Using 3D digital models for the virtual restoration of polychrome in interesting cultural sites

This is a previous version of the paper Using of 3D Digital Models for Polychromies Virtual Restoration on Interesting Cultural Sites, appeared in the Journal of Cultural Heritage, vol. 15 (2014), pp. 196-198. The final publication is available at Springuer via http://doi:10.1016/j.culher.2013.03.009

Using of 3D Digital Models for Polychromies Virtual Restoration on

Interesting Cultural Sites

Pedro Martín Lerones*, José Llamas Fernández

Fundación CARTIF

Parque Tecnológico de Boecillo, P. 205

47151-Boecillo, Valladolid (Spain)

Phone: +34.983.54.89.20; FAX: +34.983.54.65.21

[email protected], [email protected]

Jaime Gómez-García-Bermejo, Eduardo Zalama Casanova

ETSII - Universidad de Valladolid

Paseo del Cauce, s/n

47011- Valladolid (Spain)

Phone: +34.983.42.35.45; FAX: +34.983.42.33.58

[email protected], [email protected]

Jesús Castillo Oli

Fundación Sta. Mª. La Real

Avda. Ronda, 1 y 3

34800 - Aguilar de Campoo (Palencia) - Spain

Phone: +34.979.12.50.00; FAX: +34.979.12.56.80

[email protected]

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mailto:[email protected]






Abstract

The use of ICT in the research, protection, conservation, restoration and diffusion

of cultural heritage is giving rise to experiences that enable to put in value and

offer new ways of use and exploitation of cultural interesting immovable assets.

The paintings (polychromies) that decorated them in the majority of cases do not

actually exist or are reduced to mere remnants. These facts decontextualize the

sites in its historical and artistic evolution, distort them of the intention under

which they were conceived, and hamper his performance. Current recovery

methods are restricted to the stabilization of the remains in the status in which

they are, requiring a completely manual work that is expensive and almost

unrelated to the use of new technologies.

On the other hand, three-dimensional digitalization and modelling is proved to be

the basis for the virtual recovery of polychromies in a significant place. To do so,

an innovative methodology is presented, which involves the development of a

computer tool that allows to combine the 3D geometric information of a site

(captured using a laser scanner), with 2D specially designed artificial images. The

resulting 3D digital models are ready both to be directly thrown with high

luminous efficiency projectors on the original site, and also used as raw material

to compose a video-projection without perspective effects to emulate their

primitive appearance, its evolution along time (in accordance to historical or

artistic stages), the effects of the deterioration, or to show other alternative aspects

with due rigour.

To illustrate the methodology to be described, the results obtained at St. Mary of

Mave (Palencia, Spain) are presented.

Keywords: digital modelling / texture mapping / digital projection / video

mapping / 3D virtual recovery / 3D virtual reconstruction.

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1. Research aims

The objective of the present work is to define a novel methodology for obtaining

3D digital models texturized with specifically designed images to be used as a

basis for animation and projection techniques aimed at virtual recovering of the

indoor paintings of a historic place over time.

With this purpose, an applied research work has been performed, that consists of a

quick and effective 3D/2D combination by means of well-known calibration

algorithms never used in heritage context, leading to a state-of-the-art computer

tool.

Therefore, hyper-realistic digital models of morphologically very complex objects

will be built. Their usefulness not only in the creation and editing of the projection

contents, but also in the determination of the optical parameters and positioning of

the projectors to become them visible, will be studied. Problems that may arise

due to the influence of the ambient lighting and the colour of the surface focused

will also be described. All this will make possible to achieve not discordant

mountings regarding the aesthetics and functionality of the site.

2. Introduction

Laser scanners are already known for accurate three-dimensional measurement in

architecture and heritage, but they have had to wait for significant progress in the

electronics and in the calculation ability of computers to be actually really used.

The recently successful processing capacity to 64-bit of PCs to transcribe the data

obtained, has been a mainstay in this sense.

Thus, nowadays the medium-long range laser scanners are both an alternative and

a complement to classical measuring methods such as Topography and

Photogrammetry [1, 2, 3]. The two technologies they are based on are "phase

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shift" and "time of flight" [4, 5]. With either of them, by placing the scanner in

different positions, a laser beam is running over the surface to be automatically

digitized (indoor and/or outdoor) according to a pre-set geometric resolution1. The

geometric coordinates (X, Y, Z) of the required registered points are obtained

regarding the position of the scanner. All of these points make a "cloud" that

perfectly describes the measured geometry. The colour coordinates (R, G, B) of

these points are optionally acquired by means of digital cameras, internally or

externally coupled to the scanner. However, the computed colour varies

throughout the process depending on the ambient lighting, being also limited by

the geometrical resolution.

