A comparison of IIR initialization techniques for improved color Doppler wall filter performance

The performance of exponential initialization, a novel infinite impulse response (IIR) filter initialization technique, was compared with that of three existing initialization techniques, zero, step, and projection in the context of color Doppler wall filtering. A simulation which uses a statistical estimation approach, was developed to evaluate the performance of each of the initialized IIR filters in terms of their effect on frequency estimation and tissue echo suppression. The results show that the wall filters examined here introduce a degree of bias into Doppler frequency estimation which depends on the IIR initialization technique, the filter cutoff frequency, the number of Doppler samples in the sample volume, and the input signal statistics. In addition, the realized frequency response is compromised relative to the desired steady state IIR response. Exponential initialization is shown to exhibit the least frequency estimate bias