Reversible and imperceptible watermarking is recognized as a robust approach to confirm the integrity and authenticity of medical images and to verify that alterations can be detected and tracked back. In this paper, a novel blind reversible watermarking approach is presented to detect intentional and unintentional changes within brain Magnetic Resonance (MR) images. The scheme segments images into two parts; the Region of Interest (ROI) and the Region of Non Interest (RONI). Watermark data is encoded into the ROI using reversible watermarking based on the Difference Expansion (DE) technique. Experimental results show that the proposed method, whilst fully reversible, can also realize a watermarked image with low degradation for reasonable and controllable embedding capacity. This is fulfilled by concealing the data into ‘smooth’ regions inside the ROI and through the elimination of the large location map required for extracting the watermark and retrieving the original image. Our scheme delivers highly imperceptible watermarked images, at 92.18–99.94 dB Peak Signal to Noise Ratio (PSNR) evaluated through implementing a clinical trial based on relative Visual Grading Analysis (relative VGA). This trial defines the level of modification that can be applied to medical images without perceptual distortion. This compares favorably to outcomes reported under current state-of-art techniques. Integrity and authenticity of medical images are also ensured through detecting subsequent changes enacted on the watermarked images. This enhanced security measure, therefore, enables the detection of image manipulations, by an imperceptible approach, that may establish increased trust in the digital medical workflow.

In today's society where we live in a world of constant connectivity, many people are now looking to cloud services in order to store their files so they can have access to them wherever they are. By using cloud services, users can access files anywhere with an internet connection. However, while cloud storage is convenient, it also presents security risks. From a forensics perspective, the increasing popularity of cloud storage platforms, makes investigation into such exploits much more difficult, especially since many platforms such as mobile devices as well as computers are able to use these services. This paper presents investigation of hubiC as one of popular cloud platforms running on Microsoft Windows 8.1. Remaining artefacts pertaining different usage of hubiC namely upload, download, installation and uninstallation on Microsoft Windows 8.1 are presented.

The aim of our experiment is to determine if eye-gaze can be estimated from a virtuality human: to within the accuracies that underpin social interaction; and reliably across gaze poses and camera arrangements likely in every day settings. The scene is set by explaining why Immersive Virtuality Telepresence has the potential to meet the grand challenge of faithfully communicating both the appearance and the focus of attention of a remote human participant within a shared 3D computer-supported context. Within the experiment n=22 participants rotated static 3D virtuality humans, reconstructed from surround images, until they felt most looked at. The dependent variable was absolute angular error, which was compared to that underpinning social gaze behaviour in the natural world. Independent variables were 1) relative orientations of eye, head and body of captured subject; and 2) subset of cameras used to texture the form. Analysis looked for statistical and practical significance and qualitative corroborating evidence. The analysed results tell us much about the importance and detail of the relationship between gaze pose, method of video based reconstruction, and camera arrangement. They tell us that virtuality can reproduce gaze to an accuracy useful in social interaction, but with the adopted method of Video Based Reconstruction, this is highly dependent on combination of gaze pose and camera arrangement. This suggests changes in the VBR approach in order to allow more flexible camera arrangements. The work is of interest to those wanting to support expressive meetings that are both socially and spatially situated, and particular those using or building Immersive Virtuality Telepresence to accomplish this. It is also of relevance to the use of virtuality humans in applications ranging from the study of human interactions to gaming and the crossing of the stage line in films and TV.

This paper reports a GPU based, projective texturing approach to reconstructing the human form, from multiple images, at a quality and frame rate close to high end video conferencing. The ultimate aim is to support spatially grounded, non-verbal communication through a video based medium. This will, we hope, enable us to balance image quality and update rate to deliver highly realistic and dynamic 3D human representations that offer the visual quality of high end video conferencing with the spatial and temporal characteristics of immersive virtual environments. The output of this will enhance communication by enabling a remote actor to be realistically projected into another person's local space, projected into an extension of the local space, or projected into a shared virtual space. This extends previous work by incorporating texture into the reconstructed form and evaluating the optimized process within our established simulation system.

What level of synchronization is necessary between images from multiple cameras in order to realistically reconstruct a moving human in 3D? Live reconstruction of the human form, from cameras surrounding the subject, could bridge the gap between video conferencing and Immersive Collaborative Virtual Environments (ICVEs). Video conferencing faithfully reproduces what someone looks like whereas ICVE faithfully reproduces what they look at. While 3D video has been demonstrated in tele-immersion prototypes, the visual/temporal quality has been way below what has become acceptable in video conferencing. Managed synchronization of the acquisition stage is universally used today to ensure multiple images feeding the reconstruction algorithm were taken at the same time. However, this inevitably increases latency and jitter. We measure the temporal characteristics of the capture stage and the impact of inconsistency on the reconstruction algorithm this feeds. This gives us both input and output characteristics for synchronization. From this we determine whether frame synchronization of multiple camera video streams actually needs to be delivered for 3D reconstruction, and if not what level of temporal divergence is acceptable across the captured image frames.

