52 lines
1.2 KiB
Matlab
52 lines
1.2 KiB
Matlab
function u = collage(r, s, interieur)
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r = double(r);
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s = double(s);
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[nb_lignes,nb_colonnes,nb_canaux] = size(r);
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nb_pixels = nb_lignes * nb_colonnes;
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e = ones(nb_pixels, 1);
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Dx = spdiags([-e e],[0 nb_lignes], nb_pixels, nb_pixels);
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Dx(end-nb_lignes+1:end,:) = 0;
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Dy = spdiags([-e e],[0 1],nb_pixels, nb_pixels);
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Dy(nb_lignes:nb_lignes:end,:) = 0;
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X = zeros(size(r(:,:,1)));
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X(1, :) = 1;
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X(nb_lignes, :) = 1;
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X(:, 1) = 1;
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X(:, nb_colonnes) = 1;
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indices_bord_r = find(X);
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n_bord_r = length(indices_bord_r);
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n_r = nb_pixels;
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A = Dx' * Dx + Dy' * Dy;
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A(indices_bord_r,:) = sparse(1:n_bord_r,indices_bord_r,ones(n_bord_r,1),n_bord_r,n_r);
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% Calcul de l'imagette résultat u, canal par canal :
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u = r;
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for k = 1:nb_canaux
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u_k = u(:,:,k);
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s_k = s(:,:,k);
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r_k = r(:,:,k);
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grad_s = [Dx * s_k(:) , Dy * s_k(:)];
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grad_r = [Dx * u_k(:) , Dy * u_k(:)];
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grad_g = grad_r;
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grad_g(interieur, :) = grad_s(interieur, :);
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b = Dx' * grad_g(:,1) + Dy' * grad_g(:,2);
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b(indices_bord_r) = r_k(indices_bord_r);
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u_k = -A \ -b;
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u_k = reshape(u_k, nb_lignes, nb_colonnes);
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u(:,:,k) = u_k;
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end
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