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

Abstract

The invention 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 and a control method thereof. Background Art

[0002] Bioelectric signal acquisition is an important technical means for clinical neuromedical research. The quality of the signals collected by the signal acquisition system will directly affect the reliability of the system and the accuracy of subsequent disease judgment. In addition, the bioelectric signal acquisition system can also be applied to the field of brain-computer interface to control smart terminals or analyze human physiological characteristics, which also requires the bioelectric acquisition equipment to have good accuracy, otherwise it may cause misjudgment.

[0003] Although traditional dedicated bioelectricity collection equipment has good performance, it is bulky and requires cables to connect the collection equipment worn by the user to the computer, which is not conducive to long-term use and real-time monitoring by the user. The portable bioelectricity collection system has the advantages of being easy to carry and highly adaptable, and is expected to be used in various life scenarios.

[0004] At present, the types of electrodes used in portable bioelectrical collection systems are generally divided into wet electrodes and dry electrodes. When the device using wet electrodes is worn by the user, conductive liquids such as conductive paste and saline need to be injected into the electrodes. Although this can achieve better collection results in a short period of time, it takes a long time, requires washing hair before and after the test, and has a poor wearing experience, which is inconsistent with the convenient and fast application method of portable devices.

[0005] Dry electrodes are more popular because they are easy to wear, reusable, and can overcome the defects of wet electrodes, providing a better user experience. However, the inventors realized that the contact impedance between dry electrodes and human skin is relatively high, and the bioelectric signals are very weak. If dry electrodes are used to collect bioelectric signals without 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. Summary of the invention

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

[0007] In the first aspect, a high-precision portable multi-channel bioelectric acquisition system based on dry electrodes comprises:

[0008] A plurality of integrated dry electrodes are respectively arranged at a plurality of parts of the human body to be collected; each integrated dry electrode comprises a collection dry electrode and a follower circuit, the collection dry electrode is used to collect the bioelectrical signal of 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 line is electrically connected to the multi-channel data output terminals of the multiple follower circuits; the signal transmission feeder line has a shielding layer;

[0010] An analog channel, whose multi-channel data input terminal is electrically connected to the signal transmission feeder;

[0011] A multi-channel high-precision analog-to-digital converter, whose 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 scheme, 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 in-phase 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 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, the multi-channel high-precision analog-to-digital converter has a programmable amplifier integrated inside, 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 human skin.

[0021] In a second aspect, a control method for a high-precision portable multi-channel bioelectric acquisition system is applied to the high-precision portable multi-channel bioelectric acquisition system based on dry electrodes described in the first aspect, and the method comprises:

[0022] The driving circuit is used to detect whether each integrated dry electrode is tightly connected to each part of the human body to be collected;

[0023] 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;

[0024] If it is detected that they are all tightly connected, the microprocessor receives a control signal from an external device, sends a first control command and / or a second control command to the multi-channel high-precision analog-to-digital converter, adjusts the amplification gain and / or sampling frequency of the multi-channel high-precision analog-to-digital converter, and enables the portable multi-channel bioelectric acquisition system to acquire bioelectric signals at a target amplification gain and / or a target sampling frequency;

[0025] The microprocessor receives the bioelectric signals collected by each integrated dry electrode and performs calculation processing on the collected bioelectric signals;

[0026] The microprocessor sends the calculation results to the external device.

[0027] Compared with the prior art, this application has at least the following beneficial effects:

[0028] 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 acquisition signal, reducing the signal attenuation caused by impedance, and improving the load capacity; the signal transmission feeder can shield the electromagnetic interference in the environment, as well as the signal crosstalk between each lead, thereby reducing the influence of noise on the quality of the acquisition signal, and improving the quality and anti-interference of the acquisition signal; the model The pseudo-channel can amplify and / or filter the collected signal, ensuring that the signal reaches an 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 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 collection of the bioelectric signal is achieved, achieving the purpose of improving the precision and accuracy of the bioelectric collection system; the portable multi-channel bioelectric collection system can obtain high-quality bioelectric signals in practical applications, providing more accurate data support for brain-computer interfaces and neurodiagnosis.

[0029] 2. In the hardware architecture provided in the present 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, by cooperating with the driving circuit and each dry electrode, the electrode connectivity detection function can be realized, 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 multi-channel common-mode interference and improving the common-mode rejection ratio of the system.

