The cielab2xyz function calculates the transformation of CIE L^*a^*b^* chromaticity coordinates to CIE 1931 x,y,z chromaticity coordinates. Any errors in the data set or in results generated with the Lighting Toolbox are not in the liability of the CIE nor me, see licence.
Usage:
xyz = cielab2xyz(lab,'wp','system')
Where:
| Parameter | Description |
xyz | Are the resulting CIE 1931 xyz chromaticity coordinates. |
lab | Are the given CIE L^*a^*b^* chromaticity coordinates. |
'wp' | Specifies the reference whitepoint, see list below or use a vector triplet [x y z]. Default: ‘D65’ |
'system' | CIE xyz observer: ‘xyz’ = 2° observer (default) ‘xyz10’ = 10° observer |
Reference whitepoints:
| Reference | Description |
'A' | standard illuminant A |
'C' | not official standard illuminant |
'D65' | standard illuminant daylight 6500 K |
'D50' | illuminant daylight 5000 K – D65 recommended |
'D55' | illuminant daylight 5500 K – D65 recommended |
'D75' | illuminant daylight 7500 K – D65 recommended |
'DXX' | lluminant daylight XX00 K – not official standard |
'DXXXX' | illuminant daylight XXXX K – not official standard |
'FL1' | standard illuminant FL1: standard flourescent lamp |
'FL2' | standard illuminant FL2: standard flourescent lamp – recommended |
'FL3' | standard illuminant FL3: standard flourescent lamp |
'FL4' | standard illuminant FL4: standard flourescent lamp |
'FL5' | standard illuminant FL5: standard flourescent lamp |
'FL6' | standard illuminant FL6: standard flourescent lamp |
'FL7' | standard illuminant FL7: broadband flourescent lamp – recommended |
'FL8' | standard illuminant FL8: broadband flourescent lamp |
'FL9' | standard illuminant FL9: broadband flourescent lamp |
'FL10' | standard illuminant FL10: narrow band flourescent lamp |
'FL11' | standard illuminant FL11: narrow band flourescent lamp – recommended |
'FL12' | standard illuminant FL12: narrow band flourescent lamp |
'FL3.1' | standard illuminant FL3.1: standard halophosphat lamp |
'FL3.2' | standard illuminant FL3.2: standard halophosphat lamp |
'FL3.3' | standard illuminant FL3.3: standard halophosphat lamp |
'FL3.4' | standard illuminant FL3.4: DeLuxe type lamp |
'FL3.5' | standard illuminant FL3.5: DeLuxe type lamp |
'FL3.6' | standard illuminant FL3.6: DeLuxe type lamp |
'FL3.7' | standard illuminant FL3.7: three band fluorescent lamp |
'FL3.8' | standard illuminant FL3.8: three band fluorescent lamp |
'FL3.9' | standard illuminant FL3.9: three band fluorescent lamp |
'FL3.10' | standard illuminant FL3.10: three band fluorescent lamp |
'FL3.11' | standard illuminant FL3.11: three band fluorescent lamp |
'FL3.12' | standard illuminant FL3.12: multi band fluorescent lamp |
'FL3.13' | standard illuminant FL3.13: multi band fluorescent lamp |
'FL3.14' | standard illuminant FL3.14: multi band fluorescent lamp |
'FL3.15' | standard illuminant FL3.15: D65 simulator lamp |
'HP1' | standard illuminant HP1: standard high pressure sodium lamp |
'HP2' | standard illuminant HP2: colour enhanced high pressure sodium lamp |
'HP3' | standard illuminant HP3: standard high pressure metal halide lamp |
'HP4' | standard illuminant HP4: standard high pressure metal halide lamp |
'HP5' | standard illuminant HP5: standard high pressure metal halide lamp |
'LED-B1' | Phosphor-type LED |
'LED-B2' | Phosphor-type LED |
'LED-B3' | Phosphor-type LED |
'LED-B4' | Phosphor-type LED |
'LED-B5' | Phosphor-type LED |
'LED-BH1' | Hybrid-type LED |
'LED-RGB1' | RGB-type LED |
'LED-V1' | violet pumped phosphor-type LED |
'LED-V2' | violet pumped phosphor-type LED |
Example:
Transformation of CIE 1976 L^*a^*b^* to CIE 1931 x,y,z chromaticity and back:
lab = [65 -18 2] xyz = cielab2xyz(lab) lab = ciexyz2lab(xyz)
See also: ciexyz2lab
Result:
lab = 65 -18 2 xyz = 0.2761 0.3405 0.3550 lab = 65.0000 -18.0000 2.0000
Transformation of CIE 1976 L^*a^*b^* to CIE 1931 x,y,z chromaticity and back using reference whitepoint ‘A’:
lab = [65 -18 2] xyz = cielab2xyz(lab,'A') lab = ciexyz2lab(xyz,'A')
See also: ciexyz2lab
Result:
lab = 65 -18 2 xyz = 0.3191 0.3405 0.1160 lab = 65.0000 -18.0000 2.0000
Transformation of CIE 1976 L^*a^*b^* to CIE 1931 x,y,z chromaticity and back using reference whitepoint ‘D50’ and CIE xyz 10° observer:
lab = [65 -18 2] xyz10 = cielab2xyz(lab,'D50','xyz10') lab = ciexyz2lab(xyz10,'D50','xyz10')
See also: ciexyz2lab
Result:
lab = 65 -18 2 xyz10 = 0.2810 0.3405 0.2653 lab = 65.0000 -18.0000 2.0000
Reference: