JP2019211458A - Estimation device and estimation method - Google Patents

Abstract

To provide an estimation device capable of improving resolution and accuracy of a biological body direction estimated.SOLUTION: An estimation device 10 for estimating a biological body direction comprises: transmission/reception parts 20A-20H for transmitting a transmitter signal using M transmission antenna elements which are arranged to surround a prescribed range A1 including a biological body 100, and receiving a reception signal using N reception antenna elements; and a circuit 40 for calculating a feature amount which indicates a large amplitude and more regular waveform as N reception signals have a larger value, for each of M set of N reception signals respectively corresponding to M transmission signals, comparing M feature amounts acquired by calculation for identifying a first transmission antenna element corresponding to the first feature amount which is maximum out of M feature amounts, and then, estimating the prescribed direction on the basis of the identified first transmission antenna element as the biological body direction.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to an estimation apparatus and an estimation method that irradiate a living body with a radio signal, receive a reflection signal thereof, and estimate a living body direction that is a direction in which the front of the living body is facing.

  Patent Document 1 discloses an apparatus that estimates whether a living body is lying on its back or lying down by irradiating a living body on a bed with electromagnetic waves and detecting vibrations of heartbeat and respiration contained in the reflected wave. It is disclosed.

  Patent Document 2 discloses an apparatus that irradiates electromagnetic waves toward a pile of rubble at a disaster rescue site and detects the presence or absence of a survivor from the reflected waves.

JP 2014-207935 A Japanese Patent Laid-Open No. 11-6874

  However, in the prior art, the direction of the living body cannot be estimated with a finer resolution.

  In order to achieve the above object, an estimation apparatus according to the present disclosure is an estimation apparatus that estimates a biological direction that is a direction in which the front of a living body is facing, and is arranged to surround a predetermined range including the living body. Transmitters that transmit M transmission signals to the predetermined range using M (M is 3 or more) transmission antenna elements, and N (N is 2 or more) arranged around the predetermined range Each of the reception units includes a reception signal including a signal obtained by reflecting, transmitting, or scattering the M transmission signals by the living body using a reception antenna element included in each of the N reception units. N reception units for receiving a period, and a circuit, and the circuit includes N reception signals of M sets each corresponding to the M transmission signals transmitted by the M transmission antenna elements. For each set of Based on the N received signals, a feature value indicating that the larger the value is, the larger the amplitude is and the more regular waveform is calculated, and the M feature values obtained by the calculation are calculated. By comparing with each other, a first transmission antenna element corresponding to the maximum first feature quantity among the M feature quantities is identified, and a predetermined direction based on the identified first transmission antenna element is determined as the living body. Estimated as direction.

  These general or specific aspects may be realized by a system, a method, an integrated circuit, a computer program, or a recording medium such as a computer-readable CD-ROM. The system, method, integrated circuit, computer program And any combination of recording media.

  According to the estimation apparatus according to the present disclosure, it is possible to improve the resolution and accuracy of the estimated biological direction in the estimation of the biological direction, which is the direction in which the front of the biological body is facing.

FIG. 1 is a configuration diagram illustrating an example of an estimation apparatus according to an embodiment. FIG. 2 is a block diagram illustrating an example of a functional configuration of a circuit in the embodiment. FIG. 3 is a diagram for describing a method of calculating the sum of the maximum heights of the received waveforms in the embodiment. FIG. 4 is an example showing the result of estimating the direction of the living body in the room layout shown in FIG. FIG. 5 is a diagram showing a floor plan of a room in which the direction of the living body is estimated. FIG. 6 is an example of a display indicating a determination result that attention is directed to the television when the living body is facing the east side in the situation of FIG. FIG. 7 is a flowchart illustrating an example of the operation of the estimation device according to the embodiment. FIG. 8 is a diagram illustrating the absolute value of the channel response of the transmitting antenna in the front direction, which is observed in the test by the estimation apparatus according to the embodiment. FIG. 9 is a diagram illustrating the absolute value of the channel response of the transmitting antenna in the lateral direction, which is observed in the test by the estimation apparatus according to the embodiment. FIG. 10 is a diagram illustrating the absolute value of the channel response of the transmitting antenna in the rear direction, which is observed in the test by the estimation apparatus according to the embodiment. FIG. 11 is a diagram illustrating an example of a result of calculating feature amounts from absolute values of eight channel responses. FIG. 12 is a diagram illustrating an example in which the result of FIG. 11 is approximated by a quadratic function.

