Realistic Rendering of Augmented Reality Heritage Exhibitions CyberEmathy8/2014

CyberEmpathy – Visual and Media Studies Academic Journal

ISSUE 8/2014: Augmented Reality Studies

Abstract:

The preservation of cultural heritage is a key concern for museums

and other cultural heritage institutions. Another important issue is

the limited space available to exhibit their collections to their

visitors. Although a number of experimental systems based on

advanced information and communication technologies such as

Web3D, virtual reality and augmented reality have been previously

developed they have not really managed to become popular mainly

because they were used for passive viewing and limited interaction.

This paper presents how realistic augmented reality kiosk

exhibitions of museum collections, including galleries and artefacts,

can be developed so that they can attract the visitor’s attention.

Advanced computer graphics rendering algorithms such as

interactive lighting and shading, fake, soft and hard shadows as well

as reflections are combined with a high-level augmented reality

tangible interface presented in real-time performance.

FOTIS LIAROKAPIS Director of Interactive Worlds Applied Research Group (iWARG), Faculty of Engineering and Computing at Coventry University and a research fellow at the Serious Games Institute.

FOTIS LIAROKAPIS

1. Realistic Rendering of Augmented Reality Heritage Exhibitions

Realistic Rendering of Augmented Reality Heritage Exhibitions / F.Liarokapis. CyberEmpathy: Visual Communication and New Media in Art, Science, Humanities, Design and Technology. ISSUE 8 /2014. Augmented Reality Studies. ISSN 2299-906X. Kokazone. Mode of access: Internet via World Wide Web.



Introduction

The majority of heritage institutions such as museums and art galleries has realised

that Information and Communication Technologies (ICTs) have the potential, if used

properly, to attract a large number of visitors and promote their exhibits in a better

way. Each institution makes different use of ICT technologies depending on its needs,

resulting in variety in the presentation and interaction styles available. For example,

most museums and art galleries have invested on touch-screen displays with simple

representations as the main presentation medium without investigating the

capabilities of more advanced ICT such as augmented reality (AR). Also, a number of

pilot projects have been developed by universities but their results were largely

disappointing [Arn00]. Part of the problem lies on the isolation or lack of

communication between heritage institutions and universities as well as on the

diversity of the technologies used.

Open standards such as XML, VRML and Web3D, as well as computer graphics

techniques seem to have clear benefits to assist archaeologists in their professional

work [Arn00], [WM*04] and attract the visitor’s attention. In particular, 3D

archaeological reconstruction techniques have demonstrated impressive results

focusing on the fine detail and high level of realism. Based on these accurate and

realistic 3D representations, a number of virtual museum exhibitions have been

developed [SL*05]. The concept of AR exhibitions has been around for a few years

now and researchers have designed a number of prototypes [BA*99], [Gat00],

[HC*01], allowing for more advanced representations (i.e. table-top AR exhibitions)

and interaction (i.e. natural techniques). An overview of the most significant work in

virtual and augmented museum exhibitions has been previously documented

[SL*05].

In addition, Huang et al (2005) developed a tangible photorealistic virtual museum

system that allows visitors to interact naturally and have an immersive experience

with museum exhibits [HCC05]. The ARCO project has developed realistic virtual

and augmented presentations of museum galleries and their exhibits through the use

of tangible AR interfaces [WM*04], [LS*04]. Another interesting approach is the

Virtual Showcase which is a projection-based AR display system [BF*01]. The Virtual



Showcase contains real scientific and cultural artefacts allowing their 3D graphical

augmentation. The virtual part of the showcase can react in various ways to a visitor,

which provides the possibility for intuitive interaction with the displayed content.

