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

% segmentiris - peforms automatic segmentation of the iris region 
% from an eye image. Also isolates noise areas such as occluding 
% eyelids and eyelashes. 
% 
% Usage:  
% [circleiris, circlepupil, imagewithnoise] = segmentiris(image) 
% 
% Arguments: 
%	eyeimage		- the input eye image 
%	 
% Output: 
%	circleiris	    - centre coordinates and radius 
%			          of the detected iris boundary 
%	circlepupil	    - centre coordinates and radius 
%			          of the detected pupil boundary 
%	imagewithnoise	- original eye image, but with 
%			          location of noise marked with 
%			          NaN values 
% 
% Author:  
% Libor Masek 
% masekl01@csse.uwa.edu.au 
% School of Computer Science & Software Engineering 
% The University of Western Australia 
% November 2003 
 
function [circleiris, circlepupil, imagewithnoise] = segmentiris(eyeimage) 
 
% define range of pupil & iris radii 
 
%CASIA 
lpupilradius = 28; 
upupilradius = 75; 
lirisradius = 80; 
uirisradius = 150; 
 
%    %LIONS 
%    lpupilradius = 32; 
%    upupilradius = 85; 
%    lirisradius = 145; 
%    uirisradius = 169; 
 
 
% define scaling factor to speed up Hough transform 
scaling = 0.4; 
 
reflecthres = 240; 
 
% find the iris boundary 
[row, col, r] = findcircle(eyeimage, lirisradius, uirisradius, scaling, 2, 0.20, 0.19, 1.00, 0.00); 
 
circleiris = [row col r]; 
 
rowd = double(row); 
cold = double(col); 
rd = double(r); 
 
irl = round(rowd-rd); 
iru = round(rowd+rd); 
icl = round(cold-rd); 
icu = round(cold+rd); 
 
imgsize = size(eyeimage); 
 
if irl < 1  
    irl = 1; 
end 
 
if icl < 1 
    icl = 1; 
end 
 
if iru > imgsize(1) 
    iru = imgsize(1); 
end 
 
if icu > imgsize(2) 
    icu = imgsize(2); 
end 
 
% to find the inner pupil, use just the region within the previously 
% detected iris boundary 
imagepupil = eyeimage( irl:iru,icl:icu); 
 
%find pupil boundary 
[rowp, colp, r] = findcircle(imagepupil, lpupilradius, upupilradius ,0.6,2,0.25,0.25,1.00,1.00); 
 
rowp = double(rowp); 
colp = double(colp); 
r = double(r);

row = double(irl) + rowp;
col = double(icl) + colp;

row = round(row);
col = round(col); 
 
circlepupil = [row col r]; 
 
% set up array for recording noise regions 
% noise pixels will have NaN values 
imagewithnoise = double(eyeimage); 
 
%find top eyelid 
topeyelid = imagepupil(1:(rowp-r),:); 
lines = findline(topeyelid); 
 
if size(lines,1) > 0 
    [xl yl] = linecoords(lines, size(topeyelid)); 
    yl = double(yl) + irl-1; 
    xl = double(xl) + icl-1; 
     
    yla = max(yl); 
     
    y2 = 1:yla; 
     
    ind3 = sub2ind(size(eyeimage),yl,xl);
    imagewithnoise(ind3) = NaN;
     
    imagewithnoise(y2, xl) = NaN; 
end 
 
%find bottom eyelid 
bottomeyelid = imagepupil((rowp+r):size(imagepupil,1),:); 
lines = findline(bottomeyelid); 
 
if size(lines,1) > 0 
     
    [xl yl] = linecoords(lines, size(bottomeyelid)); 
    yl = double(yl)+ irl+rowp+r-2; 
    xl = double(xl) + icl-1; 
     
    yla = min(yl); 
     
    y2 = yla:size(eyeimage,1); 
     
    ind4 = sub2ind(size(eyeimage),yl,xl); 
    imagewithnoise(ind4) = NaN; 
    imagewithnoise(y2, xl) = NaN; 
     
end 
 
%For CASIA, eliminate eyelashes by thresholding 
ref = eyeimage < 100; 
coords = find(ref==1); 
imagewithnoise(coords) = NaN;