Ultrasound probes

A method for detecting electromagnetic interference in ultrasound imaging of a substrate, comprising the steps of:

• using an ultrasound transducer to send out a plurality of ultrasound signals into a substrate, wherein the plurality of ultrasound signals are separated in time by a pulse repetition period;
• detecting return signals for each of the plurality of ultrasound signals and recording the return signals as signal traces;
• rectifying each of the signal traces to produce a plurality of rectified traces;
• identifying, at each time sample, a minimum value across all of the plurality of rectified traces;
• deriving, for each of the plurality of rectified traces, a difference between a value at each time sample and the minimum value at each time sample;
• and
• where the difference exceeds a threshold in any of the rectified traces, marking the value for that time sample in that rectified trace as interference.