2. Japanese earth resources satellite-1 (JERS-1)
JERS-1 is a remote sensing satellite designed to gather image
data which are useful to explore earth resources. It will be
launched in 1992 in Japan. Its:weight is- 1.4. tons and the
altitude of its orbit will be 568 km.
JERS-1 has two kinds of imaging systems. One is synthetic
aperture radar (SAR) and the other is optical sensor. The
wavelength of SAR is L band and the resolution of SAR image
is 19 m. The swath width“ of both. sensors is (75 km. The
ground resolution of optical sensor is 18.3 mx 24.0 m for
the nadir looking sensor and about 19.1 m x 24.0 m for the
forward looking sensor. The nadir looking sensor stakes
seven band images ^in the wavelengths of visible, near
infrared and shortwave infrared. The forward looking sensor
takes one band image in shortwave infrared wavelength.
The combination of a nadir looking sensor image and a forward
looking sensor image produces stereoscopic vision. The
base-to-height ratio of JERS-1 stereoscopic images is fixed to
0.3. This ratio can not be enlarged because the nadir looking
sensor and the forward looking sensor must be placed in the
same telescope due to considerations of weight limitations etc.
3. Development of a system to make JERS-1 simulation
stereoscopic images.
We developed a system to make JERS-1 simulation stereoscopic
images from photographs by computer. The quality and
usefulness of JERS-1 stereoscopic images can be investigated
using the output of this system. Figure 1 shows the general
flow of this system. The details of the components of this
figure will be explained next.
LFC photo. (Large Format Camera photo.)
The input image data of this system is photographic, parti-
cularly by LFC photograph taken from the space shuttle. LFC
photograph is very suitable for this system because it
covers a very large area with high ground resolution (about
15 ^ 20 m) similar to JERS-1 stereoscopic images. Moreover
a photograph has another merit in that the image distortion
of a photograph can be corrected more exactly than that of a
satellite image.
Digital image
The input LFC photograph is converted to a digital image by
drum-scanner.
Exterior orientation parameters
The exterior orientation parameters are extracted from a
positive-film of the LFC photograph using the aerotriangulation
method.
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