[0030] 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

[0031] Figure 1A schematic diagram of the module structure of a high-precision portable multi-channel bioelectric acquisition system based on dry electrodes provided in one embodiment of the present application;

[0032] Figure 2 A detailed schematic diagram of the module structure of a high-precision portable multi-channel bioelectric acquisition system based on dry electrodes in one embodiment of the present application;

[0033] Figure 3 This is a schematic diagram of a follower circuit in an integrated dry electrode in one embodiment of the present application;

[0034] Figure 4 This is a schematic diagram of the complete module structure of a high-precision portable multi-channel bioelectric acquisition system based on dry electrodes in one embodiment of the present application;

[0035] Figure 5 A schematic diagram of a driving circuit in one embodiment of the present application;

[0036] Figure 6 This is a connection diagram of a built-in bias drive amplifier of an ADC in one embodiment of the present application;

[0037] Figure 7 This is a complete schematic diagram of a driving circuit in one embodiment of the present application;

[0038] Figure 8 This is another complete module structure schematic diagram of a high-precision portable multi-channel bioelectric acquisition system based on dry electrodes in one embodiment of the present application;

[0039] Fig. 9 This is a schematic diagram of a connection method for cascading multiple ADCs in one embodiment of the present application;

[0040] Fig.10 This is a circuit system schematic diagram of a high-precision portable multi-channel bioelectric acquisition system based on dry electrodes in one embodiment of the present application;

[0041] Fig.11 A flowchart of a control method for a high-precision portable multi-channel bioelectric acquisition system provided in accordance with an embodiment of the present application.

[0042] Description of reference numerals:

[0043] 1. Integrated dry electrode; 11. Data collection 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. Driving circuit; 8. Driving dry electrode. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0045] 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 special meanings in terms of technical connotations (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.).

[0046] In one embodiment, a high-precision portable multi-channel bioelectric acquisition system based on dry electrodes is provided. Figure 1 and Figure 2 As shown, it includes:

[0047] A plurality of integrated dry electrodes 1 are respectively arranged at a plurality of parts of the human body to be collected; each integrated dry electrode 1 comprises a collection dry electrode 11 and a follower circuit 12, the collection dry electrode 11 is used to collect the bioelectrical signal of 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;

[0048] 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;

[0049] The analog channel 3, whose multiple data input end is electrically connected to the signal transmission feeder 2; in other words, the multiple data input end of the analog channel 3 is electrically connected to the multiple data output ends of the multiple follower circuits 12 through the signal transmission feeder 2;

[0050] A multi-channel high-precision analog-to-digital converter (ADC) 4, whose 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;

[0051] 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.

[0052] In the multi-channel bioelectric acquisition 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 bioelectric signals, and can be implemented by a gel electrode, a claw electrode, a comb electrode, a flexible electrode, etc.

[0053] The follower circuit 12 is electrically connected to the collection dry electrode 11, and is used to improve the signal-to-noise ratio and anti-interference performance of the bioelectric signal collected by the collection dry electrode 11. Since the impedance between the collection dry electrode 11 and the human body is large, it is easy to cause the problem of poor signal-to-noise ratio, so an active follower is added between the collection dry electrode 11 and the transmission feeder.

[0054] The follower circuit 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 electrode and the negative input terminal of the operational amplifier are electrically connected to the transmission feeder through a protective resistor. Figure 3 As shown, that is to say:

[0055] The follower circuit 12 includes an operational amplifier U1, a non-inverting input pin of the operational amplifier U1 is electrically connected to the data output terminal of the corresponding collection dry electrode 11, and an inverting input pin and an output pin of the operational amplifier U1 are electrically connected to the signal transmission feeder 2 through a resistor R.

[0056] By utilizing the characteristics of high input impedance and low output impedance of the operational amplifier, the follower circuit 12 can enhance the signal-to-noise ratio of the collected signal and improve the load carrying capacity. At the same time, the follower can also play the role of isolating the front and rear stage signals.

[0057] In the bioelectric acquisition system, a feeder with a shielding layer is used to shield electromagnetic interference in the environment, and can shield the crosstalk of signals between various leads, thereby reducing noise.

[0058] In other words, the signal feeder is preferably a feeder with a shielding layer, which is used to connect the collection dry electrodes 11 and the analog channel 3, transmit the bioelectric signals received by each collection dry electrode 11 to the analog channel 3, and at the same time play a role in shielding external electromagnetic signal interference and signal interference between channels. The shielding layer is connected to the ground level in the circuit system.

[0059] Furthermore, the analog channel 3 may specifically include a low noise amplifier and / or a filter:

[0060] The low noise amplifier is used to amplify the bioelectrical signals of each channel;

[0061] Filters are used to filter out various irrelevant components in bioelectric signals.

