REA
VERIFIER
© REA Elektronik GmbH, 64367 Mühltal, Germany --- REA MLV-2D Manual Version 3 – 21/12/2015
Page 50 of 98
7.14
DPM measurements
Supplementing evaluation to the ISO/IEC 15415 standard, the verifier can also
provide evaluations for DPM (Direct Part Marking) codes as specified in Technical
Report ISO/IEC TR 29158. ISO/IEC TR 29158 is in large part an adoption of the AIM
DPM Guideline published back in 2006, which deals with the quality grading of direct
part-marked matrix codes.
ISO/IEC TR 29158 (DPM Grading) both extends and partially amends ISO/IEC 15415,
and utilises an identical grading system. An important aspect of this quality
assessment is that a quality grade of "Good/3" according to ISO/IEC 15415 must be
interpreted very differently than the same grade of "Good/3" evaluated according to
ISO/IEC TR 29158. Typically DPM codes are more difficult to read. In addition, the
lighting requirements and decode algorithm specified for code scanners must be
specifically designed for reading DPM codes.
In evaluation reports, one noticeable difference is that "cell contrast" and "cell
modulation" are specified as parameters within the DPM verification process. Both
parameters are relative criteria.
The DPM grade makes adjustments for the lighting and the measurement aperture
(synthetic aperture). The entire grading process therefore differs considerably from
the ISO/IEC 15415 base method, which uses fixed and adjusted settings checked by
means of calibration.
Measurements in DPM mode take much longer to complete
, since multiple
measurements must be captured in sequence until the contrast specified by the
standard has been achieved (the light exposure is changed until this target is met).
8
Displaying the evaluation
8.1
Verification reports
Depending on the preset values in the options, the level of detail of the verification
reports displayed can be adjusted and changed to suit individual requirements. The
various presentation formats are selected by using the icons
The left-hand icon presents a detailed graphical verification report on the PC monitor.
This view is designed for qualified personnel with corresponding background
knowledge and shows all of the verification results obtained in detail, partially in the
form of clickable sub-windows.
The second icon shows the evaluation as it would appear on a printout (long printout).
Compared to the graphical view, some details can be seen better here listed one after
the other.
The third icon shows a short report. This view provides a compact summary of all
verification results, which can be used by trained routine personnel.
