Biosignal detection system

Abstract

To provide a technology for accurately detecting a biosignal of a person to be measured.SOLUTION: A biosignal detection system 100 includes: a sensor 64 acquiring a first vibration waveform including vibration BS corresponding to a biosignal of a person HM to be measured that is generated intermittently; a filter generation part 101 which generates a filter correcting frequency characteristic of the sensor or frequency characteristic of biological noise of the person to be measured by using a first vibration waveform during a first period when no biosignal is generated; and a correction part 102 correcting the first vibration waveform by using the filter.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to a biosignal detection system. [Background technology]

[0002] For example, Patent Document 1 discloses a vibration detection device including a correction filter that corrects the frequency and phase characteristics of a vibration signal obtained by a biological vibration detection unit with the inverse characteristics of the characteristics of the biological vibration detection unit. The filter coefficient of the correction filter is switched according to an input operation by a user or sensing by a sensor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-33943 A Summary of the Invention [Problem to be solved by the invention]

[0004] The filter generated in response to the input operation by the user or the sensing by a sensor other than the sensor that acquires the biosignal of the subject is not generated directly from the waveform acquired by the sensor that acquires the biosignal of the subject. Therefore, when the waveform including the vibration corresponding to the biosignal of the subject acquired by the sensor that acquires the biosignal of the subject is corrected using the above-mentioned filter, there is a problem that it is difficult to accurately detect the biosignal of the subject. [Means for solving the problem]

[0005] The present disclosure can be realized in the following forms.

[0006] According to one embodiment of the present disclosure, there is provided a biosignal detection system (100). The biosignal detection system includes a sensor (64) for acquiring a first vibration waveform including vibrations (BS) corresponding to an intermittently occurring biosignal of a subject (HM), a filter generating unit (101) for generating a filter for correcting a frequency characteristic of the sensor or a frequency characteristic of a bionoise of the subject using the first vibration waveform in a first period during which the biosignal is not generated, and a correction unit (102) for correcting the first vibration waveform using the filter.

[0007] According to the biosignal detection system of this embodiment, a filter for correcting the frequency characteristics of the sensor or the frequency characteristics of the bionoise of the subject is generated using the waveform of the first vibration waveform acquired by the sensor during a period in which the biosignal of the subject is not generated, and the first vibration waveform is corrected using the generated filter. Therefore, the biosignal of the subject can be detected with high accuracy. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is an explanatory diagram showing a schematic configuration of a biological signal detection system. [Diagram 2] FIG. 2 is an explanatory diagram showing a schematic configuration of a sensor. [Diagram 3] FIG. 1 is a block diagram showing the internal functional configuration of a biological signal detection system according to a first embodiment. [Figure 4] FIG. 2 is a diagram illustrating the frequency characteristics of heart sounds and biological noise. [Diagram 5] FIG. 4 is a process diagram of a biological signal acquisition process in the first embodiment. [Figure 6] FIG. 4 is a diagram illustrating a first vibration waveform. [Figure 7] FIG. 4 is a diagram showing a result of wavelet transform of a first vibration waveform. [Figure 8] FIG. 4 is a graph showing frequency characteristics in a first period. [Figure 9] FIG. 4 is a diagram showing the inverse characteristic of the frequency characteristic of a first vibration waveform in a first period. [Figure 10]FIG. 11 is a block diagram showing the internal functional configuration of a biological signal detection system according to a second embodiment. [Figure 11] FIG. 11 is a process diagram of a biological signal acquisition process according to a second embodiment. [Figure 12] FIG. 11 is a process diagram of a biological signal acquisition process according to the third embodiment. [Figure 13] 6 is a diagram showing frequency characteristics of a first vibration waveform after being corrected by a correction unit. FIG. [Figure 14] FIG. 13 is a diagram showing frequency characteristics in which the intensity of a narrow band frequency corresponding to the heart sound of a subject is increased. [Figure 15] FIG. 13 is a block diagram showing the internal functional configuration of a biological signal detection system according to a fourth embodiment. [Figure 16] FIG. 13 is a process diagram of a biological signal acquisition process according to the fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] A. First embodiment: As shown in FIG. 1, the biosignal detection system 100 in the first embodiment includes a biosignal acquisition module 60, an examination table 80, and a control device 90. The biosignal acquisition module 60 acquires biosignals of the subject HM that are generated intermittently. The biosignals are heart sounds of the heart HH of the subject HM that include mechanical or acoustic vibrations in the heart HH, or ballistocardial vibrations that are vibrations caused by the force of blood pumped by the heart HH. In this embodiment, the biosignal acquisition module 60 is disposed on the examination table 80, and acquires biosignals from the back HB of the subject HM lying on the examination table 80. The biosignal detection system 100 does not care whether the subject HM is wearing clothes or not when acquiring the biosignals.

