The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Voi. XXXVII. Part Bl. Beijing 2008
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original data points were not filtered and there were some
noises on the region of landslide, the result did not obviously
show the change. From the Figure 6, the middle of the image is
the area of landslide, and there are obvious noises around
it .These noises cover the really circumstance of the landslide,
so it should be filtered above all.
Figure 4: The overlapping of the twi -scanned data points.
Figure 5: The result of visualizing comparison results as colors
mapped.
The point cloud is processed by Terrascan to remove the noises.
Terrascan can manage the lidar point cloud. For one thing, it
should convert the format of the data to suit the Terrascan
software. And then, the noises in point cloud are removed
(Terrasolid, 2004). Figure 7 shows the overlapping 3D image
of the simulated test of landslide. It can be easily distinguished
the change position and the shape of tested person.
After the data processing, noises and vegetation points were
filtered. In Inspect module of Polyworks, the point cloud were
compared to reference object or other objects in certain
direction and inspected the change of position. It can get the
direction and grade of the landslide by computing the 3D
variety. Figure 8 shows colored vectors attached to an object
along the direction of the landslide. According to the fact, it
can analyze the certain direction of change state such as X axis,
Y axis, Z axis or other direction to specify by yourself. In this
test, the tested person moved along the Y axis direction, so the
simulated landslide is along the Y axis and the vector direction
is Y axis. From the four images of Figure 7 and 8, the test
result is that landslide monitoring by ILRIS-3D based-ground
Figure 6: The TIN display of the overlapping twi-scanned data
points.
Figure 7: 3D visualizing of data points overlapping
(the first is a profile display, the second is a face display)
