Exploring Fingers' Limitation of Texture Density Perception on Ultrasonic Haptic Displays

International audienceRecent research in haptic feedback is motivated by the crucial role that tactile perception plays in everyday touch interactions. In this paper, we describe psychophysical experiments to investigate the perceptual threshold of individual fingers on both the right and left hand of right-handed participants using active dynamic touch for spatial period discrimination of both sinusoidal and square-wave gratings on ultra-sonic haptic touchscreens. Both one-finger and multi-finger touch were studied and compared. Our results indicate that users' finger identity (index finger, middle finger, etc.) significantly affect the perception of both gratings in the case of one-finger exploration. We show that index finger and thumb are the most sensitive in all conditions whereas little finger followed by ring are the least sensitive for haptic perception. For multi-finger exploration, the right hand was found to be more sensitive than the left hand for both gratings. Our findings also demonstrate similar perception sensitivity between multi-finger exploration and the index finger of users' right hands (i.e. dominant hand in our study), while significant difference was found between single and multi-finger perception sensitivity for the left hand

Haptics: Science, Technology, Applications

This open access book constitutes the proceedings of the 12th International Conference on Human Haptic Sensing and Touch Enabled Computer Applications, EuroHaptics 2020, held in Leiden, The Netherlands, in September 2020. The 60 papers presented in this volume were carefully reviewed and selected from 111 submissions. The were organized in topical sections on haptic science, haptic technology, and haptic applications. This year's focus is on accessibility

FingerSlide: Investigating Passive Haptic Sliding As A Tacton Channel

The haptic sensation of sliding a surface under a probing finger can be used to convey surface information or coded data to the user. In this paper, we investigate users' ability to discern different sliding profiles based on the velocity and direction of sliding for use as haptic-tactons. We built FingerSlide, a novel haptic device which can position and control moving surfaces under a user's finger and used this to run two independent studies. The first study investigates if users can identify the direction of sliding at different velocities. The second study investigates if the users can distinguish a difference between two velocities. Our results show a faster response for higher velocities in the direction study and high error rates in identifying differences in the direction study. We discuss these results and infer design considerations for haptic devices that use the sliding effect to convey information

Haptics: Science, Technology, Applications

This open access book constitutes the proceedings of the 12th International Conference on Human Haptic Sensing and Touch Enabled Computer Applications, EuroHaptics 2020, held in Leiden, The Netherlands, in September 2020. The 60 papers presented in this volume were carefully reviewed and selected from 111 submissions. The were organized in topical sections on haptic science, haptic technology, and haptic applications. This year's focus is on accessibility

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

Haptics: Science, Technology, Applications

This open access book constitutes the proceedings of the 13th International Conference on Human Haptic Sensing and Touch Enabled Computer Applications, EuroHaptics 2022, held in Hamburg, Germany, in May 2022. The 36 regular papers included in this book were carefully reviewed and selected from 129 submissions. They were organized in topical sections as follows: haptic science; haptic technology; and haptic applications

Touch- and Walkable Virtual Reality to Support Blind and Visually Impaired Peoples‘ Building Exploration in the Context of Orientation and Mobility