[0010] Mechanical or acoustic vibrations in the heart HH are caused by the opening and closing of the valves of the heart HH, or the movement of blood flowing into or out of the heart HH. Heart sounds are sounds generated with the beating of the heart HH, and are elastic waves that propagate through a medium. Normally, heart sounds are periodic signals consisting of a first heart sound generated by the closure of the left and right atrioventricular valves at the beginning of ventricular systole, and a second heart sound generated by the closure of the aortic valve and pulmonary valve immediately after ventricular systole. Generally, the first heart sound is low-pitched and long, and the second heart sound is high-pitched and short. The period from the first heart sound to the second heart sound is the systole of the heart HH, and the period from the second heart sound to the first heart sound of the next cycle is the diastole of the heart HH.

[0011] The examination table 80 is an example of an article that comes into contact with the chest or back HB of the person to be measured HM. The "article that comes into contact with the chest or back of the person to be measured" includes various articles used when a person lies down, such as bedding, a bed, a futon, a sheet, a medical table, a hospital bed, a mat, a mattress, a floor, a sheet, a bed pad, a sofa bed, and various articles used when a person sits down, such as a chair, a chair, a sofa, and the like. The "article that comes into contact with the chest or back of the person to be measured" includes furniture, medical equipment, and the like, and any article that is used when a person lies down or sits down, regardless of its use. In addition, the "article that comes into contact with the chest or back of the person to be measured" is not limited to the whole of the article, but includes the case where it is a part of an article, such as the backrest of a chair, a part of the backrest, or a part of a mattress. The biosignal acquisition module 60 may be manufactured integrally with the examination table 80, or may be attached to a ready-made article by retrofitting it. In this disclosure, "retrofit" means not attached to or incorporated into the article at the time of manufacture or installation of the article, but attached or placed on the article independently of the manufacture or use of the article.

[0012] FIG. 2 shows an enlarged cross-sectional view of the range AR1 in FIG. 1. As shown in FIG. 2, the biosignal acquisition module 60 of this embodiment includes a sensor 64, a first medium 61, a second medium 62, and a container 66. The biosignal acquisition module 60 is embedded in a recess provided in the examination table 80 and fixed by friction with the material constituting the examination table 80. In FIG. 2, the heart HH and back HB of the subject HM, as well as the vibration BS emitted from the heart HH are shown in schematic form to facilitate understanding of the technology. The vibration BS is an example of a vibration corresponding to a biosignal. The biosignal acquisition module 60 does not have to be embedded in the examination table 80, and may be fixed to the surface of the examination table 80.

[0013] The sensor 64 acquires a first vibration waveform including a vibration BS corresponding to a biosignal of the subject HM. The sensor 64 is a microphone capable of detecting the vibration BS. From the viewpoint of accurately detecting the vibration BS corresponding to the biosignal, the sensor 64 is preferably highly sensitive enough to detect a minute signal such as a voltage in μV units. However, the sensor 64 is not limited to a microphone, and various sensors 64 capable of detecting the vibration BS, such as an accelerometer, a diaphragm, a piezoelectric element, etc., can be used.

