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Grading Changes for ISO 15416:2016 1D Barcode Verification


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Impact of ISO 15416:2016 Changes to Barcode Grading
Summary:
The changes to ISO 15416:2016 (released December 2016) result in a transition away from the historic letter method of assigning a quality grade.  The method of calculating decimal grades for several symbol parameters has also changed, resulting in some cases a higher calculated grade for a given symbol compared with the previous version of ISO 15416.
  
 
  • The first published standard for barcode quality was the ANSI X3.182-1990, which built upon previously published barcode guidelines from the UCC (Uniform Code Council).  This standard defined print quality guidelines and the foundation concepts such scan reflectance profile, aperture, and lighting wavelength. ISO 15416:2000, in the informative Index E, defined Alphabetic conversions to the numeric grade using A through F letter grading.  Letter grades conversion of A through F were assigned to the different numeric parameter grades, and the overall grade, e.g. C = range of 1.5 to 2.4
  • A European Norm for barcode quality grading, EN 1635, was published in 1995, followed by ISO/IEC 15416 (1st edition) in 2000.  ISO 15416 used concepts from both the ANSI and EN standards and is now viewed as the single global standard which should be used for the grading of 1D printed barcodes (except DPM)
  • The concept of alphabetical letter grade conversion for the numeric grading has always been informative (optional) in ISO 15416
  • LVS software for many years provided both the numeric grade and the optional Letter grade.
Historical Background for Barcode Grading
 
  • The first published standard for barcode quality was the ANSI X3.182-1990, which built upon previously published barcode guidelines from the UCC (Uniform Code Council).  This standard defined print quality guidelines and the foundation concepts such scan reflectance profile, aperture, and lighting wavelength. ISO 15416:2000, in the informative Index E, defined Alphabetic conversions to the numeric grade using A through F letter grading.  Letter grades conversion of A through F were assigned to the different numeric parameter grades, and the overall grade, e.g. C = range of 1.5 to 2.4
  • A European Norm for barcode quality grading, EN 1635, was published in 1995, followed by ISO/IEC 15416 (1st edition) in 2000.  ISO 15416 used concepts from both the ANSI and EN standards and is now viewed as the single global standard which should be used for the grading of 1D printed barcodes (except DPM)
  • The concept of alphabetical letter grade conversion for the numeric grading has always been informative (optional) in ISO 15416
  • LVS software for many years provided both the numeric grade and the optional Letter grade.
 
 
Summary of Changes with ISO 15416:2016
  • Computation method for Defects has been modified
  • Addition of an interpolation method for scoring of symbol contrast, modulation, and defects.  A decimal grade (in steps of 0.1) is now associated with these parameters whereas previously an integer value was used.  The purpose of the change was to reduce meaningless grade level fluctuations when small changes in measurements cause a grade to transition between integer grade levels defined in ISO 15416:2000.  This new calculation method in some cases will result in a higher averaged score for the above parameters using this interpolation method compared with the method described in ISO 15416:2000.
  • The new calculation method also results in a change in the numeric range of what was previously associated with a given alphabetical letter grade. 
  • The use of Letter grades going forward is being de-emphasized due to the lower precision associated with a letter grade compared with a decimal numeric grade.     
 
 Impact to LVS-95xx Version 4.3 Software

 
  • “Ranges” that were previously defined in LVS-95xx software associated with a color will be changed to align with the ISO 15416:2016 calculation.  For example, blue will have a range of 2.0 – 2.9, where previously it was 1.5 – 2.4.
  • Letter grades have been removed from the grading result, based on the ISO premise that numeric grades are a better indicator of symbol quality, and the inconsistency between the new grade calculation without a comparable change of the grade ranges associated with Letter grades having been implemented in ISO 15416:2016.
GS1 several years ago removed letter grades from the GS1 General Specification Tables, and now only specifies a numeric grade in those tables. 
 
 
 
 FAQs
  1. Why are letter grades no longer being reported in version 4.3 of LVS-95xx software?   The letter grade is not used as part of the normative standards of ISO 15416, and the informative table D.1 that has a letter grade reference is not consistent with the 15416:2016 ranges of values for scan reflectance profile values shown in the standards.
  2. Will my barcode grade change when using v. 4.3 compared with earlier versions of LVS-95xx software? Some barcodes will receive higher scores due to the changes in ISO 15416:2016.
  3. What if a customer has an internal specification that requires use of a letter grade?  A customer can continue to use version 4.1.0j or refer to the ISO 15416 informative table D.1 for a cross reference of letter grade with numeric range.  Microscan recommends that customers follow the ISO 15416 normative standard that states the symbol grade shall be reported as a numeric value with decimal.
  4. Does GS1 require a numeric or an letter grade? GS1 Tables define a 1.5 as the minimum required grade for most applications.  A letter grade is not indicated in the GS1 Symbology Specification tables.
  5. How does this change impact 2D symbol grading?   ISO 15415 also defines that symbol grade shall be reported as a numeric value with decimal.  For consistency purposes version 4.3 will also no longer report a letter grade for 2D symbols.
  6. Can an existing LVS-95xx be upgraded to v. 4.3 software and use the existing calibration card? Yes. The formulas used for calculating calibration parameter values such as symbol contrast and modulation have not changed.  Only the calculation of the numeric grades associated with the parameter values have changed.
 
FAQs
 
  • “Ranges” that were previously defined in LVS-95xx software associated with a color will be changed to align with the ISO 15416:2016 calculation.  For example, blue will have a range of 2.0 – 2.9, where previously it was 1.5 – 2.4.
  • Letter grades have been removed from the grading result, based on the ISO premise that numeric grades are a better indicator of symbol quality, and the inconsistency between the new grade calculation without a comparable change of the grade ranges associated with Letter grades having been implemented in ISO 15416:2016.
  • GS1 several years ago removed letter grades from the GS1 General Specification Tables, and now only specifies a numeric grade in those tables. 

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