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gio dein verd id cio TEL GE ios 6 A CA OC SEL IN EE PURE IN CS MO od ARE e So o de TORO ut t E OE I4 D LK See Me PTE a A BE tb AON DE Ts EEE ER DE AR)
Summary: The studies reviewed by the WG-3 members, their research, and the
answers to the questionnaire show that some photogrammetrists are aware
that the flight environment can cause degradation of image quality and changes
in geometry from that reported in the camera calibration certificate. Be-
cause present methods of survey deal with rapidly varying environments, and
because responses of camera materials to environments of temperature and
pressure are not immediate nor exactly predictable until equilibrium is
attained, it is impossible to state the changing values as a function of
real time. In other words, since the camera is experience gradients during
the survey, each exposure may be slightly different in image quality and
geometry from adjacent exposures and the first significantly different from
the last.
As a result of information available from Meier's studies and knowledge of
the flight conditions as established by Worton and the WG-3 questionnaire,
a project will be established at Hill Air Force Base to calibrate a camera
under simulated flight conditions (other than angular motions), to determine
geometric changes. Similar tests will be conducted to test resolution re-
sponse.
The design of the experiment is presently in the discussion stage and de-
tails need to be worked out such that the environment simulates the average,
extreme survey condition of temperature and pressure. The results of the
study will be reported at the Congress in 1980.
A different situation exists for degradation due to angular motions of the
camera during exposure - to vibration, pitch, roll, and yaw. Studies
presented by Carman and Worton show the magnitude of possible degradation
of image quality and point out the gains possible with improved control.
Reducing exposure time is one method that lies within the domain of every
aerial surveyor/photographer to investigate. The "tradeoffs" with exposure
time are film speed via film processing, or faster emulsions.
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