Barcode Verification is Obsolete

 In 101

Apologies for the hyperbolic title—I must have gotten caught up in all the election year sensationalism.

However, this is a statement of belief we in the barcode quality community increasingly hear. It is driven by several factors but the availability of very aggressive scanners is the most often cited. “It stands to reason,” say the manufacturers and a good many of their users, that because of super-aggressive scanners make barcode verification is obsolete. It may stand to reason, but it fails in actual experience.

Barcode scanning is something of a balancing act, based on the tolerances expressed in the specifications for barcode print quality—ISO15415 in the case of 2D symbologies such as Data Matrix, ISO15416 for 1D barcodes such as UPC and Code 128. There is also an ISO specification for scanners, and making them more aggressive pushes the envelope a bit. That’s great when it works but it plays a risky game.

An analogous balancing act may be aircraft manufacturing. The greatest challenge in building an airplane is weight. The lighter the better—it stands to reason (remember that?); to a point. A super-light airplane is very efficient, unless and until the air frame integrity fails and lift is overtaken by gravity.

Same thing for super-aggressive barcode scanners—sort of. Consider the humble UPC symbol. Simple as it is, some of the elements (bars or spaces) in the UPC symbol are only one-thousandth of an inch (.0010″) different from each other (at nominal size); even less different at 80% magnification. Even a non-aggressive scanner operating within its ISO performance specifications is challenged to capture these microscopic dimensional differences and correctly decode a UPC symbol—and as we all know they do it all the time, all day.UPC Excessive Gain

How does a super-aggressive scanner scan barcodes that other scanners can’t? They push the limits, and that’s great—to a point. Where a conventional, non-aggressive scanner would fail to decode a symbol, a super-aggressive scanner will continue to decode it. But there could be a trade-off, and a very serious one. The ”beep” that signals a successful decode doesn’t necessarily mean the decode was accurate. Success does not equate to accurate. Put another way, a super aggressive scanner is more likely to transpose or substitute an incorrect character in a barcode than a non-aggressive scanner. Yes, this too stands to reason.

Why is this a problem? Consider the other possibility. A poor quality barcode doesn’t decode at all. This is also a serious situation—but not nearly as bad as when the barcode apparently decodes but captures the wrong data. It is certainly possible a problem will be detected in the point-of-sale transaction or the supply chain or the hospital bedside or wherever else the bad barcode is encountered, but without knowing specifically that the problem is the barcode, how much time will be lost trying to figure out what happened.

When the barcode simply fails to scan, the problem is right there in front of you—and that’s better. And that’s why barcode verification is more important than ever—even with and to some extend because of super aggressive scanners.

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