However, all of the above prototypes ‘suffer’ from advanced realistic rendering

techniques. Realism was achieved only through 3D reconstruction techniques

resulting in AR exhibitions that give a distant feeling to the visitors. The aim of this

work is to provide a list of advanced rendering techniques and illustrate how to

develop realistic AR kiosk exhibitions of museum collections, including galleries and

artefacts in order to attract the visitor’s attention. Based on previous prototypes

[LS*04], [Lia07], a number of realistic techniques such as generation of interactive

lighting, shading and transparency. Section 4, presents a methodology for generating

fake, hard and soft shadows whereas section 5, illustrates how to generate

environmental and planar reflections. Finally section 6, presents conclusions and

future work.

2. Requirements for AR Kiosk Exhibitions

Museums and other heritage exhibitions need to exhibit their collections with the aim

of educating and entertaining their visitors [MK*97]. However, they usually contain

large collections of artefacts and information presented in different locations

[BB*01]. One of the most challenging objectives is the preservation of our history and

culture, in respect to time and place. To achieve this, two conditions must happen:

the 3D representation must be accurate and the presentation realistic. Moreover, the

input of archaeologists and museum curators is necessary to define the AR

presentation style in terms of the user as well as the museum requirements. In

particular, they should know the attractiveness of each artefact and the usefulness of

the labels [BS95]. On the other hand, from the visitor’s perspective, they require

immediate, realistic and easy access to the AR information in real-time performance.

It is important for them to feel related with the augmented information as it is part of

the real environment. Technically speaking, the most important requirements



concerning the effectiveness of an AR exhibition relate to the quality of visualisation

and interaction techniques. Effective interaction techniques for indoor AR

environment have been previously presented [Lia07] and apart from them, the

success of a kiosk exhibition is highly related to the level of realism achieved.

Properties of the real world such as lighting, shading, shadows and reflections must

be therefore reflected to the AR kiosk exhibition.

3. Realistic Augmentation

Realistic augmentation is an issue of high importance for the AR interface system.

The major focus was to realistically augment 3D heritage scenes. To increase the

realism of the AR scene, artificial lighting was carefully integrated. The precise

manipulation of the light sources allowed for the generation of real-time shadows and

reflections. Other effects implemented to enhance realism, such as atmospheric

effects and transparency, were necessary for simulating reality. 3.1. Interactive

Lighting and Shading 3D modelling techniques have advanced to a great extend so

that the common illumination model can be predetermined and saved in a specific

computer graphics file format (i.e. 3ds, VRML). Thus, realism is an issue that is

highly dependent on modelling capabilities. In cases where the illumination model is

not pre-computed an approximation model can be used. The real world is comprised

of objects that have different characteristics. For example, some objects are extremely

shiny whereas others are not. To succeed in realistic AR rendering, the common

illumination model has to be controlled interactively. During recent years much

research work has been performed in this field [LDR00][DRB97]. The biggest

problem is to automatically match the virtual lighting information with the real

world. In this work, this is done based on user-input by controlling the position and

characteristics of the light(s) in the AR environment. To estimate the lighting model

OpenGL’s lighting model is addressed because it is one of the industry’s standard and

can easily produce quite impressive results. This model divides lighting into four

independent components: ambient, diffuse, specular and emissive. Light sources in



OpenGL have several properties including colour, position and direction. To light the

virtual scene more, multiple light sources can be added to the environment. The

equation used for the entire calculation in RGBA mode [SW*99] is presented below:

where Vc is the colour of each vertex, em is the emission of the material, αl is the

ambient light model, αm is the ambient material, αterm is the ambient term, dterm is

the diffusion term and sterm is the specular term. Shading is used for determining

the pixels’ colour based on lighting computations [Mol99]. There are three basic

types of shading including flat, smooth and phong shading [SW*99]. In flat shading

the colour of one particular vertex is duplicated across all the primitive vertices. This

method is very simple and works very fast but it does not give a smooth appearance

to curved surfaces because all pixels in the polygon as shaded the same. On the other

hand, smooth shading, also known as Gouraud shading, is one of the most popular

shading algorithms which interpolates light intensities across the face of a polygon

using values taken from its vertices [Mol99]. Gouraud shading is slower than flat

shading but it produces a smoother appearance across polygons as presented in

Figure 1.

