Electronic apparatus, method for controlling electronic apparatus, and program

Abstract

To provide an electronic apparatus, a method for controlling an electronic apparatus, and a program that can detect a heartbeat of a human body or the like with good accuracy through transmission and reception of radio waves.SOLUTION: An electronic apparatus comprises: a transmitting antenna that transmits a transmission wave; a receiving antenna that receives a reflected wave that is the reflected transmission wave; and a signal processing unit that detects vibration caused by a heartbeat of a subject that reflects the transmission wave on the basis of a transmission signal transmitted as the transmission wave and a reception signal received as the reflected wave. The signal processing unit converts a signal based on the transmission signal and the reception signal into a first signal corresponding to the heart sound of the subject by using a method by first discrete wavelet conversion, uses a method by continuous wavelet transform for the first signal to output a scalogram for the first signal, extracts a value at a frequency taking the maximum value for the scalogram to make the scalogram into one dimension and outputs an envelope waveform of a heart sound waveform, and reconstructs the envelope waveform by using a method by second discrete wavelet conversion for the envelope waveform.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to an electronic device, a control method for an electronic device, and a program. [Background technology]

[0002] For example, in the field of the automobile industry, a technology for measuring the distance between a vehicle and a predetermined object is considered important. In particular, in recent years, various RADAR (Radio Detecting and Ranging) technologies have been researched, which transmit radio waves such as millimeter waves and receive the reflected waves from an object such as an obstacle to measure the distance between the vehicle and the object. The importance of such technology for measuring distance is expected to increase in the future with the development of technologies for assisting the driver in driving and technologies related to autonomous driving that automates part or all of driving.

[0003] Also, various proposals have been made regarding technologies for detecting the presence of a specific object by receiving a reflected wave of a transmitted radio wave reflected by the object. For example, Patent Document 1 proposes a device that can detect the presence of a person and the person's biological information by using microwaves. Also, for example, Patent Document 2 proposes a device that detects vital signs such as the breathing or heart rate frequency of a living body based on a reflected signal of a microwave radar. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2002-71825 A [Patent Document 2] Patent Publication No. 2021-32880 Summary of the Invention [Problem to be solved by the invention]

[0005] If it were possible to detect weak vibrations, such as those of the human heartbeat, with a high degree of accuracy by transmitting and receiving radio waves, such as millimeter waves, it is expected that this technology will be useful in a wide variety of fields.

[0006] 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 the heart rate of a human body or the like with high accuracy by transmitting and receiving radio waves. [Means for solving the problem]

[0007] The electronic device according to an embodiment includes: A transmitting antenna for transmitting a transmission wave; a receiving antenna for receiving a reflected wave of the transmission wave; a signal processing unit that detects vibrations caused by a heartbeat of an object reflecting the transmission wave based on a transmission signal transmitted as the transmission wave and a reception signal received as the reflected wave; Equipped with. The signal processing unit includes: converting the signal based on the transmitted signal and the received signal into a first signal corresponding to a heart sound of the subject by applying a first discrete wavelet transform technique; outputting a scalogram for the first signal by applying a continuous wavelet transform technique to the first signal; extracting a value at a frequency where the scalogram has a maximum value, converting the scalogram into a one-dimensional value, and outputting an envelope waveform of the phonocardiogram; The envelope waveform is reconstructed by applying a second discrete wavelet transform technique to the envelope waveform.

[0008] A method for controlling an electronic device according to an embodiment includes: A step of converting a signal based on a transmission signal transmitted as a transmission wave and a reception signal received as a reflected wave of the transmission wave into a first signal corresponding to the heart sound of the target by applying a first discrete wavelet transform technique to the signal; outputting a scalogram for the first signal by applying a continuous wavelet transform technique to the first signal; a step of extracting a value at a frequency where the scalogram has a maximum value, converting the scalogram into a one-dimensional value, and outputting an envelope waveform of the phonocardiogram; reconstructing the envelope waveform by applying a second discrete wavelet transform to the envelope waveform; Includes.

[0009] A program according to an embodiment includes: For electronic devices, A step of converting a signal based on a transmission signal transmitted as a transmission wave and a reception signal received as a reflected wave of the transmission wave into a first signal corresponding to the heart sound of the target by applying a first discrete wavelet transform technique to the signal; outputting a scalogram for the first signal by applying a continuous wavelet transform technique to the first signal; a step of extracting a value at a frequency where the scalogram has a maximum value, converting the scalogram into a one-dimensional value, and outputting an envelope waveform of the phonocardiogram; reconstructing the envelope waveform by applying a second discrete wavelet transform to the envelope waveform; Execute the command. Effect of the Invention

[0010] 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 the heart rate of a human body or the like with high accuracy by transmitting and receiving radio waves. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram illustrating a usage mode of an electronic device according to an embodiment. [Diagram 2] 1 is a functional block diagram illustrating a schematic configuration of an electronic device according to an embodiment. [Diagram 3] 1 is a diagram illustrating a configuration of a signal processed by an electronic device according to an embodiment. [Figure 4] FIG. 2 is a diagram illustrating signal processing by an electronic device according to an embodiment. [Diagram 5] FIG. 2 is a diagram illustrating signal processing by an electronic device according to an embodiment. [Figure 6] FIG. 2 is a diagram illustrating signal processing by an electronic device according to an embodiment. [Figure 7] 1A and 1B are diagrams illustrating an example of an antenna arrangement and an operation principle in an antenna array of an electronic device according to an embodiment. [Figure 8] 1 is a diagram illustrating an example of an arrangement of antennas in an antenna array of an electronic device according to an embodiment. [Figure 9] FIG. 2 is a diagram illustrating an example of signal processing by an electronic device according to an embodiment. [Figure 10] FIG. 2 is a diagram illustrating an example of signal processing by an electronic device according to an embodiment. [Figure 11] 10 is a flowchart illustrating a comparative example of the operation of the electronic device according to an embodiment. [Figure 12] 10 is a flowchart illustrating an operation of an electronic device according to an embodiment. [Figure 13] 10 is a flowchart illustrating an operation of an electronic device according to an embodiment. [Figure 14] FIG. 2 is a diagram illustrating an example of signal processing by an electronic device according to an embodiment. [Figure 15] FIG. 2 is a diagram illustrating an example of signal processing by an electronic device according to an embodiment. [Figure 16] FIG. 2 is a diagram illustrating an example of signal processing by an electronic device according to an embodiment. [Figure 17] FIG. 2 is a diagram illustrating an example of signal processing by an electronic device according to an embodiment. [Figure 18] FIG. 2 is a diagram illustrating an example of signal processing by an electronic device according to an embodiment. [Figure 19] FIG. 2 is a diagram illustrating an example of signal processing by an electronic device according to an embodiment. [Figure 20] FIG. 2 is a diagram illustrating an example of signal processing by an electronic device according to an embodiment. [Figure 21] FIG. 2 is a diagram illustrating an example of signal processing by an electronic device according to an embodiment. [Figure 22] FIG. 2 is a diagram illustrating an example of signal processing by an electronic device according to an embodiment. [Diagram 23] 1 is a diagram illustrating an example of an arrangement of antennas in an antenna array of an electronic device according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, one embodiment will be described in detail with reference to the drawings.

[0013] In the present disclosure, an "electronic device" may be a device that is powered by electricity. Furthermore, a "user" may be a person (typically a human) or an animal that uses a system and / or an electronic device according to an embodiment. A user may include a person who monitors a target such as a human by using an electronic device according to an embodiment. Furthermore, a "target" may be a person (e.g., a human or an animal) that is to be monitored by an electronic device according to an embodiment. Furthermore, a user may include a target.

[0014] The electronic device according to an embodiment can detect the heartbeat of a target such as a human being present around the electronic device. Therefore, the electronic device according to an embodiment can be used in specific facilities used by people who engage in social activities, such as companies, hospitals, nursing homes, schools, sports gyms, and nursing homes. For example, in a company, it is very important to understand and / or manage the health of employees. Similarly, in a hospital, it is very important to understand and / or manage the health of patients and medical professionals, and in a nursing home, it is very important to understand and / or manage the health of residents and staff. The electronic device according to an embodiment can be used in any facility where it is desired to understand and / or manage the health of a target, and is not limited to the above-mentioned facilities such as companies, hospitals, and nursing homes. The facility may include, for example, a non-commercial facility such as a user's home. The electronic device according to an embodiment can be used in any facility, not limited to indoors, but may be used outdoors. For example, the electronic device according to an embodiment can be used in a moving body such as a train, bus, or airplane, as well as in a station or a boarding area. 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, or the like.

