Single sensor for detecting multi-frequency vibration of heart and lung

Abstract

The invention relates to a single sensor for detecting cardiopulmonary multi-frequency vibration, belongs to the technical field of medical instruments, and relates to a cardiopulmonary signal detection technology. A single sensor which is formed by fixedly stacking a first transmission part, a piezoelectric film, a second transmission part and an absolute pressure sensor and is used for detecting multi-frequency vibration of the heart and the lung synchronously and stably collects mechanical vibration waves of the chest wall of the human body, and the piezoelectric film is triggered to generate piezoelectric signals capable of reflecting breathing, ultralow-frequency cardiac movement, cardiac vibration and heart and lung sound information of the human body. The absolute pressure sensor is triggered to generate an absolute pressure signal reflecting the fitting degree of the chest wall and the sensor, the application effect of synchronously extracting multi-band mechanical vibration information of the heart and the lung and the fitting degree of the human body on the single sensor is achieved through a signal processing method, and an efficient and portable mode is provided for knowing the activity and state of the heart and the lung.

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 for detecting multi-frequency vibrations of the heart and lungs. 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 (expansion and contraction of the chest wall caused by breathing), and seismocardiogram signals (SCG, local vibrations of the chest wall caused by heartbeats). Cardiopulmonary movement is a complex movement that includes 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 signals from the above multiple sensors. At the same time, different degrees of adhesion 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 incorporated to reflect the adhesion 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 cardiopulmonary multi-band mechanical wave detection device based on a piezoelectric film, which can simultaneously extract respiratory waves, ultra-low frequency electrocardiogram signals, seismocardiogram signals, and cardiopulmonary sound signals. To reflect the adhesion 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 adhesion 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 waste of medical resources. Summary of the Invention

[0004] To solve the above problems, the present invention provides a single sensor for detecting multi-frequency vibrations of the heart and lungs, which synchronously collects piezoelectric signals and absolute pressure signals at the cardiopulmonary thoracic position. The piezoelectric signals can be further extracted into respiratory waves, ultra-low frequency electrocardiogram 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 single sensor for detecting multi-frequency vibrations of the heart and lungs, including a first transmission component, a piezoelectric film, a second transmission component, and an absolute pressure sensor that are sequentially stacked, where

[0006] The first transmission component is used to transmit the vibration wave of the human chest cavity to the piezoelectric film;

[0007] The piezoelectric film is used to detect the analog piezoelectric signal generated by the pressure transmitted by the first transmission component;

[0008] 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;

[0009] The absolute pressure sensor is used to detect the analog absolute pressure signal generated by the pressure.

[0010] Based on the further improvement of the above single sensor, the first transmission component is specifically:

[0011] It is made of a soft insulating material suitable for contacting the human body and having good mechanical wave conduction ability;

[0012] It 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;

[0013] 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.

[0014] Based on the further improvement of the above single sensor, the lower surface of the first transmission component and the piezoelectric film are centered and adhesively fixed at the edges.

[0015] Based on the further improvement of the above single sensor, the second transmission component is specifically:

[0016] It is made of a hard insulating material with good mechanical wave conduction ability;

[0017] 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;

[0018] 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;

[0019] The upper surface has grooves or protrusions, where the cross-sectional shape of the upper surface grooves or protrusions is the same as the upper surface, and the area is smaller than the area of the piezoelectric film;

[0020] The lower surface is a groove or a flat surface, and contacts the sensitive surface of the absolute pressure sensor.

[0021] Based on the further improvement of the above single sensor, the contact fixing method between the upper surface of the second transmission component and the piezoelectric film is that the piezoelectric film covers the upper surface groove or protrusion and is fixed by edge bonding.

[0022] Based on the further improvement of the above single sensor, the shape of the second transmission component is a regular shape or a combination of regular shapes, where,

[0023] The regular shape is a cylinder, a cube, a cuboid or a polyhedron with two parallel surfaces;

[0024] The combination of regular shapes is a stable whole formed by multiple regular shapes of the same or different types being axially symmetric, edge-aligned, and surface-contact fixed.

