Error in calculating covariance matrix for common spatial pattern

[compubaby]

Hello,

I'm using the BCI Competition IV 2a dataset. I want to use the common spatial pattern of the BioSig toolbox.

I'm working on 3 channels. I adjusted my dataset into 2 classes (One-vs-Rest scheme) & reshaped my data from 3 dimension matrix into 2 dimension matrix:
· Class1 (left motor imagery) = 54000x3 channels. (one channel per column)
· Class2 (right, foot, tongue) = 162000x3 channels


I tried to calculate the extended covariance matrix which is needed as input for the csp.m
>>ECM = covm(C1, C2, 'E');
but I get the following error:
Error using covm (line 93) X and Y must have the same number of observations (rows).

How to calculate the covariance matrix of unequal matrices?

any help please