High-precision portable multi-channel bioelectricity acquisition system based on dry electrode

Abstract

The utility model discloses a high-precision portable multi-channel bioelectricity acquisition system based on a dry electrode. The bioelectricity acquisition system comprises a plurality of integrated dry electrodes which are respectively arranged at a plurality of to-be-acquired parts of a human body; each integrated dry electrode comprises an acquisition dry electrode and a follower circuit, the acquisition dry electrode is used for acquiring a bio-electricity signal, and a data input end of the follower circuit is connected with a data output end of the corresponding acquisition dry electrode; a signal transmission feeder line with a shielding layer, wherein the signal transmission feeder line is connected with multi-path data output ends of the follower circuits; a multi-path data input end of the analog channel is connected with the signal transmission feeder line; a multichannel data input end of the multichannel high-precision analog-to-digital converter is connected with a multichannel data output end of the analog channel; the resolution of the analog-to-digital converter is greater than or equal to 24 bits; and the microprocessor is connected with the analog-to-digital converter. According to the invention, the signal-to-noise ratio of the signal acquired by the dry electrode is improved through the cooperation of all the components, and the quality and accuracy of the acquired signal are guaranteed.

Description

Technical Field

[0001] The present application relates to the field of bioelectricity acquisition technology, and in particular to a portable multi-channel bioelectricity acquisition system. Background Art

[0002] Bioelectric signal acquisition is a crucial technical tool in clinical neurological research. The quality of the signals collected by the signal acquisition system directly impacts the reliability of the system and the accuracy of subsequent disease diagnosis. Furthermore, bioelectric signal acquisition systems can also be applied to brain-computer interfaces, controlling intelligent devices or analyzing human physiological characteristics. This also requires high accuracy in bioelectric acquisition equipment, otherwise misjudgment may occur.

[0003] While traditional dedicated biopotential collection devices offer good performance, they are bulky and require cables to connect the wearable device to a computer, hindering long-term use and real-time monitoring. Portable biopotential collection systems, on the other hand, offer advantages such as portability and adaptability, and are expected to be applicable in a variety of daily life scenarios.

[0004] Currently, portable biopotential collection systems use electrodes that are broadly categorized as wet electrodes and dry electrodes. Devices using wet electrodes require the user to inject a conductive fluid, such as conductive paste or saline, into the electrodes before wearing them. While this method yields good data collection results in a short period of time, it is time-consuming, requires washing hair before and after testing, and creates a poor wearing experience, which contradicts the convenient and fast use of portable devices.

[0005] Dry electrodes are more popular because they are easy to wear and reusable, which can overcome the shortcomings of wet electrodes and provide a better user experience. However, the inventors realized that the contact impedance between dry electrodes and human skin is high, and the bioelectric signals are very weak. If dry electrodes are simply used to collect bioelectric signals and there is a lack of further processing circuits for the signals collected by dry electrodes, the accuracy of signal collection will be greatly reduced, and the signal-to-noise ratio will be relatively low, making it difficult to ensure the quality of the collected signals, limiting its effectiveness in practical applications. Even in medical applications, the poor quality of bioelectric signals collected by dry electrodes can lead to misjudgment of signal analysis, resulting in serious consequences. Utility Model Content

[0006] The present application provides a high-precision portable multi-channel bioelectric acquisition system based on dry electrodes, which aims to solve the problem that existing dry electrode portable bioelectric acquisition equipment is difficult to ensure the quality of the acquired signals.

[0007] A high-precision portable multi-channel bioelectrical acquisition system based on dry electrodes, comprising:

[0008] Multiple integrated dry electrodes are respectively arranged at multiple parts of the human body to be collected; each integrated dry electrode includes a collection dry electrode and a follower circuit, the collection dry electrode is used to collect bioelectrical signals from the corresponding part to be collected, and the data input end of the follower circuit is electrically connected to the data output end of the corresponding collection dry electrode;

[0009] A signal transmission feeder electrically connected to the multi-channel data output terminals of the plurality of follower circuits; the signal transmission feeder having a shielding layer;

[0010] an analog channel, wherein the multiple data input terminals are electrically connected to the signal transmission feeder;

[0011] a multi-channel high-precision analog-to-digital converter, wherein the multi-channel data input terminals are electrically connected to the multi-channel data output terminals of the analog channels; the resolution of the multi-channel high-precision analog-to-digital converter is greater than or equal to 24 bits;

[0012] A microprocessor is bidirectionally connected to the multi-channel high-precision analog-to-digital converter.

[0013] In the above solution, optionally, the collection dry electrode is a gel electrode, a claw electrode, a comb electrode or a flexible electrode.

