JP2000060846A - Biological sound detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a biological sound detector capable of obtaining biological sound signals not including environmental noise generated from something other than a subject. SOLUTION: While the environmental noise detected by two microphones 12 and 14 is almost the same size, since the sizes of heart sound detected by the two microphones 12 and 14 are different, in an environmental noise elimination means, the environmental noise is eliminated from first signals S1 outputted from a first microphone 12 based on second signals S2 outputted from a second microphone 14 and thus, a phonocardiogram not including the environmental noise generated from something other than the subject 16 is obtained. Since the heart sound is measured without considering the environmental noise, the heart sound in an exercise load is measured as well.

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the heart and respiration of a living body.
Body sounds generated in the body for diagnosing diseases such as organ systems
And outputs a body sound signal representing the body sound.
Body sound detection device
Of removing an environmental noise signal representing the generated environmental noise.
The present invention relates to a body sound detection device that can be used. [0002] 2. Description of the Related Art For example, diseases such as heart disease and respiratory system are considered.
A doctor's direct auscultation by auscultation to make a diagnosis
Has been done. However, with this auscultation diagnosis,
Heart sounds, breath sounds, pleural sounds,
The volume and tone of body sounds such as arterial sounds and bowel sounds are different.
Lacks objectivity and quantitativeness, and records body sounds
I can't keep it. [0003] Therefore, an alternative to auscultation, or auscultation
As a means of supplementing the law, a micro
Equipped with a microphone, and the
Detects body sounds and outputs body sound signals representing the body sounds
Diagnosis using a body sound detection device has been performed. Above raw
The body sound signal output from the body sound detection device is
Obtained as objective information without any individual differences
Can be left. For example, when worn on the chest skin
Detects heart sounds with a microphone
A diagnosis of a heart disease is made from the heart sound diagram. Heart disease for patients
If there is a patient, a heart sound chart obtained by measuring the patient
Is a heart caused by heart disease in addition to normal heart sounds
It can diagnose heart disease because of the noise
It is. [0004] However, the above-mentioned micro
The signals output from the microphone add to the body sounds required for diagnosis.
In addition, environmental noise generated by people other than the person being measured, such as people
Voices, footsteps, and door opening and closing sounds
In some cases, it is difficult to make an accurate diagnosis.
Was. In addition, part of the environmental noise is caused by the living tissue of the subject.
Because it propagates through the
Difficult to separate from sound and therefore accurate diagnosis
In order to do so, measurements must be taken in a quiet place,
It is extremely difficult to measure body sounds during dynamic loading.
Was. [0005] The present invention has been developed in view of the above circumstances.
The intended purpose is to be measured
Body sound signals that do not contain environmental noise
To provide a body sound detection device. [0006] In order to achieve the above object,
The gist of the present invention is the
Detects sound and outputs a body sound signal representing the body sound
A body sound detection device which is mounted on the skin of a living body and
At least two for detecting sound transmitted to the skin of a child
Microphone and at least two microphones
Is attached to the skin of the living body,
From the signal output from one of the microphones
Environmental noise based on the signal output from the other
Environmental noise removing means for removing the noise. [0007] In this way, at least two of the above
Environmental noise detected by the microphones
Whereas at least two microphones
Since the detected body sounds are different in magnitude, environmental noise
Output from one of the microphones in the removal means
Output from another one of the microphones based on the signal
The environmental noise is removed from the signal to be measured.
A body sound signal that does not contain external environmental noise can be obtained.
You. Therefore, body sounds can be reproduced without considering the environmental noise.
Since it can be measured, body sounds during exercise
It can also be measured. [0008] In another embodiment of the present invention, preferably, the body sound detection is performed.
The device has the same size for the at least two microphones.
Sound is detected from those microphones
Output the signal indicating the sound to the same signal strength
An amplifier for amplifying, wherein the environmental noise removing means is
Output from one of the microphones and amplified by the amplifier
Output from one of the microphones
The signal amplified by the amplifier is subtracted. This
In this case, the at least two microphones
Even if the sensitivities are different from each other,
The same size for the at least two microphones.
When sound is detected, it is amplified to the same signal strength and output.
Therefore, in the environmental noise removing means, the microphone
From the signal output from one of the microphones
By subtracting the signal output from the other
Thus, the environmental noise can be removed. [0009] Preferably, the body sound detecting device comprises:
The same loudness sound in the at least two microphones
If detected, output from those microphones
So that the signal strength of the signals indicating the beat sounds match each other.
