CIP A 2005 XX International Symposium, 26 September - 01 October, 2005, Torino, Italy
746
AUTOMATING THE EXTRACTION OF REVOLUTION OBJECTS FROM SINGLE
LASER SCANS OF ARCHITECTURAL SCENES
M. Deveau, G. Letellier, N. Paparoditis
Institut Géographique National, Laboratoire MATIS, 2, 4 avenue Pasteur 94165 Saint-Mandé Cedex
matthieu.deveau@ign.fr, guillaumeletellier@free.fr, nicolas.paparoditis@ign.fr
KEY WORDS: scanner laser, 3D Reconstruction, surface of revolution, profile estimation, range image
ABSTRACT
This paper focuses on the reconstruction of surfaces of revolution. We propose a method for estimating those surfaces from point
clouds. We are more particularly dealing with data coming from one unique laser scanner acquisition; indeed, our approach
extensively uses the range image topology. It makes originally use of geometric properties of surfaces of revolution. We firstly get an
approximation of the axis of revolution, thanks to a Hough transform of symmetry axis computed on range image contours. Robust
and accurate axis estimation refinement of position and orientation is then reached by minimizing the rms error of the profile
estimate. Image topology is also used to estimate the object’s profile. 3D points are connected following the image topology and the
nearest neighbouring planes rotating around the axis of revolution. After projection on these planes, lines connecting points allow
easy profile estimation. This method solves the measuring noise issue which is usually sorted out through moving least squares
solutions. Once the object of revolution has been reconstructed, we retrieve automatically all occurrences of this pattern in the scene,
with a scale adaptative matching algorithm.
1. GENERAL CONTEXT
The ARCHIPOLIS project, from the MATIS laboratory of the
Institute G éographique National (IGN), is dealing with high
scale city model reconstruction. A general strategy is proposed
combining aerial and terrestrial high resolution stereo imaging
on streets and fac.ades and dense laser and image acquisition on
main cultural heritage buildings. Complementarity and
continuity with aerial building reconstruction methods is also
studied (Paparoditis et al., 2005).
In this framwork, detailed reconstruction of cultural heritage
buildings from laser data and image is the scope of this paper.
Architectural scenes reconstruction of great heritage value is
especially important to reach a realistic representation. In this
context, one goal is to get a compact structured surface repre
sentation, with a high geometric accuracy. We aim metrological
applications for architects and surveyors, for restoration purpose
and archiving.
As cultural heritage buildings have got more complex structures
than apartments blocks, photogrammetry leads to long surveys,
that much longer than architecture is complex. On the other
side, laser scanners bring quickly a dense geometrical
information on complex parts. In this context, we are studying a
methodology using both laser data and image to ease
segmentation and reconstruction (Deveau et al., 2005). In this
article, we consider the segmentation part achieved and deal
with the reconstruction part of/on one specific structure: the
Surface Of Revolution (SOR), caracterized by its profile and its
axis of revolution. In this article, which reports our first works
on this field, only laser data are considered to achieve
reconstruction while image is only used for texturing.
1.1 Related works
Many solutions for the reconstruction of SOR have been pro
posed and are still studied. Many of them deal with a single
perspective view, either calibrated (Gr "un, 1975) (Wong et al.,
2002) or uncalibrated (Utcke and Zisserman, 2003) (Colombo et
al., 2005) and from silhouette’s contours. (Neviata et al., 1995)
have proposed methods of estimating generalized cylinders
from multiple images. Other ways of looking for SOR
reconstruction have followed the growth of range measuring
systems (Pottmann et al., 2002) (Willis et al., 2001). These
latter approaches have the drawback to lead to non-linear
system minimization.
1.2 Data characterization
We make use of the range image and the intensity image, the
latter coming from the backing laser intensity measure and
belonging to the same image geometry as the range image
(figure 1.2). Objects we are considering are usually scanned so
that more than one thousand points lie on their surface. Intensity
range is spread out on 8 bits. Standard deviation noise on
distance is calibrated to 2 mm at 10 m (scanning conditions
used for our experiments).
Figure 2: High resolution image.
2. EXTRACTING THE OBJECT SILHOUETTE
The SOR object is generally bounded by discontinuities which
are well characterized both in the range image and in the
intensity image. And because the SOR bounds symmetry
around axis of revolution is kept in the range image, a first axis
estimate can be solved.
We use a Hough transform on contour points coming from a