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cartographer/cartographer/mapping_2d/sparse_pose_graph.cc

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/*
* Copyright 2016 The Cartographer Authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "cartographer/mapping_2d/sparse_pose_graph.h"
#include <algorithm>
#include <cmath>
#include <cstdio>
#include <functional>
#include <iomanip>
#include <iostream>
#include <limits>
#include <memory>
#include <sstream>
#include <string>
#include "Eigen/Eigenvalues"
#include "cartographer/common/make_unique.h"
#include "cartographer/common/math.h"
#include "cartographer/mapping/sparse_pose_graph/proto/constraint_builder_options.pb.h"
#include "cartographer/sensor/compressed_point_cloud.h"
#include "cartographer/sensor/voxel_filter.h"
#include "glog/logging.h"
namespace cartographer {
namespace mapping_2d {
SparsePoseGraph::SparsePoseGraph(
const mapping::proto::SparsePoseGraphOptions& options,
common::ThreadPool* thread_pool,
std::deque<mapping::TrajectoryNode::ConstantData>* constant_node_data)
: options_(options),
optimization_problem_(options_.optimization_problem_options()),
constraint_builder_(options_.constraint_builder_options(), thread_pool),
constant_node_data_(constant_node_data) {}
SparsePoseGraph::~SparsePoseGraph() {
WaitForAllComputations();
common::MutexLocker locker(&mutex_);
CHECK(scan_queue_ == nullptr);
}
void SparsePoseGraph::GrowSubmapTransformsAsNeeded(
const std::vector<const mapping::Submap*>& submaps) {
CHECK(!submaps.empty());
CHECK_LT(submap_transforms_.size(), std::numeric_limits<int>::max());
const int next_transform_index = submap_transforms_.size();
// Verify that we have an index for the first submap.
const int first_transform_index = GetSubmapIndex(submaps[0]);
if (submaps.size() == 1) {
// If we don't already have an entry for this submap, add one.
if (first_transform_index == next_transform_index) {
submap_transforms_.push_back(transform::Rigid2d::Identity());
}
return;
}
CHECK_EQ(2, submaps.size());
// CHECK that we have a index for the second submap.
const int second_transform_index = GetSubmapIndex(submaps[1]);
CHECK_LE(second_transform_index, next_transform_index);
// Extrapolate if necessary.
if (second_transform_index == next_transform_index) {
const auto& first_submap_transform =
submap_transforms_[first_transform_index];
submap_transforms_.push_back(
first_submap_transform *
sparse_pose_graph::ComputeSubmapPose(*submaps[0]).inverse() *
sparse_pose_graph::ComputeSubmapPose(*submaps[1]));
}
}
void SparsePoseGraph::AddScan(
common::Time time, const transform::Rigid3d& tracking_to_pose,
const sensor::RangeData& range_data_in_pose, const transform::Rigid2d& pose,
const kalman_filter::Pose2DCovariance& covariance,
const mapping::Submaps* submaps,
const mapping::Submap* const matching_submap,
const std::vector<const mapping::Submap*>& insertion_submaps) {
const transform::Rigid3d optimized_pose(GetLocalToGlobalTransform(*submaps) *
transform::Embed3D(pose));
common::MutexLocker locker(&mutex_);
const int j = trajectory_nodes_.size();
CHECK_LT(j, std::numeric_limits<int>::max());
constant_node_data_->push_back(mapping::TrajectoryNode::ConstantData{
time, range_data_in_pose,
Compress(sensor::RangeData{Eigen::Vector3f::Zero(), {}, {}}), submaps,
tracking_to_pose});
trajectory_nodes_.push_back(mapping::TrajectoryNode{
&constant_node_data_->back(), optimized_pose,
});
trajectory_connectivity_.Add(submaps);
if (submap_indices_.count(insertion_submaps.back()) == 0) {
submap_indices_.emplace(insertion_submaps.back(),
static_cast<int>(submap_indices_.size()));
submap_states_.emplace_back();
submap_states_.back().submap = insertion_submaps.back();
submap_states_.back().trajectory = submaps;
CHECK_EQ(submap_states_.size(), submap_indices_.size());
}
const mapping::Submap* const finished_submap =
insertion_submaps.front()->finished_probability_grid != nullptr
? insertion_submaps.front()
: nullptr;
// Make sure we have a sampler for this trajectory.
