A New Skeleton Feature Extraction Method for Terrain Model Using Profile Recognition and Morphological Simplification

Algorithm 2

Polygon disassembling.

Input: Feature segments set FS with triangles and

   single edges.

Output: Feature segments set FS without any little triangles.

1. Traverse all of the feature segments:

 1.1 If there is not any case of 4 kinds of triangles of

  Figures 5(a)–5(d) into set T, go to step 5; otherwise

  go to step 1.2;

 1.2 For 𝑡∈𝑇, evaluate whether its three edges are shared;

 1.3 Denote the edge as 2, if it has been shared by

   two triangles; otherwise denote it as 1 and put it

   into set E.

2. Sort edges in set E in ascending order.

3. Remove the edge 𝑒∈𝐸 from FS and E, if 𝑒

 satisfies the conditions as shown in Figures 5(a)–5(d).

4. Go to step 1.

5. Algorithm end.