Electronic device, method for controlling electronic device, and program

Abstract

Provided is a method for controlling an electronic device used in measuring vibration of an object on the basis of electromagnetic waves reflected from the object, the control being carried out using calibration information stored in a calibration coefficient memory, the method comprising a calibration step for calibrating a result of measurement by the electronic device on the basis of a result of measuring the vibration of a reference vibration body.

Description

Electronic device, electronic device control method, and program CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to Japanese Patent Application No. 2023-199461, filed on November 24, 2023, the entire disclosure of which is incorporated herein by reference.

[0002] The present disclosure relates to an electronic device, a control method for an electronic device, and a program.

[0003] For example, in fields such as the automotive industry, technologies for measuring the distance between a vehicle and a predetermined object have become increasingly important. In particular, in recent years, various RADAR (Radio Detecting and Ranging) technologies have been researched, which measure the distance between an object and the vehicle by transmitting radio waves such as millimeter waves and receiving the waves reflected by an object such as an obstacle. The importance of such technologies for measuring distance is expected to increase in the future with the development of technologies for assisting drivers and technologies related to autonomous driving, which automates driving partially or completely. Various technologies for detecting objects by transmitting and receiving radio waves such as millimeter waves have been proposed. For example, Patent Document 1 proposes a technology that can improve the detection accuracy of a target in a space where radio wave reflection exists.

[0004] Furthermore, a technique has been proposed in which information about vibrations at the position of a specific vibration source is obtained by using the above-mentioned radar technique (for example, Patent Document 2).

[0005] JP 2021-196195 A JP 2023-108329 A

[0006] A control method according to one embodiment is a control method for an electronic device that measures vibrations of an object based on electromagnetic waves reflected from the object using calibration information stored in a memory unit, and includes a calibration step of calibrating the measurement results of the electronic device based on the results of measuring the vibrations of a reference oscillator.

[0007] A program according to one embodiment uses calibration information stored in a memory unit to cause an electronic device that measures the vibration of an object based on electromagnetic waves reflected from the object to execute a calibration step of calibrating the measurement results of the electronic device based on the results of measuring the vibration of a reference oscillator.

[0008] An electronic device according to one embodiment includes a signal processing unit that measures the vibration of an object based on electromagnetic waves reflected from the object using calibration information stored in a memory unit, and a correction processing unit that calibrates the measurement results of the electronic device based on the results of measuring the vibration of a reference oscillator.

[0009] 1 is a diagram illustrating a usage mode of an electronic device according to an embodiment. FIG. 1 is a functional block diagram schematically illustrating the configuration of an electronic device according to an embodiment. FIG. 2 is a diagram illustrating the configuration of a signal processed by an electronic device according to an embodiment. FIG. 3 is a diagram illustrating signal processing by an electronic device according to an embodiment. FIG. 4 is a diagram illustrating signal processing by an electronic device according to an embodiment. FIG. 5 is a diagram illustrating an example of antenna arrangement and an operation principle in an antenna array of an electronic device according to an embodiment. FIG. 6 is a diagram illustrating an example of antenna arrangement in an antenna array of an electronic device according to an embodiment. FIG. 7 is a diagram illustrating an example of detection results of a vibrating body by an electronic device according to an embodiment. FIG. 8 is a diagram illustrating an example of vibration detection by an electronic device according to an embodiment. FIG. 9 is a graph illustrating an example of vibration detection results by a radar sensor. FIG. 10 is a graph illustrating an example of vibration detection results by a laser Doppler vibrometer. FIG. 11 is a graph illustrating an example of calculation results by a finite element method according to an embodiment. FIG. 12 is a diagram illustrating an example of the relationship between an FOV and a reference oscillator by an electronic device according to an embodiment. FIG. 13 is a flowchart illustrating generation of data on average vibration displacement of a reference oscillator. FIG. 14 is a flowchart illustrating operation of an electronic device according to an embodiment. FIG. 15 is a diagram illustrating an example of processing results according to an embodiment. FIG. 16 is a diagram illustrating an example of a vibrating body according to another embodiment. FIG. 17 is a diagram illustrating an example of vibration displacement of a vibrating body according to another embodiment.

[0010] For example, if it is possible to detect vibrations of a vibrating body with high accuracy by transmitting and receiving waves such as millimeter waves, it is expected that this will be useful in a wide variety of fields. An object of the present disclosure is to provide an electronic device, a control method for an electronic device, and a program that can detect vibrations of a vibrating body with high accuracy by transmitting and receiving waves. According to one embodiment, it is possible to provide an electronic device, a control method for an electronic device, and a program that can detect vibrations of a vibrating body with high accuracy by transmitting and receiving waves. Hereinafter, one embodiment will be described with reference to the drawings.

[0011] In the present disclosure, an "electronic device" may refer to a device powered by electricity. Furthermore, a "user" may refer to a person (typically a human) or an animal using an electronic device and / or a system including the electronic device according to an embodiment. A user may include a person who uses an electronic device according to an embodiment to detect vibrations of a human body, a living thing, or various objects. Furthermore, a "target" may refer to a person or thing (a monitored object, for example, a human, a living thing, or various objects) that is monitored by an electronic device according to an embodiment. Furthermore, a user may also include a target. In the present disclosure, an "target" may include, for example, an automobile, an automobile engine, a motor, a motorcycle, a ship, a building, an apartment building or other structure, a bridge, a road, a highway, a structure under construction, a tunnel, a machine tool, a shovel, and the like.

[0012] An electronic device according to an embodiment can detect the heartbeat of a target, such as a human, present in the vicinity of the electronic device. Therefore, the electronic device according to an embodiment may be used in specific facilities used by socially active individuals, such as companies, hospitals, nursing homes, schools, sports gyms, and care facilities. For example, in a company, it is extremely important to understand and / or manage the health of employees. Similarly, it is extremely important to understand and / or manage the health of patients and medical professionals in a hospital, and residents and staff in a nursing home. The electronic device according to an embodiment may be used in any facility where it is desirable to understand and / or manage the health of a target. Such facilities may also include non-commercial facilities, such as a user's home. Furthermore, the electronic device according to an embodiment may be used not only indoors but also outdoors. For example, the electronic device according to an embodiment may be used inside a moving vehicle, such as a train, bus, or airplane, or at a station or platform. Furthermore, the electronic device according to an embodiment may be used in a moving body such as an automobile, an airplane, or a ship, a hotel, a user's home, a living room, a bathroom, a toilet, or a bedroom in the home, etc. Furthermore, the electronic device according to an embodiment may be used to measure the heart rates of cows, pigs, or other livestock or animals in a zoo, a ranch, a farm, etc.

[0013] An electronic device according to an embodiment may be used, for example, in a nursing care facility or the like, to detect or monitor the heartbeat of a subject, such as a person requiring nursing care or a care recipient. Furthermore, the electronic device according to an embodiment may issue a predetermined warning to the subject and / or other persons when an abnormality is detected in the heartbeat of the subject, such as a person requiring nursing care or a care recipient. Therefore, the electronic device according to an embodiment may allow the subject and / or staff at the nursing care facility or the like to recognize that an abnormality is detected in the pulse of the subject, such as a person requiring nursing care or a care recipient. On the other hand, the electronic device according to an embodiment may notify the subject and / or other persons when no abnormality is detected in the heartbeat of the subject, such as a person requiring nursing care or a care recipient (e.g., the heartbeat is recognized as normal). Therefore, the electronic device according to an embodiment may allow the subject and / or staff at the nursing care facility or the like to recognize that the pulse of the subject, such as a person requiring nursing care or a care recipient, is normal. An electronic device according to one embodiment may determine the heartbeat interval (RR interval = RRI in an electrocardiogram) of a monitored person or animal, detect drowsiness or other distracted driving and estimate signs of such driving, estimate the level of alertness, estimate the level of fatigue, or identify the monitored person or animal, based on the heartbeat of the monitored person or animal.

[0014] Furthermore, an electronic device according to an embodiment may detect the pulse of an animal other than a human. The electronic device according to the embodiment described below will be described as detecting the vibration of a speaker (loudspeaker) as the detection target using a sensor based on technology such as millimeter-wave radar. After being calibrated based on the vibration of the speaker as described below, the electronic device configured according to the present disclosure may be used to measure the heartbeat or breathing of a human or animal, or the vibration of any other object to be measured, such as the vibration of a building or machine.

[0015] An electronic device according to an embodiment can detect not only vibrations such as the pulse of a living organism such as a human or an animal, but also vibrations of various objects. Here, the various objects may include living organisms such as a human or an animal, or any object other than a living organism such as a human or an animal. For example, an electronic device according to an embodiment may detect vibrations of various electronic devices and / or vibrations of parts of various electronic devices. Here, vibrations of various electronic devices may include vibrations caused by any vibrating body, such as vibrations associated with the operation of machinery installed in a factory, vibrations of tools, or vibrations of buildings. Furthermore, detection targets may include, for example, automobiles, automobile engines, motors, motorcycles, ships, buildings, apartment buildings and other structures, bridges, roads, highways, construction sites, tunnels, machine tools, and shovels.

