Muscle elasticity modulus detection system and method based on flexible wearable sensor

Abstract

The invention provides a muscle elasticity modulus detection system and method based on a flexible wearable sensor. The muscle elasticity modulus detection system comprises a flexible wearable ultrasonic sensor array, an ultrasonic pulse generation receiver and a data acquisition system / PC terminal, receiving a pulse signal generated by the ultrasonic pulse generation receiver through the flexible wearable ultrasonic sensor, converting the pulse signal into an ultrasonic signal, transmitting the ultrasonic signal to a detected object, and feeding back an ultrasonic echo signal to the ultrasonic pulse generation receiver; and the ultrasonic pulse generation receiver sends the ultrasonic echo signal to the data acquisition system / PC terminal for analysis and processing to obtain the corresponding muscle elasticity modulus. The flexible wearable ultrasonic sensor has certain flexibility, and the sensors are connected through a snakelike circuit, so that the stretchable and bending performance of the flexible wearable ultrasonic sensor array is ensured, the sensor array is more closely connected with the human body, and the wearable purpose is achieved.

Description

Technical Field

[0001] The present invention relates to the field of ultrasonic detection technology, and in particular to a muscle elastic modulus detection system and method based on a flexible wearable sensor, and more particularly to a muscle state and elastic modulus detection system based on a flexible micro wearable ultrasonic sensor. Background Art

[0002] Detecting physiological signals of humans or animals is a key part of medicine and scientific research. It not only helps in early diagnosis of diseases and evaluation of treatment effects, but also provides health management and biofeedback training for individuals. In addition, physiological signal detection also plays an important role in virtual reality, augmented reality and fitness, providing users with a more realistic experience and optimized exercise plans. Detecting and analyzing physiological signals of organisms can help scientists and researchers gain a deeper understanding of the body's functions and mechanisms, and promote the research and development of medicine and biological sciences.

[0003] Ultrasound detection is a non-invasive, real-time and dynamic observation method that can provide detailed information about the internal tissues and organs of the human body. Compared with other technologies, ultrasound has the advantages of low cost, no radiation risk and high resolution, and can also provide information about blood flow and tissue hardness through multiple modes. Therefore, ultrasound is regarded as an efficient and versatile tool in the medical field. In recent years, methods of using ultrasound to detect muscle movement status information have been reported in many literatures. At present, the main methods of using ultrasound to detect muscle movement status information are A-ultrasound and B-ultrasound. At present, the main methods of using ultrasound to detect muscle elastic modulus are MRI, quasi-static elastic imaging and dynamic elastic imaging.

[0004] In the field of ultrasonic testing: On the one hand, for the problem of muscle movement state information, A-ultrasound uses independent ultrasonic sensors to scan different depths of a certain position to obtain one-dimensional characteristics; while B-ultrasound is generally an array ultrasonic sensor, which scans a certain section to obtain two-dimensional characteristics; due to the large size and high cost of B-ultrasound equipment, it is not suitable to be used as a wearable sensor device. On the other hand, for the problem of muscle elastic modulus, MRI is expensive to use and has slow imaging speed; dynamic elastic imaging requires access to an external vibration source or acoustic radiation excitation, so they are not suitable to be used as wearable sensing devices. This application adopts A-ultrasound and quasi-static elastic imaging principles to detect muscle state and elastic modulus respectively. This application mainly uses the quasi-static elastic imaging principle to detect muscle elastic modulus. Based on different ultrasonic detection steps and ultrasonic signal processing methods, this system can also use the A-ultrasound principle to detect muscle movement state information.

[0005] Flexible wearable sensors are a rapidly developing technology field in recent years. They combine advanced research in microelectronics, nanotechnology and biomedical engineering to bring innovative solutions to various application fields. Compared with traditional rigid sensors, flexible wearable sensors can fit closely to the skin or clothing. Due to its flexibility, it can better adapt to various curves and movements of the body, so as to better capture and respond to external stimuli. Based on factors such as micro-sensing manufacturing process, device integration, and use environment, previous flexible wearable sensors have many limitations during use. On the one hand, the durability of the sensor material itself is limited during use. During repeated bending, stretching or long-term wearing, the material may fatigue or be damaged, resulting in sensor performance degradation or failure. On the other hand, the traditional structural design and material selection may cause the sensor to not fit the skin completely, especially in parts of the body that bend or move frequently, which may cause the sensor to fall off, become unstable, or cause skin discomfort and allergic reactions, limiting its possibility of long-term wear. In addition, the ultrasound field has high requirements for signals in the sensing detection process. The sensitivity and accuracy of previous flexible wearable sensors in data acquisition are insufficient, affecting their effectiveness and reliability in practical applications.

[0006] Therefore, technicians in this field are committed to developing a flexible wearable ultrasound system for detecting muscle status and elastic modulus. Summary of the invention

[0007] In view of the defects in the prior art, the object of the present invention is to provide a muscle elastic modulus detection system and method based on a flexible wearable sensor.

