SYMPOSIUM PHOTO INTERPRETATION, DELFT 1962
SPEC IFIC ATIONS FOR MI RROR -ST E R KOSCOP ES
Classification
of
Properties
The Measurements
Methods & Means
Definitions
Symbols & Units
Tolerances
Accuracies
Properties
I-Formation
I-Recording
I-Quality
Operational
Mechanical
Economic
Facts
about
Graphs
Measurements
Hurault
Jacobs
Naumann
König &
Köhler
Simon
and others
Drawings
Graphs
Use the Spec's
intelligently
Use of a stereoscope
in different fields
Aspects of Different
Stereoscopes used
for the same task
Performance
Stereoscope No.
General
Conclusions
Specifications
Good
Tolerable
Poor
j authorized by Manufacturer
Fig. 1
Properties
A useful classification into groups of the various properties is:
Image Formation: Tracing back the rays of light from the retina to the object,
the principles and properties involved in the forming of the image will be
found. This is done firstly for monocular vision, after which stereoscopic vision
is discussed and finally “scanning”.
Image Recording: The actual recording by the brain is not discussed, but
the eye needs a certain energy to function properly, so all influences on the
brightness of the retinal image will be considered.
Image Quality: The influence of the stereoscope on the contrast of small
detail in the transfer from print to eye will be expressed in a Modulation
Transfer Function (M.T.F. or T.F.).
Operational aspects: The operator should not feel that he is looking through
an instrument. A knob or adjustment possibility should have one function
only and not influence other settings.
Mechanical aspects: Requirements as to stability, transportability, protec
tion of mechanical and optical parts against rough handling are discussed.
Economic aspects: We mention price, time of delivery, service, etc.
On the complete specification sheets (pp. 48 and 49) each group contains
5 to 9 subdivisions.
The simplest methods are used to measure almost every property just
accurately enough. After all, this is not a production control, where tolerances
have to be adhered to closely, but a search for significant statistics for stereo
scopes. We established the procedure and routine on the stereoscopes in use
at the I.T.C.; in future we will test new instruments along the same lines.
