tion
ite,
"of
cion
are
rior
sas.
| as
nal
J to
ing
tion
AP’ 5
tion
only
ting
rder
Equation (1) and (3) were applied in the geometric model and
as can be seen in Fig. 1, only significant AP's were selected
after correlaton analysis of all unknown variables and after
Significance testing of AP's.
introduce to AP's
STEP 1
self-calibration bundle
adjustment by all AP's
3
STEP 2
compute 1)trace for cofactor matrix
of object by elimination of AP's
2) differences between standard
deviation and coordinates
|
STEP 3
search for data information to AP's
(standard deviation, effection of
each image points,correlations bet-
ween AP's and unknown parameters,
Search for standard deviation of
iteration|| objects to existence of AP's
i
STEP 4
compare with boundary value and
result of STEP 2
!
STEP 5
detect on unnecessary AP's based
on digital informations obtained
STEP 2 and 3
pe
eliminate unnecessary
AP's
adjusted resulting
values
Fig. 1 determinability test of AP's
2.2 Detection and Elimination of Gross Errors
The conventional data snooping method is inefficient in cases
where more than one gross error exist, for many iterations are
needed for such cases. In this study the progressive data
snooping method was applied which detects and eliminates gross
errors in a continuous way. The results are updated as shown
and during adjustment of gross errors, only observations with
errors will be used together with the formerly adjusted value.
The progressive data snooping method used in this study is as
in Fig. 2.
373
(‘ota observation values y)
i
least square adjustment
Do,I-1, N
calculate calibration
Statistics amount and
non-detected gross
errors
!
detection of mesurement
values that its studented
residuals are greater than
reject values
i
calculate on MEAN, MAX correlation
coefficients for cofactors of residual
to detected observation values
i
detect max studentized
iteration residual and analysis on
internal correlation
i
max internal correlation coefficient < 0.8
!
elimination on gross errors
i
updating of a posteriori variance
;
continuous adjustment with (n-1)observations
elimination of all
gross errors
Fig. 2 flow of progressive data snooping method
3. ANALYSIS OF OBSERVATIONS
3.1 Characteristics of Satellite Imagery and Formation of
Input Data
The satellite imageries used in this study are images of the
same area aquired from different orbits and preprocessed in
level 1B and level 1AP (photogrammetric films) and 1A (digital
format in CCT). All satellite data are in panchromatic mode
and the left image is vertical (L5937') and the right image is
oblique (R26910'). Stereo model is formed as in Fig. 3.
The base to height ratio is about 0.57 and the time
difference between the left image (87.11.29) and the right
image (87.11.30) is about a day, which means small difference
of sun view angle which gives favorable observation
conditions.