(Knowledge that became the basis of the present invention)
The inventors conducted a detailed study on the prior art related to the direction estimation of a living body using electromagnetic waves. In the method of Patent Document 1, it is disclosed that when a reflected wave is received by irradiating a living body with electromagnetic waves, a determination is made that if the amount of change in the received signal is greater than or equal to a threshold value, it is supine, and if it is less than the threshold value, prone. However, in this method, it is possible to estimate the approximate direction in which the front of the living body is facing, but there is a small amount of the front of the body, such as a change in the direction of the front of the body that accompanies getting-off movement as required for nursing care. The direction cannot be estimated.

  Further, in Patent Document 2, when a living body is irradiated with electromagnetic waves, the waveform of the reflected wave on the front surface of the living body has a larger amplitude and regularity than the reflected waveform on the other surface of the living body. The knowledge that there is is disclosed. However, Patent Document 2 does not disclose a method for quantitatively measuring that the amplitude is large and regular, and in order to know the detailed direction in which the front of the living body is facing, It is necessary to visually determine the reflected waveform obtained by the user and determine the detailed direction in which the front of the living body is facing based on experience.

  As a result of repeated research on the above problems, the inventors have improved the resolution and accuracy in the direction of the living body in which the front of the living body estimated by the estimation device is facing, as in Patent Document 1, one direction In addition to transmitting transmission signals from and receiving the reflected waves, multiple antennas are installed around the living body to transmit transmission waves from various directions, and reflected waves, transmitted waves or We thought that it was important to capture more features of the living body by receiving scattered waves. In addition, it is considered important to use features that can quantitatively evaluate the characteristics of the reflected waveform from the front of the living body disclosed in Patent Document 2, that is, that the amplitude is large and regular. It was.

  As a result, the inventors have invented the following estimation apparatus and estimation method.

  That is, the estimation apparatus according to the present disclosure is an estimation apparatus that estimates the direction of the living body, which is the direction in which the front of the living body is facing, and is arranged around a predetermined range including the living body (M is 3 or more). ) Transmitting unit that transmits M transmission signals to the predetermined range using the transmitting antenna element of N), and N (N is 2 or more) receiving units arranged around the predetermined range, N reception signals each including a signal obtained by reflecting, transmitting or scattering the M transmission signals by the living body are received for a predetermined period using reception antenna elements included in the N reception units. A reception unit and a circuit, and the circuit includes, for each set of N reception signals, M sets, each of which corresponds to the M transmission signals transmitted by the M transmission antenna elements. N pieces included in the set Based on the signal, the larger the value, the larger the amplitude and the feature amount indicating that the waveform is more regular, and the M feature amounts obtained by the calculation are compared with each other, A first transmission antenna element corresponding to the maximum first feature quantity among the M feature quantities is identified, and a predetermined direction based on the identified first transmission antenna element is estimated as the biological direction.

  According to this, the transmission antenna element corresponding to the maximum first feature quantity among the M feature quantities corresponding to the M transmission signals transmitted from the M transmission antenna elements arranged around the predetermined range. The predetermined direction based on is determined as the biological direction. As described above, the resolution and accuracy of the biological direction estimated by arranging the transmitting antenna element and the receiving antenna element around a predetermined range can be improved.

  For example, for each set of the M received signals of the M sets, the circuit converts a DC (Direct Current) component of a first received waveform based on the N received signals included in the set into the first received waveform. The feature amount may be calculated from a second received waveform obtained by removing from the second received waveform.

  Thereby, it is possible to suppress a DC component, which is an unnecessary component for identification of a living body, from the received signal, and to perform living body identification efficiently.

  For example, the circuit may calculate the sum of the maximum heights of the second received waveform as the feature amount.