Effective processing of source data matched to appropriate visualisation can greatly enhance the user's ability to explore and comprehend complex information. While this is a fundamental problem for many domains, in medical applications it is particularly important. None-invasive scanning technologies, such as MRI, have greatly enhanced our ability to `image' the internal body, however the resultant visualisation is often difficult to comprehend due to both inadequacies in the scanning process and sub-optimal approaches to visualisation and data representation. These factors impose significant cognitive load on the user, requiring skill and experience to accurately comprehend detail and intense concentration, and in less experienced users, to understand the structures present. Our broader research aims to identify whether 3D representations of MRI data sets offer a more intuitive means of viewing the data and thereby enable easier understanding and comprehension of the scanned body region. As part of this research we have constructed a 3D MRI viewing application, raaMediVol, which utilises recent developments in 3D computer graphics hardware, to present an interactive environment that enables the user to view both traditional 2D slice representations and an enhanced 3D volumetric form that is freely explorable and configurable both on traditional 2D computer desktop displays and within immersive projection technologies (IPTs)[1]. Initial evaluation of the two representational paradigms been undertaken through the comparative assessment of experienced clinicians' performance in diagnosing a range of soft tissue pathologies within the shoulder, displayed in both traditional 2D slice, and evolved 3D volumetric representational form. An overview of the application, its technical operation, and the results of the evaluation trials are presented.

Eye gaze is an important and widely studied non-verbal resource in co-located social interaction. When we attempt to support tele-presence between people, there are two main technologies that can be used today: video-conferencing (VC) and collaborative virtual environments (CVEs). In VC, one can observe eye-gaze behaviour but practically the targets of eye-gaze are only correct if the participants remain relatively still. We attempt to support eye-gaze behaviour in an unconstrained manner by integrating eye-trackers into an Immersive CVE (ICVE) system. This paper aims to show that while both ICVE and VC allow people to discern being looked at and what else is looked at, when someone gazes into their space from another location, ICVE alone can continue to do this as people move. The conditions of aligned VC, ICVE, eye-gaze enabled ICVE and co-location are compared. The impact of factors of alignment, lighting, resolution, and perspective distortion are minimised through a set of pilot experiments, before a formal experiment records results for optimal settings. Results show that both VC and ICVE support eye-gaze in constrained situations, but only ICVE supports movement of the observer. We quantify the mis-judgements that are made and discuss how our findings might inform research into supporting eye-gaze through interpolated free viewpoint video based methods.

None-invasive scanning technologies, such as MRI, have greatly enhanced our ability to ‘image’ the internal body, however the resultant visualisation is often difficult to comprehend due to both inadequacies in the scanning process and sub-optimal approaches to visualisation and data representation. These factors impose significant cognitive load on the user, requiring skill and experience to accurately comprehend the detail of the data, and intense concentration, in less experienced users, to understand the structures present. This research aims to improve the users’ ability to comprehend and explore the scanned data sets, through a combination of enhanced data processing and effective 3D visualisation that will seek refined representational paradigms to intuitively convey meaning to the user. This is achieved in a real-time 3D exploration environment, utilising recent developments in graphics hardware, which enables the user to both refine the visual representation and effectively explore the data set, thereby defining a prototype for enhanced medical visualisation and exploration. Ultimately this will improve diagnosis, procedural planning and most importantly communication, both between medical clinicians and the patient themselves.

This research presents and evaluates a CAVE-like IPT system in which a tracked display and interaction device (TDID), based on a tablet PC, is used to display an augmented viewing system for detailed examination of a close focused objects. This maintains wider context, displayed on the IPT display environment, thereby enabling effective wayfinding and navigation, while still enabling detailed examination of the region of interest on a position sensitive high-resolution display (TDID). Evaluation against an un- augmented CAVE-like IPT system, demonstrates the effectiveness of this approach in enabling users to both explore around the model effectively resolve fine detail.

CAVE-like Immersive Projection Technologies (IPT) systems have long been used to explore complex 3D geometric data sets. While this approach works well for many activity types, there are a class of activities that remain challenging within these environments. When virtual objects are brought into close proximity to the user (denoted by a virtual distance of less than that between the user and the projection surface) the users inability to perceive fine detail and effectively explore around an object from an inward looking perspective becomes apparent. This research presents and evaluates the introduction of an augmented viewing device into a traditional CAVE-like IPT system. This has been accomplished by integrating a tracked tablet PC device that offers a multi modal interface for both user position referenced micro/macroscopic viewing and alternate interaction inputs as part of a distributed augmented CAVE-like IPT system.

Interactive 3D visualization is increasingly used for design/review activities in urban planning and construction. However, as this becomes more wide spread user expectations of the levels of interaction and the functionality expand. Many organizations maintain rich sources of information describing the urban environment and society, supported by a distributed set of services that provide functionality. These resources present an opportunity to create new design/review environments in which groups of stakeholders may collaborate to explore and evaluate new solutions. However, using this distributed functionality and information presents new challenges in defining and managing the content of interactive de sign/review visual environments. This paper presents a novel system for multi-user co-located interaction by which a group of users, viewing a common 3D visualization, are provided with collaborative interaction through a set of distributed personal interfaces. A fundamental part of this activity is the formation of a unified, distributable model that references distributed content, and the available functionality related services provide

Human-to-human interaction across distributed applications requires that sufficient consistency be maintained among participants in the face of network characteristics such as latency and limited bandwidth. Techniques and approaches for reducing bandwidth usage can minimize network delays by reducing the network traffic and therefore better exploiting available bandwidth. However, these approaches induce inconsistencies within the level of human perception. Dead reckoning is a well-known technique for reducing the number of update packets transmitted between participating nodes. It employs a distance threshold for deciding when to generate update packets. This paper questions the use of such a distance threshold in the context of absolute consistency and it highlights a major drawback with such a technique. An alternative threshold criterion based on time and distance is examined and it is compared to the distance only threshold. A drawback with this proposed technique is also identified and a hybrid threshold criterion is then proposed. However, the trade-off between spatial and temporal inconsistency remains.