Visual Servoing Platform  version 3.5.0 under development (2022-02-15)
homographyHartleyDLT2DObject.cpp

Example of the HartleyDLT homography estimation algorithm using vpHomography class.

/****************************************************************************
*
* ViSP, open source Visual Servoing Platform software.
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* Campus Universitaire de Beaulieu
* 35042 Rennes Cedex
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*
* Description:
* Example of the HartleyDLT 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 <stdlib.h>
#include <visp3/core/vpDebug.h>
#include <visp3/core/vpHomogeneousMatrix.h>
#include <visp3/core/vpMath.h>
#include <visp3/core/vpPoint.h>
#include <visp3/io/vpParseArgv.h>
// List of allowed command line options
#define GETOPTARGS "h"
#define L 0.1
#define nbpt 5
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 HartleyDLT 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)
{
#if (defined(VISP_HAVE_LAPACK) || defined(VISP_HAVE_EIGEN3) || defined(VISP_HAVE_OPENCV))
try {
// Read the command line options
if (getOptions(argc, argv) == false) {
exit(-1);
}
vpPoint P[nbpt]; // Point to be tracked
std::vector<double> xa(nbpt), ya(nbpt), xb(nbpt), yb(nbpt);
vpPoint aP[nbpt]; // Point to be tracked
vpPoint bP[nbpt]; // Point to be tracked
P[0].setWorldCoordinates(-L, -L, 0);
P[1].setWorldCoordinates(2 * L, -L, 0);
P[2].setWorldCoordinates(L, L, 0);
P[3].setWorldCoordinates(-L, 3 * L, 0);
P[4].setWorldCoordinates(0, 0, 0);
/*
P[5].setWorldCoordinates(10,20, 0 ) ;
P[6].setWorldCoordinates(-10,12, 0 ) ;
*/
vpHomogeneousMatrix bMo(0, 0, 1, 0, 0, 0);
vpHomogeneousMatrix aMb(1, 0, 0.0, vpMath::rad(10), 0, vpMath::rad(40));
vpHomogeneousMatrix aMo = aMb * bMo;
for (unsigned int i = 0; i < nbpt; i++) {
P[i].project(aMo);
aP[i] = P[i];
xa[i] = P[i].get_x();
ya[i] = P[i].get_y();
}
for (unsigned int i = 0; i < nbpt; i++) {
P[i].project(bMo);
bP[i] = P[i];
xb[i] = P[i].get_x();
yb[i] = P[i].get_y();
}
std::cout << "-------------------------------" << std::endl;
std::cout << "aMb " << std::endl << aMb << std::endl;
std::cout << "-------------------------------" << std::endl;
vpHomography::DLT(xb, yb, xa, ya, aHb, true);
vpTRACE("aHb computed using the DLT algorithm");
aHb /= aHb[2][2];
std::cout << std::endl << aHb << std::endl;
std::cout << "-------------------------------" << std::endl;
vpTRACE("extract R, T and n ");
aHb.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;
vpTRACE("Compare with built homoraphy H = R + t/d ");
vpPlane bp(0, 0, 1, 1);
vpHomography aHb_built(aMb, bp);
vpTRACE("aHb built from the displacement ");
std::cout << std::endl << 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;
vpTRACE("test if ap = aHb bp");
for (unsigned int i = 0; i < nbpt; i++) {
std::cout << "Point " << i << std::endl;
std::cout << "(";
std::cout << aP[i].get_x() / aP[i].get_w() << ", " << aP[i].get_y() / aP[i].get_w();
std::cout << ") = (";
p = aHb * bP[i];
std::cout << p.get_x() / p.get_w() << ", " << p.get_y() / p.get_w() << ")" << std::endl;
}
return EXIT_SUCCESS;
} catch (const vpException &e) {
std::cout << "Catch an exception: " << e << std::endl;
return EXIT_FAILURE;
}
#else
(void)argc;
(void)argv;
std::cout << "Cannot run this example: install Lapack, Eigen3 or OpenCV" << std::endl;
return EXIT_SUCCESS;
#endif
}