[0025] Based on the further improvement of the above single sensor, it 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 slightly stressed with the lower surface of the second transmission component.

[0026] A method for obtaining cardiopulmonary signals of a single sensor for detecting cardiopulmonary multi-frequency vibrations, the method includes:

[0027] Using the single sensor to detect the cardiopulmonary signals of the human body to obtain an analog absolute pressure signal;

[0028] Subjecting the analog absolute pressure signal to analog-to-digital conversion and filtering processing to obtain a static pressure value reflecting the degree of fit between the human body and the sensor;

[0029] Judging whether the static pressure value is within a preset interval. If not, adjust the degree of fit between the single sensor and the human body according to the magnitude of the static pressure value, and use the single sensor to detect the cardiopulmonary signals of the human body again until the static pressure value corresponding to the obtained analog absolute pressure signal is within the preset interval;

[0030] When the static pressure value is within the preset interval, obtain the analog piezoelectric signal of the single sensor, and subject the analog piezoelectric signal to signal amplification, analog-to-digital conversion and signal decomposition to obtain three-way synchronous ultra-low frequency cardiac signals, cardiac shock signals and cardiopulmonary sound signals that synchronously map the cardiac vibration frequency;

[0031] The preset interval refers to the pressure interval where the fit state between the human body and the single sensor meets the requirements for the effectiveness of cardiopulmonary signals..

[0032] A method for obtaining cardiopulmonary signals of a single sensor for detecting cardiopulmonary multi-frequency vibrations, the method includes:

[0033] Using the single sensor to detect the cardiopulmonary signals of the human body to obtain an analog absolute pressure signal and an analog piezoelectric signal;

[0034] The analog absolute pressure signal is subjected to analog-to-digital conversion and filtering to obtain a static pressure value reflecting the degree of fit between the human body and the sensor. The analog piezoelectric signal is amplified, subjected to analog-to-digital conversion, and decomposed to obtain three synchronous ultra-low-frequency cardiac signals, cardiac vibration signals, and cardiorespiratory sound signals that synchronously map the cardiac vibration frequency.

[0035] The three synchronous ultra-low-frequency cardiac signals, cardiac vibration signals, and cardiorespiratory sound signals obtained when the static pressure value is within a preset interval are used as effective cardiorespiratory signals.

[0036] Based on a further improvement of any one of the above two methods, the step of amplifying, performing analog-to-digital conversion, and decomposing the analog piezoelectric signal to obtain three synchronous ultra-low-frequency cardiac signals, cardiac vibration signals, and cardiorespiratory sound signals that synchronously map the cardiac vibration frequency includes:

[0037] Amplify the analog piezoelectric signal and perform analog-to-digital conversion to obtain a digital piezoelectric signal.

[0038] Decompose the digital piezoelectric signal into a respiratory wave, an ultra-low-frequency cardiac signal, a cardiac vibration signal, and a cardiorespiratory sound signal.

[0039] Peak detection is performed on the respiratory wave through a peak detection function to obtain the peak of the respiratory wave; the ultra-low-frequency cardiac signal, cardiac vibration signal, and cardiorespiratory sound signal are truncated according to the peak position of the respiratory wave to obtain multiple segments of the ultra-low-frequency cardiac signal, cardiac vibration signal, and cardiorespiratory sound signal.

[0040] For each of the segments, the peak of the ultra-low-frequency cardiac signal is extracted through a peak detection algorithm, and then the ultra-low-frequency cardiac signal, cardiac vibration signal, and cardiorespiratory sound signal are each truncated according to the peak position to obtain multiple single-cycle ultra-low-frequency cardiac signals, cardiac vibration signals, and cardiorespiratory sound signals with different lengths.

[0041] Select segments of the single-cycle ultra-low-frequency cardiac signal, cardiac vibration signal, and cardiorespiratory sound signal that are the same as the number of cardiac vibrations, and calculate the average value of the periods based on the periods of the above segments as the period lengths of the equal-length segments of the single-cycle ultra-low-frequency cardiac signal, cardiac vibration signal, and cardiorespiratory sound signal.

