1 /** 2 * Copyright (c) 2011, The University of Southampton and the individual contributors. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without modification, 6 * are permitted provided that the following conditions are met: 7 * 8 * * Redistributions of source code must retain the above copyright notice, 9 * this list of conditions and the following disclaimer. 10 * 11 * * Redistributions in binary form must reproduce the above copyright notice, 12 * this list of conditions and the following disclaimer in the documentation 13 * and/or other materials provided with the distribution. 14 * 15 * * Neither the name of the University of Southampton nor the names of its 16 * contributors may be used to endorse or promote products derived from this 17 * software without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 21 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 22 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR 23 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 24 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 25 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON 26 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 28 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 */ 30 package org.openimaj.image.feature.global; 31 32 import org.openimaj.citation.annotation.Reference; 33 import org.openimaj.citation.annotation.ReferenceType; 34 import org.openimaj.feature.DoubleFV; 35 import org.openimaj.feature.FeatureVectorProvider; 36 import org.openimaj.image.FImage; 37 import org.openimaj.image.analyser.ImageAnalyser; 38 39 /** 40 * Implementation of the RMS contrast feature. 41 * <p> 42 * See the referenced paper for a description. 43 * 44 * @author Jonathon Hare (jsh2@ecs.soton.ac.uk) 45 */ 46 @Reference( 47 type = ReferenceType.Inproceedings, 48 author = { "Jose San Pedro", "Stefan Siersdorfer" }, 49 title = "Ranking and Classifying Attractiveness of Photos in Folksonomies", 50 year = "2009", 51 booktitle = "18th International World Wide Web Conference", 52 pages = { "771", "", "771" }, 53 url = "http://www2009.eprints.org/78/", 54 month = "April") 55 public class RMSContrast implements ImageAnalyser<FImage>, FeatureVectorProvider<DoubleFV> { 56 double contrast; 57 58 @Override 59 public DoubleFV getFeatureVector() { 60 return new DoubleFV(new double[] { contrast }); 61 } 62 63 /* 64 * (non-Javadoc) 65 * 66 * @see 67 * org.openimaj.image.processor.ImageProcessor#processImage(org.openimaj 68 * .image.Image) 69 */ 70 @Override 71 public void analyseImage(FImage image) { 72 final int width = image.width; 73 final int height = image.height; 74 75 double avg = 0; 76 for (int y = 0; y < height; y++) 77 for (int x = 0; x < width; x++) 78 avg += image.pixels[y][x]; 79 avg /= (width * height); 80 81 contrast = 0; 82 for (int y = 0; y < height; y++) { 83 for (int x = 0; x < width; x++) { 84 final double delta = image.pixels[y][x] - avg; 85 contrast += delta * delta; 86 } 87 } 88 89 contrast /= ((height * width) - 1); 90 } 91 92 /** 93 * Get the contrast of the last image analysed with 94 * {@link #analyseImage(FImage)} 95 * 96 * @return the contrast 97 */ 98 public double getContrast() { 99 return contrast; 100 } 101 }