def mesopic_luminous_efficiency_function(
Lp,
source='Blue Heavy',
method='MOVE',
photopic_lef=PHOTOPIC_LEFS.get(
'CIE 1924 Photopic Standard Observer'),
scotopic_lef=SCOTOPIC_LEFS.get(
'CIE 1951 Scotopic Standard Observer')):
"""
Returns the mesopic luminous efficiency function :math:`V_m(\lambda)` for
given photopic luminance :math:`L_p`.
Parameters
----------
Lp : numeric
Photopic luminance :math:`L_p`.
source : unicode, optional
{'Blue Heavy', 'Red Heavy'},
Light source colour temperature.
method : unicode, optional
{'MOVE', 'LRC'},
Method to calculate the weighting factor.
photopic_lef : SpectralPowerDistribution, optional
:math:`V(\lambda)` photopic luminous efficiency function.
scotopic_lef : SpectralPowerDistribution, optional
:math:`V^\prime(\lambda)` scotopic luminous efficiency function.
Returns
-------
SpectralPowerDistribution
Mesopic luminous efficiency function :math:`V_m(\lambda)`.
Examples
--------
>>> mesopic_luminous_efficiency_function(0.2) # doctest: +ELLIPSIS
<colour.colorimetry.spectrum.SpectralPowerDistribution object at 0x...>
"""
photopic_lef_shape = photopic_lef.shape
scotopic_lef_shape = scotopic_lef.shape
shape = SpectralShape(
max(photopic_lef_shape.start, scotopic_lef_shape.start),
min(photopic_lef_shape.end, scotopic_lef_shape.end),
max(photopic_lef_shape.steps, scotopic_lef_shape.steps))
spd_data = dict((i,
mesopic_weighting_function(
i,
Lp,
source,
method,
photopic_lef,
scotopic_lef))
for i in shape)
spd = SpectralPowerDistribution(
'{0} Lp Mesopic Luminous Efficiency Function'.format(Lp),
spd_data)
return spd.normalise()
def mesopic_luminous_efficiency_function(
Lp,
source='Blue Heavy',
method='MOVE',
photopic_lef=PHOTOPIC_LEFS.get('CIE 1924 Photopic Standard Observer'),
scotopic_lef=SCOTOPIC_LEFS.get('CIE 1951 Scotopic Standard Observer')):
"""
Returns the mesopic luminous efficiency function :math:`V_m(\lambda)` for
given photopic luminance :math:`L_p`.
Parameters
----------
Lp : numeric
Photopic luminance :math:`L_p`.
source : unicode, optional
**{'Blue Heavy', 'Red Heavy'}**,
Light source colour temperature.
method : unicode, optional
**{'MOVE', 'LRC'}**,
Method to calculate the weighting factor.
photopic_lef : SpectralPowerDistribution, optional
:math:`V(\lambda)` photopic luminous efficiency function.
scotopic_lef : SpectralPowerDistribution, optional
:math:`V^\prime(\lambda)` scotopic luminous efficiency function.
Returns
-------
SpectralPowerDistribution
Mesopic luminous efficiency function :math:`V_m(\lambda)`.
Examples
--------
>>> mesopic_luminous_efficiency_function(0.2) # doctest: +ELLIPSIS
<colour.colorimetry.spectrum.SpectralPowerDistribution object at 0x...>
"""
photopic_lef_shape = photopic_lef.shape
scotopic_lef_shape = scotopic_lef.shape
shape = SpectralShape(
max(photopic_lef_shape.start, scotopic_lef_shape.start),
min(photopic_lef_shape.end, scotopic_lef_shape.end),
max(photopic_lef_shape.steps, scotopic_lef_shape.steps))
wavelengths = shape.range()
spd_data = dict(
zip(
wavelengths,
mesopic_weighting_function(wavelengths, Lp, source, method,
photopic_lef, scotopic_lef)))
spd = SpectralPowerDistribution(
'{0} Lp Mesopic Luminous Efficiency Function'.format(Lp), spd_data)
return spd.normalise()
def mesopic_weighting_function(wavelength,
Lp,
source='Blue Heavy',
method='MOVE',
photopic_lef=PHOTOPIC_LEFS.get(
'CIE 1924 Photopic Standard Observer'),
scotopic_lef=SCOTOPIC_LEFS.get(
'CIE 1951 Scotopic Standard Observer')):
"""
Calculates the mesopic weighting function factor at given wavelength
:math:`\lambda` using the photopic luminance :math:`L_p`.
Parameters
----------
wavelength : numeric or array_like
Wavelength :math:`\lambda` to calculate the mesopic weighting function
factor.
