Source code for colour.colorimetry.correction

# -*- coding: utf-8 -*-
"""
Spectral Bandpass Dependence Correction
=======================================

Defines objects to perform spectral bandpass dependence correction.

The following correction methods are available:

-   :func:`colour.colorimetry.bandpass_correction_Stearns1988`:
    *Stearns and Stearns (1988)* spectral bandpass dependence correction
    method.
-   :attr:`colour.BANDPASS_CORRECTION_METHODS`: Supported spectral bandpass
    dependence correction methods.
-   :func:`colour.bandpass_correction`: Spectral bandpass dependence
    correction using given method.

References
----------
-   :cite:`Stearns1988a` : Stearns, E. I., & Stearns, R. E. (1988). An example
    of a method for correcting radiance data for Bandpass error. Color Research
    & Application, 13(4), 257-259. doi:10.1002/col.5080130410
-   :cite:`Westland2012f` : Westland, S., Ripamonti, C., & Cheung, V. (2012).
    Correction for Spectral Bandpass. In Computational Colour Science Using
    MATLAB (2nd ed., p. 38). ISBN:978-0-470-66569-5
"""

from __future__ import division, unicode_literals

import numpy as np

from colour.utilities import CaseInsensitiveMapping

__author__ = 'Colour Developers'
__copyright__ = 'Copyright (C) 2013-2020 - Colour Developers'
__license__ = 'New BSD License - https://opensource.org/licenses/BSD-3-Clause'
__maintainer__ = 'Colour Developers'
__email__ = 'colour-developers@colour-science.org'
__status__ = 'Production'

__all__ = [
    'bandpass_correction_Stearns1988', 'BANDPASS_CORRECTION_METHODS',
    'bandpass_correction'
]

ALPHA_STEARNS = 0.083


[docs]def bandpass_correction_Stearns1988(sd): """ Implements spectral bandpass dependence correction on given spectral distribution using *Stearns and Stearns (1988)* method. Parameters ---------- sd : SpectralDistribution Spectral distribution. Returns ------- SpectralDistribution Spectral bandpass dependence corrected spectral distribution. References ---------- :cite:`Stearns1988a`, :cite:`Westland2012f` Examples -------- >>> from colour import SpectralDistribution >>> from colour.utilities import numpy_print_options >>> data = { ... 500: 0.0651, ... 520: 0.0705, ... 540: 0.0772, ... 560: 0.0870, ... 580: 0.1128, ... 600: 0.1360 ... } >>> with numpy_print_options(suppress=True): ... bandpass_correction_Stearns1988(SpectralDistribution(data)) ... # doctest: +ELLIPSIS SpectralDistribution([[ 500. , 0.0646518...], [ 520. , 0.0704293...], [ 540. , 0.0769485...], [ 560. , 0.0856928...], [ 580. , 0.1129644...], [ 600. , 0.1379256...]], interpolator=SpragueInterpolator, interpolator_kwargs={}, extrapolator=Extrapolator, extrapolator_kwargs={...}) """ values = np.copy(sd.values) values[0] = (1 + ALPHA_STEARNS) * values[0] - ALPHA_STEARNS * values[1] values[-1] = (1 + ALPHA_STEARNS) * values[-1] - ALPHA_STEARNS * values[-2] for i in range(1, len(values) - 1): values[i] = (-ALPHA_STEARNS * values[i - 1] + (1 + 2 * ALPHA_STEARNS) * values[i] - ALPHA_STEARNS * values[i + 1]) sd.values = values return sd
BANDPASS_CORRECTION_METHODS = CaseInsensitiveMapping({ 'Stearns 1988': bandpass_correction_Stearns1988 }) BANDPASS_CORRECTION_METHODS.__doc__ = """ Supported spectral bandpass dependence correction methods. BANDPASS_CORRECTION_METHODS : CaseInsensitiveMapping **{'Stearns 1988', }** """
[docs]def bandpass_correction(sd, method='Stearns 1988'): """ Implements spectral bandpass dependence correction on given spectral distribution using given method. Parameters ---------- sd : SpectralDistribution Spectral distribution. method : unicode, optional {'Stearns 1988', } Correction method. Returns ------- SpectralDistribution Spectral bandpass dependence corrected spectral distribution. References ---------- :cite:`Stearns1988a`, :cite:`Westland2012f` Examples -------- >>> from colour import SpectralDistribution >>> from colour.utilities import numpy_print_options >>> data = { ... 500: 0.0651, ... 520: 0.0705, ... 540: 0.0772, ... 560: 0.0870, ... 580: 0.1128, ... 600: 0.1360 ... } >>> with numpy_print_options(suppress=True): ... bandpass_correction(SpectralDistribution(data)) ... # doctest: +ELLIPSIS SpectralDistribution([[ 500. , 0.0646518...], [ 520. , 0.0704293...], [ 540. , 0.0769485...], [ 560. , 0.0856928...], [ 580. , 0.1129644...], [ 600. , 0.1379256...]], interpolator=SpragueInterpolator, interpolator_kwargs={}, extrapolator=Extrapolator, extrapolator_kwargs={...}) """ return BANDPASS_CORRECTION_METHODS.get(method)(sd)