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Title
Proceedings of the Symposium on Progress in Data Processing and Analysis

DISTINGUISHABLE DETAILS IN AIR PHOTOS
Werner Schubert
Fils AS No!fen
F'uschkinplatz 1
The content of inforsat ion of air photos suet be very high to obtain a possibility of multiple interpretation.
One of the most important desands is to distinguish Details on a very high level. In general the property
""esrodort i r.
ГМ c rî-U
u* is composed of several single parameters,
t ransrer
transfer f
■ f •; r r?t
Decisive paraоe ters: шоD ui
; ■& а f> C d ; ; i t O G
global parameter
^production of details" depends on
•ne »ait: parameter limiting frequency
f objective and film. Another important parameter is
siting frequency, focal length and altitude.
' : OX- с Г:
1 ink'ПС
moduiation
c ru e spcLidi frequency given о y the
knowledge about the con
-....a ,nn^-. ; 4 -л
ditiens of exposure
1owe to determine t-
■r. _■ v, ■ 'itii :•
7 ili d
details is
camera
• 7'F -1
n ■ v u H D 6 ; ri e о r
Details,
hts one nac
:onsiDer a
rue spatial freouency
- L _ i . -
c,. 4 t
ces.
a question
¡cos but also a question of reaching results. We Here ;■
Л.г.Ь.г
want to get 'a lot of Information f'oi
for different fields, e.g, phi
interpretation of ecological problems.
V. ¡7 7,Q £ 4 * 7. “ 4- 7 7 — .*i -, 4 3 -, r 4 7. _."J ’■ — 4 - r. —,-, ^ К A p b 7 - ; —
Li earl у distinguishable details are necessary for ail
kinds of interpretation as for mapping as for agri
culture, geology or hydrology. Therefore we must kno#
which factors of influence are objective for gcoD c>
oao distinguishing of details.
Basis for the foi lowing Descnptio
ipliOn i!
i m a n eye.
isyecidii•
if l. d ji d J-1 1 i L ‘У
•x ч T ч-г ч : : ■»: ч
г. - Г 1 •- r. p •. •. ¡0 K n -, r, i •. n *• "h . 1 rt *. r + t Г/ rv. v n Г f*. *. n r-.
i-i a î> i. 1 > > Lj U i r** / i • / wj u* 1 •.iil.t'j t f j Ui Lj U i f; i a f > ÿ w
Г Г: •: ПИТ ï
and reproduction of detail
Had t Г: rnr«t;iHpr
15. in a practical way we
chose parameters which influence the
transfer of information of the system; target - human
eye;
1 true spatial frequency of the target according to
its real geometrical structures and its spectral
absorption in relation to the surround
2 modulation transfer of the used lens depending on
the spatial frequency
3 modulation transfer of the used film depending on
the spatial frequency
4 effective Un film reproduced/ spatial frequency
5 conditions for viewing the film depending on the
frequency character of the human eye
Now we should answer the question how is the inter
action between the described parameters.
224
possible to approximate rather simple
geometric shapes, we can say that real targets have
iKt teCtauuie
buuj Si «pit yase ы." yclui •
as a special shape o? rectangle, In this case we get
the true spatial frequency
i. : Li t' t-ii ¿Li cl j 7 • f* LL t'.- i L Ï :
:-pt
target m mm) A special kind are targets with frame-
shaped structure, m mis case
the frame, For ellipse and circle the above equation
is changed to
R"=!/d
Id - diameter of circle or shorter axis of ellipse)
Circles with frame-shaped structure have a true spa
tial frequency calculated after eq.l.
2. nodulation transfer of lens
To characterize an objective it is not possible to
take only one modulation transfer function, Therefore
we make a compromise and use the modulation transfer
function which describes a beam in a distance of 33mm