hul 2004
"A
DEVELOPMENT AND APPLICATION OF THREE DIMENSIONAL
MEASUREMENT SYSTEM FOR TOROPICAL RAINFOREST CANOPY
M.Yoshimura * ,M. Yamashita?, T. Nakashizuka *
* Research Institute for Humanity and Nature, 335 Takashima-cho, Kamigyo-ku, Kyoto 602-0878, Japan
(yosh, toron)@chikyu.ac.jp
° Survey College of KINKI, 1-5-9 Yata, Higashi-Sumiyoshi-ku, Osaka 546-0023, Japan - yamashita@kinsoku.ac.jp
Commission VII, WG VIU2
KEY WORDS: Ecosystem, Forestry, Measurement, Reconstruction, Laser scanning, Surface, Three-dimensional
ABSTRACT:
As the most basic knowledge of remote sensing, spectral radiances that are reflected from the surface and received by the sensor are
under the influence of various physical factors. One of the most important factors is the reflectance properties of the surface such as
spatial, spectral and biophysical conditions. On the other hand, Tropical Rainforest is known as the most important for us to sustain
the global earth environment. However it is impossible to reach its canopy top because of their tall height. Recent years some of
canopy access systems such as walk way and crane appeared in the world. This kind of canopy crane can provide use good
opportunities to know the mechanisms of atmosphere-ecosphere interaction.
From the above background, we used the tropical canopy crane system with 80m height and 75m arm length as our measurement
platform, and developed the three-dimensional canopy structure measurement system by laser scanning system. One of main
purposes of this study is to identify three dimensional canopy surface structures. Our used laser scanning system, which we
developed, is integrated system with Global Positioning System, non-prism based laser scanning system and related technologies
instead of traditional photogrammetric techniques. The laser scanning system, which is loaded on the gondola of crane, is introduced
to the every measurement point by the manipulation of the arm swing and gondola moving. Both of monitoring system of the crane
and Global Positioning System (GPS) estimate each measurement point where we are. Furthermore the Digital Surface Model
(DSM) for tropical canopy was generated from the obtained three-dimensional data. This kind of information could provide the most
common and important knowledge for multi-disciplinary scientists in order to know the tropical canopy.
1. INTRODUCTION information not only for our own research but also for multi-
disciplinary researches related to ecology and meteorology.
Our research site is the tropical rainforest in Lambir hills From the above background, we had developed the laser
national park and the western part of Sarawak state, Borneo scanner based measurement system for identifying the three
Island, Malaysia. Figure 1 shows the location of our research dimensional tropical rainforest canopy structures and applied
site in Southeast Asia. This region is known as the typical the measurement results in order to generate canopy DSM and
tropical weather region without seasonal change. The tropical re-construct the virtual tropical rainforest. One of most
rainforest also is known as the lug of the earth or the treasury of important purposes is to provide an actual canopy structure as
biodiversity. Most of important processes of a tropical common data for multi-disciplinary usages.
rainforest are taking place at canopy layer. Canopy is the place
that trees make photosynthesis and transpiration, thus gas —R
exchange between ecosystem and atmosphere could not be -—
detected without studying the process in/on the canopy. At the
same time, the canopy is the place of interaction among many
organisms. And the canopy surface is the observation target of
remote sensing. However we do not know much about their
nature yet.
On the other hand, in order to estimate the surface physical
properties by remote sensing, it is necessary to gather the
atmospheric, climate, sun conditions and reflectance
characteristics at the target area as the basic information in the
same time as the satellite over passing. The authors have been
conducting the scaling up research of physical properties related
to forest ecosystem functions based on the ground based
measurements. At the beginning of our research, we only
wanted to know the spectral radiances that are reflected from
the surface and received by the sensor at tropical rainforest
canopy as the basic knowledge of remote sensing. Actually an
incident solar irradiance, atmospheric, meteorological, sensor
viewing conditions and reflectance properties arc the basic
Ix
Lambir Hills Naßiö
- Sarawak, Bor
sj
divi ane
Figure 1. Lambir Hills National Park as Our Research Site
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