A single-sensor-based multi-frequency band mechanical wave detection device for heart and lung

Abstract

The present application relates to a kind of single sensor-based heart-lung multi-band mechanical wave detection device, belong to medical instrument technical field, it is related to heart-lung signal detection technology.By using the first transmission component, piezoelectric film, second transmission component and absolute pressure sensor fixed layer stack composition single mechanical wave sensor, synchronous stable collection is caused by chest wall vibration piezoelectric film and absolute pressure sensor electric signal, by signal amplification circuit processing, transmission to multi-band signal extraction module, digital piezoelectric signal is decomposed to obtain respiratory wave, ultra-low frequency heart wave, heart shock signal and heart-lung sound signal, digital absolute pressure signal is filtered to obtain static pressure value, the degree of chest wall adhesion is embodied, it is realized that single sensor on synchronous extraction heart-lung multi-band mechanical vibration information, to understand heart-lung activity and state provides a kind of efficient, portable mode.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of medical devices, and relates to heart-lung signal detection technology, in particular to a heart-lung multi-frequency band mechanical wave detection device based on a single sensor. BACKGROUND

[0002] The movement of the heart and the lungs is inseparable. Heart-lung diseases are one of the important factors threatening people's life and health worldwide, and the trend of youth is increasingly prominent. Daily monitoring of the heart and lungs and early warning of diseases are a key task in medicine, which puts new requirements on sensors for detecting the heart and lungs. Traditional sensing technologies include single detection of heart-lung mechanical information such as heart sound, lung sound auscultation, respiratory wave (chest wall expansion and contraction caused by respiration), heart shock signal (SCG, local chest wall vibration caused by heartbeat), etc. Heart-lung movement is a composite movement containing mechanical waves of different frequencies. However, the above single sensing technology can only reflect a certain frequency band of heart-lung movement. To fully reflect the mechanical wave movement of the heart and lungs, the signals of the above multiple sensors need to be collected. At the same time, the different degrees of adhesion of the sensor and the human chest wall will affect the effect of the collected mechanical wave, change the shape and quality of the signal waveform, and the current heart-lung vibration monitoring technology does not fuse the static pressure to reflect the adhesion of the sensor and the human chest wall. To fully reflect the mechanical activity information of the heart and lungs through the vibration waveform, the static pressure needs to be extracted.

[0003] In the implementation process of the sensor, the wideband characteristics of the piezoelectric film show the potential to detect low-frequency to high-frequency mechanical vibrations simultaneously. This makes it possible to obtain the above multi-frequency band heart-lung vibration signals on a single sensor. The present application proposes a single sensor heart-lung multi-frequency band mechanical wave detection device based on a piezoelectric film, which can simultaneously extract respiratory waves, ultra-low frequency heart beat signals, heart shock signals and heart-lung sound signals. To reflect the adhesion of the sensor and the human body, an absolute pressure sensor is used to collect the static pressure between the sensor and the human body as a quantitative adhesion. The present application provides an efficient and portable way to fully understand the heart-lung mechanical vibration information and reflect the heart-lung activity and state, and can be further applied to wearable and portable devices for heart-lung, providing the possibility for early detection and timely treatment of heart-lung abnormalities, and helping to avoid the increase of medical costs and the waste of medical resources. SUMMARY

[0004] To solve the above problems, the present application provides a heart-lung multi-frequency band mechanical wave detection device based on a single sensor, which synchronously collects piezoelectric signals and absolute pressure signals at the heart-lung chest position, and further extracts the piezoelectric signals into respiratory waves, ultra-low frequency heart beat signals, heart shock signals and heart-lung sound signals, and multi-frequency band reflects the mechanical vibration information of the heart and lungs.

[0005] In one aspect, the embodiment of the present application provides a single-sensor-based heart-lung multi-band mechanical wave detection device, comprising a single mechanical wave sensing module, a signal receiving circuit and a multi-band signal extraction module, wherein,

[0006] The single mechanical wave sensing module is used for synchronously collecting piezoelectric signals and absolute pressure signals at a heart-lung thoracic cavity position, and comprises a first transmission component, a piezoelectric film, a second transmission component and an absolute pressure sensor which are sequentially stacked.