[0015] The electronic device according to an embodiment may be used, for example, in a nursing facility or the like, for detecting or monitoring the heartbeat of a target such as a person requiring nursing care or a person requiring care. In addition, the electronic device according to an embodiment may issue a predetermined warning to the target and / or other people when an abnormality is found in the heartbeat of the target such as a person requiring nursing care or a person requiring care. Therefore, according to the electronic device according to an embodiment, for example, the target and / or staff of a nursing facility or the like may recognize that an abnormality is found in the pulse of a target such as a person requiring nursing care or a person requiring care. On the other hand, the electronic device according to an embodiment may notify the target and / or other people when an abnormality is not found (for example, recognized as normal) in the heartbeat of a target such as a person requiring nursing care or a person requiring care. Therefore, according to the electronic device according to an embodiment, for example, the target and / or staff of a nursing facility or the like may recognize that the pulse of a target such as a person requiring nursing care or a person requiring care is normal.

[0016] The electronic device according to an embodiment may detect the pulse of animals other than humans. The electronic device according to an embodiment described below will be described as detecting the pulse of a human using a sensor based on a technology such as millimeter wave radar, for example.

[0017] The electronic device according to an embodiment may be installed on any stationary object or any moving 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 or the like.

[0018] Hereinafter, as a typical example, the electronic device according to the embodiment will be described as being stationary. On the other hand, the subject (human) whose pulse is detected by the electronic device according to the embodiment may be stationary, may be moving, or may be moving its body while stationary. The electronic device according to the 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 normal radar sensor. Furthermore, the electronic device according to the embodiment can measure the distance between the electronic device and an object even when both the electronic device and the object are stationary.

[0019] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 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.

[0020] Fig. 1 is a diagram for explaining an example of a usage mode of an electronic device according to an embodiment. Fig. 1 shows an example of an electronic device having a function of a sensor and including a transmitting antenna and a receiving antenna according to an embodiment.

[0021] As shown in FIG. 1, the electronic device 1 according to an embodiment may include a transmitting unit and a receiving unit, which will be described later. As described later, the transmitting unit may include a transmitting antenna array 24. Also, the receiving unit may include a receiving antenna array 31. Specific configurations of the electronic device 1, the transmitting unit, and the receiving unit will be described later. For ease of viewing, FIG. 1 shows a state in which the electronic device 1 includes a transmitting antenna array 24 and a receiving antenna array 31. Also, the electronic device 1 may include at least one of the other functional units, such as at least a part of the signal processing unit 10 (FIG. 2) included in the electronic device 1, as appropriate. Also, the electronic device 1 may include at least one of the other functional units, such as at least a part of the signal processing unit 10 (FIG. 2) included in the electronic device 1, outside the electronic device 1. In FIG. 1, the electronic device 1 may be moving, or may be stationary without moving.

[0022] In the example shown in FIG. 1, the electronic device 1 is shown in a simplified form with a transmitter having a transmitting antenna array 24 and a receiver having a receiving antenna array 31. The electronic device 1 may include, for example, a plurality of transmitters and / or a plurality of receivers. The transmitter may include a transmitting antenna array 24 consisting of a plurality of transmitting antennas. Furthermore, the receiver may include a receiving antenna array 31 consisting of a plurality of receiving antennas. Here, the positions at which the transmitter and / or receiver are installed in the electronic device 1 are not limited to the positions shown in FIG. 1, and may be other positions as appropriate. Furthermore, the number of transmitters and / or receivers may be any number equal to or greater than one, depending on various conditions (or requirements) such as the range and / or accuracy of heartbeat detection by the electronic device 1.

[0023] As described below, the electronic device 1 transmits electromagnetic waves as transmission waves from the transmitting antenna array 24. For example, if a specific object (e.g., the target 200 shown in FIG. 1) is present around the electronic device 1, at least a part of the transmission wave 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, by the receiving antenna array 31 of the electronic device 1, the electronic device 1 can detect the object as a target.

[0024] The electronic device 1 equipped with 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, a LIDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging) technology using light waves. Such sensors may be configured to include, for example, a patch antenna. Since technologies such as RADAR and LIDAR are already known, detailed descriptions may be appropriately simplified or omitted. Furthermore, the electronic device 1 according to an embodiment may be a sensor based on a technology that detects an object by transmitting and receiving, for example, sound waves or ultrasonic waves.

[0025] The electronic device 1 shown in FIG. 1 receives, from the receiving antenna array 31, a reflected wave of a transmission wave transmitted from the transmitting antenna array 24. In this way, the electronic device 1 can detect a predetermined object 200 existing 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 a 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.

[0026] In Fig. 1, the XY plane may be, for example, a plane that is approximately 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 that is parallel to the XY plane. Also, in Fig. 1, the target 200 may be, for example, standing on the ground surface that is approximately parallel to the XY plane.

[0027] Here, the target 200 may be, for example, a human being present around the electronic device 1. The target 200 may also be a living thing other than a human being, such as an animal present around the electronic device 1. As described above, the target 200 may be moving, stopped, or stationary. In the present disclosure, the object detected by the electronic device 1 includes inanimate objects such as any object, as well as living things 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 by radar technology. In the following, the description will be given on the assumption that an object such as the target 200 present around the electronic device 1 is a human being (or an animal). Hereinafter, the "target 200" will also be referred to as the "subject 200" as appropriate.

[0028] 1, the ratio between the size of the electronic device 1 and the size of the target 200 does not necessarily indicate 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 of 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.

[0029] In the following, 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 (for example, around 20 GHz to 30 GHz). On the other hand, the transmitting antenna of the electronic device 1 may transmit radio waves having a frequency bandwidth of 4 GHz, for example, 77 GHz to 81 GHz.

[0030] 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.

[0031] When measuring distances and the like using a millimeter wave radar, a frequency modulated continuous wave radar (hereinafter, FMCW radar) is often used. In an FMCW radar, a transmission signal is generated by sweeping the frequency of radio waves to be transmitted. Therefore, in a millimeter wave FMCW radar using radio waves in a frequency band of, for example, 79 GHz, the frequency of the radio waves used has a frequency bandwidth of 4 GHz, such as 77 GHz to 81 GHz. A radar in the 79 GHz frequency band has a feature that the available frequency bandwidth is wider than other millimeter wave / quasi-millimeter wave radars in frequency bands of, for example, 24 GHz, 60 GHz, and 76 GHz. Hereinafter, such an embodiment will be described as an example.

[0032] The FMCW radar system used in the present disclosure may include an FCM (Fast-Chirp Modulation) system that transmits a chirp signal at a shorter period than normal. The signal generated by the electronic device 1 is not limited to an FMCW signal. The signal generated by the electronic device 1 may be a signal of various systems other than the FMCW system. The transmission signal sequence stored in an arbitrary storage unit may differ depending on these various systems. For example, in the case of the radar signal of the above-mentioned FMCW system, a signal whose frequency increases and decreases for each time sample may be used. Since the above-mentioned various systems can be appropriately applied using known technologies, a more detailed description will be omitted.

[0033] As shown in FIG. 2, the electronic device 1 according to the embodiment includes a signal processing unit 10. The signal processing unit 10 may include a signal generation processing unit 11, a reception signal processing unit 12, a heartbeat extraction unit 13, and a calculation unit 14. The heartbeat extraction unit 13 may execute, for example, a process of extracting a micro-Doppler component. The heartbeat extraction unit 13 may also execute a process of extracting an envelope of the heart sounds of the subject 200. The calculation unit 14 may execute, for example, a process of extracting the heartbeat interval (RRI) of the subject 200. The calculation unit 14 may also execute a process of performing a frequency analysis of the time series data of the extracted heartbeat interval of the subject 200. The calculation unit 14 may also execute a process of calculating the heartbeat variability of the subject 200 based on the frequency analysis of the time series data of the heartbeat interval. The signal generation processing unit 11, the reception signal processing unit 12, the heartbeat extraction unit 13, and the calculation unit 14 will be described further below as appropriate. In the present disclosure, the heart sound may be, for example, a chest vibration waveform (see FIG. 20, etc.) directly observed by a radar, or may be chest vibration. The heartbeat is the beating of the heart itself. The heartbeat interval, the heart rate, etc. may be calculated from the movement of the heartbeat.