[0014] In the above scheme, optionally, the follower circuit includes an operational amplifier U1, the non-inverting input pin of the operational amplifier U1 is electrically connected to the data output end of the corresponding acquisition dry electrode, and the inverting input pin and output pin of the operational amplifier U1 are both electrically connected to the signal transmission feeder through a resistor R.

[0015] In the above solution, optionally, the analog channel includes a low noise amplifier and / or a filter.

[0016] In the above solution, optionally, the model of the multi-channel high-precision analog-to-digital converter is ADS1299, ADSD1299 or LH001-99.

[0017] In the above solution, optionally, the multi-channel bioelectric acquisition system is provided with a plurality of multi-channel high-precision analog-to-digital converters, and the plurality of multi-channel high-precision analog-to-digital converters are cascaded.

[0018] In the above scheme, optionally, a programmable amplifier is integrated inside the multi-channel high-precision analog-to-digital converter, and the multi-channel high-precision analog-to-digital converter can adjust the amplification gain of the programmable amplifier according to a first control command sent by the microprocessor; and / or the multi-channel high-precision analog-to-digital converter can adjust the sampling frequency of the analog-to-digital conversion according to a second control command sent by the microprocessor.

[0019] In the above scheme, further optionally, the multi-channel bioelectric acquisition system also includes a wireless communication module, which is bidirectionally connected to the microprocessor for communication, and the wireless communication module is used to establish a wireless communication connection with an external device; or the microprocessor is an ARM processor with an integrated wireless communication function, and the ARM processor can establish a wireless communication connection with an external device.

[0020] In the above scheme, further optionally, the multi-channel high-precision analog-to-digital converter has a built-in bias drive amplifier, and the multi-channel bioelectric acquisition system also includes a drive circuit, the drive circuit includes a capacitor C1, a resistor R1 and a resistor R2, the BIASOUT pin and the BIASINV pin of the multi-channel high-precision analog-to-digital converter are electrically connected through the parallel capacitor C1 and the resistor R1, the BIASOUT pin of the multi-channel high-precision analog-to-digital converter is electrically connected to the drive dry electrode through the resistor R2, and the drive dry electrode is connected to the human skin.

[0021] Compared with the prior art, this application has at least the following beneficial effects:

[0022] 1. The embodiment of the present application provides a new hardware architecture of a portable multi-channel bioelectric acquisition system. On the basis of using dry electrodes to collect bioelectric signals, a follower circuit, a signal transmission feeder with a shielding layer and a high-precision ADC with a resolution of not less than 24 bits are added at the same time; wherein the follower circuit eliminates the influence of the large contact resistance between the dry electrode and the human body on the signal through the high input impedance and low output impedance characteristics of the operational amplifier, thereby enhancing the signal-to-noise ratio of the dry electrode collected signal, reducing the signal attenuation caused by impedance, and improving the load capacity; the signal transmission feeder can shield electromagnetic interference in the environment, as well as the signal crosstalk between each lead, reducing the influence of noise on the quality of the collected signal, and improving the quality of the collected signal and anti-interference performance; the model The pseudo-channel can amplify and / or filter the collected signal, ensuring that the signal reaches the appropriate amplitude before entering the analog-to-digital converter, while filtering out irrelevant components, improving the clarity and availability of the signal, facilitating ADC acquisition, and thus improving acquisition accuracy; selecting a multi-channel ADC with a resolution of not less than 24 bits can achieve high-precision digital signal acquisition; through the mutual cooperation of various components, the signal-to-noise ratio of the bioelectric signal collected by the dry electrode is improved, the quality and accuracy of the collected signal are guaranteed, and together high-precision acquisition of the bioelectric signal is achieved, achieving the purpose of improving the precision and accuracy of the bioelectric acquisition system; this portable multi-channel bioelectric acquisition system can obtain high-quality bioelectric signals in actual applications, providing more accurate data support for brain-computer interfaces and neurodiagnosis.

[0023] 2. In the hardware architecture provided in this application, a driving circuit is also added, and the driving circuit is connected to the BIASOUT pin of the driving dry electrode and the multi-channel high-precision analog-to-digital converter; on the one hand, the driving circuit and each dry electrode are used in conjunction to realize the electrode connectivity detection function, allowing real-time monitoring of the contact status of each dry electrode with the human body, and detecting whether each integrated dry electrode is in good contact with the human body, thereby ensuring a good connection and avoiding data errors caused by poor contact, thereby further improving the reliability of data acquisition; on the other hand, due to the potential difference between the subject's body and the surrounding environment, common-mode interference may be generated. The integrated driving circuit can effectively suppress baseline drift and stabilize the bioelectric signal near a relatively constant baseline, while effectively reducing the common-mode interference of multiple channels and improving the common-mode rejection ratio of the system.

