sac_model_registration.hpp

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#ifndef PCL_SAMPLE_CONSENSUS_IMPL_SAC_MODEL_REGISTRATION_H_
#define PCL_SAMPLE_CONSENSUS_IMPL_SAC_MODEL_REGISTRATION_H_

#include <pcl/sample_consensus/sac_model_registration.h>
#include <pcl/common/point_operators.h>
#include <pcl/common/eigen.h>
#include <pcl/point_types.h>

template <typename PointT> bool
pcl::SampleConsensusModelRegistration<PointT>::isSampleGood (const std::vector<int> &samples) const
{
  using namespace pcl::common;
  using namespace pcl::traits;

  PointT p10 = input_->points[samples[1]] - input_->points[samples[0]];
  PointT p20 = input_->points[samples[2]] - input_->points[samples[0]];
  PointT p21 = input_->points[samples[2]] - input_->points[samples[1]];

  return ((p10.x * p10.x + p10.y * p10.y + p10.z * p10.z) > sample_dist_thresh_ && 
          (p20.x * p20.x + p20.y * p20.y + p20.z * p20.z) > sample_dist_thresh_ && 
          (p21.x * p21.x + p21.y * p21.y + p21.z * p21.z) > sample_dist_thresh_);
}

template <typename PointT> bool
pcl::SampleConsensusModelRegistration<PointT>::computeModelCoefficients (const std::vector<int> &samples, Eigen::VectorXf &model_coefficients)
{
  if (!target_)
  {
    PCL_ERROR ("[pcl::SampleConsensusModelRegistration::computeModelCoefficients] No target dataset given!\n");
    return (false);
  }
  // Need 3 samples
  if (samples.size () != 3)
    return (false);

  std::vector<int> indices_tgt (3);
  for (int i = 0; i < 3; ++i)
    indices_tgt[i] = correspondences_[samples[i]];

  estimateRigidTransformationSVD (*input_, samples, *target_, indices_tgt, model_coefficients);
  return (true);
}

template <typename PointT> void
pcl::SampleConsensusModelRegistration<PointT>::getDistancesToModel (const Eigen::VectorXf &model_coefficients, std::vector<double> &distances) 
{
  if (indices_->size () != indices_tgt_->size ())
  {
    PCL_ERROR ("[pcl::SampleConsensusModelRegistration::getDistancesToModel] Number of source indices (%zu) differs than number of target indices (%zu)!\n", indices_->size (), indices_tgt_->size ());
    distances.clear ();
    return;
  }
  if (!target_)
  {
    PCL_ERROR ("[pcl::SampleConsensusModelRegistration::getDistanceToModel] No target dataset given!\n");
    return;
  }
  // Check if the model is valid given the user constraints
  if (!isModelValid (model_coefficients))
  {
    distances.clear ();
    return;
  }
  distances.resize (indices_->size ());

  // Get the 4x4 transformation
  Eigen::Matrix4f transform;
  transform.row (0).matrix () = model_coefficients.segment<4>(0);
  transform.row (1).matrix () = model_coefficients.segment<4>(4);
  transform.row (2).matrix () = model_coefficients.segment<4>(8);
  transform.row (3).matrix () = model_coefficients.segment<4>(12);

  for (size_t i = 0; i < indices_->size (); ++i)
  {
    Eigen::Vector4f pt_src (input_->points[(*indices_)[i]].x, 
                            input_->points[(*indices_)[i]].y, 
                            input_->points[(*indices_)[i]].z, 1); 
    Eigen::Vector4f pt_tgt (target_->points[(*indices_tgt_)[i]].x, 
                            target_->points[(*indices_tgt_)[i]].y, 
                            target_->points[(*indices_tgt_)[i]].z, 1); 

    Eigen::Vector4f p_tr (transform * pt_src);
    // Calculate the distance from the transformed point to its correspondence
    // need to compute the real norm here to keep MSAC and friends general
    distances[i] = (p_tr - pt_tgt).norm ();
  }
}

template <typename PointT> void
pcl::SampleConsensusModelRegistration<PointT>::selectWithinDistance (const Eigen::VectorXf &model_coefficients, const double threshold, std::vector<int> &inliers) 
{
  if (indices_->size () != indices_tgt_->size ())
  {
    PCL_ERROR ("[pcl::SampleConsensusModelRegistration::selectWithinDistance] Number of source indices (%zu) differs than number of target indices (%zu)!\n", indices_->size (), indices_tgt_->size ());
    inliers.clear ();
    return;
  }
  if (!target_)
  {
    PCL_ERROR ("[pcl::SampleConsensusModelRegistration::selectWithinDistance] No target dataset given!\n");
    return;
  }

  double thresh = threshold * threshold;

  // Check if the model is valid given the user constraints
  if (!isModelValid (model_coefficients))
  {
    inliers.clear ();
    return;
  }
  
  int nr_p = 0;
  inliers.resize (indices_->size ());
  error_sqr_dists_.resize (indices_->size ());

  Eigen::Matrix4f transform;
  transform.row (0).matrix () = model_coefficients.segment<4>(0);
  transform.row (1).matrix () = model_coefficients.segment<4>(4);
  transform.row (2).matrix () = model_coefficients.segment<4>(8);
  transform.row (3).matrix () = model_coefficients.segment<4>(12);

  for (size_t i = 0; i < indices_->size (); ++i)
  {
    Eigen::Vector4f pt_src (input_->points[(*indices_)[i]].x, 
                            input_->points[(*indices_)[i]].y, 
                            input_->points[(*indices_)[i]].z, 1); 
    Eigen::Vector4f pt_tgt (target_->points[(*indices_tgt_)[i]].x, 
                            target_->points[(*indices_tgt_)[i]].y, 
                            target_->points[(*indices_tgt_)[i]].z, 1); 