[0008] A muscle elastic modulus detection system based on a flexible wearable sensor provided by the present invention comprises: a flexible wearable ultrasonic sensor array, an ultrasonic pulse generator receiver and a data acquisition system / PC terminal;

[0009] The flexible wearable ultrasonic sensor receives the pulse signal generated by the ultrasonic pulse generator receiver, converts the pulse signal into an ultrasonic signal and transmits it to the detected object, and feeds back the ultrasonic echo signal to the ultrasonic pulse generator receiver; the ultrasonic pulse generator receiver sends the ultrasonic echo signal to the data acquisition system / PC for analysis and processing to obtain the corresponding muscle elastic modulus.

[0010] Preferably, the flexible wearable ultrasound sensor array comprises a plurality of flexible wearable ultrasound sensors;

[0011] The spatial arrangement of the flexible wearable ultrasonic sensor includes a linear array, an arc array, and a dot array;

[0012] There is a spacing between adjacent and opposite flexible wearable ultrasonic sensors to reduce crosstalk between signals, and the spacing should be greater than or equal to half the wavelength of ultrasonic waves.

[0013] Preferably, the flexible wearable ultrasonic sensors are connected by a serpentine circuit;

[0014] The structure of the flexible wearable ultrasonic sensor adopts a double-layer symmetrical structure, which is fixed to each other by an adhesive layer.

[0015] Preferably, the flexible wearable ultrasonic sensor comprises a protective layer, an electromagnetic shielding layer, a sound insulation material, an electrode layer, a piezoelectric material film and an adhesion layer;

[0016] The protective layer and the electromagnetic shielding layer are symmetrically distributed in the upper and lower regions, and as the outermost layer of the flexible wearable ultrasonic sensor, the sound insulation material is not bonded to the electromagnetic shielding layer and the electrode layer, so as to eliminate the back reflection of ultrasonic waves; the electrode layer includes an upper electrode layer, a middle electrode layer and a lower electrode layer;

[0017] The upper and lower electrode layers are connected to the ground terminal, and the middle electrode layer is bonded to the piezoelectric material film and connected to the active voltage terminal.

[0018] Preferably, the protective layer is composed of a polyimide film for structural protection and electrical insulation;

[0019] The electromagnetic shielding layer is composed of a flexible brass film and is used for electromagnetic shielding to reduce environmental noise;

[0020] The electrode layer is composed of conductive silver ink;

[0021] The piezoelectric material film is composed of 1 to 2 layers of flexible piezoelectric material and is used to generate and receive ultrasonic signals.

[0022] Preferably, the ultrasonic pulse generator receiver comprises an ultrasonic pulse transmitting circuit, an ultrasonic echo receiving circuit and a pulse generating and receiving conversion circuit;

[0023] The ultrasonic pulse transmitting circuit includes a controller and a pulse generator, which are used to generate a required waveform and generate an ultrasonic pulse signal based on the waveform, and perform phase control on the ultrasonic pulse signal of each channel as required;

[0024] The ultrasonic echo receiving circuit includes a signal amplifier and filter, an analog-to-digital converter and an input-output buffer, which are used to amplify and filter the ultrasonic echo signal and convert the analog signal into a digital signal;

[0025] The pulse generation and reception conversion circuit is used to realize the conversion between the transmitting and receiving circuits.

[0026] According to a muscle elastic modulus detection method based on a flexible wearable sensor provided by the present invention, using the muscle elastic modulus detection system based on a flexible wearable sensor, the detection method includes:

[0027] Step S1: Wearing the flexible wearable ultrasonic sensor array on the surface of the body in the detected area, and receiving the pulse signal sent by the ultrasonic pulse generator and receiver;

[0028] Step S2: Each flexible wearable ultrasonic sensor in the flexible wearable ultrasonic sensor array converts the pulse signal into an ultrasonic signal in turn, and transmits the ultrasonic signal to the measured area;

[0029] Step S3: each sensor in the flexible wearable ultrasonic sensor array receives an ultrasonic echo signal, and feeds back the ultrasonic echo signal to the ultrasonic pulse generator receiver according to each channel;

[0030] Step S4: after applying strain to the measured area, executing steps S1 to S3 again, and then executing step S5;

[0031] Step S5: The ultrasonic pulse generator receiver receives two ultrasonic echo signals, performs analog-to-digital conversion, and then sends them to the data acquisition system / PC end. The data acquisition system / PC end performs cross-correlation analysis on the two ultrasonic echo signals to detect the distribution of muscle elastic modulus.