The partial clouds from each position are aligned to give rise to the global point

cloud that describes the original site. Since it is necessary that the digitized

surfaces appear clearly defined, the global cloud becomes a polygonal model,

which, for simplicity reasons, is a triangle mesh2 [6, 7].

Hence, a digital model that turns out to be a virtual replica of the scanned location

or area is created. Not only pictures of the original place could be overlapped on

that model to give a more realistic appearance, but images of all kinds (in size and

content). In both cases the 3D geometry (mesh) has to be related to each image

(2D). Commercial tools available for this operation are very limiting, so a specific

technique has been developed along with an associated computer program that

solves the three problems intrinsic to these tools. Thus, the new technique:

Allows the superposition of images without limiting the perspective.

Operates at any resolution.

Do not require a calibrated camera when working with photographs.

1 Distance between consecutive registered points. The medium resolution used at St. Mary of Mave was: 3 cm @ 7 m. 2 The reasons to use triangles are plenty: the recorded information is kept; they are the simplest mathematical figure to connect neighbouring points; and, at the same time, they offer the lower computer processing cost.

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The versatility and strong innovative character that constitute these three features

represent a breakthrough against recent works such as Kersten, Lindstaedt and

Vogt [8] or Yuksel, Keyser and House [9].

This new technique can be used to overlay specifically designed images, allowing

to obtain 3D digital models that could be focused on specific areas of an

interesting cultural asset by means of data projectors to supplement or emulate

polychromies (indoors or night-time outdoors3). This projection facilitates both

virtual restorations (showing it would be like originally, emulating the result of an

expected intervention, or even guiding it), as simulations of successive pictorial

stages and their damage. No physical intervention on the surface will be required

in any case, offering substantial additional information not only for specialists but

also for general public. Light intensity does not harm the material support on

which is projected (by temperature, exposure time nor discoloration).

The obtained 3D model is first used to calculate the positioning and optics of the

projectors required, thereby saving travels and difficult measurements on site.

Secondly this digital model is ready to be used to create a video projection.

Overlapping one by one the images specifically built for the planned recreation,

different screenshots are captured to make up a single scene from each projector.

It is important to stress that each screenshot is an optical distortion-free frame, and

sequencing all of them in a professional video editing program makes the 3D

video projection to show desired effects.

In Europe there are results of interest, but limited to small objects. A referrer is

the projection of a 3D model that emulates the appearance of the head and chest

of the “White Virgin” in the 19th century at the Vitoria’s Cathedral (Spain) [10].

However, the projection in large areas is restricted to spectacular sound and light

shows that are solved in 2½D with the data projectors by their own. Multiple

examples mainly on facades are easily found on the Internet, but a very few are

3 The lighting is controllable indoors, fact not feasible outdoors.

5

https://www.researchgate.net/publication/240954566_Virtual_Restoration_of_Cultural_Heritage_Through_Real-Time_3D_Models_Projection?el=1_x_8&enrichId=rgreq-9c38d669-8361-48de-8a73-d25946140b8d&enrichSource=Y292ZXJQYWdlOzI1ODEyMTA4NjtBUzoyMjgyNzY2NjQ3OTUxMzdAMTQzMTQzNjgwNjU5MA==


interesting for cultural heritage, as is the case of the “Portico de la Luz4” in the

Chapel of Paternina, also in the Vitoria’s Cathedral.

This article details the methodology to generate the 3D models used as the basis

of the experimental video projection on the central apse and two significant

capitals of the Romanesque church of St. Mary of Mave (Palencia, Spain) and the

setting-up required. In this singular building, spectacular effects has been avoided

to recreate the four pictorial stages that currently could be visited individually in

some of the 54 temples that constitute the "Romanesque North5" area (the largest

concentration of Romanesque monuments all over the world), keeping the utmost

historical rigour. Finally, conclusions and foreseeable advances will be addressed.

Those are intended to carry out developments that expand and satisfy the

professional and social demand for these jobs, which have been slowed down by

the current economic situation.

