JP7552940B2 - Judging device - Google Patents

Description

The present invention relates to a determination device and a determination program for determining the presence or absence of a person in a specific area.

A known example of an invention related to a conventional determination device is the transmission device described in Patent Document 1. This transmission device senses the surroundings using electromagnetic waves. Specifically, the transmission device detects pedestrians and vehicles using electromagnetic waves.

International Publication No. 2020/122220

However, in the field of the transmitting device described in Patent Document 1, there is a demand for new sensing technology that can sense specific areas, such as the interior of an automobile.

Therefore, the object of the present invention is to provide a determination device and a determination program equipped with a new sensing technology for sensing a specific area, such as the interior of a car.

The present inventor has studied a new sensing technology for sensing a specific area such as the interior of a car. The present inventor has focused on channel state information. The channel state information is information indicating the state of the transmission path of the electromagnetic wave. By using this channel state information, detailed information on the transmission path of the electromagnetic wave can be obtained. Therefore, the present inventor thought that by using the channel state information to sense a specific area such as the interior of a car (hereinafter referred to as the first area), information related to the position of an object in the first area can be obtained. Here, the present inventor noticed that when a person moves or breathes in the first area, the state of the transmission path of the electromagnetic wave changes. In other words, the present inventor noticed that when a person moves or breathes in the first area, the channel state information changes. Therefore, the present inventor noticed that the presence or absence of a person in the first area can be determined by using the channel state information.

However, the sensing technology using the channel state information has high sensing performance. Therefore, the inventor of the present application noticed that the channel state information also changes when a person is present in the second area located near the first area. Specifically, the inventor of the present application noticed that the channel state information changes when a person moves or breathes in the second area located near the first area. Therefore, the inventor of the present application noticed that the sensing technology using the channel state information can determine the presence or absence of a person in the second area adjacent to the first area, in addition to determining the presence or absence of a person in the first area. As a result, the inventor of the present application came up with a new sensing technology in which a single determination device performs a determination related to the position of an object in the first area and a determination of the presence or absence of a person in the second area adjacent to the first area.

The determination device according to the present invention comprises:
A determination device used in a transmission/reception system in which first to N-th subcarrier signals transmitted by electromagnetic waves from a first to T-th transmission antennas are received by a first to R-th reception antennas, the determination device comprising:
N, T, and R are integers of 1 or more;
the first transmitting antenna through the T transmitting antenna and the first receiving antenna through the R receiving antenna are arranged in a first area,
The channel state information is information indicating a state of a transmission path of the electromagnetic wave between the first transmitting antenna to the T transmitting antenna and the first receiving antenna to the R receiving antenna,
The determination device includes:
an acquisition step of acquiring the channel state information calculated based on signals of the first subcarrier through the Nth subcarrier received by the first receiving antenna through the R receiving antenna;
a determination step of performing a determination related to a position of an object in the first region and a determination of the presence or absence of a person in a second region adjacent to the first region based on the channel state information acquired in the acquisition step;
Execute.

The determination program according to the present invention comprises:
A determination program executed in a determination device of a transmission/reception system in which first to N-th subcarrier signals transmitted by electromagnetic waves from a first to T-th transmission antennas are received by a first to R-th reception antennas, the determination program comprising:
N, T, and R are integers of 1 or more;
the first transmitting antenna through the T transmitting antenna and the first receiving antenna through the R receiving antenna are arranged in a first area,
The channel state information is information indicating a state of a transmission path of the electromagnetic wave between the first transmitting antenna to the T transmitting antenna and the first receiving antenna to the R receiving antenna,
The determination program includes:
an acquisition step of acquiring the channel state information calculated based on signals of the first subcarrier through the Nth subcarrier received by the first receiving antenna through the R receiving antenna;
a determination step of determining whether or not a person is present in a second area adjacent to the first area, based on the channel state information acquired in the acquisition step;
The determination device is caused to execute the above.

The determination device of the present invention can provide a determination device equipped with new sensing technology for sensing specific areas, such as the interior of a car.

