Python Script to convert color from RGB ColorSpace to CIE Lab Color Space

rgb2Lab.py

import numpy as np

def func(t):
    if (t > 0.008856):
        return np.power(t, 1/3.0);
    else:
        return 7.787 * t + 16 / 116.0;

#Conversion Matrix
matrix = [[0.412453, 0.357580, 0.180423],
          [0.212671, 0.715160, 0.072169],
          [0.019334, 0.119193, 0.950227]]

# RGB values lie between 0 to 1.0
rgb = [1.0, 0, 0] # RGB

cie = np.dot(matrix, rgb);

cie[0] = cie[0] /0.950456;
cie[2] = cie[2] /1.088754; 

# Calculate the L
L = 116 * np.power(cie[1], 1/3.0) - 16.0 if cie[1] > 0.008856 else 903.3 * cie[1];

# Calculate the a 
a = 500*(func(cie[0]) - func(cie[1]));

# Calculate the b
b = 200*(func(cie[1]) - func(cie[2]));

#  Values lie between -128 < b <= 127, -128 < a <= 127, 0 <= L <= 100 
Lab = [b , a, L]; 

# OpenCV Format
L = L * 255 / 100;
a = a + 128;
b = b + 128;
Lab_OpenCV = [b , a, L];