Capacitance Tomography (ECT) for Imaging Inside Sealed Packaging
Without opening the box, image the distribution of items inside a sealed package from permittivity contrast — demonstrating the potential of ECT for missing-item detection, foreign-object identification and more on packaging lines.
Follow us on WeChat
Scan with WeChat to follow for product updates and technical articles.
Background
Packaging lines often need to confirm whether items inside a box are complete, whether anything is mis- or under-packed, and whether foreign objects are present — but opening boxes for spot checks both breaks the seal and covers only a tiny fraction of products. X-ray can see through but involves radiation protection and high cost. Electrical Capacitance Tomography (ECT) images the in-box distribution without opening or radiation, by exploiting the permittivity contrast between materials, offering a lightweight technical route for this kind of inspection.
Technical challenges
- Permittivity contrast between items inside a box is limited; weak signals must be amplified by a high-sensitivity front-end and reconstruction algorithm
- Fast line cadence requires single-frame imaging and decision in milliseconds
- Box size and placement vary, so the electrode array must balance adaptability and consistency
- Metal packaging or metal contents shield the electric field — only applicable to non-metallic (plastic, paper, textile, liquid, etc.) packaging
Demonstration
Based on the ECT system, a non-contact electrode array is placed outside the package; the in-box capacitance distribution is acquired and a 2D / 3D image is reconstructed in real time. This video is a lab-stage imaging demonstration: as the placement of items inside the box changes, the reconstructed image shows the position and any missing contents in sync, validating the feasibility of ECT “seeing into” a sealed box.
Value
- Missing-item detection: missing or misplaced contents form an identifiable empty region in the image
- Foreign-object identification: foreign objects with clearly different permittivity can be distinguished
- Non-destructive, radiation-free: no box opening, no ionising radiation — suitable for 100% online inspection rather than spot checks
- Customisable: the electrode array and algorithm can be customised to the specific box type, material and line cadence
This case is a technology-capability demonstration / proof of concept showing the potential of Electrical Capacitance Tomography (ECT) in packaging inspection. For a solution assessment targeting a specific line, contact us.
