​​How to Choose the Right Barcode Verifier​

Barcode verifiers test both the image and data quality to grade a code's readability. To select the right model, you need to match the verifier's field of view, lighting, and optics to your application.

While many parameters, such as bar width growth, axial non uniformity, and quiet zone are used measure the accuracy of a code compared to requirements, other qualities—such as contrast and reflectance—affect the optics of barcode readers and how they “see” a code.  

Here are four questions to guide your selection:

1. What is your code size range?
   You need to know the size of the narrowest bar or smallest module, typically measured in mils (0.001 of an inch). Your verifier’s camera resolution, or minimum x-dimension, must be smaller than or equal to this measurement. Also consider the total size of your largest barcode. The verifier’s field of view must be large enough to capture the entire code, including the surrounding quiet zone.

   

2. What material are your codes printed on?
   The substrate affects how a barcode reader’s camera sees a code. To properly illuminate different surfaces, you need specific lighting angles. Most verification standards for 1D and 2D label-based codes specify 45-degree lighting. This angle makes sure light reflects off the label and back to the camera. For DPM codes on shiny, textured, or curved surfaces, you will likely need a verifier with 30-degree, 90-degree, or dome lighting options.

   

3. Do you have oddly shaped parts?
   If you work with small or unconventionally shaped parts, look for a verifier with an adjustable height stand. This feature makes it much easier to position the code correctly under the camera. If a symbol is in a recessed area, your verifier’s software should help to select a specific region for analysis.

   

4. What software features do you need?
   A verifier's software should both grade and diagnose problems in your printing process. The right software generates reports that grade against the relevant ISO and application standards, helping with compliance and quality. 

   

The most common barcodes, like the UPC codes on consumer goods, are 1D. To verify them correctly, it’s best to understand their type, size, and the standards that govern them, such as GS1 for general use and ISO 15416 for international compliance.

Only a verifier with the right lighting, optics, and software can accurately grade 1D codes according to ISO standards. Here’s what you need to consider:

• Lighting angle: To comply with ISO 15415, you must use a 45-degree lighting angle to verify codes printed on flat surfaces.
• Field of view: Your verifier’s field of view must be large enough to fit your largest 1D barcode and its required quiet zone.
• Minimum X-dimension: The verifier should accommodate the smallest element (bar or space) in your code. If it can't, the camera won’t capture the image with enough detail for accurate verification.
• Verifier style: For products with many different shapes and sizes, a verifier with an adjustable camera height gives added flexibility. For large labels or those with multiple barcodes, a desktop "box" style verifier with a wider field of view is a better choice.
• Software capabilities: Make sure the software is user-friendly, grades against ISO 15416, finds data formatting errors, and generates clear reports to help diagnose printing issues. 

2D barcodes hold much more information than 1D barcode, which makes them more challenging to verify. They often have higher failure rates due to their complexity. These codes are typically verified against standards like ISO 15415 or ISO TR 29158 (AIM DPM).

Remember, you cannot verify a code with software alone and need a dedicated 2D barcode verifier with a camera. To consider these factors for a successful setup:

• Lighting angle: The 45-degree angle is standard for label-based codes. For DPM codes, a verifier with 30-degree and 90-degree lighting options is necessary to illuminate many surfaces, like reflective materials.
• Field of view: The verifier needs a field of view large enough to capture the entire 2D barcode and its quiet zone.
• Minimum X-dimension: The verifier must be able to read the smallest module (cell or space) in your code to perform an accurate verification.
• Verifier style: An adjustable-height verifier is great for parts with varying shapes and sizes. A desktop "box" verifier works well for large labels or multiple codes that need to be verified at the same time.
• Software capabilities: The software must be able to grade against ISO 15415, report on data formatting, and help you diagnose printing issues effectively.

Direct part mark (DPM) codes are marked directly onto a part's surface. These codes can be challenging to read because the marking method (like dot peen or laser etching) can create low-contrast or inconsistent marks. The surface itself might be shiny, rough, or curved.

Because of those challenges, controlling the lighting and background is crucial. DPM codes are verified against the AIM DPM standard. Here’s what you need:

• Lighting angle: The verification standard for DPM – ISO TR 29158 (AIM DPM) – is very similar to ISO/IEC 15415. An exception is that the standard allows for 30-degree and 90-degree lighting in addition to the standard 45-degree angle. This flexibility helps properly illuminate codes on tough surfaces, like curved or reflective parts.
• Field of view: Your verifier must have a field of view large enough to span the entire DPM code and its quiet zone.
• Minimum X-dimension: The verifier’s camera needs to have a resolution fine enough to capture the smallest module in your code for the best grade.
• Verifier style: An adjustable-height verifier is useful for parts of different shapes and sizes, especially those with recessed areas. A desktop verifier is better for larger parts or multiple codes.
• Software capabilities: The software should grade against the AIM DPM standard, show data formatting errors, and generate reports that help troubleshoot any issues with the marking process.