JP7617558B2 - Discrimination system, discrimination method, and program - Google Patents

Description

The present disclosure generally relates to a discrimination system, a discrimination method, and a program, and more specifically to a discrimination system, a discrimination method, and a program having multiple antennas.

Patent Document 1 describes a surrounding object identification system that identifies surrounding objects. The surrounding object identification system described in Patent Document 1 includes a radar device that measures the relative positions of objects around a vehicle, which is an automobile equipped with the surrounding object identification system. The surrounding object identification system described in Patent Document 1 calculates the occurrence frequency distribution of the relative positions of objects, and estimates the size of the left-right range in which the occurrence frequency is equal to or greater than a predetermined level based on the calculated occurrence frequency distribution as the width of the target object whose occurrence frequency distribution has been calculated.

JP 2008-003662 A

In the surrounding object identification system described in Patent Document 1, when multiple objects exist close to each other, it is not possible to distinguish that there are multiple objects. When multiple objects exist close to each other, it is not possible to distinguish that there are multiple objects, which reduces the accuracy of estimating the size of the object and the type of the object. In other words, there is a possibility that the accuracy of object detection will be reduced.

The present disclosure has been made in consideration of the above-mentioned reasons, and aims to provide a discrimination system, discrimination method, and program capable of discriminating between multiple objects.

In order to solve the above problem, a discrimination system according to an aspect of the present disclosure includes a radio wave sensor, a directivity control unit, an extraction unit, a calculation unit, and a discrimination unit. The radio wave sensor has a plurality of antennas that transmit radio waves and receive reflected waves of the radio waves. The directivity control unit switches the directivity of the plurality of antennas between a first direction and a second direction that is an angle offset based on the first direction. The extraction unit extracts biometric information based on the reflected waves received by the radio wave sensor from the first direction as first biometric information, and extracts biometric information based on the reflected waves received by the radio wave sensor from the second direction as second biometric information. The calculation unit calculates a degree of agreement between the first biometric information and the second biometric information extracted by the extraction unit. The discrimination unit compares the degree of agreement calculated by the calculation unit with a threshold value to determine whether an object located in the first direction is the same as an object located in the second direction. The biometric information includes at least one of information on heartbeat and information on respiration.

A discrimination method according to an aspect of the present disclosure includes a directivity control step, an extraction step, a calculation step, and a discrimination step. In the directivity control step, the directivities of a plurality of antennas that transmit radio waves and receive reflected waves of the radio waves are switched between a first direction and a second direction that is an angle offset based on the first direction. In the extraction step, biometric information based on the reflected waves received by the plurality of antennas from the first direction is extracted as first biometric information, and biometric information based on the reflected waves received by the plurality of antennas from the second direction is extracted as second biometric information. In the calculation step, a degree of agreement between the first biometric information extracted in the extraction step and the second biometric information is calculated. In the discrimination step, the degree of agreement calculated in the calculation step is compared with a threshold value to determine whether an object located in the first direction is the same as an object located in the second direction . The biometric information includes at least one of information on heartbeat and information on respiration.

A program according to one aspect of the present disclosure is a program for causing one or more processors to execute the discrimination method.

The present disclosure provides a discrimination system, discrimination method, and program that can discriminate between multiple objects.

FIG. 1 is a schematic diagram showing the overall configuration of a discrimination system according to a first embodiment. 2A and 2B are schematic diagrams showing angles of transmission and reception of radio waves in the discrimination system according to the above embodiment. 3A to 3C are schematic diagrams showing the directivity of the antenna according to the above embodiment. 4A to 4C are schematic diagrams showing the directivity of the antenna according to the above embodiment. 5A and 5B are schematic diagrams showing an example of a biological signal acquired by the discrimination system according to the above embodiment. FIG. 6 is a schematic diagram showing the correlation of the biological signals according to the above embodiment. FIG. 7 is a flowchart showing the operation of the discrimination system according to the above embodiment. 8A and 8B are schematic diagrams showing vital sign estimated values according to a modified example. FIG. 9 is a schematic diagram showing the degree of agreement of biological signals according to the second embodiment. FIG. 10 is a flowchart showing the operation of the discrimination system according to the above embodiment. FIG. 11 is a flowchart showing the operation of the discrimination system according to the above embodiment.

A preferred embodiment of the present disclosure will be described in detail below with reference to the drawings. In the embodiments described below, common elements are given the same reference numerals, and duplicated descriptions of the common elements will be omitted. The following embodiment is merely one of various embodiments of the present disclosure. Various modifications of the embodiment are possible depending on the design, etc., as long as the object of the present disclosure can be achieved. Each figure described in this disclosure is a schematic diagram, and the respective ratios of the size and thickness of each component in each figure do not necessarily reflect the actual dimensional ratio. Note that the arrows indicating each direction are merely examples, and are not intended to specify the directions when the discrimination system 1 is used. Also, the arrows indicating each direction in the drawings are merely indicated for explanatory purposes, and do not have any substance.

(Embodiment 1)
(1) Overview First, an overview of a discrimination system 1 according to this embodiment will be described with reference to FIGS. 1, 2A, and 2B.

As shown in FIG. 1, the discrimination system 1 according to this embodiment is provided in a vehicle 100. For example, the discrimination system 1 according to this embodiment estimates whether a person (target) sitting in a seat 102 (see FIG. 2A) of the vehicle 100 is an adult or a child. In this disclosure, the "target" is an object for which the discrimination system 1 estimates the size and type of the object. The "target" includes, for example, people and animals such as pets. When the target is a person, the "type" includes elements such as child, adult, and elderly, and the "child" further includes elements such as newborn, infant, toddler, and schoolchild. When the target is a pet, the "type" includes elements such as dog, cat, and bird. When the target is a wild animal, the "type" includes elements such as monkey, boar, deer, and bear.

The discrimination system 1 includes a radio wave sensor 2 having multiple antennas 21. As shown in FIG. 2A and FIG. 2B, the radio wave sensor 2 transmits radio waves having directivity in a first direction D1 and radio waves having directivity in a second direction D2 in a discrimination area 101 inside the vehicle 100. The radio wave sensor 2 receives reflected waves from the first direction D1 and the second direction D2.

The discrimination system 1 of this embodiment extracts biometric information based on the reflected wave from the reflected wave. More specifically, the discrimination system 1 extracts first biometric information based on the reflected wave from the reflected wave received from the first direction D1, and extracts second biometric information based on the reflected wave from the reflected wave received from the second direction D2.