[0024] 3. Based on the hardware architecture provided in this application, the microprocessor can also adjust the sampling frequency and amplification gain of the ADC as needed. This flexibility enables the system to adapt to different application scenarios and further improve real-time performance and accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic diagram of the module structure of a high-precision portable multi-channel bioelectrical potential acquisition system based on dry electrodes provided in one embodiment of the present application;

[0026] Figure 2 This is a detailed module structure diagram of a high-precision portable multi-channel bioelectrical potential acquisition system based on dry electrodes in one embodiment of the present application;

[0027] Figure 3 This is a schematic diagram of a follower circuit in an integrated dry electrode according to one embodiment of the present application;

[0028] Figure 4 This is a schematic diagram of the complete module structure of a high-precision portable multi-channel bioelectrical potential acquisition system based on dry electrodes in one embodiment of the present application;

[0029] Figure 5 This is a schematic diagram of a driving circuit in one embodiment of the present application;

[0030] Figure 6 This is a connection diagram of an ADC built-in bias driver amplifier in one embodiment of the present application;

[0031] Figure 7 This is a complete schematic diagram of a driving circuit in one embodiment of the present application;

[0032] Figure 8 This is another complete module structure diagram of a high-precision portable multi-channel bioelectrical potential acquisition system based on dry electrodes in one embodiment of the present application;

[0033] Figure 9 This is a schematic diagram of a cascade connection method for multiple ADCs in one embodiment of the present application;

[0034] Figure 10 This is a schematic diagram of a circuit system of a high-precision portable multi-channel bioelectrical potential acquisition system based on dry electrodes in one embodiment of the present application;

[0035] Figure 11 A flowchart of a control method for a high-precision portable multi-channel bioelectric acquisition system provided in one embodiment of the present application.

[0036] Description of reference numerals:

[0037] 1. Integrated dry electrode; 11. Data acquisition dry electrode; 12. Follower circuit; 2. Signal transmission feeder; 3. Analog channel; 4. Multi-channel high-precision analog-to-digital converter; 5. Microprocessor; 6. Wireless communication module; 7. Drive circuit; 8. Drive dry electrode. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0039] In the description of this application: unless otherwise specified, the meaning of "plurality" is two or more. The terms "first", "second", "third", etc. in this application are intended to distinguish the objects referred to and do not have any special meaning in terms of technical connotation (for example, they should not be understood as emphasizing the importance or order, etc.). Expressions such as "including", "comprising", "having", etc. also mean "not limited to" (certain units, components, materials, steps, etc.).

[0040] In one embodiment, a high-precision portable multi-channel bioelectrical acquisition system based on dry electrodes is provided. Figure 1 and Figure 2 As shown, it includes:

[0041] Multiple integrated dry electrodes 1 are respectively arranged at multiple parts of the human body to be collected; each integrated dry electrode 1 includes a collection dry electrode 11 and a follower circuit 12, the collection dry electrode 11 is used to collect bioelectrical signals from the corresponding part to be collected, and the data input end of the follower circuit 12 is electrically connected to the data output end of the corresponding collection dry electrode 11;

[0042] The signal transmission feeder 2 is electrically connected to the multi-channel data output terminals of the multiple follower circuits 12; the signal transmission feeder 2 is a transmission feeder with a shielding layer;

[0043] The analog channel 3 has its multiple data input terminals electrically connected to the signal transmission feeder 2. In other words, the multiple data input terminals of the analog channel 3 are electrically connected to the multiple data output terminals of the multiple follower circuits 12 through the signal transmission feeder 2.

[0044] a multi-channel high-precision analog-to-digital converter (ADC) 4, wherein the multi-channel data input terminals are electrically connected to the multi-channel data output terminals of the analog channel 3; the resolution of the multi-channel high-precision analog-to-digital converter 4 is greater than or equal to 24 bits, thereby ensuring that the multi-channel high-precision analog-to-digital converter 4 is a high-precision multi-channel analog-to-digital converter;

[0045] The microprocessor 5 is bidirectionally connected to the multi-channel high-precision analog-to-digital converter 4, that is, the control signal output end of the microprocessor 5 is electrically connected to the control signal input end of the multi-channel high-precision analog-to-digital converter 4, and the data input end of the microprocessor 5 is electrically connected to the data output end of the multi-channel high-precision analog-to-digital converter 4.

[0046] In this multi-channel biopotential collection system, the integrated dry electrode 1 consists of two parts: a collection dry electrode 11 and a follower circuit 12. The collection dry electrode 11 is in direct contact with human skin to receive human biopotential signals. Specifically, it can be implemented by a gel electrode, a claw electrode, a comb electrode, a flexible electrode, etc.

