A barcode is a machine-readable pattern applied to products, packages, or parts. 1D and 2D codes contain data used for informational and marketing purposes as well as for tracking products throughout their lifecycle. Codes are applied to parts one of two ways: by applying the code to a package or label, usually using inkjet or thermal printing methods, or by permanently marking the code directly on a part via a direct part mark (DPM) method such as dot peen, chemical etching, or laser marking.
Using 1D or 2D codes reduces overhead costs by automating and simplifying supply chain management, inventory, and purchasing. Using barcodes also improves safety and liability. For example, governments around the world have started to require medical devices and pharmaceutical manufacturers to apply machine-readable codes on every package down to individual medicine containers. Should a defective product reach a store shelf, automated tracking of every package will accelerate safety recalls while making quality control data available to the entire supply chain. Also, an increasing number of industries must comply to the International Organization for Standardization (ISO) code quality guidelines or have their own barcode quality parameters that need to be met and checked to ensure that codes can be read throughout the supply chain and won’t result in slowed production or retailer fines for poorly printed or unreadable codes.
Barcode readers scan barcodes and translate them into alphanumeric digits. This information, that typically includes a description of the item, number of items in stock, and price, is sent to and stored in a database. Some barcode readers use lasers to decode the information while others use lights or cameras to capture the barcode image to then read and decode it. Depending on their software, the reader may provide print quality metrics useful for process control and improvement. But no two barcode readers are the same—they can differ in image resolution, optics, lighting, and decoding algorithms. In fact, many barcode readers include advanced decoding algorithms designed specifically to read deformed, challenging, and hard-to-read codes. This means that one barcode reader might successfully scan a code, while another later on in the supply chain does not.
Neither quality control testing nor a reader’s process control metrics can reliably gauge how two different barcode readers will handle the same code. Overall, scanning a barcode with a barcode reader simply tells you that it can be scanned by that particular reader and does not guarantee quality.
While barcode readers are used to read codes, barcode verifiers are used to grade the quality of codes. When 1D and 2D codes are printed or marked, minor issues can start to affect the readability of the code. Using a barcode reader to test the quality of a barcode will only tell you if the code can be read by that particular scanner. Barcode verifiers, by contrast, ensure codes meet an industry’s—rather than an individual producer’s—quality threshold. Barcode verifiers are a superior measure of symbol readability because they normalize the range of performance among various types of readers, from laser scanners to image-based readers.
The verification process is very different from simply reading a code:
- The verifier must be calibrated. Conformance calibration cards contain symbols with intentional imperfections that are used to check the reporting capabilities of the verifier and document conformance to industry standards such as ISO/IEC 15415 and GS1 specifications.
- Industry standards dictate the type of lighting arrangements that are permitted, usually a variation of 30-, 45-, 90-degree, and dome lighting.
- Verifiers take more time to analyze a code and generate more data than a reader. They measure different quality parameters such as symbol contrast, modulation, defects, and decodability, and produce a final grade (usually A through F). Reports can be printed or exported to prove compliance to quality standards.