[0016] An electronic device according to an embodiment may be installed on any stationary object or any mobile object. The electronic device according to an embodiment can transmit a transmission wave to the surroundings of the electronic device from a transmission antenna. The electronic device according to an embodiment can receive a reflected wave of the transmission wave from a reception antenna. At least one of the transmission antenna and the reception antenna may be provided in the electronic device, or may be provided in, for example, a radar sensor.

[0017] Hereinafter, the electronic device according to an embodiment will be described as being stationary. The electronic device according to an embodiment may be installed in a moving body such as an automobile. The electronic device according to an embodiment may be installed in a moving body such as an automobile to detect vibrations such as the heartbeat of a passenger in the moving body. Meanwhile, the object whose vibrations the electronic device according to an embodiment detects may be stationary, moving, or vibrating while stationary. The electronic device according to an embodiment can measure the distance between the electronic device and an object in a situation where the object around the electronic device may move, similar to a typical radar sensor. The electronic device according to an embodiment can measure the distance between the electronic device and an object even when both the electronic device and the object are stationary.

[0018] An electronic device according to an embodiment will be described in detail below with reference to the drawings. First, an example of object detection by the electronic device according to an embodiment will be described.

[0019] 1 is a diagram illustrating an example of a usage mode of an electronic device according to an embodiment, showing an example of an electronic device having a sensor function and including a transmitting antenna and a receiving antenna according to an embodiment.

[0020] As shown in FIG. 1 , an electronic device 1 according to an embodiment may include a transmitter and a receiver, which will be described later. As described below, the transmitter may include a transmitter antenna array 24. The receiver may include a receiver antenna array 31. Specific configurations of the electronic device 1, the transmitter, and the receiver will be described later. For ease of viewing, FIG. 1 illustrates the electronic device 1 including a transmitter antenna array 24 and a receiver antenna array 31. The electronic device 1 may also include at least one of the other functional units, such as at least a portion of the signal processing unit 10 ( FIG. 2 ), as appropriate. The electronic device 1 may also include at least one of the other functional units, such as at least a portion of the signal processing unit 10 ( FIG. 2 ), external to the electronic device 1. In FIG. 1 , the electronic device 1 may be moving or may be stationary.

[0021] In the example shown in FIG. 1 , the electronic device 1 is shown in a simplified form, with a transmitter including a transmitting antenna array 24 and a receiver including a receiving antenna array 31. The electronic device 1 may include, for example, multiple transmitters and / or multiple receivers. The transmitter may include a transmitting antenna array 24 consisting of multiple transmitting antennas. The receiver may include a receiving antenna array 31 consisting of multiple receiving antennas. Here, the locations at which the transmitters and / or receivers are installed in the electronic device 1 are not limited to the locations shown in FIG. 1 , and may be located at other locations as appropriate. The number of transmitters and / or receivers may be one or more, depending on various conditions (or requirements) such as the vibration detection range and / or detection accuracy of the electronic device 1.

[0022] As described below, the electronic device 1 transmits electromagnetic waves as transmission waves from the transmitting antenna array 24. For example, if a predetermined object (e.g., the target 200 shown in FIG. 1 ) is present around the electronic device 1, at least a portion of the transmission waves transmitted from the electronic device 1 is reflected by the object and becomes a reflected wave. Then, by receiving such a reflected wave, for example, with the receiving antenna array 31 of the electronic device 1, the electronic device 1 can detect the object as a target.

[0023] The electronic device 1 including the transmitting antenna array 24 may typically be a RADAR (Radio Detecting and Ranging) sensor that transmits and receives radio waves. However, the electronic device 1 is not limited to a radar sensor. The electronic device 1 according to an embodiment may be a sensor based on, for example, light wave-based LIDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging) technology. Such sensors may include, for example, a patch antenna. Since technologies such as RADAR and LIDAR are already known, detailed descriptions thereof may be appropriately simplified or omitted. Furthermore, the electronic device 1 according to an embodiment may be a sensor based on, for example, technology that detects objects by transmitting and receiving sound waves or ultrasonic waves.

[0024] The electronic device 1 shown in FIG. 1 receives, from the receiving antenna array 31, reflected waves of transmitted waves transmitted from the transmitting antenna array 24. In this way, the electronic device 1 can detect a predetermined object 200 present within a predetermined distance from the electronic device 1 as a target. For example, as shown in FIG. 1, the electronic device 1 can measure the distance L between the electronic device 1 and the predetermined object 200. The electronic device 1 can also measure the relative speed between the electronic device 1 and the predetermined object 200. Furthermore, the electronic device 1 can also measure the direction (arrival angle θ) in which the reflected wave from the predetermined object 200 arrives at the electronic device 1.

[0025] In Fig. 1, the XY plane may be, for example, a plane substantially parallel to the ground surface. In this case, the positive direction of the Z axis shown in Fig. 1 may indicate a vertically upward direction. In Fig. 1, the electronic device 1 may be disposed on a plane parallel to the XY plane. Also, in Fig. 1, the target 200 may be, for example, standing on the ground surface substantially parallel to the XY plane.

[0026] Here, the target 200 may be, for example, a human being present around the electronic device 1. The target 200 may also be a non-human living entity, such as an animal present around the electronic device 1. The target 200 may also include, for example, automobiles, automobile engines, motors, motorcycles, boats, buildings, apartment buildings, and other structures, bridges, roads, highways, construction sites, tunnels, machine tools, and excavators present around the electronic device 1. As described above, the target 200 may be moving, stationary, or static. In the present disclosure, the object detected by the electronic device 1 includes not only inanimate objects such as any object, but also living entities such as people, dogs, cats, horses, and other animals. The object detected by the electronic device 1 of the present disclosure may include targets, including people, objects, and animals, detected using radar technology. In the present disclosure, the target may include people, objects, and animals. Hereinafter, the object such as the target 200 present around the electronic device 1 will be described assuming that it is a living or inanimate object. The electronic device 1 according to one embodiment detects vibrations of an object such as the object 200. Therefore, hereinafter, the "object 200" will also be referred to as the "vibrating body 200" as appropriate.

[0027] 1, the ratio between the size of the electronic device 1 and the size of the target 200 does not necessarily represent the actual ratio. Also, in FIG. 1, the transmitting antenna array 24 of the transmitting unit and the receiving antenna array 31 of the receiving unit are shown installed outside the electronic device 1. However, in one embodiment, the transmitting antenna array 24 of the transmitting unit and / or the receiving antenna array 31 of the receiving unit may be installed at various positions on the electronic device 1. For example, in one embodiment, the transmitting antenna array 24 of the transmitting unit and / or the receiving antenna array 31 of the receiving unit may be installed inside the electronic device 1 so as not to be visible from the outside of the electronic device 1.

[0028] In the following description, as a typical example, the transmitting antenna of the electronic device 1 will be described as transmitting radio waves in a frequency band such as millimeter waves (30 GHz or higher) or quasi-millimeter waves (e.g., around 20 GHz to 30 GHz). Alternatively, the transmitting antenna of the electronic device 1 may transmit radio waves having a frequency bandwidth of 4 GHz, such as 77 GHz to 81 GHz. Furthermore, the transmitting antenna of the electronic device 1 may transmit radio waves at a frequency higher than the millimeter wave band (e.g., 30 GHz to 300 GHz).

[0029] 2 is a functional block diagram illustrating an example of the configuration of the electronic device 1 according to an embodiment. An example of the configuration of the electronic device 1 according to an embodiment will be described below.

[0030] When measuring distances and the like using millimeter-wave radar, frequency-modulated continuous-wave radar (hereinafter referred to as FMCW radar) is often used. FMCW radar generates a transmission signal by sweeping the frequency of the radio waves to be transmitted. Therefore, in a millimeter-wave FMCW radar using radio waves in the 79 GHz frequency band, for example, the frequency of the radio waves used has a frequency bandwidth of 4 GHz, such as 77 GHz to 81 GHz. Radar using the 79 GHz frequency band is characterized by a wider usable frequency bandwidth than other millimeter-wave / quasi-millimeter-wave radars, such as those using the 24 GHz, 60 GHz, and 76 GHz frequency bands. Hereinafter, such an embodiment will be described as an example.

[0031] The FMCW radar system used in the present disclosure may include an FCM (Fast-Chirp Modulation) system that transmits chirp signals at a shorter period than normal. The signals generated by the electronic device 1 are not limited to FMCW signals. The signals generated by the electronic device 1 may be signals of various systems other than FMCW. The transmission signal sequence stored in any memory unit may differ depending on these various systems. For example, in the case of the above-mentioned FMCW radar signal, signals whose frequency increases and decreases with each time sample may be used. Since known technologies can be applied as appropriate to the above-mentioned various systems, further detailed description will be omitted.

