MATLAB实现2DPCA人脸识别算法

function pca (path, trainList, subDim)  
%  
% PROTOTYPE  
% function pca (path, trainList, subDim)  
%  
% USAGE EXAMPLE(S)  
% pca ('C:/FERET_Normalised/', trainList500Imgs, 200);  
%  
% GENERAL DESCRIPTION  
% Implements the standard Turk-Pentland Eigenfaces method. As a final  
% result, this function saves pcaProj matrix to the disk with all images  
% projected onto the subDim-dimensional subspace found by PCA.  
%  
% REFERENCES  
% M. Turk, A. Pentland, Eigenfaces for Recognition, Journal of Cognitive  
% Neurosicence, Vol. 3, No. 1, 1991, pp. 71-86  
%  
% M.A. Turk, A.P. Pentland, Face Recognition Using Eigenfaces, Proceedings  
% of the IEEE Conference on Computer Vision and Pattern Recognition,  
% 3-6 June 1991, Maui, Hawaii, USA, pp. 586-591  
%  
%  
% INPUTS:  
% path - full path to the normalised images from FERET database  
% trainList - list of images to be used for training. names should be  
% without extension and .pgm will be added automatically  
% subDim - Numer of dimensions to be retained (the desired subspace  
% dimensionality). if this argument is ommited, maximum  
% non-zero dimensions will be retained, i.e. (number of training images) - 1  
%  

% OUTPUTS:  
% Function will generate and save to the disk the following outputs:  
% DATA - matrix where each column is one image reshaped into a vector  
% - this matrix size is (number of pixels) x (number of images), uint8  
% imSpace - same as DATA but only images in the training set  
% psi - mean face (of training images)  
% zeroMeanSpace - mean face subtracted from each row in imSpace  
% pcaEigVals - eigenvalues  
% w - lower dimensional PCA subspace  
% pcaProj - all images projected onto a subDim-dimensional space  
%  
% NOTES / COMMENTS  
% * The following files must either be in the same path as this function  
% or somewhere in Matlab's path:  
% 1. listAll.mat - containing the list of all 3816 FERET images  
%  
% ** Each dimension of the resulting subspace is normalised to unit length  
%  
% *** Developed using Matlab 7  
%  
%  
% REVISION HISTORY  
% -  
%  
% RELATED FUNCTIONS (SEE ALSO)  
% createDistMat, feret  
%  
% ABOUT  
% Created: 03 Sep 2005  
% Last Update: -