Hi William,
In order to zero-pad a 2D data i.e. matrix, padding should be in such a way that the row length is equal to r1+r2-1 and column length is equal to c1+c2-1 where r1 and r2 are the number of rows and c1 and c2 are the number of columns of the 1st and 2nd matrices respectively.
Use the below code for reference.
rng default;
x = rand(2);
y = rand(3);
c = conv2(x,y);
xpad = [x zeros(size(x,1),size(y,2)-1); zeros(size(y,1)-1,size(x,2)+size(y,2)-1)];
ypad = [y zeros(size(y,1),size(x,2)-1); zeros(size(x,1)-1,size(y,2)+size(x,2)-1)];
c1 = ifft2(fft2(xpad).*fft2(ypad));
