Geoscience Reference
In-Depth Information
Fig. 13 Range residuals as a
function of adjusted range for
the adjustment without
calibration parameters
0.02
0.01
0
-0.01
-0.02
0
5
10
15
20
Adjusted Range (Meter)
Fig. 14 Horizontal angle
residuals as a function of
adjusted vertical angles for
the adjustment without
calibration parameters
0.04
0.02
0
-0.02
-0.04
-50
0
50
100
150
200
250
Adjusted Vertical Angle (
°
)
Fig. 15 Vertical angle
residuals as a function of
adjusted horizontal angles for
the adjustment without
calibration parameters
0.04
0.02
0
-0.02
-0.04
0
50
100
150
200
Adjusted Horizontal Direction (
°
)
been made between true and measured values of scale bar. The scale bar analysis
has indicated that test points produce via photogrammetry technique have
0.06 mm accuracy which is appropriate to be considered as true values in this
study.
In contrast with the hybrid scanner, the residual patterns from a panoramic
scanner bundle adjustment can be used to detect the systematic error trends. As a
result, other than statistical analysis, residual patterns are also used in this analysis.
After performing the bundle adjustment process without any calibration parame-
ters, residual patterns were plotted as a function of the adjusted observations as
shown in Figs.
13
,
14
and
15
.
Based on the sample of residual patterns shown in Fig.
7
, all significant sys-
tematic errors have been investigated. There are no indications of systematic errors
existed for horizontal direction and vertical angle measurements (Figs.
13
and
14
,
respectively). Nevertheless, a trend like incline line has depicted in the residual
graph of range measurement, which indicates the existence of rangefinder offset
error. According to the results obtained in Table
1
, magnitude of errors for hori-
zontal direction (e.g. b
0
and b
1
) and vertical angle (e.g. c
0
) are very small. This has
become the main reason for no indications of errors can be identified in the
previous plotted residual graphs (Figs.
13
and
14
).
