Source code for colour.colorimetry.correction

"""
Spectral Bandpass Dependence Correction
=======================================

Defines the 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 annotations

import numpy as np

from colour.colorimetry import SpectralDistribution
from colour.hints import Floating, Literal, Union
from colour.utilities import CaseInsensitiveMapping, validate_method

__author__ = "Colour Developers"
__copyright__ = "Copyright 2013 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",
]

CONSTANT_ALPHA_STEARNS: Floating = 0.083


[docs]def bandpass_correction_Stearns1988( sd: SpectralDistribution, ) -> SpectralDistribution: """ Implement spectral bandpass dependence correction on given spectral distribution using *Stearns and Stearns (1988)* method. Parameters ---------- sd Spectral distribution. Returns ------- :class:`colour.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 + CONSTANT_ALPHA_STEARNS) * values[ 0 ] - CONSTANT_ALPHA_STEARNS * values[1] values[-1] = (1 + CONSTANT_ALPHA_STEARNS) * values[ -1 ] - CONSTANT_ALPHA_STEARNS * values[-2] for i in range(1, len(values) - 1): values[i] = ( -CONSTANT_ALPHA_STEARNS * values[i - 1] + (1 + 2 * CONSTANT_ALPHA_STEARNS) * values[i] - CONSTANT_ALPHA_STEARNS * values[i + 1] ) sd.values = values return sd
BANDPASS_CORRECTION_METHODS: CaseInsensitiveMapping = CaseInsensitiveMapping( {"Stearns 1988": bandpass_correction_Stearns1988} ) BANDPASS_CORRECTION_METHODS.__doc__ = """ Supported spectral bandpass dependence correction methods. """
[docs]def bandpass_correction( sd: SpectralDistribution, method: Union[Literal["Stearns 1988"], str] = "Stearns 1988", ) -> SpectralDistribution: """ Implement spectral bandpass dependence correction on given spectral distribution using given method. Parameters ---------- sd Spectral distribution. method Correction method. Returns ------- :class:`colour.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={...}) """ method = validate_method(method, BANDPASS_CORRECTION_METHODS) return BANDPASS_CORRECTION_METHODS[method](sd)