Mobile accessibility: natural user interface for motion-impaired users
We designed a natural user interface to access mobile devices for motion-impaired people who cannot use the standard multi-touch input system to work with tablets and smartphones. We detect the head motion of the user by means of the frontal camera and use its position to interact with the mobile device. The purpose of this work is to evaluate the performance of the system. We conducted two laboratory studies with 12 participants without disabilities and a field study with four participants with multiple sclerosis (MS). The first laboratory study was done to test the robustness and to count with a base to compare the results of the evaluation done with the participants with MS. Once observed the results of the participants with disabilities, we conducted a new laboratory study with participants without disabilities simulating the limitations of the users with MS to tune the system. All participants completed a set of defined tasks: pointing and pointing-selecting. We logged use and conducted questionnaires post-experiment. Our results showed positive outcomes using the system as an input device, although apps should follow a set of recommendations on the size of the targets and their position to facilitate the interaction with mobile devices for motion-impaired users. The work demonstrates the interface’s possibilities for mobile accessibility for motion-impaired users who need alternative access devices to interact with mobile devices.