Figure 1: Shading modes in AR (a) flat (top view) (b) smooth (bottom view)



Phong shading interpolates the normals across each polygon instead of interpolating

the vertex intensities as performed in smooth shading. Although phong shading

produces smoother results, it has the drawback of having greater computational cost

and usually is performed off-line [Ang03]. It is worth-mentioning that shading is

more appropriate when the virtual artefacts do not include any texturing information.

3.2. Transparency

The real world is composed of three types of objects: transparent, translucent and

opaque objects. The most popular method for adding transparency information for

translucent objects is alpha blending. Alpha blending is generated by rendering

polygons through a predefined mask whose density is proportional to the

transparency of the object. When the transparency effect is applied successfully, the

resultant colour of a pixel is a combination of the foreground and background colour.

The general equation for alpha, which has a normalized value of 0 to 1 for each colour

pixel, is illustrated below:

where α is the opacity of the surface, pAx,y is the colour of the pixel A and pBx,y is the

colour of the pixel B. Instead of using ray-tracing rendering, opacity can be used

instead [Ang03]. This method is based on the control of the alpha channel (α) of the

colour mode (RGBA). More specific, when blending is performed, the value of alpha

channel determines the value of each of the red, green and blue (RGB) components.

The amount of light that penetrates through surfaces is called opacity. When the

opacity of a surface is zero then the surface is transparent. The transparency of a

surface can be calculated by the following formula:



where tsurface is the transparency of the surface of the object. In AR environments,

transparency is an effect that can be applied very successfully in some types of

applications or scenarios [BNB05], [Lia07]. The 3D models used must be created in

such a way so that they contain transparent surfaces. Therefore, the rendering part,

transparent objects is achieved through the alpha blending mechanism.

Figure 2: Transparency levels in AR (a) less transparent (80% alpha blending) (b) more transparent (20% alpha blending)

Figure 2 shows the same textured object with different levels of transparency. Figure

2, (a), shows a 3D artefact with the alpha value close to unity (80% or 0.8) blending

while in Figure 2, (b) presents the same 3D artefact with alpha value close to zero

(20% or 0.2) blending. This effect is very useful when occluding virtual artefacts are

overlaid in a kiosk environment. Similarly, to commercial video games, using

transparency it is possible to make the virtual artefact that occludes the others so that

all artefacts are visible. In addition, transparency can be very successfully applied for

achieving other visualisation effects such as reflections (see section 5).

3.3. Atmospheric Effects

Special effects are an area of continuing research and development. The

entertainment industry (films and games mainly) has made many advances during

the last years. Fog is an existing 3D computer graphics effect that can be used to



create the illusion of partially transparent space between the camera and the 3D

object. This can be easily achieved by blending in the environment, a distance

dependent colour that is defined as fog factor f [Ang03]. Using an atmosphere

intensity attenuation function the rendered information can be simulated through a

hazy or smoky atmosphere [Bea04].The three most popular types of fog densities

are:linear, exponential and Gaussian. The equations usedfor the different variations

of the fog effect areillustrated following [SW*99]:

where z is the camera’s coordinate distance between the viewpoint and the fragment

centre and end and start are specified as the boundary limits correspondingly. Fog

can be generated by blending a RGB fog colour with one of the above blending

factors.

4. Shadow Generation

Shadows play a very important role for the generation of a realistic AR kiosk

environment. In reality, all artefacts have their shadows so virtual artefacts should

have as well. Two of the most important shadow algorithms [Mol99] can be

distinguished in two types: planar and curved surface shadows.



4.1. Planar and Curved Surfaces Shadows

Planar shadows are the simplest case of shadowing into planar surfaces. Hard

shadows may be generated using only point light sources but to create soft shadows

then area light sources have to be used. In the real world, shadows consist of a fully

shaded region, called the umbra and a partially shadowed area, called the penumbra

[Vin95] as illustrated in Figure 3.

