matlab虹膜识别的边缘提取

% normaliseiris - performs normalisation of the iris region by % unwraping the circular region into a rectangular block of % constant dimensions.（归一化操作） % % Usage: % [polar_array, polar_noise] = normaliseiris(image, x_iris, y_iris, r_iris,... % x_pupil, y_pupil, r_pupil,eyeimage_filename, radpixels, angulardiv) % % Arguments: % image - the input eye image to extract iris data from % x_iris - the x coordinate of the circle defining the iris % boundary % y_iris - the y coordinate of the circle defining the iris % boundary % r_iris - the radius of the circle defining the iris % boundary % x_pupil - the x coordinate of the circle defining the pupil % boundary % y_pupil - the y coordinate of the circle defining the pupil % boundary % r_pupil - the radius of the circle defining the pupil % boundary % eyeimage_filename - original filename of the input eye image % radpixels - radial resolution, defines vertical dimension of % normalised representation % angulardiv - angular resolution, defines horizontal dimension % of normalised representation % % Output: % polar_array % polar_noise % % Author: % Libor Masek % masekl01@csse.uwa.edu.au % School of Computer Science & Software Engineering % The University of Western Australia % November 2003 function [polar_array, polar_noise] = normaliseiris(image, x_iris, y_iris, r_iris,... x_pupil, y_pupil, r_pupil,eyeimage_filename, radpixels, angulardiv,write) global DIAGPATH radiuspixels = radpixels + 2; angledivisions = angulardiv-1; r = 0:(radiuspixels-1); theta = 0:2*pi/angledivisions:2*pi; x_iris = double(x_iris); y_iris = double(y_iris); r_iris = double(r_iris); x_pupil = double(x_pupil); y_pupil = double(y_pupil); r_pupil = double(r_pupil); % calculate displacement of pupil center from the iris center ox = x_pupil - x_iris; oy = y_pupil - y_iris; if ox <= 0 sgn = -1; elseif ox > 0 sgn = 1; end if ox==0 && oy > 0 sgn = 1; end r = double(r); theta = double(theta); a = ones(1,angledivisions+1)* (ox^2 + oy^2); % need to do something for ox = 0 if ox == 0 phi = pi/2; else phi = atan(oy/ox); end b = sgn.*cos(pi - phi - theta);%theta是pupil半径射线和以右手方向伪正向的x轴的夹角 % calculate radius around the iris as a function of the angle r = (sqrt(a).*b) + ( sqrt( a.*(b.^2) - (a - (r_iris^2))));%pupil中心到iris边界的距离 r = r - r_pupil; rmat = ones(1,radiuspixels)'*r; rmat = rmat.* (ones(angledivisions+1,1)*[0:1/(radiuspixels-1):1])'; rmat = rmat + r_pupil; % exclude values at the boundary of the pupil iris border, and the iris scelra border % as these may not correspond to areas in the iris region and will introduce noise. % % ie don't take the outside rings as iris data. rmat = rmat(2:(radiuspixels-1), :); % calculate cartesian location of each data point around the circular iris % region xcosmat = ones(radiuspixels-2,1)*cos(theta); xsinmat = ones(radiuspixels-2,1)*sin(theta); xo = rmat.*xcosmat; yo = rmat.*xsinmat; xo = x_pupil+xo; yo = y_pupil-yo; % extract intensity values into the normalised polar representation through % interpolation [x,y] = meshgrid(1:size(image,2),1:size(image,1)); polar_array = interp2(x,y,image,xo,yo); % create noise array with location of NaNs in polar_array polar_noise = zeros(size(polar_array)); coords = find(isnan(polar_array)); polar_noise(coords) = 1; polar_array = double(polar_array)./255; % start diagnostics, writing out eye image with rings overlayed % get rid of outling points in order to write out the circular pattern coords = find(xo > size(image,2)); xo(coords) = size(image,2); coords = find(xo < 1); xo(coords) = 1; coords = find(yo > size(image,1)); yo(coords) = size(image,1); coords = find(yo<1); yo(coords) = 1; xo = round(xo); yo = round(yo); xo = int32(xo); yo = int32(yo); ind1 = sub2ind(size(image),double(yo),double(xo)); image = uint8(image); image(ind1) = 255; %get pixel coords for circle around iris [x,y] = circlecoords([x_iris,y_iris],r_iris,size(image)); ind2 = sub2ind(size(image),double(y),double(x)); %get pixel coords for circle around pupil [xp,yp] = circlecoords([x_pupil,y_pupil],r_pupil,size(image)); ind1 = sub2ind(size(image),double(yp),double(xp)); image(ind2) = 255; image(ind1) = 255; % write out rings overlaying original iris image % w = cd; % cd(DIAGPATH); % imwrite(image,[eyeimage_filename,'-normal.jpg'],'jpg');%写出归一化后的图像 if write pos = findstr(eyeimage_filename,'\'); l=length(pos); posdot = findstr(eyeimage_filename,'.'); addpos = pos(l); final_normal = [eyeimage_filename(1:addpos),'normal-',eyeimage_filename(addpos+1:posdot),'.jpg']; % imwrite(image,final_normal,'jpg');%写出归一化后的图像 % % cd(w); end % end diagnostics %replace NaNs before performing feature encoding coords = find(isnan(polar_array)); polar_array2 = polar_array; polar_array2(coords) = 0.5; avg = sum(sum(polar_array2)) / (size(polar_array,1)*size(polar_array,2)); polar_array(coords) = avg;