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package de.lmu.ifi.dbs.elki.distance.distancefunction.colorhistogram;
/*
This file is part of ELKI:
Environment for Developing KDD-Applications Supported by Index-Structures
Copyright (C) 2012
Ludwig-Maximilians-Universität München
Lehr- und Forschungseinheit für Datenbanksysteme
ELKI Development Team
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program 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 Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
import de.lmu.ifi.dbs.elki.distance.distancefunction.WeightedDistanceFunction;
import de.lmu.ifi.dbs.elki.math.linearalgebra.Matrix;
import de.lmu.ifi.dbs.elki.utilities.documentation.Reference;
import de.lmu.ifi.dbs.elki.utilities.optionhandling.AbstractParameterizer;
import de.lmu.ifi.dbs.elki.utilities.optionhandling.OptionID;
import de.lmu.ifi.dbs.elki.utilities.optionhandling.parameterization.Parameterization;
import de.lmu.ifi.dbs.elki.utilities.optionhandling.parameters.IntParameter;
/**
* Distance function for RGB color histograms based on a quadratic form and
* color similarity.
*
* This is (unverified) attributed to
* <p>
* James Hafner, Harpreet S.Sawhney, Will Equits, Myron Flickner and Wayne
* Niblack<br />
* Efficient Color Histogram Indexing for Quadratic Form Distance Functions<br />
* IEEE Trans. on Pattern Analysis and Machine Intelligence, Vol. 17, No. 7,
* July 1995
* </p>
*
* @author Erich Schubert
*/
@Reference(authors = "J. Hafner, H. S.Sawhney, W. Equits, M. Flickner, W. Niblack", title = "Efficient Color Histogram Indexing for Quadratic Form Distance Functions", booktitle = "IEEE Trans. on Pattern Analysis and Machine Intelligence, Vol. 17, No. 7, July 1995", url = "http://dx.doi.org/10.1109/34.391417")
public class RGBHistogramQuadraticDistanceFunction extends WeightedDistanceFunction {
/**
* Parameter for the kernel dimensionality.
*/
public static final OptionID BPP_ID = OptionID.getOrCreateOptionID("rgbhist.bpp", "The dimensionality of the histogram in each color");
/**
* Constructor.
*
* @param bpp bins per plane.
*/
public RGBHistogramQuadraticDistanceFunction(int bpp) {
super(computeWeightMatrix(bpp));
}
/**
* Compute weight matrix for a RGB color histogram
*
* @param bpp bins per plane
* @return Weight matrix
*/
public static Matrix computeWeightMatrix(int bpp) {
final int dim = bpp * bpp * bpp;
final Matrix m = new Matrix(dim, dim);
// maximum occurring distance in manhattan between bins:
final double max = 3. * (bpp - 1.);
for(int x = 0; x < dim; x++) {
final int rx = (x / bpp) / bpp;
final int gx = (x / bpp) % bpp;
final int bx = x % bpp;
for(int y = 0; y < dim; y++) {
final int ry = (y / bpp) / bpp;
final int gy = (y / bpp) % bpp;
final int by = y % bpp;
final double dr = Math.abs(rx - ry);
final double dg = Math.abs(gx - gy);
final double db = Math.abs(bx - by);
final double val = 1 - (dr + dg + db) / max;
m.set(x, y, val);
}
}
return m;
}
@Override
public boolean equals(Object obj) {
if(this == obj) {
return true;
}
if(obj == null) {
return false;
}
if (!this.getClass().equals(obj.getClass())) {
return false;
}
return this.weightMatrix.equals(((RGBHistogramQuadraticDistanceFunction)obj).weightMatrix);
}
/**
* Parameterization class.
*
* @author Erich Schubert
*
* @apiviz.exclude
*/
public static class Parameterizer extends AbstractParameterizer {
int bpp = 0;
@Override
protected void makeOptions(Parameterization config) {
super.makeOptions(config);
IntParameter param = new IntParameter(BPP_ID);
if(config.grab(param)) {
bpp = param.getValue();
}
}
@Override
protected RGBHistogramQuadraticDistanceFunction makeInstance() {
return new RGBHistogramQuadraticDistanceFunction(bpp);
}
}
}
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