def elekta_xvi_fbp(ray_transform,
                   padding=False, filter_type='Hann', frequency_scaling=0.6):
    """Approximation of the FDK reconstruction used in the Elekta XVI.

    Parameters
    ----------
    ray_transform : `RayTransform`
        The ray transform to be used, should have an Elekta XVI geometry.
    padding : bool, optional
        Whether the FBP filter should use padding, increases memory use
        significantly.
    filter_type : str, optional
        Type of filter to apply in the FBP filter.
    frequency_scaling : float, optional
        Frequency scaling for FBP filter.

    Returns
    -------
    elekta_xvi_fbp : `DiscreteLp`

    Examples
    --------
    Create default FBP for default geometry:

    >>> from odl.contrib import tomo
    >>> geometry = tomo.elekta_xvi_geometry()
    >>> space = tomo.elekta_xvi_space()
    >>> ray_transform = odl.tomo.RayTransform(space, geometry)
    >>> fbp_op = tomo.elekta_xvi_fbp(ray_transform)
    """
    fbp_op = odl.tomo.fbp_op(ray_transform,
                             padding=padding,
                             filter_type=filter_type,
                             frequency_scaling=frequency_scaling)

    return fbp_op
Approximation of the FDK reconstruction used in the Elekta XVI.

    Parameters
    ----------
    ray_transform : `RayTransform`
        The ray transform to be used, should have an Elekta XVI geometry.
    padding : bool, optional
        Whether the FBP filter should use padding, increases memory use
        significantly.
    filter_type : str, optional
        Type of filter to apply in the FBP filter.
    frequency_scaling : float, optional
        Frequency scaling for FBP filter.

    Returns
    -------
    elekta_xvi_fbp : `DiscreteLp`

    Examples
    --------
    Create default FBP for default geometry:

    >>> from odl.contrib import tomo
    >>> geometry = tomo.elekta_xvi_geometry()
    >>> space = tomo.elekta_xvi_space()
    >>> ray_transform = odl.tomo.RayTransform(space, geometry)
    >>> fbp_op = tomo.elekta_xvi_fbp(ray_transform)