Adding Touch to Immersive Media: An Overview of the MPEG Haptics Coding Standard.

In May 2021, MPEG issued a call for proposals for the specification of a new coding format for haptic data. Following this call, a baseline reference design and associated software implementation were defined for the representation and coding of haptic data. It resulted in a standard that defines a complete generic framework for the delivery of haptic signals, allowing the development of current and future haptic applications in the mobile, gaming, and virtual reality domains.

Tactile sensitivity to missing tones in complex vibrotactile signals.

Haptic interactions with objects induce complex vibrotactile signals that are central to tactile perception. Despite the broad literature on vibrotactile perception, surprisingly little is known about the sensory processing of complex tactile signals made of multiple pure tones. To fill this gap, the study reported here investigated the impact of the constitutive pure tones of a complex vibrotactile signal on its perception.

Investigating the Haptic Perception of Directional Information Within a Handle.

This paper studies the perception of 2-dimensional directional cues presented on a hand-held tangible interface that resembles a cylindrical handle. The tangible interface is designed to be comfortably held with one hand and houses five custom electromagnetic actuators composed of coils as stators and magnets as movers. We carried out a human subjects experiment enrolling 24 participants, analysing the recognition rate of directional cues using the actuators either to vibrate or tap in sequence across the user's palm.

Normal and tangential forces combine to convey contact pressure during dynamic tactile stimulation.

Humans need to accurately process the contact forces that arise as they perform everyday haptic interactions such as sliding the fingers along a surface to feel for bumps, sticky regions, or other irregularities. Several different mechanisms are possible for how the forces on the skin could be represented and integrated in such interactions. In this study, we used a force-controlled robotic platform and simultaneous ultrasonic modulation of the finger-surface friction to independently manipulate the normal and tangential forces during passive haptic stimulation by a flat surface.

Phononic Crystals Applied to Localised Surface Haptics.

Metamaterials are solid lattices with periodicities commensurate with desired wavelengths. Their geometric features can endow the bulk material with unusual properties, such as inter alia, negative indices of refraction or unique absorbing qualities. Mesoscale metamaterials and phononic crystals can be designed to cause the occurence of band gaps in the ultrasonic domain.

Physical Variables Underlying Tactile Stickiness During Fingerpad Detachment.

One may notice a relatively wide range of tactile sensations even when touching the same hard, flat surface in similar ways. Little is known about the reasons for this variability, so we decided to investigate how the perceptual intensity of light stickiness relates to the physical interaction between the skin and the surface. We conducted a psychophysical experiment in which nine participants actively pressed their finger on a flat glass plate with a normal force close to 1.

Compensating for Fingertip Size to Render Tactile Cues More Accurately.

Fingertip haptic feedback offers advantages in many applications, including robotic teleoperation, gaming, and training. However, fingertip size and shape vary significantly across humans, making it difficult to design fingertip interfaces and rendering techniques suitable for everyone. This article starts with an existing data-driven haptic rendering algorithm that ignores fingertip size, and it then develops two software-based approaches to personalize this algorithm for fingertips of different sizes using either additional data or geometry.

The Perception of Ultrasonic Square Reductions of Friction With Variable Sharpness and Duration.

The human perception of square ultrasonic modulation of the finger-surface friction was investigated during active tactile exploration by using short frictional cues of varying duration and sharpness. In a first experiment, we asked participants to discriminate the transition time and duration of short square ultrasonic reductions of friction. They proved very sensitive to discriminate millisecond differences in these two parameters with the average psychophysical thresholds being 2.

The tactile perception of transient changes in friction.

When we touch an object or explore a texture, frictional strains are induced by the tactile interactions with the surface of the object. Little is known about how these interactions are perceived, although it becomes crucial for the nascent industry of interactive displays with haptic feedback (e.g.

Touch uses frictional cues to discriminate flat materials.

In a forced-choice task, we asked human participants to discriminate by touch alone glass plates from transparent polymethyl methacrylate (PMMA) plastic plates. While the surfaces were flat and did not exhibit geometric features beyond a few tens of nanometres, the materials differed by their molecular structures. They produced similar coefficients of friction and thermal effects were controlled.

Expectation and attention in hierarchical auditory prediction.

Hierarchical predictive coding suggests that attention in humans emerges from increased precision in probabilistic inference, whereas expectation biases attention in favor of contextually anticipated stimuli. We test these notions within auditory perception by independently manipulating top-down expectation and attentional precision alongside bottom-up stimulus predictability. Our findings support an integrative interpretation of commonly observed electrophysiological signatures of neurodynamics, namely mismatch negativity (MMN), P300, and contingent negative variation (CNV), as manifestations along successive levels of predictive complexity.