across
al Data
GISs",
III/IV-
gn Of A
st". ITC
"Spatial
t/Server
ncouver
ing, A
ISBN
ti-Scale
ement”,
., 1993
perable
atabase
Systems
, David
ds), pp.
ts And
bases".
ystems,
|. 0-02-
1991:
graphic
derated
nt For
cales”.
s.
Support
“oncept
s, ITC,
ASSESSMENT OF THE POTENTIAL OF JERS-1 FOR RELIEF
MAPPING USING OPTICAL AND SAR DATA
Hannes RAGGAM, Alexander ALMER
Institute for Digital Image Processing, JOANNEUM RESEARCH
Wastiangasse 6, A-8010 Graz, AUSTRIA
Commission IV, Working Group IV/2
KEY WORDS: Cartography, DEM/DTM, Correlation, Rectification, Stereoscopic DEM/DTM Generation
ABSTRACT:
The Japanese Earth Resources Satellite-1 (JERS-1) is equipped with a multispectral optical sensor (OPS-VNIR) in
visible and near infrared as well as a microwave synthetic aperture radar (SAR) sensor. The optical sensor additionally
includes a capability for in-orbit acquisition of stereoscopic image data. This paper focuses on the geometric treatment
of JERS-1 image pairs, both from the optical and the SAR imaging mode. In general, the aspect of topographic
information extraction based on stereoscopic images is treated. The potential mapping accuracy is analysed for JERS-1
image pairs with regard to geometric modelling, stereo model set-up and relief mapping. These activities have been part
of the research project ,Assessment of the Potential of JERS-1 for Thematic and Relief Mapping Using Optical and SAR
Data“, which has been defined and accomplished by the Institute for Digital Image Processing in its role as a Principal
Investigator within the JERS-1 mission.
1. INTRODUCTION
The Japanese Earth Resources Satellite-1 (JERS-1) is
the first remote sensing satellite with a multisensoral
imaging capability, as it carries a multispectral optical
sensor as well as a microwave synthetic aperture radar
(SAR) sensor in L-band on board. The optical sensor
comprises 4 spectral bands each in visible and near
infrared (OPS-VNIR) as well as in short wavelength
infrared (OPS-SWIR).
The OPS-VNIR instrument can acquire in-orbit stereo
data as a combination of spectral bands 3 and 4. One
image of the stereo pair is represented by spectral band 3
(wavelength 0.71 - 0.91 um) of the JERS-VNIR sensor,
whereas its stereo partner, i.e. spectral band 4, is
achieved through simultaneous imaging of the terrain with
a forward looking sensor, the tilt angle being about 15
degrees. This imaging mode can be specifically used for
the extraction of 3D terrain information.
Based on optical and SAR image data acquired by the
JERS sensor various experiments related to relief
mapping have been carried out for the Otztal test area.
This area is located in the Austrian Alps and shows high
mountainous and partly glaciated terrain reaching from
about 1750 to more than 3700 meters above sea level.
The test site has been selected as the major test site
within the JERS-1 research activity ,Assessment of the
Potential of JERS-1 for Thematic and Relief Mapping
Using Optical and SAR Data“ of the Institute for Digital
Image Processing of JOANNEUM RESEARCH. Besides,
this test area has also been designated as a primary test
site for glaciological experiments within the SIR-C/X-SAR
671
mission and has been used within other investigations in
the field of geocoding or stereo mapping. Related work is
for instance presented in Almer et al. (1991) or Raggam
et al. (1991).
The work presented in this paper comprises the use of
JERS-1 optical and SAR image pairs in order to extract
topographic information stereoscopically. Based on inter-
comparison of achieved results and proper reference data
a thorough analysis of the quality of achieved results is
given.
The following JERS-1 image pairs have been considered
for investigations on their potential for relief mapping:
e a stereoscopic JERS-1 optical image being acquired on
August 18, 1992, with a nominal pixel resolution of 18
meters on ground. The respective image pair is
denoted as OPS-1 and OPS-2 in the following (see
Figure 1).
e a pair of JERS-1 L-band SAR images, being acquired
from 2 adjacent orbits on 22nd and 23rd of October,
1993 (denoted as SAR-1 and SAR-2, see Figure 2).
These images are acquired with a nominal pixel
resolution of 12.5 meters and an off-nadir looking angle
of about 35 degrees. The SAR-1 image, however,
unfortunately covers only a minor part of our area of
interest.
For the optical and the SAR image pair it was intended to
extract topographic relief using stereoscopic mapping
procedures. Therefore, preparatory processing and
analyses have been performed like geometric modelling
of the image data and investigation of monoscopic and
stereoscopic mapping accuracy.
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B4. Vienna 1996