[0032] Preferably, step S5 comprises:

[0033] Step S5.1: After obtaining the ultrasonic echo signals before and after applying the micro strain through the data acquisition system / PC, the ultrasonic echo signals are respectively subjected to signal filtering and denoising processing, and corresponding features are extracted;

[0034] Step S5.2: Based on the time domain cross-correlation algorithm, a sliding window is used within a reasonable time domain range to analyze and process the mutual correlation of the ultrasonic echo signals before and after the application of the micro-strain, and the time delay corresponding to the characteristic windows of the two ultrasonic echo signals is found;

[0035] Step S5.3: calculating the displacement of the detected object under axial static pressure according to the time delay, and calculating the strain of the detected tissue by difference;

[0036] Step S5.4: using an elasticity theory model to relate the measured strain to the external force, and calculating the elastic modulus of the detected object based on the elasticity theory model and the ultrasonic signal data.

[0037] Preferably, the characteristics include maximum and minimum amplitudes, signal frequency content, and signal duration;

[0038] The elasticity theory model includes Hawke's law.

[0039] Preferably, the method further comprises detecting the muscle movement state, and the detection method comprises the following steps:

[0040] Step A: Wear the flexible wearable ultrasonic sensor array on the surface of the body in the detected area, the ultrasonic pulse generator receiver sends a pulse signal to the flexible wearable ultrasonic sensor array, and each sensor in the flexible wearable ultrasonic sensor array converts the pulse signal into an ultrasonic signal in turn, and transmits the ultrasonic signal to the detected area;

[0041] Step B: Each sensor in the flexible wearable ultrasonic sensor array receives an ultrasonic echo signal and feeds the ultrasonic echo signal back to the ultrasonic pulse generator receiver according to each channel.

[0042] Step C: The ultrasonic pulse generator receiver performs analog-to-digital conversion on the ultrasonic echo signal and sends it to the data acquisition system / PC end, and the data acquisition system / PC end analyzes the ultrasonic echo signal to detect the muscle movement state;

[0043] The step C includes performing signal filtering and denoising processing on the ultrasonic echo signal acquired during the continuous detection process based on the pulse-echo method, extracting the time characteristics and frequency characteristics, and identifying different muscle movement states by comparing the ultrasonic echo signals at consecutive time points in the time domain and frequency.

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

[0045] 1. The flexible wearable ultrasonic sensor structure constructed by the present invention adopts a multi-layer design. Through the encapsulation of the protective layer, the durability during use is improved while ensuring the sensing performance. It has multiple working modes, so that the flexible wearable ultrasonic detection system can meet different working requirements, and the multi-channel sensors can work independently without interfering with each other, so as to achieve good working performance requirements.

[0046] 2. The present invention ensures the stretchability and bendability of the flexible wearable ultrasonic sensor array by miniaturizing the flexible wearable ultrasonic sensor and using a serpentine circuit for electrode connection, so that the sensor array is more closely connected to the human body and remains stable during repeated bending, stretching or long-term wearing.

[0047] 3. The present invention ensures good piezoelectric performance and anti-noise interference ability of the sensor through the electromagnetic shielding layer and the multi-layer piezoelectric material structure design, and achieves focusing effect through phase control of the ultrasonic signal of the flexible wearable ultrasonic sensor array, thereby ensuring the sensitivity and accuracy of the ultrasonic signal data to the greatest extent.

[0048] 4. The present invention performs phase control on the ultrasonic signal output to the flexible wearable ultrasonic sensor connected to each channel according to actual needs, thereby effectively enhancing the strength of the ultrasonic signal.

[0049] 5. The ultrasonic pulse generator receiver of the present invention can realize logic control capability and perform phase control on the ultrasonic signal output to the flexible wearable ultrasonic sensor connected to each channel according to actual needs, so as to achieve the effect of focusing the ultrasonic signal, thereby effectively enhancing the ultrasonic signal strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0051] Figure 1 It is a structural schematic diagram of the ultrasonic detection system of the present invention;

[0052] Figure 2 A schematic diagram of a double-layer structure of a specific embodiment of a flexible wearable ultrasonic sensor in an ultrasonic detection system of the present invention;

[0053] Figure 3 It is a structural schematic diagram of a specific embodiment of an ultrasonic pulse generator receiver in an ultrasonic detection system of the present invention;

[0054] Figure 4 It is a schematic diagram of the elastic modulus detection principle based on the flexible micro wearable ultrasonic sensor in the present invention;

[0055] Figure 5 It is a schematic diagram of a detection method of an embodiment of the ultrasonic detection system of the present invention. DETAILED DESCRIPTION

[0056] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0057] The present invention is based on measuring the relationship between the strain (displacement) and external force of muscle tissue under the action of a small external force, thereby estimating the elastic properties of the tissue. An axial static pressure perpendicular to the contact surface is applied to the surface of the object to be detected, causing a controllable displacement of the tissue to be detected below. Under the control of an ultrasonic pulse generator receiver, a flexible micro-wearable ultrasonic sensor array is used to receive the internal ultrasonic signal of the tissue to be detected before and after the axial static pressure is applied, and the signal data is collected, stored and processed by a data acquisition system / PC. By analyzing and processing the mutual correlation of the ultrasonic echo signals, the displacement of the object to be detected under the axial static pressure is calculated, and the strain of the tissue to be detected is calculated by difference. The measured strain is linked to the external force using an elastic theory model, and the elastic modulus of the object to be detected is calculated based on the model and the ultrasonic signal data.