[0032] As shown in FIG. 2 , the electronic device 1 according to one embodiment includes a signal processing unit 10. The signal processing unit 10 may include a signal generation processing unit 11, a received signal processing unit 12, a correction processing unit 13, a calibration coefficient memory 14, and a waveform analysis processing unit 15. The signal generation processing unit 11 generates a transmission signal to be transmitted from the electronic device 1. The received signal processing unit 12 can perform various signal processing operations on the received signal received by the electronic device 1. The correction processing unit 13 can perform correction operations on the results of the signal processing performed by the received signal processing unit 12. The calibration coefficient memory 14 stores data (e.g., calibration coefficients or correction values) based on the results of the correction processing performed by the correction processing unit 13. The waveform analysis processing unit 15 can perform waveform analysis operations on the results of the correction performed by the correction processing unit 13, for example. The signal generation processing unit 11, the received signal processing unit 12, the correction processing unit 13, the calibration coefficient memory 14, and the waveform analysis processing unit 15 will be described in further detail below. In this embodiment, the calibration coefficient memory 14 is described as being included in the signal processing unit 10; however, the calibration coefficient memory 14 may be provided external to the electronic device 1. Calibration coefficient memory 14 may be connected to electronic device 1 via a network that is wired, wireless, or a combination of these, and may transmit data in calibration coefficient memory 14 to correction processing unit 13 or the like of electronic device 1. Calibration coefficient memory 14 may be a storage medium that is detachable from electronic device 1, and the data in calibration coefficient memory 14 may be transmitted from the storage medium to correction processing unit 13 or the like of electronic device 1.

[0033] The electronic device 1 according to an embodiment includes a transmitting unit including a transmitting DAC 21, a transmitting circuit 22, a millimeter-wave transmitting circuit 23, and a transmitting antenna array 24. The electronic device 1 according to an embodiment includes a receiving unit including a receiving antenna array 31, a mixer 32, a receiving circuit 33, and a receiving ADC 34. The electronic device 1 according to an embodiment may not include at least one of the functional units shown in FIG. 2 , or may include functional units other than the functional units shown in FIG. 2. The electronic device 1 shown in FIG. 2 may be configured using a circuit configured basically similarly to a general radar using electromagnetic waves in the millimeter-wave band or the like. Meanwhile, in the electronic device 1 according to an embodiment, the signal processing by the signal processing unit 10 may include processing different from that of conventional general radar.

[0034] The signal processing unit 10 included in the electronic device 1 according to an embodiment can control the overall operation of the electronic device 1, including the control of each functional unit constituting the electronic device 1. In particular, the signal processing unit 10 performs various processes on signals handled by the electronic device 1. The signal processing unit 10 may include at least one processor, such as a central processing unit (CPU) or a digital signal processor (DSP), to provide control and processing capabilities for executing various functions. The signal processing unit 10 may be implemented as a single processor, several processors, or individual processors. The processor may be implemented as a single integrated circuit. An integrated circuit is also referred to as an IC (integrated circuit). The processor may be implemented as multiple integrated circuits and discrete circuits connected to each other in a communicative manner. The processor may also be implemented based on various other known technologies. In an embodiment, the signal processing unit 10 may be configured as, for example, a CPU (hardware) and a program (software) executed by the CPU. At least a portion of the functional units constituting the electronic device 1 according to an embodiment may be implemented by specific means in which software and hardware resources work together. The signal processing unit 10 may include a storage unit (memory) necessary for the operation of the signal processing unit 10 as appropriate.

[0035] The signal generation processing unit 11 of the signal processing unit 10 generates a signal to be transmitted from the electronic device 1. In one embodiment of the electronic device 1, the signal generation processing unit 11 may generate a transmission signal (transmission chirp signal) such as a chirp signal. In particular, the signal generation processing unit 11 may generate a signal whose frequency changes periodically and linearly (linear chirp signal). For example, the signal generation processing unit 11 may generate a chirp signal whose frequency periodically and linearly increases from 77 GHz to 81 GHz over time. Alternatively, the signal generation processing unit 11 may generate a signal whose frequency periodically and linearly increases (up-chirp) and decreases (down-chirp) from 77 GHz to 81 GHz over time. The signal generated by the signal generation processing unit 11 may be preset in the signal processing unit 10, for example. Alternatively, the signal generated by the signal generation processing unit 11 may be pre-stored in, for example, an arbitrary storage unit in the signal processing unit 10. Since chirp signals used in technical fields such as radar are well known, a more detailed description thereof will be simplified or omitted as appropriate. The signal generated by the signal generation processing unit 11 is supplied to the transmission DAC 21. For this purpose, the signal generation processing unit 11 may be connected to the transmission DAC 21.

[0036] The transmission DAC (digital-to-analog converter) 21 has a function of converting the digital signal supplied from the signal generation processing unit 11 into an analog signal. The transmission DAC 21 may be configured to include a general digital-to-analog converter. The analog signal converted by the transmission DAC 21 is supplied to the transmission circuit 22. For this reason, the transmission DAC 21 may be connected to the transmission circuit 22.

[0037] The transmission circuit 22 has a function of converting the analog signal converted by the transmission DAC 21 into an intermediate frequency (IF) band. The transmission circuit 22 may be configured to include a general IF band transmission circuit. The signal processed by the transmission circuit 22 is supplied to the millimeter wave transmission circuit 23. For this reason, the transmission circuit 22 may be connected to the millimeter wave transmission circuit 23.

[0038] The millimeter-wave transmission circuit 23 has a function of transmitting the signal processed by the transmission circuit 22 as a millimeter wave (RF wave). The millimeter-wave transmission circuit 23 may be configured to include a general millimeter-wave transmission circuit. The signal processed by the millimeter-wave transmission circuit 23 is supplied to the transmission antenna array 24. For this reason, the millimeter-wave transmission circuit 23 may be connected to the transmission antenna array 24. The signal processed by the millimeter-wave transmission circuit 23 is also supplied to the mixer 32. For this reason, the millimeter-wave transmission circuit 23 may also be connected to the mixer 32.

[0039] The transmitting antenna array 24 is an array of multiple transmitting antennas. Fig. 2 shows a simplified configuration of the transmitting antenna array 24. The transmitting antenna array 24 transmits the signal processed by the millimeter-wave transmitting circuit 23 to the outside of the electronic device 1. The transmitting antenna array 24 may be configured to include a transmitting antenna array used in a general millimeter-wave radar.

[0040] In this way, the electronic device 1 according to the embodiment includes a transmitting antenna (transmitting antenna array 24 ) and can transmit a transmitting signal (for example, a transmitting chirp signal) as a transmitting wave from the transmitting antenna array 24 .

[0041] For example, as shown in Fig. 2, assume that an object such as a vibrating body 200 is present around the electronic device 1. At least a portion of the vibrating body 200 may generate vibrations. In this situation, at least a portion of the transmission waves transmitted from the transmitting antenna array 24 is reflected by the object such as the vibrating body 200. At least a portion of the transmission waves transmitted from the transmitting antenna array 24 and reflected by the object such as the vibrating body 200 may be reflected toward the receiving antenna array 31.

[0042] The receiving antenna array 31 receives the reflected waves. Here, the reflected waves may be at least a portion of the transmission waves transmitted from the transmitting antenna array 24 that are reflected by an object such as the vibrating body 200.

[0043] The receiving antenna array 31 is an array of multiple receiving antennas. In FIG. 2, the configuration of the receiving antenna array 31 is shown in a simplified form. The receiving antenna array 31 receives reflected waves that are the result of reflection of the transmitted waves transmitted from the transmitting antenna array 24. The receiving antenna array 31 may be configured to include a receiving antenna array used in a general millimeter-wave radar. The receiving antenna array 31 supplies the received signals received as reflected waves to the mixer 32. For this reason, the receiving antenna array 31 may be connected to the mixer 32.

[0044] The mixer 32 converts the signal (transmission signal) processed by the millimeter-wave transmission circuit 23 and the reception signal received by the reception antenna array 31 into an intermediate frequency (IF) band. The mixer 32 may be configured to include a mixer used in a general millimeter-wave radar. The mixer 32 supplies the signal generated as a result of the combination to the reception circuit 33. For this reason, the mixer 32 may be connected to the reception circuit 33.

[0045] The receiving circuit 33 has a function of performing analog processing on the signal converted to the IF band by the mixer 32. The receiving circuit 33 may be configured to include a receiving circuit that converts to a general IF band. The signal processed by the receiving circuit 33 is supplied to the receiving ADC 34. For this reason, the receiving circuit 33 may be connected to the receiving ADC 34.

[0046] The receiving ADC (analog-to-digital converter) 34 has a function of converting the analog signal supplied from the receiving circuit 33 into a digital signal. The receiving ADC 34 may be configured to include a general analog-to-digital converter. The signal digitized by the receiving ADC 34 is supplied to the receiving signal processing unit 12 of the signal processing unit 10. For this reason, the receiving ADC 34 may be connected to the signal processing unit 10.

