colour.colorimetry.transformations Module¶

Colour Matching Functions Transformations¶

Defines various educational objects for colour matching functions transformations:

• RGB_2_degree_cmfs_to_XYZ_2_degree_cmfs()
• RGB_10_degree_cmfs_to_XYZ_10_degree_cmfs()
• RGB_10_degree_cmfs_to_LMS_10_degree_cmfs()
• LMS_2_degree_cmfs_to_XYZ_2_degree_cmfs()

colour.colorimetry.transformations.RGB_2_degree_cmfs_to_XYZ_2_degree_cmfs(wavelength)[source]¶

Converts Wright & Guild 1931 2 Degree RGB CMFs colour matching functions into the CIE 1931 2 Degree Standard Observer colour matching functions.

Parameters:	wavelength (numeric) – Wavelength \(\lambda\) in nm.
Returns:	CIE 1931 2 Degree Standard Observer spectral tristimulus values.
Return type:	ndarray, (3,)
Raises:	KeyError – If wavelength \(\lambda\) is not available in the colour matching functions.

See also

colour.colorimetry.dataset.cmfs.RGB_CMFS

Notes

• Data for the CIE 1931 2 Degree Standard Observer already exists, this definition is intended for educational purpose.

References

[1]	Wyszecki & Stiles, Color Science - Concepts and Methods Data and Formulae - Second Edition, Wiley Classics Library Edition, published 2000, ISBN-10: 0-471-39918-3, pages 138, 139.

Examples

>>> RGB_2_degree_cmfs_to_XYZ_2_degree_cmfs(700)  
array([ 0.0113577...,  0.004102  ,  0.        ])

colour.colorimetry.transformations.RGB_10_degree_cmfs_to_XYZ_10_degree_cmfs(wavelength)[source]¶

Converts Stiles & Burch 1959 10 Degree RGB CMFs colour matching functions into the CIE 1964 10 Degree Standard Observer colour matching functions.

Parameters:	wavelength (numeric) – Wavelength \(\lambda\) in nm.
Returns:	CIE 1964 10 Degree Standard Observer spectral tristimulus values.
Return type:	ndarray, (3,)
Raises:	KeyError – If wavelength \(\lambda\) is not available in the colour matching functions.

See also

colour.colorimetry.dataset.cmfs.RGB_CMFS

Notes

• Data for the CIE 1964 10 Degree Standard Observer already exists, this definition is intended for educational purpose.

References

[2]	Wyszecki & Stiles, Color Science - Concepts and Methods Data and Formulae - Second Edition, Wiley Classics Library Edition, published 2000, ISBN-10: 0-471-39918-3, page 141.

Examples

>>> RGB_10_degree_cmfs_to_XYZ_10_degree_cmfs(700)  
array([  9.6432150...e-03,   3.7526317...e-03,  -4.1078830...e-06])

colour.colorimetry.transformations.RGB_10_degree_cmfs_to_LMS_10_degree_cmfs(wavelength)[source]¶

Converts Stiles & Burch 1959 10 Degree RGB CMFs colour matching functions into the Stockman & Sharpe 10 Degree Cone Fundamentals spectral sensitivity functions.

Parameters:	wavelength (numeric) – Wavelength \(\lambda\) in nm.
Returns:	Stockman & Sharpe 10 Degree Cone Fundamentals spectral tristimulus values.
Return type:	ndarray, (3,)
Raises:	KeyError – If wavelength \(\lambda\) is not available in the colour matching functions.

Notes

• Data for the Stockman & Sharpe 10 Degree Cone Fundamentals already exists, this definition is intended for educational purpose.

References

[3]	CIE 170-1:2006 Fundamental Chromaticity Diagram with Physiological Axes - Part 1

Examples

>>> RGB_10_degree_cmfs_to_LMS_10_degree_cmfs(700)  
array([ 0.0052860...,  0.0003252...,  0.        ])

colour.colorimetry.transformations.LMS_2_degree_cmfs_to_XYZ_2_degree_cmfs(wavelength)[source]¶

Converts Stockman & Sharpe 2 Degree Cone Fundamentals colour matching functions into the CIE 2012 2 Degree Standard Observer colour matching functions.

Parameters:	wavelength (numeric) – Wavelength \(\lambda\) in nm.
Returns:	CIE 2012 2 Degree Standard Observer spectral tristimulus values.
Return type:	ndarray, (3,)
Raises:	KeyError – If wavelength \(\lambda\) is not available in the colour matching functions.

Notes

• Data for the CIE 2012 2 Degree Standard Observer already exists, this definition is intended for educational purpose.

References

[4]	http://www.cvrl.org/database/text/cienewxyz/cie2012xyz2.htm (Last accessed 25 June 2014)

Examples

>>> LMS_2_degree_cmfs_to_XYZ_2_degree_cmfs(700)  
array([ 0.0109677...,  0.0041959...,  0.        ])