JP6887089B2 - Identification device and identification method - Google Patents

Description

The present invention relates to an identification device and an identification method for irradiating a living body with a wireless signal and receiving the reflected signal to identify the living body.

For example, Patent Document 1 discloses a device that identifies an individual by irradiating a driver of an automobile with an electromagnetic wave and extracting a heartbeat and heartbeat signal using the reflected wave.

Further, Patent Document 2 discloses a method of measuring the heart rate of a subject by using a plurality of transceivers for a driver of an automobile.

Further, Patent Document 3 discloses a 360-degree radiation pattern measuring device using a plurality of antennas for a subject.

Japanese Unexamined Patent Publication No. 2015-042293 JP-A-2009-055997 JP-A-2007-325621

However, biological identification using electromagnetic waves is used not only in a short distance such as a driver's seat space surrounded by steering wheels and seats like a car driver, but also in various situations such as identification from a distance of several meters. Is expected, and it is required to improve the degree of freedom of biological identification.

In order to achieve the above object, the identification device according to one embodiment of the present invention is an identification device that identifies a living body, and includes at least one transmitting antenna element that transmits a transmission signal to a predetermined range including the living body. Using the receiving antenna element of the receiving unit, the receiving signal including the reflected signal reflected by the living body, which is N receiving units arranged around the predetermined range, is used. The N receiving units each receive N receiving units for a predetermined period of time, and the N receiving units receive a receiving signal including a reflected signal transmitted from the transmitting antenna element to the target living body and reflected by the target living body. A memory that stores teacher signals, which are N reception signals obtained by receiving in advance, and N reception signals obtained by receiving the teacher signal and the N reception units. A circuit that calculates a plurality of correlation coefficients from the above, and determines that the living body and the target living body are the same when a predetermined correlation coefficient is included in a predetermined numerical range among the plurality of correlation coefficients. And.

It should be noted that these general or specific embodiments may be realized in a recording medium such as a system, method, integrated circuit, computer program or computer readable CD-ROM, system, method, integrated circuit, computer program. And any combination of recording media may be realized.

According to the identification device according to the present disclosure, the degree of freedom of biological identification can be improved, and biological identification can be effectively performed in a short time.

FIG. 1 is a configuration diagram showing an example of the identification device 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 showing an example of a teacher signal according to the first embodiment. FIG. 4 is a flowchart showing an example of the operation of the identification device according to the first embodiment. FIG. 5 is a flowchart showing an example of the determination process according to the first embodiment. FIG. 6 is a graph showing a conceptual diagram of the cumulative probability distribution of the correlation coefficient ρ. FIG. 7 is a diagram showing an environment used for the recognition test by the identification device in the first embodiment. FIG. 8 is a diagram showing a cumulative probability distribution of the correlation coefficient ρ obtained by the discrimination test. It is a figure which shows the identification result of the identification test performed based on the condition (X = 70 [%]) determined in FIG. FIG. 10 is a configuration diagram showing an example of the identification device according to the first modification of the first embodiment. FIG. 11 is a configuration diagram showing an example of the identification device according to the second embodiment. FIG. 12 is a block diagram showing a functional configuration of a circuit and a memory according to a second embodiment. FIG. 13 is a flowchart showing an example of the operation of the identification device according to the second embodiment.

(Knowledge that became the basis of the present invention)
The inventors have conducted a detailed study on the prior art for identifying living organisms using electromagnetic waves. As a result, in the methods of Patent Documents 1 and 2, a person sitting in the driver's seat of an automobile is irradiated with electromagnetic waves, the reflected wave from the person is measured, and the measured result is subjected to arithmetic processing. The biological identification is realized by measuring the heartbeat or the heart sound by this arithmetic processing and acquiring the time correlation of the measured heartbeat or the heart sound. However, there are many situations in which it is necessary to identify the living body other than the person sitting in the driver's seat. For example, the identification of the living body in various situations such as standing, sitting, sleeping, and walking is fully considered. Absent.

As a result of repeated research on the above problems, the inventors, in order to increase the application destinations of the identification device for identifying the living body, in order to relax the restriction between the antenna and the target living body for identifying the living body, We thought that it was necessary to improve the degree of freedom in the distance or positional relationship between the antenna and the target living body. Specifically, in order to increase the degree of freedom in the orientation of the target organism, that is, to enable identification regardless of the orientation of the target organism, a plurality of antennas around the target organism are used as a reference. It was found that it is installed at the position of the target living body in the direction of the target living body. Further, in order to increase the degree of freedom of the distance between the antenna and the target living body, the condition of the distance between the target living body and the antenna can be relaxed by positioning the target living body and performing distance correction using the result. I found that. Furthermore, it has been found that the distance between the target living body and the antenna weakens the reflected wave received by the antenna from the target living body, so that the measurement time is sufficiently lengthened to several tens of seconds or the like. In addition, by increasing the number of data to be acquired, acquiring a plurality of patterns of time correlation, arranging the results of the obtained multiple patterns of time correlation in descending order, and identifying the living body when the result is included in a predetermined region. We have found that it is possible to remove coincidences and noise components. The inventors came to the present invention by finding these.