The discrimination system 1 of this embodiment calculates the degree of agreement between the first biometric information and the second biometric information, and determines whether an object (target) located in the first direction D1 and an object located in the second direction D2 are the same based on the calculated degree of agreement. In the following description, the discrimination system 1's discrimination of whether a target located in the first direction D1 and an object located in the second direction D2 are the same is sometimes referred to as "identity discrimination". As shown in FIG. 2A, when the same target T1 (adult) is located in the first direction D1 and the second direction D2, the degree of agreement between the first biometric information and the second biometric information is relatively high. Therefore, the discrimination system 1 of this embodiment determines that an object (target T1) located in the first direction D1 and an object (target T1) located in the second direction D2 are the same. On the other hand, as shown in FIG. 2B, when a target T2 (child) is located in the first direction D1 and the target T2 is not located in the second direction D2, the degree of agreement between the first biometric information and the second biometric information is relatively low. Therefore, the discrimination system 1 of this embodiment determines that the object (target T2) located in the first direction D1 and the object (seat 102, body, etc.) located in the second direction D2 are not the same.

The discrimination system 1 of this embodiment can determine whether an object located in the first direction D1 and an object located in the second direction D2 are the same, and can determine that there are multiple objects when multiple objects are close to each other. This allows the discrimination system 1 to improve the accuracy of type estimation, such as whether a target sitting in the seat 102 is an adult or a child.

(2) Details Hereinafter, the discrimination system 1 according to this embodiment will be described in detail with reference to FIGS.

(2.1) Configuration of the Discrimination System As shown in Fig. 1, the discrimination system 1 of this embodiment is provided in a vehicle 100. The vehicle 100 is, for example, a passenger car equipped with a vehicle body capable of accommodating a plurality of occupants.

The discrimination system 1 includes a radio wave sensor 2, a transceiver 3, a direction estimation unit 4, an extraction unit 5, a calculation unit 6, a discrimination unit 7, a size estimation unit 8, a type estimation unit 9, and a memory unit 10.

The radio wave sensor 2 has a plurality of antennas 21. Specifically, the radio wave sensor 2 of this embodiment has a plurality of antennas 21 arranged in a first arrangement direction Ar1 and a plurality of antennas 21 arranged in a second arrangement direction Ar2 intersecting the first arrangement direction Ar1. The first arrangement direction Ar1 of this embodiment is a direction along a horizontal plane. The second arrangement direction Ar2 is along a vertical direction. That is, the first arrangement direction Ar1 and the second arrangement direction Ar2 of this embodiment are perpendicular to each other. The plurality of antennas 21 are capable of transmitting and receiving radio waves, and receive reflected waves of the transmitted radio waves. As shown in FIG. 2A and FIG. 2B, the radio wave sensor 2 of this embodiment is disposed at the rear end of the center console 103 inside the vehicle 100.

The transceiver 3 shown in FIG. 1 transmits radio waves (transmission waves) from multiple antennas 21 and controls the frequency, transmission timing, etc. of the transmission waves. As shown in FIG. 2A and FIG. 2B, the transmission waves are radiated to a discrimination area 101. As shown in FIG. 2A and FIG. 2B, in this embodiment, the front-rear and left-right directions are defined based on a person looking forward (the direction of the vehicle 100). In this embodiment, the direction perpendicular to the front-rear and left-right directions is defined as the up-down direction. In this embodiment, the first array direction Ar1 is a direction along the left-right direction, and the second array direction Ar2 is a direction along the up-down direction. In the following description, the length in the left-right direction may be referred to as "width".

The transmission waves transmitted from the multiple antennas 21 are, for example, microwaves. The transmission waves transmitted from the multiple antennas 21 are reflected by objects such as living bodies and metals within the discrimination area 101. That is, the multiple antennas 21 receive reflected waves reflected by objects such as targets T1 and T2 within the discrimination area 101 and metals such as the body of the vehicle 100 and the framework of the seats 102.

As shown in FIG. 1, the transceiver 3 is equipped with a directivity control unit 31.

The directivity control unit 31 switches the directivity of the multiple antennas 21 (radio wave sensor 2) between a first direction D1 and a second direction D2 that is an angle offset from the first direction D1 as shown in Figures 2A and 2B. The first direction D1 in this embodiment is the arrival direction of the reflected wave estimated by the direction estimation unit 4 (see Figure 1), which will be described later. In other words, an object (target) that reflects radio waves exists in the first direction D1. The first direction D1 in this embodiment is set to a direction that is +20° from the reference direction D0 of the radio wave sensor 2. The offset amount in the negative direction (counterclockwise direction in Figure 2A) is set to an angle dθ1.

The angle dθ1, which is the offset amount of the directivity control unit 31 of this embodiment, is set in advance according to the distance r1 between the radio wave sensor 2 and the target existing in the first direction D1. The discrimination system 1 of this embodiment is provided in the vehicle 100 to estimate the type of the target sitting in the seat 102 of the vehicle 100, and the distance r1 between the radio wave sensor 2 and the target sitting in the seat 102 is generally constant. Since the distance r1 is generally constant, it is possible to set in advance a boundary angle for estimating the type of the target. The "boundary angle" is, for example, an angle that is a boundary between an adult and a child. An adult is likely to be present in the second direction D2 offset by the boundary angle from the first direction D1, but a child is likely to be absent in the second direction D2 offset by the boundary angle from the first direction D1, which is the boundary angle. In this embodiment, the angle dθ1, which is the offset amount, is set in advance to, for example, 10°. That is, the directivity control unit 31 of this embodiment switches the directivity of the multiple antennas 21 between a first direction D1 and a second direction D2 that is offset by an angle of 10° from the first direction D1.

In the directivity control unit 31 of this embodiment, radio waves having directivity in the first direction D1 and the second direction D2 (transmit beamforming) may be transmitted and reflected waves from the first direction D1 and the second direction D2 may be received, or radio waves with low directivity may be transmitted and the radio waves (signals) received by the multiple antennas 21 may be weighted to selectively receive reflected waves from the first direction D1 and the second direction D2 (receive beamforming).

The directivity control unit 31 of this embodiment controls the directivity of the multiple antennas 21, for example, by transmit beamforming. For example, when the first direction D1 is a direction at +20° from the reference direction D0 (see FIG. 2A) of the radio wave sensor 2, the directivity of the multiple antennas 21 becomes as shown in FIG. 3A under the control of the directivity control unit 31. Also, as described above, the directivity control unit 31 switches the directivity of the multiple antennas 21 from the first direction D1 to the second direction D2. For example, when the second direction D2 is a direction offset by -10° with respect to the first direction D1, the directivity of the multiple antennas 21 becomes as shown in FIG. 3B under the control of the directivity control unit 31. Also, when the second direction D2 is a direction offset by +10° with respect to the first direction D1, the directivity of the multiple antennas 21 becomes as shown in FIG. 3C under the control of the directivity control unit 31.

