what is the exact differance between PCA and MPCA , and how to apply this to an image with N*N , wikipidea says PCA operates on image with 100*100 pixel , with 10,000*1, where as MPCA operates on same image with TWO mode as 100* 1, 100*1.

wikipidea says PCA operates on image with 100*100 pixel with 10,000*1 in sigle mode , where as MPCA operates on same image with TWO mode as 100*1, 100*1.what it means , and how to implement this in MATLAB, i have tried to do this , please check this code, if any one have any code which will differentiate the PCA and MPCA for image, or any further reading pleas guide me.

i am attaching my code of MPCA here

if true
  % clear all;
close all;
clc;
[f p]=uigetfile('*.*','');
path=[p f];
Img=imread(path);
Img=rgb2gray(Img);
figure;
imshow(Img)
title('Input Image')
FaceNo=4;

IMat=[];

for i=1:FaceNo

    s=num2str(i);
    s=[ s '.jpg'];
    imr=imread(s);
    t = imresize(imr,[500 500]);
   % t=imread(s);
    t=rgb2gray(t);
    figure,imshow(t);
    IMat(:,:,i)=t;

end

IMat=uint8(IMat);

% image vector

[rw cl]=size(IMat(:,:,1));

for i=1:FaceNo

    IVect(:,i)=reshape(IMat(:,:,i),rw*cl,1);

end

% mean image

IMean=mean(IVect,2);

IMean=uint8(IMean);

% substract mean image from image vector

mn=[];

for i=1:FaceNo

    mn=[mn IMean];

end

IVMean=IVect-mn;

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% calculate covariance matrix

CVMat=double(IVMean)'*double(IVMean);

% calculate eigen values and eigen vectors

[eigVal eigVec]=eig(CVMat);

eigVec=single(IVMean)*eigVec;

eigFace=eigVec(:,end:-1:1);

% face space projection

[r c]=size(IVMean); Wt=zeros(c,FaceNo);

for i=1:c

    Wt(i,:)=single(IVMean(:,i))'*eigVec;

end