HapticHead - Augmenting Reality via Tactile Cues

Information overload is increasingly becoming a challenge in today's world. Humans have only a limited amount of attention to allocate between sensory channels and tend to miss or misjudge critical sensory information when multiple activities are going on at the same time. For example, people may miss the sound of an approaching car when walking across the street while looking at their smartphones. Some sensory channels may also be impaired due to congenital or acquired conditions. Among sensory channels, touch is often experienced as obtrusive, especially when it occurs unexpectedly. Since tactile actuators can simulate touch, targeted tactile stimuli can provide users of virtual reality and augmented reality environments with important information for navigation, guidance, alerts, and notifications. In this dissertation, a tactile user interface around the head is presented to relieve or replace a potentially impaired visual channel, called \emph{HapticHead}. It is a high-resolution, omnidirectional, vibrotactile display that presents general, 3D directional, and distance information through dynamic tactile patterns. The head is well suited for tactile feedback because it is sensitive to mechanical stimuli and provides a large spherical surface area that enables the display of precise 3D information and allows the user to intuitively rotate the head in the direction of a stimulus based on natural mapping. Basic research on tactile perception on the head and studies on various use cases of head-based tactile feedback are presented in this thesis. Several investigations and user studies have been conducted on (a) the funneling illusion and localization accuracy of tactile stimuli around the head, (b) the ability of people to discriminate between different tactile patterns on the head, (c) approaches to designing tactile patterns for complex arrays of actuators, (d) increasing the immersion and presence level of virtual reality applications, and (e) assisting people with visual impairments in guidance and micro-navigation. In summary, tactile feedback around the head was found to be highly valuable as an additional information channel in various application scenarios. Most notable is the navigation of visually impaired individuals through a micro-navigation obstacle course, which is an order of magnitude more accurate than the previous state-of-the-art, which used a tactile belt as a feedback modality. The HapticHead tactile user interface's ability to safely navigate people with visual impairments around obstacles and on stairs with a mean deviation from the optimal path of less than 6~cm may ultimately improve the quality of life for many people with visual impairments.Die Informationsüberlastung wird in der heutigen Welt zunehmend zu einer Herausforderung. Der Mensch hat nur eine begrenzte Menge an Aufmerksamkeit, die er zwischen den Sinneskanälen aufteilen kann, und neigt dazu, kritische Sinnesinformationen zu verpassen oder falsch einzuschätzen, wenn mehrere Aktivitäten gleichzeitig ablaufen. Zum Beispiel können Menschen das Geräusch eines herannahenden Autos überhören, wenn sie über die Straße gehen und dabei auf ihr Smartphone schauen. Einige Sinneskanäle können auch aufgrund von angeborenen oder erworbenen Erkrankungen beeinträchtigt sein. Unter den Sinneskanälen wird Berührung oft als aufdringlich empfunden, besonders wenn sie unerwartet auftritt. Da taktile Aktoren Berührungen simulieren können, können gezielte taktile Reize den Benutzern von Virtual- und Augmented Reality Anwendungen wichtige Informationen für die Navigation, Führung, Warnungen und Benachrichtigungen liefern. In dieser Dissertation wird eine taktile Benutzeroberfläche um den Kopf herum präsentiert, um einen möglicherweise beeinträchtigten visuellen Kanal zu entlasten oder zu ersetzen, genannt \emph{HapticHead}. Es handelt sich um ein hochauflösendes, omnidirektionales, vibrotaktiles Display, das allgemeine, 3D-Richtungs- und Entfernungsinformationen durch dynamische taktile Muster darstellt. Der Kopf eignet sich gut für taktiles Feedback, da er empfindlich auf mechanische Reize reagiert und eine große sphärische Oberfläche bietet, die die Darstellung präziser 3D-Informationen ermöglicht und es dem Benutzer erlaubt, den Kopf aufgrund der natürlichen Zuordnung intuitiv in die Richtung eines Reizes zu drehen. Grundlagenforschung zur taktilen Wahrnehmung am Kopf und Studien zu verschiedenen Anwendungsfällen von kopfbasiertem taktilem Feedback werden in dieser Arbeit vorgestellt. Mehrere Untersuchungen und Nutzerstudien wurden durchgeführt zu (a) der Funneling Illusion und der Lokalisierungsgenauigkeit von taktilen Reizen am Kopf, (b) der Fähigkeit von Menschen, zwischen verschiedenen taktilen Mustern am Kopf zu unterscheiden, (c) Ansätzen zur Gestaltung taktiler Muster für komplexe Arrays von Aktoren, (d) der Erhöhung des Immersions- und Präsenzgrades von Virtual-Reality-Anwendungen und (e) der Unterstützung von Menschen mit Sehbehinderungen bei der Führung und Mikronavigation. Zusammenfassend wurde festgestellt, dass taktiles Feedback um den Kopf herum als zusätzlicher Informationskanal in verschiedenen Anwendungsszenarien sehr wertvoll ist. Am interessantesten ist die Navigation von sehbehinderten Personen durch einen Mikronavigations-Hindernisparcours, welche um eine Größenordnung präziser ist als der bisherige Stand der Technik, der einen taktilen Gürtel als Feedback-Modalität verwendete. Die Fähigkeit der taktilen Benutzerschnittstelle HapticHead, Menschen mit Sehbehinderungen mit einer mittleren Abweichung vom optimalen Pfad von weniger als 6~cm sicher um Hindernisse und auf Treppen zu navigieren, kann letztendlich die Lebensqualität vieler Menschen mit Sehbehinderungen verbessern