The directivity control unit 31 may also control the directivity of the multiple antennas 21 by receive beamforming, for example using the Capon method. When the first direction D1 is a direction at +20° from the reference direction D0, the directivity of the multiple antennas 21 is controlled as shown in FIG. 4A by the directivity control unit 31. Also, for example, when the second direction D2 is a direction offset by -10° from the first direction D1, the directivity of the multiple antennas 21 is controlled as shown in FIG. 4B by the directivity control unit 31. Also, for example, when the second direction D2 is a direction offset by +10° from the first direction D1, the directivity of the multiple antennas 21 is controlled as shown in FIG. 4C by the directivity control unit 31.

The directivity control unit 31 of this embodiment controls the directivity of the multiple antennas 21 so that the width of the main lobe (main beam) is smaller than the width of the smallest type of the target. The "main lobe width" in this disclosure refers to a width in which the gain difference from the maximum gain value of the main lobe is equal to or less than a predetermined value. For example, the main lobe width is a width in which the gain difference from the maximum gain value of the main lobe is within 10 dB. Furthermore, the "smallest type" in this disclosure refers to a type with the smallest width among the multiple types when there are multiple types of targets of the discrimination system 1. For example, when the target of the discrimination system 1 is a person and there are two types of people, "adult" and "child", the smallest type is a child. The discrimination system 1 can improve the discrimination accuracy of identity discrimination, the accuracy of size estimation, the accuracy of type estimation, etc. by controlling the directivity so that the width of the main lobe is smaller than the width of the smallest type.

The direction estimation unit 4 estimates the direction of arrival of the reflected waves based on the phase difference of the reflected waves received by the multiple antennas 21. The direction estimation unit 4 outputs information about the estimated direction of arrival to the directivity control unit 31.

The extraction unit 5 extracts biometric information based on the reflected wave received from the first direction D1 as first biometric information, and extracts biometric information based on the reflected wave received from the second direction D2 as second biometric information.

The extraction unit 5 performs signal processing on the reflected waves received by the radio wave sensor 2 to generate measurement data (body movement measurement data) indicative of the body movement of the target present in the discrimination area 101. The extraction unit 5 also filters the measurement data indicative of the body movement of the target and extracts the frequency components of the body movement caused by the heartbeat to generate a heartbeat waveform (heartbeat measurement data) indicative of the body movement caused by the heartbeat. The extraction unit 5 also filters the measurement data indicative of the body movement of the target and extracts the frequency components of the body movement caused by breathing to generate a breathing waveform (respiration measurement data) indicative of the body movement caused by breathing. Here, the heartbeat waveform and breathing waveform are primary information obtained (extracted) from the reflected waves.

The extraction unit 5 of this embodiment also calculates the heart rate, which is an estimated vital value of the heart rate, based on the heart rate waveform. The extraction unit 5 also calculates the respiratory rate, which is an estimated vital value of the respiratory rate, based on the respiratory waveform. The heart rate and respiratory rate are secondary information obtained (calculated) from the primary information.

The first biological information may include at least one of primary information extracted from the reflected wave received from the first direction D1 and secondary information obtained from the primary information. The primary information may include at least one of a heartbeat waveform and a respiratory waveform. The first biological information of this embodiment includes a respiratory waveform BS1 (see FIG. 5A) which is primary information and a respiratory rate which is secondary information. FIG. 5A is a schematic diagram showing an example of a respiratory waveform BS1 included in the first biological information. The second biological information may include at least one of primary information extracted from the reflected wave received from the second direction D2 and secondary information obtained from the primary information. The primary information may include at least one of a heartbeat waveform and a respiratory waveform. The second biological information of this embodiment includes a respiratory waveform BS2 (see FIG. 5B) which is primary information and a respiratory rate which is secondary information. FIG. 5B is a schematic diagram showing an example of a respiratory waveform BS2 included in the second biological information.

The calculation unit 6 shown in FIG. 1 calculates the degree of agreement between the first biometric information and the second biometric information extracted by the extraction unit 5. For example, the calculation unit 6 calculates the degree of agreement based on the correlation (cross-correlation) between the primary information included in the first biometric information and the secondary information included in the second biometric information. The calculation unit 6 of this embodiment calculates the degree of agreement based on the cross-correlation between the respiratory waveform BS1 (see FIG. 5A) included in the first biometric information and the respiratory waveform BS2 (see FIG. 5B) included in the second biometric information.

Figure 6 is a diagram showing the correlation between respiratory waveforms BS1 and BS2. In this embodiment, the calculation unit 6 determines the correlation between respiratory waveforms BS1 and BS2, and then determines the maximum correlation value P1 as the degree of agreement between respiratory waveforms BS1 and BS2. The calculation unit 6 outputs information related to the calculated degree of agreement to the discrimination unit 7.

The discrimination unit 7 shown in FIG. 1 discriminates whether an object (target) located in the first direction D1 (see FIG. 2A) and an object located in the second direction D2 (see FIG. 2A) are the same based on the degree of coincidence calculated by the calculation unit 6. The discrimination unit 7 of this embodiment compares the degree of coincidence with a threshold value Th1 to determine whether a target located in the first direction D1 and an object located in the second direction D2 are the same. More specifically, when the degree of coincidence is equal to or greater than the threshold value Th1 (see FIG. 6), the discrimination unit 7 determines that the target located in the first direction D1 and the object located in the second direction D2 are the same. For example, when the degree of coincidence between the respiratory waveform BS1 and the respiratory waveform BS2 is the maximum value P1 in FIG. 6, the degree of coincidence is equal to or greater than the threshold value Th1, so that the discrimination unit 7 determines that the target located in the first direction D1 and the object located in the second direction D2 are the same. On the other hand, if the degree of match is less than the threshold value Th1, the discrimination unit 7 determines that the target located in the first direction D1 and the object located in the second direction D2 are not the same. In this embodiment, the discrimination unit 7 outputs the discrimination result to the size estimation unit 8.

The size estimation unit 8 shown in FIG. 1 estimates the size of a target located in the first direction D1 (see FIG. 2A) based on the result of the identity determination by the discrimination unit 7. More specifically, the size estimation unit 8 estimates the size of the target based on the distance r1 (see FIG. 2A) between the radio wave sensor 2 and the target located in the first direction D1 and the angle dθ1 (see FIG. 2A), which is the offset amount, in addition to the result of the determination by the discrimination unit 7. For example, assume that the distance r1 is 1 meter and the angle dθ1 is 10°. Then, when the discrimination unit 7 determines that the target located in the first direction D1 and the object located in the second direction D2 (see FIG. 2A) are the same, the size estimation unit 8 estimates the size (width) of the target in the horizontal direction to be, for example, 35 centimeters or more. On the other hand, when the discrimination unit 7 determines that the target located in the first direction D1 and the object located in the second direction D2 are not the same, the size estimation unit 8 estimates the width of the target in the horizontal direction to be, for example, less than 35 centimeters.

