Brain Computer Interface
1.INTRODUCTION
What is a Brain-Computer Interface?
A brain-computer interface uses electrophysiological signals to control remote devices. Most current BCIs are not invasive. They consist of electrodes applied to the scalp of an individual or worn in an electrode cap such as the one shown in 1-1 (Left). These electrodes pick up the brain’s electrical activity (at the microvolt level) and carry it into amplifiers such as the ones shown in 1-1 (Right). These amplifiers amplify the signal approximately ten thousand times and then pass the signal via an analog to digital converter to a computer for processing. The computer processes the
EEG signal and uses it in order to accomplish tasks such as communication and environmental control. BCIs are slow in comparison with normal human actions, because of the complexity and noisiness of the signals used, as well as the time necessary to complete recognition and signal processing.
The phrase brain-computer interface (BCI) when taken literally means to interface an individual’s electrophysiological signals with a computer. A true BCI only uses signals from the brain and as such must treat eye and muscle movements as artifacts or noise. On the other hand, a system that uses eye, muscle, or other body potentials mixed with EEG signals, is a brain-body actuated system.
Figure : Scheme of an EEG-based Brain Computer Interface with on-line feedback. The EEG is recorded from the head surface, signal processing techniques are used to extract features. These features are classified, the output is displayed on a computer screen. This feedback should help the subject to control its EEG patterns.
The BCI system uses oscillatory electroencephalogram (EEG) signals, recorded during specific mental activity, as input and provides a control option by its output. The obtained output signals are presently evaluated for different purposes, such as cursor control, selection of letters or words, or control of prosthesis.
What is a Brain-Computer Interface?
A brain-computer interface uses electrophysiological signals to control remote devices. Most current BCIs are not invasive. They consist of electrodes applied to the scalp of an individual or worn in an electrode cap such as the one shown in 1-1 (Left). These electrodes pick up the brain’s electrical activity (at the microvolt level) and carry it into amplifiers such as the ones shown in 1-1 (Right). These amplifiers amplify the signal approximately ten thousand times and then pass the signal via an analog to digital converter to a computer for processing. The computer processes the
EEG signal and uses it in order to accomplish tasks such as communication and environmental control. BCIs are slow in comparison with normal human actions, because of the complexity and noisiness of the signals used, as well as the time necessary to complete recognition and signal processing.
The phrase brain-computer interface (BCI) when taken literally means to interface an individual’s electrophysiological signals with a computer. A true BCI only uses signals from the brain and as such must treat eye and muscle movements as artifacts or noise. On the other hand, a system that uses eye, muscle, or other body potentials mixed with EEG signals, is a brain-body actuated system.
Figure : Scheme of an EEG-based Brain Computer Interface with on-line feedback. The EEG is recorded from the head surface, signal processing techniques are used to extract features. These features are classified, the output is displayed on a computer screen. This feedback should help the subject to control its EEG patterns.
The BCI system uses oscillatory electroencephalogram (EEG) signals, recorded during specific mental activity, as input and provides a control option by its output. The obtained output signals are presently evaluated for different purposes, such as cursor control, selection of letters or words, or control of prosthesis.