## Remove white padding from image

### YT (view profile)

on 14 Oct 2018
Latest activity Answered by Image Analyst

on 14 Oct 2018

### Walter Roberson (view profile)

I want to remove white padding from an image (see attachment). The size of the padding is random.
So I was thinking of reading in the image and then some looping to check if the entire row/column contains the value 255. However, looping is most of the time not the best way to do stuff. So I'm wondering if there's an easier way to do this, because I've found a similar question where the rows/columns contain 0, but I don't know if this can also be used for this case (with some adjustments).

### Walter Roberson (view profile)

on 14 Oct 2018

W = all(I == 255, 3);
J = I;
image(J)

YT

### YT (view profile)

on 14 Oct 2018
While I'll accept this answer because it helped me out, the result of your code will not remove the padding from the image but rather makes it black (changes 255 to 0).
With that being said, I combined this answer and the answer you provided in the question I mentioned earlier to fix the issue.
[~,~,d] = size(I);
%255 to 0
W = all(I == 255, 3);
J = I;
% remove 0 rows/columns from R/G/B
for i = 1:d
K = J(:,:,i);
K( ~any(K,2), : ) = []; %rows
K( :, ~any(K,1) ) = []; %columns
switch i
case 1
R = K;
case 2
G = K;
case 3
B = K;
otherwise
warning('Unexpected value');
end
end
IM = cat(3, R, G, B);
imshow(IM);
Walter Roberson

### Walter Roberson (view profile)

on 14 Oct 2018
"remove white padding" is ambiguous as to whether it should be transformed to a different color or cropped out of the image.
W = all(I == 255, 3);
imshow(IM);

### Image Analyst (view profile)

on 14 Oct 2018

Try this:
subplot(2, 2, 1);
imshow(rgbImage);
title('Original RGB Image', 'FontSize', 20);
axis('on', 'image');
nonWhitePixels = any(rgbImage ~= 255, 3);
subplot(2, 2, 2);
imshow(nonWhitePixels)