Lung sound localization using array of acoustic sensors

This paper presents a localization algorithm to detect lung sounds using a circular array of microphones. We use the natural basis functions of propagation waves in height invariant wavefields to form a spatial minimum variance (MV) problem in eigen space. We also derive a Nyquist criteria for localizing sources within a circular region. This Nyquist criteria shows that the radius of the region where sources can be localized is inversely proportional to the frequency of sound. The modified Nyquist criteria can be used for determining the number of sensors required for a given frequency range and radius of region for which sources need to be localized. The results are corroborated by computer simulations.

[1]  D.E. Dudgeon,et al.  Fundamentals of digital array processing , 1977, Proceedings of the IEEE.

[2]  G. Stewart.  On the Perturbation of Pseudo-Inverses, Projections and Linear Least Squares Problems , 1977 .

[3]  N Gavriely,et al.  Spectral characteristics of normal breath sounds. , 1981, Journal of applied physiology: respiratory, environmental and exercise physiology.

[4]  D A Rice,et al.  Sound speed in pulmonary parenchyma. , 1983, Journal of applied physiology: respiratory, environmental and exercise physiology.

[5]  Yoram Bresler,et al.  On the number of signals resolvable by a uniform linear array , 1986, IEEE Trans. Acoust. Speech Signal Process..

[6]  W. Kummer,et al.  Basic array theory , 1992, Proc. IEEE.

[7]  R. Kress,et al.  Inverse Acoustic and Electromagnetic Scattering Theory , 1992 .

[8]  F. Li,et al.  Performance analysis for DOA estimation algorithms: unification, simplification, and observations , 1993 .

[9]  M Nissan,et al.  Spectral characteristics of chest wall breath sounds in normal subjects. , 1995, Thorax.

[10]  Darren B. Ward,et al.  Beamforming for a source located in the interior of a sensor array , 1999, ISSPA '99. Proceedings of the Fifth International Symposium on Signal Processing and its Applications (IEEE Cat. No.99EX359).

[11]  Laurence J. Jacobs,et al.  Guided circumferential waves in layered cylinders , 1999 .

[12]  M Kompis,et al.  Acoustic imaging of the human chest. , 2001, Chest.

[13]  Rodney A. Kennedy,et al.  Bounds on the Spatial Richness of Multipath , 2002 .

[14]  Roger W. Johnson,et al.  Exploring Relationships in Body Dimensions , 2003 .

[15]  Thushara D. Abhayapala,et al.  Coherent broadband source localization by modal space processing , 2003, 10th International Conference on Telecommunications, 2003. ICT 2003..

[16]  Hansen A. Mansy,et al.  Detection of Pneumothorax by Computerized Breath Sound Analysis , 2004 .

[17]  J. Rose,et al.  Guided wave propagation in an elastic hollow cylinder coated with a viscoelastic material , 2004, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[18]  Jun Ma,et al.  SH wavefields in cylindrical double-layered elastic media excited by a shear stress source applied to a borehole wall , 2005 .

[19]  S. Charleston-Villalobos,et al.  Respiratory acoustic thoracic imaging (RATHI): Assessing deterministic interpolation techniques , 2004, Medical and Biological Engineering and Computing.

[20]  S. Charleston-Villalobos,et al.  Acoustic Thoracic Images for Transmitted Glottal Sounds , 2007, 2007 29th Annual International Conference of the IEEE Engineering in Medicine and Biology Society.

[21]  H. Mansy,et al.  Boundary element model for simulating sound propagation and source localization within the lungs. , 2007, The Journal of the Acoustical Society of America.