使用 Delaunay 方法创建三角形网格

Question

I'm trying create a triangular mesh using python. As I know the boundary points, I think the delaunay method is more appropriated. I tried use scipy. the code is very simple

from scipy.spatial import Delaunay
pixelpoints = np.transpose(np.nonzero(binaryImage))
tri = Delaunay(pixelpoints)
import matplotlib.pyplot as plt
plt.triplot(pixelpoints[:,0], pixelpoints[:,1], tri.simplices.copy())
plt.plot(pixelpoints[:,0], pixelpoints[:,1], 'o')
plt.show()

But I don't want this. I'd like to mesh inside the image bounds. Also, I don't want to mesh inside the holes. Can I control the number of triangles to cover a surface? Is there an alternative way to do this?

Thank you.

Answer 1

You can easily remove additional triangles using the Polygon.IsPointInside(tCentroid) where tCentroid is the triangle centroid. IsPointInside() can be derived by this: http://geomalgorithms.com/a03-_inclusion.html .

Answer 2

The Triangle program supports both these needs: refining triangles to a prescribed size and removing triangles outside the polygon or in holes. There seems to be a python interface floating around: the API describes how to specify holes and a maximum triangle area.