xyz2rgb

Convert CIE 1931 XYZ to RGB

Syntax

RGB = xyz2rgb(XYZ)

RGB = xyz2rgb(XYZ,Name,Value)

Description

RGB = xyz2rgb(XYZ) converts CIE 1931 XYZ values (2° observer) to sRGB values.

RGB = xyz2rgb(XYZ,Name,Value) specifies additional conversion options, such as the color space of the RGB image, using one or more name-value arguments.

Examples

Convert XYZ color to sRGB

Convert a color value in the XYZ color space to the sRGB color space.

xyz2rgb([0.25 0.40 0.10])

ans = 1×3

    0.4174    0.7434    0.2152

Convert XYZ Color to Adobe RGB

Convert the color value in XYZ color space to the Adobe RGB (1998) color space.

xyz2rgb([0.25 0.40 0.10],'ColorSpace','adobe-rgb-1998')

ans = 1×3

    0.5323    0.7377    0.2730

Convert XYZ color to sRGB Specifying Whitepoint

Convert an XYZ color value to sRGB specifying the D50 whitepoint.

xyz2rgb([0.25 0.40 0.10],'WhitePoint','d50')

ans = 1×3

    0.3276    0.7517    0.2869

Convert XYZ color to 8-bit-encoded RGB Color

Convert an XYZ color value to an 8-bit encoded RGB color value.

xyz2rgb([0.25 0.40 0.10],'OutputType','uint8')

ans = 1x3 uint8 row vector

   106   190    55

Input Arguments

XYZ — XYZ color values

numeric array

XYZ 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 Arguments

Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Example: rgb = xyz2rgb([0.25 0.40 0.10],ColorSpace="adobe-rgb-1998")

Before R2021a, use commas to separate each name and value, and enclose Name in quotes.

Example: rgb = xyz2rgb([0.25 0.40 0.10],"ColorSpace","adobe-rgb-1998")

ColorSpace — Color space of output RGB values

"srgb" (default) | "adobe-rgb-1998" | "prophoto-rgb" | "linear-rgb"

Color space of the output RGB values, specified as "srgb", "adobe-rgb-1998", "prophoto-rgb", or "linear-rgb". If you specify "linear-rgb", then xyz2rgb returns linearized sRGB values.

Data Types: string | char

WhitePoint — Reference white point

"d65" (default) | "a" | "c" | "e" | "d50" | "d55" | "icc" | 1-by-3 vector

Reference white point, specified as a 1-by-3 vector or one of the CIE standard illuminants listed in the table.

Value	White 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 | string | char

OutputType — Data type of returned RGB values

"double" | "single" | "uint8" | "uint16"

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

Data Types: string | char

Output Arguments

RGB — Converted RGB color values

numeric array

Converted RGB color values, returned as a numeric array of the same size 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 1931 XYZ image XYZ to linearized Adobe RGB (1998) color space, perform the conversion in two steps:

  RGBadobe = xyz2rgb(XYZ,"ColorSpace","adobe-rgb-1998");
  RGBlinadobe = rgb2lin(RGBadobe,"ColorSpace","adobe-rgb-1998");

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using MATLAB® Coder™.

Usage notes and limitations:

• xyz2rgb supports the generation of C code (requires MATLAB^® Coder™). For more information, see Code Generation for Image Processing.

• If Whitepoint is a character vector, it must be compile-time constant.

• ColorSpace and OutputType must be compile-time constants.

Version History

Introduced in R2014b

R2024b: Generate C code using MATLAB Coder

xyz2rgb now supports the generation of C code (requires MATLAB Coder).

R2022b: Support for ProPhoto (ROMM RGB) color space

xyz2rgb now supports the ProPhoto (ROMM RGB) color space, which has a wider gamut than the sRGB and Adobe RGB 1998 color spaces. To use the ProPhoto color space, specify the ColorSpace name-value argument as "prophoto-rgb".