From 2727741b98004e8233804b2353cde6564f7e4f25 Mon Sep 17 00:00:00 2001
From: roomrys <38435167+roomrys@users.noreply.github.com>
Date: Mon, 18 Nov 2024 12:43:42 -0800
Subject: [PATCH 1/8] Create Camera class with basic attributes

---
 sleap_io/model/camera.py | 77 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 77 insertions(+)
 create mode 100644 sleap_io/model/camera.py

diff --git a/sleap_io/model/camera.py b/sleap_io/model/camera.py
new file mode 100644
index 00000000..2edb1d74
--- /dev/null
+++ b/sleap_io/model/camera.py
@@ -0,0 +1,77 @@
+"""Data structure for a single camera view in a multi-camera setup."""
+
+from __future__ import annotations
+
+import attrs
+import numpy as np
+from attrs import define, field
+
+
+@define
+class Camera:
+    """A camera used to record in a multi-view `RecordingSession`.
+
+    Attributes:
+        matrix: Intrinsic camera matrix of size 3 x 3.
+        dist: Radial-tangential distortion coefficients [k_1, k_2, p_1, p_2, k_3].
+        size: Image size.
+        rvec: Rotation vector in unnormalized axis-angle representation of size 3.
+        tvec: Translation vector of size 3.
+        name: Camera name.
+    """
+
+    matrix: np.ndarray = field(
+        default=np.eye(3),
+        converter=np.array,
+    )
+    dist: np.ndarray = field(
+        default=np.zeros(5), converter=lambda x: np.array(x).ravel()
+    )
+    size: tuple[int, int] = field(
+        default=None, converter=attrs.converters.optional(tuple)
+    )
+    rvec: np.ndarray = field(
+        default=np.zeros(3), converter=lambda x: np.array(x).ravel()
+    )
+    tvec: np.ndarray = field(
+        default=np.zeros(3), converter=lambda x: np.array(x).ravel()
+    )
+    name: str = field(default=None, converter=attrs.converters.optional(str))
+
+    @matrix.validator
+    @dist.validator
+    @size.validator
+    @rvec.validator
+    @tvec.validator
+    def _validate_shape(self, attribute: attrs.Attribute, value):
+        """Validate shape of attribute based on metadata.
+
+        Args:
+            attribute: Attribute to validate.
+            value: Value of attribute to validate.
+
+        Raises:
+            ValueError: If attribute shape is not as expected.
+        """
+
+        # Define metadata for each attribute
+        attr_metadata = {
+            "matrix": {"shape": (3, 3), "type": np.ndarray},
+            "dist": {"shape": (5,), "type": np.ndarray},
+            "size": {"shape": (2,), "type": tuple},
+            "rvec": {"shape": (3,), "type": np.ndarray},
+            "tvec": {"shape": (3,), "type": np.ndarray},
+        }
+        optional_attrs = ["size"]
+
+        # Skip validation if optional attribute is None
+        if attribute.name in optional_attrs and value is None:
+            return
+
+        # Validate shape of attribute
+        expected_shape = attr_metadata[attribute.name]["shape"]
+        expected_type = attr_metadata[attribute.name]["type"]
+        if np.shape(value) != expected_shape:
+            raise ValueError(
+                f"{attribute.name} must be a {expected_type} of size {expected_shape}"
+            )

From 30aecee55f791d5e2947cb4fa1bea7624df5cc61 Mon Sep 17 00:00:00 2001
From: roomrys <38435167+roomrys@users.noreply.github.com>
Date: Mon, 18 Nov 2024 12:44:30 -0800
Subject: [PATCH 2/8] Test Camera's core attributes

---
 tests/model/test_camera.py | 122 +++++++++++++++++++++++++++++++++++++
 1 file changed, 122 insertions(+)
 create mode 100644 tests/model/test_camera.py

