Sensor system and vehicle equipped with the same

Abstract

Provided are: a sensor system which is capable of reducing power consumption without changing the detection accuracy of a prescribed displacement exhibited by a measurement target, even when using a plurality of first and second sensors; and a vehicle equipped with the same. This sensor system (1) is equipped with a first sensor (2), a second sensor (3) and a signal processing device (4). The first sensor (2) emits an electromagnetic wave at a measurement target (5), and detects a prescribed displacement which is exhibited by the measurement target (5) on the basis of a reflected wave. The second sensor (3) detects vibrations which occur in or are transmitted to the measurement target (5) and / or the first sensor (2), or detects a prescribed displacement exhibited by the measurement target (5). On the basis of the detected data, an operation sensor determination unit (4a) removes or attenuates noise vibrations which overlap the prescribed displacement, and selects an operation sensor which must be switched to the minimum operation level. A sensor power supply management unit (4b) provides a supply of power only to the sensor which was selected to function as the operation sensor.

Description

Technical Field

[0001] The present invention relates to a sensor system that emits electromagnetic waves and receives reflected waves returning from a measurement target, and a vehicle equipped with the same.

Background Art

[0002] Conventionally, as this type of sensor system, for example, there is one disclosed in Patent Document 1.

[0003] This sensor system includes a radio wave sensor, a vibration sensor, and a signal processing device. The radio wave sensor transmits radio waves within a detection area, receives radio waves reflected by an object, and outputs a radio wave sensor signal corresponding to the state of the object to the signal processing device. The vibration sensor detects vibrations of at least one of the radio wave sensor and the object, and outputs a vibration sensor signal corresponding to the detected vibration to the signal processing device. The signal processing device attenuates the vibration component detected by the vibration sensor signal from the radio wave sensor signal to generate a signal mainly including the components of the object.

[0004] In the same document, in order to improve the detection accuracy of the state of an object, it has been proposed to provide a plurality of radio wave sensors and vibration sensors respectively.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, the above-described conventional sensor system disclosed in Patent Document 1 attempts to improve the detection accuracy of the state of an object by obtaining a large amount of sensor information using a plurality of radio wave sensors and vibration sensors. For this reason, in the above-described conventional sensor system, the power consumption of the sensor system increases in proportion to the increase in the number of sensors.

Means for Solving the Problems

[0007] The present invention has been made to solve such problems, one or more first sensors that emit electromagnetic waves toward a measurement target, receive reflected waves that are reflected when the electromagnetic waves hit the measurement target, and detect a predetermined displacement exhibited by the measurement target; one or more second sensors that detect vibrations generated or transmitted to at least one of the measurement target or the first sensor, or the predetermined displacement; an operation sensor determination unit that determines an operation sensor that needs to operate minimally in order to remove or attenuate noise vibrations superimposed as noise on the predetermined displacement based on the predetermined displacement and the vibration; a sensor power management unit that supplies power only to the operation sensor to constitute a sensor system.

[0008] According to this configuration, an operation sensor that needs to operate minimally in order to remove or attenuate noise vibrations superimposed on a predetermined displacement exhibited by the measurement target is determined by the operation sensor determination unit from among one or more first sensors and one or more second sensors. The sensor power management unit supplies power only to the operation sensor determined by the operation sensor determination unit.

[0009] Therefore, even if a plurality of first sensors and second sensors are provided in the sensor system to improve the detection accuracy of a predetermined displacement exhibited by the measurement target, the power supply is provided only to the sensors that need to operate at least minimally to remove or attenuate the noise vibration superimposed on the predetermined displacement, rather than to all the sensors. For this reason, even if a plurality of first sensors and second sensors are used to improve the detection accuracy of the predetermined displacement exhibited by the measurement target, the power consumption of the sensor system can be reduced without changing the detection accuracy.

[0010] Also, the present invention one or more first sensors that emit electromagnetic waves toward the measurement target and receive reflected waves that are reflected by the measurement target to detect a predetermined displacement exhibited by the measurement target, one or more second sensors that detect vibrations generated or transmitted to at least one of the measurement target or the first sensor, or the predetermined displacement, a noise vibration removal unit that performs an operation to remove or attenuate the noise vibration superimposed as noise on the predetermined displacement from the predetermined displacement based on the predetermined displacement and the vibration, for a plurality of combinations of the first sensor and the second sensor, or a plurality of combinations of the first sensor, or a plurality of combinations of the second sensor; an operation sensor determination unit that determines, as an operation sensor, any one of the combinations that leads to the value closest to the true value of the predetermined displacement among the plurality of predetermined displacements obtained by removing or attenuating the noise vibration, which is necessary to operate at least minimally to remove or attenuate the noise vibration; a sensor power management unit that supplies power only to the operation sensor and constitutes a sensor system including the same.

[0011] According to this configuration, based on a predetermined displacement and vibration detected by the first sensor or the second sensor, an operation for removing or attenuating noise vibration superimposed as noise on the predetermined displacement from the predetermined displacement is performed by the noise vibration removal unit for various combinations of sensors. The motion sensor determination unit determines, among a plurality of predetermined displacements obtained by removing the noise vibration by the noise vibration removal unit, any combination that leads to the value closest to the true value of the predetermined displacement as a motion sensor that needs to be operated at least minimally to remove or attenuate the noise vibration superimposed on the predetermined displacement. The sensor power management unit supplies power only to the combination of sensors determined as the motion sensor by the motion sensor determination unit.