[0062] Bioelectric signals are often of low amplitude. The amplifier of analog channel 3 can be used to uniformly amplify the signal to a certain amplitude, which is convenient for ADC acquisition, thereby improving measurement accuracy. A low-noise amplifier or instrument amplifier is preferred.

[0063] In the bioelectric acquisition system, a multi-channel high-precision analog-to-digital converter (ADC) 4 is connected to the analog channel 3 and the microprocessor 5, and the sampling resolution is not less than 24 bits, so that high-precision sampling of multiple analog channels 3 can be achieved. The model of the multi-channel high-precision analog-to-digital converter 4 can be ADS1299, ADSD1299 or LH001-99.

[0064] 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.

[0065] 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 for communication, 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.

[0066] The external device may be a remote processor, a computer or a cloud server. The microprocessor 5 may be an ARM processor with integrated wireless communication function, such as an ESP32 series chip. Thus, the signal can be directly sent to the external device via WIFI or Bluetooth, which improves the system integration and reduces power consumption.

[0067] 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 realizing controllable amplification of the analog signal and improving the signal acquisition accuracy.

[0068] In the bioelectrical data collection system, the microprocessor (MCU) 5 is used to control the entire system to coordinate work according to the needs of the application. Specifically, it can control the sampling clock of the ADC, adjust the sampling frequency according to the needs of the application, and achieve high time precision sampling.

[0069] As an optional configuration, the microprocessor 5 can also perform operations on the collected digital signals according to the command of 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.

[0070] 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 bioelectric acquisition system also includes a driving circuit 7, such as 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.

[0071] The collection dry electrode 11 and the driving dry electrode 8 are both dry electrodes, but they are set in different positions and have different functions; the two dry electrodes can be the same electrode, or they can have different forms due to different fixing methods. The driving dry electrode 8 can generally be a suction cup electrode or an electrode clamp.

[0072] In other words, the driving 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, and the BIASOUT pin is the output end of the bias driving amplifier; the driving circuit 7 includes a resistor and a capacitor network. The BIASINV pin of the analog-to-digital converter is connected to the BIASOUT pin with a resistor and a capacitor in parallel, and the BIASOUT pin is connected to the driving dry electrode 8 with a resistor. The driving circuit 7 can realize the functions of suppressing common-mode interference and detecting the connection of the dry electrode.

[0073] Since the driving circuit 7 is added, the driving circuit 7 and each dry electrode acquisition circuit can cooperate to realize the electrode connection detection function, and the driving circuit 7 can detect whether each dry electrode is in good contact with the human body. The electrode connection detection function can be used to check whether each dry electrode is in good contact with the human body to avoid affecting the detection effect due to poor contact. In addition, the driving circuit 7 can also suppress common mode interference. Specifically:

[0074] The connectivity detection function is implemented as follows: the high-precision ADC outputs a specific current or voltage signal from the Biasout port through the internal bias drive amplifier, and the signal is injected into the drive dry electrode 8 through the drive circuit 7. The drive dry electrode 8 can be connected to the mastoid, earlobe, top of the head or forehead of the human body. After the signal enters the human body, the signal returned by each detection integrated dry electrode is monitored. If the integrated dry electrode 1 is well connected to the skin, a stable signal will be detected; if the connection is disconnected or the contact is poor, the signal will change.

[0075] In other words, a specific current or voltage is transmitted to the human body through the driving circuit 7. If the collection dry electrode 11 is well connected to the human body, the specific current or voltage can be transmitted to each collection dry electrode 11 through the human body and then collected by the ADC. If the connection is not good, the specific current or voltage cannot be transmitted back. In theory, the driving dry electrode 8 should be appropriately away from the area of ​​the collection dry electrode 11; in actual application, the position can be adjusted according to the actual situation.

[0076] On the other hand, since the driving circuit 7 is connected to the built-in bias driving amplifier of the high-precision ADC, a voltage signal can be sent to the user's body surface to suppress common-mode interference. Figure 6 As an optional configuration, by configuring the internal register 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 being compared with the internal reference voltage, they are fed back to the output terminal in an inverted manner to generate a voltage with the opposite polarity to the interference signal, which is injected into the subject's body, thereby offsetting the common-mode interference of each channel and the human body coupling and improving the common-mode rejection ratio of the system.

