Omron MicroHAWK V320-F User Manual page 157

8 Advanced Settings
This averaging provides a generalization of the information in the image consistent with typical reading
equipment acquisition techniques. Verification systems implement the aperture based on the physical
dimension of the symbol under test and the application standard guidelines such as GS1. In a reader
with varying optical setup and no calibration process there is no means to know the size of the symbol
under inspection. Because of this the aperture is a configurable parameter as a percentage of the
narrow element of the symbol under evaluation. The default value provides a general use case similar
to application standards, but it is the users responsibility to ensure this percentage matches the grading
objectives. A representation of the effects of the aperture is shown below. Selecting a larger aperture
creates more of an averaging effect that is less sensitive to defects but may lower modulation.
Aperture Effects
 Overall, Scan, and Individual Parameter Grades
The overall grade is calculated in accordance with the process defined in ISO 15416. This is often
misunderstood so a review is provided here. The overall grade is an average of the individual scan
grades that are applied over the inspection region. The individual scan grades are not provided but
these are calculated internally as the lowest of grade of any single parameter grade evaluated in that
scan or zero if the scan fails the edge determination or quiet zone requirements. The individual
parameter grades provided are averages of only those parameters grades where they are evaluated.
These individual average parameter grades available are not themselves part of the overall grade
calculation but can be helpful information for diagnosing degrading overall grades. This creates some
circumstances where the overall grade can be lower than the lowest average grade particularly when
there are degrading features in the symbol from different parameters.
Configuration
 15416 Grading Serial Output
Enable or disable the output the grading value. The output is either in value 1 to 100, or in letter grade
A to F.
 Aperture
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 symbol and you wish to grade
using a 6 mil aperture you would configure the aperture to 46% (6/13 = 0.46).
 Overall
Disabled
The overall grade is not formatted as part of the symbol output.
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MicroHAWK V320-F / V330-F / V420-F / V430-F Barcode Reader User Manual