2D baker map code implementation

I am trying to implement the discretized baker map for the shuffling of pixels,i am not able to understand the discretized version of it clearly.and neither am i able to implement it properly on matlab it always show index out of bounds error. here is the link http://link.springer.com/chapter/10.1007/978-3-540-95972-4_16 please can somebody help. I am a beginner and this is my effort at it i know it is pathetic but still.

       for i=1:row
       for j=1:col
       if(1<=j<row/2)
           newcord1=((2*(j-1))+mod(i-1,2));
           newcord2=(floor(0.5*(i-mod(i-1,2))+1));
           im(i,j)=im(newcord2,newcord1);
            elseif(row/2 <=j <=row)
            newcord1=((2*(j-64))+mod(i,2));
            newcord2=floor(0.5*(i-mod(i,2))+63);
            im(i,j)=im(newcord2,newcord1);

       end
  end
  end

[Syahirah Rahim]

Hi. I also a beginner and new to MATLAB. I am trying to code on discretized baker map but I did not really understand.

Could you please tell me how this line works?

newcord1=((2*(j-1))+mod(i-1,2));

newcord2=(floor(0.5*(i-mod(i-1,2))+1));

and also

newcord1=((2*(j-64))+mod(i,2));

newcord2=floor(0.5*(i-mod(i,2))+63);

How can i divide the square size image to few verticle rectangle and implement above code?

[su su maung]

Here is the matlab code for 2D baker map.

#################### Baker Map for 6x6 pixels ###########

A=[1:1:6;7:1:12;13:1:18;19:1:24;25:1:30;31:1:36];

tic;

N0=0;

N1=3;

N2=4;

n1=3;

n2=1;

n3=2;

for i=1:1% 9 times

for r=0:2

for s=0:5

X(r+1,s+1)=A(floor((6/n1)*(r-N0)+mod(s,(6/n1)))+1,floor((n1/6)*(s-mod(s,(6/n1)))+N0)+1);

end

end

for r=3:3

for s=0:5

X(r+1,s+1)=A(floor((6/n2)*(r-N1)+mod(s,(6/n2)))+1,floor((n2/6)*(s-mod(s,(6/n2)))+N1)+1);

end

end

for r=4:5

for s=0:5

X(r+1,s+1)=A(floor((6/n3)*(r-N2)+mod(s,(6/n3)))+1,floor((n3/6)*(s-mod(s,(6/n3)))+N2)+1);

end

end

%A=X;

end

toc

[Parveiz Lone]

what about inverse

[Zeina Abdullah]

Hi , please can you help me i need a chaotic interleaver code using baker map . please tell any thing can help me in my problem . @Parveiz Lone @su su maung @Syahirah Rahim @myetceteramail myetceteramail @Walter Roberson

[Zeina Abdullah]

@su su maung if the input 8*8 how dose the code will be change

Answer 1

[Walter Roberson]

       if(1<=j<row/2)

means

         if ((1<=j)<row/2)

The first part, 1<=j, returns false (0) or true (1). That 0 or 1 is then compared to row/2.

You probably want

         if 1<=j && j<row/2