MATLAB: Vectorization of for loop

for loop

I have this for loop with conditionals inside it.
for i=1:m
    for j=1:n
        if (flipped_im(i,j,1)>flipped_im(i,j,2)) || (flipped_im(i,j,1)>flipped_im(i,j,3))
            mod_im(i,j,:)=255;
        else
            mod_im(i,j,:)=flipped_im(i,j,:);
        end
    end
end
How I can turn this loop into vectorized code?

Best Answer

In three lines, no loop:
>> new_im = flipped_im;
>> idx = new_im(:,:,1)>new_im(:,:,2) | new_im(:,:,1)>new_im(:,:,3);
>> new_im(idx(:,:,[1,1,1])) = 255;
and checking:
>> isequal(mod_im,new_im)
ans = 1
For MATLAB versions R2016b and later you can simplify the index code:
idx = any(new_im(:,:,1)>new_im(:,:,2:3),3);
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