Yuri Knizhnikov 
  
Rs 1/ 230p 2? (1) 
Or 
Rz 2p) pa, Q) 
Dx 8 pia - sizes of the discrete image pixel, mm. 
Formula (1) was proposed in (Szangolies, 1987), and the second one was studied in (Knizhnikov, Zinchuk, 1998). 
These equations are correct under such conditions as: 
pr)" 2 1/ 2R" - for formula (1), 
(pj. * pia)? 2 V 2R" - for formula (2), 
R" - resolving power of the initial image, mm !. 
A/D conversion is also connected with the decrease of the photographic contrasts. This transformation is determined 
from parameters of the office photogrammetric scanners (» and d). Its combined influence may be estimated with 
modulation transfer function (MTF): 
n 
T(R)= 11 Ti(R), (3) 
i=l 
T(R) - modulation transfer function from the i-scanner's parameter. 
MTF from scanning aperture (b) was proposed in (Frieser, 1975): 
Ti( R) 2 sin(tRb)/ TRb, (4) 
R - resolving power of the initial image. 
The effect of the scanning aperture size is shown in figure 1. 
e £5 
ADP (x) | rdi > 
| 
bh 
—D A by 
Figure 1. Modulation of an initial photographic contrasts under different size scanning apertures (5; and 55): 
AD" (x) - photographic contrast of initial space image; AD"' (x) - photographic contrast of produced space image 
We have proposed that MTF from sampling rate (d) is an analog of the MTF from scanning aperture, so: 
T,(R) = sin(aRd)/ Rd, (5) 
R - resolving power of the initial image. 
So, the combined influence from b-d parameters may be estimated with equation: 
T(R)=T(R) T,(R)= sin(TRb)/ nRb sin(nRd)/ nd. (6) 
  
502 International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B3. Amsterdam 2000.