How to generate the hsv cone graph using Matlab?

Hi

I saw the hsv cone graph on Mathworks webpage

https://uk.mathworks.com/help/images/understanding-color-spaces-and-color-space-conversion.html

I am wondering how to generate this graph using Matlab.

Any advices would be great. Doesn't have to be the full code.

Answer 1

[Kevin Holly]

Here is a starting point. I made some modifications from this code:

https://stackoverflow.com/questions/3339692/modeling-hsv-color-space-in-matlab

H = repmat(linspace(0, 1, 100), 100, 1);     % 100-by-100 hues
S = repmat([linspace(0, 1, 50) ...           % 100-by-100 saturations
            linspace(1, 0, 50)].', 1, 100);  %'
V = repmat([ones(1, 50) ...                  % 100-by-100 values
            linspace(1, 0, 50)].', 1, 100);  %'
hsvImage = cat(3, H, S, V);                  % Create an HSV image
C = hsv2rgb(hsvImage);                       % Convert it to an RGB image

% Next, create the conical surface coordinates:

theta = linspace(0, 2*pi, 20);  % Angular points
X = [zeros(1, 20); ...          % X coordinates
     cos(theta); ...
     zeros(1, 20)];
Y = [zeros(1, 20); ...          % Y coordinates
     sin(theta); ...
     zeros(1, 20)];
Z = [2.*ones(2, 20); ...        % Z coordinates
     zeros(1, 20)];

% Finally, plot the texture-mapped surface:
figure
surf(X, Y, Z, C, 'FaceColor', 'texturemap');
axis equal

figure
surf(X(:,1:16), Y(:,1:16), Z(:,1:16), C(1:80,1:80,:), 'FaceColor', 'texturemap');
axis equal
view(30,32) % Adjust camera angle
hold on
patch(X(:,16), Y(:,16), Z(:,16),C(80,80,:)) % add interior purple face
patch(X(:,1), Y(:,1), Z(:,1),[1 0 0]) % add interior red face