The inspection challenge
Foreign object contamination remains one of the most significant risks in food production. Contaminants can be introduced at multiple stages of processing, from raw material handling through cutting, mixing, packaging, and transport. Even well-controlled processes are vulnerable to unexpected inclusions.
Common challenges include:
Wide variation in contaminant size, shape, and material
Low contrast objects embedded within dense or overlapping products
High line speeds with limited tolerance for false rejects
Strong commercial and brand consequences of missed contamination
Traditional inspection methods often fail to provide sufficient coverage or consistency, particularly as product complexity and throughput increase.
Why in-line X-ray is used for foreign object detection
Inline X-ray inspection enables reliable detection based on material density and XRT attenuation, rather than surface appearance and photons of light reflecting back to a machine vision sensor. This allows foreign objects to be identified even when fully embedded within the product or packaging.
In food applications, X-ray inspection supports detection of:
Dense non-metallic contaminants examples include bone, glass and stones.
Metallic objects missed by conventional metal detection
Contaminants in packaged, wrapped, or overlapping products
X-ray systems are therefore widely adopted as a final control point where alternative technologies lack sufficient sensitivity or coverage.
Detector and signal chain requirements
Foreign object detection performance is fundamentally limited by detector behaviour, not algorithms alone.
Stability and repeatability
Small contaminants often sit close to the noise floor. Drift in detector gain, offset, or energy response can quickly reduce detection reliability or increase false rejects.
Low noise performance
A low noise signal chain is essential to:
Maintain sensitivity to small or low-contrast objects
Reduce reliance on aggressive image processing
Protect yield while enforcing safety thresholds
Uniform response across the detector
Non-uniform detector behaviour can create artefacts that mimic contamination or mask real inclusions, particularly in wide-belt or multi-lane systems.
Integration and lifecycle considerations
Food inspection systems must operate continuously in demanding production environments.
Key considerations include:
High throughput with short exposure times
Washdown and temperature-variable conditions
Minimal tolerance for downtime or frequent recalibration
Long operating lifetimes with predictable performance
For OEMs, detector stability directly affects commissioning effort, service cost, and customer confidence. Systems that perform well during acceptance testing but drift in production create ongoing operational risk.
The Sens-Tech approach to foreign object detection
Sens-Tech designs X-ray detectors with a focus on signal chain integrity, long-term stability, and predictable lifecycle behaviour, supporting reliable foreign object detection in food inspection systems.
By prioritising:
- Stable detector response over time
- Low noise and consistent energy behaviour
- Platform reuse across food inspection applications
Sens-Tech supports OEMs in building inspection systems that maintain detection performance while managing yield, uptime, and lifecycle risk.
This approach enables not just foreign object detection but also bone detection, sorting and fat analysis. Multiple applications can thus be delivered on a common detector foundation.
