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Application // 02

OCR/OCV and code inspection for production lines

Best-before date, batch code and barcode checks on cartons, bottles, cans, pouches and labels, whatever coder printed them.

Technical review: Frank GuoReviewed

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// Short answer

A camera station can read best-before dates, batch codes and barcodes on each pack and compare them with the values expected for the run. OCR reads the characters; OCV checks that the expected text is present, complete and legible. It works when the code lands in a predictable area with consistent contrast. Reading a barcode is not the same as grading its print quality. We confirm what is achievable on your own coded samples first.

// What it checks

What a code inspection station checks

Four checks cover most coding faults. Which you need, and how strict the limits are, is set at the sample test.

01 // OCR

Read the code (OCR)

Reads the printed characters so the code can be logged or passed to a traceability system.

NeedsConsistent font, size and print contrast
02 // OCV

Verify the expected text (OCV)

Compares the printed date and batch code with the string expected for the run.

NeedsThe expected string for every run
03 // Print

Code print quality

Faint, broken or smeared characters, and codes printed outside their area.

NeedsGood and poor print samples to set limits
04 // Barcode

Barcode and 2D code reading

Decodes barcodes and 2D codes such as Data Matrix and QR, and checks the content matches the product.

ScopeReading only, not print-quality grading

OCR, OCV, reading and grading compared

OCR, OCV, barcode reading and barcode grading compared
CapabilityQuestion it answersWhat you getFrom us
OCRWhat is printed here?The text as read, for logging or comparison.Offered
OCVIs the expected text printed and legible?Pass or fail against the expected string.Offered
Barcode readingDoes the code decode with the right content?The decoded data, matched to the product.Offered
Barcode gradingHow good is the print, to a formal standard?A quality grade from a dedicated verifier.Not offered

Coding technologies we check

Inkjet

Characters made of dots; ink spread changes their look, so we test codes from your own coder.

Thermal transfer

Ribbon print on film or labels; worn print heads leave white lines through characters.

Laser

Marks the material or its coating; contrast depends on the material.

We inspect the output of the coder you already run. We do not sell or service coders.

// Limits

Where code inspection stops

We agree these boundaries before a project starts, so nobody expects the camera to do what it cannot.

Not covered by this station

  • Formal barcode grading. Reading shows a code decodes with the right data; a formal print-quality grade needs a dedicated verifier.
  • Codes out of view. Codes underneath, under a fold or on a freely rotating container cannot be read from one fixed view.
  • Wrong data at source. If the recipe and the coder both hold the wrong date, they agree and the error passes.

Works reliably when

  • The code lands in a predictable area. Stable presentation keeps the code inside the camera's view.
  • Contrast is stable. Shielded station lighting, chosen for shiny films or curved surfaces.
  • The expected string arrives automatically. From the recipe, coder or PLC, not typed in at each changeover.
// Station layout

How a code inspection station is laid out

Plan view of a typical station after the coder. The real layout follows the site survey.

[Schematic]Plan view · not to scale

Swipe sideways to see the whole drawing →

Plan view of a code inspection station Packs pass the existing coder, then a trigger sensor, then a camera inside a dome light that reads the printed code. The camera exchanges the expected code and the result with the line PLC, and a reject air jet removes packs whose code is wrong. PRODUCT FLOW → [1] CODER (EXISTING) [2] TRIGGER SENSOR [3] CAMERA + LENS [4] DOME LIGHT LINE PLC / RECIPE EXPECTED CODE ⇄ RESULT [5] REJECT (AIR JET)
[1] Coder: your existing inkjet, thermal transfer or laser coder.
[2] Trigger sensor: tells the station a pack has arrived.
[3] Camera: images the code area; resolution is chosen from the smallest character detail.
[4] Dome light: even light that reduces glare on film and curved packs.
[5] Reject: removes failed packs; the PLC tracks each one and supplies the expected code.
// Pass and reject[Illustrative examples]

What a pass and a reject look like

Illustrations of three common outcomes, not images from a real line. How faint a character may be before it fails is agreed with you during the sample test.

