001/** 002 * Copyright (c) 2011, The University of Southampton and the individual contributors. 003 * All rights reserved. 004 * 005 * Redistribution and use in source and binary forms, with or without modification, 006 * are permitted provided that the following conditions are met: 007 * 008 * * Redistributions of source code must retain the above copyright notice, 009 * this list of conditions and the following disclaimer. 010 * 011 * * Redistributions in binary form must reproduce the above copyright notice, 012 * this list of conditions and the following disclaimer in the documentation 013 * and/or other materials provided with the distribution. 014 * 015 * * Neither the name of the University of Southampton nor the names of its 016 * contributors may be used to endorse or promote products derived from this 017 * software without specific prior written permission. 018 * 019 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND 020 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 021 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 022 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR 023 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 024 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 025 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON 026 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 027 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 028 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 029 */ 030package org.openimaj.examples.image.analysis; 031 032import java.io.IOException; 033import java.net.URL; 034import java.util.ArrayList; 035import java.util.List; 036 037import org.openimaj.image.DisplayUtilities; 038import org.openimaj.image.FImage; 039import org.openimaj.image.ImageUtilities; 040import org.openimaj.image.MBFImage; 041import org.openimaj.image.analysis.algorithm.HoughLines; 042import org.openimaj.image.colour.RGBColour; 043import org.openimaj.image.processing.edges.CannyEdgeDetector; 044import org.openimaj.math.geometry.line.Line2d; 045import org.openimaj.math.geometry.line.Line2d.IntersectionResult; 046import org.openimaj.math.geometry.line.Line2d.IntersectionType; 047import org.openimaj.math.geometry.point.Point2d; 048 049/** 050 * Example showing how to find the corners of a chessboard pattern using a hough 051 * line detector. 052 * 053 * @author Sina Samangooei (ss@ecs.soton.ac.uk) 054 */ 055public class HoughLineChessboard { 056 /** 057 * Main method 058 * 059 * @param args 060 * ignored 061 * @throws IOException 062 * if image can't be loaded 063 */ 064 public static void main(String[] args) throws IOException { 065 final FImage chessboard = ImageUtilities.readF(new URL("http://www.ugcs.caltech.edu/~rajan/REPORT/camera.jpg")); 066 067 final HoughLines hlines = new HoughLines(1.f); 068 chessboard.process(new CannyEdgeDetector()).analyseWith(hlines); 069 070 final List<Line2d> lines = hlines.getBestLines(50); 071 final List<Point2d> intersections = new ArrayList<Point2d>(); 072 for (final Line2d inner : lines) { 073 for (final Line2d outer : lines) { 074 if (inner == outer) 075 continue; 076 077 final IntersectionResult intersect = inner.getIntersection(outer); 078 if (intersect.type == IntersectionType.INTERSECTING) { 079 intersections.add(intersect.intersectionPoint); 080 } 081 } 082 } 083 084 // draw result 085 final MBFImage chessboardC = chessboard.toRGB(); 086 chessboardC.drawLines(lines, 1, RGBColour.RED); 087 chessboardC.drawPoints(intersections, RGBColour.GREEN, 3); 088 089 DisplayUtilities.display(chessboardC); 090 } 091}