Hand-to-hand: an intermanual illusion of movement

Apparent tactile motion has been shown to occur across many contiguous parts of the body, such as fingers, forearms, and back. A recent study demonstrated the possibility of eliciting the illusion of movement from one hand to the other when interconnected by a tablet. In this paper, we explore intermanual apparent tactile motion without any object between them. In a series of psychophysical experiments, we determine the control space for generating smooth and consistent motion, using two vibrating handles which we refer to as the Hand-to-Hand vibrotactile device. In a first experiment, we investigated the occurrence of the phenomenon (i.e., movement illusion) and the generation of a perceptive model. In a second experiment, based on those results, we investigated the effect of hand postures on the illusion. Finally, in a third experiment, we explored two visuo-tactile matching tasks in a multimodal VR setting. Our results can be applied in VR applications with intermanual tactile interactions

Touching is believing: creating illusions and feeling of embodiment with mid-air haptic technology

Over the last two decades, the sense of touch has received new attention from the scientific community.Several haptic devices have been developed to address the complexity of the sense of touch, the latest addition being mid-air (contactless) haptic technology. An interesting series of previous research has suggested an easier way to tackle the complexity of designing convincing tactile sensations by exploiting tactile illusions. Tactile illusions rely on perceptual shortcuts based on the psychophysics of the tactile receptors. Currently, studies exploring the perceptual space of mid-air haptics and its applicability in the tactile illusions field are still limited in number. This thesis aims to contribute to the field of Human-Computer Interaction (HCI) by investigating the perceptual design space of ultrasonic mid-air haptics technology. Specifically, in a first set of three studies, we investigate the absolute thresholds (minimal amount of a property of astimulus that a user can detect) for control points (CP) at different frequencies on the hand and arm (Study 1). Then we investigate the optimal sampling rate needed to drive the device in an optimal fashion and its relationship with shape size (Study 2). Next, we apply a new technique to increase users’ performance in a shape discrimination task (Study 3). In Study 4, we start the exploration of a tactile illusion of movement using contact touch and later, we apply a similar procedure to investigate the feasibility of creating a tactile illusion of movement between the two non-interconnected hands by using mid-air touch (Study 5). Finally, in Study 6, we explore our sense of touch in VR, while providing an illusion of rain drops through mid-air haptics, to recreate a virtual hand illusion (VHI) to explore the boundaries of our sense of embodiment. Therefore, the contribution of this work is threefold: a) we contribute by adding new knowledge on the psychophysical space for mid-air haptics, b) we test the potential to create realistic tactile sensations by exploiting tactile illusions with mid-air haptic technology, and c) we demonstrate how tactile illusions mediated by mid-air haptics can convey a sense of embodiment in VR environments

Creating an illusion of movement between the hands using mid-air touch

Apparent tactile motion (ATM) has been shown to occur across many contiguous parts of the body, such as fingers, forearms and the back. More recently, the illusion has also been elicited on non-contiguous part of the body, such as from one hand to the other when interconnected or not interconnected by an object in between the hands. Here we explore the reproducibility of the intermanual tactile illusion of movement between two free hands by employing mid-air tactile stimulation. We investigate the optimal parameters to generate a continuous and smooth motion using two arrays of ultrasound speakers, and two stimulation techniques (i.e. static vs. dynamic focal point). In the first experiment, we investigate the occurrence of the illusion when using a static focal point, and we define a perceptive model. In the second experiment, we examine the illusion using a dynamic focal point, defining a second perceptive model. Finally, we discuss the differences between the two techniques

Multimodality in VR: A survey

Virtual reality (VR) is rapidly growing, with the potential to change the way we create and consume content. In VR, users integrate multimodal sensory information they receive, to create a unified perception of the virtual world. In this survey, we review the body of work addressing multimodality in VR, and its role and benefits in user experience, together with different applications that leverage multimodality in many disciplines. These works thus encompass several fields of research, and demonstrate that multimodality plays a fundamental role in VR; enhancing the experience, improving overall performance, and yielding unprecedented abilities in skill and knowledge transfer

Audio-tactile stimuli to improve health and well-being : a preliminary position paper

From literature and through common experience it is known that stimulation of the tactile (touch) sense or auditory (hearing) sense can be used to improve people's health and well-being. For example, to make people relax, feel better, sleep better or feel comforted. In this position paper we propose the concept of combined auditory-tactile stimulation and argue that it potentially has positive effects on human health and well-being through influencing a user's body and mental state. Such effects have, to date, not yet been fully explored in scientific research. The current relevant state of the art is briefly addressed and its limitations are indicated. Based on this, a vision is presented of how auditory-tactile stimulation could be used in healthcare and various other application domains. Three interesting research challenges in this field are identified: 1) identifying relevant mechanisms of human perception of combined auditory-tactile stimuli; 2) finding methods for automatic conversions between audio and tactile content; 3) using measurement and analysis of human bio-signals and behavior to adapt the stimulation in an optimal way to the user. Ideas and possible routes to address these challenges are presented

Multimodality in {VR}: {A} Survey

Virtual reality has the potential to change the way we create and consume content in our everyday life. Entertainment, training, design and manufacturing, communication, or advertising are all applications that already benefit from this new medium reaching consumer level. VR is inherently different from traditional media: it offers a more immersive experience, and has the ability to elicit a sense of presence through the place and plausibility illusions. It also gives the user unprecedented capabilities to explore their environment, in contrast with traditional media. In VR, like in the real world, users integrate the multimodal sensory information they receive to create a unified perception of the virtual world. Therefore, the sensory cues that are available in a virtual environment can be leveraged to enhance the final experience. This may include increasing realism, or the sense of presence; predicting or guiding the attention of the user through the experience; or increasing their performance if the experience involves the completion of certain tasks. In this state-of-the-art report, we survey the body of work addressing multimodality in virtual reality, its role and benefits in the final user experience. The works here reviewed thus encompass several fields of research, including computer graphics, human computer interaction, or psychology and perception. Additionally, we give an overview of different applications that leverage multimodal input in areas such as medicine, training and education, or entertainment; we include works in which the integration of multiple sensory information yields significant improvements, demonstrating how multimodality can play a fundamental role in the way VR systems are designed, and VR experiences created and consumed