colour.models.ipt Module¶
IPT Colourspace¶
Defines the IPT colourspace transformations:
And computation of correlates:
References
[1] | Fairchild, M. D. (2013). IPT Colourspace. In Color Appearance Models (3rd ed., pp. 8492–8567). Wiley. ISBN:B00DAYO8E2 |
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colour.models.ipt.
IPT_XYZ_TO_LMS_MATRIX
= array([[ 0.4002, 0.7075, -0.0807], [-0.228 , 1.15 , 0.0612], [ 0. , 0. , 0.9184]])¶ CIE XYZ tristimulus values to IPT colourspace normalised cone responses matrix.
IPT_XYZ_TO_LMS_MATRIX : array_like, (3, 3)
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colour.models.ipt.
IPT_LMS_TO_XYZ_MATRIX
= array([[ 1.85024294, -1.13830164, 0.23843496], [ 0.36683078, 0.64388454, -0.01067344], [ 0. , 0. , 1.08885017]])¶ IPT colourspace normalised cone responses to CIE XYZ tristimulus values matrix.
IPT_LMS_TO_XYZ_MATRIX : array_like, (3, 3)
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colour.models.ipt.
IPT_LMS_TO_IPT_MATRIX
= array([[ 0.4 , 0.4 , 0.2 ], [ 4.455 , -4.851 , 0.396 ], [ 0.8056, 0.3572, -1.1628]])¶ IPT colourspace normalised cone responses to IPT colourspace matrix.
IPT_LMS_TO_IPT_MATRIX : array_like, (3, 3)
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colour.models.ipt.
IPT_IPT_TO_LMS_MATRIX
= array([[ 1. , 0.09756893, 0.20522643], [ 1. , -0.11387649, 0.13321716], [ 1. , 0.03261511, -0.67688718]])¶ IPT colourspace to IPT colourspace normalised cone responses matrix.
IPT_IPT_TO_LMS_MATRIX : array_like, (3, 3)
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colour.models.ipt.
XYZ_to_IPT
(XYZ)[source]¶ Converts from CIE XYZ tristimulus values to IPT colourspace.
Parameters: XYZ (array_like) – CIE XYZ tristimulus values. Returns: IPT colourspace array. Return type: ndarray Notes
- Input CIE XYZ tristimulus values needs to be adapted for CIE Standard Illuminant D Series D65.
Examples
>>> XYZ = np.array([0.96907232, 1, 1.12179215]) >>> XYZ_to_IPT(XYZ) array([ 1.0030082..., 0.0190691..., -0.0136929...])
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colour.models.ipt.
IPT_to_XYZ
(IPT)[source]¶ Converts from IPT colourspace to CIE XYZ tristimulus values.
Parameters: IPT (array_like) – IPT colourspace array. Returns: CIE XYZ tristimulus values. Return type: ndarray Examples
>>> IPT = np.array([1.00300825, 0.01906918, -0.01369292]) >>> IPT_to_XYZ(IPT) array([ 0.9690723..., 1. , 1.1217921...])