Vital Sign Detection Device, Vehicle, and Vital Sign Detection Method

Abstract

The present invention provides a vital sign detection device and a vital sign detection method, which can always accurately extract the vital signs of a subject only, even when the body type and posture of the subject change, and improve the degree of freedom in design and suppress costs. The directivities of radio waves (A) and (B) emitted from one irradiation unit (11) to the subject (3) are changed to a first directivity and a second directivity by the control of the scanning unit (12) by the control unit (15), and the radio waves (A) and (B) are irradiated from the irradiation unit (11) to each irradiation area where the vital signs of the subject (3) are likely to appear and difficult to appear. By using the vital sign extraction unit (16) to obtain the difference between the distance information to the subject (3) calculated based on the radio wave (A) of the first directivity received by the receiving unit (13) and the distance information to the subject (3) calculated based on the radio wave B of the second directivity received by the receiving unit (13), the noise included in the vital signs of the subject (3) is removed, and the vital signs of the subject (3) are accurately extracted.

Description

Technical Field

[0001] The present invention relates to a vital sign detection device, a vehicle, and a vital sign detection method for detecting the vital signs of a subject. Background Art

[0002] Conventionally, as such a vital sign detection device and a vital sign detection method, for example, there is the content disclosed in Patent Document 1. In this vital sign detection device and detection method, a determination unit determines a measurement site as a determination site suitable for the detection of vital signs, and the frequency analysis result related to the reflected wave of the electromagnetic wave irradiated to the subject represents the frequency characteristics in a physical condition where the vital signs of the subject are strongly expressed. Further, a control unit controls the scanning of the irradiation area of the electromagnetic wave so that the electromagnetic wave is irradiated to the determination site determined by the determination unit. A detection unit detects the vital signs of the subject based on the analysis result of the reflected wave received at the determination site determined by the determination unit.

[0003] In addition, conventionally, as such a vital sign detection device, for example, there is also a biological sensor disclosed in Patent Document 2. In this biological sensor, two sets of non-contact sensors for detecting the biological information of a person by electromagnetic waves are provided with respect to a seat on which a person is seated. Each set of biological sensors is configured by adjacently arranging a first sensor and a second sensor that emit electromagnetic waves of different frequencies to the person. Either the first sensor or the second sensor is used to detect biological information including noise elements, and the other is used to detect noise elements. The biological information of the subject is extracted by taking the difference in the amount of noise elements.

[0004] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2019-115464

[0005] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2019-180451

[0006] However, the above-described conventional vital sign detection device and vital sign detection method disclosed in Patent Document 1 are configured to determine a measurement site where the vital signs of the subject are strongly expressed and detect the vital signs of the subject only based on this measurement site. Therefore, in the vital signs of the subject to be detected, there are noises such as the body movement of the subject superimposed on the measurement site where the vital signs of the subject are strongly expressed, and the vital signs of the subject cannot be correctly detected.

[0007] In addition, in the above-described conventional biosensor disclosed in Patent Document 2, the amount of noise elements detected by the other sensor is obtained as a difference from the biological information containing noise elements detected by either the first sensor or the second sensor included in the biosensor, thereby correctly extracting the vital signs of the subject. However, if the body shape or posture of the subject changes, the irradiation sites of the respective electromagnetic waves irradiated from the first sensor and the second sensor to the subject change, and there is a case where the electromagnetic waves do not irradiate the sites where biological information is likely to appear. In such a case, even if the difference in the information detected by each sensor is obtained, the vital signs of the subject cannot be correctly extracted. In addition, the first sensor and the second sensor must be arranged adjacent to each other, so that the space occupied by the biosensor increases in a vehicle seat or the like where the biosensor is provided. Therefore, the place where the biosensor is arranged in a vehicle seat or the like is limited, and the degree of freedom in design is reduced. In addition, since multiple sensors such as the first sensor and the second sensor are used, the cost of the device increases. Summary of the Invention

[0008] The present invention has been completed to solve such problems, and a vital sign detection device is configured with the following components: an irradiation unit that emits electromagnetic waves to a subject; a scanning unit that scans an irradiation area of the electromagnetic waves irradiated to the subject by changing the directivity of the electromagnetic waves emitted from the irradiation unit; a receiving unit that receives the electromagnetic waves reflected by the subject; a directivity determination unit that determines a first directivity of the electromagnetic waves that irradiates an irradiation area where the vital signs of the subject are likely to appear and a second directivity of the electromagnetic waves that irradiates an irradiation area where the vital signs of the subject are unlikely to appear based on the reception result of the electromagnetic waves in the receiving unit; a control unit that controls the scanning of the electromagnetic waves performed when the first directivity and the second directivity are determined by the directivity determination unit for the scanning unit and controls the directivity of the electromagnetic waves irradiated to the subject to be the first directivity or the second directivity determined by the directivity determination unit; and a vital sign extraction unit that extracts the vital signs of the subject based on the difference between the distance information from the vital sign detection device to the irradiation site of the electromagnetic waves irradiated to the subject calculated based on the electromagnetic waves of the first directivity reflected by the subject and received by the receiving unit and the distance information from the vital sign detection device to the irradiation site of the electromagnetic waves irradiated to the subject calculated based on the electromagnetic waves of the second directivity reflected by the subject and received by the receiving unit.

[0009] In addition, the present invention is configured with the following steps to form a vital sign detection method:

[0010] An electromagnetic wave scanning step of scanning an irradiation area of the electromagnetic waves irradiated to the subject by the scanning unit by changing the directivity of the electromagnetic waves irradiated from the irradiation unit to the subject;

[0011] A directivity determination step, in which a directivity determination unit determines a first directivity of electromagnetic waves that irradiate an irradiation area where the vital signs of the subject are likely to appear and a second directivity of electromagnetic waves that irradiate an irradiation area where the vital signs of the subject are less likely to appear, based on the reception result of the electromagnetic waves that are scanned in the electromagnetic wave scanning step, hit the subject, are reflected, and are received by the receiving unit;

[0012] An electromagnetic wave irradiation step, in which electromagnetic waves having the first directivity and the second directivity determined in the directivity determination step are emitted from the irradiation unit to the subject, so that the electromagnetic waves irradiate an irradiation area where the vital signs of the subject are likely to appear and an irradiation area where the vital signs of the subject are less likely to appear;

[0013] A vital sign extraction step, in which the vital signs of the subject are extracted based on the difference between the distance information from the vital sign detection device to the irradiation site where the electromagnetic waves are irradiated to the subject calculated from the electromagnetic waves of the first directivity reflected by the subject and received by the receiving unit and the distance information from the vital sign detection device to the irradiation site where the electromagnetic waves are irradiated to the subject calculated from the electromagnetic waves of the second directivity reflected by the subject and received by the receiving unit;

[0014] A comparison step, in which the magnitude of the vital signs of the subject extracted in the vital sign extraction step is compared with a specified threshold value; and

[0015] A vital sign re-extraction step, in which, when the comparison result in the comparison step is that the magnitude of the vital signs of the subject extracted in the vital sign extraction step does not exceed the specified threshold value, the electromagnetic wave scanning step, the directivity determination step, the electromagnetic wave irradiation step, and the vital sign extraction step are repeatedly executed.

