seg.zip_seg_segmentation_zip

% This Matlab program demomstrates the level set algorithm in paper: % "Active contours with selective local or global segmentation: a new variational approach and level set method" % to appear in Image and Vision Computing, 2010. % Authors: Kaihua Zhang, Lei Zhang, Huihui Song and Wengang Zhou % E-mail: zhkhua@mail.ustc.edu.cn, cslzhang@comp.polyu.edu.hk % URL: http://www4.comp.polyu.edu.hk/~cslzhang/ % Notes:Some parameters may need to be modified for different types of images. % Please contact the authors if any problem regarding the choice of parameters. % Date: 5/11/2009 clc;clear all;close all; Img = imread('11.jpg'); Img = Img(:,:,1); Img = double(Img); % Img = 200*ones(100); % Img(20:80,10:30)= 140; % Img(20:80,40:70)= 180; % Img(20:80,80:90)=50; [row,col] = size(Img); phi = ones(row,col); phi(110:row-150,155:col-200) = -1; u = - phi; [c, h] = contour(u, [0 0], 'r'); title('Initial contour'); % hold off; sigma = 0.004; G = fspecial('gaussian', 5, sigma); delt = 0.2; Iter = 400; mu = 18;%this parameter needs to be tuned according to the images for n = 1:Iter [ux, uy] = gradient(u); c1 = sum(sum(Img.*(u<0)))/(sum(sum(u<0)));% we use the standard Heaviside function which yields similar results to regularized one. c2 = sum(sum(Img.*(u>=0)))/(sum(sum(u>=0))); spf = Img - (c1 + c2)/2; spf = spf/(max(abs(spf(:)))); u = u + delt*(mu*spf.*sqrt(ux.^2 + uy.^2)); if mod(n,10)==0 imagesc(Img,[0 255]); colormap(gray);hold on; [c, h] = contour(u/2, [0 0], 'r'); iterNum = [num2str(n), 'iterations']; title(iterNum); pause(0.02); end u = (u >= 0) - ( u< 0);% the selective step. u = conv2(u, G, 'same'); end imagesc(Img,[0 255]);colormap(gray);hold on; [c, h] = contour(u, [0 0], 'b');