Which filter ladder to use with noisey grey-image for Finger(tip) detection

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Hi there,

Attached you will find a picture shot with my camera system. I would like to detect the finger (right hand side of the picture), therefore I think I need to ramp up that picture quality.

->Image which has to be improved!<-

I got best results with Bilateral Blure + Threshold, although best doesn't mean a good or satisfying one. Does someone have an working idea for a filter ladder to get an better image for finger detection out of the given picture? (C/C++ prefered :) )

Sidenote: It has to be running in real time on a Laptop, due to it being a camera stream.

Thanks for your time & help!