A Brain Computer Interface (BCI) system is a communication system where a person has the ability to communicate with a computer through his or her brain signals rather than using the peripheral nerves and muscles. A BCI system effectively allows for the conversion of patterns of electrical brain activity into commands to control specific equipment. BCI technology relies on the acquisition of electrical signals generated by billions of neurons inside the brain. The electrical fluctuations that arise from these neurons reach the scalp where they can be detected and recorded by means of non-invasive metal electrodes through a process known as electroencephalography (EEG). In a BCI system EEG data is recorded from the human subject and this is then processed to extract reliable features which can then be mapped into computer based commands such as moving a cursor on a screen or selecting from sets of letters.
There are various neurophysiological phenomena evoking distinctive characteristics in brain signals that are suitable as control signals for BCI systems such as, sensorimotor rhythms, visual evoked potentials and P300 evoked potentials. The department has focused on the development of EEG signal analysis and processing techniques to extract reliable features for the classification of different mental states. Studies have mainly focused on the development of innovative algorithms for the segmentation of sleep EEG data and to improve the performance of EEG-based BCIs.
We have developed a music player application based on steady-state visually evoked potentials (SSVEPs) which are electrical potentials evoked in the brain in response to repetitive visual stimulation. This response is exhibited as oscillatory neural activity at the frequency of the flickering stimulus and harmonics thereof, and is prominent in the occipital region of the brain. In the music player application various visual stimuli that induce SSVEPs at different frequencies are associated with distinct commands. A user activates a particular command by focusing on the targeted stimulus. A specific pattern of brain activity related to that stimulus is then automatically identified by the BCI and instantaneously translated into a signal to activate the corresponding music player command. The tests conducted demonstrated a good and reliable performance of the music player application operating in real-time.
This BCI serves as a platform to test different signal processing algorithms with the aim of developing a robust BCI system that can be used outside of the laboratory. Current work is also targeted towards the building of a framework which allows a better understanding of the process involved in the brain with the end goal of extracting more reliable features to enhance the information transfer rate in such systems.This research on BCI systems can lead to improved assisted living devices which can have significant benefits for individuals with restricted mobility. Furthermore, these systems can also be used by healthy users as they can provide a novel way of interacting with entertainment and gaming applications.
25 April 2017
The Department of Systems and Control Engineering and the Centre for Biomedical Cybernetics are seeking students who are interested in pursuing studies leading to an MSc in Engineering degree (mainly by research) on any of the topics detailed here.