it is expected that the system is mainly used in
areas where radio waves cannot reach. A vibration
gyro, whose performance was somewhat lower but
inexpensive, and a fiber optical gyro with moderate
performance were used. In addition, a servo-type
accelerometer was used. By installing the
individual unit of the gyros and accelerometer on
each of X, Y and Z axes that were orthogonal to one
another, inertial equipment based on a strap-down
system was prepared. A 2.11-megapixel digital
camera was used for the equipment. The authors
eventually would like to develop a mobile type ofthe
inertial photogrammetric camera system which
was developed in this study. In this paper, however,
as the basic stage for its development, a tripod for
the camera was installed on a cart with wheels and
both the inertial equipment and the digital camera
were mounted on the tripod. In addition, a personal
computer for data collection and an electric power
unit were mounted on the cart. À landslide area
subject to this study was about 60 meters in height,
the width of its lower end was about 100 meters,
and its oblique angle was about 50 degrees. While
moving the cart on a river bank that was located
about 120 meters away from the landslide area, the
stereo photographs of the landslide area were
taken. To examine the accuracy of measured
results obtained by the inertial photogrammetry, a
white polystyrene foam plate with a size of 80 x 80
cm was placed on several locations in the landslide
area. Those locations were then measured by a
Total Station and the obtained data were regarded
as the true values. Based on the photographs taken,
a topographic map (contour map) was prepared.
2 COMPOSITION OF THIS SYSTEM
In the system of the photogrammetry done with an
inertial device, a gyro and an accelerometer which
were installed at right angles to each other were
equipped with a camera in this study. Data from
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B5. Istanbul 2004
gyro and accelerometer is converted from
analogue into digital through the A/D conversion
board, and is taken into the personal computer.
Then, the position and the inclination of the
camera at the time of taking a picture are
calculated. On the other hand, the photograph
taken with the camera is measured using a
digitizer, and a analysis of the photograph is
performed in the position and the inclination of a
camera which were obtained from the gyro and
the accelerometer. Figurel shows the coordinate
system and sensor.
Accelerometer
e ER
X CD
Axis X Axis Y
Figurel. Coordinate system and sensor
2.1 Inertial device
(1) Vibration gyro: The vibration gyro used for
this measurement is the ENV-O5A piezo-electric
vibration gyro of Murata Mfg. Co. Ltd. which is
shown in Figure 2.
(2) Fiber optical gyro: The fiber optical gyro used
for this measurement is the JG-35FD fiber
optical gyro of Japan Aviation Electronics
Industry, Ltd. which is shown in Figure 3.
(3) Accelerometer: The accelerometer used for
this measurement is the JA-5V accelerometer of
Japan Aviation Electronics Industry, Ltd. which
is shown in Figure 4.
ar
in
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