if (!global_localization_samplers_[submaps]) {
global_localization_samplers_[submaps] =
common::make_unique<common::FixedRatioSampler>(
options_.global_sampling_ratio());
}
AddWorkItem([=]() REQUIRES(mutex_) {
ComputeConstraintsForScan(j, matching_submap, insertion_submaps,
finished_submap, pose, covariance);
});
}
void SparsePoseGraph::AddWorkItem(std::function<void()> work_item) {
if (scan_queue_ == nullptr) {
work_item();
} else {
scan_queue_->push_back(work_item);
}
}
void SparsePoseGraph::AddImuData(const mapping::Submaps* trajectory,
common::Time time,
const Eigen::Vector3d& linear_acceleration,
const Eigen::Vector3d& angular_velocity) {
common::MutexLocker locker(&mutex_);
AddWorkItem([=]() REQUIRES(mutex_) {
optimization_problem_.AddImuData(trajectory, time, linear_acceleration,
angular_velocity);
});
}
void SparsePoseGraph::ComputeConstraint(const int scan_index,
const int submap_index) {
const transform::Rigid2d relative_pose =
submap_transforms_[submap_index].inverse() *
optimization_problem_.node_data().at(scan_index).point_cloud_pose;
const mapping::Submaps* const scan_trajectory =
trajectory_nodes_[scan_index].constant_data->trajectory;
const mapping::Submaps* const submap_trajectory =
submap_states_[submap_index].trajectory;
// Only globally match against submaps not in this trajectory.
if (scan_trajectory != submap_trajectory &&
global_localization_samplers_[scan_trajectory]->Pulse()) {
constraint_builder_.MaybeAddGlobalConstraint(
submap_index, submap_states_[submap_index].submap, scan_index,
scan_trajectory, submap_trajectory, &trajectory_connectivity_,
&trajectory_nodes_[scan_index].constant_data->range_data_2d.returns);
} else {
const bool scan_and_submap_trajectories_connected =
reverse_connected_components_.count(scan_trajectory) > 0 &&
reverse_connected_components_.count(submap_trajectory) > 0 &&
reverse_connected_components_.at(scan_trajectory) ==
reverse_connected_components_.at(submap_trajectory);
if (scan_trajectory == submap_trajectory ||
scan_and_submap_trajectories_connected) {
constraint_builder_.MaybeAddConstraint(
submap_index, submap_states_[submap_index].submap, scan_index,
&trajectory_nodes_[scan_index].constant_data->range_data_2d.returns,
relative_pose);
}
}
}
void SparsePoseGraph::ComputeConstraintsForOldScans(
const mapping::Submap* submap) {
const int submap_index = GetSubmapIndex(submap);
const auto& node_data = optimization_problem_.node_data();
CHECK_GT(node_data.size(), 0);
CHECK_LT(node_data.size(), std::numeric_limits<int>::max());
const int num_nodes = node_data.size();
for (int scan_index = 0; scan_index < num_nodes; ++scan_index) {
if (submap_states_[submap_index].scan_indices.count(scan_index) == 0) {
ComputeConstraint(scan_index, submap_index);
}
}
}
void SparsePoseGraph::ComputeConstraintsForScan(
const int scan_index, const mapping::Submap* matching_submap,
std::vector<const mapping::Submap*> insertion_submaps,
const mapping::Submap* finished_submap, const transform::Rigid2d& pose,
const kalman_filter::Pose2DCovariance& covariance) {
GrowSubmapTransformsAsNeeded(insertion_submaps);
const int matching_index = GetSubmapIndex(matching_submap);
const transform::Rigid2d optimized_pose =
submap_transforms_[matching_index] *
sparse_pose_graph::ComputeSubmapPose(*matching_submap).inverse() * pose;
CHECK_EQ(scan_index, optimization_problem_.node_data().size());
const mapping::TrajectoryNode::ConstantData* const scan_data =
trajectory_nodes_[scan_index].constant_data;
optimization_problem_.AddTrajectoryNode(
scan_data->trajectory, scan_data->time, pose, optimized_pose);
for (const mapping::Submap* submap : insertion_submaps) {
const int submap_index = GetSubmapIndex(submap);
CHECK(!submap_states_[submap_index].finished);
submap_states_[submap_index].scan_indices.emplace(scan_index);
// Unchanged covariance as (submap <- map) is a translation.
