001/**
002 * Copyright (c) 2011, The University of Southampton and the individual contributors.
003 * All rights reserved.
004 *
005 * Redistribution and use in source and binary forms, with or without modification,
006 * are permitted provided that the following conditions are met:
007 *
008 *   *  Redistributions of source code must retain the above copyright notice,
009 *      this list of conditions and the following disclaimer.
010 *
011 *   *  Redistributions in binary form must reproduce the above copyright notice,
012 *      this list of conditions and the following disclaimer in the documentation
013 *      and/or other materials provided with the distribution.
014 *
015 *   *  Neither the name of the University of Southampton nor the names of its
016 *      contributors may be used to endorse or promote products derived from this
017 *      software without specific prior written permission.
018 *
019 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
020 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
021 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
022 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
023 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
024 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
025 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
026 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
027 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
028 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
029 */
030package org.openimaj.image.analysis.algorithm.histogram.binning;
031
032import java.util.List;
033
034import org.openimaj.image.analysis.algorithm.histogram.WindowedHistogramExtractor;
035import org.openimaj.image.pixel.sampling.QuadtreeSampler;
036import org.openimaj.math.geometry.shape.Rectangle;
037import org.openimaj.math.statistics.distribution.Histogram;
038
039/**
040 * A {@link SpatialBinningStrategy} that extracts histograms from regions
041 * defined by a fixed depth quadtree overlayed over the sampling region and
042 * concatenates them together.
043 * 
044 * @author Jonathon Hare (jsh2@ecs.soton.ac.uk)
045 */
046public class QuadtreeStrategy implements SpatialBinningStrategy {
047        int nlevels;
048
049        /**
050         * Construct with the given quadtree depth
051         * 
052         * @param nlevels
053         *            quadtree depth
054         */
055        public QuadtreeStrategy(int nlevels) {
056                this.nlevels = nlevels;
057        }
058
059        @Override
060        public Histogram extract(WindowedHistogramExtractor binnedData, Rectangle region, Histogram output) {
061                final QuadtreeSampler sampler = new QuadtreeSampler(region, nlevels);
062                final int blockSize = binnedData.getNumBins();
063                final List<Rectangle> rects = sampler.allRectangles();
064
065                if (output == null || output.values.length != blockSize * rects.size())
066                        output = new Histogram(blockSize * rects.size());
067
068                final Histogram tmp = new Histogram(blockSize);
069                for (int i = 0; i < rects.size(); i++) {
070                        final Rectangle r = rects.get(i);
071
072                        binnedData.computeHistogram(r, tmp);
073
074                        System.arraycopy(tmp.values, 0, output.values, blockSize * i, blockSize);
075                }
076
077                return output;
078        }
079}