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Camera

Mono/stereo camera models.

Camera(intrinsics=CameraIntrinsics(), distortion=DistortionCoefficients(), extrinsics=Pose3D()) dataclass

Bases: CameraBase

Standard pinhole camera.

Attributes:

Name Type Description
intrinsics CameraIntrinsics

Intrinsic parameters.
distortion DistortionCoefficients

Distortion coefficients.
extrinsics Pose3D

Extrinsic parameters.

project(points, points_frame=None)

Project 3D points into the image plane.

Parameters:

Name Type Description Default
points ndarray

3D points as a 3xN numpy array.

 required
points_frame Optional[Pose3D]

Pose of the points frame relative to the camera frame. If None, the points are assumed to be in the camera frame.

 None

Returns:

Type Description
ndarray

Projected points as a 2xN numpy array.
Source code in src/compas_camcal/models/camera.py 
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def project(self, points: np.ndarray, points_frame: Optional[Pose3D] = None) -> np.ndarray:
    """
    Project 3D points into the image plane.

    Args:
        points: 3D points as a 3xN numpy array.
        points_frame: Pose of the points frame relative to the camera frame. If None, the points are assumed to be in the camera frame.

    Returns:
        Projected points as a 2xN numpy array.
    """
    if points_frame is not None:
        # Convert rotation/translation
        rodrigues_rotation, _ = cv2.Rodrigues(points_frame.rotation.to_matrix())
        translation = points_frame.translation.to_vector()
    else:
        rodrigues_rotation = np.zeros((3, 1))
        translation = np.zeros((3, 1))

    # Project points into image plane
    image_points, _ = cv2.projectPoints(
        points,
        rodrigues_rotation,
        translation,
        self.intrinsics.to_matrix(),
        self.distortion.to_vector().ravel(),
    )

    image_points = image_points.reshape(-1, 2)

    return image_points

undistort(image)

Undistort an image.

Parameters:

Name Type Description Default
image ndarray

Image to undistort.

 required

Returns:

Type Description
ndarray

Undistorted image.
Source code in src/compas_camcal/models/camera.py 
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def undistort(self, image: np.ndarray) -> np.ndarray:
    """
    Undistort an image.

    Args:
        image: Image to undistort.

    Returns:
        Undistorted image.
    """
    return cv2.undistort(
        image, self.intrinsics.to_matrix(), self.distortion.to_vector().ravel()
    )

CameraBase(intrinsics=CameraIntrinsics(), distortion=DistortionCoefficientsBase(), extrinsics=Pose3D()) dataclass

Bases: ABC

Abstract base class for cameras.

Attributes:

Name Type Description
intrinsics CameraIntrinsics

Intrinsic parameters.
distortion DistortionCoefficientsBase

Distortion coefficients.
extrinsics Pose3D

Extrinsic parameters.

project(points, points_frame=None) abstractmethod

Project 3D points into the image plane.

Parameters:

Name Type Description Default
points ndarray

3D points as a 3xN numpy array.

 required
points_frame Optional[Pose3D]

Pose of the points frame relative to the camera frame. If None, the points are assumed to be in the camera frame.

 None

Returns:

Type Description
ndarray

Projected points as a 2xN numpy array.
Source code in src/compas_camcal/models/camera.py 
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@abstractmethod
def project(self, points: np.ndarray, points_frame: Optional[Pose3D] = None) -> np.ndarray:
    """
    Project 3D points into the image plane.

    Args:
        points: 3D points as a 3xN numpy array.
        points_frame: Pose of the points frame relative to the camera frame. If None, the points are assumed to be in the camera frame.

    Returns:
        Projected points as a 2xN numpy array.
    """
    raise NotImplementedError

undistort(image) abstractmethod

Undistort an image.

Parameters:

Name Type Description Default
image ndarray

Image to undistort.

 required

Returns:

Type Description
ndarray

Undistorted image.
Source code in src/compas_camcal/models/camera.py 
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@abstractmethod
def undistort(self, image: np.ndarray) -> np.ndarray:
    """
    Undistort an image.

    Args:
        image: Image to undistort.