The signals output from those microphones
Correction coefficient determining means for determining a correction coefficient to be
The correction coefficient determined by the number determination means
Correction means for correcting the signal output from the microphone
Wherein the environmental noise removing means is corrected by the correcting means.
Of the signal corrected by the correction means from one of the corrected signals
Subtract the other one. If you do this,
Note that the sensitivity of at least two microphones is different from each other
The same size by the correction coefficient determination means.
If a loud sound is detected,
Correction coefficients so that the signal strengths output from
Are determined and the microphones are
Is output from the correction coefficient determination means.
Since it is corrected by a positive coefficient, the environmental noise removing means
Is one of the signals corrected by the correction means,
By subtracting the other one of the corrected signals,
Environmental noise can be removed. Preferably, the body sound detecting device is
Signals output from the at least two microphones
The signal strength of the predetermined section is compared, and the signal strength of the predetermined section is compared.
The one with the lowest degree is inserted in the environmental noise elimination means.
The apparatus further includes an environmental noise determining unit that determines the signal to be subtracted.
Things. In this case, the environmental noise removing means
Microphone to detect the signal to be subtracted
Even if you do not set it, automatically by the environmental noise removal means
There is the advantage that the signal to be subtracted is determined. [0011] Preferably, said at least two mats are provided.
One of the microphones produces the body sound of the living body
Predetermined distance experimentally determined from the skin above the organ
Is mounted on the skin in the separation area separated by more than
At least two of the two microphones are
It is mounted on the skin above the organ that produces the body sound,
The environmental noise removing means is mounted on the skin in the separated area.
Based on the signal output from the microphone
The body mounted on the skin above the organs
Removing environmental noise from the signal output from the microphone
Things. This way, on the skin in the isolated area
Environmental noise and noise detected by the microphone
And the loudness of body sounds and the organs that generate the body sounds
Detected by a microphone mounted on the skin of the head
Comparing the loudness of environmental noise and body sound,
The loudness of body sounds is about the same as
The body mounted on the skin above the organs
Body sound detected by the microphone is sufficiently loud
Therefore, the environmental noise is removed by the environmental noise removing means.
Can get a strong enough signal if
Wear. [0012] Preferred embodiments of the present invention will be described below.
This will be described in detail with reference to the drawings. FIG. 1 shows the application of the present invention.
Of the heart sound detection device 10 for detecting a heart sound as a body sound.
It is a block diagram explaining a structure. In FIG. 1, the same as the heart sound detecting device 10
Provided with two microphones 12 and 14 having a configuration of
Have been. One of the two microphones (hereinafter
The first microphone 12) is a heart sound of the subject 16
Is detected on the epidermis in the center of the chest of the subject 16,
Apex, 4th intercostal sternum left edge, 2nd intercostal sternum left edge, 2nd intercostal
Located directly above the right border of the sternum, and the right border of the fourth intercostal sternum
Shown at a predetermined heart sound detection site (on the epidermis of the apex in FIG. 1)
Attached with non-adhesive tape, etc., to detect its heart sound
Sound transmitted to the skin at the site is detected. 1st micro
The sound detected by the microphone 12 is within the first microphone 12.
Signal at the piezoelectric element (not shown)
That is, the first signal S₁Is converted to The other of the two microphones (hereinafter referred to as the microphone)
The lower second microphone 14) is the heart of the subject 16
Predetermined experimentally determined distance from the skin above the gut
D (not shown)
It is pasted by a loop or the like.
Of the right abdomen, just a distance D away from the skin above
It is stuck on the skin. And the second microphone
Detects sound transmitted to the skin on which Lohon 14 is mounted
And a piezoelectric element (not shown) inside the second microphone 14
The electric signal, that is, the second signal S_TwoConvert to Up
The distance D is usually 5 to 20 cm, more preferably 10 to 20 cm.
It is within a range of 15 cm, and is detected by the second microphone 14.
The emitted heart sound is detected by the first microphone 12.
Environmental noise is almost equal to
Set to the value issued. Output from the first microphone 12
First signal S₁May have very low signal levels
Therefore, the signal is first amplified in the preamplifier 18. So
Then, the amplified first signal S₁Supplied to the filter 20
It is. The filter 20 includes four types of filters (not shown).
Equipped, the four types of filters are switched at any time,
The first signal S so as to be close to hearing between₁Bass component of
It is attenuated, and the treble component is emphasized. The main amplifier 22 is supplied from the filter 20.
The first signal S₁Is the amplified signal from the arithmetic and control unit 24.
SAM₁A / D converter 26 is a main amplifier.
