I need help verifying the correctness of a few color
space conversion functions...
For the Color Transformation Language interpreter, I have
implemented a set of functions that convert between RGB,
CIE 1931 XYZ, CIE 1976 L*u*v* and CIE 1976 L*a*b*, but
I don't have a test data set that would allow me to check
if my conversions are correct. Does anyone have such a
data set that they would be willing to share?
Alternatively, if anyone has a program that does color space
conversions, I would really appreciate help verifying that
the table below is correct:
R G B X Y Z L* u* v* a*
b*
1.0 0.0 0.0 41.239 21.264 1.933 53.237 175.010 37.765 80.090
67.203
0.0 1.0 0.0 35.758 71.518 11.920 87.736 -83.067 107.418 -86.182
83.187
0.0 0.0 1.0 18.048 7.219 95.053 32.301 -9.402 -130.351 79.195
-107.855
1.0 1.0 1.0 95.046 100.000 108.906 100.000 0.000 0.000 0.000
0.000
0.005 0.005 0.005 0.475 0.500 0.545 4.516 0.000 0.000 0.000
0.000
0.0 0.0 0.0 0.000 0.000 0.000 0.000 undefined undefined 0.000
0.000
The table was constructed assuming that the CIE xy coordinates
for the red, green and blue primaries and the white point are
as specified in Recommendation ITU-R BT.709-3:
x y
red 0.6400 0.3300
green 0.3000 0.6000
blue 0.1500 0.0600
white 0.3127 0.3290
I assumed that the RGB triple (1, 1, 1) has a luminance of
100 candelas per square meter.
The values of Xn, Yn, and Zn used in calculating L*u*v* and
L*a*b* are 95.0456, 100.000 and 108.906 respectively.
Florian