That is, the identification device according to one aspect of the present invention is an identification device that identifies a living body, and includes at least one transmitting antenna element that transmits a transmission signal to a predetermined range including the living body and a periphery of the predetermined range. The N receiving units arranged so as to be surrounded by the living body receive the received signal including the reflected signal reflected by the living body by using the receiving antenna element of the receiving unit, each of which receives the received signal for a predetermined period of time. Obtained by the N receiving units receiving in advance a receiving signal including the N receiving units and the reflected signal transmitted from the transmitting antenna element to the target living body and reflected by the target living body. A plurality of correlation coefficients from a memory that stores teacher signals, which are N received signals, and N received signals obtained by receiving the teacher signal and the N receiving units. Is included, and when a predetermined correlation coefficient among the plurality of correlation coefficients is included in a predetermined numerical range, the living body and the target living body are determined to be the same.

According to this, the living body is identified by using the received signals received by the N receiving units arranged so as to surround the circumference of the predetermined range. Therefore, the living body can be identified with a small number of measurements regardless of the orientation of the living body. Therefore, the degree of freedom of biological identification can be improved, and biological identification can be effectively performed in a short time.

Further, the circuit further calculates a cumulative distribution function for the plurality of correlation coefficients, and among the plurality of correlation coefficients, the correlation coefficient having a cumulative probability of the first value in the cumulative distribution function is the first. When it is contained in two or more values or a third value or less, it may be determined that the living body and the target living body are the same.

Therefore, the biological identification can be performed more accurately.

Further, the circuit may calculate a plurality of correlation coefficients between the teacher signal and each of the N received signals as the plurality of correlation coefficients by a sliding correlation calculation.

Therefore, biological identification can be effectively performed.

Further, the circuit may further calculate the position of the living body in the predetermined range using the N received signals, and calculate the plurality of correlation coefficients using the position of the living body.

Therefore, it is possible to effectively identify the living body according to the position of the living body.

Further, the transmitting antenna element includes a plurality of transmitting antenna elements, and the plurality of transmitting antenna elements may be arranged at different locations from each other.

Therefore, it is possible to obtain a number of received signals multiplied by the number of a plurality of transmitting units. Therefore, the number of correlation coefficients can be increased, and the biological identification can be performed accurately in a short time.

Further, the transmitting antenna element includes N transmitting antenna elements, the N receiving antenna elements are each of the N transmitting antenna elements, and the circuit further comprises the N receiving signals. May be used to estimate the position of the living body in the predetermined range, and the plurality of correlation coefficients may be calculated using the position of the living body.

Therefore, the N transmitting antenna elements and the N receiving antenna elements can be used in combination, and the configuration of the identification device can be simplified.

Further, the teacher signal is the N reception signals obtained by the N reception units receiving the reception signals in advance for a period K times (K is 2 or more) of the predetermined period. May be good.

Therefore, the biological identification can be performed more accurately.

It should be noted that these general or specific embodiments may be realized in a recording medium such as a system, method, integrated circuit, computer program or computer readable CD-ROM, system, method, integrated circuit, computer program. And any combination of recording media may be realized.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that all of the embodiments described below show a preferred specific example of the present invention. Numerical values, shapes, materials, components, arrangement positions and connection forms of components, steps, order of steps, etc. shown in the following embodiments are examples, and are not intended to limit the present invention. Further, among the components in the following embodiments, the components not described in the independent claims indicating the highest level concept of the present invention will be described as arbitrary components constituting the more preferable form. In the present specification and the drawings, components having substantially the same functional configuration are designated by the same reference numerals, so that duplicate description will be omitted.

(Embodiment 1)
FIG. 1 is a configuration diagram showing an example of the configuration of the identification device according to the first embodiment.

As shown in FIG. 1, the identification device 10 includes a transmission unit 20, N reception units (reception units 30A to 30H in this embodiment), a circuit 40, and a memory 41. The identification device 10 transmits a transmission signal from the transmission unit 20 to a predetermined range A1 including the living body 50 such as a human, and receives a reception signal including the reflection signal reflected by the living body 50 by the reception units 30A to 30H. .. The identification device 10 identifies the living body 50 by processing the received signals received by the receiving units 30A to 30H by the circuit 40.

The transmitting unit 20 has at least one transmitting antenna element 21. The transmitting antenna element 21 transmits a transmission signal to a predetermined range A1. The transmission unit 20 may be arranged at a position around the predetermined range A1, that is, a position outside the predetermined range A1. Specifically, the transmitting antenna element 21 emits microwaves as a transmission signal to a living body 50 such as a human being. The transmitting antenna element 21 may transmit an unmodulated transmission signal, or may transmit a modulated transmission signal. When the modulation process is performed, the transmission unit 20 may include a circuit for performing the modulation process. The transmitting antenna element 21 is arranged at a position around the predetermined range A1. The predetermined range A1 is a space in a predetermined range for the identification device 10 to identify the living body 50.

Each of the receiving units 30A to 30H has one receiving antenna element 31A to 31H. The receiving antenna elements 31A to 31H receive a received signal including a reflected signal, which is a signal obtained by reflecting the transmitted signal from the transmitting unit 20 by the living body 50, for a predetermined period of time. The receiving units 30A to 30H are arranged in a circular shape at equal intervals, for example, in a state of surrounding the predetermined range A1. The receiving units 30A to 30H are composed of N pieces (8 pieces in the present embodiment).

