francescoracciatti / CIEDE2000

CIEDE2000 color distance algorithm

CIEDE2000

CIEDE2000 provides utility functions to:

• calculate the distance between two Lab colors;
• convert colors from BGR to Lab.

Function distance

Calculates the distance between two Lab colors in terms of ΔE₀₀.

Usage example:

from ciede2000 import CIEDE2000

lab1 = (50.0, 2.5, 0.0)
lab2 = (50.0, -1.0, 2.0)
deltaE_00 = CIEDE2000.distance(lab1, lab2)

Function bgr_to_lab

Converts a BGR color to a Lab color.

Usage example:

from ciede2000 import CIEDE2000

bgr = (125, 125, 125)
lab_color = CIEDE2000.bgr_to_lab(bgr)

Test data

The folder data contains spreadsheets with test data:

• lab-distances.xlsx contains test data for the function distance;
• bgr-to-lab.xlsx contains test data for the function bgr_to_lab;

Author

Francesco Racciatti

Acknowledgments

The implementation of Lab colors difference, and the related tests, are based on the paper The CIEDE2000 Color-Difference Formula: Implementation Notes, Supplementary Test Data, and Mathematical Observations, by G. Sharma, W. Wu, E. N. Dalal.

The tests of the BGR to Lab conversion function were built by using
https://www.easyrgb.com/en/convert.php (checked on April 27, 2021).

License

This project is licensed under MIT license.