V.V.Krizhanovskii, V.V.Krizhanovskii (jr.) Studying the efficiency of using the autoregressive spectral estimation of angular spectra of acoustic fields for non-invasive detection of artifacts in bounded objects |
Acoustic bulletin, Vol. 15 ¹ 3, (2012) |
| The paper deals with discussing of the efficiency of algorithms for estimation of the angular spectra of acoustic signals in small-sized objects. It is considered that due to the limited wave size, they should use for this purpose the small-sized antennas with a structure providing the possibility of using of simple and efficient computational procedures. The algorithms for estimation of the angular spectra by means of the linear discrete equidistant antenna are proposed. The main attention is paid to the two-element antenna and autoregressive (AR) algorithm. On the base of the model studies, the higher efficiency of AR estimation in comparison with the traditional procedure is shown. The structural features of the angular spectra of the signals from extended and lumped sources are distinguished. Changes of the structure of angular spectra are shown for the cases of variation of the sound speed in propagation medium and appearance of the layer of acoustic heterogeneity. The efficiency of use of AR estimation for spatial resolution of point signal sources is considered. The presented experimental results of determining of the angular spectra of the voice signals and respiratory wheezing confirm the efficiency of AR estimation for identifying and localization of such sources. |
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KEY WORDS: sound speed, the lung parenchyma, extended and point acoustic sources, autoregressive estimation, angular spectrum |
| TEXT LANGUAGE: Russian |