Evaluation of visual feedback techniques for virtual grasping with bare hands using Leap Motion and Oculus Rift
PubDate: May 2017
Teams: University of the Aegean
Writers: Spyros Vosinakis & Panayiotis Koutsabasis
Bare hand interaction (BHI) allows users to use their hands and fingers to interact with digital content without any attached devices or accessories. For BHI to realize widespread adoption, interaction techniques for fundamental operations, like grasp-and-release, need to be identified and optimized. This paper presents a controlled usability evaluation of four common visual feedback techniques in grasp-and-release tasks using bare hand interaction (BHI). The techniques are ‘object coloring,’ ‘connecting line,’ ‘shadow’ and ‘object halo.’ The usability was examined in terms of task time, accuracy, errors and user satisfaction. A software test bed was developed for two interface configurations: using the Leap Motion controller alone (desktop configuration) and using the Leap with Oculus Rift (virtual reality (VR) configuration). Participants (n 32) performed four trials × five feedback techniques × two UI (user interface) configurations, i.e., a total of 1280 trials. The results can be summarized into: (a) user performance is significantly better in the VR configuration compared to the desktop; (b) coloring techniques for visual feedback (‘object coloring’ and ‘object halo’) are more usable than ‘connecting line’ regardless of UI; (c) in the VR, coloring techniques remain more usable, while in the desktop interface the ‘shadow’ technique is also usable and preferred by users, (d) the ‘connecting line’ technique often distracts users from grasp-and-release tasks on static targets. (e) Some visual feedback is always preferred by users than none in both VR and desktop. We discuss these findings in terms of design recommendations for bare hands interactions that involve grasp-and-release tasks.