Source code for colour.contrast

# -*- coding: utf-8 -*-
"""
References
----------
-   :cite:`Barten1999` : Barten, P. G. (1999). Contrast Sensitivity of the
    Human Eye and Its Effects on Image Quality. SPIE. doi:10.1117/3.353254
-   :cite:`Barten2003` : Barten, P. G. J. (2003). Formula for the contrast
    sensitivity of the human eye. In Y. Miyake & D. R. Rasmussen (Eds.),
    Proceedings of SPIE (Vol. 5294, pp. 231-238). doi:10.1117/12.537476
-   :cite:`Cowan2004` : Cowan, M., Kennel, G., Maier, T., & Walker, B. (2004).
    Contrast Sensitivity Experiment to Determine the Bit Depth for Digital
    Cinema. SMPTE Motion Imaging Journal, 113(9), 281-292. doi:10.5594/j11549
-   :cite:`InternationalTelecommunicationUnion2015` : International
    Telecommunication Union. (2015). Report ITU-R BT.2246-4 - The present
    state of ultra-high definition television BT Series Broadcasting service
    (Vol. 5, pp. 1-92).
    https://www.itu.int/dms_pub/itu-r/opb/rep/R-REP-BT.2246-4-2015-PDF-E.pdf
"""

from colour.utilities import (CaseInsensitiveMapping, filter_kwargs,
                              validate_method)

from .barten1999 import (optical_MTF_Barten1999, pupil_diameter_Barten1999,
                         sigma_Barten1999, retinal_illuminance_Barten1999,
                         maximum_angular_size_Barten1999,
                         contrast_sensitivity_function_Barten1999)

__all__ = [
    'optical_MTF_Barten1999', 'pupil_diameter_Barten1999', 'sigma_Barten1999',
    'retinal_illuminance_Barten1999', 'maximum_angular_size_Barten1999',
    'contrast_sensitivity_function_Barten1999'
]

CONTRAST_SENSITIVITY_METHODS = CaseInsensitiveMapping({
    'Barten 1999': contrast_sensitivity_function_Barten1999,
})
CONTRAST_SENSITIVITY_METHODS.__doc__ = """
Supported contrast sensitivity methods.

References
----------
:cite:`Barten1999`, :cite:`Barten2003`, :cite:`Cowan2004`,
:cite:`InternationalTelecommunicationUnion2015`,

CONTRAST_SENSITIVITY_METHODS : CaseInsensitiveMapping
    **{'Barten 1999'}**
"""


[docs]def contrast_sensitivity_function(method='Barten 1999', **kwargs): """ Returns the contrast sensitivity :math:`S` of the human eye according to the contrast sensitivity function (CSF) described by given method. Parameters ---------- method : unicode, optional **{'Barten 1999'}**, Computation method. Other Parameters ---------------- E : numeric or array_like, optional {:func:`colour.contrast.contrast_sensitivity_function_Barten1999`}, Retinal illuminance :math:`E` in Trolands. N_max : numeric or array_like, optional {:func:`colour.contrast.contrast_sensitivity_function_Barten1999`}, Maximum number of cycles :math:`N_{max}` over which the eye can integrate the information. T : numeric or array_like, optional {:func:`colour.contrast.contrast_sensitivity_function_Barten1999`}, Integration time :math:`T` in seconds of the eye. X_0 : numeric or array_like, optional {:func:`colour.contrast.contrast_sensitivity_function_Barten1999`}, Angular size :math:`X_0` in degrees of the object in the x direction. Y_0 : numeric or array_like, optional {:func:`colour.contrast.contrast_sensitivity_function_Barten1999`}, Angular size :math:`Y_0` in degrees of the object in the y direction. X_max : numeric or array_like, optional {:func:`colour.contrast.contrast_sensitivity_function_Barten1999`}, Maximum angular size :math:`X_{max}` in degrees of the integration area in the x direction. Y_max : numeric or array_like, optional {:func:`colour.contrast.contrast_sensitivity_function_Barten1999`}, Maximum angular size :math:`Y_{max}` in degrees of the integration area in the y direction. k : numeric or array_like, optional {:func:`colour.contrast.contrast_sensitivity_function_Barten1999`}, Signal-to-noise (SNR) ratio :math:`k`. n : numeric or array_like, optional {:func:`colour.contrast.contrast_sensitivity_function_Barten1999`}, Quantum efficiency of the eye :math:`n`. p : numeric or array_like, optional {:func:`colour.contrast.contrast_sensitivity_function_Barten1999`}, Photon conversion factor :math:`p` in :math:`photons\\div seconds\\div degrees^2\\div Trolands` that depends on the light source. phi_0 : numeric or array_like, optional {:func:`colour.contrast.contrast_sensitivity_function_Barten1999`}, Spectral density :math:`\\phi_0` in :math:`seconds degrees^2` of the neural noise. sigma : numeric or array_like, optional {:func:`colour.contrast.contrast_sensitivity_function_Barten1999`}, Standard deviation :math:`\\sigma` of the line-spread function resulting from the convolution of the different elements of the convolution process. u : numeric {:func:`colour.contrast.contrast_sensitivity_function_Barten1999`}, Spatial frequency :math:`u`, the cycles per degree. u_0 : numeric or array_like, optional {:func:`colour.contrast.contrast_sensitivity_function_Barten1999`}, Spatial frequency :math:`u_0` in :math:`cycles\\div degrees` above which the lateral inhibition ceases. Returns ------- ndarray Contrast sensitivity :math:`S`. References ---------- :cite:`Barten1999`, :cite:`Barten2003`, :cite:`Cowan2004`, :cite:`InternationalTelecommunicationUnion2015`, Examples -------- >>> contrast_sensitivity_function(u=4) # doctest: +ELLIPSIS 360.8691122... >>> contrast_sensitivity_function('Barten 1999', u=4) # doctest: +ELLIPSIS 360.8691122... """ method = validate_method(method, CONTRAST_SENSITIVITY_METHODS) function = CONTRAST_SENSITIVITY_METHODS[method] S = function(**filter_kwargs(function, **kwargs)) return S
__all__ += ['CONTRAST_SENSITIVITY_METHODS', 'contrast_sensitivity_function']