The type estimation unit 9 estimates the type of the target located in the first direction D1 based on the result of the identity determination by the discrimination unit 7. In the example of FIG. 2A, the discrimination unit 7 (see FIG. 1) determines that the target T1 located in the first direction D1 and the object (target T1) located in the second direction D2 are the same. The type estimation unit 9 of this embodiment then estimates that the target T1 located in the first direction D1 is an adult. In the example of FIG. 2B, the discrimination unit 7 determines that the target T2 located in the first direction D1 and the object located in the second direction D2 are not the same. The type estimation unit 9 of this embodiment then estimates that the target T2 located in the first direction D1 is a child.

The storage unit 10 is configured with a device selected from a ROM (Read Only Memory), a RAM (Random Access Memory), an EEPROM (Electrically Erasable Programmable Read Only Memory), etc. The storage unit 10 stores, for example, information on the angle θ1 of the first direction D1 that is preset, information on the distance r1 between the radio wave sensor 2 and the target that is preset, and information on the angle dθ1 that is the offset amount that is preset.

(2.2) Operation of the Discrimination System Next, the operation of the discrimination system 1 will be described with reference to Fig. 7. Fig. 7 is a flowchart showing the operation (discrimination process) of the discrimination system 1.

First, the discrimination system 1 transmits radio waves from the multiple antennas 21 to the discrimination area 101 (S1). The radio waves transmitted by the discrimination system 1 in the process of step S1 are, for example, non-directional (low directivity) radio waves. Next, the discrimination system 1 receives the reflected waves reflected by an object present in the discrimination area 101 with the multiple antennas 21 (S2). Next, the discrimination system 1 estimates the arrival direction of the reflected waves based on the phase difference of the reflected waves received by the multiple antennas 21 (S3). Next, the discrimination system 1 switches the directivity of the multiple antennas 21 to the first direction D1, which is the estimated arrival direction of the reflected waves, and transmits radio waves (S4). Next, the discrimination system 1 receives the reflected waves from the first direction D1 with the multiple antennas 21 (S5). Next, the discrimination system 1 extracts the first biometric information from the reflected waves from the first direction D1 (S6).

Next, the discrimination system 1 performs offset processing (S7), and switches the directivity of the multiple antennas 21 to the second direction D2, which is offset from the first direction D1 by, for example, 10 degrees to the negative side, and transmits radio waves (S8). Next, the discrimination system 1 receives reflected waves from the second direction D2 with the multiple antennas 21 (S9). Next, the discrimination system 1 extracts second biometric information from the reflected waves from the second direction D2 (S10). Next, the discrimination system 1 calculates the degree of agreement between the first biometric information and the second biometric information (S11). Next, the discrimination system 1 determines whether the object located in the first direction D1 and the object located in the second direction D2 are the same based on the calculated degree of agreement (S12). If the degree of agreement is equal to or greater than the threshold value Th1, that is, if the object located in the first direction D1 and the object located in the second direction D2 are the same (S12: Yes), the discrimination system 1 estimates that the target located in the first direction D1 is an adult (S13). Then, the discrimination system 1 ends the discrimination process. On the other hand, if the degree of match is less than the threshold value Th1, i.e., if the object located in the first direction D1 and the object located in the second direction D2 are not the same (S12: No), the discrimination system 1 estimates that the target located in the first direction D1 is a child (14). Then, the discrimination system 1 ends the discrimination process.

(3) Effects As described above, the discrimination system 1 of the present embodiment includes the radio wave sensor 2 having a plurality of antennas 21, the directivity control unit 31, the extraction unit 5, the calculation unit 6, and the discrimination unit 7. The extraction unit 5 extracts the first biometric information from the reflected wave received from the first direction D1, and extracts the second biometric information from the reflected wave received from the second direction D2. The calculation unit 6 calculates the degree of agreement between the first biometric information and the second biometric information. The discrimination unit 7 compares the degree of agreement calculated by the calculation unit 6 with a threshold value Th1 to determine whether a target located in the first direction D1 and an object located in the second direction D2 are the same or not. Since the discrimination system 1 can determine that an object located in the first direction D1 and an object located in the second direction D2 are different objects, for example, when multiple objects exist close to each other, it can determine that they are multiple objects. As a result, the discrimination system 1 can improve the accuracy of, for example, target size estimation and target classification (type) estimation.

The discrimination system 1 of this embodiment further includes a size estimation unit 8. The size estimation unit 8 estimates the size of the target located in the first direction D1 based on the discrimination result by the discrimination unit 7. The discrimination system 1 of this embodiment estimates the size of the target after determining whether the target located in the first direction D1 and the object located in the second direction D2 are the same or not, and therefore the accuracy of estimating the size of the target can be improved.

The biometric information (first biometric information or second biometric information) extracted by the extraction unit 5 from the reflected wave includes at least one of primary information and secondary information obtained from the primary information. The primary information includes at least one of a respiratory waveform and a heart rate waveform. The secondary information includes at least one of a respiratory rate obtained from the respiratory waveform and a heart rate obtained from the heart rate waveform. The discrimination system 1 can improve the accuracy of identity discrimination by performing identity discrimination using biometric information that is information that differs depending on the type of target, such as an adult and a child.

The discrimination system 1 of this embodiment further includes a direction estimation unit 4. The direction estimation unit 4 estimates the arrival direction of the reflected wave based on the phase difference of the reflected wave received by the multiple antennas 21. The first direction D1 is the arrival direction of the reflected wave estimated by the direction estimation unit 4. By including the direction estimation unit 4, the discrimination system 1 can determine the direction in which the target (object) is located as the first direction D1 even if, for example, the first direction D1 is not set in advance.

In addition, the angle dθ1, which is the offset amount of the directivity control unit 31 in this embodiment, is set in advance according to the distance r1 between the radio wave sensor 2 and the target. By setting the angle dθ1, which is the offset amount, in advance, the processing load on the discrimination system 1 can be reduced.

The calculation unit 6 of this embodiment also calculates the degree of agreement based on the cross-correlation between the first biometric information and the second biometric information. When calculating the degree of agreement using, for example, a heart rate waveform or a respiratory waveform, the calculation unit 6 calculates the degree of agreement based on the cross-correlation, thereby improving the accuracy of calculating the degree of agreement.

The radio wave sensor 2 of this embodiment also has multiple antennas 21, including multiple antennas 21 arranged in a first array direction Ar1 and multiple antennas 21 arranged in a second array direction Ar2 that intersects with the first array direction Ar1. More specifically, the first array direction Ar1 of this embodiment is a direction along a horizontal plane, and the second array direction Ar2 is a direction along the vertical direction. The discrimination system 1 can set the angle dθ1, which is the offset amount, in the azimuth angle direction and the elevation/depression angle direction.

(4) Modifications The above embodiment is merely one of various embodiments of the present disclosure. The above embodiment can be modified in various ways depending on the design and the like as long as the object of the present disclosure can be achieved.

