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Context: When considering the use of Augmented Reality to provide navigation cues in a completely unknown environment, the content must be delivered into the environment with a repeatable level of accuracy such that the navigation cues can be understood and interpreted correctly by the user. Aims: This thesis aims to investigate whether a still image based reconstruction of an Augmented Reality environment can be used to develop a content delivery system that providers a repeatable level of accuracy for content placement. It will also investigate whether manipulation of the properties of a Spatial Marker object is sufficient to reduce object selection ambiguity in an Augmented Reality environment. Methods: A series of experiments were conducted to test the separate aspects of these aims. Participants were required to use the developed Keyframe Tagging tool to introduce virtual navigation markers into an Augmented Reality environment, and also to identify objects within an Augmented Reality environment that was signposted using different Virtual Spatial Markers. This tested the accuracy and repeatability of content placement of the approach, while also testing participants’ ability to reliably interpret virtual signposts within an Augmented Reality environment. Finally the Keyframe Tagging tool was tested by an expert user against a pre-existing solution to evaluate the time savings offered by this approach against the overall accuracy of content placement. Results: The average accuracy score for content placement across 20 participants was 64%, categorised as “Good” when compared with an expert benchmark result, while no tags were considered “incorrect” and only 8 from 200 tags were considered to have “Poor” accuracy, supporting the Keyframe Tagging approach. In terms of object identification from virtual cues, some of the predicted cognitive links between virtual marker property and target object did not surface, though participants reliably identified the correct objects across several trials. Conclusions: This thesis has demonstrated that accurate content delivery can be achieved through the use of a still image based reconstruction of an Augmented Reality environment. By using the Keyframe Tagging approach, content can be placed quickly and with a sufficient level of accuracy to demonstrate its utility in the scenarios outlined within this thesis. There are some observable limitations to the approach, which are discussed with the proposals for further work in this area.

The use of virtual reality in academic and industrial research has been rapidly expanding in recent years therefore evaluations of the quality and effectiveness of virtual environments are required. The assessment process is usually done through user evaluation that is being measured whilst the user engages with the system. The limitations of this method in terms of its variability and user bias of pre and post-experience have been recognised in the research literature. Therefore, there is a need to design more objective measures of system effectiveness that could complement subjective measures and provide a conceptual framework for the fidelity assessment in VR. There are many technological and perceptual factors that can influence the overall experience in virtual environments. The focus of this thesis was to investigate how multisensory feedback, provided during VR exposure, can modulate a user’s qualitative and quantitative experience in the virtual environment. In a series of experimental studies, the role of visual, audio, haptic and motion cues on objective and subjective evaluations of fidelity in VR was investigated. In all studies, objective measures of performance were collected and compared to the subjective measures of user perception. The results showed that the explicit evaluation of environmental and perceptual factors available within VR environments modulated user experience. In particular, the results shown that a user’s postural responses can be used as a basis for the objective measure of fidelity. Additionally, the role of augmented sensory cues was investigated during a manual assembly task. By recording and analysing the objective and subjective measures it was shown that augmented multisensory feedback modulated the user’s acceptability of the virtual environment in a positive manner and increased overall task performance. Furthermore, the presence of augmented cues mitigated the negative effects of inaccurate motion tracking and simulation sickness. In the follow up study, the beneficial effects of virtual training with augmented sensory cues were observed in the transfer of learning when the same task was performed in a real environment. Similarly, when the effects of 6 degrees of freedom motion cuing on user experience were investigated in a high fidelity flight simulator, the consistent findings between objective and subjective data were recorded. By measuring the pilot’s accuracy to follow the desired path during a slalom manoeuvre while perceived task demand was increased, it was shown that motion cuing is related to effective task performance and modulates the levels of workload, sickness and presence. The overall findings revealed that multisensory feedback plays an important role in the overall perception and fidelity evaluations of VR systems and as such user experience needs to be included when investigating the effectiveness of sensory feedback signals. Throughout this thesis it was consistently shown that subjective measures of user perception in VR are directly comparable to the objective measures of performance and therefore both should be used in order to obtain a robust results when investigating the effectiveness of VR systems. This conceptual framework can provide an effective method to study human perception, which can in turn provide a deeper understanding of the environmental and cognitive factors that can influence the overall user experience, in terms of fidelity requirements, in virtual reality environments.