[0014] The first medium 61 is a medium other than gas, such as a liquid, solid, or gel. The first medium 61 functions as a part of the propagation path of the vibration BS from the back HB to the sensor 64. In this embodiment, water is used for the first medium 61, and it is contained in the container 66 in a state where gas such as air has been substantially removed and in contact with the sensor 64. The first medium 61 is not limited to water, and may be a liquid such as antifreeze or oil, or a mixture of at least any of these in any combination.

[0015] The container 66 contains the first medium 61 and the sensor 64. The container 66 is formed of a synthetic resin such as an acrylic resin in a concave shape that defines an internal space for containing the first medium 61. The container 66 has an opening 66E for arranging the second medium 62. The opening 66E is disposed at a position close to the outside of the examination table 80 so as to be close to the person HM to be measured. The container 66 can be formed in any shape using various materials such as metal, resin, and ceramics. In the internal space of the container 66, the sensor 64 may be provided on the inner surface of the container 66 by, for example, pasting, provided that the sensor 64 is in contact with the first medium 61, or may be disposed in the center of the internal space by, for example, installing the sensor 64 on a protruding portion of a part of the inner wall of the container 66 that protrudes toward the center, or by hanging the sensor 64 from the inner wall of the container 66.

[0016] The second medium 62, together with the first medium 61, functions as a propagation path for the vibration BS from the back HB to the sensor 64. The second medium 62 is a medium other than gas, such as a liquid, solid, or gel. The second medium 62 is fixed to an opening 66E of the housing 66, and seals the sensor 64 and the first medium 61 in the internal space of the housing 66.

[0017] The second medium 62 has a second medium surface 62F and a second medium back surface 62B on the opposite side to the second medium surface 62F. The second medium 62 is fixed to the opening 66E with the second medium back surface 62B in contact with the first medium 61, and the gas between the first medium 61 and the second medium 62 is removed. That is, the first medium 61 and the second medium 62 are in contact with each other without any gas between them, and thus can be said to be in a state of contacting the sensor 64 as one medium. From the viewpoint of sealing the first medium 61 in the container 66, it is preferable that the second medium 62 is a solid. From the viewpoint of suppressing the attenuation of the vibration BS, the second medium 62 is formed using, for example, silicone rubber.

[0018] 3, the control device 90 is a computer including a CPU 91 as a central processing unit and a memory 92 such as a ROM or a RAM. The control device 90 includes a display unit 93 such as a display, and a communication unit 94 that acquires data from the sensor 64 by wired or wireless communication. The memory 92 stores a program for implementing the functions provided in this embodiment. The CPU 91 functions as a filter generating unit 101 and a correction unit 102 by expanding the program stored in the memory 92 on the RAM and executing it. Note that some or all of the functions of the filter generating unit 101 and the correction unit 102 may be implemented by hardware circuits.

[0019] The first vibration waveform acquired by the sensor 64 is input as an analog voltage signal to an AD converter (not shown) or the like, converted into a digital signal, and output to the control device 90 by wired communication or wireless communication. The wireless communication can be realized, for example, by a wireless connection through a wireless local network (LAN) conforming to the IEEE802.11 standard or wireless communication using Bluetooth (registered trademark).

[0020] The filter generating unit 101 generates a filter that corrects the frequency characteristics of the sensor 64 or the frequency characteristics of the biological noise of the subject HM, using the first vibration waveform in a first period excluding a second period in which a biological signal is generated in the first vibration waveform. Here, the second period is a period in which a biological signal is generated, and the first period is a period in which a biological signal is not generated. In other words, the first period is a period in which the first vibration waveform is acquired, excluding the second period. The biological noise means vibration generated from a living body, excluding heart sounds and ballistocardial trajectories, which are biological signals. The biological noise is, for example, breathing, pulse, organ movements, fetal movement, body movements (body movements), etc.

[0021] As shown in Fig. 4, the frequency peak of the heart sound exists in the range of 25 Hz to 50 Hz. Therefore, if the biological noise around 25 Hz or 50 Hz is amplified, the signal to noise ratio (SNR) of the heart sound deteriorates. The filter generating unit 101 generates a filter that attenuates the biological noise as shown in Fig. 4. Although not shown in Fig. 4, the frequency peak of the ballistocardiogram exists in the range of 10 Hz to 25 Hz.