diff --git a/tests/model/test_camera.py b/tests/model/test_camera.py
new file mode 100644
index 00000000..34183866
--- /dev/null
+++ b/tests/model/test_camera.py
@@ -0,0 +1,122 @@
+"""Tests for methods in the sleap_io.model.instance file."""
+
+import numpy as np
+import pytest
+
+from sleap_io.model.camera import Camera
+
+
+def test_camera_name():
+    """Test camera name converter always converts to string."""
+
+    # During initialization
+    camera = Camera(name=12)
+    assert camera.name == "12"
+
+    # After initialization
+    camera = Camera()
+    assert camera.name is None
+    camera.name = 12
+    assert camera.name == "12"
+    camera.name = "12"
+    assert camera.name == "12"
+
+
+def test_camera_matrix():
+    """Test camera matrix converter and validator."""
+
+    matrix_list = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
+    matrix_array = np.array(matrix_list)
+
+    # During initialization
+    camera = Camera(matrix=matrix_list)
+    np.testing.assert_array_equal(camera.matrix, matrix_array)
+    with pytest.raises(ValueError):
+        camera = Camera(matrix=[[1, 2], [3, 4]])
+
+    # Test matrix converter
+    camera = Camera()
+    camera.matrix = matrix_list
+    np.testing.assert_array_equal(camera.matrix, matrix_array)
+    matrix_array = np.array(matrix_list)
+    camera.matrix = matrix_array
+    np.testing.assert_array_equal(camera.matrix, matrix_array)
+    with pytest.raises(ValueError):
+        camera.matrix = [[1, 2], [3, 4]]
+
+
+def test_camera_distortions():
+    """Test camera distortion converter and validator."""
+
+    distortions_unraveled = [[1], [2], [3], [4], [5]]
+    distortions_raveled = np.array(distortions_unraveled).ravel()
+
+    # During initialization
+    camera = Camera(dist=distortions_unraveled)
+    np.testing.assert_array_equal(camera.dist, distortions_raveled)
+    with pytest.raises(ValueError):
+        camera = Camera(dist=distortions_raveled[:3])
+
+    # Test distortion converter
+    camera = Camera()
+    camera.dist = distortions_unraveled
+    np.testing.assert_array_equal(camera.dist, distortions_raveled)
+    with pytest.raises(ValueError):
+        camera.dist = distortions_raveled[:3]
+
+
+def test_camera_size():
+    """Test camera size converter and validator."""
+
+    size = (100, 200)
+
+    # During initialization
+    camera = Camera(size=size)
+    assert camera.size == size
+    with pytest.raises(ValueError):
+        camera = Camera(size=(100, 200, 300))
+
+    # Test size converter
+    camera = Camera()
+    camera.size = size
+    assert camera.size == size
+    with pytest.raises(ValueError):
+        camera.size = (100, 200, 300)
+
+
+def test_camera_rvec():
+    """Test camera rotation vector converter and validator."""
+
+    rvec = [1, 2, 3]
+
+    # During initialization
+    camera = Camera(rvec=rvec)
+    np.testing.assert_array_equal(camera.rvec, rvec)
+    with pytest.raises(ValueError):
+        camera = Camera(rvec=[1, 2])
+
+    # Test rvec validator
+    camera = Camera()
+    camera.rvec = rvec
+    np.testing.assert_array_equal(camera.rvec, rvec)
+    with pytest.raises(ValueError):
+        camera.rvec = [1, 2]
+
+
+def test_camera_tvec():
+    """Test camera translation vector converter and validator."""
+
+    tvec = [1, 2, 3]
+
+    # During initialization
+    camera = Camera(tvec=tvec)
+    np.testing.assert_array_equal(camera.tvec, tvec)
+    with pytest.raises(ValueError):
+        camera = Camera(tvec=[1, 2])
+
+    # Test tvec validator
+    camera = Camera()
+    camera.tvec = tvec
+    np.testing.assert_array_equal(camera.tvec, tvec)
+    with pytest.raises(ValueError):
+        camera.tvec = [1, 2]

From c582bfd540283bc5474020d0157e1bceef19345b Mon Sep 17 00:00:00 2001
From: roomrys <38435167+roomrys@users.noreply.github.com>
Date: Wed, 20 Nov 2024 09:52:35 -0800
Subject: [PATCH 3/8] Add extrinsic_matrix, undistort, and project

---
 sleap_io/model/camera.py | 185 +++++++++++++++++++++++++++++++++++----
 1 file changed, 169 insertions(+), 16 deletions(-)

diff --git a/sleap_io/model/camera.py b/sleap_io/model/camera.py
index 2edb1d74..8c902238 100644
--- a/sleap_io/model/camera.py
+++ b/sleap_io/model/camera.py
@@ -3,6 +3,7 @@
 from __future__ import annotations
 
 import attrs
+import cv2
 import numpy as np
 from attrs import define, field
 
@@ -12,37 +13,42 @@ class Camera:
     """A camera used to record in a multi-view `RecordingSession`.
 
     Attributes:
-        matrix: Intrinsic camera matrix of size 3 x 3.
-        dist: Radial-tangential distortion coefficients [k_1, k_2, p_1, p_2, k_3].
-        size: Image size.
-        rvec: Rotation vector in unnormalized axis-angle representation of size 3.
-        tvec: Translation vector of size 3.
+        matrix: Intrinsic camera matrix of size (3, 3) and type float64.
+        dist: Radial-tangential distortion coefficients [k_1, k_2, p_1, p_2, k_3] of
+            size (5,) and type float64.
+        size: Image size of camera in pixels of size (2,) and type int.
+        rvec: Rotation vector in unnormalized axis-angle representation of size (3,) and
+            type float64.
+        tvec: Translation vector of size (3,) and type float64.
+        extrinsic_matrix: Extrinsic matrix of camera of size (4, 4) and type float64.
         name: Camera name.
     """
 