[0034] Moreover, the electronic device 1 according to the embodiment includes a transmission DAC 21, a transmission circuit 22, a millimeter wave transmission circuit 23, and a transmission antenna array 24 as a transmission unit. Moreover, the electronic device 1 according to the embodiment includes a reception antenna array 31, a mixer 32, a reception circuit 33, and a reception ADC 34 as a reception unit. The electronic device 1 according to the embodiment may not include at least one of the functional units shown in FIG. 2, or may include a functional unit other than the functional unit shown in FIG. 2. The electronic device 1 shown in FIG. 2 may be configured using a circuit basically configured similarly to a general radar using electromagnetic waves such as a millimeter wave band. Meanwhile, in the electronic device 1 according to the embodiment, the signal processing by the signal processing unit 10 may include processing different from that of a conventional general radar.

[0035] The signal processing unit 10 included in the electronic device 1 according to an embodiment can control the operation of the entire 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 CPU (Central Processing Unit) or a DSP (Digital Signal Processor), to provide control and processing power for executing various functions. The signal processing unit 10 may be realized as one processor, several processors, or individual processors. The processor may be realized as a single integrated circuit. The integrated circuit is also called an IC (Integrated Circuit). The processor may be realized as a plurality of integrated circuits and discrete circuits connected to each other so as to be able to communicate with each other. The processor may be realized 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. The signal processing unit 10 may include a storage unit (memory) necessary for the operation of the signal processing unit 10 as appropriate.

[0036] The signal generation processing unit 11 of the signal processing unit 10 generates a signal to be transmitted from the electronic device 1. In the electronic device 1 according to an embodiment, 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 (linear chirp signal) whose frequency changes periodically and linearly. For example, the signal generation processing unit 11 may generate a chirp signal whose frequency increases periodically and linearly from 77 GHz to 81 GHz over time. Also, for example, the signal generation processing unit 11 may generate a signal whose frequency periodically repeats a linear increase (up chirp) and decrease (down chirp) from 77 GHz to 81 GHz over time. The signal generated by the signal generation processing unit 11 may be set in advance in, for example, the signal processing unit 10. Also, the signal generated by the signal generation processing unit 11 may be stored in advance in, for example, an arbitrary storage unit in the signal processing unit 10. Since chirp signals used in technical fields such as radar are known, a more detailed description will be appropriately simplified or omitted. The signal generated by the signal generating and processing unit 11 is supplied to the transmitting DAC 21. For this reason, the signal generating and processing unit 11 may be connected to the transmitting DAC 21.

[0037] The transmission DAC (digital-analog converter) 21 has a function of converting the digital signal supplied from the signal generating processing unit 11 into an analog signal. The transmission DAC 21 may be configured to include a general digital-analog converter. The signal converted into an analog signal 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.

[0038] The transmission circuit 22 has a function of converting the signal converted into an analog signal 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.

[0039] 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. Therefore, 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. Therefore, the millimeter wave transmission circuit 23 may also be connected to the mixer 32.

[0040] The transmitting antenna array 24 is an array of a plurality of transmitting antennas. In Fig. 2, the configuration of the transmitting antenna array 24 is shown in a simplified form. 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.

[0041] In this manner, the electronic device 1 according to the embodiment includes a transmitting antenna (the transmitting antenna array 24), and can transmit a transmitting signal (for example, a transmitting chirp signal) from the transmitting antenna array 24 as a transmitting wave.

[0042] 2, it is assumed that an object such as a subject 200 is present around the electronic device 1. In this case, at least a part of the transmission wave transmitted from the transmitting antenna array 24 is reflected by the object such as the subject 200. At least a part of the transmission wave transmitted from the transmitting antenna array 24 that is reflected by the object such as the subject 200 may be reflected toward the receiving antenna array 31.

[0043] The receiving antenna array 31 receives the reflected waves, which may be at least a portion of the transmitted waves transmitted from the transmitting antenna array 24 that are reflected by an object such as the subject 200.

[0044] 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 of the transmission 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 a reception signal received as a reflected wave to the mixer 32. For this reason, the receiving antenna array 31 may be connected to the mixer 32.

[0045] 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 typical millimeter wave radar. The mixer 32 supplies a signal generated as a result of the synthesis to the reception circuit 33. For this reason, the mixer 32 may be connected to the reception circuit 33.

[0046] 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.

[0047] The receiving ADC (analog-digital converter) 34 has a function of converting an analog signal supplied from the receiving circuit 33 into a digital signal. The receiving ADC 34 may be configured to include a general analog-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.

[0048] The reception signal processing unit 12 of the signal processing unit 10 has a function of performing various processes on the digital signal supplied from the reception DAC 34. For example, the reception signal processing unit 12 calculates the distance from the electronic device 1 to an object such as the subject 200 based on the digital signal supplied from the reception DAC 34 (distance measurement). The reception signal processing unit 12 also calculates the relative speed of the object such as the subject 200 with respect to the electronic device 1 based on the digital signal supplied from the reception DAC 34 (speed measurement). Furthermore, the reception signal processing unit 12 calculates the azimuth angle of the object such as the subject 200 as seen from the electronic device 1 based on the digital signal supplied from the reception DAC 34 (angle measurement). 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 transform (2D-FFT) in the range direction and the velocity direction, respectively. Thereafter, the reception signal processing unit 12 suppresses false alarms and makes the probability constant by removing noise points through processing such as UART (Universal Asynchronous Receiver Transmitter) and / or CFAR (Constant False Alarm Rate).The reception signal processing unit 12 then obtains the position of an object such as the subject 200 by estimating the arrival angle for points that satisfy the CFAR criteria. Information generated as a result of distance, speed, and angle measurement by the reception signal processing unit 12 may be supplied to the heart rate extraction unit 13.

[0049] The heartbeat extraction unit 13 extracts information related to the heartbeat from the information generated by the reception signal processing unit 12. The operation of extracting information related to the heartbeat by the heartbeat extraction unit 13 will be described further below. The information related to the heartbeat extracted by the heartbeat extraction unit 13 may be supplied to the calculation unit 14.

[0050] The calculation unit 14 performs various calculation processes and / or arithmetic processes on the information on the heartbeat supplied from the heartbeat extraction unit 13. The various calculation processes and / or arithmetic processes performed by the calculation unit 14 will be described further below. The various information calculated and / or processed by the calculation unit 14 may be supplied to, for example, a communication interface 50. For this reason, the calculation unit 14 and / or the signal processing unit 10 may be connected to the communication interface 50. The various information calculated and / or processed by the calculation unit 14 may be supplied to other functional units other than the communication interface 50.

[0051] The communication interface 50 includes 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, speed, and angle of an object such as the subject 200 to the external device 60 as, for example, a signal such as a CAN (Controller Area Network). For example, at least one of information regarding the position, speed, and angle of an object such as the subject 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 by wire or wirelessly via a communication interface 50. In an embodiment, the external device 60 may include any computer and / or any control device. Furthermore, the electronic device 1 according to an embodiment may be configured to include an external device 60. The external device 60 may have various configurations depending on how the information on the heartbeat and / or heart sounds 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 for explaining 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 the FCM (Fast-Chirp Modulation) method is used. 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 short intervals (for example, longer than the round-trip time between the electromagnetic 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 it into subframe units as shown in FIG. 3.

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

[0056] In the example shown in FIG. 3, several chirp signals such as c1, c2, c3, c4, ..., cn are included to form one subframe. That is, subframe 1 and subframe 2 shown in FIG. 3 are each configured to include 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 to form one frame (1 frame). That is, one frame shown in FIG. 3 is configured to include 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 configured to include N subframes, similar to frame 1. Also, a frame interval of a predetermined length may be included between the frames. One frame shown in FIG. 3 may be, for example, about 30 milliseconds 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 as an arbitrary number of frames. Also, some chirp signals are omitted in Fig. 3. In this manner, the relationship between the time and frequency of the transmission signal generated by the signal generation processing unit 11 may be stored 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 consisting of subframes including a plurality of chirp signals. Also, the electronic device 1 according to an embodiment may transmit a transmission signal consisting of a frame 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 an example, and for example, the chirp signal included in one subframe may be arbitrary. That is, in one embodiment, the signal generation processing unit 11 may generate a subframe including an arbitrary number (for example, an arbitrary multiple) of chirp signals. Also, the subframe structure as shown in FIG. 3 is an example, and for example, the subframe included in one frame may be arbitrary. That is, in one embodiment, the signal generation processing unit 11 may generate a frame including an arbitrary number (for example, an arbitrary multiple) of subframes. The signal generation processing unit 11 may generate signals of different frequencies. The signal generation processing unit 11 may generate a plurality of discrete signals having different bandwidths of frequency f.

