# ISCLOAM

## What is ISCLOAM?

- ISCLOAM presents a robust loop closure detection approach by integrating both geometry and intensity information.

## Repository Information

### Original Repository link

[https://github.com/wh200720041/iscloam](<https://github.com/wh200720041/iscloam>)

### Required Sensors

- LIDAR \[Velodyne\]

### ROS Compatibility

- ROS 1

### Dependencies

- Ubuntu 64-bit 20.04
- ROS Noetic [ROS Installation](<http://wiki.ros.org/ROS/Installation>)
- Ceres Solver [Ceres Installation](<https://github.com/ceres-solver/ceres-solver/blob/master/docs/source/installation.rst>)
- PCL [PCL Installation](<https://pointclouds.org/downloads/>)
- Gtsam [GTSAM Installation](<https://gtsam.org/get_started/>)
- OpenCV [OPENCV Installation](<https://opencv.org/releases/>)
- Trajectory visualization

For visualization purpose, this package uses hector trajectory sever, you may install the package by

```bash
sudo apt-get install ros-noetic-hector-trajectory-server
```

## Build and Run

### 1\. Clone repository

```bash
cd ~/catkin_ws/src
git clone https://github.com/wh200720041/iscloam.git
cd ..
catkin_make -j1
source ~/catkin_ws/devel/setup.bash
```

### 2\. Set Parameter

Change the bag location and sensor parameters on launch files.

### 3\. Launch

```bash
roslaunch iscloam iscloam.launch
```

if you would like to generate the map of environment at the same time, you can run

```bash
roslaunch iscloam iscloam_mapping.launch
```

Note that the global map can be very large, so it may takes a while to perform global optimization, some lag is expected between trajectory and map since they are running in separate thread. More CPU usage will happen when loop closure is identified.

## Example Result

Watch demo video at [Video Link](<https://youtu.be/Kfi6CFK4Ke4>)

### Ground Truth Comparison

Blue: ISCLOAM ("Visual Odometry" in the plot legend). Red: ground truth. The left plot shows KITTI sequence 00, and the right plot shows KITTI sequence 05.

## Citation

If you use this work for your research, you may want to cite the paper below, your citation will be appreciated

```bibtex
@inproceedings{wang2020intensity,
  author={H. {Wang} and C. {Wang} and L. {Xie}},
  booktitle={2020 IEEE International Conference on Robotics and Automation (ICRA)},
  title={Intensity Scan Context: Coding Intensity and Geometry Relations for Loop Closure Detection},
  year={2020},
  volume={},
  number={},
  pages={2095-2101},
  doi={10.1109/ICRA40945.2020.9196764}
}
```

## Acknowledgements

Thanks for [A-LOAM](<https://github.com/HKUST-Aerial-Robotics/A-LOAM>) and LOAM(J. Zhang and S. Singh. LOAM: Lidar Odometry and Mapping in Real-time) and [LOAM\_NOTED](<https://github.com/cuitaixiang/LOAM_NOTED>).

**Author:** [Wang Han](<http://wanghan.pro>), Nanyang Technological University, Singapore