[0007] The signal receiving circuit is used for amplifying and analog-digital converting the piezoelectric signals and the absolute pressure signals collected by the single mechanical wave sensing module to obtain digital piezoelectric signals and digital absolute pressure signals.

[0008] The multi-band signal extraction module comprises a signal decomposition module and a signal filtering module, wherein the signal decomposition module is used for decomposing the digital piezoelectric signals to obtain respiratory waves, ultra-low frequency heart beat signals, heart shock signals and heart-lung sound signals, and the signal filtering module is used for filtering the digital absolute pressure value signals to obtain static pressure values.

[0009] Based on the further improvement of the above method, the first transmission component is used for transmitting vibration waves of a human thoracic cavity to the piezoelectric film.

[0010] The piezoelectric film is used for detecting analog piezoelectric signals caused by the pressure transmitted by the first transmission component.

[0011] The second transmission component is used for fixing the piezoelectric film and the absolute pressure sensor as intermediate parts and transmitting the pressure to the absolute pressure sensor.

[0012] The absolute pressure sensor is used for detecting analog absolute pressure signals caused by the pressure.

[0013] Based on the further improvement of the above method, the first transmission component specifically comprises:

[0014] A soft insulating material suitable for contacting a human body and having good mechanical wave conduction ability is adopted.

[0015] A regular shape with parallel upper and lower surfaces is adopted, wherein the upper surface contacts the human body and the lower surface contacts the piezoelectric film.

[0016] The lower surface has the same shape as the piezoelectric film and a cross-sectional area slightly smaller than that of the piezoelectric film.

[0017] Based on the further improvement of the above method, the lower surface of the first transmission component is aligned with the piezoelectric film in a center-to-center manner and is fixed by edge bonding.

[0018] Based on the further improvement of the above method, the second transmission component specifically comprises:

[0019] The second transmission component is made of a hard insulating material with good mechanical wave conduction ability;

[0020] The regular shape has parallel upper and lower surfaces, the upper surface is in contact with the piezoelectric film, and the lower surface is in contact with the absolute pressure sensor;

[0021] The upper surface has the same shape as the piezoelectric film, and the cross-sectional area is slightly larger than the area of the piezoelectric film;

[0022] The upper surface has a groove or a protrusion, and the cross-sectional shape of the groove or the protrusion is the same as that of the upper surface, and the area is smaller than that of the piezoelectric film;

[0023] The lower surface is a groove or a plane, and is in contact with the sensitive surface of the absolute pressure sensor.

[0024] Based on the further improvement of the above method, the upper surface of the second transmission component is in contact with the piezoelectric film, and the fixing method is that the piezoelectric film covers the groove or the protrusion on the upper surface and is fixed by edge bonding.

[0025] Based on the further improvement of the above method, the second transmission component has a regular shape or a combination of regular shapes, wherein,

[0026] The regular shape is a cylinder, a cube, a cuboid, or a polygon with two parallel surfaces;

[0027] The combination of regular shapes is a plurality of regular shapes of the same type or different types, which are fixed as a stable whole by axial center symmetry, edge alignment, and surface contact.

[0028] Based on the further improvement of the above method, the single mechanical wave sensing module further comprises a fixing component coupled and fixed with the second transmission component, and the sensitive surface of the absolute pressure sensor is in slight force contact with the lower surface of the second transmission component.

[0029] Based on the further improvement of the above method, after the signal decomposition module decomposes the respiratory wave, the ultra-low frequency heart motion signal, the heart vibration signal, and the heart and lung sound signal, it further comprises the following steps: performing single cycle processing on the respiratory wave, the ultra-low frequency heart motion signal, the heart vibration signal, and the heart and lung sound signal to obtain three synchronous single cycle signals that synchronously map the heart vibration frequency within a certain respiratory duration.