     matrix: np.ndarray = field(
         default=np.eye(3),
-        converter=np.array,
+        converter=lambda x: np.array(x, dtype="float64"),
     )
     dist: np.ndarray = field(
-        default=np.zeros(5), converter=lambda x: np.array(x).ravel()
+        default=np.zeros(5), converter=lambda x: np.array(x, dtype="float64").ravel()
     )
     size: tuple[int, int] = field(
         default=None, converter=attrs.converters.optional(tuple)
     )
-    rvec: np.ndarray = field(
-        default=np.zeros(3), converter=lambda x: np.array(x).ravel()
+    _rvec: np.ndarray = field(
+        default=np.zeros(3), converter=lambda x: np.array(x, dtype="float64").ravel()
     )
-    tvec: np.ndarray = field(
-        default=np.zeros(3), converter=lambda x: np.array(x).ravel()
+    _tvec: np.ndarray = field(
+        default=np.zeros(3), converter=lambda x: np.array(x, dtype="float64").ravel()
     )
     name: str = field(default=None, converter=attrs.converters.optional(str))
+    _extrinsic_matrix: np.ndarray = field(init=False)
 
     @matrix.validator
     @dist.validator
     @size.validator
-    @rvec.validator
-    @tvec.validator
+    @_rvec.validator
+    @_tvec.validator
+    @_extrinsic_matrix.validator
     def _validate_shape(self, attribute: attrs.Attribute, value):
         """Validate shape of attribute based on metadata.
 
@@ -59,8 +65,9 @@ def _validate_shape(self, attribute: attrs.Attribute, value):
             "matrix": {"shape": (3, 3), "type": np.ndarray},
             "dist": {"shape": (5,), "type": np.ndarray},
             "size": {"shape": (2,), "type": tuple},
-            "rvec": {"shape": (3,), "type": np.ndarray},
-            "tvec": {"shape": (3,), "type": np.ndarray},
+            "_rvec": {"shape": (3,), "type": np.ndarray},
+            "_tvec": {"shape": (3,), "type": np.ndarray},
+            "_extrinsic_matrix": {"shape": (4, 4), "type": np.ndarray},
         }
         optional_attrs = ["size"]
 
@@ -73,5 +80,151 @@ def _validate_shape(self, attribute: attrs.Attribute, value):
         expected_type = attr_metadata[attribute.name]["type"]
         if np.shape(value) != expected_shape:
             raise ValueError(
-                f"{attribute.name} must be a {expected_type} of size {expected_shape}"
+                f"{attribute.name} must be a {expected_type} of size {expected_shape}, "
+                f"but recieved shape: {np.shape(value)} and type: {type(value)} for "
+                f"value: {value}"
             )
+
+    def __attrs_post_init__(self):
+        """Initialize extrinsic matrix from rotation and translation vectors."""
+
+        # Initialize extrinsic matrix
+        self._extrinsic_matrix = np.eye(4, dtype="float64")
+        self._extrinsic_matrix[:3, :3] = cv2.Rodrigues(self._rvec)[0]
+        self._extrinsic_matrix[:3, 3] = self._tvec
+
+    @property
+    def rvec(self) -> np.ndarray:
+        """Get rotation vector of camera.
+
+        Returns:
+            Rotation vector of camera of size 3.
+        """
+
+        return self._rvec
+
+    @rvec.setter
+    def rvec(self, value: np.ndarray):
+        """Set rotation vector and update extrinsic matrix.
+
+        Args:
+            value: Rotation vector of size 3.
+        """
+        self._rvec = value
+
+        # Update extrinsic matrix
+        rotation_matrix, _ = cv2.Rodrigues(self._rvec)
+        self._extrinsic_matrix[:3, :3] = rotation_matrix
+
+    @property
+    def tvec(self) -> np.ndarray:
+        """Get translation vector of camera.
+
+        Returns:
+            Translation vector of camera of size 3.
+        """
+
+        return self._tvec
+
+    @tvec.setter
+    def tvec(self, value: np.ndarray):
+        """Set translation vector and update extrinsic matrix.
+
+        Args:
+            value: Translation vector of size 3.
+        """
+
+        self._tvec = value
+
+        # Update extrinsic matrix
+        self._extrinsic_matrix[:3, 3] = self._tvec
+
+    @property
+    def extrinsic_matrix(self) -> np.ndarray:
+        """Get extrinsic matrix of camera.
+
+        Returns:
+            Extrinsic matrix of camera of size 4 x 4.
+        """
+
+        return self._extrinsic_matrix
+
+    @extrinsic_matrix.setter
+    def extrinsic_matrix(self, value: np.ndarray):
+        """Set extrinsic matrix and update rotation and translation vectors.
+
+        Args:
+            value: Extrinsic matrix of size 4 x 4.
+        """
+
+        self._extrinsic_matrix = value
+
+        # Update rotation and translation vectors
+        self._rvec, _ = cv2.Rodrigues(self._extrinsic_matrix[:3, :3])
+        self._tvec = self._extrinsic_matrix[:3, 3]
+
+    def undistort_points(self, points: np.ndarray) -> np.ndarray:
+        """Undistort points using camera matrix and distortion coefficients.
+
+        Args:
+            points: Points to undistort of shape (N, 2).
+
+        Returns:
+            Undistorted points of shape (N, 2).
+        """
+
+        shape = points.shape
+        points = points.reshape(-1, 1, 2)
+        out = cv2.undistortPoints(points, self.matrix, self.dist)
+        return out.reshape(shape)
+
+    def project(self, points: np.ndarray) -> np.ndarray:
+        """Project 3D points to 2D using camera matrix and distortion coefficients.
+
+        Args:
+            points: 3D points to project of shape (N, 3) or (N, 1, 3).
+
+        Returns:
+            Projected 2D points of shape (N, 1, 2).
+        """
+
+        points = points.reshape(-1, 1, 3)
+        out, _ = cv2.projectPoints(
+            points,
+            self.rvec,
+            self.tvec,
+            self.matrix,
+            self.dist,
+        )
+        return out
+
+    # TODO: Remove this when we implement triangulation without aniposelib
+    def __getattr__(self, name: str):
+        """Get attribute by name.
+
+        Args:
+            name: Name of attribute to get.
+
+        Returns:
+            Value of attribute.
+
+        Raises:
+            AttributeError: If attribute does not exist.
+        """
+
+        if name in self.__attrs_attrs__:
+            return getattr(self, name)
+
+        # The aliases for methods called when triangulate with sleap_anipose
+        method_aliases = {
+            "get_name": self.name,
+            "get_extrinsic_matrix": self.extrinsic_matrix,
+        }
+
+        def return_callable_method_alias():
+            return method_aliases[name]
+
+        if name in method_aliases:
+            return return_callable_method_alias
+
+        raise AttributeError(f"'Camera' object has no attribute or method '{name}'")