[0012] Therefore, even if a plurality of the first sensors and the second sensors are provided in the sensor system to improve the detection accuracy of the predetermined displacement exhibited by the measurement object, power is supplied not to all the sensors but only to the sensors that need to be operated at least minimally to remove or attenuate the noise vibration superimposed on the predetermined displacement. For this reason, even if a plurality of the first sensors and the second sensors are used to improve the detection accuracy of the predetermined displacement exhibited by the measurement object, the power consumption of the sensor system can be reduced without changing the detection accuracy.

[0013] Also, the present invention constitutes a vehicle equipped with the sensor system described above.

[0014] According to this configuration, it is possible to provide a vehicle equipped with a sensor system capable of reducing power consumption without changing the detection accuracy of a predetermined displacement.

Effects of the Invention

[0015] According to the present invention, even if a plurality of the first sensors and the second sensors are used to improve the detection accuracy of the predetermined displacement exhibited by the measurement object, it is possible to provide a sensor system capable of reducing power consumption without changing the detection accuracy, and a vehicle equipped with the same.

Brief Description of the Drawings

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Embodiments for Carrying Out the Invention

[0017] Next, embodiments for implementing the sensor system of the present invention and a vehicle equipped with the same will be described.

[0018] FIG. 1 is a block diagram showing the schematic configuration of a sensor system 1 according to the first embodiment of the present invention. The sensor system 1 is configured to include one or more first sensors 2, one or more second sensors 3, and a signal processing device 4.

[0019] The first sensor 2 is, for example, a radio wave sensor. The radio wave sensor emits electromagnetic waves toward the measurement target 5 and receives the reflected waves (incident reflected waves) that are reflected when the electromagnetic waves hit the measurement target 5. The radio wave sensor detects a predetermined displacement presented by the measurement target 5, such as the body surface displacement of a human body, from this reflected wave, and outputs the detected predetermined displacement data to the signal processing device 4. The radio wave sensor is constituted by, for example, a Doppler radar, an FMCW (Frequency Modulated Continuous Wave radar) radar, a pulse radar, or the like. In the present embodiment, the electromagnetic waves emitted by the radio wave sensor are described as radio waves, but electromagnetic waves widely include sound waves, light waves, and the like. Further, the first sensor 2 is, for example, a pressure sensor. Further, the first sensor 2 is, for example, a displacement sensor. Examples of the displacement sensor include a camera and an infrared laser.

[0020] The second sensor 3 is, for example, a vibration sensor or a displacement sensor. The vibration sensor is constituted by, for example, a 6-axis inertial sensor, a vibration sensor such as a 3-axis acceleration sensor, or the like. The displacement sensor is constituted by a displacement sensor such as a pressure sensor. Examples of the displacement sensor include a camera and an infrared laser. When the second sensor 3 is a vibration sensor, the second sensor 3 detects vibrations generated in or transmitted to at least one of the measurement target 5 or the first sensor (radio wave sensor) 2. Further, when the second sensor 3 is a displacement sensor, the second sensor 3 detects a predetermined displacement presented by the measurement target 5, such as the body surface displacement of a human body from, for example, the pressure received by the pressure sensor from the human body. In this case, the pressure sensor functions as a vital sensor for detecting the vital signs of a human body. The second sensor 3 outputs the detected vibration data or displacement data such as body surface displacement to the signal processing device 4.

[0021] The signal processing device 4 includes an operation sensor determination unit 4a and a sensor power management unit 4b. The operation sensor determination unit 4a determines an operation sensor that needs to be operated at least minimally in order to remove or attenuate noise vibrations superimposed as noise on a predetermined displacement exhibited by the measurement target 5. Specifically, it determines any one of the first sensors 2 or the second sensors 3, or a plurality of first sensors 2, or a plurality of second sensors 3, or a combination of the first sensor 2 and the second sensor 3, or a plurality of combinations of the first sensor 2 and the second sensor 3. This determination is made based on a predetermined displacement detected by the first sensor 2 and vibrations or a predetermined displacement detected by the second sensor 3. Note that, in the following description, the type of operation sensor determined by the operation sensor determination unit 4a is an example, and any of the above types may be determined as the operation sensor.

[0022] Each of the predetermined displacement data detected by the first sensor 2 and the vibration data or displacement data detected by the second sensor 3 includes either or both of the predetermined displacement data exhibited by the measurement target 5 and the noise vibration component data superimposed on the predetermined displacement data.

[0023] When no noise vibration is detected in either the first sensor 2 or the second sensor 3, for example, when the sensor system 1 is used in a driver monitoring system (DMS) and the vehicle is in an idling state or is an electric vehicle and no noise vibration is detected, the operation sensor determination unit 4a determines only any one of the first sensors 2 or the second sensors 3 that detects a predetermined displacement as the operation sensor.

