I'm trying to do some analysis of a curly human hair on an iPhone app. I've been using the openCV library.
Particularly I want to be able to estimate the length of the hair, and locate its end points (a measure of curliness is stretched end-to-end length vs. relaxed end-to-end length).
My approach so far has been to use a canny edge detector to find the hair. Then to dilate the result. Finally to skeletonise the image and consider the ends to be those pixels that only have one neighbour. Since the resulting image would hopefully be a one pixel thick line, I could just count the pixels to estimate the length (and maybe adjust for diagonal movements).
The trouble is when the hair is so curly it crosses itself. This makes the skeletonisation add in extra branches and rings that mess up the results.
Is there a better approach for very curly hairs?