I am trying to preform SVD Decomposition on a color image. I have attached my code. The main goal is to preform SVD on a color image, and apply various rank approximations. The issue is when i change the rank to k=55, I get a greyscale image and not color. How could I fix this to get a color image when I change the rank?
% Read jpg file
A = imread('woodchuck.jpg');
% Convert to A to double
A = im2double(A);
% Color Channels
R = A(:, :, 1);
G = A(:, :, 2);
B = A(:, :, 3);
% Perform svd
[UR,SR,VR] = svd(R);
[UG,SG,VG] = svd(G);
[UB,SB,VB] = svd(B);
DR = UR*SR*VR';
DG = UG*SG*VG';
DB = UB*SB*VB';
%Create new matrix
% Plot rank 5 approximation, rank 10 approximation, rank 50, and true image
figure('Position',[50 50 800 800])
subplot(2,2,1)
M=zeros(480,640,3);
M(:,:,1) = DR;
M(:,:,2) = DG;
M(:,:,3) = DB;
imshow(M); title ('Original Image')
subplot(2,2,2)
k = 55;
Mk = UR(:,1:k)*SR(1:k, 1:k)* VR(:,1:k)';
Mk = UG(:,1:k)*SG(1:k, 1:k)* VG(:,1:k)';
Mk = UB(:,1:k)*SB(1:k, 1:k)* VB(:,1:k)';
imshow(Mk); title('Rank 55')
