!!! This repository constains half-baked code that may not be well-maintained and not suitable for practical purposes. !!! !!! We don’t have resource to maintain this extension library. If you find an issue, please fix it by yourself and open a PR to share the solution. !!!

glim_ext

glim_ext is a set of extension modules for GLIM, 3D LiDAR mapping framework. With this package, we aim to provide reference implementations that demonstrate how GLIM can be extended through the global callback slot mechanism.

Disclaimer

Each module in glim_ext uses several external libraries that employ different licensing conditions. You must carefully check and follow their licenses.

Usage

To enable an extension module, add the so filename to extension_modules in glim/config/config_ros.json. E.g.,

"extension_modules": [
    "libmemory_monitor.so",
    "libstandard_viewer.so",
    "librviz_viewer.so",
    "libimu_validator.so"   // Added
  ],

Config path addressing

Extension modules first try to find the corresponding config path from config.json in the main GLIM package. It then fallback to config_ext.json in the glim_ext package if it failed to find a config path in config.json.

Example (libflat_earther.so):

1. Tries to find config_flat_earther in glim/config/config.json. The config path may be changed by config_path ROS param (see here).
2. If not found, find config_flat_earther in glim_ext/config/config_ext.json.

Example Modules

Callback demo (libglim_callback_demo.so)

• This modules subscribes to all available callbacks to demonstrate how mapping states can be retrieved

Odometry estimation Modules

Point cloud deskewing (libdeskewer.so)

• Publishing and saving deskewed point clouds (without downsampling).

IMU validator (libimu_validator.so)

• Validator for LiDAR-IMU transformation configurations.

IMU prediction (libimu_prediction.so)

• Publishing IMU-based state estimation at a high frequency for low-latency applications.

Gravity estimation (libgravity_estimator.so)

• Estimating the gravity vector in the sensor frame, and forcing the upward direction of the state estimation to be aligned with the gravity direction.

Velocity supressor (libvelocity_supressor.so)

• Regulating the velocity range.

ORB_SLAM odometry (Not Maintained)

• Loosely coupled visual odometry constraints based on ORB_SLAM3
• Dependency: ORB_SLAM3 (GPL-3.0)

Global Optimization Modules

Flat earther (libflat_earther.so)

• Forcing the height of proximiate submaps be the same.
• This is useful in situations only a single floor exists and the height of the sensor from the floor is mostly unchanged.

GNSS constraints (libgnss_global.so, ROS2 only)

• GNSS-based constraints for global optimization

ScanContext Loop Detector (libscancontext_loop_detector.so)

• Explicit loop detection based on ScanContext
• Dependency: ScanContext (CC BY-NC-SA 4.0)

DBoW Loop Detector (Not Maintained)

• Explicit loop detection based on DBoW3
• Dependency: DBoW3 (LICENSE)

Installation

ROS1

!!! We do not and will not support ROS1. While some modules would still work on ROS1, no tests are conducted. !!!

cd ~/catkin_ws/src
git clone https://github.com/koide3/glim_ext

cd ..
catkin_make -DCMAKE_BUILD_TYPE=Release

ROS2

```bash cd ~/ros2_ws/src git clone https://github.com/koide3/glim_ext

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