| 摘要 |
<p>Structural features (107, 108, Fig 1) below the surface of an object are imaged using ultrasound pulses sent and then received from reflections. One or more signals received are processed to recognise a reflection caused by a first structural feature (107, Fig 1) and a reflection caused by another structural feature (108, Fig 1) at least partly behind the first feature, deeper in the object. Each reflection is associated with a relative depth at which the reflection occurred. An image (505, Fig 5a) is generated from the recognised reflections that represents the structural features and their relative depths. A user adjustable time gate may be applied to the received signal, and the receiver unit may be configured to receive multiple reflections of a single transmitted pulse while in a stationary position. The transmitted pulse may have a particular shape suitable for transmission in the object, and a match filter may be used to recognise it. A handheld device (801, Fig 8) may have a matrix array of transducers and use a dry coupling medium.</p> |
