What is P300 Speller

A P300 speller enables a user to communicate to a computer without any physical movements. In this chapter, a P300 speller system using Devanagari script (DS) is presented. The variation and large size of DS character set increase the problems for classification. To effectively tackle these problems, the application of binary particle swarm optimization (BPSO) has been proposed for channel selection. The algorithm was applied with three different objectives: to maximize the accuracy, to investigate the optimal trade-off between the numbers of channels and the accuracy, and to achieve the maximum accuracy while selecting fixed number of channels. A modification in BPSO algorithm has also been proposed to achieve the third objective. The dataset was acquired from 10 subjects. The mean accuracy of 93.46% was achieved with BPSO algorithm when maximizing the accuracy was the sole objective. Further, average accuracy of 90.62% was achieved while selecting an optimal subset of eight channels.