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International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B2. Istanbul 2004
24 DI
J Í | | —m— Pan 200 |
2:2 : | 7-7 Pan 400
E Pan 80
201 ; i : uh 1 —#— Foma 200 etre
] | Kodak 3404
18 4 | | 74 Kodak 3412
m |] Kodak SO50
| —e—Typ 38
45 4 C] | Ty 42 f pm
id 7 | | —#—Typ 42L i
= f | —— —
of 1 | |
124 r |
1.0 - des d
J | |
0.8 - T uu — — ———X— —
1 | proces: Kodak 885
0.64 = "em or
] | temp: 30 C
0.4 T i T i T T T 1 T i T T
0 100 200 300 400 500 600 700
S
Fig. 6. Graph of relation gs =f(S;so4) for films processing in
solution 885 at T=30°C in Versamat processor.
4. APPROXIMATION OF THE CHARACTERISTIC
CURVE BY MEANS OF A POLYNOMIAL
The quality of the obtained characteristic curve is crucial for
sensitometric study. It is frequent that the characteristic curve
graph is of even stepwise shape or uneven. For the purpose of
the study, the characteristic curves were smoothed by means of
a polynomial approximation. The degree of the polynomial was
appropriately selected to approximate the characteristic curve. It
was proved that the best approximation of the curve shape for a
21-step tablet was achieved by a polynomial of 9th degree and
further increasing of the degree has no impact on the quality of
the results.
Examples of the calculation results are presented in Fig. 7.
225 -[——1—
pp pee rer qe
| | | |Typ “2
Ï | | |
220 -] | | | Lu a
| | | |
215 - | | | -
| [or]
| | | | | 4
| | | |
x 210 --—- |t us + =
0) | | | |
205 4 —— | Be 2
| |
NS | 7
i 9-1 |
200 Soi ee e a notes -]
EA Da
4 | | | | {
| | | | | |
195 rl free ETES EY
2 4 6 8 10 12 14 16 18 20
P:
Polynomial order
911 TTT
1 | | | Agfa Pan 200 § 1
230 +-———— i —— e - erred rrr rea
| | | | |
| | | | |
| | | |
| | | | 7
VI | H | 1 «1
| | | | |
= | | | | | |
qo um d et | el
| | | | |
| | ! |
2104 EC 3 HE len
] | | | | |
| | | | |
205 + i | | | | 5
> ee | |
T77$—9-.6$-——e—6—e-——6—9—9—9 |
ftp tt re a ed ra tre
2 4 6 8 10 12 14 16 18 20
Polynomial order
81
T T T T T Y T T T T T T Y T
1 | 9—9— e—e6 e—e—* |
As ae
1.26 À | | zl
1.24 4 t0 ——————
i | | |
|
zat | pol d rete]
Oo | | | ]
1.20 TAL ez]
| | | J
1718-1 dde cts dur fred
| | +
146. — dr tone rm jen ed
] | | Typ 42 1
| | | |
1.14 v RETE DI
2 8 10 12 14 16 18 20
Polynomial order
1.42
c T , T
| | |
1.40 ] Reden 3
1384 | Lem | | =
1 | Í | 4
1.36 | | | ]
J i | | 4
1.34 - E j =
4 | | | | | -
JAR eer eed
© + | | | 4
1.30 — | | | i 4
028 | rus MIS À
1.26 4 | = d +
1.24 À | par pd ecd |
J | | Agfa Pan 200 I
| |
1.22 : a, FER
2 8 10 12 14 16 18 20
Polynomial order
Fig. 7. Dependence of arithmetic photosensitivity (S,,) and
mean gradient (gg) values on the degree of the polynomial for
the Ukrainian material Typ 42 and Agfa PAN-200.
The developed sensitometric program uses the above described
curve and enables automatic determination of the basic
sensitometric quantities according to ISO A and GOST. The
quantities obtained by means of other determination methods
were very close.
S. EXPOSURE DETERMINATION FOR ACHIEVING
MAXIMUM RESOLVING POWER
From the point of view of photographic information acquisition
during the OS missions, it is important to determine the
exposure for which the maximum resolving power is achieved.
Optimum exposure conditions for which the maximum
resolving power is achieved may be determined in a traditional
way by means of a series of exposing test stripes of various
contrast. For a test of a given contrast, the dependence of the
resolving power on the luminance is determined graphically.
The maxima of the relations indicate the optimum level of the
film exposure for which the information capacity is the greatest.
This method is extremely laborious and time consuming.
Additionally, the precision of subjective assessment of the
resolving power in the specific fields of the sample plays an
important role here. Therefore, to obtain reliable results, it is
required that a few appropriately trained and experienced
persons are involved. The changes of the resolving power R=f
(log H) are similar to the changes of gsr =f(logH) in the
obtained results while maxima of the values occur for the same
exposure..