Each of the receiving units 30A to 30H may frequency-convert the received signal and convert it into a low-frequency signal. Further, each of the receiving units 30A to 30H may perform demodulation processing on the received signal. Each of the receiving units 30A to 30H outputs a signal obtained by frequency conversion and / or demodulation processing to the circuit 40. Each of the receiving units 30A to 30H may include a circuit for processing the received signal.

The circuit 40 executes various processes for operating the identification device 10. The circuit 40 is composed of, 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, RAM (Random Access Memory).

The circuit 40 temporarily stores the signals acquired from each of the receiving units 30A to 30H in the volatile storage area for a predetermined period of time. The circuit 40 may temporarily store the phase and amplitude of the signal in a volatile storage area for a predetermined period of time. The circuit 40 may have a non-volatile storage area, and the signal may be temporarily stored in the non-volatile storage area for a predetermined period of time.

The circuit 40 may be configured by a dedicated circuit for performing various processes for operating the identification device 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), and is, for example, a ROM (Read Only Memory), a flash memory, an HDD (Hard Disk Drive), or the like. The memory 41 stores, for example, information used for various processes for operating the identification device 10.

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

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

The circuit 40 has a correlation coefficient calculation unit 410 and a determination unit 420.

The correlation coefficient calculation unit 410 compares the teacher signal 42 stored in the memory 41 with the N received signals obtained by the reception units 30A to 30H to receive a plurality of correlation coefficients. Is calculated. Here, the N received signals to be compared are signals stored in the storage area of the circuit 40 for a predetermined period.

Here, the teacher signal 42 stored in the memory 41 will be described.

FIG. 3 is a diagram showing an example of a teacher signal.

The teacher signal 42 receives a received signal including a reflected signal transmitted from the transmitting antenna element 21 to a known target living body such as a human being within a predetermined range A1 and reflected by the surface of the target living body. 30A to 30H are time response waveforms of N received signals obtained by receiving in advance. That is, as shown in FIG. 3, the teacher signal 42 is reflected in advance by the receiving units 30A to 30H for a period (measurement period of FIG. 3) that is K times (K is 2 or more) of a predetermined period for identifying the living body 50. These are N received signals obtained by receiving received signals including signals. The measurement period is, for example, 120 [s]. The teacher signal shown in FIG. 3 is an example of a received signal received by one receiving unit.

The teacher signal 42 may be acquired in advance for each of the plurality of known target organisms. In this case, each of the plurality of teacher signals 42 corresponding to the plurality of known target organisms is stored in the memory 41 in a state associated with the identification information for identifying the corresponding target organisms.

で表される相関係数を求める演算である。 Specifically, the correlation coefficient calculation unit 410 calculates a plurality of correlation coefficients between the teacher signal 42 and each of the N received signals by a sliding correlation calculation. The sliding correlation calculation dealt with here is

It is an operation to obtain the correlation coefficient represented by.

を算出する。ここで、τ_ｍａｘはスライディング相関演算を行う最大の時間差であり、生体活動の周期またはその数倍程度以上に設定すればよい。例えば呼吸の周期を３秒とすると、τ_ｍａｘは当該周期の３倍以上の１０秒程度に設定すればよい。既知の生体について事前に何度も教師信号を測定しており、メモリ４１が当該既知の生体についての複数の教師信号を記憶している場合、（式５）の演算を複数の教師信号に対して実施することによって、一度の観測で多数の相関係数ρを得てもよい。なお、ここで教師複素信号ベクトルＳ_ｌ（ｔ）と複素信号ベクトルＳ（ｔ）とは送信アンテナ素子２１と各受信アンテナ素子３１Ａ〜３１Ｈとの間の伝搬チャネル（伝達関数）であってもよい。 Here, S _l (t) is the l-th teacher complex signal vector, S (t) is the observed complex signal vector, and C is the cyclic permutation matrix. k (0 ≦ k ≦ M-1) is an exponential of the cyclic permutation matrix and corresponds to the orientation of the living body. That is, when C is multiplied once, the element of the observation signal vector S is cyclically shifted by one column, which is equivalent to the fact that the entire receiving antenna is rotated 360 / M degrees with respect to the center of the circle. ^{Ck rotates the receiving antenna by 360 k} / M degrees, because it can be recognized even when the living body faces an arbitrary direction. Further, τ is for considering the time difference between the observed received signal and the teacher signal. This is to utilize the fact that the waveform response caused by the living body is periodic, and by changing τ, it is possible to compare the received signal observed at an arbitrary timing with the teacher signal observed while sliding. it can. The correlation coefficient calculation unit 410 changes τ and k described above to obtain the maximum value of the correlation coefficient.

