Signal Processing System and Methods

Patent metadata

Field	Value
Publication number	US-2016258906-A1
Application number	US-201415028661-A
Country	US
Kind code	A1
Filing date	Oct 13, 2014
Priority date	Oct 11, 2013
Publication date	Sep 8, 2016
Grant date	—

Abstract

Embodiments relate to a signal processing system and method in particular for determining the location of a feature within a hollow body using deconvolution of measured acoustic waves.

First claim

1 - 38 . (canceled)

39 . A pipe inspection method to identify characteristic acoustic impedance associated with a pipe; the method comprising the steps of
resolving a plurality of measured resultant pressure waveforms, p x1 (t), p x2 (t) . . . , p xn (t) and p x2 (t), associated with the pipe into a number of associated waveforms; the associated waveforms being a function of the plurality of measured resultant pressure waveforms measured at respective positions; the plurality of measured resultant pressure waveforms representing measurements by a plurality of acoustic detection devices positioned at the respective positions of a launch body for exciting the pipe using an excitation waveform; deriving the impulse response, h(t), or transfer function of the pipe from said at least a pair associated waveforms; the impulse response bearing the characteristic acoustic impedance associated with the pipe, wherein the step of deriving the impulse response comprises evaluating h(t) from h(t)*[p x1 (t)−p x2 (t)*h m12 (t)]=[p x2 (t)*h m12 −1 (t)−p x1 (t)], where h m12 (t) represents the transfer function between a first and second acoustic detection devices of the plurality of acoustic detection devices.

40 . The method of claim 39 , further comprising exciting the pipe using the excitation waveform via the launch body.

41 . The method of claim 39 , further comprising taking a plurality of measurements via the acoustic detection devices; the plurality of measured resultant pressure waveforms being associated with the plurality of measurements.

42 . The method of claim 39 , further comprising filtering the plurality of measured resultant pressure waveforms prior to said resolving.

43 . The method of claim 42 , wherein the step of filtering applies one or more than one filter associated with a possible characteristic acoustic impedance.

44 . The method of claim 39 , wherein the step of resolving the plurality of measured resultant pressure waveforms into a number of associated waveforms comprises resolving the plurality of measured resultant pressure waveforms into a number of associated waveforms representing differences between the measured resultant pressure waveforms.

45 . The method of claim 44 , wherein the differences between the measured resultant pressure waveforms have an associated linear function or represent time shifted versions of the measured resultant pressure waveforms.

46 . The method of claim 45 , wherein the linear function or differences take the form
f ( p ( t ))= p ( t +τ)− p ( t −τ)
where p(t) represents a measured resultant pressure waveform at time t; and τ is associated with the separation between acoustic measuring devices.

47 . The method of claim 39 , wherein the step of deriving the impulse response comprises evaluating h(t) from h(t)*[p x1 (t)−p x2 (t−τ)]−[p x2 (t+τ)−p x1 (t)].

48 . The method of claim 47 , wherein the step of deriving the impulse response comprises evaluating

h


(
t
)

=

IFFT


{

FFT


[

p

x



2



(

t
+
τ

)

-

p

x



1



(
t
)

]

FFT


[

p

x



1



(
t
)

-

p

x



2



(

t
-
τ

)

]

}

where FFT represents a Fourier Domain Transform and IFFT represents an Inverse Fourier Domain Transform.

49 . The method of claim 39 , wherein the step of deriving the impulse response comprises evaluating

h


(
t
)

=

IFFT


[

FFT


[

Assignees

• Univ Manchester

Inventors

• Lennox Barry
• Groves Keir

Classifications

• G01M3/243

  for pipes · CPC title

• G01N2291/2636

  cylindrical from inside · CPC title

• G01M3/02

  by using fluid or vacuum · CPC title

• G01N2291/0289

  Internal structure, e.g. defects, grain size, texture · CPC title

• G01N29/09 Primary

  by measuring mechanical or acoustic impedance · CPC title