[0060] Fig. 4 is a diagram showing, in another aspect, a part of the subframe shown in Fig. 3. Fig. 4 shows each sample of a received signal obtained by receiving the transmission signal shown in Fig. 3 as a result of performing 2D-FFT (Two Dimensional Fast Fourier Transform), which is processing performed in 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 represented by squares 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 in which a group of points on a range-Doppler (distance-velocity) plane is calculated 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. 2.

[0063] In FIG. 5, the horizontal direction represents range (distance) and the vertical direction represents velocity. The filled squares s1 shown in FIG. 5 represent point clouds indicating signals that exceed the CFAR threshold processing. The unfilled squares s2 shown 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 orientation from the radar calculated by direction estimation, and the position and velocity on a two-dimensional plane are calculated as a point cloud indicating an object such as the subject 200. Here, the direction estimation may be calculated by 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 result of the reception signal processing unit 12 converting the point cloud coordinates from the range-Doppler plane shown in Fig. 5 to the XY plane after performing direction estimation. As shown in Fig. 6, the reception signal processing unit 12 can plot the point cloud PG on the XY plane. Here, the point cloud PG is composed of each point P. Furthermore, each point P has an angle θ and a radial velocity Vr in polar coordinates.

[0065] The reception signal processing unit 12 detects an object present within the range where the transmission wave T is transmitted based on at least one of the results of the 2D-FFT and the angle estimation. The reception signal processing unit 12 may perform object detection by, for example, clustering processing based on the estimated distance information, speed information, and angle information. As an algorithm used for clustering data, for example, DBSCAN (Density-based spatial clustering of applications with noise) is known. 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, speed information, angle information, and power information of the object detected in the reception signal processing unit 12 may be supplied to an external device 60 or the like via a communication interface 50, for example.

[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 T. The receiving antenna array 31 receives a reflected wave R resulting from reflection of the transmission wave T. Then, the signal processing unit 10 detects an object (such as a subject 200) that reflects the transmission wave T based on the transmission signal transmitted as the transmission wave T and the reception signal received as the reflected wave R.

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

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

[0069] As shown in Fig. 7, the receiving antenna array 31 may be a linear arrangement of sensors such as receiving antennas. As shown in Fig. 7, in one embodiment, the receiving antenna array 31 may include a plurality of receiving antennas arranged in a linear arrangement. In Fig. 7, the receiving antenna array 31 includes antenna x 1 , x 2 , x 3 , …, x M A plurality of antennas such as these are indicated by small circles. The receiving antenna array 31 may be composed of any number of antennas. As shown in FIG. 7, the plurality of antennas constituting the receiving antenna array 31 are arranged at an interval of the array pitch d. A sensor array in which sensors (antennas, ultrasonic transducers, microphones, etc.) corresponding to various physical waves are arranged in an array in this manner is also called a Uniform Linear Array (ULA). As shown in FIG. 7, physical waves (electromagnetic waves, sound waves, etc.) are transmitted along a line having a wavelength of, for example, θ 1 and θ 2 Here, θ 1 and θ 2 may be the above-mentioned angle of arrival. 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 the sensors according to the direction of arrival of the physical wave. This method of estimating the direction of arrival of the wave is also referred to as angle of arrival estimation or direction of arrival (DoA).

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

[0071] Next, the 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 directions of arrival at two orthogonal angles.

[0073] As shown in FIG. 8, in the electronic device 1 according to an embodiment, the transmitting antenna array 24 and / or the receiving antenna array 31 may 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 a 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, each of the plurality of elements is spaced apart at an interval d shorter than half the wavelength λ of the transmission 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 arraying a plurality of patch antenna units in a direction 2 shown in the figure. The patch antenna units are spaced apart from each other by an interval d 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 a modified version of the arrangement of the 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 a plurality of elements electrically connected in the direction 2 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, each of the plurality of elements is spaced apart at an interval 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 arraying a plurality of patch antenna units in a direction 1 shown in the figure. The patch antenna units are spaced apart from each other by an interval d 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] All elements included in the transmitting antenna array 24 and the receiving antenna array 31 may 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 be arranged close to each other (monostatic). Furthermore, the direction 1 and the direction 2 shown in FIG. 8 may be geometrically orthogonal to each other.

[0079] The directivity of each of the transmitting antenna and the receiving antenna can be appropriately narrowed by the transmitting antenna array 24 and the receiving antenna array 31 as shown in FIG. 8. In addition, by using the transmitting antenna array 24 as shown in FIG. 8, the direction of transmission of each transmitting wave (transmitting signal) can be controlled at each timing of transmitting the transmitting wave, thereby realizing a beamformer for the direction 2 shown in FIG. 8. Furthermore, by using the receiving antenna array 31 as shown in FIG. 8, the arrival direction of the reflected wave can be estimated for the 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 showing an object such as the subject 200 in three dimensions.

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

[0081] The electronic device 1 according to an embodiment transmits a transmission wave such as a millimeter wave radar to the subject 200, and measures (estimates) the heartbeat of the subject 200 based on the result of receiving the reflected wave reflected at the chest where the heart of the subject 200 is located. As described above, the subject 200 may be a human or an animal. In this case, for example, a component assumed to be the envelope of the heartbeat can be extracted by frequency filtering the vibration at the position where the subject 200 is present, which is detected by the radar. Then, when the component assumed to be the envelope of the heartbeat is extracted, the interval between the peaks of the envelope is taken as the heartbeat interval, and an approximate heartbeat interval can be calculated. Here, an approximation can be used in which the peak of the heartbeat envelope roughly coincides with the R peak of the electrocardiogram. For this reason, the "heartbeat interval" is also written as the RR interval or RRI (RR interval), similar to the term used for the electrocardiogram.

[0082] Here, a method for estimating the heartbeat interval of subject 200 from the results of the above-mentioned 2D-FFT, CFAR processing, and arrival direction estimation will be considered. First, the appearance of a person's heartbeat or body movement will be described as a result of the 2D-FFT performed in Figs. 4 and 5.

[0083] FIG. 9 is a diagram showing an example of a result of receiving a reflected wave of a transmission wave transmitted to the subject 200 and performing 2D-FFT processing. FIG. 9 shows a spectrum showing the heart sound and body movement of the subject 200 as a result of 2D-FFT. In FIG. 9, the horizontal axis represents distance (Range) and the vertical axis represents velocity (Velocity). The signal processing unit 10 (e.g., heartbeat extraction unit 13) of the electronic device 1 according to an embodiment may extract, for example, a peak Hm as shown in FIG. 9 as a body movement such as the heartbeat of the subject 200. Here, the spectrum components shown by the peak Hm in FIG. 9 include not only the heart sound and the envelope of the heart sound of the subject 200 but also the body movement. In order to extract the heartbeat interval, it is necessary to extract the body movement, etc., so it is assumed that, for example, frequency filtering is performed. The frequency filtering performed here is assumed to be, for example, a band pass filter, a high pass filter, and / or a low pass filter for 0.5 Hz to 10 Hz.

[0084] FIG. 10 is a diagram for explaining a method of detecting a peak based on the envelope waveform of the heart sound obtained by the above-mentioned frequency filtering. The graph shown in FIG. 10 shows an example of a time change of the envelope waveform of the heart sound extracted by the above-mentioned frequency filtering. The envelope waveform shown in FIG. 10 includes many peaks as shown. Meanwhile, it is known that the heartbeat of the subject 200 falls within a range of about 50 to 130 times per minute. Therefore, by selecting a peak having a time interval of 0.4 seconds to 0.8 seconds, which is the reciprocal of the number of heartbeats per minute, from among the many peaks shown in FIG. 10, it is possible to calculate an approximate heart sound interval of the subject 200. For example, the peak indicated by the downward arrow in FIG. 10 may be selected as the approximate heart sound interval of the subject 200.

[0085] 11 is a flowchart showing an example of the above-mentioned operation of estimating a heartbeat interval. Hereinafter, the above-mentioned operation of estimating a heartbeat interval will be outlined with reference to FIG.