[0016] According to this structure, the directivity of the electromagnetic waves emitted from one irradiation unit to the subject is changed to the first directivity and the second directivity by the control of the control unit over the scanning unit, and the electromagnetic waves are irradiated to an irradiation area where the vital signs of the subject are likely to appear and an irradiation area where the vital signs of the subject are less likely to appear. By obtaining, by the vital sign extraction unit, the difference between the distance information from the vital sign detection device to the irradiation site where the electromagnetic waves are irradiated to the subject calculated from the electromagnetic waves of the first directivity reflected by the subject and received by the receiving unit and the distance information from the vital sign detection device to the irradiation site where the electromagnetic waves are irradiated to the subject calculated from the electromagnetic waves of the second directivity reflected by the subject and received by the receiving unit, the noise included in the vital signs of the subject is removed, and the vital signs of the subject are accurately extracted.

[0017] In addition, even if the body shape and posture of the subject change, the directivity of the electromagnetic wave emitted from the irradiation unit to the subject is changed by the control unit's control of the scanning unit to the first directivity of the electromagnetic wave that irradiates the irradiation area where the vital signs of the subject are likely to appear and the second directivity of the electromagnetic wave that irradiates the irradiation area where the vital signs of the subject are difficult to appear. Therefore, even if the body shape and posture of the subject change, the electromagnetic wave emitted from the irradiation unit to the subject is irradiated to the irradiation area where the vital signs of the subject are likely to appear and the irradiation area where the vital signs of the subject are difficult to appear. The noise included in the vital signs of the subject is removed by the vital sign extraction unit, and only the vital signs of the subject are accurately extracted.

[0018] In addition, since the vital signs of the subject are accurately extracted as described above using one irradiation unit, the space occupied by the vital sign detection device at its installation site can be suppressed, the width of the selection of the installation site of the vital sign detection device is widened, and the degree of freedom in design is improved. In addition, the cost of the vital sign detection device can also be suppressed.

[0019] In addition, the present invention is configured as a vital sign detection device having the following components:

[0020] An irradiation unit that emits an electromagnetic wave to the subject;

[0021] A scanning unit that scans the irradiation area of the electromagnetic wave irradiated to the subject by changing the directivity of the electromagnetic wave emitted from the irradiation unit;

[0022] A receiving unit that receives a plurality of electromagnetic waves with different directivities that are reflected by hitting the subject; and

[0023] A vital sign extraction unit that extracts the vital signs of the subject using the difference between the distance information of the subject calculated based on the electromagnetic wave with the strongest signal intensity representing the vital signs of the subject among the plurality of electromagnetic waves received by the receiving unit and the distance information of the subject calculated based on the electromagnetic wave with the strongest signal intensity other than the vital signs of the subject.

[0024] In addition, the present invention is configured as a vital sign detection method having the following steps:

[0025] An electromagnetic wave scanning step of scanning the irradiation area of the electromagnetic wave to the subject by the scanning unit by changing the directivity of the electromagnetic wave irradiated from the irradiation unit to the subject;

[0026] An electromagnetic wave receiving step of receiving a plurality of electromagnetic waves with different directivities that are scanned in the electromagnetic wave scanning step, reflected by hitting the subject, and received by the receiving unit;

[0027] A vital sign extraction step, which uses the difference between the distance information of the subject calculated based on the electromagnetic wave with the strongest signal intensity representing the vital signs of the subject among the multiple electromagnetic waves received by the receiving unit, and the distance information of the subject calculated based on the electromagnetic wave with the strongest signal intensity other than the vital signs of the subject, to extract the vital signs of the subject;

[0028] A comparison step, which compares the magnitude of the vital signs of the subject extracted in the vital sign extraction step with a specified threshold value; and

[0029] A vital sign re-extraction step, which repeatedly executes the electromagnetic wave scanning step, the electromagnetic wave receiving step, and the vital sign extraction step when the comparison result in the comparison step indicates that the magnitude of the vital signs of the subject extracted in the vital sign extraction step does not exceed the specified threshold value.

[0030] According to this structure, the directivity of the electromagnetic wave emitted from one irradiation unit to the subject is changed to multiple directivities, and the electromagnetic wave is irradiated from the irradiation unit. The electromagnetic wave irradiated from the irradiation unit is received by the receiving unit as an electromagnetic wave with multiple directivities. Moreover, in the vital sign extraction unit, by obtaining the difference between the distance information of the subject calculated based on the electromagnetic wave with the strongest signal intensity representing the vital signs of the subject among the multiple electromagnetic waves received by the receiving unit and the distance information of the subject calculated based on the electromagnetic wave with the strongest signal intensity other than the vital signs of the subject, the noise contained in the vital signs of the subject is removed, and the vital signs of the subject are accurately extracted.

[0031] In addition, even if the body shape and posture of the subject change, by using the scanning unit to change the directivity of the electromagnetic wave emitted from the irradiation unit to the subject, the electromagnetic wave with new multiple directivities is also received by the receiving unit. Moreover, in the vital sign extraction unit, by obtaining the difference between the distance information of the subject calculated based on the new multiple electromagnetic waves received by the receiving unit, the distance information of the subject calculated based on the electromagnetic wave with the strongest signal intensity representing the vital signs of the subject and the distance information of the subject calculated based on the electromagnetic wave with the strongest signal intensity other than the vital signs of the subject, the noise contained in the vital signs of the subject is removed, and the new vital signs of the subject are accurately extracted. Therefore, even if the body shape and posture of the subject change, the vital signs of the subject are accurately extracted.

[0032] In addition, in this structure, since one irradiation unit is also used to accurately extract the vital signs of the subject as described above, the space occupied by the vital sign detection device in its installation location can be suppressed, the width of the selection of the installation location of the vital sign detection device becomes wider, and the degree of freedom in design is improved. In addition, the cost of the vital sign detection device can also be suppressed.

[0033] According to the present invention, it is possible to provide a vital sign detection device and a vital sign detection method that can remove noise included in the vital signs of a subject even when the body shape and posture of the subject change, always accurately extract only the vital signs of the subject, and improve the degree of freedom in design and suppress costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 FIG. 6 is a schematic side view showing a state in which a subject is seated on a seat in a vehicle in the vital sign detection device and the vital sign detection method according to the first embodiment of the present invention.

[0035] Figure 2 FIG. 10 is a block diagram showing a schematic configuration of the vital sign detection device according to the first embodiment of the present invention.

[0036] Figure 3 FIG. 14 is a schematic flowchart showing a rough process of the vital sign detection method according to the first embodiment of the present invention.

[0037] Figure 4 FIG. 18 is a detailed flowchart showing a detailed process of the vital sign detection method according to the first embodiment of the present invention.

[0038] Figure 5 FIG. 22 is a graph for detecting the vital signs of a subject by detecting the body surface displacement of the subject calculated in the vital sign detection device and the vital sign detection method according to the first embodiment of the present invention.

[0039] Figure 6 FIG. 26 is a schematic side view showing a state in which a subject is seated on a seat in a vehicle in the vital sign detection device and the vital sign detection method according to the second embodiment of the present invention.

[0040] Figure 7 FIG. 30 is a flowchart showing an outline of the vital sign detection method using the vital sign detection device according to the fourth embodiment of the present invention.

[0041] Figure 8 (a) of FIG. 34 is a perspective view showing the interior of a vehicle with the vital sign detection device of each embodiment arranged at various positions, and (b) is a perspective view showing the interior of a hospital ward with the vital sign detection device of each embodiment arranged at various positions. DETAILED DESCRIPTION OF THE INVENTION

[0042] Next, a mode for implementing the vital sign detection device, the vehicle, and the vital sign detection method of the present invention will be described.

