Finger Based Technique (FBT): An Innovative System for Improved Usability for the Blind Users' Dynamic Interaction with Mobile Touch Screen Devices

This paper presents Finger Based Technique (FBT) prototypes, a novel interaction system for blind users, which is especially designed and developed for non-visual touch screen devices and their applications. The FBT prototypes were developed with virtual keys to be identified based on finger holding positions. Two different models namely the single digit FBT and double digit FBT were propounded. FBT technique were applied using two different phone dialer applications: a single digit virtual key for the single digit FBT model and a double digit virtual key with audio feedback enabling touch as input gesture for the later one. An evaluation with 7 blind participants showed that single digit FBT was significantly faster and more accurate than double digit FBT. In addition to that, single digit FBT was found to be much faster than iPhone VoiceOver entry speeds in performing similar tasks. Furthermore, our research also suggests 11 accessible regions for quick access or navigation in flat touch screen based smart phones for blind users. These accessible regions will serve as a usability design framework and facilitate the developers to place the widget for the blind user for dynamic interaction with the touch screen devices. As far as is known to the authors, this is a novel suggestion.