edu.stanford.rsl.conrad.segmentation.PolynomialMultiChannelGridFeatureExtractor.java Source code

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Here is the source code for edu.stanford.rsl.conrad.segmentation.PolynomialMultiChannelGridFeatureExtractor.java

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/*
 * Copyright (C) 2017 Andreas Maier
 * CONRAD is developed as an Open Source project under the GNU General Public License (GPL).
 */
package edu.stanford.rsl.conrad.segmentation;

import java.util.ArrayList;

import edu.stanford.rsl.conrad.data.numeric.MultiChannelGrid2D;
import edu.stanford.rsl.conrad.utils.UserUtil;
import weka.core.Attribute;
import weka.core.Instances;
import weka.core.Utils;

public class PolynomialMultiChannelGridFeatureExtractor extends MultiChannelGridFeatureExtractor {

    /**
     * 
     */
    private static final long serialVersionUID = -1119850657741445026L;
    int polydegree = 3;

    @Override
    public void configure() throws Exception {
        polydegree = UserUtil.queryInt("Enter degree of polynomial transformation:", polydegree);
        multiChannelGrid = (MultiChannelGrid2D) dataGrid;
        int numFeatures = multiChannelGrid.getNumberOfChannels();
        attribs = new ArrayList<Attribute>(numFeatures + 1);
        int combinations = (int) Math.pow(polydegree + 1, numFeatures);
        int[] index = new int[numFeatures];
        for (int i = 1; i < combinations; i++) {
            int current = i;
            String indexString = "";
            for (int j = 0; j < numFeatures; j++) {
                index[j] = current % (polydegree + 1);
                current /= (polydegree + 1);
                indexString += " " + index[j];
            }
            String nameString = "Feature " + i + " degree " + indexString;
            attribs.add(new weka.core.Attribute(nameString));
        }
        Attribute classAttribute = generateClassAttribute();
        attribs.add(classAttribute);
        instances = new Instances(className, attribs, 0);
        instances.setClass(classAttribute);
        configured = true;
    }

    @Override
    public double[] extractFeatureAtIndex(int x, int y) {
        int numFeatures = multiChannelGrid.getNumberOfChannels();
        double attValues[] = new double[attribs.size()];
        attValues[attribs.size() - 1] = labelGrid.getPixelValue(x, y);
        int combinations = (int) Math.pow(polydegree + 1, numFeatures);
        int[] index = new int[numFeatures];
        for (int count = 1; count < combinations; count++) {
            int current = count;
            double value = 1.0;
            for (int feat = 0; feat < numFeatures; feat++) {
                index[feat] = current % (polydegree + 1);
                current /= (polydegree + 1);
                double fromImage = multiChannelGrid.getChannel(feat).getPixelValue(x, y);
                value *= Math.pow(fromImage, index[feat]);
            }
            attValues[count - 1] = value;
            if (Double.isInfinite(value)) {
                attValues[count - 1] = Utils.missingValue();
            }
        }
        return attValues;
    }

    /**
     * @return the polydegree
     */
    public int getPolydegree() {
        return polydegree;
    }

    /**
     * @param polydegree the polydegree to set
     */
    public void setPolydegree(int polydegree) {
        this.polydegree = polydegree;
    }

    public String getName() {
        return "Polynomial Combination of Channels as Features";
    }

}