Using remote vision: The effects of video image frame rate on visual object recognition performance

This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2010 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.The process of using remote vision was simulated in order to determine the effects of video image frame rate on the performance in visual recognition of stationary environmental hazards in the dynamic video footage of the pedestrian travel environment. The recognition performance was assessed against two different video image frame rate variations: 25 and 2 fps. The assessment included a range of objective and subjective criteria. The obtained results show that the effects of the frame rate variations on the performance are statistically insignificant. This paper belongs to the process of development of a novel system for navigation of visually impaired pedestrians. The navigation system includes a remote vision facility, and the visual recognition of the environmental hazards by the sighted human guide is a basic activity in aiding the visually impaired user of the system in mobility

Effects of hyperlinks on navigation in virtual environments

Hyperlinks introduce discontinuities of movement to 3-D virtual environments (VEs). Nine independent attributes of hyperlinks are defined and their likely effects on navigation in VEs are discussed. Four experiments are described in which participants repeatedly navigated VEs that were either conventional (i.e. obeyed the laws of Euclidean space), or contained hyperlinks. Participants learned spatial knowledge slowly in both types of environment, echoing the findings of previous studies that used conventional VEs. The detrimental effects on participants' spatial knowledge of using hyperlinks for movement were reduced when a time-delay was introduced, but participants still developed less accurate knowledge than they did in the conventional VEs. Visual continuity had a greater influence on participants' rate of learning than continuity of movement, and participants were able to exploit hyperlinks that connected together disparate regions of a VE to reduce travel time

Analysis domain model for shared virtual environments

The field of shared virtual environments, which also encompasses online games and social 3D environments, has a system landscape consisting of multiple solutions that share great functional overlap. However, there is little system interoperability between the different solutions. A shared virtual environment has an associated problem domain that is highly complex raising difficult challenges to the development process, starting with the architectural design of the underlying system. This paper has two main contributions. The first contribution is a broad domain analysis of shared virtual environments, which enables developers to have a better understanding of the whole rather than the part(s). The second contribution is a reference domain model for discussing and describing solutions - the Analysis Domain Model

Development and Testing of A Wearable Vibrotactile Haptic Feedback System For Proprioceptive Rehabilitation

The human sense of touch is an integral part of daily life. For tasks involving grasping and manipulation of objects, force feedback is a key requirement. Most of the systems give contact point or complete grasping force feedback; for precision grasping and other physical interactions, finger awareness and force feedback from independent fingers is essential. In this study a novel, wearable proprioceptive rehabilitation system is designed which restores the ability of identifying and distinguishing between individual fingers of a prosthetic hand or an exoskeleton in a non-invasive manner. Moreover, it provides different levels of force feedback from every finger as well, which enables the user to distinguish and control force in precision grasping activities. For testing the system accuracy, classical psychophysical methods were used on a group of 14 voluntary disabled subjects. The tests were conducted in both, ideal and real-world conditions i.e. without and with distractions and accuracies were calculated accordingly. A p-test was also conducted to observe significance between the samples of with and without distraction datasets. The system performed with an overall accuracy of 82.04% which was well above the min. performance measure of 60%. Vi-HaB is standalone system and can be mounted on any upper limb rehabilitation (prosthesis, exoskeleton) system for finger awareness and force feedback

User Experience in Virtual Reality, conducting an evaluation on multiple characteristics of a Virtual Reality Experience

Virtual Reality applications are today numerous and cover a wide range of interests and tastes. As popularity of Virtual Reality increases, developers in industry are trying to create engrossing and exciting experiences that captivate the interest of users. User-Experience, a term used in the field of Human-Computer Interaction and Interaction Design, describes multiple characteristics of the experience of a person interacting with a product or a system. Evaluating User-Experience can provide valuable insight to developers and researchers on the thoughts and impressions of the end users in relation to a system. However, little information exists regarding on how to conduct User-Experience evaluations in the context of Virtual Reality. Consecutively, due to the numerous parameters that influence User-Experience in Virtual Reality, conducting and organizing evaluations can be overwhelming and challenging. The author of this thesis investigated how to conduct a User-Experience evaluation on multiple aspects of a Virtual Reality headset by identifying characteristics of the experience, and the methods that can be used to measure and evaluate them. The data collected was both qualitative and quantitative to cover a wide range of characteristics of the experience. Furthermore, the author applied usability testing, think-aloud protocol, questionnaires and semi-structured interview as methods to observe user behavior and collect information regarding the aspects of the Virtual Reality headset. The testing session described in this study included 14 participants. Data from this study showed that the combination of chosen methods were able to provide adequate information regarding the experience of the users despite encountered difficulties. Additionally, this thesis showcases which methods were used to evaluate specific aspects of the experience and the performance of each method as findings of the study

Perzeption in virtueller Realität als Aggregat von Visualisierung und Interaktion

Die vorliegende Arbeit belegt, dass sich das varianzanalytische Design mit Messwiederholung zur vergleichenden Untersuchung verschiedener Anzeigesysteme und Interaktionstechniken eignet. Darüber hinaus eröffnet das forschungsmethodische Instrument die Aufnahme weiterer Variablen, von denen ein Einfluss auf Performanz, sense of  resence, usability sowie auf weitere abhängige Variablen im Kontext virtueller Umgebungen zu erwarten ist. Weiterhin sind die Reliabilitäten der Fragebögen als zufrieden stellend und gut einzuordnen, wonach  sich der Einsatz der Instrumente empfiehlt, wenngleich umfassende Studien zur Validität noch ausstehen