[0058] Embodiment 1

[0059] According to a muscle elastic modulus detection system based on a flexible wearable sensor provided by the present invention, Figure 1 As shown, it includes: a flexible wearable ultrasonic sensor array, an ultrasonic pulse generator receiver and a data acquisition system / PC terminal; the flexible wearable ultrasonic sensor receives the pulse signal generated by the ultrasonic pulse generator receiver, converts the pulse signal into an ultrasonic signal and transmits it to the detected object, and feeds back the ultrasonic echo signal to the ultrasonic pulse generator receiver; the ultrasonic pulse generator receiver sends the ultrasonic echo signal to the data acquisition system / PC terminal for analysis and processing to obtain the corresponding muscle elastic modulus. At the same time, the muscle elastic modulus detection system based on the flexible wearable sensor can also use the A-ultrasound principle to detect muscle movement state information, that is, this system is also suitable for A-type ultrasound and quasi-static elastic imaging.

[0060] Specifically, Figure 1 As shown, each flexible wearable ultrasonic sensor (14) receives a pulse signal from an ultrasonic pulse generator receiver (12) and sends an ultrasonic signal to the area to be tested. After acquiring an ultrasonic echo signal from the body of the tested area, the flexible wearable ultrasonic sensor feeds back the ultrasonic echo signal to the ultrasonic pulse generator receiver (12). The ultrasonic pulse generator receiver (12) performs analog-to-digital conversion on the ultrasonic echo signal and sends it to the data acquisition system / PC end (13).

[0061] The flexible wearable ultrasonic sensor array includes a plurality of flexible wearable ultrasonic sensors 14, and the arrangement includes an arrangement of m×n flexible wearable ultrasonic sensors. The flexible wearable ultrasonic sensors are connected with a serpentine circuit, which ensures the stretchability and bending performance of the flexible wearable ultrasonic sensor array, so that the sensor array is more closely connected to the human body. The flexible wearable ultrasonic sensor includes a protective layer (141), an electromagnetic shielding layer (142), a sound insulation material (143), an electrode layer (144), a piezoelectric material film (145) and an adhesion layer (146). Figure 2 As shown, the structure of the flexible wearable ultrasonic sensor adopts a double-layer symmetrical structure, which is fixed to each other by an adhesive layer (146) to achieve an acoustic series effect. The protective layer and the electromagnetic shielding layer are symmetrically distributed in the upper and lower regions, serving as the outermost layer of the flexible wearable ultrasonic sensor. The protective layer is composed of a polyimide film for structural protection and electrical insulation; the electromagnetic shielding layer is composed of a flexible brass film for electromagnetic shielding to reduce environmental noise. The sound insulation material is not bonded to the electromagnetic shielding layer and the electrode layer, and is used to eliminate the back reflection of ultrasonic waves. The electrode layer is composed of conductive silver ink, wherein the upper and lower electrode layers are connected to the ground terminal, and the middle electrode layer is bonded to the piezoelectric material film and connected to the active voltage terminal. The piezoelectric material film is composed of 1 to 2 layers of flexible piezoelectric material, which is used to generate and receive ultrasonic signals. The flexible piezoelectric material is acoustically connected in series to ensure the required ultrasonic signal strength.

[0062] In addition, after receiving the pulse signal from the ultrasonic pulse generator receiver, the piezoelectric material film generates high-frequency vibration and emits an ultrasonic signal due to the inverse piezoelectric effect of the piezoelectric material. There is a certain distance between adjacent and relative flexible wearable ultrasonic sensors to reduce crosstalk between signals. Normally, the distance should be greater than or equal to half the wavelength of the ultrasonic wave. The flexible wearable ultrasonic sensor array can specify the ultrasonic sensor channels for each emission and reception of ultrasonic signals, and is not limited to the pulse-echo detection method in actual use.

[0063] It should be noted that Figure 1 , Figure 2 The number of sensors and spatial arrangement shown in the are not limitations of the technical solution. In actual applications, the number of ultrasonic sensors used can be determined according to needs to adapt to different application scenarios and body parts, thereby optimizing the ultrasonic detection effect and improving user comfort and sensor durability. According to the part to be detected, the flexible wearable ultrasonic sensor can be spatially arranged in a linear array (such as biceps and triceps), an arc array (such as the upper arm, thigh and quadriceps), a dot array (such as the rectus abdominis and oblique abdominal muscles), etc. The flexible wearable ultrasonic sensor array can be worn on the surface of the body in the detected area at multiple angles and in all directions according to needs.