[0024] Further, the motion sensor determination unit 4a determines the sensor to be operated according to the vibration removal method of a noise vibration removal unit provided in the subsequent stage of the signal processing device 4 as described later. As an example of the vibration removal method, there is a removal method in which a noise vibration removal unit provided in the subsequent stage subtracts the detection data of another sensor that detects noise vibration from the detection data of a sensor that detects both a predetermined displacement and noise vibration. When the vibration removal method of the noise vibration removal unit is such a subtraction removal method that removes or attenuates noise vibration, and the total number of the first sensor 2 and the second sensor 3 is three or more, the motion sensor determination unit 4a determines the motion sensor as follows. That is, the motion sensor determination unit 4a determines a combination of any one of the first sensor 2 or the second sensor 3 that detects a predetermined displacement and noise vibration and any one of the other first sensor 2 or the second sensor 3 that detects noise vibration as the motion sensor.

[0025] Further, as an example of the vibration removal method, a removal method in which a noise vibration removal unit separates noise vibration from a predetermined displacement using a blind source separation technique may be used. When the vibration removal method is a blind source separation technique and the total number of the first sensor 2 and the second sensor 3 is three or more, the motion sensor determination unit 4a determines the motion sensor as follows. That is, the motion sensor determination unit 4a determines a combination of any one of the first sensor 2 or the second sensor 3 that detects both a predetermined displacement and noise vibration and any one of the other first sensor 2 or the second sensor 3 that detects both a predetermined displacement and noise vibration as the motion sensor.

[0026] The sensor power management unit 4b supplies power only to the first sensor 2 or the second sensor 3 determined as the motion sensor by the motion sensor determination unit 4a, or a combination thereof. Therefore, power supply is not performed for the remaining sensors that are not determined as the motion sensor. For this power supply control, the sensor power management unit 4b may directly control the power supply to be turned on or off for the first sensor 2 or the second sensor 3, or a combination thereof, or may output an instruction to turn on or off the power supply to each of these sensors.

[0027] Figure 2 is a flowchart showing the flow of power control processing performed on each sensor in the sensor system 1 according to the first embodiment of the present invention. Each step S101 to S106 performed in this power control processing is performed by a CPU (Central Processing Unit) provided in the signal processing device 4 according to a computer program stored in a memory provided in the signal processing device 4.

[0028] First, a detection data acquisition step S101 for acquiring data detected by each sensor is performed.

[0029] That is, in the first sensor 2, from the reflected wave obtained by the radio wave emitted from the radio wave sensor toward the measurement target 5 hitting the measurement target 5 and reflecting, predetermined displacement data presented by the measurement target 5, for example, body surface displacement data of a human body, etc. is acquired. This displacement data may include a noise vibration component generated by vibration generated or transmitted to at least one of the measurement target 5 or the first sensor 2. In the second sensor 3, vibration data generated or transmitted to at least one of the measurement target 5 or the first sensor 2, or predetermined displacement data presented by the measurement target 5, for example, body surface displacement data of a human body, etc. is acquired. Each acquired detection data is output from the first sensor 2 and the second sensor 3 to the motion sensor determination unit 4a.

[0030] Next, a data type discrimination step S102 for discriminating the type of data acquired by each sensor is performed by the motion sensor determination unit 4a.

[0031] That is, the motion sensor determination unit 4a designates as the main sensor one of the first sensor 2 or the second sensor 3 that detects displacement data closest to the true value of the predetermined displacement data among the sensors that detect the predetermined displacement data presented by the measurement target 5. Then, in that main sensor, the predetermined displacement data detected for the measurement target 5 in the stationary state is stored in advance in the memory as reference data. Alternatively, data predetermined as the predetermined displacement data obtained for the measurement target 5 in the stationary state is stored in advance in the memory as reference data. The motion sensor determination unit 4a determines as the sensor for detecting a predetermined displacement such as body surface displacement a sensor that detects data having a high correlation with the reference data stored in the memory or having a similar statistic such as kurtosis in a specific frequency band in which the predetermined displacement data is obtained. For example, when the predetermined displacement data is body surface displacement data of a human body, it is in the frequency band of 0 to 10 Hz including respiration and heartbeat, or in the frequency band of 1 to 10 Hz including only heartbeat.

[0032] Further, when vibration data other than the predetermined displacement data in a specific frequency band is defined as noise vibration data in the vibration state of the main sensor, a sensor that detects data having a high correlation with the noise vibration data or having a similar statistic such as kurtosis in the specific frequency band in another sensor other than the main sensor is determined as the sensor for detecting noise vibration superimposed on the predetermined displacement data.

[0033] Next, a noise vibration detection sensor determination step S103 for determining whether any of the sensors has acquired noise vibration data is performed by the motion sensor determination unit 4a. That is, in the data type determination step S102, the motion sensor determination unit 4a determines whether there is a sensor for detecting noise vibration.

[0034] If the determination result in the noise vibration detection sensor determination step S103 is No and there is no sensor that has acquired noise vibration data, in the motion sensor first determination step S104, the main sensor is determined by the motion sensor determination unit 4a as a motion sensor that needs to operate at least to remove or attenuate the noise vibration superimposed on the predetermined displacement.

[0035] Also, if the determination result in the noise vibration detection sensor determination step S103 is Yes and there is a sensor that has acquired noise vibration data, in the motion sensor second determination step S105, the combination of sensors according to the subsequent noise vibration removal method is determined by the motion sensor determination unit 4a as a motion sensor.

