Air Writing with Vision Cameras

Rather than using Kinect or Leap Motion which are specifically for gesture, air writing also can be developed with cameras that could feed data to a computer seamlessly. A ordinary web cam is a typical example but needed hard effort. But it's seems like web cams are going to be (or already) replaced by 3D cameras such like Intel RealSense and Creative Senz3D. They can work as ordinary web cams while supporting lot of other requirements such like facial recognition and gesture.

Following are few resources that can be found on web sphere which uses other kind of consumer vision sensor cameras apart from Leap Motion and Kinect.

Writing-in-the-air System Based on Intel RealSense Camera

By Kunpeng Li

Microsoft Research TechFest: Write in The Air

http://research.microsoft.com/en-us/news/asia/features/ciw_writingair.aspx

By Lei Ma et al

A novel video based finger writing virtual character recognition system
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.486.2330&rep=rep1&type=pdf.
By Lianwen Jin et al

A HilbertWarping Method for Camera-based Finger-writing Recognition
http://www.toriwaki.nuie.nagoya-u.ac.jp/publications/318-pdf.pdf.
By Hiroyuki Ishida et al



Video Based Handwritten Characters Recognition
http://www.intechopen.com/books/characterrecognition/video-based-handwritten-characters-recognition
By Chen-Chiung Hsieh



Touchless Writer: Recognizing various Hand Gestures using Artificial Neural Network (ANN) through Webcam And Objects.
http://www.ijafrc.org/Volume2/ncrtit2015/114.pdf.
By Aditya G. Joshi et. al.
This discusses much about using Kinect device on air writing.



Ligature Modeling for Recognition of Characters Written in 3D Space
https://hal.archives-ouvertes.fr/inria-00105116/document.
By Dae Hwan Kim et al



Gesture based Character Recognition
http://web.cse.ohio-state.edu/~moharrer/PDFs/Moharreri_Tayal.pdf.
By Kayhan Moharreri et al



Novel Spatio-temporal Features for Fingertip Writing Recognition in Egocentric Viewpoint http://www.iis.ee.ic.ac.uk/icvl/doc/mva15.pdf.
By Muhammad Zaid Hameed et al
This uses Creative Senz3D Camera



Hand Motion Tracking for Alphabet Recognition using ANN
http://research.ijcaonline.org/volume83/number4/pxc3892580.pdf.
By Shivganga Udhan et al



Vision-Based Handwriting Recognition for Unrestricted Text Input in Mid-Air
http://akme-a2.iosb.fraunhofer.de/EatThisGoogleScholar/d/2012_Vision-based%20handwriting%20recognition%20for%20unrestricted%20text%20input%20in%20mid-air.pdf.
By Alexander Schick et al



Touchless Writer: Object Tracking & Neural Network Recognition
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.598.1996&rep=rep1&type=pdf.
Yang Wu et al