22 supplied from the first signal S₁A / D conversion and operation
It is supplied to the control device 24. On the other hand, the output from the second microphone 14
Second signal S_TwoThe first signal S ₁As in
Amplified in the width unit 28 and is similar to the filter 20 described above.
Filtered by the filter 30 and supplied to the main amplifier 32
You. The main amplifier 32 outputs an amplified signal from the arithmetic and control unit 24.
SAM_TwoAccording to the second signal S_TwoAmplify and amplified
Second signal S_TwoIs an arithmetic control via the A / D converter 34
It is supplied to the device 24. A set of electrodes 36 represents the action potential of the myocardium.
Attached to a predetermined part of the living body to output the ECG signal SE
In the present embodiment,
In order to measure the electrocardiogram, the subject's 16 right and left feet
Each is attached. Heart output from electrode 36
The electric signal SE was amplified by the electrocardiographic signal amplifier 38.
Thereafter, the data is supplied to the arithmetic and control unit 24 via the A / D converter 40.
Be paid. Further, the sensitivity calibration button 42 is
No. SAM₁And SAM_TwoOf the sensitivity calibration operation
A signal for instructing a row is supplied to the arithmetic and control unit 24. Start-up
The stop 44 operates the start and stop of the heart sound detection device 10.
A signal for alternately instructing each time is supplied to the arithmetic and control unit 24,
The clock signal source 46 supplies the arithmetic and control unit 24 with a predetermined frequency.
A pulse signal SP is supplied. The arithmetic and control unit 24 includes a CPU 48, R
OM50, RAM52, and I / O port not shown
And a so-called microcomputer with
The CPU 48 executes a program stored in the ROM 50 in advance.
Signal processing while utilizing the storage function of the RAM 52 according to the RAM.
By performing the processing, the main amplifiers 22 and 32 are increased.
Width signal SAM₁And SAM_TwoSupply the amplified first
One signal S₁And the second signal S_TwoFrom the environmental noise
The obtained heart sound chart is obtained and displayed on the display screen of the display 54.
You. Further, the electrocardiographic lead waveform represented by the electrocardiographic signal SE, ie,
The electrocardiogram is displayed on the display screen of the display 54. FIG. 2 shows the performance of the heart sound detection device 10.
Function block describing the main control functions of the arithmetic and control unit 24.
FIG. In FIG. 2, the first signal storage means 60
Starts the heart sound detection device 10 by the start / stop button 44
When the first microphone 12 is activated,
First signal S amplified by amplifier 22₁Figure of RAM 52
A second signal storage means for storing in a first signal storage area not shown;
62 indicates that the heart sound detection device 10 is
When activated, it is detected by the second microphone 14.
The second signal S amplified by the main amplifier 32_TwoTo RAM 52
In a second signal storage area (not shown). The signal amplification factor determining means 64 includes a start / stop button.
When the heart sound detection device 10 is activated by the
And execution of the sensitivity calibration operation from the sensitivity calibration button 42.
No heart sounds when the command signal is supplied
The plurality of microphones provided in the heart sound detection device 10 in the section
Output from the horn and read into the arithmetic and control unit 24.
Signal strength, that is, the heart sound detection device
Environmental noise only to a plurality of microphones provided in the device 10
Is read into the arithmetic and control unit 24 when is detected.
Increase the amplification of those signals so that the signal strengths match.
decide. A method for determining a section where no heart sound is generated
For example, an electrocardiographic signal output from the electrode 36
A predetermined part (for example, R wave) of the electrocardiographic lead waveform represented by SE
As a reference, an experimental
The fixed section from the time when the predetermined time determined in
It is determined as a section where no heart sound is generated. Or before
Output from the microphone attached to the heart sound detection site
The waveform represented by the signal read by the arithmetic and control unit 24
A pre-stored standard heart sound waveform (eg, II sound represents
Waveform), the best match is obtained for the latter waveform.
As described above, the phases of the former waveforms are
The interval between heart sounds is defined as the section before and
Determines the later fixed section as a section where no heart sound is generated
I do. Then, a section where the heart sound is not generated
In the section determined as above, the plurality of microphones
From the controller and read by the arithmetic and control unit 24
Compare them so that their signal strengths match
Is determined. For example, set the initial value in advance
Is amplified at the amplification factor a determined by
The first signal S stored in the storage area and the second signal storage area
₁And the second signal S_TwoFrom the first signal S for a predetermined period₁
Average value of S_1AVAnd the second signal S_TwoAverage value of S _2AVIs calculated
And the signal amplification ratio between the main amplifier 22 and the main amplifier 32 is
S_2AV: S_1AVThe amplification factor is determined so that The environmental noise determining means 66 includes a plurality of micro-
Compare the signal strength of the signal output from the phone in a predetermined section
And the maximum signal strength output from those microphones
Or use the microphone with the smallest average signal strength
An environmental noise detection device mainly detecting the environmental noise.
