68 lines
1.7 KiB
Mathematica
68 lines
1.7 KiB
Mathematica
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%--------------------------------------------------------------------------
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% ENSEEIHT - 2SN MM - Traitement des donn<EFBFBD>es audio-visuelles
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% TP6 - Restauration d'images
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% exercice_0 : d<EFBFBD>bruitage avec mod<EFBFBD>le de Tikhonov (niveaux de gris)
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%--------------------------------------------------------------------------
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clear
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close all
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clc
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% Mise en place de la figure pour affichage :
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taille_ecran = get(0,'ScreenSize');
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L = taille_ecran(3);
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H = taille_ecran(4);
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% Lecture de l'image :
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u0 = double(imread('Images/lena_avec_bruit.bmp'));
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image = zeros(size(u0));
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[nb_lignes,nb_colonnes,nb_canaux] = size(u0);
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u_max = max(u0(:));
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% Affichage de l'image :
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% subplot(1,2,1)
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figure;
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imagesc(max(0,min(1,u0/u_max)),[0 1])
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colormap gray
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axis image off
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title('Image bruitee')
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imwrite(max(0,min(1,u0/u_max)), "saves/exo0bis_bruit.png")
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% Vectorisation de u0 :
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nb_pixels = nb_lignes * nb_colonnes;
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for c=1:nb_canaux
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ut = u0(:,:,c);
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ut = reshape(ut, nb_pixels, 1);
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% Op<EFBFBD>rateur gradient :
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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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% Second membre b du syst<EFBFBD>me :
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b = ut;
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% Matrice A du syst<EFBFBD>me :
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Lap = -Dx'*Dx -Dy'*Dy;
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lambda = 2; % Poids de la r<EFBFBD>gularisation
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A = speye(nb_pixels) - lambda*Lap;
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% R<EFBFBD>solution du syst<EFBFBD>me A*u = b :
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u = A\b;
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image(:,:,c) = max(0,min(1,reshape(u,[nb_lignes nb_colonnes])/u_max));
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end
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% Affichage de l'image restaur<EFBFBD>e :
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% subplot(1,2,2)
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figure;
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imagesc(image, [0 1])
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colormap gray
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axis image off
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title('Image restauree')
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imwrite(image, "saves/exo0bis_clean.png")
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