Why i didnt get the image back during decryption using this inverse code ?
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I used the below code for image scrambling and unscrambling. But i didnt get the exact image in unscrambling. In the decrypted image the upper portion is at the bottom position, that is the hat in the lena image comes at bottom. Please help me to rectify it.
ite=1;
[rown,coln]=size(im);
 for i=1:rown
        for j=1:coln
         itecount=1;
         nrowp=i;
         ncolp=j;
          while(itecount<=ite)
                       newcord =[1 1;1 2]*[nrowp ncolp]';
                       nrowp=newcord(1);
                       ncolp=newcord(2);
                       itecount=itecount+1;
                      end 
            encim(i,j)=im((mod(nrowp,rown)+1),(mod(ncolp,coln)+1));
        end
 end
%INVERSE
figure,imshow(im)
impixelinfo
figure,imshow(uint8(encim))
impixelinfo
[rown,coln]=size(encim)
for i=1:rown
        for j=1:coln
         itecount=1;
         nrowp=i;
         ncolp=j;
          while(itecount<=ite)
                       newcord =[2 -1;-1 1]*[nrowp-1 ncolp-1]';
                       nrowp=newcord(1);
                       ncolp=newcord(2);
                       itecount=itecount+1;
                      end
            decim(i,j)=encim((mod(nrowp,rown)+1),(mod(ncolp,coln)+1));
        end
 end
figure,imshow(uint8(decim))
impixelinfo
4 Comments
  Jan
      
      
 on 8 Mar 2018
				@Sneha P S: There is no need to be sorry. But let me mention, that your code is still not formatted properly. Now there is a blank line after each line of code, some parts are recognized as code (due to the leading spaces), but some are not. Please read: Tutorial: How to format text in the forum.
Answers (1)
  Image Analyst
      
      
 on 9 Mar 2018
        I'm not sure what this uncommented code does. Is it the Arnold cat map? Just regular scrambling? I'm attaching demos for both. Since I don't know what your image does (due to lack of comments/explanations), I don't know how to fix it.
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