ENHANCED OPTICAL METHODS FOR ANALYSIS OF HISTORICAL OBJECTS

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ENHANCED OPTICAL METHODS FOR ANALYSISOF
HISTORICAL OBJECTS

• Jan Bryscejn, Milo Drdácký, Jan Jakubek,
  Jaroslav Valach, Daniel Vavrík
• Peter Weiss
• Institute of Theoretical and Applied Mechanics of
  the Czech Academy of Science,ARCCHIP Centre of
  Excellence
• Institute of Experimental and Applied Physics of
  the Czech Technical University
• ELP GmbH, Wuppertal, Germany

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Objectives

• The paper presents a review of special optical
  research infrastructure developed for analyses of
  historical objects and materials.
• I often say that when you can measure what you
  are speaking about, and express it in numbers,
  you know something about it but when you cannot
  measure it, when you cannot express it in
  numbers, your knowledge is of a meager and
  unsatisfactory kind. Lord Kelvin (1824-1907)
• We see only what we know. Johann Wolfgang Goethe
  (1749-1832)

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Optical methods in medieval mortars
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Coded Photometry Stereo
Encoded image
Reconstructed topography
Lab version of CPS device
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CPS evaluation of laser cleaned surfaces
Reconstructed Topography (not the same scale as
SEM)
SEM micrograph
Visual
Topography
Enhanced visual
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Experimental application of CPS
Principal strain ?2 field
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Cuneiform tablet by CPS
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Cuneiform tablet by CPS
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Optical methods - Quantitative measurement

• a quantitative analysis of surface by optical
  method
• variable reflectance
• simple photometry portable scanner
• accompanied by a survey (carried on 10 selected
  buildings in Prague, for every building in
  average 50 persons)

cleaned
encrusted
Mean160
Mean210
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Optical methods - Quantitative measurement
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Optical methods - Quantitative measurement
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X-ray diagnostics
X-ray source fresco
Flat recording plates
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X-ray diagnostics
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Computer micro tomography

• X-ray tungsten micro focus tube Hamamatsu
• X-ray emission spot of 5 µm and divergent cone
  beam
• a magnification up to the micrometer scale in
  spatial resolution
• spatial resolution a half of the spot size
• the recognition resolution are a quarter of the
  spot size

Calibration carousel
X-ray source
Turntable shown with loading device and CPS
lights
Medipix detector (not visible)
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Computer micro tomography
Medipix2 (Near field)
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uCT - Bulk visualization
Concrete specimen (2x7x13mm)
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Conclusions

• A simple inventive adaptation of existing optical
  method can yield interesting results which cannot
  be obtained other way.
• But not only advantages optical methods are key
  to success, it is the whole infrastructure, which
  has to be understood in broader sense.
  Infrastructure is in addition to sum of
  equipments, devices and existing methods, a team
  of skilled experienced people coming from various
  scientific fields working together on innovative
  implementation of ideas and procedures in new
  applications. Therefore adequate interdisciplinar
  composition of the research team is an important
  element of working/functioning infrastructure.
• As demonstrated on above described examples it
  seems that these methods sophisticated and yet
  simple can be indispensable for research in the
  field offering results impossible to obtain by
  other means.
• Unfortunately investment into such methods hit a
  blind spot of research funding system are too
  costly and therefore behind reach of an institute
  to finance it using only its own resources and,
  at the same time, to small to be given attention
  of decisive funding agencies.

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Thank you acknowledgment

• EVK4-2001-00091 On-site investigation techniques
  for the structural evaluation of historical
  masonry buildings ONSITE-FORMASONRY, 2002-2004,
  5. FP EC, contract partner
• EVK4CT200230011 Intelligent Measurement
  Technology for Laser Cleaning of Historical
  Buildings and Monuments HISTO-CLEAN, 2003-2004,
  5. FP EC, contract partner
• Project NSF INT-0122251, U.S.-Czech Engineering
  Research In-Situ Evaluation of Historical Wood
  Buildings, 2001-2004, Czech part under KONTAKT
  ME660 Grant Ministry of Education (NSF contractor
  North Carolina State University)