In: Wagner W., Szekely, B. (eds.): ISPRS TC VII Symposium - 100 Years ISPRS, Vienna, Austria, July 5-7, 2010, IAPRS, Vol. XXXVIII, Part7B
374
whose coordinates in both TWD67 and TWD97 were known,
were selected as check points.
By comparing the registered and the known coordinates of the
check points in TWD97 datum, an rms value for the coordinate
differences is of about 11 cm in both x- and y- coordinates
(Table 1). This indicates that the results of the registration
method developed here are satisfactory for the subsequent
application.
Difference
Ax(m)
Ay(m)
max
0.326
0.309
mean
0.048
-0.030
rms
0.109
0.110
Table 1. Coordinate differences of check points.
The quality of reconstructed building models is evaluated by
manual check. In Figure 5, a closed polygon represents a
building. Our results have shown that in total 34 of 108
buildings are incorrect building models showed with gray
polygons in Figure 5 using our automatic procedure.
Figure 5. Incorrect building models (gray polygons) in the test
area.
These incorrect polygons always arise on certain cases. These
cases can be divided into two categories: (1) Roof faces are
partly or fully covered by neighbouring buildings or trees, as
shown in case A in Table 2. (2) Building outlines are not
detailed enough, as shown in case B in Table 2. In cases B,
small buildings are inside a big building, but the outlines of the
small buildings are not drawn in the map. In all these cases,
boundary LiDAR points are not sufficient to match with
building outlines. This shows that these discrepancies between
the boundary points and the outlines of that building influence
the results of the reconstruction of building models. All of these
incorrect models should be refined manually, by
photogrammetry, or even field work, for instance. The complete
result of automatic reconstruction of 3D building models is
drawn in Figure 6.
Table 2. Fusion of LiDAR data and topographic map after
registration and the results of building model reconstruction.
Figure 6. Complete result of automatic reconstructed building
models.
5. CONCLUSIONS
This study has presented a novel method to construct building
models by fusing LiDAR data and topographic map information.
A procedure for registering the boundary points of building roof
patches extracted from LiDAR data and outlines of buildings
acquired from topographic maps has been proposed by a robust
least squares method.
The experiments have shown that the proposed method for the
building reconstruction procedure with LiDAR data and
topographic map information, including feature extraction,
registration and reconstruction, can be processed automatically
and yields good results. Although manual editing is needed in
order to achieve refined 3D building models, the results have
shown that our method takes advantages of both surfaces and
boundary information and improves the building reconstruction
process.
6. REFERENCES
Filin, S., 2002. Surface clustering from airborne laser scanning
data. International Archives of Photogrammetry and Remote
Sensing, 34(3A), pp. 119-124.
Filin, S., Y. Kulakov and Y. Doytsher 2005. Application of
Airborne Laser Technology to 3D Cadastre. FIG Working Week
2005 and GSDI-8, Cairo, Egypt.
Gruen, A. and D. Akca, 2005. Least squares 3D surface and
curve matching. ISPRS Journal of Photogrammetry and Remote
Sensing, 59(3), pp. 151-174.