Pca implemetation on an image

Question

hi!
i have to get luminance image of an original image by applying pca on the originol one. i have done my work but here is a problem. i want to get luminance image by applying pca but the resultant image is not clear. here is the attached vi. would u plz  see it and correct it for me? i have got the luminance image through many simple ways but i have to do this by pca. i think the problem is in the final result, the result of multiplication , i have to increase its values by some way. but i dont know that way.. kindly help me.
thnx in advanc
Attachments:
Attachments:
lumi img pca.vi ‏84 KB

Answer 1

hi David.
i have to get luminance image by first getting pca coefficients and then doing some operation on these coefficient matrix.
here is the code in matlab. this is a function that i have called in original programe.
function [luminance] = PCA1(RGB)
% USAGE [luminance channel] = PCA1(RGB)
% INPUT
% RGB: rgb image
% OUTPUT
% luminance channel:
% from matrix representation to vector
r = RGB(:,:,1);
g = RGB(:,:,2);
b = RGB(:,:,3);
[rS cS d] = size(RGB);
rVec = r(;
gVec = g(;
bVec = b(;
Ivec = cat(2,rVec,gVec,bVec);
% compute eigen vector
[eigenVec score eigenVal ts] = princomp(Ivec);
figure
imshow(eigenVec)
% the luminance is normalized to 1
V = eigenVec/(sum(eigenVec(:,1)));
figure
imshow(V)
% transformation from RGB to PCA representation
Bvec = Ivec*V;
% from vector representation to matrix
luminance = reshape(Bvec(:,1),rS,cS);
i have implemented it in lab view but the result is not clear. 
here are the attachements. the first 1 shows u the originol image and result in matlab and 2nd shows the result that i have got in lab view by operating above vi.
plz help me asap.
thnx
kitty14
Attachments:
pic2.png ‏619 KB
pic 3.png ‏57 KB