Expiry / production date verification (OCR)
The lot number, production date and expiry date lines printed on the carton face are imaged by a side-view camera. Characters are read one by one and each line is compared with the batch record; a mismatching or unreadable print is rejected.
The lot and date lines read are written to the batch record per carton together with the match result; a mismatching carton is diverted into the reject bin by the flap, and the operator display shows the read and expected values side by side.
- 01 Infeed
- 02 Acquire
- 03 OCR read
- 04 Compare
- 05 Decide
Closed cartons travel with their printed face towards the camera.
- Lot no.
- —
- Expiry
- —
- Lines matched
- —
Scenes are illustrative simulations; they are not customer references or performance guarantees.
Need
Inkjet print is made of dots; a clogged nozzle, a shifted character and the embossed pattern of the carton face distort the letters. The lines must be read at line speed within a short time window and must not only be legible but identical to the value in the batch record.
Solution approach
A smart camera with integrated ring light looks squarely at the printed face; the photo-sensor triggers and after an encoder delay the shot is taken with the print field in frame. The field is located with a fixed template, characters are segmented and read with a dot-matrix font. Each line is compared with the lot and date values in the batch record; one differing character rejects the carton.
Process steps
- 01
Infeed
Closed cartons travel with their printed face towards the camera.
- 02
Acquire
The photo-sensor sees the carton; the ring light strobes and the print field is captured.
- 03
OCR read
The characters of the three lines are segmented and read one by one.
- 04
Compare
Each line read is compared with the value in the batch record.
- 05
Decide
If all lines match the carton continues; otherwise the diverter opens.
Related applications
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