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#ifndef PCL_REGISTRATION_IMPL_IA_KFPCS_H_
#define PCL_REGISTRATION_IMPL_IA_KFPCS_H_
#include <limits>
namespace pcl {
namespace registration {
template <typename PointSource, typename PointTarget, typename NormalT, typename Scalar>
KFPCSInitialAlignment<PointSource, PointTarget, NormalT, Scalar>::
KFPCSInitialAlignment()
: indices_validation_(new pcl::Indices)
{
reg_name_ = "pcl::registration::KFPCSInitialAlignment";
}
template <typename PointSource, typename PointTarget, typename NormalT, typename Scalar>
bool
KFPCSInitialAlignment<PointSource, PointTarget, NormalT, Scalar>::initCompute()
{
// due to sparse keypoint cloud, do not normalize delta with estimated point density
if (normalize_delta_) {
PCL_WARN("[%s::initCompute] Delta should be set according to keypoint precision! "
"Normalization according to point cloud density is ignored.\n",
reg_name_.c_str());
normalize_delta_ = false;
}
// initialize as in fpcs
pcl::registration::FPCSInitialAlignment<PointSource, PointTarget, NormalT, Scalar>::
initCompute();
// set the threshold values with respect to keypoint characteristics
max_pair_diff_ = delta_ * 1.414f; // diff between 2 points of delta_ accuracy
coincidation_limit_ = delta_ * 2.828f; // diff between diff of 2 points
max_edge_diff_ =
delta_ *
3.f; // diff between 2 points + some inaccuracy due to quadruple orientation
max_mse_ =
powf(delta_ * 4.f, 2.f); // diff between 2 points + some registration inaccuracy
max_inlier_dist_sqr_ =
powf(delta_ * 8.f,
2.f); // set rel. high, because MSAC is used (residual based score function)
// check use of translation costs and calculate upper boundary if not set by user
if (upper_trl_boundary_ < 0)
upper_trl_boundary_ = diameter_ * (1.f - approx_overlap_) * 0.5f;
if (!(lower_trl_boundary_ < 0) && upper_trl_boundary_ > lower_trl_boundary_)
use_trl_score_ = true;
else
lambda_ = 0.f;
// generate a subset of indices of size ransac_iterations_ on which to evaluate
// candidates on
std::size_t nr_indices = indices_->size();
if (nr_indices < static_cast<std::size_t>(ransac_iterations_))
indices_validation_ = indices_;
else
for (int i = 0; i < ransac_iterations_; i++)
indices_validation_->push_back((*indices_)[rand() % nr_indices]);
return (true);
}
template <typename PointSource, typename PointTarget, typename NormalT, typename Scalar>
void
KFPCSInitialAlignment<PointSource, PointTarget, NormalT, Scalar>::handleMatches(
const pcl::Indices& base_indices,
std::vector<pcl::Indices>& matches,
MatchingCandidates& candidates)
{
candidates.clear();
// loop over all Candidate matches
for (auto& match : matches) {
Eigen::Matrix4f transformation_temp;
pcl::Correspondences correspondences_temp;
float fitness_score =
std::numeric_limits<float>::max(); // reset to std::numeric_limits<float>::max()
// to accept all candidates and not only best
// determine corresondences between base and match according to their distance to
// centroid
linkMatchWithBase(base_indices, match, correspondences_temp);
// check match based on residuals of the corresponding points after transformation
if (validateMatch(base_indices, match, correspondences_temp, transformation_temp) <
0)
continue;
// check resulting transformation using a sub sample of the source point cloud
// all candidates are stored and later sorted according to their fitness score
validateTransformation(transformation_temp, fitness_score);
// store all valid match as well as associated score and transformation
candidates.push_back(
MatchingCandidate(fitness_score, correspondences_temp, transformation_temp));
}
}
template <typename PointSource, typename PointTarget, typename NormalT, typename Scalar>
int
KFPCSInitialAlignment<PointSource, PointTarget, NormalT, Scalar>::
validateTransformation(Eigen::Matrix4f& transformation, float& fitness_score)
{
// transform sub sampled source cloud
PointCloudSource source_transformed;
pcl::transformPointCloud(
*input_, *indices_validation_, source_transformed, transformation);
const std::size_t nr_points = source_transformed.size();
float score_a = 0.f, score_b = 0.f;
// residual costs based on mse
pcl::Indices ids;
std::vector<float> dists_sqr;
for (const auto& source : source_transformed) {
// search for nearest point using kd tree search
tree_->nearestKSearch(source, 1, ids, dists_sqr);
score_a += (dists_sqr[0] < max_inlier_dist_sqr_ ? dists_sqr[0]