This work aims to make the case for recognising the contributions of users to MMORPGs and Virtual Worlds. These environments are software entities which are protected in England and Wales by copyright. These online environments require input from numerous sources, including users, in order to retain their user base. Users therefore interact, create and develop these spaces with both in-game items such as characters, swords and clothing, and items developed outside of these environments. However, users frequently do not receive proprietary interests in any of these game items. The current paradigm of copyright and contract provides not just the framework for the allocation of claims to in-game items and the underlying software code, but also the governance constructs in these online environments. Contractual provisions are the dominant mechanisms of control, displacing automatically arising proprietary interests, and are required before any user can access an online game or Virtual World. It is argued that the current situation whereby contractual agreements restrict user claims whilst seeking to govern every aspect of MMORPGs and Virtual Worlds does not provide a 'fair' system for users, or their interests. It is concluded that End User License Agreements (EULAs) displace user rights whilst copyright and philosophical justifications indicate strong theoretical claims in support of users. As such, these EULAs ought to be considered in light of unfair contractual terms provisions to challenge the positions they adopt. There is a need to challenge the EULAs to validate the claims of users to items in online games and Virtual Worlds. This challenge must also indicate that there ought to be an appropriate governance system reflecting a balance between the interests of users and developers whilst providing a system whereby disputes between users, and over proprietary interests can be settled.

Virtual environments are increasingly being used for various applications. In recent times, with the advent of consumer grade systems, virtual reality has reached a critical mass and has exploded in terms of application domains. Extending from games and entertainment, VR is also applied in military training, remote surgery, flight simulation, co-operative work, and education. While all of these applications require careful design with respect to the interaction and aesthetics of the environment, they differ in their requirement of veridical realism: the impression of suspending disbelief to the point where perception in the environment is equal to the real world. At the same time, research in human centred disciplines have shown predictable biases and `errors' in perception with respect to the environment intended by the designer. This can be a challenge when certain perceptual phenomena prohibit the applicability of VR due to a discontinuation in what is rendered and what is actually perceived by the observer. This thesis is focused on a specific perceptual phenomenon in VR, namely that of distance compression, a term describing the widespread underestimation of distances that occur in VR relative to the real world. This perceptual anomaly occurs not only in visual based virtual environments, as compression has been observed and studied in auditory only and audiovisual spaces too. The contribution of this thesis is a novel technique for reducing compression, and its effectiveness is demonstrated in a series of empirical evaluations. First, research questions are synthesized from existing literature and the problem is introduced and explained through rigorous review of previous literature in the context of spatial audio, virtual reality technology, psychophysics, and multi-sensory integration. Second, the technique for reducing distance compression is proposed from an extensive literature review. Third, the technique is empirically tested through a series of studies involving human participants, virtual reality hardware, and bespoke software engineered for each study. Finally, the results from the studies are discussed and concluded with respect to the research questions proposed.

This thesis is concerned with interaction between people and virtual humans in the context of highly immersive virtual environments (VEs). Empirical studies have shown that virtual humans (agents) with even minimal behavioural capabilities can have a significant emotional impact on participants of immersive virtual environments (IVEs) to the extent that these have been used in studies of mental health issues such as social phobia and paranoia. This thesis focuses on understanding the impact on the responses of people to the behaviour of virtual humans rather than their visual appearance. There are three main research questions addressed. First, the thesis considers what are the key nonverbal behavioural cues used to portray a specific psychological state. Second, research determines the extent to which the underlying state of a virtual human is recognisable through the display of a key set of cues inferred from the behaviour of real humans. Finally, the degree to which a perceived psychological state in a virtual human invokes responses from participants in immersive virtual environments that are similar to those observed in the physical world is considered. These research questions were investigated through four experiments. The first experiment focused on the impact of visual fidelity and behavioural complexity on participant responses by implementing a model of gaze behaviour in virtual humans. The results of the study concluded that participants expected more life-like behaviours from more visually realistic virtual humans. The second experiment investigated the detrimental effects on participant responses when interacting with virtual humans with low behavioural complexity. The third experiment investigated the differences in responses of participants to virtual humans perceived to be in varying emotional states. The emotional states of the virtual humans were portrayed using postural and facial cues. Results indicated that posture does play an important role in the portrayal of affect however the behavioural model used in the study did not fully cover the qualities of body movement associated with the emotions studied. The final experiment focused on the portrayal of affect through the quality of body movement such as the speed of gestures. The effectiveness of the virtual humans was gauged through exploring a variety of participant responses including subjective responses, objective physiological and behavioural measures. The results show that participants are affected and respond to virtual humans in a significant manner provided that an appropriate behavioural model is used.

This thesis is concerned with methods for the effective design and analysis of the content of Virtual Environments (YEs) and documents and collates a range of research from within the field of Virtual Reality (VR) as well as earlier work in the field of methods integration for software engineering. First of all the nature of VR and certain problems specific to the design of YEs are discussed. The hypothesis of the thesis is then stated: to the effect that there is a need for a practical method for analysing, comparing and designing YEs across a range of delivery platforms, application domains and genres. In order to realise the demands of the hypothesis a content model for YEs is proposed - Perceptual Opportunities (POs) - and later expounded after a set of criteria to guide it have been developed. Having established the PO model it is then applied to the analysis of extant YEs and then extended to their comparative content analysis: this by way of verifying the practical utility of the model. Following this the ongoing experimental verification of the model in collaboration with psychologists is discussed. The discussions then move on to focus on the wider issues of VE design and design methodology and the role of POs in this context. At each stage of the exposition the POs are assessed in terms of the content criteria and the demands of the hypothesis. The conclusions focus on a number of current and potential applications and extensions of the PO theory and finish with a call for the establishment of a discipline of 'VR Theory' for which POs are intended as a stimulating factor

