For beverage manufacturers, detecting and rejecting these defective products before packaging is a critical step in ensuring product quality, protecting brand reputation and meeting food safety compliance requirements. However, cap and fill level inspection on high-speed production lines is difficult to maintain consistently with manual visual inspection alone.For beverage manufacturers, detecting and rejecting these defective products before packaging is a critical step in ensuring product quality, protecting brand reputation and meeting food safety compliance requirements. However, cap and fill level inspection on high-speed production lines is difficult to maintain consistently with manual visual inspection alone.
Why Is High/Crooked Cap and Fill Level Inspection Challenging?
On high-speed filling lines, PET bottles pass through the inspection area at speeds of several hundred or even over a thousand bottles per minute. Caps may tilt in any direction, and fill levels may deviate due to filling fluctuations, bottle tilting or bubble interference.
Traditional manual visual inspection suffers from low efficiency and low job value, and human operators are prone to fatigue, making it difficult to consistently identify defects under high-speed production conditions.
In addition, fill level inspection faces additional complexities such as differences in product transparency, label occlusion on bottle bodies, and switching between different bottle types, further increasing inspection difficulty.
Summary of Issues
For PET-bottled beverage manufacturers, the detection of tilted caps and fill levels is a critical step in ensuring product quality and brand image. Traditional visual inspection methods struggle to meet the inspection requirements of high-speed production lines.
Recommended model
HISTOM Solution
HISTOM provides cap and fill level vision inspection solutions for the beverage industry. For different products including PET-bottled mineral water, juice, tea drinks and carbonated beverages, the system can be flexibly configured according to bottle type, line speed and inspection accuracy requirements, achieving 100% in-line inspection of defects including high caps, crooked caps, missing caps, broken tamper-evident rings and fill level deviations.
How Does a Cap and Fill Level Vision Inspection System Work?
1.Image Acquisition：
When PET bottles enter the vision inspection station, photoelectric sensors trigger high-precision industrial cameras to capture images of the caps and bottle bodies.
2.Cap Inspection：
The system processes the captured images, using the Canny operator to locate cap edges in the binarized image and the least squares method to fit the cap top contour line, enabling precise identification of defects such as high caps, crooked caps and missing caps.
Some systems employ a 4-camera combined inspection solution to accurately detect cap installation defects regardless of the direction of cap tilt.
3.Fill Level Inspection：
The system uses the bottle's support ring line as a reference and applies line-finding tools to locate the fill level line in the inspection area, determining whether the fill level is too low or too high based on the distance between the two lines.
For special scenarios such as liquid level fluctuation or bubbles, advanced inspection systems can achieve stable identification through algorithmic compensation.
4.Defect Rejection：
When cap or fill level abnormalities are detected, the system sends a signal to the rejection mechanism to automatically remove defective products and trigger an alarm.
