TRAVEL: Traversable Ground and Above-Ground Object Segmentation

Best Paper Award winner from RA-L 2022

Traversable Ground and Above-Ground Object Segmentation using Graph Representation for 3D LiDAR Scans.

(May 19, 2026) Python package is now available on PyPI

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🚀 Overview

Official page of "TRAVEL: Traversable Ground and Above-Ground Object Segmentation using Graph Representation for 3D LiDAR Scans", which is accepted by RA-L with IROS'22 option.

Keywords

Object segmentation, Traversable ground segmentation, Graph search, Autonomous navigation, LiDAR

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📂 Repository Layout

The repo is split so the algorithm core can be consumed without ROS or even without C++ tooling.

TRAVEL/
├── cpp/
│   ├── travel/        # Pure C++ core library (header-only). No ROS.
│   │   ├── core/travel/{tgs,aos,point_types,save_labels,kitti_loader,logging}.hpp
│   │   └── core/travel/3rdparty/nanoflann*.hpp
│   └── examples/      # Standalone CLI demo (run_travel_kitti). No ROS.
├── python/            # pip-installable bindings (travel-seg).
│   ├── pyproject.toml, CMakeLists.txt
│   └── travel_seg/    # numpy-friendly Python API on top of the C++ core
└── ros/               # ROS 2 (ament_cmake) wrapper that consumes cpp/travel/.
    └── src/travel_node.cpp, launch/, config/, rviz/

ROS 2 only. As of v1.0, the ros/ layer is ROS 2 (ament_cmake). The previous catkin / ROS 1 wrapper lives on at tag v0.1. Pin to that tag for Melodic / Noetic.

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🧪 Test Env.

• Algorithm core (cpp/): Ubuntu 20.04+, macOS 13+ (Apple Silicon / Intel) — needs only PCL + Boost.
• ROS 2 wrapper (ros/): verified on Humble (Ubuntu 22.04) and Jazzy (Ubuntu 24.04).

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🔨 How to Build

Python (pip)

pip install travel-seg

Prebuilt wheels are published for Linux x86_64 (manylinux), macOS arm64 + x86_64, and Windows x86_64 for CPython 3.8–3.13 — no system PCL / Boost install required since v1.1.

For development from a checkout:

# Ubuntu deps:  sudo apt install build-essential cmake libeigen3-dev
# macOS deps:   brew install cmake eigen
# Windows deps: vcpkg install eigen3:x64-windows

git clone https://github.com/url-kaist/TRAVEL.git
cd TRAVEL
pip install -e python/   # editable; rebuilds C++ on next import if changed

Quick start:

import numpy as np, travel_seg as ts
points = np.fromfile("0000.bin", dtype=np.float32).reshape(-1, 4)
result = ts.segment(points)            # SegmentResult
ground_pts = points[result.ground_mask]

See python/README.md for the full API.

Core library + standalone example (no ROS)

# Dependencies
# Ubuntu:  sudo apt install cmake libeigen3-dev libboost-all-dev libpcl-dev
# macOS:   brew install cmake eigen boost pcl

cmake -S cpp/travel -B build -DTRAVEL_BUILD_EXAMPLES=ON
cmake --build build -j

# Run the demo on a KITTI sequence
./build/examples/run_travel_kitti /path/to/kitti/sequences/00 0 /tmp/travel_out

ROS 2 wrapper

# Dependencies (Humble / Ubuntu 22.04; Jazzy / 24.04 substitutes 'humble' below)
sudo apt install build-essential cmake libeigen3-dev libpcl-dev \
                 libboost-system-dev libboost-filesystem-dev mpi-default-dev \
                 ros-humble-pcl-conversions

mkdir -p ros2_ws/src
cd ros2_ws/src
git clone https://github.com/url-kaist/TRAVEL.git
cd ..
source /opt/ros/humble/setup.bash
colcon build --packages-select travel_ros

Verified in CI on Humble (Ubuntu 22.04) and Jazzy (Ubuntu 24.04) via the official ros:humble / ros:jazzy Docker images.

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▶️ How to Run TRAVEL

source install/setup.bash
ros2 launch travel_ros travel_run.launch.py input_topic:=/your_lidar_topic

The node subscribes to ~/input (sensor_msgs/PointCloud2) and publishes ~/ground, ~/nonground, ~/labeled. All algorithm parameters are declared as ROS 2 node parameters; see ros/config/kitti_params.yaml.

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🔧 On your setting

1. Include travel/tgs.hpp and travel/aos.hpp from the cpp/travel/core include path.
2. Initialize travel::TravelGroundSeg<PointT> and travel::ObjectCluster<PointT>.
3. Use setParams() on each class to configure.
4. Use TravelGroundSeg::estimateGround() for traversable ground segmentation.
5. Use ObjectCluster::segmentObjects() for above-ground object segmentation.
6. Logging in the core is routed through TRAVEL_LOG_* macros (in travel/logging.hpp). Define TRAVEL_USE_ROS_LOGGING at compile time to dispatch to ROS_INFO/WARN/ERROR; otherwise output goes to stdout/stderr.

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🔗 Related

• pip install travel-seg is now supported via python/. See python/README.md.
• For the previous third-party Python wrapper, see https://github.com/darrenjkt/TRAVEL. Thank you Darren :)

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📄 Citation

If our research has been helpful, please cite the below papers:

@ARTICLE{oh2022travel,  
    author={Oh, Minho and Jung, Euigon and Lim, Hyungtae and Song, Wonho and Hu, Sumin and Lee, Eungchang Mason and Park, Junghee and Kim, Jaekyung and Lee, Jangwoo and Myung, Hyun},  
    journal={IEEE Robotics and Automation Letters},   
    title={TRAVEL: Traversable Ground and Above-Ground Object Segmentation Using Graph Representation of 3D LiDAR Scans},   
    volume={7},  
    number={3},  
    pages={7255-7262},  
    year={2022},
    }

@article{lim2021patchwork,
    title={Patchwork: Concentric Zone-based Region-wise Ground Segmentation with Ground Likelihood Estimation Using a 3D LiDAR Sensor},
    author={Lim, Hyungtae and Minho, Oh and Myung, Hyun},
    journal={IEEE Robot. Autom. Lett.},
    volume={6},
    number={4},
    pages={6458--6465},
    year={2021},
    }

@article{lim2021erasor,
    title={ERASOR: Egocentric Ratio of Pseudo Occupancy-Based Dynamic Object Removal for Static 3D Point Cloud Map Building},
    author={Lim, Hyungtae and Hwang, Sungwon and Myung, Hyun},
    journal={IEEE Robotics and Automation Letters},
    volume={6},
    number={2},
    pages={2272--2279},
    year={2021},
    publisher={IEEE}
    }