An apparatus for the photoelectric measurement of an essentially planar
measurement original includes a photoelectric scanner and a positioning
arrangement for the two dimensional movement of the scanner over the
measurement original positioned on a supporting surface and the
positioning at defined measurement locations on the measurement original.
The positioning arrangement is constructed as a type of SCARA robot and
includes a stationary base, a first and a second movable robot arm and a
positioning control. The first robot arm is mounted on the stationary
base for rotation by a motor about a first axis of rotation perpendicular
to the supporting surface. The second robot arm is mounted at the free
end of the first robot arm for rotation by a motor about a second axis of
rotation perpendicular to the supporting surface and carries the scanner,
and the positioning control is constructed for rotation of the two robot
arms according to externally supplied positioning commands. The apparatus
requires relatively little mounting space, is suitable for both remission
and transmission measurements, and can be realized at relatively low
construction cost.