[0043] Figure 1FIG. 0 is a schematic side view of the state in which the vital sign detection device 1 and the vital sign detection method according to the first embodiment of the present invention are used as a driver monitoring system (DMS), and the subject 3 is seated on the seat 2 in the vehicle. The vital sign detection device 1 and the vital sign detection method according to the present embodiment detect the body surface displacement of the subject 3, which is an index of vital signs such as the heart rate, heart rate variability, respiratory rate, and depth of respiration of the subject 3 driving the vehicle, that is, the change in the distance from the vital sign detection device 1 to the body surface of the irradiation site that irradiates the subject 3 with electromagnetic waves, as vital signs.

[0044] The vital sign detection device 1 according to the first embodiment is disposed inside the seat 2, and a schematic structure is shown in the block diagram of Figure 2 . The vital sign detection device 1 includes an irradiation unit 11, a scanning unit 12, a receiving unit 13, a directivity determination unit 14, a control unit 15, and a vital sign extraction unit 16. These units are implemented by software control processing of a microcomputer, or by a hardware structure of an electronic circuit, or by both the software control processing of the microcomputer and the hardware structure of the electronic circuit. Generally, the irradiation unit 11 is configured as an antenna, and the scanning unit 12, the receiving unit 13, the directivity determination unit 14, the control unit 15, and the vital sign extraction unit 16 are configured as ICs (integrated circuits).

[0045] The irradiation unit 11 is composed of a Doppler radar, an FMCW (Frequency Modulated Continuous Wave radar) radar, etc., which have one or more transmitting antennas and a transmitter that emits radio waves from the transmitting antenna. The irradiation unit 11, the scanning unit 12, the receiving unit 13, the directivity determination unit 14, and the control unit 15 except for the vital sign extraction unit 16 constitute these radars. The antenna is composed of an antenna using a radio wave lens, a patch antenna formed by a conductor pattern on a circuit board, etc. In the present embodiment, the electromagnetic wave emitted from the irradiation unit 11 is described as a radio wave, and the electromagnetic wave widely includes sound waves, light waves, etc. The scanning unit 12 scans the irradiation area of the radio wave irradiated to the subject 3 by changing the directivity of the radio wave emitted from the irradiation unit 11. Therefore, the irradiation unit 11 has a structure that emits an electromagnetic wave and makes the directivity of the emitted electromagnetic wave variable.

[0046] By changing the phase / amplitude of the radio wave emitted from the irradiation unit 11 through analog beamforming, or by changing the phase / amplitude of the radio wave received by the receiving unit 13 through digital beamforming by control / calculation, the directivity of the radio wave emitted from the irradiation unit 11 is changed. In the analog beamforming method, the directivity of the radio wave emitted from the irradiation unit 11 is changed by the phase / amplitude information of the radio wave received by the irradiation unit 11 from the scanning unit 12 or the control unit 15. In the digital beamforming method, the phase / amplitude of the radio wave received by the receiving unit 13 is calculated by the control unit 15 or the scanning unit 12, so that the same effect as changing the directivity of the radio wave emitted from the irradiation unit 11 can be obtained.

[0047] The receiving unit 13 includes one or more receiving antennas, and receives the radio wave that is scanned by the scanning unit 12 and reflected by the subject 3. The directivity determination unit 14 determines the first directivity of the radio wave for irradiating the irradiation area where the vital signs of the subject 3 are likely to appear and the second directivity of the radio wave for irradiating the irradiation area where the vital signs of the subject 3 are difficult to appear based on the reception result of the radio wave in the receiving unit 13. In Figure 1 Radio wave A having the first directivity and radio wave B having the second directivity are illustrated. In the present embodiment, the respective frequency bands of radio wave A having the first directivity and radio wave B having the second directivity are set to be the same.

[0048] The receiving unit 13 includes a calculation unit that calculates the difference between the distance information from the vital sign detection device 1 to the irradiation site for irradiating the subject 3 with the electromagnetic wave calculated based on the first directivity electromagnetic wave reflected by the subject 3 and received by the receiving unit 13 and the distance information from the vital sign detection device 1 to the irradiation site for irradiating the subject 3 with the electromagnetic wave calculated based on the second directivity electromagnetic wave reflected by the subject 3 and received by the receiving unit 13, as the body surface displacement of the subject 3. The directivity determination unit 14 includes: a candidate determination unit that determines the irradiation directions of the electromagnetic waves that are candidates for the first directivity and the second directivity, and instructs the control unit 15 to make the irradiation direction of the electromagnetic wave emitted from the irradiation unit 11 be the determined irradiation direction; and a direction determination unit that determines the first directivity and the second directivity, and instructs the control unit 15 to make the directivity of the electromagnetic wave emitted from the irradiation unit 11 be the determined first directivity and second directivity.

[0049] The candidate determination unit determines, for each candidate of the first directivity and the second directivity, the irradiation range of the electromagnetic wave emitted from the irradiation unit 11 to the subject 3 and the magnitude of the scanning angle for scanning the electromagnetic wave within the irradiation range. For example, for a candidate of the first directivity, within the irradiation range of the electromagnetic wave of ±30° with respect to the direction of the main lobe of the irradiation unit 11 as a reference, the scanning angle is determined to be 1°. In this case, the electromagnetic wave is irradiated and scanned in the directions of +30°, +29°, +28°, … with respect to the direction of the main lobe of the irradiation unit 11, for example. For a candidate of the second directivity, an irradiation range different from the irradiation range of the electromagnetic wave determined for the candidate of the first directivity and the magnitude of the scanning angle for scanning the electromagnetic wave within the irradiation range are determined. Then, the candidate determination unit instructs the control unit 15 to emit the electromagnetic wave from the irradiation unit 11 with the determined irradiation range and the magnitude of the scanning angle.

[0050] The direction determination unit compares a plurality of received waveforms of the electromagnetic wave that is irradiated in the irradiation direction of the candidate determined to be the first directivity by the candidate determination unit, hits the subject 3, and is received by the receiving unit 13 with a model waveform of the electromagnetic wave having the first directivity prepared in advance, calculates the similarity between each received waveform and the model waveform, and determines the first directivity. The waveform of the electromagnetic wave having the first directivity becomes a waveform that has a generally similar tendency regardless of who the subject 3 is, and thus this general waveform is set as the model waveform. In addition, the calculation of the similarity between the model waveform and each received waveform is performed using waveform comparison methods such as the dynamic time warping method and the cross correlation function. The directivity of the electromagnetic wave of the received waveform having the highest similarity to the model waveform is determined to be the first directivity.

[0051] The control unit 15 controls the scanning of the radio wave performed when the directivity determination unit 14 determines the first directivity and the second directivity for the scanning unit 12, and controls to make the radio wave irradiated to the subject 3 be the first directivity or the second directivity determined by the directivity determination unit 14. Through this control by the control unit 15 on the scanning unit 12, the radio wave A and the radio wave B are irradiated from the irradiation unit 11 to the subject 3 at a prescribed time interval within a prescribed irradiation time. The prescribed irradiation time is set, for example, to several 10 μsec to a certain value, and the prescribed time interval is set, for example, to a certain value to about 10 msec. If the prescribed time interval is set to a certain value, each of the radio waves A and B is continuously emitted from the irradiation unit 11. There is also a case where the radio waves A and B are emitted simultaneously, and there is also a case where they are emitted while being switched. The vital sign extraction unit 16 extracts the vital signs of the subject 3 based on the difference calculated by the calculation unit of the receiving unit 13 between the distance information from the vital sign detection device 1 to the irradiation site of the electromagnetic wave irradiated to the subject 3 calculated based on the radio wave A of the first directivity reflected by the subject 3 and received by the receiving unit 13 and the distance information from the vital sign detection device 1 to the irradiation site of the electromagnetic wave irradiated to the subject 3 calculated based on the radio wave B of the second directivity reflected by the subject 3 and received by the receiving unit 13.