In addition, the function equivalent to the discrimination system 1 according to the above embodiment may be embodied in a discrimination method, a (computer) program, or a non-transitory recording medium on which a program is recorded. The discrimination method according to one embodiment includes a directivity control step, an extraction step, a calculation step, and a discrimination step. In the directivity control step, the directivity of the multiple antennas 21 that receive the reflected waves of the radio waves is switched between a first direction D1 and a second direction D2 in which the angle is offset based on the first direction D1. In the extraction step, the multiple antennas 21 extract biometric information based on the reflected waves received from the first direction D1 as the first biometric information, and the multiple antennas 21 extract biometric information based on the reflected waves received from the second direction D2 as the second biometric information. In the calculation step, the degree of agreement between the first biometric information extracted in the extraction step and the second biometric information is calculated. In the discrimination step, the degree of agreement calculated in the calculation step is compared with a threshold value to determine whether an object located in the first direction D1 and an object located in the second direction D2 are the same or not. The program according to one embodiment is a program for causing one or more processors to execute the above-mentioned determination method.

The discrimination system 1 in the present disclosure includes, for example, a computer system. The computer system is mainly composed of a processor and a memory as hardware. The processor executes a program recorded in the memory of the computer system to realize the function of the discrimination system 1 in the present disclosure. The program may be pre-recorded in the memory of the computer system, provided through an electric communication line, or recorded and provided in a non-transitory recording medium such as a memory card, an optical disk, or a hard disk drive that can be read by the computer system. The processor of the computer system is composed of one or more electronic circuits including a semiconductor integrated circuit (IC) or a large-scale integrated circuit (LSI). The integrated circuits such as IC or LSI referred to here are called differently depending on the degree of integration, and include integrated circuits called system LSI, VLSI (Very Large Scale Integration), or ULSI (Ultra Large Scale Integration). Furthermore, a field-programmable gate array (FPGA) that is programmed after the manufacture of the LSI, or a logic device that can reconfigure the connection relationship inside the LSI or reconfigure the circuit partition inside the LSI, can also be adopted as a processor. The multiple electronic circuits may be integrated into one chip, or may be distributed across multiple chips. The multiple chips may be integrated into one device, or may be distributed across multiple devices. The computer system referred to here includes a microcontroller having one or more processors and one or more memories. Therefore, the microcontroller is also composed of one or more electronic circuits including a semiconductor integrated circuit or a large-scale integrated circuit.

Below, we will list some variations of the above embodiment. The variations described below can be applied in appropriate combinations.

It is not essential for the discrimination system 1 that at least some of the functions of the discrimination system 1 are concentrated in one device (vehicle 100), and the components of the discrimination system 1 may be distributed across multiple devices (housings).

For example, some of the functions of the discrimination system 1 may be provided in a device (housing) separate from the vehicle 100, such as a server. At least some of the functions of the discrimination system 1 may be realized, for example, by the cloud (cloud computing).

The discrimination system 1 may include at least a radio wave sensor 2, a directivity control unit 31, an extraction unit 5, a calculation unit 6, and a discrimination unit 7. The functions of the radio wave sensor 2, the directivity control unit 31, the extraction unit 5, the calculation unit 6, and the discrimination unit 7 may be separate.

In the above embodiment, the discrimination system 1 is provided in the vehicle 100, but the discrimination system 1 may be provided in a moving object other than the vehicle 100, such as an aircraft or a ship. The discrimination system 1 may also be provided in amusement equipment such as a roller coaster. The discrimination system 1 may also be provided in a facility. In the present disclosure, the term "facility" includes residential facilities used for residential purposes, as well as non-residential facilities such as stores (tenants), offices, welfare facilities, educational facilities, hospitals, and factories. Non-residential facilities also include restaurants, amusement parks, hotels, inns, kindergartens, nurseries, and community centers. In other words, the facility may be a residential facility such as an apartment building, or a non-residential facility such as an office building. Furthermore, the facility may include a facility in which residential facilities and non-residential facilities are mixed, such as a facility with stores on the lower floors and residences on the upper floors.

The discrimination system 1 may measure the distance r1 between the radio wave sensor 2 and an object (target) that reflects radio waves. For example, the transceiver 3 uses, for example, an FMCW (Frequency-Modulated Continuous-Wave) method. The transceiver 3 transmits a transmission wave whose frequency (transmission frequency) changes over time from multiple antennas 21, and receives a reflected wave whose frequency (reception frequency) changes over time via the multiple antennas 21. The transceiver 3 then generates a beat signal with a frequency (beat frequency) equal to the frequency difference between the transmission frequency and the reception frequency. The discrimination system 1 then determines the distance to the target based on the beat frequency. Since the discrimination system 1 can determine the distance r1 between the radio wave sensor 2 and the target, the discrimination system 1 (storage unit 10) does not need to store information in which the distance r1 between the radio wave sensor 2 and the target is preset.

The calculation unit 6 may simply compare the first bioinformation and the second bioinformation to calculate the degree of agreement. For example, the calculation unit 6 calculates the absolute value of the difference between the respiration rate BS3 (see FIG. 8A) as the first bioinformation and the respiration rate BS4 (see FIG. 8B) as the second bioinformation as the degree of agreement every predetermined time (for example, every second). Then, the discrimination unit 7 determines that the target located in the first direction D1 and the object located in the second direction D2 are the same when the degree of agreement is continuously less than the threshold value during a predetermined time (for example, 10 seconds). If the threshold value is, for example, 5, when the respiration rate BS3 and the respiration rate BS4 are the values shown in FIG. 8A, the discrimination unit 7 determines that the target located in the first direction D1 and the object located in the second direction D2 are the same. On the other hand, when the respiration rate BS3 and the respiration rate BS4 are the values shown in FIG. 8B, the discrimination unit 7 determines that the target located in the first direction D1 and the object located in the second direction D2 are not the same.

The calculation unit 6 may also calculate the degree of agreement between the first biometric information and the second biometric information by a t-test.

The discrimination unit 7 may also perform multiple identity discriminations and then determine whether or not the target located in the first direction D1 and the object located in the second direction D2 are the same. For example, the discrimination unit 7 performs identity discrimination based on the degree of agreement between the respiratory waveform BS1 and the respiratory waveform BS2, and identity discrimination based on the degree of agreement between the respiratory rate BS3 and the respiratory rate BS4. Then, based on the results of the two identity discriminations, the discrimination unit 7 determines whether or not the target located in the first direction D1 and the object located in the second direction D2 are the same. Note that, when multiple judgment results in multiple identity discriminations are different from each other, the discrimination unit 7 may prioritize one of the multiple identity judgments. For example, there are cases where the judgment result of the identity discrimination based on the degree of agreement between the respiratory waveform BS1 and the respiratory waveform BS2 and the judgment result of the identity discrimination based on the degree of agreement between the respiratory rate BS3 and the respiratory rate BS4 are different. In such a case, the discrimination unit 7 prioritizes the judgment result of the identity discrimination based on the degree of agreement between the respiratory waveform BS1 and the respiratory waveform BS2.

The discrimination unit 7 may also compare the degree of coincidence with multiple thresholds. The multiple degrees of coincidence include, for example, a first threshold (threshold Th1) and a second threshold smaller than the first threshold. For example, the discrimination unit 7 determines that the target located in the first direction D1 and the object located in the second direction D2 are the same when the degree of coincidence is equal to or greater than the first threshold, and determines that the target located in the first direction D1 and the object located in the second direction D2 are not the same when the degree of coincidence is less than the second threshold.

The size estimation unit 8 may also estimate the size of the target located in the first direction D1 by comparing the vital reference information (see Table 1) with the biometric information (estimated vital value). As shown in Table 1, the vital reference information is associated with vital reference values of "respiratory rate" and "heart rate" for each "size" and "type" of the target. If the discrimination unit 7 determines that the target located in the first direction D1 and the object located in the second direction D2 are the same, the size estimation unit 8 estimates the size of the target based on the estimated vital value included in at least one of the first biometric information and the second biometric information. If the discrimination unit 7 determines that the target located in the first direction D1 and the object located in the second direction D2 are not the same, the size estimation unit 8 estimates the size of the target based on the estimated vital value included in the first biometric information. The size estimation unit 8 can improve the accuracy of the size estimation by comparing the vital reference information with the biometric information extracted by the extraction unit 5. Note that the vital reference information is stored in advance in, for example, the storage unit 10.

The type estimation unit 9 may also estimate the type of a target located in the first direction D1 by comparing the vital reference information with the biometric information (estimated vital values).

The discrimination system 1 of the above embodiment transmits radio waves having directivity in the first direction D1 and the second direction D2 (transmit beamforming) and receives reflected waves from the first direction D1 and the second direction D2. The discrimination system 1 (directivity control unit 31) may selectively receive reflected waves from the first direction D1 and the second direction D2 (receive beamforming) by weighting the radio waves (signals) received by the multiple antennas 21. For example, the discrimination system 1 may transmit radio waves with low directivity in the process of step S4 of FIG. 4, and selectively receive reflected waves from the first direction D1 in the process of step S5. Also, for example, the discrimination system 1 may transmit radio waves with low directivity in the process of step S8, and selectively receive reflected waves from the second direction D2 in the process of step S9. The discrimination system 1 may perform both transmit beamforming and receive beamforming. For example, the discrimination system 1 may transmit radio waves in the first direction D1 in the process of step S4, and selectively receive reflected waves from the first direction D1 in the process of step S5.

(Embodiment 2)
(1) Overview The discrimination system 1 of this embodiment differs from the discrimination system 1 of embodiment 1 in that the directivity control unit 31 of this embodiment gradually increases the angle dθ1, which is the offset amount, until the degree of coincidence becomes less than the threshold value Th1. The discrimination system 1 of this embodiment also differs from the discrimination system 1 of embodiment 1 in that the directivity control unit 31 of this embodiment performs offsetting in the opposite direction as well. Hereinafter, the same components as those of embodiment 1 will be denoted by the same reference numerals and descriptions thereof will be omitted as appropriate.

(2) Details Hereinafter, the details of the discrimination system 1 according to this embodiment will be described with reference to FIG. 1 and FIGS.

(2.1) Configuration of the Discrimination System The overall configuration of the discrimination system 1 of this embodiment is similar to that of the discrimination system 1 shown in FIG.

As shown in FIG. 9, the directivity control unit 31 of this embodiment gradually increases the absolute value of the angle dθ1, which is the offset amount, until the degree of coincidence calculated by the calculation unit 6 becomes less than the threshold value Th1. In other words, the directivity control unit 31 of this embodiment gradually increases the absolute value of the angle dθ1 until the discrimination unit 7 determines that the target located in at least the first direction D1 and the object located in the second direction D2 are not the same.

In this embodiment, the first direction D1 is set in advance, and the angle θ1 (see FIG. 2A) of the first direction D1 is set to 20°. The directivity control unit 31 then switches the directivity of the multiple antennas 21 to the second direction D2, which is offset from the first direction D1 in the negative direction by an angle dθ1. The initial value of the offset amount, angle dθ1, is, for example, 5°. The directivity control unit 31 then increases the absolute value of the angle dθ1 by 5° until the discrimination unit 7 determines that the target located in the first direction D1 and the object located in the second direction D2 are not the same.

As described above, the directivity control unit 31 of this embodiment also offsets the angle in the opposite direction. That is, the directivity control unit 31 of this embodiment switches the directivities of the multiple antennas 21 between a second direction D2 offset by an angle dθ1 in the negative direction with respect to the first direction D1, and a second direction D2 offset by an angle dθ2 in the positive direction with respect to the first direction D1. Note that the initial value of the angle dθ2, which is the offset amount in the positive direction in this embodiment, is 5°. Furthermore, the directivity control unit 31 increases the absolute value of the angle dθ2 by 5° until the discrimination unit 7 determines that the target located in the first direction D1 and the object located in the second direction D2 are not the same.

As described above, the discrimination unit 7 of this embodiment repeatedly performs identity discrimination at least until it is determined that the target located in the first direction D1 and the object located in the second direction D2 are not the same. Note that the discrimination unit 7 of this embodiment repeatedly performs identity discrimination for each of the second direction D2 offset in the negative direction and the second direction D2 offset in the positive direction.

The size estimation unit 8 of this embodiment estimates the size of the target based on the range (angle) in which the discrimination unit 7 determines that the target located in the first direction D1 and the object located in the second direction D2 are the same. In the example of FIG. 9, when the angle of the second direction D2 is in the range from angle θ2 to angle θ3, the discrimination unit 7 determines that the target located in the first direction D1 and the object located in the second direction D2 are the same. Therefore, the size estimation unit 8 of this embodiment estimates the size of the target based on the distance r1 between the radio wave sensor 2 (see FIG. 2A) and the target, and the difference between the angles θ2 and θ3.

The type estimation unit 9 in this embodiment estimates the type of the target based on the result of size estimation by the size estimation unit 8.

(2.2) Operation of the Discrimination System Next, the operation of the discrimination system 1 will be described with reference to Fig. 10 and Fig. 11. Fig. 10 and Fig. 11 are flow charts showing the operation (discrimination process) of the discrimination system 1 of this embodiment.

First, the discrimination system 1 switches the directivity of the multiple antennas 21 to the first direction D1, which is the estimated direction of arrival of the reflected wave, and transmits radio waves (S21). Next, the discrimination system 1 receives the reflected wave from the first direction D1 with the multiple antennas 21 (S22). Next, the discrimination system 1 extracts the first biometric information from the reflected wave from the first direction D1 (S23). Next, the discrimination system 1 performs offset processing (S24). In the first offset processing, the discrimination system 1 offsets the first direction D1 by 5° to the negative side, and in the second and subsequent offset processing, it further offsets by 5° to the negative side. Then, the discrimination system 1 switches the directivity of the multiple antennas 21 to the second direction D2 after the offset processing (S24), and transmits radio waves (S25). Next, the discrimination system 1 receives the reflected wave from the second direction D2 with the multiple antennas 21 (S26). Next, the discrimination system 1 extracts the second biometric information from the reflected wave from the second direction D2 (S27). Next, the discrimination system 1 calculates the degree of coincidence between the first biometric information and the second biometric information (S28). Next, the discrimination system 1 determines whether the object located in the first direction D1 and the object located in the second direction D2 are the same based on the calculated degree of coincidence (S29). If the degree of coincidence is equal to or greater than the threshold value Th1, that is, if the object located in the first direction D1 and the object located in the second direction D2 are the same (S29: Yes), the process returns to step S24. Then, the discrimination system 1 repeats the processes of steps S24 to S29 until the object located in the first direction D1 and the object located in the second direction D2 are no longer the same.

On the other hand, if the degree of coincidence is less than the threshold value Th1, that is, if the object located in the first direction D1 is not the same as the object located in the second direction D2 (S29: No), the discrimination system 1 performs offset processing in the opposite direction (S30). In the first offset processing, the discrimination system 1 offsets the first direction D1 by 5° to the positive side, and in the second and subsequent offset processing, offsets the first direction D1 by another 5° to the positive side. Then, the discrimination system 1 switches the directivity of the multiple antennas 21 to the second direction D2 after the offset processing (S30) and transmits radio waves (S31). Next, the discrimination system 1 receives the reflected wave from the second direction D2 with the multiple antennas 21 (S32). Next, the discrimination system 1 extracts the second biometric information from the reflected wave from the second direction D2 (S33). Next, the discrimination system 1 calculates the degree of coincidence between the first biometric information and the second biometric information (S34). Next, the discrimination system 1 determines whether the object located in the first direction D1 is the same as the object located in the second direction D2 based on the calculated degree of coincidence (S35). If the degree of coincidence is equal to or greater than the threshold Th1, that is, if the object located in the first direction D1 is the same as the object located in the second direction D2 (S35: Yes), the process returns to step S30. Then, the discrimination system 1 repeats the processes of steps S30 to S35 until the object located in the first direction D1 is no longer the same as the object located in the second direction D2. On the other hand, if the degree of coincidence is less than the threshold Th1, that is, if the object located in the first direction D1 is not the same as the object located in the second direction D2 (S35: No), the discrimination system 1 estimates the size of the target (S36). Then, the discrimination system 1 estimates the type of the target based on the estimated size (S37) and ends the discrimination process.

(3) Effects As described above, the directivity control unit 31 of the present embodiment gradually increases the angle dθ1 (angle dθ2), which is the offset amount, until the degree of coincidence becomes less than the threshold value Th1. This clarifies the range of angles (widths) in which the target located in the first direction D1 and the object located in the second direction D2 are identical, thereby improving the accuracy of size and type estimation by the discrimination system 1.

In addition, the directivity control unit 31 of this embodiment also performs offsetting in the opposite direction. The discrimination system 1 determines whether a target located in the first direction D1 is identical to an object located in the second direction D2 offset from the first direction D1 to the negative and positive sides, thereby improving the accuracy of size and type estimation.

(4) Modifications The second embodiment is merely one of various embodiments of the present disclosure. The second embodiment can be modified in various ways depending on the design and the like as long as the object of the present disclosure can be achieved.

The various configurations described in embodiment 2 can be applied in appropriate combination with embodiment 1 and the modified version of embodiment 1.

(summary)
As described above, the discrimination system (1) according to the first aspect includes a radio wave sensor (2), a directivity control unit (31), an extraction unit (5), a calculation unit (6), and a discrimination unit (7). The radio wave sensor (2) has a plurality of antennas (21) that receive reflected waves of radio waves. The directivity control unit (31) switches the directivity of the plurality of antennas (21) between a first direction (D1) and a second direction (D2) that is offset by an angle (dθ1; dθ2) with respect to the first direction (D1). The extraction unit (5) extracts biometric information based on the reflected waves received by the radio wave sensor (2) from the first direction (D1) as the first biometric information, and extracts biometric information based on the reflected waves received by the radio wave sensor (2) from the second direction (D2) as the second biometric information. The calculation unit (6) calculates the degree of agreement between the first biometric information extracted by the extraction unit (5) and the second biometric information. The discrimination unit (7) discriminates whether an object located in the first direction (D1) and an object located in the second direction (D2) are the same by comparing the degree of similarity calculated by the calculation unit (6) with a threshold value.

According to this aspect, the discrimination system (1) can discriminate that an object located in the first direction (D1) and an object located in the second direction (D2) are different objects, and can therefore discriminate that there are multiple objects when multiple objects are present in close proximity to one another. This allows the discrimination system (1) to improve the accuracy of, for example, estimating the size of a target or estimating the type of the target.

The discrimination system (1) according to the second aspect is the first aspect, and further includes a size estimation unit (8). The size estimation unit (8) estimates the size of an object located in the first direction (D1) based on the discrimination result by the discrimination unit (7).

According to this aspect, the discrimination system (1) estimates the size of the target after determining whether the target located in the first direction (D1) and the object located in the second direction (D2) are the same or different, thereby improving the accuracy of estimating the size of the target.

In the discrimination system (1) according to the third aspect, in the second aspect, the size estimation unit (8) estimates the size of an object located in the first direction (D1) by comparing vital reference information associated with each size of the target with the biometric information.

According to this aspect, the size estimation unit (8) can improve the accuracy of size estimation by comparing the vital reference information with the biological information.

In the discrimination system (1) according to the fourth aspect, in any of the first to third aspects, the biological information includes at least one of primary information including at least one of a respiratory waveform and a heart rate waveform, and secondary information including at least one of a respiratory rate obtained from the respiratory waveform and a heart rate obtained from the heart rate waveform.

According to this aspect, the discrimination system (1) can improve the accuracy of identity discrimination by performing identity discrimination using biometric information that is different depending on the type of target, such as an adult and a child.

The discrimination system (1) according to the fifth aspect is any one of the first to fourth aspects, and further includes a direction estimation unit (4). The first direction (D1) is the direction of arrival estimated by the direction estimation unit (4).

According to this aspect, the discrimination system (1) is provided with a direction estimation unit (4), and therefore, even if the first direction (D1) is not set in advance, the direction in which the target (object) is located can be determined as the first direction (D1).

In the discrimination system (1) according to the sixth aspect, in any of the first to fifth aspects, the directivity control unit (31) gradually increases the offset angle (dθ1; dθ2) until the degree of coincidence becomes less than the threshold value.