  For example, the circuit may calculate a variance in the time direction of the second received waveform as the feature amount.

  For example, the circuit may calculate an integral value in a predetermined frequency range of a function obtained by performing frequency domain conversion on the second received waveform as the feature amount.

  For example, the circuit includes a first direction of the identified first transmission antenna element with respect to the predetermined range, the first feature amount corresponding to the first transmission antenna element, and the M transmission antenna elements. And two or more second directions of the two or more second transmission antenna elements arranged within a predetermined distance from the first transmission antenna element with respect to the predetermined range and the two or more second transmission antenna elements, respectively. An approximation function having an upwardly convex curve with respect to two or more second feature quantities corresponding to is performed by approximation using an approximation function indicating a relationship between the direction with respect to the predetermined range and the feature quantity. The direction in which the obtained approximate curve takes the maximum value may be estimated as the biological direction.

  According to this, the maximum first feature value, two or more second feature values corresponding to two or more second transmit antenna elements in the vicinity of the first transmit antenna element corresponding to the first feature value, By performing approximation using an approximation function using a first direction and two or more second directions with respect to a predetermined range of one transmission antenna element and two or more second transmission antenna elements, direction estimation with a finer resolution can be performed. .

  These general or specific aspects may be realized by a system, a method, an integrated circuit, a computer program, or a computer-readable recording medium such as a CD-ROM. The system, method, integrated circuit, computer You may implement | achieve with arbitrary combinations of a program and a recording medium.

  Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that each of the embodiments described below shows a preferred specific example of the present disclosure. Numerical values, shapes, materials, components, arrangement positions and connection forms of components, steps, order of steps, and the like shown in the following embodiments are merely examples, and are not intended to limit the present disclosure. In addition, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims indicating the highest concept of the present disclosure are described as optional constituent elements that constitute a more preferable embodiment. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

(Embodiment)
FIG. 1 is a configuration diagram illustrating an example of a configuration of an estimation device according to an embodiment.

  As illustrated in FIG. 1, the estimation device 10 includes eight transmission / reception units 20 </ b> A to 20 </ b> H and a circuit 40. The estimation apparatus 10 transmits transmission signals from the transmission / reception units 20A to 20H to a predetermined range A1 including the living body 100 such as a human, and includes signals reflected, transmitted, or scattered by the living body 100 by the transmission / reception units 20A to 20H. Receive a received signal. The estimation device 10 processes a reception signal received by the transmission / reception units 20 </ b> A to 20 </ b> H in the circuit 40, thereby estimating a living body direction that is a direction in which the front surface of the living body 100 is facing.

  Each of the eight transmission / reception units 20A to 20H includes one antenna element 30A to 30H. The transmission / reception units 20A to 20H transmit transmission signals to the predetermined range A1 using the antenna elements 30A to 30H, respectively. Thereby, the antenna elements 30A to 30H specifically emit microwaves as transmission signals to the living body 100 such as a human. The transmission / reception units 20A to 20H may transmit unmodulated transmission signals from the antenna elements 30A to 30H, or may transmit transmission signals subjected to modulation processing. When the modulation process is performed, the transmission / reception units 20A to 20H may include a circuit for performing the modulation process. The antenna elements 30A to 30H are arranged so as to surround the predetermined range A1 at positions around the predetermined range A1, that is, positions outside the predetermined range A1. For example, the antenna elements 30A to 30H are respectively arranged at different eight positions with respect to the predetermined range A1. The different eight directions are, for example, directions determined by dividing 360 ° into eight equal parts around the center position of the predetermined range A1. The eight transmission / reception units 20A to 20H may be arranged so as to surround the predetermined range A1 together with the antenna elements 30A to 30H. Further, the eight transmission / reception units 20A to 20H may be arranged at positions different from the antenna elements 30A to 30H.

  The predetermined range A1 is a space in a predetermined range for the estimation apparatus 10 to estimate the direction of the living body 100.