[0052] Figure 3 It is a schematic flow chart showing the rough processing of the vital sign detection method of the first embodiment.

[0053] When detecting the vital signs of the subject 3, first, in Figure 3 step (hereinafter referred to as S) 101, a radio wave scanning step is performed. In this radio wave scanning step, by the control of the control unit 15 on the scanning unit 12, the directivity of the radio wave irradiated from the irradiation unit 11 to the subject 3 is changed, and thus the irradiation area of the radio wave irradiated to the subject 3 is scanned by the scanning unit 12. This scanning is performed with the irradiation range of the electromagnetic wave emitted from the irradiation unit 11 to the subject 3 determined by the candidate determination unit of the directivity determination unit 14 and the size of the scanning angle for scanning the electromagnetic wave within this irradiation range. Next, in the directivity determination step of S102, the first directivity of the radio wave A for irradiating the radio wave to the irradiation area where the vital signs of the subject 3 are likely to appear and the second directivity of the radio wave for irradiating the radio wave to the irradiation area where the vital signs of the subject 3 are difficult to appear are determined by the direction determination unit of the directivity determination unit 14. The determination of this directivity is performed based on calculating the similarity between the waveform of the received radio wave and the model waveform based on the reception result of the radio wave scanned in the radio wave scanning step of S101, reflected by hitting the subject 3, and received by the receiving unit 13.

[0054] Next, in the radio wave irradiation step of S103, radio waves A and B having the first directivity and the second directivity determined in the above-mentioned directivity determination step are emitted from the irradiation unit 11 to the subject 3 at the above-mentioned specified irradiation time and specified time interval, so that the radio waves are irradiated to the irradiation area where the vital signs of the subject 3 are likely to appear and the irradiation area where the vital signs of the subject 3 are difficult to appear. Next, in the vital sign extraction step of S104, based on the distance information to the subject 3 calculated from the radio wave A with the first directivity reflected by the subject 3 and received by the receiving unit 13, and the difference between the distance information to the subject calculated from the radio wave B with the second directivity reflected by the subject 3 and received by the receiving unit 13, the surface displacement of the subject 3 is detected, and the vital signs of the subject 3 are extracted.

[0055] Next, in the comparison step of S105, the magnitude of the vital signs of the subject 3 extracted in the above-mentioned vital sign extraction step is compared with a specified threshold value. When the magnitude of the vital signs of the subject 3 is equal to or greater than the specified threshold value and the comparison result in S105 is "yes", the process returns to the process of S104, and the process of S104 is repeated. On the other hand, when the magnitude of the vital signs of the subject 3 does not exceed the specified threshold value, the process returns to the process of S101, and the radio wave scanning step of S101, the directivity determination step of S102, the radio wave irradiation step of S103, and the vital sign extraction step of S104 are repeatedly executed to perform the vital sign re-extraction step. Through this vital sign re-extraction step, scanning is performed for all scanning angles in the irradiation range of the electromagnetic wave emitted from the irradiation unit 11 to the subject 3 determined by the candidate determination unit of the directivity determination unit 14.

[0056] Figure 4 It is a detailed flowchart showing the detailed processing of the vital sign detection method according to the first embodiment.

[0057] When extracting the vital signs of the subject 3, specifically, first, Figure 4 S201 is performed. In this S201, by the directivity determination unit 14, for each of the first directivity of the radio wave A irradiated to the irradiation area where the vital signs of the subject 3 are likely to appear and the second directivity of the radio wave B irradiated to the irradiation area where the vital signs of the subject 3 are difficult to appear, a plurality of candidates are determined by the above-mentioned candidate determination unit. The determination of the candidates can determine the candidates independently for each of the first directivity and the second directivity, or can determine the candidates as a combination of the first directivity and the second directivity.

[0058] Next, in S202, through the control of the scanning unit 12 by the control unit 15, radio waves are emitted from the irradiation unit 11 to the subject 3 in the directionality of one candidate determined by the candidate determination unit among the multiple candidates for the first directivity and the second directivity. Next, in S203, based on the radio waves A and B of the first directivity and the second directivity that are reflected by the subject 3 and received by the receiving unit 13, for each directivity, the receiving unit 13 calculates the body surface displacement of the subject 3, that is, the change in the distance from the vital sign detection device 1 to the body surface of the irradiation site where electromagnetic waves are irradiated to the subject 3.

[0059] Next, in S204, it is determined whether the body surface displacement of the subject 3 has been calculated for all the multiple candidates of each directivity determined in S201. If the body surface displacement of the subject 3 has not been calculated for all the multiple candidates of each directivity and the determination result in S204 is "no", the process returns to S202, and the processes of S202 and S203 are repeated. Through this repeated process, the body surface displacement of the subject 3 is calculated for all the multiple candidates of each directivity.

[0060] If the body surface displacement of the subject 3 has been calculated for all the multiple candidates of each directivity and the determination result in S204 is "yes", then the process of S205 is performed next. In the process of S205, through the directivity determination unit 14, among the multiple body surface displacements of the subject 3 calculated for the radio wave A of the first directivity of the multiple candidates, the directivity of the radio wave A with the strongest body surface displacement that generates the characteristics of vital signs, that is, the directivity of the radio wave A with the highest similarity to the model waveform, is determined as the first directivity of the irradiation area where the radio wave A is irradiated to the subject 3 to easily show the vital signs. In addition, through the directivity determination unit 14, among the multiple body surface displacements of the subject 3 calculated for the radio wave B of the second directivity of the multiple candidates, the directivity of the radio wave B with the strongest body surface displacement that generates the characteristics of noise such as the body movement of the subject 3 and the vibration of the vehicle is determined as the second directivity of the irradiation area where the radio wave B is irradiated to the subject 3 to make it difficult to show the vital signs.

[0061] Next, in S206, through the control of the scanning unit 12 by the control unit 15, the radio wave A with the first directivity determined as above and the radio wave B with the second directivity determined as above are emitted from the irradiation unit 11 toward the subject 3. Next, in S207, based on the radio waves A and B of the first directivity and the second directivity that are reflected by the subject 3 and received by the receiving unit 13, for each directivity, the receiving unit 13 calculates the body surface displacement of the subject 3.

[0062] It is considered that the body surface displacement of the subject 3 calculated from the first-directional radio wave A irradiated to the irradiation area where the vital signs of the subject 3 are likely to appear and received by the receiving unit 13 includes both the vital signs of the subject 3 and noises such as the body movement of the subject 3 and the vibration of the vehicle. In addition, it is considered that the body surface displacement of the subject 3 calculated from the second-directional radio wave B irradiated to the irradiation area where the vital signs of the subject 3 are difficult to appear and received by the receiving unit 13 does not include the vital signs of the subject 3, but only includes noises such as the body movement of the subject 3 and the vibration of the vehicle. Therefore, next, in S208, the difference in the body surface displacement of the subject 3 calculated for the first direction and the second direction is obtained, and the vital signs of the subject 3 are extracted.

