How to define constraints on delaunay triangulation

I have a set of boundray points of human foreground and I want the triangle meshes to be inside the boundray

I try the constrianted delaunay triangulation but i didn't know how to define the constriants

this my code

[sPostionX,sPostionY]=find(foregrounds(69).foreground==1);
sPostions=[sPostionX,sPostionY];
boundries=boundary(sPostions,0.97);
plot(sPostions(boundries,1),sPostions(boundries,2));
tri =  DelaunayTri(sPostions(boundries,:));  % Delaunay triangulation
hold on
triplot(tri);

Answer 1

[Naga]

Hi Amal,

To perform Constrained Delaunay Triangulation (CDT) with a set of boundary points, you need to ensure that the triangulation respects the constraints defined by the boundary. MATLAB provides a function called delaunayTriangulation which can be used to achieve CDT by specifying edges that need to be preserved.

Here's how you can modify your code to incorporate constraints:

% Get the boundary indices
boundaries = boundary(sPostions, 0.97);

% Create the edges that represent the boundary
edges = [boundaries, circshift(boundaries, -1)];

% Create a constrained Delaunay triangulation
tri = delaunayTriangulation(sPostions, edges);

% Plot the boundary and triangulation
figure;
plot(sPostions(boundaries, 1), sPostions(boundaries, 2), 'r-', 'LineWidth', 2);
hold on;
triplot(tri);
hold off;

The delaunayTriangulation function takes both the points and the edges, ensuring the triangulation respects the specified constraints.This approach should help you create a triangulation that remains within the specified boundary.