[0064] The ultrasonic pulse generator receiver is used to sequentially send pulse signals to the flexible wearable ultrasonic sensors connected to each channel, and sequentially receive ultrasonic echo signals fed back by each flexible wearable ultrasonic sensor, so as to detect the dynamic changes and elastic modulus of the muscles inside the body. Figure 3 As shown, the ultrasonic pulse generator receiver includes an ultrasonic pulse transmitting circuit 121, an ultrasonic echo receiving circuit 122 and a pulse generating receiving conversion circuit 123. The ultrasonic pulse transmitting circuit includes a controller 1211 and a pulse generator 1212, which are used to generate the required waveform and generate an ultrasonic pulse signal based on the waveform, and perform phase control on the ultrasonic pulse signal of each channel as required. The ultrasonic echo receiving circuit includes a signal amplifier and filter 1221, an analog-to-digital converter 1222 and an input-output buffer 1223, which are used to amplify and filter the ultrasonic echo signal and convert the analog signal into a digital signal. It should be noted that in a specific embodiment, the pulse signal emitted by the ultrasonic pulse generator receiver is applied to all sensors to improve processing efficiency. The pulse generating receiving conversion circuit is used to realize the conversion of the transmitting and receiving circuits. The ultrasonic pulse generator receiver can realize the logic control capability, and according to actual needs, the ultrasonic signal output to the flexible wearable ultrasonic sensor connected to each channel is phase controlled to achieve the effect of focusing the ultrasonic signal, thereby effectively enhancing the strength of the ultrasonic signal.

[0065] The data acquisition system / PC end is used to collect, store and process signal data to analyze specific dynamic changes. The data acquisition system / PC end uses a multi-channel anti-sound system to collect, store and process the ultrasonic echo signals fed back by the flexible wearable ultrasonic sensors of each channel, analyzes the state and elastic modulus of the measured muscle tissue based on the ultrasonic echo signal, and generates parameter results such as tissue state judgment and elastic modulus distribution diagram. In practical applications, such as detecting the state of muscle movement, it is only necessary to process and analyze the ultrasonic echo signal once to detect the dynamic changes of the muscles inside the body; such as detecting the elastic modulus of the muscle, it is necessary to analyze and process the initial ultrasonic echo signal and the correlation between the ultrasonic echo signal after applying a small strain to detect the distribution of the elastic modulus inside the body.

[0066] Embodiment 2

[0067] According to a muscle elastic modulus detection method based on a flexible wearable sensor provided by the present invention, a muscle elastic modulus detection system based on a flexible wearable sensor is used, such as Figure 4 As shown, the detection method includes:

[0068] Step S1: Wear the flexible wearable ultrasonic sensor array on the surface of the body in the detected area, and receive the pulse signal sent by the ultrasonic pulse generator and receiver.

[0069] Step S2: Each flexible wearable ultrasonic sensor in the flexible wearable ultrasonic sensor array will convert the pulse signal into an ultrasonic signal in turn, and transmit the ultrasonic signal to the measured area.

[0070] Step S3: Each sensor in the flexible wearable ultrasonic sensor array receives an ultrasonic echo signal, and feeds back the ultrasonic echo signal to the ultrasonic pulse generator receiver according to each channel.

[0071] Step S4: after applying strain to the measured area, execute steps S1 to S3 again and then execute step S5.

[0072] Step S5: The ultrasonic pulse generator receiver receives two ultrasonic echo signals, performs analog-to-digital conversion, and then sends them to the data acquisition system / PC end, and the data acquisition system / PC end performs cross-correlation analysis on the two ultrasonic echo signals to detect the muscle elastic modulus distribution. Step S5 includes:

[0073] Step S5.1: After obtaining the ultrasonic echo signals before and after applying the micro-strain through the data acquisition system / PC, the ultrasonic echo signals are respectively subjected to signal filtering and denoising, and corresponding features are extracted, including the maximum and minimum amplitudes, signal frequency components, signal duration, etc.

[0074] Step S5.2: Based on the time domain cross-correlation algorithm, a sliding window is used within a reasonable time domain range to analyze and process the correlation between the ultrasonic echo signals before and after the application of the micro-strain, and to find the time delay corresponding to the characteristic windows of the two ultrasonic echo signals.

[0075] Step S5.3: Calculate the displacement of the detected object under axial static pressure according to the time delay, and calculate the strain of the detected tissue by difference.

[0076] Step S5.4: Use the elasticity theory model to relate the measured strain to the external force, and calculate the elastic modulus of the object to be tested based on the elasticity theory model and the ultrasonic signal data. The elasticity theory model includes Hawke's law, and the formula is as follows:

[0077]

[0078] Where x(t) and X′(t) are the signals before and after applying a small strain, respectively, T is the size of the sliding window, and τ represents the time shift between two corresponding sliding windows. xx′The larger (τ) is, the more similar the two sliding windows are. When it reaches the maximum value, it indicates that the signal before applying a small strain is most consistent with the signal after the application when the time shift is τ(t). Therefore, it is considered that the time shift of this window is τ(t).

