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 Ch21_Geometric_Operations;
010
011import ij.IJ;
012import ij.ImagePlus;
013import ij.plugin.filter.PlugInFilter;
014import ij.process.ImageProcessor;
015import imagingbook.common.geometry.basic.Pnt2d;
016import imagingbook.common.geometry.mappings.linear.LinearMapping2D;
017import imagingbook.common.geometry.mappings.linear.ProjectiveMapping2D;
018import imagingbook.common.ij.DialogUtils;
019import imagingbook.common.ij.IjUtils;
020import imagingbook.common.image.ImageMapper;
021import imagingbook.common.image.OutOfBoundsStrategy;
022import imagingbook.common.image.interpolation.InterpolationMethod;
023import imagingbook.common.math.Matrix;
024import imagingbook.core.jdoc.JavaDocHelp;
025import imagingbook.sampleimages.GeneralSampleImage;
026
027/**
028 * <p>
029 * This plugin demonstrates the use of geometric mappings, as implemented in the imagingbook library. A
030 * {@link ProjectiveMapping2D} (transformation) is specified by 4 corresponding point pairs, given by point sequences P
031 * and Q. The inverse mapping is required for target-to-source mapping. See Sec. 21.1.4 of [1] for details. The actual
032 * pixel transformation is performed by an {@link ImageMapper} object. Try on a suitable test image and check if the
033 * image corners (P) are mapped to the points specified in Q. This plugin works for all image types. The transformed
034 * image is shown in a new window, the original image remains unchanged. Optionally opens a sample image if no image is
035 * currently open.
036 * </p>
037 * <p>
038 * [1] W. Burger, M.J. Burge, <em>Digital Image Processing &ndash; An Algorithmic Introduction</em>, 3rd ed, Springer
039 * (2022).
040 * </p>
041 *
042 * @author WB
043 * @version 2022/11/28
044 * @see LinearMapping2D
045 * @see ProjectiveMapping2D
046 * @see ImageMapper
047 */
048public class Map_Projective implements PlugInFilter, JavaDocHelp {
049        
050        private static Pnt2d[] P = {            // source quad
051                        Pnt2d.from(0, 0),
052                        Pnt2d.from(400, 0),
053                        Pnt2d.from(400, 400),
054                        Pnt2d.from(0, 400)};
055
056        private static Pnt2d[] Q = {            // target quad
057                        Pnt2d.from(0, 60),
058                        Pnt2d.from(400, 20),
059                        Pnt2d.from(300, 400),
060                        Pnt2d.from(30, 200)};
061
062        private ImagePlus im;
063        
064        /**
065         * Constructor, asks to open a predefined sample image if no other image
066         * is currently open.
067         */
068        public Map_Projective() {
069                if (IjUtils.noCurrentImage()) {
070                        DialogUtils.askForSampleImage(GeneralSampleImage.Kepler);
071                }
072        }
073        
074        @Override
075        public int setup(String arg, ImagePlus im) {
076                this.im = im;
077                return DOES_ALL + NO_CHANGES;
078        }
079
080        @Override
081        public void run(ImageProcessor source) {
082                int W = source.getWidth();
083                int H = source.getHeight();
084                
085                // create the target image:
086                ImageProcessor target = source.createProcessor(W, H); 
087                
088                // create the target-to source mapping, i.e. Q -> P. 
089                // there are 2 alternatives:
090                LinearMapping2D m = ProjectiveMapping2D.fromPoints(P, Q);               // P -> Q, then invert
091                LinearMapping2D mi = m.getInverse();            
092                //Mapping2D mi = ProjectiveMapping2D.fromPoints(Q, P);  // Q -> P = inverse mapping
093
094                // create a mapper instance:
095                ImageMapper mapper = 
096                                new ImageMapper(mi, OutOfBoundsStrategy.ZeroValues, InterpolationMethod.Bicubic);
097                
098                // apply the mapper:
099                mapper.map(source, target);
100                
101                // display the target image:
102                new ImagePlus(im.getShortTitle() + "-transformed", target).show();
103                
104                IJ.log("A = \n" + Matrix.toString(m.getTransformationMatrix()));
105        }
106}