  Each of the transmission / reception units 20A to 20H uses the antenna elements 30A to 30H each having a reception signal including a signal in which the transmission signal from the transmission / reception units 20A to 20H is reflected, transmitted, or scattered by the living body 100, for a predetermined period. Receive. Each of the transmission / reception units 20A to 20H may convert the frequency of the received signal into a low frequency signal. In addition, each of the transmission / reception units 20A to 20H may perform demodulation processing on the reception signal. Each of the transmission / reception units 20 </ b> A to 20 </ b> H outputs a signal obtained by frequency conversion and / or demodulation processing to the circuit 40. Each of the transmission / reception units 20A to 20H may include a circuit for processing a reception signal.

  In addition, the antenna elements 30A to 30H are configured to serve as both the transmitting antenna element and the receiving antenna element. However, the configuration is not limited thereto, and the transmitting antenna element and the receiving antenna element may be configured separately. In addition, when the transmission antenna element and the reception antenna element have separate structures, the number of transmission antenna elements and the number of reception antenna elements may be different from each other. The number of transmitting antenna elements is not limited to eight, and may be, for example, M (M is 3 or more). The number of receiving antenna elements is not limited to eight, and may be N (N is 2 or more), for example. In addition, although the transmission / reception units 20A to 20H have a configuration in which a transmission unit that transmits a transmission signal and a reception unit that receives a reception signal are integrated, the transmission unit and the reception unit may be configured separately.

  Next, a functional configuration of the circuit 40 will be described.

  FIG. 2 is a block diagram illustrating an example of a functional configuration of a circuit in the embodiment.

  The circuit 40 includes a calculation unit 41, a comparison unit 42, and a direction estimation unit 43, and executes various processes for operating the estimation device 10. The circuit 40 includes, for example, a processor that executes a control program and a volatile storage area (main storage device) that is used as a work area used when the control program is executed. The volatile storage area is, for example, a RAM (Random Access Memory). The circuit 40 may be realized by a dedicated circuit that executes various processes for operating the estimation device 10. That is, the circuit 40 may be realized as a circuit that executes software processing, or may be realized as a circuit that executes hardware processing.

  The circuit 40 temporarily stores a signal acquired from each of the transmission / reception units 20A to 20H in a volatile storage area for a predetermined period. The circuit 40 may temporarily store the phase and amplitude of the signal for a volatile storage area for a predetermined period. Note that the circuit 40 may have a nonvolatile storage area, and the signal may be temporarily stored in the nonvolatile storage area for a predetermined period.

  Hereinafter, each process performed by the calculation unit 41, the comparison unit 42, and the direction estimation unit 43 included in the circuit 40 will be described in order.

  First, calculation of the feature amount performed by the calculation unit 41 will be described.

  The calculation unit 41 uses the received signal stored in the storage area of the circuit 40 to calculate the propagation channel H (t) of the received signal.

  Here, a propagation channel H (t obtained by arranging a MIMO (Multiple-Input and Multiple-Output) array antenna composed of M transmitting antenna elements and N receiving antenna elements around the living body 100. ) Is represented by Equation 1 below.

In Equation 1, h _ij represents the complex channel response from the j-th transmitting antenna to the i-th receiving antenna, and t represents the observation time.

  Next, the calculation unit 41 calculates a DC removal channel obtained by removing a DC component, which is a component unnecessary for identification of the living body 100, from the propagation channel of the received signal represented by the following Expression 2. For each set of M received signals of M sets, the calculation unit 41 removes the DC component of the first received waveform based on the N received signals included in the set from the first received waveform, thereby removing the second received signal. A received waveform, ie, a DC rejection channel is obtained. The calculation unit 41 may store the calculated DC removal channel in the storage area of the circuit 40.

  Here, the DC removal channel c (t) of the received signal is obtained by subtracting the DC component calculated by the measurement time average of each component from each component of the propagation channel, as shown in Equation 3 and Equation 4 below. Is calculated.

Here, N indicates the number of snapshots, F _s represents the sampling frequency, T is shows the measurement time.

  The DC component removal method is not limited to the method represented by the right side of Equation 3. For example, the DC component may be removed by subtracting a propagation channel obtained in an unattended predetermined range A1 where the living body 100 is not present.

