Visual Servoing Platform  version 3.3.1 under development (2020-09-18)
calibrate-hand-eye.cpp

Example of hand-eye calibration to estimate extrinsic camera parameters, ie hand-eye homogeneous transformation corresponding to the transformation between the robot end-effector and the camera.

/****************************************************************************
*
* ViSP, open source Visual Servoing Platform software.
* Copyright (C) 2005 - 2019 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:
* Hand-eye calibration example to estimate hand to eye transformation.
*
* Authors:
* Fabien Spindler
*
*****************************************************************************/
#include <iomanip>
#include <sstream>
#include <stdio.h>
#include <vector>
#include <visp3/core/vpDebug.h>
#include <visp3/core/vpExponentialMap.h>
#include <visp3/core/vpIoTools.h>
#include <visp3/io/vpParseArgv.h>
#include <visp3/vision/vpHandEyeCalibration.h>
int main()
{
#if (defined(VISP_HAVE_LAPACK) || defined(VISP_HAVE_EIGEN3) || defined(VISP_HAVE_OPENCV))
try {
// We want to calibrate the hand-eye extrinsic camera parameters from 6
// couple of poses: cMo and wMe
const unsigned int N = 6;
// Input: six couple of poses used as input in the calibration proces
std::vector<vpHomogeneousMatrix> cMo(N); // eye (camera) to object
// transformation. The object
// frame is attached to the
// calibrartion grid
std::vector<vpHomogeneousMatrix> wMe(N); // world to hand (end-effector) transformation
// Output: Result of the calibration
vpHomogeneousMatrix eMc; // hand (end-effector) to eye (camera) transformation
// Initialize an eMc transformation used to produce the simulated input
// transformations cMo and wMe
vpTranslationVector etc(0.1, 0.2, 0.3);
erc[0] = vpMath::rad(10); // 10 deg
erc[1] = vpMath::rad(-10); // -10 deg
erc[2] = vpMath::rad(25); // 25 deg
eMc.buildFrom(etc, erc);
std::cout << "Simulated hand-eye transformation: eMc " << std::endl;
std::cout << eMc << std::endl;
std::cout << "Theta U rotation: " << vpMath::deg(erc[0]) << " " << vpMath::deg(erc[1]) << " " << vpMath::deg(erc[2])
<< std::endl;
vpColVector v_c(6); // camera velocity used to produce 6 simulated poses
for (unsigned int i = 0; i < N; i++) {
v_c = 0;
if (i == 0) {
// Initialize first poses
cMo[0].buildFrom(0, 0, 0.5, 0, 0, 0); // z=0.5 m
wMe[0].buildFrom(0, 0, 0, 0, 0, 0); // Id
} else if (i == 1)
v_c[3] = M_PI/8 ;
else if (i == 2)
v_c[4] = M_PI/8 ;
else if (i == 3)
v_c[5] = M_PI/10 ;
else if (i == 4)
v_c[0] = 0.5;
else if (i == 5)
v_c[1] = 0.8;
vpHomogeneousMatrix cMc; // camera displacement
cMc = vpExponentialMap::direct(v_c); // Compute the camera displacement
// due to the velocity applied to
// the camera
if (i > 0) {
// From the camera displacement cMc, compute the wMe and cMo matrices
cMo[i] = cMc.inverse() * cMo[i - 1];
wMe[i] = wMe[i - 1] * eMc * cMc * eMc.inverse();
}
}
// if (1) {
if (1) {
for (unsigned int i = 0; i < N; i++) {
wMo = wMe[i] * eMc * cMo[i];
std::cout << std::endl << "wMo[" << i << "] " << std::endl;
std::cout << wMo << std::endl;
std::cout << "cMo[" << i << "] " << std::endl;
std::cout << cMo[i] << std::endl;
std::cout << "wMe[" << i << "] " << std::endl;
std::cout << wMe[i] << std::endl;
}
}
// Reset the eMc matrix to eye
eMc.eye();
// Compute the eMc hand to eye transformation from six poses
// - cMo[6]: camera to object poses as six homogeneous transformations
// - wMe[6]: world to hand (end-effector) poses as six homogeneous
// transformations
int ret = vpHandEyeCalibration::calibrate(cMo, wMe, eMc);
if (ret == 0) {
std::cout << std::endl << "** Hand-eye calibration succeed" << std::endl;
std::cout << std::endl << "** Hand-eye (eMc) transformation estimated:" << std::endl;
std::cout << eMc << std::endl;
std::cout << "** Corresponding pose vector: " << vpPoseVector(eMc).t() << std::endl;
eMc.extract(erc);
std::cout << std::endl << "** Translation [m]: " << eMc[0][3] << " " << eMc[1][3] << " " << eMc[2][3] << std::endl;
std::cout << "** Rotation (theta-u representation) [rad]: " << erc.t() << std::endl;
std::cout << "** Rotation (theta-u representation) [deg]: " << vpMath::deg(erc[0]) << " " << vpMath::deg(erc[1]) << " " << vpMath::deg(erc[2]) << std::endl;
std::cout << "** Rotation (quaternion representation) [rad]: " << quaternion.t() << std::endl;
}
else {
std::cout << std::endl << "** Hand-eye calibration failed" << std::endl;
std::cout << std::endl << "Check your input data and ensure they are covering the half sphere over the chessboard." << std::endl;
std::cout << std::endl << "See https://visp-doc.inria.fr/doxygen/visp-daily/tutorial-calibration-extrinsic.html" << std::endl;
}
return EXIT_SUCCESS;
} catch (const vpException &e) {
std::cout << "Catch an exception: " << e << std::endl;
return EXIT_FAILURE;
}
#else
std::cout << "Cannot run this example: install Lapack, Eigen3 or OpenCV" << std::endl;
return EXIT_SUCCESS;
#endif
}