[0047] Follower circuit 12 is electrically connected to the collection electrode 11 and is used to improve the signal-to-noise ratio and interference resistance of the bioelectrical signals collected by the collection electrode 11. Because the impedance between the collection electrode 11 and the human body is large, it can easily lead to poor signal-to-noise ratio. Therefore, an active follower is added between the collection electrode 11 and the transmission feeder.

[0048] The follower can be realized by an operational amplifier, the collection dry electrode 11 is connected to the positive input terminal of the operational amplifier, and the output terminal and the negative input terminal of the operational amplifier are electrically connected to the transmission feeder through a protective resistor. The schematic diagram of the follower circuit 12 is as follows Figure 3 As shown, that is to say:

[0049] The follower circuit 12 includes an operational amplifier U1 , whose inverting input pin is electrically connected to the data output terminal of the corresponding acquisition dry electrode 11 , and whose inverting input pin and output pin are both electrically connected to the signal transmission feeder 2 via a resistor R.

[0050] By utilizing the high input impedance and low output impedance characteristics of the operational amplifier, the follower circuit 12 can enhance the signal-to-noise ratio of the collected signal and improve the load capacity. At the same time, the follower circuit can also play the role of isolating the front-end and back-end signals.

[0051] In the bioelectrical acquisition system, a feeder with a shielding layer is used to shield electromagnetic interference in the environment, as well as crosstalk between signals of various leads, thereby reducing noise.

[0052] In other words, the signal feeder is preferably a shielded feeder, used to connect the collection dry electrodes 11 and the analog channel 3, transmitting the bioelectrical signals received by each collection dry electrode 11 to the analog channel 3, while also shielding against external electromagnetic interference and inter-channel signal interference. The shielding layer is connected to the ground level of the circuit system.

[0053] Furthermore, the analog channel 3 may specifically include a low noise amplifier and / or a filter:

[0054] The low-noise amplifier is used to amplify the bioelectrical signals of each channel;

[0055] Filters are used to remove various irrelevant components in bioelectric signals.

[0056] Bioelectric signals often have low amplitudes. Using the amplifier in analog channel 3 can uniformly amplify the signals to a certain amplitude, making them easier for ADC acquisition and improving measurement accuracy. A low-noise amplifier or instrumentation amplifier is preferred.

[0057] In this bioelectrical potential acquisition system, a multi-channel, high-precision analog-to-digital converter (ADC) 4 is connected to analog channels 3 and a microprocessor 5, with a sampling resolution of no less than 24 bits, enabling high-precision sampling of multiple analog channels 3. Specifically, the model of multi-channel, high-precision ADC 4 can be ADS1299, ADSD1299, or LH001-99.

[0058] Furthermore, the multi-channel high-precision analog-to-digital converter 4 has a programmable amplifier integrated inside, and the multi-channel high-precision analog-to-digital converter 4 can adjust the amplification gain of the programmable amplifier according to the first control command sent by the microprocessor 5; and / or the multi-channel high-precision analog-to-digital converter 4 can adjust the sampling frequency of the analog-to-digital conversion according to the second control command sent by the microprocessor 5.

[0059] like Figure 4 As shown, the multi-channel bioelectric acquisition system also includes a wireless communication module 6, which is bidirectionally connected to the microprocessor 5, and the wireless communication module 6 is used to establish a wireless communication connection with an external device; or the microprocessor 5 is an ARM processor with an integrated wireless communication function, and the ARM processor can establish a wireless communication connection with an external device.

[0060] The external device can be a remote processor, a computer, or a cloud server. The microprocessor 5 can be an ARM processor with integrated wireless communication capabilities, such as the ESP32 series chips. This allows signals to be sent directly to the external device via Wi-Fi or Bluetooth, improving system integration and reducing power consumption.

[0061] That is to say, the high-precision ADC has a programmable amplifier (PGA) integrated therein, which can adjust the amplification gain according to the control command of the microprocessor 5, thereby achieving controllable amplification of the analog signal and improving the signal acquisition accuracy.

[0062] In the bioelectrical data acquisition system, the microprocessor (MCU) 5 is used to control the entire system to coordinate operations according to application requirements. Specifically, it can control the sampling clock of the ADC and adjust the sampling frequency according to application requirements to achieve high time precision sampling.

[0063] As an optional configuration, the microprocessor 5 can also perform operations on the collected digital signals according to commands from the external device, such as digital filtering and / or feature extraction. The microprocessor 5 preferably transmits the collected bioelectric digital signals to the external device under the control of the external device.

