How to obtain the axis of the skeleton line from any Polygon

How to obtain the skeleton line/axis from any Polygon

After a period of research, there are several ways to obtain the skeleton line of a polygon:

1. The skeleton line can be obtained through the line of the circle center of the contour garden. This method is introduced in the <computer vision-a modern method> book. I compared it and found that the performance is poor. Therefore, give up in-depth research on this method.

Reference website
Http://www.mpi-sb.mpg.de /~ Shin/research/ccurve/node19.html
Reference Code
Http://www.mpi-inf.mpg.de /~ Shin/java_applets/(Java code that can be downloaded)
For more information about the algorithm principles, see the article.
Pose estimation of Human Body Based on silhouette images, IEEE

2. the contour line is drawn from the intersection of the normal line.
Reference website
Http://www.mpi-sb.mpg.de /~ Shin/research/ccurve/node1_html

3. the skeleton line is obtained through the midline connection of the triangle. This algorithm has the smallest amount of computation and provides examples. However, it seems that it is not suitable for distinguishing the interior and exterior of a closed contour, prepare to write for yourself how to obtain the Cartesian triangle,
Algorithm reference:
Http: // 221.232.129.67/garden/Courseware/GIS/CH5/5.6.2.htm

Http://www.geoxd.com/graphic_idl_TIN.htm

References
Research on Automatic Search Algorithm of polygon skeleton line and shape Center