[0063] The difference in the body surface displacement is calculated by subtracting the body surface displacement of the subject 3 calculated from the second-directional radio wave B received by the receiving unit 13 from the body surface displacement of the subject 3 calculated from the first-directional radio wave A received by the receiving unit 13. In addition, a Kalman filter and a filter are applied to the body surface displacement of the subject 3 calculated from each of the radio waves A and B, and the surge signal that suddenly appears in the body surface displacement is dulled, or the average value of the body surface displacement over a certain period of time is taken, and then the above subtraction operation is performed, and the difference in the body surface displacement can also be calculated. In addition, by using a sound source separation method such as independent component analysis or independent vector analysis, the body movement, vibration, and vital signs are separated from each of the radio waves A and B, and the difference in the body surface displacement of the subject 3 can also be obtained.

[0064] Figure 5 It is a graph showing the time changes of the body surface displacement of the subject 3 calculated from the first-directional radio wave A determined in the process of S205, the body surface displacement of the subject 3 calculated from the second-directional radio wave B determined in the process of S205, and the difference in these body surface displacements. The horizontal axis of this graph is time [seconds], and the vertical axis represents the displacement amount [μm] of the body surface displacement of the subject 3. The displacement amount of this body surface displacement represents the average value in a certain time period as 0. In addition, the characteristic line 21 shown by the dashed line represents the body surface displacement of the subject 3 calculated from the first-directional radio wave A, the characteristic line 22 shown by the dotted line represents the body surface displacement of the subject 3 calculated from the second-directional radio wave B, and the characteristic line 23 shown by the solid line represents the time changes of the difference in each body surface displacement. The characteristic represented by the characteristic line 23 showing the difference represents the vital signs of the subject 3. As the waveform of this characteristic line 23, the waveform that clearly shows the vital signs is used as the above-mentioned model waveform for comparison with each received waveform received by the receiving unit 13.

[0065] Next, in Figure 4The magnitude of the vital signs of the subject 3 extracted in S208 is compared with a specified threshold in S209. At this time, as the magnitude of the vital signs, the average value of the vital signs over a specified period is used. Next, in S210, it is determined whether the magnitude of the vital signs of the extracted subject 3 is equal to or greater than the specified threshold. When the magnitude of the vital signs of the extracted subject 3 is equal to or greater than the specified threshold and the determination result in S210 is "Yes", the process returns to S206, and the processes of S206 to S209 are repeated. Through this repeated process, the vital signs of the subject 3 are continuously extracted.

[0066] The specified threshold in S210 uses, for example, a predetermined value of the power ratio SNR (signal-to-noise power ratio) of the vital sign signal strength S to the noise power N obtained from the frequency change waveform of the vital sign signal strength obtained by performing a fast Fourier transform (FFT) on the vital signs represented by the characteristic line 23 in Figure 5 . If the value of this SNR is greater than the predetermined value, it is determined in S210 that the magnitude of the vital signs of the subject 3 exceeds the specified threshold.

[0067] In addition, when the vital sign detection device 1 is composed of an FMCW radar, a predetermined value of the SNR in the frequency (distance) range where the subject 3 is assumed to exist in the IF waveform obtained by applying the FFT to the IF (intermediate frequency) signal of the reflected signal received by the receiving unit 13, or a predetermined value of the signal strength can also be used as the specified threshold in S210. In the FMCW radar, if the FFT is applied to the IF signal, the reflected power corresponding to the distance can be seen, and a signal with a higher reflected power in the frequency (distance) range where the subject 3 is assumed to exist is determined as a vital sign. Therefore, if the value of the SNR or the signal strength in the frequency (distance) range where the subject 3 is assumed to exist in the IF waveform obtained by applying the FFT to the IF signal of the reflected signal received by the receiving unit 13 is greater than the predetermined value, it is determined in S210 that the magnitude of the vital signs of the subject 3 exceeds the specified threshold.

[0068] On the other hand, when the magnitude of the vital signs of the extracted subject 3 does not exceed the specified threshold and the determination result in S210 is "No", the process returns to S201, and the processes of S201 to S209 are repeated. Through this repeated process, a new first directivity for irradiating the new irradiation area where the vital signs of the subject 3 are likely to appear with the radio wave A and a new second directivity for irradiating the new irradiation area where the vital signs of the subject 3 are unlikely to appear with the radio wave B are determined, and each radio wave A and B is irradiated to each new irradiation area, and the vital signs of the subject 3 are continuously extracted again.

[0069] According to the vital sign detection device 1 and the vital sign detection method of such a first embodiment, the directivities of the radio waves A and B emitted from one irradiation unit 11 to the subject 3 are changed to a first directivity and a second directivity by the control unit 15 controlling the scanning unit 12, and the radio waves A and B are irradiated from the irradiation unit 11 to the irradiation area where the vital signs of the subject 3 are likely to appear and the irradiation area where the vital signs of the subject 3 are unlikely to appear. By using the vital sign extraction unit 16 to obtain the difference between the distance information from the vital sign detection device 1 to the irradiation site that irradiates electromagnetic waves to the subject 3 calculated based on the radio wave A with the first directivity reflected by the subject 3 and received by the receiving unit 13 and the distance information from the vital sign detection device 1 to the irradiation site that irradiates electromagnetic waves to the subject 3 calculated based on the radio wave B with the second directivity reflected by the subject 3 and received by the receiving unit 13, the noise included in the vital signs of the subject 3 is removed, and the vital signs of the subject 3 are accurately extracted.

[0070] In addition, even if the body shape and posture of the subject 3 change, the directivities of the radio waves A and B emitted from the irradiation unit 11 to the subject 3 are changed to the first directivity that irradiates the radio wave A to the irradiation area where the vital signs of the subject 3 are likely to appear and the second directivity that irradiates the radio wave B to the irradiation area where the vital signs of the subject 3 are unlikely to appear by the control unit 15 controlling the scanning unit 12. Therefore, even if the body shape and posture of the subject 3 change, the radio waves A and B emitted from the irradiation unit 11 are irradiated to the irradiation area where the vital signs of the subject 3 are likely to appear and the irradiation area where the vital signs of the subject 3 are unlikely to appear, and the vital sign extraction unit 16 removes the noise such as body movement and vibration included in the vital signs of the subject 3, and only the vital signs of the subject 3 are accurately extracted.

[0071] In addition, according to the vital sign detection device 1 and the vital sign detection method of the first embodiment, since the vital signs of the subject 3 are accurately extracted as described above by using one irradiation unit 11, the space occupied by the vital sign detection device 1 in its installation site can be suppressed, the width of the selection of the installation site of the vital sign detection device 1 becomes wider, and the degree of freedom in design is improved. In addition, the cost of the vital sign detection device 1 can also be suppressed.

[0072] As a result, according to the first embodiment, it is possible to provide a vital sign detection device 1 and a vital sign detection method that can remove the noise included in the vital signs of the subject 3 even if the body shape and posture of the subject 3 change, always accurately extract only the vital signs of the subject 3, and improve the degree of freedom in design and suppress the cost.

[0073] In addition, in the first embodiment, since the frequency bands of the first-directional radio wave A and the second-directional radio wave B are set to be the same, there is no need to emit radio waves of different frequency bands like conventional biological sensors. Therefore, the design of the vital sign detection device 1 and the vital sign detection method becomes easier. As a result, it is possible to contribute to accurately extracting the vital signs of the subject 3 at low cost. In addition, the frequency bands of the first-directional radio wave A and the second-directional radio wave B do not have to be the same frequency band and can also be set to different frequency bands.