const transform::Rigid2d constraint_transform =
sparse_pose_graph::ComputeSubmapPose(*submap).inverse() * pose;
constexpr double kFakePositionCovariance = 1e-6;
constexpr double kFakeOrientationCovariance = 1e-6;
constraints_.push_back(Constraint{
submap_index,
scan_index,
{transform::Embed3D(constraint_transform),
common::ComputeSpdMatrixSqrtInverse(
kalman_filter::Embed3D(covariance, kFakePositionCovariance,
kFakeOrientationCovariance),
options_.constraint_builder_options()
.lower_covariance_eigenvalue_bound())},
Constraint::INTRA_SUBMAP});
}
CHECK_LT(submap_states_.size(), std::numeric_limits<int>::max());
const int num_submaps = submap_states_.size();
for (int submap_index = 0; submap_index != num_submaps; ++submap_index) {
if (submap_states_[submap_index].finished) {
CHECK_EQ(submap_states_[submap_index].scan_indices.count(scan_index), 0);
ComputeConstraint(scan_index, submap_index);
}
}
if (finished_submap != nullptr) {
const int finished_submap_index = GetSubmapIndex(finished_submap);
SubmapState& finished_submap_state = submap_states_[finished_submap_index];
CHECK(!finished_submap_state.finished);
// We have a new completed submap, so we look into adding constraints for
// old scans.
ComputeConstraintsForOldScans(finished_submap);
finished_submap_state.finished = true;
}
constraint_builder_.NotifyEndOfScan(scan_index);
++num_scans_since_last_loop_closure_;
if (options_.optimize_every_n_scans() > 0 &&
num_scans_since_last_loop_closure_ > options_.optimize_every_n_scans()) {
CHECK(!run_loop_closure_);
run_loop_closure_ = true;
// If there is a 'scan_queue_' already, some other thread will take care.
if (scan_queue_ == nullptr) {
scan_queue_ = common::make_unique<std::deque<std::function<void()>>>();
HandleScanQueue();
}
}
}
void SparsePoseGraph::HandleScanQueue() {
constraint_builder_.WhenDone(
[this](const sparse_pose_graph::ConstraintBuilder::Result& result) {
constraints_.insert(constraints_.end(), result.begin(), result.end());
RunOptimization();
common::MutexLocker locker(&mutex_);
num_scans_since_last_loop_closure_ = 0;
run_loop_closure_ = false;
while (!run_loop_closure_) {
if (scan_queue_->empty()) {
LOG(INFO) << "We caught up. Hooray!";
scan_queue_.reset();
return;
}
scan_queue_->front()();
scan_queue_->pop_front();
}
// We have to optimize again.
HandleScanQueue();
});
}
void SparsePoseGraph::WaitForAllComputations() {
bool notification = false;
common::MutexLocker locker(&mutex_);
const int num_finished_scans_at_start =
constraint_builder_.GetNumFinishedScans();
while (!locker.AwaitWithTimeout(
[this]() REQUIRES(mutex_) {
return static_cast<size_t>(constraint_builder_.GetNumFinishedScans()) ==
trajectory_nodes_.size();
},
common::FromSeconds(1.))) {
std::ostringstream progress_info;
progress_info << "Optimizing: " << std::fixed << std::setprecision(1)
<< 100. *
(constraint_builder_.GetNumFinishedScans() -
num_finished_scans_at_start) /
(trajectory_nodes_.size() -
num_finished_scans_at_start)
<< "%...";
std::cout << "\r\x1b[K" << progress_info.str() << std::flush;
}
std::cout << "\r\x1b[KOptimizing: Done. " << std::endl;
constraint_builder_.WhenDone(
[this, &notification](
const sparse_pose_graph::ConstraintBuilder::Result& result) {
constraints_.insert(constraints_.end(), result.begin(), result.end());
common::MutexLocker locker(&mutex_);
notification = true;
});
locker.Await([&notification]() { return notification; });
}
void SparsePoseGraph::RunFinalOptimization() {
WaitForAllComputations();
optimization_problem_.SetMaxNumIterations(
options_.max_num_final_iterations());
RunOptimization();
optimization_problem_.SetMaxNumIterations(
options_.optimization_problem_options()
.ceres_solver_options()
.max_num_iterations());
}
void SparsePoseGraph::RunOptimization() {
if (!submap_transforms_.empty()) {
optimization_problem_.Solve(constraints_, &submap_transforms_);
common::MutexLocker locker(&mutex_);
const auto& node_data = optimization_problem_.node_data();
const size_t num_optimized_poses = node_data.size();
for (size_t i = 0; i != num_optimized_poses; ++i) {
trajectory_nodes_[i].pose =
transform::Rigid3d(transform::Embed3D(node_data[i].point_cloud_pose));
}
// Extrapolate all point cloud poses that were added later.
