Brain-computer interface (BCI) is a communication channel which does not depend on the brain’s normal output pathways of peripheral nerves and muscles. It helps the paralyzed patients communicate with the environment and improve life quality. The electroencephalogram(EEG) based BCI is the main interest of current BCI research due to its advantages of low cost, easy operation and non-invasiveness. The study of BCI involves three questions: signal collection, signal processing and analysis, and external contr...