Function angle_distance_between_rigid

mne/transforms.py:1374–1409

Compute the angle and distance between two rigid transforms. Parameters ---------- a : array, shape (..., 4, 4) First rigid transform. b : array, shape (..., 4, 4) | None Second rigid transform. If None, the identity transform is used. angle_units : str U

(a, b=None, *, angle_units="rad", distance_units="m")

def angle_distance_between_rigid(a, b=None, *, angle_units="rad", distance_units="m"):
    """Compute the angle and distance between two rigid transforms.

    Parameters
    ----------
    a : array, shape (..., 4, 4)
        First rigid transform.
    b : array, shape (..., 4, 4) | None
        Second rigid transform. If None, the identity transform is used.
    angle_units : str
        Units for the angle output, either "rad" or "deg".
    distance_units : str
        Units for the distance output, either "m" or "mm".

    Returns
    -------
    angles : array, shape (...)
        The angles between the two transforms.
    distances : array, shape (...)
        The distances between the two transforms.

    Notes
    -----
    .. versionadded:: 1.11
    """
    a = _affine_to_quat(a, name="a")
    b = np.zeros(6) if b is None else _affine_to_quat(b, name="b")
    ang = _angle_between_quats(a[..., :3], b[..., :3])
    dist = np.linalg.norm(a[..., 3:] - b[..., 3:], axis=-1)
    assert isinstance(angle_units, str) and angle_units in ("rad", "deg")
    if angle_units == "deg":
        ang = np.rad2deg(ang)
    assert isinstance(distance_units, str) and distance_units in ("m", "mm")
    if distance_units == "mm":
        dist *= 1e3
    return ang, dist


def _angle_between_quats(x, y=None):