exponentialMap.cpp

/****************************************************************************
 *
 * ViSP, open source Visual Servoing Platform software.
 * Copyright (C) 2005 - 2019 by Inria. All rights reserved.
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 * Inria Rennes - Bretagne Atlantique
 * Campus Universitaire de Beaulieu
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 *
 * Description:
 * Test some vpColVector functionalities.
 *
 * Authors:
 * Eric Marchand
 *
 *****************************************************************************/

#include <visp3/core/vpColVector.h>
#include <visp3/core/vpExponentialMap.h>
#include <visp3/core/vpHomogeneousMatrix.h>
#include <visp3/core/vpRotationVector.h>
#include <visp3/core/vpRxyzVector.h>
#include <visp3/core/vpThetaUVector.h>
#include <visp3/core/vpTranslationVector.h>

int main()
{
  try {
    vpTranslationVector t;
    t[0] = 0.1;  // t_x in m/s
    t[1] = 0.2f; // t_y in m/s
    t[2] = 0.f;  // t_z in m/s

    vpRxyzVector rxyz;
    rxyz[0] = vpMath::rad(0.f);  // r_x in rad/s
    rxyz[1] = vpMath::rad(0.f);  // r_y in rad/s
    rxyz[2] = vpMath::rad(90.f); // r_z in rad/s

    // Build a ThetaU rotation vector from a Rxyz vector
    vpThetaUVector tu;
    tu.buildFrom(rxyz);

    vpColVector v(6); // Velocity vector [t, thetaU]^t

    v[0] = t[0];  // t_x
    v[1] = t[1];  // t_y
    v[2] = t[2];  // t_z
    v[3] = tu[0]; // ThetaU_x
    v[4] = tu[1]; // ThetaU_y
    v[5] = tu[2]; // ThetaU_z

    std::cout << "Considered velocity : \n" << v << std::endl;

    vpHomogeneousMatrix M;

    // Compute the displacement from the velocity applied during 1 second
    M = vpExponentialMap::direct(v);

    {
      // Extract translation from homogenous matrix
      vpTranslationVector dt; // translation displacement
      M.extract(dt);

      // Extract rotation from homogenous matrix
      vpRotationMatrix R;
      M.extract(R);
      vpRxyzVector drxyz(R); // rotational displacement

      std::cout << "Displacement if velocity is applied during 1 s : \n" << dt << " " << drxyz << std::endl;
    }

    // Compute the displacement from the velocity applied during 2 seconds
    M = vpExponentialMap::direct(v, 2.f);

    {
      // Extract translation from homogenous matrix
      vpTranslationVector dt; // translation displacement
      M.extract(dt);

      // Extract rotation from homogenous matrix
      vpRotationMatrix R;
      M.extract(R);
      vpRxyzVector drxyz(R); // rotational displacement

      std::cout << "Displacement if velocity is applied during 2 s : \n" << dt << " " << drxyz << std::endl;
    }

    // Compute the velocity from the displacement observed during 2 seconds
    v = vpExponentialMap::inverse(M, 2.f);

    std::cout << "Velocity from displacement observed during 2 s: \n" << v << std::endl;
    return EXIT_SUCCESS;
  } catch (const vpException &e) {
    std::cout << "Catch an exception: " << e << std::endl;
    return EXIT_FAILURE;
  }
}