[0064] Furthermore, the multi-channel high-precision analog-to-digital converter 4 may also be internally provided with a bias drive amplifier, such as Figure 4 As shown, the multi-channel bioelectrical acquisition system further includes a driving circuit 7, as shown in FIG. Figure 5 As shown, the driving circuit 7 includes a capacitor C1, a resistor R1 and a resistor R2. The BIASOUT pin and the BIASINV pin of the multi-channel high-precision analog-to-digital converter 4 are electrically connected through the capacitor C1 and the resistor R1 in parallel. The BIASOUT pin of the multi-channel high-precision analog-to-digital converter 4 is electrically connected to the driving dry electrode 8 through the resistor R2, and the driving dry electrode 8 is connected to the human skin.

[0065] The collection dry electrode 11 and the driving dry electrode 8 are both dry electrodes, but they are located in different positions and have different functions. The two dry electrodes can be the same electrode, or they can have different shapes due to different fixing methods. The driving dry electrode 8 can generally be a suction cup electrode or an electrode clamp.

[0066] In other words, the drive circuit 7 is connected to the driving dry electrode 8 and the BIASOUT pin of the multi-channel high-precision analog-to-digital converter 4. The BIASOUT pin is the output of the bias drive amplifier. The drive circuit 7 includes a resistor and capacitor network. The BIASINV pin of the analog-to-digital converter is connected to the BIASOUT pin via a parallel resistor and capacitor, and the BIASOUT pin is connected to the driving dry electrode 8 via a resistor. The drive circuit 7 can suppress common-mode interference and detect dry electrode continuity.

[0067] Due to the addition of the drive circuit 7, the electrode connectivity detection function can be realized by cooperating with the drive circuit 7 and each dry electrode acquisition circuit. The drive circuit 7 can detect whether each dry electrode is in good contact with the human body. The electrode connectivity detection function can be used to check whether each dry electrode is in good contact with the human body, avoiding the impact of poor contact on the detection effect. In addition, the drive circuit 7 can also suppress common mode interference. Specifically:

[0068] The connectivity detection function is implemented by a high-precision ADC outputting a specific current or voltage signal from the Biasout port via an internal bias driver amplifier. This signal is then fed through a driver circuit 7 to a driver dry electrode 8. Driver dry electrode 8 can be connected to the mastoid process, earlobe, top of the head, or forehead. After the signal enters the body, the return signal from each integrated detection dry electrode is monitored. If the integrated dry electrode 1 is properly connected to the skin, a stable signal is detected. If the connection is broken or poor, the signal will fluctuate.

[0069] In other words, a specific current or voltage is transmitted to the human body via the driving circuit 7. If the connection between the acquisition dry electrodes 11 and the body is good, this specific current or voltage can be conducted through the body to each acquisition dry electrode 11 and then detected by the ADC. If the connection is poor, the specific current or voltage cannot be transmitted back. In theory, the driving dry electrodes 8 should be appropriately away from the area of ​​the acquisition dry electrodes 11; in practice, the position can be adjusted according to actual conditions.

[0070] On the other hand, since the driving circuit 7 is connected to the bias driving amplifier built in the high-precision ADC, a voltage signal can be sent to the user's body surface to suppress common-mode interference. Figure 6 As shown in the figure, as an optional configuration, by configuring the internal registers of the high-precision ADC, the common-mode signals of the EEG signals of each channel are uniformly superimposed and connected to the negative terminal of the built-in driver amplifier. After comparison with the internal reference voltage, the inverted feedback is fed back to the output terminal, generating a voltage with the opposite polarity of the interference signal, which is injected into the subject's body. This can offset the common-mode interference coupled between each channel and the human body and improve the common-mode rejection ratio of the system.

[0071] The resistor R1 and capacitor C1 connected in parallel in the driving circuit 7 are used to adjust the response speed and stability of the driving circuit 7. The output protection resistor R2 plays a role in protecting the circuit to avoid damage to the chip caused by external short circuits or damage to the human body caused by large currents generated by chip failures. Figure 7 As shown, TVS tubes D1 and D2 may be preferably added to protect the circuit and the human body from damage caused by transient voltage shocks such as overvoltage, electromagnetic pulse (EMP), and electrostatic discharge (ESD).

[0072] In summary, the embodiment of the present application provides a high-precision portable multi-channel bioelectrical potential acquisition system based on dry electrodes, including:

[0073] Several integrated dry electrode modules are arranged in various parts of the human body to receive bioelectric signals from the human body; the bioelectric signals are mainly EEG and / or EOG signals;

[0074] Signal transmission feeder 2, connecting the integrated dry electrodes 1 worn at various locations on the human body and the analog channels 3 in the circuit system, for transmitting bioelectrical signals from the integrated dry electrodes 1 at various locations to the analog channels 3;

[0075] Analog channel 3, used to amplify and / or filter each bioelectric signal;

[0076] A multi-channel high-precision analog-to-digital converter (ADC) 4 is used to synchronously and accurately acquire the analog signals output by the analog channels 3 and convert the analog signals into digital signals that are easy to process; the ADC is controlled by a subsequent microprocessor 5;

[0077] The microprocessor 5 is connected to the ADC and is used to control the coordinated work of the entire system according to the needs of the application and to communicate with external devices. According to the commands of the external devices, the collected bioelectric digital signals are processed or sent to the external devices.

