pycolmap.import_images() fails with TypeError due to WindowsPath object being passed instead of str

[sdnavin]

While running the ns-process-data command with --matcher-type NN-ratio, the process fails during the pycolmap.import_images() call. This happens because WindowsPath objects are passed instead of str, which pycolmap strictly requires.

📋 Command
ns-process-data images --data C:\Users\turbo\Videos\s4\recv3\360v2\images --output-dir my_scene --matcher-type NN-ratio

🧵 Full Traceback
Traceback (most recent call last):
File "", line 198, in _run_module_as_main
...
File "nerfstudio/hloc/hloc/reconstruction.py", line 45, in import_images
pycolmap.import_images(
TypeError: import_images(): incompatible function arguments. The following argument types are supported:
1. (database_path: str, image_path: str, camera_mode: pycolmap._core.CameraMode = CameraMode.AUTO, image_names: list[str] = [], options: pycolmap._core.ImageReaderOptions = ImageReaderOptions())

Invoked with: WindowsPath('my_scene/colmap/sparse/0/database.db'), WindowsPath('my_scene/images'), CameraMode.SINGLE; kwargs: image_list=[], options=ImageReaderOptions(...)

💡 Suggested Fix
In file:
nerfstudio/hloc/hloc/reconstruction.py
Line ~45 should cast paths to strings before passing them to pycolmap.import_images():

❌ Current:
pycolmap.import_images(
database,
image_dir,
camera_mode,
image_names=image_list,
options=image_options,
)
✅ Suggested Fix:
pycolmap.import_images(
str(database),
str(image_dir),
camera_mode,
image_names=image_list,
options=image_options,
)
🧪 Environment
OS: Windows 10
Python: 3.10
Nerfstudio version: latest (as of July 14, 2025)
Installed via: pip in virtualenv
pycolmap version: 0.6.0
ns-process-data used with --matcher-type NN-ratio

[tommybotch]

I also had this happen -- downgrading to pycolmap==0.4.0 worked for me. However I think the suggested fix would be a better solution (allowing use of newer versions of COLMAP)