001/*******************************************************************************
002 * This software is provided as a supplement to the authors' textbooks on digital
003 * image processing published by Springer-Verlag in various languages and editions.
004 * Permission to use and distribute this software is granted under the BSD 2-Clause
005 * "Simplified" License (see http://opensource.org/licenses/BSD-2-Clause).
006 * Copyright (c) 2006-2023 Wilhelm Burger, Mark J. Burge. All rights reserved.
007 * Visit https://imagingbook.com for additional details.
008 ******************************************************************************/
009package Ch03_Point_Operations;
010
011import ij.IJ;
012import ij.ImagePlus;
013import ij.gui.GenericDialog;
014import ij.plugin.filter.PlugInFilter;
015import ij.process.ImageProcessor;
016import imagingbook.common.histogram.HistogramPlot;
017import imagingbook.common.histogram.HistogramUtils;
018import imagingbook.common.ij.DialogUtils;
019import imagingbook.core.jdoc.JavaDocHelp;
020import imagingbook.sampleimages.GeneralSampleImage;
021
022import static imagingbook.common.ij.IjUtils.noCurrentImage;
023import static imagingbook.common.math.Arithmetic.sqr;
024
025/**
026 * <p>
027 * ImageJ plugin, adapts image intensities to match a Gaussian distribution with specified parameters &mu;, &sigma;
028 * ({@link #Mean}, {@link #StdDev}). The current active image is modified, the histogram and cumulative histogram of the
029 * resulting image are displayed. See Sec. 3.6.4 (Fig. 3.15) of [1] for additional details.
030 * </p>
031 * <p>
032 * [1] W. Burger, M.J. Burge, <em>Digital Image Processing &ndash; An Algorithmic Introduction</em>, 3rd ed, Springer
033 * (2022).
034 * </p>
035 *
036 * @author WB
037 * @see HistogramUtils
038 * @see HistogramPlot
039 */
040public class Match_Gaussian_Histogram implements PlugInFilter, JavaDocHelp {
041
042        // parameters of Gaussian target distribution:
043        private static double Mean = 128;
044        private static double StdDev = 90;
045
046        private static boolean ShowOriginalHistograms = true;
047        private static boolean ShowCumulativeHistograms = true;
048        private static boolean ShowFinalHistogram = true;
049        private static boolean ListMappingFunction = false;
050
051        /** Constructor, asks to open a predefined sample image if no other image is currently open. */
052        public Match_Gaussian_Histogram() {
053                if (noCurrentImage()) {
054                        DialogUtils.askForSampleImage(GeneralSampleImage.IrishManor);
055                }
056        }
057        
058        @Override
059        public int setup(String arg0, ImagePlus im) {
060                return DOES_8G;
061        }
062        
063        @Override
064        public void run(ImageProcessor ip) {
065                if (!runDialog()) {
066                        return;
067                }
068                
069                // get histograms
070                int[] hi = ip.getHistogram();
071                int[] hG = makeGaussianHistogram(Mean, StdDev);
072
073                if (ShowOriginalHistograms) {
074                        new HistogramPlot(hi, "Original Histogram").show();
075                        new HistogramPlot(hG, "Gaussian Histogram").show();
076                }
077                
078                double[] chG = HistogramUtils.cdf(hG);
079        int[] F = HistogramUtils.matchHistograms(hi, hG);
080                ip.applyTable(F);
081                int[] hAm = ip.getHistogram();
082
083                if (ShowFinalHistogram) {
084                        new HistogramPlot(hAm, "Final Histogram").show();
085                }
086
087                if (ShowCumulativeHistograms) {
088                        new HistogramPlot(chG, "Gaussian Cumulative Histogram").show();
089                        new HistogramPlot(HistogramUtils.cdf(hAm), "Final Cumulative Histogram").show();
090                }
091
092                if (ListMappingFunction) {
093                        for (int i = 0; i < F.length; i++) {
094                                IJ.log(i + " -> " + F[i]);
095                        }
096                }
097        }
098        
099        private int[] makeGaussianHistogram (double mean, double sigma) {
100                int[] h = new int[256];
101                double sigma2 = 2 * sqr(sigma);
102                for (int i = 0; i < h.length; i++) {
103                        double x = mean - i;
104                        double g = Math.exp(-sqr(x) / sigma2) / sigma;
105                        h[i] = (int) Math.round(10000 * g);
106                }
107                return h;
108        }
109
110        private boolean runDialog() {
111                GenericDialog gd = new GenericDialog(this.getClass().getSimpleName());
112                gd.addHelp(getJavaDocUrl());
113                gd.addNumericField("Mean (μ)", Mean, 2);
114                gd.addNumericField("Std deviation (σ)", StdDev, 2);
115
116                gd.addCheckbox("Show original histograms", ShowOriginalHistograms);
117                gd.addCheckbox("Show cumulative histograms", ShowCumulativeHistograms);
118                gd.addCheckbox("Show final histogram", ShowFinalHistogram);
119                gd.addCheckbox("List mapping function", ListMappingFunction);
120
121                gd.showDialog();
122                if(gd.wasCanceled())
123                        return false;
124
125                Mean = gd.getNextNumber();
126                StdDev = gd.getNextNumber();
127
128                ShowOriginalHistograms = gd.getNextBoolean();
129                ShowCumulativeHistograms = gd.getNextBoolean();
130                ShowFinalHistogram = gd.getNextBoolean();
131                ListMappingFunction = gd.getNextBoolean();
132                return true;
133        }
134
135}
136