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Rf = film resolution in lines /mm Hf = height of standard motion
picture projector aperture in
millimeters.
For 35-mm film H/ Rt
15.25 mm 30.5 Rf
For 16-mm film H/ = 7.21 mm Rt = 14.42 Rf
B. Conversion of Television Scanning Lines per Frame to Lines of Vertical Resolution (Television).
Rtv = b(aL)
where Rtv = vertical resolution (televi
sion) in lines
a = vertical blanking factor b = line scanning factor L = total number of scanning
lines per television frame.
Substituting present standards:
a = 0.92 min., 0.95 max., 0.935
average
6 = 0.75 (representative) L = 525 lines
Rtv = 0.701 L = 0.701 X 525 = 368 lines.
C. Conversion of Maximum Video Pass Frequency to Lines of Horizontal Resolution (Television).
Rtk = 2/maxn/A
= horizontal resolution (televi
sion) in lines = maximum video pass fre
quency in megacycles — active time (unblanked) of
horizontal sweep in micro
seconds
where Rth
/max
where C = horizontal blanking factor
Fr = frames per second (television)
A = television aspect ratio.
Substituting present standards:
/max = 4.5 megacycles
C = 0.82 min., 0.84 max., 0.83
average Fr = 30 frames/sec
then Rth = 2 X % X 52.7 X 4.5 = 79 X 4.5 = 356 lines
or general formula
Rth = 79 /max
D. General Conversion Formulas for Equal Resolving Power Between Film and Television.
1. Television scanning lines per frame in terms of film resolution (required for equal vertical resolution) :
L = (2/ab)Hf X Rf
2 = 0.935 X 0.75^' X Rf
L = 43.5 Rf for 35-mm film L = 20.6 Rf for 16-mm film.
2. Maximun video frequency in terms of film resolution (required for equal horizontal resolution) in 525-line, 30frame television system:
/max = (jj X L X Fr X Hf X IQ~*\ Rf
3^3 X 525 X 3° X 10~6 X
fmax = 0.386 Rf megacycles for 35-mm
film
= 0.182 Rf megacycles for 16-mm film.
3. Maximum video frequency in terms of film resolution (required for equal horizontal resolution in a 30frame television picture), if the number of scanning lines in that picture has been chosen to give equal vertical resolution:
A = 4/3.
/max = 0.032 Rf* megacycles for 35-mm
film
= 0.00715 Rf2 megacycles for 16-mm film.
The above equations have been applied to several values of film resolution for both 35-mm and 16-mm sound film and the results have been tabulated in Tables I and II. These tables list
H. J. Schlafly: Television and Film Resolution
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