Fl
or
ent
POUX
(
1)
(
2)
&
Rol
and
BI
LLEN
(
2)
(
1)
Ecol
e
Supér
i
eur
e
des
Géomèt
r
es
et
Topogr
aphes
(
ESTGT)
,
Fr
ance
-
or
ent
poux@gmai
l
.
com
(
2)
Geomat
i
cs
Uni
t
-
Uni
ver
s
i
t
y
of
Li
ege
(
ULG)
,
Bel
gi
um
-
r
bi
l
l
en@ul
g.
ac.
be
Res
ul
t
s
:
a
pr
eci
s
e
aut
omat
i
c
s
t
r
uct
ur
at
i
on
of
di
ffer
ent
el
ement
s
of
any
s
cene
Concl
us
i
on
Thissegmentation isa really efficientmethod to extractdifferentelementsfrom a pointcloud to be considered,analysed and processed independently.We obtain a s eg-mented pointcloud thatrepresentselegantly the scene and make ita base fora worthy analysisand reconstruction.Thisapplication to promote culturalheritage transcend
whatexistnowadays,and becomesa new way oftransmitting history to future generations.
Segmentation of500 000 points,partofthe CathedralSaint-Paulpointcloud Segmentation ofa 1 Billion pointCloud representing the ColonsterCastle (Liège)
Val
i
dat
i
on
of
t
he
Segment
at
i
on
met
hod
Inuence ofthe similarity threshold (3)
Segmentation 1
(1) Segment(2)ation 2
1.Determination ofthe normaland curvature ofevery point
2.Region growing (1)grouping points with a similarnormal
3.
3.Relationship study (2)(connectivity, angle,size,symmetry,geometry)of every previousregion to create nal
segmentation
Inputparameters:
The similarity threshold:Difference bet -ween 2 normals.The closerto 0 itis,the more segmented the pointcloud willbe
((3):from leftto rightaugmentation of the parameter)
T
The search radius:Euclidean distance li -mitating the neighborhood search
Minimum detailextracted:Willadapt the size ofthe crosssection forthe relati
-onship study
The
Segment
at
i
on:
t
heor
y
&
al
gor
i
t
hm
A 2 Billion PointCloud acquired throughtmore than 65 stations
isa very complex dataset.The need to develop an easier,faster & automatic processto organize
& handle the amountofdata is essential
We wantto extractshapesforan archeologicalstudy on medievalconstruction outofa pointcloud acquired with a 3D Scannerlaser,representing the cathedralSt-Paulof
Liège.Considering the complexity ofthe monument,archeologicalsmeansto extract information are time consuming and notalwayspossible.The possibility to use the
e-xibility and the precision given by a 3D pointcloud istremendous.A large amountof differentgeometric primitivescan be found contrasting with the amountofdetailatt
a-ched to such a structure (and the precision involve),perfectto serve asa complex data ca
carriershowing the versatility ofthe post-processing algorithm