From de1728e4ee7ecc224f78097f2a934e415a66311f Mon Sep 17 00:00:00 2001
From: roomrys <38435167+roomrys@users.noreply.github.com>
Date: Wed, 20 Nov 2024 09:53:09 -0800
Subject: [PATCH 4/8] Add tests for extrinisic_matrix, undistort, project,and
 aliases

---
 tests/model/test_camera.py | 143 +++++++++++++++++++++++++++++++++++++
 1 file changed, 143 insertions(+)

diff --git a/tests/model/test_camera.py b/tests/model/test_camera.py
index 34183866..db70779d 100644
--- a/tests/model/test_camera.py
+++ b/tests/model/test_camera.py
@@ -1,5 +1,6 @@
 """Tests for methods in the sleap_io.model.instance file."""
 
+import cv2
 import numpy as np
 import pytest
 
@@ -84,6 +85,25 @@ def test_camera_size():
         camera.size = (100, 200, 300)
 
 
+def construct_extrinsic_matrix(rvec, tvec):
+    """Construct extrinsic matrix from rotation and translation vectors.
+
+    Args:
+        rvec: Rotation vector in unnormalized axis angle representation of size (3,) and
+            type float64.
+        tvec: Translation vector of size (3,) and type float64.
+
+    Returns:
+        Extrinsic matrix of camera of size (4, 4) and type float64.
+    """
+
+    extrinsic_matrix = np.eye(4)
+    extrinsic_matrix[:3, :3] = cv2.Rodrigues(np.array(rvec))[0]
+    extrinsic_matrix[:3, 3] = tvec
+
+    return extrinsic_matrix
+
+
 def test_camera_rvec():
     """Test camera rotation vector converter and validator."""
 
@@ -92,15 +112,28 @@ def test_camera_rvec():
     # During initialization
     camera = Camera(rvec=rvec)
     np.testing.assert_array_equal(camera.rvec, rvec)
+    extrinsic_matrix = construct_extrinsic_matrix(camera.rvec, camera.tvec)
+    np.testing.assert_array_equal(camera.extrinsic_matrix, extrinsic_matrix)
+    np.testing.assert_array_equal(
+        camera.extrinsic_matrix[:3, :3], cv2.Rodrigues(camera.rvec)[0]
+    )
     with pytest.raises(ValueError):
         camera = Camera(rvec=[1, 2])
+    np.testing.assert_array_equal(camera.rvec, rvec)
+    np.testing.assert_array_equal(camera.extrinsic_matrix, extrinsic_matrix)
 
     # Test rvec validator
     camera = Camera()
     camera.rvec = rvec
     np.testing.assert_array_equal(camera.rvec, rvec)
+    np.testing.assert_array_equal(camera.extrinsic_matrix, extrinsic_matrix)
+    np.testing.assert_array_equal(
+        camera.extrinsic_matrix[:3, :3], cv2.Rodrigues(camera.rvec)[0]
+    )
     with pytest.raises(ValueError):
         camera.rvec = [1, 2]
+    np.testing.assert_array_equal(camera.rvec, rvec)
+    np.testing.assert_array_equal(camera.extrinsic_matrix, extrinsic_matrix)
 
 
 def test_camera_tvec():
@@ -111,12 +144,122 @@ def test_camera_tvec():
     # During initialization
     camera = Camera(tvec=tvec)
     np.testing.assert_array_equal(camera.tvec, tvec)
+    extrinsic_matrix = construct_extrinsic_matrix(camera.rvec, camera.tvec)
+    np.testing.assert_array_equal(camera.extrinsic_matrix, extrinsic_matrix)
+    np.testing.assert_array_equal(camera.extrinsic_matrix[:3, 3], camera.tvec)
     with pytest.raises(ValueError):
         camera = Camera(tvec=[1, 2])
+    np.testing.assert_array_equal(camera.tvec, tvec)
+    np.testing.assert_array_equal(camera.extrinsic_matrix, extrinsic_matrix)
 
