Hi everyone,
I've a little question concerning the implementation of the CAR filter in the offline analysis tool. Concretely, the carFilt.m performs CAR filtering on the specified signal.
Code: Select all
spatfiltmatrix=-ones(num_chans);
for i=1:num_chans
spatfiltmatrix(i, i)=num_chans-1;
end
signalOut=double(signal)*spatfiltmatrix;
However, by the end of the computations. Shouldn't the variable signalOut be divided by the number of channels? I mean, according to "A Practical Guide to Brain Computer Interfacing with BCI", the sum of the signal from all the channels(divided by the number of channels H) is substracted from the specified signal(s_h). But the matrix multiplication produces (H)s_h'=(H-1)s_h-SumOfTheRestOfTheChannels.
What am I missing?
Daniel