[0036] That is, when the subsequent noise vibration removal method is the above-described subtraction removal method, the combination of any one of the first sensor 2 or the second sensor 3 that detects the predetermined displacement and the noise vibration and any one of the other first sensor 2 or the second sensor 3 that detects the noise vibration is determined as a motion sensor by the motion sensor determination unit 4a. Also, when the subsequent noise vibration removal method is the above-described blind sound source separation method, the combination of any one of the first sensor 2 or the second sensor 3 that detects both the predetermined displacement and the noise vibration and any one of the other first sensor 2 or the second sensor 3 that detects both the predetermined displacement and the noise vibration is determined as a motion sensor by the motion sensor determination unit 4a.

[0037] Next, the sensor power supply setting step S106 in which the power supply of each sensor is turned ON or OFF according to the determination result of the motion sensor determination unit 4a is performed by the sensor power supply management unit 4b.

[0038] That is, when the main sensor is determined by the motion sensor determination unit 4a as a motion sensor in the motion sensor first determination step S104, the power supply of the main sensor is turned on by the sensor power management unit 4b, and the power supplies of the remaining respective sensors are turned off by the sensor power management unit 4b. Further, in the motion sensor second determination step S105, the power supplies of any combination of the sensors determined as motion sensors according to the subsequent noise vibration removal method are turned on by the sensor power management unit 4b, and the power supplies of the remaining respective sensors are turned off by the sensor power management unit 4b.

[0039] According to the sensor system 1 according to such a first embodiment, among one or more first sensors 2 and one or more second sensors 3, the motion sensor that needs to be operated at least to remove or attenuate the noise vibration superimposed on the predetermined displacement presented by the measurement object 5 is determined by the motion sensor determination unit 4a. The sensor power management unit 4b supplies power only to the first sensor 2 or the second sensor 3 determined as a motion sensor by the motion sensor determination unit 4a, or a combination thereof. Therefore, in detecting the predetermined displacement presented by the measurement object 5, the operation of the sensor that has no influence or has a minor influence on the detection result of the predetermined displacement is stopped.

[0040] Therefore, even if a plurality of the first sensors 2 and the second sensors 3 are provided in the sensor system 1 in order to improve the detection accuracy of the predetermined displacement presented by the measurement object 5, the power is supplied not to all the sensors but only to the sensors that need to be operated at least to remove or attenuate the noise vibration superimposed on the predetermined displacement. For this reason, even if a plurality of the first sensors 2 and the second sensors 3 are used to improve the detection accuracy of the predetermined displacement presented by the measurement object 5, for example, the body surface displacement of the human body, the power consumption of the sensor system 1 can be reduced without changing the detection accuracy.

[0041] Also, according to the sensor system 1 according to the first embodiment, when the determination result in the noise vibration detection sensor determination step S103 in FIG. 2 is No and no noise vibration is detected in either the first sensor 2 or the second sensor 3, only the one of the first sensor 2 or the second sensor 3 that detects a predetermined displacement and is regarded as the main sensor is determined as the motion sensor by the motion sensor first determination unit 4a in the motion sensor first determination step S104. Then, power is supplied to only that one motion sensor by the sensor power management unit 4b. Therefore, the power consumption of the sensor system 1 can be further reduced without changing the detection accuracy of the predetermined displacement exhibited by the measurement object 5.

[0042] Also, according to the sensor system 1 according to the first embodiment, a predetermined displacement exhibited by the measurement object 5 can be detected by the sensor system 1 with low power consumption without changing the detection accuracy by any combination of one of the first sensor 2 and the second sensor 3, the total number of which is three or more, and determined as the motion sensor according to the subtraction removal method in the motion sensor second determination step S105. In this case, data of the noise vibration detected by any one of the other sensors is subtracted from the combined data of the predetermined displacement and the noise vibration detected by any one of the sensors determined as the motion sensor by the noise vibration removal unit in the subsequent stage, so that the noise vibration is removed or attenuated from the predetermined displacement exhibited by the measurement object 5.

[0043] Further, according to the sensor system 1 according to the first embodiment, any one of the first sensors 2 and the second sensors 3 with a total number of three or more, which is determined as a motion sensor according to the blind source separation method in the motion sensor second determination step S105, and any other sensor, the predetermined displacement exhibited by the measurement object 5 can be detected by the sensor system 1 with low power consumption without changing the detection accuracy. In this case, the blind source separation method is applied to the composite data of the predetermined displacement and the noise vibration detected by any one of the sensors determined as the motion sensor and the composite data of the predetermined displacement and the noise vibration detected by any other one of the sensors by the subsequent noise vibration removal unit. By applying this method, the noise vibration is removed or attenuated from the predetermined displacement exhibited by the measurement object 5 by separating the predetermined displacement from the difference in the strength of the noise vibration components superimposed on each sensor.

[0044] FIG. 3 is a perspective view showing the interior of a vehicle 11 equipped with such a sensor system 1 as a driver monitoring system.