[0022] The frequency characteristics of the sensor 64 change depending on the pressure applied to the sensor 64 or the constraint conditions of the sensor 64. The pressure applied to the sensor 64 depends on the weight, posture, etc. of the person HM to be measured. The constraint conditions of the sensor 64 include, for example, the method of installing the sensor 64 on the examination table 80 and the type of "item in contact with the chest or back of the person to be measured."

[0023] The correction unit 102 corrects the first vibration waveform using the filter generated by the filter generation unit 101.

[0024] The biosignal acquisition process shown in Fig. 5 is a process in which the biosignal detection system 100 acquires a biosignal of the subject HM. In the following, a case in which the biosignal detection system 100 acquires the heart sounds of the subject HM will be described as an example with reference to Fig. 5. First, in step S10, the sensor 64 acquires a first vibration waveform.

[0025] In step S20, the filter generating unit 101 performs a wavelet transform on the first vibration waveform. Fig. 6 shows the first vibration waveform obtained by extracting frequency components in a predetermined range through the wavelet transform. The predetermined range includes the heart sound frequencies of 25 Hz to 50 Hz. In Fig. 6, the first heart sound is indicated by an arrow as the "I sound" and the second heart sound is indicated by an arrow as the "II sound."

[0026] In step S30 of FIG. 5, the filter generating unit 101 divides each heartbeat using the first vibration waveform obtained by wavelet transform in step S20. Each heartbeat includes a first period in which neither the first nor the second heart sound occurs, and a second period in which the first and the second heart sounds occur. The filter generating unit 101 divides the period in which the first vibration waveform is acquired into a plurality of first and second periods. The filter generating unit 101 determines, as the first period, a predetermined period before the peak position corresponding to the first heart sound in the wavelet transformed first vibration waveform. For example, the filter generating unit 101 preferably determines, as the first period, a period from 0.35 seconds before the peak position corresponding to the first heart sound to 0.05 seconds before the peak position corresponding to the first heart sound.

[0027] In step S40, the filter generating unit 101 extracts the frequency characteristic of the first vibration waveform in one first period. When step S40 is executed for the first time, the one first period is the first period that occurs earliest among the first periods included in the first vibration waveform. When step S40 is executed repeatedly, the filter generating unit 101 extracts the frequency characteristic of the first vibration waveform in the first period immediately after the first period that was the target in the immediately preceding step S40. FIG. 7 shows the result of wavelet transform of the first vibration waveform for a period including one first period. The horizontal axis of FIG. 7 indicates time, the vertical axis indicates frequency, and the color shading indicates the intensity of each frequency at that time. In FIG. 7, the part surrounded by a rectangle corresponds to the first period. The filter generating unit 101 calculates the time average of the intensity of each frequency in the first period. FIG. 8 shows the calculation result of the time average of the intensity of each frequency in the first period. The horizontal axis of FIG. 8 indicates frequency, and the vertical axis indicates the time average of the intensity of each frequency. Extracting the frequency characteristic of the first vibration waveform in the first period means calculating the graph shown in FIG.

[0028] In step S50 of Fig. 5, the filter generating unit 101 generates a filter that corrects the frequency characteristics of the sensor 64 or the frequency characteristics of the biological noise of the subject HM, using the frequency characteristics of the first vibration waveform in the first period extracted in step S40. The filter generating unit 101 generates a filter having the inverse characteristics of the frequency characteristics of the first vibration waveform in the first period extracted in step S40, as shown in Fig. 9. Note that, when the first vibration waveform in the first period from which the frequency characteristics of the first vibration waveform are extracted in step S40 includes a waveform similar to a heart sound, the filter generating unit 101 does not generate the above-mentioned filter.

[0029] 5, the correction unit 102 corrects the first vibration waveform in a second period immediately following the first period in which the frequency characteristic of the first vibration waveform was extracted in step S40, using the filter generated in step S50. For example, when the first vibration waveform in the second period is corrected using the filter shown in FIG 9, the frequency components of the first vibration waveform around 15 Hz are attenuated most significantly.