[0042] Use the cubic spline interpolation method to process the selected segments of the unequal-length ultra-low-frequency cardiac signal, cardiac vibration signal, and cardiorespiratory sound signal respectively to obtain corresponding equal-length single-cycle signals of the ultra-low-frequency cardiac signal, cardiac vibration signal, and cardiorespiratory sound signal.

[0043] Perform time domain averaging on the equal-length single-cycle signals of the ultra-low-frequency cardiac signal, cardiac vibration signal, and cardiorespiratory sound signal to obtain single-cycle signals of the synchronous ultra-low-frequency cardiac signal, cardiac vibration signal, and cardiorespiratory sound signal.

[0044] Compared with the prior art, the present invention achieves the following beneficial effects:

[0045] 1. It is realized that cardiopulmonary mechanical waves in four frequency bands can be simultaneously collected on a single sensor, which can comprehensively reflect the mechanical vibration information of the heart and lungs.

[0046] 2. On the basis of multi-band cardiopulmonary 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.

[0047] 3. The adopted stacked structure can effectively transfer the vibration received by the piezoelectric film to the absolute pressure sensor below and realize synchronous signal acquisition.

[0048] 4. A deformation displacement design is added to the second transmission component, effectively improving the acquisition sensitivity of the piezoelectric film and ensuring the signal quality of multi-band mechanical waves.

[0049] In the present invention, the above technical solutions can also be combined with each other to realize more preferred combination schemes. Other features and advantages of the present invention will be described in the subsequent specification, and some advantages can be made obvious from the specification or understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the content specifically pointed out in the specification and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The drawings are only for the purpose of showing specific embodiments and are not considered as limiting the present invention. Throughout the drawings, the same reference signs represent the same components;

[0051] Figure 1 is a schematic structural diagram of a single mechanical wave sensing module according to an embodiment of the present invention.

[0052] Figure 2 is a schematic system diagram of a single sensor for detecting multi-frequency cardiopulmonary vibrations according to an embodiment of the present invention.

[0053] Figure 3 is the piezoelectric signal collected according to an embodiment of the present invention and the extracted respiratory wave, ultra-low frequency cardiac signal, heart shock signal, and cardiopulmonary sound signal.

[0054] Figure 4 is the absolute pressure sensor signal collected according to an embodiment of the present invention and the extracted static pressure value. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0055] The following will specifically describe the preferred embodiments of the present invention in conjunction with 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.

[0056] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all 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 shall fall within the protection scope of the present invention.

[0057] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments may be combined with each other.

[0058] The present invention will be further described below in conjunction with specific embodiments, but it is not limited to the present invention.

[0059] Embodiment 1

[0060] As Figure 1 shown, this embodiment discloses a single sensor for detecting multi-frequency vibrations of the heart and lungs, including a first transmission component, a piezoelectric film, a second transmission component, and an absolute pressure sensor that are sequentially stacked. Among them,

[0061] The first transmission component is used to transmit the vibration wave of the human chest to the piezoelectric film;

[0062] The piezoelectric film is used to detect the analog piezoelectric signal generated by the pressure transmitted by the first transmission component;

[0063] The second transmission component is used as an intermediate to fix the piezoelectric film and the absolute pressure sensor and transmit the pressure to the absolute pressure sensor;

[0064] The absolute pressure sensor is used to detect the analog absolute pressure signal generated by the pressure.

[0065] Furthermore, the first transmission component is specifically:

[0066] Made of a soft insulating material suitable for contacting the human body and having good mechanical wave conduction ability;

[0067] 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;

[0068] 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.

[0069] Furthermore, the lower surface of the first transmission component and the piezoelectric film are centered and adhesively fixed at the edges.

[0070] Specifically, the first transmission component has a regular shape with parallel upper and lower surfaces, preferably a cylinder, a cube, a cuboid, an elliptical cylinder 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 in contact with the human body is preferably a non-angular shape, such as a circle, an ellipse, or a polygon with rounded corners at the vertices; for the purpose of fixing to the piezoelectric film, the other plane must have the same shape as the piezoelectric film and a cross-sectional area slightly smaller than that of the piezoelectric film, so that the contact surface edge of the piezoelectric film and the first transmission component can be adhesively fixed.

