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3D visual information and GIS technologies for paintings’ documentation in the M Sepulchre in the Vatican Necropolis

 
Introduction

The Vatican Necropolis 

The M Sepulchre

Microtopographic survey

3D Arm

Thermal Infrared Analysis

GIS

VRML

Gradoc index

 


 
Thermal Infrared Analysis

The Sepulcher model so far created was, used to map the information gathered during a thermal infrared scanning analysis carried out on the frontal (North) wall of the Mausoleum.
To insert the infrared imagery and the result of its processing into our 
metrically correct representation of the wall, a series of marks, visible both in visible and thermal infrared bands, were placed on the surface and surveyed.

The thermal infrared scanning was carried out with the Marconi TICM II, a high resolution system, operating in the 8-13 micron wavelength range.

The images were processed through dedicated software by MEDIA CYBERNETIC, applying the appropriate filters to enhance readability.

In the example image above (rendered in pseudo-colours), captured during the cooling phase, we see a presence of warmer areas (yellow-red) which correspond to possible slight detachments of the plaster layer from the brick surface. The cooler (blue) areas indicate the presence of a humidity front

.

By processing the infrared image, we can produce thematic maps and in this particular case we have recorded and outlined the above mentioned areas.

 This is an example of how it is possible to integrate analysis data into graphic documentation through the use of surveying methodologies.
  • The image rectification marks were surveyed with the same total station used in the surface acquisition process
  • The result has been the production of metrically accurate thematic 2D maps
  • The question is: would it be possible to go one step further and integrate the analysis mappings onto a 3D model?
  • There is no difference whether the mapping is done with ortho-images of the real surface or with images obtained through short range remote sensing techniques (thermal infrared images in our case), as long as they are metrically correct and referenced to points actually lying on the examined surface and appropriately surveyed. So the answer to the above question would certainly be yes.
  • What would the usefulness of such a step be? In our particular example the association of the humidity front with the shape of the underlying structure could offer a vast array of information which could not be fully appreciated through a simple 2D visualization. 
The examples in this sense could be innumerable. It is the conservator's task to imagine all the applications. All that a documentalist can say is that technology is offering new and extremely powerful tools capable of not only simplifying the documentation process but enhancing its results in ways we can't even yet imagine.