Wearable haptic displays that relocate feedback away from the fingertip provide a much-needed sense of touch to interactions in virtual reality, while also leaving the fingertip free from occlusion for augmented reality tasks. However, the impact of relocation on perceptual sensitivity to dynamic changes in actuation during active movement remains unclear. In this work, we investigate the perceived realism of virtual textures rendered via vibrations relocated to the base of the index finger and compare three different methods of modulating vibrations with active finger speed. For the first two methods, changing finger speed induced proportional changes in either frequency or amplitude of vibration, and for the third method did not modulate vibration. In psychophysical experiments, participants compared different types of modulation to each other, as well as to real 3D-printed textured surfaces. Results suggest that frequency modulation results in more realistic sensations for coarser textures, whereas participants were less discerning of modulation type for finer textures. Additionally, we presented virtual textures either fully virtually in midair or under augmented reality in which the finger contacted a flat surface; while we found no difference in experimental performance, participants were divided by a strong preference for either the contact or non-contact condition.

Wearable tactile displays can create the illusion of touching real textures by applying vibrations to the finger as it moves across a virtual surface. There are many possible methods of modulating this vibratory content with finger movement, each potentially best suited to different texture length scales. Using a vibrotactile haptic ring paired with finger position tracking, here we explore the advantages of three vibration modulation schemes that scale the frequency or amplitude of applied vibrations as a function of finger velocity. Ongoing psychophysical experiments will characterize trade-offs between ease of control and perceived texture realism for frequencies associated with both coarse and fine textures.