Different Duty Cycle Ratio and Brightness Of Visual Stimuli Change To Steady State Visual Evoked Potential Response

Year 2016, , 82 - 85, 01.12.2016

Zeki Oralhan , Mahmut Tokmakçı

https://doi.org/10.18100/ijamec.266073

Abstract

Stimuli types are
very crucial for the performance of electroencephalogram (EEG) based brain
computer interface (BCI) systems. This study aims to investigate methods for
obtaining higher information transfer rate (ITR) through duty cycle and
brightness variation of visual stimuli which have high frequency for steady
state visual evoked potential-based BCI. Although previous studies were
concentrated on either duty cycle or brightness of stimuli separately, our
study focused on the change of duty cycle ratio and brightness of stimuli at
the same time. Duty cycle values of 40%, 50%, and 60% were used. During the
experiment, 16 flickering stimuli were used on liquid crystal display. Participants
gazed to the flicker which had frequency of 15 Hz. Canonical correlation
analyses (CCA) was used for channel selection and frequency detection.
According to the CCA, the maximum average accuracy of the experiment was 92.54%
when the frequency of flicker was in beta band and its duty cycle was 40% with
a brightness tuning wave. Under the same conditions stated above, average ITR
was improved 16.1% according to the most commonly used flicker model which is
square wave and has 50% duty cycle.

Keywords

Brain Computer Interface, EEG, Human-Computer Interaction and Systems, Steady State Visual Evoked Potential

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