This is an extension of the incremental Structure-from-Motion framework COLMAP, allowing for the usage of Implicit Distortion camera model, which features a non-parametric generic representation of the calibration map and an adaptive partial calibration procedure. This is a cleaned up re-implementation of the original code used in the paper
Structure-from-Motion with a Non-Parametric Camera Model
Yihan Wang*, Linfei Pan*, Marc Pollefeys, Viktor Larsson
IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR) 2025
and if you have any problems running the code or find any bugs, please create an issue.
Please build GenSfM using the following commands:
mkdir build
cd build
cmake .. -GNinja
ninjaWe provide two example datasets that could be downloaded from here. Please download them and put them under data folder. Navigate to ./build/src/exe to run GenSfM.
If a COLMAP database already exists, GenSfM can directly use it to perform incremental mapping by:
./gen_colmap mapper \
--database_path ./data/CAB_facade_mixed/full_mix_centered.db \
--image_path ./data/CAB_facade_mixed/images \
--output_path ./data/CAB_facade_mixed/sparse \
# Add the following commands if you wish to monitor the middle stages of the reconstruction
--Mapper.snapshot_path ./data/CAB_facade_mixed/sparse/snapshot \
--Mapper.snapshot_images_freq 1If there is not a COLMAP database yet, you need to establish it first.
./gen_colmap feature_extractor \
--image_path ./data/Fisheye_grossmunster/images \
--database_path ./data/Fisheye_grossmunster/database.db \
# GenSFM could be ran by choosing IMPLICIT_DISTORTION camera model
--ImageReader.camera_model IMPLICIT_DISTORTION \
# Set the following argument if images are captured by the same camera per folder
--ImageReader.single_camera_per_folder 1
./gen_colmap exhaustive_matcher \
--database_path ./data/Fisheye_grossmunster/database.db \
--SiftMatching.multiple_models=1
./gen_colmap mapper \
--database_path ./data/Fisheye_grossmunster/database.db \
--image_path ./data/Fisheye_grossmunster/images \
--output_path ./data/Fisheye_grossmunster/sparse \
--Mapper.snapshot_path ./data/Fisheye_grossmunster/sparse/snapshot \
--Mapper.snapshot_images_freq 1We provide experimental scripts under experimental_scripts/cata_feature_matching to facilitate the feature matching for catadioptric images. To perform this, first run split_images.m to psuedo-undistort the catadioptric images into 8 rectangular views, and then use the following steps to perform feature merging and matching:
./gen_colmap feature_extractor --database_path database_split.db --image_path images_split/
./gen_colmap database_creator --database_path database.db
python merge_features.py database_split.db database.db 4288,2848,2190,1463,350,1250,796 # Change to the parameters obtained from `split_images.m`
./gen_colmap exhaustive_matcher --database_path database.db --SiftMatching.multiple_models=1
The results are written out in the COLMAP sparse reconstruction format. Please refer to COLMAP for more details. The reconstruction can be visualized using the GUI, for example:
./gen_colmap gui \
--database_path ./data/Fisheye_grossmunster/database.db \
--image_path ./data/Fisheye_grossmunster/images \
--import_path ./data/Fisheye_grossmunster/sparse/0We also provide scripts for undistorting fisheye or catadioptric images using the estimated calibration. Please first follow Implicit Distortion to install the dependencies.
Then, store the calibration spline control points {$\theta_i$, ./experimental_scripts/undistortion/test_data. Then see the notebook ./experimental_scripts/undistortion/test_undistortion.ipynb to run the undistortion.
This pipeline builds on COLMAP, RadialSfM, and Implicit_dst, for which you should cite:
@inproceedings{schoenberger2016sfm,
author={Sch\"{o}nberger, Johannes Lutz and Frahm, Jan-Michael},
title={Structure-from-Motion Revisited},
booktitle={Conference on Computer Vision and Pattern Recognition (CVPR)},
year={2016},
}
@inproceedings{schoenberger2016mvs,
author={Sch\"{o}nberger, Johannes Lutz and Zheng, Enliang and Pollefeys, Marc and Frahm, Jan-Michael},
title={Pixelwise View Selection for Unstructured Multi-View Stereo},
booktitle={European Conference on Computer Vision (ECCV)},
year={2016},
}
@inproceedings{larsson2020calibration,
title={Calibration-free structure-from-motion with calibrated radial trifocal tensors},
author={Larsson, Viktor and Zobernig, Nicolas and Taskin, Kasim and Pollefeys, Marc},
booktitle={European Conference on Computer Vision (ECCV)},
year={2020},
}
@inproceedings{pan2022camera,
title={Camera pose estimation using implicit distortion models},
author={Pan, Linfei and Pollefeys, Marc and Larsson, Viktor},
booktitle={Conference on Computer Vision and Pattern Recognition (CVPR)},
year={2022}
}