Efficient dynamic time warping for 3D handwriting recognition using gyroscope equipped smartphones

• This is the first smartphone demonstration study for 3D handwriting recognition.
• A 3D gyroscope is superior to 3D accelerometers to recognize similar shaped letters.
• A fast DTW reduced the computing cost of the recognition algorithm in mobile devices.

Handwriting character recognition from three-dimensional (3D) accelerometer data has emerged as a popular technique for natural human computer interaction. In this paper, we propose a 3D gyroscope-based handwriting recognition system that uses stepwise lower-bounded dynamic time warping, instead of conventional 3D accelerometer data. The results of experiments conducted indicate that our proposed method is more effective and efficient than conventional methods for user-independent recognition of the 26 lowercase letters in the English alphabet.