3. Methodology

After chemical or mechanical removal of mortar or dirt under which polychromies

usually appear, its recovery is a work of highly qualified staff, economic and

temporarily expensive, with an absolute degree of manual intervention. This

recovery is never complete, and is restricted to the stabilization of the findings in

the state they actually are (Fig1).

Using data projectors, both artificially texturized 3D digital models and video

shows based on them could be focused on specific areas of the selected site to

supplement or emulate polychromies. In both cases the core is the superimposition

of images to the mesh resulting of the triangulation of the point cloud given by the

scanner [11].

4 http://www.youtube.com/watch?v=K7YB6KMm6yU 5 www.romaniconorte.org

6

https://www.researchgate.net/publication/227903777_High-precision_texture_mapping_on_3D_free-form_objects?el=1_x_8&enrichId=rgreq-9c38d669-8361-48de-8a73-d25946140b8d&enrichSource=Y292ZXJQYWdlOzI1ODEyMTA4NjtBUzoyMjgyNzY2NjQ3OTUxMzdAMTQzMTQzNjgwNjU5MA==


3.1. 2D to 3D superimposing

Such overlapping leads the development of special software tool, starting-up with

a correspondence between each image (2D) and the mesh (3D) according to

Zalama et al. [12]. This involves calculating the necessary matrices using the Tsai

[13] or the Zhang [14] equivalent method, what means employing at least 11

control points obtained by selecting common ones between the image and the

mesh in a specially developed computer tool with a friendly user interface (Fig.2).

The process is repeated using all the required images regardless of their format,

size, and absolute or relative resolution. This produces a digital model that turns

out to be an optimized meshing with the images overlapped as "skin". The

resulting VRML6 file can be viewed in any standard browser, or used for

multimedia or virtual and augmented reality applications [15, 16].

Now, the resulting 3D model can be handled (basically rotation, pan-tilt, and

zoom) in standard software for 3D data processing and editing7 to previously

calculate the placement of the projectors (distances and angles), in accordance

with the view that will be taken from each one (Fig. 3). It must be taken into

account that the calculated disposition needs consensus to avoid montages that are

not consistent with the aesthetics or functionality of the site.

Once the projection perspective is achieved, the width really covered by each

view and the distance from the furthest point on it to each projector are calculated

(metrics provided by the 3D model). Both parameters are used to determine the

focal length of the lens required by each projector, being characterized the optics

that will be necessary to acquire.

6 Virtual Reality Modelling Language: standard file format devoted to the representation of three-dimensional interactive graphics. 7 PolyWorks in our case.

7

https://www.researchgate.net/publication/220373560_An_Effective_Texture_Mapping_Approach_for_3D_Models_Obtained_from_Laser_Scanner_Data_to_Building_Documentation?el=1_x_8&enrichId=rgreq-9c38d669-8361-48de-8a73-d25946140b8d&enrichSource=Y292ZXJQYWdlOzI1ODEyMTA4NjtBUzoyMjgyNzY2NjQ3OTUxMzdAMTQzMTQzNjgwNjU5MA==

https://www.researchgate.net/publication/224729857_Tsai_RY_A_Versatile_Camera_Calibration_Technique_for_High-Accuracy_3D_Machine_Vision_Metrology_Using_Off-the-Shelf_TV_Cameras_and_Lenses_IEEE_Journal_of_Robotics_and_Automation_3_323-344?el=1_x_8&enrichId=rgreq-9c38d669-8361-48de-8a73-d25946140b8d&enrichSource=Y292ZXJQYWdlOzI1ODEyMTA4NjtBUzoyMjgyNzY2NjQ3OTUxMzdAMTQzMTQzNjgwNjU5MA==

https://www.researchgate.net/publication/3193178_A_Flexible_New_Technique_for_Camera_Calibration?el=1_x_8&enrichId=rgreq-9c38d669-8361-48de-8a73-d25946140b8d&enrichSource=Y292ZXJQYWdlOzI1ODEyMTA4NjtBUzoyMjgyNzY2NjQ3OTUxMzdAMTQzMTQzNjgwNjU5MA==

https://www.researchgate.net/publication/248546261_From_3D_reconstruction_to_virtual_reality_A_complete_methodology_for_digital_archaeological_exhibition?el=1_x_8&enrichId=rgreq-9c38d669-8361-48de-8a73-d25946140b8d&enrichSource=Y292ZXJQYWdlOzI1ODEyMTA4NjtBUzoyMjgyNzY2NjQ3OTUxMzdAMTQzMTQzNjgwNjU5MA==


Then again a screenshot of the perspective projection in the 3D model is made,

giving rise to an image that fits without any deformation to the corresponding

original area when it is projected, since it sums up the third dimension (depth). In

this way distortion errors inherent to direct equivalent use of the images utilized in

the overlapping (previously corrected in perspective) are minimized. Finally, the

captured images will serve as base frames to be edited in video software to create

effects for virtual recreations.

