# -*- coding: utf-8 -*-
##########################################################################
# pySAP - Copyright (C) CEA, 2017 - 2018
# Distributed under the terms of the CeCILL-B license, as published by
# the CEA-CNRS-INRIA. Refer to the LICENSE file or to
# http://www.cecill.info/licences/Licence_CeCILL-B_V1-en.html
# for details.
##########################################################################
"""WAVELET.
This module defines functions for wavelet decomposition.
"""
import numpy as np
from pysap import load_transform
[docs]def decompose(data, n_scales=4):
"""Decompose.
Obtain the wavelet decomposition of the input data using an isotropic
undecimated wavelet transform.
Parameters
----------
data : numpy.ndarray
Input 2D-array
n_scales : int, optional
Number of wavelet scales, default is ``4``
Returns
-------
numpy.ndarray
Wavelet decomposition 3D-array
Raises
------
TypeError
For invalid input ``data`` type
TypeError
For invalid input ``n_scales`` type
Examples
--------
>>> import numpy as np
>>> from astro.denoising.wavelet import decompose
>>> data = np.arange(9).reshape((3, 3)) * 0.1
>>> decompose(data)
array([[[-1.50000006e-01, -1.12500034e-01, -7.50000030e-02],
[-3.75000238e-02, -2.98023224e-08, 3.74999642e-02],
[ 7.49999881e-02, 1.12499952e-01, 1.49999976e-01]],
[[-1.56250030e-01, -1.17187500e-01, -7.81250298e-02],
[-3.90625000e-02, 0.00000000e+00, 3.90625000e-02],
[ 7.81250000e-02, 1.17187500e-01, 1.56250000e-01]],
[[-5.85937500e-02, -4.39453125e-02, -2.92968750e-02],
[-1.46484375e-02, 0.00000000e+00, 1.46484375e-02],
[ 2.92968750e-02, 4.39453125e-02, 5.85937500e-02]],
[[ 3.64843786e-01, 3.73632848e-01, 3.82421911e-01],
[ 3.91210973e-01, 4.00000036e-01, 4.08789098e-01],
[ 4.17578161e-01, 4.26367223e-01, 4.35156286e-01]]])
"""
if not isinstance(data, np.ndarray) or data.ndim != 2:
raise TypeError('Input data must be a 2D numpy array.')
if not isinstance(n_scales, int) or n_scales < 1:
raise TypeError('n_scales must be a positive integer.')
trans_name = 'BsplineWaveletTransformATrousAlgorithm'
trans = load_transform(trans_name)(
nb_scale=n_scales,
padding_mode="symmetric",
)
trans.data = data
trans.analysis()
res = np.array(trans.analysis_data, dtype=np.float64)
return res
[docs]def recombine(data):
"""Recombine.
Recombine a wavelet decomposition.
Parameters
----------
data : numpy.ndarray
Input 3D-array
Returns
-------
numpy.ndarray
Recombined 2D-array
Raises
------
TypeError
For invalid input ``data`` type
Examples
--------
>>> import numpy as np
>>> from pysap.astro.denoising.wavelet import recombine
>>> np.random.seed(0)
>>> data = np.random.ranf((4, 3, 3))
>>> recombine(data)
array([[2.65508069, 2.89877487, 2.52493858],
[2.17664192, 2.58496449, 1.95360968],
[1.21142489, 1.57070222, 2.55727139]])
"""
if not isinstance(data, np.ndarray) or data.ndim != 3:
raise TypeError('Input data must be a 3D numpy array.')
return np.sum(data, axis=0)