[0078] Its complete structure also includes a wireless communication module 6 and a driving circuit 7. That is to say, the complete structure of the high-precision portable multi-channel bioelectric acquisition system based on dry electrodes includes an integrated dry electrode 1, a feeder with a shielding layer, an analog channel 3, a multi-channel high-precision ADC, a microprocessor 5, a wireless communication module 6 and a driving circuit 7. The complete structural diagram can also be seen in Figure 8 .

[0079] The portable multi-channel biopotential acquisition system based on dry electrodes provided in the embodiments of the present application solves the signal accuracy problem of portable biopotential acquisition devices through multiple components:

[0080] (1) Due to the large impedance between the dry electrode and the human body, the signal-to-noise ratio is likely to be poor. Therefore, a follower is added between the dry electrode and the transmission feeder. The high input impedance and low output impedance characteristics of the operational amplifier are utilized to enhance the signal-to-noise ratio and improve the load capacity.

[0081] (2) Use a feeder with a shielding layer to shield electromagnetic interference in the environment and crosstalk between signals of each lead to reduce noise.

[0082] (3) Bioelectric signals often have low amplitudes. The amplifier of analog channel 3 can be used to uniformly amplify the signals to a certain amplitude, which is convenient for ADC acquisition and thus improves measurement accuracy.

[0083] (4) Filters can be used to remove unwanted out-of-band noise and improve the signal-to-noise ratio.

[0084] (5) By setting up the driving circuit 7, the electrode connectivity detection function can be used to check whether each dry electrode is well connected to the human body, thereby avoiding the influence of poor contact on the detection effect.

[0085] (6) The driving circuit 7 can be used to reversely feed the common-mode interference of each electrode into the human body, thereby suppressing the common-mode interference of each channel.

[0086] By utilizing the above key technologies and ensuring the quality of the detection signal, this system uses a high-precision analog-to-digital converter of at least 24 bits to collect analog signals, thereby achieving the purpose of improving the accuracy of the bioelectric acquisition system.

[0087] Preferably, the ADC uses a high-precision ADC dedicated to bioelectricity, such as ADS1299, ADSD1299, etc. This chip has the advantages of low noise, high common mode rejection ratio, multi-channel synchronous sampling, and low power consumption.

[0088] According to the needs of actual application, multiple ADCs can be cascaded to increase the number of channels. That is to say, the multi-channel high-precision analog-to-digital converter 4 in the multi-channel bioelectric acquisition system can be provided with multiple, multiple multi-channel high-precision analog-to-digital converters 4 can be cascaded, and the cascade method is as follows: Figure 9 As shown in the figure, the ADC integrates a programmable amplifier (PGA) that can controllably adjust the amplification factor of a certain signal according to the instructions of the microprocessor 5, thereby further improving the signal sampling accuracy. The ADC also integrates a digital sampling filter that can controllably low-pass filter the input signal to prevent spectrum aliasing.

[0089] In addition, based on the hardware architecture provided by this application, the sampling frequency of the ADC in this system can be controlled by the microprocessor 5. When collecting higher-frequency bioelectric signals or when external devices have high real-time requirements, the ADC can be controlled to use a higher frequency for analog-to-digital conversion. When collecting lower-frequency signals or when external devices do not require real-time performance, a slower sampling frequency can be used for analog-to-digital conversion to reduce redundant data and achieve better time accuracy.

[0090] By setting up various components in the above multi-channel biopotential acquisition system, the system structure and device performance are optimized, the signal quality is effectively improved, the signal sampling amplitude accuracy and time accuracy are improved, and a high-precision dry electrode biopotential acquisition system is realized. The circuit system schematic diagram can be found in Figure 10 .

[0091] The portable, multi-channel biopotential acquisition system based on dry electrodes provided in the present application has a high level of system integration and low power consumption. This allows for improved signal amplitude and timing accuracy while maintaining portability, comfort, and convenience. This facilitates long-term wear by subjects and accurate detection of biopotential signals, improving the accuracy of brain-computer interfaces and neurodiagnostic analysis, and reducing the likelihood of misjudgment and misdiagnosis.

