Grid Mapping Plugin

The Grid Mapping plugin provides real-time terrain heightmap generation from depth cameras for locomotion and navigation.

Overview

The Grid Mapping plugin processes depth camera data to create terrain heightmaps:

• Real-time terrain elevation mapping

• Ray casting based depth data processing

• Hole filling for missing data interpolation

• Inpainting for terrain reconstruction

• Multi-sensor support

• Integration with RaiSim physics simulation

The plugin is essential for quadruped locomotion, providing terrain awareness for footstep planning and obstacle avoidance.

Dependencies

• D455 plugin (or other depth camera plugin)

• IEKF state estimator (or sim_state for simulation)

Configuration

Configuration File

Location: raisin_grid_mapping_plugin/config/params.yaml

rate: 500
heightmap_publish_rate: 5
map_resolution: 0.025
local_map_size: 10
max_count: 1
velocity_trust_threshold: 8.0
distance_threshold: 0.1
height_threshold_minimum: 0.05
height_threshold_proportional: 0.05

ray_casting:
  is_ray_casting: false
  downsampling_kernel: 20

hole_filling:
  is_hole_filling: true
  hole_filling_kernel_size: 5

inpainting:
  is_inpainting: false
  rayWidthProportional: 5.0

memorize_limit: 0.1

Parameter Reference

Map Configuration:

Parameter	Default	Description
rate	500	Processing rate (Hz)
heightmap_publish_rate	5	Heightmap publishing rate (Hz)
map_resolution	0.025	Map resolution in meters per cell
local_map_size	10	Local map size in meters

Trust and Filtering:

Parameter	Default	Description
velocity_trust_threshold	8.0	Maximum velocity for trusting measurements (m/s)
distance_threshold	0.1	Distance threshold for filtering (m)
height_threshold_minimum	0.05	Minimum height change threshold (m)
height_threshold_proportional	0.05	Height threshold increase per meter of distance

Ray Casting:

Parameter	Default	Description
is_ray_casting	false	Enable ray casting for occlusion handling
downsampling_kernel	20	Ray casting downsampling factor

Hole Filling:

Parameter	Default	Description
is_hole_filling	true	Enable hole filling for missing data
hole_filling_kernel_size	5	Kernel size for hole filling algorithm

Inpainting:

Parameter	Default	Description
is_inpainting	false	Enable inpainting for terrain reconstruction
rayWidthProportional	5.0	Ray width proportional factor for inpainting

Memory:

Parameter	Default	Description
memorize_limit	0.1	Time limit for keeping old measurements (seconds)

Message Topics

Publishers

Topic	Type	Description
/heightmap	raisin_interfaces/Heightmap	Processed terrain heightmap
/inpaint_heightmap	raisin_interfaces/Heightmap	Inpainted terrain heightmap

Subscribers

Topic	Type	Description
/pose	raisin_interfaces/Pose	Robot pose from state estimator
/joint_states	raisin_interfaces/JointStates	Joint states for leg collision filtering
/module_list	raisin_interfaces/ModuleList	Loaded module list for state estimator verification

Services

Service	Type	Description
/get_inpaintmap	GetInpaintmap	Request inpainted map data

Usage

Basic Setup

1. Load a supported depth camera plugin

2. Load a state estimator (IEKF or sim_state)

3. Load the Grid Mapping plugin

Example configuration in params.yaml:

plugin:
  raisin_d455_plugin:  # e.g., for D455 camera
    rate: 30

  raisin_iekf_plugin:
    rate: 400

  raisin_grid_mapping_plugin:
    rate: 500

Tuning for Different Terrains

For rough terrain:

height_threshold_minimum: 0.1

For smooth terrain:

height_threshold_minimum: 0.02

Note

Lower resolution (larger map_resolution) improves performance but reduces terrain detail.

Warning

Grid Mapping requires a valid state estimator. The plugin will wait until a valid estimator (iekf or sim_state) is loaded.