1,774 research outputs found

    A framework for geometry acquisition, 3-D printing, simulation, and measurement of head-related transfer functions with a focus on hearing-assistive devices

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    Individual head-related transfer functions (HRTFs) are essential in applications like fitting hearing-assistive devices (HADs) for providing accurate sound localization performance. Individual HRTFs are usually obtained through intricate acoustic measurements. This paper investigates the use of a three-dimensional (3D) head model for acquisition of individual HRTFs. Two aspects were investigated; whether a 3D-printed model can replace measurements on a human listener and whether numerical simulations can replace acoustic measurements. For this purpose, HRTFs were acoustically measured for four human listeners and for a 3D printed head model of one of these listeners. Further, HRTFs were simulated by applying the finite element method to the 3D head model. The monaural spectral features and spectral distortions were very similar between re-measurements and between human and printed measurements, however larger deviations were observed between measurement and simulation. The binaural cues were in agreement among all HRTFs of the same listener, indicating that the 3D model is able to provide localization cues potentially accessible to HAD users. Hence, the pipeline of geometry acquisition, printing, and acoustic measurements or simulations, seems to be a promising step forward towards in-silico design of HADs

    Cost-effective 3D scanning and printing technologies for outer ear reconstruction: Current status

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    Current 3D scanning and printing technologies offer not only state-of-the-art developments in the field of medical imaging and bio-engineering, but also cost and time effective solutions for surgical reconstruction procedures. Besides tissue engineering, where living cells are used, bio-compatible polymers or synthetic resin can be applied. The combination of 3D handheld scanning devices or volumetric imaging, (open-source) image processing packages, and 3D printers form a complete workflow chain that is capable of effective rapid prototyping of outer ear replicas. This paper reviews current possibilities and latest use cases for 3D-scanning, data processing and printing of outer ear replicas with a focus on low-cost solutions for rehabilitation engineering

    Perceptually Motivated Analysis of Numerically Simulated Head-Related Transfer Functions Generated By Various 3D Surface Scanning Systems

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    Numerical simulations offer a feasible alternative to the direct acoustic measurement of individual head-related transfer functions (HRTFs). For the acquisition of high quality 3D surface scans, as required for these simulations, several approaches exist. In this paper, we systematically analyze the variations between different approaches and evaluate the influence of the accuracy of 3D scans on the resulting simulated HRTFs. To assess this effect, HRTFs were numerically simulated based on 3D scans of the head and pinna of the FABIAN dummy head generated with 6 different methods. These HRTFs were analyzed in terms of interaural time difference, interaural level difference, energetic error in auditory filters and by their modeled localization performance. From the results, it is found that a geometric precision of about 1 mm is needed to maintain accurate localization cues, while a precision of about 4 mm is sufficient to maintain the overall spectral shape

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

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    Der Zugang zu digitalen Inhalten und Informationen wird immer wichtiger fĂŒr eine erfolgreiche Teilnahme an der heutigen, zunehmend digitalisierten Zivilgesellschaft. Solche Informationen werden meist visuell prĂ€sentiert, was den Zugang fĂŒr blinde und sehbehinderte Menschen einschrĂ€nkt. Die grundlegendste Barriere ist oft die elementare Orientierung und MobilitĂ€t (und folglich die soziale MobilitĂ€t), einschließlich der Erlangung von Kenntnissen ĂŒber unbekannte GebĂ€ude vor deren Besuch. Um solche Barrieren zu ĂŒberbrĂŒcken, sollten technische Hilfsmittel entwickelt und eingesetzt werden. Es ist ein Kompromiss zwischen technologisch niedrigschwellig zugĂ€nglichen und verbreitbaren Hilfsmitteln und interaktiv-adaptiven, aber komplexen Systemen erforderlich. Die Anpassung der Technologie der virtuellen RealitĂ€t (VR) umfasst ein breites Spektrum an Entwicklungs- und Entscheidungsoptionen. Die Hauptvorteile der VR-Technologie sind die erhöhte InteraktivitĂ€t, die Aktualisierbarkeit und die Möglichkeit, virtuelle RĂ€ume und Modelle als Abbilder von realen RĂ€umen zu erkunden, ohne dass reale Gefahren und die begrenzte VerfĂŒgbarkeit 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 ReprĂ€sentationen realer GebĂ€ude im Kontext von Orientierung und MobilitĂ€t berĂŒhrbar oder begehbar zu machen. Obwohl es bereits inhaltlich und technisch disjunkte Entwicklungen und Evaluationen zur VR-Technologie gibt, fehlt es an empirischer Evidenz. ZusĂ€tzlich bietet diese Arbeit einen Überblick ĂŒber 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 fĂŒr blinde und sehbehinderte Nutzer und der Weg dorthin durch die EinfĂŒhrung einer neuartigen Taxonomie diskutiert. Neben der Interaktion selbst werden Merkmale des Nutzers und des GerĂ€ts, der Anwendungskontext oder die nutzerzentrierte Entwicklung bzw. Evaluation als Klassifikatoren herangezogen. BegrĂŒndet und motiviert werden die folgenden Kapitel durch explorative AnsĂ€tze, d.h. im Bereich 'small scale' (mit sogenannten Datenhandschuhen) und im Bereich 'large scale' (mit einer avatargesteuerten VR-Fortbewegung). Die folgenden Kapitel fĂŒhren empirische Studien mit blinden und sehbehinderten Nutzern durch und geben einen formativen Einblick, wie virtuelle Objekte in Reichweite der HĂ€nde mit haptischem Feedback erfasst werden können und wie verschiedene Arten der VR-Fortbewegung zur Erkundung virtueller Umgebungen eingesetzt werden können. Daraus werden gerĂ€teunabhĂ€ngige technologische Möglichkeiten und auch Herausforderungen fĂŒr weitere Verbesserungen abgeleitet. Auf der Grundlage dieser Erkenntnisse kann sich die weitere Forschung auf Aspekte wie die spezifische Gestaltung interaktiver Elemente, zeitlich und rĂ€umlich 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)

    Accessibility of Health Data Representations for Older Adults: Challenges and Opportunities for Design

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    Health data of consumer off-the-shelf wearable devices is often conveyed to users through visual data representations and analyses. However, this is not always accessible to people with disabilities or older people due to low vision, cognitive impairments or literacy issues. Due to trade-offs between aesthetics predominance or information overload, real-time user feedback may not be conveyed easily from sensor devices through visual cues like graphs and texts. These difficulties may hinder critical data understanding. Additional auditory and tactile feedback can also provide immediate and accessible cues from these wearable devices, but it is necessary to understand existing data representation limitations initially. To avoid higher cognitive and visual overload, auditory and haptic cues can be designed to complement, replace or reinforce visual cues. In this paper, we outline the challenges in existing data representation and the necessary evidence to enhance the accessibility of health information from personal sensing devices used to monitor health parameters such as blood pressure, sleep, activity, heart rate and more. By creating innovative and inclusive user feedback, users will likely want to engage and interact with new devices and their own data

    Augmented Reality

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    Augmented Reality (AR) is a natural development from virtual reality (VR), which was developed several decades earlier. AR complements VR in many ways. Due to the advantages of the user being able to see both the real and virtual objects simultaneously, AR is far more intuitive, but it's not completely detached from human factors and other restrictions. AR doesn't consume as much time and effort in the applications because it's not required to construct the entire virtual scene and the environment. In this book, several new and emerging application areas of AR are presented and divided into three sections. The first section contains applications in outdoor and mobile AR, such as construction, restoration, security and surveillance. The second section deals with AR in medical, biological, and human bodies. The third and final section contains a number of new and useful applications in daily living and learning
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