ACCESSIBLE TOOLS ON TOUCHSCREEN DEVICES FOR BLIND AND VISUALLY IMPAIRED PEOPLE
Input methods on touchscreen devices are often developed without taking into account the needs of people with no or low vision. Because of this, there has been a strong research interest in the development of techniques for touchscreen accessibility for blind people, such as integrating the screen reader in smartphone devices. However, the QWERTY keyboard and the button calculator with VoiceOver and many other proposed touchscreen keyboards are in many ways inaccessible to blind and visually impaired people because they primarily require finding key locations on a touchscreen and both hands are needed to interact with keyboard interfaces. The primary objective of this research is to create, design and evaluate button-free user interfaces that allow blind users to overcome the limitations of button-based input methods, as well as mitigate privacy and security concerns. This research presents a model of designing accessible button-free input methods on smartphone devices that assist blind and visually impaired users. This thesis outlines the progressive development and evaluation of button-free user interfaces designed to make touchscreen devices on mobile phones more accessible for blind and visually impaired individuals. The first of these, SingleTapBraille, makes inputting text faster and more accurate than with the most common standard option, QWERTY keyboard with VoiceOver. Similarly, BrailleTap makes the entry of numbers and arithmetic symbols easier than with the standard smartphone calculator. We also introduce BrailleEnter, which further improves the functionality of SingleTapBraille and BrailleTap. Lastly, we address the security concerns associated with systems that increase accessibility for visually impaired individuals, specifically the password vulnerability associated with the auditory feedback provided by the VoiceOver service. We address this with BraillePassword, which provides input feedback to the user via haptic feedback that only the user can access. Four user studies are conducted with blind and visually impaired people. Data is generated through qualitative and quantitative methods. Findings indicate that the developed Braille tools significantly enhance accessibility, and has the potential to be valuable to blind users. The proposed model allows users to overcome outstanding accessibility challenges as well as mitigate privacy and security risks they face when interacting with smartphone devices.