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.feature.local.matcher;
031
032import java.util.ArrayList;
033import java.util.List;
034
035import org.openimaj.image.feature.local.keypoints.Keypoint;
036import org.openimaj.util.pair.Pair;
037
038
039/**
040 * Basic keypoint matcher. Matches keypoints by finding closest
041 * Two keypoints to target and checking whether the distance
042 * between the two matches is sufficiently large.
043 * 
044 * @author Jonathon Hare
045 * @param <T> Keypoint type
046 *
047 */
048public class FastLimitedBasicKeypointMatcher<T extends Keypoint> extends FastBasicKeypointMatcher<T> {
049        private int limit;
050
051        /**
052         * 
053         * @param threshold threshold for determining matching keypoints
054         * @param limit
055         */
056        public FastLimitedBasicKeypointMatcher(int threshold, int limit)
057        {
058                super(threshold);
059                this.limit = limit;
060        }
061        
062        @Override
063        public boolean findMatches(List<T> keys1)
064        {
065                matches = new ArrayList<Pair<T>>();
066                
067                byte [][] data = new byte[keys1.size()][];
068                for (int i=0; i<keys1.size(); i++)
069                        data[i] = keys1.get(i).ivec;
070                
071                int [][] argmins = new int[keys1.size()][2];
072                float [][] mins = new float[keys1.size()][2];
073                modelKeypointsKNN.searchKNN(data, 2, argmins, mins);
074                
075                for (int i=0; i<keys1.size(); i++) {
076                        float distsq1 = mins[i][0];
077                        float distsq2 = mins[i][1];
078                        
079                        if (10 * 10 * distsq1 < thresh * thresh * distsq2) {
080                                matches.add(new Pair<T>(keys1.get(i), modelKeypoints.get(argmins[i][0])));
081                    }
082                        
083                        if (matches.size() >= limit) break;
084                }
085                
086            return true;
087        }
088}