image scrambling in matlab
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i want to simply divide a given digital image into small segments and scramble them(jumble). thus encrypting them and also decrypt them.plz help
3 Comments
Accepted Answer
Jan
on 6 Aug 2013
Edited: Jan
on 7 Aug 2013
If you are talking about an RGB image:
img = rand(100, 100, 3);
block = reshape(img, [10, 10, 10, 10, 3]);
block = permute(block, [1, 3, 2, 4, 5]);
block = reshape(block, [100, 10, 10, 3]);
mix = randperm(100);
scrambled = reshape(block(mix, :, :, :), 100, 100, 3); % EDITED: reshape added
And the descrambling runs the other way around.
7 Comments
Manpreet
on 27 Apr 2015
Sir, On reshaping we will get a new image which will contains scrambled value only not image pixels value.
Walter Roberson
on 4 May 2015
No, Manpreet, the code Jan provided moves all three bit planes for a pixel together and does not change the representation. Every output pixels has an RGB that can be tracked directly to an input pixel. If you wish to verify this experimentally then replace Jan's original line
img = rand(100,100,3);
with
img = repmat(reshape(1:100*100)/(100*100),[100,100]), [1, 1, 3]);
this will produce an RGB image containing shades of grey, with the R, G, and B all being the same. You can image() it to observe this. Then when you look at the resulting image "scrambled" you will find that it continues to contain shades of grey and that the R, G, and B planes for any one location are all the same, and differ from every other location; this establishes that the planes were all moved together and establishes that the values are just moved around, not calculated or interpolated.
More Answers (1)
Image Analyst
on 5 Aug 2013
Try the File Exchange, and you might find similar things to what you want, such as the 15 tile sliding puzzles:
1 Comment
Image Analyst
on 5 Sep 2013
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