Robustness and static-positional accuracy of the SteamVR 1.0 virtual reality tracking system

The use of low-cost immersive virtual reality systems is rapidly expanding. Several studies started to analyse the accuracy of virtual reality tracking systems, but they did not consider in depth the effects of external interferences in the working area. In line with that, this study aimed at exploring the static-positional accuracy and the robustness to occlusions inside the capture volume of the SteamVR (1.0) tracking system. To do so, we ran 3 different tests in which we acquired the position of HTC Vive PRO Trackers (2018 version) on specific points of a grid drawn on the floor, in regular tracking conditions and with partial and total occlusions. The tracking system showed a high inter- and intra-rater reliability and detected a tilted surface with respect to the floor plane. Every acquisition was characterised by an initial random offset. We estimated an average accuracy of 0.5 +/- 0.2 cm across the entire grid (XY-plane), noticing that the central points were more accurate (0.4 +/- 0.1 cm) than the outer ones (0.6 +/- 0.1 cm). For the Z-axis, the measurements showed greater variability and the accuracy was equal to 1.7 +/- 1.2 cm. Occlusion response was tested using nonparametric Bland-Altman statistics, which highlighted the robustness of the tracking system. In conclusion, our results promote the SteamVR system for static measures in the clinical field. The computed error can be considered clinically irrelevant for exercises aimed at the rehabilitation of functional movements, whose several motor outcomes are generally measured on the scale of metres

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

Motion Generation and Planning System for a Virtual Reality Motion Simulator: Development, Integration, and Analysis

In the past five years, the advent of virtual reality devices has significantly influenced research in the field of immersion in a virtual world. In addition to the visual input, the motion cues play a vital role in the sense of presence and the factor of engagement in a virtual environment. This thesis aims to develop a motion generation and planning system for the SP7 motion simulator. SP7 is a parallel robotic manipulator in a 6RSS-R configuration. The motion generation system must be able to produce accurate motion data that matches the visual and audio signals. In this research, two different system workflows have been developed, the first for creating custom visual, audio, and motion cues, while the second for extracting the required motion data from an existing game or simulation. Motion data from the motion generation system are not bounded, while motion simulator movements are limited. The motion planning system commonly known as the motion cueing algorithm is used to create an effective illusion within the limited capabilities of the motion platform. Appropriate and effective motion cues could be achieved by a proper understanding of the perception of human motion, in particular the functioning of the vestibular system. A classical motion cueing has been developed using the model of the semi-circular canal and otoliths. A procedural implementation of the motion cueing algorithm has been described in this thesis. We have integrated all components together to make this robotic mechanism into a VR motion simulator. In general, the performance of the motion simulator is measured by the quality of the motion perceived on the platform by the user. As a result, a novel methodology for the systematic subjective evaluation of the SP7 with a pool of juries was developed to check the quality of motion perception. Based on the results of the evaluation, key issues related to the current configuration of the SP7 have been identified. Minor issues were rectified on the flow, so they were not extensively reported in this thesis. Two major issues have been addressed extensively, namely the parameter tuning of the motion cueing algorithm and the motion compensation of the visual signal in virtual reality devices. The first issue was resolved by developing a tuning strategy with an abstraction layer concept derived from the outcome of the novel technique for the objective assessment of the motion cueing algorithm. The origin of the second problem was found to be a calibration problem of the Vive lighthouse tracking system. So, a thorough experimental study was performed to obtain the optimal calibrated environment. This was achieved by benchmarking the dynamic position tracking performance of the Vive lighthouse tracking system using an industrial serial robot as a ground truth system. With the resolution of the identified issues, a general-purpose virtual reality motion simulator has been developed that is capable of creating custom visual, audio, and motion cues and of executing motion planning for a robotic manipulator with a human motion perception constraint

Dynamic Pose Tracking Performance Evaluation of HTC Vive Virtual Reality System

Virtual reality tracking devices are rapidly becoming the go-to system for cost-effective motion tracking solutions across different communities such as robotics, biomechanics, sports, rehabilitation, motion simulators, etc. This article focuses on the spatial tracking performance of HTC Vive's lighthouse tracking system (VLTS) devices (tracker, controller, and head mount display). A comprehensive literature survey on the performance analysis of VLTS on the various aspects is presented along with its shortcomings in terms of spatial tracking evaluation. The two key limitations have been identified: in static cases, there is a lack of standard procedures and criteria, and in dynamic cases, the entire study of spatial tracking. We address the first by assessing VLTS using the optical tracking system standard specified by ASTM International, and the latter by revising the standards to determine the upper-velocity limit for reliable tracking. The findings are substantiated with the trajectories of human wrist motion. Each evaluation's results are systematically analyzed with statistical hypothesis tests and criteria fulfillment. Comau NS16, an industrial serial robot, was used as the ground truth motion generator due to its repeatability and 6 degrees of workspace freedom. One of the major reasons for not having more generalized spatial tracking studies is that the tracking performance heavily depends on the configurations of the setup, work volume, environment, etc. Thus, the guidelines for configuring VLTS and the approach adapted from ASTM standards for evaluating VLTS for custom applications using our reported findings for both static and dynamic cases are included in the appendix