[0047] The reception signal processing unit 12 of the signal processing unit 10 has the function of performing various processes on the digital signal supplied from the reception ADC 34. For example, the reception signal processing unit 12 calculates the distance from the electronic device 1 to an object such as the vibrating body 200 based on the digital signal supplied from the reception ADC 34 (distance measurement). The reception signal processing unit 12 also calculates the relative velocity of the object such as the vibrating body 200 with respect to the electronic device 1 based on the digital signal supplied from the reception ADC 34 (velocity measurement). Furthermore, the reception signal processing unit 12 calculates the azimuth angle of the object such as the vibrating body 200 as seen from the electronic device 1 based on the digital signal supplied from the reception ADC 34 (angle measurement or angle of arrival estimation). Specifically, I / Q converted data may be input to the reception signal processing unit 12. By inputting such data, the reception signal processing unit 12 performs fast Fourier transforms (2D-FFT) in the range direction and velocity direction, respectively. Thereafter, the reception signal processing unit 12 may suppress false alarms by removing noise points through processing such as CFAR (Constant False Alarm Rate) and make the probability of false alarms constant. Then, the reception signal processing unit 12 estimates the angle of arrival for points that satisfy the CFAR criteria, thereby obtaining the position of an object such as the vibrating body 200. Information generated as a result of measuring the distance, speed, and angle by the reception signal processing unit 12 may be supplied to the correction processing unit 13.

[0048] The correction processing unit 13 corrects the information generated by the received signal processing unit 12. The correction processing by the correction processing unit 13 will be described further below. Information about the vibration of the vibrating body corrected by the correction processing unit 13 may be supplied to a calibration coefficient memory 14 and / or a waveform analysis processing unit 15, etc.

[0049] The calibration coefficient memory 14 stores data (for example, calibration coefficients or correction values) based on the results of the correction processing performed by the correction processing unit 13 .

[0050] The waveform analysis processing unit 15 analyzes the vibration waveform by performing various calculation processes and / or arithmetic processes on information about the vibration of the vibrating body supplied from the correction processing unit 13 or the calibration coefficient memory 14. The various calculation processes and / or arithmetic processes performed by the waveform analysis processing unit 15 will be described further below. The waveform information analyzed by the waveform analysis processing unit 15 may be supplied to, for example, a communication interface 50. For this reason, the waveform analysis processing unit 15 and / or the signal processing unit 10 may be connected to the communication interface 50. The various information calculated and / or processed by the signal processing unit 10 may be supplied to other functional units other than the communication interface 50.

[0051] The communication interface 50 is configured to include an interface that outputs information supplied from the signal processing unit 10 to, for example, an external device 60. The communication interface 50 may output at least one of information regarding the position, velocity, and angle of an object such as the vibrating body 200 to the external device 60 as a signal such as a CAN (Controller Area Network). For example, at least one of information regarding the position, velocity, and angle of an object such as the vibrating body 200 may be supplied to the external device 60 via the communication interface 50. For this reason, the communication interface 50 may be connected to the external device 60.

[0052] 2 , the electronic device 1 according to an embodiment may be connected to an external device 60 via a communication interface 50 in a wired or wireless manner. In an embodiment, the external device 60 may include any computer and / or any control device. The electronic device 1 according to an embodiment may also include the external device 60. The external device 60 may have various configurations depending on how the information about vibrations detected by the electronic device 1 is used. Therefore, a detailed description of the external device 60 will be omitted.

[0053] FIG. 3 is a diagram illustrating an example of a chirp signal generated by the signal generation processing unit 11 of the signal processing unit 10. In FIG.

[0054] FIG. 3 shows the time structure of one frame when using the FCM (Fast-Chirp Modulation) method. FIG. 3 shows an example of a received signal in the FCM method. FCM is a method in which chirp signals shown as c1, c2, c3, c4, ..., cn in FIG. 3 are repeated at relatively short intervals (for example, equal to or longer than the round-trip time between the electromagnetic wave radar and the target, calculated from the maximum ranging distance). In FCM, for convenience of signal processing of the received signal, transmission and reception processing is often performed by dividing the signal into subframe units as shown in FIG. 3.

[0055] In Fig. 3, the horizontal axis represents elapsed time, and the vertical axis represents frequency. In the example shown in Fig. 3, the signal generation processing unit 11 generates linear chirp signals whose frequencies change periodically and linearly. In Fig. 3, each chirp signal is represented as c1, c2, c3, c4, ..., cn. As shown in Fig. 3, the frequency of each chirp signal increases linearly over time.

[0056] In the example shown in FIG. 3 , several chirp signals such as c1, c2, c3, c4, ..., cn are included in one subframe. That is, subframe 1 and subframe 2 shown in FIG. 3 are each composed of several chirp signals such as c1, c2, c3, c4, ..., cn. Also, in the example shown in FIG. 3 , several subframes such as subframe 1, subframe 2, ..., subframe N are included in one frame (one frame). That is, one frame shown in FIG. 3 is composed of N subframes. Also, one frame shown in FIG. 3 may be frame 1, followed by frame 2, frame 3, ..., etc. Each of these frames may be composed of N subframes, just like frame 1. Also, a frame interval of a predetermined length may be included between frames. One frame shown in FIG. 3 may be, for example, 30 to 50 milliseconds long.

[0057] In the electronic device 1 according to an embodiment, the signal generation processing unit 11 may generate a transmission signal having any number of frames. Also, some chirp signals are omitted from the illustration in Fig. 3. In this manner, the relationship between time and frequency of the transmission signal generated by the signal generation processing unit 11 may be stored as various setting parameters in, for example, a storage unit of the signal processing unit 10.

[0058] In this manner, the electronic device 1 according to an embodiment may transmit a transmission signal composed of subframes each including a plurality of chirp signals. Also, the electronic device 1 according to an embodiment may transmit a transmission signal composed of a frame each including a predetermined number of subframes.

[0059] Hereinafter, the electronic device 1 will be described as transmitting a transmission signal having a frame structure as shown in FIG. 3 . However, the frame structure as shown in FIG. 3 is merely an example, and for example, the number of chirp signals included in one subframe may be arbitrary. That is, in one embodiment, the signal generation processing unit 11 may generate subframes including any number (e.g., any plural number) of chirp signals. Also, the subframe structure as shown in FIG. 3 is merely an example, and for example, the number of subframes included in one frame may be arbitrary. That is, in one embodiment, the signal generation processing unit 11 may generate frames including any number (e.g., any plural number) of subframes. The signal generation processing unit 11 may generate signals of different frequencies. The signal generation processing unit 11 may generate multiple discrete signals, each having a frequency f with a different bandwidth.

[0060] Fig. 4 is a diagram showing, in another aspect, part of the subframe shown in Fig. 3. Fig. 4 shows each sample of the received signal that has received the transmitted signal shown in Fig. 3 as a result of 2D-FFT (Two Dimensional Fast Fourier Transform) processing performed by the received signal processing unit 12 (Fig. 2) of the signal processing unit 10.

[0061] As shown in Fig. 4, chirp signals c1, c2, c3, c4, ..., cn are stored in each subframe, such as subframe 1, ..., subframe N. In Fig. 4, each chirp signal c1, c2, c3, c4, ..., cn is composed of samples, each represented by a square arranged in the horizontal direction. The received signal shown in Fig. 4 is subjected to 2D-FFT, CFAR, and / or integrated signal processing of each subframe by the received signal processing unit 12 shown in Fig. 2.

[0062] FIG. 5 is a diagram showing an example of a point cloud calculated on a range-Doppler (distance-velocity) plane as a result of 2D-FFT, CFAR, and integrated signal processing of each subframe being performed in the received signal processing unit 12 shown in FIG.

[0063] In FIG. 5 , the horizontal direction represents range (Rance) and the vertical direction represents velocity (Velocity). The filled squares s1 in FIG. 5 represent point clouds indicating signals that exceed the CFAR threshold processing. The unfilled squares s2 in FIG. 5 represent bins (2D-FFT samples) without point clouds that do not exceed the CFAR threshold. The point clouds on the range-Doppler plane calculated in FIG. 5 have their azimuth from the radar calculated by direction estimation, and their position and velocity on a two-dimensional plane are calculated as point clouds indicating an object such as the vibrating body 200. Here, the direction estimation may be calculated using a beamformer and / or a subspace method. Representative subspace method algorithms include MUSIC (MUltiple SIgnal Classification) and ESPRIT (Estimation of Signal Parameters via Rotation Invariance Technique).

[0064] FIG. 6 is a diagram showing an example of the results of the conversion of point cloud coordinates from the range-Doppler plane shown in FIG. 5 to the XY plane after the received signal processing unit 12 has performed direction estimation. The XY plane shown in FIG. 6 may be the same as the XY plane shown in FIG. 1. As shown in FIG. 6, the received signal processing unit 12 can plot a point cloud PG on the XY plane. Here, the point cloud PG is made up of individual points P. Furthermore, each point P has an angle θ and a radial velocity Vr in polar coordinates.