[0030] In step S70, the CPU 91 of the control device 90 determines whether the first vibration waveforms of all the second periods have been corrected by the correction unit 102. If there is a second period in which the first vibration waveform has not been corrected, the CPU 91 returns the process to step S40. The process is returned to step S40, and step S50 is repeatedly executed, so that the filter generation unit 101 generates a filter for each first period separated by the biosignal. Furthermore, by repeatedly executing step S60, the correction unit 102 corrects the first vibration waveform of each second period using the filter generated in the first period immediately before it. If the first vibration waveforms of all the second periods have been corrected, the CPU 91 ends the biosignal acquisition process. As described above, the biosignal acquisition process is executed.

[0031] According to the biosignal detection system 100 in the first embodiment described above, the filter generating unit 101 generates a filter for correcting the frequency characteristic of the sensor 64 or the frequency characteristic of the bionoise of the subject HM by using the first vibration waveform in the first period, which is a period during which the biosignal of the subject HM is not generated, among the first vibration waveforms acquired by the sensor 64, and the correction unit 102 corrects the first vibration waveform by using the filter generated by the filter generating unit 101. Here, the filter generating unit 101 generates a filter having an inverse characteristic of the frequency characteristic of the first vibration waveform in the first period. The filter generated by the filter generating unit 101 is generated directly from the waveform acquired by the sensor 64, and therefore has information on the frequency characteristic of the sensor 64 or the frequency characteristic of the bionoise of the subject HM with high accuracy compared to a filter generated in response to an input operation by a user or sensing by a sensor other than the sensor 64 that acquires the biosignal of the subject HM. Therefore, the biological signals of the subject HM can be detected more accurately than when the first vibration waveform is corrected using a filter generated in response to a user input operation or sensing by a sensor other than sensor 64 that acquires the biological signals of the subject HM.

[0032] In this embodiment, the sensor 64 is provided on an article that comes into contact with the chest or back HB of the person being measured HM. Therefore, the biological signal of the person being measured HM can be detected without the person being measured HM having to hold the sensor 64.

[0033] In this embodiment, the filter generating unit 101 generates a filter for each first period separated by the biological signal, and the correcting unit 102 corrects the first vibration waveform of the second period using the filter generated in the first period immediately before it. Therefore, even if the frequency characteristics of the sensor 64 or the frequency characteristics of the biological noise of the subject HM change over time, the biological signal of the subject HM can be detected with high accuracy.

[0034] In the present embodiment, the filter generating unit 101 generates a filter by performing a wavelet transform on the first vibration waveform. Since the wavelet transform has higher time resolution and frequency resolution than the Fourier transform, the filter generating unit 101 can generate a filter with higher accuracy than when a filter is generated using the Fourier transform.

[0035] In addition, in this embodiment, when the first vibration waveform in a specific first period includes a waveform similar to a biological signal, the filter generating unit 101 does not generate a filter that corrects the frequency characteristics of the sensor 64 or the frequency characteristics of the biological noise of the subject HM in that first period. Therefore, a filter using the frequency characteristics of the first vibration waveform in the first period in which a biological signal may be generated due to arrhythmia or the like is not generated. Therefore, it is possible to suppress the generation of a filter that deteriorates the SNR of the subject HM.

[0036] B. Second embodiment: 10, a CPU 91b of a control device 90b in the second embodiment further includes a biological noise detection unit 103. The configurations of the components of the biological signal detection system 100 other than the biological noise detection unit 103 are the same as those in the first embodiment.

[0037] The biological noise detection unit 103 is realized by the CPU 91b expanding the program stored in the memory 92 into the RAM and executing it. The biological noise detection unit 103 may be realized by a circuit. The biological noise detection unit 103 detects a change in biological noise using the first vibration waveform. The biological noise changes, for example, when the body of the person HM moves or when the breathing state of the person HM changes from inhalation to exhalation. The biological noise detection unit 103 detects a change in biological noise by applying a band limit to the first vibration waveform acquired by the sensor 64. The biological noise detection unit 103 detects a change in the breathing state of the person HM using, for example, a signal with a period of 1 Hz or less included in the first vibration waveform.

