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主动轮廓模型（基于GVF和VFC）应用
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文件大小: 4mb
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上传时间: 2010-07-17
详细说明： 使用GVF域和VFC域进行图片分割 % Vector field convolution (VFC) external force field example. % % See also AMT, EXAMPLE_PIG, AM_VFC, AM_VFK, AC_DISPLAY. % % Reference % [1] Bing Li and Scott T. Acton, "Active contour external force using % vector field convolution for image segmentation," Image Processing, % IEEE Trans. on, vol. 16, pp. 2096-2106, 2007. % [2] Bing Li and Scott T. Acton, "Automatic Active Model % Initialization via Poisson Inverse Gradient," Image Processing, % IEEE Tra ns. on, vol. 17, pp. 1406-1420, 2008. % % (c) Copyright Bing Li 2005 - 2009. clear all disp('======================================') disp('Vector field convolution (VFC) example') %% parameter settings disp('Initializing parameters ...') SAVE_AVI = 0; % set it to 1 if you want to save the process as .avi movie DISPLAY_STREAMLINE = 0; % set it to 1 if you want to plot streamlines, note that it takes a while mu = .2; GVF_ITER = 100; normalize = 1; alpha = .5; beta = 0; tau = .5; SNAKE_ITER = 5; SNAKE_ITER1 = 60; RES = .5; clr = {'b' 'b' 'r'}; %% Read images disp('Reading images ...') U = imread('im_U.bmp'); noisyU=imread('im_Unoisy.bmp'); figure(1) %% compare 3 different cases for cs = 1:3, %% compute external force fields switch cs, case 1, % traditional GVF with Gaussian filter disp('--------------------------------------------------') disp('Case 1: GVF snake with initial circle close to FOI') disp('Computing the external force field ...') h = fspecial('gaussian',[5 5],5); f = imfilter(double(noisyU),h); titl = 'GVF'; Fext = AM_GVF(f, mu, GVF_ITER, normalize); R = 20; case 2, % traditional GVF with Gaussian filter disp('--------------------------------------------------') disp('Case 2: GVF snake with initial circle far away from FOI') disp('Computing the external force field ...') h = fspecial('gaussian',[5 5],5); f = imfilter(double(noisyU),h); titl = 'GVF'; Fext = AM_GVF(f, mu, GVF_ITER, normalize); R = 28; case 3, % VFC disp('--------------------------------------------------') disp('Case 3: VFC snake with initial circle far away from FOI') disp('Computing the external force field ...') f = noisyU; K = AM_VFK(2, 32, 'power',1.8); Fext = AM_VFC(f, K, 1); R = 28; titl = 'VFC'; end %% display I = (1-noisyU)*.3+.7; % for display subplot(2,3,cs) disp('Displaying the external force field ...') if DISPLAY_STREAMLINE, cla [x y] = meshgrid(.5:64,.5:64); vt = [x(:) y(:)]; % seeds VT = zeros([size(vt) 40]); VT(:,:,1) = vt; for i=1:39, % moving these seeds vt = AC_deform(vt,0,0,tau,Fext,1); VT(:,:,i+1) = vt; end [Ty Tx] = find(~U); % ground truth hold on for i=1:size(vt,1), if min(abs(VT(i,1,end)-Tx)+abs(VT(i,2,end)-Ty))<=2, % converge to U-shape plot(squeeze(VT(i,1,:)), squeeze(VT(i,2,:)),'r','linewidth',1) else plot(squeeze(VT(i,1,:)), squeeze(VT(i,2,:)),'k','linewidth',1) end end hold off axis equal; axis 'ij'; axis([1 64 1 64]) else AC_quiver(Fext, I); title(['normalized ',titl,' field']); end %% uncomment these 2 lines to save the display % F = getframe(gca); % imwrite(F.cdata,['vector_field',num2str(cs),'.bmp']); %% initialize a circle at (32 32) with radius R disp('Initializing the snake ...') vert = AC_initial(RES, 'circle', [32 32 R]); vert0 = vert; subplot(2,3,3+cs) imshow(I) AC_display(vert,'close',clr{cs}); drawnow, pause(.5) if SAVE_AVI mov = avifile(['example_vfc_',num2str(cs),'.avi'],'fps',4,'quality',100,'compression','None'); frame = getframe(gca); mov = addframe(mov,frame); end disp('Deforming the snake ...') for i=1:SNAKE_ITER1, vert = AC_deform(vert,alpha,beta,tau,Fext,SNAKE_ITER); vert = AC_remesh(vert,.5); if mod(i,2)==0, imshow(I) h=AC_display(vert,'close',clr{cs}); h=AC_display(vert0,'close',[clr{cs} '--']); title([titl ' iteration ' num2str(i)]) drawnow, pause(.5) end if SAVE_AVI frame = getframe(gca); mov = addframe(mov,frame); end end disp('Done!') if SAVE_AVI h=close(mov); end end ...展开收缩
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