[0086] Fig. 11 shows the operation of the electronic device 1 according to one embodiment after receiving a reflected wave. That is, as a premise for the operation shown in Fig. 11, the electronic device 1 shown in Fig. 2 transmits a transmission wave (transmission signal) from the transmitting antenna array 24. Then, at least a part of the transmission wave transmitted from the electronic device 1 is reflected by the subject 200 (the chest of the subject) and becomes a reflected wave. Then, the electronic device 1 shown in Fig. 2 receives such a reflected wave from the receiving antenna array 31. Then, the operation shown in Fig. 11 starts.

[0087] 11 starts, first, in step S110, the signal processing unit 10 of the electronic device 1 processes a received signal (received signal). The signal processing performed in step S110 may include, for example, the above-mentioned 2D-FFT, CFAR processing, and / or arrival direction estimation. Such an operation may be performed, for example, by the received signal processing unit 12 of the signal processing unit 10.

[0088] Next, in step S120, the signal processing unit 10 extracts a vibration source from the information processed in step S110. The signal processing performed in step S120 may include, for example, a process of filtering data resulting from 2D-FFT processing. In step S120, the signal processing unit 10 may extract spectral components only at the position where the subject 200 is present. Here, the position where the subject 200 is present may be specified by various known methods. Such an operation may be performed, for example, by the heart rate extraction unit 13 of the signal processing unit 10.

[0089] Next, in step S130, the signal processing unit 10 converts the result of the previous processing into a vibration waveform. The processing performed in step S130 may include, for example, a process of extracting phase information from the IQ data. In step S130, the signal processing unit 10 may include a process of extracting vibration data including heart sounds from the spectral components of the 2D-FFT processing of the subject 200 extracted in step S120. Such an operation may be performed by, for example, the heartbeat extraction unit 13 of the signal processing unit 10.

[0090] Next, in step S140, the signal processing unit 10 extracts vibration data from the result of the previous processing. The processing performed in step S140 may include, for example, frequency filtering. In step S140, the signal processing unit 10 may extract a low-frequency signal including an envelope of the heart sounds of the subject 200 by performing frequency filtering. Such an operation may be performed, for example, by the heartbeat extraction unit 13 of the signal processing unit 10.

[0091] Next, in step S150, the signal processing unit 10 detects the peak of the heartbeat of the subject 200 from the result of the previous processing. In step S150, the signal processing unit 10 may detect the peak of a low-frequency signal including an envelope of the heart sound of the subject 200. Such an operation may be performed by, for example, the calculation unit 14 of the signal processing unit 10.

[0092] Next, in step S160, the signal processing unit 10 calculates the RR interval (RRI) of the subject 200 from the results of the previous processing. In step S160, the signal processing unit 10 may calculate the interval between each peak. In step S160, the signal processing unit 10 may calculate the RRI by extracting the interval between the peak values ​​detected in step S150. Such an operation may be performed by, for example, the calculation unit 14 of the signal processing unit 10.

[0093] Next, in step S170, the signal processing unit 10 analyzes the spectrum from the result of the previous processing. In step S170, the signal processing unit 10 may calculate the heart rate variability (HRV) of the subject 200 by calculating the spectral density of the time series data of the RRI. When calculating the power spectral density of the time series data of the RRI, for example, the Welch method or the like may be used. Such an operation may be performed by, for example, the calculation unit 14 of the signal processing unit 10.

[0094] As described above, the electronic device 1 according to an embodiment extracts a component that is thought to be the envelope of the heartbeat by frequency filtering the vibration at the position where the subject 200 is present, and determines the interval between the peaks of the envelope as the heartbeat interval. In this way, the electronic device 1 according to an embodiment can calculate the approximate heartbeat interval of the subject 200.

[0095] In the calculation of the heartbeat interval as described above, for example, as shown in FIG. 10, several peaks are present within a time period of several tens of milliseconds. Therefore, a certain degree of uncertainty is involved in the selection of the heartbeat peak. For this reason, the accuracy of the calculated heartbeat interval also has an error of several tens of milliseconds. For example, in the calculation of the heartbeat interval as described above, an error of at least about 20 ms occurs when compared with the instantaneous RRI obtained by an electrocardiograph. With this accuracy, it is difficult to calculate heart rate variability (HRV) and perform a person's autonomic nerve and / or emotion analysis. That is, in the calculation of the heartbeat interval as described above, it is difficult to perform a more advanced medical analysis by extracting heart sounds.

[0096] Therefore, it is conceivable to further cut the peaks on the high frequency side by frequency filtering so that the time interval between heartbeats becomes about 0.4 to 0.8 seconds. However, since the accuracy of the signal information shown in Fig. 10 is not exceeded, it seems difficult to reduce the error of about several tens of milliseconds.

[0097] In addition, the heart sounds are not extracted in the calculation of the heartbeat intervals described above. Therefore, it is difficult to obtain information that contributes to diagnosis (e.g., auscultation in medical treatment) based on the acoustic properties of the heart sounds themselves using the above-mentioned method.

[0098] Therefore, the electronic device 1 according to an embodiment further improves on the above-mentioned method. As a result, the electronic device 1 according to an embodiment extracts the heart sounds using a radar using a high frequency band of, for example, millimeter waves or higher, and analyzes the heart sounds themselves to extract accurate heartbeat intervals. Such a method will be described below.

[0099] In order to extract the heart sounds of the subject 200 with high accuracy, the electronic device 1 according to an embodiment performs appropriate signal processing on the signal (chirp signal) received by the electronic device 1 in an appropriate order to narrow down the subspace and subspace base in which the signal components of the heart sounds of the subject 200 exist. The electronic device 1 according to an embodiment may employ different basis vectors in the linear space in which the signal of the heart sounds of the subject 200 exists, and extract the subspace based on the respective coordinates while describing the space using an appropriate coordinate system. By such processing, the electronic device 1 according to an embodiment can search for the subspace in which the heart sounds of the subject 200 exist. In an embodiment, such a coordinate system may be an appropriate one depending on the purpose. For example, a coordinate system such as a coordinate system of a space subjected to 2D-FFT processing, a coordinate system of a time series signal obtained by temporally contracting a chirp signal, a coordinate system by the Fourier transform thereof, or a coordinate system by continuous / discrete wavelet may be used.

[0100] The electronic device 1 according to an embodiment may execute the following characteristic processes for a received signal in a step-by-step procedure. The characteristic processes performed by the electronic device 1 according to an embodiment will be outlined below in order.

[0101] Stage 1: Dimensionality reduction In the first stage, an appropriate window function is applied to the 2D-FFT processing of the received chirp signal, and only the micro-Doppler components of the point cloud where the subject 200 is present are extracted by estimating the direction of arrival.

[0102] Second stage: Reducing the subspace dimension In the second stage, the micro-Doppler signals are subjected to principal component analysis and / or singular value decomposition of the set of vibration time-series waveforms extracted in the processing of the first stage.

[0103] Third stage: Subspace dimensionality reduction In the third stage, frequency filtering is performed by using at least one of a short-time Fourier transform, a continuous wavelet transform, and a band-pass filter.

[0104] Fourth stage: Subspace dimensionality reduction In the fourth step, the heart sounds are extracted by performing multi-resolution analysis using discrete wavelet transform with wavelet and scaling functions appropriate for the heart sounds.

[0105] According to the electronic device 1 of the embodiment, the envelope waveform of the heart sound obtained through the above-mentioned processing steps is obtained, and the positive and negative peaks are detected and the interval between them is appropriately calculated, so that the RRI can be calculated with high accuracy. Here, as a method for obtaining the envelope waveform, for example, calculation of the envelope waveform by the continuous wavelet transform or the Hilbert transform may be applied.

[0106] Next, the operation of the electronic device 1 according to the embodiment will be described in more detail.

[0107] Fig. 12 is a flowchart showing an example of the operation performed by the electronic device 1 according to an embodiment. Fig. 13 is a flowchart showing in more detail an example of the operation of step S15 in Fig. 12. Hereinafter, the flow of the operation performed by the electronic device 1 according to an embodiment will be roughly described with reference to Figs. 12 and 13.