Is calculated. Here, τ _max is the maximum time difference for performing the sliding correlation calculation, and may be set to the cycle of biological activity or several times or more thereof. For example, assuming that the breathing cycle is 3 seconds, τ _max may be set to about 10 seconds, which is three times or more the cycle. When the teacher signal is measured many times in advance for a known living body and the memory 41 stores a plurality of teacher signals for the known living body, the calculation of (Equation 5) is performed on the plurality of teacher signals. By carrying out the above, a large number of correlation coefficients ρ may be obtained in one observation. Here, the teacher complex signal vector S _l (t) and the complex signal vector S (t) may be propagation channels (transfer functions) between the transmitting antenna element 21 and the receiving antenna elements 31A to 31H. ..

The determination unit 420 determines whether or not a plurality of correlation coefficients calculated by the correlation coefficient calculation unit 410 are included in a predetermined numerical range. When the predetermined correlation coefficient among the plurality of correlation coefficients is included in the predetermined numerical range, the determination unit 420 determines that the living body 50 and the target living body are the same.

Specifically, the determination unit 420 calculates a cumulative distribution function for a plurality of correlation coefficients. The determination unit 420 determines whether or not the correlation coefficient having the first value of the cumulative probability in the calculated cumulative distribution function is included in the numerical range of the second value or more among the plurality of correlation coefficients. Then, when the determination unit 420 determines as a result of the determination that the correlation coefficient in which the cumulative probability takes the first value in the calculated cumulative distribution function is included in the numerical range of the second value or more, the living body 50 and the target living body Is determined to be the same.

The determination unit 420 determines that the living body 50 and the target living body are the same when the correlation coefficient in which the cumulative probability takes the first value in the calculated cumulative distribution function is included in the numerical range of the second value or more. However, the criterion for judgment is not limited to the numerical range of the second value or more. The determination unit 420 may determine that the living body 50 and the target living body are the same when the correlation coefficient is included in the numerical range of the second value or more and the third value or less. Further, the determination unit 420 may determine that the living body 50 and the target living body are the same when the correlation coefficient is included in the numerical range of the third value or less.

When a plurality of teacher signals 42 acquired in advance for each of the plurality of known target organisms are stored in the memory 41, in the circuit 40, each of the teacher signals 42 corresponding to each of the plurality of target organisms is stored. Is processed. Thereby, the circuit 40 identifies the living body 50 as the target living body corresponding to the teacher signal 42 determined to be the same as the living body 50.

FIG. 4 is a flowchart showing an example of the operation of the identification device according to the first embodiment.

In the identification device 10, the transmitting antenna element 21 transmits a transmission signal to the predetermined range A1 with the living body 50 arranged in the predetermined range A1 (S11).

The receiving units 30A to 30H use the receiving antenna elements 31A to 31H, respectively, to receive the received signal including the reflected signal reflected by the living body 50 for a predetermined period (S12).

The circuit 40 reads the teacher signal 42 from the memory 41, and calculates a plurality of correlation coefficients from the read teacher signal and N received signals (S13). Specifically, the circuit 40 obtains the correlation coefficient of the complex signal vector S (t) obtained by processing the obtained received signal by the procedures of (Equation 1) to (Equation 5). _{Here, L teacher signal groups [S 1} (t), obtained by performing the work of observing the teacher complex signal vector S _l (t) for a certain period of time L times in advance. .. .. , _SL (t)] is stored in the memory 41. In this case, since the correlation coefficient is obtained by comparing the L teacher signal group with the N received signals, the number of obtained correlation coefficients is L × N.

Next, the circuit 40 determines that the living body 50 and the target living body are the same when a predetermined correlation coefficient is included in the predetermined numerical range among the plurality of calculated correlation coefficients (S14).

Next, the determination process in step S14 will be specifically described.

FIG. 5 is a flowchart showing an example of the determination process according to the first embodiment.

In the determination process, the determination unit 420 calculates the cumulative probability distribution of the obtained plurality of correlation coefficients (S21).

The determination unit 420 calculates the correlation coefficient ρ (X) in which the cumulative probability is the X% value as the first value in the calculated cumulative probability distribution among the plurality of correlation coefficients (S22). Here, the determination unit 420 sets the X% value as the determination criterion as a cumulative probability distribution obtained in the same living body as the target living body of the teacher signal and a cumulative probability distribution obtained in a living body different from the target living body of the teacher signal. By setting the value so that the difference between the two is sufficiently large, it is possible to improve the identification rate described later. When the value at which the above difference becomes sufficiently large is unknown, the determination unit 420 may set the X% value to, for example, the median value (X = 50%).

Next, the determination unit 420 sets _{a threshold value ρ min} as a second value in advance in order to perform identification, _{and determines whether or not ρ min} ≤ ρ (X) is satisfied (S23). .. _{When the determination unit 420 satisfies ρ min} ≤ ρ (X) (Yes in S23), the determination unit 420 determines that the living body 50 is the same as the target living body (S24). On the other hand, when the determination unit 420 _{does not satisfy ρ min} ≤ ρ (X), that is, when ρ _min > ρ (X) (No in S23), the determination unit 420 determines that the living body 50 is different from the target living body (S25). ). The threshold value ρ _{min needs to be set so as to satisfy ρ min} ≤ ρ (X) when the teacher signal is the same as the target organism, but if it is set to a value too low, the target organism is Since the false positive rate for identifying different living organisms as the same living body increases, it is necessary to set an appropriate value.