[0045] When the sensor system 1 is provided in the vehicle 11 in this way, the first sensor 2 is installed on the seat back 11a, the seat portion 11b, the dashboard 11c, the ceiling 11d in the vehicle interior, etc., and the human body sitting on the seat is the measurement object 5, and radio waves are irradiated (emitted) to the human body. In this case, the body surface displacement of the human body is detected as the predetermined displacement of the measurement object 5 by the first sensor 2. Further, the second sensor 3 is installed on the seat back 11a, the seat portion 11b, the floor 11e in the vehicle interior, etc. When the second sensor 3 is installed on the seat back 11a or the seat portion 11b, when the second sensor 3 is a vibration sensor, the body movement of the human body is detected as vibration. When the second sensor 3 is a pressure sensor, the body surface displacement of the human body is detected as the predetermined displacement of the measurement object 5 from the pressure received by the pressure sensor from the human body. When the second sensor 3 is installed on the floor 11e in the vehicle interior, the vibration of the vehicle is detected as noise vibration superimposed on the body surface displacement of the human body.

[0046] According to this configuration, it is possible to provide a vehicle 11 equipped with a sensor system 1 that can reduce power consumption without changing the detection accuracy of a predetermined displacement such as a body surface displacement.

[0047] In addition, a radio wave sensor, a vibration or vital sensor, and a CPU provided in a wearable device such as a smartwatch or a smartphone can also be used to configure the sensor system 1. In this case, the radio wave sensor, the vibration sensor or vital sensor, and the CPU provided in the wearable device or smartphone function as the first sensor 2, the second sensor 3, and the signal processing device 4 shown in FIG. 1. Further, the program of the flowchart shown in FIG. 2 is downloaded from, for example, the Internet network as an application and installed in the wearable device or smartphone.

[0048] FIG. 4(a) is a block diagram showing a schematic configuration of a sensor system 21 according to a second embodiment of the present invention. The sensor system 21 is different from the sensor system 1 according to the first embodiment in that it includes a signal processing device 6 instead of the signal processing device 4 of the sensor system 1 according to the first embodiment, and other points are the same as those of the sensor system 1 according to the first embodiment.

[0049] The signal processing device 6 includes a noise vibration removal unit 6a, an operation sensor determination unit 6b, and a sensor power management unit 6c.

[0050] The noise vibration removal unit 6a performs an operation of removing or attenuating noise vibration superimposed as noise on a predetermined displacement based on the predetermined displacement and vibration exhibited by the measurement target 5 detected by the first sensor 2 or the second sensor 3. This operation is performed for a plurality of combinations of the first sensor 2 and the second sensor 3, or a plurality of combinations of the first sensor 2, or a plurality of combinations of the second sensor 3.

[0051] The motion sensor determination unit 6b determines, as a motion sensor that needs to be operated at least minimally to remove or attenuate the noise vibration superimposed on the predetermined displacement, any combination of sensors that leads to a value closest to the true value of the predetermined displacement among the plurality of predetermined displacements obtained by removing the noise vibration by the noise vibration removal unit 6a.

[0052] The sensor power management unit 6c supplies power only to the combination of sensors determined as motion sensors by the motion sensor determination unit 6b. Therefore, power supply is not performed for the remaining sensors that are not determined as motion sensors. The control of power supply by this sensor power management unit 6c may be such that, similar to the sensor power management unit 4b of the sensor system 1 in the first embodiment, the sensor power management unit 6c directly controls the power supply to each sensor to be turned on or off, or alternatively, it may output an instruction to turn on or off the power supply to each sensor.

[0053] The noise vibration removal unit 6a may use blind source separation techniques such as independent component analysis (ICA) and independent vector analysis (IVA) for vibration removal. By this technique, in the combination of sensors determined as motion sensors, it is possible to separate the noise vibration data from the predetermined displacement data such as body surface displacement. At this time, the dimension of the predetermined displacement data is m in the SI unit system, and the dimension of the noise vibration data is m / s in the SI unit system. 2 Therefore, the arithmetic processing in the noise vibration removal unit 6a is to perform independent component analysis or independent vector analysis after integrating the noise vibration data twice.

[0054] Further, the noise vibration removal unit 6a may use an adaptive filter using an algorithm such as LMS (Least Mean Square) for vibration removal. With this adaptive filter, noise vibration data input from any of the other sensors can be separated from predetermined displacement data such as body surface displacement input from any of the sensors determined as motion sensors. FIG. 4(b) is a block diagram showing the circuit configuration of the noise vibration removal unit 6a configured using such an adaptive filter 6a1.

[0055] Noise superimposed on predetermined displacement data such as body surface displacement propagates and superimposes over a distance from its source, and thus is affected by the transmission characteristics during that period. Therefore, the noise vibration removal unit 6a takes the difference between the predetermined displacement data and the noise vibration data with a subtractor 6a2, and feeds back the difference from the output of the subtractor 6a2 to the adaptive filter 6a1. Then, the magnitude of the transfer coefficient W1 of the adaptive filter 6a1 is adjusted to separate the noise vibration data from the predetermined displacement data and extract the body surface displacement and the like.

[0056] Also, the noise vibration removal unit 6a may use techniques of machine learning methods such as Demucs, Sepformer, Conv-TasNet used for voice separation, or their variants, for vibration removal. With these techniques, noise vibration data can be separated from predetermined displacement data such as body surface displacement in a combination of sensors determined as motion sensors.

[0057] FIG. 5 is a flowchart showing the flow of power control processing performed on each sensor in the sensor system 21 according to the second embodiment of the present invention. Each step S201 to S204 performed in this power control processing is also performed by the CPU provided in the signal processing device 6 according to a computer program stored in the memory provided in the signal processing device 6.

