Expiry date reading and validation (OCR / DataMatrix)
The ink-jet lot and date lines on the carton are read by OCR and the DataMatrix code next to them is decoded. The two readings are compared with each other and with the production order; a carton with faint, smeared or wrong-content print is removed from the line.
The lot and date read, the match result and a readability score are written to the traceability record; a mismatched carton is pushed into the reject bin. Consecutive read failures raise a printer-maintenance warning on the operator display.
- 01 Infeed
- 02 Trigger
- 03 Read
- 04 Cross-check
- 05 Decide
Cartons arrive with the printed face up.
- OCR
- —
- DataMatrix
- —
- Matching chars
- —
Scenes are illustrative simulations; they are not customer references or performance guarantees.
Need
Ink-jet print is a dot matrix: characters are made of unconnected dots, and when the head is dirty dots go missing or smear. The print has low contrast on matt board and the carton may arrive rotated a few degrees on the belt; a wrong date must be caught even when it is printed cleanly.
Solution approach
A code reader with built-in illumination looks straight down at the carton; a short strobe removes motion blur. The code window is located from the carton edge, characters are segmented and read with a trained font, and the DataMatrix is decoded independently. The OCR result, the code content and the production order are compared three ways; any mismatch rejects the carton.
Process steps
- 01
Infeed
Cartons arrive with the printed face up.
- 02
Trigger
The photo-sensor sees the carton; the reader strobes and captures the image.
- 03
Read
Characters are segmented and read one by one; the DataMatrix code is decoded.
- 04
Cross-check
The OCR result, the code content and the production order are compared.
- 05
Decide
If every character is read and matches, the carton stays on the line.
Related applications
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