Embedded ERP Synchronous Correction Acquisition System

Event Related Potentials(ERP)is a kind of evoked potential of brain electrical signal,which is a kind of brain electrical potential caused by external stimulation.Event-related potentials reflect the cognitive process of the human body to external stimuli,so they are also called cognitive potentials.The ERP signal mainly observes the waveform changes in the time domain.and the detection of the waveform in the time domain needs to accurately record the location of the stimulus signal to facilitate later data analysis.In recent years,however,the fact shows the performance limitations in Graphic Processing Unit(GPU)and Frames Per Second(FPS)of Linux and Windows,many ERP paradigms cannot meet the time-frequency microsecond requirements,including real-time response and multi-tasking operation.In order to solve this problem,this paper developed a set of stimulus acquisition and analysis software based on Linux and ARM and a correction system based on μ C/OS-III and ARM.Focusing on the hardware circuit of the correction module,this paper developed a set of software system related to event-related potentials on the embedded development board Nano PC-T4.The work of this system mainly includes the construction of a portable system based on the embedded development board Nano PC-T4,the development and transplantation of the stimulation interface and real-time analysis program based on QT,and the hardware design and driver development of correction module based on ARM.For the development and transplantation of QT stimulus analysis program based on the portable system of embedded development board Nano PC-T4,this paper developed and ported the QT stimulus analysis program,including the presentation of QT-based sound and image stimuli,data acquisition filtering drawing and real-time ERP analysis.For the hardware design and driver development of the correction module based on ARM,it includes the hardware circuit design based on STM32F103,and the error calculation and real-time correction based on μC/OS-III.For the embedded ERP synchronization correction system,this paper integrated the ERP system into the embedded development board through QT,to realize the signal conversion through the photoelectric conversion module and the sound conversion module.And it also needs to realize mark acquisition,visual display and synchronous output of sound stimulus error by using STM32 based on μC/OS-III.To achieve the above-mentioned embedded ERP synchronization correction system and the related experimental verification,the work below needs to be finished: ERP software development,ARM-based software transplantation,hardware circuit design and debugging,the design and implementation of ERP and pattern reversal visual evoked potential experiment,and the corresponding data processing and analysis.Finally,in order to test whether the system can work normally,this paper tested the calibration module and the data acquisition and analysis module of the system.The verification of the calibration circuit was carried out through visual and auditory ERP experiments on 15 subjects.The results shown that the P300 waveform amplitude was improved and the latency was advanced,indicating that the experimental results were in line with the expectations.For the verification of the whole system of this design,the accuracy of the whole system was proved by experimental data of 13 tests.Finally,the practicability of the system was verified by the pattern reversal visual evoked potential experiment.