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.segmentation;
031
032import gnu.trove.map.hash.TFloatObjectHashMap;
033
034import java.util.Arrays;
035import java.util.List;
036
037import org.openimaj.image.FImage;
038import org.openimaj.image.pixel.PixelSet;
039import org.openimaj.image.processor.Processor;
040
041/**
042 * Simple wrapper to make thresholding algorithms into {@link Segmenter}s by
043 * applying the thresholding operation and then gathering the pixel sets
044 * belonging to each segment. Note that class does not perform connected
045 * component analysis, and for example in the case of binary thresholding, there
046 * will only be two {@link PixelSet}s produced (i.e. foreground and background).
047 * 
048 * @author Jonathon Hare (jsh2@ecs.soton.ac.uk)
049 * 
050 */
051public class ThresholdSegmenter implements Segmenter<FImage> {
052        Processor<FImage> thresholder;
053
054        /**
055         * Construct with the given thresholding algorithm implementation.
056         * 
057         * @param thresholder
058         *            the thresholding algorithm
059         */
060        public ThresholdSegmenter(Processor<FImage> thresholder) {
061                this.thresholder = thresholder;
062        }
063
064        @Override
065        public List<? extends PixelSet> segment(FImage image) {
066                final FImage timg = image.process(thresholder);
067                final TFloatObjectHashMap<PixelSet> sets = new TFloatObjectHashMap<PixelSet>();
068
069                for (int y = 0; y < timg.height; y++) {
070                        for (int x = 0; x < timg.width; x++) {
071                                final float p = image.getPixel(x, y);
072
073                                PixelSet ps = sets.get(p);
074                                if (ps == null)
075                                        sets.put(p, ps = new PixelSet());
076                                ps.addPixel(x, y);
077                        }
078                }
079
080                return Arrays.asList(sets.values());
081        }
082}