     # Test tvec validator
     camera = Camera()
     camera.tvec = tvec
     np.testing.assert_array_equal(camera.tvec, tvec)
+    extrinsic_matrix = construct_extrinsic_matrix(camera.rvec, camera.tvec)
+    np.testing.assert_array_equal(camera.extrinsic_matrix, extrinsic_matrix)
+    np.testing.assert_array_equal(camera.extrinsic_matrix[:3, 3], camera.tvec)
     with pytest.raises(ValueError):
         camera.tvec = [1, 2]
+    np.testing.assert_array_equal(camera.tvec, tvec)
+    np.testing.assert_array_equal(camera.extrinsic_matrix, extrinsic_matrix)
+
+
+def test_camera_extrinsic_matrix():
+    """Test camera extrinsic matrix method."""
+
+    # During initialization
+
+    # ... with rvec and tvec
+    camera = Camera(
+        rvec=[1, 2, 3],
+        tvec=[1, 2, 3],
+    )
+    extrinsic_matrix = camera.extrinsic_matrix
+    np.testing.assert_array_equal(
+        extrinsic_matrix[:3, :3], cv2.Rodrigues(camera.rvec)[0]
+    )
+    np.testing.assert_array_equal(extrinsic_matrix[:3, 3], camera.tvec)
+
+    # ... without rvec and tvec
+    camera = Camera()
+    extrinsic_matrix = camera.extrinsic_matrix
+    np.testing.assert_array_equal(extrinsic_matrix, np.eye(4))
+
+    # After initialization
+
+    # Setting extrinsic matrix updates rvec and tvec
+    extrinsic_matrix = np.random.rand(4, 4)
+    camera.extrinsic_matrix = extrinsic_matrix
+    rvec = cv2.Rodrigues(camera.extrinsic_matrix[:3, :3])[0]
+    tvec = camera.extrinsic_matrix[:3, 3]
+    np.testing.assert_array_equal(camera.rvec, rvec.ravel())
+    np.testing.assert_array_equal(camera.tvec, tvec)
+
+    # Invalid extrinsic matrix doesn't update rvec and tvec or extrinsic matrix
+    with pytest.raises(ValueError):
+        camera.extrinsic_matrix = np.eye(3)
+    np.testing.assert_array_equal(camera.extrinsic_matrix, extrinsic_matrix)
+    np.testing.assert_array_equal(camera.rvec, rvec.ravel())
+    np.testing.assert_array_equal(camera.tvec, tvec)
+
+
+# TODO: Remove when implement triangulation without aniposelib
+def test_camera_aliases():
+    """Test camera aliases for attributes."""
+
+    camera = Camera(
+        matrix=[[1, 2, 3], [4, 5, 6], [7, 8, 9]],
+        dist=[[1], [2], [3], [4], [5]],
+        size=(100, 200),
+        rvec=[1, 2, 3],
+        tvec=[1, 2, 3],
+        name="camera",
+    )
+
+    # Test __getattr__ aliases
+    assert camera.get_name() == camera.name
+    np.testing.assert_array_equal(
+        camera.get_extrinsic_matrix(), camera.extrinsic_matrix
+    )
+
+
+def test_camera_undistort_points():
+    """Test camera undistort points method."""
+
+    camera = Camera(
+        matrix=[[1, 0, 0], [0, 1, 0], [0, 0, 1]],
+        dist=[[0], [0], [0], [0], [0]],
+    )
+
+    # Test with no distortion
+    points = np.array([[0, 0], [1, 1], [2, 2]], dtype=np.float32)
+    undistorted_points = camera.undistort_points(points)
+    np.testing.assert_array_equal(points, undistorted_points)
+
+    # Test with distortion
+    camera.dist = [[1], [0], [0], [0], [0]]
+    undistorted_points = camera.undistort_points(points)
+    with pytest.raises(AssertionError):
+        np.testing.assert_array_equal(points, undistorted_points)
+
+
+def test_camera_project():
+    """Test camera project method."""
+
+    camera = Camera(
+        matrix=[[1, 0, 0], [0, 1, 0], [0, 0, 1]],
+        dist=[[0], [0], [0], [0], [0]],
+    )
+
+    points = np.random.rand(10, 3)
+    projected_points = camera.project(points)
+    assert projected_points.shape == (points.shape[0], 1, 2)
+
+    points = np.random.rand(10, 1, 3)
+    projected_points = camera.project(points)
+    assert projected_points.shape == (points.shape[0], 1, 2)
+
+
+if __name__ == "__main__":
+    pytest.main([__file__])

