Image Ciphering Function With Matlab

[metalnumb]

Hey Guys !
I've been woking on this project and i dont know why it does not work....:evil:
its required to make a simple ciphering function for images with any dimension..( just to make its details unclear for example)

function [op]=cphx(ip)

n= ip([end:-1:1],[end:-1:1],:) ;    %  flipped 180 degrees and mirrored.

% Puzzling The Image
%====================
a=n([1:end/2],[1:end/2],:) ;       % i.e (1/4) of the image(dividing the image into 4 chunks)=(A)
b=n([end/2:end],[1:end/2],:) ;     % =(B) 
c=n([1:end/2],[end/2:end],:) ;     % =(C)
d=n([end/2:end],[end/2:end],:) ;   % =(D)
op=[a d;c b];                       % Shuffling the pieces will render the image almost ciphered.

it just gives this error everytime i call the function... :shock:

??? Subscript indices must either be real positive integers or logicals.

Error in ==> cphx at 8
b=n([end/2:end],[1:end/2],:) ;     % =(B)

what am i doing wrong ? please help me out !
thanks in advance !!;-)

 

[blooz]

Here is a good Discussion
h**p://www.mathworks.in/support/tech-notes/1200/1207.html#19