OpenCalib/CalibAnything

CalibAnything

This package provides an automatic and target-less LiDAR-camera extrinsic calibration method using Segment Anything Model. The related paper is Calib-Anything: Zero-training LiDAR-Camera Extrinsic Calibration Method Using Segment Anything. For more calibration codes, please refer to the link SensorsCalibration.

Prerequisites

pcl 1.10
opencv
eigen 3

Compile

git clone https://github.com/OpenCalib/CalibAnything.git
cd CalibAnything
# mkdir build
mkdir -p build && cd build
# build
cmake .. && make

Run Example

We provide examples of two dataset. You can download the processed data at Google Drive or BaiduNetDisk:

# baidunetdisk
Link: https://pan.baidu.com/s/1qAt7nYw5hYoJ1qrH0JosaQ?pwd=417d 
Code: 417d

Run the command:

cd CalibAnything
./bin/run_lidar2camera ./data/kitti/calib.json # kitti dataset
./bin/run_lidar2camera ./data/nuscenes/calib.json # nuscenes dataset

Test your own data

Data collection

Several pairs of time synchronized RGB images and LiDAR point cloud (intensity is needed). One pair of data can also be used to calibrate, but the results may be ubstable.
The intrinsic of the camera and the initial guess of the extrinsic.

Preprocessing

Generate masks

Follow the instructions in Segment Anything and generate masks of your image.

First download a model checkpoint. You can choose vit-l.
Install SAM

# environment: python>=3.8, pytorch>=1.7, torchvision>=0.8

git clone git@github.com:facebookresearch/segment-anything.git
cd segment-anything; pip install -e .
pip install opencv-python pycocotools matplotlib onnxruntime onnx

python scripts/amg.py --checkpoint <path/to/checkpoint> --model-type <model_type> --input <image_or_folder> --output <path/to/output>

# example(recommend parameter)
python scripts/amg.py --checkpoint sam_vit_l_0b3195.pth --model-type vit_l --input ./data/kitti/000000/images/  --output ./data/kitti/000000/masks/ --stability-score-thresh 0.9 --box-nms-thresh 0.5 --stability-score-offset 0.9

Data folder

The hierarchy of your folders should be formed as:

YOUR_DATA_FOLDER
├─calib.json
├─pc
|   ├─000000.pcd
|   ├─000001.pcd
|   ├─...
├─images
|   ├─000000.png
|   ├─000001.png
|   ├─...
├─masks
|   ├─000000
|   |   ├─000.png
|   |   ├─001.png
|   |   ├─...
|   ├─000001
|   ├─...

Processed masks

For large masks, we only use part of it near the edge.

python processed_mask.py -i <YOUR_DATA_FOLDER>/masks/ -o <YOUR_DATA_FOLDER>/processed_masks/

Edit the json file

Content description

cam_K: camera intrinsic matrix
cam_dist: camera distortion coefficient. [k1, k2, p1, p2, p3, ...], use the same order as opencv
T_lidar_to_cam: initial guess of the extrinsic
T_lidar_to_cam_gt: ground-truth of the extrinsic (Used to calculate error. If not provided, set "available" to false)
img_folder: the path to images
mask_folder: the path to masks
pc_folder: the path to point cloud
img_format: the suffix of the image
pc_format: the suffix of the point cloud (support pcd or kitti bin)
file_name: the name of the input images and point cloud
min_plane_point_num: the minimum number of point in plane extraction
cluster_tolerance: the spatial cluster tolerance in euclidean cluster (set larger if the point cloud is sparse, such as the 32-beam LiDAR)
search_num: the number of search times
search_range: the search range for rotation and translation
point_range: the approximate height range of the point cloud projected onto the image (the top of the image is 0.0 and the bottom of the image is 1.0)
down_sample: the point cloud downsample voxel size (if don't need downsample, set the "is_valid" to false)
thread: the number of thread to reduce calibration time

Calibration

./bin/run_lidar2camera <path-to-json-file>

Output

initial projection: init_proj.png, init_proj_seg.png
gt projection: gt_proj.png, gt_proj_seg.png
refined projection: refined_proj.png, refined_proj_seg.png
refined extrinsic: extrinsic.txt

Citation

If you find this project useful in your research, please consider cite:

@misc{luo2023calibanything,
      title={Calib-Anything: Zero-training LiDAR-Camera Extrinsic Calibration Method Using Segment Anything}, 
      author={Zhaotong Luo and Guohang Yan and Yikang Li},
      year={2023},
      eprint={2306.02656},
      archivePrefix={arXiv},
      primaryClass={cs.CV}
}

OpenCalib / CalibAnything