[0092] The embodiment of the present application provides a new hardware architecture of a portable multi-channel bioelectric acquisition system. On the basis of using dry electrodes to collect bioelectric signals, a follower circuit, a signal transmission feeder with a shielding layer, and a high-precision ADC with a resolution of not less than 24 bits are added at the same time; wherein the follower circuit eliminates the influence of the large contact resistance between the dry electrode and the human body on the signal through the high input impedance and low output impedance characteristics of the operational amplifier, thereby enhancing the signal-to-noise ratio of the dry electrode acquisition signal, reducing the signal attenuation caused by impedance, and improving the load capacity; the signal transmission feeder can shield electromagnetic interference in the environment, as well as shield the signal crosstalk between each lead, reducing noise The impact on the quality of the collected signal improves the quality and anti-interference of the collected signal; the analog channel can amplify and / or filter the collected signal, ensuring that the signal reaches the appropriate amplitude before entering the analog-to-digital converter, while filtering out irrelevant components, improving the clarity and availability of the signal, facilitating ADC collection, and thus improving the collection accuracy; selecting a multi-channel ADC with a resolution of not less than 24 bits can achieve high-precision digital signal collection; through the mutual cooperation of various components, the signal-to-noise ratio of the dry electrode collected bioelectric signal is improved, the quality and accuracy of the collected signal are guaranteed, and together high-precision collection of bioelectric signals is achieved, so as to achieve the purpose of improving the precision and accuracy of the bioelectric collection system.

[0093] At the same time, the added drive circuit can realize the electrode connectivity detection function, allowing real-time monitoring of the contact status of each dry electrode with the human body, ensuring a good connection and avoiding data errors caused by poor contact, thereby further improving the reliability of data acquisition. Due to the potential difference between the subject's body and the surrounding environment, common-mode interference may be generated. The integrated drive circuit can also effectively suppress baseline drift, stabilizing the bioelectrical signal near a relatively constant baseline, while effectively reducing multi-channel common-mode interference.

[0094] In addition, based on the hardware architecture provided in this application, the microprocessor can adjust the sampling frequency and amplification gain of the ADC as needed. This flexibility enables the system to adapt to different application scenarios and further improve real-time performance and accuracy.

[0095] In summary, this solution effectively overcomes the dry electrode signal accuracy problem existing in the background technology through reasonable system architecture design and configuration of high-performance components. This portable multi-channel biopotential acquisition system can obtain high-quality biopotential signals in practical applications, providing more accurate data support for brain-computer interfaces and neurodiagnosis.

[0096] In other words, the embodiment of the present application provides a high-precision portable multi-channel bioelectric acquisition system based on dry electrodes, which includes: signal acquisition dry electrodes for fitting to key positions of the human body to capture and conduct bioelectric signals from various parts of the human body; a transmission feeder with a shielded layer for conducting the bioelectric signals captured by the dry electrodes to the analog channel; an instrument amplifier in the analog channel uses the signal to accurately amplify the signal; a filter is used to filter out noise interference and low-frequency drift in the signal; a multi-channel high-precision analog-to-digital converter is connected to the output end of the analog channel for high-precision acquisition of multi-channel bioelectric signals as digital signals; a controller is connected to the high-precision analog-to-digital converter for receiving digital signals and processing the signals; a wireless communication module is connected to the controller for sending the collected signals to a remote device (processor, computer or cloud platform). The system can achieve high-precision acquisition of bioelectric signals, improve signal quality, improve the overall signal-to-noise ratio while ensuring the portability and low power consumption of the system, and optimize the recognition rate of the brain-computer interface and the reliability of bioelectric signal analysis.

[0097] This multi-channel biopotential acquisition system is a high-precision portable multi-channel biopotential acquisition system that improves the measurement accuracy of dry electrodes. While ensuring the portability and ease of wearing of the equipment, it solves the signal accuracy problem of current dry electrode portable biopotential acquisition equipment.

[0098] In one embodiment, Figure 11 As shown, a control method for a portable multi-channel biopotential acquisition system is provided. The method is described by taking the portable multi-channel biopotential acquisition system based on dry electrodes provided in the above embodiment as an example, and includes the following steps:

[0099] S1, using the driving circuit to detect whether each integrated dry electrode is tightly connected to each part of the human body to be collected;

[0100] S2, if it is detected that the integrated dry electrode is not tightly connected to the corresponding part to be collected, the microprocessor sends a corresponding prompt message to the external device;

[0101] That is to say, if it is found that some dry electrodes are not tightly connected to the human body, the microprocessor can send a signal to prompt the user to adjust the wearing;

[0102] S3, if it is detected that all are tightly connected, the microprocessor receives a control signal from the external device and sends a first control command and / or a second control command to the multi-channel high-precision analog-to-digital converter to adjust the amplification gain and / or sampling frequency of the multi-channel high-precision analog-to-digital converter, so that the portable multi-channel bioelectrical acquisition system acquires bioelectrical signals at a target amplification gain and / or target sampling frequency;

[0103] S4, the microprocessor receives the bioelectrical signals collected by each integrated dry electrode and performs calculations on the collected bioelectrical signals;

[0104] S5, the microprocessor sends the calculation result to the external device.