Figure 3: Shadow generation

A way to simulate soft shadows is to use the shadow map algorithm. In general, soft

shadows are preferred because the soft edges make the user aware that the shadow is

indeed a shadow. On the other hand, hard- edged shadows can be confusing and give

the illusion of actual geometric features. Shadows projected on curved surfaces are

considered to be an extension of planar shadows. Finally, another popular solution is

to use a generated shadow image as a projective texture [Mol99].



4.2. Fake Shadows

Fake shadows are very easy to generate and even if they are blurred or inaccurate,

they can give an estimation of the depth [Mol99]. The easiest was to implement fake

shadows is to project a 3D shape, which is similar to the rendered object, on the

ground and the paint it black. In most of the applications, a simple geometrical shape

is usually enough. Although the most popular shape is the sphere, other shapes can

produce quite effective results such as the torus as illustrated in Figure 4.

Figure 4: Fake shadow generation using (a) Torus (left view) (b) Sphere (right view)

On both images of Figure 4, a virtual torus is superimposed on a marker card but

different fake shadows are projected onto the ground. The fake shadow presented in

Figure 4, (a) is represented using a torus while in Figure 4, (b) the shadow is

represented using a sphere. The difference between these two types is on the

appearance of the virtual shadow. The sphere produces much smoother results but

this is not always the case. Other geometrical shapes that have been experimentally

tested include the square, the cube, the cone, the pyramid and the teapot. Although

this type of shadows is sufficient for some applications, it cannot be used in cases

where realism is an important factor. To realize a more realistic augmentation, more

advanced shadowing techniques are required, such as planar shadows.



4.3. Planar Shadows

Realistic shadows are quite difficult to implement in real-time [Vin95] but planar

projection shadows can produce very nice effects without having to account for the

generation of soft shadows. Even if there are many algorithms for generating shadow

algorithms like ray- tracing, projection, shadow volumes and shadow maps [AT*01]

this work concentrates on a general solution for shadows projected onto a kiosk

presentation environment.

Figure 5: Planar shadow projection

As illustrated in Figure 5, the location of the shadow can be calculated by projecting

all the vertices of the AR object to the direction of the light source. To generate

augmented shadows an algorithm that creates a 4x4 projection matrix, Ps, in

homogeneous coordinates must be calculated based only on the plane equation

coefficients and the position of the light [Mol99]. Say that L is the position of the

point light source; P the position of a vertex of the AR artefact where the shadow is

cast; and n the normal vector of the plane (Figure 6).] below:



Figure 6: Calculation of the shadow projection

As a first step, a plane needs to be expressed as:

where S is the location of a point of the plane. Next the straight that passes from the

plane point in the direction of the light source is defined by the equation of a straight

line: the equation [Wat99] below:

Solving for γ and substituting into the above equations, the shadow projected point,

P’, contains the correct projection as shown below:



In order to turn this into a matrix, it is necessary to follow the projection matrix

convention below:

Based on the above equation, the transpose of the projection matrix that calculates

the shadow [MB99] is illustrated below:

where Lp•Pc is the dot product of plane and light position. The projection matrix has

a number of advantages compared with other methods such as fake shadows. The

most important is that it work fast and it is generic so that it can generate hard

shadows in real- time for any type of objects independently of their complexity. Two

example screenshot that illustrates a 3D representation of a simple cube (Figure 7, a)

and a tree (Figure 7, b) is shown in Figure 7.



Figure 7: Hard shadows (a) Canonical shape (cube, left) (b)

Non-canonical shape (tree, right) The main disadvantage of this algorithm is that it

renders the virtual information twice for each frame: once for the virtual object and

another one for its shadow. Another obvious flaw is that it can cast shadows only into

planar surfaces but with some modifications, it can be extended to be applied to

specific cases such as curved surfaces.

