HandyAR finger tip detection and tracking
What does 'successful configuration over time' mean?...  why are there false positives.
I am not able to understand properly how does it handle large movements


they are repeatedly scanning a similar form, the "hand blob", so any outliers from the usual successful input will hopefully be ignored. (maybe if someone nearby passes you something and it thinks their hand is yours for a few frames) 

the paper says they register the "hand blob" or centroid of skin color as an easier tracking target for large movements. the "one time calibration" is probably about where your hand is, and it's predominant shade, in relation to the device. then it makes sure the fingers are there and orientates using the thumb. there is no difference to the formula for large movements except where Ci+1 actually is compared to Ci. 

I really am looking forward to real time interaction with augmented reality. 
are there many more papers you know of like this? id love to read them too.

Edit: hello again raphael.  this is someone of my lvl of understanding and the attempt has been made to fill all of the exceedingly strict criteria for a simple question. this guy is interested, like many are, but has been told off and deleted by you lot before. i can tell.