Ultrasonic detection:
The principal is based on the fact that water and rubber have
similar dencity, and conduct sound waves very well, whereas
air does not. The ultrasound emitted from one probe is directed
through the tyre, to a receiving probe. both probes move together
across the tyre's width and back, all the time the tyre is
spinning so eventually you build up a picture of the relative
density of the whole tyre. The effect looks very much like
an x-ray but it is instant and totally safe. The technology
we use is similar but far in advance to ultrasonic baby scanners
(you can actually understad the image!) This ia a world patented
technology