[0030] Based on the further improvement of the above method, the single cycle processing of the respiratory wave, the ultra-low frequency heart motion signal, the heart vibration signal, and the heart and lung sound signal to obtain three synchronous single cycle signals that synchronously map the heart vibration frequency within a respiratory cycle, comprises:

[0031] The peak of the respiratory wave is obtained by searching the peak function, and the super low frequency cardiac signal, the heart shock signal and the heart-lung sound signal are cut off according to the peak position of the respiratory wave, so that multiple segments of the super low frequency cardiac vibration signal, the heart shock signal and the heart-lung sound signal are obtained.

[0032] For each segment, the peak of the super low frequency cardiac signal is extracted by the peak searching algorithm, and the super low frequency cardiac signal, the heart shock signal and the heart-lung sound signal are cut off according to the peak position, so that multiple single period super low frequency cardiac signals, heart shock signals and heart-lung sound signals with different lengths are obtained.

[0033] The segments of the single period super low frequency cardiac signal, the heart shock signal and the heart-lung sound signal with the same number of heart vibrations are selected, and the period average value of each segment is calculated as the period length of the equal-length segment of the single period super low frequency cardiac signal, the heart shock signal and the heart-lung sound signal.

[0034] The selected segments of the super low frequency cardiac signal, the heart shock signal and the heart-lung sound signal with different lengths are processed by the cubic spline interpolation method to obtain the equal-length single period signals of the corresponding super low frequency cardiac signal, the heart shock signal and the heart-lung sound signal.

[0035] The equal-length single period signals of the super low frequency cardiac signal, the heart shock signal and the heart-lung sound signal are time-domain averaged to obtain the single period signals of the synchronized super low frequency cardiac signal, the heart shock signal and the heart-lung sound signal.

[0036] Compared with the prior art, the present application has the following advantages:

[0037] 1. The four frequency band heart-lung mechanical waves are simultaneously collected on a single sensor, which can comprehensively reflect the mechanical vibration information of the heart and lungs.

[0038] 2. On the basis of multi-frequency band heart-lung vibration detection, an absolute pressure sensor is added to collect static pressure signals to reflect the adhesion degree of the sensor and the human body, and to quantify the process, so that the detection of multi-frequency band mechanical waves is more accurate and efficient.

[0039] 3. The adopted laminated structure can effectively transmit the vibration received by the piezoelectric film to the absolute pressure sensor below and realize synchronous signal collection.

[0040] 4. The deformation displacement design is added to the second transmission part, which effectively improves the collection sensitivity of the piezoelectric film and provides guarantee for the signal quality of multi-frequency band mechanical waves.

[0041] The technical solutions in the present application can be combined with each other to realize more preferred combination solutions. Other features and advantages of the present application will be described in the following description, and some advantages will become apparent from the description, or will be understood by those skilled in the art through implementation of the present application. The objects and other advantages of the present application can be realized and obtained through the contents particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0042] The accompanying drawings are included to provide a further understanding of the present application, and are incorporated herein and constitute a part of the detailed description. The drawings illustrate embodiments of the present application and, together with the description, serve to explain the principles of the present application. In the drawings:

[0043] Figure 1 is a schematic diagram of a collection device system design provided by the present application.

[0044] Figure 2 is a structural schematic diagram of a single mechanical wave sensing module of an embodiment of the present application.

[0045] Figure 3 is a piezoelectric signal collected and a breathing wave, an ultra-low frequency heart signal, a heart shock signal and a heart-lung sound signal extracted in an embodiment of the present application.

[0046] Figure 4 is an absolute pressure sensor signal collected and a static pressure value extracted in an embodiment of the present application. DETAILED DESCRIPTION

[0047] The preferred embodiments of the present application will be specifically described below in conjunction with the drawings, wherein the drawings constitute a part of the present application and serve to explain the principles of the embodiments of the present application, but are not used to limit the scope of the present application.

[0048] The technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0049] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0050] The present application will be further described below in conjunction with specific embodiments, but is not limited by the embodiments.

