/home/runner/work/beluga/beluga/beluga_ros/include/beluga_ros/particle_cloud.hpp Source File

/home/runner/work/beluga/beluga/beluga_ros/include/beluga_ros/particle_cloud.hpp Source File#

Beluga ROS: /home/runner/work/beluga/beluga/beluga_ros/include/beluga_ros/particle_cloud.hpp Source File
Beluga ROS
 // Copyright 2024 Ekumen, Inc.
 //
 // 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.
  
 #ifndef BELUGA_ROS_PARTICLE_CLOUD_HPP
 #define BELUGA_ROS_PARTICLE_CLOUD_HPP
  
 #include <cmath>
 #include <map>
 #include <memory>
 #include <type_traits>
  
 #include <range/v3/range/primitives.hpp>
 #include <range/v3/view/take_exactly.hpp>
  
 #include <sophus/se2.hpp>
 #include <sophus/se3.hpp>
 #include <sophus/types.hpp>
  
 #include <beluga/algorithm/spatial_hash.hpp>
 #include <beluga/primitives.hpp>
 #include <beluga/views/sample.hpp>
 #include <beluga/views/zip.hpp>
  
 #include <beluga_ros/messages.hpp>
 #include <beluga_ros/tf2_eigen.hpp>
 #include <beluga_ros/tf2_sophus.hpp>
  
 namespace beluga_ros {
  
 namespace detail {
  
  
 inline beluga_ros::msg::ColorRGBA alphaHueToRGBA(float hue, float alpha) {
   beluga_ros::msg::ColorRGBA message;
   // https://en.wikipedia.org/wiki/HSL_and_HSV#HSV_to_RGB_alternative
   // specialized for V = S = 1 and using single precision floats because
   // that is what the color message expects.
   const auto kr = std::fmod(5.0F + hue / 60.0F, 6.0F);
   const auto kg = std::fmod(3.0F + hue / 60.0F, 6.0F);
   const auto kb = std::fmod(1.0F + hue / 60.0F, 6.0F);
   message.r = 1.0F - 1.0F * std::max(0.0F, std::min({kr, 4.0F - kr, 1.0F}));
   message.g = 1.0F - 1.0F * std::max(0.0F, std::min({kg, 4.0F - kg, 1.0F}));
   message.b = 1.0F - 1.0F * std::max(0.0F, std::min({kb, 4.0F - kb, 1.0F}));
   message.a = alpha;
   return message;
 }
  
 template <class T>
 struct almost_equal_to;
  
 template <typename Scalar>
 struct almost_equal_to<Sophus::SE2<Scalar>> {
  
   explicit almost_equal_to(Scalar _linear_resolution, Scalar _angular_resolution)
       : linear_resolution(_linear_resolution), angular_resolution(_angular_resolution) {}
  
   bool operator()(const Sophus::SE2<Scalar>& a, const Sophus::SE2<Scalar>& b) const {
     using std::abs, std::atan, std::tan;
     return (abs(a.translation().x() - b.translation().x()) < linear_resolution) &&
            (abs(a.translation().y() - b.translation().y()) < linear_resolution) &&
            (abs(atan(tan(a.so2().log() - b.so2().log()))) < angular_resolution);
   }
  
   const Scalar linear_resolution;   
   const Scalar angular_resolution;  
 };
  
 }  // namespace detail
  
  
 template <
     class Particles,
     class Particle = ranges::range_value_t<Particles>,
     class State = typename beluga::state_t<Particle>,
     class Scalar = typename State::Scalar,
     typename = std::enable_if_t<
         std::is_same_v<State, typename Sophus::SE2<Scalar>> || std::is_same_v<State, typename Sophus::SE3<Scalar>>>>
 beluga_ros::msg::PoseArray&
 assign_particle_cloud(Particles&& particles, std::size_t size, beluga_ros::msg::PoseArray& message) {
   static_assert(ranges::sized_range<decltype(particles)>);
   message.poses.clear();
   if (ranges::size(particles) > 0) {
     message.poses.reserve(size);
     for (const auto& particle : particles | beluga::views::sample | ranges::views::take_exactly(size)) {
       auto& pose = message.poses.emplace_back();
       tf2::toMsg(beluga::state(particle), pose);
     }
   }
   return message;
 }
  
  
 template <class Particles, class Message>
 Message& assign_particle_cloud(Particles&& particles, Message& message) {
   static_assert(ranges::sized_range<decltype(particles)>);
   return assign_particle_cloud(std::forward<Particles>(particles), ranges::size(particles), message);
 }
  
  
 template <
     class Particles,
     class Particle = ranges::range_value_t<Particles>,
     class State = typename beluga::state_t<Particle>,
     class Weight = typename beluga::weight_t<Particle>,
     class Scalar = typename State::Scalar,
     typename = std::enable_if_t<std::is_same_v<State, typename Sophus::SE2<Scalar>>>>
 beluga_ros::msg::MarkerArray& assign_particle_cloud(
     Particles&& particles,
     Scalar linear_resolution,
     Scalar angular_resolution,
     beluga_ros::msg::MarkerArray& message) {
   // Particle weights from the filter may or may not be representative of the
   // true distribution. If we resampled, they are not, and there will be multiple copies
   // of the most likely candidates, all with unit weight. In this case the number of copies
   // is a proxy for the prob density at each candidate. If we did not resample before updating
   // the estimation and publishing this message (which can happen if the resample interval
   // is set to something other than 1), then all particles are expected to be different
   // and their weights are proportional to the prob density at each candidate.
   //
   // Only the combination of both the state distribution and the candidate weights together
   // provide information about the probability density at each candidate.
   auto max_bin_weight = Weight{1e-3};
   auto states = beluga::views::states(particles);
   auto weights = beluga::views::weights(particles);
   using StateHistogram = std::unordered_map<State, Weight, beluga::spatial_hash<State>, detail::almost_equal_to<State>>;
   auto histogram = StateHistogram{
       10U, beluga::spatial_hash<State>{linear_resolution, angular_resolution},
       detail::almost_equal_to<State>{linear_resolution, angular_resolution}};
   for (const auto& [state, weight] : beluga::views::zip(states, weights)) {
     auto& bin_weight = histogram[state];
     bin_weight += weight;
     if (bin_weight > max_bin_weight) {
       max_bin_weight = bin_weight;
     }
   }
  
