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    This function returns the converted CIE L*a*b* values for a
    provided tristimulus value assuming a particular illuminant,
      L* = 116 * f( Y / Yw ) - 16
      a* = 500 * [f( X / Xw ) - f( Y / Yn )]
      b* = 200 * [f( Y / Yw ) - f( Z / Zn )]
      f(x) = x^(1/3) for x > 0.008856
      f(x) = 7.787 * x + 16/116 for x <= 0.008856


    Color Science.

Calling Sequence

    Result = XYZ2LAB( xyz, ILLUMINANT=illuminant )


      A 3-element vector or 3xn array of tristimulus values

Keyword Parameters

      An optional keyword to describe the illuminant that should
      be used for the XYZ to CIE L*a*b* conversion
          0 - D65 (Daylight) [DEFAULT]
          1 - Illuminant A (Tungsten)
          2 - Illuminant F2 (Cool White Fluorescent)
          3 - Illuminant F11 (Narrow Band Fluorescent)
          4 - Illuminant F7 (Daylight Fluorescent)
          5 - Illuminant F8 (Daylight Fluorescent)

Return Value

    Result is either a 3-element vector or a 3xn array that contains
    the computed CIE L*a*b* coordinates

Side Effects


Modification History

    Written by: Carl Salvaggio
    January, 2008 Original code
    April, 2012 Corrected white reference scaling error


    This source code is provided "as is" and without warranties as to performance
    or merchantability. The author and/or distributors of this source code may
    have made statements about this source code. Any such statements do not
    constitute warranties and shall not be relied on by the user in deciding
    whether to use this source code.
    This source code is provided without any express or implied warranties
    whatsoever. Because of the diversity of conditions and hardware under which
    this source code may be used, no warranty of fitness for a particular purpose
    is offered. The user is advised to test the source code thoroughly before
    relying on it. The user must assume the entire risk of using the source code.

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