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TRENDS IN DESIGN OF DIGITAL EQUIPMENT
FOR PHOTOGRAMMETRIC INSTRUMENTS
By
U. V. Helava
Bendix Research Laboratories
Southfield, Michigan 48076
U.S.A.
ABSTRACT
Digital equipment has been incorporated in some photogrammetric
instruments for many years; much more of it will be seen in future in
struments. The reasons are primarily economical. The designers of
photogrammetric instruments must be able to make full use of rapidly
advancing digital technology to transfer to the instrument user full
benefits of the progress paid for by other parts of economy. This paper
reviews the use of digital equipment in photogrammetry as well as the
trends in general digital design and explores where such trends may lead
in photogrammetry. The conclusion is that the designers of photogram
metric instruments are confronted by significant challenges in meeting
their future responsibilities.
The continued advances in photogrammetry are primarily due to the
development of more accurate and efficient instruments. Today, as never
before, we have an unparallel opportunity to use and exploit new tech
nology that will yield more cost-effective instruments. The future of
our profession and its role in the world economy depend largely on how *
we pespond to this opportunity.
SCOPE OF DIGITAL FUNCTIONS IN PHOTOGRAMMETRIC INSTRUMENTS
With the notable exceptions of mechanical structures to carry the
photographic film or plate, and of optical viewing, nearly all functions
needed in a photogrammetric evaluation instrument can be replaced by
electronic or electromechanical means. While such replacement may not
be practical at present, we must keep in mind that it is feasible, and
thst it may even extend to mechanical structures as digitizing at the
data acquisition level, a la ERTS, becomes better developed. Funda
mentally then, the scope of digital functions in photogrammetric instru
ments can be seen to be extremely wide.
The entire scope may not be realized in the near future, if ever.
On the other hand many digital functions are already in widespread use
in photogrammetry. Consider the use of encoders, for example. These
devices perform among other things, a function equivalent to measuring
the magnitude of mechanical translation or rotation. In fact, encoders
