| 摘要 |
<p>Methods and apparatus relate to ultrasound measurement of a dimension such as the thickness (11) of an item (12) which may be worn over time by contact with an item (14). An ultrasonic transceiver (18) couples ultrasound into the item (12). Outgoing ultrasound i results in echos r returning to the transceiver (18). This allows calculation of time of flight to yield a value for the thickness (11). In the examples prescribed, the measurement is repeated a plurality of times in a specified period to extract a dimension from each received signal. Information extracted from the plurality of received signal is used to produce a single value indicative of the dimension of the item (12) over the specified period.</p> |
