- Home
- Conferences
- Conference Proceedings
- Conferences
GeoSiberia 2007 - International Exhibition and Scientific Congress
- Conference date: 25 Apr 2007 - 25 Apr 2007
- Location: Novosibirsk, Russia
- ISBN: 978-94-6282-090-6
- Published: 25 April 2007
61 - 80 of 506 results
-
-
-
-
Airborne laser scanning – high quality digital terrain modelling
Authors C. Briese, G. Mandlburger and N. PfeiferAfter a short introduction into the Airborne Laser Scanning (ALS), the sampling
process and a brief comparison of ALS with other data acquisition methods, the paper
focuses on the generation of high quality digital terrain models from ALS data. In the
first part the hierarchic robust interpolation method for the automatic filtering and
classification, respectively, of an ALS point cloud into terrain and off-terrain (points
on buildings or on the vegetation, etc.) is presented. Then, an approach for the modelling
of linear features, such as break lines, based on the ALS data is described. Based
on the feature lines and the classified terrain points a high quality DTM can be determined.
For many subsequent processes the data reduction of the detailed DTM is
essential in order to handle the large amount of data. Therefore, the paper presents a
data reduction method that guaranties a certain DTM representation quality. Next to
the presented algorithms, for each of the mentioned topics, references to other published
methods are provided. Furthermore, beside the description of the algorithms,
practical examples demonstrate the results of the algorithms. At the end of the paper,
an outlook section discusses the advanced possibilities of DTM determination based
on full-waveform ALS data.
-
-
-
Laser scanning – principles and applications
Authors N. Pfeifer and C. BrieseIn this overview paper the principles of laser scanning systems are presented.
This includes a survey of different range measurement principles as well as different
mechanisms for the deflection of the emitted laser beam. Furthermore, the usage of the
laser scanning (LS) principle at different platforms (airborne (ALS), terrestrial (TLS),
satellite) is discussed. Additionally, typical sensor parameters of currently commercially
available sensor systems are presented. Furthermore, the technique of full-waveform LS
is introduced and georeferencing of ALS data for improved precision is presented. The
usage of LS data in different applications will be presented in an overview.
-
-
-
Error budget of terrestrial laserscanning: influence of the intensity remission on the scan quality
Authors A. Bucksch, R. Lindenbergh and J. van ReeTerrestrial laser scanning (TLS) is a surveying technology to measure distances
to surfaces in the spherical surrounding of the scanner instrument. In contrast to
pulse, i.e. time of flight scanners, phase based scanners emit a modulated wave signal
that allows for determining the object distance from the returned phase pattern.
Because of their high scanning speed, phase based instruments are getting more and
more popular. It is clear from literature and practice that, because of the interaction
between the laser light and the object, the characteristics of the object surface have a
large influence on the measurement quality. Still, a quantitative insight in the quality
of scanning results is missing.
This publication will compare two phase based scanners, the Imager5003
from Zoller und Fröhlich and the HS880 from Faro. We investigate the scan
quality of both scanners for a variety of surfaces with different reflection
characteristics. For this purpose scans of an Esser Test Chart TE 109 were made
with both scanners. The test chart consists of six different grey patches ranging
from 71% remission white to 0.05% remission black. The chart was scanned
from a distance of 4 m in a stable environment. In order to compare the scanning
results of both scanners a patch wise analysis is made of (i) the number of points
scanned, (ii) the intensities values of the scanned points, and (iii) the reliability
and precision of a local plane adjustment.
It turns out that for both scanners the measurement noise is significantly
increasing with decreasing remission. An insight in the amount of absorbed and
reflected energy per grey value patch will be part of the analysis results. An overall
conclusion of the presented experiment is that the two scanners differ only in extreme
cases from the specifications given by the manufacturers.
-