Der Zugang zu digitalen Inhalten und Informationen wird immer wichtiger für eine erfolgreiche Teilnahme an der heutigen, zunehmend digitalisierten Zivilgesellschaft. Solche Informationen werden meist visuell präsentiert, was den Zugang für blinde und sehbehinderte Menschen einschränkt. Die grundlegendste Barriere ist oft die elementare Orientierung und Mobilität (und folglich die soziale Mobilität), einschließlich der Erlangung von Kenntnissen über unbekannte Gebäude vor deren Besuch. Um solche Barrieren zu überbrücken, sollten technische Hilfsmittel entwickelt und eingesetzt werden. Es ist ein Kompromiss zwischen technologisch niedrigschwellig zugänglichen und verbreitbaren Hilfsmitteln und interaktiv-adaptiven, aber komplexen Systemen erforderlich. Die Anpassung der Technologie der virtuellen Realität (VR) umfasst ein breites Spektrum an Entwicklungs- und Entscheidungsoptionen. Die Hauptvorteile der VR-Technologie sind die erhöhte Interaktivität, die Aktualisierbarkeit und die Möglichkeit, virtuelle Räume und Modelle als Abbilder von realen Räumen zu erkunden, ohne dass reale Gefahren und die begrenzte Verfügbarkeit von sehenden Helfern auftreten. Virtuelle Objekte und Umgebungen haben jedoch keine physische Beschaffenheit. Ziel dieser Arbeit ist es daher zu erforschen, welche VR-Interaktionsformen sinnvoll sind (d.h. ein angemessenes Verbreitungspotenzial bieten), um virtuelle Repräsentationen realer Gebäude im Kontext von Orientierung und Mobilität berührbar oder begehbar zu machen. Obwohl es bereits inhaltlich und technisch disjunkte Entwicklungen und Evaluationen zur VR-Technologie gibt, fehlt es an empirischer Evidenz. Zusätzlich bietet diese Arbeit einen Überblick über die verschiedenen Interaktionen. Nach einer Betrachtung der menschlichen Physiologie, Hilfsmittel (z.B. taktile Karten) und technologischen Eigenschaften wird der aktuelle Stand der Technik von VR vorgestellt und die Anwendung für blinde und sehbehinderte Nutzer und der Weg dorthin durch die Einführung einer neuartigen Taxonomie diskutiert. Neben der Interaktion selbst werden Merkmale des Nutzers und des Geräts, der Anwendungskontext oder die nutzerzentrierte Entwicklung bzw. Evaluation als Klassifikatoren herangezogen. Begründet und motiviert werden die folgenden Kapitel durch explorative Ansätze, d.h. im Bereich 'small scale' (mit sogenannten Datenhandschuhen) und im Bereich 'large scale' (mit einer avatargesteuerten VR-Fortbewegung). Die folgenden Kapitel führen empirische Studien mit blinden und sehbehinderten Nutzern durch und geben einen formativen Einblick, wie virtuelle Objekte in Reichweite der Hände mit haptischem Feedback erfasst werden können und wie verschiedene Arten der VR-Fortbewegung zur Erkundung virtueller Umgebungen eingesetzt werden können. Daraus werden geräteunabhängige technologische Möglichkeiten und auch Herausforderungen für weitere Verbesserungen abgeleitet. Auf der Grundlage dieser Erkenntnisse kann sich die weitere Forschung auf Aspekte wie die spezifische Gestaltung interaktiver Elemente, zeitlich und räumlich kollaborative Anwendungsszenarien und die Evaluation eines gesamten Anwendungsworkflows (d.h. Scannen der realen Umgebung und virtuelle Erkundung zu Trainingszwecken sowie die Gestaltung der gesamten Anwendung in einer langfristig barrierefreien Weise) konzentrieren.Access to digital content and information is becoming increasingly important for successful participation in today's increasingly digitized civil society. Such information is mostly presented visually, which restricts access for blind and visually impaired people. The most fundamental barrier is often basic orientation and mobility (and consequently, social mobility), including gaining knowledge about unknown buildings before visiting them. To bridge such barriers, technological aids should be developed and deployed. A trade-off is needed between technologically low-threshold accessible and disseminable aids and interactive-adaptive but complex systems. The adaptation of virtual reality (VR) technology spans a wide range of development and decision options. The main benefits of VR technology are increased interactivity, updatability, and the possibility to explore virtual spaces as proxies of real ones without real-world hazards and the limited availability of sighted assistants. However, virtual objects and environments have no physicality. Therefore, this thesis aims to research which VR interaction forms are reasonable (i.e., offering a reasonable dissemination potential) to make virtual representations of real buildings touchable or walkable in the context of orientation and mobility. Although there are already content and technology disjunctive developments and evaluations on VR technology, there is a lack of empirical evidence. Additionally, this thesis provides a survey between different interactions. Having considered the human physiology, assistive media (e.g., tactile maps), and technological characteristics, the current state of the art of VR is introduced, and the application for blind and visually impaired users and the way to get there is discussed by introducing a novel taxonomy. In addition to the interaction itself, characteristics of the user and the device, the application context, or the user-centered development respectively evaluation are used as classifiers. Thus, the following chapters are justified and motivated by explorative approaches, i.e., in the group of 'small scale' (using so-called data gloves) and in the scale of 'large scale' (using an avatar-controlled VR locomotion) approaches. The following chapters conduct empirical studies with blind and visually impaired users and give formative insight into how virtual objects within hands' reach can be grasped using haptic feedback and how different kinds of VR locomotion implementation can be applied to explore virtual environments. Thus, device-independent technological possibilities and also challenges for further improvements are derived. On the basis of this knowledge, subsequent research can be focused on aspects such as the specific design of interactive elements, temporally and spatially collaborative application scenarios, and the evaluation of an entire application workflow (i.e., scanning the real environment and exploring it virtually for training purposes, as well as designing the entire application in a long-term accessible manner)

Designing Haptic Clues for Touchscreen Kiosks

Most interactive touchscreen kiosks are a challenge to accessibility: if graphics and sound fail in communication, the interaction process halts. In such a case, turning to the only remaining environmentally suited sense - the touch - is an intuitive option. To reinforce the interaction with interactive touchscreen kiosks it is possible to add haptic (touchable) feedback into the features of the device. The range of touchscreen-suited haptic technologies already enables some touch feedback from touchscreen surfaces and significant leaps still forward are being made at a constant rate. Due to this development it is relevant to review the human-centred factors affecting the design of haptic touchscreen in public kiosks. This thesis offers an overview for designing haptic clues for touchscreen kiosks. It emphasizes context sensitivity and the meaningfulness and communicability of different haptic design variants. As the main contribution, this thesis collects together the important considerations for the conscious design of haptic features in interactive kiosks and offers points of multimodal design considerations for designers intending to enrich their touchscreen interaction with haptic features