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.processing.face.feature.ltp;
031
032import java.io.DataInput;
033import java.io.DataOutput;
034import java.io.IOException;
035
036import org.openimaj.citation.annotation.Reference;
037import org.openimaj.citation.annotation.ReferenceType;
038
039
040/**
041 * A truncated weighting scheme which cuts-off distances
042 * beyond a threshold.
043 * 
044 * @author Jonathon Hare (jsh2@ecs.soton.ac.uk)
045 *
046 */
047@Reference(
048                type = ReferenceType.Article,
049                author = { "Tan, Xiaoyang", "Triggs, Bill" },
050                title = "Enhanced local texture feature sets for face recognition under difficult lighting conditions",
051                year = "2010",
052                journal = "Trans. Img. Proc.",
053                pages = { "1635", "1650" },
054                url = "http://dx.doi.org/10.1109/TIP.2010.2042645",
055                month = "June",
056                number = "6",
057                publisher = "IEEE Press",
058                volume = "19"
059        )
060public class TruncatedWeighting implements LTPWeighting {
061        float threshold = 6;
062        
063        /**
064         * Construct with the default distance threshold of 6
065         */
066        public TruncatedWeighting() {}
067        
068        /**
069         * Construct with the given distance threshold.
070         * @param threshold the threshold.
071         */
072        public TruncatedWeighting(float threshold) {
073                this.threshold = threshold;
074        }
075        
076        @Override
077        public float weightDistance(float distance) {
078                return Math.min(distance, threshold);
079        }
080
081        @Override
082        public void readBinary(DataInput in) throws IOException {
083                threshold = in.readFloat();
084        }
085
086        @Override
087        public byte[] binaryHeader() {
088                return this.getClass().getName().getBytes();
089        }
090
091        @Override
092        public void writeBinary(DataOutput out) throws IOException {
093                out.writeFloat(threshold);
094        }
095        
096        @Override
097        public String toString() {
098                return "TruncatedWeighting[threshold="+threshold+"]";
099        }
100}