Name

---

    DELTAE

Purpose

---

    This function returns the computed color difference (deltaE)
    between two (2) provided RGB color triplets. The triplets are
    converted to sRGB (0-1), converted to tristimulus values (XYZ),
    converted to CIE L*a*b* where the color difference between them
    is computed using a simple Euclidean distance measure.

Category

---

    Color Science.

Calling Sequence

---

    Result = DELTAE( color1, color2, ILLUMINANT=illuminant,
                                    DL=dL,
                                    DA=dA,
                                    DB=dB,
                                    AVERAGE=average )

Inputs

---

    color1
      A 3-element vector or 3xn array of color triplet values
      with each color value in the range [0,255]
    color2
      A 3-element vector or 3xn array of color triplet values
      with each color value in the range [0,255]

Keyword Parameters

---

    ILLUMINANT
      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)
    DL
      An optional keyword to return a scalar or vector of deltaL value(s)
    DA
      An optional keyword to return a scalar or vector of deltaA value(s)
    DB
      An optional keyword to return a scalar or vector of deltaB value(s)
    AVERAGE
      An optional keyword that will, upon return, contain
      a 4-element vector composed of deltaE, deltaL, deltaA, and
      deltaB

Return Value

---

    Result is either a scalar (if the provided color values
    were single triplets) or an n-element vector (if a series of
    triplets were provided for each color) that contains the color
    difference values.
  :ERROR CHECKING:
    RETURN, -1
      if the provided color data is not of compatible dimensions

Side Effects

---

    None

Requires

---

    SRGB2XYZ
    XYZ2LAB

Modification History

---

    Written by: Carl Salvaggio
    January, 2008 Original code
   

Disclaimer

---

    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.