[0038] Hereinafter, the biological signal acquisition process in the second embodiment will be described with reference to Fig. 11. Note that the same reference numerals are given to the parts in which the same processes as those in the biological signal acquisition process in the first embodiment shown in Fig. 5 are executed, and the description thereof will be omitted.

[0039] In step S61, the correction unit 102 corrects the first vibration waveform in all second periods included in the first vibration waveform acquired in step S10, using the filter generated in step S50.

[0040] In step S110, the sensor 64 acquires a first vibration waveform. The first vibration waveform acquired by the sensor 64 in step S110 is a first vibration waveform that immediately follows the first vibration waveform acquired in step S10.

[0041] In step S120, the CPU 91b of the control device 90b judges whether or not the biological noise detection unit 103 has detected a change in biological noise. If it is judged that a change in biological noise has been detected, the CPU 91b executes step S130. If it is judged that a change in biological noise has not been detected, the CPU 91b executes step S170.

[0042] In step S130, the filter generating unit 101 performs wavelet transform on the first vibration waveform acquired in step S110.

[0043] In step S140, similarly to step S30, the filter generating unit 101 divides each heartbeat using the first vibration waveform that has been wavelet transformed in step S130.

[0044] In step S150, the filter generating unit 101 extracts the frequency characteristic of the first vibration waveform in one first period, similarly to step S40. Here, the one first period is one first period after the biological noise changes, among the first periods included in the first vibration waveform acquired in step S110.

[0045] In step S160, the filter generation unit 101 generates a filter that corrects the frequency characteristics of the sensor 64 or the frequency characteristics of the biological noise of the subject HM, in the same manner as in step S50, using the frequency characteristics of the first vibration waveform in the first period extracted in step S150.

[0046] In step S170, the correction unit 102 corrects the first vibration waveform acquired in step S110. If it is determined that a change in the biological noise is detected in step S120, the correction unit 102 corrects the waveform of the first vibration waveform acquired in step S110 in a period before the biological noise changes, using the filter generated in step S50. In addition, the correction unit 102 corrects the waveform of the first vibration waveform acquired in step S110 in a period after the biological noise changes, using the filter generated in step S160. If it is determined that a change in the biological noise is not detected in step S120, the correction unit 102 corrects the first vibration waveform acquired in step S110, using the filter generated in step S50. As described above, the biological signal acquisition process in the second embodiment is executed.

[0047] According to the biological signal detection system 100 in the second embodiment described above, when the biological noise detection unit 103 detects a change in the biological noise, the filter generation unit 101 generates a filter that corrects the frequency characteristics of the sensor 64 or the frequency characteristics of the biological noise of the subject HM. In other words, when the biological noise does not change, the filter generation unit 101 does not generate a new filter. Therefore, the load of the calculation process for generating a filter can be reduced.

[0048] C. Third embodiment: The configuration of each part of the biological signal detection system 100 in the third embodiment is the same as that in the first embodiment. In the third embodiment, the correction unit 102 corrects the first vibration waveform using a filter that emphasizes the biological signal included in the first vibration waveform.

[0049] Hereinafter, the biological signal acquisition process in the third embodiment will be described with reference to Fig. 12. Note that the same reference numerals are given to the parts that execute the same processes as the biological signal acquisition process in the first embodiment shown in Fig. 5 and the biological signal acquisition process in the second embodiment shown in Fig. 11, and the description thereof will be omitted.

[0050] In step S210, the correction unit 102 corrects the first vibration waveform using a filter having the same frequency characteristics as the frequency characteristics of the first vibration waveform corrected in step S61. The correction unit 102 corrects the first vibration waveform using a filter having frequency characteristics as shown in FIG. 13, for example. Note that in step S210, the correction unit 102 may correct the first vibration waveform using a filter stored in advance in the memory 92. The correction unit 102 may correct the first vibration waveform using a filter that increases the intensity of a narrow band frequency corresponding to the heart sound of the subject HM, as shown in FIG. 14, for example. The narrow band frequency corresponding to the heart sound of the subject HM is, for example, 25 Hz to 40 Hz. The filters shown in FIG. 13 and FIG. 14 are examples of filters that emphasize a biological signal included in the first vibration waveform.

