Study And Implementation On Real-time Brain-Computer Interface System Based On Visual Evoked Potential

Brain-computer interface (BCI) is an EEG-based communication and control system between human and computer or other electric devices, which does not depend on the brain's normal output channels of peripheral nerves and muscles. It's a novel kinds of human interface. An important use of equipment based on BCI is providing a communication and control channel for subjects with severe neuromuscular dysfunction to manage external events. BCI has great significance in rehabilitation and other fields.There are many research methods of BCI., the EEG can be used in BCI including VEP,ERS/ERD,SCP and spontaneous EEG etc. Visual Evoked Potential (VEP) is the evoked response elicited by the specific visual stimulate, which occur at specific time and specific location, is relatively easy to be detected and recognized. This paper studies on the BCI system based on VEP.This paper has studied and implemented a real-time BCI system based on VEP, the study includes: design and implementation of visual stimulator,the real-time signal transmission between stimulation and acquisition procedure,extraction and identification of VEP,the integration of the whole real-time system and experiments on this system.The visual stimulator has been implemented: selects colors,frequencies,cycle and other important parameters which can easily invoke VEP; add modules which real-time processing needs, including: signal processing,results feedback and synchronous control etc. Much experiment have been done.One of the key problems needs to be solved is the real-time data transmission among programs between the signal collection and stimulation program. This paper proposes DLL to realize shared memory technology based on file mapping. The result of experiments shows that this method is a good solution.SSVEP and TVEP have been studied and implemented respectively, corresponding methods is cumulative average and correlation coefficient,FFT.To integrate the whole system, to solve comunication and control proplems among different environments(VC, DLL, Labview), the real-time signal transmission technology and the global variable technology of LabVIEW have been used.