[0065] The received signal processing unit 12 detects an object present within the range in which the transmitted wave is transmitted based on at least one of the results of the 2D-FFT and the angle estimation. The received signal processing unit 12 may perform object detection by, for example, performing clustering processing based on the estimated distance information, velocity information, and angle information. Known algorithms used for clustering data include DBSCAN (Density-based spatial clustering of applications with noise). This is an algorithm that performs clustering based on density. In the clustering processing, for example, the average power of the points constituting the detected object may be calculated. The distance information, velocity information, angle information, and power information of the object detected by the received signal processing unit 12 may be supplied to an external device 60, for example, via a communication interface 50.

[0066] As described above, the electronic device 1 may include a transmitting antenna (transmitting antenna array 24), a receiving antenna (receiving antenna array 31), and a signal processing unit 10. The transmitting antenna array 24 transmits a transmission wave, for example, an electric wave. The receiving antenna array 31 receives a reflected wave of the transmission wave. The signal processing unit 10 then detects an object (such as the vibrating body 200) that reflects the transmission wave based on the transmission signal transmitted as the transmission wave and the reception signal received as the reflected wave.

[0067] Next, estimation of the direction of an incoming wave (an incoming reflected wave) by the antenna array of the electronic device 1 according to an embodiment will be further described.

[0068] 7 is a diagram illustrating the configuration of the receiving antenna array 31 of the electronic device 1 according to an embodiment and the principle of estimating the direction of an incoming wave by the receiving antenna array 31. FIG. 7 shows an example of reception of radio waves by the receiving antenna array 31.

[0069] As shown in Figure 7, the receive antenna array 31 may be a linear arrangement of sensors such as receive antennas. As shown in Figure 7, in one embodiment, the receive antenna array 31 may include multiple receive antennas arranged in a linear arrangement. In Figure 7, the receive antenna array 31 includes antenna x １ , x ２ , x ３ , …, x Ｍ The receiving antenna array 31 may be composed of any number of antennas. As shown in FIG. 7, the multiple antennas constituting the receiving antenna array 31 are arranged at an interval of an array pitch d. A sensor array in which sensors (antennas, ultrasonic vibrators, microphones, etc.) corresponding to various physical waves are arranged in an array is also called a Uniform Linear Array (ULA). As shown in FIG. 7, physical waves (electromagnetic waves, sound waves, etc.) are transmitted along a direction, for example, θ １ and θ ２ where θ １ and θ ２ may be the angle of arrival described above. In this way, a sensor array such as the receiving antenna array 31 can estimate the direction of arrival (angle of arrival) by utilizing the phase difference that occurs in the measurements between sensors depending on the direction of arrival of the physical wave. This method of estimating the direction of arrival of a wave is also referred to as angle of arrival estimation or direction of arrival (DoA).

[0070] In the electronic device 1 according to one embodiment, at least one of the transmitting antenna array 24 and the receiving antenna array 31 may be configured with multiple antennas arranged in a line. This allows, for example, millimeter-wave radar to appropriately narrow the directivity when transmitting and receiving radio waves. When transmitting a transmitted wave, the direction of the transmitted beam is often controlled by a beamformer. On the other hand, when receiving a reflected wave, the direction of arrival of the reflected wave is often estimated using a subspace method (such as the above-mentioned MUSIC and ESPRIT) rather than a beamformer. In the beamformer and subspace method, in a ULA such as that shown in FIG. 7 , a phase difference occurs in the measurements between sensors depending on the direction of arrival of electromagnetic waves arriving from various directions. Therefore, the phase difference can be used to estimate the direction of arrival of the reflected wave.

[0071] Next, estimation of angles of incoming waves in two directions by the antenna array of the electronic device 1 according to an embodiment will be further described.

[0072] FIG. 8 is a diagram showing an example of an antenna arrangement for estimating the directions of arrival at two orthogonal angles.

[0073] As shown in FIG. 8, in the electronic device 1 according to one embodiment, the transmitting antenna array 24 and / or the receiving antenna array 31 may be configured to include an array of a plurality of patch antenna units.

[0074] In the transmitting antenna array 24 shown in Fig. 8, one patch antenna unit may be configured to include a plurality of elements electrically connected in the direction 1 shown in the figure. In each patch antenna unit, the plurality of elements may be electrically connected by wiring such as a strip line on a substrate. In each patch antenna unit, the plurality of elements are spaced apart at intervals d shorter than half the wavelength λ of the transmitting wave. １，ｔ 8, each patch antenna unit may have any number of elements greater than or equal to two electrically connected together.

[0075] 8, the transmitting antenna array 24 may be configured by arranging a plurality of patch antenna units in a direction 2 shown in the figure. The patch antenna units are spaced apart at intervals d, which are shorter than half the wavelength λ of the transmitting wave. ２，ｔ In one embodiment, the transmit antenna array 24 may include any number of patch antenna units greater than or equal to two.

[0076] As shown in Fig. 8, in one embodiment, the receiving antenna array 31 may be configured by changing the arrangement of the multiple elements in the transmitting antenna array 24. That is, in the receiving antenna array 31 shown in Fig. 8, one patch antenna unit may be configured to include multiple elements electrically connected in the direction 2 shown in the figure. In each patch antenna unit, the multiple elements may be electrically connected by wiring such as a stripline on a substrate. In each patch antenna unit, the multiple elements are spaced apart at intervals d shorter than half the wavelength λ of the transmission wave. ２，ｓ 8, each patch antenna unit may have any number of elements greater than or equal to two electrically connected together.

[0077] 8, the receiving antenna array 31 may be configured by arranging a plurality of patch antenna units in a direction 1 shown in the figure. The patch antenna units are spaced apart at intervals d, which are shorter than half the wavelength λ of the transmission wave. １，ｓ In one embodiment, the receive antenna array 31 may include any number of patch antenna units greater than or equal to two.

[0078] The elements included in the transmitting antenna array 24 and the receiving antenna array 31 may all be arranged on the same plane (for example, on the surface layer of the same substrate). The transmitting antenna array 24 and the receiving antenna array 31 may also be arranged close to each other (monostatically). Furthermore, directions 1 and 2 shown in FIG. 8 may be geometrically orthogonal to each other.

[0079] The transmitting antenna array 24 and the receiving antenna array 31 shown in FIG. 8 can appropriately narrow the directivity of each of the transmitting antennas and the receiving antennas. Furthermore, by using the transmitting antenna array 24 shown in FIG. 8 to control the direction of transmission of each transmission wave (transmission signal) at each timing of transmission, a beamformer for direction 2 shown in FIG. 8 can be realized. Furthermore, by using the receiving antenna array 31 shown in FIG. 8, the arrival direction of the reflected wave can be estimated for direction 1 shown in FIG. 8. In this way, it is possible to estimate the arrival direction of the reflected wave for two angles that are substantially orthogonal. Therefore, it is possible to obtain a point cloud representing an object such as the vibrating body 200 in three dimensions.

[0080] Next, a method for detecting vibration of the vibrating body 200 using the electronic device 1 according to an embodiment will be described.

[0081] As described above, millimeter-wave radar sensors (millimeter-wave sensors) can detect vibrations of objects by using the micro-Doppler phenomenon. Millimeter-wave sensors can measure distance and / or angle. Therefore, by narrowing down the area in which distance and / or angle measurement is performed, millimeter-wave sensors can measure the average vibration displacement within a range (surface) included in that area. However, it is not necessarily easy to measure the average vibration displacement within a predetermined range (surface) using vibration sensors other than millimeter-wave sensors. Therefore, ingenuity is required to calibrate a millimeter-wave sensor using another vibration sensor that has already been calibrated. If a millimeter-wave sensor could be calibrated using another sensor that can detect vibrations more accurately, the vibration of a vibrating body could be detected with high accuracy by transmitting and receiving millimeter waves. If the vibration of a vibrating body could be detected with high accuracy by transmitting and receiving waves such as millimeter waves, it is expected to be useful in a wide variety of fields.

[0082] Hereinafter, a mode in which the millimeter wave sensor is calibrated using another sensor that can detect vibrations more accurately will be described.

[0083] The following describes how, for example, the vibrating body 200 is detected on the 2D-FFT plane as a result of 2D-FFT (FIGS. 3 and 4) using a sensor based on millimeter-wave radar technology, such as the electronic device 1 according to one embodiment.

[0084] FIG. 9 is a diagram showing an example of the results of 2D-FFT processing when the vibrating body 200 is measured by the electronic device 1 according to an embodiment. The graph shown in FIG. 9 shows the overall results of 2D-FFT processing executed by the signal processing unit 10 (the reception signal processing unit 12) of the electronic device 1 according to an embodiment. The horizontal axis of the graph shown in FIG. 9 represents distance (range), and the vertical axis represents velocity. The graph shown in FIG. 9 indicates that, within the distance range of approximately 0 to 6.3 m, the brighter the color, the stronger the signal strength. The area where a spectrum indicating the vibration of the vibrating body 200 exists is shown near the distance R1 shown in FIG. 9. The spectral components shown near the distance R1 contain information about the vibration caused by the vibrating body 200.