[0071] Preferably, the shape of the first transmission component is a cylinder, a cuboid or a cube, its cross-sectional area is slightly smaller than the area of the piezoelectric film, and 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.

[0072] Preferably, between the first transmission component and the piezoelectric film below, paste them using pasting methods such as solid glue, double-sided tape, hot melt glue, sealant or soluble adhesive to play a stabilizing role.

[0073] Preferably, the shape of the piezoelectric film is square, rectangular or circular, and the material is polyvinylidene fluoride (PVDF), vinylidene fluoride-trifluoroethylene copolymer (VDF-TrFE), lead zirconate titanate (PZT) or zirconium aluminum oxide (ZAO).

[0074] Furthermore, the second transmission component specifically is:

[0075] Made of a rigid insulating material with good mechanical wave conduction ability;

[0076] Adopt 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;

[0077] The upper surface has the same shape as the piezoelectric film and a cross-sectional area slightly larger than the area of the piezoelectric film;

[0078] The upper surface has grooves or protrusions, where the cross-sectional shape of the upper surface grooves or protrusions is the same as the upper surface and the area is smaller than the area of the piezoelectric film;

[0079] The lower surface is a groove or a plane and contacts the sensitive surface of the absolute pressure sensor.

[0080] Specifically, 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. Therefore, the three form a stable whole. Among them, the upper surface needs to have the same shape as the piezoelectric film and have a slightly larger area than the piezoelectric film. The two can be fixed by edge bonding. The surface of the second transmission component in contact with the piezoelectric film is designed with grooves or protrusions to increase the deformation displacement of the piezoelectric film. When a human vibration wave is conducted through 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 oscillating changes on the surface of the piezoelectric film, making it easier for the piezoelectric film to generate piezoelectric signals and making the detection of vibration signals more sensitive.

[0081] Specifically, 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 to form 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 as a groove type or a flat type. Preferably, the lower surface is designed as a groove type, and 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 with different shapes, but they need to be axisymmetric about the center 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 the piezoelectric film fixed on the upper surface of the cylinder and the 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.

[0082] Preferably, the fixing method of the second transmission component and the absolute pressure sensor is contact coupling fixation. The edge is fixed by means of Velcro bonding, snap fixation, screw fixation, or a housing that can accommodate both and has a fixed structure is put on the outside.

[0083] Further, 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.

[0084] Preferably, the upper surface of the second transmission component and the piezoelectric film are pasted by means of pasting methods such as solid glue, double-sided tape, hot melt glue, sealant, or soluble adhesive.

[0085] Preferably, 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 1The lower surface of the present embodiment is structured such that the groove just covers the absolute pressure sensor, and the bottom surface of the groove on the lower surface contacts the sensitive surface of the absolute pressure sensor.

[0086] According to the characteristics of the piezoelectric film, when there is deformation on the surface, the vibration generated by the drum surface effect enables the piezoelectric film to better generate an analog piezoelectric signal. Whether the upper surface of the second transmission component is a groove or a protrusion, as long as it can form a cavity with the piezoelectric film to receive the human vibration conducted by the first transmission component and drive the piezoelectric film at the cavity position to vibrate.

[0087] Furthermore, the shape of the second transmission component is a regular shape or a combination of regular shapes, where,

[0088] The regular shape is a cylinder, a cube, a cuboid, or a polyhedron with two parallel surfaces;

[0089] The combination of regular shapes is a stable whole formed by multiple regular shapes of the same or different types that are axis-centered symmetric, edge-aligned, and surface-contact fixed.

[0090] Furthermore, the fixing component is coupled and fixed to the second transmission component, and the sensitive surface of the absolute pressure sensor is in slight contact or non-contact with the lower surface of the second transmission component.

[0091] Preferably, the external shape of the second transmission component is a cuboid, a cylinder, or a cube, and the preferred materials are 3D printing materials such as polylactic acid (PLA), acrylonitrile-butadiene-styrene copolymer (ABS), polyethylene terephthalate glycol (PETG), thermoplastic polyurethane (TPU), or nylon.

