Application guide
How does camera-based fill-level inspection work?
An industrial camera captures the container at a controlled point on the line. Backlighting, front lighting or another suitable optical arrangement exposes the visible product boundary, and the system compares the measured level with recipe-controlled limits. A high, low, missing or uncertain result can then be rejected or used to stop the line.
The method is most straightforward when the fill boundary is visible through the container. Tinted plastic, embossed glass, opaque products, labels, foam and bubbles can change what the camera sees, so representative production trials are essential.
Vision inspection and checkweighing answer different questions
A camera can identify a visible liquid level and may reveal gross underfill, overfill, foam or missing product. A checkweigher measures total pack mass and can be more appropriate when the container is opaque or the product boundary cannot be seen. Neither method automatically proves the exact dispensed volume unless the wider process and product properties support that conclusion.
Some lines benefit from both: vision confirms the visible level, cap and presentation while a checkweigher controls net-weight risk. Oxford Vision Systems will recommend the sensing principle that matches the defect rather than forcing every application into a camera check.
Fill and closure checks that can share an inspection station
- High, low, missing or grossly inconsistent visible fill level
- Liquid boundary position within a permitted band
- Foam or headspace condition where contrast is sufficient
- Cap presence, height, skew and approved colour
- Tamper-band or visible closure-feature presence
- Bottle, jar or container presence and orientation
- Label and date-code checks from complementary views
- Tracking to a confirmed automatic reject device
Design for the difficult production conditions
Transparent liquids can need backlighting; dark products may need front or transmitted illumination. Curved glass can create lensing and reflections. Carbonated products may foam after filling, while viscous products can coat the sidewall and obscure the true boundary. Line vibration and bottle spacing also affect measurement repeatability.
The feasibility test should include normal temperature, colour, foam, meniscus and container variation. Thresholds are then set around the approved process range with a defined policy for borderline or no-measure results.
Where should the inspection be installed?
The preferred location is usually after the fill has settled enough to be measured and before downstream equipment hides the area of interest. If the same station checks caps, it may sit after capping. Conveyor stability, guide position, line speed and reject distance determine the final arrangement.
Information needed to assess feasibility
- Container drawings or samples across every size and colour
- Products representing the lightest, darkest, clearest and most opaque fills
- Approved low, nominal and high examples
- Foam, bubbles, coating and settling behaviour at production speed
- Label and sleeve positions relative to the intended view
- Conveyor video, pitch, speed and available reject distance
- Required relationship with filler feedback or checkweighing
Related bottle-line controls
Combine fill-level inspection with bottle inspection, cap and closure checks, date-code inspection and beverage-line inspection.