[0085] In the 2D-FFT processed data shown in FIG. 9, the vibration data of the vibrating body 200 is filtered by extracting only the signals of range bins in the bright colored portion in the distance range of 0 to 6.3 m, and the filtered data is called data S(Ω Ｒ [m], Ω Ｄ This data S(Ω Ｒ [m], Ω Ｄ By performing an inverse Fourier transform on s(t[n]), an intermediate frequency signal (I / F signal) mainly containing only the vibration of the vibrating body 200 is obtained. Ｒ , t Ｄ ) can be obtained, where Ω Ｒ [m] and Ω Ｄ [n] indicates the range frequency and Doppler frequency on the 2D-FFT, respectively. Ｒ [l], t Ｄ [k] are the time sampling times of the I / F signal. Since these are all discrete values, the I / F signal is reconstructed by discrete Fourier transform as shown in the following equation (1).

[0086]

[0087] The vibration waveform is calculated from the I / F signal containing the vibration of the vibrating body 200 obtained by the above formula (1) as follows: First, addition is performed in the range sampling direction of the I / F signal as shown in the following formula (2).

[0088]

[0089] Finally, the complex signal vector s ｓｕｍ By taking the argument on the Gaussian plane and multiplying it by a coefficient, a time series vector of vibration displacement can be obtained as shown in the following equation (3).

[0090]

[0091] Next, as an example, a model will be described in which the vibration of the vibrating body 200 configured as a loudspeaker is measured by the electronic device 1 configured as a millimeter wave sensor.

[0092] 10 is a diagram showing a model of an embodiment in which the electronic device 1 measures the vibration of a vibrating body 200. As shown in FIG. 10, the vibrating body 200 may be, for example, a loudspeaker. The electronic device 1 according to the embodiment may also include a millimeter wave sensor.

[0093] 10 , the electronic device 1 includes a transmitting antenna array 24 and a receiving antenna array 31. A transmission wave transmitted from the transmitting antenna array 24 reaches the vibrating body 200 after traveling a distance R. At least a portion of the transmission wave transmitted from the transmitting antenna array 24 is reflected by the vibrating body 200 to become a reflected wave. The reflected wave reflected by the vibrating body 200 reaches the electronic device 1 after traveling a distance R and is received by the receiving antenna array 31. In this way, the electronic device 1 transmits and receives radio waves to perform the above-described processing on the vibrating body 200.

[0094] 10, the vibrating body 200 is shown schematically. In the vibrating body 200 shown in FIG. 10, a frame portion Γ that forms the outer frame of the loudspeaker １The vibrating body 200 is made of a highly rigid material such as metal. ２ is bonded using a dome made of a low-elasticity material. ３ is a cone-type diaphragm Γ ２ and frame section Γ １ Connect the edge Γ ３ is made of elastic material, so the cone-shaped diaphragm Γ ２ is the frame part Γ １ The cone-shaped diaphragm Γ is connected in a movable state to the ２ is electrically driven by a magnetic circuit consisting of a magnet, a yoke, a voice coil, etc.

[0095] As an example, the cone-type diaphragm Γ ２ The diaphragm 200 is made of a metal such as aluminum. With this configuration, millimeter waves are completely reflected by the metal diaphragm surface. Therefore, in this configuration, the radar cross section (RCS) is simplified as the area of ​​the orthogonal projection of the entire diaphragm 200 as viewed from the antenna surface of the electronic device 1.

[0096] The I / F signal s(t Ｒ [l], t Ｄ [k]) is an I / F signal obtained by adding and mixing all the reflected waves from the entire vibrating body 200 as seen from the electronic device 1, which is a millimeter wave sensor. Therefore, the vibration displacement in the above equation (3) is an average of the vibrations of the entire surface of the vibrating body 200, as shown in the following equation (4).

[0097]

[0098] In the above formula (4), σ represents the area of ​​the orthogonal projection of the vibrating body 200 (loudspeaker) as seen from the electronic device 1 (millimeter wave sensor). R represents the distance between the electronic device 1 and the vibrating body 200. Γ represents the entire area of ​​the vibrating body 200. １ indicates the frame part that can be considered vibrationally fixed. ２ indicates the cone-type diaphragm, which is the diaphragm of the loudspeaker.ｖｉｂ (R) indicates the vibration displacement at the distance R from the electronic device 1.

[0099] The above formula (4) indicates that the vibration of the vibrating body 200 is affected by the frame portion Γ, which can be regarded as being vibrationally fixed. １ and the influence of the cone diaphragm Γ ２ The first term on the right-hand side of the above formula (4) represents the influence of the vibrationally fixed frame portion Γ. １ In this way, the vibrationally fixed frame part Γ １ The contribution of is not necessary for measuring vibration displacement. １ contributes as a bias to the constant or slow vibration displacement. １ It is desirable to exclude the contribution of

[0100] Frame section Γ １ It is difficult to eliminate the influence of the contribution of the frame portion Γ by ordinary millimeter wave radar signal processing, i.e., signal processing such as 2D-FFT processing, CFAR processing, and range bin filtering. １ The influence of the contribution of the vibration waveform time series vector D ｖｉｂ It is conceivable to remove the millimeter-wave sensor from the electronic device 1 by frequency filtering or the like. However, even if such filtering is performed, it is difficult to completely remove the influence on the vibration displacement. It is also expected that perturbations of the vibration displacement due to other influences may be added. Therefore, when the electronic device 1 according to an embodiment is configured to include a millimeter-wave sensor, the millimeter-wave sensor needs to be calibrated using a reference measuring instrument.

[0101] Next, a problem that arises when calibrating the electronic device 1 that includes a millimeter wave sensor will be described.

[0102] FIG. 11A is a graph showing the waveform of vibration displacement of a loudspeaker at 750 Hz measured by a millimeter-wave sensor (electronic device 1). FIG. 11B is a graph showing the waveform of vibration displacement of the same loudspeaker at 750 Hz measured by a laser Doppler vibrometer (LDV). Both FIGS. 11A and 11B show an example in which a voltage with a frequency of 750 Hz is applied to the loudspeaker and the voltage is increased in steps. In both FIGS. 11A and 11B, the horizontal axis represents elapsed time and the vertical axis represents vibration displacement. The LDV measures vibration at a single point irradiated by the laser (e.g., the center point on the dust cap of the loudspeaker). In contrast, the millimeter-wave sensor measures the average value of vibration displacement by measuring the entire vibrating surface. 11A and 11B, there is a difference of about 10 to 20% between the measured values ​​of the two (the measurement results by the millimeter-wave sensor are about 10 to 20% smaller). Therefore, it is difficult to calibrate the millimeter-wave sensor itself by simply comparing the measurement results of vibration at a single point by the LDV with the measurement results by the millimeter-wave sensor.

[0103] Therefore, the electronic device 1 according to one embodiment performs the following two stages of measurement and signal processing to calibrate a Doppler radar such as a millimeter-wave sensor. A. Measurement of the vibration of a reference oscillator B. Calibration of the electronic device 1 (millimeter-wave sensor) using the reference oscillator The electronic device 1 according to one embodiment measures the vibration of a vibrating body using a Doppler radar at a high frequency (20 GHz or higher) above the millimeter-wave band, which uses electromagnetic waves or sound waves to measure distance (ranging), estimate angle (angle measurement), and detect Doppler velocity. According to the electronic device 1 according to one embodiment, when measuring the vibration of a vibrating body using the Doppler radar described above, the absolute value of the vibration amplitude can be calibrated. By calibrating the millimeter-wave sensor, the electronic device 1 according to one embodiment can accurately measure the vibration amplitude of the vibrating body using the millimeter-wave sensor.

[0104] Hereinafter, each of the above-mentioned "A. Measurement of vibration of the reference oscillator" and "B. Calibration of the electronic device 1 (millimeter wave sensor) using the reference oscillator" will be further explained.

[0105] (A. Measurement of vibration of reference vibrator) Here, an electromechanical acoustic transducer capable of generating vibrations from several tens of Hz to 10 kHz or more, such as a loudspeaker, is used as the reference vibrator. The millimeter wave sensor detects the average vibration displacement by integrating all vibration components within the range irradiated by radio waves (Field of View (hereinafter referred to as FOV)). Therefore, here, it is necessary to obtain the average vibration displacement of the entire vibration surface for the electrical signal of the reference vibrator.

[0106] To obtain the average vibration displacement of the reference oscillator, it is possible to use LDV to perform measurements in one of the following ways: (1) Measure the vibration of one point on the reference oscillator, and obtain the vibration amplitude of the measurement point and the frequency response of the average displacement using a numerical analysis method such as the finite element method. (2) Scan the entire vibration surface of the reference oscillator.

[0107] The following will focus on the above (1), which is expected to be more realistically implemented.