FIG. 1 is a block diagram of a transmission/reception system 1. FIG. 2 is a perspective view showing the first area A1 and the second area A2. FIG. 3 is a perspective view showing a first area A1, a second area A2, and a person M2 located in the second area A2. FIG. 4 is a top view showing a first area A1, a second area A2, a person M1 located in the first area A1, and a person M2 located in the second area A2. FIG. 5 is a graph showing the amplitude and phase of hmn when a person M1 located in the first area A1 moves. FIG. 6 is a graph showing the amplitude and phase of hmn during breathing of a person M1 located in the first area A1. FIG. 7 is a graph showing the amplitude of hmn during breathing of a person M2 located in the second area A2. FIG. 8 is a graph showing the amplitude of hmn when a person M2 is not present in the second area A2. FIG. 9 is a graph showing the results of FFT processing of the waveform showing the amplitude of hmn in FIG. FIG. 10 is a graph showing the results of FFT processing of the waveform showing the amplitude of hmn in FIG. FIG. 11 is a flowchart showing the operation executed by the determination device 14. FIG. 12 is a block diagram of the transmission/reception system 1a.

(Embodiment)
Hereinafter, a structure of a transmission/reception system 1 including a determination device 14 according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of the transmission/reception system 1. FIG. 2 is a perspective view showing a first area A1 and a second area A2. FIG. 3 is a perspective view showing the first area A1, the second area A2, and a person M2 located in the second area A2. FIG. 4 is a top view showing the first area A1, the second area A2, the person M1 located in the first area A1, and the person M2 located in the second area A2. In this embodiment, the first area A1 is a cabin of a vehicle. In this embodiment, the second area A2 is outside the vehicle. In this embodiment, the second area A2 is adjacent to the first area A1. In this embodiment, the vehicle is an automobile. The vehicle has a window.

The transmission/reception system 1 is used in a wireless LAN (Local Area Network) of an automobile. The wireless LAN system is, for example, Wi-Fi (registered trademark). The transmission/reception system 1 includes a transmission device 9, a first transmission antenna 10-1 through a T-th transmission antenna 10-T, a reception device 11, a first reception antenna 12-1 through an R-th reception antenna 12-R, and a determination device 14. T and R are integers equal to or greater than 1. In this manner, the determination device 14 is used in the transmission/reception system. The transmission device 9, the first transmission antenna 10-1 through the T-th transmission antenna 10-T, the reception device 11, the first reception antenna 12-1 through the R-th reception antenna 12-R, and the determination device 14 are arranged in a first area A1 (cabin of the vehicle) as shown in Figures 1 to 3. The transmission device 9 and the reception device 11 are access points of the wireless LAN.

The transmitting device 9 generates a first transmission signal through a Tth transmission signal. The transmitting device 9 transmits the first transmission signal through the Tth transmission signal, respectively, from the first transmission antenna 10-1 through the Tth transmission antenna 10-T by electromagnetic waves. At this time, each of the first transmission signal through the Tth transmission signal includes a first subcarrier signal through an Nth subcarrier signal. N is an integer equal to or greater than 1. The first subcarrier signal through the Nth subcarrier signal are carrier waves used in OFDM (Orthogonal Frequency Division Multiplexing). The first subcarrier signal through the Nth subcarrier signal have different frequencies that are orthogonal to each other.

The first through Tth transmission signals are transmitted by repeated reflection. Then, the first through Rth reception antennas 12-1 through 12-R receive the first through Rth reception signals. Each of the first through Rth reception signals includes a first subcarrier signal through an Nth subcarrier signal. Each of the first through Rth reception signals includes the first through Tth transmission signals as components. As described above, the transmission/reception system 1 is a system that receives the first through Nth subcarrier signals transmitted by electromagnetic waves from the first transmission antenna 10-1 through the Tth transmission antenna 10-T at the first reception antenna 12-1 through the Rth reception antenna 12-R.