Microphone, and the other microphones
Determined as a heart sound detection microphone that is detecting sound
You. That is, the signal stored in the first signal storage
First signal S₁And the second signal storage means 62
The remembered second signal S_Two, The maximum signal strength in a given section
Compare the average of degrees or signal strength. In this embodiment,
As shown in FIG. 1, the first microphone 12 is
Heart sound is detected loudly because it is worn on the upper skin
can do. Therefore, the first signal S₁And the second signal S
_TwoOf the maximum signal strength or the average value of the signal strength in a predetermined section of
By comparison, the second signal S_TwoIs smaller, so the second
Second signal S output from microphone 14_TwoWill be described later
Environment noise removing means 68 to determine the signal to be subtracted.
You. The environmental noise removing means 68 has a preset
For the predetermined section, the environmental noise determination means 66
Environmental noise detection microphone that detects environmental noise
Microphones other than the microphone determined in
From the signal output from the heart sound detection microphone,
Subtract the signal output from the ambient noise detection microphone
Good. That is, the first signal S₁From the second signal S_TwoDeducted
I will The first microphone 12 is provided inside the living body.
Evolving heart sounds (and heart murmurs if you have heart disease)
Mainly detected, but generated from other than subject 16
The environmental noise is also detected. On the other hand, the environmental noise
Is generated at a place relatively far from the subject 16,
The second microphone 14 is also detected with substantially the same strength.
Further, the two microphones 12 and 14 are used for the signal amplification.
When the same volume sound is detected by the rate determining means 64
Is calibrated to be amplified to the same signal strength
The first signal S₁Of the environmental noise component contained in
Magnitude and second signal S_TwoOf the environmental noise component contained in
The magnitude is almost the same. Therefore, the first signal S₁From the second letter
No. S_TwoIs subtracted, the first signal S₁From the environmental miscellaneous
The sound component is removed. On the other hand, the second microphone 14
Worn on the skin at a distance D from the skin above the heart
Heart sounds detected by the second microphone 14
(And heart murmur) are detected by the first microphone 12
Is weaker than the heart sounds (and heart murmurs)
Signal S₁From the second signal S_TwoEven if is subtracted,
And heart murmur) components are hardly removed. The heart sound waveform display means 70 is a means for removing environmental noise.
Displaying the signal from which the environmental noise has been removed in step 68
54. FIG. 3 and FIG.
It is a flowchart for explaining the main part of the control function,
FIG. 3 shows that the start and stop button 44 activates the heart sound detection device 10.
Is activated, and the sensitivity calibration button 42 is pressed.
FIG. 4 is a sensitivity calibration routine executed when
Heart sound measurement routine executed after completion of sensitivity calibration routine
It is. The sensitivity calibration routine shown in FIG.
In step SA1 (hereinafter, steps are omitted),
Timers and registers not shown are initialized, and the next SA2
Is based on the electrocardiographic signal SE output from the electrode 36,
It is determined whether the R wave of the electrocardiographic lead waveform has been detected.
While the judgment of SA2 is denied, SA2 is repeated.
If the answer is affirmative, the next SA3
The first elapsed time set after the detection of the R wave
T₁Is determined. This first elapsed time
T₁Is a time of about 0.5 to 0.6 seconds, and an R wave is detected.
From the time when the heart sound I sound is generated,
Experiment beforehand as the time until the end of II or III sound
It is a value that has been determined. While the judgment at SA3 is denied, S
A3 is repeatedly executed.
This is the section where no error occurs, so the first signal storage
At SA4 corresponding to step 60, the first microphone 1
2 and a preset amplification factor a in the main amplifier 22
The first signal S amplified by₁Is the RAM 52 (not shown)
Second signal storage means sequentially stored in one signal storage area and subsequent
In SA5 corresponding to 62, the second microphone 14
And amplified by the main amplifier 32 at the amplification factor a.
Signal S_TwoIs stored in a second signal storage area (not shown) of the RAM 52.
It is stored sequentially. At SA6, the first progress is made at SA3.
Time T₁Has passed for the second time since it was determined that
Time T_TwoIs determined. This second passage
Time T_TwoIs IV after the completion of heart sound II or III
Preset as a time shorter than the time until the sound is generated
For example, about 0.2 to 0.3 seconds.