From 553964e5efe064fd0665fc3e5868befee83273c8 Mon Sep 17 00:00:00 2001
From: roomrys <38435167+roomrys@users.noreply.github.com>
Date: Wed, 20 Nov 2024 12:57:03 -0800
Subject: [PATCH 5/8] Conform to pydocstyle

---
 sleap_io/model/camera.py   | 10 ----------
 tests/model/test_camera.py | 11 -----------
 2 files changed, 21 deletions(-)

diff --git a/sleap_io/model/camera.py b/sleap_io/model/camera.py
index 8c902238..30a20acb 100644
--- a/sleap_io/model/camera.py
+++ b/sleap_io/model/camera.py
@@ -59,7 +59,6 @@ def _validate_shape(self, attribute: attrs.Attribute, value):
         Raises:
             ValueError: If attribute shape is not as expected.
         """
-
         # Define metadata for each attribute
         attr_metadata = {
             "matrix": {"shape": (3, 3), "type": np.ndarray},
@@ -87,7 +86,6 @@ def _validate_shape(self, attribute: attrs.Attribute, value):
 
     def __attrs_post_init__(self):
         """Initialize extrinsic matrix from rotation and translation vectors."""
-
         # Initialize extrinsic matrix
         self._extrinsic_matrix = np.eye(4, dtype="float64")
         self._extrinsic_matrix[:3, :3] = cv2.Rodrigues(self._rvec)[0]
@@ -100,7 +98,6 @@ def rvec(self) -> np.ndarray:
         Returns:
             Rotation vector of camera of size 3.
         """
-
         return self._rvec
 
     @rvec.setter
@@ -123,7 +120,6 @@ def tvec(self) -> np.ndarray:
         Returns:
             Translation vector of camera of size 3.
         """
-
         return self._tvec
 
     @tvec.setter
@@ -133,7 +129,6 @@ def tvec(self, value: np.ndarray):
         Args:
             value: Translation vector of size 3.
         """
-
         self._tvec = value
 
         # Update extrinsic matrix
@@ -146,7 +141,6 @@ def extrinsic_matrix(self) -> np.ndarray:
         Returns:
             Extrinsic matrix of camera of size 4 x 4.
         """
-
         return self._extrinsic_matrix
 
     @extrinsic_matrix.setter
@@ -156,7 +150,6 @@ def extrinsic_matrix(self, value: np.ndarray):
         Args:
             value: Extrinsic matrix of size 4 x 4.
         """
-
         self._extrinsic_matrix = value
 
         # Update rotation and translation vectors
@@ -172,7 +165,6 @@ def undistort_points(self, points: np.ndarray) -> np.ndarray:
         Returns:
             Undistorted points of shape (N, 2).
         """
-
         shape = points.shape
         points = points.reshape(-1, 1, 2)
         out = cv2.undistortPoints(points, self.matrix, self.dist)
@@ -187,7 +179,6 @@ def project(self, points: np.ndarray) -> np.ndarray:
         Returns:
             Projected 2D points of shape (N, 1, 2).
         """
-
         points = points.reshape(-1, 1, 3)
         out, _ = cv2.projectPoints(
             points,
@@ -211,7 +202,6 @@ def __getattr__(self, name: str):
         Raises:
             AttributeError: If attribute does not exist.
         """
-
         if name in self.__attrs_attrs__:
             return getattr(self, name)
 
diff --git a/tests/model/test_camera.py b/tests/model/test_camera.py
index db70779d..383f92e6 100644
--- a/tests/model/test_camera.py
+++ b/tests/model/test_camera.py
@@ -9,7 +9,6 @@
 
 def test_camera_name():
     """Test camera name converter always converts to string."""
-
     # During initialization
     camera = Camera(name=12)
     assert camera.name == "12"
@@ -25,7 +24,6 @@ def test_camera_name():
 
 def test_camera_matrix():
     """Test camera matrix converter and validator."""
-
     matrix_list = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
     matrix_array = np.array(matrix_list)
 
@@ -48,7 +46,6 @@ def test_camera_matrix():
 
 def test_camera_distortions():
     """Test camera distortion converter and validator."""
-
     distortions_unraveled = [[1], [2], [3], [4], [5]]
     distortions_raveled = np.array(distortions_unraveled).ravel()
 
@@ -68,7 +65,6 @@ def test_camera_distortions():
 
 def test_camera_size():
     """Test camera size converter and validator."""
-
     size = (100, 200)
 
     # During initialization
@@ -96,7 +92,6 @@ def construct_extrinsic_matrix(rvec, tvec):
     Returns:
         Extrinsic matrix of camera of size (4, 4) and type float64.
     """
-
     extrinsic_matrix = np.eye(4)
     extrinsic_matrix[:3, :3] = cv2.Rodrigues(np.array(rvec))[0]
     extrinsic_matrix[:3, 3] = tvec
@@ -106,7 +101,6 @@ def construct_extrinsic_matrix(rvec, tvec):
 
 def test_camera_rvec():
     """Test camera rotation vector converter and validator."""
-
     rvec = [1, 2, 3]
 