[0051] The present example is realized by the following technical solutions:

[0052] As Figure 1As shown in the figure, a single-sensor-based heart-lung multi-band mechanical wave detection device includes a single mechanical wave sensing module, a signal receiving circuit, and a multi-band signal extraction module; the single mechanical wave sensing module synchronously collects the electric signals of the piezoelectric film and the absolute pressure sensor, and adopts a first transmission component, a piezoelectric film, a second transmission component, and an absolute pressure sensor arranged in sequence; the signal receiving circuit includes a signal amplification module, an analog-digital conversion module, and a signal output module, which is used to amplify and analog-digital convert the electric signals collected by the single mechanical wave sensing module, and transmit the digital signals to the multi-band signal extraction module; the signal decomposition module in the multi-band signal extraction module decomposes the digital piezoelectric signal to obtain a respiratory wave, an ultra-low frequency heart signal, a heart vibration signal, and a heart-lung sound signal, and the signal filtering module processes the digital absolute pressure signal to obtain a static pressure value.

[0053] Further, as shown in the figure, the structure of the single mechanical wave sensing module adopts a fixed arrangement in sequence, and from the contact with the human body to the outside, it is in sequence: a first transmission component, a piezoelectric film, a second transmission component, an absolute pressure sensor, and a fixed component. Figure 2

[0054] Further, the first transmission component specifically is:

[0055] It is made of soft insulating material suitable for contacting the human body and having good mechanical wave conduction ability;

[0056] It adopts a regular shape with parallel upper and lower surfaces, wherein the upper surface contacts the human body, and the lower surface contacts the piezoelectric film;

[0057] The lower surface has the same shape as the piezoelectric film, and the cross-sectional area is slightly smaller than that of the piezoelectric film.

[0058] Further, the first transmission component and the piezoelectric film adopt a center alignment mode, and the edges are bonded and fixed.

[0059] Specifically, the first transmission component is made of soft insulating material suitable for contacting the human body and having good mechanical wave conduction ability, the main purpose of which is to avoid human discomfort caused by wearing and to avoid the loss of the electric signal converted by the sensor from the collected mechanical vibration and pressure.

[0060] The first transmission component needs to adopt a regular shape with parallel upper and lower surfaces, and is preferably a cylinder, a square, a cuboid, an elliptical cylinder, or a polygon, wherein the two parallel surfaces can be of the same shape or different shapes, but for the purpose of wearing comfort, the surface in contact with the human body is preferably of a shape without edges and corners, such as a circle, an ellipse, or a polygon with rounded corners; based on the purpose of fixing with the piezoelectric film, the other surface must be consistent with the shape of the piezoelectric film, and the cross-sectional area is slightly smaller than that of the piezoelectric film, so that the edges of the piezoelectric film and the contact surface of the first transmission component are bonded and fixed.​

[0061] Preferably, the first transmission component is in the shape of a cylinder, cuboid or square, with a cross-sectional area slightly smaller than that of the piezoelectric film, and is made of elastic ethylene-vinyl acetate copolymer (EVA), thermoplastic elastomer (TPE), polyurethane (PU) or silicone rubber, so as to effectively transmit the vibration of the human chest wall to the underlying piezoelectric film.

[0062] Preferably, the first transmission component and the underlying piezoelectric film are adhered by means of solid glue, double-sided tape, hot melt glue, sealant or soluble adhesive, etc., to play a stabilizing role.

[0063] Preferably, the piezoelectric film is in the shape of a square, rectangle or circle, and is made of polyvinylidene fluoride (PVDF), vinylidene fluoride-trifluoroethylene copolymer (VDF-TrFE), lead zirconate titanate (PZT) or zirconium aluminum oxide (ZAO).

[0064] Further, the second transmission component is made of a hard insulating material with good mechanical wave conduction ability, is in the shape of a regular shape with parallel upper and lower surfaces, the upper surface is in the same shape as the piezoelectric film, has a cross-sectional area slightly larger than that of the piezoelectric film, and has a groove or protrusion in the same shape as the piezoelectric film and with an area slightly smaller than that of the piezoelectric film; the lower surface is a groove or a plane, and is in contact with the sensitive surface of the absolute pressure sensor.