4.4. Fake Shadows

Although hard shadows will increase the level of realism to the AR scene, there are

still a lot of issues for achieving realistic rendering. In theory, any projection matrix

which generates hard shadows can be used for the generation of soft shadows

[Mol99]. To generate the effect of soft shadows the same principle may be applied

with some modifications. The shadow matrix needs to be calculated only once, but

the augmentation of the matrix must be performed for some 3D points that much

have a small displacement from the origin and can cover the area near the hard

shadow as illustrated in Figure 8.



Figure 8: Approximation of soft shadows A

Although this technique is not very computationally expensive, it does not provide

very realistic results. However, if a large number of displacements are used, then it is

possible to improve the visualisation results. To achieve more realism other

techniques, such as a frustrum-based method, need to be employed [Mol99]. 5

Reflection Generation Reflections are one of the most important ingredients for

realistic computer graphics visualisation [Mol99]. The general lighting equation also

called the rendering equation accounts for reflections and shadows [Kaj86]. The light

reflection depends on four different factors as shown from the equation [Wat99]

below:

Where LI is the light incident at a surface, LR is the reflected light, LS is the light

scattered, LA is the absorbed light and LT is the transmitted light. Reflection is a

rendering technique that generates images that look similar to ray-traced images

without having to trace the reflected rays. This implies that an instance of the real

world is painted onto a surface as it is rendered [Ang03]. In this work, two different

types of reflections have been implemented including environmental reflections and

planar reflections.



5.1. Environmental and Spherical Mapping

Environmental mapping, also known as reflection mapping, is a simple and effective

method of generating approximations of reflections in curved surfaces [Mol99]. It is

usually classified as category of texturing technique and can be considered as a

simplification of ray tracing [Wat99].The difference with ray-tracing is that this

mapping makes use of the direction of the reflection vector as an index pointing to an

image that contains the environment [Mol99]. An illustration of how environmental

mapping works is illustrated in Figure 9.

Figure 9: Environmental mapping

In Figure 9, the graphics camera represents the user and is defined as a vector c, the

normal of the object is defined as N and the reflection vector as r. Using these

attributes, the reflection vector of the viewer can be computer using the following

equation [Ang03], [Mol99]:



r = 2(N * c)N - c

where c represents the normalised vector from the graphics camera to the location of

the surface, and N is the surface normal at that location. Although, the main

limitation of environmental mapping is that the artefacts near the reflector can not be

reflected accurately it can also be used to give limited recursive reflections [MB99].

Additionally, it is possible to achieve a variation of the above method, called spherical

mapping [Ang03]. The idea is to map the environment into a sphere using

orthographic projection and then generate a texture. In this work, the image is stored

in image memory and the texture coordinates are generated automatically. The main

advantage of this technique is that it is simple to implement and provides a rough

estimation of reality. Two example screenshots illustrate how spherical mapping can

be applied on a textured 3D virtual artefact. Figure 10, (a), shows a 3D artefact with

simple texturing applied, while Figure 10, (b) illustrated the same 3D artefact with

sphere mapping.

Figure 10: Environmental mapping (a) simple texture mapping (b) sphere mapping

Another way of accurately computing the environmental map is to use standard

projections [Ang03]. In the simplest case of an AR indoor environment at least six

cameras are required to estimate six projections [Vin95]. Each projection

corresponds to each surface of the indoor environment (i.e. a kiosk environment



inside a museum). Using all six projections a single environmental map can be

generated. This can be then easily applied to the model as a single texture.

5.2. Planar Reflections

To realistically model reflections in AR heritage environments, many issues must be

taken into account. For example, in reality the light is scattered uniformly in all

directions depending on the material.

Figure 11: Reflection in a plane



In this work, the effect of mirror reflections has been implemented. Based on the

capabilities of the stencil buffer, a reflection of the object is performed onto the

virtual ground which is user-defined. The stencil buffer is initially set sixteen bits in

the pixel format function. Then, the buffer is emptied and finally the stencil test is

enabled.

