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.analysis.algorithm;
31
32 import org.openimaj.image.FImage;
33 import org.openimaj.image.analyser.ImageAnalyser;
34 import org.openimaj.math.util.Interpolation;
35
36 /**
37 * An {@link ImageAnalyser} that can provide interpolate pixel values using a
38 * variety of interpolation approaches.
39 *
40 * @author Jonathon Hare (jsh2@ecs.soton.ac.uk)
41 *
42 */
43 public class ImageInterpolation implements ImageAnalyser<FImage> {
44 /**
45 * Interface defining an object capable of performing pixel interpolation
46 *
47 * @author Jonathon Hare (jsh2@ecs.soton.ac.uk)
48 *
49 */
50 public static interface Interpolator {
51 /**
52 * Interpolate a pixel value
53 *
54 * @param x
55 * the x-ordinate
56 * @param y
57 * the y-ordinate
58 * @param image
59 * the image
60 * @param workingSpace
61 * the working space required
62 * @return the interpolated pixel value
63 */
64 public float interpolate(float x, float y, FImage image, Object workingSpace);
65
66 /**
67 * Create the working space required for interpolation
68 *
69 * @return the working space (can be <code>null</code>)
70 */
71 public Object createWorkingSpace();
72 }
73
74 /**
75 * Standard interpolation types.
76 *
77 * @author Jonathon Hare (jsh2@ecs.soton.ac.uk)
78 *
79 */
80 public static enum InterpolationType implements Interpolator {
81 /**
82 * Nearest neighbour interpolation
83 */
84 NEAREST_NEIGHBOUR {
85 @Override
86 public float interpolate(float x, float y, FImage image, Object workingSpace) {
87 x = Math.round(x);
88 y = Math.round(y);
89
90 if (x < 0 || x >= image.width || y < 0 || y >= image.height)
91 return 0;
92
93 return image.pixels[(int) y][(int) x];
94 }
95
96 @Override
97 public Object createWorkingSpace() {
98 return null;
99 }
100 },
101 /**
102 * Bilinear interpolation
103 */
104 BILINEAR {
105 @Override
106 public float interpolate(float x, float y, FImage image, Object workingSpace) {
107 return image.getPixelInterpNative(x, y, 0);
108 }
109
110 @Override
111 public Object createWorkingSpace() {
112 return null;
113 }
114 },
115 /**
116 * Bicubic interpolation
117 */
118 BICUBIC {
119 @Override
120 public float interpolate(float x, float y, FImage image, Object workingSpace) {
121 final float[][] working = (float[][]) workingSpace;
122
123 final int sx = (int) Math.floor(x) - 1;
124 final int sy = (int) Math.floor(y) - 1;
125 final int ex = sx + 3;
126 final int ey = sy + 3;
127
128 for (int yy = sy, i = 0; yy <= ey; yy++, i++) {
129 for (int xx = sx, j = 0; xx <= ex; xx++, j++) {
130 final int px = xx < 0 ? 0 : xx >= image.width ? image.width - 1 : xx;
131 final int py = yy < 0 ? 0 : yy >= image.height ? image.height - 1 : yy;
132
133 working[i][j] = image.pixels[py][px];
134 }
135 }
136
137 final float dx = (float) (x - Math.floor(x));
138 final float dy = (float) (y - Math.floor(y));
139 return Interpolation.bicubicInterp(dx, dy, working);
140 }
141
142 @Override
143 public Object createWorkingSpace() {
144 return new float[4][4];
145 }
146 };
147 }
148
149 protected Interpolator interpolator;
150 protected Object workingSpace;
151 protected FImage image;
152
153 /**
154 * Default constructor.
155 *
156 * @param interpolator
157 * the interpolator to use
158 */
159 public ImageInterpolation(Interpolator interpolator) {
160 this.interpolator = interpolator;
161 this.workingSpace = interpolator.createWorkingSpace();
162 }
163
164 @Override
165 public void analyseImage(FImage image) {
166 this.image = image;
167 }
168
169 /**
170 * Get the interpolated pixel value of the previously analysed image
171 *
172 * @param x
173 * the x-ordinate
174 * @param y
175 * the y-ordinate
176 * @return the interpolated pixel value
177 */
178 public float getPixelInterpolated(float x, float y) {
179 return interpolator.interpolate(x, y, image, workingSpace);
180 }
181 }