5.2 Design of the Measurement System
63
Fig. 5.3 A MX-2010-G
topography meter used in a
concrete landslide
experiment. Keys: 1. Laser
source; 2. Camera with a
collimator; 3. Positioning
device with a spot laser;
4. Bracket; 5. Conceptual
model slope with navigation
dot markers and equidistant
projected fringes
1
2
4
1-2 m
5
3
m
3
Before the commencement of any slope behavior survey, we should adjust the
camera and make its sightline perpendicular to the laser planes using the sight calibrator. The calibrator was a
-shaped open container with three opaque walls, as
shown in Fig. 5.4. A group of parallel black lines spacing apart by a distance of 3 cm
were drawn on the transparent wall of the box. A reflecting mirror was set at the
bottom of the prismatic box. The operator held the sight calibrator under the camera
of the topography meter as the calibration experiment began. Then the parallel laser
planes were shot to the open mouth and projected onto the three walls. Meanwhile,
the laser lines from the collimator were thrown on the mirror at the bottom of the
sight calibrator. When the laser plane was perpendicular to the camera sightline, the
footprints of the laser plane were overlapped with black lines of the barrel wall,
and the spot lines from the collimator were directly reflected back to the collimator.
The calibrator could accurately examine the sight direction. Nevertheless, manipulating the calibrator could be difficult because the operator had to hold it. If a trestle
was designed for the collimator in the future, the operation would become more
convenient.
5.2.3 Structure of the MX-2010-G Topography Meter
The laser source was mounted on a rugged pedestal (Fig. 5.5), including the line
laser modules, module fasteners, a girder, and a cover. The line laser modules, also
63
Fig. 5.3 A MX-2010-G
topography meter used in a
concrete landslide
experiment. Keys: 1. Laser
source; 2. Camera with a
collimator; 3. Positioning
device with a spot laser;
4. Bracket; 5. Conceptual
model slope with navigation
dot markers and equidistant
projected fringes
1
2
4
1-2 m
5
3
m
3
Before the commencement of any slope behavior survey, we should adjust the
camera and make its sightline perpendicular to the laser planes using the sight calibrator. The calibrator was a
-shaped open container with three opaque walls, as
shown in Fig. 5.4. A group of parallel black lines spacing apart by a distance of 3 cm
were drawn on the transparent wall of the box. A reflecting mirror was set at the
bottom of the prismatic box. The operator held the sight calibrator under the camera
of the topography meter as the calibration experiment began. Then the parallel laser
planes were shot to the open mouth and projected onto the three walls. Meanwhile,
the laser lines from the collimator were thrown on the mirror at the bottom of the
sight calibrator. When the laser plane was perpendicular to the camera sightline, the
footprints of the laser plane were overlapped with black lines of the barrel wall,
and the spot lines from the collimator were directly reflected back to the collimator.
The calibrator could accurately examine the sight direction. Nevertheless, manipulating the calibrator could be difficult because the operator had to hold it. If a trestle
was designed for the collimator in the future, the operation would become more
convenient.
5.2.3 Structure of the MX-2010-G Topography Meter
The laser source was mounted on a rugged pedestal (Fig. 5.5), including the line
laser modules, module fasteners, a girder, and a cover. The line laser modules, also