[0065] The main function of the second transmission component is to stably transmit the mechanical wave conducted by the first transmission component and the piezoelectric film to the underlying absolute pressure sensor, and to contact and fix other components to form an integral structure.

[0066] The upper surface of the second transmission component is fixed with the piezoelectric film, and the piezoelectric film is fixed with the first transmission component, so that the three form a stable whole. The upper surface needs to be in the same shape as the piezoelectric film and has an area slightly larger than that of the piezoelectric film, and the two can be fixed by edge bonding; the surface of the second transmission component in contact with the piezoelectric film is designed with a groove or protrusion, in order to increase the deformation displacement of the piezoelectric film. When the human body vibration wave is conducted by the first transmission component, the groove or protrusion with an area smaller than that of the piezoelectric film causes a gap between the piezoelectric film and the second transmission component, which can cause the oscillation change of the surface of the piezoelectric film, so that the piezoelectric film is more likely to generate a piezoelectric signal, and the detection of the vibration signal is more sensitive.

[0067] The lower surface of the second transmission component needs to be in contact with the absolute pressure sensor, and the two are coupled and fixed as a whole. The shape of the lower surface is related to the absolute pressure sensor. According to the shape and type of the absolute pressure sensor, the lower surface can be designed as a groove or a plane. Preferably, the lower surface is designed as a groove, which can accommodate the sensitive surface of the absolute pressure sensor and form a fixed structure together. The inner surface of the groove needs to be in direct contact with the sensitive surface of the absolute pressure sensor. At the same time, the shape of the sensitive surface of the absolute pressure sensor may be different from the piezoelectric film. For example, if the piezoelectric film is circular, the sensitive surface of the absolute pressure sensor is square. Therefore, the upper and lower surfaces of the second transmission component can be designed in different shapes, but need to be symmetrical around the center axis to ensure stable transmission of vibration waves. In addition, the second transmission component can be a single member or a combination of two members, such as a cylinder and a cube forming a whole, the upper surface of the cylinder fixed with the piezoelectric film, and the lower surface of the cube coupled and fixed with the absolute pressure sensor, or a combination of two or more identical members. It should be noted that the above is only one example of the technical point in the present application.

[0068] The second transmission component and the absolute pressure sensor are fixed by contact coupling.

[0069] Preferably, the edge is fixed by magic tape bonding, buckle fixing, screw fixing, or a shell that can accommodate both and form a fixed structure.

[0070] Further, the second transmission component is a regular shape or a combination of regular shapes, wherein,

[0071] The regular shape is a cylinder, a cube, a cuboid, or a polygon with two parallel surfaces;

[0072] The combination of regular shapes is a plurality of regular shapes of the same type or different types, which are fixed as a stable whole with axis center symmetry, edge alignment, and surface contact.

[0073] Preferably, the second transmission component is a cuboid, a cylinder, or a cube, and the material is 3D printing material such as polylactic acid (PLA), acrylonitrile-butadiene-styrene copolymer (ABS), polyethylene terephthalate (PETG), thermoplastic polyurethane (TPU), or nylon.

[0074] Further, the contact and fixing method between the upper surface of the second transmission component and the piezoelectric film is that the piezoelectric film covers the groove or protrusion on the upper surface, and the edges are bonded and fixed.

[0075] Preferably, the upper surface of the second transmission component is pasted with the piezoelectric film by means of solid glue, double-sided tape, hot melt glue, sealant or soluble adhesive; the lower surface is a groove or a flat surface for contact coupling with the sensitive surface of the absolute pressure sensor, as shown in the following embodiment. Figure 2 In the embodiment shown, the lower surface of the second transmission component is a groove that covers the absolute pressure sensor.

[0076] Preferably, the absolute pressure sensor is a strain gauge, piezoresistive or capacitive sensor that can extract static pressure information to quantify the adhesion of the sensor to the chest wall.

[0077] Preferably, the fixing component is rectangular, square or circular in shape and made of PCB, metal or plastic.

