Keywords: Three-Dimensional Structural Data, Biomass, Grass Height, VCR
Abstract We measured the three-dimensional structural data of vegetation by using
the three dimensional scanning system (TDS). And we investigate the use of these thre
e-dimensional structural data of vegetation. For example, we estimate the dried weight of
vegetation (biomass) using three-dimensional data. In August, 1999, we made observatio
n in Mongolia grassland. And compare these data.
1. Introduction
It is very important to estimate the appearance of vegetation on the earth by using th
e low resolution satellite. And for the estimation, it is need to measure the dried-weight
(biomass) of plants.
In these years, we have made observations of Mongolian grassland. The methods of o
bservation are Mobile measurement, BRDF measurement, Radio controlled helicopter mea
surement, and Biomass measurement. In biomass measurement, we measure the grasses b
y dried weight, grass height, and cubic volume. And last year, we appropriate the thre
e-dimensional scanning system to acquire the three-dimensional structural data of plants(s
ee Fig.1). Three-dimensional data of grassland vegetation is useful when measure these b
iomass data. We develop the three dimensional scanning system and estimate bioma
ss data.
In August, 1999, We made three-dimensional measurement in Mongolia grassland. And
estimated the biomass using three-dimensional structural data of plants.
2. Three-Dimensional Scanning System
For the measurement, we use the three-dimensional scanning system(TDS-3100), produ
ced by PULSTEC industry.
The Three dimensional scanning system consists of three parts, a camera, controller an
d PC. The camera measures the distance from an object by using a laser scanning. The
laser is controlled by the PC and Controller (see Fig.2). The system shown in Fig.1 is
employed at the Mongolian grassland site to acquire three dimensional plant structure.
The characteristic points of this three-dimensional scanning system are follows:
- Non-destructive, non-touch measurement
- The wavelength of this laser is 680nm, and it is absorption band of vegetation.
- Small and easy to use.
3. Measurement
3.1 Measurement Area
We made some areas at measurement area in grassland near the camp site(Fig.3). The
camp site was set at the North part of Mandalgobi. Mandalgobi is seated at 250km far
from Ulaancaatar
(N25
° 59
^ 42"
E106
° 19' 40").
3.2 Measurement System
Measurement system is shown at Fig.4. Camera was set at the top of intelligent arm.
And take the three-dimensional data as intelligent arm moving, The intelligent arm is
produced by MITSUBISHI HEAVY INDUSTRY.
And setting this measurement system on the mobile car. (see Fig.5)
3.3 Measurement Method
We made some small areas(quadrat) in the measurement site. The size of one quadrat
is 1m .1m, and we made 16 quadrats. At the each quadrat, we have three-dimensio
nal measurement and biomass measurement. The three dimensional measurement was ma
de from four different angle, and each measurement was held three times for each quadr
at.
