IBEX has conducted studies to assess the sensitivity of our technology to contaminants with low absorption differences in chocolate bars.
In a typical test, having trained the system on 20 clean chocolate bars, a number of other bars were tested, of which some had been deliberately contaminated by inserting fragments of polycarbonate. Classic absorption contrast X-ray imaging is normally insensitive to such impurities, since polycarbonate and chocolate absorb X-rays very similarly.
IBEX technology successfully identified contaminated product, while taking normal product variation into account.
In non-contaminated bars, unusual bubbles and locally deformed volumes (*) were also detected, but correctly identified as being chocolate rather than plastic contaminant. (*) e.g. small regions deliberately melted but without contamination introduced.
Quantitative pass/fail thresholds may be set to reject contaminated products and flag up or reject product with unusual regions which are nonetheless chocolate.
The images were collected with magnification, in order to given higher spatial resolution and sensitivity to contaminants. Thus only two chunks of the chocolate bar are visible in the images. Data were collected using a micro-focus tungsten X-ray source operating at 80 kV, 3.9 W, using an IBEX-equipped CMOS flat-panel detector.