What's the Difference Between Barcode Quality Software and Barcode Verification?

Barcode quality software provides basic grading based on selective ISO parameters, which can vary between companies due to proprietary algorithms. While useful for internal monitoring, these tools may cause inconsistencies when codes are read by different scanners.

Barcode verifiers grade barcodes according to ISO quality standards. Verification provides trustworthy results between devices, ensuring compliance with industry requirements. However, not all setups allow ISO-compliant verifiers due to constraints like mounting or barcode placement. Gauging readability with just barcode quality software can be difficult and cause additional problems down the line. ISO 15426-1 and ISO 15426-2 requirements include:

• checking all quality parameters
• using a specific lighting set-up
• ensuring consistent calibration

These used to be the only two options for barcode quality control: ISO-compliant verification or barcode quality software. But many manufacturers wanted an alternative approach to producing consistent, well-defined, and broadly understood results like those produced by a verifier. Cognex offers a middle road approach called standards-based grading.

What is standards-based grading?

Standards-Based Grading (SBG) operates on select DataMan fixed-mount barcode readers and uses the same ISO-based algorithms and calibration processes as standard verifiers.

Standards-based grading vs barcode verification

Standardization can put limitations on the type and placement of barcodes that can be verified. SBG is a way to get the reliability of ISO-compliant verification without the limitations.

When comparing SBG and barcode verification, the primary distinction lies in flexibility vs standardization. Verifiers excel in scenarios where ISO compliance is non-negotiable since they provide universally accepted results. Meanwhile, SBG prioritizes adaptability for environments with physical or budget limitations.

Another significant difference is lighting. With verifiers, strict ISO-defined lighting angles ensure universal scan compatibility. SBG, on the other hand, allows for custom lighting solutions while maintaining grading accuracy through calibration.

SBG provides significant quality control advantages:

• Uses the same algorithms and calibration methods as verifiers.
• Reports all ISO quality parameters, ensuring comprehensive evaluations.
• Supports custom configurations to meet unique application demands.

SBG uses the same verification algorithms and user interface as our verifier line, with lighting as the main difference. ISO 15426-1 and 15426-2 set strict lighting and angle requirements, but by removing the lighting attachment, you can create custom setups with off-the-shelf lights to fit your needs. Once you do that, though, you can’t claim ISO compliance, and non-conforming parameters like lighting and aperture won't be reported. Matching your setup as closely as possible to a standard verifier will improve result correlations.

Grade reporting format

• The formal grade is written in a single line starting with the overall grade value followed by the aperture size, light wavelength, and lighting angle used.
• The verification grade is shown as a letter grade. The letter grade is based off a calculated numerical value that works like a GPA: a 4.0 is an “A,” 3.5 -2.5 is a “B,” and 2.5-1.5 is a “C.” 
• Using a different aperture size or lighting angle can give drastically different results.

	SBG	Verification
Reads Codes
Validates data
Code quality feedback
ISO parameter grades
Calibrated
Advanced code diagnostics
Uses ISO standard decode algorithm
Fixed angle lighting
Fully ISO compliants

With SBG, the reader can be calibrated to unify the cameras measurement of reflectivity levels and all ISO quality parameters are reported.

Unlike SBG, most barcode grading software such as Process Control Metrics (PCM) do not have a calibration process, follow the ISO grading algorithm requirements, or report every quality parameter. While barcode quality monitoring software results can provide a good idea of code quality, the results can also vary significantly between setups and hardware used.

Barcode grading software does give users an easy setup as it is usually a feature that is turned on to an existing reader. There are no specific lighting requirements and minimal mounting restrictions. Another benefit is cost, as most barcode reading companies include a form of barcode quality monitor software free of charge.

Traditional verifiers will test decoding first, and if that fails, they don’t continue the verification process. Cognex verifiers provide quality parameter grading even if a code fails decoding, giving you an idea of where to start improving code quality.

ISO compliant verification requirements at a glance

For 15426-2 2D Matrix Codes the verifier must meet the following requirements:

• Accommodate Reflectance Calibration based on two points (Rmax and Rmin)
• Collect reflectance measurements 20X past the quiet zones
• Establish a reference grayscale image and binarized image as described in ISO-15415
• Decode these images according to the reference decode algorithm spelled out in the bar code specification
• Report individual values for each of the grades spelled out in ISO-15415
• Determine and report an overall symbol grade
• Report the decoded data
• Must be able to conform to a conformance test using industry standard test card(s) (Rmin & Rmax +/- 5%) (Decodability +/- ,08) (Defect +/- ,08) as well as other manufacturer test symbol values on the test card.

For ISO 15426-1 a compliant verifier must meet the following requirements:

• Be calibrated with two calibration points (Rb & Rs)
• Collect reflectance measurements across multiple scans
• Create an SRP
• Analyze the SRP
• Report Individual SRP scan grades
• Determine an overall symbol grade based on averages of the individual SRP grades and include aperture and wavelength in the overall grade
• Report data
• Report all symbol characters (Function One, Code 128 encoding structure, etc.)
• Must conform to a conformance test using industry standard test card(s) (Rmin & Rmax +/- 5%) (Decodability +/- ,08) (Defect +/- ,08) as well as other manufacturer test symbol values on the test card.

Which option is right for my application?

Codes used in an industry with an application standard will list whether ISO compliant verification is required. If no application standard is attached to the codes being produced, consider what form vendors and customers are using and how results will be compared. It may be worth the extra expense to make sure codes are graded in a standardized process to reduce accuracy challenges down the road.

For some applications, speed and space restraints make using an ISO compliant verifier impossible. That's when many manufacturers turn to standards-based grading or a barcode quality software solution. Keep in mind the best barcode quality solution for you may not be one of these three options: it could be a combination of all three.