std::unordered_map<const mapping::Submaps*, transform::Rigid3d>
extrapolation_transforms;
for (size_t i = num_optimized_poses; i != trajectory_nodes_.size(); ++i) {
const mapping::Submaps* trajectory =
trajectory_nodes_[i].constant_data->trajectory;
if (extrapolation_transforms.count(trajectory) == 0) {
extrapolation_transforms[trajectory] = transform::Rigid3d(
ExtrapolateSubmapTransforms(submap_transforms_, *trajectory)
.back() *
ExtrapolateSubmapTransforms(optimized_submap_transforms_,
*trajectory)
.back()
.inverse());
}
trajectory_nodes_[i].pose =
extrapolation_transforms[trajectory] * trajectory_nodes_[i].pose;
}
optimized_submap_transforms_ = submap_transforms_;
connected_components_ = trajectory_connectivity_.ConnectedComponents();
reverse_connected_components_.clear();
for (size_t i = 0; i != connected_components_.size(); ++i) {
for (const auto* trajectory : connected_components_[i]) {
reverse_connected_components_.emplace(trajectory, i);
}
}
}
}
std::vector<mapping::TrajectoryNode> SparsePoseGraph::GetTrajectoryNodes() {
common::MutexLocker locker(&mutex_);
return trajectory_nodes_;
}
std::vector<SparsePoseGraph::SubmapState> SparsePoseGraph::GetSubmapStates() {
common::MutexLocker locker(&mutex_);
return submap_states_;
}
std::vector<SparsePoseGraph::Constraint> SparsePoseGraph::constraints() {
return constraints_;
}
transform::Rigid3d SparsePoseGraph::GetLocalToGlobalTransform(
const mapping::Submaps& submaps) {
return GetSubmapTransforms(submaps).back() *
submaps.Get(submaps.size() - 1)->local_pose().inverse();
}
std::vector<std::vector<const mapping::Submaps*>>
SparsePoseGraph::GetConnectedTrajectories() {
common::MutexLocker locker(&mutex_);
return connected_components_;
}
std::vector<transform::Rigid3d> SparsePoseGraph::GetSubmapTransforms(
const mapping::Submaps& submaps) {
common::MutexLocker locker(&mutex_);
return ExtrapolateSubmapTransforms(optimized_submap_transforms_, submaps);
}
std::vector<transform::Rigid3d> SparsePoseGraph::ExtrapolateSubmapTransforms(
const std::vector<transform::Rigid2d>& submap_transforms,
const mapping::Submaps& submaps) const {
std::vector<transform::Rigid3d> result;
int i = 0;
// Submaps for which we have optimized poses.
for (; i < submaps.size(); ++i) {
const mapping::Submap* submap = submaps.Get(i);
const auto submap_and_index = submap_indices_.find(submap);
// Determine if we have a loop-closed transform for this submap.
if (submap_and_index == submap_indices_.end() ||
static_cast<size_t>(submap_and_index->second) >=
submap_transforms.size()) {
break;
}
result.push_back(
transform::Embed3D(submap_transforms[submap_and_index->second]));
}
// Extrapolate to the remaining submaps.
for (; i < submaps.size(); ++i) {
if (i == 0) {
result.push_back(transform::Rigid3d::Identity());
continue;
}
result.push_back(result.back() *
submaps.Get(result.size() - 1)->local_pose().inverse() *
submaps.Get(result.size())->local_pose());
}
return result;
}
} // namespace mapping_2d
} // namespace cartographer
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