Pseudo-Haptics for Rigid Tool/Soft Object Interaction Feedback in Virtual Environments

This paper proposes a novel pseudo-haptics soft object stiffness simulation technique which is a marked improvement to currently used simulation methods and an effective low-cost alternative to expensive 3-DOF haptic devices. Soft object stiffness simulation is achieved by maneuvering an indenter avatar over the surface of a virtual soft object by means of an input device, such as a mouse, a joystick, or a touch-sensitive tablet. The alterations to the indenter avatar behavior produced by the proposed technique create for the user the illusion of interaction with a hard inclusion embedded in the soft object. The proposed pseudo-haptics technique is validated with a series of experiments conducted by employing three types of 2-DOF force-sensitive haptic surfaces, including a touchpad, a tablet with an S-pen input, and a tablet with a bare finger input. It is found that both the sensitivity and the positive predictive value of hard inclusion detection can be significantly improved by 33.3% and 13.9% respectively by employing tablet computers. Using tablet computers could produce results comparable to direct hand touch in detecting hard inclusions in a soft object. The experimental results presented here confirm the potential of the proposed technique for conveying haptic information in rigid tool / soft object interaction in virtual environments

The impact of visual cues on haptic compliance discrimination using a pseudo-haptic robotic system

A psychophysical magnitude estimation experiment was set up to determine the extent of the contribution of visual feedback during haptic compliance discrimination. Subjects remotely palpated physical compliant samples using a novel pseudo-haptic feedback system which allowed for independent manipulation of visual and haptic feedback. Subjects were asked to rate the compliance of a test sample based on that of a reference sample. While visual feedback was modified by switching the physical test samples shown to participants during indentation, haptic compliance of the test samples was always identical to that of the reference sample. Any variations in haptic sensation was a result of pseudo-haptic illusions. Ratings were collated and fitted to Steven's power law as well as Weber's law. A 0.18 power exponent suggests that the system was successful in generating viscoelastic properties through variations in visual information only. A 19.6% visual change from the reference compliance was necessary in order to perceive a change in haptic compliance using the pseudo-haptic system. These findings could prove beneficial in research and educationalfacilities where advanced force feedback devices are limited or inaccessible, where the concept of pseudo-haptics could be used to simulate various mechanical properties of virtual tissue for training purposes without the needfor complicated or costly force feedback

Elastic Images: Perceiving Local Elasticity of Images Through a Novel Pseudo-Haptic Deformation Effect

International audienceWe introduce the Elastic Images, a novel pseudo-haptic feedback technique which enables the perception of the local elasticity of images without the need of any haptic device. The proposed approach focus on whether visual feedback is able to induce a sensation of stiffness when the user interacts with an image using a standard mouse. The user, when clicking on a Elastic Image, is able to deform it locally according to its elastic properties. To reinforce the effect, we also propose the generation of procedural shadows and creases to simulate the compressibility of the image and several mouse cursors replacements to enhance pressure and stiffness perception. A psychophysical experiment was conducted to quantify this novel pseudo-haptic perception and determine its perceptual threshold (or its Just Noticeable Difference). The results showed that users were able to recognize up to eight different stiffness values with our proposed method and confirmed that it provides a perceivable and exploitable sensation of elasticity. The potential applications of the proposed approach range from pressure sensing in product catalogs and games, or its usage in graphical user interfaces for increasing the expressiveness of widgets

Expressive feedback from virtual buttons

The simple action of pressing a button is a multimodal interaction with an interesting depth of complexity. As the development of computer interfaces to support 3D tasks evolves, there is a need to better understand how users will interact with virtual buttons that generate feedback from multiple sensory modalities. This research examined the effects of visual, auditory, and haptic feedback from virtual buttons on task performance dialing phone numbers and on the motion of individual buttons presses. This research also presents a theoretical framework for virtual button feedback and a model of virtual button feedback that includes touch feedback hysteresis. The results suggest that although haptic feedback alone was not enough to prevent participants from pressing the button farther than necessary, bimodal and trimodal feedback combinations that included haptic feedback shortened the depth of the presses. However, the shallower presses observed during trimodal feedback may have led to a counterintuitive increase in the number of digits that the participants omitted during the task. Even though interaction with virtual buttons may appear simple, it is important to understand the complexities behind the multimodal interaction because users will seek out the multimodal interactions they prefer

Interaction avec des environnements virtuels affichés au moyens d'interfaces de visualisation collective

