Unify camera model into immutable factory-built type

src/rpt/__init__.py

@@ -19,6 +19,7 @@ from ._core import (
     TriangulationTrace,
     build_pair_candidates,
     filter_pairs_with_previous_poses,
+    make_camera,
     triangulate_debug,
     triangulate_poses,
 )
@@ -80,6 +81,7 @@ __all__ = [
     "build_pair_candidates",
     "convert_cameras",
     "filter_pairs_with_previous_poses",
+    "make_camera",
     "make_triangulation_config",
     "pack_poses_2d",
     "triangulate_debug",

src/rpt/_helpers.py

@@ -6,7 +6,7 @@ from typing import Literal, TypeAlias, TypedDict
 import numpy as np
 import numpy.typing as npt
 
-from ._core import Camera, CameraModel, TriangulationConfig, TriangulationOptions
+from ._core import Camera, CameraModel, TriangulationConfig, TriangulationOptions, make_camera
 
 Matrix3x3Like: TypeAlias = Sequence[Sequence[float]]
 VectorLike: TypeAlias = Sequence[float]
@@ -64,17 +64,19 @@ def convert_cameras(cameras: Sequence[CameraLike]) -> list[Camera]:
             converted.append(cam)
             continue
 
-        camera = Camera()
-        camera.name = str(cam["name"])
-        camera.K = cam["K"]
         camera_model = _coerce_camera_model(cam.get("model", cam.get("type", "pinhole")))
-        camera.DC = _coerce_distortion(cam["DC"], camera_model)
-        camera.R = cam["R"]
-        camera.T = cam["T"]
-        camera.width = int(cam["width"])
-        camera.height = int(cam["height"])
-        camera.model = camera_model
-        converted.append(camera)
+        converted.append(
+            make_camera(
+                str(cam["name"]),
+                cam["K"],
+                _coerce_distortion(cam["DC"], camera_model),
+                cam["R"],
+                cam["T"],
+                int(cam["width"]),
+                int(cam["height"]),
+                camera_model,
+            )
+        )
     return converted