[0074] Figure 6 FIG. 4 is a schematic side view showing the state in which the subject 3 is seated on the seat 2 in the vehicle when the vital sign detection device according to the second embodiment is applied. The vital sign detection device according to the second embodiment has the same structure as the vital sign detection device 1 according to the first embodiment described above, except that a reflector 31 is disposed inside the seat 2. The reflector 31 is made of a material such as metal that easily reflects radio waves, and reflects the second-directional radio wave B emitted from the irradiation unit 11 to the receiving unit 13.

[0075] It is considered that the calculation result of the body surface displacement of the subject 3 obtained from the second-directional radio wave B in which the vital signs of the subject 3 are difficult to appear is the same when the radio wave B irradiates the subject 3 and when it irradiates the reflector 31. Therefore, according to the vital sign detection device of the second embodiment, by controlling the scanning unit 12 by the control unit 15, the radio wave B emitted from the irradiation unit 11 is made to have a directivity that irradiates the reflector 31, so that it is possible to easily and reliably perform the control of changing the directivity of the radio wave emitted from the irradiation unit 11 to the subject 3 to the second directivity that irradiates the irradiation area where the vital signs of the subject 3 are difficult to appear. Therefore, in Figure 4 the processes of S201 to S204, there is no need to perform the process of determining the candidates for the second directivity, the control process of the directivity determination unit 14 can be simplified, and the noise included in the vital signs of the subject 3 can be easily and reliably removed by the vital sign extraction unit 16.

[0076] In addition, in the first embodiment and the second embodiment described above, the following situation has been described: when determining the first directivity and the second directivity of the electromagnetic wave, in Figure 3 S101, the electromagnetic wave is irradiated from the irradiation unit 11 to the subject 3, and when extracting the vital signs of the subject 3, in Figure 3In S103, electromagnetic waves are re-irradiated from the irradiation unit 11 to the subject 3 with the determined directivity. However, it may also be configured to irradiate the subject 3 only once with electromagnetic waves having multiple directivities, and the electromagnetic waves having multiple directivities reflected from the subject 3 are received by the receiving unit 13 through this irradiation. The first directivity and the second directivity of the electromagnetic waves are determined based on the received electromagnetic waves, and the vital signs of the subject 3 are extracted based on the electromagnetic waves of each determined directivity.

[0077] The vital sign detection device 1 according to the third embodiment of the present invention having such a structure includes an irradiation unit 11, a scanning unit 12, a receiving unit 13, and a vital sign extraction unit 16. The irradiation unit 11 emits electromagnetic waves to the subject 3, the scanning unit 12 scans the irradiation area of the electromagnetic waves irradiated to the subject 3 by changing the directivity of the electromagnetic waves emitted from the irradiation unit 11, the receiving unit 13 receives a plurality of electromagnetic waves with different directivities reflected from the subject 3, and the vital sign extraction unit 16 uses the distance information of the subject 3 calculated based on the electromagnetic wave with the strongest signal intensity representing the vital signs of the subject 3 among the plurality of electromagnetic waves received by the receiving unit 13 and the difference between the distance information of the subject 3 calculated based on the electromagnetic wave with the strongest signal intensity representing noise other than the vital signs of the subject 3, that is, body movement and vibration, to extract the vital signs of the subject 3.

[0078] In addition, the vital sign detection method having the above structure includes the following steps: an electromagnetic wave scanning step of scanning the irradiation area of the electromagnetic waves irradiated to the subject 3 by the scanning unit 12 by changing the directivity of the electromagnetic waves irradiated from the irradiation unit 11 to the subject 3; an electromagnetic wave receiving step of receiving a plurality of electromagnetic waves with different directivities scanned in the electromagnetic wave scanning step, reflected from the subject 3, and received by the receiving unit 13; a vital sign extraction step of using the difference between the distance information of the subject 3 calculated based on the electromagnetic wave with the strongest signal intensity representing the vital signs of the subject 3 among the plurality of electromagnetic waves received by the receiving unit 13 and the distance information of the subject 3 calculated based on the electromagnetic wave with the strongest signal intensity representing noise other than the vital signs of the subject 3, that is, body movement and vibration, to extract the vital signs of the subject 3; a comparison step of comparing the magnitude of the vital signs of the subject 3 extracted in the vital sign extraction step with a specified threshold; and a vital sign re-extraction step of repeatedly executing the above electromagnetic wave scanning step, electromagnetic wave receiving step, and vital sign extraction step when the comparison result in the comparison step is that the magnitude of the vital signs of the subject 3 extracted in the vital sign extraction step does not exceed the specified threshold.

[0079] According to the vital sign detection device 1 and the vital sign detection method of such a third embodiment, the directivity of the electromagnetic wave emitted from one irradiation unit 11 to the subject 3 is changed to a plurality of directivities, and the electromagnetic wave is irradiated from the irradiation unit 11. The electromagnetic wave irradiated from the irradiation unit 11 is received by the receiving unit 13 as an electromagnetic wave having a plurality of directivities. Moreover, in the vital sign extraction unit 16, by obtaining the difference between the distance information of the subject 3 calculated based on the electromagnetic wave with the strongest signal intensity representing the vital signs of the subject 3 among the plurality of electromagnetic waves received by the receiving unit 13 and the distance information of the subject 3 calculated based on the electromagnetic wave with the strongest signal intensity other than the vital signs of the subject 3, the noise included in the vital signs of the subject 3 is removed, and the vital signs of the subject 3 are accurately extracted.

[0080] In addition, even if the body shape and posture of the subject 3 change, by using the scanning unit 12 to change the directivity of the electromagnetic wave emitted from the irradiation unit 11 to the subject 3, electromagnetic waves with new multiple directivities are received by the receiving unit 13. Moreover, in the vital sign extraction unit 16, based on the new multiple electromagnetic waves received by the receiving unit 13, the difference between the distance information of the subject 3 calculated based on the electromagnetic wave with the strongest signal intensity representing the vital signs of the subject 3 and the distance information of the subject 3 calculated based on the electromagnetic wave with the strongest signal intensity other than the vital signs of the subject 3 is obtained, thereby removing the noise included in the vital signs of the subject 3 and accurately extracting the new vital signs of the subject 3. Therefore, even if the body shape and posture of the subject 3 change, the vital signs of the subject 3 can be accurately extracted.

[0081] In addition, in the vital sign detection device 1 and the vital sign detection method of this third embodiment, since one irradiation unit 11 is also used to accurately extract the vital signs of the subject 3 as described above, the space occupied by the vital sign detection device 1 in its installation location can be suppressed, the width of the selection of the installation location of the vital sign detection device 1 becomes wider, and the degree of freedom in design is improved. In addition, the cost of the vital sign detection device 1 can also be suppressed.

[0082] In addition, the vital sign detection device 1 of the third embodiment described above may also be configured to include a directivity determination unit 14 and a control unit 15. In the case of the vital sign detection device 1 of the fourth embodiment having this structure, the directivity determination unit 14 determines the first directivity of the electromagnetic wave with the strongest signal intensity representing the vital signs of the subject 3 and the second directivity of the electromagnetic wave with the strongest signal intensity other than the vital signs of the subject 3 among the multiple electromagnetic waves received by the receiving unit 13 based on the reception result of the electromagnetic wave in the receiving unit 13, and stores them in the storage unit. In addition, the control unit 15 controls the scanning of the electromagnetic wave when changing the directivity of the electromagnetic wave emitted from the irradiation unit 11 by the scanning unit 12. In addition, the vital sign extraction unit 16 reads out the first directivity and the second directivity of the electromagnetic wave stored in the storage unit, and extracts the vital signs of the subject 3 based on the difference between the distance information from the vital sign detection device 1 to the irradiation site where the electromagnetic wave is irradiated to the subject 3 calculated from the electromagnetic wave of the read first directivity and the distance information from the vital sign detection device 1 to the irradiation site where the electromagnetic wave is irradiated to the subject 3 calculated from the electromagnetic wave of the read second directivity.