This Thesis develops methods that ultimately result in a self-contained Augmented Reality hand- held system for assisting a user to interactively build 3D wireframe computer models of real objects. The approach is based on an in-situ (in-place) interactive image-based model build- ing method that allows users to build or import models useful to perform augmentations in most places. Three main components are studied: a number of visual competences such as 6D tracking and object detection methods, user interaction techniques, and evaluations for handheld devices. Four visual-based tracking algorithms have been implemented, tested and discussed in the context of existing literature. Two of them are region-based tracking algorithms that are tracking with general regression and sum-of-squared differences tracking algorithms. The others are edge- based tracking algorithms which are contour and 3D model-based tracking algorithms Based on testing, the 3D model-based tracking algorithm has been selected to be used for the rest of the system. Two types of input devices, which are a one-handed wand-like (WnD) and a two-handed touch- screen (TS), for users to interact with the system have been custom built and studied. Two methods for users to define a free 3D vertex from 2D images have been investigated. The user studies were carried out with the two different hardware platforms (WnD and TS), two different 3D selection techniques (two-click (2Cs) and click-and-move (CnM) techniques) and two different trackers (model-based and SLAM-based trackers). There were two groups of participants involved in the studies. The first group performed the experiment by using the system that estimates a camera pose from the model-based tracker. The statistical results suggested that the WnD combined with . 2Cs is the best system for 3D vertex selection, and overall participants had a marginal preference for the WnD combined with CnM over the WnD combined with 2Cs. The system that estimates the camera pose from the SLAM-based tracker was used in the second study. This aimed to con- sider cases when it is possible to afford to maintain a larger model (or map) of the immediate environment. Although the statistical results of this study are similar to the results of the first study, overall participants had a marginal preference for the WnD combined with 2Cs over the WnD combined with CnM. An integrated in-situ modelling system named OutlinAR and its implementation are introduced. It consists of the visual tracking algorithms, the user interactive techniques and hardware platforms. To make the OutlinAR easier to use, a novel technique of edge-based object detection used to re-initialise the tracker has been eo-developed and integrated into the system. The detector works form a library of edgelet constellations of object's images recovered at a training phase. During the detection stage, the detector will detect the object by matching edgelet constellations to those in the library. To summarize the potential of the work, the touch screen version of OutlinAR has been ported to run on a mobile phone, demonstrating all the stages necessary for modelling and using wireframe models for Augmented Reality on the go.

Virtual Reality (VR) is a powerful tool for visualising and interacting with information. VR is inherently 3D whereas the majority of VR authoring tools are 2D. Many of the resources we use to judge 3D form and appearance, like stereopsis, focus and judgement with respect to one's own body, are not available to us when using 2D technology. While 2D solutions usually provide a reasonable representation of 3D, what looks plausible in 2D can be incorrect or impossible to achieve when studied in 3D; an example of this is artwork by Escher. Additionally, the amount of effort and expertise required to create useful Virtual Environments (VEs) limits the use of the technology to small and specific user groups. Research is held back because of these limitations. Although VR provides potential solutions to current issues in research, visualising and interacting within complex data or performing repeatable experiences of an environment for different users for example; academics from other fields are not applying their research domain to this technology because of the cost, time and expertise required to use VR effectively. There is currently a skills bottleneck with VR technology. This thesis aims to alleviate this bottleneck and provide a springboard for other science by creating a usable immersive VE authoring tool named VRIDE. A literature survey confirmed this need and lack of such tools as well as the importance of UI/GUI and the need for and lack of software libraries capable of providing this functionality to programmers for creating immersive VR applications. Usability tests document participant's perception of their own mental and physical effort using VRIDE; task performance and behavioural analysis from videos are also reported. This data is compared to determine the overall performance of VRIDE. It is concluded that VRIDE and its associated 3DGUI development library provide a solid springboard for both novice and expert users wishing to use VR technology.

The advances in Virtual Environments (VE) technology have further enhanced the capabilities of digital models, allowing teams of engineers to analyse designs interactively to ensure the ease of maintenance. If a VE interface is required to satisfy engineers' realistic needs, the interaction techniques must be carried out with a satisfactory level of naturalness and directness. Realistic direct manipulation within VE in this thesis implies that the users are able to use their own hands to directly interact upon the 3D virtual objects to perform bimanual operations (in both symmetric and asymmetric scenario). In this thesis, CAVE-based VE was chosen as the environment for the users to interact with the advanced stereoscopic 3D images of virtual objects.