Design And Implementation Of Telephone Dialing System Based On The Control Of EEG Signals

A Brain Computer Interface (BCI) translates the user's intention into machine commands and thereby controls external devices without depending on the brain's normal output pathways of peripheral nerves and muscles. Its ultimate goal is to allow people who loss some kind of athletic ability to operate auxiliary equipment, such as computer and voice synthesizer. According to the theory of Steady-state Visual Evoked Potential (SSVEP), a telephone dialing system based on the control of EEG signals is researched and designed in the paper. The main tasks include three aspects:hardware visual stimulator, software experimental platform and signal processing algorithms.(1) The design of LED visual stimulator is completed. According to the functional requirements and performance of the dialing system, the overall design scheme of the LED visual stimulator is presented. For example:the use of each chip, assembly and debugging of the stimulator, and the preparation of the control code. In the end, the scheme design is verified to be effective and stable by taking experiment and processing the experimental data.(2) In the VC++development environment, the software experimental platform is based on the control of EEG signals to extract the SSVEP signal. The system mainly includes four software modules:EEG signal acquisition module, signal processing module, feature extraction module, command sending module and so on. And the software experimental platform laid a foundation for the future laboratory studies based on SSVEP.(3) Two algorithms of signal extraction and frequency detection are studied. And the two algorithms are Power Spectral Density Analysis (PSDA) method which is used for single signal channel and Canonical Correlation Analysis (CCA) method for multi-channel. The robustness of SSVEP extraction and frequency detection are improved by analyzing the multi-channel signals collected at the same time. Experimental results indicate that subjects can control their intention better to make a phone call by using the CCA method.