FIG. 6 is a graph showing a conceptual diagram of the cumulative probability distribution of the correlation coefficient ρ. Specifically, in FIG. 6, the cumulative probability distribution when the organism is the same as the target organism of the teacher signal is shown by a solid line graph, and the cumulative probability distribution when the organism is different from the target organism of the teacher signal is shown. It is shown in a dashed graph. Since the correlation coefficient between the same living organisms tends to be high, there is a difference in ρ (X) of both distributions shown by the solid line and the broken line. If such a difference in distribution is known through a prior experiment or the like, the determination unit 420 can perform the determination process using the _{threshold value ρ min, which has few false recognitions and can obtain a high recognition rate.} The determination unit 420 can be further identified by using _{the threshold value ρ min} set appropriately in this way.

Next, the identification test conducted for clarifying the effectiveness of the biological identification by the identification device 10 in the first embodiment will be described.

FIG. 7 is a diagram showing an environment used for the identification test by the identification device in the first embodiment.

As shown in FIG. 7, in the identification test, one transmitter corresponding to the transmitting unit 20 and eight receivers (receiving antennas) corresponding to the receiving units 30A to 30H were used. The eight receivers are arranged in a circle with a radius of 0.5 m and an interval of 45 degrees around the living body. Here, the transmitting antenna element is a one-element square patch antenna, and the eight receiving antenna elements of the eight receivers are each a square patch antenna. The height from the floor surface to the position where the receiving antenna element is installed is 0.9 m. The transmitting antenna element is arranged directly above one wavelength of the microwave of the first receiving antenna element.

FIG. 8 is a diagram showing a cumulative probability distribution of the correlation coefficient ρ obtained by the discrimination test.

Here, the teacher signal is the result of performing the measurement five times in advance. Moreover, the number of observations for identification is one. The predetermined period for identification is T = 10 seconds.

A relatively high correlation coefficient was observed when the organism was the same as the target organism, but when the organism was different from the target organism, the correlation coefficient was higher than when the organism was the same as the target organism. It turns out to be low. Based on the results of this experiment, the first value used as a reference for comparing the correlation coefficients was set to X = 70 [%], which has a relatively large difference in distribution.

FIG. 9 is a diagram showing the results of a discrimination test performed based on the conditions (X = 70 [%]) determined in FIG. In FIG. 9, when the threshold value ρ _min is changed, the probability that the organism can be correctly identified as the same organism as the target organism (hereinafter, also referred to as “recognition rate”) is shown by a solid line graph, and the target organism is shown. The probability of accidentally identifying a living body different from the above (hereinafter, also referred to as “misrecognition rate”) is shown by a broken line graph. The erroneous recognition rate is the probability when it is determined that the organism is the same as the target organism in the determination process for the organism different from the target organism.

From the broken line graph shown in FIG. 9, it can be seen that the false recognition rate decreases as the _{threshold value ρ min is increased.} Further, it was clarified that the false recognition rate can be set to 0% and the recognition rate can be set to 90% by setting the threshold value ρ _min to ρ _{min ≥ 0.86.}

According to the identification device 10 according to the present embodiment, biometric identification is performed using the received signals received by the N receiving units 30A to 30H arranged so as to surround the periphery of the predetermined range A1. Therefore, the received signal can be acquired from a plurality of different angles, and the biological identification can be performed with a small number of measurements. Therefore, the degree of freedom of biological identification can be improved, and biological identification can be effectively performed in a short time.

Further, the identification device 10 according to the present embodiment identifies a living body such as a human by using a wireless signal such as a microwave. In this way, since a living body such as a human can be identified without performing image analysis on the image captured by the camera, it is possible to identify the human while protecting the privacy of the human.

(Modification 1 of Embodiment 1)
The identification device 10 according to the first embodiment is configured to include one transmitting unit 20 and N receiving units 30A to 30H, but the present invention is not limited to this. For example, as shown in FIG. 10, an identification device 10A including N transmission / reception units 60A to 60H (8 in this modification) may be adopted.

FIG. 10 is a configuration diagram showing an example of the identification device in the first modification.

The transmission / reception units 60A to 60H have N receiving antenna elements 31A to 31H. Each of the N receiving antenna elements 31A to 31H also functions as N transmitting antenna elements. Since the configurations of the circuit 40 and the memory 41 are the same as the configurations of the identification device 10 of the first embodiment, the description thereof will be omitted.

In this case, each of the transmission / reception units 60A to 60H selectively functions one of the transmission unit and the reception unit. That is, for example, one of the transmission / reception units 60A to 60H functions as a transmission unit, and the other plurality of transmission / reception units function as reception units to acquire a plurality of reception signals. Further, by sequentially switching the transmission / reception units that function as the transmission units, it is possible to acquire a plurality of reception signals by the transmission signals transmitted from the plurality of transmission / reception units 60A to 60H.

Needless to say, this configuration makes it possible to efficiently acquire the teacher signal and the received signal in a short time.

(Modification 2 of Embodiment 1)
The identification device 10A of the first modification has a configuration in which a transmission / reception unit that also serves as a transmission unit and a reception unit is provided, but it does not have to be shared. That is, the identification device may be configured to include a plurality of transmission units and N separate reception units different from the plurality of transmission units. The plurality of transmitters are arranged around the predetermined range A1, that is, at different positions outside the predetermined range A1.