[0108] Step S11 shown in Fig. 12 can be performed in the same manner as the operation in step S110 shown in Fig. 11. That is, when the operation shown in Fig. 12 starts, first, in step S11, the signal processing unit 10 of the electronic device 1 processes a received signal (received signal). The signal processing performed in step S11 may include, for example, the above-mentioned 2D-FFT, CFAR processing, and / or arrival direction estimation. Such an operation may be performed, for example, by the received signal processing unit 12 of the signal processing unit 10.

[0109] Next, in step S12, the signal processing unit 10 extracts the vibration source from the information processed in step S11. However, the extraction of the vibration source performed in step S12 may be a process different from the extraction of the vibration source performed in step S120 shown in Fig. 11. In step S12, the signal processing unit 10 may extract only the region in which the subject 200 exists on the range-Doppler plane calculated by 2D-FFT using an appropriate window function. In step S12, the signal processing unit 10 may use a window function such as a Hanning window, a Hamming window, or a Blackman-Harris window.

[0110] In step S12, the signal processing unit 10 may extract a vibration source including heart sounds and / or body movements including breathing of the subject 200, for example, based on the following procedure.

[0111] (Step 1) The signal processing unit 10 classifies the points exceeding the CFAR threshold on the range-Doppler plane into areas of a predetermined angle based on the result of the direction of arrival estimation (see Fig. 5 and Fig. 6). For example, if the angle on the xy plane shown in Fig. 6 is θ, the points may be classified into areas A to C of the following angles. Area A: -10deg.<θ<10deg. Area B: -20deg.<θ≦-10deg. Area C: 10deg.≦θ<20deg.

[0112] (Second step) The signal processing unit 10 applies clustering to a group of points that exceed a CFAR threshold on a range-Doppler plane such as S1 in Fig. 5, within a group of areas of a certain angle classified in the first step. Here, a method such as DBSCAN may be applied as the clustering method.

[0113] (Third Step) The signal processing unit 10 calculates the deviation D of the number of bins in the Doppler direction for the l-th cluster assuming that L clusters have been processed in the second step. dev Let [l] be a formula value D dev,th As a result of this comparison, the signal processor 10 compares the dev [l]≧D dev,th Only those who satisfy the condition are determined to be the subject 200, and a flag HF[l] is set. That is, the signal processing unit 10 may perform the following process using pseudo code, for example. for l = 1 to L do if D dev [l] ≧ D dev,th HF[l] = 1 else HF[l] = 0 end if end do

[0114] The signal processing unit 10 may perform subsequent processing only on the region of the cluster where the flag HF[l] of the subject 200 is 1. The signal processing unit 10 applies a window function centered on the central bin in the range direction to the cluster at number l where HF[l]=1. This allows the signal processing unit 10 to extract vibrations including heart sounds, breathing, and / or body movements of the subject 200. The above operations may be performed by, for example, the received signal processing unit 12 or the heartbeat extraction unit 13 of the signal processing unit 10.

[0115] Next, in step S13, the signal processing unit 10 extracts vibration elements from the information of the vibration source extracted in step S12. In step S13, the signal processing unit 10 performs singular value decomposition (SVD) to pre-process and remove noise from the signal. In step S13, the signal processing unit 10 may remove low-energy noise. Also, in step S13, the signal processing unit 10 may remove vibration data that has been mixed in due to the uncertainty of the Fourier transform (vibration data other than that at the desired position as shown in FIG. 9). The above operations may be performed, for example, by the received signal processing unit 12 or the heartbeat extraction unit 13 of the signal processing unit 10.

[0116] The next step S14 can be performed in the same manner as the operation in step S130 shown in Fig. 11. That is, in step S14, the signal processing unit 10 converts the result of the previous processing into a vibration waveform. The processing performed in step S14 may include, for example, a process of extracting phase information from the IQ data. Such an operation may be performed by, for example, the received signal processing unit 12 or the heartbeat extraction unit 13 of the signal processing unit 10.

[0117] The processes performed in steps S13 and S14 will now be described in further detail.

[0118] Here, the received chirp signal set extracted in the 2D-FFT plane is denoted as S vib S vib By performing singular value decomposition, we obtain the result shown in the following equation (1).

number

[0119] In equation (1), the matrix of left singular vectors is denoted as U, the matrix in which singular values ​​are arranged diagonally is denoted as Σ, and the matrix in which right singular vectors are arranged is denoted as V. In equation (1), * denotes Hermite transpose. Furthermore, N denotes the number of samples in one chirp signal, and M denotes the number of snapshots of the chirp.

[0120] Next, we restrict the number of row vectors in the left singular vector row of the above formula (1) (U ext ) and limit the number of diagonal elements of the diagonal matrix of singular values ​​(Σ ext ) This eliminates unnecessary noise signals and vibration components other than the desired position. As a result, S vib The signal S projected onto the subspace of the target signal ext is expressed as the following equation (2).

number

[0121] FIG. 14 is a diagram illustrating the relationship between the ranks of the target signal and the noise signal in the singular value decomposition. ext By taking the total number of samples N in one chirp signal, or the sum of some samples, we obtain the signal p as shown in the following equation (3). ext Generate the signal p ext represents micro-Doppler. FIG. 14 is a diagram in which the results of SVD are arranged in descending order of singular value (corresponding to energy), with the horizontal axis representing rank and the vertical axis representing singular value. In the present disclosure, the idea is adopted that a signal that is equal to or greater than a certain singular value becomes a target signal. In this case, the rank of the singular value that is the boundary between whether it is a target signal or not is the rank region of 30 or less, which is indicated by the dark gray part in the graph of FIG. 14. As shown in FIG. 14, the rank region of 30 or less is the region of the target signal. In FIG. 14, the rank portion of this target signal is 1 or more and 30 or less. Therefore, in the present disclosure, singular vectors corresponding to the left and right singular values ​​of the rank region of 1 or more and 30 or less are extracted.

[0122] In the above example, the rank portion of the target signal is 1 or more and 30 or less. The maximum rank may basically be determined empirically. The maximum rank (rank 30 in this disclosure) may also be determined by a statistical method. In the graph of FIG. 14, the singular value suddenly decreases at rank 130, and signals with ranks after that are basically noise. For this reason, the rank signals after that may be unnecessary.

[0123] In the graph of Fig. 14, the left and right singular vectors (vectors spanning the signal space) corresponding to the singular values ​​in the rank 31 to 130 area also contain some target signal components. It is assumed that the main causes of these left and right singular vectors are unnecessary minute vibrations and / or artificial noise (artifacts) generated by radar signal processing. Therefore, such elements may be discarded.

number

[0124] Complex signal (I / Q signal) p ext Vibration displacement d that can take the phase of ext can be expressed as the following equation (4).

number

[0125] The vibration displacement d shown in the above formula (4) ext By taking the time derivative of the vibration velocity v ext can be calculated.

number

[0126] Next, in step S15 shown in Fig. 12, the signal processing unit 10 extracts heart sounds, RRI, and / or HRV from the processing result in step S14. Step S15 includes several signal processing steps. The signal processing steps performed in step S15 in Fig. 12 are shown in more detail in the flowchart of Fig. 13. The operation or processing shown in Fig. 13 may be executed by, for example, the calculation unit 14 in the signal processing unit 10. The operation or processing shown in Fig. 13 will be further described below.

[0127] When the operation of step S15 shown in Fig. 12, i.e., the operation shown in Fig. 13, starts, in step S21, the signal processing unit 10 performs a process of removing noise (denoising). Various methods may be adopted for the denoising process performed in step S21. For example, in step S21, the signal processing unit 10 may perform a process of denoising a time series waveform using, for example, an empirical Bayes method or a wavelet method.

[0128] Next, in step S22, the signal processing unit 10 extracts a target signal waveform (cardiac sound waveform) by using a discrete wavelet technique (maximum overlap discrete wavelet transform: MODWT) or the like.

[0129] The processes performed in step S21 and / or step S22 will be further described.

[0130] In step S21, the signal processing unit 10 calculates the signal velocity vector v ext Further pre-processing is performed to remove unnecessary noise.

[0131] In step S21, the signal processing unit 10 may perform denoising by limiting the band using an empirical Bayes method and / or a continuous wavelet. In addition, in step S21, the signal processing unit 10 may perform denoising by frequency subtraction using a noise profile for artifact noise and the like accompanying the nonlinear processing from step S11 to step S14 in FIG. 12.