[0092] Preferably, the absolute pressure sensor is a strain type, piezoresistive type, or capacitive type sensor, which can extract static pressure information to quantify the fitting degree between the sensor and the chest wall.

[0093] Furthermore, it includes a fixing component, the fixing component is coupled and fixed to the second transmission component, and the sensitive surface of the absolute pressure sensor is in slight contact or non-contact with the lower surface of the second transmission component.

[0094] 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.

[0095] 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.

[0096] Embodiment 2

[0097] Another embodiment of the present invention discloses a method for acquiring cardiopulmonary signals of a single sensor for detecting multi-frequency vibrations of the cardiopulmonary system. The method includes:

[0098] Using the single sensor to detect the cardiopulmonary signals of the human body to obtain an analog absolute pressure signal;

[0099] Subjecting the analog absolute pressure signal to analog-to-digital conversion and filtering processing to obtain a static pressure value reflecting the degree of fit between the human body and the sensor;

[0100] Judging whether the static pressure value is within a preset interval. If not, adjust the degree of fit between the single sensor and the human body according to the magnitude of the static pressure value, and use the single sensor to detect the cardiopulmonary signals of the human body again until the static pressure value corresponding to the obtained analog absolute pressure signal is within the preset interval;

[0101] When the static pressure value is within the preset interval, obtain the analog piezoelectric signal of the single sensor, and subject the analog piezoelectric signal to signal amplification, analog-to-digital conversion, and signal decomposition to obtain three-way synchronous ultra-low-frequency cardiac signals, cardiac shock signals, and cardiopulmonary sound signals that synchronously map the cardiac vibration frequency.

[0102] The preset interval refers to the pressure interval in which the fit state between the human body and the single sensor meets the requirements for the effectiveness of cardiopulmonary signals.

[0103] Specifically, in this embodiment, the sensor collects mechanical vibration waves generated by the human body. Among them, the piezoelectric film generates an analog piezoelectric signal based on the collected mechanical vibration waves, and the absolute pressure sensor generates an analog absolute pressure signal based on the collected mechanical vibration waves. Specifically, for the obtained continuous static pressure signal, calculate the average pressure signal as the static pressure signal value in this state:

[0104]

[0105] where P represents the static pressure signal in this state, and P i is the collected continuous static pressure signal.

[0106] 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:

[0107] N = f(P)

[0108] N is the static pressure value in this 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.

[0109] According to this pressure value, different grades of the degree of fit of the chest wall can be divided by setting thresholds.

[0110] Specifically, in this embodiment, a pressure range of 1-2N is selected as a suitable pressure interval. The fitting degree in the pressure interval less than 1N is judged as not being properly fitted, and the fitting degree in the pressure value interval greater than 2N is judged as being too tightly fitted:

[0111]

[0112] Degree represents the fitting degree between 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.

[0113] Further, the process of obtaining three-channel synchronous ultra-low-frequency cardiac signals, cardiac vibration signals, and cardio-pulmonary sound signals that synchronously map the cardiac vibration frequency by amplifying, analog-to-digital converting, and decomposing the analog piezoelectric signal includes:

[0114] Amplify the analog piezoelectric signal and convert it into a digital piezoelectric signal through analog-to-digital conversion;

[0115] Decompose the digital piezoelectric signal into a respiratory wave, ultra-low-frequency cardiac signals, cardiac vibration signals, and cardio-pulmonary sound signals;

[0116] Peak detection is performed on the respiratory wave through a peak detection function to obtain the peak of the respiratory wave; the ultra-low-frequency cardiac signals, cardiac vibration signals, and cardio-pulmonary sound signals are truncated according to the peak position of the respiratory wave to obtain multiple segments of ultra-low-frequency cardiac signals, cardiac vibration signals, and cardio-pulmonary sound signals;

