Index out of bound error when image is given as input on python

[gargsp123]

Hey Ling,thanks for the excellent code.
I tried running your code(python) on the following images,unfortunately for the first one I am getting index out of bound error
The exact is as follows
index 93 is out of bounds for axis 0 with size 93 at line 245 in trace_skeleton

The same happens for this image also
index 63 is out for bounds for axis 0 with size 63 at line 245

And for this image the result is not matching up,any ideas what can be going wrong here