Two dimensional convolution.
C = CONV2(A, B) performs the 2-D convolution of matrices
A and B. If [ma,na] = size(A) and [mb,nb] = size(B), then
size(C) = [ma+mb-1,na+nb-1].
C = CONV2(A,B,'shape') returns a subsection of the 2-D
convolution with size specified by 'shape':
'full' - (default) returns the full 2-D convolution,
'same' - returns the central part of the convolution
that is the same size as A.
'valid' - returns only those parts of the convolution
that are computed without the zero-padded
edges, size(C) = [ma-mb+1,na-nb+1] when
size(A) > size(B).
CONV2 is fastest when size(A) > size(B).
See also XCORR2, CONV , XCORR, DECONV , FILTER2 .