The determination device 14 is communicatively connected to the receiving device 11. The determination device 14 is a processing circuit such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit). The determination device 14 calculates channel state information (CSI: Channel State Information) based on the first to Rth received signals of the first to Nth subcarriers received by the first receiving antenna 12-1 to the Rth receiving antenna 12-R. The channel state information is information indicating the state of the transmission path of the electromagnetic wave between the first transmitting antenna 10-1 to the Tth transmitting antenna 10-T and the first receiving antenna 12-1 to the Rth receiving antenna 12-R. The channel state information is described below.

The first through Tth transmission signals transmitted by the first transmitting antenna 10-1 through the Tth transmitting antenna 10-T are complex numbers x1 through xT, respectively. The first through Rth reception signals received by the first receiving antenna 12-1 through the Rth receiving antenna 12-R are complex numbers y1 through yR, respectively. In this case, x1 through xT and y1 through yR satisfy equations (1) through (5).

i is an integer between 1 and N, inclusive.
m is an integer of 1 or more and R or less.
n is an integer of 1 or more and T or less.
||hmn|| is the amplitude of hmn.
∠hmn is the phase of hmn.
ni is the noise vector.

Hi is the channel state information of the i-th subcarrier. Furthermore, the component hmn contained in Hi indicates the state of the electromagnetic wave transmission path between the m-th transmitting antenna 10-m and the n-th receiving antenna 12-n in the i-th subcarrier. Here, the calculation of the channel state information Hi of the i-th subcarrier is explained.

The transmitting device 9 transmits the first transmission signal x1 through the Tth transmission signal xT having a predetermined waveform of the i-th subcarrier from the first transmitting antenna 10-1 through the Tth transmitting antenna 10-T. The first receiving antenna 12-1 through the Rth receiving antenna 12-R receive the first receiving signal y1 through the Rth receiving signal yR of the i-th subcarrier. As a result, the determining device 14 obtains the first receiving signal y1 through the Rth receiving signal yR of the i-th subcarrier.

As described above, the first transmission signal x1 through the Tth transmission signal xT of the i-th subcarrier transmitted by the first transmitting antenna 10-1 through the Tth transmitting antenna 10-T are signals having a predetermined waveform. Therefore, if the determination device 14 removes noise ni from the first receiving antenna 12-1 through the Rth receiving antenna 12-R of the i-th subcarrier, it can calculate the channel state information Hi of the i-th subcarrier using equation (1). The determination device 14 performs this calculation for the first subcarrier through the Nth subcarrier. Through the above operations, the determination device 14 can calculate the channel state information H1 through HN.

The time when a person is breathing and moving is called the time when the person is moving. The time when a person is breathing and not moving is called the time when the person is breathing. Figure 5 is a graph showing the amplitude and phase of hmn when person M1 located in the first area A1 is moving. Figure 6 is a graph showing the amplitude and phase of hmn when person M1 located in the first area A1 is breathing. The vertical axis of Figures 5 and 6 is amplitude or phase. The horizontal axis of Figures 5 and 6 is time. Figures 5 and 6 show the experimental results when person M1 is seated in the rear seat of a car.

The state of reflection of the electromagnetic wave in the first area A1 changes depending on the presence or absence of the person M1 in the first area A1 and the position of the person M1. Furthermore, the state of reflection of the electromagnetic wave in the first area A1 changes depending on the presence or absence of the movement of the person M1 in the first area A1. As described above, the channel state information Hi is information indicating the state of the transmission path of the electromagnetic wave between the first transmitting antenna 10-1 to the Tth transmitting antenna 10-T and the first receiving antenna 12-1 to the Rth receiving antenna 12-R. Therefore, the channel state information Hi changes depending on the presence or absence of the movement of the person M1 in the first area A1. The channel state information Hi when the person M1 is moving is different from the channel state information Hi when the person M1 is breathing. Therefore, the hmn when the person M1 is moving shown in FIG. 5 is different from the hmn when the person M1 is breathing shown in FIG. 6.

More precisely, the amplitude of hmn when person M1 moves as shown in Figure 5 is different from the amplitude of hmn when person M1 breathes as shown in Figure 6. In this embodiment, the amplitude of hmn when person M1 moves as shown in Figure 5 is greater than the amplitude of hmn when person M1 breathes as shown in Figure 6. Therefore, the determination device 14 can determine the presence or absence of movement of person M1 in the first area A1 by calculating the amplitude of hmn.