[0078] Further, the single mechanical wave sensing module further comprises a fixing component that is coupled and fixed with the second transmission component, and the sensitive surface of the absolute pressure sensor is in slight force contact with the lower surface of the second transmission component.

[0079] Preferably, the connection between the absolute pressure sensor and the fixing component is by welding or pasting with solid glue, double-sided tape, hot melt glue, sealant or soluble adhesive, which serves to stabilize.

[0080] Further, the piezoelectric film and the absolute pressure sensor signal are amplified by respective signal amplification circuits, and then simultaneously converted and sampled by analog-to-digital conversion, and the converted two-way digital signals are synchronously transmitted to the multi-band signal extraction module for processing.

[0081] Further, the multi-band signal extraction module comprises a signal decomposition part for piezoelectric signals and a signal filtering part for absolute pressure signals.

[0082] Preferably, the signal decomposition processing includes band-pass filter, EMD decomposition or wavelet decomposition to obtain respiratory waves, ultra-low frequency heart signals, heart vibration signals and heart-lung sound signals from low to high frequencies.

[0083] Preferably, the signal filtering processing includes high-pass filter, low-pass filter and band-stop filter processing to obtain static pressure signals.

[0084] Further, the digital piezoelectric signal is filtered and signal-decomposed into continuous four-way respiratory waves, ultra-low frequency heart signals, heart vibration signals and heart-lung sound signals, and further comprises the following steps: single-cycle processing of the respiratory waves, ultra-low frequency heart signals, heart vibration signals and heart-lung sound signals to obtain three-way synchronous single-cycle signals that synchronously map the heart vibration frequency within a certain respiratory duration.

[0085] Further, according to the peak and trough of the respiratory wave, a segment of the cardiac vibration signal is intercepted, wherein one respiratory wave trough or peak contains multiple cardiac vibration periods.

[0086] For a length of respiratory wave, the respiratory wave peak BT is extracted by a peak searching function i , i = 1, 2, 3,.... n, n is the number of respiratory waves. Because the ultra-low frequency cardiac signal, the cardiac vibration signal, the heart and lung sound signal are related to the cardiac vibration period, therefore, the segments of the ultra-low frequency cardiac signal ULF_SCG i , the cardiac vibration signal SCG i and the heart and lung sound signal PCG i can be obtained by peak truncation.

[0087] For the signal of each segment, the peak US_T of the ultra-low frequency cardiac signal is extracted by a peak searching algorithm j , j = 1, 2, 3,.... m, m is the number of cardiac vibration waves, according to the peak value, the segments of the ultra-low frequency cardiac vibration signal ULF_SCG i , the cardiac vibration signal SCG j and the heart and lung sound signal PCG j are truncated, and multiple single period segments with different lengths are formed, from which m single period segments are selected, and the period average of the above m single period segments is taken as the period length T of the equal length segment:

[0088]

[0089] Wherein, T j is the period of each unequal length segment.

[0090] The cubic spline interpolation method is used to process the m unequal length signals to obtain multiple equal length period signals:

[0091] x SCG_j = f spline (SCG j , T)

[0092] x PCG_j = f spline (PCG j , T)

[0093] x ULF_SCG_j = f spline (ULF_SCG j , T)

[0094] Wherein, x SCG_j , x PCG_j , x ULF_SCG_j are equal length single period signal segments of the cardiac vibration signal, the heart and lung sound signal and the ultra-low frequency cardiac vibration signal respectively.

[0095] The single period signals of the synchronous heart vibration signal, the heart-lung sound signal and the ultra-low frequency heart vibration signal are obtained by time domain averaging of the processed isometric multi-period signals respectively:

[0096]

[0097]

[0098]

[0099] wherein x SCG_ave , x PCG_ave , x ULF_SCG_ave are the single period signals corresponding to the synchronous heart vibration signal, the heart-lung sound signal and the ultra-low frequency heart vibration signal respectively, and the period is T.

