REA MLV-2D Operating Manual page 27

5. When determining the measuring area manually, the parallel alignment or the
90° angle must be observed. When the bar codes are positioned diagonally in
the field of view of the camera (when they are otherwise too wide), the
measuring area must be determined at an angle of 90° with respect to the bars
and not in parallel to the edges of the field of view.
Figure: Manual ROI with code at an angle
6. Measurements should not be taken in direct sunlight, under direct light
irradiation (e.g. spotlights) or near to infrared sources (heat emitters). Such
ambient light sources will change measurement results and sunlight will
produce unusable results.
7. The sample to verify must lie flat and level on the measurement surface. If this
is not the case, the image captured for measurement will be distorted and
falsify the measurement results. The risk is particularly high for foils and labels
that are processed as goods on rolls. From the perspective of the device, the
camera must always be able to image the code vertically and lighting must be
at a 45° angle (only DPM measurements have special requirements).
8. Transparent materials must always be measured on a flat, uniform and opaque
black background (typically with a maximum reflectance of 5%). If different
measurement backgrounds are used, measurement results will also be different
and not comparable.
9. The synthetic measurement aperture should always be at about 80% of the
module width in order to obtain good decoding results. For ISO/IEC 15415 or
DPM (ISO/IEC TR 29158) 2D code measurements, the measurement aperture is
determined automatically by default.
10.When there are several codes in the field of view and a code, which is not the
one centred in the middle, is recorded, the codes that are not required must be
covered.
11.The REA MLV-2D must be adjusted regularly and its measurement accuracy
verified (calibrated) with the aid of test equipment monitoring (see sections 11
and 12).
12. Automatic identification and decoding may recognise codes incorrectly or fail to
recognise them entirely. In such cases, the operator must assess whether or
not the result is valid and, if necessary, should repeat the measurements with
corrected settings or perform them several times.
© REA Elektronik GmbH, 64367 Mühltal, Germany --- REA MLV-2D Manual Version 3 – 21/12/2015
REA VERIFIER
Page 27 of 98