def derenzo_sources(space):
"""Create the PET/SPECT Derenzo sources phantom.
The Derenzo phantom contains a series of circles of decreasing size.
In 3d the phantom is simply the 2d phantom extended in the z direction as
cylinders.
"""
if space.ndim == 2:
return ellipse_phantom(space, _derenzo_sources_2d())
if space.ndim == 3:
return ellipse_phantom(
space, cylinders_from_ellipses(_derenzo_sources_2d()))
else:
raise ValueError('dimension not 2, no phantom available')
def shepp_logan(space, modified=False):
"""Standard `Shepp-Logan phantom`_ in 2 or 3 dimensions.
Parameters
----------
space : `DiscreteLp`
Space in which the phantom is created, must be 2- or 3-dimensional.
If ``space.shape`` is 1 in an axis, a corresponding slice of the
phantom is created.
modified : `bool`, optional
True if the modified Shepp-Logan phantom should be given.
The modified phantom has greatly amplified contrast to aid
visualization.
See Also
--------
forbild : Similar phantom but with more complexity. Only supports 2d.
odl.phantom.geometric.defrise : Geometry test phantom
shepp_logan_ellipses : Get the parameters that define this phantom
odl.phantom.geometric.ellipse_phantom :
Function for creating arbitrary ellipse phantoms
References
----------
.. _Shepp-Logan phantom: en.wikipedia.org/wiki/Shepp–Logan_phantom
"""
ellipses = shepp_logan_ellipses(space.ndim, modified)
return ellipse_phantom(space, ellipses)
