New inflation layer

configuration/packages/configuring-costmaps.rst

@@ -378,6 +378,7 @@ Plugin Parameters
 
   costmap-plugins/static.rst
   costmap-plugins/inflation.rst
+  costmap-plugins/inflation_legacy.rst
   costmap-plugins/obstacle.rst
   costmap-plugins/voxel.rst
   costmap-plugins/range.rst

configuration/packages/costmap-plugins/inflation.rst

@@ -64,3 +64,45 @@ This layer places an exponential decay functions around obstacles to increase co
 
   Description
     Whether to inflate unknown cells.
+
+
+:``<inflation layer>``.num_threads:
+
+  ==== =======
+  Type Default
+  ---- -------
+  int  -1
+  ==== =======
+
+  Description
+    Number of threads to use for inflation computation when OpenMP is enabled.
+    Set to ``-1`` for auto-detection (uses half of available CPU cores), or specify a positive integer for explicit thread count.
+    Ignored if OpenMP support is not available.
+
+Building with OpenMP
+--------------------
+
+OpenMP parallelization is disabled by default. To enable it, pass the ``ENABLE_OPENMP`` CMake option when building:
+
+.. code-block:: bash
+
+    # Build with OpenMP enabled
+    colcon build --packages-select nav2_costmap_2d --cmake-args -DENABLE_OPENMP=ON
+
+    # Build with OpenMP disabled (default)
+    colcon build --packages-select nav2_costmap_2d --cmake-args -DENABLE_OPENMP=OFF
+
+Performance Benchmarks
+----------------------
+
+**Test Configuration:** 2000×2000 Grid (4M cells, 50% occupancy, 2m inflation radius)
+
+**Robot Hardware:** 16 cores × 5000 MHz
+
++---------------------+----------+------------------+---------------------------+
+| Configuration       | Time     | Throughput       | vs Legacy Inflation Layer |
++=====================+==========+==================+===========================+
+| OpenMP disabled     | 48.9 ms  | 81.8 M cells/s   | 2.1× faster               |
++---------------------+----------+------------------+---------------------------+
+| OpenMP enabled      | 9.11 ms  | 468.9 M cells/s  | 11.5× faster              |
++---------------------+----------+------------------+---------------------------+

configuration/packages/costmap-plugins/inflation_legacy.rst

@@ -0,0 +1,70 @@
+.. inflation:
+
+Legacy Inflation Layer Parameters
+=================================
+
+.. warning::
+
+   This layer has been deprecated in favor of the refactored :doc:`Inflation Layer <inflation>`, which offers significantly improved performance (up to 11.5× faster with OpenMP enabled). Consider migrating to the new implementation.
+
+This layer places an exponential decay functions around obstacles to increase cost to traverse near collision. It also places a lethal cost around obstacles within the robot's fully inscribed radius - even if a robot is non-circular for optimized first-order collision checking.
+
+``<inflation layer>`` is the corresponding plugin name selected for this type.
+
+
+:``<inflation layer>``.enabled:
+
+  ==== =======
+  Type Default
+  ---- -------
+  bool True
+  ==== =======
+
+  Description
+    Whether it is enabled.
+
+:``<inflation layer>``.inflation_radius:
+
+  ====== =======
+  Type   Default
+  ------ -------
+  double 0.55
+  ====== =======
+
+  Description
+    Radius to inflate costmap around lethal obstacles.
+
+:``<inflation layer>``.cost_scaling_factor:
+
+  ====== =======
+  Type   Default
+  ------ -------
+  double 10.0
+  ====== =======
+
+  Description
+    Exponential decay factor across inflation radius.
+
+
+:``<inflation layer>``.inflate_unknown:
+
+  ==== =======
+  Type Default
+  ---- -------
+  bool False
+  ==== =======
+
+  Description
+    Whether to inflate unknown cells as if lethal.
+
+
+:``<inflation layer>``.inflate_around_unknown:
+
+  ==== =======
+  Type Default
+  ---- -------
+  bool False
+  ==== =======
+
+  Description
+    Whether to inflate unknown cells.

migration/Kilted.rst

@@ -825,3 +825,11 @@ Additionally, warnings have been added to the parameter handler to alert users o
 - When using a constant ``lookahead_dist``, a warning is emitted if ``min_distance_to_obstacle`` exceeds ``lookahead_dist``.
 
 A new parameter ``allow_obstacle_checking_beyond_goal`` (default: false) has also been added. By default, obstacle checking along the projected trajectory stops at the goal position (end of the path). When enabled, collision checking continues past the goal up to ``min_distance_to_obstacle``, regardless of the remaining path length. This parameter requires ``use_velocity_scaled_lookahead_dist`` to be enabled and ``min_distance_to_obstacle`` > 0.0.
+
+Refactored Inflation layer powered by OpenMP
+--------------------------------------------
+
+`PR #5933 <https://github.com/ros-navigation/navigation2/pull/5933>`_ refactors the Inflation layer to leverage OpenMP for parallel processing, significantly improving performance in large maps.
+
+The new implementation replaces the previous queue-based cell iteration with a Felzenszwalb-Huttenlocher distance transform algorithm.
+When OpenMP is not available at compile time, the layer falls back to single-threaded operation.

plugins/index.rst

@@ -51,7 +51,12 @@ Costmap Layers
 |                                |                        | occupancy information into       |
 |                                |                        | costmap                          |
 +--------------------------------+------------------------+----------------------------------+
-| `Inflation Layer`_             | Eitan Marder-Eppstein  | Inflates lethal obstacles in     |
+| `Inflation Layer`_             | Tony Najjar            | Inflates lethal obstacles in     |
+|                                |                        | costmap with exponential decay   |
+|                                |                        | (with the option to use OpenMP   |
+|                                |                        | for parallelization)             |
++--------------------------------+------------------------+----------------------------------+
+| `Legacy Inflation Layer`_      | Eitan Marder-Eppstein  | Inflates lethal obstacles in     |
 |                                |                        | costmap with exponential decay   |
 +--------------------------------+------------------------+----------------------------------+
 |  `Obstacle Layer`_             | Eitan Marder-Eppstein  | Maintains persistent 2D costmap  |
@@ -81,6 +86,7 @@ Costmap Layers
 .. _Static Layer: https://github.com/ros-navigation/navigation2/tree/main/nav2_costmap_2d/plugins/static_layer.cpp
 .. _Range Layer: https://github.com/ros-navigation/navigation2/tree/main/nav2_costmap_2d/plugins/range_sensor_layer.cpp
 .. _Inflation Layer: https://github.com/ros-navigation/navigation2/tree/main/nav2_costmap_2d/plugins/inflation_layer.cpp
+.. _Legacy Inflation Layer: https://github.com/ros-navigation/navigation2/tree/main/nav2_costmap_2d/plugins/legacy_inflation_layer.cpp
 .. _Obstacle Layer: https://github.com/ros-navigation/navigation2/tree/main/nav2_costmap_2d/plugins/obstacle_layer.cpp
 .. _Spatio-Temporal Voxel Layer: https://github.com/SteveMacenski/spatio_temporal_voxel_layer/
 .. _Non-Persistent Voxel Layer: https://github.com/SteveMacenski/nonpersistent_voxel_layer