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 }