The CIE94 color difference formula.
de94 = deltaE94(lab1, lab2, k)
The CIE delta E standard is a fundamental tool of color science. The
metric is described in a wide variety of textbooks. It has gone
through a series of refinements over the years. This formula was
defined in 1994. The latest the CIEDE2000 (see deltaE2000).
K is a 3 vector, in the form [kL, kC, kH]. k =[1 1 1] for the basis
conditions (uniform surround field with L*=50, 1000lx illuminance,
homogeneous stimulus >4 degree visual angle, color difference between
0-5 CIELAB units). In the textile industry kL is commonly set to 2.
Default k is [1 1 1];
In our view, when the CIELAB difference between the two colors is
substantially greater than 10, the scale becomes meaningless.
Anything much larger than 10 is just 'BIG'. Values less than 2 are
small.
Based on formulae quoted in Berns' paper in Color Research and
Application, Vol 21(6), 459-472.
Copyright ImagEval Consultants, LLC, 2003.