(Embodiment 2)
In the identification devices 10 and 10A according to the first embodiment and the first and second modifications thereof, the position of the living body 50 in the predetermined range A1 is not considered, but the identification device 10B according to the second embodiment is not considered. Then, the position of the living body 50 in the predetermined range A1 may be detected and the identification may be performed using the position.

FIG. 11 is a configuration diagram showing an example of the identification device according to the second embodiment.

As shown in FIG. 11, the identification device 10B includes a transmission unit 20B, reception units 70A and 70B, a circuit 40B, and a memory 41. Since the configuration of the memory 41 is the same as that of the first embodiment, the description thereof will be omitted.

The transmission unit 20B has n transmission antenna elements 21B (n is a natural number of 2 or more). The transmission unit 20B has an array antenna in which n transmission antenna elements 21B are arranged side by side in a first predetermined direction on a horizontal plane. Each of the n transmitting antenna elements 21B transmits a transmission signal to a predetermined range A1. That is, the transmission unit 20B transmits n transmission signals from different n positions to a predetermined range A1.

Each of the n transmitting antenna elements 21B may sequentially switch and transmit a modulated signal or an unmodulated signal. In this way, by setting the transmission signals transmitted from the n transmission antenna elements 21B to different transmission signals for each of the n transmission antenna elements 21B, the transmission signal received by the receiving unit 70A is transmitted. The antenna element 21B can be specified. As described above, the transmission unit 20B may include a circuit for performing the modulation process.

The receiving unit 70A has m (m is a natural number of 2 or more) receiving antenna elements 71A. The receiving unit 70A has an array antenna in which m receiving antenna elements 71A are arranged side by side in a second predetermined direction on a horizontal plane. Each of the m receiving antenna elements 71A receives n received signals including a reflected signal which is a signal reflected by the living body 50 among the n transmitted signals. The receiving unit 70A frequency-converts the received signal composed of microwaves and converts it into a low-frequency signal. The receiving unit 70A outputs the signal obtained by converting it into a low frequency signal to the circuit 40B. That is, the receiving unit 70A may include a circuit for processing the received signal.

The receiving unit 70B has one receiving antenna element 71B. Since the receiving unit 70B has the same configuration as one of the receiving units 30A to 30H of the first embodiment, the description thereof will be omitted. The receiving unit 70B is arranged at a position opposite to the position where the transmitting unit 20B and the receiving unit 70A are arranged with the predetermined range A1 interposed therebetween. That is, the receiving unit 70A and the receiving unit 70B are arranged so as to surround the predetermined range A1.

Since the hardware configuration of the circuit 40B is the same as that of the circuit 40 of the first embodiment, the description thereof will be omitted.

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

FIG. 12 is a block diagram showing a functional configuration of a circuit and a memory according to a second embodiment.

The circuit 40B includes a correlation coefficient calculation unit 410, a determination unit 420, a complex transfer function calculation unit 430, a biological component calculation unit 440, a position estimation processing unit 450, and a signal correction unit 460. The circuit 40B is different from the circuit 40 of the first embodiment in that it further includes a complex transfer function calculation unit 430, a biological component calculation unit 440, a position estimation processing unit 450, and a signal correction unit 460. Therefore, these configurations will be described.

The complex transfer function calculation unit 430 calculates the complex transfer function from the received signal converted into the low frequency signal. The complex transfer function represents the propagation loss and phase rotation between each transmitting antenna element 21B and each receiving antenna element 71A. The complex transfer function is a complex matrix having a component of m × n when the number of transmitting antenna elements is n and the number of receiving antenna elements is m. Hereinafter, this complex matrix will be referred to as a complex transfer function matrix. The estimated complex transfer function matrix is output to the biological component calculation unit 440. That is, the complex transfer function calculation unit 430 has n transmission antenna elements 21B and m reception antenna elements from each of the plurality of reception signals received in each of the m reception antenna elements 71A in a predetermined period. A first matrix of n × m is calculated, which is composed of each complex transfer function showing the propagation characteristics with each of 71A.

The biological component calculation unit 440 separates the complex transfer function matrix component obtained from the received signal passing through the living body 50 and the complex transfer function matrix component obtained from the received signal not passing through the living body 50. The component that has passed through the living body 50 is a component that fluctuates with time due to biological activity. Therefore, the component that has passed through the living body 50 is, for example, a component other than the direct current from the component obtained by Fourier transforming the component of the complex transfer function matrix in the time direction, assuming that the components other than the living body 50 are stationary. Can be extracted by taking out. Further, the component that has 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 does not exist in the predetermined range A1 exceeds a predetermined threshold value. .. In this way, the biological component calculation unit 440 calculates the extracted complex transfer function matrix component as a biological component by extracting the complex transfer function matrix component obtained from the received signal including the reflected signal passing through the living body 50. .. That is, the biological component calculation unit 440 extracts the second matrix corresponding to the predetermined frequency range in the first matrix, and thereby, the component affected by the vital activity including at least one of the respiration, heartbeat, and body movement of the living body. The second matrix corresponding to is extracted. The predetermined frequency range is, for example, a frequency derived from vital activity including at least one of the above-mentioned respiration, heartbeat, and body movement of a living body. The predetermined frequency range is, for example, a frequency in the range of 0.1 Hz or more and 3 Hz or less. This makes it possible to extract biological components affected by vital activity of 50 parts of the living body due to the movement of the heart, lungs, diaphragm, and internal organs, or vital activity of hands, feet, and the like. The parts of the living body 50 due to the movement of the heart, lungs, diaphragm, and internal organs are, for example, the epigastrium of a human being.

