Cardiopulmonary multi-band mechanical wave detection device based on single sensor

Abstract

The invention relates to a cardiopulmonary multi-band mechanical wave detection device based on a single sensor, belongs to the technical field of medical instruments, and relates to a cardiopulmonary signal detection technology. A single mechanical wave sensor formed by fixedly stacking a first transmission part, a piezoelectric film, a second transmission part and an absolute pressure sensor synchronously and stably collects electric signals, caused by chest wall vibration, of the piezoelectric film and the absolute pressure sensor, and the electric signals are processed through a signal amplification circuit and transmitted to a multi-frequency-band signal extraction module; the digital piezoelectric signals are decomposed to obtain respiratory waves, ultralow-frequency cardiac waves, cardiac vibration signals and heart and lung sound signals, and the digital absolute pressure signals are filtered to obtain static pressure values which reflect the chest wall fitting degree, so that multi-band mechanical vibration information of the heart and the lung is synchronously extracted on a single sensor; and an efficient and portable mode is provided for knowing the cardiopulmonary activity and state.

Description

Technical Field

[0001] The present invention belongs to the technical field of medical devices, relates to cardiopulmonary signal detection technology, and particularly relates to a single-sensor-based cardiopulmonary multi-band mechanical wave detection device. Background Art

[0002] The movements of the heart and lungs are inseparable. Cardiopulmonary diseases are one of the important factors threatening people's lives and health globally, and the trend of younger age is becoming increasingly prominent. Daily monitoring of the heart and lungs and early warning of diseases are key tasks in medicine, which pose new requirements for sensors for detecting the heart and lungs. Traditional sensing technologies include single detection of cardiopulmonary mechanical information such as heart sounds, lung sounds auscultation, respiratory waves (chest wall expansion and contraction caused by breathing), and seismocardiogram signals (SCG, local chest wall vibration caused by heartbeat). Cardiopulmonary movement is a complex movement that contains mechanical waves of different frequency components. However, the above single sensing technologies can only reflect a certain frequency band of cardiopulmonary movement. To comprehensively reflect the mechanical wave movement of the heart and lungs, it is necessary to collect the signals of the above multiple sensors. At the same time, different degrees of fitting between the sensor and the human chest wall will affect the effect of the collected mechanical waves, changing the shape and quality of the signal waveform. And in the current cardiopulmonary vibration monitoring technology, static pressure is not integrated to reflect the fitting degree between the sensor and the human chest wall. To fully reflect the mechanical activity information of the heart and lungs through the vibration waveform, it is necessary to extract static pressure.

[0003] In the implementation process of the sensor, the broadband characteristics of the piezoelectric film show the potential to simultaneously detect mechanical vibrations from low frequency to high frequency. This makes it possible to obtain the above multi-band cardiopulmonary vibration signals on a single sensor. The present invention proposes a single-sensor-based cardiopulmonary multi-band mechanical wave detection device based on a piezoelectric film, which can simultaneously extract respiratory waves, ultra-low frequency cardiac signals, seismocardiogram signals, and cardiopulmonary sound signals. To reflect the fitting degree between 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 quantification of the fitting degree. The present invention provides an efficient and portable way to comprehensively understand cardiopulmonary mechanical vibration information to reflect cardiopulmonary activities and states, and can be further applied to wearable and daily portable devices for the heart and lungs, providing the possibility for early detection and timely treatment of cardiopulmonary abnormalities, and helping to avoid the increase of medical costs and the waste of medical resources. Summary of the Invention

[0004] To solve the above problems, the present invention provides a single-sensor-based cardiopulmonary multi-band mechanical wave detection device, which synchronously collects piezoelectric signals and absolute pressure signals at the cardiopulmonary thoracic position, and further extracts the piezoelectric signals into respiratory waves, ultra-low frequency cardiac signals, seismocardiogram signals, and cardiopulmonary sound signals, reflecting the mechanical vibration information of the heart and lungs in multiple frequency bands.