[0058] First, a detection data acquisition step S201 is performed to acquire data detected by each sensor.

[0059] That is, also in this detection data acquisition step S201, similar to the detection data acquisition step S101 in FIG. 2, in the first sensor 2, from the reflected wave obtained by the radio wave emitted from the radio wave sensor toward the measurement target 5 hitting the measurement target 5 and reflecting, predetermined displacement data presented by the measurement target 5, for example, body surface displacement data of a human body, etc. is acquired. In the second sensor 3, vibration data generated or transmitted to at least one of the measurement target 5 or the first sensor 2, or predetermined displacement data presented by the measurement target 5, for example, body surface displacement data of a human body, etc. is acquired.

[0060] Next, a noise vibration removal step S202 is performed by the noise vibration removal unit 6a to remove noise vibration from the predetermined displacement data by any of the above vibration removal methods. This process is performed for various combinations of a plurality of combinations of the first sensor 2 and the second sensor 3, or a plurality of combinations of the first sensor 2, or a plurality of combinations of the second sensor 3.

[0061] Next, an operation sensor determination step S203 is performed by the operation sensor determination unit 6b to determine one combination of sensors that detects a predetermined displacement that has the most noise vibration removed or attenuated and is closest to the true value of the predetermined displacement among the plurality of predetermined displacements from which the noise vibration has been removed or attenuated in the noise vibration removal step S202. This process is performed as follows.

[0062] That is, the motion sensor determination unit 6b first designates as the main sensor one of the first sensor 2 or the second sensor 3 that detects displacement data closest to the true value of the predetermined displacement data among the displacement data presented by the measurement target 5. Then, in that main sensor, the predetermined displacement data detected for the measurement target 5 in the stationary state is stored in advance in the memory as reference data. Alternatively, data predetermined as the predetermined displacement data obtained for the measurement target 5 in the stationary state is stored in advance in the memory as reference data. The motion sensor determination unit 6b determines, in a specific frequency band in which predetermined displacement data is obtained, for example, in the frequency band of 0 to 10 Hz including respiration and heartbeat when the predetermined displacement data is body surface displacement data of a human body, or in the frequency band of 1 to 10 Hz including only heartbeat, one combination of sensors that detects predetermined displacement data having the highest correlation with the reference data stored in the memory or having the closest statistic such as kurtosis, as the combination of sensors that detects the predetermined displacement closest to the true value of the predetermined displacement. Then, that combination of sensors is discriminated as the motion sensor that needs to be operated at least minimally to remove or attenuate the noise vibration superimposed on the predetermined displacement.

[0063] Next, a sensor power supply setting step S204 in which the power supplies of the respective sensors are turned ON or OFF according to the determination result of the motion sensor determination unit 6b is performed by the sensor power supply management unit 6c. That is, only the power supplies of one combination of sensors determined as motion sensors by the motion sensor determination unit 6b are turned ON by the sensor power supply management unit 6c, and the power supplies of the remaining respective sensors are turned OFF by the sensor power supply management unit 6c.

[0064] According to the sensor system 21 according to such a second embodiment, based on a predetermined displacement and vibration detected by any combination of sensors, an operation is performed to remove or attenuate noise vibration superimposed on the predetermined displacement exhibited by the measurement target 5 from the predetermined displacement. This operation is performed by the noise vibration removal unit 6a for various combinations of sensors in the noise vibration removal step S202. In the operation sensor determination step S203, the operation sensor determination unit 6b determines, as the operation sensor, any combination that leads to a value closest to the true value of the predetermined displacement among the plurality of predetermined displacements obtained by removing the noise vibration by the noise vibration removal unit 6a. The operation sensor is an operation sensor that needs to operate at least minimally to remove or attenuate the noise vibration superimposed on the predetermined displacement. The sensor power management unit 6c supplies power only to the combination of sensors determined as the operation sensor by the operation sensor determination unit 6b in the sensor power setting step S204.

[0065] Therefore, even if the sensor system 21 is configured to include a plurality of first sensors 2 and second sensors 3 in order to improve the detection accuracy of the predetermined displacement exhibited by the measurement target 5, power is supplied not to all the sensors but only to the sensors that need to operate at least minimally to remove or attenuate the noise vibration superimposed on the predetermined displacement. For this reason, even if a plurality of first sensors 2 and second sensors 3 are used to improve the detection accuracy of the predetermined displacement exhibited by the measurement target 5, the power consumption of the sensor system 21 can be reduced without changing the detection accuracy.

[0066] Also, the sensor system 21 according to the second embodiment can also be applied to a driver monitoring system by appropriately arranging the first sensor 2 and the second sensor 3 in the passenger compartment of the vehicle 11 as described with reference to FIG. 3. In this case, it is possible to provide a vehicle 11 equipped with the sensor system 21 that can reduce power consumption without changing the detection accuracy of a predetermined displacement such as body surface displacement.

[0067] FIG. 6 is a block diagram showing a schematic configuration of a sensor system 1A according to a third embodiment of the present invention. The sensor system 1A is configured to include a noise vibration removal unit 4c and a vital sign detection unit 4d in a signal processing device 4, and is different from the sensor system 1 according to the first embodiment in that the measurement target 5 is a human body, and other points are the same as those of the sensor system 1 according to the first embodiment.

