DocumentCode :
832733
Title :
Application of autoregressive spectral analysis to cepstral estimation of mean scatterer spacing
Author :
Wear, Keith A. ; Wagner, Robert F. ; Insana, Michael F. ; Hall, Timothy J.
Author_Institution :
FDA, Rockville, MD, USA
Volume :
40
Issue :
1
fYear :
1993
Firstpage :
50
Lastpage :
58
Abstract :
The problem of estimation of mean scatterer spacing in an object containing regularly spaced structures is addressed. An autoregressive (AR) spectral estimation method is compared with a conventional fast Fourier transform (FFT)-based approach for this task. Regularly spaced structures produce a periodicity in the power spectrum of ultrasonic backscatter. This periodicity is manifested as a peak in the cepstrum. A phantom was constructed for comparison of the two methods. It contained regularly spaced nylon filaments. It also contained randomly positioned glass spheres that produced incoherent backscatter. In an experiment in which this target was interrogated using broadband ultrasound, the AR spectral estimate offered considerable improvement over the FFT when the analysis gate length was on the order of the structural dimension. Advantages included improved resolution, reduction in bias and variance of scatterer spacing estimates, and greater resistance to ringing artifacts. Data were also acquired from human liver in vivo. AR spectral estimates on human data exhibited a decreased dependence on gate length. These results offer promise for enhanced spatial resolution and accuracy in ultrasonic tissue characterization and nondestructive evaluation of materials.<>
Keywords :
biomedical ultrasonics; spectral analysis; ultrasonic applications; ultrasonic materials testing; ultrasonic measurement; AR spectral estimate; NDT; analysis gate length; autoregressive spectral analysis; broadband ultrasound; cepstral estimation; human liver in vivo; incoherent backscatter; mean scatterer spacing; nondestructive evaluation; phantom; randomly positioned glass spheres; reduced variance; reduction in bias; regularly spaced nylon filaments; regularly spaced structures; resistance to artifacts; resolution; ultrasonic backscatter; ultrasonic tissue characterization; Backscatter; Cepstral analysis; Cepstrum; Fast Fourier transforms; Glass; Humans; Imaging phantoms; Scattering; Spatial resolution; Spectral analysis;
fLanguage :
English
Journal_Title :
Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on
Publisher :
ieee
ISSN :
0885-3010
Type :
jour
DOI :
10.1109/58.184998
Filename :
184998
Link To Document :
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