[0077] 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 prevent damage to the chip caused by an external short circuit or to prevent damage to the human body caused by a large current generated by a chip failure. Figure 7 As shown, preferably TVS tubes D1 and D2 may be 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).

[0078] In summary, the high-precision portable multi-channel bioelectric acquisition system based on dry electrodes provided in the embodiments of the present application includes:

[0079] Several integrated dry electrode modules arranged in various parts of the human body are used to receive bioelectric signals from the human body; the bioelectric signals are mainly brain waves and / or eye waves;

[0080] The signal transmission feeder 2 connects the integrated dry electrodes 1 worn at various locations on the human body and the analog channels 3 in the circuit system, and is used to transmit the bioelectrical signals from the integrated dry electrodes 1 at various locations to the analog channels 3;

[0081] Analog channel 3, used to amplify and / or filter each bioelectric signal;

[0082] A multi-channel high-precision analog-to-digital converter (ADC) 4 is used to synchronously and accurately collect the analog signals output by the analog channel 3 and convert the analog signals into digital signals that are easy to process; the analog-to-digital converter is controlled by a subsequent microprocessor 5;

[0083] 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.

[0084] 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 .

[0085] The portable multi-channel bioelectric acquisition system based on dry electrodes provided in the embodiment of the present application solves the signal accuracy problem of the portable bioelectric acquisition device through multiple components:

[0086] (1) Since the impedance between the dry electrode and the human body is relatively large, it is easy to cause a poor signal-to-noise ratio. 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 used to enhance the signal-to-noise ratio and improve the load capacity.

[0087] (2) Use a feeder with a shielding layer to shield electromagnetic interference in the environment and the crosstalk of signals between leads to reduce noise.

[0088] (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, thereby improving measurement accuracy.

[0089] (4) Filters can be used to remove unnecessary out-of-band noise and improve the signal-to-noise ratio.

[0090] (5) By setting up the driving circuit 7, the electrode connection 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.

[0091] (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.

[0092] 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.

[0093] Preferably, the ADC uses a high-precision ADC dedicated to bioelectricity, such as ADS1299, ADSD1299 and other chips. This chip has the advantages of low noise, high common mode rejection ratio, multi-channel synchronous sampling and low power consumption.

[0094] According to the needs of practical applications, multiple ADCs can also 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 cascaded, the cascade method is as follows: Fig. 9 As shown. A programmable amplifier (PGA) is integrated inside the ADC, which 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, which can controllably low-pass filter the input signal to prevent the occurrence of spectrum aliasing.

[0095] In addition, based on the hardware architecture provided by the present application, the sampling frequency of the ADC in the present system can be controlled by the microprocessor 5. When collecting high-frequency bioelectric signals or 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 external devices do not require real-time performance, a slower frequency can be sampled for analog-to-digital conversion to reduce redundant data, thereby achieving better time accuracy.

[0096] Through the various components set in the above multi-channel bioelectric 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 bioelectric acquisition system is realized. The circuit system schematic diagram can be found in Fig.10 .

[0097] The portable multi-channel bioelectric acquisition system based on dry electrodes provided in the embodiment of the present application has high system integration and low power consumption, so that the bioelectric acquisition device has better signal amplitude accuracy and time accuracy while taking into account portability, comfort and convenience. It is conducive to the long-term wearing of the subject and the accurate detection of bioelectric signals, improves the accuracy of brain-computer interface and neural diagnosis and analysis, and reduces the possibility of misjudgment and misdiagnosis.

[0098] 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 the leads, 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; using 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 bioelectric signal collected by the dry electrode is improved, the quality and accuracy of the collected signal are guaranteed, and together high-precision collection of the bioelectric signal is achieved, thereby achieving the purpose of improving the precision and accuracy of the bioelectric collection system.

[0099] At the same time, the added drive circuit can realize the electrode connectivity detection function, allowing real-time monitoring of the contact status between each dry electrode and the human body, ensuring 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 occur. The integrated drive circuit can also effectively suppress baseline drift, stabilize the bioelectric signal near a relatively constant baseline, and effectively reduce multi-channel common-mode interference;

[0100] 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.

[0101] In summary, this solution effectively overcomes the problem of dry electrode signal accuracy 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.

[0102] 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, which are used to fit the key positions of the human body and capture and conduct bioelectric signals from various parts of the human body; transmission feeders with shielding layers, which are used to conduct the bioelectric signals captured by the dry electrodes to the analog channel; the instrument amplifier in the analog channel uses the signal to accurately amplify the signal; the 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, which is used to collect the bioelectric signals of the multi-channel into digital signals with high precision; a controller is connected to the high-precision analog-to-digital converter, which is used to receive digital signals and process the signals; a wireless communication module is connected to the controller, which is used to send the collected signals to a remote device (processor, computer or cloud platform). The system can realize 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.