Constrained Localization: A Survey

International audienceIndoor localization techniques have been extensively studied in the last decade. The wellestablished technologies enable the development of Real-Time Location Systems (RTLS). A good body of publications emerged, with several survey papers that provide a deep analysis of the research advances. Existing survey papers focus on either a specific technique and technology or on a general overview of indoor localization research. However, there is a need for a use case-driven survey on both recent academic research and commercial trends, as well as a hands-on evaluation of commercial solutions. This work aims at helping researchers select the appropriate technology and technique suitable for developing low-cost, low-power localization system, capable of providing centimeter level accuracy. The article is both a survey on recent academic research and a hands-on evaluation of commercial solutions. We introduce a specific use case as a guiding application throughout this article: localizing low-cost low-power miniature wireless swarm robots. We define a taxonomy and classify academic research according to five criteria: Line of Sight (LoS) requirement, accuracy, update rate, battery life, cost. We discuss localization fundamentals, the different technologies and techniques, as well as recent commercial developments and trends. Besides the traditional taxonomy and survey, this article also presents a hands-on evaluation of popular commercial localization solutions based on Bluetooth Angle of Arrival (AoA) and Ultra-Wideband (UWB). We conclude this article by discussing the five most important open research challenges: lightweight filtering algorithms, zero infrastructure dependency, low-power operation, security, and standardization

The effectiveness of training in virtual environments

The research presented in this thesis explores the use of consumer virtual reality technology for training, comparing its validity to more traditional training formats. The need to evaluate the effectiveness of training in virtual environments is critical as a wider audience gains access to an array of emerging virtual reality consumer devices. Training is an obvious use case for these devices. This is motivated by the well-known success of domain-specific training simulators, the ability to train in safe, controlled environments and the potential to launch training programs when the physical components required to complete a task are not readily available. In this thesis, we present four user studies that aim to compare the effectiveness of systems with varying levels of immersion for learning transfer of several tasks, ranging from object location spatial memory to more complex assembly procedures. For every study, evaluation of the effectiveness of training took place in a real-world, physical environment. The first two studies compare geometric and self-motion models in describing human spatial memory through scale distortions of real and virtual environments. The third study examines the effect of level of immersion, self-avatar and environmental fidelity on object location memory in real and virtual environments. The fourth study compares the effectiveness of physical training and virtual training for teaching a bimanual assembly task. Results highlight the validity of virtual environments for training. The overall conclusion is that virtual training can yield a resulting performance that is superior to other, more traditional training formats. Combined, the outcomes of each of the user studies motivate further study of consumer virtual reality systems in training and suggest considerations for the design of such virtual environments

Collaborative Interaction Techniques in Virtual Reality for Emergency Management

Virtual Reality (VR) technology has had many interesting applications over the last decades. It can be seen in a multitude of industries: entertainment, education, tourism to crisis management among others. Many of them, feature collaborative uses of VR technology. This thesis presents the design, development and evaluation of a multi-user VR system, aimed at collaborative usage focused on a crisis scenario based on real-life wildfire as the use case. The system also features a dual-map interface to display geographical information, providing both two-dimensional and three-dimensional views over the region and data relevant to the scenario. The main goals of this thesis are to understand how people can collaborate in VR, test which interface is preferred, as well as what kinds of notification mechanisms are more user friendly. The Virtual Environment (VE) displays relevant geo-located information, such as roads, towns, vehicles and the wildfire itself, in a dual-map setup, in two and three dimensions. Users are able to share the environment and, simultaneously, use available tools to interact with the maps and communicate with each other, while controlling the wildfire playback time to understand how it propagates. Actions such as drawing, measuring distances, directing vehicles and notifying other users are available. Users can propose actions that can then be accepted or denied. Eighteen subjects took part in a user study to evaluate the application. Participants were asked to perform several tasks, using the tools available, while sharing that same environment with the researcher. Upon analyzing data from the testing sessions, it is possible to state that most users agree they would be able to use the system to collaborate. The results also support the presence of both types of map interfaces, two-dimensional and three-dimensional, as they are objectively better suited for different tasks; users, subjectively, affirmed preference for both of them, depending on the task at hand.A Realidade Virtual (RV) tem demonstrado ter várias aplicações interessantes ao longo das últimas décadas. Faz parte de múltiplas indústrias, tais como entertenimento, educação, turismo, gestão de crises, entre outras. Muitas delas usam a tecnologia num contexto colaborativo. Nesta tese é apresentado o design, desenvolvimento e avaliação de um sistema multiutilizador de RV, dedicado ao uso colaborativo durante um cenário de crise baseado num fogo real. É também implementada uma interface dual-map que visualiza informação geográfica, providenciando duas vistas (2D e 3D) sobre a região e dados relevantes ao cenário descrito. Perceber como podem as pessoas colaborar em RV, testar qual a interface preferida e quais os tipos de mecanismos de notificação preferíveis são os objectivos principais desta tese. O Ambiente Virtual (AV) apresenta informação geo-referenciada relevante, como estradas, povoações, veículos e o próprio incêndio, através da interface dual. Utilizadores podem partilhar o ambiente e, simultaneamente, usar as ferramentas disponíveis para interagir com os mapas e comunicar entre si, enquanto controlam o progresso do incêndio para melhor entender como se propaga. Ações como desenhar, medir distâncias, direcionar veículos e notificar outros utilizadores estão disponíveis. Utilizadores podem também propor ações que serão aceites ou recusadas. Dezoito pessoas fizeram parte do estudo de utilizador para avaliar a aplicação. Os participantes executaram múltiplas tarefas, usando as ferramentas disponíveis, enquanto partilhavam o mesmo AV que o investigador. Após análise dos dados gerados, é possível afirmar que a maioria dos participantes consideram que seriam capazes de usar o sistema para colaborar. Os resultados também suportam a presença de ambos os tipos de mapas, 2D e 3D, pois ambos são objectivamente melhores para tarefas distintas; participantes, subjectivamente, afirmam preferência por ambas, dependendo da tarefa a executar