[0100] Preferably, the continuous static pressure signal obtained is calculated to obtain an average pressure signal as the static pressure signal value in the state:

[0101]

[0102] wherein P represents the static pressure signal in the state, and P i is the continuous static pressure signal collected.

[0103] According to the pressure signal-pressure value relationship curve in the official test data document of the absolute pressure sensor, the pressure value (N) in the signal can be determined:

[0104] N = f (P)

[0105] N is the static pressure value in the state, and f is the pressure signal-pressure value relationship function of the absolute pressure sensor, which is determined by the specific sensing principle of the absolute pressure sensor.

[0106] According to the pressure value, the fitting degree of the chest wall can be divided into different grades by setting a threshold. We select the pressure range of 1-2N as the appropriate pressure interval, and the fitting degree in the pressure interval less than 1N is judged as not normally fitted, and the fitting degree in the pressure value interval greater than 2N is judged as too close:

[0107]

[0108] Degree represents the fitting degree of the sensor and the human chest wall in the state, S indicates that the fitting degree is not close enough, A indicates that the fitting degree is appropriate, and L indicates that the fitting degree is too close.

[0109] The workflow of the embodiment is as follows:

[0110] The transmission structure 1 contacts the human chest wall, transmits the mechanical wave vibration of the heart and lung to the piezoelectric film, and generates electric charge through deformation, thereby forming an analog piezoelectric signal.

[0111] The vibration is continuously transmitted to the sensitive surface of the absolute pressure sensor through the second transmission component, thereby converting the vibration into electric energy and forming an analog absolute pressure signal.

[0112] The two signals are transmitted to the next stage for signal processing through signal amplification, analog-to-digital conversion and signal transmission.

[0113] The digital piezoelectric signal is decomposed to obtain a respiratory wave signal, an ultra-low frequency heart signal, a heart shock signal and a heart-lung sound signal with a frequency from low to high.

[0114] The digital absolute pressure sensor signal is filtered to obtain a static pressure signal.

[0115] The static pressure signal can quantify the different degrees of adhesion of the single mechanical wave sensor and the chest wall, and reflect the differences in the multi-frequency vibration of the heart under different adhesion degrees.

[0116] Those skilled in the art can understand that all or part of the processes of the above-mentioned embodiments can be completed by a computer program instructing related hardware, and the program can be stored in a computer readable storage medium, wherein the computer readable storage medium is a disk, an optical disk, a read-only memory or a random access memory, etc.

[0117] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A single-sensor-based cardiopulmonary multi-band mechanical wave detection device, characterized in that, The single mechanical wave sensing module, the signal receiving circuit and the multi-frequency band signal extraction module are included. The single mechanical wave sensing module is used for synchronously collecting piezoelectric signals and absolute pressure signals at the heart-lung chest cavity position, and includes a first transmission component, a piezoelectric film, a second transmission component and an absolute pressure sensor which are sequentially stacked. The signal receiving circuit is used for amplifying and analog-digital converting the piezoelectric signals and the absolute pressure signals collected by the single mechanical wave sensing module to obtain digital piezoelectric signals and digital absolute pressure signals. The multi-frequency band signal extraction module includes a signal decomposition module and a signal filtering module. The signal decomposition module is used for decomposing the digital piezoelectric signals to obtain a respiratory wave, an ultra-low frequency heart motion signal, a heart vibration signal and a heart-lung sound signal. The signal filtering module is used for filtering the digital absolute pressure signals to obtain a static pressure value, and for performing single cycle processing on the respiratory wave, the ultra-low frequency heart motion signal, the heart vibration signal and the heart-lung sound signal to obtain a single cycle signal of the three synchronously mapped ultra-low frequency heart motion signals, heart vibration signals and heart-lung sound signals in a respiratory cycle. The peak of the respiratory wave is obtained by a peak searching function. The ultra-low frequency heart vibration signal, the heart vibration signal and the heart-lung sound signal are obtained by cutting off the ultra-low frequency heart motion signal, the heart vibration signal and the heart-lung sound signal according to the peak position of the respiratory wave. For each of the segments, the peak of the extracted ultra-low frequency heart motion signal is obtained by a peak searching algorithm. The ultra-low frequency heart motion signal, the heart vibration signal and the heart-lung sound signal are cut off according to the peak position of each segment to obtain a plurality of single cycle ultra-low frequency heart motion signals, heart vibration signals and heart-lung sound signals with different lengths. The segments of the single cycle ultra-low frequency heart motion signal, the heart vibration signal and the heart-lung sound signal with the same number of heart vibrations are selected. The cycle length of the equal length segments of the single cycle ultra-low frequency heart motion signal, the heart vibration signal and the heart-lung sound signal is obtained based on the cycle of each segment. The equal length single cycle signals of the ultra-low frequency heart motion signal, the heart vibration signal and the heart-lung sound signal are obtained by processing the selected segments of the ultra-low frequency heart motion signal, the heart vibration signal and the heart-lung sound signal with different lengths by using a cubic spline interpolation method. The single cycle signals of the ultra-low frequency heart motion signal, the heart vibration signal and the heart-lung sound signal are obtained by time domain averaging of the equal length single cycle signals of the ultra-low frequency heart motion signal, the heart vibration signal and the heart-lung sound signal.