Lp : numeric
Photopic luminance :math:`L_p`.
source : unicode, optional
{'Blue Heavy', 'Red Heavy'},
Light source colour temperature.
method : unicode, optional
{'MOVE', 'LRC'},
Method to calculate the weighting factor.
photopic_lef : SpectralPowerDistribution, optional
:math:`V(\lambda)` photopic luminous efficiency function.
scotopic_lef : SpectralPowerDistribution, optional
:math:`V^\prime(\lambda)` scotopic luminous efficiency function.
Returns
-------
numeric or ndarray
Mesopic weighting function factor.
Examples
--------
>>> mesopic_weighting_function(500, 0.2) # doctest: +ELLIPSIS
0.7052200...
"""
mesopic_x_luminance_values = sorted(MESOPIC_X_DATA.keys())
index = mesopic_x_luminance_values.index(
closest(mesopic_x_luminance_values, Lp))
x = MESOPIC_X_DATA.get(
mesopic_x_luminance_values[index]).get(source).get(method)
Vm = ((1 - x) *
scotopic_lef.get(wavelength) + x * photopic_lef.get(wavelength))
return Vm
def mesopic_weighting_function(wavelength,
Lp,
source='Blue Heavy',
method='MOVE',
photopic_lef=PHOTOPIC_LEFS.get(
'CIE 1924 Photopic Standard Observer'),
scotopic_lef=SCOTOPIC_LEFS.get(
'CIE 1951 Scotopic Standard Observer')):
"""
Calculates the mesopic weighting function factor at given wavelength
:math:`\lambda` using the photopic luminance :math:`L_p`.
Parameters
----------
wavelength : numeric or array_like
Wavelength :math:`\lambda` to calculate the mesopic weighting function
factor.
Lp : numeric
Photopic luminance :math:`L_p`.
source : unicode, optional
**{'Blue Heavy', 'Red Heavy'}**,
Light source colour temperature.
method : unicode, optional
**{'MOVE', 'LRC'}**,
Method to calculate the weighting factor.
photopic_lef : SpectralPowerDistribution, optional
:math:`V(\lambda)` photopic luminous efficiency function.
scotopic_lef : SpectralPowerDistribution, optional
:math:`V^\prime(\lambda)` scotopic luminous efficiency function.
Returns
-------
numeric or ndarray
Mesopic weighting function factor.
Examples
--------
>>> mesopic_weighting_function(500, 0.2) # doctest: +ELLIPSIS
0.7052200...
"""
mesopic_x_luminance_values = sorted(MESOPIC_X_DATA.keys())
index = mesopic_x_luminance_values.index(
closest(mesopic_x_luminance_values, Lp))
x = MESOPIC_X_DATA.get(
mesopic_x_luminance_values[index]).get(source).get(method)
Vm = ((1 - x) *
scotopic_lef.get(wavelength) + x * photopic_lef.get(wavelength))
return Vm
def mesopic_weighting_function(wavelength,
Lp,
source='Blue Heavy',
method='MOVE',
photopic_lef=PHOTOPIC_LEFS.get(
'CIE 1924 Photopic Standard Observer'),
scotopic_lef=SCOTOPIC_LEFS.get(
'CIE 1951 Scotopic Standard Observer')):
"""
Calculates the mesopic weighting function factor at given wavelength
:math:`\lambda` using the photopic luminance :math:`L_p`.
Parameters
----------
wavelength : numeric
Wavelength :math:`\lambda` to calculate the mesopic weighting function
factor.
Lp : numeric
Photopic luminance :math:`L_p`.
source : unicode, optional
{'Blue Heavy', 'Red Heavy'},
Light source colour temperature.
method : unicode, optional
{'MOVE', 'LRC'},
Method to calculate the weighting factor.
photopic_lef : SpectralPowerDistribution, optional
:math:`V(\lambda)` photopic luminous efficiency function.
scotopic_lef : SpectralPowerDistribution, optional
:math:`V^\prime(\lambda)` scotopic luminous efficiency function.
Returns
-------
numeric
Mesopic weighting function factor.
Raises
------
KeyError
If wavelength :math:`\lambda` is not available in either luminous
efficiency function.
Examples
--------
>>> mesopic_weighting_function(500, 0.2) # doctest: +ELLIPSIS
0.7052200...
