PCATutorial.cpp

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//===========================================================================
/*!
 * 
 *
 * \brief       Principal Component Analysis Tutorial Sample Code
 * 
 * This file is part of the "Principal Component Analysis" tutorial.
 * The tutorial requires that you download the Cambridge Face Database
 * from http://www.cl.cam.ac.uk/research/dtg/attarchive/facedatabase.html
 * and adjust the facedirectory path to the directory containing the faces
 * in PGM format.
 * 
 * You need the libraries boost_serialization, boost_system, and 
 * boost_filesystem for this example.
 * 
 * 
 *
 * \author      C. Igel
 * \date        2011
 *
 *
 * \par Copyright 1995-2017 Shark Development Team
 * 
 * <BR><HR>
 * This file is part of Shark.
 * <https://shark-ml.github.io/Shark/>
 * 
 * Shark is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published 
 * by the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * Shark is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with Shark.  If not, see <http://www.gnu.org/licenses/>.
 *
 */
//===========================================================================
 
#include <shark/Algorithms/Trainers/PCA.h>
#include <shark/Data/Pgm.h>
 
#include <fstream>
#include <boost/format.hpp>
 
using namespace std;
using namespace shark;
 
 
int main(){
    // read image data
    const char *facedirectory = "Cambridge_FaceDB"; //< set this to the directory containing the face database
    UnlabeledData<RealVector> images;
    cout << "Read images ... " << flush;
    try {
        importPGMSet(facedirectory, images);
    } catch(...) {
        cerr << "[PCATutorial] could not open face database directory\n\nThis file is part of the \"Principal Component Analysis\" tutorial.\nThe tutorial requires that you download the Cambridge Face Database\nfrom http://www.cl.cam.ac.uk/research/dtg/attarchive/facedatabase.html\nand adjust the facedirectory path in the source code to the directory\ncontaining the faces in PGM format." << endl;
        return 1;
    }
    cout << "done." << endl;
    
    unsigned l = images.numberOfElements();   // number of samples
    unsigned x = images.shape()[1]; // width of images
    unsigned y = images.shape()[0]; // height of images
    
    cout << "Eigenvalue decomposition ... " << flush;
    PCA pca(images);
    cout << "done." << endl;
    
    cout << "Writing mean face and eigenvalues... " << flush;
    ofstream ofs("facesEigenvalues.csv");
    for(unsigned i=0; i<l; i++) 
        ofs << pca.eigenvalue(i) << endl;
    exportPGM("facesMean.pgm", pca.mean(), x, y);
    cout << "done. " << endl;
 
    cout << "Encoding ... " << flush;
    unsigned m = 299;
    LinearModel<> enc;
    pca.encoder(enc, m);
    Data<RealVector> encodedImages = enc(images);
    cout << "done. " << endl;
 
    unsigned sampleImage = 0;
    cout << "Reconstructing face " << sampleImage << " ... " << flush;
    boost::format fmterTrue("face%d.pgm");
    exportPGM((fmterTrue % sampleImage).str().c_str(), images.element(sampleImage), x, y);
    LinearModel<> dec;
    pca.decoder(dec, m);
    boost::format fmterRec("facesReconstruction%d-%d.pgm");
    exportPGM((fmterRec % sampleImage % m).str().c_str(), dec(encodedImages.element(sampleImage)), x, y);
    cout << "done." << endl;
}