[0068] The noise vibration removal unit 4c performs an operation to remove or attenuate the noise vibration detected by a combination of sensors determined as motion sensors by the motion sensor determination unit 4a from the body surface displacement detected as a predetermined displacement by the combination. This operation is performed for the combination of sensors determined as motion sensors by the motion sensor determination unit 4a in the motion sensor second determination step S105 when the determination result in the noise vibration detection sensor determination step S103 in FIG. 2 is Yes and there is a sensor that has acquired noise vibration data.

[0069] The vital sign detection unit 4d detects the vital signs of the human body from the body surface displacement from which the noise vibration has been removed or attenuated by the noise vibration removal unit 4c. The vital signs include the heart rate, heart rate variation, respiratory rate, and depth of respiration of the human body, which is the measurement target 5.

[0070] Further, when the determination result in the noise vibration detection sensor determination step S103 in FIG. 2 is No, there is no sensor that has acquired noise vibration data, and in the motion sensor first determination step S104, when the main sensor is determined as a motion sensor, the vital sign detection unit 4d detects the vital signs of the human body from the body surface displacement data of the human body detected as a predetermined displacement by the main sensor. In this case, the noise vibration removal unit 4c is not used.

[0071] According to such a sensor system 1A according to the third embodiment, noise vibration detected by the combination of sensors determined in step S105 as motion sensors is removed or attenuated from the body surface displacement detected by the combination by the noise vibration removal unit 4c, and the vital sign detection unit 4d detects the vital signs of the human body. Alternatively, the vital sign detection unit 4d detects the vital signs of the human body from the body surface displacement data in which the noise vibration detected by the main sensor determined as the motion sensor in step S104 has been removed or attenuated, without passing through the noise vibration removal unit 4c. Therefore, the vital signs of the human body can be detected by the sensor system 1A with low power consumption without degrading the detection accuracy of the vital signs of the human body.

[0072] Also, as described with reference to FIG. 3, the sensor system 1A according to the third embodiment can also be applied to a driver monitoring system by appropriately arranging the first sensor 2 and the second sensor 3 in the passenger compartment of the vehicle 11. In this case, it is possible to provide a vehicle 11 equipped with a sensor system 1A that can reduce power consumption without degrading the estimation performance of the vital signs of the human body.

[0073] FIG. 7 is a block diagram showing a schematic configuration of a sensor system 21A according to a fourth embodiment of the present invention. The sensor system 21A is configured to include a vital sign detection unit 6d in a signal processing device 6, and is different from the sensor system 21 according to the second embodiment in that the measurement target 5 is a human body, and other points are the same as those of the sensor system 21 according to the second embodiment.

[0074] The vital sign detection unit 6d detects the vital signs of the human body from the body surface displacements calculated by the combination of sensors determined as motion sensors by the motion sensor determination unit 6b among the plurality of body surface displacements from which the noise vibrations have been removed or attenuated by the noise vibration removal unit 6a. According to such a sensor system 21A according to the fourth embodiment, the vital signs of the human body can be detected by the sensor system 21A with low power consumption without degrading the detection accuracy of the vital signs of the human body.

[0075] Also, the sensor system 21A according to the fourth embodiment can also be applied to the driver monitoring system by appropriately arranging the first sensor 2 and the second sensor 3 in the passenger compartment of the vehicle 11 as described with reference to FIG. 3. Also in this case, it is possible to provide a vehicle 11 equipped with a sensor system 21A that can reduce power consumption without degrading the estimation performance of the vital signs of the human body.

[0076] FIG. 8 is a block diagram showing a schematic configuration of a sensor system 21B according to the fifth embodiment of the present invention. In the sensor system 21B, the second sensor 3 in the sensor system 21 according to the second embodiment is constituted by a vibration sensor or a vital sensor 3a built in a wearable device such as a smartwatch or a smartphone 7, and the difference from the sensor system 21 according to the second embodiment is that the measurement target 5 is the human body. Other points are the same as those of the sensor system 21 according to the second embodiment. The vital sensor 3a built in the wearable device or the smartphone 7 is a sensor capable of acquiring vital signs such as a PPG sensor (optical heart rate sensor) or an ECG sensor (electrocardiogram sensor).

[0077] The wearable device or smartphone 7 may be a portable device having a communication function with a vibration sensor or a vital sensor 3a, not limited thereto. In this configuration, the communication between the vibration sensor or vital sensor 3a and the signal processing device 6 is performed by wireless means such as Bluetooth (registered trademark) or by wire. Further, in this fifth embodiment, the sensor power management unit 6c turns on or off the communication between the vibration sensor or vital sensor 3a and the signal processing device 6 without turning on or off the power of the vibration sensor or vital sensor 3a. The turning on or off of the power of the vibration sensor or vital sensor 3a is performed according to the convenience on the side of the wearable device or smartphone 7.

[0078] According to the sensor system 21B according to the fifth embodiment, a noise vibration superimposed on the body surface displacement or a body surface displacement exhibited by the measurement target 5 is detected by the vibration sensor or vital sensor 3a incorporated in the wearable device or smartphone 7. Therefore, the configuration of the sensor system 21B is simplified by the amount of using the vibration sensor or vital sensor 3a. For this reason, while reducing the product price of the sensor system 21B, it becomes possible to reduce the power consumption of the sensor system 21B without changing the detection accuracy of the body surface displacement.

