Seeing Is Believing but Feeling Is the Truth: Visualising Mid-Air Haptics in Oil Baths and Lightboxes

Abstract

Ultrasound is beyond the range of human hearing and tactile perception. In the past few years, several modulation techniques have been invented to overcome this and evoke perceptible tactile sensations of shapes and textures that can be felt, but not seen. Therefore, mid-air haptic technology has found use in several human computer interaction applications and is the focus of multiple research efforts. Visualising the induced acoustic pressure field can help understand and optimise how different modulation techniques translate into tactile sensations. Here, rather than using acoustic simulation tools to do that, we exploit the micro-displacement of a thin layer of oil to visualize the impinging acoustic pressure field outputted from an ultrasonic phased array device. Our demo uses a light source to illuminate the oil displacement and project it onto a screen to produce an interactive lightbox display. Interaction is facilitated via optical hand-tracking technology thus enabling an instantaneous and aesthetically pleasing visualisation of mid-air haptics.