When the position of the object (person M1) in the first area A1 changes, the channel state information Hi changes. Therefore, when the position of person M1 changes, the channel state information Hi changes. Therefore, the determination device 14 can determine the position of person M1 in the first area A1 by calculating the amplitude of hmn and the phase of hmn.

From the above, the determination device 14 can perform a determination related to the position of an object in the first area A1 by calculating the amplitude of hmn, etc. The determination related to the position of an object is a determination of the position of person M1, the presence or absence of motion of person M1, and the position of objects other than person M1.

In addition, the determination device 14 can determine the presence or absence of a person M2 in the second area A2 by analyzing the amplitude of hmn, etc. In other words, in this embodiment, the determination device 14 can determine the presence or absence of a person M2 outside the vehicle. Hereinafter, a detailed description will be given with reference to the drawings. FIG. 7 is a graph showing the amplitude of hmn when a person M2 located in the second area A2 is breathing. FIG. 8 is a graph showing the amplitude of hmn when a person M2 is not present in the second area A2. The vertical axis of FIG. 7 and FIG. 8 is the amplitude. The horizontal axis of FIG. 7 and FIG. 8 is the time. FIG. 7 and FIG. 8 are experimental results when a person M1 is not present in the automobile. FIG. 9 is a graph showing the result of FFT (Fast Fourier Transform) processing of the waveform showing the amplitude of hmn in FIG. 7. FIG. 10 is a graph showing the result of FFT processing of the waveform showing the amplitude of hmn in FIG. 8. The horizontal axis of FIG. 9 and FIG. 10 is the frequency. The vertical axis in FIG. 9 and FIG. 10 is amplitude.

2 and 3, the state of the electromagnetic waves changes depending on the presence or absence of an object in the second area A2. Specifically, the electromagnetic waves received by the first receiving antenna 12-1 through the Rth receiving antenna 12-R when an object is present in the second area A2 are different from the electromagnetic waves received by the first receiving antenna 12-1 through the Rth receiving antenna 12-R when no object is present in the second area A2. This is explained in detail below.

As shown in FIG. 3, the electromagnetic wave W1 transmitted from the first transmitting antenna 10-1 to the Tth transmitting antenna 10-T reaches the window of the vehicle. Windows are easily permeable to electromagnetic waves. Therefore, the electromagnetic wave W1 travels through the window to the second area A2. Here, if an object is present in the second area A2, the electromagnetic wave W1 reaches the object present in the second area A2. In this case, the electromagnetic wave W1 is reflected by the object present in the second area A2. The reflected electromagnetic wave W1 reaches the first area A1. The electromagnetic wave W1 that reaches the first area A1 reaches the first receiving antenna 12-1 to the Rth receiving antenna 12-R, for example, by repeatedly reflecting within the first area A1. On the other hand, if there is no object present in the second area A2, the electromagnetic wave W1 is not reflected in the second area A2. Therefore, if there is no object present in the second area A2, the electromagnetic wave W1 does not reach the first receiving antenna 12-1 to the Rth receiving antenna 12-R.

As described above, the state of the electromagnetic wave W1 changes depending on the presence or absence of an object in the second area A2. In other words, when an object, such as a person M2, is present in the second area A2, the state of the electromagnetic wave W1 changes.

Here, the channel state information is information indicating the state of the transmission path of the electromagnetic wave between the first transmitting antenna 10-1 to the Tth transmitting antenna 10-T and the first receiving antenna 12-1 to the Rth receiving antenna 12-R. Therefore, the channel state information Hi changes depending on the presence or absence of the person M2 in the second area A2. That is, the channel state information Hi when the person M2 is present in the second area A2 is different from the channel state information Hi when the person M2 is not present in the second area A2. Therefore, the hmn when the person M2 is present in the second area A2 shown in FIG. 7 (hereinafter referred to as the hmn when the person is present) is different from the hmn when the person M2 is not present in the second area A2 shown in FIG. 8 (hereinafter referred to as the hmn when the person is absent). For example, the person M2 performs periodic movements such as breathing. Therefore, when the person M2 is present in the second area A2, the hmn when the person is present includes information indicating the periodic movements of the person. The hmn when a person is present includes, for example, a frequency component P1 indicative of breathing, which is a periodic human motion. In this case, as shown in Fig. 9, the hmn when a person is present includes a frequency component P1 of about 2 Hz indicative of breathing.

