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pca implemetation on an image

hi, i want to perform pca on an image to get luminance image. i have done the same thing in matlab and now want to implement it in labview. but i m so confused,,, i have used imaqcolorimagetoarray vi to convert image first to array and then apply pca on it... but the array of rgb image is a 2d matrix but in matlab it is a 3d matrix,, the result of pca here and princomp in matlab is also different ... plz tell me how can i get it,,   thnx ,, here is the  code for pca in matlab

it is a function that is called in the original program ....


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);
% the luminance is normalized to 1
V = eigenVec/(sum(eigenVec(:,1)));


% transformation from RGB to PCA representation
Bvec = Ivec*V

% from vector representation to matrix
luminance = reshape(Bvec(:,1),rS,cS)

 

plz help me as i m new in labview 😞 

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Message 1 of 8
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The easiest way to get the luminance plane is to call IMAQ ExtractColorPlanes or IMAQ ExtractSingleColorPlane.

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Message 2 of 8
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yup i kow thai is easiest way, but problem is that i have to get luminance image by applying PCA

is there any method to apply PCA on an image directly

i have first change the image in array form but that is a 2d array but in matlab that is 3d array for an image how can i get a 3d array of an image direct.. where the 3rd dimension shows the RGB values

plz plz help me :(Smiley Sad

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Message 3 of 8
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why nobody replied me ??????//

plzzzzzzzzzzzzzzzz tell me 

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Message 4 of 8
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You can use a combination of IMAQ ExtractColorPlanes, IMAQ ImagetoArray, IMAQ ColorImagetoArray and NI_AALPro.lvlib:Eigenvalues and Vectors (located in the Mathematics>>Linear Algebra palette) to implement the algorithm you described.

 

 

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Message 5 of 8
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thnx

but what is the ni-aalprovi?

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Message 6 of 8
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NI_AALPro.lvlib refers to the Advanced Analysis LabVIEW Library that the VI belongs to. You can find it in the Mathematics>>Linear Algebra palette.

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Message 7 of 8
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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  usee it and correct it for me?

thnx in advance..

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Message 8 of 8
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