    Eigen::Vector4f p_tr (transform * pt_src);
  
    float distance = (p_tr - pt_tgt).squaredNorm (); 
    // Calculate the distance from the transformed point to its correspondence
    if (distance < thresh)
    {
      inliers[nr_p] = (*indices_)[i];
      error_sqr_dists_[nr_p] = static_cast<double> (distance);
      ++nr_p;
    }
  }
  inliers.resize (nr_p);
  error_sqr_dists_.resize (nr_p);
} 

template <typename PointT> int
pcl::SampleConsensusModelRegistration<PointT>::countWithinDistance (
    const Eigen::VectorXf &model_coefficients, const double threshold)
{
  if (indices_->size () != indices_tgt_->size ())
  {
    PCL_ERROR ("[pcl::SampleConsensusModelRegistration::countWithinDistance] Number of source indices (%zu) differs than number of target indices (%zu)!\n", indices_->size (), indices_tgt_->size ());
    return (0);
  }
  if (!target_)
  {
    PCL_ERROR ("[pcl::SampleConsensusModelRegistration::countWithinDistance] No target dataset given!\n");
    return (0);
  }

  double thresh = threshold * threshold;

  // Check if the model is valid given the user constraints
  if (!isModelValid (model_coefficients))
    return (0);
  
  Eigen::Matrix4f transform;
  transform.row (0).matrix () = model_coefficients.segment<4>(0);
  transform.row (1).matrix () = model_coefficients.segment<4>(4);
  transform.row (2).matrix () = model_coefficients.segment<4>(8);
  transform.row (3).matrix () = model_coefficients.segment<4>(12);

  int nr_p = 0; 
  for (size_t i = 0; i < indices_->size (); ++i)
  {
    Eigen::Vector4f pt_src (input_->points[(*indices_)[i]].x, 
                            input_->points[(*indices_)[i]].y, 
                            input_->points[(*indices_)[i]].z, 1); 
    Eigen::Vector4f pt_tgt (target_->points[(*indices_tgt_)[i]].x, 
                            target_->points[(*indices_tgt_)[i]].y, 
                            target_->points[(*indices_tgt_)[i]].z, 1); 

    Eigen::Vector4f p_tr (transform * pt_src);
    // Calculate the distance from the transformed point to its correspondence
    if ((p_tr - pt_tgt).squaredNorm () < thresh)
      nr_p++;
  }
  return (nr_p);
} 

template <typename PointT> void
pcl::SampleConsensusModelRegistration<PointT>::optimizeModelCoefficients (const std::vector<int> &inliers, const Eigen::VectorXf &model_coefficients, Eigen::VectorXf &optimized_coefficients) 
{
  if (indices_->size () != indices_tgt_->size ())
  {
    PCL_ERROR ("[pcl::SampleConsensusModelRegistration::optimizeModelCoefficients] Number of source indices (%zu) differs than number of target indices (%zu)!\n", indices_->size (), indices_tgt_->size ());
    optimized_coefficients = model_coefficients;
    return;
  }

  // Check if the model is valid given the user constraints
  if (!isModelValid (model_coefficients) || !target_)
  {
    optimized_coefficients = model_coefficients;
    return;
  }

  std::vector<int> indices_src (inliers.size ());
  std::vector<int> indices_tgt (inliers.size ());
  for (size_t i = 0; i < inliers.size (); ++i)
  {
    indices_src[i] = inliers[i];
    indices_tgt[i] = correspondences_[indices_src[i]];
  }

  estimateRigidTransformationSVD (*input_, indices_src, *target_, indices_tgt, optimized_coefficients);
}

template <typename PointT> void
pcl::SampleConsensusModelRegistration<PointT>::estimateRigidTransformationSVD (
    const pcl::PointCloud<PointT> &cloud_src, 
    const std::vector<int> &indices_src, 
    const pcl::PointCloud<PointT> &cloud_tgt,
    const std::vector<int> &indices_tgt, 
    Eigen::VectorXf &transform)
{
  transform.resize (16);

  Eigen::Matrix<double, 3, Eigen::Dynamic> src (3, indices_src.size ());
  Eigen::Matrix<double, 3, Eigen::Dynamic> tgt (3, indices_tgt.size ());

  for (size_t i = 0; i < indices_src.size (); ++i)
  {
    src (0, i) = cloud_src[indices_src[i]].x;
    src (1, i) = cloud_src[indices_src[i]].y;
    src (2, i) = cloud_src[indices_src[i]].z;

    tgt (0, i) = cloud_tgt[indices_tgt[i]].x;
    tgt (1, i) = cloud_tgt[indices_tgt[i]].y;
    tgt (2, i) = cloud_tgt[indices_tgt[i]].z;
  }

  // Call Umeyama directly from Eigen
  Eigen::Matrix4d transformation_matrix = pcl::umeyama (src, tgt, false);

  // Return the correct transformation
  transform.segment<4> (0).matrix () = transformation_matrix.cast<float> ().row (0); 
  transform.segment<4> (4).matrix () = transformation_matrix.cast<float> ().row (1);
  transform.segment<4> (8).matrix () = transformation_matrix.cast<float> ().row (2);
  transform.segment<4> (12).matrix () = transformation_matrix.cast<float> ().row (3);
}

#define PCL_INSTANTIATE_SampleConsensusModelRegistration(T) template class PCL_EXPORTS pcl::SampleConsensusModelRegistration<T>;

#endif    // PCL_SAMPLE_CONSENSUS_IMPL_SAC_MODEL_REGISTRATION_H_