Wearable Eeg Acquisition System For Motion Artifact Correction

EEG is a method of measuring brain activity through small voltage changes collected by electrodes on the human scalp,and EEG measurements can indirectly reflect the cognitive function of the brain or diagnose neurological diseases,such as in hearing.In the evoked stimulation experiment,the corresponding stimulation components will appear in the EEG signal of the subjects after receiving the auditory stimulation.However,in the process of this type of experiment,the subjects are often required to remain still to obtain better experimental results.Because the EEG measurement in motion state will introduce a large number of motion artifacts(Motion Artifact,MA),resulting in the degradation of EEG signal quality,and the current understanding of motion artifact is mainly limited to the baseline drift and the contact interface between the electrode and the skin.The impedance of its equivalent circuit changes.In order to further improve the quality of the EEG signal and the experimental effect in the state of motion,this thesis adopts the bipolar lead technology to collect the EEG signal,and designs an EEG acquisition system that can suppress the motion artifacts based on the adaptive filtering algorithm.In this thesis,an EEG acquisition system with motion artifact correction function is designed.The system can perform auditory steady-state evoked and event-related potential experiments in motion scenarios,and realize Wi-Fi transmission,display and storage the EEG signals.First of all,the analog front-end amplifier circuit of this system adopts bipolar lead technology to realize EEG acquisition.Secondly,based on CC3200 main control chip and TIRTOS real-time operating system,the synchronous transmission of EEG and acceleration sensor signals is realized,and a stable network connection is established with the computer.Finally,the computer terminal uses the acceleration sensor signal as a reference signal to perform adaptive filtering based on the minimum mean square error to characterize the change of motion artifact,thereby realizing the correction of motion artifact in the EEG signal.In addition,this thesis also realizes the synchronous transmission of event tags and EEG signals based on the QT software design.In order to further ensure the validity and reliability of the EEG signal collected by this system,this thesis refers to the national standard JJG-1043 for digital EEG,and conducts electrical performance tests such as input noise and common mode rejection ratio for the motion artifact correction system.The test results Compliance with the standard proves the effectiveness of the system function.On this basis,the eye-closed ?-wave rhythm experiment and the auditory steady-state evoked potential experiment were designed according to the literature research.The experimental results are in full compliance with the literature references,which proves the reliability of the system function.Finally,this thesis designs the verification experiments of auditory event-related potentials and head movements under the motion state,and conducts statistical analysis on the P300 data of 8 subjects.The results show that the EEG acquisition system designed in this thesis can correct the motion artifacts.