[0117] For each of the segments, the peak of the ultra-low-frequency cardiac signal is extracted through a peak detection algorithm, and then the ultra-low-frequency cardiac signals, cardiac vibration signals, and cardio-pulmonary sound signals are each truncated according to the peak position to obtain multiple single-cycle ultra-low-frequency cardiac signals, cardiac vibration signals, and cardio-pulmonary sound signals with different lengths;

[0118] Select segments of single-cycle ultra-low-frequency cardiac signals, cardiac vibration signals, and cardio-pulmonary sound signals that are the same as the number of cardiac vibrations, and calculate the average period based on the periods of the above segments as the period lengths of the equal-length segments of the single-cycle ultra-low-frequency cardiac signals, cardiac vibration signals, and cardio-pulmonary sound signals;

[0119] Use the cubic spline interpolation method to process the selected segments of the unequal-length ultra-low-frequency cardiac signals, cardiac vibration signals, and cardio-pulmonary sound signals respectively to obtain corresponding equal-length single-cycle signals of the ultra-low-frequency cardiac signals, cardiac vibration signals, and cardio-pulmonary sound signals;

[0120] Perform time-domain averaging on the equal-length single-cycle signals of the ultra-low-frequency cardiac signals, cardiac vibration signals, and cardio-pulmonary sound signals to obtain single-cycle signals of the synchronous ultra-low-frequency cardiac signals, cardiac vibration signals, and cardio-pulmonary sound signals.

[0121] Specifically, for a breathing wave of a certain duration, the breathing wave peak BT is extracted through a peak-seeking function i , where i = 1, 2, 3,.......n, and n is the number of breathing waves. Since the ultra-low frequency electrocardiogram signal, ballistocardiogram signal, and cardiorespiratory sound signal are related to the cardiac cycle, therefore, the ultra-low frequency electrocardiogram signal ULF_SCG can be obtained by peak truncation i , the ballistocardiogram signal SCG i , and the cardiorespiratory sound signal PCG i fragments.

[0122] For the signals of each fragment, the peak-seeking algorithm is used to extract the peak value US-P of the cardiac vibration signal j , where j = 1, 2, 3,.......m, and m is the number of cardiac vibration waves. The ultra-low frequency cardiac vibration signal ULF_SCG is truncated according to the peak value i , the ballistocardiogram signal SCG j and the cardiorespiratory sound signal PCG j of each fragment to form multiple single-cycle fragments of different lengths. m single-cycle fragments are selected from them, and the average period of the above m single-cycle fragments is used as the period length T of the equal-length fragment:

[0123]

[0124] where T j is the period of each unequal-length fragment.

[0125] The cubic spline interpolation method is used to process the m unequal-length signals to obtain equal-length multi-cycle signals respectively:

[0126] x SCG_j = f spline (SCG j , T)

[0127] x PCG_j = f spline (PCG j , T)

[0128] x ULF_SCG_j = f spline (ULF_SCG j , T)

[0129] where x SCG_j , x PCG_j , x ULF_SCG_j are the equal-length single-cycle signal fragments of the ballistocardiogram signal, cardiorespiratory sound signal, and ultra-low frequency cardiac vibration signal respectively.

[0130] The time domain averaging is performed on the processed equal-length multi-cycle signals respectively to obtain the single-cycle signals of the synchronized ballistocardiogram signal, cardiorespiratory sound signal, and ultra-low frequency cardiac vibration signal:

[0131]

[0132]

[0133]

[0134] Among them, x SCG_ave , x PCG_ave , x ULF_SCG_ave are respectively single - cycle signals corresponding to synchronous heart vibration signals, cardio - pulmonary sound signals, and ultra - low - frequency heart vibration signals, and the period is T.

[0135] Specifically, the preset interval is based on actual human body collection using a single sensor of the present invention. Three signals from low - frequency to high - frequency, namely ULF - SCG, SCG, and PCG signals, are obtained by signal extraction of the collected piezoelectric signals. At the same time, the SCG signal based on a standard accelerometer and the PCG signal based on a microphone are collected. The following correlation analysis is performed on the SCG signals of the collected piezoelectric signals and the accelerometer, and the PCG signals of the piezoelectric and the microphone:

[0136] Select 5 - cycle continuous waveforms for pairwise correlation analysis, using the method of Pearson correlation coefficient. If the Pearson correlation coefficients all reach 95%, it is determined that the cardio - pulmonary signals are effective and meet the requirements. Take the static pressure value at this time as the benchmark, and the benchmark and above are used as the preset interval. The ULF - SCG signal does not require correlation analysis because it has no standard signal, and secondly, it is the signal least likely to be interfered with. As long as the SCG and PCG signals meet the requirements, the ULF - SCG signal will definitely meet the requirements.

