Calibrated Conformance Standard Test Cards: What are they and why are they needed?
When it comes to verifying print quality, bar code printers rely on commercially-available verification equipment. Yet differences often crop up between the results of one verifier versus another.
Up until recently commercial verifiers designed specifically for bar code print quality analysis helped grade and judge a bar code’s print quality, however, there was no standard way of verifying a verifier's results. While print quality standards existed, what was needed was an instrument sensitive enough to provide highly accurate measurements and a NIST-traceable (National Institute of Standards and Technology) physical standard for use by verifier manufacturers and end users.
In 1985, Dr. David Allais of Intermec challenged Sprague Ackley to develop a device to accurately measure bar code symbols. After two years of work, they developed what became known as "The Judge" -- an automated scanning device that could capture thousands of discrete reflectance readings across a single bar symbol.
The Judge provided an extremely accurate, repeatable method of verifying symbols -- but it was not feasible to commercialize it as a verifier.
What was created was a set of Calibrated Conformance Standard Test Cards (CCSTCs) with specifically engineered flaws that could be used to check a verifier's results against the standard's known parameters. To create the cards, each sheet containing the flawed symbols are put before the Judge and verified. The Judge’s reported results are then registered on to each card and a unique, verifier checking tool is thus created.
GS1 US (then the Uniform Code Council) developed the set of CCSTCs for linear symbologies. While the test cards are designed specifically for GS1 symbologies, they are equally valuable in calibrating and testing verifiers for any other linear symbology.
With the adoption of Data Matrix by GS1, there had been calls for a related set of CCSTCs for matrix symbols. Although the linear test cards can be used to check many of the print quality parameters of matrix symbols, error correction and other features inherent in Data Matrix cannot be checked with the linear cards.
In response to this demand,
GS1 US developed the 2D Judge program which required the development of both the
2D symbol test cards as well as the verifier to test these cards. This project
leveraged the cooperation and expertise of AIM's
Technical Symbology Committee (TSC),
The 2D Judge hardware was
developed under contract at
A contract to operate the 2D
Judge and produce the CCSTCs was awarded to PIPS,
Inc and the system was transferred from
Test card sets, for both linear and 2D symbols, can be purchased through PIPS, along with expert assistance and consultation on the specifications and use of the cards.
CCSTCs do have a shelf life. Even though they are produced with the utmost care and with the highest quality materials available, materials do degrade over time and CCSTCs are to be replaced every 2 years.
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