[0079] Ideally, the ultrasonic velocity is constant at c, and the displacement u(t) of the object being tested at the position of the sliding window can be calculated by the following formula. By traversing all sliding windows, the overall displacement of the tissue being tested can be obtained.

[0080]

[0081] The displacement map of the measured tissue is subjected to gradient calculation (differential) to obtain the elastic distribution of the tissue. Assuming that X and X' represent the position of the same tissue window after compression and before compression, respectively, and Y and Y' represent the position of another window of the same tissue after compression and before compression, respectively, the average strain of the tissue between X and Y is:

[0082]

[0083] Among them, Δt 1 represents the distance between X and Y, Δt 2 Indicates the distance between X' and Y'.

[0084] Δt 1 =XY (4)

[0085] Δt 2 =X′-Y′=(X+d 1 )-(Y+d 2 ) (5)

[0086] Among them, d 1 is the displacement from X to X', d 2 is the displacement from Y to Y', that is, the displacement obtained by the displacement estimation algorithm.

[0087]

[0088] So the strain δ between X and Y XY It can be obtained through differential operation of displacement. Finally, the elastic modulus distribution of the object under test is characterized based on the elastic theory model through the strain distribution of the tissue.

[0089] The structural design of the flexible wearable ultrasonic sensor avoids the influence of electromagnetic interference and electrodes during the acquisition process. It has multiple working modes, including pulse-echo mode and pulse-penetration mode. Pulse-echo mode: In this mode, the flexible wearable ultrasonic sensor transmits high-frequency ultrasonic pulses into the muscle tissue, and receives the echo signal reflected from the object to be measured through the original sensor to obtain the characteristic information of the target. Pulse-penetration mode: Different from the pulse-echo mode. In the pulse-penetration mode, the flexible wearable ultrasonic sensor transmits high-frequency ultrasonic pulses into the muscle tissue, passes through the object to be measured, and is detected by different flexible wearable ultrasonic sensors on the other side. This allows the flexible wearable ultrasonic detection system to meet different working requirements. Multi-channel sensors can work independently without interfering with each other to achieve good working performance requirements.

[0090] Furthermore, combined with Figures 4 to 5 The muscle elastic modulus detection method based on the flexible wearable sensor of the present invention is specifically described as follows:

[0091] The ultrasonic pulse generator and receiver sequentially transmits pulse signals to the flexible wearable ultrasonic sensors connected to each ultrasonic channel. Each flexible wearable ultrasonic sensor transmits an ultrasonic signal to the inside of the body of the measured area and receives an ultrasonic echo signal. The ultrasonic pulse generator and receiver sequentially receives the ultrasonic echo signal fed back by the flexible wearable ultrasonic sensor connected to each ultrasonic channel through each ultrasonic channel. The ultrasonic pulse generator and receiver performs analog-to-digital conversion on the ultrasonic echo signal and sends it to the data acquisition system / PC. For example, to detect the state of muscle movement, it is only necessary to process and analyze the ultrasonic echo signal once to detect the dynamic changes of the muscles inside the body. Figure 4 As shown, if the elastic modulus of the object to be tested needs to be detected, a pressure device is required to apply an axial static pressure perpendicular to the contact surface on the surface of the object to be tested (such as by pressing or gently pushing), so that the tissue to be tested below undergoes a controllable displacement. Since the application of the axial static pressure is controlled to ensure that the displacement is within a safe range and can be accurately measured. Based on the control of the ultrasonic pulse generator receiver (12), a flexible micro wearable ultrasonic sensor array (11) is used to receive the internal ultrasonic signal of the tissue to be tested before and after the axial static pressure is applied, and the signal data is collected, stored and processed by the data acquisition system / PC end (13). By analyzing and processing the mutual correlation of the ultrasonic echo signals, the displacement of the object to be tested under the axial static pressure is calculated, and the strain of the tissue to be tested is calculated by difference. The measured strain is linked to the external force using an elasticity theory model (such as Hawke's law), and the elastic modulus of the object to be tested is calculated based on the model and the ultrasonic signal data.

[0092] like Figure 5The figure shows a schematic diagram of a detection method of a muscle state and elastic modulus detection system based on a flexible wearable ultrasonic sensor, which omits the ultrasonic pulse generator receiver (12) and the data acquisition system / PC terminal (13). The arrangement method detects the muscle state and elastic modulus of the upper arm of the human body based on an array of flexible wearable ultrasonic sensors. In actual practice, the number and arrangement of the flexible wearable ultrasonic sensor array can be adjusted as needed.

[0093] Embodiment 3

[0094] By using the muscle elastic modulus detection system based on the flexible wearable sensor, the present invention can also detect the muscle movement state, and the detection method includes the following steps:

[0095] Step A: The flexible wearable ultrasonic sensor array is worn on the body surface of the detected area at multiple angles and in all directions as needed, the ultrasonic pulse generator receiver sends a pulse signal to the flexible wearable ultrasonic sensor array, and each sensor in the flexible wearable ultrasonic sensor array converts the pulse signal into an ultrasonic signal in turn, and transmits the ultrasonic signal to the detected area.

