A novel steady-state visually evoked potential-based brain-computer interface design: Character Plotter

In this paper, an electroencephalogram-based innovative brain-computer interface (BCI), known as "Character Plotter", is presented. The proposed design uses steady-state visually evoked potentials. The subjects generate characters by drawing, step by step, lines between six circles on the computer screen. Additionally, there are three circles for controlling the drawing procedure. The features obtained from canonical correlation analysis are used for classification. The proposed synchronous BCI design was tested on 16 subjects in offline and online experimental tasks using support vector machines, linear discriminant analysis and the nearest mean classifier. The obtained classification performances indicate that the proposed design can be successfully used in classification. The Character Plotter converges to the natural writing scheme of humans. Therefore, subjects can adapt to the BCI design in a short training session.