PinchText: One-Handed Text Entry Technique Combining Pinch Gestures and Hand Positions for Head-Mounted Displays

This paper presents PinchText, a mid-air technique with a condensed keys-based keyboard, which combines hand positions and pinch gestures, enabling one-handed text entry for Head-mounted displays (HMDs). Firstly, we conduct Study 1 to collect and analyze the typing data of PinchText with two arm postures and two movement directions, obtaining the range of hand position corresponding to the middle key set. Then, we conduct Study 2, a 6-block experiment, finding that PinchText with Hand-Up Vertical (UpV) and Hand-Down Vertical (DownV) modes could achieve a speed of 12.71 words-per-minute (WPM) and 11.14 WPM respectively with both uncorrected error rates less than 0.5%, which is 71% faster than the index finger pinch-based technique. Finally, Study 3 is conducted to explore the potential of reducing the size of the decoupled visual keyboard of PinchText, verifying that the occlusion of the virtual keyboard can be decreased. Overall, PinchText is an efficient, easy-to-learn, and comfortable text entry technique for HMDs.