colour.contrast_sensitivity_function#

colour.contrast_sensitivity_function(method: Literal['Barten 1999'] | str = 'Barten 1999', **kwargs) → NDArrayFloat[source]#

Return the contrast sensitivity \(S\) of the human eye according to the contrast sensitivity function (CSF) described by given method.

Parameters:

method (Literal['Barten 1999'] | str) – Computation method.
E – {colour.contrast.contrast_sensitivity_function_Barten1999()}, Retinal illuminance \(E\) in Trolands.
k – {colour.contrast.contrast_sensitivity_function_Barten1999()}, Signal-to-noise (SNR) ratio \(k\).
n – {colour.contrast.contrast_sensitivity_function_Barten1999()}, Quantum efficiency of the eye \(n\).
N_max – {colour.contrast.contrast_sensitivity_function_Barten1999()}, Maximum number of cycles \(N_{max}\) over which the eye can integrate the information.
p – {colour.contrast.contrast_sensitivity_function_Barten1999()}, Photon conversion factor \(p\) in \(photons\div seconds\div degrees^2\div Trolands\) that depends on the light source.
phi_0 – {colour.contrast.contrast_sensitivity_function_Barten1999()}, Spectral density \(\phi_0\) in \(seconds degrees^2\) of the neural noise.
sigma – {colour.contrast.contrast_sensitivity_function_Barten1999()}, Standard deviation \(\sigma\) of the line-spread function resulting from the convolution of the different elements of the convolution process.
T – {colour.contrast.contrast_sensitivity_function_Barten1999()}, Integration time \(T\) in seconds of the eye.
u – {colour.contrast.contrast_sensitivity_function_Barten1999()}, Spatial frequency \(u\), the cycles per degree.
u_0 – {colour.contrast.contrast_sensitivity_function_Barten1999()}, Spatial frequency \(u_0\) in \(cycles\div degrees\) above which the lateral inhibition ceases.
X_0 – {colour.contrast.contrast_sensitivity_function_Barten1999()}, Angular size \(X_0\) in degrees of the object in the x direction.
Y_0 – {colour.contrast.contrast_sensitivity_function_Barten1999()}, Angular size \(Y_0\) in degrees of the object in the y direction.
X_max – {colour.contrast.contrast_sensitivity_function_Barten1999()}, Maximum angular size \(X_{max}\) in degrees of the integration area in the x direction.
Y_max – {colour.contrast.contrast_sensitivity_function_Barten1999()}, Maximum angular size \(Y_{max}\) in degrees of the integration area in the y direction.

Returns:

Contrast sensitivity \(S\).

Return type:

numpy.ndarray

References

[Bar99], [Bar03], [CKMW04], [InternationalTUnion15c],

Examples

>>> contrast_sensitivity_function(u=4)  
360.8691122...
>>> contrast_sensitivity_function("Barten 1999", u=4)  
360.8691122...