[0108] In the above (1), it is important to know what frequency characteristics the ratio of the vibration displacement at the center (center of the dust cap) of a loudspeaker (diaphragm diameter approximately 10 cm) as shown in Figure 10 to the overall average vibration displacement has. It is not common to measure the vibration of the entire surface of a vibrating body such as a reference vibrator. Therefore, it is necessary to obtain the ratio of the vibration displacement to the overall average vibration displacement by analyzing the characteristics of the vibrating body in detail using numerical analysis or the like.

[0109] The ratio r(f ｉ ) is formulated as shown in the following equation (5).

[0110]

[0111] In the above formula (5), dcalc,point(f ｉ ) indicates the displacement frequency response of the center point of the reference oscillator. ｃａｌｃ，ｍｅａｎ (f ｉ ) indicates the average vibration displacement of the reference oscillator on the entire vibration plane. ｉdenotes the i-th discrete frequency.

[0112] FIG. 12 shows the relationship between r(f ｉ 12 shows an example of the results of calculating the ratio of the vibration displacement at the center position of a loudspeaker, which is a reference vibration body, to the average vibration displacement, using the finite element method. The horizontal axis of FIG. 12 represents frequency, and the vertical axis represents the displacement ratio.

[0113] The dashed line in FIG. 12 shows the relationship between r(f ｉ ) is shown. In an ideal piston diaphragm, the vibration displacement at a certain point and the average vibration are completely equal. Therefore, in an ideal piston diaphragm, it is natural that r(f ｉ ) is 1. In other words, in an ideal piston diaphragm, even if the vibration frequency changes, the average value over the entire surface does not change. Therefore, in an ideal piston diaphragm, r(f ｉ ) can be said to have no frequency dependence.

[0114] On the other hand, the solid line in FIG. 12 shows the r(f ｉ ) in a loudspeaker. ｉ ) has a frequency characteristic centered around 1. That is, in a loudspeaker, r(f ｉ ) is frequency dependent.

[0115] Next, the relationship between the size of the reference oscillator and the FOV determined by the directivity of the transmission and reception of waves will be described.

[0116] FIG. 13 is a diagram showing an example of the relationship between the size of the reference vibrator and the FOV determined by the directivity of wave transmission and reception. As shown in FIG. 13, vibrator 200 is the reference vibrator, which is a loudspeaker in this example. In FIG. 13, the FOV is a range determined by the direction estimation process already described as the directivity of wave transmission and reception and the received signal processing. In other words, the FOV is set so that vibrations within the range can be measured by the millimeter wave sensor. As shown in FIG. 13, by setting the FOV to include the entire reference vibrator, all vibrations of the reference vibrator are added together.

[0117] Next, an operation for generating data on the average vibration displacement of the reference oscillator for use in the electronic device 1 according to an embodiment will be described. Fig. 14 is a flowchart for explaining the generation of data on the average vibration displacement of the reference oscillator as a reference.

[0118] First, in step S11, one point on the reference oscillator is measured using an LDV or the like. In step S11, the frequency characteristic d of the vibration displacement at one measurement point is obtained by the measurement using the LDV or the like. ｒｅｆ，ｍｅａｓ， (f ｉ ) can be obtained.

[0119] Next, in step S12, it is determined whether or not the frequency i has reached the number of frequency points I. If the frequency i has not reached the number of frequency points I, the operation of step S11 is repeated to measure a plurality of frequencies. On the other hand, if the frequency i has reached the number of frequency points I, the operation of step S13 may be carried out. That is, in FIG. 14, the operation loop of step S11 is performed by measuring one point on the reference oscillator using an LDV or the like, and then measuring the frequency f ｉ This indicates that this should be done every time.

[0120] Next, in step S13, as described above, r(f ｉ ) is obtained. As mentioned above, r(f ｉ ) is the displacement frequency response dcalc,point(f ｉ ) and the average vibration displacement d of the reference vibration body on the entire vibration plane ｃａｌｃ，ｍｅａｎ (f ｉ ) (the above formula (5)).

[0121] Next, in step S14, d ｒｅｆ，ｍｅａｓ， (f ｉ ) and r(f ｉ ) and calculates the reference value of the average vibration displacement of the reference oscillator according to the following equation (6).

[0122]

[0123] d shown in the above formula (6) ｒｅｆ (f ｉ) is the data of the average vibration displacement of the reference oscillator obtained by the flowchart shown in FIG.

[0124] (B. Calibration of Electronic Device 1 (Millimeter Wave Sensor) Using Reference Vibration Body) Next, an operation of calibrating the electronic device 1 (millimeter wave sensor) using the reference vibration body will be described. Here, the electronic device 1 (millimeter wave sensor) according to one embodiment is calibrated in consideration of the frequency characteristics of the average vibration displacement of the entire vibration surface for the measured electrical signal of the reference vibration body.

[0125] 15 is a flowchart illustrating the operation performed by the electronic device 1 according to an embodiment. For example, FIG. 15 may be a flowchart illustrating the operation when calibrating each millimeter wave sensor unit. ｒｅｆ (f ｉ ) may be used as a flowchart for calibrating each individual millimeter-wave sensor.

[0126] 5 starts, in step S21, the signal processing unit 10 of the electronic device 1 according to an embodiment may calculate and store a calibration coefficient (ratio) between the measurement value of the reference vibrator by the electronic device 1 and the reference value. In step S21, the signal processing unit 10 may calculate and store the calibration coefficient (ratio) by comparing the measurement value of the reference vibrator by the electronic device 1 with the reference value. In step S21, the signal processing unit 10 calculates and stores the calibration coefficient (ratio) by comparing the measurement value of the reference vibrator by the electronic device 1 with the reference value. ｃａｌｉｂ (f ｉ ) can be calculated as follows:

[0127]

[0128] Here, the frequency response d of the vibration amplitude measured by the electronic device 1 (millimeter wave sensor) ｍｍｗａｖｅ (f ｉ ) is the time waveform q of the vibration amplitude measured by the electronic device 1 (millimeter wave sensor). ｍｍｗａｖｅ (t ｉ ) can be obtained by Fourier transform.

[0129] Next, in step S22, it is determined whether or not the frequency i has reached the number of frequency points I. If the frequency i has not reached the number of frequency points I, the operation of step S21 is repeated to calculate calibration coefficients for a plurality of frequencies. On the other hand, if the frequency i has reached the number of frequency points I, the operation shown in FIG. 15 may be ended. That is, in FIG. 15, the loop of the operation of step S21 is ｒｅｆ (f ｉ ) is used to show the process of performing calibration coefficients for each frequency.

[0130] The calibration coefficient (correction value) c obtained by the operation shown in FIG. ｃａｌｉｂ (f ｉ ) is a coefficient on the frequency axis. Therefore, the time waveform q mmwave,calib(t ｉ ) can be obtained as follows: In equation (8), F －１ [ ] denotes the inverse Fourier transform.

[0131]

[0132] The calibration coefficient (correction value) c obtained from FIG. 15 and the above equation (7) ｃａｌｉｂ (f ｉ ) may be stored in any memory of each electronic device 1 (each millimeter wave sensor system). As a result, each electronic device 1 (each millimeter wave sensor system) is automatically calibrated every time a measurement is performed. The correction process by the electronic device 1 according to the embodiment described above may be performed by, for example, the correction processing unit 13 in the signal processing unit 10 shown in FIG. 2 calculating the above formula (8).

[0133] Next, the results of calibration performed by the electronic device 1 according to an embodiment will be described. Fig. 16 is a graph showing an example of the results of calibration performed by the electronic device 1 according to an embodiment. In Fig. 16, the horizontal axis represents frequency, and the vertical axis represents vibration displacement.

[0134] 16 is a plot of the frequency characteristics of the average value of the vibration displacement over the entire surface of a vibrating body that is a loudspeaker, with the voltage value fixed. In one embodiment, the vibration displacement value output by the electronic device 1 (millimeter wave sensor) may be calibrated by acquiring a calibration value of the response of the electronic device 1 (millimeter wave sensor) for a reference vibrating body that serves as a reference.

[0135] The solid line in Figure 16 indicates the average value of vibration displacement calculated using a reference device (LDV) for the reference vibration body. The asterisk (*) plot in Figure 16 indicates raw data (before calibration) of the measurement results by electronic device 1 (millimeter wave sensor). The circle (o) plot in Figure 16 indicates the results of performing calibration on the raw data of the measurement results by electronic device 1 (millimeter wave sensor). As shown in Figure 16, the data after calibration (o) approaches the reference graph (solid line), indicating that the calibration was performed appropriately.

[0136] As described above, the control method of the electronic device 1 measures the vibration of the object (vibrating body 200) based on the electromagnetic waves reflected from the object, using the calibration information stored in the storage unit (calibration coefficient memory 14). The control method of the electronic device 1 includes a calibration step of calibrating the measurement result of the electronic device 1 based on the result of measuring the vibration of the reference vibrating body.

[0137] In the above-described calibration step, the measurement results of the electronic device 1 may be calibrated based on the results of measuring the vibration of the reference oscillator by a vibrometer (such as an LDV) different from the electronic device 1 .