3.2. Equipment and installation

The Church of St. Mary of Mave, due to its constructive purity is one of the

landmarks of the “Románico Norte”. It was restored in 2008, bringing back the

existing paintings located on the inner side of the two lateral apses. In the central

apse, which is the largest and also the main focus of attention in the interior of the

temple, there is no rest of any paint, so is the appropriate part for the 3D video

projection. Since polychromies on the capitals are very important, and none are

currently decorated in Mave, the two capitals that precede the apse (facing the

altar) are considered for the projection as well.

The restoration has been scrupulously faithful in its historical and artistic facets so

all technology added to the Church should go unnoticed. This leaded to take the

decision of using a single data projector placed on the lintel of the temple’s

entrance door. The distance between the projector and the dome of the central

apse is maximized in this case, which meant a significant technological challenge

not only to define the necessary equipment for the video projection, but for the

quality of this by itself.

Thus, the installation consists of a conventional computer (whose graphics board

is used to control the video effects), just next and connected to the projector (Fig.

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4). Both are electrically powered from a same 220V socket provided with UPS8.

The computer is isolated from the static current running on the door (made on

metal) by shimming it on a plate of wood as an insulator. Otherwise, the projector

is placed on a pre-existing joist, useful to isolate it from vibrations and subsequent

displacement that might incur by opening and closing the entrance door. Keeping

the position of the canon fixed is critical to procure the 3D video projection be

properly framed.

Combining technical needs with economic possibilities, the chosen projector was

a Christie 6000 lm light output, contrast 1: 1000, XGA (1024 x 768) resolution,

and 4:3 scene aspect ratio. This canon attaches a 26 mm focal lens, calculated

according to two parameters deducted from the 3D model of the church and based

on the items to be covered with the video projection: throw distance (26 m); field

of view of 10 m (wide) x 7.5 m (high).

The projector turns on and off via an infrared remote control unit. At the same

time, the PC starts and stops by radio frequency with a second remote control. A

small wireless keyboard allows accessing, stopping and resuming the video

projection.

3.3. Arising problems

To ensure the projections are neatly (even indoors), the influence of the Sun and

other possible sources of illumination which impact on the place where those are

focused, must be studied in detail. Artificial lightning could always become

extinct or accommodated to the video projection, but natural lightning in

Romanesque temples, generally dark9, may present pathological areas according

to time of day and season of the year. It is the case of the windows of the apse,

8 Uninterruptible Power Supply: It is a device ready to supply electrical power to all devices connected after a power failure. Also filters increases and decreases in electrical power, and eliminates harmonics (distortions) from the mains. 9 According to measurements in situ, the average light intensity does not exceed 400 lx indoors.

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oriented to the East, so, seeking for the best results, it is recommended do not run

the projection from the Sun rising until it reaches the zenith on sunny days.

Another important aspect to consider is the colour of the surface on which the

projection is focused, that could significantly modify the colour of the thrown 3D

model. It is possible to properly modify the colour of the 3D model in such a way

that when being projected onto the surface, both colorations are compensated,

reaching a more faithful and realistic viewing.

If they were used several data projectors whose projections overlap each other, the

partial projections arising from each one should be controlled, corrected and

homogenised. However multiple projections is currently a technical challenge that

must be solved taking into account all the aspects that would be involved, which

have been formally put forward in the work of Damera-Venkata, Chang y Di

Carlo [17].

4. Results

The conventual church of St. Mary of Mave was fully digitized in 2010 for

documentation purposes. Taken as 3D model the cut corresponding to the area

where the video projection should be made, it is applied the methodology

described, being superimposed the images onto these defined elements: two

capitals prior to the apse; and on the apse itself: the upper and lower lancet arches,

the interior of the semi-circular arch, the vault, the cornice under the vault, and the

jambs (continuation of the lower arch).

Every single image superimposed on each of these elements corresponds to a

specific historical period, and within it, to a phase of its life (from the lines

drafting, passing through the painting, until later deterioration). The capture of the

screen with every required set of images according to the perspective of the

projector gives rise to a video frame. Sequencing of all them an editable video

devoid of perspective effects is performed.