[0137] In practical applications, this preset interval is a method for establishing a factory preset value before the use provided in this embodiment. Those skilled in the art should be able to understand that the method for obtaining the preset interval should not be limited to the above description, and there are other methods such as simulation, measurement, and other automated methods, or other methods for measurement.

[0138] When the static pressure value measured by the above method is not within the threshold interval range, the system does not collect and process the piezoelectric signal into multi - band cardio - pulmonary signals until the fitting degree between the sensor and the human body is adjusted to an appropriate fitting degree and the static pressure value is within the appropriate interval range. Only then will the system start to collect and process the piezoelectric signal and decompose it into multi - band cardio - pulmonary signals. The purpose of this is to first determine through the detection of the static pressure value that the sensor fits the human body properly, so as to ensure that the collected piezoelectric signal and thus the decomposed multi - band cardio - pulmonary signals are all good and available signals, reducing the energy consumption of the system for collecting and processing invalid data.

[0139] Embodiment 3

[0140] Another embodiment of the present invention discloses another method for acquiring cardiopulmonary signals using a single sensor for detecting cardiopulmonary multi-frequency vibrations, the method comprising:

[0141] Using the single sensor to detect the cardiopulmonary signals of a human body, and acquiring an analog absolute pressure signal and an analog piezoelectric signal;

[0142] Subjecting the analog absolute pressure signal to analog-to-digital conversion and filtering processing to obtain a static pressure value reflecting the degree of fit between the human body and the sensor, and subjecting the analog piezoelectric signal to signal amplification, analog-to-digital conversion and signal decomposition to obtain three synchronized ultra-low frequency cardiac signals, cardiac vibration signals and cardiopulmonary sound signals that synchronously map the cardiac vibration frequency;

[0143] Taking the three synchronized ultra-low frequency cardiac signals, cardiac vibration signals and cardiopulmonary sound signals obtained when the static pressure value is within a preset interval as effective cardiopulmonary signals.

[0144] In this embodiment, the processing algorithm of the static pressure value and the processing algorithm of the piezoelectric signal are the same as those in Embodiment 2. The difference is that in this embodiment, regardless of whether the static pressure value is within a suitable interval, the piezoelectric signal is continuously collected and processed. Preferably, the piezoelectric signal when the static pressure value is within a suitable interval is extracted or highlighted, and the multi-band cardiopulmonary signals after decomposition are processed. All signal data during the period when the patient wears the sensor will be collected and saved. Although such processing will cause an increase in system energy consumption and processing load, the retained complete data can be used for subsequent analysis and technical improvement and other purposes.

[0145] The above two embodiments provide two different options for the system application of the present invention, and those skilled in the art can select and implement according to specific scenarios and needs.

[0146] Embodiment 4

[0147] The fourth embodiment of the present invention, as Figure 2 shown, discloses a cardiopulmonary signal acquisition system using a single sensor for detecting cardiopulmonary multi-frequency vibrations. The system includes: a single sensor module for detecting cardiopulmonary multi-frequency vibrations, a signal receiving circuit module, a multi-band signal extraction module, and a signal amplification module, wherein:

[0148] The single sensor module is used to synchronously collect the piezoelectric signal and the absolute pressure signal at the cardiopulmonary thoracic position, and the structure is the same as that in Embodiment 1;

[0149] The signal receiving circuit module 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;

[0150] 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 cardio - pulmonary sound signal, and the signal filtering module is used to filter the digital absolute pressure value signal to obtain a static pressure value.

[0151] The signal processing methods in the multi - band signal extraction module and the signal receiving circuit in the system are the same as those in Embodiment 2 and will not be elaborated here.

