| Summary: | 碩士 === 國立交通大學 === 電信研究所 === 85 === Two significant building blocks in Color Flow Imaging systems
have been discussed in this study. The first part is dedicated
to clutter suppression. When the clutter is dominant as is
normal in clinical environment, FIR or IIR high-pass filters are
used to suppress the low-frequency clutter component. Simulation
results show that the transient effect can be mitigated even
when very short data sequence was available to the IIR filter
whose registers have been well-initialized. Another topic is
concerned with mean frequency estimation of Doppler blood flow.
Emphasis is placed on the AC (AutoCorrelation) and AR
(AutoRegressive) methods. The AC estimator is easy to implement
and superior to the conventional FFT estimator, but it lacks the
capability of distinguishing between blood flow and clutter. By
mapping phases to the spectral peaks of the backscattered
signal, an AR estimator has the advantage of reliable estimation
of blood flow without clutter suppression.
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