Skip to main content
. Author manuscript; available in PMC: 2016 Jul 1.
Published in final edited form as: IEEE Trans Ultrason Ferroelectr Freq Control. 2015 Jul;62(7):1225–1244. doi: 10.1109/TUFFC.2014.006775

Fig 9.

Fig 9

The change in the estimate produced by linear estimation, spectroscopy, and KV-MLE, due to truncation in the received signal, is investigated for a 2 kPa, 1 Pa·s simulated material. Cylindrical wave simulation is performed with the example shear wave traces in the upper left panel. Truncating this data set at various acquisition times has varying effects on the different estimators. In the upper right, the modulus is measured as a function of the total acquisition time. For linear and spectroscopic estimates, decreasing the acquisition time introduces a unpredictable bias in the measurement. Generally, there is an increase in the measured modulus, but this is not a monotonic trend. The viscosity estimate (lower left panel) is also severely impacted by decreasing acquisition time when spectroscopy is used. The lower right panel, shows a magnified view of modulus estimates for the acquisition time greater than 10 ms. The spectroscopy result approaches the correct value with increasing acquisition time. The KV-MLE estimate returns the correct modulus and viscosity for all acquisition times. Therefore, only the KV-MLE method is robust against signal truncation.