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 Weber 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 = { "Che-Hua Yeh", "Yuan-Chen Ho", "Brian A. Barsky", "Ming Ouhyoung" },
49 title = "Personalized Photograph Ranking and Selection System",
50 year = "2010",
51 booktitle = "Proceedings of ACM Multimedia",
52 pages = { "211", "220" },
53 month = "October",
54 customData = { "location", "Florence, Italy" })
55 public class WeberContrast 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 double avg = 0;
75
76 for (int y = 0; y < height; y++)
77 for (int x = 0; x < width; x++)
78 avg += image.pixels[y][x];
79
80 avg /= (width * height);
81
82 contrast = 0;
83 for (int y = 0; y < height; y++)
84 for (int x = 0; x < width; x++)
85 contrast += (image.pixels[y][x] - avg) / avg;
86
87 contrast /= (height * width);
88 }
89
90 /**
91 * Get the contrast of the last image analysed with
92 * {@link #analyseImage(FImage)}
93 *
94 * @return the contrast
95 */
96 public double getContrast() {
97 return contrast;
98 }
99 }