It is. While the determination in SA6 is denied, the above SA
4 is repeatedly executed, the first signal S₁
And the second signal S_TwoIs continued. However, if the determination in SA6 is affirmed,
In the subsequent SA7, the content of the timer t is
After clearing, for example, it is set to about 10 seconds in advance.
Third elapsed time T_ThreeIs determined. This
If the determination of SA7 is denied,
It is executed repeatedly. That is, a heart sound is generated every beat
The first signal S in a preset section where the₁You
And the second signal S_TwoIs stored. If the determination at SA7 is affirmative, S
A8 and subsequent steps are executed. First, in SA8, it smells SA4
Stored in a first signal storage area (not shown) of the RAM 52.
First signal S₁Average value of S_1AVIs calculated, and the following SA9
Then, in SA5, the second signal (not shown) of the RAM 52
Second signal S stored in storage area_TwoAverage value of S_2AVIs calculated
Will be issued. The following S corresponding to the signal amplification factor determining means 64
In A10, the average value S of the first signal calculated in SA8 is calculated.
_1AVAnd the average value S of the second signal calculated in SA9_2AVAnd
Signal amplification of the main amplifier 22 on the first microphone 12 side.
And the signal amplification rate of the main amplifier 32 on the second microphone side
And the ratio is S_2AV: S_1AVSo that
The signal amplification factor of the band switches 22 and 32 is determined. Sand
The amplified signal SA supplied to the main amplifiers 22 and 32
M₁And SAM_TwoIs determined. Suppose_1AV> S_2AV
Is detected, the two microphones 12 and 14 are detected.
Since the environmental noise emitted is of the same magnitude, the first noise
The sensitivity of the microphone 12 is better. That
For example, for example, the main amplifier 22 on the first microphone 12 side
Of the second microphone 14 side.
The amplification factor of the amplifier 32 is equal to the initial value a. _1AV/ S_2AVDouble
So that the amplified signal SAM_TwoTo determine. Next, the heart sound measurement routine of FIG. 4 will be described.
I do. First, at SB1, a timer and a register (not shown) are again
The contents of the data are initialized and stored in the subsequent first signal storage means 60.
In the corresponding SB2, the output from the first microphone 12
First signal S amplified by main amplifier 22₁Of RAM 52
It is sequentially stored in a first signal storage area (not shown),
In SB3 corresponding to the signal storage means 62, the second micro
The second signal output from the telephone 14 and amplified by the main amplifier 32
No. S_TwoAre sequentially stored in a second signal storage area (not shown) of the RAM 52.
It is stored next. Further, in the following SB4, from the electrode 36
The ECG signal S output and amplified by the ECG signal amplifier 38
E is stored in the RAM 52. At the subsequent SB5, the timer t is set at SB1.
After the contents are initialized, the preset heart sound diagram measurement
Time T_hIs determined. This heart sound chart
Fixed time T_hIs set, for example, to several seconds to several tens of seconds.
As long as the determination at SB5 is denied, after SB2
Are repeatedly executed, the first signal S₁, Second
Signal S_TwoAnd the storage of the electrocardiographic signal SE is continued. FIG.
Is the number stored by repeating the above SB2 to SB5
One signal S₁And the second signal S_TwoShows an example of the waveform represented by
FIG. 5A shows the first signal S.₁Shows the waveform represented by
FIG. 5B shows the second signal S_TwoShows the waveform represented by
You. However, if the determination at SB5 is affirmative,
In this case, SB6 to SB6 corresponding to the following environmental noise determination means 66
SB8 is executed. First, at SB6, at SB2
The stored first signal S₁Average value of S_1AVIs calculated and continued
At SB7, the second signal S stored at SB3 is_TwoThe average of
Value S_2AVIs calculated. Then, in the following SB8,
Average value S of first signal calculated in SB6_1AVAnd at SB7
Average value S of calculated second signal_2AVIs compared to
A second microphone that outputs a second signal with a small average value
Environmental noise detection in which the lophone 14 mainly detects environmental noise.
Output microphone and output first signal with large average value
The first microphone 12 mainly detects heart sounds.
Heart sound detection microphone. SB corresponding to the following environmental noise removing means 68
In step 9, the first microphone used as the heart sound detection microphone in SB8
From the signal output by the microphone 12, the environmental noise detection
The second microphone 14 determined by the microphone outputs
The signal is subtracted. That is, as shown in FIG.
First signal S₁From the waveform represented by, the fourth waveform shown in FIG.