[0005] On the one hand, an embodiment of the present invention provides a cardiopulmonary multi-band mechanical wave detection device based on a single sensor, including a single mechanical wave sensing module, a signal receiving circuit, and a multi-band signal extraction module. Among them,

[0006] The single mechanical wave sensing module is used to synchronously collect piezoelectric signals and absolute pressure signals at the cardiopulmonary thoracic position, and includes a first transmission component, a piezoelectric film, a second transmission component, and an absolute pressure sensor that are sequentially stacked;

[0007] The signal receiving circuit is used to amplify and perform analog-to-digital conversion on the piezoelectric signal and the absolute pressure signal collected by the single mechanical wave sensing module to obtain a digital piezoelectric signal and a digital absolute pressure signal;

[0008] The multi-band signal extraction module includes a signal decomposition module and a signal filtering module. Among them, the signal decomposition module is used to decompose the digital piezoelectric signal to obtain a respiratory wave, an ultra-low frequency cardiac signal, a heart shock signal, and a cardiopulmonary sound signal, and the signal filtering module is used to filter the digital absolute pressure value signal to obtain a static pressure value.

[0009] Based on a further improvement of the above method, the first transmission component is used to transmit the vibration wave of the human chest to the piezoelectric film;

[0010] The piezoelectric film is used to detect the analog piezoelectric signal generated by the pressure transmitted by the first transmission component;

[0011] The second transmission component is used as an intermediate member to fix the piezoelectric film and the absolute pressure sensor and transmit the pressure to the absolute pressure sensor;

[0012] The absolute pressure sensor is used to detect the analog absolute pressure signal generated by the pressure.

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

[0014] Made of a soft insulating material suitable for contacting the human body and having good mechanical wave conduction ability;

[0015] Adopts a regular shape with parallel upper and lower surfaces, where 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 the cross-sectional area is slightly smaller than the area of the piezoelectric film.

[0017] Based on a further improvement of the above method, the lower surface of the first transmission component and the piezoelectric film are centered and adhesively fixed at the edges.

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

[0019] It is made of a hard insulating material with good mechanical wave conduction ability;

[0020] It adopts a regular shape with parallel upper and lower surfaces, where the upper surface contacts the piezoelectric film and the lower surface contacts 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 that of the piezoelectric film;

[0022] The upper surface has grooves or protrusions, where the cross-sectional shape of the upper surface grooves or protrusions 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 flat surface, which contacts the sensitive surface of the absolute pressure sensor.

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

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

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

[0027] The combination of regular shapes is a stable whole formed by multiple regular shapes of the same or different types that are axisymmetric, edge-aligned, and surface-contact-fixed.

[0028] Based on the further improvement of the above method, the single mechanical wave sensing module further includes 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.

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

[0030] Based on the further improvement of the above method, the single-cycle processing of the respiratory waves, ultra-low frequency cardiac signals, heart shock signals and cardiorespiratory sound signals to obtain single-cycle signals of three-way synchronous ultra-low frequency cardiac signals, heart shock signals and cardiorespiratory sound signals that synchronously map the cardiac vibration frequency within a respiratory cycle includes:

[0031] Peak detection is performed on the respiratory wave through a peak detection function to obtain the peaks of the respiratory wave; based on the peak positions of the respiratory wave, the ultra-low frequency cardiac signal, the heart shock signal, and the cardiorespiratory sound signal are truncated to obtain multiple segments of the ultra-low frequency cardiac vibration signal, the heart shock signal, and the cardiorespiratory sound signal;

[0032] For each of the said segments, the peaks of the ultra-low frequency cardiac signal are extracted through a peak detection algorithm, and then the ultra-low frequency cardiac signal, the heart shock signal, and the cardiorespiratory sound signal are each truncated according to the peak positions to obtain multiple single-cycle ultra-low frequency cardiac signals, heart shock signals, and cardiorespiratory sound signals with different lengths;

[0033] Segments of the single-cycle ultra-low frequency cardiac signal, the heart shock signal, and the cardiorespiratory sound signal that are the same as the number of heart vibrations are selected, and the average value of the periods based on the periods of the above-mentioned segments is obtained as the period length of the equal-length segments of the single-cycle ultra-low frequency cardiac signal, the heart shock signal, and the cardiorespiratory sound signal;

[0034] The segments of the unequal-length ultra-low frequency cardiac signal, the heart shock signal, and the cardiorespiratory sound signal that are selected are processed using the cubic spline interpolation method to respectively obtain the equal-length single-cycle signals of the corresponding ultra-low frequency cardiac signal, the heart shock signal, and the cardiorespiratory sound signal;

[0035] Time domain averaging is performed on the equal-length single-cycle signals of the ultra-low frequency cardiac signal, the heart shock signal, and the cardiorespiratory sound signal to obtain the single-cycle signals of the synchronized ultra-low frequency cardiac signal, the heart shock signal, and the cardiorespiratory sound signal.