    Returns:
        Undistorted image.
    """
    raise NotImplementedError

FisheyeCamera(intrinsics=CameraIntrinsics(), distortion=FisheyeDistortionCoefficients(), extrinsics=Pose3D()) dataclass

Bases: CameraBase

Fisheye camera.

Attributes:

Name Type Description
intrinsics CameraIntrinsics

Intrinsic parameters.
distortion FisheyeDistortionCoefficients

Distortion coefficients.
extrinsics Pose3D

Extrinsic parameters.

project(points, points_frame=None)

Project 3D points into the image plane.

Parameters:

Name Type Description Default
points ndarray

3D points as a 3xN numpy array.

 required
points_frame Optional[Pose3D]

Pose of the points frame relative to the camera frame. If None, the points are assumed to be in the camera frame.

 None

Returns:

Type Description
ndarray

Projected points as a 2xN numpy array.
Source code in src/compas_camcal/models/camera.py 
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def project(self, points: np.ndarray, points_frame: Optional[Pose3D] = None) -> np.ndarray:
    """
    Project 3D points into the image plane.

    Args:
        points: 3D points as a 3xN numpy array.
        points_frame: Pose of the points frame relative to the camera frame. If None, the points are assumed to be in the camera frame.

    Returns:
        Projected points as a 2xN numpy array.
    """
    if points_frame is not None:
        # Convert rotation/translation
        rodrigues_rotation, _ = cv2.Rodrigues(points_frame.rotation.to_matrix())
        translation = points_frame.translation.to_vector()
    else:
        rodrigues_rotation = np.zeros((3, 1))
        translation = np.zeros((3, 1))

    # Project points into image plane
    image_points, _ = cv2.fisheye.projectPoints(
        points,
        rodrigues_rotation,
        translation,
        self.intrinsics.to_matrix(),
        self.distortion.to_vector().ravel(),
    )

    image_points = image_points.reshape(-1, 2)

    return image_points

undistort(image)

Undistort an image.

Parameters:

Name Type Description Default
image ndarray

Image to undistort.

 required

Returns:

Type Description
ndarray

Undistorted image.
Source code in src/compas_camcal/models/camera.py 
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def undistort(self, image: np.ndarray) -> np.ndarray:
    """
    Undistort an image.

    Args:
        image: Image to undistort.

    Returns:
        Undistorted image.
    """
    return cv2.fisheye.undistortImage(
        image, self.intrinsics.to_matrix(), self.distortion.to_vector().ravel()
    )

StereoCamera(camera_1, camera_2) dataclass

Stereo camera pair.

Attributes:

Name Type Description
camera_1 CameraBase

First camera. By convention, the left camera.
camera_2 CameraBase

Second camera. By convention, the right camera.

relative_pose property

Calculate the relative pose between the two cameras. This is the pose of camera_2 in camera_1's frame.

Returns:

Type Description
Pose3D

Relative pose between the two cameras.

project(points, points_frame=None)

Project a set of 3D points into both image planes.

Parameters:

Name Type Description Default
points ndarray

3D points as a 3xN numpy array.

 required
points_frame Optional[Pose3D]

Pose of the points frame relative to the camera_1 frame. If None, the points are assumed to be in the camera frame.

 None

Returns:

Type Description
ndarray

Projected points for camera_1 as a 2xN numpy array.
ndarray

Projected points for camera_2 as a 2xN numpy array.
Source code in src/compas_camcal/models/camera.py 
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def project(
    self, points: np.ndarray, points_frame: Optional[Pose3D] = None
) -> Tuple[np.ndarray, np.ndarray]:
    """
    Project a set of 3D points into both image planes.

    Args:
        points: 3D points as a 3xN numpy array.
        points_frame: Pose of the points frame relative to the camera_1 frame. If None, the points are assumed to be in the camera frame.

    Returns:
        Projected points for camera_1 as a 2xN numpy array.
        Projected points for camera_2 as a 2xN numpy array.
    """
    # Project points into each image plane
    image_points_1 = self.camera_1.project(points, points_frame=points_frame)
    image_points_2 = self.camera_2.project(
        points, points_frame=self.relative_pose @ points_frame
    )

    return image_points_1, image_points_2