Research On Chinese Character Spelling System Based On Hybrid Brain-Computer Interface

Many people with physical disabilities have lost the ability to communicate with the outside world normally in their daily life,while brain-computer interface technology has established a communication channel between the human brain and external devices,which can convert EEG signals into character information,providing a new way for people with physical disabilities to communicate with the outside world.P300 and SSVEP are widely used in the application of brain-computer interface character spelling system,however it is mainly aimed at spelling of English characters and numbers,lacking Chinese character spelling applications.Moreover,the existing Chinese character spelling system has cumbersome operation,complex paradigm and poor spelling performance.For these problems,this paper proposes a Chinese character spelling system based on a hybrid brain-computer interface.The research work is mainly carried out from the following aspects:Firstly,a character spelling system based on feature fusion of hybrid EEG signals is proposed in this paper.A two-step region-evoked paradigm was designed in this system to induce both P300 and SSVEP simultaneously.The SWLDA algorithm and the CCA algorithm are used to process the P300 and SSVEP respectively,and the P300 feature and SSVEP feature are fused.Using the feature fusion decision-making mechanism for classification and recognition can effectively improve the spelling accuracy and stability of the system characters.Secondly,this paper proposes a character spelling system based on parallel input of mixed EEG signals.In this system,a single-step region-evoked paradigm was designed in this system to induce both P300 and SSVEP simultaneously.The output of the two sub-spelling systems P300 and SSVEP is used to form the two-dimensional coordinate information of the target character,and the fast character spelling based on the multi-target option is realized.Finally,a pinyin input method based on a binary language model is designed in this paper.A binary language model is constructed,realizing the function of converting Pinyin to Chinese characters.A two-mode Chinese character spelling system combining the pinyin input method with the character spelling system is realized.The results show that the Chinese character spelling system based on the hybrid brain-computer interface proposed in this paper can realize the rapid spelling of Chinese characters and effectively improve the spelling efficiency of Chinese characters used commonly.