3. The single-sensor based multi-frequency band mechanical wave detection device for cardiopulmonary system according to claim 2, wherein, 2. The heart-lung multi-frequency band mechanical wave detection device based on a single sensor according to claim 1, wherein the first transmission component is used to transmit the vibration wave of the human chest cavity to the piezoelectric film. The piezoelectric film is used to detect the analog piezoelectric signal generated by the pressure transmitted by the first transmission component. The second transmission component is used to fix the piezoelectric film and the absolute pressure sensor as an intermediate part and transmit the pressure to the absolute pressure sensor. The absolute pressure sensor is used to detect the analog absolute pressure signal generated by the pressure. The first transmission component is specifically made of a soft insulating material suitable for contacting the human body and having good mechanical wave conduction ability. The upper surface is parallel to the lower surface, the upper surface contacts the human body, and the lower surface contacts the piezoelectric film. The lower surface has the same shape as the piezoelectric film, and the cross-sectional area is slightly smaller than the area of the piezoelectric film.

4. The single-sensor based multi-frequency band mechanical wave detection device for cardiopulmonary system according to claim 3, wherein, The lower surface of the first transmission component is aligned with the center of the piezoelectric film, and the edges are fixed by adhesion.

5. The single-sensor based multi-frequency band mechanical wave detection device for cardiopulmonary system according to claim 3, wherein, The second transmission component is specifically: Made of hard insulating material with good mechanical wave conduction ability; The upper surface is parallel to the lower surface, the upper surface contacts the piezoelectric film, and the lower surface contacts the absolute pressure sensor. The upper surface has the same shape as the piezoelectric film, and the cross-sectional area is slightly larger than the area of the piezoelectric film. The upper surface has a groove or a protrusion, and the cross-sectional shape of the upper surface groove or protrusion is the same as the upper surface, and the area is smaller than the area of the piezoelectric film. The lower surface is a groove or a plane, and contacts the sensitive surface of the absolute pressure sensor.

6. The single-sensor based multi-frequency band mechanical wave detection device for cardiopulmonary system according to claim 3, wherein, The upper surface of the second transmission component contacts and fixes the piezoelectric film, and the edges are fixed by adhesion.

7. The single-sensor based multi-frequency band mechanical wave detection device for cardiopulmonary system according to claim 5, wherein, The second transmission component has a regular shape or a combination of regular shapes, wherein The regular shape is a cylinder, a cube, or a cuboid. The combination of regular shapes is a combination of multiple regular shapes of the same type or different types, which are fixed as a stable whole by axis center symmetry, edge alignment, and surface contact.

8. The single-sensor based multi-frequency band mechanical wave detection device for cardiopulmonary system according to claim 2, wherein, The single mechanical wave sensing module further comprises a fixing component, which is coupled and fixed with the second transmission component, and the sensitive surface of the absolute pressure sensor is in slight force contact with the lower surface of the second transmission component.

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