On the other hand, the hmn when no person is present, as shown in Figure 8, does not include information indicating periodic human motion. Specifically, as shown in Figure 10, it does not include the frequency component P1 indicating breathing, which is a periodic human motion. From the above, the determination device 14 can determine the presence or absence of a person M2 in the second area A2 by determining whether or not the hmn includes information indicating periodic human motion.

In the above description, the determination device 14 uses hmn of the channel state information Hi to determine the position of an object in the first area A1 and the presence or absence of a person M2 in the second area A2. However, the determination device 14 uses h11 to hRT of the channel state information H1 to HN to determine the position of an object in the first area A1 and the presence or absence of a person M2 in the second area A2. In this way, by using many components of the channel state information, the determination device 14 can accurately determine the position of an object in the first area A1 and the presence or absence of a person M2 in the second area A2.

In this embodiment, the determination device 14 determines the position of an object in the first region A1 using a machine learning model. Specifically, the machine learning model is used as training data indicating the relationship between the channel state information and the position of an object in the first region A1. Therefore, the machine learning model learns the relationship between the channel state information and the position of an object in the first region A1 in advance using the training data indicating the relationship between the channel information and the position of an object in the first region A1. Then, the determination device 14 determines the position of an object in the first region A1 corresponding to the channel state information calculated by the determination device 14 using the machine learning model. In this embodiment, the determination device 14 has a machine learning model.

Furthermore, in this embodiment, the determination device 14 uses a machine learning model to determine the presence or absence of a person M2 in the second area A2. The machine learning model uses the relationship between the channel state information and the movement of the person M2 located in the second area A2 as training data. For example, the machine learning model acquires channel state information when the person M2 is breathing in the second area A2 (hereinafter referred to as breathing channel state information). The machine learning model calculates a feature included in the breathing channel state information. The machine learning model learns the calculated feature as a feature indicating the person's breathing. In this case, the machine learning model determines whether the channel state information acquired in the acquisition step includes a feature indicating the person's breathing. If the machine learning model determines that the channel state information acquired in the acquisition step includes a feature indicating the person's breathing, it determines that the person M2 is present in the second area A2. In addition, the determination device 14 may use one machine learning model to determine the position of an object in the first area A1 and the presence or absence of a person M2 in the second area A2, or may use a first machine learning model to determine the position of an object in the first area A1 and a second machine learning model to determine the presence or absence of a person M2 in the second area A2.

Next, the operation of the determination device 14 will be described with reference to the drawings. FIG. 11 is a flowchart showing the operation executed by the determination device 14. A storage device (not shown) stores the determination program of the flowchart shown in FIG. 11. The determination device 14 then reads out this determination program from the storage device and executes it.

The determination device 14 calculates channel state information H1 to HN based on the first to Rth received signals of the first to Nth subcarriers received by the first receiving antenna 12-1 to the Rth receiving antenna 12-R (calculation step, step S1). Details of the calculation step have already been explained, so further explanation will be omitted. As a result, the determination device 14 acquires the calculated channel state information H1 to HN (acquisition step, step S2). Thus, in the acquisition step of step S2, the determination device 14 acquires the channel state information H1 to HN calculated based on the first to Rth received signals of the first to Nth subcarriers received by the first receiving antenna 12-1 to the Rth receiving antenna 12-R.

Next, the determination device 14 makes a determination related to the position of an object in the first area A1 and the presence or absence of a person M2 in the second area A2 based on the channel state information H1 to HN acquired in the acquisition step (determination step, step S3). In the determination step, the determination device 14 determines the presence or absence of a person M2 in the second area A2, for example, by detecting the breathing of the person M2 in the second area A2. The details of the determination step have already been explained, so further explanation will be omitted. Thereafter, the determination device 14 displays the determination result on a display device not shown.