[0051] According to the biosignal detection system 100 in the third embodiment described above, the correction unit 102 corrects the first vibration waveform using the filter generated by the filter generation unit 101, and then corrects the first vibration waveform using a filter that emphasizes the biosignal included in the first vibration waveform. This makes it possible to further improve the SNR of the biosignal of the subject HM.

[0052] D. Fourth embodiment: 15, a CPU 91d of a control device 90d in the fourth embodiment further includes an interval calculation unit 104 and an estimation unit 105. The configurations of the components of the biological signal detection system 100 other than the interval calculation unit 104 and the estimation unit 105 are the same as those in the first embodiment.

[0053] The interval calculation unit 104 and the estimation unit 105 are realized by the CPU 91d expanding a program stored in the memory 92 into the RAM and executing it. Note that these may also be realized by circuits.

[0054] The interval calculation unit 104 calculates the interval of the biological signal by using the first vibration waveform corrected by the correction unit .

[0055] The estimation unit 105 estimates the physical or psychological state of the subject HM based on the interval of the biological signal calculated by the interval calculation unit 104. The physical or psychological state of the subject HM is, for example, stress, fatigue, drowsiness, wakefulness, autonomic nerve state, etc.

[0056] The biological signal acquisition process in the fourth embodiment will be described below with reference to Fig. 16. Note that the same reference numerals are given to the parts in which the same processes as those in the biological signal acquisition process in the first embodiment shown in Fig. 5 are executed, and the description thereof will be omitted.

[0057] In step S310, the interval calculation unit 104 calculates the interval between heart sounds from the first vibration waveform corrected in step S60. For example, the interval calculation unit 104 calculates the interval between first heart sounds from the first vibration waveform corrected in step S60.

[0058] In step S320, the estimation unit 105 estimates the physical or psychological state of the subject HM based on the heart sound interval calculated by the interval calculation unit 104. The estimation unit 105 estimates the stress of the subject HM, for example, by calculating LF / HF, which is an index of sympathetic nerve activity. Here, LF is the intensity of low-frequency components from 0.04 Hz to 0.15 Hz, and HF is the intensity of high-frequency components from 0.15 Hz to 0.4 Hz.

[0059] In step S330, the CPU 91d of the control device 90d causes the physical or psychological state of the subject HM estimated in step S320 to be displayed on the display unit 93. The display unit 93 may display, for example, a graph of the time change in LF / HF, or an estimated value of the stress of the subject HM.

[0060] According to the biosignal detection system 100 in the fourth embodiment described above, the interval calculation unit 104 calculates the interval of the biosignals using the first vibration waveform corrected by the correction unit 102, and the estimation unit 105 estimates the physical or psychological state of the subject HM based on the interval of the biosignals calculated by the interval calculation unit 104. Therefore, the estimation unit 105 can estimate the physical or psychological state of the subject HM more accurately than when the interval calculation unit 104 calculates the interval of the biosignals using the first vibration waveform not corrected by the correction unit 102. In addition, the estimation result of the physical or psychological state of the subject HM is displayed on the display unit 93, so that the subject HM can check his or her own physical or psychological state.

[0061] E. Other embodiments: (E-1) In the above embodiment, the biosignal is a heart sound or a ballistocardiogram. In contrast, the biosignal may be any vibration generated from a living body, such as respiration or pulse.

[0062] (E-2) In the above embodiment, the sensor 64 is provided on an article that comes into contact with the chest or back HB of the person being measured HM. In contrast, the sensor 64 does not have to be provided on an article that comes into contact with the chest or back HB of the person being measured HM.

[0063] (E-3) In the above embodiment, the biosignal acquisition module 60 has one sensor 64. However, the biosignal acquisition module 60 may have multiple sensors 64.

