International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B5. Istanbul 2004
considering the generated camera parameters and randomly
modified itself within their a priori standard deviation (4).
Starting point
| (systems time)
srand() Step 1
Generation of Random Numbers às a
pre-process for simulation Swp 2
RANDOM NU
random value [0.Rand MA
uniform random values [
Gl = rand():
RNG2
DOLL
7 te
BOX-MULLER Transformation
|
| input: uniform distributed (gRNGI, gRNG2)
| output: normal distributed (nRNGI, nRNG2)
Y
Y
For each image of the Input bundle for one simulation |
Step3 |
vi (exe Ye ApA A Á
/ BB C. /
# to be modified in quoted order /
T
{
| Randomly modified (rm) camera parameter
| e.g. ¢ (m) = ¢ + (NRNGI * 5.)
Further camera. YES
< parameters to reer
s
7. be modified? |.—
Y NO
Calculation of image coordinates of one |
image (standard observation equation) |
+
A dans Allowance of image |
^ Randomly 7, xS a age]
T : i YES coordinate due to
Pa 5 =
«o allowance with > ; :
T EON higher spread of
respect to r^ 2 - x
NS a rad.sym. dist. for. |
ied E ——— Re —
ye LT
| Randomly allowance of image en = |
i coordinate x.y" = f(s.)
t 1
j
Figure 3. Flow chart of simulation data generation for one
image / of one simulation process S
Consideration of higher deviation of radial-symmetric
distortion with respect to radial distance
The radial-symmetric lens distortion Aj, A», A5 considers the
highest influence of the distortion parameters. Due to its
functional definition (5)
202 dw
Artz ra n -üy e A, ft th Az A ) (5)
with r' - radial distance
rp = second zero-crossing
Ar' = radial-symmetric distortion
the standard deviation resp. its influence increases with the
radial distance like graphically shown in Figure 4 for the
following example (Table 1).
Kodak DCS 645 M — 35mm lens
Sensor format: 36.648 x 36.648 mm?
ck -35.6637 sck 0.0005
xh -0.0993 sxh 0.0007
yh 0.4083 syh 0.0007
Al -9.01 E-05 SA 1.56E-07
A2 6.23E-08 sA2 6.88E-10
A3 -1.48E-11 SA3 9.20E-13
Bl 2.37E-06 sB1 2.23E-07
B2 -1.46E-07 sB2 2.21E-07
C1 1.06E-04 sCI 3.30E-06
C2 -1.04E-05 sC2 3.17E-06
Table 1. Example camera paramter
radial distortion of standard deviation
UD16 4-—————— —-————-
{1.014 Sree
0.012
0.01
3 0.002
= 0.006
0.004
0.002
0+
3 10 15
radial distance [rur]
Figure 4. Standard deviation of radial-symmetric lens distortion
Applying this effect to the simulation process, an additive is
calculated for the concerning image coordinate. In order to
pursue the effect of the modified lens distortion with respect to
the superior input bundle parameter, the additive's sign is
generated of the difference of these two functional models. In
the following this modification is called RADVAR-
modification.
4. SIMULATION RESULTS AND ANALYSIS
The results and analyses are based on free-net bundle
adjustments (free camera geometry), restrictively with three
fixed scales placed to the coordinate systems axes. Because of
the random generation of data sets, different blunder might
appear due to an instable new data bundle. Modern bundle
programs like BUNDY (own development of our institute),
which is used for this simulation process, have integrated and
non-changeable blunder detection algorithms. Strictly speaking
the simulation results are based on different object geometry.
The importance of this effect does mainly appear when scale
points are eliminated within the calculation process, which
causes different scales in object space. Concerning the
following results and analyses these false-scaled bundle results
are eliminated. In the following the expression input value
defines the randomly modified values of the simulation process.
4.1 Camera geometry
4.1.1 Input values: With respect to the example of the
Kodak DCS 645 M (Table 1) the normal distributed input
values for principal distance and principal point result as shown
in the diagrams (Fig. 5,6). The principal distance input values
span from 36.66187mm to 36.66556mm. Regarding its standard
deviation sy = 0.0005mm, 0.4% of all values (200 simulations *
60 images per bundle) lie outside the triple standard deviation,
equally 0.4% of all values for the y-direction of the principal
Internati
point, w
with refc
Due to a
direction
outside 3
are frame
Figure 5
Figure
The dist
(hence 6
Figure 7.
yield to :
random
maximun
regarding
variation
The cor
coordinat
higher dc
to the re
essential.
dr nasi =
influence
41.2" |
at the out
correspor
demonstr
InputB v
example
input val
Prm) d