The inverse problem of the noninvasive measurement of the shape of an acoustical duct in which one-dimensional wave propagation can be assumed is examined within the theoretical framework of the governing Klein–Gordon equation. Previous deterministic methods developed over the last 40years have all required direct measurement of the reflectance or input impedance but now, by application of the methods of inverse quantum scattering to the acoustical system, it is shown that the reflectance can be algorithmically derived from the radiated wave. The potential and area functions of the duct can subsequently be reconstructed. The results are discussed with particular reference to acoustic pulse reflectometry.

1.
B. J.
Forbes
,
D. B.
Sharp
,
J. A.
Kemp
, and
A.
Li
, “
Singular system methods in acoustic pulse reflectometry
,”
Acta. Acust. Acust.
89
,
743
753
(
2003
).
2.
J.
Schroeter
and
M. M.
Sondhi
, “
Techniques for estimating vocal-tract shapes from the speech signal
,”
IEEE Trans. Speech Audio Process.
2
,
133
150
(
1994
).
3.
M. R.
Schroeder
, “
Determination of the geometry of the human vocal tract by acoustic measurements
,”
J. Acoust. Soc. Am.
41
,
1002
1010
(
1967
).
4.
P.
Mermelstein
, “
Determination of the vocal tract shape from measured formant frequencies
,”
J. Acoust. Soc. Am.
41
,
1283
1294
(
1967
).
5.
M. M.
Sondhi
and
B.
Gopinath
, “
Determination of vocal tract shape from impulse response at lips
,”
J. Acoust. Soc. Am.
49
,
1867
1873
(
1971
).
6.
M. M.
Sondhi
and
J. R.
Resnick
, “
The inverse problem for the vocal tract: Numerical methods, acoustical experiments and speech synthesis
,”
J. Acoust. Soc. Am.
73
,
985
1002
(
1983
).
7.
I.
Marshall
, “
Acoustic reflectometry with an arbitrarily short source tube
,”
J. Acoust. Soc. Am.
91
,
3558
3564
(
1992
).
8.
I.
Marshall
, “
Impedance reconstruction methods for pulse reflectometry
,”
Acustica
76
,
118
128
(
1992
).
9.
D. B.
Sharp
, “
Increasing the length of tubular objects that can be measured using acoustic pulse reflectometry
,”
Meas. Sci. Technol.
9
,
1469
1479
(
1997
).
10.
D. B.
Sharp
and
D. M.
Campbell
, “
Leak detection in pipes using acoustic pulse reflectometry
,”
Acust. Acta Acust.
83
,
560
566
(
1997
).
11.
J. A.
Kemp
,
J. M.
Buick
, and
D. M.
Campbell
, “
Practical improvements to acoustic pulse reflectometry
,”
Proceedings of the International Symposium on Musical Acoustics
Perugia, Italy
2001
, No.
2
, pp.
391
394
.
12.
J. M.
Buick
,
J. A.
Kemp
,
D. B.
Sharp
 et al., “
Distinguishing between similar tubular objects using pulse reflectometry: A study of trumpet and cornet leadpipes
,”
Meas. Sci. Technol.
13
,
750
757
(
2002
).
13.
A.
Li
,
D. B.
Sharp
, and
B. J.
Forbes
, “
Improving the high frequency content of the input signal in acoustic pulse reflectometry
,”
Proceedings of the International Symposium on Musical Acoustics
,
Perugia, Italy
,
2001
, pp.
391
394
.
14.
B. J.
Forbes
,
J. A.
Kemp
, and
D. B.
Sharp
, “
Pulse reflectometry as an acoustical inverse problem: Regularisation of the bore reconstruction
,”
Proceedings of the First Pan-American/Iberian Meeting on Acoustics incorporating the 144th Meeting of the A.S.A
,
Cancun, Mexico
,
2002
.
15.
A.
Li
,
D. B.
Sharp
,
B. J.
Forbes
, and
J. A.
Kemp
, “
The problem of DC offset in the measurement of impulse response using acoustic pulse reflectometry
,”
Proceedings of the Institute of Acoustics
,
Salford, UK
,
2002
, Vol. 24, No.
2
.
16.
A.
Li
and
D. B.
Sharp
, “
Reducing the source tube to improve the bandwidth of acoustic pulse reflectometry
,”
Proceedings of the Stockholm Music Acoustics Conference (SMAC)
,
Stockholm, Sweden
,
2003
.
17.
P.
Ladefoged
,
R.
Harshman
,
L.
Goldstein
, and
L.
Rice
, “
Generating vocal tract shapes from formant frequencies
,”
J. Acoust. Soc. Am.
64
,
1027
1035
(
1978
).
18.
L.-J.
Boë
,
P.
Perrier
, and
G.
Bailly
, “
The geometric vocal tract variables controlled for vowel production: Proposals for constraining acoustic-to-articulatory inversion
,”
J. Phonetics
20
,
27
38
(
1992
).
19.
J.
Schoentgen
and
S.
Ciocea
, “
Kinematic formant-to-area mapping
,”
Speech Commun.
21
,
227
244
(
1997
).
20.
P.
Badin
,
D.
Beautemps
,
R.
Laboissière
 et al., “
Recovery of vocal-tract geometry from formants for vowels and fricative consonants using a midsaggital-to-area function conversion model
,”
J. Phonetics
23
,
221
229
(
1995
).
21.
D.
Beautemps
,
P.
Badin
, and
R.
Laboissière
, “
Deriving vocal-tract area functions from midsaggital profiles and formant frequencies: A new model for vowels and fricative consonants based on experimental data
,”
Speech Commun.