[0103] 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 convenience of the equipment, it solves the signal accuracy problem of current dry electrode portable biopotential acquisition equipment.

[0104] In one embodiment, Fig.11 As shown, a control method for a portable multi-channel bioelectric acquisition system is provided, and the method is applied to the portable multi-channel bioelectric acquisition system based on dry electrodes provided in the above embodiment as an example for description, and includes the following steps:

[0105] S1, detecting through a driving circuit whether each integrated dry electrode is tightly connected to each part of the human body to be collected;

[0106] 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;

[0107] That is to say, if it is found that some dry electrodes are not tightly connected to the human body, a signal can be sent through the microprocessor to prompt the user to adjust the wearing;

[0108] S3, if it is detected that they are all tightly connected, the microprocessor receives the control signal sent by the external device, sends the first control command and / or the second control command to the multi-channel high-precision analog-to-digital converter, adjusts the amplification gain and / or the sampling frequency of the multi-channel high-precision analog-to-digital converter, and enables the portable multi-channel bioelectric acquisition system to acquire bioelectric signals at the target amplification gain and / or the target sampling frequency;

[0109] S4, the microprocessor receives the bioelectric signals collected by each integrated dry electrode and performs calculation processing on the collected bioelectric signals;

[0110] S5, the microprocessor sends the calculation result to the external device.

[0111] In brief, the method involves:

[0112] Check whether each dry electrode is tightly connected to the human body;

[0113] Receive control instructions from external devices;

[0114] Use appropriate amplification and sampling rate to collect bioelectric signals;

[0115] Perform certain calculations on the collected bioelectric digital signals;

[0116] Transfer it to an external device.

[0117] 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. Moreover, 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 execution order of these steps or stages is not necessarily sequential, but can be performed in turn or alternately with other steps or at least part of the steps or stages in other steps.

[0118] The technical features of the above embodiments may be combined arbitrarily. 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 bioelectric acquisition system based on dry electrodes, characterized in that: include: A plurality of integrated dry electrodes are respectively arranged at a plurality of parts of the human body to be collected; each integrated dry electrode comprises a collection dry electrode and a follower circuit, the collection dry electrode is used to collect the bioelectrical signal of 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 line is electrically connected to the multi-channel data output terminals of the multiple follower circuits; the signal transmission feeder line has a shielding layer; An analog channel, whose multi-channel data input terminal is electrically connected to the signal transmission feeder; A multi-channel high-precision analog-to-digital converter, whose 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 bioelectric 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 bioelectric acquisition system based on dry electrodes according to claim 1 is characterized in that: The follower circuit includes an operational amplifier U1, a non-inverting input pin of the operational amplifier U1 is electrically connected to the data output terminal of the corresponding acquisition dry electrode, and an inverting input pin and an output pin of the operational amplifier U1 are electrically connected to the signal transmission feeder through a resistor R.

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

5. The high-precision portable multi-channel bioelectric acquisition system based on dry electrodes according to claim 1 is 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 bioelectric acquisition system based on dry electrodes according to claim 1 is characterized in that: 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.

7. The high-precision portable multi-channel bioelectric acquisition system based on dry electrodes according to claim 1 is 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 a 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 bioelectric acquisition system based on dry electrodes according to claim 7 is 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 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 bioelectric 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. 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 capacitor C1 and the resistor R1 in parallel. 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 human skin.

10. A control method for a high-precision portable multi-channel bioelectric acquisition system, characterized in that: The high-precision portable multi-channel bioelectric acquisition system based on dry electrodes as described in claim 9, the method comprising: The driving circuit is used to detect whether each integrated dry electrode is tightly connected to each part of the human body to be collected; 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; If it is detected that they are all tightly connected, the microprocessor receives a control signal from an external device, sends a first control command and / or a second control command to the multi-channel high-precision analog-to-digital converter, adjusts the amplification gain and / or sampling frequency of the multi-channel high-precision analog-to-digital converter, and enables the portable multi-channel bioelectric acquisition system to acquire bioelectric signals at a target amplification gain and / or a target sampling frequency; The microprocessor receives the bioelectric signals collected by each integrated dry electrode and performs calculation processing on the collected bioelectric signals; The microprocessor sends the calculation results to the external device.

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