y=block_oper(x,a)

function y=block_oper(x,a)
%block/template operation

[m,n]=size(x);
[ma,na]=size(a);
y=zeros(m-ma-1,n-na-1);

for index_i=1:m-ma+1
    for index_j=1:n-na+1
        y(index_i,index_j)=sum(sum(x(index_i:index_i+ma-1,index_j:index_j+na-1).*a));
    end
end