Here, the biological component is a matrix having a component of m × n, and is extracted from the complex transfer function obtained from the received signal observed by the receiving unit 70A in a predetermined period. Therefore, it is assumed that the biological component has frequency response or time response information. The predetermined period is approximately half the period of at least one cycle of respiration, heartbeat, and body movement of the living body.

The biological component calculated by the biological component calculation unit 440 is output to the position estimation processing unit 450. The position estimation processing unit 450 estimates the position of the living body 50 using the calculated biological components. That is, the position estimation processing unit 450 estimates the position of the living body 50 in the predetermined range A1 by estimating the position of the living body 50 with respect to the identification device 10B using the second matrix. For position estimation, both the departure angle θ _T from the transmission unit 20B and the arrival angle θ _R to the reception unit 70A are estimated, and the estimated departure angle θ _T and arrival angle θ _R are stored in the memory 41 in advance. The position of the living body 50 is estimated by the trigonometry from the stored positions of the transmitting unit 20B and the receiving unit 70A.

The angle formed by the first reference direction arbitrarily set for the transmitting unit 20B and the first living body direction, which is the direction from the transmitting unit 20B to the living body 50, is defined as the starting angle θ _T. Similarly, a second reference direction which is arbitrarily set with respect to the receiving portion 70A, the arrival angle theta _R an angle from the receiving portion 70A and the second living direction is the direction of the living body 50. The first reference direction, the first biological direction, the second reference direction, and the second biological direction are directions on the horizontal plane.

The signal correction unit 460 has the transmitting antenna element 21B and the receiving antenna element 71A for each of the plurality of received signals received by the receiving units 70A and 70B according to the position of the living body 50 estimated by the position estimation processing unit 450. The correction is performed in consideration of the distance between 71B and the living body 50.

The correlation coefficient calculation unit 410 compares the teacher signal 42 stored in the memory 41 with the plurality of correction signals obtained by the correction by the signal correction unit 460 to obtain a plurality of correlation coefficients. calculate. The correlation coefficient calculation unit 410 is different from the first embodiment only in that a plurality of correction signals are used instead of the plurality of received signals, and the processing to be executed is the same as that of the first embodiment. Is.

FIG. 13 is a flowchart showing an example of the operation of the identification device according to the second embodiment.

In the identification device 10, the transmitting antenna element 21B transmits n transmission signals to the predetermined range A1 with the living body 50 arranged in the predetermined range A1 (S11a).

The receiving units 70A and 70B use the receiving antenna elements 71A and 71B, respectively, to provide n reception signals including a plurality of reflected signals transmitted by the transmitting unit 20B and reflected by the living body 50. Is received (S12a).

In the circuit 40B, from each of the n received signals received in each of the m receiving antenna elements 71A in a predetermined period, between each of the n transmitting antenna elements 21B and each of the m receiving antenna elements 71A. A first matrix of n × m is calculated with each complex transfer function showing the propagation characteristics of the above as a component (S31).

The circuit 40B 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. Two matrices are extracted (S32).

The circuit 40B estimates the position of the living body 50 with respect to the identification device 10B using the second matrix (S33).

The circuit 40B corrects each of the plurality of received signals received by the receiving units 70A and 70B according to the estimated position of the living body 50 (S34).

The circuit 40B performs steps S13 and S14 described in the first embodiment, and ends the process.

According to the identification device 10B according to the present embodiment, even when the living body 50 is moving within the predetermined range A1, the position of the moving living body 50 is positioned and received based on the measured coordinates. Since the distance and direction between the part and the living body are calculated and the received signal is corrected, the living body 50 that is moving can also be identified.

(Modified Example of Embodiment 2)
In the second embodiment, the position of the living body 50 within the predetermined range A1 is estimated by using n received signals including a plurality of reflected signals reflected by the living body 50 as the transmitting signal transmitted by the transmitting unit 20B. However, it is not limited to this. For example, the position of the living body 50 within the predetermined range A1 may be detected by using an existing device such as a biological radar or a camera capable of positioning the living body.

In each of the above embodiments, each component may be configured by dedicated hardware or may be realized by executing a software program suitable for each component. Each component may be realized by a program execution unit such as a CPU or a processor reading and executing a software program recorded on a recording medium such as a hard disk or a semiconductor memory. Here, the software that realizes the identification device and the like of each of the above embodiments is the following program.