[0036] Compared with the prior art, the present invention achieves the following beneficial effects:

[0037] 1. It is possible to simultaneously collect cardiorespiratory mechanical waves in four frequency bands on a single sensor, which can comprehensively reflect the mechanical vibration information of the heart and lungs.

[0038] 2. On the basis of multi-band cardiorespiratory vibration detection, an absolute pressure sensor is added to collect static pressure signals to reflect the fitting degree between the sensor and the human body, and this process is quantified, making the detection of multi-band mechanical waves more accurate and efficient.

[0039] 3. The adopted stacked structure can effectively transfer the vibration received by the piezoelectric film to the absolute pressure sensor below and achieve synchronous signal acquisition.

[0040] 4. A deformation displacement design is added to the second transmission component, effectively improving the acquisition sensitivity of the piezoelectric film and providing a guarantee for the signal quality of multi-band mechanical waves.

[0041] In the present invention, the above technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent specification, and some advantages will be obvious from the specification or can be understood by implementing the present invention. The objectives and other advantages of the present invention can be realized and obtained from the content specifically pointed out in the specification and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The drawings are only for the purpose of showing specific embodiments and are not considered to be a limitation of the present invention. Throughout the drawings, the same reference numerals represent the same components.

[0043] Figure 1 It is a schematic diagram of the system design of the acquisition device provided by the present invention.

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

[0045] Figure 3 It is the piezoelectric signal acquired according to an embodiment of the present invention and the extracted respiratory wave, ultra-low frequency cardiac signal, heart shock signal, and cardio-pulmonary sound signal.

[0046] Figure 4 It is the absolute pressure sensor signal acquired according to an embodiment of the present invention and the extracted static pressure value. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0047] The following will specifically describe the preferred embodiments of the present invention with reference to the drawings. The drawings form a part of this application and are used together with the embodiments of the present invention to explain the principles of the present invention, rather than to limit the scope of the present invention.

[0048] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

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

[0050] The following will further illustrate the present invention with specific embodiments, but it is not a limitation of the present invention.

[0051] This example is implemented through the following technical solutions:

[0052] As Figure 1As shown in the figure, a single-sensor-based multi-band mechanical wave detection device for cardiopulmonary function 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 electrical 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 that are sequentially stacked. The signal receiving circuit includes a signal amplification module, an analog-to-digital conversion module, and a signal output module, which are used to amplify and perform analog-to-digital conversion on the electrical 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 respiratory waves, ultra-low frequency cardiac signals, cardiac shock signals, and cardiopulmonary sound signals, and the signal filtering module processes and filters the digital absolute pressure signal to obtain the static pressure value.

[0053] Further, as Figure 2 shown, the structure of the single mechanical wave sensing module adopts a fixed sequential stacking arrangement. From the side contacting the human body outward, they are: a first transmission component, a piezoelectric film, a second transmission component, an absolute pressure sensor, and a fixing component.

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

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

[0056] adopts a regular shape with parallel upper and lower surfaces. Among them, 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 the area of the piezoelectric film.

[0058] Further, the lower surface of the first transmission component and the piezoelectric film are centered and adhesively fixed at the edges.

[0059] Specifically, the first transmission component is made of a soft insulating material suitable for contacting the human body and having good mechanical wave conduction ability. The main purpose is to avoid discomfort to the human body during wearing and to avoid the loss of electrical signals converted by the sensor for mechanical vibration and pressure collection.

[0060] The first transmission component needs to adopt a regular shape with parallel upper and lower surfaces, preferably a cylinder, a cube, a cuboid, an ellipsoid, or a polyhedron. Among them, the two parallel surfaces can be of the same shape or different shapes. However, for the purpose of comfortable wearing, the plane contacting the human body is preferably a shape without sharp corners, such as a circle, an ellipse, or a polygon with rounded corners at the vertices; for the purpose of fixing with the piezoelectric film, the other plane must have the same shape as the piezoelectric film, and the cross-sectional area is slightly smaller than the piezoelectric film, so that the edge of the piezoelectric film and the contact surface edge of the first transmission component are adhesively fixed.

[0061] Preferably, the first transmission component is in the shape of a cylinder, a cuboid or a cube, and its cross-sectional area is slightly smaller than the area of the piezoelectric film. The material is elastic ethylene vinyl acetate copolymer (EVA), thermoplastic elastomer (TPE), polyurethane (PU) or silicone rubber, which can effectively transmit the vibration of the human chest wall to the piezoelectric film below.