(effect)
The determination device 14 provides a new sensing technique for sensing a specific first area A1, such as the interior of an automobile. More specifically, the determination device 14 acquires channel state information H1 to HN calculated based on the first to Rth reception signals of the first to Nth subcarriers received by the first reception antenna 12-1 to Rth reception antenna 12-R. The channel state information H1 to HN is information indicating the state of the transmission path of the electromagnetic wave between the first transmission antenna 10-1 to Tth transmission antenna 10-T and the first reception antenna 12-1 to Rth reception antenna 12-R in the first area A1. Therefore, the determination device 14 can make a determination related to the position of an object in the first area A1 based on the channel state information H1 to HN.

Furthermore, the channel state information H1-HN when person M2 is present in the second area A2 is different from the channel state information H1-HN when person M2 is not present in the second area A2. Therefore, based on the channel state information H1-HN, the determination device 14 can determine the presence or absence of person M2 in the second area A2 adjacent to the first area A1 while making a determination related to the position of an object in the cabin of the automobile (first area A1). In this way, the determination device 14 can obtain a new sensing technology for sensing a specific first area A1 such as the interior of an automobile.

(Modification)
The structure of a transmission/reception system 1a including a determination device 14a according to a modified example will be described below with reference to the drawings. Fig. 9 is a block diagram of the transmission/reception system 1a.

The transmission/reception system 1a differs from the transmission/reception system 1 in that it includes a determination device 14a and an arithmetic device 16 instead of the determination device 14. The determination device 14a is a processing circuit such as a CPU or a GPU. The arithmetic device 16 is a processing circuit such as a CPU or a GPU. In this way, the determination device 14a and the arithmetic device 16 are fabricated as separate semiconductor integrated circuits.

The calculation device 16 calculates channel state information H1 to HN based on the first to Rth reception signals of the first to Nth subcarriers received by the first receiving antenna 12-1 to the Rth receiving antenna 12-R. The determination device 14a acquires the channel state information H1 to HN calculated by the calculation device 16. As a result, the determination device 14a acquires the channel state information H1 to HN calculated based on the first to Rth reception signals of the first to Nth subcarriers received by the first receiving antenna 12-1 to the Rth receiving antenna 12-R (acquisition step). Furthermore, the determination device 14a makes a judgment related to the position of an object in the first area A1 and judges the presence or absence of a person M2 in the second area A2 based on the channel state information H1 to HN acquired in the acquisition step (determination step). The other structures of the transmission/reception system 1a are the same as those of the transmission/reception system 1, so the explanation will be omitted. The determination device 14a achieves the same effects as the determination device 14.

Other Embodiments
The determination device according to the present invention is not limited to the determination devices 14 and 14a, and can be modified within the scope of the invention.

In addition, in the determination step, the determination device 14, 14a may determine the presence or absence of a person M2 in the second area A2 using a program other than a machine learning model. The program other than a machine learning model may be, for example, a program related to template matching using template data.

In addition, the machine learning model may be a model that does not use training data.

The determination device 14, 14a can detect objects other than the person M2 present in the second area A2. Objects other than the person M2 do not perform any motion, such as breathing. Therefore, the determination device 14, 14a analyzes the hmn, for example, when the state of the electromagnetic wave W1 changes. If the determination device 14, 14a determines that the hmn does not contain information indicating periodic motions of a person, it determines that the object present in the second area A2 is not a person. As a result, the determination device 14, 14a can detect objects other than the person M2 present in the second area A2. In this case, objects other than the person M2 are, for example, inanimate objects such as utility poles and guardrails.

In addition, the determination device 14, 14a can detect living beings other than human M2 present in the second area.

The determination device 14, 14a may determine the presence or absence of a person M2 in the second area A2 by detecting a motion other than breathing. Examples of motion other than breathing include walking, running, etc.

In addition, in the determination step, the determination device 14, 14a performs a determination related to the position of an object in the first region. Therefore, the determination device 14, 14a may perform at least one of the following as a determination related to the position of an object: determining the position of a person, determining the presence or absence of a person's motion, and determining the position of an object other than a person.

