BE a AN EL A AA SSP SIN LT RATE. GÉRÉE ORPI 06 le SVG dh fo NEE Te EEE NEE er ME ES 
AERIAL CAMERA VIBRATION 
  
1972 
1977) 
ent 
P.D. Carman 
National Research Council of Canada 
d Ottawa, Canada KIA OR6 
ABSTRACT 
78) Angular vibration of aerial survey cameras is a major direct or 
indirect cause of limited image sharpness. The effect is direct if a 
shutter speed is chosen at which image motion due to vibration is 
tion significant during the exposure. It is indirect if, to avoid blurring 
due to image motion, a high shutter speed is chosen which necessitates 
; the use of a large lens aperture and/or a high speed film, either or 
- both of which reduce system resolution. 
Measurements of vibration of modern aerial survey cameras in a 
variety of aircraft over the last few years have shown maximum angular 
, velocities in the range 10 to 50 mr/s (2 to 10 mm/s image velocity at 
the film). To limit image motion due to vibration to 15 ym requires a 
shutter speed not slower than 1/130 to 1/660 s. Two comparisons are 
informative. 1) Image velocity due to forward motion in high altitude 
y 3 photography is typically 1.2 to 2.2 mm/s. 2) Measurements made thirty 
(i 3 years ago on reconnaissance camera mounts showed an image velocity of 
25 mr/s maximum for a standard mount, and 2.5 mr/s for an experimental 
mount. 
If survey mounts could be developed to consistently reduce maximum 
angular vibration velocities to 5 mr/s or less, vibration would cease 
to be a practical limitation in present conditions and system resolu- 
tions could improve by 35 to 55%. 
  
1. INTRODUCTION 
The adverse effects of image motion on photographic image sharp- 
ness must have been known for as long as there has been photography. 
Long before the First World War the British Admiralty had a problem 
with stable orientation of motion picture cameras in aerial balloons.! 
1 NRC 16656