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Barcode ISO Verification

During the 1980s, two factors led to attempts to improve the traditional verification technique. One was the disparity between traditional verification results and the real life performance of symbols, and the other was the increasing number of product rejections by customers based on differing verification results between the supplier’s instrument and his customer’s.

A wide-ranging programme by a group of experts from bar code and user industries working on all types of scanning systems determined the factors that most directly affect symbol-scanning performance and resulted in the analysis of the Scan Reflectance Profile (SRP). This methodology was originally known as ANSI verification because it was first described in theUnited States’ standard ANSI X3.182, published in 1990 under the title Bar Code Print Quality Guidelines. The method was then defined in a European standard (EN 1635), published in 1995, and an international standard (ISO/IEC 15416), published in 2000. ISO/IEC 15416 is the definitive international specification of the ISO bar code verification methodology, and the numeric grading system is used.

The method, as described in the ISO/IEC 15416 standard, is technically fully compatible with the ANSI X3.182 and EN 1635 method, so verifiers based on these standards are not obsolete.

GS1 General Specifications Bar Code Production and Quality Assessment In simple terms, an ISO verifier looks at the symbol in exactly the same way a scanner sees it. The ISO verifier reports its assessment of the symbol quality not as a single “Pass” or “Fail” decision, but as one of a range of four passing grades (from 4 to 1, in order of decreasing quality) or one failing grade (0). This enables an application to set the most appropriate minimum grade for acceptability. It may be noted that the ANSI standard uses the alphabetic scale A to D for passing grades and F for failing symbols, but the grade thresholds are identical.

The relationship between symbol grades measured in this way and the way the symbols behaved when they were scanned was so close that users  rapidly came to accept the SRP assessment method for verifying symbols received from their trading partners.  Users knew that as long as a symbol achieved grade 1.5 or better it would give them acceptable performance when they had to scan it to capture the encoded data.

Note: The GS1 System requires that the Quiet Zone be a measured parameter for EAN/UPC Symbology, GS1-128 Symbols, and ITF-14 Symbols per the values expressed in  ISO/IEC 15416,Section 5.