[0138] The above-mentioned calibration step may include: a first calculation step of calculating, by numerical analysis, the ratio between the displacement frequency response of a specific point of the reference vibrator and the position-averaged frequency response averaged at the position of the displacement frequency response; a measurement step of measuring the specific point vibration, which is the vibration of a specific measurement point of the reference vibrator, using a reference inspection device (e.g., an LDV); and a second calculation step of calculating a reference for the average vibration displacement of the reference vibrator based on the above-mentioned ratio and the above-mentioned specific point vibration.

[0139] The calibration step may calibrate the measurement results of the electronic device 1 based on the average vibration displacement reference and the specific displacement frequency response of the reference vibration body measured by the electronic device 1 .

[0140] The above-described embodiment may be implemented as a program executed by an electronic device that measures vibrations of an object based on electromagnetic waves reflected from the object using calibration information stored in a storage unit. In this case, the program may execute a calibration step of calibrating the measurement results of the electronic device based on the results of measuring the vibrations of the reference oscillator.

[0141] The above-described embodiment may be implemented as an electronic device 1 according to one embodiment. In this case, the electronic device 1 may include a signal processing unit 10 and a correction processing unit 13. The signal processing unit 10 measures the vibration of an object based on electromagnetic waves reflected from the object, using calibration information stored in a storage unit (calibration coefficient memory 14). The correction processing unit 13 calibrates the measurement results of the electronic device 1 based on the results of measuring the vibration of the reference oscillator.

[0142] According to the electronic device 1 and the calibration method for the electronic device 1 of an embodiment, the millimeter wave sensor can be calibrated using another sensor that can detect vibrations more accurately. Therefore, according to the electronic device 1 and the calibration method for the electronic device 1 of an embodiment, the vibration of a vibrating body can be detected with high accuracy by transmitting and receiving waves such as millimeter waves. Therefore, the electronic device 1 and the calibration method for the electronic device 1 of an embodiment can be expected to be useful in a wide variety of fields.

[0143] (Other Embodiments) Hereinafter, other embodiments will be described.

[0144] 10, an example has been described in which vibration is measured using the vibrating body 200, which is an electrodynamic loudspeaker, as the reference vibrating body. However, in one embodiment, the vibrating body 200 used as the reference vibrating body may be a piezoelectric or electrostatic loudspeaker, or a vibrating body based on another principle may be used.

[0145] In the above-described embodiment, the reference vibrometer is an LDV. However, in one embodiment, the reference vibrometer may be, for example, a contact-type acceleration sensor.

[0146] 14 and 15 have been described assuming that the data for each frequency is changed in discrete steps. However, in one embodiment, processing and measurement may be performed by performing a frequency sweep to change the frequency continuously.

[0147] 10, an example has been described in which vibrations are measured using the vibrating body 200, which is an electrodynamic loudspeaker, as the reference vibrating body. However, in one embodiment, a vibrating body formed of a piezoelectric element and a metal plate may be used as the reference vibrating body.

[0148] FIG. 17 is a diagram schematically illustrating the appearance of a vibrating body composed of a piezoelectric element and a metal plate. As shown in FIG. 17 , the vibrating body 300 may include a piezoelectric element 310. Also, as shown in FIG. 17 , the vibrating body 300 may include fixed ends 320 at both ends to form a doubly supported beam. FIG. 18 is a diagram illustrating the vibration amplitude (vibration displacement) of the vibrating body 300 at 710 Hz. Furthermore, as a vibrating body usable as a reference vibrator in one embodiment, for example, a vibrating body having a cantilever structure or a doubly supported structure may be used. Furthermore, as a vibrating body usable as a reference vibrator in one embodiment, for example, a vibrating body made of a piezoelectric element and a metal such as aluminum, plastic, ceramic, wood, or other material, or a combination thereof may be used. Furthermore, as a resonant frequency of a vibrating body usable as a reference vibrator in one embodiment, one having a primary resonant frequency and a secondary resonant frequency may be used. In the present disclosure, the resonant frequency of a vibrating body usable as a reference vibrator in one embodiment may have a tertiary or higher resonant frequency.

[0149] A calibration method according to an embodiment can be used, for example, in the manufacturing process of the electronic device 1 (millimeter wave sensor). The calibration method according to an embodiment can be applied, for example, in the manufacturing process of the electronic device 1 (millimeter wave sensor), after manufacturing a substrate of the millimeter wave sensor (such as an antenna substrate or an electronic circuit mounted with an LSI) or after completing final assembly of the millimeter wave sensor. In this case, in one embodiment, the calibration coefficient (correction value) c ｃａｌｉｂ (f ｉ ) may be written to a non-volatile memory in the electronic device 1 (millimeter wave sensor) and / or an external device 60 ( FIG. 2 ) to which the electronic device 1 (millimeter wave sensor) is connected. The electronic device 1 or the control method for the electronic device 1 according to an embodiment may be implemented as a manufacturing method for the electronic device 1 in which the above-described calibration method is incorporated into the production process, for example.

[0150] While the present disclosure has been described based on various drawings and examples, it should be noted that those skilled in the art can easily make various modifications and alterations based on the present disclosure. Therefore, it should be noted that these modifications and alterations are within the scope of the present disclosure. For example, the functions included in each functional unit can be rearranged so as not to cause logical inconsistencies. Multiple functional units can be combined into one or divided. The above-described embodiments of the present disclosure are not limited to faithful implementation of each of the described embodiments, but can be implemented by combining each feature or omitting some features as appropriate. In other words, those skilled in the art can make various modifications and alterations to the contents of the present disclosure based on the present disclosure. Therefore, these modifications and alterations are within the scope of the present disclosure. For example, in each embodiment, each functional unit, each means, each step, etc. can be added to other embodiments so as not to cause logical inconsistencies, or can be replaced with each functional unit, each means, each step, etc. of other embodiments. Furthermore, in each embodiment, multiple functional units, each means, each step, etc. can be combined into one or divided into two or more. Furthermore, each of the above-described embodiments of the present disclosure is not limited to being implemented faithfully according to each of the described embodiments, but can also be implemented by combining each feature or omitting some of them as appropriate.

[0151] The above-described embodiment is not limited to implementation as the electronic device 1. For example, the above-described embodiment may be implemented as a control method for a device such as the electronic device 1. Furthermore, the above-described embodiment may be implemented as a program executed by a device such as the electronic device 1, or as a storage medium or recording medium on which a program is recorded.

[0152] The electronic device 1 according to the above-described embodiment has been described as including components constituting a so-called radar sensor, such as the transmitting antenna array 24 and the receiving antenna array 31. However, the electronic device according to the embodiment may be implemented as, for example, a configuration such as the signal processing unit 10. In this case, the signal processing unit 10 may be implemented as having a function of processing signals handled by the transmitting antenna array 24, the receiving antenna array 31, and the like.

[0153] REFERENCE SIGNS LIST 1 Electronic device 10 Signal processing unit 11 Signal generation processing unit 12 Received signal processing unit 13 Correction processing unit 14 Calibration coefficient (correction value) memory 14 Waveform analysis processing unit 21 Transmission DAC 22 Transmission circuit 23 Millimeter wave transmission circuit 24 Transmission antenna array 31 Reception antenna array 32 Mixer 33 Reception circuit 34 Reception ADC 50 Communication interface 60 External device

Claims

1. A method for controlling an electronic device that measures vibrations of an object based on electromagnetic waves reflected from the object using calibration information stored in a memory unit, the method comprising a calibration step of calibrating the measurement results of the electronic device based on the results of measuring the vibrations of a reference oscillator.

2. The control method according to claim 1, wherein the calibration step calibrates the measurement result of the electronic device based on the result of measuring the vibration of the reference vibrator by a vibrometer other than the electronic device.

3. The control method of claim 1, wherein the calibration step includes: a first calculation step of calculating, by numerical analysis, a ratio between the displacement frequency response of a specific point of the reference vibration body and a position average frequency response averaged at the position of the displacement frequency response; a measurement step of measuring a specific point vibration, which is the vibration of a specific measurement point of the reference vibration body, using a reference inspection device; and a second calculation step of calculating a reference for the average vibration displacement of the reference vibration body based on the ratio and the specific point vibration.

4. The control method according to claim 2, wherein the calibration step calibrates the measurement result of the electronic device based on the average vibration displacement reference and the specific displacement frequency response of the reference vibration body measured by the electronic device.

5. A program that causes an electronic device that measures the vibration of an object based on electromagnetic waves reflected from the object to execute a calibration step of calibrating the measurement results of the electronic device based on the results of measuring the vibration of a reference oscillator, using calibration information stored in a memory unit.

6. An electronic device comprising: a signal processing unit that measures vibrations of an object based on electromagnetic waves reflected from the object using calibration information stored in a memory unit; and a correction processing unit that calibrates the measurement results of the electronic device based on the results of measuring the vibrations of a reference oscillator.

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