3D imaging applications for ancient wooden stamps analysis

R. Seulin1, F. Nicolier2, D. Fofi1, G. Millon2,C. Stolz1

1Le2i - CNRS UMR 5158, IUT, 12 rue de la fonderie, 71200 LE CREUSOT, FRANCE
E-mail: ralph.seulin@u-bourgogne.fr
2CreSTIC Laboratory, URCA, IUT, 9 rue de Québec, 10026 TROYES Cedex, FRANCE
Topical Meeting OSAV2004

1. ABSTRACT
This paper deals with the analysis of ancient wooden stamps. The aim is to provide tools for
historians to ease the manipulation of very fragile and unique objects. By performing first a
3D imaging of stamps, data are then processed into three different methods: 1) an adaptive
thresholding on the corresponding range image enables to obtain the unknown produced
illustration of the stamp, 2) an interactive enhanced rendering provides a realistic real time
visualization and finally, 3) a rapid prototyping production gives a perfect geometrical copy of
the stamps enabling a real risk safe manipulation.

Keywords: Cultural Heritage Conservation, Wooden Stamps, 3D Imaging, 3D Rendering,
Rapid Prototyping

2. INTRODUCTION
The Troyes's municipal library is rich in old documents and books series (years between 1500
to 1900) among the most important in French provincial libraries. The collection of 150 000
books includes 1700 medieval manuscripts, 700 incunabula, 2500 hawking booklets from
"Bibliothèque bleue" serie and about 800 engraved wooden stamps used to illustrate those
documents. This richness heritage led the Troyes's municipal library to join the Ancient
Document Digitization national program of the French cultural department since 1998. One of
the main problems involved in this program is to develop software and image processing
systems to allow efficient access to the documents1. This is the ANITA project (ANalysis of
ancient Images and sTAmps).

This article is focused on the analysis of ancient wooden stamps. A typical wooden stamp is
presented on Figure 1.

The main goal is to provide digital tools for researchers in book history for a suitable access
and manipulation of the stamps. For the moment, stamps access and manipulation is really
Figure 1 - Ancient Wooden Stamp

difficult because of the storage (stamps are stored in basements) and the fragility of the objects
(wood degradation). Our work is to develop tools able to acquire, handle, compare and
visualize ancient wooden stamps and illustrations produced by inking and using a printing
press with the stamps.
A non-contact method is being used to perform three main applications for the stamp analysis:
virtual stamping, visualization and duplication. In this article we first develop the used 3D
imaging techniques based on a portable 3D scanner. Each application is then described by
explaining how the 3D data are processed.

3. 3D DATA ACQUISITION
Two 3D scanners of the Le2i laboratory and Plateform3D have been used for this project.
These two apparatuses function according to the method of laser triangulation by projection of
a laser plane.

Replica 500 Scanner from 3DScanners©
This scanner is provided with a sensor head (made of a laser plane and two CCD cameras)
mounted on a 3 axes translation system. This scanner provides only point clouds. Figure 2
presents the system. The precision is 50 µm on the X and Y axis and 20 µm on the Z axis. The
useful working volume is about 500x500x500 mm.

VI-910 Scanner from Konica-Minolta©
This scanner is compact, portable and is able to function in an autonomous way (without any
associated microcomputer). It enables to capture the geometry and the texture of 3D objects.
The acquisition of the geometry is carried out by a rotary sweeping of the laser plane. The
acquisition of color texture is carried out by the capture of 3 images through red, green and
blue filters mounted on a wheel. Figure 3 and Figure 4 present this system.


Figure 2 - REPLICA 3D Scanner

Figure 3 - VI-910 Scanner Front
View

Figure 4 - VI-910 Scanner
Back View

The precision is of 100 µm on X, Y and Z axis. This system enables the digitization of 10 mm
to 1 m width objects.