User experience to improve the usability of a vision-based interface

When we develop an input device for users to communicate with computers, we have to take into account that end-users must consider the utilization of the device to be effective, efficient and satisfactory. Users whose expectations are unmet by the interface will tend to abandon it. In this paper we present a vision-based interface for motor-impaired users; a multidisciplinary group developed this interface. The user’s preferences are a critical issue when selecting an access device; therefore, user requirements should be included in the design. Usability evaluation should be integrated into relevant phases of software development. In order to evaluate the design, we present a process with multiple user studies at different development stages. We describe the combination of a development project and its implementation, with user experience considerations embedded in the process. Finally, we studied the performance of the interface through several tests, paying special attention to satisfaction and fatigue. From our results we observed that although several users found the interface tiring, their satisfaction level was encouraging, suggesting the interface is usable.

Research highlights
► Users experience affected the design and development of a hands-free interface based on computer vision techniques.
► Principles for implementing vision-based interfaces for disabled users are recommended.
► The hands-free interface helped the users to improve their accessibility, to gain head control and to work with better body posture.
► The hands-free interface can be used as a rehabilitation tool.