Les interfaces de visualisation collective à base de grands écrans permettent à plusieurs participants, localisés en un lieu unique, d'être immergés dans un même environnement virtuel (EV). Malgré leur potentiel pour le travail de groupe, ces interfaces restent souvent sousutilis ées, car les utilisateurs n'ont pas la possibilité d'interagir facilement et efficacement avec les EV qu'ils sont en train de visualiser. Nous nous proposons d'étudier les caractéristiques des interfaces de visualisation collective afin de définir un ensemble de recommandations pour l'interaction avec des EV. A partir de ces recommandations, nous critiquons les interfaces d'action existantes et proposons une nouvelle interface appelée le CAT. Le CAT est une interface d'action à six degrés de liberté fonctionnant à partir de modes de résistances isotoniques et isométriques. Un plateau mobile articulé autour d'un pied fixe permet la réalisation de tâches d'interaction 3D (navigation, manipulation). Une tablette graphique, fixée sur le plateau permet la réalisation de tâches d'interaction 2D (sélection, contrôle du système). La structure du CAT favorise une interaction non contraignante, rapide et efficace pour des utilisateurs novices. Une évaluation formelle a permis de montrer que le CAT était plus performant qu'une spacemouse pour des tâches de manipulation d'objets 3D, et que les préférences des utilisateurs étaient en sa faveur. Le CAT a été utilisé pour des applications de revue de projet et de théâtre interactif. Cette nouvelle interface d'action favorise le développement d'applications concrètes utilisant des EV affichés au moyen d'interfaces de visualisation collective.Large-displays used as collective visualization interfaces allow several co-located participants to be immersed in virtual environments (VE). In spite of their potential for group works, large-displays are often under-used because the users cannot interact easily and e_ciently with the visualized VE. The study of the characteristics of the large-displays allows us to propose a set of recommendations for interaction with the VE. From these recommendations, we criticize the existing input devices, and propose a new input device : the CAT (Control Action Table). The CAT is a 6 degrees of freedom device mixing isotonic and isometric resistance modes. It consists of a freestanding sensitive top, which can be orientated in space. The manipulation of this top allows to perform 3D tasks (manipulation, navigation). A tablet, _xed on the top, allows to perform 2D tasks (selection, system control). The CAT design favours a nonconstraining, quick and e_cient interaction for novice users. A user study has shown that the CAT is more e_cient than a standard 6 DOF rate controller for 3D manipulation tasks, and that the user preferences are in its favour. The CAT has been used for applications of project review and interactive theatre. This new input device favours the development of real applications using VE visualized on large-displays

Determining the Contribution of Visual and Haptic Cues during Compliance Discrimination in the Context of Minimally Invasive Surgery

While minimally invasive surgery is replacing open surgery in an increasing number of surgical procedures, it still poses risks such as unintended tissue damage due to reduced visual and haptic feedback. Surgeons assess tissue health by analysing mechanical properties such as compliance. The literature shows that while both types of feedback contribute to the final percept, visual information is dominant during compliance discrimination tasks. The magnitude of that contribution, however, was never quantitatively determined. To determine the effect of the type of visual feedback on compliance discrimination, a psychophysical experiment was set up using different combinations of direct and indirect visual and haptic cues. Results reiterated the significance of visual information and suggested a visio-haptic cross-modal integration. Consequently, to determine which cues contributed most to visual feedback, the impact of force and position on the ability to discriminate compliance using visual information only was assessed. Results showed that isolating force and position cues during indentation enhanced performance. Furthermore, under force and position constraints, visual information was shown to be sufficient to determine the compliance of deformable objects. A pseudo-haptic feedback system was developed to quantitatively determine the contribution of visual feedback during compliance discrimination. A psychophysical experiment showed that the system realistically simulated viscoelastic behaviour of compliant objects. Through a magnitude estimation experiment, the pseudo-haptic system was shown to be successful at generating haptic sensations of compliance during stimuli indentation only by modifying the visual feedback presented to participants. This can be implemented in research and educational facilities where advanced force feedback devices are inaccessible. Moreover, it can be incorporated into virtual reality simulators to enhance force ranges. Future work will assess the value of visual cue augmentation in more complicated surgical tasks

Spatially-localized correlation of MRI and mechanical stiffness to assess cartilage integrity in the human tibial plateau