In addition, if the vehicle is autonomous, the vehicle does not need windows. In this case, it is sufficient if part of the vehicle's cabin is made of a material that allows electromagnetic waves to pass through to the outside of the cabin.

The vehicle is equipped with a control device that performs driving control. In this case, the control device may perform driving control based on the result of determining whether or not a person M2 is present in the second area A2. For example, the control device may perform driving control so as to prevent contact between the vehicle and person M2 based on the result of determining whether or not a person M2 is present in the second area A2. Control to prevent contact between the vehicle and person M2 is, for example, brake control, steering control, etc. by the control device.

The first area A1 may be a space inside a building. In this case, the second area A2 is outside the building. Therefore, the determination device 14, 14a may determine the presence or absence of a person M2 outside the building.

The first area A1 and the second area A2 may be located within the same building. For example, the first area A1 is one of one or more rooms in the building (hereinafter referred to as the first room). In this case, the second area A2 is a room adjacent to the first room (hereinafter referred to as the second room). In this case, it is sufficient that a part of the first room and a part of the second room are made of a material that can transmit electromagnetic waves.

The first area A1 is, for example, a closed space. However, the first area A1 does not have to be a closed space. In this case, the first area A1 and the second area A2 may be connected. For example, when the first area A1 is a space inside a building and the second area A2 is outside the building, the first area A1 and the second area A2 may be connected via an open window or an open door, etc.

Similarly, when the first area A1 is a cabin of a vehicle and the second area A2 is outside the vehicle, the first area A1 and the second area A2 may be connected via an open window, an open door, etc.

The vehicle may be an open-top car without a roof. In this case, the first area A1 and the second area A2 are, for example, as follows. The direction parallel to the direction of gravity acting on the vehicle (open-top car) is defined as the up-down direction. In this case, the first area A1 is the area surrounded by the body of the open-top car when looking at the open-top car in the up-down direction. In this case, the second area A2 surrounds the periphery of the first area A1 when looking at the open-top car in the up-down direction. In this case, the first area A1 and the second area A2 are connected.

The vehicle may be a vehicle other than an automobile. Examples of the vehicle include a train, an airplane, a rocket, a helicopter, a ship, etc. In this case, the determination device 14, 14A can detect a suspicious person approaching the vehicle, for example, when the vehicle is stored in a garage, etc.

In addition, the determination device 14, 14a may output the determination result of the presence or absence of person M2 in the second area A2 as audio via a speaker, instead of displaying the determination result of the presence or absence of person M2 in the second area A2 on a display device.

In addition, the determination device 14, 14a may perform the determination step based on a portion of the channel state information H1 to HN. In addition, the determination device 14, 14a may perform the determination step based on a portion of the components of the channel state information H1 to HN.

In addition, the determination device 14, 14a may perform the determination step based on the processed channel state information H1 to HN. The processed channel state information H1 to HN is, for example, data from which high frequency components have been removed from the channel state information H1 to HN to make it easier to perform the determination step.

The determination device 14, 14a does not necessarily have to have a machine learning model. For example, a device such as a server different from the determination device 14, 14a may have the machine learning model. In this case, the determination device 14, 14a transmits channel state information to a device such as a server that has the machine learning model. The determination device 14, 14a receives a determination result of the position of an object in the first area A1 or a determination result of the presence or absence of a person M2 in the second area A2 from the device such as the server.

In addition, by increasing the intensity of the electromagnetic waves transmitted by the transmitting device 9, the electromagnetic waves W1 reflected in the second area A2 can easily reach the first area A1. Therefore, by increasing the intensity of the electromagnetic waves transmitted by the transmitting device 9, it becomes easier to detect the presence or absence of a person M2 in the second area A2.

Note that the state of the electromagnetic wave transmission path shown in Figures 3 and 4 is an example. Therefore, the state of the electromagnetic wave transmission path during actual use of the determination device 14, 14a does not necessarily have to match the state of the transmission path shown in Figures 3 and 4.

In addition, the judgment device 14, 14a does not necessarily need to use FFT to determine the presence or absence of a person M1 in the second area A2.