EXP DD MMM YYLOT ABCCODE AREA
PASS
Example // Carton end

Code correct

Date and lot code are complete and legible, and match the expected text for the run.

OCV: MATCHACTION: PASS
EXP DD MMM YYLOT ABCBROKEN CHARACTERS
FAINT
Example // Inkjet on film

Characters broken

Some characters are faint or missing dots, below the agreed print limit.

PRINT: ✗ BELOW LIMITACTION: REJECT
EXP DD MMM YYLOT ABDEXPECTED: ABCCODE AREA
MISMATCH
Example // Bottle label

Wrong lot code

The lot code does not match the run: the typical fault when the coder was not updated at changeover.

OCV: ✗ WRONG CODEACTION: REJECT / ALARM
// Line interface

What we need to know about your line

These conditions decide the station design. None of them has a fixed answer; each is confirmed on site or during the sample test.

Line conditions for a code inspection station
ConditionWhat we need to knowWhy it mattersConfirmed during
Coder and modelCoder type and model, and whether it can send out the printed string.Decides lighting and whether the expected string can come from the coder.Site survey
Expected data sourceWhere the correct date and batch code are held: recipe, coder, PLC or a production system.OCV needs to know what should be printed for every run.Design review
Code position and materialWhere the code sits, and the material and colour underneath.Sets camera angle, lighting and the number of views.Sample test
Line speed and spacingPacks per minute and the gap between them.Sets exposure and trigger method.Site survey
PLC and rejectPLC make and model, spare I/O or network ports, existing reject.Decides how results and the expected string are exchanged, and whether read results are logged.Design review
// Acceptance

How the station is accepted

False rejects and missed defects pull against each other. We define both, and how they are measured, before FAT and SAT.

01

False reject rate

The share of correctly coded packs rejected, measured on agreed good samples at line speed. The acceptable level is agreed per project.

02

Missed defect rate

The share of wrong, missing or illegible codes that pass, measured with seeded faulty codes. The target is set with you.

03

Changeover handling

A test that the expected string updates at every product or date change.

// Before we start

What to prepare for the sample test

We check codes from your own coder before proposing a station. We confirm quantities and shipping with you first.

Sample preparation guide

Good samples

Packs coded on the production coder, covering each material and code position.

Defective samples

Faint, smeared, incomplete and wrong codes, clearly marked.

Code specification

Date and batch code format, example strings, and the barcode types used.

Line information

Coder and PLC models, line speed, and where the expected data is held.

// FAQ

Code inspection questions

What is the difference between OCR and OCV?
OCR reads the characters and reports what is printed. OCV starts from the text that should be printed and checks that it is there, complete and legible. For date and batch codes, OCV is usually the right check, because the line already knows what the code should say.
How can expiry dates and batch codes be verified on a bottling line?
A camera after the coder images each code. The station receives the expected date and batch code from the recipe, coder or PLC, compares it with the print, and has the PLC reject any bottle whose code is wrong, missing or illegible.
Is barcode reading the same as barcode quality verification?
No. Reading confirms that a code decodes and its content is right. Verification, or grading, measures print quality against a formal standard with a dedicated verifier. We offer reading, not formal grading.
Which software runs the inspection?
We build stations on HIKROBOT VisionMaster, whose OCR HIKROBOT describes as deep-learning based, with code reading covering 1D and 2D codes (vendor-stated). We build on it as an independent integrator; this website does not claim any official HIKROBOT partnership or distributor status.

Sources

  1. HIKROBOT VisionMaster product page (OCR and code reading) (vendor page, checked 2026-09-24)
// Code inspection

Request an assessment for this application

Tell us which codes you print and where the correct values are held, and send good and bad samples. We will tell you what a station can check.

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