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lab2rgb

Convert CIE 1976 L*a*b* to RGB

Syntax

rgb = lab2rgb(lab)
rgb = lab2rgb(lab,Name,Value)

Description

example

rgb = lab2rgb(lab) converts CIE 1976 L*a*b* values to sRGB values.

example

rgb = lab2rgb(lab,Name,Value) specifies additional conversion options, such as the color space of the RGB image, using one or more name-value pair arguments.

Examples

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Convert a color value in the L*a*b* color space to standard RGB color space.

lab2rgb([70 5 10])
ans = 1×3

    0.7359    0.6566    0.6010

Convert a color value in L*a*b* color space to the Adobe RGB (1998) color space.

lab2rgb([70 5 10],'ColorSpace','adobe-rgb-1998')
ans = 1×3

    0.7086    0.6507    0.5978

Convert an L*a*b* color value to standard RGB specifying the D50 whitepoint.

lab2rgb([70 5 10],'WhitePoint','d50')
ans = 1×3

    0.7282    0.6573    0.6007

Convert an L*a*b* color value to an 8-bit encoded RGB color value.

lab2rgb([70 5 10],'OutputType','uint8')
ans = 1x3 uint8 row vector

   188   167   153

Input Arguments

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L*a*b* color values to convert, specified as a numeric array in one of the following formats.

  • c-by-3 colormap. Each row specifies one XYZ color value.

  • m-by-n-by-3 image

  • m-by-n-by-3-by-p stack of images

Data Types: single | double

Name-Value Pair Arguments

Specify optional comma-separated pairs of Name,Value arguments. Name is the argument name and Value is the corresponding value. Name must appear inside quotes. You can specify several name and value pair arguments in any order as Name1,Value1,...,NameN,ValueN.

Example: lab2rgb([70 5 10],'WhitePoint','d50')

Color space of the output RGB values, specified as the comma-separated pair consisting of 'ColorSpace' and 'srgb', 'adobe-rgb-1998', or 'linear-rgb'. If you specify 'linear-rgb', then lab2rgb returns linearized sRGB values.

Data Types: char

Reference white point, specified as the comma-separated pair consisting of 'WhitePoint' and a 1-by-3 vector or one of the CIE standard illuminants listed in the following table.

ValueWhite Point
'a'

CIE standard illuminant A, [1.0985, 1.0000, 0.3558]. Simulates typical, domestic, tungsten-filament lighting with correlated color temperature of 2856 K. 

'c'CIE standard illuminant C, [0.9807, 1.0000, 1.1822]. Simulates average or north sky daylight with correlated color temperature of 6774 K. Deprecated by CIE.
'e'Equal-energy radiator, [1.000, 1.000, 1.000]. Useful as a theoretical reference.
'd50'CIE standard illuminant D50, [0.9642, 1.0000, 0.8251]. Simulates warm daylight at sunrise or sunset with correlated color temperature of 5003 K. Also known as horizon light.

'd55'

CIE standard illuminant D55, [0.9568, 1.0000, 0.9214]. Simulates mid-morning or mid-afternoon daylight with correlated color temperature of 5500 K.  

'd65'CIE standard illuminant D65, [0.9504, 1.0000, 1.0888]. Simulates noon daylight with correlated color temperature of 6504 K. 
'icc'Profile Connection Space (PCS) illuminant used in ICC profiles. Approximation of [0.9642, 1.000, 0.8249] using fixed-point, signed, 32-bit numbers with 16 fractional bits. Actual value: [31595,32768, 27030]/32768.

Data Types: single | double | char

Data type of returned RGB values, specified as one of the following values: 'double', 'single', 'uint8', or 'uint16'. If you do not specify OutputType, the output type is the same type as the input.

Data Types: char

Output Arguments

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Converted RGB color values, returned as a numeric array of the same shape as the input. The output type is the same as the input type unless you specify the OutputType parameter.

Tips

  • If you specify the output RGB color space as 'linear-rgb', then the output values are linearized sRGB values. If instead you want the output color space to be linearized Adobe RGB (1998), then you can use the rgb2lin function.

    For example, to convert CIE 1976 L*a*b* image LAB to linearized Adobe RGB (1998) color space, perform the conversion in two steps:

    RGBadobe = lab2rgb(LAB,'ColorSpace','adobe-rgb-1998');
    RGBlinadobe = rgb2lin(RGBadobe,'ColorSpace','adobe-rgb-1998');

Extended Capabilities

See Also

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Introduced in R2014b