Calculates spatial filter matrix for Laplacian derivations.
Returns a spatial filter matrix used to calculate Laplacian derivations as
well as indices used to plot in a topographical layout.
Assuming that the data vector s is of dimension <samples x channels>, the
Laplacian derivation s_lap can then be calculated by s_lap = s * lap.
Usage:
[lap, plot_index, n_rows, n_cols] = getMontage(montage);
Input parameters:
montage ... Electrode montage, either a predefined string (currently,
'16ch', '22ch', '28ch' and '60ch' are available) or a matrix
containing ones where the electrodes are located and zeros
elsewhere
Output parameters:
lap ... Laplacian filter matrix
plot_index ... Indices for plotting the montage
n_rows ... Number of rows of the montage
n_cols ... Number of columns of the montage