[0064] (E-4) In the above embodiment, the biological signal acquisition module 60 does not have to have at least one of the first medium 61, the second medium 62, and the container 66.

[0065] (E-5) The control device 90 and the methods described herein may be realized by a dedicated computer provided by configuring a processor and memory programmed to execute one or more functions embodied in a computer program. Alternatively, the control device 90 and the methods described herein may be realized by a dedicated computer provided by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control device 90 and the methods described herein may be realized by one or more dedicated computers configured by a combination of one or more hardware-programmed processors and memory and a processor configured with one or more hardware logic circuits. Also, the computer program may be stored in a computer-readable non-transitory tangible recording medium as instructions executed by a computer.

[0066] The present disclosure is not limited to the above-mentioned embodiment, and can be realized in various configurations without departing from the spirit of the present disclosure. For example, the technical features in the embodiments corresponding to the technical features in each aspect described in the Summary of the Invention column can be appropriately replaced or combined to solve some or all of the above-mentioned problems or to achieve some or all of the above-mentioned effects. Furthermore, if the technical feature is not described as essential in this specification, it can be appropriately deleted. [Explanation of symbols]

[0067] 60...biological signal acquisition module, 61...first medium, 62...second medium, 62B...back surface of second medium, 62F...surface of second medium, 64...sensor, 66...container, 66E...opening, 80...examination table, 90, 90b, 90d...control device, 91, 91b, 91d...CPU, 92...memory, 93...display unit, 94...communication unit, 100...biological signal detection system, 101...filter generation unit, 102...correction unit, 103...biological noise detection unit, 104...interval calculation unit, 105...estimation unit, BS...vibration, HB...back, HH...heart, HM...subject

Claims

1. A biosignal detection system (100), comprising: a sensor (64) for acquiring a first vibration waveform including a vibration (BS) corresponding to an intermittent biological signal of a subject (HM); a filter generating unit (101) that generates a filter that corrects the frequency characteristics of the sensor or the frequency characteristics of the biological noise of the subject, using the first vibration waveform in a first period that is a period during which the biological signal is not generated; A correction unit (102) that corrects the first vibration waveform using the filter. Biosignal detection system.

2. The biosignal detection system according to claim 1 , The sensor is provided on an article that comes into contact with the chest or back (HB) of the person being measured. Biosignal detection system.

3. The biosignal detection system according to claim 2, an interval calculation unit (104) that calculates an interval of the biological signal using the first vibration waveform corrected by the correction unit; and an estimation unit (105) that estimates a physical state or a psychological state of the subject based on the interval of the biological signal calculated by the interval calculation unit. Biosignal detection system.

4. The biosignal detection system according to claim 2, The frequency characteristic of the sensor varies depending on a pressure applied to the sensor or a constraint condition of the sensor. Biosignal detection system.

5. The biosignal detection system according to claim 4, The filter generating unit generates the filter for each of the first periods separated by the biological signal; The correction unit corrects the first vibration waveform in a second period during which the biological signal is generated, using the filter generated in the first period immediately before the second period. Biosignal detection system.

6. The biosignal detection system according to claim 4, The filter generation unit generates the filter by performing a wavelet transform on the first vibration waveform. Biosignal detection system.

7. The biosignal detection system according to claim 4, A biological noise detection unit (103) that detects a change in the biological noise using the first vibration waveform, The filter generating unit generates the filter when the biological noise detecting unit detects a change in the biological noise. Biosignal detection system.

8. The biosignal detection system according to claim 5 , When the first vibration waveform in the specific first period includes a waveform similar to the biological signal, the filter generating unit does not generate the filter in the specific first period. Biosignal detection system.

9. The biosignal detection system according to claim 4, The correction unit corrects the first vibration waveform using a filter that emphasizes the biological signal included in the first vibration waveform. Biosignal detection system.

10. A biosignal detection system according to any one of claims 3, 6, 7, 8 and 9, The biological signal is a heart sound or a ballistocardiogram. Biosignal detection system.

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