Spatial guiding through haptic cues in omnidirectional video

Omnidirectional video’s extensive amount of visual information challenges the users to find and stay focused on the essential parts of the video. I examined how user experience was affected when haptic cues in the head area are used to guide the viewer’s gaze towards the essential parts of omnidirectional video. User experiences with different omnidirectional video types combined with haptic guiding were compared and analyzed. Other part of the research was aimed to find out how haptic and auditory modalities and their combination affected the user experience. The participants used an Oculus Rift headset to watch omnidirectional video material and two actuators were placed on their forehead to indicate if the essential part located in the left or right direction. The results of the questionnaires and the comments showed that haptic guiding was useful and effective, though it was not experienced as a necessary feature during easy to follow and slow-paced videos. The combination of haptic guiding and audio was rated the most positive use of modalities. This feature has a lot of potential to enhance user experience of omnidirectional videos. Further studies on the long-term usage of the feature are required to eliminate the novelty effect and gain a more accurate understanding of the users’ needs

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

Designing for Mixed Reality Urban Exploration

This paper introduces a design framework for mixed reality urban exploration (MRUE), based on a concrete implementation in a historical city. The framework integrates different modalities, such as virtual reality (VR), augmented reality (AR), and haptics-audio interfaces, as well as advanced features such as personalized recommendations, social exploration, and itinerary management. It permits to address a number of concerns regarding information overload, safety, and quality of the experience, which are not sufficiently tackled in traditional non-integrated approaches. This study presents an integrated mobile platform built on top of this framework and reflects on the lessons learned.Peer reviewe

Head-mounted Sensory Augmentation System for Navigation in Low Visibility Environments