Figure 12: Transparency in a user-defined plane

In Figure 12, a 3D object is overlaid on a marker card and its planar reflection is

projected on a user defined plane. Transparency is used to the virtual plane in order

to emphasise the appearance of virtual artefact. To enhance the realism of the AR

reflections, hard shadows can be projected onto the same plane.

6. Conclusions and Future Work

Realism in AR exhibitions is one of the means that museums can use to so attract the

visitor’s attention. This paper has illustrated how realistic AR kiosk exhibitions of

museum collections, including galleries and artefacts, can be developed in real-time

performance. Advanced computer graphics rendering algorithms such as interactive

lighting and shading, fake, soft and hard shadows and reflections are standard



features that must be included in any augmented exhibition. In the future, shadows

and reflections will be extended to operate in curved surfaces. In addition, more

advanced rendering techniques will be implemented including level-of-detail,

collision detection and ray- tracing. Finally, a lite version of the AR interface will be

ported into a handheld device such as smartphones and personal digital assistants

(PDAs) allowing for mobile AR realistic rendering inside museums.

Acknowledgments

The author would like to thank the Department of Creative Computing at Coventry University

as well as the Centre for VLSI and Computer Graphics at the University of Sussex for their

support and inspiration.

References

[Ang03] Angel, E., Interactive Computer Graphics: A Top-Down Approach Using OpenGL, Addison-

Wesley, Third Edition, 17-18, 69, 107, 322-349, 472, (2003).

[Arn00] Arnold, D.B., Computer Graphics and Archaeology: Realism and Symbiosis, In Joint ACM

SIGGRAPH and EUROGRAPHICS Campfire on Interpreting the Past in Preconference Prroceedings,

10-21, (2000).

[AT*01] Andersen, D., Thomsen, C., et al., ARS- Generator - An augmented reality shadow generator,

Report, Aalborg University, Department of Computer Science, 4th Sep-19th Dec, (2001).

[BA*99] Brogni A., Avizzano C.A., et al., Technological Approach for Cultural Heritage: Augmented

Reality, Proc. of the 8th Int’l Workshop on Robot and Human Interaction, Pisa, Italy, (1999).

[BB*01] Baber, C., Bristow, H., et al., Augmenting Museums and Art Galleries, Human-Computer

Interaction INTERACT '01, 439-447, (2001).



[Bea04] Beaker, H., Computer Graphics with OpenGL, Pearson Prentice Hall, Third Edition, 644,

(2004).

[BF*01] Bimber, O., Frohlich, B., Schmalsteig, D., and Encarnacao, L.M., The Virtual Showcase,

Computer Graphics and Applications, IEEE Computer Society, 21(6): 48-55, Nov/Dec, (2001).

[BNB05] Buchmann, V., Nilsen, T., and Billinghurst, M., Interaction With Partially Transparent Hands

And Objects, Proc. of the Sixth Australasian conference on User interface, ACM Press, Volume 40,

Newcastle, Australia, 17-20, (2005).

[BS95] Boisvert, D.L., and Slez, B.J., The relationship between exhibit characteristics and learning-

associated behaviours in a science museum discovery space, Science Education, 79(5), 503-518,

(1995).

[DRB97] Drettakis, G., Robert, L and Bougnoux, S., Interactive Common Illumination for Computer

Augmented Reality, Proceedings of Rendering Techniques '98 (Eighth EG Workshop Rendering), J.

Dorsey and P. Slusallek, eds., 45-56, June, (1997).

[Gat00] Gatermann, H., “From VRML to Augmented Reality Via Panorama- Integration and EAI-

Java, in Constructing the Digital Space”, Proceedings of the SiGraDi, 254-256, September (2000).

