Research Article

Wavelet-Based Semblance Methods to Enhance the Single-Trial Detection of Event-Related Potentials for a BCI Spelling System

Algorithm 2

Semblance-based ERP window selection by channels (SEWS-1).
(1)Input: given the EEG signal matrix X, with C channels and T temporal samples
(2)Output: the bounds of the temporal window and for each C channel
(3)Set the window threshold ,
(4)for to C do
(5) Compute the average of responses belonging to the target class for channel c
(6) Compute the average of responses belonging to the nontarget class for channel c
(7) Compute the and using equation (2)
(8) Compute the semblance using equation (4)
(9) Compute the dot product D using equation (5)
(10) Compute the standard deviation of D over the scales and standardise it between 0 and 1
(11) The limit is given by the first t from the left which meets
(12) The limit is given by the first t from the right which meets
(13)end for