Brain Controlled Car
Extraction of SSVEP Signals of a Capacitive EEG Helmet for Human Machine Interface
Abstract— The use of capacitive electrodes for measuring EEG eliminates the preparation procedure known from classical noninvasive EEG measurements. The insulated interface to the brain signals in combination with steady-state visual evoked potentials (SSVEP) enables a zero prep human machine interface triggered by brain signals. This paper presents a 28channel EEG helmet system based on our capacitive electrodes measuring and analyzing SSVEPs even through scalp hair. Correlation analysis is employed to extract the stimulation frequency of the EEG signal. The system is characterized corresponding to the available detection time with different subjects. As demonstration of the use of capacitive electrodes for SSVEP measurements, preliminary online Brain-Computer Interface (BCI) results of the system are presented. Detection times lie about a factor of 3 higher than in galvanic EEG SSVEP measurements, but are low enough to establish a proper communication channel for Human Machine Interface (HMI).
helmet based design. This provides a direct access to EEG signals even through scalp hair. Visual stimulation of the brain causes visual evoked potentials (VEPs), which can be measured in the region of the visual cortex [7]. If the stimulation repetition frequency increases above 6 Hz, the VEPs come to a steady state, called steady-state visual evoked potentials (SSVEP). These SSVEP can easily be recorded with the EEG and are suitable for a communication interface in a BCI application. Several SSVEP-BCI systems have been demonstrated by now [8], [9], [10]. Stimulation is often done by LED or flickering areas on a PC screen as separated areas or checkerboards. The signal processing is generally done by power spectral density analysis or correlation analysis [11]. II. SENSORS & SYSTEM A. Sensor The capacitive coupling between the body and our sensor is based on a metallic electrode plate
Abstract— The use of capacitive electrodes for measuring EEG eliminates the preparation procedure known from classical noninvasive EEG measurements. The insulated interface to the brain signals in combination with steady-state visual evoked potentials (SSVEP) enables a zero prep human machine interface triggered by brain signals. This paper presents a 28channel EEG helmet system based on our capacitive electrodes measuring and analyzing SSVEPs even through scalp hair. Correlation analysis is employed to extract the stimulation frequency of the EEG signal. The system is characterized corresponding to the available detection time with different subjects. As demonstration of the use of capacitive electrodes for SSVEP measurements, preliminary online Brain-Computer Interface (BCI) results of the system are presented. Detection times lie about a factor of 3 higher than in galvanic EEG SSVEP measurements, but are low enough to establish a proper communication channel for Human Machine Interface (HMI).
helmet based design. This provides a direct access to EEG signals even through scalp hair. Visual stimulation of the brain causes visual evoked potentials (VEPs), which can be measured in the region of the visual cortex [7]. If the stimulation repetition frequency increases above 6 Hz, the VEPs come to a steady state, called steady-state visual evoked potentials (SSVEP). These SSVEP can easily be recorded with the EEG and are suitable for a communication interface in a BCI application. Several SSVEP-BCI systems have been demonstrated by now [8], [9], [10]. Stimulation is often done by LED or flickering areas on a PC screen as separated areas or checkerboards. The signal processing is generally done by power spectral density analysis or correlation analysis [11]. II. SENSORS & SYSTEM A. Sensor The capacitive coupling between the body and our sensor is based on a metallic electrode plate