Print defect inspection on glossy packaging film
The packaging film advances from the unwinder to the line-scan station. Print shape is compared with a reference under directional light; the missing mark region is masked and the defective length is recorded with its position.
The defect mask and web position are recorded in the PLC; the defective length is flagged for subsequent separation and sent to the operator display.
- 01 Positioning
- 02 Acquire
- 03 Analyse
- 04 Decide
Printed film flows from the roll into the inspection span.
- Missing print area
- —
- Defective regions
- —
Scenes are illustrative simulations; they are not customer references or performance guarantees.
Need
Specular reflections on glossy film obscure printed strokes. Web tension and lateral motion show the same mark at different positions in each image, making direct comparison difficult.
Solution approach
An overhead line-scan camera and oblique bar light image the print as the film moves. Mark position is aligned first; missing areas in contours and filled regions compared with the reference template are extracted as a mask.
Process steps
- 01
Positioning
Printed film flows from the roll into the inspection span.
- 02
Acquire
The line-scan camera images the mark under directional lighting.
- 03
Analyse
The aligned mark is compared with the reference template.
- 04
Decide
Missing print is masked and the defective length is recorded.
Related applications
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