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The 3D video projection of Mave is also different because it has fled of effects

and spectacular transitions, making soft joining between stages without sound

accompaniment. It summarizes the four historical phases of interest in the

“Románico Norte”:

1. Romanesque (pantocrator of the Hermitage of St. Eulalia, in Barrio de Santa

María, Palencia).

2. Gothic (maiestas of the Church of the Assumption, in Barrio de Santa María,

Palencia).

3. Renaissance (existing paintings in the Church of Mave).

4. Baroque (paintings of the Church of St. Christopher the Martyr, in Ailanes -

Burgos-).

Delineation strokes are fine and colours not stand out over the rest of the paintings

in the Church to make the effects more realistic. Once completed the appearance

of each stage, it will be displayed a reasonable time so that the visitor can

appreciate it better, being also surprised by the mutation of the contents, but

keeping a natural continuation of the architectural and artistic context existing in

the temple at the same time.

4.1. Romanesque stage

[Pending]: De arriba a abajo, y de izquierda a derecha, la Fig. 5 muestra la

situación de partida, la delineación y el pintado de la etapa románica.

4.2. Gothic stage

Starting up with a plastering, it continues with the delineation and painting (richer

in strokes and shades of colour than the Romanesque, as can be seen in this

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period’s maiestas), to end with a deterioration by blurring. Fig. 6 shows the

pictorial culmination of the Gothic stage.

4.3. Renaissance stage

In this phase it is faced the recreation of the paintings that are equivalent to those

actually existing in the apses of the gospel and epistle naves, giving them

continuity.

For this reason, this is the most important step to verify if the 3D video projection

truly emulates the reality, being necessary to regulate the colour intensity by using

the canon through the PC’s graphic card to which is connected.

However, the definition of the drawings of the upper and lower arches is not clear

due to the decorative profusion and coloration of the images superimposed on the

mesh for this stage. Since the projection is made more than 25 m distance away,

the size of the pixel defining the strokes does not allow a correct visualization.

This shows the importance of the design of the images to overlap (Fig. 7).

4.4. Baroque stage

It is the case of greatest artistic profusion (strokes and coloration), appearing even

an additional element (curtains around the central window) that extends the

existing Christ behind the altar. As this cannot be removed, it is isolated in the

projection.

This stage is useful to show the degradation by peeling and progressive blurring

(Fig. 8), that are the main aspects of the deterioration of the paintings in the

churches of the area by the severe climatic conditions.

5. Conclusions

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The use of medium-long range laser scanners allows obtaining meshes ready to be

texturized with particularly designed images to virtually simulate and recover the

missed or incomplete polychromies in immovable cultural assets. It thus gives rise

to a methodology whose technical and economic viability has been revealed with

the simplest installation possible in an emblematic site such as St. Mary of Mave

(Palencia, Spain), making compatible their aesthetics with the historical and

artistic rigor of the contents.

The objective is eminently educational and oriented to diffusion. Setting up the

system, visitors can better understand how the Romanesque churches were

decorated and how have evolved the paintings along time. All this has been made

without altering the building, being focused the projections on a currently empty

surface, on which no longer exist traces of paint.

More complex and not discordant mountings on the chosen site (or other

interesting one) are expected to be possible, taking into account the problems

associated with multiple projections, which are set by the optical parameters of

each projector employed, the overlap between projections, the colour of the

surface, and the ambient lighting. Surely this is going to lead to future R&D

projects that entail a clear differentiation and added value to significant heritage

sites.

Acknowledgements

The described methodology has been developed under a project funded by the

Economic Development Agency (ADE) of the Spanish Regional Government of

‘Castilla y León’, through the program "Innoempresa", co-financed by FEDER

(Project No. 2110/PA/0014). The new application is in accordance with the works

developed in the temple by the staff of the “Románico Norte intervention Plan”,

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promoted by the Regional Ministry of Culture and Tourism in collaboration with

the Bishops of Palencia and Burgos.

References

[01] S. Linsinger, 3D Laser versus stereo photogrammetry for documentation and

diagnosis of buildings and monuments (pro and contra), Proceedings of the CIPA

XX International Symposium, Torino (Italy), September 26 - October 1, 2005.

[02] K. Lambers, H. Eisenbeiss, M. Sauerbier, et al., Combining photogrammetry

and laser scanning for the recording and modelling of the late intermediate period

site of Pinchango Alto, Palpa, Peru, Journal of Archaelogical Science 34(10)

(2007) 1702-1712.