Thesis (Ph.D.)--Harvard--Massachusetts Institute of Technology Division of Health Sciences and Technology, 2002.Includes bibliographical references (p. 216-225).Osteoarthritis is a painful degenerative joint disease affecting millions of people in the U.S. The pathogenesis of articular cartilage disease is characterized by softening of cartilage and loss and disruption of constituent macromolecules including proteoglycans and collagen. In current orthopaedic surgical practice, the gold standard for evaluating articular cartilage integrity is the use of a hand probe during arthroscopy. Mechanical probing, however, is invasive and requires anesthesia. Tightly confined areas of the articular surface can be difficult to reach and assess, and manual probing provides a subjective rather than a quantitative assessment of cartilage mechanical integrity. This thesis was motivated by the desire for a noninvasive and nondestructive means to map the variation in mechanical stiffness of an articular surface. Such a method could potentially have application to guiding surgeons during procedures and quantitatively assessing the efficacy of medical and surgical therapies. It could also potentially provide patient-specific, in vivo tissue mechanical property data for surgical simulation and preoperative procedure planning. The macromolecule glycosaminoglycan (GAG) is a significant determinant of cartilage stiffness. GAG content can be assessed noninvasively in vivo and in vitro by an MRI-based technique known as delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC), which measures the MRI parameter TI after equilibration with the ionic contrast agent Gd(DTPA)2-. With dGEMRIC, TlGd serves as an index of GAG content: we therefore examined whether cartilage stiffness could be related to dGEMRIC-measured TlGd in samples of human tibial plateaus.(cont.) We developed an experimental methodology to permit indentation test sites and regions in dGEMRIC scans to be registered with submillimeter accuracy. We found that the load response to focal indentation (a measure of local stiffness) and locally-averaged TlGd were in general highly correlated (Pearson correlation coefficients r = .80, .90, .64, .81 (p < .002) for four different patient samples, 130 total test locations). We further demonstrated that the observed correlation is not a simple consequence of cartilage thickness effects. We observed that the parameters of the stiffness-TIGd relationship differed in some samples between the region of the tibial plateau covered by the meniscus in vivo and the more central region normally in contact with the femoral condyle. This suggests that another factor such as surface architecture or collagen integrity also influences the indentation response of the articular surface.by Joseph Thomas Samosky.Ph.D

Advances on Mechanics, Design Engineering and Manufacturing III

This open access book gathers contributions presented at the International Joint Conference on Mechanics, Design Engineering and Advanced Manufacturing (JCM 2020), held as a web conference on June 2–4, 2020. It reports on cutting-edge topics in product design and manufacturing, such as industrial methods for integrated product and process design; innovative design; and computer-aided design. Further topics covered include virtual simulation and reverse engineering; additive manufacturing; product manufacturing; engineering methods in medicine and education; representation techniques; and nautical, aeronautics and aerospace design and modeling. The book is organized into four main parts, reflecting the focus and primary themes of the conference. The contributions presented here not only provide researchers, engineers and experts in a range of industrial engineering subfields with extensive information to support their daily work; they are also intended to stimulate new research directions, advanced applications of the methods discussed and future interdisciplinary collaborations

Using binaural audio for inducing intersensory illusions to create illusory tactile feedback in virtual reality

Virtual reality has the potential to simulate a variety of real-world scenarios for training- and entertainment-purposes, as it has the ability to induce a sense of “presence”: the illusion that the user is physically transported to another location and is really “there”. VR and VR-technologies have seen a recent market resurgence due to the arrival of affordable, mass-market VR-display systems, such as the Oculus Rift, HTC Vive, PlayStation VR, Samsung GearVR, and Google Cardboard. However, the use of tactile feedback to convey information about the virtual environment is often lacking in VR applications. This study addresses this lack by proposing the use of binaural audio in VR to induce illusory tactile feedback. This is done by examining the literature on intersensory illusions as well as the relationship between audio and tactile feedback to inform the design of a software prototype that is able to induce the desired feedback. This prototype is used to test the viability of such an approach to induce illusory tactile feedback and to investigate the nature of this feedback. The software prototype is used to collect data from users regarding their experiences of this type of feedback and its underlying causes. Data collection is done through observation, questionnaires, interviews, and focus groups and the results indicate that the use of binaural audio in VR can be used to effectively induce an illusory sense of tactile feedback in the absence of real-world feedback. This study contributes insights regarding the nature of illusory sensations in VR, focusing on touch-sensations. This study also provides consolidated definitions of immersion and presence as well as a consolidated list of aspects of immersion, both of which are used to detail the relationship between immersion, presence, and illusory tactile feedback. Findings provide insight into the relationship between the design of audio in VR and its ability to alter perception in the tactile modality. Findings also provide insight into aspects of VR, such as presence and believability, and their relationship to perception across various sensory modalities.Dissertation (MIS)--University of Pretoria 2018.Information ScienceMISUnrestricte

Gestaltung visuell-haptischer Telepräsenz- und Teleaktionssysteme mittels psychologischer Grundlagen

Vor dem Hintergrund multimodaler Displays zukünftiger TPTA-Systeme wurde in dieser Arbeit die unimodal haptische und bimodale visuell-haptische Wahrnehmungsfähigkeit des Menschen beim Explorieren unterschiedlicher Materialproben untersucht und das menschliche Auflösungsvermögen in Abhängigkeit der Variation physikalischer Parameter bestimmt. Hierzu waren als relevante Materialeigenschaften Textur, bzw. Körnigkeit, und Härte, bzw. Nachgiebigkeit, sowie als bestimmende geometrische Eigenschaft, die Objektkante, ausgewählt worden