2 signal S_TwoIs subtracted from the waveform represented by
The shape is extracted. In the subsequent SB10, the extraction in SB9 is performed.
The outputted heart sound waveform is the heart stored in SB4.
Along with the ECG lead waveform (electrocardiogram)
It is displayed on one time axis. FIG. 6 is displayed in SB10.
3 shows an electrocardiographic waveform and a heart sound waveform. As described above, according to the present embodiment, two
The environmental noise detected by the microphones 12 and 14 is substantially
These two microphones are the same size
Is the volume of heart sounds detected on 12 and 14 different?
In the environmental noise removing means 68 (SB9),
Second signal S output from microphone 14_TwoBased on
And the first signal S output from the first microphone 12₁
From the subject 16
A heart sound chart that does not include the environmental noise generated from the above is obtained. Subordinate
Measure heart sounds without regard to the environmental noise
Measurement of heart sounds during exercise.
Can also be. According to the present embodiment, two micro
Even if the sensitivities of the phones 12 and 14 are different from each other,
By means of the main amplifiers 22, 32, these two microphones
When the same loudness is detected in 12 and 14, the same signal
Signal is amplified to signal strength and output.
In the removing means 68 (SB9), the first microphone 12
Output first signal S₁From the second microphone 14
Signal S output from_TwoBy subtracting
The environmental noise can be removed. According to the present embodiment, the heart sound detecting device 1
0 is the signal output from the two microphones 12 and 14.
No. S₁, S_TwoOf the signal intensity in a predetermined section of_1AV, S
_2AVAre compared, and the average value of the signal strength in the predetermined section is
S_1AV, S_2AVSignal S is low_TwoThe environmental noise removal means
Ring to be determined as a signal to be subtracted in 68 (SB9)
It further includes boundary noise determining means 66 (SB8).
Therefore, the signal to be subtracted by the environmental noise removing means 68 (SB9)
Without having to decide in advance the microphone to detect
However, it is automatically inserted by the environmental noise elimination means 68 (SB9).
There is the advantage that the signal to be drawn is determined. Further, according to the present embodiment, the subject 16
Attached on the skin at a distance D from the skin above the heart
Noise detected by the detected second microphone 14
And the loudness of the heart sound and the skin above the apex of the subject 16
Detected by the first microphone 12 worn on the skin
Comparing the loudness of environmental noise and heart sound,
The loudness of heart sounds is the
The heart sound detected by the microphone 12 is sufficiently large
Therefore, in the environmental noise removing means 68 (SB9)
A signal that is strong enough when environmental noise is removed
Obtainable. Next, another embodiment of the present invention will be described with reference to the drawings.
This will be described in detail. In the following examples,
Portions common to the above-described embodiments are denoted by the same reference numerals, and description thereof is omitted.
Omitted. FIG. 7 shows another embodiment of the present invention.
Heart sounds that detect heart sounds as body sounds as in the previous embodiment
As for the detecting device, the arithmetic and control unit 2 of the heart sound detecting device
FIG. 4 is a functional block diagram illustrating a main part of the control operation of FIG.
You. In the heart sound detection device of the present embodiment, the mechanism of the device and
The circuit configuration is the same as that of the embodiment of FIG.
The control operation by the device 24 is different. That is, this implementation
In the example heart sound detecting device, the main amplifiers 22 and 32 have predetermined values.
Amplified signal SAM₀Are output respectively.
In the main amplifiers 22 and 32, the
Signals from the input and output terminals 12 and 14 are amplified,
Calculation processing in the two microphones 12 and 14
If the same loudness is detected, those two
The signals output from the crophones 12 and 14 have the same signal strength.
The correction coefficient to be corrected for the
Signals output from the terminals 12 and 14 are corrected by the correction coefficient.
It is supposed to be. In the functional block diagram shown in FIG.
The correction coefficient determining means 72 includes two microphones 1
If the same sound is detected in 2 and 14, those 2
The arithmetic and control unit 2 which is output from the microphones 12 and 14
4, the signal intensities are compared with each other.
Correct so that they match. That is, the start / stop button
When the heart sound detection device is activated by the
And execution of the sensitivity calibration operation from the sensitivity calibration button 42.