[03] S. Al-Khedera, Y. Al-Shawabkeh, N. Haala, Developing a documentation

system for desert palaces in Jordan using 3D laser scanning and digital

photogrammetry. Journal of Archaeological Science, 36(2) (2009) 537-546.

[04] G. Bradshaw, Non-contact surface geometry measurement techniques, Image

Synthesis Group, Trinity College, Dublin, 1999.

[05] G. Sansoni, M. Trebeschi, F. Docchio, State-of-The-Art and Applications of

3D Imaging Sensors in Industry, Cultural Heritage, Medicine, and Criminal

Investigation. Sensors, 9 (2009) 568-601.

[06] F. Remondino, S.F. El-Hakim, Image-based 3D modeling: a review, The

Photogrammetric Record Journal 21(115) (2006) 269-291.

[07] Y. Arayici, An approach for real world data modelling with the 3D terrestrial

laser scanner for built environment, Automation in Construction 16(6) (2007)

816-829.

[08] T.P. Kersten, M. Lindstaedt, B. Vogt, Preserve the Past for the Future -

Terrestrial Laser Scanning for the Documentation and Deformation Analysis of

Easter Island's Moai. Photogrammetrie Fernerkundung Geoinformation, 1 (2009)

79-90.

[09] C. Yuksel, J. Keyser, D.H. House, Mesh Colors. ACM Transactions on

Graphics, 29 (2) (2010) Article 15.

14


[10] R. Peral, D. Sagasti, R. Sillaurren, Virtual Restoration of Cultural Heritage

Through Real-Time 3D Models Projection, Proceedings of the 6th International

Symposium on Virtual Reality, Archaeology and Cultural Heritage, Pisa (Italy),

October 30-November 4, 2005.

[11] Y. Iwakiri, T. Kaneko, High-precision texture mapping on 3D free-form

objects. Electronics and Communications in Japan Part II – Electronics, 89(9)

(2006) 24-32.

[12] E. Zalama, J. Gómez-García-Bermejo, J. Llamas, R. Medina, An Effective

Texture Mapping Approach for 3D Models Obtained from Laser Scanner Data to

Building Documentation. Computer-Aided Civil and Infrastructure Engineering,

26(5) (2011) 381-392.

[13] R.Y. Tsai, A Versatile Camera Calibration Technique for High-Accuracy 3D

Machine Vision Metrology using Off-the-self TV Cameras and Lenses, IEEE

Journal of Robotics and Automation 3(4) (1987) 323-344.

[14] Z. Zhang, A flexible new technique for camera calibration. IEEE

Transactions on Pattern Analysis and Machine Intelligence 22(11) (2000) 1330-

1334.

[15] F. Bruno, S. Bruno, G. De Sensi, M-L. Luchi, S. Mancuso, M. Muzzupappa,

From 3D reconstruction to virtual reality: A complete methodology for digital

archaeological exhibition. Journal of Cultural Heritage, 11(1) (2009) 42-49.

[16] Z. Noh, A.W. Ismail, M.S. Sunar, Exploring the Potential of Using

Augmented Reality Approach in Cultural Heritage System, Proceedings of the

2nd International Conference on Advanced Computer Theory and Engineering,

Cairo (Egypt), 25-27 September.

[17] N. Damera-Venkata, N. Chang, J. Di Carlo, A unified paradigm for scalable

multi-projector displays. IEEE Transactions on Visualization and Computer

Graphics, 13(6) (2007) 1360-1367.

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Fig. 1: Restoration of the polychromies of the apse in the church of St. Mary of

Mave.

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Fig. 2: 2D/3D correspondence by manually marking of respective control points.

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Fig. 3: 3D model showing the superposition of images on important elements of

St. Mary of Mave. The screenshot corresponds to the perspective from the

entrance door.

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Fig. 4: Location of the projector and the computer for the 3D video projection at

St. Mary of Mave.

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Fig. 5: Situación de partida y ejemplos de secuencia de la etapa Románica.

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Fig. 6: Vista de la etapa Gótica de la videoproyección 3D.

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Fig. 7: Evolución de la policromía de la etapa Renacentista.

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Fig. 8: Secuencia de imágenes de la etapa Barroca de la videoproyección 3D.

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Documents

Using 3D digital models for the virtual restoration of polychrome in interesting cultural sites