Sensory augmentation can be used to assist in some tasks where sensory information is limited or sparse. This thesis focuses on the design and investigation of a head-mounted vibrotactile sensory augmentation interface to assist navigation in low visibility environments such as firefighters’ navigation or travel aids for visually impaired people. A novel head-mounted vibrotactile interface comprising a 1-by-7 vibrotactile display worn on the forehead is developed. A series of psychophysical studies is carried out with this display to (1) determine the vibrotactile absolute threshold, (2) investigate the accuracy of vibrotactile localization, and (3) evaluate the funneling illusion and apparent motion as sensory phenomena that could be used to communicate navigation signals. The results of these studies provide guidelines for the design of head-mounted interfaces. A 2nd generation head-mounted sensory augmentation interface called the Mark-II Tactile Helmet is developed for the application of firefighters’ navigation. It consists of a ring of ultrasound sensors mounted to the outside of a helmet, a microcontroller, two batteries and a refined vibrotactile display composed of seven vibration motors based on the results of the aforementioned psychophysical studies. A ‘tactile language’, that is, a set of distinguishable vibrotactile patterns, is developed for communicating navigation commands to the Mark-II Tactile Helmet. Four possible combinations of two command presentation modes (continuous, discrete) and two command types (recurring, single) are evaluated for their effectiveness in guiding users along a virtual wall in a structured environment. Continuous and discrete presentation modes use spatiotemporal patterns that induce the experience of apparent movement and discrete movement on the forehead, respectively. The recurring command type presents the tactile command repeatedly with an interval between patterns of 500 ms while the single command type presents the tactile command just once when there is a change in the command. The effectiveness of this tactile language is evaluated according to the objective measures of the users’ walking speed and the smoothness of their trajectory parallel to the virtual wall and subjective measures of utility and comfort employing Likert-type rating scales. The Recurring Continuous (RC) commands that exploit the phenomena of apparent motion are most effective in generating efficient routes and fast travel, and are most preferred. Finally, the optimal tactile language (RC) is compared with audio guidance using verbal instructions to investigate effectiveness in delivering navigation commands. The results show that haptic guidance leads to better performance as well as lower cognitive workload compared to auditory feedback. This research demonstrates that a head-mounted sensory augmentation interface can enhance spatial awareness in low visibility environments and could help firefighters’ navigation by providing them with supplementary sensory information

Designing for Mixed Reality Urban Exploration

This paper introduces a design framework for mixed reality urban exploration (MRUE), based on a concrete implementation in a historical city. The framework integrates different modalities, such as virtual reality (VR), augmented reality (AR), and haptics-audio interfaces, as well as advanced features such as personalized recommendations, social exploration, and itinerary management. It permits to address a number of concerns regarding information overload, safety, and quality of the experience, which are not sufficiently tackled in traditional non-integrated approaches. This study presents an integrated mobile platform built on top of this framework and reflects on the lessons learned

Obstacle detection display for visually impaired:Coding of direction, distance, and height on a vibrotactile waist band

Electronic travel aids (ETAs) can potentially increase the safety and comfort of blind users by detecting and displaying obstacles outside the range of the white cane. In a series of experiments, we aim to balance the amount of information displayed and the comprehensibility of the information taking into account the risk of information overload. In Experiment 1, we investigate perception of compound signals displayed on a tactile vest while walking. The results confirm that the threat of information overload is clear and present. Tactile coding parameters that are sufficiently discriminable in isolation may not be so in compound signals and while walking and using the white cane. Horizontal tactor location is a strong coding parameter, and temporal pattern is the preferred secondary coding parameter. Vertical location is also possible as coding parameter but it requires additional tactors and makes the display hardware more complex and expensive and less user friendly. In Experiment 2, we investigate how we can off-load the tactile modality by mitigating part of the information to an auditory display. Off-loading the tactile modality through auditory presentation is possible, but this off-loading is limited and may result in a new threat of auditory overload. In addition, taxing the auditory channel may in turn interfere with other auditory cues from the environment. In Experiment 3, we off-load the tactile sense by reducing the amount of displayed information using several filter rules. The resulting design was evaluated in Experiment 4 with visually impaired users. Although they acknowledge the potential of the display, the added of the ETA as a whole also depends on its sensor and object recognition capabilities. We recommend to use not more than two coding parameters in a tactile compound message and apply filter rules to reduce the amount of obstacles to be displayed in an obstacle avoidance ETA.</p

Safe Local Navigation for Visually Impaired Users With a Time-of-Flight and Haptic Feedback Device

