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Close-range imaging, long-range vision

ering data sets using an
ry and machine vision
ical 3-D Measurement
Editors), Wichmann, pp
R.Tanaka, H.Yokoyama, H.Chikatsu
Tokyo Denki University, Department of Civil Engineering,
Hatoyama, Saitama, 350-0394, Japan
(01smg11, yokoyama, chikatsu)@g.dendai.ac.jp
nd Jones, T. W., 2002.
r a stretched-lens solar
Oth International Modal
fornia, U.S.A. Commission V, WG V/1
Surface characterisation
nference on Optical 3-D
d H. Kahmen (Editors),
KEY WORDS: Laser scanning, DEM, Three-dimensional, Automatic, Survey
orammetry at the NASA
dings, Symposium on
Jniversity of Melbourne,
Recently, ground based laser scanners have been receiving more attention as an useful tool for realtime acquisition of 3D data, and
its many applications were proposed in various fidds. In particular, scene modelling or visualization of landscape is expected since
point clouds data are acquired. Generally, total stations are used in topographic surveys, and traverse surveys are popular method as
topographic surveys. However, only planimetric map is obtained by traverse surveys. Therefore, it is expected 3D traverse surveys
5. Calibration of CCD
modes. Conference on
Sensing '95, SPIE Vol.
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ixed wing micro aerial
{ Atmospheric Flight
Eyre J. 1999. Vision
ualisation in structural
nmetric Record, 16(94),
which have ability to produce scene model using ground based line laser scanner.
With these motive, the authors investigated an efficient traverse survey system usng ground based laser scanning sensors, and visual
traverse system using ground based laser scanning sensor is reported in this paper.
Regarding topographic surveys, generally total stations are
used as a popular survey instruments. High accuracy does not
expected in comparison with total stations. However, ground
based laser scanners have advantage to acquire 3D data in real
time, furthermore 3D traverse surveys is expected using laser
scanners instead of only 2D planimetric map which is obtained
from popular traverse surveys.
With this motive, visual traverse system using ground based
laser scanning sensors is expected. There are some issues,
however, which resolved before the system may become
operational. The most bottleneck problem is to reduce noises
which are caused by trees, grasses, electric poles and so on.
Many filtering system for noise reduction were proposed in air
born laser scanning fields (H.Masaharu, 2000, K.Kraus, 2001).
These noise reduction methods are not so available to ground
base surveys since ground base surveys are often perform
limited area where is covered low tress and grasses.
This paper reports automatic noise reduction method and
interpolated method for the lack of 3D data, and shows the
DEM which was acquired
Figure 1 shows the flow of visual traverse system. This system
is consists of some processes. These processes are
measurement, noise reduction, interpolation, unification of
coordinates and visualization. Detail procedures for each
process are descried in afterward.

| Topographic Measurement

| Noise Reduction



Figure 1. Flow of Visual Traverse System
3D Laser Scanning Sensor (LD90-3100VHS-FLP, accuracy:
+25mm) was used in this paper. Distance, vertical angles and
horizontal angle to the objects, and the intensity for the objects
are obtained by the laser scanning sensor. The intensity is
shown the strength of the laser light reflection, and it changes
by the material of subject, distances to a subject and so on.
Furthermore, 3D coordinates are calculated using distances and
posture angles automatically.
Figure 2 shows sloping ground in the Tokyo Denki University.
The sloping ground was selected as a test site and was
measured by following condition. Vertical = 30 deg. (Mark
Num.: 167 points), Horizontal= 160 deg. (Mark Num.: 878
points), Composition Num. =150,000 points. Figure 3 shows
the intensity image.

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