On the performance comparison of using checkerboard and flash ball visual stimulators for SSVEP-based BCI system

Abstract

Searching for the visual stimulators that can reduce eye-fatigue and enhance the performance of the steady state visual evoked potential (SSVEP)-based brain computer interface (BCI) system is one of the challenging problem in BCI research. In this paper, we compare the multi-command selection performance of the two visual stimulators, i.e. the proposed flash ball and the conventional checkerboard patterns, on the liquid crystal display (LCD) screen. Each visual stimulator consists of 12 commands with different flickering frequencies. These visual stimulators are evaluated with four subjects. Fast Fourier transform FFT is used to simply extract the features of interest. The results show that, by employing the flash ball pattern, the average accuracy is 76.67% which is higher than 60% accuracy of the checkerboard pattern. © 2013 Springer-Verlag.