     # During initialization
@@ -138,7 +132,6 @@ def test_camera_rvec():
 
 def test_camera_tvec():
     """Test camera translation vector converter and validator."""
-
     tvec = [1, 2, 3]
 
     # During initialization
@@ -167,7 +160,6 @@ def test_camera_tvec():
 
 def test_camera_extrinsic_matrix():
     """Test camera extrinsic matrix method."""
-
     # During initialization
 
     # ... with rvec and tvec
@@ -207,7 +199,6 @@ def test_camera_extrinsic_matrix():
 # TODO: Remove when implement triangulation without aniposelib
 def test_camera_aliases():
     """Test camera aliases for attributes."""
-
     camera = Camera(
         matrix=[[1, 2, 3], [4, 5, 6], [7, 8, 9]],
         dist=[[1], [2], [3], [4], [5]],
@@ -226,7 +217,6 @@ def test_camera_aliases():
 
 def test_camera_undistort_points():
     """Test camera undistort points method."""
-
     camera = Camera(
         matrix=[[1, 0, 0], [0, 1, 0], [0, 0, 1]],
         dist=[[0], [0], [0], [0], [0]],
@@ -246,7 +236,6 @@ def test_camera_undistort_points():
 
 def test_camera_project():
     """Test camera project method."""
-
     camera = Camera(
         matrix=[[1, 0, 0], [0, 1, 0], [0, 0, 1]],
         dist=[[0], [0], [0], [0], [0]],

From 32367ab2ba4474983f6c82f6525e6c8d3f906871 Mon Sep 17 00:00:00 2001
From: roomrys <38435167+roomrys@users.noreply.github.com>
Date: Fri, 22 Nov 2024 08:40:40 -0800
Subject: [PATCH 6/8] Add method to link Camera to Video

---
 sleap_io/model/camera.py | 92 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 92 insertions(+)

diff --git a/sleap_io/model/camera.py b/sleap_io/model/camera.py
index 30a20acb..896bc4e5 100644
--- a/sleap_io/model/camera.py
+++ b/sleap_io/model/camera.py
@@ -7,8 +7,88 @@
 import numpy as np
 from attrs import define, field
 
+from sleap_io.model.video import Video
+
 
 @define
+class CameraGroup:
+    """A group of cameras used to record a multi-view `RecordingSession`.
+
+    Attributes:
+        cameras: List of `Camera` objects in the group.
+    """
+
+    cameras: list[Camera] = field(factory=list)
+
+
+@define(eq=False)  # Set eq to false to make class hashable
+class RecordingSession:
+    """A recording session with multiple cameras.
+
+    Attributes:
+        camera_group: `CameraGroup` object containing cameras in the session.
+        _video_by_camera: Dictionary mapping `Camera` to `Video`.
+        _camera_by_video: Dictionary mapping `Video` to `Camera`.
+    """
+
+    camera_group: CameraGroup = field(factory=CameraGroup)
+    _video_by_camera: dict[Camera, Video] = field(factory=dict)
+    _camera_by_video: dict[Video, Camera] = field(factory=dict)
+
+    def get_video(self, camera: Camera) -> Video | None:
+        """Get `Video` associated with `Camera`.
+
+        Args:
+            camera: Camera to get video
+
+        Returns:
+            Video associated with camera or None if not found
+        """
+        return self._video_by_camera.get(camera, None)
+
+    def add_video(self, video: Video, camera: Camera):
+        """Add `Video` to `RecordingSession` and mapping to `Camera`.
+
+        Args:
+            video: `Video` object to add to `RecordingSession`.
+            camera: `Camera` object to associate with `Video`.
+
+        Raises:
+            ValueError: If `Camera` is not in associated `CameraGroup`.
+            ValueError: If `Video` is not a `Video` object.
+        """
+        # Raise ValueError if camera is not in associated camera group
+        self.camera_group.cameras.index(camera)
+
+        # Raise ValueError if `Video` is not a `Video` object
+        if not isinstance(video, Video):
+            raise ValueError(
+                f"Expected `Video` object, but received {type(video)} object."
+            )
+
+        # Add camera to video mapping
+        self._video_by_camera[camera] = video
+
+        # Add video to camera mapping
+        self._camera_by_video[video] = camera
+
+    def remove_video(self, video: Video):
+        """Remove `Video` from `RecordingSession` and mapping to `Camera`.
+
+        Args:
+            video: `Video` object to remove from `RecordingSession`.
+
+        Raises:
+            ValueError: If `Video` is not in associated `RecordingSession`.
+        """
+        # Remove video from camera mapping
+        camera = self._camera_by_video.pop(video)
+
+        # Remove camera from video mapping
+        self._video_by_camera.pop(camera)
+
+
+@define(eq=False)  # Set eq to false to make class hashable
 class Camera:
     """A camera used to record in a multi-view `RecordingSession`.
 