According to this aspect, the range of angles (widths) in which a target located in the first direction (D1) and an object located in the second direction (D2) are the same becomes clear, improving the accuracy of size and type estimation by the discrimination system (1).

In the discrimination system (1) according to the seventh aspect, in any of the first to fifth aspects, the angle (dθ1; dθ2) by which the directivity control unit (31) is offset is preset according to the distance between the radio wave sensor (2) and the target.

According to this embodiment, the offset amount, ie, the angle (dθ1; dθ2), is preset, thereby reducing the processing load on the discrimination system (1).

In the discrimination system (1) according to the eighth aspect, in any of the first to seventh aspects, the directivity control unit (31) also performs offsetting in the opposite direction.

According to this aspect, the discrimination system (1) discriminates whether a target located in a first direction (D1) is identical to an object located in a second direction (D2) offset from the first direction (D1) to the negative and positive sides, thereby improving the accuracy of size and type estimation.

In the discrimination system (1) according to the ninth aspect, in the first to eighth aspects, the calculation unit (6) calculates the degree of agreement based on the correlation between the first biometric information and the second biometric information.

According to this aspect, when calculating the degree of similarity using, for example, a heart rate waveform or a respiratory waveform, the calculation unit (6) calculates the degree of similarity based on cross-correlation, thereby improving the accuracy of calculating the degree of similarity.

In the discrimination system (1) according to the tenth aspect, in the first to ninth aspects, the radio wave sensor (2) has, as the multiple antennas (21), multiple antennas (21) arranged in a first arrangement direction (Ar1) and multiple antennas (21) arranged in a second arrangement direction (Ar2) intersecting the first arrangement direction (Ar1).

According to this aspect, the discrimination system (1) can, for example, set the offset amount, ie, angle (dθ1; dθ2), in the azimuth direction and in the elevation and depression directions.

Configurations other than the first aspect are not essential to the discrimination system (1) and may be omitted as appropriate.

The discrimination method according to the eleventh aspect includes a directivity control step, an extraction step, a calculation step, and a discrimination step. In the directivity control step, the directivity of the multiple antennas (21) that receive the reflected waves of the radio waves is switched between a first direction (D1) and a second direction (D2) offset by an angle (dθ1; dθ2) with respect to the first direction (D1). In the extraction step, the multiple antennas (21) extract biometric information based on the reflected waves received from the first direction (D1) as the first biometric information, and the multiple antennas (21) extract biometric information based on the reflected waves received from the second direction (D2) as the second biometric information. In the calculation step, the degree of agreement between the first biometric information extracted in the extraction step and the second biometric information is calculated. In the discrimination step, the degree of agreement calculated in the calculation step is compared with a threshold value to discriminate whether an object located in the first direction (D1) and an object located in the second direction (D2) are the same or not.

According to this aspect, since it is possible to determine that an object located in the first direction (D1) and an object located in the second direction (D2) are different objects, it is possible to determine that there are multiple objects when multiple objects exist in close proximity to each other. This allows the discrimination system (1) to improve the accuracy of, for example, estimating the size of a target or estimating the type of the target.

The program according to the twelfth aspect is a program for causing one or more processors to execute the determination method according to the eleventh aspect.

According to this aspect, by determining whether an object located in the first direction (D1) and an object located in the second direction (D2) are the same, it is possible to improve the accuracy of, for example, estimating the size or type of a target.

REFERENCE SIGNS LIST 1 Discrimination system 2 Radio wave sensor 21 Antenna 31 Directivity control unit 4 Direction estimation unit 5 Extraction unit 6 Calculation unit 7 Discrimination unit 8 Size estimation unit Ar1 First array direction Ar2 Second array direction D1 First direction D2 Second direction dθ1, dθ2 Angles T1, T2 Target

Claims (12)

a radio wave sensor having a plurality of antennas for transmitting radio waves and receiving reflected waves of the radio waves;
a directivity control unit that switches the directivities of the plurality of antennas between a first direction and a second direction that is an angle offset with respect to the first direction;
an extracting unit that extracts, as first biometric information, biometric information based on the reflected wave received by the radio wave sensor from the first direction, and extracts, as second biometric information, the biometric information based on the reflected wave received by the radio wave sensor from the second direction;
a calculation unit that calculates a degree of agreement between the first biometric information and the second biometric information extracted by the extraction unit;
a determination unit that determines whether or not an object located in the first direction and an object located in the second direction are the same by comparing the degree of coincidence calculated by the calculation unit with a threshold value ,
The biological information includes at least one of information regarding heart rate and information regarding respiration.
Discrimination system. a size estimation unit that estimates a size of the object located in the first direction based on a result of the determination by the determination unit,
The discrimination system according to claim 1 . the size estimation unit compares the biological information with vital reference information in which a vital reference value is associated with each size of the target, and estimates the size of the object located in the first direction.
The discrimination system according to claim 2 . The biological information includes at least one of primary information including at least one of a respiratory waveform and a heart rate waveform, and secondary information including at least one of a respiratory rate obtained from the respiratory waveform and a heart rate obtained from the heart rate waveform.
The discrimination system according to any one of claims 1 to 3. A direction estimator that estimates a direction of arrival of the reflected wave based on a phase difference of the reflected wave received by the plurality of antennas,
The first direction is the arrival direction estimated by the direction estimation unit.
The discrimination system according to any one of claims 1 to 4. The directivity control unit gradually increases the offset angle until the degree of coincidence becomes less than a threshold value.
The discrimination system according to any one of claims 1 to 5. The angle at which the directivity control unit offsets is preset according to the distance between the radio wave sensor and a target.
The discrimination system according to any one of claims 1 to 5. The directivity control unit also performs the offset in the opposite direction.
The discrimination system according to any one of claims 1 to 7. the calculation unit calculates the degree of agreement based on a correlation between the first biometric information and the second biometric information.
The discrimination system according to any one of claims 1 to 8. The radio wave sensor has, as the plurality of antennas, a plurality of antennas arranged in a first arrangement direction and a plurality of antennas arranged in a second arrangement direction intersecting the first arrangement direction.
The discrimination system according to any one of claims 1 to 9. a directivity control step of switching the directivities of a plurality of antennas that transmit radio waves and receive reflected waves of the radio waves between a first direction and a second direction that is an angle offset from the first direction;
an extraction step of extracting, as first biometric information, biometric information based on the reflected waves received by the plurality of antennas from the first direction, and extracting, as second biometric information, biometric information based on the reflected waves received by the plurality of antennas from the second direction;
a calculation step of calculating a degree of coincidence between the first biometric information extracted in the extraction step and the second biometric information;
a determination step of determining whether or not the object located in the first direction and the object located in the second direction are the same by comparing the degree of coincidence calculated in the calculation step with a threshold value;
having
The biological information includes at least one of information regarding heart rate and information regarding respiration.
How to determine: A program for causing one or more processors to execute the determination method according to claim 11.

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