Only import pycolmap in run_hloc (#3146)

* remove pycolmap import on windows

* only import when run hloc

* also for pixsfm

* fix

nerfstudio/process_data/hloc_utils.py

@@ -26,29 +26,6 @@
 from nerfstudio.process_data.process_data_utils import CameraModel
 from nerfstudio.utils.rich_utils import CONSOLE
 
-try:
- # TODO(1480) un-hide pycolmap import
- import pycolmap
- from hloc import ( # type: ignore
- extract_features,
- match_features,
- pairs_from_exhaustive,
- pairs_from_retrieval,
- reconstruction,
- )
-except ImportError:
- _HAS_HLOC = False
-
-else:
- _HAS_HLOC = True
-
-try:
- from pixsfm.refine_hloc import PixSfM # type: ignore
-except ImportError:
- _HAS_PIXSFM = False
-else:
- _HAS_PIXSFM = True
-
 
 def run_hloc(
  image_dir: Path,
@@ -88,6 +65,29 @@ def run_hloc(
  refine_pixsfm: If True, refine the reconstruction using pixel-perfect-sfm.
  use_single_camera_mode: If True, uses one camera for all frames. Otherwise uses one camera per frame.
  """
+
+ try:
+ # TODO(1480) un-hide pycolmap import
+ import pycolmap
+ from hloc import ( # type: ignore
+ extract_features,
+ match_features,
+ pairs_from_exhaustive,
+ pairs_from_retrieval,
+ reconstruction,
+ )
+ except ImportError:
+ _HAS_HLOC = False
+ else:
+ _HAS_HLOC = True
+
+ try:
+ from pixsfm.refine_hloc import PixSfM # type: ignore
+ except ImportError:
+ _HAS_PIXSFM = False
+ else:
+ _HAS_PIXSFM = True
+
  if not _HAS_HLOC:
  CONSOLE.print(
  f"[bold red]Error: To use this set of parameters ({feature_type}/{matcher_type}/hloc), "