5. Sensitivity principle: accessible quantities

5.1 Intrinsic versus extrinsic property

The elastic wave transducer meets two requirements: to separate the sensor response from all the echoes generated by the environment (clutter) and to introduce a signature representative of the measured quantity (figure 2 ). The approach we have chosen to distinguish the sensor from the environment consists in delaying the temporal response of the former beyond that of the latter, taking into account the sensitivity of the receiver. Thus, for a receiver with insufficient sensitivity to detect a large target – a few hundred...