Secondary Chromaticity Coordinates Computation

secondary_chromaticities_computation.py

P = np.array(
    [[0.6650, 0.3220],
     [0.2950, 0.6070],
     [0.1500, 0.0600]])

W = np.array([0.3127, 0.3290])

NPM = colour.normalised_primary_matrix(P, W)
NPM_i = np.linalg.inv(NPM)

R = np.ravel(NPM)[3:6] # This is the Luminance ratios.
print(R)
# [ 0.20076008  0.72604503  0.07319489]

xyY_red = np.hstack((P[0], R[0]))
print(xyY_red)
# [ 0.66500000  0.32200000  0.20076008]

xyY_green = np.hstack((P[1], R[1]))
print(xyY_green)
# [ 0.29500000  0.60700000  0.72604503]


RGB_red = colour.XYZ_to_RGB(colour.xyY_to_XYZ(xyY_red),
                            W,
                            W,
                            XYZ_to_RGB_matrix=NPM_i)
RGB_green = colour.XYZ_to_RGB(colour.xyY_to_XYZ(xyY_green),
                            W,
                            W,
                            XYZ_to_RGB_matrix=NPM_i)

xy_yellow = colour.XYZ_to_xy(
    colour.RGB_to_XYZ(RGB_red + RGB_green,
                     W,
                     W,
                     NPM))

print(xy_yellow)
# [ 0.42177907  0.50934585]
# Spreadsheet: 0,4218	0,5093