www.pudn.com > iriscode.zip > shiftbits.m

% shiftbits - function to shift the bit-wise iris patterns in order to provide the best match 
% each shift is by two bit values and left to right, since one pixel value in the 
% normalised iris pattern gives two bit values in the template 
% also takes into account the number of scales used 
% 
% Usage:  
% [template, mask] = createiristemplate(eyeimage_filename) 
% 
% Arguments: 
%	template        - the template to shift 
%   noshifts        - number of shifts to perform to the right, a negative 
%                     value results in shifting to the left 
%   nscales         - number of filters used for encoding, needed to 
%                     determine how many bits to move in a shift 
% 
% Output: 
%   templatenew     - the shifted template 
% 
% Author:  
% Libor Masek 
% masekl01@csse.uwa.edu.au 
% School of Computer Science & Software Engineering 
% The University of Western Australia 
% November 2003 
 
function templatenew = shiftbits(template, noshifts,nscales) 
 
templatenew = zeros(size(template)); 
 
width = size(template,2); 
s = round(2*nscales*abs(noshifts)); 
p = round(width-s); 
 
if noshifts == 0 
    templatenew = template; 
     
    % if noshifts is negatite then shift towards the left 
elseif noshifts < 0 
     
    x=1:p; 
     
    templatenew(:,x) = template(:,s+x); 
     
    x=(p + 1):width; 
     
    templatenew(:,x) = template(:,x-p); 
     
else 
     
    x=(s+1):width; 
     
    templatenew(:,x) = template(:,x-s); 
     
    x=1:s; 
     
    templatenew(:,x) = template(:,p+x); 
     
end