[0132] The signal processing unit 10 may perform multi-resolution analysis by discrete wavelet transform on the denoised signal as pre-processing, employing a wavelet waveform having a waveform similar to the heart sound waveform. In this way, in step S22, the signal processing unit 10 empirically extracts only a subspace of the level of multi-resolution analysis in which the heart sound of the subject 200 exists. In this way, in step S22, the signal processing unit 10 may extract the heart sound of the subject 200. Specifically, the signal processing unit 10 may use maximal overlap multi-resolution analysis (MODWT) or the like to improve the temporal resolution. In addition, the wavelet base suitable for extracting the heartbeat may be, for example, Symlet and Daubechies. In addition, these orders may be appropriately set each time.

[0133] The denoising process in step S21 is performed on the signal velocity vector v ext The signal sent to v dn and this real part Re(v dn ) may be subjected to a multi-resolution analysis as shown in FIG. 15. FIG. 15 is a conceptual diagram showing a multi-resolution analysis using a discrete wavelet transform. The signal processing unit 10 then determines an empirically appropriate level by multiplying j in the following equation (6). 0 By restricting the reconstructed waveform to ∈N, the heart sound waveform h can be obtained.

number

[0134] The heart sound waveform h obtained by the above formula (6) shows the heart sounds of the subject 200 with high accuracy (see Figs. 19 and 20 described later). This result is expected to be accurate enough to be used directly in heart sound diagnosis and the like.

[0135] Next, in step S23, the signal processing unit 10 detects the peak of the heart sound in the scalogram. The signal processing unit 10 detects the power (level) of the peak at each time point. Here, the time point at which the heart sound is located is detected as the position of the peak. In step S23, the signal processing unit 10 detects (extracts) a peak in the energy of the target signal (heart sound waveform) extracted in step S22. To this end, the signal processing unit 10 extracts a scalogram by continuous wavelet transform and an envelope waveform by converting it into a one-dimensional form.

[0136] More specifically, the signal processor 10 obtains a scalogram by continuous wavelet transform in order to obtain an envelope waveform of the cardiac sound waveform h. The signal processor 10 obtains a one-dimensional waveform by taking the maximum value in the frequency axis direction at each time point of the scalogram.

[0137] Fig. 16 and Fig. 17 are diagrams for explaining multi-resolution analysis using discrete wavelet transform. Fig. 16 is a diagram showing an example of a scalogram of a heart sound waveform h. Fig. 17 is a diagram showing an example of the scalogram of the heart sound waveform h shown in Fig. 16 made one-dimensional.

[0138] Let S be the matrix showing the absolute value of the scalogram shown in Fig. 16. h ∈R M×L Then, the one-dimensional waveform as shown in FIG. 17 can be calculated by the for statement as shown in the following equations (7) to (9). for m = 1:M (7)

number

[0139] Next, in step S24, the signal processing unit 10 controls the roughness of the peaks of the scalogram. In step S24, the signal processing unit 10 further removes high frequency components in an appropriate range in order to properly calculate the peaks of the envelope waveform of the heart sounds extracted in step S23. For this reason, the signal processing unit 10 may adjust the smoothness of the envelope by a discrete wavelet transform using a Haar wavelet or the like.

[0140] The signal processor 10 calculates the vector s h In order to further adjust the smoothness appropriately, the signal may be reconstructed using multi-resolution analysis by discrete wavelet transform. A suitable wavelet base to be used here may be the Haar wavelet or the like. The concept of multi-resolution decomposition may be the same as that shown in FIG. 15, for example. The reconstruction equation of the multi-resolution decomposition may be the same as that shown in the above equation (6). The vector s obtained in this way as the envelope waveform of the heart sound is h The reconstructed version of h,rc It is written as follows.

[0141] Next, in step S25, the signal processing unit 10 identifies the positions of the first heart sound and the second heart sound clarified by the processing up to step S25. In step S25, the signal processing unit 10 may pick up the first heart sound S1 and the second heart sound S2 in the heart sounds and pair the first heart sound S1 and the second heart sound S2.

[0142] For example, as shown in Fig. 17, the vector s h,rchas a degree of accuracy sufficient to clearly indicate the first and second heart sounds. Therefore, in step S25, the signal processor 10 may perform pairing of the first heart sound S1 and the second heart sound S2 to accurately measure the interval between the first heart sounds S1. When performing the pairing as described above, the signal processor 10 first performs h,rc Peak detection may be performed on all peaks in

[0143] 18 is a diagram showing an example of peak detection of a heartbeat envelope waveform. The signal processing unit 10 executes peak detection as shown in FIG. 18 to obtain a row vector l s1,s2 ∈R K Here, we can create a row vector l s1,s2 A case where DBSCAN, a clustering algorithm, is used for the above will be described. The signal processing unit 10 sets minPts (the minimum number of adjacent data points other than the own data point) which is a parameter of DBACAN, to 1. The signal processing unit 10 also measures ε (the distance between adjacent data points) which is a parameter of DBACAN, in terms of time. In this way, the signal processing unit 10 sets the value measured in terms of time to a standard time interval between the first heart sound S1 and the second heart sound S2, which is about 0.2 to 0.4 seconds.

[0144] By this process, a pair of the first heart sound S1 and the second heart sound S2 is determined. s1,s2 Add a second row to the list matrix L, assign the row cluster number (pair number 1 or more) to the first heart sound S1, and assign the value 0 to the second heart sound S2. s1,s2 In this way, the signal processing unit 10 creates a list matrix L s1,s2 In the row vector l, the first heart sound S1 can be clearly identified and its order can also be clearly shown. s1,s2 or list matrix L s1,s2 In the case where S1 is not paired, the signal processing unit 10 may list the unpaired peak as S1.

[0145] Next, in step S26, the signal processing unit 10 calculates the heartbeat interval RRI. In step S26, the signal processing unit 10 may calculate the RRI by calculating the interval between the first peaks paired in step S25, i.e., between the first heart sounds S1.

[0146] The signal processing unit 10 calculates a list matrix L s1,s2 In the above, the RRI is calculated by taking the interval between adjacent S1. Here, it is assumed that outliers may occur in the calculated RRI time series data. Such outliers may occur, for example, due to non-detection of the first heart sound S1, confusion between the first heart sound S1 and the second heart sound S2, or due to noise caused by large body movements. Therefore, in one embodiment, the signal processing unit 10 may perform a correction process to deal with the above-mentioned situations.

[0147] In step S26, the signal processing unit 10 may use a Bayesian estimation method such as a Kalman filter as a correction process. The heartbeat response is nonlinear, and it is difficult to physically model the plant. For this reason, in step S26, the signal processing unit 10 may perform a correction process based on a statistical method such as an Unscented Kalman Filter (UKF). On the other hand, a linear Kalman Filter may be used approximately, or an Extended Kalman Filter (EKF) may be used by modeling the transition of the heartbeat interval in empirical modeling.

[0148] The data obtained in step S26 is the RRI time series data s RRI It is acceptable to do so.

[0149] Next, in step S27, the signal processing unit 10 analyzes the spectrum. In step S27, the signal processing unit 10 may calculate a spectrogram of the RRI (HRV). In step S27, the signal processing unit 10 may calculate the power spectral density of the time series data of the RRI by, for example, the Welch method. The signal processing unit 10 finally calculates s RRIThe FFT and power spectrum may be calculated according to the Welch method, i.e., by using window functions that overlap in time. By such processing, the signal processing unit 10 can obtain the power spectrum density of the RRI (see FIG. 22 described later).

[0150] Fig. 19 is a diagram showing a time-series waveform of a heart sound obtained by the electronic device 1 according to an embodiment. Fig. 19 may show a heart sound waveform h obtained by the above formula (6). Fig. 20 is a diagram showing an enlarged time span of the region surrounded by a dashed line in Fig. 19.

[0151] As shown in Fig. 20, the first heart sound S1 and the second heart sound S2 can be clearly identified from the time series waveform of the heart sounds obtained by the electronic device 1 according to an embodiment. Also, as shown in Fig. 20, the heart beat interval RRI calculated from the interval between the first heart sound S1 and the second heart sound S2 can be clearly identified from the time series waveform of the heart sounds obtained by the electronic device 1 according to an embodiment. Here, the RRI and the heart beat interval are not exactly the same, but are considered to be approximately the same. For this reason, in the present disclosure, the RRI and the heart beat interval will be described as being the same thing.