[0105] In simple terms, the method involves:

[0106] Check whether each dry electrode is tightly connected to the human body;

[0107] Receive control instructions from external devices;

[0108] Use appropriate amplification and sampling rate to collect bioelectric signals;

[0109] Perform certain calculations on the collected bioelectric digital signals;

[0110] Transfer it to an external device.

[0111] It should be understood that although Figure 8 The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. In addition, Figure 8 At least part of the steps may include multiple steps or multiple stages. These steps or stages are not necessarily performed at the same time, but can be performed at different times. The order of execution of these steps or stages is not necessarily one by one, but can be performed in turn or alternately with other steps or at least part of the steps or stages in other steps.

[0112] The technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. A high-precision portable multi-channel bioelectrical acquisition system based on dry electrodes, characterized in that: include: Multiple integrated dry electrodes are respectively arranged at multiple parts of the human body to be collected; each integrated dry electrode includes a collection dry electrode and a follower circuit, the collection dry electrode is used to collect bioelectrical signals from the corresponding part to be collected, and the data input end of the follower circuit is electrically connected to the data output end of the corresponding collection dry electrode; A signal transmission feeder electrically connected to the multi-channel data output terminals of the plurality of follower circuits; the signal transmission feeder having a shielding layer; an analog channel, wherein the multiple data input terminals are electrically connected to the signal transmission feeder; a multi-channel high-precision analog-to-digital converter, wherein the multi-channel data input terminals are electrically connected to the multi-channel data output terminals of the analog channels; the resolution of the multi-channel high-precision analog-to-digital converter is greater than or equal to 24 bits; A microprocessor is bidirectionally connected to the multi-channel high-precision analog-to-digital converter.

2. The high-precision portable multi-channel bioelectrical acquisition system based on dry electrodes according to claim 1 is characterized in that: The collection dry electrode is a gel electrode, a claw electrode, a comb electrode or a flexible electrode.

3. The high-precision portable multi-channel bioelectrical acquisition system based on dry electrodes according to claim 1 is characterized in that: The follower circuit includes an operational amplifier U1, the non-inverting input pin of the operational amplifier U1 is electrically connected to the data output terminal of the corresponding acquisition dry electrode, and the inverting input pin and output pin of the operational amplifier U1 are both electrically connected to the signal transmission feeder through a resistor R.

4. The high-precision portable multi-channel bioelectrical acquisition system based on dry electrodes according to claim 1, characterized in that: The analog channel includes a low noise amplifier and / or a filter.

5. The high-precision portable multi-channel bioelectrical acquisition system based on dry electrodes according to claim 1, characterized in that: The model of the multi-channel high-precision analog-to-digital converter is ADS1299, ADSD1299 or LH001-99.

6. The high-precision portable multi-channel bioelectrical potential acquisition system based on dry electrodes according to claim 1, characterized in that: The multi-channel bioelectricity acquisition system is provided with a plurality of multi-channel high-precision analog-to-digital converters, and the plurality of multi-channel high-precision analog-to-digital converters are cascaded.

7. The high-precision portable multi-channel bioelectrical acquisition system based on dry electrodes according to claim 1, characterized in that: The multi-channel high-precision analog-to-digital converter has a programmable amplifier integrated therein, and the multi-channel high-precision analog-to-digital converter can adjust the amplification gain of the programmable amplifier according to a first control command sent by the microprocessor; and / or the multi-channel high-precision analog-to-digital converter can adjust the sampling frequency of the analog-to-digital conversion according to a second control command sent by the microprocessor.

8. The high-precision portable multi-channel bioelectrical potential acquisition system based on dry electrodes according to claim 7, characterized in that: The multi-channel bioelectric acquisition system also includes a wireless communication module, which is bidirectionally connected to the microprocessor for communication, and the wireless communication module is used to establish a wireless communication connection with an external device; or the microprocessor is an ARM processor with an integrated wireless communication function, and the ARM processor can establish a wireless communication connection with an external device.

9. The high-precision portable multi-channel bioelectrical potential acquisition system based on dry electrodes according to claim 8, characterized in that: The multi-channel high-precision analog-to-digital converter has a built-in bias drive amplifier, and the multi-channel bioelectric acquisition system also includes a drive circuit, which includes a capacitor C1, a resistor R1 and a resistor R2. The BIASOUT pin and the BIASINV pin of the multi-channel high-precision analog-to-digital converter are electrically connected through the parallel capacitor C1 and the resistor R1. The BIASOUT pin of the multi-channel high-precision analog-to-digital converter is electrically connected to the drive dry electrode through the resistor R2, and the drive dry electrode is connected to the human skin.

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