MATLAB: Superimposing matrices in a specific location

Question

I have two matrices, one 1024×1024 and one 101×101. 95% of the matrices consists of zeros, besides the central circular parts which have values ranging between 0 and 1. When displayed, the matrices show a circle.

I want to superimpose the smaller matrix onto the larger matrix in a specific location from the origin of the larger matrix. How can I extract the values from the smaller matrix and superimpose them onto the larger matrix?

Thanks

Answer 1

Something like this, perhaps:

[i0,j0]=deal(700,850);  %target location
[I,J,S]=find(smallMatrix);
result = largeMatrix + accumarray([I-51+i0,J-51+j0], S ,[1024,1024]);