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rgbwide2xyz

Convert wide-gamut RGB color values to CIE 1931 XYZ color values

Since R2020b

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    Syntax

    XYZ = rgbwide2xyz(RGB,BPS)
    XYZ = rgbwide2xyz(RGB,BPS,Name,Value)

    Description

    XYZ = rgbwide2xyz(RGB,BPS) converts wide-gamut RGB values in the BT.2020 or BT.2100 color spaces to CIE 1931 XYZ color values. BPS specifies the number of bits required to represent each input channel.

    example

    XYZ = rgbwide2xyz(RGB,BPS,Name,Value) specifies options using one or more name-value pair arguments.

    Examples

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    Open Live Script

    Convert 10-bit BT.2020 RGB Green Value to XYZ

    Create a wide-gamut RGB value for the color green.

    rgbvalue = uint16([64 940 64]);

    Convert the 10-bit BT.2020 RGB color value to an XYZ color value.

    xyzvalue = rgbwide2xyz(rgbvalue,10);

    Convert 12-bit BT.2100 RGB Blue Value to XYZ

    Create a wide-gamut RGB color value for the color blue.

    rgbvalue = uint16([64 64 940]);

    Convert the 12-bit BT.2100 RGB value to an XYZ color value.

    xyzvalue = rgbwide2xyz(rgbvalue,12,ColorSpace="BT.2100");

    Convert 10-bit BT.2100 RGB White Value to XYZ Using HLG

    Create a wide-gamut RGB value for the color white.

    rgbvalue = uint16([940 940 940]);

    Convert the 10-bit BT.2100 RGB color value to an XYZ color value, using the Hybrid Log Gamma (HLG) transfer function.

    xyzvalue = rgbwide2xyz(rgbvalue,10,ColorSpace="BT.2100",LinearizationFcn="HLG");

    Input Arguments

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    Wide-gamut RGB color values, specified as one of the following:

    • p-by-3 numeric matrix of color values (one color per row)

    • m-by-n-by-3 numeric array representing an image

    • m-by-n-by-3-by-f numeric array representing a stack of images

    The following table shows the data range for wide-gamut, integer color values for 10- and 12-bit data. The minimum value in the range maps to black, and the maximum value in the range maps to white. Only pixels with RGB values within the supported data range for wide-gamut values are guaranteed to be mapped to realizable colors.

    Data TypeFull Data RangeData Range for Wide-Gamut RGB
    10-bit[0, 1023][64, 940]
    12-bit [0, 4095][256, 3760]

    Data Types: uint16

    Bits per sample for each channel of the input wide-gamut RGB image, specified as 10 or 12.

    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: xyzvalue = rgbwide2xyz(rgbvalue,12,ColorSpace="BT.2100"); specifies the color space of the wide-gamut RGB values as "BT.2100".

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

    Example: xyzvalue = rgbwide2xyz(rgbvalue,12,"ColorSpace","BT.2100"); specifies the color space of the wide-gamut RGB values as "BT.2100".

    Color space of the wide-gamut RGB values, specified as "BT.2020" or "BT.2100".

    Data Types: char | string

    Reference white point, specified as a 3-element row vector or one of the CIE standard illuminants listed in the 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 | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | logical | char | string

    Transfer function for transformation, specified as one of these values:

    ValueDescription
    "PQ"Perceptual Quantization
    "HLG"Hybrid Log Gamma

    Data Types: char | string

    Output Arguments

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    Values in the CIE 1931 XYZ color space, returned as a numeric array of the same size as the RGB input color values.

    Data Types: double

    References

    [1] Rec. ITU-R BT.2020-2 (10/2015). "Parameter values for ultra-high definition television systems for production and international programme exchange." International Telecommunication Union; Broadcasting service (television). https://www.itu.int/rec/R-REC-BT.2020.

    [2] Rec. ITU-R BT.2100-2 (07/2018). "Image parameter values for dynamic range television for use in production and international programme exchange." International Telecommunication Union; Broadcasting service (television). https://www.itu.int/rec/R-REC-BT.2100.

    [3] Rec. ITU-R BT.2390-7 (07/2019). "High dynamic range television for production and international programme exchange." International Telecommunication Union; Broadcasting service (television). https://www.itu.int/pub/R-REP-BT.2390.

    Version History

    Introduced in R2020b

    See Also

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