A Chinese Text Input Brain–Computer Interface Based on the P300 Speller

Abstract

A visual speller is a brain-computer interface that empowers users with limited motor functionality to input text into a computer by measuring their electroencephalographic responses to visual stimuli. Most prior research on visual spellers has focused on input of alphabetic text. Adapting a speller for other types of segmental or syllabic script is straightforward because such scripts comprise sufficiently few characters that they may all be displayed to the user simultaneously. Logographic scripts, such as Chinese hanzi, however, impose a challenge: How should the thousands of Chinese characters be displayed to the user? Here, we present a visual speller, based on Farwell and Donchin's P300 Speller, for Chinese character input. The speller uses a novel shape-based method called the First-Last, or FLAST, method to encode more than 7,000 Chinese characters. Characters are input by selecting two components, from a set of 56 distinct components, that match the shape of the target character, followed by selection of the character itself. At the input speed of one character per 107 s, 24 able-bodied participants achieved mean online accuracy of 82.8% per component selection and 63.5% per character input. At the faster input speed of one character per 77 s, mean online accuracy was 59.4% per component selection and 33.3% per character input.

Effects of Luminosity Contrast and Stimulus Duration on User Performance and Preference in a P300-Based Brain–Computer Interface

“…The P300 Speller, developed by Farewell and Donchin (1988), presents end users with a character matrix or syllabic script (Minett et al, 2012) composed of different characters classified as target and nontarget. The matrix's rows and columns are randomly intensified (i.e., made brighter), creating visual stimuli.…”

Binary DE-Based Channel Selection and Weighted Ensemble of SVM Classification for Novel Brain–Computer Interface Using Devanagari Script-Based P300 Speller Paradigm

“…Although most of the P300 speller paradigms are developed for English language, P300 BCI with other alphabets, such as alphabets in Chinese (Jin et al, 2010;Minett et al, 2012) , Japanese (Yamamoto, Yoshikawa, & Furuhashi, 2015) and Arabic languages (Kabbara, Hassan, Khalil, Eid, & El-Falou, 2015) have also been published. A practical BCI system should be able to produce accurate results with high ITR.…”

The Role of the Interplay between Stimulus Type and Timing in Explaining BCI-Illiteracy for Visual P300-Based Brain-Computer Interfaces

“…This feature makes the paradigm eligible not only for standard alphanumeric spelling; since the seminal work of Farwell and Donchin ( 1988 ) many different applications have been proposed. The feasibility of using non-character matrices of stimuli has been confirmed in studies involving healthy as well as disabled subjects spelling with different alphabets like hiragana (Ikegami et al, 2014 ) or logograms, i.e., Chinese alphabet (Minett et al, 2012 ); operating both virtual and real smart-home environments (Bayliss, 2003 ; Holzner et al, 2009 ; Carabalona et al, 2012 ) or browsing the Internet (Mugler et al, 2010 ).…”