In addition, the determination device 14, 14a may determine the presence or absence of motion of person M1 in the first area A1 by calculating the phase of hmn. For example, the phase of hmn when person M1 is moving may differ from the phase of hmn when person M1 is breathing. In this case, the determination device 14, 14a can determine the presence or absence of motion of person M1 in the first area A1 by calculating the phase of hmn.

1, 1a: Transmission/reception system 9: Transmission devices 10-1 to 10-T: 1st transmission antenna to Tth transmission antenna 11: Reception devices 12-1 to 12-R: 1st reception antenna to Rth reception antenna 14, 14a: Determination device 16: Calculation device A1: 1st area A2: 2nd area M1, M2: Person

Claims (8)

A determination device used in a transmission/reception system in which first to N-th subcarrier signals transmitted by electromagnetic waves from a first to T-th transmission antennas are received by a first to R-th reception antennas, the determination device comprising:
N, T, and R are integers of 1 or more;
the first transmitting antenna through the T transmitting antenna and the first receiving antenna through the R receiving antenna are arranged in a first area,
The channel state information is information indicating a state of a transmission path of the electromagnetic wave between the first transmitting antenna to the T transmitting antenna and the first receiving antenna to the R receiving antenna,
The determination device includes:
an acquisition step of acquiring the channel state information calculated based on signals of the first subcarrier through the Nth subcarrier received by the first receiving antenna through the R receiving antenna;
a determination step of performing a determination related to a position of an object in the first region and a determination of the presence or absence of a person in a second region adjacent to the first region based on the channel state information acquired in the acquisition step;
Run
the first area is a cabin of a vehicle;
the second region is outside the vehicle;
The determination device determines whether or not there is a person outside the vehicle.
Judging device. The determination device includes:
A calculation step of calculating the channel state information based on signals of the first subcarrier to the Nth subcarrier received by the first receiving antenna to the R receiving antenna,
Run,
The determination device acquires the calculated channel state information in the acquisition step.
The determination device according to claim 1 . The signals transmitted from the first transmitting antenna through the T transmitting antenna are complex numbers x1 through xT, respectively;
The signals received by the first to R receiving antennas are represented by complex numbers y1 to yR, respectively;
x1 to xT and y1 to yR satisfy formulas (1) to (5),

i is an integer between 1 and N,
m is an integer of 1 to R,
n is an integer between 1 and T,
Hi is the channel state information of the i-th subcarrier,
||h|| is the amplitude of h,
∠hmn is the phase of hmn,
ni is the noise vector,
The determination device according to claim 1 or 2. In the determining step, the determination device determines the presence or absence of a person in the second area by using a machine learning model.
The determination device according to claim 1 or 2 . The machine learning model uses a relationship between the channel state information and the movement of a person located in the second area as training data.
The determination device according to claim 4. In the determining step, the determination device determines the presence or absence of a person in the second area by detecting breathing of the person in the second area.
The determination device according to claim 1 or 2 . When the position of the object in the first region changes, the channel state information changes.
The determination device according to claim 1 or 2 . A determination device used in a transmission/reception system in which first to N-th subcarrier signals transmitted by electromagnetic waves from a first to T-th transmission antennas are received by a first to R-th reception antennas, the determination device comprising:
N, T, and R are integers of 1 or more;
the first transmitting antenna through the T transmitting antenna and the first receiving antenna through the R receiving antenna are arranged in a first area,
The channel state information is information indicating a state of a transmission path of the electromagnetic wave between the first transmitting antenna to the T transmitting antenna and the first receiving antenna to the R receiving antenna,
The determination device includes:
an acquisition step of acquiring the channel state information calculated based on signals of the first subcarrier through the Nth subcarrier received by the first receiving antenna through the R receiving antenna;
a determination step of performing a determination related to a position of an object in the first region and a determination of the presence or absence of a person in a second region adjacent to the first region based on the channel state information acquired in the acquisition step;
Run
The first area is a space inside a building,
the second area is outside a building;
The determination device determines whether or not there is a person outside the building .
Judging device.

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