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.camera; 31 32 import org.openimaj.math.geometry.point.Point2d; 33 import org.openimaj.math.geometry.point.Point2dImpl; 34 import org.openimaj.math.geometry.point.Point3d; 35 import org.openimaj.math.matrix.MatrixUtils; 36 37 import Jama.Matrix; 38 39 /** 40 * A model of the extrinsic parameters of a pinhole (projective) camera 41 * (translation in 3d space, and 3d rotation matrix), coupled with the camera's 42 * intrinsic parameters. 43 * 44 * @author Jonathon Hare (jsh2@ecs.soton.ac.uk) 45 */ 46 public class Camera { 47 /** 48 * The intrinsic parameters of this camera 49 */ 50 public CameraIntrinsics intrinsicParameters; 51 52 /** 53 * The rotation of this camera in world coordinates 54 */ 55 public Matrix rotation; 56 57 /** 58 * The position of this camera in world coordinates 59 */ 60 public Point3d translation; 61 62 /** 63 * Compute the homography of this camera to the z=0 plane based on it's 64 * parameters: H = KA, where A = [r1 r2 t] and r1 and r2 are the first and 65 * second columns of the rotation matrix, and K is the calibration matrix. 66 * 67 * @return the camera's homography 68 */ 69 public Matrix computeHomography() { 70 final Matrix A = rotation.copy(); 71 A.set(0, 2, translation.getX()); 72 A.set(1, 2, translation.getY()); 73 A.set(2, 2, translation.getZ()); 74 75 final Matrix H = intrinsicParameters.calibrationMatrix.times(A); 76 MatrixUtils.times(H, 1.0 / H.get(2, 2)); 77 78 return H; 79 } 80 81 /** 82 * Project a 2d point (technically a 3d point on the z=0 world plane) 83 * 84 * @param pt 85 * the point to project in world coordinates 86 * @return the image coordinates 87 */ 88 public Point2d project(Point2d pt) { 89 final Matrix H = this.computeHomography(); 90 91 final Point2d p = pt.transform(H); 92 93 return intrinsicParameters.applyDistortion(p); 94 } 95 96 /** 97 * Project a 3d point onto the image plane 98 * 99 * @param pt 100 * the point to project in world coordinates 101 * @return the image coordinates 102 */ 103 public Point2d project(Point3d pt) { 104 final Matrix ptm = new Matrix(new double[][] { { pt.getX() }, { pt.getY() }, { pt.getZ() }, { 1 } }); 105 final double[][] rv = rotation.getArray(); 106 final Matrix Rt = new Matrix(new double[][] { 107 { rv[0][0], rv[0][1], rv[0][2], translation.getX() }, 108 { rv[1][0], rv[1][1], rv[1][2], translation.getY() }, 109 { rv[2][0], rv[2][1], rv[2][2], translation.getZ() }, 110 }); 111 final Matrix ARt = intrinsicParameters.calibrationMatrix.times(Rt); 112 113 final Matrix pr = ARt.times(ptm); 114 115 final Point2dImpl p = new Point2dImpl(pr.get(0, 0) / pr.get(2, 0), pr.get(1, 0) / pr.get(2, 0)); 116 117 return intrinsicParameters.applyDistortion(p); 118 } 119 }