Vision-based handwriting recognition for unrestricted text input in mid-air

We propose a vision-based system that recognizes handwriting in mid-air. The system does not depend on sensors or markers attached to the users and allows unrestricted character and word input from any position. It is the result of combining handwriting recognition based on Hidden Markov Models with multi-camera 3D hand tracking. We evaluated the system for both quantitative and qualitative aspects. The system achieves recognition rates of 86:15% for character and 97:54% for small-vocabulary isolated word recognition. Limitations are due to slow and low-resolution cameras or physical strain. Overall, the proposed handwriting recognition system provides an easy-to-use and accurate text input modality without placing restrictions on the users.