Subtracting two matrices of different size element by element

Hi every one

is there any way how to subtradt two matrices of different dimension let say A=ones(40) and B=ones(12)

How can we perform subtraction like S=A-B.

Thanks

Answer 1

[Azzi Abdelmalek]

% ----------your data-------
x=magic(4);
y=magic(2);
%-----------The code-----------
[n,m]=size(x);
[n1,m1]=size(y);
z=zeros(n,m);
z(1:n1,1:m1)=y
out=x-z

[rana Banik]

doesn't work! I have this function to perform.

distance=IMM-c;
>>whos
IMM= 132x116x2  double
c= 132x348x2 double

I have also performed bsxfun command but each time command window says error in array mismatch!!! have any other way ??

[Image Analyst]

Azzi's method does not subtract the entire arrays - that is impossible. You either have to resize one of them like I suggested in my answer, or just subtract some overlapping part, like Azzi's answer which the original poster accepted. rana, for your situation you need to subtract only the first 116 columns

distance = IMM - c(:,1:size(IMM, 2), :);

It would be more robust to actually take the minimum of each dimension of the two arrays to determine the ending row, column, and third dimension.

Answer 2

[Image Analyst]

Not unless you resize one of them. But actually we'd need an actual example with actual arrays so we can understand your thought process. Please give us an example where it does exactly what you want and we can maybe tell you how to achieve that.

[Algorithms Analyst]

let say that I have RGB image and I am extracting Rchannel from it

Rchannel=rgbimage(:,:,1); Block1=Rchannel(1:12,1:12); Block2=Gchannel(1:40,1:40)

I need Block1-Block2???????

[Algorithms Analyst]

Actaully implementing some algorithm....so this is requirement..

[Thorsten]

It would be helpful if you give an example, e.g., what should be the result of

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