Measuring user experience for virtual reality

In recent years, Virtual Reality (VR) and 3D User Interfaces (3DUI) have seen a drastic increase in popularity, especially in terms of consumer-ready hardware and software. These technologies have the potential to create new experiences that combine the advantages of reality and virtuality. While the technology for input as well as output devices is market ready, only a few solutions for everyday VR - online shopping, games, or movies - exist, and empirical knowledge about performance and user preferences is lacking. All this makes the development and design of human-centered user interfaces for VR a great challenge. This thesis investigates the evaluation and design of interactive VR experiences. We introduce the Virtual Reality User Experience (VRUX) model based on VR-specific external factors and evaluation metrics such as task performance and user preference. Based on our novel UX evaluation approach, we contribute by exploring the following directions: shopping in virtual environments, as well as text entry and menu control in the context of everyday VR. Along with this, we summarize our findings by design spaces and guidelines for choosing optimal interfaces and controls in VR.In den letzten Jahren haben Virtual Reality (VR) und 3D User Interfaces (3DUI) stark an Popularität gewonnen, insbesondere bei Hard- und Software im Konsumerbereich. Diese Technologien haben das Potenzial, neue Erfahrungen zu schaffen, die die Vorteile von Realität und Virtualität kombinieren. Während die Technologie sowohl für Eingabe- als auch für Ausgabegeräte marktreif ist, existieren nur wenige Lösungen für den Alltag in VR - wie Online-Shopping, Spiele oder Filme - und es fehlt an empirischem Wissen über Leistung und Benutzerpräferenzen. Dies macht die Entwicklung und Gestaltung von benutzerzentrierten Benutzeroberflächen für VR zu einer großen Herausforderung. Diese Arbeit beschäftigt sich mit der Evaluation und Gestaltung von interaktiven VR-Erfahrungen. Es wird das Virtual Reality User Experience (VRUX)- Modell eingeführt, das auf VR-spezifischen externen Faktoren und Bewertungskennzahlen wie Leistung und Benutzerpräferenz basiert. Basierend auf unserem neuartigen UX-Evaluierungsansatz leisten wir einen Beitrag, indem wir folgende interaktive Anwendungsbereiche untersuchen: Einkaufen in virtuellen Umgebungen sowie Texteingabe und Menüsteuerung im Kontext des täglichen VR. Die Ergebnisse werden außerdem mittels Richtlinien zur Auswahl optimaler Schnittstellen in VR zusammengefasst

Determining principles for the development of mixed reality systems for command and control applications

The pace of advancement in emerging display and interface technologies supporting the development of mixed reality systems – those that exploit the existence of real-world objects to enhance the believability of virtual objects – is rapidly increasing. However, the availability of relevant human-system design standards underpinning the exploitation of interfaces is significantly lagging behind. To provide supporting principles to aid in the development and deployment of mixed reality systems, a series of studies was conducted to systematically investigate a range of design parameters relevant to mixed reality, and to determine the impact of those parameters on human-system performance, including cognitive and physical demands. An assessment of specific design standards was undertaken related to the performance of fundamental human-system interaction tasks in a mixed reality system. It was found that mixed reality is most suited to selection tasks, as opposed to more complex interaction tasks such as repositioning and rescaling virtual objects in 3D space. An evaluation was also made of the effects on presence of introducing physical “tangible” interface elements co-located with virtual content. The findings show that tangible interface objects have a significant positive effect on presence, in addition to usability and workload. Finally, an investigation was undertaken to assess the effects of vibration — a common, uncontrollable environmental condition — on human-system performance. Vibration is shown to have a significantly larger impact on accuracy for eye-based input than on head-based input when performing dwell-based interaction. The lowest frequencies have the greatest effect on accuracy, with higher frequencies producing similar effects to instances of zero vibration