmitting antenna element and the receiving antenna element, and sequentially calculating a first N × M matrix having the calculated N × M complex transfer function as a component; One matrix calculation unit,
By sequentially extracting a second matrix corresponding to a predetermined frequency range in the first matrix sequentially calculated by the first matrix calculation unit, the vital activity including at least one of the respiration, heartbeat, and body movement of the living body A second matrix extraction unit for sequentially extracting the second matrix corresponding to the affected component;
Presence / absence determination unit that performs a presence / absence determination to determine whether a living body exists within the predetermined range by a predetermined method,
After the presence / absence determination unit determines that a living body is present in the predetermined range, the second matrix extraction unit sequentially extracts the second matrix, and uses the second matrix for the transmission signal generator and the receiver. A position estimating unit for sequentially estimating the position where the living body is present,
(I) the position of the living body, the position of the transmission signal generator, and the position of the receiver, which are sequentially estimated by the position estimating unit; 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, A Doppler RCS calculator for sequentially calculating a Doppler RCS (Rader cross-section) value for the living body,
The position where the living body is sequentially estimated is stored in the memory a predetermined number of times in the estimated order, and the position where the living body is present is shifted using the position where the living body is stored in the memory the predetermined number of times. Is greater than or equal to a predetermined value, the living body is determined to be moving, if less than the predetermined value, the movement determining unit determines that the living body is not moving,
A Doppler RCS threshold setting unit that sets a Doppler RCS threshold by a predetermined method,
Comparing the calculated Doppler RCS value with the set Doppler RCS threshold, and a Doppler RCS threshold determination unit that determines whether the Doppler RCS value is equal to or less than the Doppler RCS threshold,
Situation estimation for selectively performing one of the estimation of the posture of the living body and the estimation of the behavior of the living body in accordance with at least one of the judgment result of the movement judgment unit and the judgment result of the Doppler RCS threshold judgment unit. And an estimating device comprising: An estimation method performed in an estimation device including a circuit and a memory,
Of the N transmission signals transmitted by 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 where a living body can exist. From a receiver having M (M is a natural number of 3 or more) receiving antenna elements, each of which receives N reception signals including a reflection signal in which some transmission signals are reflected or scattered by the living body, Obtaining the N received signals received in a predetermined period in each of the M receiving antenna elements;
For each of the N × M combinations obtained by combining the N transmission antenna elements and the M reception antenna elements on a one-to-one basis from each of the obtained N reception signals, Calculating a complex transfer function indicating a propagation characteristic between the transmitting antenna element and the receiving antenna element, and sequentially calculating an N × M first matrix having the calculated N × M complex transfer function as a component;
By sequentially extracting a second matrix corresponding to a predetermined frequency range in the sequentially calculated first matrix, it is possible to correspond to a component affected by vital activity including at least one of respiration, heartbeat, and body movement of the living body Sequentially extracting the second matrix
Perform a presence / absence determination to determine whether a living body exists within the predetermined range by a predetermined method,
After it is determined that the living body exists within the predetermined range, using the sequentially extracted second matrix, the transmission signal generator and the position of the living body with respect to the receiver are sequentially estimated,
The position where the living body is sequentially estimated, the position of the transmission signal generator, and the position of the receiver, based on the first distance indicating the distance between the living body and the transmission signal generator, and , Sequentially calculating a second distance indicating the distance between the living body and the receiver,
Using the calculated first distance and the second distance, a Doppler RCS (Rader cross-section) value for the living body is sequentially calculated,
The position where the living body is sequentially estimated is stored in the memory a predetermined number of times in the estimated order,
If the change of the position where the living body is present is equal to or more than a predetermined value using the position where the living body is stored in the memory the predetermined number of times, it is determined that the living body is moving, and is less than the predetermined value. In the case of, performing a movement determination to determine that the living body has not moved,
Setting a Doppler RCS threshold by a predetermined method,
Comparing the calculated Doppler RCS value with the set Doppler RCS threshold, performing a Doppler RCS threshold determination to determine whether the Doppler RCS value is equal to or less than the Doppler RCS threshold,
An estimation method for selectively performing one of the estimation of the posture of the living body and the estimation of the behavior of the living body in accordance with at least one of a determination result in the movement determination and a determination result in the Doppler RCS threshold determination. An estimation method performed in an estimation device including a circuit and a memory,
Of the N transmission signals transmitted by 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 where a living body can exist. From a receiver having M (M is a natural number of 3 or more) receiving antenna elements, each of which receives N reception signals including a reflection signal in which some transmission signals are reflected or scattered by the living body, Obtaining the N received signals received in a predetermined period in each of the M receiving antenna elements;
For each of the N × M combinations obtained by combining the N transmission antenna elements and the M reception antenna elements on a one-to-one basis from each of the obtained N reception signals, Calculating a complex transfer function indicating a propagation characteristic between the transmitting antenna element and the receiving antenna element, and sequentially calculating an N × M first matrix having the calculated N × M complex transfer function as a component;
By sequentially extracting a second matrix corresponding to a predetermined frequency range in the sequentially calculated first matrix, it is possible to correspond to a component affected by vital activity including at least one of respiration, heartbeat, and body movement of the living body Sequentially extracting the second matrix
Perform a presence / absence determination to determine whether a living body exists within the predetermined range by a predetermined method,
After it is determined that the living body exists within the predetermined range, using the sequentially extracted second matrix, the transmission signal generator and the position of the living body with respect to the receiver are sequentially estimated,
The position where the living body is sequentially estimated, the position of the transmission signal generator, and the position of the receiver, based on the first distance indicating the distance between the living body and the transmission signal generator, and , Sequentially calculating a second distance indicating the distance between the living body and the receiver,
Using the calculated first distance and the second distance, a Doppler RCS (Rader cross-section) value for the living body is sequentially calculated,
The position where the living body is sequentially estimated is stored in the memory a predetermined number of times in the estimated order,
If the change of the position where the living body is present is equal to or more than a predetermined value using the position where the living body is stored in the memory the predetermined number of times, it is determined that the living body is moving, and is less than the predetermined value. In the case of, performing a movement determination to determine that the living body has not moved,
Setting a Doppler RCS threshold by a predetermined method,
Comparing the calculated Doppler RCS value with the set Doppler RCS threshold, performing a Doppler RCS threshold determination to determine whether the Doppler RCS value is equal to or less than the Doppler RCS threshold,
A method for selectively performing one of the estimation of the posture of the living body and the estimation of the behavior of the living body in accordance with at least one of a determination result in the movement determination and a determination result in the Doppler RCS threshold determination. Program to be executed.

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