Assessment of a hand exoskeleton on proximal and distal training in virtual environments for robot mediated upper extremity rehabilitation

Stroke is the leading cause of disability in the United States with approximately 800,000 cases per year. This cerebral vascular accident results in neurological impairments that reduce limb function and limit the daily independence of the individual. Evidence suggests that therapeutic interventions with repetitive motor training can aid in functional recovery of the paretic limb. Robotic rehabilitation may present an exercise intervention that can improve training and induce motor plasticity in individuals with stroke. An active (motorized) hand exoskeleton that provides support for wrist flexion/extension, abduction/adduction, pronation/supination, and finger pinch is integrated with a pre-existing 3-Degree of Freedom (DOF) haptic robot (Haptic Master, FCS Moog) to determine the efficacy of increased DOF during proximal and distal training in Upper Extremity (UE) rehabilitation. Subjects are randomly assigned into four groups to evaluate the significance of increased DOF during virtual training: Haptic Master control group (HM), Haptic Master with Gripper (HMG), Haptic Master with Wrist (HMW), and Haptic Master with Gripper and Wrist (HMWG). Each subject group performs a Pick and Place Task in a virtual environment where the distal hand exoskeleton is mapped to the virtual representation of the hand. Subjects are instructed to transport as many virtual cubes as possible to a specified target in the allotted time period of 120s. Three cube sizes are assessed to determine efficacy of the assistive end-effector. An additional virtual task, Mailbox Task, is performed to determine the effect of training and the ability to transfer skills between virtual settings in an unfamiliar environment. The effects of viewing mediums are also investigated to determine the effect of immersion on performance using an Oculus Rift as an HMD compared to conventional projection displays. It is hypothesized that individuals with both proximal and complete distal hand control (HMWG) will see increased benefit during the Pick and Place Task than individuals without the complete distal attachment, as assisted daily living tasks are often accomplished with coordinated arm and hand movement. The purpose of this study is to investigate the additive effect of increased degrees of freedom at the hand through task-specific training of the upper arm in a virtual environment, validate the ability to transfer skills obtained in a virtual environment to an untrained task, and determine the effects of viewing mediums on performance. A feasibility study is conducted in individuals with stroke to determine if the modular gripper can assist pinch movements. These investigations represent a comprehensive investigation to assess the potential benefits of assistive devices in a virtual reality setting to retrain lost function and increase efficacy in motor control in populations with motor impairments

Establishing Design Principles for Augmented Reality for Older Adults

Augmented Reality (AR) is growing rapidly and becoming a more mature and robust technology, which combines virtual information with the real environment in real-time. This becomes significant in ensuring the acceptance and success of Augmented Reality systems. With the growing number of older mobile phone users, evidence shows the possible trends associated with using AR systems to support older adults in terms of transportation, home activities, rehabilitation training and entertainment. However, there is a lack of research on a theoretical framework or AR design principles that could support designers when developing suitable AR applications for specific groups (e.g. older adults). This PhD research mainly focuses on the possibility of developing and applying AR design principles to provide various possible design alternatives in order to address the relevant AR-related issues focusing on older adults. This research firstly identified the architecture of Augmented Reality to understand the definition of AR using a range of previous AR examples. Secondly, AR design principles (version 1) were identified after describing the AR features and analysing the AR design recommendations. Thirdly, this research refined the AR design principles (version 2) by conducting two half-day focus groups with AR prototypes and related scenarios for older adults. The final version of the AR design principles (version 3) for older adults was established. These are: Instantaneous Augmentation, Layer-focus Augmentation, Modality-focus Augmentation, Accurate Augmentation and Hidden Reality. Ultimately, all of these design principles were applied to AR applications and examined in practice using two focus groups. Additionally, as part of the process of AR principle development, a number of AR issues were identified and categorised in terms of User, Device, Augmentation, Real Content, Interaction and Physical World, based on the pre-established AR architecture. These AR issues and design principles may help AR designers to explore quality design alternatives, which could potentially benefit older adults

Multimodal feedback cues on manual lifting in virtual environments

Improper manipulation of real-world objects increases the risk of developing work- related back injuries. In an effort to reduce such a risk and encourage appropriate lifting and moving methods, a Virtual Environment (VE) was employed. Virtual simulations can be used for ergonomic analysis. In this work, the VEs made use of multiple feedback techniques to allow a person to estimate the forces acting on their lower back. A person's head and hand movements were tracked in real-time whilst manipulating an object. A NIOSH lifting equation was used to calculate and determine the Lifting Index whereby the results were conveyed in real time. Visual display feedback techniques were designed and the effect of cues to enhance user performance was experimentally evaluated. The feedback cues provide the user with information about the forces acting on their lower back as they perform manual lifting tasks in VEs. Four different methods were compared and contrasted: No Feedback, Text, Colour and Combined Colour and Text. This work also investigated various types of auditory feedback technique to support object manipulation in VEs. Auditory feedback has been demonstrated to convey information in computer applications effectively, but little work has been reported on the efficacy of such techniques, particularly for ergonomic design. Four different methods were compared and contrasted: No Feedback, White-noise, Pitch and Tempo. A combined Audio-Visual (AV) technique was also examined by mixing both senses. The effect of Tactile Augmentation was also examined. Three different weights (real) were used and the results obtained by experiment were compared with the experiment using virtual weights in order to evaluate whether or not the presence of a real weighted object enhanced people's sense of realism. The goals of this study were to explore various senses of feedback technique (visual, auditory and tactile), compare the performance characteristics of each technique and understand their relative advantages and drawbacks.EThOS - Electronic Theses Online ServiceGBUnited Kingdo