A C++ library containing a function to determine how similar two colors are. The code here is original, based on the psuedocode written in the paper The CIEDE2000 Color-Difference Formula: Implementation Notes, Supplementary Test Data, and Mathematical Observations, by Gaurav Sharma, Wencheng Wu, and Edul N. Dalal. While this is written in C++ so that I could place it in a namespace, there's nothing C++-specific about the implementation, and so it would be trivial to convert to C if required. The conversion is left as an exercise to the reader.
To Build
make
To Test
make test && ./testCIEDE2000 (Expected output below.)
As I implemented the method from the paper, I commented the code to line up code fragements with lines from the paper for tracability. There are ways to speed up and optimize this algorithm, which have not been attempted.
A test program (testCIEDE2000) is built by default to run the
tests perscribed by the algorithm authors. Tested on OS X 10.10.2,
and Ubuntu 14.04 LTS. Should work on Cygwin/MINGW, though there will likely
need to be edits to the Makefile.
NOTE
The CIEDE2000 algorithm uses colors from the
LAB colorspace, not RGB. In
practice, I've used ImageMagick to convert
color values for use with CIEDE2000, though that not may be entirely correct.
Expected Testing Output
$ ./testCIEDE2000
1: 2.0425 vs 2.0425 PASS
2: 2.8615 vs 2.8615 PASS
3: 3.4412 vs 3.4412 PASS
4: 1.0000 vs 1.0000 PASS
5: 1.0000 vs 1.0000 PASS
6: 1.0000 vs 1.0000 PASS
7: 2.3669 vs 2.3669 PASS
8: 2.3669 vs 2.3669 PASS
9: 7.1792 vs 7.1792 PASS
10: 7.1792 vs 7.1792 PASS
11: 7.2195 vs 7.2195 PASS
12: 7.2195 vs 7.2195 PASS
13: 4.8045 vs 4.8045 PASS
14: 4.8045 vs 4.8045 PASS
15: 4.7461 vs 4.7461 PASS
16: 4.3065 vs 4.3065 PASS
17: 27.1492 vs 27.1492 PASS
18: 22.8977 vs 22.8977 PASS
19: 31.9030 vs 31.9030 PASS
20: 19.4535 vs 19.4535 PASS
21: 1.0000 vs 1.0000 PASS
22: 1.0000 vs 1.0000 PASS
23: 1.0000 vs 1.0000 PASS
24: 1.0000 vs 1.0000 PASS
25: 1.2644 vs 1.2644 PASS
26: 1.2630 vs 1.2630 PASS
27: 1.8731 vs 1.8731 PASS
28: 1.8645 vs 1.8645 PASS
29: 2.0373 vs 2.0373 PASS
30: 1.4146 vs 1.4146 PASS
31: 1.4441 vs 1.4441 PASS
32: 1.5381 vs 1.5381 PASS
33: 0.6377 vs 0.6377 PASS
34: 0.9082 vs 0.9082 PASS