: max_inlier_dist_sqr_); // MSAC
}
score_a /= (max_inlier_dist_sqr_ * nr_points); // MSAC
// score_a = 1.f - (1.f - score_a) / (1.f - approx_overlap_); // make score relative
// to estimated overlap
// translation score (solutions with small translation are down-voted)
float scale = 1.f;
if (use_trl_score_) {
float trl = transformation.rightCols<1>().head(3).norm();
float trl_ratio =
(trl - lower_trl_boundary_) / (upper_trl_boundary_ - lower_trl_boundary_);
score_b =
(trl_ratio < 0.f ? 1.f
: (trl_ratio > 1.f ? 0.f
: 0.5f * sin(M_PI * trl_ratio + M_PI_2) +
0.5f)); // sinusoidal costs
scale += lambda_;
}
// calculate the fitness and return unsuccessful if smaller than previous ones
float fitness_score_temp = (score_a + lambda_ * score_b) / scale;
if (fitness_score_temp > fitness_score)
return (-1);
fitness_score = fitness_score_temp;
return (0);
}
template <typename PointSource, typename PointTarget, typename NormalT, typename Scalar>
void
KFPCSInitialAlignment<PointSource, PointTarget, NormalT, Scalar>::finalCompute(
const std::vector<MatchingCandidates>& candidates)
{
// reorganize candidates into single vector
std::size_t total_size = 0;
for (const auto& candidate : candidates)
total_size += candidate.size();
candidates_.clear();
candidates_.reserve(total_size);
for (const auto& candidate : candidates)
for (const auto& match : candidate)
candidates_.push_back(match);
// sort according to score value
std::sort(candidates_.begin(), candidates_.end(), by_score());
// return here if no score was valid, i.e. all scores are
// std::numeric_limits<float>::max()
if (candidates_[0].fitness_score == std::numeric_limits<float>::max()) {
converged_ = false;
return;
}
// save best candidate as output result
// note, all other candidates are accessible via getNBestCandidates () and
// getTBestCandidates ()
fitness_score_ = candidates_[0].fitness_score;
final_transformation_ = candidates_[0].transformation;
*correspondences_ = candidates_[0].correspondences;
// here we define convergence if resulting score is above threshold
converged_ = fitness_score_ < score_threshold_;
}
template <typename PointSource, typename PointTarget, typename NormalT, typename Scalar>
void
KFPCSInitialAlignment<PointSource, PointTarget, NormalT, Scalar>::getNBestCandidates(
int n, float min_angle3d, float min_translation3d, MatchingCandidates& candidates)
{
candidates.clear();
// loop over all candidates starting from the best one
for (const auto& candidate : candidates_) {
// stop if current candidate has no valid score
if (candidate.fitness_score == std::numeric_limits<float>::max())
return;
// check if current candidate is a unique one compared to previous using the
// min_diff threshold
bool unique = true;
for (const auto& c2 : candidates) {
Eigen::Matrix4f diff =
candidate.transformation.colPivHouseholderQr().solve(c2.transformation);
const float angle3d = Eigen::AngleAxisf(diff.block<3, 3>(0, 0)).angle();
const float translation3d = diff.block<3, 1>(0, 3).norm();
unique = angle3d > min_angle3d && translation3d > min_translation3d;
if (!unique) {
break;
}
}
// add candidate to best candidates
if (unique)
candidates.push_back(candidate);
// stop if n candidates are reached
if (candidates.size() == n)
return;
}
}
template <typename PointSource, typename PointTarget, typename NormalT, typename Scalar>
void
KFPCSInitialAlignment<PointSource, PointTarget, NormalT, Scalar>::getTBestCandidates(
float t, float min_angle3d, float min_translation3d, MatchingCandidates& candidates)
{
candidates.clear();
// loop over all candidates starting from the best one
for (const auto& candidate : candidates_) {
// stop if current candidate has score below threshold
if (candidate.fitness_score > t)
return;
// check if current candidate is a unique one compared to previous using the
// min_diff threshold
bool unique = true;
for (const auto& c2 : candidates) {
Eigen::Matrix4f diff =
candidate.transformation.colPivHouseholderQr().solve(c2.transformation);
const float angle3d = Eigen::AngleAxisf(diff.block<3, 3>(0, 0)).angle();
const float translation3d = diff.block<3, 1>(0, 3).norm();
unique = angle3d > min_angle3d && translation3d > min_translation3d;
if (!unique) {
break;
}
}
// add candidate to best candidates
if (unique)
candidates.push_back(candidate);
}
}
} // namespace registration
} // namespace pcl
#endif // PCL_REGISTRATION_IMPL_IA_KFPCS_H_