EEG-based hybrid QWERTY mental speller with high information transfer rate

Author(s):  
Er. Akshay Katyal ◽  
Rajesh Singla
2018 ◽  
Vol 28 (10) ◽  
pp. 1850034 ◽  
Author(s):  
Wei Li ◽  
Mengfan Li ◽  
Huihui Zhou ◽  
Genshe Chen ◽  
Jing Jin ◽  
...  

Increasing command generation rate of an event-related potential-based brain-robot system is challenging, because of limited information transfer rate of a brain-computer interface system. To improve the rate, we propose a dual stimuli approach that is flashing a robot image and is scanning another robot image simultaneously. Two kinds of event-related potentials, N200 and P300 potentials, evoked in this dual stimuli condition are decoded by a convolutional neural network. Compared with the traditional approaches, this proposed approach significantly improves the online information transfer rate from 23.0 or 17.8 to 39.1 bits/min at an accuracy of 91.7%. These results suggest that combining multiple types of stimuli to evoke distinguishable ERPs might be a promising direction to improve the command generation rate in the brain-computer interface.


2013 ◽  
Author(s):  
Zacharias Vamvakousis ◽  
Rafael Ramirez

P300-based brain-computer interfaces (BCIs) are especially useful for people with illnesses, which prevent them from communicating in a normal way (e.g. brain or spinal cord injury). However, most of the existing P300-based BCI systems use visual stimulation which may not be suitable for patients with sight deterioration (e.g. patients suffering from amyotrophic lateral sclerosis). Moreover, P300-based BCI systems rely on expensive equipment, which greatly limits their use outside the clinical environment. Therefore, we propose a multi-class BCI system based solely on auditory stimuli, which makes use of low-cost EEG technology. We explored different combinations of timbre, pitch and spatial auditory stimuli (TimPiSp: timbre-pitch-spatial, TimSp: timbre-spatial, and Timb: timbre-only) and three inter-stimulus intervals (150ms, 175ms and 300ms), and evaluated our system by conducting an oddball task on 7 healthy subjects. This is the first study in which these 3 auditory cues are compared. After averaging several repetitions in the 175ms inter-stimulus interval, we obtained average selection accuracies of 97.14%, 91.43%, and 88.57% for modalities TimPiSp, TimSp, and Timb, respectively. Best subject’s accuracy was 100% in all modalities and inter-stimulus intervals. Average information transfer rate for the 150ms inter-stimulus interval in the TimPiSp modality was 14.85 bits/min. Best subject’s information transfer rate was 39.96 bits/min for 175ms Timbre condition. Based on the TimPiSp modality, an auditory P300 speller was implemented and evaluated by asking users to type a 12-characters-long phrase. Six out of 7 users completed the task. The average spelling speed was 0.56 chars/min and best subject’s performance was 0.84 chars/min. The obtained results show that the proposed auditory BCI is successful with healthy subjects and may constitute the basis for future implementations of more practical and affordable auditory P300-based BCI systems.


2020 ◽  
Vol 32 (01) ◽  
pp. 2050003
Author(s):  
Akshay Katyal ◽  
Rajesh Singla

Hybrid brain–computer interfacing (BCI), recently, has been the epicenter of research in the area of rehabilitation engineering. The concept is based on the principle that the paradigm used for the BCI elicits one BCI marker in combination with one or more BCI modalities or other physiological signals. These paradigms elicit human brain response to successfully determine user intentions. Steady-state visually evoked potential (SSVEP) has been the favourite amongst researchers to combine with other BCI modalities such as P300, Motor Imagery (MI), etc. to develop assistive devices (ADs) based on hybrid BCI. This research paper is a record of a comparative study conducted between two hybrid BCI’s, namely hybrid BCI-1, hybrid BCI-2 and traditional SSVEP BCI. Both hybrid paradigms are similar in schematics but differ in the operational protocol. The study aimed to find the optimal protocol which greatly enhances the average information transfer rate (ITR) of a BCI-based AD. Hybrid BCI-1 showed lower classification accuracy (90.36%) and higher false activation rate (FAR) (3.16%) as compared to Hybrid BCI-2 (92.35% and 2.78%, respectively) as well as traditional SSVEP (93.38% and 2.73%, respectively). However, the average ITR of Hybrid BCI-1 (80.76 bits/min) was much higher than that of Hybrid BCI-2 (41.21 bits/min) and traditional SSVEP paradigm (36.34 bits/min). This led to the conclusion, that Hybrid BCI-1 is the most viable option for developing an AD.


Author(s):  
Kun Chen ◽  
Fei Xu ◽  
Quan Liu ◽  
Haojie Liu ◽  
Yang Zhang ◽  
...  

Among different brain–computer interfaces (BCIs), the steady-state visual evoked potential (SSVEP)-based BCI has been widely used because of its higher signal to noise ratio (SNR) and greater information transfer rate (ITR). In this paper, a method based on multiple signal classification (MUSIC) was proposed for multidimensional SSVEP signal processing. Both fundamental and second harmonics of SSVEPs were employed for the final target recognition. The experimental results proved it has the advantage of reducing recognition time. Also, the relation between the duty-cycle of the stimulus signals and the amplitude of the second harmonics of SSVEPs was discussed via experiments. In order to verify the feasibility of proposed methods, a two-layer spelling system was designed. Different subjects including those who have never used BCIs before used the system fluently in an unshielded environment.


2015 ◽  
Vol 738-739 ◽  
pp. 594-597
Author(s):  
Ming Liu ◽  
Huan Zhang ◽  
Ding Jun Hu

Light Communication is one of the most common means of vessel communication, with merits of simple, easy-to-use, resistance to electromagnetic interference and so on. Compared with other means of vessel communication, the shortcomings of traditional lighting communication are highlighted, for example, it requires specialized training soldiers, and the information transfer rate is too low. In this paper, an automatic light receiver is presented, and an improved image segmentation algorithm in automatic light communication system is investigated. In the end, some conclusions are given to show the effectiveness of automatic light communication system and its particular application for military use.


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