Section where no heart sound is generated when a signal is supplied
Output from the two microphones 12 and 14
The strength of the signal read into the arithmetic and control unit 24 is
Correction factor for correcting the signal strength of
To determine. The section where no heart sound is generated is determined
This is performed in the same manner as in the above embodiment. For example, a section where the heart sound is not generated
In the section determined as, two microphones 1
2 and 14, the first signal storage area and the
First signal S stored in two-signal storage area₁And second letter
No. S_TwoBased on the first signal S₁Average value of S_1AVand
Second signal S_TwoAverage value of S_2AVAnd the first signal S₁To
Correction coefficient r to correct₁And the second signal S_TwoCorrector who corrects
Number r_Two(= R₁: R_Two) Is S_2AV: S_1AVbecome
The correction coefficient is determined as follows. The correcting means 74 is provided by a plurality of microphones.
The output signal is added to the correction coefficient determined by the correction coefficient determination means 72.
Correct with a positive coefficient. That is, the first microphone 12 and
And the second microphone 14 are attached to the skin of the subject 16
In this state, the signal is stored in the first signal storage unit 60.
First signal S₁And the second signal storage means 62
The remembered second signal S_TwoTo the correction coefficient determining means 7
Correction coefficient r determined in 2₁, R_TwoCorrect with. FIGS. 8 and 9 show an arithmetic and control unit according to this embodiment.
4 is a flowchart for explaining a main part of a control operation of the device 24.
FIG. 8 shows a sensitivity calibration routine, and FIG. 9 shows a heart sound measurement.
It is a routine. In FIG. 8, SC1 to SC9 are the same as those described above.
3 is the same as SA1 to SA9 of the sensitivity calibration routine of FIG.
As a result of the processing, a heart sound is generated every beat
No, that is, in a predetermined section where only environmental noise is detected
First signal S₁And the second signal S_TwoIs memorized.
These first signals S₁Average value of S_1AVAnd the second signal S_Twoof
Average value S_2AVIs calculated. The SC corresponding to the subsequent correction coefficient determining means 72
In 10, the average value S of the first signal calculated in SC8_1AV
And the average value S of the second signal calculated in SC9_2AVFrom the
One signal S₁Correction coefficient r for correcting₁And the second signal S_TwoComplement
Correction coefficient r_TwoAnd the ratio is S_2AV: S_1AVSo that
Next, the correction coefficient is determined. Suppose_1AV> S_2AVIn
Are detected by the two microphones 12 and 14.
The environmental noise is the same
One signal S₁Is larger, so for example,
Correction coefficient r₁Is 1 and the correction coefficient r_TwoS_1AV/ S_2AV
To decide. Next, the heart sound measurement routine of FIG. 9 will be described.
I do. In FIG. 9, first, not shown again in SD1.
The contents of the timer and the register are cleared, and the following correction means 7
In SD2 corresponding to No. 4, the signal is output from the first microphone 12.
And amplified by the main amplifier 22 at the amplification factor a.
One signal S₁Is the correction coefficient r determined in SC10 of FIG. ₁
Are sequentially corrected. In SC10, r₁Is determined to be 1
The first signal S₁Is the resulting value
It is said. And corresponds to the subsequent first signal storage means 60
In SD3, the first signal S successively corrected in SD2₁Is R
It is sequentially stored in a first signal storage area (not shown) of the AM 52.
You. In SD4 corresponding to the following correction means 74,
The output from the second microphone 14 and the main amplifier 32
And the second signal S amplified by the amplification factor a_TwoIs SC1 in FIG.
Correction coefficient r determined at 0_TwoAre sequentially corrected. Said S
In C10, the correction coefficient r_TwoIs S _1AV/ S_2AVDecided to
In SD4, the second signal S_TwoAnd the correction coefficient r_TwoWith
The product is calculated. Then, the subsequent second signal storage means 62
In the corresponding SD5, the second signal S sequentially corrected in SD4
_TwoAre sequentially stored in a second signal storage area (not shown) of the RAM 52.
Remembered. In subsequent SD6 and subsequent steps, SB4 in FIG.
The same processing is performed thereafter. That is, in SD6
The electrocardiographic signal SE is sequentially stored in the RAM 54.
Preset heart sound measurement time T_hUntil S elapses
The first signal S is obtained by repeatedly executing D2 and subsequent steps.
₁And the second signal S_TwoIs corrected and stored. When the determination in SD7 is affirmative,
In SD8 to SD10, the corrected first signal S₁
Of the predetermined section of_1AVAnd the corrected second signal S
_TwoOf the predetermined section of_2AVIs calculated and the two are compared.
By doing so, the second signal that outputs a second signal with a small average value
Ring in which the two microphones 14 mainly detect environmental noise
Environment noise detection microphone, the first signal with a large average value
The first microphone 12 that outputs the signal mainly detects heart sounds.
