Inverse methods in the reconstruction of acoustical impedance profiles

Schwetlick, Horst

doi:10.1121/1.389262

Cited by 16 publications

(5 citation statements)

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“…We utilize Goupillaud solution cited in Ware and Aki,12) in which the readers can find the algorithm has equivalent meanings to solve the integral equation of Eq. (13). The authors strongly recommend the readers to refer their original paper, although we summarize the algorithm in the following section in connection with the application for measurements of ear canal area functions.…”

Section: Introductionmentioning

confidence: 99%

Acoustic impedance measurement on normal ears of children.

Okabe

Tanaka

Hamada

et al. 1988

J. Acoust. Soc. Jpn. (E), J Acoust Soc Jpn E

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In order to provide the fundamental knowledge on outer and middle ear of children, acoustic impedance measurements were performed on 205 subjects. They ranged from 3 years old to 11 years old and had normal hearing. We utilized the acoustic inverse method for reconstruction of the ear canal area functions.The results show (a) the children have smaller ear canal radius than the adults and (b) the ear canal volume and the ear canal radius increase as a function of the age. The acoustic impedance at the eardrum were calculated from the reconstructed area function of the ear canals and the measured reflection data. It is shown that (c) mean resistance of the eardrum impedance remains between 300 and 350 cgs acoustic ohms above 2 kHz, and the value is not so much different from the reported data on the adults. On the other hand, (d) middle ear of the children has small compliance and its values approach to the adults data as the age increases. This is evident in lower frequencies below 1 kHz.

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Section: Introductionmentioning

confidence: 99%

Acoustic impedance measurement on normal ears of children.

Okabe

Tanaka

Hamada

et al. 1988

J. Acoust. Soc. Jpn. (E), J Acoust Soc Jpn E

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“…We solve the coupled hyperbolic equations (5) and (6) by the method of characteristics. Our basic approach is similar to the inverse scattering approach of Santosa and Schwetlick (1982), Schwetlick (1983) and Bube and Burridge (1983).…”

Section: Wave Scattering Methodsmentioning

confidence: 99%

Wave Scattering Deconvolution by Seismic Inversion*

Sarwar

Smith

1987

Geophysical Prospecting

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We propose a wave scattering approach to the problem of deconvolution by the inversion of the reflection seismogram. Rather than using the least‐squares approach, we study the full wave solution of the one‐dimensional wave equation for deconvolution. Randomness of the reflectivity is not a necessary assumption in this method. Both the reflectivity and the section multiple train can be predicted from the boundary data (the reflection seismogram). This is in contrast to the usual statistical approach in which reflectivity is unpredictable and random, and the section multiple train is the only predictable component of the seismogram. The proposed scattering approach also differs from Claerbout's method based on the Kunetz equation. The coupled first‐order hyperbolic wave equations have been obtained from the equation of motion and the law of elasticity. These equations have been transformed in terms of characteristics. A finite‐difference numerical scheme for the downward continuation of the free‐surface reflection seismogram has been developed. The discrete causal solutions for forward and inverse problems have been obtained. The computer algorithm recursively solves for the pressure and particle velocity response and the impedance log. The method accomplishes deconvolution and impedance log reconstruction. We have tested the method by computer model experiments and obtained satisfactory results using noise‐free synthetic data. Further study is recommended for the method's application to real data.

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“…이중 고해상도 의 신호를 얻기 위한 Chirp sonar는 LeBlanc과 Mayer 연구진 에 의해 Chirp sonar 시스템이 개발된 후 해저 지형의 표층 및 매설물 탐지, 퇴적물의 특성 분석 등 다양한 분야에서 응용 연 구되고 있다 (Tolsma, 2004 (Lurton, 2002;Tolsma, 2004;Rakotonarivo et al, 2011;Schwetlick, 1983). 공진 주파수로 변조된 수신 신호에 포락선 검파를 하는 일반적인 지층의 분석 방법은 반사된 sonar 신호 의 펄스폭에 따른 거리 해상도의 한계가 존재한다 (Lurton, 2002;Tolsma, 2004).…”

Section: 해저지층탐사를 위하여 일반적으로 사용되는 송신 신호는unclassified

“…1917년 I. Schur에 의해 제안된 Schur 알고리즘은 (Kailath, 1987) Multirate 신호처리 (Vetterli, 1987;Vaidyanathan, 1993), 역 산란 문제 (Bruckstein and Kailath, 1987), 음성 신호처리 (Markel and Gray, 1976), 광 산란 필터 (Dowling and MacFarlane, 1994), 이종현․이재일․배진호 지층 Profiling (Markel and Gray, 1976), 그리고 해수의 음향속도 Profiling (Schwetlick, 1983) (Hamilton and Blackstock, 1998;Lee, 1993).…”

Section: 해저지층탐사를 위하여 일반적으로 사용되는 송신 신호는unclassified