how do I descrambling for the scrambling code explain in below:

origin=imread('lena.bmp');
        imshow(origin)
        title('Image Loaded')
temp=origin;
n=length(temp) 
N=3000; % no of iterartions

m=0;
a=20;
b=10;
c=a*b+1;
flag=0;
while flag==0
    for i=0:n-1                       
        for j=0:n-1
            x=mod(i+a*j,n); 
            y=mod(b*i+c*j,n); 
            lastimage(x+1,y+1)=temp(i+1,j+1);
        end
    end
    m=m+1;
   if(mod(m,4)==0)
        figure,imshow(lastimage)
        title('Scrambled Image')
        flag=flag+1;
   else
      temp=lastimage;
    end
end

[Devisha Tiwari]

The code above performs Arnold's cat map on the lena image.

Answer 1

[Image Analyst]

It looks like you're trying to do Arnold's cat map: Wikipedia Arnold's cat map

See wikipedia and my attached demo, which has LOTS of comments to explain it.

[hayat ali]

Image Analyst

thank you very much.

I just want steps that reflect the previous code steps. can you help me to get it?

[Image Analyst]

Not sure what you want to get. The previous code steps will of course "reflect" the previous code steps. In fact, they are identical. I don't know what steps to tell you to take. Do you mean

1. highlight the code,
2. type control-c, then
3. go somewhere where you want to paste it, and
4. type control-v?

Those steps?

Please format your code as code so that people can easily copy it to the clipboard. Then no one has to mess with highlighting and typing control-c, we can just click the copy link.