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clear all
close all
%%%%%%%%%%%%%%%% Lecture de l'image %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
I=imread('image_test1.bmp');
I=rgb2gray(I);
I=double(I)/255;
[ms,ns]=size(I);
centreI = round(size(I)/2) + [1 1]; % point central
% figure,imshow(I)
%%%%%%%%%%%%%%%% Génération des points du contour %%%%%%%%%%%%%%%%%%
x0=0;
y0=0;
r0=50;
x=1;
y=1;
[latc1,longc1] = scircle1(x0,y0,r0);
taux=0.00005;
for i0=0:90:270
for j0=15:15:90
[latc,longc] = scircle1(x0,y0,r0,[i0,i0+j0]);
if (i0+j0)>0 & (i0+j0)<=90
tabx(x)=min(latc)+centreI(1);
taby(y)=max(longc)+centreI(2);
x=x+1;
y=y+1;
elseif (i0+j0)>90 & (i0+j0)<=180
tabx(x)=min(latc)+centreI(1);
taby(y)=min(longc)+centreI(2);
x=x+1;
y=y+1;
elseif (i0+j0)>180 & (i0+j0)<=270
tabx(x)=max(latc)+centreI(1);
taby(y)=min(longc)+centreI(2);
x=x+1;
y=y+1;
elseif (i0+j0)> 270 & (i0+j0)<=360
tabx(x)=max(latc)+centreI(1);
taby(y)=max(longc)+centreI(2);
x=x+1;
y=y+1;
end
end
end
tabx;
taby;
I1=zeros(ms,ns);
for i=1:ms
for j=1:ns
for k=1:length(tabx)
if i==round(tabx(k)) & j==round(taby(k))
I1(i,j)=255;
end
end
end
end
% figure,imshow(I1)
I2=I+I1;
figure, imshow(I2)
%%%%%%%%%%%%%%%%% Génération de la matrice identité %%%%%%%%%%%%%%%
n=size(tabx,2);
Id=eye(n);
%%%%%%%%%%%%%%%% Génération du pas h %%%%%%%%%%%%%%%%%%%%%%%%%%%%%
h=(2*pi*r0)/n;
%%%%%%%%%%%%%%%% Génération de la matrice A %%%%%%%%%%%%%%%%%%%%%%%
w1=h*h;
w2=h*h*h*h;
alpha=w2/h^4;
beta=-(w1/h^2)-(4*w2/h^4);
gamma=(2*w1/h^2)+(6*w2/h^4);
vect=gamma*ones(1,n);
mgamma=diag(vect);
mubeta=triu(beta*ones(n,n),1)+triu(-beta*ones(n,n),2);
mlbeta=tril(beta*ones(n,n),-1)+tril(-beta*ones(n,n),-2);
mualpha=triu(alpha*ones(n,n),2)+triu(-alpha*ones(n,n),3);
mlalpha=tril(alpha*ones(n,n),-2)+tril(-alpha*ones(n,n),-3);
A=mlalpha+mlbeta+mgamma+mubeta+mualpha;
%%%%%%%%%%%%%%%%%% matrice inverse %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
mat1=inv(Id+taux*A);
%%%%%%%%%%%%%%%% Gradient de l'image %%%%%%%%%%%%%%%%%%%%%%%%%%%%%
lambda=1;
% P=-edge(I,'canny');
hor=fspecial('prewitt');
ver=hor';
Gh=-filter2(hor,I);
Gv=-filter2(ver,I);
P=-lambda*(Gh.*Gh+Gv.*Gv);
% % [Fx,Fy]=gradient(P);
Fx=-filter2(ver,P);
Fy=-filter2(hor,P);
% %%%%%%%%%%%%%%%%%% itération %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
difference=100*ones(n,2);
V=[tabx;taby]';
nitera=0;
%% EVOLUTION DU SNAKE
% while difference
for iter=1:100000
% Extrapolation du terme de force exterieure
FintX=[0;0];
FintY=[0;0];
for i=1:n
Vx=round(tabx(i));
Vy=round(taby(i));
FintX=[FintX;Fx(Vx,Vy)+Fx(Vx+1,Vy+1)+Fx(Vx+1,Vy)+Fx(Vx,Vy+1)];
FintY=[FintY;Fy(Vx,Vy)+Fy(Vx+1,Vy+1)+Fy(Vx+1,Vy)+Fy(Vx,Vy+1)];
end
FintX1=FintX(3:(n+2));
FintY1=FintY(3:(n+2));
% Calcul de la deformation du snake
m=[FintX1,FintY1];
mm=(V+taux*m);
Vnew=mat1*mm;
% Visualisation du snake
Isnake=zeros(ms,ns);
for i = 1:n
Sx=ceil(Vnew(i,1));
Sy=ceil(Vnew(i,2));
Isnake(Sx,Sy)=255;
end
evol=I+Isnake;
difference=abs(Vnew-V);
V=Vnew;
tabx=Vnew(:,1);
taby=Vnew(:,2);
nitera=nitera+1;
if difference < 0.000005*ones(n,2), break ,end
end
nitera
% figure,imshow(Isnake);
figure,imshow(evol); |
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