Visual Servoing Platform  version 3.2.0 under development (2018-10-15)
homographyRansac2DObject.cpp

Example of the Ransac homography estimation algorithm using vpHomography class.

/****************************************************************************
*
* This file is part of the ViSP software.
* Copyright (C) 2005 - 2017 by Inria. All rights reserved.
*
* This software is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
* See the file LICENSE.txt at the root directory of this source
* distribution for additional information about the GNU GPL.
*
* For using ViSP with software that can not be combined with the GNU
* GPL, please contact Inria about acquiring a ViSP Professional
* Edition License.
*
* See http://visp.inria.fr for more information.
*
* This software was developed at:
* Inria Rennes - Bretagne Atlantique
* Campus Universitaire de Beaulieu
* 35042 Rennes Cedex
* France
*
* If you have questions regarding the use of this file, please contact
* Inria at visp@inria.fr
*
* This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
* WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*
* Description:
* Example of the Ransac homography estimation algorithm.
*
* Authors:
* Eric Marchand
*
*****************************************************************************/
#include <visp3/core/vpDebug.h>
#include <visp3/core/vpMath.h>
#include <visp3/core/vpRotationMatrix.h>
#include <visp3/core/vpThetaUVector.h>
#include <visp3/vision/vpHomography.h>
#include <visp3/core/vpDebug.h>
#include <visp3/core/vpHomogeneousMatrix.h>
#include <visp3/core/vpMath.h>
#include <visp3/core/vpPoint.h>
#include <stdlib.h>
#include <visp3/core/vpRansac.h>
#include <visp3/io/vpParseArgv.h>
// List of allowed command line options
#define GETOPTARGS "h"
void usage(const char *name, const char *badparam);
bool getOptions(int argc, const char **argv);
void usage(const char *name, const char *badparam)
{
fprintf(stdout, "\n\
Test the Ransac homography estimation algorithm.\n\
\n\
SYNOPSIS\n\
%s [-h]\n", name);
fprintf(stdout, "\n\
OPTIONS: Default\n\
-h\n\
Print the help.\n");
if (badparam) {
fprintf(stderr, "ERROR: \n");
fprintf(stderr, "\nBad parameter [%s]\n", badparam);
}
}
bool getOptions(int argc, const char **argv)
{
const char *optarg_;
int c;
while ((c = vpParseArgv::parse(argc, argv, GETOPTARGS, &optarg_)) > 1) {
switch (c) {
case 'h':
usage(argv[0], NULL);
return false;
break;
default:
usage(argv[0], optarg_);
return false;
break;
}
}
if ((c == 1) || (c == -1)) {
// standalone param or error
usage(argv[0], NULL);
std::cerr << "ERROR: " << std::endl;
std::cerr << " Bad argument " << optarg_ << std::endl << std::endl;
return false;
}
return true;
}
int main(int argc, const char **argv)
{
try {
// Read the command line options
if (getOptions(argc, argv) == false) {
exit(-1);
}
double L = 0.1;
unsigned int nbpt = 11;
std::vector<vpPoint> P(nbpt); // Point to be tracked
std::vector<double> xa(nbpt), ya(nbpt), xb(nbpt), yb(nbpt);
P[0].setWorldCoordinates(-L, -L, 0); // inlier
P[1].setWorldCoordinates(2 * L, -L, 0); // inlier
P[2].setWorldCoordinates(L, L, 0); // inlier
P[3].setWorldCoordinates(-L, 3 * L, 0); // inlier
P[4].setWorldCoordinates(0, 0, L);
P[5].setWorldCoordinates(L, -2 * L, L);
P[6].setWorldCoordinates(L, -4 * L, 2 * L);
P[7].setWorldCoordinates(-2 * L, -L, -3 * L);
P[8].setWorldCoordinates(-5 * L, -5 * L, 0); // inlier
P[9].setWorldCoordinates(-2 * L, +3 * L, 4 * L);
P[10].setWorldCoordinates(-2 * L, -0.5 * L, 0); // inlier
std::vector<bool> inliers_ground_truth(nbpt, false);
inliers_ground_truth[0] = true;
inliers_ground_truth[1] = true;
inliers_ground_truth[2] = true;
inliers_ground_truth[3] = true;
inliers_ground_truth[8] = true;
inliers_ground_truth[10] = true;
vpHomogeneousMatrix bMo(0, 0, 1, 0, 0, 0);
vpHomogeneousMatrix aMb(0.1, 0.1, 0.1, vpMath::rad(10), 0, vpMath::rad(40));
vpHomogeneousMatrix aMo = aMb * bMo;
for (unsigned int i = 0; i < nbpt; i++) {
P[i].project(aMo);
xa[i] = P[i].get_x();
ya[i] = P[i].get_y();
}
for (unsigned int i = 0; i < nbpt; i++) {
P[i].project(bMo);
xb[i] = P[i].get_x();
yb[i] = P[i].get_y();
}
std::cout << "-------------------------------" << std::endl;
std::cout << "Compare with built homography H = R + t/d n " << std::endl;
vpPlane bp(0, 0, 1, 1);
vpHomography aHb_built(aMb, bp);
std::cout << "aHb built from the displacement: \n" << aHb_built / aHb_built[2][2] << std::endl;
aHb_built.computeDisplacement(aRb, aTb, n);
std::cout << "Rotation aRb: " << std::endl;
std::cout << aRb << std::endl;
std::cout << "Translation: aTb" << std::endl;
std::cout << (aTb).t() << std::endl;
std::cout << "Normal to the plane: n" << std::endl;
std::cout << (n).t() << std::endl;
std::cout << "-------------------------------" << std::endl;
std::vector<bool> inliers;
double residual;
// Suppose px=1000. Set the threshold to 2 pixels => 2/1000
// In the data we have 6 inliers. We request that at least 6 are retrieved
vpHomography::ransac(xb, yb, xa, ya, aHb, inliers, residual, 6, 2. / 1000);
std::cout << "aHb estimated using ransac:\n" << aHb << std::endl;
std::cout << "Inliers indexes (should be 0,1,2,3,8,10): ";
for (unsigned int i = 0; i < inliers.size(); i++)
if (inliers[i])
std::cout << i << ",";
std::cout << std::endl;
if (inliers == inliers_ground_truth) {
std::cout << "Ransac estimation succeed" << std::endl;
return EXIT_SUCCESS;
} else {
std::cout << "Ransac estimation fails" << std::endl;
return EXIT_FAILURE;
}
} catch (const vpException &e) {
std::cout << "Catch an exception: " << e << std::endl;
return EXIT_FAILURE;
}
}