Table 2.

Symbols and notations.

Symbol	Description
Nt	Number of trials
Nc	Number of channels
Ns	Number of samples
Ei	EEG data matrix of a single trial, $E_i\in {ℝ}^{N_c\times N_s}$
Ci	Covariance of Ei, $C_i\in {ℝ}^{N_c\times N_c}$
W	Spatial filter matrix, $W\in {ℝ}^{N_c\times L},L\le N_c$
wi	A spatial filter vector, $w_i\in {ℝ}^{N_c},W=\left[w_1,w_2,\cdots ,w_L\right]$