colour.spectral_uniformity#

colour.spectral_uniformity(sds: Sequence[SpectralDistribution | MultiSpectralDistributions] | SpectralDistribution | MultiSpectralDistributions | ValuesView, use_second_order_derivatives: bool = False) → NDArrayFloat[source]#

Compute the spectral uniformity (or spectral flatness) of the specified spectral distributions.

Spectral uniformity \((r')^2\) is computed as follows:

\(\text{mean}((r'_1)^2, (r'_2)^2, ..., (r'_n)^2)\)

where \((r'_i)^2\) is the first-order derivative, squared, of the reflectance \(r_i\) of a test sample.

Parameters:
Returns:

Spectral uniformity.

Return type:

numpy.ndarray

Warning

The spectral distributions must have the same spectral shape.

References

[DFH+15]

Examples

>>> from colour.quality.datasets import SDS_TCS
>>> spectral_uniformity(SDS_TCS["CIE 1995"].values())
array([9.5514285...e-06, 1.1482142...e-05, 1.8784285...e-05, 2.8711428...e-05,
       3.1971428...e-05, 3.2342857...e-05, 3.3850000...e-05, 3.9925714...e-05,
       4.1333571...e-05, 2.4002142...e-05, 5.7621428...e-06, 1.4757142...e-06,
       9.7928571...e-07, 2.0057142...e-06, 3.7157142...e-06, 5.7678571...e-06,
       7.5557142...e-06, 7.4635714...e-06, 5.7492857...e-06, 3.8692857...e-06,
       3.5407142...e-06, 4.4742857...e-06, 5.6435714...e-06, 7.6371428...e-06,
       1.0171428...e-05, 1.2254285...e-05, 1.4810000...e-05, 1.6517142...e-05,
       1.5430714...e-05, 1.4536428...e-05, 1.4037857...e-05, 1.1587857...e-05,
       1.0743571...e-05, 1.0979285...e-05, 1.0398571...e-05, 8.2971428...e-06,
       6.3057142...e-06, 5.0942857...e-06, 4.8500000...e-06, 5.5371428...e-06,
       6.4128571...e-06, 7.2592857...e-06, 7.7750000...e-06, 7.1607142...e-06,
       6.6635714...e-06, 6.7328571...e-06, 7.5307142...e-06, 1.0733571...e-05,
       1.6234285...e-05, 2.2570714...e-05, 2.7056428...e-05, 2.7781428...e-05,
       2.5025714...e-05, 1.7966428...e-05, 1.0505000...e-05, 5.9657142...e-06,
       3.6421428...e-06, 2.1664285...e-06, 1.2935714...e-06, 8.3642857...e-07,
       7.2500000...e-07, 6.3928571...e-07, 6.6285714...e-07, 8.5571428...e-07,
       1.4507142...e-06, 2.2542857...e-06, 3.4142857...e-06, 4.9864285...e-06,
       6.4907142...e-06, 7.8928571...e-06, 9.1664285...e-06, 9.9521428...e-06,
       9.7664285...e-06, 9.3150000...e-06, 8.9092857...e-06, 8.1578571...e-06,
       6.8935714...e-06, 5.5721428...e-06, 4.4592857...e-06, 3.4778571...e-06,
       2.7650000...e-06, 2.3114285...e-06, 1.7092857...e-06, 1.1771428...e-06,
       9.8428571...e-07, 8.8285714...e-07, 7.4142857...e-07, 7.0142857...e-07,
       7.0857142...e-07, 6.6642857...e-07, 7.5928571...e-07, 8.7000000...e-07,
       8.2714285...e-07, 7.1714285...e-07, 6.6000000...e-07])
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