It is assumed to be the outgoing heart sound detection microphone. And continued
In SD11 corresponding to the environmental noise removing means 68,
First signal S stored in SD3₁From SD5
The second signal S_TwoIs subtracted, the first signal S
₁From which the environmental noise is removed, and a heart sound waveform representing a heart sound is obtained.
Is extracted. In the following SD12, the values calculated in SD11 are calculated.
The heart sound waveform is the electrocardiogram signal S stored in SD6.
At the same time as the ECG waveform (electrocardiogram) represented by E
Displayed on the axis. As described above, according to the present embodiment, two
If the sensitivities of the microphones 12 and 14 are different from each other,
Even in this case, the correction coefficient determination means 72 (SC10)
If one sound is detected, those microphones 1
So that the signal intensities output from 2, 14 match each other.
Correction coefficient r₁, R_TwoAre determined and those microphones are
The signals output from the components 12 and 14 are output to the correction means 74 (S
D2, SD4), the correction coefficient determining means 72 (SC1
Correction coefficient r determined in 0)₁, R_TwoBe corrected by
Therefore, the environmental noise removing means 68 (SD11)
First signal S corrected in stage 74 (SD2)₁From the correction
Second signal S corrected by means 74 (SD4)_TwoDeduct
By doing so, the environmental noise can be removed. An embodiment of the present invention will now be described with reference to the drawings.
Although described, the present invention is applicable in other aspects.
You. For example, in the above-described embodiment, when the heart sound is measured
Interval T_hWas preset to several seconds to several tens of seconds,
A predetermined portion of the electrocardiographic lead waveform represented by the signal SE that repeats periodically
Position, for example, an R-wave, and
Calculate the number of beats and read the signals for the specified number of beats.
It may be. In the above-described embodiment, the environmental noise
In step 66 (SB8, SD10), the environmental noise detection
Although the crophone has been determined, the environmental noise determination means 66
(SB8, SD10) are not provided and heart sounds are detected in advance.
Heart sound detection microphone and environment for detecting environmental noise
A noise detection microphone has been determined and its heart sound detection
Microphone at a predetermined heart sound detection site of the subject 16
Wear the environmental noise detection microphone on top of the heart
On the skin in the separation area that is more than a predetermined distance D from the skin
It may be worn. In the above-described embodiment, the heart sound is used as the body sound.
Sound was detected, but breathing, pleural, arterial, and bowel sounds
And other heart sounds may be detected. In the above embodiment, the subject 16
Two microphones were attached to the skin, but three
It may be the above. In addition, the present invention does not depart from its gist.
Various changes can be made in the boxes.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a configuration of a heart sound detection device according to one embodiment of the present invention. FIG. 2 is a functional block diagram illustrating a main part of a control function of the electronic control device of the embodiment of FIG. 1; FIG. 3 is a flowchart illustrating a main part of a control operation of the electronic control device according to the embodiment of FIG. 1, and is a diagram illustrating a sensitivity calibration routine. FIG. 4 is a flowchart illustrating a main part of a control operation of the electronic control device according to the embodiment of FIG. 1, and is a diagram illustrating a heart sound measurement routine. FIG. 5 is a diagram showing an example of a waveform represented by a first signal and a second signal, wherein (a) shows a waveform represented by the first signal;
(B) shows the waveform represented by the second signal. FIG. 6 is a diagram showing an example of an electrocardiographic waveform and a heart sound waveform displayed on a display. FIG. 7 is a functional block diagram illustrating a main part of a control function of an arithmetic and control unit according to another embodiment of the present invention. 8 is a flowchart illustrating a main part of a control operation of the electronic control device according to the embodiment of FIG. 7, and is a diagram illustrating a sensitivity calibration routine. 9 is a flowchart illustrating a main part of a control operation of the electronic control device of the embodiment in FIG. 7, and is a diagram illustrating a heart sound measurement routine. [Description of Symbols] 10: heart sound detecting devices 12, 14: microphones (heart sound sensors) 22, 32: main amplifier 66: environmental noise determining means 68: environmental noise removing means 72: correction coefficient determining means 74: correcting means

Claims (1)

Claims 1. A body sound detection device for detecting a body sound generated in a living body and outputting a body sound signal representing the body sound, wherein the body sound detection device is mounted on a skin of a living body. At least two microphones for detecting sound transmitted to the skin; and a signal output from one of the microphones when the at least two microphones are mounted on the skin of the living body. A body noise detecting device, comprising: an environmental noise removing unit configured to remove environmental noise based on a signal output from the other one.