Nicholaos Mourkoussis

ARCO - an architecture for digitization, management and presentation of virtual exhibitions

A complete tool chain starting with stereo photogrammetry based digitization of artefacts, their refinement, collection and management with other multimedia data, and visualization using virtual and augmented reality is presented. Our system provides a one-stop-solution for museums to create, manage and present both content and context for virtual exhibitions. Interoperability and standards are also key features of our system allowing both small and large museums to build a bespoke system suited to their needs

Metadata requirements for digital museum environments

We describe a system which addresses all the processes involved in digitally acquiring, modelling, storing, manipulating and creating virtual exhibitions from 3D museum artefacts. More specifically, we examine the significance of metadata in enabling and supporting all of these processes and describe the extensive facilities provided for authoring, maintaining and managing metadata. The development of the system has been heavily influenced by factors relating to interoperability, standards, museum best practice and feedback from two museum pilot sites. Finally, we briefly consider the system in the wider context of applications such as virtual learning environments and distributed repositories of archives.

An interactive visualisation interface for virtual museums

Cultural institutions, such as museums are particularly interested in making their collections accessible to people with physical disabilities. New technologies, such as Web3D and augmented reality (AR) can aid museums to respond to this challenge by building virtual museums accessible over the Internet or through kiosks located in accessible places within the museum. In this paper, we propose a prototype user-friendly visualisation interface that uses Web3D and AR techniques to visualise cultural heritage artefacts for virtual museum exhibitions. User interactions within the virtual museum are performed in an effective way with the help of assistive technology, so that users can feel completely related with the virtual museum artefacts and so benefit in terms of education and entertainment.

Quantifying fidelity for virtual environment simulations employing memory schema assumptions

In a virtual environment (VE), efficient techniques are often needed to economize on rendering computation without compromising the information transmitted. The reported experiments devise a functional fidelity metric by exploiting research on memory schemata. According to the proposed measure, similar information would be transmitted across synthetic and real-world scenes depicting a specific schema. This would ultimately indicate which areas in a VE could be rendered in lower quality without affecting information uptake. We examine whether computationally more expensive scenes of greater visual fidelity affect memory performance after exposure to immersive VEs, or whether they are merely more aesthetically pleasing than their diminished visual quality counterparts. Results indicate that memory schemata function in VEs similar to real-world environments. “High-level” visual cognition related to late visual processing is unaffected by ubiquitous graphics manipulations such as polygon count and depth of shadow rendering; “normal” cognition operates as long as the scenes look acceptably realistic. However, when the overall realism of the scene is greatly reduced, such as in wireframe, then visual cognition becomes abnormal. Effects that distinguish schema-consistent from schema-inconsistent objects change because the whole scene now looks incongruent. We have shown that this effect is not due to a failure of basic recognition.

A schema-based selective rendering framework

Perception principles have been incorporated into rendering algorithms in order to optimize rendering computation and produce photorealistic images from a human rather than a machine point of view. In order to economize on rendering computation, selective rendering guides high level of detail to specific regions of a synthetic scene and lower quality to the remaining scene, without compromising the level of information transmitted. Scene regions that have been rendered in low and high quality can be combined to form one complete scene. Such decisions are guided by predictive attention modeling, gaze or task-based information. We propose a novel selective rendering approach which is task and gaze-independent, simulating cognitive creation of spatial hypotheses. Scene objects are rendered in varying polygon quality according to how they are associated with the context (schema) of the scene. Experimental studies in synthetic scenes have revealed that consistent objects which are expected to be found in a scene can be rendered in lower quality without affecting information uptake. Exploiting such expectations, inconsistent items which are salient require a high level of rendering detail in order for them to be perceptually acknowledged. The contribution of this paper is an innovative x3D-based selective rendering framework based on memory schemas and implemented through metadata enrichment.

ARCOLite-an XML based system for building and presenting virtual museum exhibitions using Web3D and augmented reality

This paper describes ARCOLite, our low cost XML based client-server architecture for building and presenting digital heritage content in virtual museums. Our system includes components for creation and refinement of virtual artefacts including virtual reconstruction of buildings; XML content management, XML technologies for content repositories and presentation; and content visualisation using Web3D, virtual and augmented reality

Selective rendering based on perceptual importance of scene regions

Computer graphics algorithms have for long dealt with simulation of physics: simulation of the geometry of a real-world space, simulation of the light propagation in a real environment and simulation of motor actions with appropriate tracking. Perception principles have subsequently been incorporated into rendering algorithms in order to save rendering computation and produce photo realistic images from a human rather than a machine point of view. Spatial memory tasks are often incorporated in benchmarking processes when assessing fidelity of a VE simulation, since spatial awareness is crucial for human performance efficiency of any task that entails awareness of space. This paper is exploring the exploitation of visual perception principles towards efficient selective rendering techniques. In order to economize on rendering computation, selective rendering guides a high level of detail to appropriate regions of a synthetic scene. Such decisions are based on predictive attention modeling, gaze or even cognitive information. Experimental studies presented will show that it is possible to produce scenes from a human rather than a physics point of view.

A selective rendering algorithm based on memory schemas

In order to economize on rendering computation, selective rendering guides high level of detail to specific regions of a synthetic scene and lower quality to the remaining scene, without compromising the level of information transmitted. Scene regions that have been rendered in low and high quality can be combined to form one complete scene. We propose a novel selective rendering approach which is task and gaze-independent, simulating cognitive creation of spatial hypotheses. Scene objects are rendered in varying quality (polygon count) according to how they are associated with the context (schema) of the scene.

Action-based slant perception in real and virtual environments

An innovative action-based motoric measure of slant is proposed, based on gait. This measure is ecologically-valid derived from the angle that the foot makes in relation to the horizontal ground plane immediately before impact (Figure 1). This work explores whether the proposed measure is affected by factors such as material of the walking surface and inclination of the walking ramps. Moreover, experimental studies were conducted in a real environment set-up and in its virtual counterpart. Comparisons between real-world spatial judgments and simulation equivalents provide performance benchmarks as well as tools to assess whether a technological set-up would be of similar functional fidelity to a real-world task situation.

Friction and slant perception in real and virtual environments

Comparisons between real-world spatial judgments and simulation equivalents provide performance benchmarks as well as tools to assess whether a technological set-up would be of similar functional fidelity to a real-world task situation. It is widely recognised that perceptual fidelity is not necessarily equivalent to physical simulation. Identifying ways to ‘induce’ reality by possibly distorting physics based on fundamental perceptual processes triggered in real and synthetic worlds rather than simulating the physics of reality is a novel research route worth pursuing. We describe a set of comparative studies between a real-world task situation and varied synthetic simulations which attempt to introduce novel functional fidelity metrics based on slant and friction perception, as well as novel perceptual estimates of slant offering a truly interdisciplinary approach.