[0096] Step B: Each sensor in the flexible wearable ultrasonic sensor array receives an ultrasonic echo signal and feeds the ultrasonic echo signal back to the ultrasonic pulse generator receiver according to each channel.

[0097] Step C: The ultrasonic pulse generator receiver performs analog-to-digital conversion on the ultrasonic echo signal and sends it to the data acquisition system / PC, which analyzes the ultrasonic echo signal to detect the muscle movement state. Step C includes filtering and denoising the ultrasonic echo signal acquired during the continuous detection process based on the pulse-echo method, extracting the time characteristics and frequency characteristics, and identifying different muscle movement states by comparing the ultrasonic echo signals at consecutive time points in the time domain and frequency. Specifically, based on the pulse-echo method, since the ultrasonic signal will be reflected when it encounters tissues of different densities (such as muscle, fat, and bone) when penetrating the skin and tissues. During the continuous detection process, the acquired ultrasonic echo signal represents the reflection intensity and time difference of different tissue layers inside the muscle, and these data can be used to analyze the shape, thickness, and movement state of the muscle. After filtering and denoising the ultrasonic echo signal, typical time features (such as amplitude and arrival time) and frequency features can be extracted. By comparing the ultrasonic echo signals at consecutive time points in the time domain and frequency, different muscle movement states can be identified, such as static contraction, dynamic contraction, isometric contraction, etc.

[0098] According to actual needs, the ultrasonic signal output to the flexible wearable ultrasonic sensor connected to each channel is phase controlled, and the phase control is achieved by accurately adjusting the time difference (phase) of each flexible wearable ultrasonic sensor unit transmitting or receiving the ultrasonic signal. By adjusting the phase, the ultrasonic signal can be coherently superimposed in a specific direction and depth to form a focal point or a directional beam. Phase control can help overcome signal distortion and noise problems, improve the resolution and accuracy of ultrasonic signals, and ensure high-quality signal acquisition. Thereby effectively enhancing the strength of ultrasonic signals.

[0099] Those skilled in the art know that, in addition to realizing the system and its various devices, modules, and units provided by the present invention in a purely computer-readable program code, it is entirely possible to realize the same functions in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, the system and its various devices, modules, and units provided by the present invention can be considered as a hardware component, and the devices, modules, and units included therein for realizing various functions can also be regarded as structures within the hardware component; the devices, modules, and units for realizing various functions can also be regarded as both software modules for realizing the method and structures within the hardware component.

[0100] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A muscle elastic modulus detection system based on a flexible wearable sensor, characterized in that: include: Flexible wearable ultrasound sensor array, ultrasound pulse generator receiver and data acquisition system / PC terminal; The flexible wearable ultrasonic sensor receives the pulse signal generated by the ultrasonic pulse generator receiver, converts the pulse signal into an ultrasonic signal and transmits it to the detected object, and feeds back the ultrasonic echo signal to the ultrasonic pulse generator receiver; the ultrasonic pulse generator receiver sends the ultrasonic echo signal to the data acquisition system / PC for analysis and processing to obtain the corresponding muscle elastic modulus.

2. The muscle elastic modulus detection system based on flexible wearable sensor according to claim 1, characterized in that: The flexible wearable ultrasonic sensor array comprises a plurality of flexible wearable ultrasonic sensors; The spatial arrangement of the flexible wearable ultrasonic sensor includes a linear array, an arc array, and a dot array; There is a spacing between adjacent and opposite flexible wearable ultrasonic sensors to reduce crosstalk between signals, and the spacing should be greater than or equal to half the wavelength of ultrasonic waves.

3. The muscle elastic modulus detection system based on flexible wearable sensor according to claim 2 is characterized in that: The flexible wearable ultrasonic sensors are connected with a serpentine circuit; The structure of the flexible wearable ultrasonic sensor adopts a double-layer symmetrical structure, which is fixed to each other by an adhesive layer.

4. The muscle elastic modulus detection system based on flexible wearable sensor according to claim 2, characterized in that: The flexible wearable ultrasonic sensor comprises a protective layer, an electromagnetic shielding layer, a sound insulation material, an electrode layer, a piezoelectric material film and an adhesion layer; The protective layer and the electromagnetic shielding layer are symmetrically distributed in the upper and lower regions, and as the outermost layer of the flexible wearable ultrasonic sensor, the sound insulation material is not bonded to the electromagnetic shielding layer and the electrode layer, so as to eliminate the back reflection of ultrasonic waves; the electrode layer includes an upper electrode layer, a middle electrode layer and a lower electrode layer; The upper and lower electrode layers are connected to the ground terminal, and the middle electrode layer is bonded to the piezoelectric material film and connected to the active voltage terminal.