[0083] Figure 7 It is a flowchart showing an outline of a vital sign detection method using the vital sign detection device 1 of the fourth embodiment described above.

[0084] In this vital sign detection method, first, in the electromagnetic wave scanning step of S301, through the control of the scanning unit 12 by the control unit 15, the irradiation area where the electromagnetic wave is irradiated to the subject 3 is scanned by changing the directivity of the electromagnetic wave irradiated from the irradiation unit 11 to the subject 3. Next, in the electromagnetic wave reception step of S302, a plurality of electromagnetic waves with different directivities that are scanned in the electromagnetic wave scanning step of S301, reflected by hitting the subject 3, and received by the receiving unit 13 are received. Next, in the directivity determination step of S303, through the directivity determination unit 14, the first directivity of the electromagnetic wave with the strongest signal intensity representing the vital signs of the subject 3 and the second directivity of the electromagnetic wave with the strongest signal intensity other than the vital signs of the subject 3 among the multiple electromagnetic waves received by the receiving unit 13 are determined based on the reception result of the electromagnetic wave in the receiving unit 13. The determined first directivity and second directivity of the electromagnetic wave are stored in the storage unit by the directivity determination unit 14.

[0085] Next, in the directional reading step of S304, the first directivity and the second directivity of the electromagnetic wave stored in the storage unit are read out by the vital sign extraction unit 16. Further, in the vital sign extraction step of S305, the vital sign extraction unit 16 extracts the vital signs of the subject 3 based on the difference between the distance information from the vital sign detection device 1 to the irradiation site that irradiates the subject 3 with the electromagnetic wave calculated from the read first-directivity electromagnetic wave and the distance information from the vital sign detection device 1 to the irradiation site that irradiates the subject 3 with the electromagnetic wave calculated from the read second-directivity electromagnetic wave. Next, in the comparison step of S306, the magnitude of the vital signs of the subject 3 extracted in the vital sign extraction step of S305 described above is compared with a predetermined threshold value. When the magnitude of the vital signs of the subject 3 is equal to or greater than the predetermined threshold value and the comparison result of S306 is "Yes", the process returns to the process of S305, and the process of S305 is repeated. On the other hand, when the magnitude of the vital signs of the subject 3 does not exceed the predetermined threshold value, the process returns to the process of S301, and the radio wave scanning step of S301, the electromagnetic wave reception step of S302, the directivity determination step of S303, the directional reading step of S304, and the vital sign extraction step of S305 are repeatedly executed to perform the vital sign re-extraction step.

[0086] According to the vital sign detection device 1 and the vital sign detection method of the fourth embodiment as described above, similar to the vital sign detection device 1 and the vital sign detection method of the third embodiment, by obtaining the difference between the distance information of the subject 3 calculated from the electromagnetic wave with the strongest signal intensity representing the vital signs of the subject 3 among the plurality of electromagnetic waves received by the receiving unit 13 and the distance information of the subject 3 calculated from the electromagnetic wave with the strongest signal intensity other than the vital signs of the subject 3, the noise included in the vital signs of the subject 3 is removed, and the vital signs of the subject 3 are accurately extracted. In addition, even when the body shape and posture of the subject 3 change, by the control of the scanning unit 12 by the control unit 15, the directivity of the electromagnetic wave emitted from the irradiation unit 11 to the subject 3 is changed, so that the electromagnetic waves with new multiple directivities are also received by the receiving unit 13, and the new vital signs of the subject 3 are accurately extracted. Therefore, even when the body shape and posture of the subject 3 change, the vital signs of the subject 3 can be accurately extracted. Further, in the vital sign detection device 1 and the vital sign detection method of the fourth embodiment, the vital signs of the subject 3 are accurately extracted by using one irradiation unit 11 as described above. Therefore, the space occupied by the vital sign detection device 1 in its installation location can be suppressed, the width of the selection of the installation location of the vital sign detection device 1 is widened, and the degree of freedom in design is improved. In addition, the cost of the vital sign detection device 1 can also be suppressed.

[0087] In addition, in the above-described third and fourth embodiments, the frequency bands of the first-directional radio wave A and the second-directional radio wave B are also set to be the same. Thus, it is not necessary to emit radio waves of different frequency bands as in conventional biological sensors. Therefore, the design of the vital sign detection device 1 and the vital sign detection method becomes easier. As a result, it is possible to contribute to accurately extracting the vital signs of the subject 3 at low cost.

[0088] In addition, in the above-described third and fourth embodiments, similarly to the vital sign detection device of the second embodiment, a reflector 31 may be configured to be disposed inside the seat 2. In the vital sign detection device having such a structure, by making the radio wave B emitted from the irradiation unit 11 have a directivity that irradiates the reflector 31, it is possible to easily and reliably remove the noise included in the vital signs of the subject 3 by the vital sign extraction unit 16.

[0089] In addition, in the above-described embodiments, the case where the vital sign detection device 1 is disposed on the seat 41 in the passenger compartment of an automobile as shown in (a) of Figure 8 has been described. However, the vital sign detection device 1 may be configured to be disposed on the dashboard 42, the rearview mirror 43, the ceiling 44 of the vehicle interior, the seat belt 45, the glove box 46, etc.

[0090] In the above-described embodiments, the case where the present invention is applied to a driver monitoring system of an automobile has been described. However, the vital sign detection devices of the embodiments may be provided on the seats in the driver's cabs of vehicles such as airplanes and trains, and applied to the driver monitoring systems of vehicles such as airplanes and trains. In addition, as in Figure 8 (b) shown in a hospital ward, by disposing the vital sign detection device of the present invention on the bed 51, the wall 52, the ceiling 53, the chair 54, the lighting 55, etc. in a medical facility, the vital signs of a patient or the like can be detected and applied to the nursing of a patient or the like.

[0091] Explanation of Reference Numerals

[0092] 1... Vital sign detection device; 2... Seat; 3... Subject; 11... Irradiation unit; 12... Scanning unit; 13... Receiving unit; 14... Directivity determination unit; 15... Control unit; 16... Vital sign extraction unit; 31... Reflector; A... First-directional radio wave; B... Second-directional radio wave.

Claims

1. A vital sign detection device, comprising: An irradiation unit that emits electromagnetic waves towards a subject; A scanning unit that scans the irradiation area of the electromagnetic waves irradiated on the subject by changing the directivity of the electromagnetic waves emitted from the irradiation unit; A receiving unit that receives a plurality of electromagnetic waves with different directivities that are reflected by the subject; and A vital sign extraction unit that uses the difference between the distance information of the subject calculated based on the electromagnetic wave with the strongest signal intensity representing the vital signs of the subject among the plurality of electromagnetic waves received by the receiving unit and the distance information of the subject calculated based on the electromagnetic wave with the strongest signal intensity other than the vital signs of the subject to extract the vital signs of the subject.