[0062] Preferably, between the first transmission component and the piezoelectric film below, it is pasted by means of pasting such as solid glue, double-sided tape, hot melt adhesive, sealant or soluble adhesive to play a stabilizing role.

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

[0064] Furthermore, the second transmission component is made of a hard insulating material with good mechanical wave conduction ability. It is a regular shape with parallel upper and lower surfaces. The shape of the upper surface is the same as that of the piezoelectric film, and its cross-sectional area is slightly larger than that of the piezoelectric film, and there are grooves or protrusions, whose shape is the same as that of the piezoelectric film and the area needs to be slightly smaller than that of the piezoelectric film; the lower surface is a groove or a plane, which contacts the sensitive surface of the absolute pressure sensor.

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

[0066] The upper surface of the second transmission component is fixed to the piezoelectric film, and the piezoelectric film is fixed to the first transmission component, so the three form a stable whole. Among them, the upper surface needs to have the same shape as the piezoelectric film and the area is slightly larger than that of the piezoelectric film, and the two can be fixed by edge bonding; the design of adding grooves or protrusions on the surface of the second transmission component in contact with the piezoelectric film is to increase the deformation displacement of the piezoelectric film. When the human body vibration wave is conducted by the first transmission component, the grooves or protrusions smaller than the area of the piezoelectric film cause the gap formed between the piezoelectric film and the second transmission component to cause the oscillation change on the surface of the piezoelectric film, so that the piezoelectric film is more likely to generate piezoelectric signals and the detection of vibration signals 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 need to be coupled and fixed as a whole. The shape design 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 into a groove type or a flat type. Preferably, the lower surface is designed into a groove type. The groove needs to be able to accommodate the sensitive surface of the absolute pressure sensor and jointly form a fixed structure, and 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 that of the piezoelectric film. For example, the piezoelectric film is circular and the sensitive surface of the absolute pressure sensor is square. Therefore, the upper and lower surfaces of the second transmission component may be designed into different shapes, but they need to be axisymmetric to ensure the stable conduction of vibration waves; in addition, the second transmission component can be a single component or a combination of two components. For example, a whole composed of a cylinder and a cube, with a piezoelectric film fixed on the upper surface of the cylinder and an absolute pressure sensor coupled and fixed on the lower surface of the cube, or a combination of two or more identical components, etc. It should be noted that only one example of the present invention's solution for this technical point is described here.

[0068] The fixing method of the second transmission component and the absolute pressure sensor is contact coupling fixation.

[0069] Preferably, the edge is fixed by means of Velcro bonding, snap fixation, screw fixation, or a housing that can accommodate both parties and the fixed structure is put on the outside.

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

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

[0072] The combination of regular shapes is a stable whole formed by multiple regular shapes of the same kind or different kinds that are axisymmetric about the axis center, edge-aligned, and surface-contact fixed.

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

[0074] Furthermore, the contact 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 is fixed by bonding at the edge.

[0075] Preferably, the upper surface of the second transmission component and the piezoelectric film are pasted by means of pasting such as solid glue, double-sided tape, hot melt adhesive, 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, such as Figure 2 As shown in the lower surface of this embodiment is a groove that just covers the structure of the absolute pressure sensor, and the bottom surface of the groove on the lower surface contacts the sensitive surface of the absolute pressure sensor.

[0076] Preferably, the absolute pressure sensor is a strain type, piezoresistive or capacitive sensor, which can extract static pressure information to quantify the fitting degree between the sensor and the chest wall.

[0077] Preferably, the shape of the fixing component is rectangular, square or circular, and the material is a PCB board, a metal plate or a plastic plate.

[0078] Further, the single mechanical wave sensing module further includes a fixing component, the fixing component is fixedly coupled 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 method between the absolute pressure sensor and the fixing component is welding or pasting methods such as solid glue, double-sided tape, hot melt adhesive, sealant or soluble adhesive to play a stabilizing role.

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

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

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

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

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

[0085] Further, according to the peaks and troughs of the respiratory wave, segments of the cardiac vibration signal are intercepted, where one respiratory trough or peak contains multiple cardiac vibration cycles.

[0086] For a respiratory wave of a certain duration, the respiratory wave peak BT is extracted through a peak seeking function i , i = 1, 2, 3,.......n, where n is the number of respiratory waves. Since the ultra-low frequency electrocardiogram signal, heart shock signal, and cardio-pulmonary sound signal are related to the cardiac vibration cycle, therefore, the ultra-low frequency electrocardiogram signal ULF_SCG can be obtained by truncating at the peak i , the heart shock signal SCG i , and the cardio-pulmonary sound signal PCG i segments.

