Web gaps area

Import image

In[]:=
web=
;

tophat transform

lines=ImageLines[Blur[TopHatTransform[web,5]],Method{"Segmented"True}];​​HighlightImage[web5,lines]
Out[]=
In[]:=
MorphologicalGraph[Binarize[Blur[TopHatTransform[web,5]],0.05]]
Out[]=