2. The vital sign detection device according to claim 1, wherein, Comprising: A directivity determination unit that determines the first directivity of the electromagnetic wave with the strongest signal intensity representing the vital signs of the subject and the second directivity of the electromagnetic wave with the strongest signal intensity other than the vital signs of the subject among the plurality of electromagnetic waves received by the receiving unit according to the reception result of the electromagnetic waves in the receiving unit, and stores them in a storage unit; and A control unit that controls the scanning of the electromagnetic waves when changing the directivity of the electromagnetic waves emitted from the irradiation unit for the scanning unit, The vital sign extraction unit reads out the first directivity and the second directivity of the electromagnetic waves stored in the storage unit, and based on the difference between the distance information from the vital sign detection device to the irradiation site that irradiates the subject with electromagnetic waves calculated according to the electromagnetic wave with the read first directivity and the distance information from the vital sign detection device to the irradiation site that irradiates the subject with electromagnetic waves calculated according to the electromagnetic wave with the read second directivity, extracts the vital signs of the subject.

3. The vital sign detection device according to claim 2, wherein The frequency bands of the electromagnetic wave with the first directivity and the electromagnetic wave with the second directivity are the same.

4. The vital sign detection device according to claim 2, wherein A reflector is provided to reflect the electromagnetic wave with the second directivity emitted from the irradiation unit to the receiving unit.

5. A vital sign detection device, comprising: An irradiation unit that emits electromagnetic waves towards a subject; A scanning unit that scans the irradiation area of the electromagnetic waves irradiated on the subject by changing the directivity of the electromagnetic waves emitted from the irradiation unit; A receiving unit that receives the electromagnetic waves reflected by the subject; A directivity determination unit that determines the first directivity of the electromagnetic waves that make the vital signs of the subject easily appear in the irradiation area where the electromagnetic waves irradiate the subject and the second directivity of the electromagnetic waves that make the vital signs of the subject difficult to appear in the irradiation area where the electromagnetic waves irradiate the subject according to the reception result of the electromagnetic waves in the receiving unit; A control unit that controls the scanning of the electromagnetic waves when the first directivity and the second directivity are determined by the directivity determination unit for the scanning unit, and controls to make the directivity of the electromagnetic waves irradiated on the subject be the first directivity or the second directivity determined by the directivity determination unit; and The vital sign extraction unit extracts the vital signs of the subject based on the difference between the distance information from the vital sign detection device to the irradiation site that irradiates the subject with electromagnetic waves calculated from the first-directional electromagnetic waves reflected by the subject and received by the receiving unit, and the distance information from the vital sign detection device to the irradiation site that irradiates the subject with electromagnetic waves calculated from the second-directional electromagnetic waves reflected by the subject and received by the receiving unit.

6. The vital sign detection device according to claim 5, wherein: The receiving unit includes a calculation unit, and the calculation unit calculates the difference between the distance information from the vital sign detection device to the irradiation site that irradiates the subject with electromagnetic waves calculated from the first-directional electromagnetic waves reflected by the subject and received by the receiving unit, and the distance information from the vital sign detection device to the irradiation site that irradiates the subject with electromagnetic waves calculated from the second-directional electromagnetic waves reflected by the subject and received by the receiving unit.

7. The vital sign detection device according to claim 5 or 6, wherein: The directivity determination unit has: A candidate determination unit that determines the irradiation directions of the electromagnetic waves that are candidates for the first directivity and the second directivity, and instructs the control unit to make the irradiation direction of the electromagnetic waves emitted from the irradiation unit be the determined irradiation direction; and A direction determination unit that determines the first directivity and the second directivity, and instructs the control unit to make the directivity of the electromagnetic waves emitted from the irradiation unit be the determined first directivity and second directivity.

8. The vital sign detection device according to claim 7, wherein: For each of the candidates, the candidate determination unit determines the irradiation range of the electromagnetic waves emitted from the irradiation unit to the subject and the size of the scanning angle for scanning the electromagnetic waves within the irradiation range, and instructs the control unit to emit the electromagnetic waves from the irradiation unit with the determined irradiation range and the size of the scanning angle.

9. The vital sign detection device according to claim 7, wherein: The direction determination unit compares a plurality of received waveforms of the electromagnetic waves that are irradiated in the irradiation direction of the candidate determined as the first directivity by the candidate determination unit, hit the subject, and are received by the receiving unit, with a model waveform of the electromagnetic waves having the first directivity prepared in advance, calculates the similarity between each of the received waveforms and the model waveform, and determines the first directivity.

10. The vital sign detection device according to claim 5 or 6, wherein: The frequency bands of the electromagnetic waves of the first directivity and the electromagnetic waves of the second directivity are the same.

11. The vital sign detection device according to claim 5 or 6, wherein: A reflector is provided to reflect the second-directional electromagnetic waves emitted from the irradiation unit to the receiving unit.

12. A vehicle, wherein: The vital sign detection device according to any one of claims 1 to 11 is provided on a seat.

13. A vital sign detection method, comprising: An electromagnetic wave scanning step of scanning, by a scanning unit, an irradiation area of the electromagnetic wave to a subject by changing a directivity of the electromagnetic wave irradiated from an irradiation unit to the subject; An electromagnetic wave receiving step of receiving a plurality of electromagnetic waves with different directivities that are scanned in the electromagnetic wave scanning step, hit the subject, are reflected, and are received by a receiving unit; A vital sign extraction step of extracting a vital sign of the subject by using a difference between distance information of the subject calculated based on the electromagnetic wave with the strongest signal intensity representing the vital sign of the subject among the plurality of electromagnetic waves received by the receiving unit and distance information of the subject calculated based on the electromagnetic wave with the strongest signal intensity other than the vital sign of the subject; A comparison step of comparing a magnitude of the vital sign of the subject extracted in the vital sign extraction step with a predetermined threshold; and A vital sign re-extraction step of repeatedly executing the electromagnetic wave scanning step, the electromagnetic wave receiving step, and the vital sign extraction step when a comparison result in the comparison step is that the magnitude of the vital sign of the subject extracted in the vital sign extraction step does not exceed the predetermined threshold.

14. A vital sign detection method, comprising: An electromagnetic wave scanning step of scanning, by a scanning unit, an irradiation area of the electromagnetic wave to a subject by changing a directivity of the electromagnetic wave irradiated from an irradiation unit to the subject; A directivity determination step of determining, by a directivity determination unit, a first directivity of the electromagnetic wave for irradiating an irradiation area where a vital sign of the subject is likely to appear and a second directivity of the electromagnetic wave for irradiating an irradiation area where a vital sign of the subject is unlikely to appear based on a reception result of the electromagnetic wave that is scanned in the electromagnetic wave scanning step, hits the subject, is reflected, and is received by the receiving unit; An electromagnetic wave irradiation step of emitting, from the irradiation unit, each of the electromagnetic waves having the first directivity and the second directivity determined in the directivity determination step to the subject, and irradiating the irradiation area where a vital sign of the subject is likely to appear and the irradiation area where a vital sign of the subject is unlikely to appear with the electromagnetic wave; A vital sign extraction step of extracting a vital sign of the subject based on a difference between distance information from a vital sign detection device to an irradiation site that irradiates the subject with the electromagnetic wave calculated based on the electromagnetic wave with the first directivity reflected by the subject and received by the receiving unit and distance information from the vital sign detection device to the irradiation site that irradiates the subject with the electromagnetic wave calculated based on the electromagnetic wave with the second directivity reflected by the subject and received by the receiving unit; A comparison step of comparing a magnitude of the vital sign of the subject extracted in the vital sign extraction step with a predetermined threshold; and Vital sign re-extraction step. In the case where the comparison result in the above comparison step is that the magnitude of the vital signs of the subject extracted in the above vital sign extraction step does not exceed the specified threshold, the above electromagnetic wave scanning step, the above directivity determination step, the above electromagnetic wave irradiation step, and the above vital sign extraction step are repeatedly executed.

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