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Perceptually Valid Images of Conimbriga Using High Dynamic Range

Alexandrino José Marques Gonçalvesalex@ipleiria.pt

November 4th, 2010

Supervisors:João Paulo Moura (University of Trás-os-Montes and Alto

Douro)Alan Chalmers (University of Warwick, UK)

A thesis submitted to the University of Trás-os-Montes and Alto Douro in accordance with the requirements for the degree of Doctor of Philosophy

Motivation

Purpose

Results

Contributions

Conclusions

“The (Roman light) image makes me feel so warm… it makes me comfortable.”Sicheng Zhang _

Outline02

Do Cultural Heritage environments be

presented like their period in time? Do we perceive them equally?

Do we ‘look’ at them the same way?

Do we have the equivalent archaeological,

religious or architectural interpretation?

Are there clear benefits of using high fidelity

visualization in a cultural heritage context?

“The (Roman light) image... changes the colours of the frescoes and mosaic.”Nick Papanikolaou _

Motivation03

Civilization Roman;

Locale Conimbriga, Portugal.

Specificities Roman illumination;

Roman artefacts (frescoes and mosaics);

Dim conditions (no windows).“Oil lamps in a roman villa…”

Simon Scarle_

Motivation / Case Study04

Produce accurate and perceptually valid

high fidelity images of Conimbriga’s Roman

frescoes and mosaics.

Conduct a perceptual visual user study with

those high fidelity images.

“...making the room more attractive, the environment more soothing and relaxing...”Muhammad Latif_

Purpose05

High fidelity 3D model

High fidelity visualization

“The (electric light) image looked dull.”Sharon Edgar_

How to…06

Geometry;

Materials;

Ancient flame light simulation.

High Dynamic Range.

“...the low colour-temperature illumination is more in keeping with the original scenario.”Michael Goldsmith_

HDR… why?07

CIE Chromaticity Diagram

“The room looked to be old, therefore candlelight appeared to give the room a warm glow…”Gavin Edwards_

Results / Illumination experiments 0

8

Oil samples:

“...gave me an impression of warmth and softness.”Zaboronski Oleg_

09

Results / Illumination experiments

A special attention must be given to the origin and manufacture procedure of the fuel.

Additives:

“… (the electric light image) showing little shading effects and not highlighting colours and shapes.”

Thomas Rogers_

Results / Illumination experiments 1

0

We should also consider possible additives in ancient fuels as well.

“Looks warmer.”Arno Sawyer_

11

Results / Renderings

Real vs Virtual:

“More relaxing.”Margaret Arms_

12

Results / Renderings

Real vs Virtual:

“Warm. Comforting.”Weryaun(?) Zhuo_

13

Results / Renderings

“The (electric light) image… introduced more of a cold environment.”Carlo Harvey_

14

Results / Renderings

“The lighting in the image provides a more exciting/intriguing/mysterious ambience.”Hilmi Jaidin_

15

Results / Perceptual experiments

“… yellow light produces more vivid colours.”Matt Wakelin _

16

Results / Perceptual experiments

“The candle light is well captured…”Ioannis Agrafiotis _

17

Results / Perceptual experimentsEye tracking results: HDR images

“The light accentuates the colours and seems to change them.”Leigh Blount _

18

Results / Perceptual experimentsWhat is the colour of the circumferences viewed in the mosaic floor?

“... I liked it more because of the warm colours.”Elmedin Selmanovic _

19

Results / Perceptual experimentsWhich image did you like most?

“… (the electric light image) seems pale.”Himanshu Patel_

20

Results / Perceptual experimentsEye tracking results: HDR vs LDR (tone mapped image)

HDR LDR

The authentic Roman flame light simulation Awareness of the origin and manufacture procedure of the

fuel;

Consider possible additives to the fuel.

The cultural heritage high fidelity images

The perceptual visual user study using HDR Perceptual differences;

Viewing pattern altered;

Ancient light led to richer chromatic impression of the scene;

Visual acuity of HDR stand out in extreme lighting conditions.

“… is more natural in terms of lighting in olden days from which the frescoes appears to be.”Vibhor Aggarwal _

Contributions21

Publications

Gonçalves A., Magalhães L., Moura J., Chalmers A.

“Visualização de Espaços Arqueológicos usando High

Dynamic Range”. In Proceedings of V Congresso

CAAPortugal de Aplicações Informáticas à Arqueologia,

Leiria. 2007.

Gonçalves A., Magalhães L., Moura J., Chalmers A.

“Metodologia para Geração de Imagens High Dynamic

Range em Iluminação Romana”. In Proceedings of

International Association for the Scientific Knowledge -

InterTIC’07, Porto. 2007.

22

“... creates better contrast and highlights important areas of the scene.”Francesco Banterle_

PublicationsGonçalves A., Magalhães L., Moura J., Chalmers A. “High Fidelity

Illumination in Archaeology - A Roman Legacy in Portugal”. In 6th

World Archaeological Congress, WAC, Dublin. 2008.

23

Gonçalves A., Magalhães L., Moura J., Chalmers

A. “Accurate Modelling of Roman Lamps in

Conimbriga Using High Dynamic Range”. In

Proceedings of VAST 2008: International

Symposium on Virtual Reality, Archaeology

and Cultural Heritage, Braga. Eurographics.

2008.

Award: Best Paper Award“(The electric light image) was less pleasing and colourful…”Carlo Harvey_

Publications

Gonçalves A., Magalhães L., Moura J., Chalmers A.“Perceptual

Images of Conimbriga Using High Dynamic Range”. Journal

of Archaeological Science. Elsevier . 2011 (?).

24

Gonçalves A., Magalhães L., Moura J.,

Chalmers A. “High Dynamic Range - A

Gateway for Predictive Ancient Lighting”.

ACM Journal on Computing and Cultural

Heritage (JOCCH) 2(1): 1-20. ACM. 2009.

“... highlighting the colours and designs.”Gareth Edwards _

State of the Art Reports

Happa J., Mudge M., Debattista K., Artusi A., Gonçalves A.,

Chalmers A. “STAR Report on Illuminating the Past”. In

Proceedings of VAST 2009: International Symposium on

Virtual Reality, Archaeology and Cultural Heritage, Malta.

Eurographics. 2009.

Happa J., Mudge M., Debattista K., Artusi A., Gonçalves A.,

Chalmers A. “Illuminating the past: state of the art”. Virtual

Reality Journal, 14(3): 155-182. Springer. 2010.

25

“The (electric light) image looked very hash...which did not bring out the details in the mosaics...”

Gavin Edwards_

Article in Scientific Magazine26

NewScientist. “Ancient artefacts show up in a more flattering

light”. New Scientist Magazine (August 2009). 2720: 20.

2009.

“The (Roman light) image... was quite pleasing to the eyes.”Hardik Raja_

“… it is more clear that the room is Roman…”Isaac Lewis_

Conclusions27

Do Cultural Heritage environments be

presented like their period in time? Do we perceive them equally?

Do we ‘look’ at them the same way?

Do we have the equivalent archaeological,

religious or architectural interpretation?

Are there clear benefits of using high fidelity

visualization in a cultural heritage context?

No

No

Surely not

Yes

Absolutely

Alexandrino José Marques Gonçalvesalex@ipleiria.pt

“The (Roman) light seemed to give it a whole new atmosphere.”

Leonhard Widrich

Perceptually Valid Images of Conimbriga Using High Dynamic Range