[0152] Those skilled in the art can understand that all or part of the processes of implementing the methods in 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.

[0153] The above - mentioned 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 by the protection scope of the present invention.

Claims

1. A single sensor for detecting multi-frequency vibration of the heart and lungs, characterized in that: It includes a first transmission component, a piezoelectric film, a second transmission component, and an absolute pressure sensor which are stacked in sequence, wherein: 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.

2. A single sensor for detecting multi-frequency vibration of the heart and lungs according to claim 1, 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.

3. A single sensor for detecting multi-frequency vibration of the heart and lungs according to claim 2, 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.

4. A single sensor for detecting multi-frequency vibration of the heart and lungs according to claim 3, 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.

5. A single sensor for detecting multi-frequency vibration of the heart and lungs according to claim 4, 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.

6. A single sensor for detecting multi-frequency vibration of the heart and lungs according to claim 5, 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 and fixed.

7. A single sensor for detecting multi-frequency vibration of the heart and lungs according to claim 6, characterized in that: It comprises a fixing component, which is coupled and fixed to the second transmission component, and the sensitive surface of the absolute pressure sensor and the lower surface of the second transmission component are slightly stressed.

8. A method for acquiring cardiopulmonary signals using a single sensor for detecting cardiopulmonary multi-frequency vibrations according to any one of claims 1 to 7, characterized in that: The method comprises: Using the single sensor to detect human cardiopulmonary signals to obtain simulated absolute pressure signals; The analog absolute pressure signal is converted into digital form and filtered to obtain a static pressure value reflecting the fit between the human body and the sensor; Determine whether the static pressure value is within a preset range. If not, adjust the fit between the single sensor and the human body according to the static pressure value, and use the single sensor to detect the human cardiopulmonary signal again until the static pressure value corresponding to the obtained simulated absolute pressure signal is within the preset range. When the static pressure value is within a preset interval, an analog piezoelectric signal of the single sensor is obtained, and the analog piezoelectric signal is subjected to signal amplification, analog-to-digital conversion, and signal decomposition to obtain three-way synchronous ultra-low frequency cardiac signal, cardiac shock signal, and cardiopulmonary sound signal that synchronously map the cardiac vibration frequency; The preset interval refers to a pressure range in which the fit between the human body and the single sensor meets the requirements for the effectiveness of the cardiopulmonary signal.

9. Another single sensor cardiopulmonary signal acquisition method for detecting cardiopulmonary multi-frequency vibrations according to any one of claims 1 to 7, characterized in that: The method comprises: Using the single sensor to detect human cardiopulmonary signals to obtain simulated absolute pressure signals and simulated piezoelectric signals; The analog absolute pressure signal is subjected to analog-to-digital conversion and filtering to obtain a static pressure value reflecting the degree of fit between the human body and the sensor; the analog piezoelectric signal is subjected to signal amplification, analog-to-digital conversion and signal decomposition to obtain three-way synchronous ultra-low frequency cardiac signal, cardiac shock signal and cardiopulmonary sound signal that synchronously map the heart vibration frequency; The three-way synchronous ultra-low frequency cardiac signal, cardiac shock signal and cardiopulmonary sound signal obtained when the static pressure value is within the preset interval are used as effective cardiopulmonary signals.

10. The single sensor for detecting multi-frequency vibration of the heart and lungs according to claim 8 or 9, characterized in that: The analog piezoelectric signal is subjected to signal amplification, analog-to-digital conversion and signal decomposition to obtain three-way synchronous ultra-low frequency cardiac signal, cardiac shock signal and cardiopulmonary sound signal that synchronously map the cardiac vibration frequency, including: Amplifying the analog piezoelectric signal and converting the analog-to-digital signal into a digital piezoelectric signal; Decompose the digital piezoelectric signal into respiratory wave, ultra-low frequency cardiac signal, cardiac shock signal and cardiopulmonary sound signal; 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 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 a plurality of single-cycle ultra-low frequency cardiac signals, the cardiac tremor signal and the cardiopulmonary sound signal 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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