[0087] For the signal of each segment, the peak US_T of the ultra-low frequency electrocardiogram signal is extracted using the peak seeking algorithm j , j = 1, 2, 3,.......m, where m is the number of cardiac vibration waves. The ultra-low frequency cardiac vibration signal ULF_SCG i , the heart shock signal SCG j and the cardio-pulmonary sound signal PCG j are truncated according to the peak value to form multiple single-cycle segments of unequal lengths, and m single-cycle segments are selected from them. The average period of the above m single-cycle segments is used as the period length T of the equal-length segments:

[0088]

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

[0090] Using the cubic spline interpolation method to process the m signals of unequal lengths respectively to obtain equal-length multi-cycle 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] where x SCG_j , x PCG_j , x ULF_SCG_j are respectively the equal-length single-cycle signal segments of the heart shock signal, cardio-pulmonary sound signal, and ultra-low frequency cardiac vibration signal.

[0095] The processed multi - cycle signals of equal length are respectively subjected to time - domain averaging to obtain single - cycle signals of synchronous heart vibration signals, cardiopulmonary sound signals, and ultra - low - frequency heart vibration signals:

[0096]

[0097]

[0098]

[0099] Among them, \(x\) SCG_ave , \(x\) PCG_ave , \(x\) ULF_SCG_ave are respectively single - cycle signals corresponding to synchronous heart vibration signals, cardiopulmonary sound signals, and ultra - low - frequency heart vibration signals, and the period is \(T\).

[0100] Preferably, for the obtained continuous static pressure signal, the average pressure signal is calculated as the static pressure signal value in this state:

[0101]

[0102] Among them, \(P\) represents the static pressure signal in this state, and \(P\) i is the collected continuous static pressure signal.

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

[0104] \(N = f(P)\)

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

[0106] According to this pressure value, by setting a threshold, the fitting degree of the chest wall can be divided into different levels. We select the pressure range of \(1 - 2N\) as the appropriate pressure interval. The fitting degree in the pressure interval less than \(1N\) is judged as not fitting properly, and the fitting degree in the pressure value interval greater than \(2N\) is judged as fitting too tightly:

[0107]

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

[0109] The working process of this embodiment is as follows:

[0110] The transmission structure 1 contacts the human chest wall, transmits the cardio-pulmonary source chest wall mechanical wave vibration to the piezoelectric film, generates charges due to deformation, and thus forms an analog piezoelectric signal;

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

[0112] The two signals enter 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 respiratory wave signals, ultra-low frequency cardiac signals, heart shock signals, and cardio-pulmonary sound signals with frequencies 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 fitting degrees between the single mechanical wave sensor and the chest wall, and reflect the differences in multi-band vibrations of the heart at different fitting degrees.

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

[0117] As mentioned above, the above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A cardiopulmonary multi-band mechanical wave detection device based on a single sensor, characterized in that: It includes a single mechanical wave sensing module, a signal receiving circuit and a multi-band signal extraction module, wherein: The single mechanical wave sensor module is used to synchronously collect the piezoelectric signal and absolute pressure signal of the heart, lung and chest cavity positions, and includes a first transmission component, a piezoelectric film, a second transmission component and an absolute pressure sensor which are stacked in sequence; The signal receiving circuit is used to amplify and perform analog-to-digital conversion on the piezoelectric signal and the absolute pressure signal collected by the single mechanical wave sensor module to obtain a digital piezoelectric signal and a digital absolute pressure signal; The multi-band signal extraction module includes a signal decomposition module and a signal filtering module, wherein the signal decomposition module is used to decompose the digital piezoelectric signal to obtain respiratory waves, ultra-low frequency cardiac signals, cardiac shock signals and cardiopulmonary sound signals, and the signal filtering module is used to filter the digital absolute pressure value signal to obtain a static pressure value.

2. According to claim 1, a single-sensor cardiopulmonary multi-band mechanical wave detection device is characterized in that: A first transmission component, used for transmitting the vibration wave of the human chest cavity to the piezoelectric film; A piezoelectric film, used for detecting an analog piezoelectric signal generated by the pressure transmitted from the first transmission component; A second transmission component is used to fix the piezoelectric film and the absolute pressure sensor as an intermediate component 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.

