FingerX: Rendering Haptic Shapes of Virtual Objects Augmented by Real Objects using Extendable and Withdrawable Supports on Fingers

Interacting with not only virtual but also real objects, or even virtual objects augmented by real objects becomes a trend of virtual reality (VR) interactions and is common in augmented reality (AR). However, current haptic shape rendering devices generally focus on feedback of virtual objects, and require the users to put down or take off those devices to perceive real objects. Therefore, we propose FingerX to render haptic shapes and enable users to touch, grasp and interact with virtual and real objects simultaneously. An extender on the fingertip extends to a corresponding height to support between the fingertip and the real objects or the hand, to render virtual shapes. A ring rotates and withdraws the extender behind the fingertip when touching real objects. By independently controlling four extenders and rings on each finger with the exception of the pinky finger, FingerX renders feedback in three common scenarios, including touching virtual objects augmented by real environments (e.g., a desk), grasping virtual objects augmented by real objects (e.g., a bottle) and grasping virtual objects in the hand. We conducted a shape recognition study to evaluate the recognition rates for these three scenarios and obtained an average recognition rate of 76.59% with shape visual feedback. We then performed a VR study to observe how users interact with virtual and real objects simultaneously and verify that FingerX significantly enhances VR realism, compared to current vibrotactile methods.