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International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XL-5/W2, 2013 
XXIV International CIPA Symposium, 2 — 6 September 2013, Strasbourg, France 
2.3Protocols 
For each group defined by the typology, a protocol is proposed. 
It explains the work-flow, the critical parameters and at the end, 
it synthesizes it in a short procedure. 
For example, the protocol “all around a simple artefact” 
explains how to photograph an artefact with a simple 
morphology situated in an easy context (space around, textured 
background) in order to compute exhaustive point-clouds. 
The figure 2 shows the spatial configuration of the master 
images (in blue), of the associated images (in white) and of the 
intermediary images helping to connect all the image in the 
orientation (in green). 
   
Figure 2. Spatial configuration of the acquisition of an artefact 
with a simple morphology 
A morphology is said to be simple when it can be exhaustively 
observed from few points of view. In this case, a number of four 
master images are enough to digitize the whole superior part 
(the bottom can not be visible without moving the artefact). 
Each master image is associated with four images which offer 
vertical and horizontal multi-stereo. The ratio base to distance is 
circa one to ten and the overlapping as largest as possible. 
The photographs are taken with a small angle toward the 
support of the artefact. With such a spatial configuration, the 
artefact can easily (if it is matt enough) be lighted with a diffuse 
Zenith light: outdoor an overcast sky and indoor a studio flash 
with a big light box for example. 
The organization of the introduction explanations and of the 
different protocols is from general concepts to precise 
parameters. If the user of the pipeline really understands the 
concepts of image-based modelling, he can develop a practice 
and not just be dependent of a technology. 
After the first tries with a protocol, a photographer will 
probably adapt it to the artefacts he photographs and to the way 
he works. The round-trips between protocol applications and 
on-field experimentations make it evolve. 
Even for one group of artefact, there are several possibilities of 
digitizing it. This is why the pipelines have to be open: each 
photographer can develop his own practice. 
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3.WEB-INTERFACE: TEMPLATES AND RECIPES 
These protocols and the possibility of creating new ones are 
translated into the interface. It exists in two versions: one with 
different parameters for the users who want to develop their 
own processing, another simplified for the users who want to 
use a process template. 
Each template is developed for one protocol. It takes into 
account: 
* the data organisation (naming, function of each 
picture), 
* the mode of tie points computation and the resolution 
of the picture for this step, 
* if an auto-calibration is done or not, and on which 
photographs, 
* some parameters of the orientation (calibration,di 
stortion model, pre-orientation, bascule), 
* some parameters of the-dense image-matching (using 
of masks, regulation factor, etc.), 
* some parameters for the colorimetric equalization, the 
points cloud export and the meshing (image used for 
the texturing, regulation, etc.) 
Enough parameters are provided while keeping a user-friendly 
form. Therefore the interface stays simple enough to be rapidly 
understood. In addition its structure presents the different 
photogrammetric steps. It helps the user keep in mind the 
mechanism of the processing and take into consideration the 
photogrammetric constraints during the acquisition. 
4.PRACTICE ISSUES 
Which professionals are able to produce the quality photographs 
necessary for the 3D digitization? 
The photographers working in the cultural heritage field already 
should have the knowledge, the equipment and the 
communication skill to extend their practice to 3D digitization. 
As noted in part 2.1, a lot of parameters and constraints are 
linked one with each other. Managing the photographic 
parameters for classical shooting is a prerequisite to begin the 
practice of image-based modelling. 
Moreover a photographer already working with architects, 
curators or other professionals already has a sensibility with the 
objects he photographs and an ease to communicate about it. 
This communication is essential for the acquisitions 
specifications to be clear and the results, properly documented. 
Such professionals are the best-equipped and best-prepared to 
achieve optimal results. 
The Culture 3D Clouds project could represent a good 
opportunity for institutions that houses and cares collections of 
artefacts. This method provides the ability to create 3d models 
of artefacts without major investments, as no equipment nor 
recruitment of 3d expert are necessary. 
The main technical difficulty in the photogrammetric method is 
the data processing and that phase might require a specific 
technical expertise, which is very rare in cultural heritage 
institutions. To resolve this problem, the process used in Culture 
3D Clouds will be based on an online-tool for non-experts. Web 
service to create 3d model with photographs allows the 
utilization of photogrammetric method with a limited technical 
expertise and removes the need to install a specific software, 
train on it and maintain it. 
By separating acquisition and calculation phase, this process 
might give to the institution an easy way to create 3D models of 
digital artefacts with photographs that they still have the 
capacity to produce.