[0079] Note that, also in the sensor system 1 according to the first embodiment, the sensor system 21A according to the third embodiment, and the sensor system 21B according to the fourth embodiment, similar to the sensor system 21B according to the fifth embodiment, the second sensor 3 can be configured by a vibration sensor or a vital sensor 3a incorporated in a wearable device such as a smartwatch or a smartphone 7. Also in that case, the same operational effects as those of the sensor system 21B according to the fifth embodiment are achieved.

[0080] Also, as described with reference to FIG. 3, the sensor system 21B according to the fifth embodiment can also be appropriately arranged in the passenger compartment of the vehicle 11 with the first sensor 2 and the wearable device or smartphone 7 serving as the vibration sensor or vital sensor 3a, and applied to the driver monitoring system. Also in this case, it is possible to provide a vehicle 11 equipped with the sensor system 21B that can reduce power consumption without degrading the estimation performance of the vital signs of the human body.

Explanation of Signs

[0081] 1, 1A, 21, 21A, 21B... Sensor systems 2... First sensor 3... Second sensor 3a... Vibration sensor or vital sensor 4, 6... Signal processing devices 4a, 6b... Motion sensor determination units 4b, 6c... Sensor power management units 4c, 6a... Noise vibration removal units 4d, 6d... Vital sign detection units 5... Measurement target 7... Wearable device or smartphone

Claims

1. One or more first sensors that emit electromagnetic waves toward a measurement target, receive reflected waves that are reflected when the electromagnetic waves hit the measurement target, and detect a predetermined displacement exhibited by the measurement target; One or more second sensors that detect vibrations generated or transmitted to at least one of the measurement target or the first sensor, or the predetermined displacement; An operation sensor determination unit that determines an operation sensor that needs to operate minimally to remove or attenuate noise vibrations superimposed as noise on the predetermined displacement based on the predetermined displacement and the vibration; A sensor power management unit that supplies power only to the operation sensor A sensor system comprising the above.

2. The sensor system according to claim 1, wherein the operation sensor is the first sensor, the second sensor, a plurality of the first sensors, a plurality of the second sensors, a combination of the first sensor and the second sensor, or a plurality of combinations of the first sensor and the second sensor.

3. The sensor system according to claim 1, wherein the operation sensor determination unit determines only the first sensor or the second sensor as the operation sensor when no noise vibration is detected in either the first sensor or the second sensor.

4. The measurement target is a human body, A vital sign detection unit that detects a vital sign of the human body from a body surface displacement detected as the predetermined displacement by the operation sensor The sensor system according to claim 3, further comprising the above.

5. The total number of the first sensor and the second sensor is three or more, The sensor system according to claim 1, wherein the operation sensor determination unit determines a combination of one or more of the first sensors or one or more of the second sensors that detect the predetermined displacement and the noise vibration, and one or more of the other first sensors or one or more of the second sensors that detect the noise vibration as the operation sensor.

6. The total number of the first sensor and the second sensor is three or more, The operation sensor determination unit determines the operation sensor as a combination of one or more of the first sensors that detect the predetermined displacement and the noise vibration and one or more of the second sensors that detect the predetermined displacement and the noise vibration, and one or more of the other first sensors that detect the predetermined displacement and the noise vibration or one or more of the second sensors. The sensor system according to claim 1, characterized in that.

7. The measurement object is a human body, A noise vibration removing unit that removes or attenuates the noise vibration detected by the motion sensor from the body surface displacement detected as the predetermined displacement by the motion sensor, A vital sign detection unit that detects the vital signs of the human body from the body surface displacement from which the noise vibration has been removed or attenuated The sensor system according to claim 5 or claim 6, further comprising:

8. One or more first sensors that emit electromagnetic waves toward the measurement object and receive reflected waves that are reflected when the electromagnetic waves hit the measurement object to detect a predetermined displacement exhibited by the measurement object, One or more second sensors that detect vibrations generated or transmitted to at least one of the measurement object or the first sensor, or the predetermined displacement, Based on the predetermined displacement and the vibration, an operation for removing or attenuating noise vibration superimposed as noise on the predetermined displacement is performed for a plurality of combinations of the first sensor and the second sensor, or a plurality of combinations of the first sensor, or a plurality of combinations of the second sensor. A noise vibration removing unit, An operation sensor determination unit that determines, as an operation sensor, any one of the combinations that leads to the value closest to the true value of the predetermined displacement among the plurality of predetermined displacements obtained by removing or attenuating the noise vibration, and that needs to be operated minimally for removing or attenuating the noise vibration, A sensor power management unit that supplies power only to the operation sensor A sensor system comprising:

9. The measurement object is a human body, A vital sign detection unit that detects the vital signs of the human body from the body surface displacement calculated by the motion sensor The sensor system according to claim 8, further comprising:

10. The sensor system according to any one of claims 1 to 6, claim 8, or claim 9, wherein the second sensor is a vibration sensor incorporated in a wearable device or a smartphone.

11. The sensor system according to any one of claims 1 to 6, claim 8, or claim 9, wherein the second sensor is a vital sensor incorporated in a wearable device or a smartphone.

12. A vehicle comprising the sensor system according to any one of claims 1 to 6, claim 8, or claim 9.

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