16
,
27
47
(
1995
).
22.
J.
Claerbout
,
Fundamentals of Geophysical Data Processing
(
McGraw-Hill
,
New York
,
1976
.
23.
Rakesh
, “
Impedance inversion from transmission data for the wave equation
,”
Wave Motion
24
,
263
274
(
1996
).
24.
Rakesh
and
P.
Sacks
, “
Characterisation of transmission data for Webster’s horn equation
,”
Inverse Probl.
16
,
L9
L24
(
2000
).
25.
N.
Amir
,
G.
Rosenhouse
, and
U.
Shimony
, “
A discrete model for tubular acoustic systems with varying cross-section—The direct and inverse problems. I II. Theory and experiment
,”
Acustica
81
,
450
474
(
1995
).
26.
J.
Agulló
and
S.
Cardona
, “
Time-domain deconvolution to measure reflection functions for discontinuities in waveguides
,”
J. Acoust. Soc. Am.
97
,
1950
1957
(
1995
).
27.
D. H.
Keefe
, “
Acoustical wave propagation in cylindrical ducts: Transmission line parameter approximations for isothermal and nonisothermal boundary conditions
,”
J. Acoust. Soc. Am.
75
,
58
62
(
1984
).
28.
J. G.
Berryman
and
R. R.
Greene
, “
Discrete inverse methods for elastic waves in layered media
,”
Geophysics
45
,
213
233
(
1980
).
29.
V.
Pagneux
,
N.
Amir
, and
J.
Kergomard
, “
A study of wave propagation in varying cross-section waveguides by modal decomposition. I. Theory and validation
,”
J. Acoust. Soc. Am.
100
,
2034
2048
(
1996
).
30.
C.
Hazard
and
V.
Pagneux
, “
Improved multimodal approach in waveguides with varying cross-section
,”
Proceedings of the 17th International Congress on Acoustics
,
Rome
,
2001
, Vol. 25, No.
1–3
, pp.
3
,
4
.
31.
J. A.
Kemp
, “
Multimodal propagation in acoustic horns
,”
Proceedings of the International Symposium on Musical Acoustics
,
Perugia, Italy
,
2001
, Vol. 2, pp.
521
524
.
32.
J. A.
Kemp
, “
Theoretical and experimental study of wave propagation in brass musical instruments
,” Ph.D. thesis,
University of Edinburgh
,
2002
.
33.
A. M.
Bruneau
,
M.
Bruneau
,
P. H.
Herzog
, and
J.
Kergomard
, “
Boundary layer attenuation of higher order modes in waveguides
,”
J. Sound Vib.
119
,
15
27
(
1987
).
34.
A. H.
Benade
and
E. V.
Jansson
, “
On plane and spherical waves with nonuniform flare. I. Theory of radiation, resonance frequencies and mode conversion
,”
Acustica
31
,
79
98
(
1974
).
35.
B. J.
Forbes
, “
A potential-function analysis of speech acoustics
,” Ph.D. thesis, Department of Physics,
King’s College London
, Strand, London WC2R 2LS,
2000
.
36.
B. J.
Forbes
,
E. R.
Pike
, and
D. B.
Sharp
, “
The acoustical Klein-Gordon equation: The wave-mechanical step and barrier functions
,”
J. Acoust. Soc. Am.
114
,
1291
1302
(
2003
).
37.
B. J.
Forbes
and
E. R.
Pike
, “
The acoustical Klein-Gordon equation: A time-independent perturbation analysis
,”
Phys. Rev. Lett.
93
,
1
4
(
2004
).
38.
B. J.
Forbes
, “
The acoustical impedance defined by ‘wave function’ solutions of the reduced Webster equation
,”
Phys. Rev. E
72
(
1
),
1
4
(
2005
).
39.
S.
Gasiorowicz
,
Quantum Physics
(
Wiley
,
New York
,
1974
) pp.
469
471
.
40.
K.
Chadan
and
P. C.
Sabatier
,
Inverse Problems in Quantum Scattering Theory
, 2nd ed., (
Springer
,
New York
,
1989
), Chap. XVII.
41.
Rakesh
, “
Potential inversion from transmission data for the one-dimensional wave equation
,”
Wave Motion
25
,
319
329
(
1997
).
42.
T.
Aktosun
, “
Construction of the half line potential from the Jost function
,”
Inverse Probl.
20
,
859
876
(
2004
).
43.
N.
Amir
,
U.
Shimony
, and
G.
Rosenhouse
, “
Losses in tubular acoustic systems—Theory and experiment in the sampled time and frequency domains
,”
Acust. Acta Acust.
82
,
1
8
(
1996
).
44.
M. H. F.
de Salis
,
N. V.
Movchan
, and
D. J.
Oldham
, “
Characterising holes in duct walls using resonance frequencies
,”
J. Acoust. Soc. Am.
111
,
2583
2593
(
2002
).
45.
T.
Aktosun
, “
Inverse scattering for vowel articulation with frequency-domain data
,”
Inverse Probl.
21
,
899
914
(
2005
).
46.
A.
Kounoudes
,
P. A.
Naylor
, and
M.
Brookes
, “
The DYPSA algorithm for estimation of glottal closure instants in voiced speech
,”
Proc. ICASSP
,
2002
.
47.
J.
Epps
,
J. R.
Smith
, and
J.
Wolfe
, “
A novel instrument to measure acoustic resonances of the vocal tract during phonation
,”
Meas. Sci. Technol.
8
,
1112
1121
(
1997
).
You do not currently have access to this content.