3. According to claim 2, a single-sensor cardiopulmonary multi-band mechanical wave detection device is characterized in that: The first transmission component is specifically: Made of soft insulating material suitable for contact with the human body and with good mechanical wave conduction ability; 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; 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. According to claim 3, a single-sensor cardiopulmonary multi-band mechanical wave detection device is characterized in that: The lower surface of the first transmission component and the piezoelectric film are aligned in the center and fixed by bonding at the edges.

5. According to claim 3, a single-sensor cardiopulmonary multi-band mechanical wave detection device is characterized in that: The second transmission component is specifically: Made of hard insulating material with good mechanical wave conduction ability; A regular shape with parallel upper and lower surfaces is adopted, wherein 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, wherein the cross-sectional shape of the groove or the protrusion on the upper surface is the same as that of 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 with the sensitive surface of the absolute pressure sensor.

6. According to claim 3, a single-sensor cardiopulmonary multi-band mechanical wave detection device is characterized in that: The upper surface of the second transmission component is in contact with the piezoelectric film in a fixed manner in which the piezoelectric film covers the grooves or protrusions on the upper surface and the edges are bonded and fixed.

7. According to claim 5, a single-sensor cardiopulmonary multi-band mechanical wave detection device is characterized in that: The shape of the second transmission component is a regular shape or a combination of regular shapes, wherein: Regular shapes are cylinders, cubes, cuboids, or polygons with two parallel surfaces; The combination of regular shapes is a stable whole formed by the same or different regular shapes being symmetrical with the axis center, the edges being aligned, and the surfaces being in contact.

8. According to claim 2, a single-sensor cardiopulmonary multi-band mechanical wave detection device is characterized in that: The single mechanical wave sensing module further includes a fixing component, which is coupled and fixed to 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.

9. The cardiopulmonary multi-band mechanical wave detection device based on a single sensor according to claim 2, characterized in that: After decomposing the respiratory wave, ultra-low frequency cardiac signal, cardiac tremor signal and cardiopulmonary sound signal, the signal decomposition module further includes the following steps: single-cycle processing is performed on the respiratory wave, ultra-low frequency cardiac signal, cardiac tremor signal and cardiopulmonary sound signal to obtain single-cycle signals of three-way synchronized ultra-low frequency cardiac signal, cardiac tremor signal and cardiopulmonary sound signal that synchronously map the heart vibration frequency within one respiratory cycle.

10. The cardiopulmonary multi-band mechanical wave detection device based on a single sensor according to claim 9, characterized in that: The single-cycle processing of the respiratory wave, the ultra-low frequency cardiac signal, the cardiac tremor signal and the cardiopulmonary sound signal to obtain a single-cycle signal of three-way synchronized ultra-low frequency cardiac signal, cardiac tremor signal and cardiopulmonary sound signal that synchronously maps the cardiac vibration frequency within one respiratory cycle includes: The peak of the respiratory wave is found by using a peak finding function to obtain the peak of the respiratory wave; the ultra-low frequency cardiac signal, cardiac shock signal and cardiopulmonary sound signal are truncated according to the peak position of the respiratory wave to obtain multiple segments of the ultra-low frequency cardiac vibration signal, cardiac shock signal and cardiopulmonary sound signal; For each of the segments, the peak of the ultra-low frequency cardiac signal is extracted by a peak-finding algorithm, and then the ultra-low frequency cardiac signal, the cardiac tremor signal and the cardiopulmonary sound signal are respectively truncated according to the peak position to obtain multiple single-cycle ultra-low frequency cardiac signals, cardiac tremor signals and cardiopulmonary sound signals of different lengths; Selecting segments of a single-cycle ultra-low frequency cardiac signal, a heartbeat signal, and a heart-lung sound signal with the same number of heart vibrations, and calculating a cycle average value based on the cycles of the above segments as the cycle length of the single-cycle ultra-low frequency cardiac signal, a heartbeat signal, and a heart-lung sound signal of equal length; Using the cubic spline interpolation method to process the selected segments of ultra-low frequency cardiac signals, cardiac shock signals and cardiopulmonary sound signals of different lengths, the corresponding single-cycle signals of ultra-low frequency cardiac signals, cardiac shock signals and cardiopulmonary sound signals of equal lengths are obtained respectively; The single-cycle signals of equal length of the ultra-low frequency cardiac signal, cardiac shock signal and cardiopulmonary sound signal are averaged in the time domain to obtain the single-cycle signals of the synchronized ultra-low frequency cardiac signal, cardiac shock signal and cardiopulmonary sound signal.

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