eWand

This paper contains the code for the paper eWand: A calibration framework for wide baseline frame-based and event-based camera systems.

Citing

If you use this code in an academic context, please cite the following publication:

Paper: eWand: A calibration framework for wide baseline frame-based and event-based camera systems

Video: YouTube

Project: See here

@inproceedings{Gossard2024icra,
  url = {https://arxiv.org/pdf/2309.12685.pdf},
  title={eWand: A calibration framework for wide baseline frame-based and event-based camera systems},
  author={Gossard, Thomas and Ziegler, Andreas and Kolmar, Levin and Tebbe, Jonas and Zell, Andreas},
  year={2024},
  booktitle = {2024 {International} {Conference} on {Robotics} and {Automation} ({ICRA})},
  publisher = {IEEE},
}

Using the code

The code of this project is split into several packages:

• Marker extrection from frame-based cameras
• Marker extrection from event-based cameras
• A calibration framework consuming the extracted marker positions and optimizing the cameras' intrinsics and extrinsics

Marker extrection from frame-based cameras

Calibration framework

Software requirements

This code has been tested on Ubuntu 20.04.

Dependencies:

• OpenCV
• Ceres

How to build

1. Clone this repositories:

git clone https://github.com/cogsys-tuebingen/ewand

4. Build:

cd calibration_framework
mkdir build
cd build
cmake ..
make

5. Setup the intrinsic camera parameters

For every camera you want to calibrate, create a .yaml file with the following structure. You can get the intrinsic parameters from the intrinsic calibration tool of your choice, e.g. kalibr, OpenCV.

%YAML:1.0
camera_name: cam0
image_width: 1280
image_height: 1024
camera_matrix: !!opencv-matrix
  rows: 3
  cols: 3
  dt: d
  data: [1277.0348869354, 0, 637.71636909691, 0, 1276.78458195841, 488.458326168923, 0, 0, 1]
distortion_model: plumb_bob
distortion_coefficients: !!opencv-matrix
  rows: 1
  cols: 5
  dt: d
  data: [-0.220061443243291, 0.261537432483716, -0.0025783399940279, 0.00000095452629096082, 0]

6. Run:

cd buid
./src/wand_calibration_main \
  --cam1_config ../intrinsics/camera_0.yaml \
  --cam1_data ../data/camera_0.csv \
  --cam2_config ../intrinsics/camera_1.yaml \
  --cam2_data ../data/camera_1.csv \
  --cam3_config ../intrinsics/camera_2.yaml \
  --cam3_data ../data/camera_2.csv \
  --cam4_config ../intrinsics/camera_3.yaml \
  --cam4_data ../data/camera_3.csv \
  --cam5_config ../intrinsics/camera_4.yaml \
  --cam5_data ../data/camera_4.csv \
  --cam6_config ../intrinsics/camera_5.yaml \
  --cam6_data ../data/camera_5.csv \
  --wc_distance_scaling 1000 --wc_linearity_scaling 100000

where the yaml files contain the intrinsics of the cameras and the csv files the extracted markers from the frame- and event-based cameras.

Note: Use --help to see all the options.

License

This software is issued under the Apache License Version 2.0.