5. The muscle elastic modulus detection system based on flexible wearable sensor according to claim 4 is characterized in that: The protective layer is composed of a polyimide film and is used for structural protection and electrical insulation; The electromagnetic shielding layer is composed of a flexible brass film and is used for electromagnetic shielding to reduce environmental noise; The electrode layer is composed of conductive silver ink; The piezoelectric material film is composed of 1 to 2 layers of flexible piezoelectric material and is used to generate and receive ultrasonic signals.

6. The muscle elastic modulus detection system based on flexible wearable sensor according to claim 1, characterized in that: The ultrasonic pulse generating receiver comprises an ultrasonic pulse transmitting circuit, an ultrasonic echo receiving circuit and a pulse generating and receiving conversion circuit; The ultrasonic pulse transmitting circuit includes a controller and a pulse generator, which are used to generate a required waveform and generate an ultrasonic pulse signal based on the waveform, and perform phase control on the ultrasonic pulse signal of each channel as required; The ultrasonic echo receiving circuit includes a signal amplifier and filter, an analog-to-digital converter and an input-output buffer, which are used to amplify and filter the ultrasonic echo signal and convert the analog signal into a digital signal; The pulse generation and reception conversion circuit is used to realize the conversion between the transmitting and receiving circuits.

7. A method for detecting muscle elastic modulus based on a flexible wearable sensor, characterized in that: The muscle elastic modulus detection system based on the flexible wearable sensor according to any one of claims 1 to 6 is adopted, and the detection method comprises: Step S1: Wearing the flexible wearable ultrasonic sensor array on the surface of the body in the detected area, and receiving the pulse signal sent by the ultrasonic pulse generator and receiver; Step S2: Each flexible wearable ultrasonic sensor in the flexible wearable ultrasonic sensor array converts the pulse signal into an ultrasonic signal in turn, and transmits the ultrasonic signal to the measured area; Step S3: each sensor in the flexible wearable ultrasonic sensor array receives an ultrasonic echo signal, and feeds back the ultrasonic echo signal to the ultrasonic pulse generator receiver according to each channel; Step S4: after applying strain to the measured area, executing steps S1 to S3 again, and then executing step S5; Step S5: The ultrasonic pulse generator receiver receives two ultrasonic echo signals, performs analog-to-digital conversion, and then sends them to the data acquisition system / PC end. The data acquisition system / PC end performs cross-correlation analysis on the two ultrasonic echo signals to detect the distribution of muscle elastic modulus.

8. The muscle elastic modulus detection method based on a flexible wearable sensor according to claim 7, characterized in that: The step S5 comprises: Step S5.1: After obtaining the ultrasonic echo signals before and after applying the micro strain through the data acquisition system / PC, the ultrasonic echo signals are respectively subjected to signal filtering and denoising processing, and corresponding features are extracted; Step S5.2: Based on the time domain cross-correlation algorithm, a sliding window is used within a reasonable time domain range to analyze and process the mutual correlation of the ultrasonic echo signals before and after the application of the micro-strain, and the time delay corresponding to the characteristic windows of the two ultrasonic echo signals is found; Step S5.3: calculating the displacement of the detected object under axial static pressure according to the time delay, and calculating the strain of the detected tissue by difference; Step S5.4: using an elasticity theory model to relate the measured strain to the external force, and calculating the elastic modulus of the detected object based on the elasticity theory model and the ultrasonic signal data.

9. The muscle elastic modulus detection method based on a flexible wearable sensor according to claim 8, characterized in that: The characteristics include maximum and minimum amplitudes, signal frequency content, and signal duration; The elasticity theory model includes Hawke's law.

10. The muscle elastic modulus detection method based on a flexible wearable sensor according to claim 7, characterized in that: The method also includes detecting the muscle movement state, and the detection method includes the following steps: Step A: Wear the flexible wearable ultrasonic sensor array on the surface of the body in the detected area, the ultrasonic pulse generator receiver sends a pulse signal to the flexible wearable ultrasonic sensor array, and each sensor in the flexible wearable ultrasonic sensor array converts the pulse signal into an ultrasonic signal in turn, and transmits the ultrasonic signal to the detected area; Step B: Each sensor in the flexible wearable ultrasonic sensor array receives an ultrasonic echo signal and feeds the ultrasonic echo signal back to the ultrasonic pulse generator receiver according to each channel. Step C: The ultrasonic pulse generator receiver performs analog-to-digital conversion on the ultrasonic echo signal and sends it to the data acquisition system / PC end, and the data acquisition system / PC end analyzes the ultrasonic echo signal to detect the muscle movement state; The step C includes performing signal filtering and denoising processing on the ultrasonic echo signal acquired during the continuous detection process based on the pulse-echo method, extracting the time characteristics and frequency characteristics, and identifying different muscle movement states by comparing the ultrasonic echo signals at consecutive time points in the time domain and frequency.

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