[0152] Fig. 21 is a diagram showing an example of the time-series waveform of the RRI shown in Fig. 19 and Fig. 20. The result shown in Fig. 21 is calculated based on the heart sounds accurately extracted in Fig. 19 and Fig. 20. Therefore, the result shown in Fig. 21 has an accuracy of several ms.

[0153] Fig. 22 is a diagram showing the power spectral density of the RRI. Fig. 22 is a diagram showing an example of the power spectral density calculated from the time series waveform of the RRI shown in Fig. 21 using the Welch method. According to the electronic device 1 of an embodiment, it is possible to calculate the power spectral density of the RRI based on the RRI with an accuracy of several ms. Therefore, according to the electronic device 1 of an embodiment, it is possible to accurately calculate the component of the heartbeat PSD from 0.15 Hz to 0.4 Hz, which is called the HF.

[0154] As described above, the electronic device 1 according to an embodiment can obtain detailed heart sound waveforms as shown in Figs. 19 and 20, accurate RRI time series data as shown in Fig. 21, and power spectral density (PSD) of heartbeat intervals as shown in Fig. 22. The electronic device 1 according to an embodiment can detect the heartbeat of a human body or the like with good accuracy by transmitting and receiving radio waves. Therefore, the electronic device 1 according to an embodiment can detect weak vibrations such as the heartbeat of a human body or the like with good accuracy by transmitting and receiving radio waves such as millimeter waves, and is expected to be useful in a wide variety of fields.

[0155] 19 to 22, only the first heart sound S1 and the second heart sound S2 that are prominent in healthy people are described. However, according to the electronic device 1 according to one embodiment, even when the third and / or fourth heart sound occurs due to an abnormality in the heartbeat, it can be processed in the same manner.

[0156] (Other embodiments) Other embodiments will be described below.

[0157] In one embodiment, the transmitting antenna array 24 and / or the receiving antenna array 31 included in the electronic device 1 are not limited to the arrangement shown in Fig. 8. For example, in one embodiment, the receiving antenna array 31 included in the electronic device 1 may be configured as shown in Fig. 23. Fig. 23 is a diagram showing an example of a URA (Uniform Rectangular Array) receiving antenna. By adopting a URA receiving antenna as shown in Fig. 23, it is possible to perform arrival direction estimation of two angles only by the URA receiving antenna without changing the directivity by a beamformer in the transmitting antenna array 24.

[0158] 2, the signal processing unit 10 has been described as including functional units such as the heart rate extraction unit 13 and the calculation unit 14. However, in one embodiment, the processing performed by the heart rate extraction unit 13 and / or the calculation unit 14 may be performed by an external computer or processor.

[0159] In addition, in one embodiment, the process in step S13 shown in FIG. 12 (SVD process) may be substituted by another subspace method.

[0160] In addition, in one embodiment, the process in step S13 shown in FIG. 12 (SVD process) may be omitted if the number of samples N of one chirp can be set to a large number, or if the inclusion of other noise can be eliminated by hardware techniques or the like.

[0161] In one embodiment, the process in step S24 shown in FIG. 13 may be omitted depending on the implementation situation.

[0162] In one embodiment, after pairing the first heart sound S1 and the second heart sound S2 in step S25 shown in FIG. 13, the RRI may be determined by taking the interval between the second heart sounds S2.

[0163] As described above, the electronic device 1 according to an embodiment detects weak vibrations such as heartbeats using, for example, a millimeter wave sensor having a plurality of transmitting antennas and a plurality of receiving antennas. When the electronic device 1 according to an embodiment does not detect a target, it detects the body movement of the target while changing the transmission phase of the antenna to perform the beamforming pattern of the transmitting antenna. On the other hand, when the electronic device 1 according to an embodiment detects the body movement of the target, it performs beamforming in the direction of the body movement and detects the heartbeat. In this way, the electronic device 1 according to an embodiment can improve signal quality by automatically detecting the direction of the human body. Therefore, the electronic device 1 according to an embodiment can improve the detection accuracy and / or detection range of the heartbeat. Therefore, the electronic device 1 according to an embodiment can detect the human heartbeat with high accuracy.

[0164] Although the present disclosure has been described based on the drawings and examples, it should be noted that a person skilled in the art can easily make various modifications or corrections based on the present disclosure. Therefore, it should be noted that these modifications or corrections are included in the scope of the present disclosure. For example, the functions included in each functional unit can be rearranged so as not to be logically inconsistent. Multiple functional units, etc. may be combined into one or divided. Each embodiment of the present disclosure described above is not limited to being implemented faithfully to each of the embodiments described, and may be implemented by combining each feature as appropriate or omitting a part. In other words, the contents of the present disclosure can be modified and corrected in various ways by a person skilled in the art based on the present disclosure. Therefore, these modifications and corrections are included in 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 be logically inconsistent, or replaced with each functional unit, each means, each step, etc. of other embodiments. In addition, in each embodiment, multiple functional units, each means, each step, etc. can be combined into one or divided. 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 may be implemented by combining each feature or omitting some features as appropriate.

[0165] The above-described embodiment is not limited to being implemented only 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, for example, the above-described embodiment may be implemented as a program executed by a device such as the electronic device 1.

[0166] Moreover, the electronic device 1 according to the above-mentioned 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 one embodiment may be implemented as, for example, a configuration such as a signal processing unit 10. In this case, the signal processing unit 10 may be implemented as having a function of processing signals handled by, for example, the transmitting antenna array 24 and the receiving antenna array 31. [Explanation of symbols]

[0167] 1 Electronic equipment 10 Signal Processing Section 11 Signal generation processing section 12 Receiving signal processing section 13 Heart Rate Extraction Unit 14 Calculation section 21 Transmit DAC 22 Transmitting circuit 23 Millimeter wave transmission circuit 24 Transmitting Antenna Array 31 Receiving Antenna Array 32 Mixer 33 Receiving circuit 34 Receive ADC 50 Communication Interface 60 External equipment

Claims

1. A transmitting antenna for transmitting a transmission wave; a receiving antenna for receiving a reflected wave of the transmission wave; a signal processing unit that detects vibrations caused by a heartbeat of an object reflecting the transmission wave based on a transmission signal transmitted as the transmission wave and a reception signal received as the reflected wave; Equipped with The signal processing unit includes: converting the signal based on the transmitted signal and the received signal into a first signal corresponding to a heart sound of the subject by using a first discrete wavelet transform technique; outputting a scalogram for the first signal by applying a continuous wavelet transform technique to the first signal; extracting a value at a frequency where the scalogram has a maximum value, converting the scalogram into a one-dimensional value, and outputting an envelope waveform of the phonocardiogram; The electronic device reconstructs the envelope waveform by applying a second discrete wavelet transform technique to the envelope waveform.

2. The electronic device according to claim 1 , wherein the signal processing unit uses a Haar wavelet as a wavelet basis for the second discrete wavelet transform.

3. the signal processing unit performs at least one of a first denoising process using an empirical Bayes method or a band limitation using a continuous wavelet, and a second denoising process using a frequency subtraction using a noise profile for artifact noise associated with nonlinear processing, on a signal based on the transmission signal and the reception signal before the process of converting the transmission signal into a first signal corresponding to the heart sound of the target; The electronic device according to claim 1 , further comprising: a maximal overlap multi-resolution analysis process for the denoised signal to improve a temporal resolution.

4. A step of converting a signal based on a transmission signal transmitted as a transmission wave and a reception signal received as a reflected wave of the transmission wave into a first signal corresponding to the heart sound of the target by applying a first discrete wavelet transform technique to the signal; outputting a scalogram for the first signal by applying a continuous wavelet transform technique to the first signal; a step of extracting a value at a frequency where the scalogram has a maximum value, converting the scalogram into a one-dimensional value, and outputting an envelope waveform of the heart sound waveform; reconstructing the envelope waveform by applying a second discrete wavelet transform to the envelope waveform; A method for controlling an electronic device, comprising:

5. For electronic devices, A step of converting a signal based on a transmission signal transmitted as a transmission wave and a reception signal received as a reflected wave of the transmission wave into a first signal corresponding to the heart sound of the target by applying a first discrete wavelet transform technique to the signal; outputting a scalogram for the first signal by applying a continuous wavelet transform technique to the first signal; a step of extracting a value at a frequency where the scalogram has a maximum value, converting the scalogram into a one-dimensional value, and outputting an envelope waveform of the heart sound waveform; reconstructing the envelope waveform by applying a second discrete wavelet transform to the envelope waveform; A program to execute.

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