function activeContoursNoEdges(ima, con)
    
    warning off;

    % Read input image.
    u0=imread(ima);
    % Convert image to grayscale if necessary.
    if size(size(u0),2) == 3 
        u0=rgb2gray(u0);
    end
    u0=double(u0)/255;
    u0=imresize(u0,0.5);
    

%     % For the weak gradient image.
%     % Parameters of the method.
%     mu=0;
%     lambda1=1;
%     lambda2=1;
%     v=0;
%     ite=1000;
%     epsilon=2;
%     dt=5;
 
    
    
    % Parameters of the method.
    mu=0.01;
    lambda1=1;
    lambda2=1;
    v=0;
    ite=1000;
    epsilon=2;
    dt=1;
    
    % Figure that will hold the contour.
    figContour=figure;
    set(figContour,'Position',[200 350 150 150],'Color',[1 1 1],'Visible','off');
    
    % Figure that will hold the corresponding segmentation.
    figSeg=figure;
    set(figSeg,'Position',[650 350 150 150],'Color',[1 1 1],'Visible','off');
    
    
    if nargin > 1 && con==1
        
       % Allow marking the original contour.
        figure;
        set(figContour,'Position',[200 150 150 150],'Color',[1 1 1]);
        imshow(u0,'InitialMagnification',300);
        [x,y]=ginput(2);
        
        x=min(max(x,1),size(u0,2));
        y=min(max(y,1),size(u0,1));
    
        phi=-ones(size(u0));
        phi(y(1,1) : y(2,1), x(1,1) : x(2,1))=1;
    
        close;
    else
    
        % Setting the initial contour as a small square in the center.
        phi=-ones(size(u0));
        phi(size(u0,1)/4+4 : end-size(u0,1)/4-3, size(u0,2)/4+4 : end-size(u0,2)/4-3)=1;
    end
    
    % Derivative operators gx,gy.
    gx=fspecial('prewitt')/6;
    gy=gx';
    
    for t=1:ite

        % Computing H2eps(phi).
        H2eps=0.5*(1+(2/pi)*atan(phi/epsilon));

        % Computing delta phi.
        deltaPhiX=imfilter(H2eps,gx,'replicate');
        deltaPhiY=imfilter(H2eps,gy,'replicate');
        deltaPhi=sqrt((deltaPhiX.^2 + deltaPhiY.^2));
        
        % Computing c1 and c2
        c1=mean( u0(phi>=0) );
        c2=mean( u0(phi<0)  );
        
        % Computing |del phi|.
        [delPhiX,delPhiY]=gradient(phi);
        normDelPhi=sqrt(delPhiX.^2+delPhiY.^2)+eps;
        
        % Compute the gradient of phi and then the divergent.
        [gradPhiX,gradPhiY]=gradient(phi);
        divX=imfilter(gradPhiX./normDelPhi,gx,'replicate');
        divY=imfilter(gradPhiY./normDelPhi,gy,'replicate');
        div=divX+divY;
        
        % Compute the time increment.
        dphiT=dt.*deltaPhi.*(mu*div-v-lambda1*(u0-c1).^2+lambda2*(u0-c2).^2);
        
        % Integrate phi.
        phi=phi+dphiT;

        % Display phi's derivative.
        displayContour(phi, deltaPhi, u0, figContour, figSeg, t);
        
    end

    %figure(f2);
    %imshow(phi,'InitialMagnification',300);
    %imshow();
    title('Active contours without edges, Chan and Vese')
   

end

function displayContour(phi, deltaPhi, u0, figContour, figSeg, t)

        % Plot the image iteration by iteration.
        rgbDeltaPhi=zeros([size(deltaPhi),3]);
        rgbDeltaPhi(:,:,1)=(deltaPhi>0.075);
        
        rgbU0=zeros([size(u0),3]);
        rgbU0(:,:,1)=u0;
        rgbU0(:,:,2)=u0;
        rgbU0(:,:,3)=u0;
        
        figure(figContour);
        imshow(rgbDeltaPhi+rgbU0,'InitialMagnification',300);
        text(5,5,['Ite: ',num2str(t)],'Color', 'b','FontWeight','bold','FontSize',12);
        
        figure(figSeg);    
        imshow(phi,'InitialMagnification',300)
        text(5,5,['Ite: ',num2str(t)],'Color', 'b','FontWeight','bold','FontSize',12);

        
end