Steady-State Visual Evoked Potential based Brain controlled wheelchair system

Brain controlled wheelchair system is a Brain-computer interface (BCI) allowing people with severe neuromuscular disorder to control the navigation by themselves. Indeed, it replaces muscular activities by neurophysiological ones. The advantages of the Steady State Visual Evoked Potential (SSVEP) make it a favorable choice to be used in the BCI. The aim of the present study is to design a brain controlled wheelchair system which is cheap and easy to use. Two signal processing methods for SSVEP frequencies detection are presented and discussed. The first method is based on the calculation of the normalized amplitude spectrum. The second method is based on the comparison between the signals´ signal to noise ratio calculated on specific frequencies. A comparison of the accuracy of these methods with a frequency resolution of 0.1Hz allows the identification of the most precise method among them both. Results show that by using the second method, the system can reach for 97% of the four directions´ navigation´s accuracy.