International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B4. Istanbul 2004
3. STARIMAGER/TLS (THREE LINE SENSOR)
STARIMAGER/TLS (Three Line Sensor) is an optical
sensor for aerial survey. TLS is composed of three linear
CCD arranged in parallel, and it can acquire three images
of each direction (forward, nadir and backward) at the
same time as Figure.1 shows. The sensor is oriented on
an aircraft perpendicularly to flight direction and scans
the ground plane. Therefore, a triple stereo image of a
ground object can be acquired.
TLS images are ultra high-resolution (spatial resolution:
3cm) images, and it can acquire triple stereo images at
the same time. Additionally, TLS images have more
advantages such as less influence of occlusion and
information from roofs as well as walls.
Flight direction
Backward
Forward
Figure. 1. Method of getting data with TLS
4. EXISTING 3D DATA
3D building texture data, which is assumed as existing
data, are prepared beforehand. The data include not only
roof textures but also wall textures. If the data do not
exist, they can be generated from TLS images, which are
acquired at different time period than the TLS data for
change detection.
Additionally, 3D data with high representation are
required to refer textures in TLS images correctly in this
method. For example, Figure.2 shows a result of
overlaying low-level 3D data on a TLS image. As this
figure shows, the low-level 3D data cannot be referred
corresponding texture correctly.
bei
Figure. 2. Low-level 3D data
Figure. 3. High-level 3D data
Though many 3D data exist in urban areas, high-level 3D
data such as TLS-scale 3D data exist seldom. Based on
these, we have developed the snake-aided 3D data
refinement method for this processing [1]. The
followings show examples of the SNAKE-aided 3D data
refinement (Figure.4-Figure.6).
SM UE. : : pes,
Figure. 5. Refined 3D data
Figure. 6. Refined 3D data
5. CHANGE DETECTION
Therefore, high-level 3D data must be prepared such as
Figure.3. Urban dense areas have various sizes of buildings.
Therefore 'coarse change detection? and ‘fine change
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