This paper presents ALVU (Array of Lidars and Vibrotactile Units), a contactless, intuitive, hands-free, and discreet wearable device that allows visually impaired users to detect low- and high-hanging obstacles, as well as physical boundaries in their immediate environment. The solution allows for safe local navigation in both confined and open spaces by enabling the user to distinguish free space from obstacles. The device presented is composed of two parts: a sensor belt and a haptic strap. The sensor belt is an array of time-of-flight distance sensors worn around the front of a user's waist, and the pulses of infrared light provide reliable and accurate measurements of the distances between the user and surrounding obstacles or surfaces. The haptic strap communicates the measured distances through an array of vibratory motors worn around the user's upper abdomen, providing haptic feedback. The linear vibration motors are combined with a point-loaded pretensioned applicator to transmit isolated vibrations to the user. We validated the device's capability in an extensive user study entailing 162 trials with 12 blind users. Users wearing the device successfully walked through hallways, avoided obstacles, and detected staircases.Andrea Bocelli FoundationNational Science Foundation (U.S.) (Grant NSF IIS1226883

Advancing proxy-based haptic feedback in virtual reality

This thesis advances haptic feedback for Virtual Reality (VR). Our work is guided by Sutherland's 1965 vision of the ultimate display, which calls for VR systems to control the existence of matter. To push towards this vision, we build upon proxy-based haptic feedback, a technique characterized by the use of passive tangible props. The goal of this thesis is to tackle the central drawback of this approach, namely, its inflexibility, which yet hinders it to fulfill the vision of the ultimate display. Guided by four research questions, we first showcase the applicability of proxy-based VR haptics by employing the technique for data exploration. We then extend the VR system's control over users' haptic impressions in three steps. First, we contribute the class of Dynamic Passive Haptic Feedback (DPHF) alongside two novel concepts for conveying kinesthetic properties, like virtual weight and shape, through weight-shifting and drag-changing proxies. Conceptually orthogonal to this, we study how visual-haptic illusions can be leveraged to unnoticeably redirect the user's hand when reaching towards props. Here, we contribute a novel perception-inspired algorithm for Body Warping-based Hand Redirection (HR), an open-source framework for HR, and psychophysical insights. The thesis concludes by proving that the combination of DPHF and HR can outperform the individual techniques in terms of the achievable flexibility of the proxy-based haptic feedback.Diese Arbeit widmet sich haptischem Feedback für Virtual Reality (VR) und ist inspiriert von Sutherlands Vision des ultimativen Displays, welche VR-Systemen die Fähigkeit zuschreibt, Materie kontrollieren zu können. Um dieser Vision näher zu kommen, baut die Arbeit auf dem Konzept proxy-basierter Haptik auf, bei der haptische Eindrücke durch anfassbare Requisiten vermittelt werden. Ziel ist es, diesem Ansatz die für die Realisierung eines ultimativen Displays nötige Flexibilität zu verleihen. Dazu bearbeiten wir vier Forschungsfragen und zeigen zunächst die Anwendbarkeit proxy-basierter Haptik durch den Einsatz der Technik zur Datenexploration. Anschließend untersuchen wir in drei Schritten, wie VR-Systeme mehr Kontrolle über haptische Eindrücke von Nutzern erhalten können. Hierzu stellen wir Dynamic Passive Haptic Feedback (DPHF) vor, sowie zwei Verfahren, die kinästhetische Eindrücke wie virtuelles Gewicht und Form durch Gewichtsverlagerung und Veränderung des Luftwiderstandes von Requisiten vermitteln. Zusätzlich untersuchen wir, wie visuell-haptische Illusionen die Hand des Nutzers beim Greifen nach Requisiten unbemerkt umlenken können. Dabei stellen wir einen neuen Algorithmus zur Body Warping-based Hand Redirection (HR), ein Open-Source-Framework, sowie psychophysische Erkenntnisse vor. Abschließend zeigen wir, dass die Kombination von DPHF und HR proxy-basierte Haptik noch flexibler machen kann, als es die einzelnen Techniken alleine können