symforce.cam.polynomial_camera_cal module

class PolynomialCameraCal(focal_length, principal_point, distortion_coeffs=(0.0, 0.0, 0.0), critical_undistorted_radius=None, max_fov=2.0943951023931953)[source]

Bases: CameraCal

Polynomial camera model in the style of OpenCV

Distortion is a multiplicative factor applied to the image plane coordinates in the camera frame. Mapping between distorted image plane coordinates and image coordinates is done using a standard linear model.

The distortion function is a 6th order even polynomial that is a function of the radius of the image plane coordinates:

r = (p_img[0] ** 2 + p_img[1] ** 2) ** 0.5
distorted_weight = 1 + c0 * r^2 + c1 * r^4 + c2 * r^6
uv = p_img * distorted_weight
Parameters:

  • focal_length (T.Sequence[T.Scalar]) –

  • principal_point (T.Sequence[T.Scalar]) –

  • distortion_coeffs (T.Sequence[T.Scalar]) –

  • critical_undistorted_radius (T.Optional[T.Scalar]) –

  • max_fov (T.Scalar) –

NUM_DISTORTION_COEFFS = 3
DEFAULT_MAX_FOV = 2.0943951023931953
classmethod from_distortion_coeffs(focal_length, principal_point, distortion_coeffs=(), **kwargs)[source]

Construct a Camera Cal of type cls from the focal_length, principal_point, and distortion_coeffs.

kwargs are additional arguments which will be passed to the constructor.

Symbolic arguments may only be passed if the kwarg critical_undistorted_radius is passed.

Parameters:
Return type:

PolynomialCameraCal

classmethod storage_order()[source]

Return list of the names of values returned in the storage paired with the dimension of each value.

Return type:

Tuple[Tuple[str, int], …]

pixel_from_camera_point(point, epsilon=0.0)[source]

Project a 3D point in the camera frame into 2D pixel coordinates.

Returns:

  • pixel – (x, y) coordinate in pixels if valid

  • is_valid – 1 if the operation is within bounds else 0

Parameters:
Return type:

Tuple[Matrix21, float]

camera_ray_from_pixel(pixel, epsilon=0)[source]

Backproject a 2D pixel coordinate into a 3D ray in the camera frame.

Returns:

  • camera_ray – The ray in the camera frame (NOT normalized)

  • is_valid – 1 if the operation is within bounds else 0

Parameters:
Return type:

Tuple[Matrix31, float]

classmethod storage_dim()[source]

Dimension of underlying storage

Return type:

int

to_storage()[source]

Flat list representation of the underlying storage, length of storage_dim(). This is used purely for plumbing, it is NOT like a tangent space.

Return type:

List[float]

classmethod from_storage(vec)[source]

Construct from a flat list representation. Opposite of to_storage().

Parameters:

vec (Sequence[float]) –

Return type:

PolynomialCameraCal

classmethod symbolic(name, **kwargs)[source]

Construct a symbolic element with the given name prefix. Kwargs are forwarded to sf.Symbol (for example, sympy assumptions).

Parameters:

  • name (str) –

  • kwargs (Any) –

Return type:

PolynomialCameraCal