  The calculation unit 41 then increases the amplitude of the second reception waveform corresponding to the transmission antenna for each transmission antenna element based on the N DC removal channels for each of the antenna elements 30A to 30H as the value increases. In addition, a feature amount indicating a more regular waveform is calculated. The feature amount calculated by the calculation unit 41 is, for example, a predetermined function that is obtained by summing the maximum values of the received waveform, the sum of the absolute values of the received waveform, the variance of the received waveform, and the frequency domain conversion of the received waveform. At least one of the integral values in the frequency range.

  First, the case where the calculation unit 41 calculates the sum of the maximum heights of the received waveforms as the feature amount will be described.

  FIG. 3 is a diagram for explaining a method for calculating the sum of the maximum heights of the received waveforms.

  First, the calculation unit 41 detects the maximum value of the target waveform, here, the second received waveform. In FIG. 3, the maximum value is indicated by a triangular point P2. Next, two sections R1 and R2 are specified for each of the left and right by drawing a line horizontally from the point P2 and extending it to the left and right until it intersects with the waveform or reaches the left or right end of the signal. Then, the points P1 and P2, which are the minimum values of the signals in each of the two sections R1 and R2, are specified. Then, the higher point P3 of the points P1 and P3 which are the minimum values of the two intervals is set as the reference level, and the vertical distance from the reference level to the maximum value is determined as the maximum value height. The maximum value height is calculated for all the maximum values of the received waveform of the DC removal channel corresponding to the transmission antenna element, and the sum of the maximum value heights of all the maximum values is calculated. A feature quantity s (j) corresponding to is obtained. Here, the calculation unit 41 may calculate the feature amount without including the maximum value whose maximum value height is equal to or smaller than the threshold value in the sum of the maximum value heights in order to reduce the influence of the disturbance of the reception waveform due to noise. .

  Further, the calculation unit 41 may calculate the sum of absolute values of the N DC removal channels as the feature amount s (j). In this case, the calculation unit 41 calculates the feature quantity s (j) using the following Expression 5.

  Further, the calculation unit 41 may calculate the variance of the received waveform of the DC removal channel of the propagation channel for each of the M transmission antenna elements as the feature quantity s (j). In this case, the calculation unit 41 calculates the feature quantity s (j) using the following Expression 6.

  Here, var_k indicates the variance for the variable k.

  Further, the calculation unit 41 calculates an integral value in a predetermined frequency range of the function F obtained by performing frequency domain conversion on the reception waveform of the DC removal channel of the propagation channel for each of the M transmission antenna elements as a feature quantity s (j). May be calculated as In this case, the calculation unit 41 calculates the feature quantity s (j) using the following Expression 7.

  The calculation unit 41 calculates at least one feature amount among the three types of feature amounts, and outputs the calculated at least one feature amount to the comparison unit 42.

  The comparison unit 42 compares the M feature amounts corresponding to the M transmission antenna elements obtained by the calculation in the calculation unit 41 with each other, thereby making the first feature amount that is the maximum among the M feature amounts. The first transmitting antenna element corresponding to is specified.

  The direction estimation unit 43 estimates a predetermined direction based on the first transmission antenna element specified by the comparison unit 42 as a biological direction that is a direction in which the front of the living body 100 is facing. In the simplest example, the direction estimation unit 43 estimates the direction with respect to the predetermined range A1 where the first transmission antenna element corresponding to the first feature amount that is the largest among the M feature amounts is the biological direction, The estimated direction is output as an estimation result.

  In addition, the direction estimation unit 43 estimates the direction other than the direction with respect to the predetermined range A1 where the transmission antenna element is located, for example, the direction to the position between the two transmission antenna elements as the biological direction by using the following method. May be. Specifically, the direction estimation unit 43 includes a first direction with respect to the predetermined range A1 of the first transmission antenna element specified by the comparison unit 42, a first feature amount corresponding to the first transmission antenna element, and M number of pieces. Among the transmission antenna elements, two or more second directions with respect to a predetermined range A1 of two or more second transmission antenna elements arranged within a predetermined distance from the first transmission antenna element, and two or more second transmission antennas The direction in which the approximate curve obtained by applying the approximate function with respect to two or more second feature quantities each corresponding to the element takes the maximum value may be estimated as the biological direction. Note that the direction estimation unit 43 may identify, for example, two transmission antenna elements that are arranged adjacent to the first transmission antenna element as two or more second transmission antenna elements. Good. The approximate function is an approximate function having an upwardly convex curve, and is an approximate function indicating the relationship between the direction and the feature amount with respect to the predetermined range A1.

  Thus, since the direction estimation unit 43 estimates the direction in which the approximate function takes the maximum value as the biological direction, the biological direction resolution can be improved without increasing the number of transmission antenna elements. In addition, the direction estimation unit 43 stores the estimation results for a predetermined number of times and sets the average value as the final living body direction, thereby reducing the influence of noise included in the received waveform.

  The estimation device 10 may further include a display unit 50 that displays the estimated direction of the living body. FIG. 4 is an example showing the result of estimating the direction of the living body in the room 60 shown in FIG. The room 60 is an example of the predetermined range A1. As shown in this example, there are a method of displaying the direction of the living body, for example, a method of displaying the direction of the front of the living body, a method of rotating an icon indicating the living body, and the like.

  In addition, the direction in which the front of the living body is facing is likely to be the direction in which the living body is paying attention or the direction of the living body's intention. For this reason, the display unit 50 may display a target with attention or a target with an intention instead of displaying the direction of the living body described above. FIG. 6 is an example of a display showing a determination result that attention is directed to the television when the living body is facing the east side in the situation of FIG. In this case, the estimation apparatus 10 stores information in which the direction in the room 60 is associated with the type of the object arranged on the direction side of the room 60, and the estimated living body is stored using the information. The type of the object corresponding to the direction in which the living body is facing from the estimated direction is displayed on the display unit 50 as a target to which the living body is paying attention.

  Moreover, you may perform remote control of an apparatus or an illumination instead of displaying the object to which the display part 50 is paying attention of a biological body. For example, if there are multiple devices that can provide good visibility by turning on the illumination in the direction in which the biological attention is directed, or that can be operated by voice input, which device the user tries to operate It is possible to operate only appropriate devices.

  FIG. 7 is a flowchart illustrating an example of the operation of the estimation apparatus 10 according to the embodiment.

  In the estimation device 10, the antenna elements 30A to 30H transmit transmission signals to the predetermined range in a state where the living body 100 is disposed within the predetermined range A1 (S11). That is, in the estimation apparatus 10, the eight transmission signals are transmitted to the predetermined range A <b> 1 including the living body 100 using the antenna elements 30 </ b> A to 30 </ b> H by the eight transmission / reception units 20 </ b> A to 20 </ b> H.

  Next, the transmission / reception units 20A to 20H receive the reception signal including the signal in which the transmission signal is reflected, transmitted, or scattered by the living body 100 using the eight antenna elements 30A to 30H for a predetermined period (S12).

  Next, the calculation unit 41 removes the DC component of the first reception waveform based on the reception signals received by the transmission / reception units 20A to 20H from the first reception waveform (S13). As a result, the DC component is removed from the eight first received waveforms for each set of eight received signals, each of which has eight sets corresponding to the eight transmitted signals transmitted by the eight transmitting antenna elements. Eight second received waveforms are obtained for every eight sets.

  The calculating unit 41 calculates a feature amount from the eight second received waveforms obtained for each of the eight sets (S14). The calculation unit 41 calculates the sum of the maximum heights of the received waveform, the sum of the absolute values of the received waveform, the variance of the received waveform, and the integral value in a predetermined frequency range of a function obtained by frequency domain conversion of the received waveform. Is calculated as a feature amount.

  The comparison unit 42 compares the eight feature amounts obtained by the calculation in the calculation unit 41 with each other, thereby the first transmission antenna element corresponding to the first feature amount that is the largest among the eight feature amounts. Is specified (S15).

  The direction estimation unit 43 estimates a predetermined direction based on the first transmission antenna element specified by the comparison unit as a biological direction (S16).

  The inventors conducted a test to verify the estimation device 10. In the test, eight transceivers corresponding to the transceivers 20A to 20H were used. The eight transceivers are arranged in a circle with a radius of 0.5 m centering on the living body 100 and at intervals of 45 degrees. Here, each of the eight transceivers has a transmitting antenna element that is composed of one element and is a rectangular patch antenna. Each of the eight transceivers has a receiving antenna element that is composed of one element and is a rectangular patch antenna. The height from the floor surface to the position where the receiving antenna element is installed is 0.86 m. The transmitting antenna element is arranged immediately above one wavelength of the microwave of the receiving antenna element.

Here, FIG. 8 shows the absolute value | H ₁ (t) | of the channel response when the transmission antenna element located in the front direction of the living body 100 transmits a transmission signal. FIG. 9 shows the absolute value | H ₃ (t) | of the channel response when the transmission antenna element located in the lateral direction of the living body 100 transmits a transmission signal. FIG. 10 shows the absolute value | H ₅ (t) | of the channel response when the transmission antenna element located in the back direction of the living body 100 transmits a transmission signal.

8 to 10, it can be seen that only | H ₁ (t) | transmitted from the front has a large amplitude and a regular waveform is observed. An example of the result of calculating the feature amount from the absolute values of these eight channel responses is shown in FIG. In this case, it is determined that the first transmitting antenna element having the maximum feature amount is No. 2, and the front of the living body is oriented in a 45 ° direction. That is, the comparison unit 42 specifies the second transmission antenna element as the first transmission antenna element. In addition, direction approximation with a finer resolution can be performed by performing approximation using a function using the feature values of the transmission antenna having the maximum feature value and the neighboring transmission antennas.

  FIG. 12 is a diagram illustrating an example in which the result of FIG. 11 is approximated by a quadratic function.

  In this case, the direction estimation unit 43 extracts 45 ° that is the direction corresponding to the second transmission antenna element specified as the first transmission antenna element and the feature amount 0.88. In addition, the direction estimation unit 43 extracts 0 ° that is the direction corresponding to the first transmission antenna element adjacent to the second transmission antenna element and the feature amount 0.79. In addition, the direction estimation unit extracts 90 ° that is the direction corresponding to the third transmission antenna element adjacent to the second transmission antenna element and the feature amount 0.15. That is, the direction estimation unit 43 is a combination of three (“direction with respect to the transmission antenna element” and “feature”), P11 (0 °, 0.79), P12 (45 °, 0.88), and , P13 (90 °, 0.15), a direction corresponding to P14 indicating the maximum value of the curve obtained by approximating the three points with a quadratic function, for example, 30 ° can be estimated as the biological direction.

(Effect etc.)
According to the estimation apparatus 10 according to the present embodiment, the transmission antenna element corresponding to the maximum first feature quantity among the M feature quantities corresponding to the M transmission signals transmitted from the M transmission antenna elements. The predetermined direction based on is determined as the biological direction. As described above, the resolution and accuracy of the biological direction estimated by arranging the transmitting antenna element and the receiving antenna element around a predetermined range can be improved.

  Moreover, according to the estimation apparatus 10 according to the present embodiment, it corresponds to the maximum first feature quantity and two or more second transmission antenna elements in the vicinity of the first transmission antenna element corresponding to the first feature quantity. It is obtained by performing approximation using an approximation function using two or more second feature values, a first direction and two or more second directions with respect to a predetermined range of the first transmission antenna element and the two or more second transmission antenna elements. Since the predetermined direction is estimated as the biological direction, the direction can be estimated with a finer resolution.

  Moreover, the estimation apparatus 10 according to the present embodiment can estimate the direction in which the front surface of the living body 100 such as a human is facing using a radio signal such as a microwave. That is, since the estimation apparatus 10 according to the present embodiment can estimate the living body direction of the living body 100 such as a human without performing image analysis on an image captured by a camera or the like, Can be estimated.

  You may employ | adopt the apparatus which replaced the function of the transmission part and the function of the receiving part of the estimation apparatus 10 which concerns on the said embodiment as an estimation apparatus.

  INDUSTRIAL APPLICABILITY The present invention can be used in an estimation device that estimates the direction of a living body using a radio signal, and in particular, home appliances that perform control according to the direction of the living body, a system that detects and monitors the rising or turning of an elderly person, and the like Available to:

DESCRIPTION OF SYMBOLS 10 Estimation apparatus 20A-20H Transmission / reception part 30A-30H Antenna element 40 Circuit 41 Calculation part 42 Comparison part 43 Direction estimation part 50 Display part 100 Living body

Claims (7)

An estimation device for estimating a direction of a living body, which is a direction in which the front of the living body is facing,
A transmission unit that transmits M transmission signals to the predetermined range using M (M is 3 or more) transmission antenna elements arranged around the predetermined range including the living body;
N reception units (N is 2 or more) arranged around the predetermined range, and a reception signal including a signal in which the M transmission signals are reflected, transmitted, or scattered by the living body, N receiving units each receiving for a predetermined period using a receiving antenna element included in each of the N receiving units;
A circuit,
The circuit is
For each set of N received signals that are M sets corresponding to the M transmit signals transmitted by the M transmit antenna elements, the set is large based on the N received signals included in the set. Calculate the feature value that indicates that the value is larger and the waveform is more regular,
By comparing the M feature quantities obtained by the calculation with each other, the first transmission antenna element corresponding to the first feature quantity that is the maximum among the M feature quantities is specified,
An estimation device that estimates a predetermined direction based on the identified first transmission antenna element as the biological direction. The circuit removes, from the first received waveform, a DC (Direct Current) component of the first received waveform based on the N received signals included in the set for each set of the M received signals of the M sets. The estimation device according to claim 1, wherein the feature amount is calculated from a second received waveform obtained by performing the processing. The estimation device according to claim 2, wherein the circuit calculates a sum of maximum heights of the second received waveform as the feature amount. The estimation device according to claim 2, wherein the circuit calculates a variance in the time direction of the second received waveform as the feature amount. The estimation device according to claim 2, wherein the circuit calculates, as the feature amount, an integral value in a predetermined frequency range of a function obtained by performing frequency domain conversion on the second received waveform. The circuit includes a first direction of the identified first transmission antenna element with respect to the predetermined range, the first feature amount corresponding to the first transmission antenna element, and the M transmission antenna elements. Two or more second transmitting antenna elements arranged within a predetermined distance from the first transmitting antenna element correspond to two or more second directions with respect to the predetermined range, and each of the two or more second transmitting antenna elements. An approximation function having an upwardly convex curve with respect to two or more second feature quantities to be obtained, and obtained by performing approximation using an approximation function indicating the relationship between the direction with respect to the predetermined range and the feature quantity. The estimation apparatus according to any one of claims 1 to 5, wherein a direction in which the approximate curve takes a maximum value is estimated as the biological direction. An estimation method executed by an estimation device that estimates a biological direction that is a direction in which the front of the biological body is facing,
The estimation device includes:
A transmission unit that transmits M transmission signals to the predetermined range using M (M is 3 or more) transmission antenna elements arranged around the predetermined range including the living body, and surrounds the periphery of the predetermined range N receivers (N is 2 or more) arranged in the circuit and a circuit,
In the estimation method,
Using the M transmitting antenna elements, the transmission signal is transmitted to the predetermined range including the living body,
Using the N reception antenna elements of the N reception units, a reception signal including a signal in which the transmission signal is reflected, transmitted, or scattered by the living body is received for a predetermined period.
For each set of N received signals that are M sets corresponding to the M transmit signals transmitted by the M transmit antenna elements, the set is large based on the N received signals included in the set. Calculate the feature value that indicates that the value is larger and the waveform is more regular,
By comparing the M feature quantities obtained by the calculation with each other, the first transmission antenna element corresponding to the first feature quantity that is the maximum among the M feature quantities is identified,
An estimation method for estimating a predetermined direction based on the identified first transmission antenna element as the biological direction.

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