Omron V440-F, User Manual

Page: 211 / 500

8 Advanced Settings
8-28 V440-F C-Mount Code Reader User Manual
 Aperture
This determines the size of aperture to use for grading configured as a percentage of the nominal
narrow element width for the symbol under evaluation. For example, if you have a 13 mil UPC sym-
bol and you wish to grade using a 6 mil aperture you would configure the aperture to 46% 6/13 =
0.46.
 ISO 15416 Grading Serial Output
Each grade metric can be individually enabled for serial output. These outputs can be in one of three
different formats configured by the global quality output mode parameter. The mode can be config-
ured as a letter grade A-F, the actual measured metric values 0 – 100, or as a normalized grade
value score where the grade A-F is mapped from 0-100. The enabled outputs are appended to the
symbol data with the grading separator. They are appended in their order of appearance in the
grade metric section.
 ISO 15416 Grading Logic Output and Threshold 1 – 3
Each of the three logic outputs available can be configured and driven by each of the individual
grade metrics. Each output has a corresponding enable and threshold field for each metric used to
control assertion of the output when the grade drops below the threshold value.
 Overall Grade
The
Overall Grade
is calculated in accordance with the ISO 15416 specification. The Overall Grade
is the average of the individual scan line grades applied to the symbol. The individual scan line
grades are the lowest individual parameter grade seen during the individual scan. These scan
grades are not available for output. For additional detail, see
Overall
,
Scan
, and
Individual Param-
eter Grades
earlier in this help topic.
 Edge Determination
The
Edge Determination
check is done on each scan to ensure that element widths can be prop-
erly determined. Failing Edge Determination can occur with an uneven reflectance profile or with dif-
ferent types of damage. A failed Edge Determination scan results immediately as a failed decode
scan.
 Decode
Decode
is calculated and graded for each scan and provided for the overall grade calculation in
accordance with the ISO 15416 specification. The parameter grade and value provided for output is
an average value for each measured scan over the entire symbol.
 Symbol Contrast
Symbol Contrast
measurements assume 8-bit 0 – 255 intensity in the captured image correlate
directly to 0 – 100% reflectance. Symbol Contrast is calculated and graded for each scan and pro-
vided for the overall grade calculation in accordance with the ISO 15416 specification. The parame-
ter grade and value provided for output is an average value for each measured scan over the entire
symbol.
 Minimum Reflectance
Minimum Reflectance
is a measurement that, if failing, can indicate that bars are not providing
adequate response difference from the substrate, which may cause readability issues. Envision very
light gray bars on a white background versus very dark bars on a grey background. Both symbols
are low contrast but the latter has a better Minimum Reflectance score. Small relative changes to in
the light grey bars can more easily turn into errors against a bright background than small relative
changes in a very dark bar against a gray background. Minimum Reflectance is calculated and
graded for each scan and provided for the overall grade calculation in accordance with the ISO
15416 specification. The Minimum Reflectance parameter grade and value provided for output is an
average value for each measured scan over the entire symbol.
Configuration
Grade Metrics