magni.imaging.dictionaries.utils module

Module providing support functionality for the dictionaries subpackage.

Routine listings

get_function_handle(type_, transform)

Function to get a function handle to a transform method.

get_transform_names()

Function to get a tuple of names of the available transforms.

magni.imaging.dictionaries.utils.get_function_handle(type_, transform)

Return a function handle to a given transform method.

Parameters:

• type_ ({‘matrix’, ‘transform_matrix’, ‘visualisation’}) – Identifier of the type of method to return a handle to.
• transform (str) – Identifier of the transform method to return a handle to.

Returns:

f_handle (function) – Handle to transform.

Notes

The available types are:

• matrix : 2D transform matrix object.
• transform_matrix : 1D transform matrix.
• visualisation : Coefficient visualisation preparation function.

Examples

For example, return a handle to the matrix method for a DCT:

>>> from magni.imaging.dictionaries.utils import get_function_handle
>>> get_function_handle('matrix', 'DCT').__name__
'get_DCT'

or return a handle to the 1D DCT transform matrix method:

>>> get_function_handle('transform_matrix', 'DCT').__name__
'get_DCT_transform_matrix'

or return a handle to the visualisation method for a DFT:

>>> get_function_handle('visualisation', 'DFT').__name__
'visualise_DFT'

magni.imaging.dictionaries.utils.get_transform_names()

Return a tuple of names of the available transforms.

Returns:names (tuple) – The tuple of names of available transforms.

Examples

For example, get transform names and extract ‘DCT’ and ‘DFT’

>>> from magni.imaging.dictionaries.utils import get_transform_names
>>> names = get_transform_names()
>>> tuple(sorted(name for name in names if name in ('DCT', 'DFT')))
('DCT', 'DFT')

and a handle to corresponding visualisation method for the DCT

>>> from magni.imaging.dictionaries.utils import get_function_handle
>>> f_handles = tuple(get_function_handle('visualisation', name)
... for name in names)
>>> tuple(f_h.__name__ for f_h in f_handles if 'DCT' in f_h.__name__)
('visualise_DCT',)