That is, this program is an identification method for identifying a living body by an identification device including at least one transmitting antenna element, N receiving units each having a receiving antenna element, a memory, and a circuit in a computer. Then, the transmission signal is transmitted to a predetermined range including the living body by using the transmitting antenna element, and the transmitting signal is reflected by the living body by using the receiving antenna element possessed by each of the N receiving units. Each of the received signals including the reflected signal is received for a predetermined period, and the transmitted signal transmitted from the transmitting antenna element to the target living body receives the reflected signal reflected by the target living body in advance by the N receiving units. The teacher signal, which is the N received signals obtained by the above, is read from the memory, and a plurality of correlation coefficients are obtained from the read teacher signal and the N received signals received by the N receiving units. Is calculated, and when a predetermined correlation coefficient is included in a predetermined numerical range among the calculated plurality of correlation coefficients, an identification method for determining that the living body and the target living body are the same is executed.

Although the identification devices 10, 10A, and 10B according to one or more aspects of the present invention have been described above based on the embodiments, the present invention is not limited to the embodiments. As long as it does not deviate from the gist of the present invention, one or more of the present embodiments may be modified by those skilled in the art, or may be constructed by combining components in different embodiments. It may be included within the scope of the embodiment.

The present invention can be used for an identification device that identifies a living body using a wireless signal, and is particularly used for a biological identification device mounted on a home appliance that controls according to the living body, a monitoring device that detects the invasion of the living body, and the like. it can.

10, 10A, 10B Identification device 20, 20B Transmitter 21, 21B Transmitter antenna element 30A to 30H, 70A, 70B Receiver 31A to 31H, 71A, 71B Receiver antenna element 40, 40B Circuit 41 Memory 42 Teacher signal 50 Living body 60A to 60H Transmission / reception unit 410 Correlation coefficient calculation unit 420 Judgment unit 430 Complex transfer function calculation unit 440 Biological component calculation unit 450 Position estimation processing unit 460 Signal correction unit

Claims (8)

An identification device that identifies living organisms
At least one transmitting antenna element that transmits a transmission signal to a predetermined range including the living body, and
A reception unit having N reception units (N is 2 or more) arranged around the predetermined range and including a reflection signal in which the transmission signal is reflected by the living body. Using antenna elements, N receivers, each of which receives for a predetermined period of time,
N reception signals obtained by the N reception units receiving in advance a reception signal including a reflection signal reflected by the target living body as a transmission signal transmitted from the transmission antenna element to the target living body. The memory that stores the teacher signal, which is
Plurality by comparing the N-number of the received signal in the predetermined period obtained by receiving the pre-Symbol N reception portion, a signal of the predetermined period of the received signal stored as the teacher signal When a predetermined correlation coefficient among the plurality of correlation coefficients is included in a predetermined numerical range, it is determined that the living body and the target living body are the same. With,
Identification device. The circuit
Further, a cumulative distribution function for the plurality of correlation coefficients is calculated.
When the correlation coefficient having the first value of the cumulative probability in the cumulative distribution function among the plurality of correlation coefficients is included in the second value or more or the third value or less, the living body and the target living body are included. Judge that is the same,
The identification device according to claim 1. The circuit calculates a plurality of correlation coefficients between the teacher signal and each of the N received signals as the plurality of correlation coefficients by a sliding correlation calculation.
The identification device according to claim 1 or 2. The circuit
Further, the position of the living body in the predetermined range is calculated using the N received signals.
Using the position of the living body, the N received signals in the predetermined period are corrected, and the received signals are corrected.
The plurality of correlation coefficients are calculated by comparing the corrected N received signals in the predetermined period with the received signals stored as the teacher signals in the predetermined period.
The identification device according to any one of claims 1 to 3. The transmitting antenna element includes a plurality of transmitting antenna elements.
The plurality of transmitting antenna elements are arranged at different locations from each other.
The identification device according to any one of claims 1 to 4. The transmitting antenna element includes N transmitting antenna elements.
The N receiving antenna elements are the N transmitting antenna elements, respectively.
The circuit further
Using the N received signals, the position of the living body in the predetermined range is estimated.
Using the position of the living body, the N received signals in the predetermined period are corrected, and the received signals are corrected.
The plurality of correlation coefficients are calculated by comparing the corrected N received signals in the predetermined period with the received signals stored as the teacher signals in the predetermined period.
The identification device according to any one of claims 1 to 4. The teacher signal is the N reception signals obtained by the N reception units receiving the reception signals in advance for a period K times (K is 2 or more) of the predetermined period.
The identification device according to any one of claims 1 to 6. A method for identifying a living body by an identification device including at least one transmitting antenna element, N receiving units (N is 2 or more) each having a receiving antenna element, a memory, and a circuit.
Using the transmitting antenna element, a transmission signal is transmitted to a predetermined range including the living body, and the transmission signal is transmitted.
Using the receiving antenna element of each of the N receiving units, each receives a receiving signal including a reflected signal reflected by the living body for a predetermined period of time.
The teacher signal which is the N reception signals obtained by the N reception units receiving the reflected signal reflected by the target living body in advance from the transmission signal transmitted from the transmission antenna element to the target living body. From the memory,
A plurality of correlation coefficients by comparing the signal of the predetermined period of pre-Symbol the N and N of the received signal in the predetermined period received by the receiving unit, the stored received signal as the teacher signal Is calculated and
When a predetermined correlation coefficient among the calculated plurality of correlation coefficients is included in a predetermined numerical range, it is determined that the living body and the target living body are the same.
Identification method.

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