"""
for function in (photopic_lef, scotopic_lef):
if function.get(wavelength) is None:
raise KeyError(
('"{0} nm" wavelength not available in "{1}" '
'luminous efficiency function with "{2}" shape!').format(
wavelength, function.name, function.shape))
mesopic_x_luminance_values = sorted(MESOPIC_X_DATA.keys())
index = mesopic_x_luminance_values.index(
closest(mesopic_x_luminance_values, Lp))
x = MESOPIC_X_DATA.get(
mesopic_x_luminance_values[index]).get(source).get(method)
Vm = ((1 - x) *
scotopic_lef.get(wavelength) + x * photopic_lef.get(wavelength))
return Vm
def mesopic_luminous_efficiency_function(
Lp,
source='Blue Heavy',
method='MOVE',
photopic_lef=PHOTOPIC_LEFS.get(
'CIE 1924 Photopic Standard Observer'),
scotopic_lef=SCOTOPIC_LEFS.get(
'CIE 1951 Scotopic Standard Observer')):
"""
Returns the mesopic luminous efficiency function :math:`V_m(\lambda)` for
given photopic luminance :math:`L_p`.
Parameters
----------
Lp : numeric
Photopic luminance :math:`L_p`.
source : unicode, optional
**{'Blue Heavy', 'Red Heavy'}**,
Light source colour temperature.
method : unicode, optional
**{'MOVE', 'LRC'}**,
Method to calculate the weighting factor.
photopic_lef : SpectralPowerDistribution, optional
:math:`V(\lambda)` photopic luminous efficiency function.
scotopic_lef : SpectralPowerDistribution, optional
:math:`V^\prime(\lambda)` scotopic luminous efficiency function.
Returns
-------
SpectralPowerDistribution
Mesopic luminous efficiency function :math:`V_m(\lambda)`.
Examples
--------
>>> print(mesopic_luminous_efficiency_function(0.2))
SpectralPowerDistribution(\
'0.2 Lp Mesopic Luminous Efficiency Function', (380.0, 780.0, 1.0))
"""
photopic_lef_shape = photopic_lef.shape
scotopic_lef_shape = scotopic_lef.shape
shape = SpectralShape(
max(photopic_lef_shape.start, scotopic_lef_shape.start),
min(photopic_lef_shape.end, scotopic_lef_shape.end),
max(photopic_lef_shape.interval, scotopic_lef_shape.interval))
wavelengths = shape.range()
spd_data = dict(zip(wavelengths,
mesopic_weighting_function(
wavelengths,
Lp,
source,
method,
photopic_lef,
scotopic_lef)))
spd = SpectralPowerDistribution(
'{0} Lp Mesopic Luminous Efficiency Function'.format(Lp),
spd_data)
return spd.normalise()
def mesopic_weighting_function(
wavelength,
Lp,
source='Blue Heavy',
method='MOVE',
photopic_lef=PHOTOPIC_LEFS.get('CIE 1924 Photopic Standard Observer'),
scotopic_lef=SCOTOPIC_LEFS.get('CIE 1951 Scotopic Standard Observer')):
"""
Calculates the mesopic weighting function factor at given wavelength
:math:`\lambda` using the photopic luminance :math:`L_p`.
Parameters
----------
wavelength : numeric
Wavelength :math:`\lambda` to calculate the mesopic weighting function
factor.
Lp : numeric
Photopic luminance :math:`L_p`.
source : unicode
('Blue Heavy', 'Red Heavy'),
Light source colour temperature.
method : unicode
('MOVE', 'LRC'),
Method to calculate the weighting factor.
photopic_lef : SpectralPowerDistribution
:math:`V(\lambda)` photopic luminous efficiency function.
scotopic_lef : SpectralPowerDistribution
:math:`V^\prime(\lambda)` scotopic luminous efficiency function.
Returns
-------
numeric
Mesopic weighting function factor.
Raises
------
KeyError
If wavelength :math:`\lambda` is not available in either luminous
efficiency function.
Examples
--------
>>> mesopic_weighting_function(500, 0.2) # doctest: +ELLIPSIS
0.7052200...
"""
for function in (photopic_lef, scotopic_lef):
if function.get(wavelength) is None:
raise KeyError(
('"{0} nm" wavelength not available in "{1}" '
'luminous efficiency function with "{2}" shape!').format(
wavelength, function.name, function.shape))
mesopic_x_luminance_values = sorted(MESOPIC_X_DATA.keys())
index = mesopic_x_luminance_values.index(
closest(mesopic_x_luminance_values, Lp))
x = MESOPIC_X_DATA.get(
mesopic_x_luminance_values[index]).get(source).get(method)
Vm = ((1 - x) * scotopic_lef.get(wavelength) +
x * photopic_lef.get(wavelength))
return Vm