@@ -22,6 +102,7 @@ class Camera:
         tvec: Translation vector of size (3,) and type float64.
         extrinsic_matrix: Extrinsic matrix of camera of size (4, 4) and type float64.
         name: Camera name.
+        _video_by_session: Dictionary mapping `RecordingSession` to `Video`.
     """
 
     matrix: np.ndarray = field(
@@ -189,6 +270,17 @@ def project(self, points: np.ndarray) -> np.ndarray:
         )
         return out
 
+    def get_video(self, session: RecordingSession) -> Video | None:
+        """Get video associated with recording session.
+
+        Args:
+            session: Recording session to get video for.
+
+        Returns:
+            Video associated with recording session or None if not found.
+        """
+        return session.get_video(camera=self)
+
     # TODO: Remove this when we implement triangulation without aniposelib
     def __getattr__(self, name: str):
         """Get attribute by name.

From 6240f0da16e94328ea9eb421f7714595ea2e9c9e Mon Sep 17 00:00:00 2001
From: roomrys <38435167+roomrys@users.noreply.github.com>
Date: Fri, 22 Nov 2024 08:41:12 -0800
Subject: [PATCH 7/8] Test Camera to Video link

---
 tests/model/test_camera.py | 61 ++++++++++++++++++++++++--------------
 1 file changed, 39 insertions(+), 22 deletions(-)

diff --git a/tests/model/test_camera.py b/tests/model/test_camera.py
index 383f92e6..243e672d 100644
--- a/tests/model/test_camera.py
+++ b/tests/model/test_camera.py
@@ -4,7 +4,8 @@
 import numpy as np
 import pytest
 
-from sleap_io.model.camera import Camera
+from sleap_io.model.camera import Camera, CameraGroup, RecordingSession
+from sleap_io.model.video import Video
 
 
 def test_camera_name():
@@ -196,25 +197,6 @@ def test_camera_extrinsic_matrix():
     np.testing.assert_array_equal(camera.tvec, tvec)
 
 
-# TODO: Remove when implement triangulation without aniposelib
-def test_camera_aliases():
-    """Test camera aliases for attributes."""
-    camera = Camera(
-        matrix=[[1, 2, 3], [4, 5, 6], [7, 8, 9]],
-        dist=[[1], [2], [3], [4], [5]],
-        size=(100, 200),
-        rvec=[1, 2, 3],
-        tvec=[1, 2, 3],
-        name="camera",
-    )
-
-    # Test __getattr__ aliases
-    assert camera.get_name() == camera.name
-    np.testing.assert_array_equal(
-        camera.get_extrinsic_matrix(), camera.extrinsic_matrix
-    )
-
-
 def test_camera_undistort_points():
     """Test camera undistort points method."""
     camera = Camera(
@@ -250,5 +232,40 @@ def test_camera_project():
     assert projected_points.shape == (points.shape[0], 1, 2)
 
 
-if __name__ == "__main__":
-    pytest.main([__file__])
+def test_camera_get_video():
+    """Test camera get video method."""
+    camera = Camera()
+    camera_group = CameraGroup(cameras=[camera])
+
+    # Test with no video
+    session = RecordingSession(camera_group=camera_group)
+    video = camera.get_video(session)
+    assert video is None
+
+    # Test with video
+    video = Video(filename="not/a/file.mp4")
+    session.add_video(video=video, camera=camera)
+    assert camera.get_video(session) is video
+
+    # Remove video
+    session.remove_video(video)
+    assert camera.get_video(session) is None
+
+
+# TODO: Remove when implement triangulation without aniposelib
+def test_camera_aliases():
+    """Test camera aliases for attributes."""
+    camera = Camera(
+        matrix=[[1, 2, 3], [4, 5, 6], [7, 8, 9]],
+        dist=[[1], [2], [3], [4], [5]],
+        size=(100, 200),
+        rvec=[1, 2, 3],
+        tvec=[1, 2, 3],
+        name="camera",
+    )
+
+    # Test __getattr__ aliases
+    assert camera.get_name() == camera.name
+    np.testing.assert_array_equal(
+        camera.get_extrinsic_matrix(), camera.extrinsic_matrix
+    )

From 250a8c545aca6ddfba37a4d672c810f7c3e37341 Mon Sep 17 00:00:00 2001
From: roomrys <38435167+roomrys@users.noreply.github.com>
Date: Wed, 27 Nov 2024 09:34:48 -0800
Subject: [PATCH 8/8] Convert points to float before cv2.undistortPoints

---
 sleap_io/model/camera.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sleap_io/model/camera.py b/sleap_io/model/camera.py
index 896bc4e5..530939f3 100644
--- a/sleap_io/model/camera.py
+++ b/sleap_io/model/camera.py
@@ -248,7 +248,7 @@ def undistort_points(self, points: np.ndarray) -> np.ndarray:
         """
         shape = points.shape
         points = points.reshape(-1, 1, 2)
-        out = cv2.undistortPoints(points, self.matrix, self.dist)
+        out = cv2.undistortPoints(points.astype("float64"), self.matrix, self.dist)
         return out.reshape(shape)
 
     def project(self, points: np.ndarray) -> np.ndarray: