Evaluation of the Oculus Rift S tracking system in room scale virtual reality

In specific virtual reality applications that require high accuracy it may be advisable to replace the built-in tracking system of the HMD with a third party solution. The purpose of this research work is to evaluate the accuracy of the built-in tracking system of the Oculus Rift S Head Mounted Display (HMD) in room scale environments against a motion capture system. In particular, an experimental evaluation of the Oculus Rift S inside-out tracking technology was carried out, compared to the performance of an outside-in tracking method based on the OptiTrack motion capture system. In order to track the pose of the HMD using the motion capture system the Oculus Rift S was instrumented with passive retro-reflective markers and calibrated. Experiments have been performed on a dataset of multiple paths including simple motions as well as more complex paths. Each recorded path contained simultaneous changes in both position and orientation of the HMD. Our results indicate that in room-scale environments the average translation error for the Oculus Rift S tracking system is about 1.83 cm, and the average rotation error is about 0. 77°, which is 2 orders of magnitude higher than the performance that can be achieved using a motion capture system

A novel experimental design of a real-time VR tracking device

Virtual Reality (VR) is progressively adopted at different stages of design and product development. Consequently, evolving interaction requirements in engineering design and development for VR are essential for technology adoption. One of these requirements is real-time positional tracking. This paper aims to present an experimental design of a new real-time positional tracking device (tracker), that is more compact than the existing solution, while addressing factors such as wearability and connectivity. We compare the simulation of the proposed device and the existing solution, discuss the results, and the limitations. The new experimental shape of the device is tailored towards research, allowing the engineering designer to take advantage of a new tracker alternative in new ways, and opens the door to new VR applications in research and product development

The Perception/Action loop: A Study on the Bandwidth of Human Perception and on Natural Human Computer Interaction for Immersive Virtual Reality Applications

Virtual Reality (VR) is an innovating technology which, in the last decade, has had a widespread success, mainly thanks to the release of low cost devices, which have contributed to the diversification of its domains of application. In particular, the current work mainly focuses on the general mechanisms underling perception/action loop in VR, in order to improve the design and implementation of applications for training and simulation in immersive VR, especially in the context of Industry 4.0 and the medical field. On the one hand, we want to understand how humans gather and process all the information presented in a virtual environment, through the evaluation of the visual system bandwidth. On the other hand, since interface has to be a sort of transparent layer allowing trainees to accomplish a task without directing any cognitive effort on the interaction itself, we compare two state of the art solutions for selection and manipulation tasks, a touchful one, the HTC Vive controllers, and a touchless vision-based one, the Leap Motion. To this aim we have developed ad hoc frameworks and methodologies. The software frameworks consist in the creation of VR scenarios, where the experimenter can choose the modality of interaction and the headset to be used and set experimental parameters, guaranteeing experiments repeatability and controlled conditions. The methodology includes the evaluation of performance, user experience and preferences, considering both quantitative and qualitative metrics derived from the collection and the analysis of heterogeneous data, as physiological and inertial sensors measurements, timing and self-assessment questionnaires. In general, VR has been found to be a powerful tool able to simulate specific situations in a realistic and involving way, eliciting user\u2019s sense of presence, without causing severe cybersickness, at least when interaction is limited to the peripersonal and near-action space. Moreover, when designing a VR application, it is possible to manipulate its features in order to trigger or avoid triggering specific emotions and voluntarily create potentially stressful or relaxing situations. Considering the ability of trainees to perceive and process information presented in an immersive virtual environment, results show that, when people are given enough time to build a gist of the scene, they are able to recognize a change with 0.75 accuracy when up to 8 elements are in the scene. For interaction, instead, when selection and manipulation tasks do not require fine movements, controllers and Leap Motion ensure comparable performance; whereas, when tasks are complex, the first solution turns out to be more stable and efficient, also because visual and audio feedback, provided as a substitute of the haptic one, does not substantially contribute to improve performance in the touchless case

Exploiting fashion x-commerce through the empowerment of voice in the fashion virtual reality arena. Integrating voice assistant and virtual reality technologies for fashion communication

The ongoing development of eXtended Reality (XR) technologies is supporting a rapid increase of their performances along with a progressive decrease of their costs, making them more and more attractive for a large class of consumers. As a result, their widespread use is expected within the next few years. This may foster new opportunities for e-commerce strategies, giving birth to an XR-based commerce (x-commerce) ecosystem. With respect to web and mobile-based shopping experiences, x-commerce could more easily support brick-and-mortar store-like experiences. One interesting and consolidated one amounts to the interactions among customers and shop assistants inside fashion stores. In this work, we concentrate on such aspects with the design and implementation of an XR-based shopping experience, where vocal dialogues with an Amazon Alexa virtual assistant are supported, to experiment with a more natural and familiar contact with the store environment. To verify the validity of such an approach, we asked a group of fashion experts to try two different XR store experiences: with and without the voice assistant integration. The users are then asked to answer a questionnaire to rate their experiences. The results support the hypothesis that vocal interactions may contribute to increasing the acceptance and comfortable perception of XR-based fashion shopping

Immersive virtual reality methods in cognitive neuroscience and neuropsychology: the Virtual Reality Everyday Assessment Lab (VR-EAL).an immersive neuropsychological test battery of everyday cognitive functions

In cognitive neuroscience and neuropsychology, the collection of cognitive and behavioural data is predominantly achieved by implementing paper-and-pencil and computerized (i.e., 2D and 3D applications) assessments. However, these psychometric tools in clinics and/or laboratories display several limitations and discrepancies between the observed performance in the laboratory/clinic and the actual performance of individuals in everyday life. The functional and predictive association between an individual's performance on a set of neuropsychological tests and the individual's performance in various everyday life settings is called ecological validity. Ecological validity is considered an important issue that cannot be resolved by the currently available assessment tools. Virtual reality head-mounted displays (HMD) appear to be effective research tools, which may address the problem of ecological validity in neuropsychological testing. However, their widespread implementation is hindered by virtual reality induced symptoms and effects (VRISE) and the lack of skills in virtual reality software development. In this PhD, a technological systematic literature review of the reasons for adverse symptomatology was conducted and suggestions and technological knowledge for the implementation of virtual reality HMD systems in cognitive neuroscience provided. The review indicated features pertinent to display, sound, motion tracking, navigation, ergonomic interactions, user experience, and computer hardware that should be considered by researchers. Subsequently, a meta-analysis of 44 neuroscientific or neuropsychological studies involving virtual reality HMD systems was performed. The meta-analysis of the virtual reality studies demonstrated that new generation HMDs induce significantly less VRISE and marginally fewer dropouts. Importantly, the commercial versions of the new generation HMDs with ergonomic interactions had zero incidents of adverse symptomatology and dropouts. HMDs equivalent to or greater than the commercial versions of contemporary HMDs accompanied with ergonomic interactions are suitable for implementation in cognitive neuroscience. Another aim of this PhD was to devise a brief tool to appraise and report both the quality of software features and VRISE intensity quantitatively; such a tool does not currently exist. The Virtual Reality Neuroscience Questionnaire (VRNQ; Kourtesis et al., 2019) was developed to assess the quality of virtual reality software in terms of user experience, game mechanics, in-game assistance, and VRISE. Forty participants aged between 28 and 43 years were recruited (18 gamers and 22 non-gamers) for the study. They participated in 3 different virtual reality sessions until they felt weary or discomfort and subsequently filled in the VRNQ. The results demonstrated that VRNQ is a valid tool for assessing virtual reality software as it has good convergent, discriminant, and construct validity. The maximum duration of virtual reality sessions should be between 55 and 70 min when the virtual reality software meets or exceeds the parsimonious cut-offs of the VRNQ, and the users are familiarized with the virtual reality system. Also, gaming experience does not affect how long virtual reality sessions should last. Furthermore, while the quality of virtual reality software substantially modulates the maximum duration of virtual reality sessions, age and education do not. Finally, deeper immersion, better quality of graphics and sound, and more helpful in-game instructions and prompts were found to reduce VRISE intensity. The VRNQ facilitates the brief assessment and reporting of the quality of virtual reality software features and/or the intensity of VRISE, while its minimum and parsimonious cut-offs may appraise the suitability of virtual reality software for implementation in research and clinical settings. However, the development of virtual reality software is predominantly dependent on third parties (e.g., freelancers or companies) with programming and software development skills. A solution that will promote the adoption of immersive virtual reality as a research and clinical tool might be the in-house development of virtual reality research/clinical software by computer science literate cognitive scientists or research software engineers. In Chapter 4, guidelines are offered for the development of virtual reality software in cognitive neuroscience and neuropsychology, by describing and discussing the stages of the development of Virtual Reality Everyday Assessment Lab (VR-EAL), the first neuropsychological battery in immersive virtual reality. Techniques for evaluating cognitive functions within a realistic storyline are discussed. The utility of various assets in Unity, software development kits, and other software are described so that cognitive scientists can overcome challenges pertinent to VRISE and the quality of the virtual reality software. In addition, VR-EAL is evaluated in accordance with the necessary criteria for virtual reality software for research purposes. The virtual reality neuroscience questionnaire (VRNQ) was implemented to appraise the quality of the three versions of VR-EAL in terms of user experience, game mechanics, in-game assistance, and VRISE. Twenty-five participants aged between 20 and 45 years with 12–16 years of full-time education evaluated various versions of VR-EAL. The final version of VR-EAL achieved high scores in every sub-score of the VRNQ and exceeded its parsimonious cut-offs. It also appeared to have better in-game assistance and game mechanics, while its improved graphics substantially increased the quality of the user experience and almost eradicated VRISE. The results substantially support the feasibility of the development of effective virtual reality research and clinical software without the presence of VRISE during a 60-min virtual reality session. In Chapter 5, validation of VR-EAL as an assessment of prospective memory, episodic memory, attention, and executive functions using an ecologically valid approach is examined. Performance on the VR-EAL, an immersive virtual reality neuropsychological battery, is examined against an extensive paper-and-pencil neuropsychological battery. Forty-one participants (21 females) were recruited: 18 gamers and 23 non-gamers who attended both an immersive virtual reality and a paper-and-pencil testing session. Bayesian Pearson correlation analyses were conducted to assess construct and convergent validity of the VR-EAL. Bayesian t-tests were performed to compare virtual reality and paper-and-pencil testing in terms of administration time, similarity to real life tasks (i.e., ecological validity), and pleasantness. VR-EAL scores were significantly correlated with their equivalent scores on the paper-and-pencil tests. The participants’ reports indicated that the VR-EAL tasks were considered significantly more ecologically valid and pleasant than the paper-and-pencil neuropsychological battery. The VR-EAL battery also had a shorter administration time. The VR-EAL appears to be an effective neuropsychological tool for the assessment of everyday cognitive functions, and has enhanced ecological validity, a highly pleasant testing experience, and does not induce cybersickness. In the final part of this thesis, the preparatory attentional and memory (PAM) and the multiprocess theories of prospective memory are examined by attempting to identify the cognitive functions which may predict the individual’s performance on ecologically valid prospective memory tasks in the same group of participants described in Chapter 5. Bayesian t-tests were conducted to explore the differences among different prospective memory tasks (e.g., event-based and time-based) and prospective memory tasks with varying delays between encoding and the recall of the intended action (e.g., short-delay versus long-delay). Bayesian linear regression analyses were performed to examine the predictors of VR-EAL scores. The results revealed that the type of prospective memory task does not play a significant role in everyday prospective memory functioning, but instead the length of delay between encoding and retrieving the prospective memory intention plays a central role. Support for the PAM and MP frameworks was found in non-focal and focal event-based tasks respectively. However, the findings, inferring a dynamic interplay between automatic and intentional monitoring and retrieval processes, agree with the inclusive approach of the multiprocess framework. Also, the role of executive functions appears crucial in everyday PM. Finally, everyday PM is predominantly facilitated by episodic memory, visuospatial attention, auditory attention, and executive functions. In conclusion, this PhD thesis attempted to show how immersive virtual reality research methods may be implemented efficiently without the confounding effect of cybersickness symptomatology in order to enhance the ecological validity of neuropsychological testing and contribute to our understanding of everyday cognitive ability

Freehand-Steering Locomotion Techniques for Immersive Virtual Environments: A Comparative Evaluation

Virtual reality has achieved significant popularity in recent years, and allowing users to move freely within an immersive virtual world has become an important factor critical to realize. The user’s interactions are generally designed to increase the perceived realism, but the locomotion techniques and how these affect the user’s task performance still represent an open issue, much discussed in the literature. In this article, we evaluate the efficiency and effectiveness of, and user preferences relating to, freehand locomotion techniques designed for an immersive virtual environment performed through hand gestures tracked by a sensor placed in the egocentric position and experienced through a head-mounted display. Three freehand locomotion techniques have been implemented and compared with each other, and with a baseline technique based on a controller, through qualitative and quantitative measures. An extensive user study conducted with 60 subjects shows that the proposed methods have a performance comparable to the use of the controller, further revealing the users’ preference for decoupling the locomotion in sub-tasks, even if this means renouncing precision and adapting the interaction to the possibilities of the tracker sensor