Is there a function to draw the cie chromaticity diagram ?

Is there a function to draw the CIE chromaticity diagram ?

How to use plotChromaticity ?

Answer 1

[Vishnu Baba Sundaresan]

Use plotChromaticity() function in MATLAB 2017b and above. If you would loci of data, use plot command where variables cie_x and cie_y contain data relevant to your image.

figure(1);
plotChromaticity();
hold on;

h1 = plot(cie_x, cie_y);
legend(h1,{'legend_text1'})

[Thomas Hoffend]

The built-in function plotChromaticity as well as other submissions to the file exchange (e.g. the Computational Color Science package linked below) create plots that have distortion at the edge of and extending outside of the color gamut.

Distorted figure from plotChromaticity:

Better figure (custom color space for a specific device illuminated by a RGB LED):

There is still some distortion outside the gamut for the "better" plot that becomes more visible depending on the color space used. I think there is a way to improve this (working on it). Some of the visible distortion along the CMY radial lines is from the way that I meshed the xy color space and becomes less visible with a higher number of triangles in my mesh. Also it might be desired to decrease saturation a bit going from the white point out to the edges of the gamut.

Anything outside the gamut is really am employment of artistic license. The point is to try to make something that looks good and natural for plotting color data.

[Youngkyu Bae]

May I ask you how can I make a better color gamut image in MATLAB?

Answer 2

[KSSV]

https://in.mathworks.com/matlabcentral/fileexchange/29620-cie-coordinate-calculator

[Ole]

Looks like the the chromaticity diagram is not generated there but read from image.