Fig. 2

Histograms of the AE waveform parameters AMP (amplitude, dB), COUN (counts, −), DURATION (duration, µs), SIGSTRNGTH (signal strength, nVs), ABSENERGY (absolute energy, aJ) and FREQPP2 (partial power in the range 100–200 kHz, %) for non-embolism AE datasets (first two rows) and embolism AE datasets (last two rows). Retained AE signals in embolism datasets based on upper level histogram thresholding corresponding to the number of embolism registered by µCT are highlighted in green, and non-retained AE signals in both datasets in red. The black dashed line indicates the average threshold value for each parameter, with scaling adjusted in the case of outliers