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.
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.