   message.markers.clear();
  
   if (histogram.empty()) {
     return message;
   }
  
   // There are no arrow list markers yet (https://github.com/ros2/rviz/pull/972)
   // so we replicate them using a line list for arrow bodies and a triangle list
   // for arrow heads.
   constexpr auto kArrowBodyLength = Scalar{0.5};
   constexpr auto kArrowHeadLength = Scalar{0.1};
   constexpr auto kArrowHeadWidth = kArrowHeadLength / Scalar{5.0};
   constexpr auto kArrowLength = kArrowBodyLength + kArrowHeadLength;
  
   using Translation = typename State::TranslationType;
   const auto arrow_body_base = Translation::Zero();
   const auto arrow_head_tip = kArrowLength * Translation::UnitX();
   const auto arrow_head_base = kArrowBodyLength * Translation::UnitX();
   const auto arrow_head_right_corner =
       kArrowBodyLength * Translation::UnitX() - (kArrowHeadWidth / Scalar{2.0}) * Translation::UnitY();
   const auto arrow_head_left_corner =
       kArrowBodyLength * Translation::UnitX() + (kArrowHeadWidth / Scalar{2.0}) * Translation::UnitY();
  
   message.markers.reserve(2);
   auto& arrow_bodies = message.markers.emplace_back();
   arrow_bodies.id = 0;
   arrow_bodies.ns = "bodies";
   arrow_bodies.color.a = 1.0;
   arrow_bodies.pose.orientation.w = 1.0;
   arrow_bodies.lifetime.sec = 1;
   arrow_bodies.type = beluga_ros::msg::Marker::LINE_LIST;
   arrow_bodies.action = beluga_ros::msg::Marker::ADD;
   arrow_bodies.points.reserve(histogram.size() * 2);  // 2 vertices per arrow body
   arrow_bodies.colors.reserve(histogram.size() * 2);
  
   auto& arrow_heads = message.markers.emplace_back();
   arrow_heads.id = 1;
   arrow_heads.ns = "heads";
   arrow_heads.scale.x = 1.0;
   arrow_heads.scale.y = 1.0;
   arrow_heads.scale.z = 1.0;
   arrow_heads.color.a = 1.0;
   arrow_heads.pose.orientation.w = 1.0;
   arrow_heads.lifetime.sec = 1;
   arrow_heads.type = beluga_ros::msg::Marker::TRIANGLE_LIST;
   arrow_heads.action = beluga_ros::msg::Marker::ADD;
   arrow_heads.points.reserve(histogram.size() * 3);  // 3 vertices per arrow head
   arrow_heads.colors.reserve(histogram.size() * 3);
  
   auto min_scale_factor = Weight{1.0};
   for (const auto& [state, weight] : histogram) {
     // fix markers scale ratio to ensure they can still be seen
     using std::max;
     const auto scale_factor = max(weight / max_bin_weight, 1e-1);  // or 1:10
     if (scale_factor < min_scale_factor) {
       min_scale_factor = scale_factor;
     }
  
     // use an inverted rainbow scale of decreasing opacity: bright red
     // for the most likely state and dim purple for the least likely one
     const auto vertex_color = detail::alphaHueToRGBA(
         static_cast<float>((1.0 - scale_factor) * 270.0), static_cast<float>(0.25 + 0.75 * scale_factor));
  
     // linearly scale arrow sizes using particle weights too
     arrow_bodies.points.push_back(tf2::toMsg(state * (scale_factor * arrow_body_base)));
     arrow_bodies.points.push_back(tf2::toMsg(state * (scale_factor * arrow_head_base)));
     arrow_bodies.colors.insert(arrow_bodies.colors.end(), 2, vertex_color);
  
     arrow_heads.points.push_back(tf2::toMsg(state * (scale_factor * arrow_head_left_corner)));
     arrow_heads.points.push_back(tf2::toMsg(state * (scale_factor * arrow_head_right_corner)));
     arrow_heads.points.push_back(tf2::toMsg(state * (scale_factor * arrow_head_tip)));
  
     arrow_heads.colors.insert(arrow_heads.colors.end(), 3, vertex_color);
   }
  
   arrow_bodies.scale.x = static_cast<double>(min_scale_factor * kArrowHeadWidth) * 0.8;
  
   return message;
 }
  
  
 template <
     class Particles,
     class Particle = ranges::range_value_t<Particles>,
     class State = typename beluga::state_t<Particle>,
     class Scalar = typename State::Scalar>
 beluga_ros::msg::MarkerArray& assign_particle_cloud(Particles&& particles, beluga_ros::msg::MarkerArray& message) {
   constexpr auto kDefaultLinearResolution = Scalar{1e-3};   // ie. 1 mm
   constexpr auto kDefaultAngularResolution = Scalar{1e-3};  // ie. 0.05 degrees
   return assign_particle_cloud(
       std::forward<Particles>(particles), kDefaultLinearResolution, kDefaultAngularResolution, message);
 }
  
 }  // namespace beluga_ros
  
 #endif  // BELUGA_ROS_PARTICLE_CLOUD_HPP