You get an error message, if you provide a cell array to the imshow command. Then it i useful to share the message with the readers. It is easier to solve a problem than to guess, what the problem is.
Why do you create c by mat2cell only to overwrite it immediately?
Avoid monsters as:
c=mat2cell(b,[38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38],[25,25,25,25,25,25,25,25,25,25,25,25,25,25,25,25,25,25,25,25,25,25,25,25,25,25,25,25,25,25]);
Easier to read:
c = mat2cell(b, repmat(38, 1, 30), repmat(25, 1, 30));
You can simplify:
for i=1:30
for j=1:30
c{i,j}=a;
end
end
to:
c(:) = {a};
