Archives de catégorie : Surface 3D

ARTICLE : Surface 3D, X-Rays and X-tomography for museum object analysis in France

Article publié au

Symposium international [Diagnostic non destructif des biens culturels] commémorant 10e anniversaire du Centre de science de la conservation du patrimoine culturel, Corée, 2019

Clotilde Boust, Elsa Lambert, Charlotte Hochart, Nicolas Mélard, Benoit Mille, Center of research and restoration for French museums -C2RMF, 14 quai Francois Mitterrand 75001 Paris France

ARTICLE : 3D SURFACE ACQUISITION: COMPARISON OF TWO MICROTOPOGRAPHIC EQUIPMENTS WHEN MEASURING MATERIALS OF CULTURAL HERITAGE

4th CIE Expert Symposium on Colour and Visual Appearance, Prague 2016 http://www.cie.co.at/publications/proceedings-4th-cie-expert-symposium-colour-and-visual-appearance-6-7-september-2016

Page, M.J. (1,2,3) , Boust, C. (2) , Mélard, N. (2) , Robcis, D. (2) , Obein, G. (3)
1) Océ Print Logic Technologies, Créteil, FRANCE
2) Centre de Recherche et de Restauration des Musées de France, Paris, FRANCE
3) Conservatoire National des Arts et Métiers, Saint-Denis, FRANCE

roughness measures with Hirox microscope

Abstract
Surfaces of materials from cultural heritage are exceptionally varied as patina, varnish, wear or scratches are added intentionally or with time to the base material, whether it is wood, marble, stucco, or brass. Measuring their texture provides a lot of information to curators but it constitutes a challenging task for the engineer. The present study focuses on the question of texture acquisition by means of two optical micro-topographic instruments. As those
instruments deeply differ in their working principle, it is necessary to check if results are comparable in terms of roughness. Moreover, in order to define the space of materials they are able to record, the study highlighted how the global appearance of an object interferes
with the measurement of its surface relief, because of the design of the utilized instruments.


Keywords: Optical metrology, 3D, Appearance, Roughness, Cultural heritage, Scientific techniques in conservation and restoration


Appearance Reproduction for Cultural Heritage Applications: from Surface Acquisition to Realistic 2.5D Printing

Article de la thèse de Marine Page, publié à Electronic Imaging 2017 (http://www.imaging.org/site/IST/IST/Conferences/EI/Symposium_Overview.aspx)

M. Page 1,2,3 , C. Boust 1 , G. Obein 3 , M. Ortiz 2 , A. Razet 3

1 Centre de Recherche et de Restauration des Musées de France
2 Océ Print Logic Technologies
3 Conservatoire National des Arts et Métiers

Abstract
2.5D printing is a technology which creates surface relief by
superimposing successive layers of inks. The question of the
characterization of heights obtained with this technique brings us
to consider new metrics and mathematical ways to represent the
influence of diverse printing parameters on the obtained relief,
possibly used to compensate the defaults of the system.
Our method takes over the classical Modulation Transfer
Function (MTF) approach and adapts it to a vertical modulation
instead of considering the (x, y) plane, introducing then a Height
Modulation Transfer Function (HMTF). Characterization charts
are composed of lines patterns printed at different heights,
frequencies and droplet levels. Prints are scanned with a
chromatic confocal sensor and resulting topographies are
analyzed to extract the HMTF. By analogy with traditional MTF
methods, results – consisting of the measurement of the deviation
between the digital input and the analog output – allow to evaluate
the quality of our printer and to compensate it by setting up a
retro-action loop.
The method, here presented in the case of the 2.5D printing
prototype, can be extended to regular 3D printing techniques.