multiple matrix manipulation with different size matrices

Hello

I have two matrices (A and B) and am trying to combine them so that I can have the final matrix C. A small example of what I'm after is below.

A = 1  1
    1  1

B =  4 3 2 6
     7 8 2 1 
     3 2 4 5 
     1 4 3 2

    Hence C = A(1,1)*sum[B(1,1),B(1,2),B(2,1),B(2,2)] etc  

giving  C = 22  11
            10  14

I figure that I am going to require a loop in order to do this but I am unsure on how to proceed.

Please note that the actual matrices I have to perform this task on will be (100*100) size. I have scaled the problem down for this example.

Any help would be greatly appreciated.

Thanks

[Oleg Komarov]

Do you have the Image Processiong TB?

[Jennifer]

Not that I am aware of.

Answer 1

[Matt Fig]

It looks like you are basically doing a 2D convolution:

C2 = conv2(B,A,'valid'); % Look at the corners...

Answer 2

[Andrei Bobrov]

variant

[m1 n1] = size(B);
[m2 n2] = size(A);
Y = reshape(B,m1,n2,[]);
Y1 = permute(Y,[2 1 3]);
Y2 = reshape(Y1,m1,[]);
C = reshape(sum(Y2).*A(:).',m2,[]);

[Oleg Komarov]

Nice one!