[HC*01] Hall, T., Ciolfi, L., et al., The Visitor as Virtual Archaeologist: Using Mixed Reality Technology

to Enhance Education and Social Interaction in the Museum, Proc. of Virtual Reality, Archaeology, and

Cultural Heritage, ACM Press, Glyfada, Nr Athens, November, 91-96, (2001).

[HCC05] Huang, C.R, Chen, C.S, Chung, P.C., Tangible Photorealistic Virtual Museum, Computer

Graphics and Applications, IEEE Computer Society, January/February, 25(1): 15-17, (2005).

[Kaj86] Kajiya, J.T., The rendering equation, Computer Graphics (SIGGRAPH), 20(4): 143-150,

August, (1986).

[LDR00] Loscos, C., Drettakis, G., and Robert, L., Interactive Virtual Relighting of Real Scenes,

Transactions on Visualisation and Computer Graphics, IEEE Computer Society, 6(4): 289-305,

(2000).



[Lia07] Liarokapis, F., An Augmented Reality Interface for Visualising and Interacting with Virtual

Content, Virtual Reality, Springer, 11(1): 23-43, (2007).

[LS*04] Liarokapis, F., Sylaiou, S., et al., An Interactive Visualisation Interface for Virtual Museums,

5th International Symposium on Virtual Reality, Archaeology and Cultural Heritage, Eurographics

Association, Brussels, Belgium, 6-10 Dec, 47-56, (2004)

[MB99] McReynolds, T., and Blythe, D., Advanced Graphics Programming Techniques Using OpenGL,

SIGGRAPH `99 Course, (1999).

[MK*97] Mase, K., Kadobayashi, R., et al., Meta-Museum: A Supportive Augmented-Reality

Environment for Knowledge Sharing, ATR Workshop on Social Agents: Humans and Machines, Kyoto,

Japan, April 21-22, (1997).

[Mol99] Moller, T., Real-Time Rendering, A K Peters Ltd, 23-38, 171, (1999).

[SL*05] Sylaiou, S., Liarokapis, F., et al., Virtual Museums: First Results of a Survey on Methods and

Tools, CIPA XX Symposium, Torino, Italy, Sept 26-1 Oct, 1138-1143, (2005).

[SW*99] Shreiner, D., Woo, M., et al., OpenGL Programming Guide: The Official Guide to Learning

OpenGL, Version 2 (5th Edition), Addison Wesley, August, (2005).

[Vin95] Vince, J., Virtual Reality Systems, Addison-Wesley Publishing Company, 180-182, 288-292,

(1995).

[Wat99] Watt, A., 3D Computer Graphics, Addision-Wesley, Third Edition, December 6, (1999).

[WM*04] White, M., Mourkoussis, N., et al., ARCO-An Architecture for Digitization, Management and

Presentation of Virtual Exhibitions, Proc. of the 22nd Int’l Conference on Computer Graphics

(CGI'2004), IEEE Computer Society, Hersonissos, Crete, June 16-19, 622-625, (2004).



FOTIS LIAROKAPIS

Fotis is the director of Interactive Worlds Applied Research Group (iWARG), Faculty of Engineering

and Computing at Coventry University and a research fellow at the Serious Games Institute. He has

contributed to more than 75 refereed publications with more than 600 citations and has been invited

60 times to become member of international conference committees and has chaired 13 sessions in 8

international conferences.Fotis is the editor in chief of the International Journal of Interactive Worlds

(IJIW) and he is on the editorial advisory board of The Open Virtual Reality Journal. He has organised

VS-Games 2009 (publications chair), the STARS session of VAST 2009 (chair of state-of-the-art

reports), VS-Games 2010 (steering committee) and VS-Games 2011 (general chair). Finally, he is a

member of IEEE, IET, ACM, BCS and Eurographics.

MORE: fotisliarokapis.blogspot.com/

http://www.fotisliarokapis.blogspot.com/

Documents

Realistic Rendering of Augmented Reality Heritage Exhibitions CyberEmathy8/2014