Geoscience Reference
In-Depth Information
(c
)
(a)
(b)
(d)
(e)
(f)
Fig. 5 Top Types of laser beam deflection units used in TLS. Bottom classification of TLS based
on field of view (Reshetyuk
2009
)
vertical FOV (Fig.
5
f) compared to hybrid scanner. Using the same mechanism as
hybrid scanner which is based on servomotor, this scanner is also capable of
providing 360 horizontal FOV. These advantages (360 horizontal FOV and
nearly the same for vertical FOV) has made panoramic scanner very useful for
indoors scanning.
3 Geometric Model for Self-Calibration
Due to the limited knowledge regarding the inner functioning of modern terrestrial
laser scanners, most researchers have made assumptions about a suitable error
model for TLS based on errors involve in reflectorless total stations (Lichti
2007
).
Since the data measured by TLS are range, horizontal and vertical angle, the
equations for each measurement are augmented with systematic error correction
model as follows (Reshetyuk
2009
):
Range
;
r ¼
p
x
2
þ
y
2
þ
z
2
þ
Dr
ð
3
Þ
þ
Du
x
y
Horizontal direction
;
u ¼ tan
1
ð
4
Þ
