A Study Of Text Entry Methods For The Blind And Eyes-Free Operations On Multi-Touch Devices

With the development of computer technology,more and more touch-based screens with various sizes have been used under different scenarios.There exist many text entry methods for small-sized touch-based screens,such as those of smart mobile phones and watches,whereas few methods for large-sized multi-touch screens.As we know,we employ a certain finger to entry certain characters with a physical keyboard.Inspired by this,we proposed a method of mapping characters to fingers,certain characters being ‘bound' to each a corresponding finger.And then our fingers are no longer restricted by fixed space on a multi-touch screen,and can be positioned comfortably on any region.Additionally,this method supports eyes-free text entry on a multi-touch screen and can serve the blind.Three experiments were conducted to assess the usability of the method for both those with normal vision and the blind.A recognition algorithm was proposed to identify ten fingers resting on a screen.The analytic results of the first quantitative experiment display correct finger-identification rate reached 99.3%.In the second experiment,we proposed 4 text entry gestures supporting eyes-free operations,i.e.,Tap,Flick,Swipe,and Swipe with Thumbs Free.We proposed 4 text entry techniques by ‘binding' characters to fingers according to the standard method when we typing with a physical QWERTY keyboard,and inputting text with the 4 gestures.The 4 entry techniques were compared with a standard soft keyboard in the experiment in both a visible interface and an invisible one.The experimental results reveal that the 4 proposed techniques outperformed the soft keyboard in terms of both speed and accuracy in invisible condition.Based on the results of the second experiment,we enhanced and optimized some of the prementioned text entry gestures,and proposed Tapping,Swiping,and Flicking gestures.The 3 gestures were combined with 2 keyboard layouts,i.e.,Alphabetical and QWERTY,we then got 6 text entry techniques.A quantitative experiment was conducted to compare the 6 techniques with the standard entry technique,Talkback,attended by 14 blind participants.The analytic results of the third experiment display that the 6 proposed methods outperformed the baseline on speed,the QWERTY layout defeated the Alphabetical,and Flicking performed the best in terms of both speed and accuracy among the three text entry gestures.