Branching points(OpenCV,C++)

I want to identify the branching points of the lightning in this image:

http://i.stack.imgur.com/PXujf.jpg

What I did first was threshold the image such that I get the lighning part of the image and discard the backround. This is the result

http://i.stack.imgur.com/IYNTi.jpg

I used the threshold function in openCV and the result开发者_开发技巧ing image is pretty much bad as the quality is lost, the branches are no longer visible.

Ok, basically I have 2 problems:

1. How can i properly segment the image such that the lightning part of the image is properly captured.
2. How can I then, identify the branching points? For every branch point i want to draw a red circle over it.

Thanking you in advance

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Segmentation / thresholding:
I would give this a try. They also had a NIPS2012 workshop (DISCML) paper on image segmentation that seems to handle quite elegantly thin elongated objects (like the lightnings in the picture).

Branching points:
Once you have a good mask you can use morphological operations to extract the branching points (Matlab code):

 bw = myGoodSegmentation( img ); % replace with whatever segmentation/thresholding that works best for you.
 tbw = bwmorph( bw, 'skel', inf );
 [y x] = find( bwmorph( tbw, 'branchpoints' ) ); % get x,y coordinates of branch points