Effect of the predictive keyboard with magnification and protrusion on the bare-hand input in virtual reality

Bare-hand input, advantaged as the natural interaction, is a promising way of text input in VR. The paper proposes the predictive next-letter highlighting technology and investigates its spatial enhancement (magnification, protrusion) of the 100% correct predicted keys on bare-hand input in virtual reality. In Experiment One, the predicted keys are magnified in three levels (no magnification, medium magnification, maximum magnification). Results show that magnification can improve input performance, but excessive magnification may decrease participants’ willingness to use it. In Experiment Two, the predicted keys are protruded in four levels (0 mm, 3 mm, 6 mm, 9 mm). We found that the overall input performance, especially on intrusion errors, is impaired with protrusion distance. The level of agility may be the critical factor affecting the effect of protrusion distance. In conclusion, the study found that the predicted keys with magnification are good choices for VR bare-hand inputting, especially for the low-agile person. However, the influence of protrusion distance on bare-hand input performance may vary from person to person.