Signal processing system and methods

Patent metadata

Field	Value
Publication number	US-10168302-B2
Application number	US-201415028661-A
Country	US
Kind code	B2
Filing date	Oct 13, 2014
Priority date	Oct 11, 2013
Publication date	Jan 1, 2019
Grant date	Jan 1, 2019

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

The invention claimed is:

1. 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 number of 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 one or both of an impulse response, h(t),of the pipe and a corresponding-transfer function of the pipe from the number of associated waveforms; the one or both of the impulse response and the transfer function bearing the characteristic acoustic impedance associated with the pipe, wherein the step of deriving the one or both of the impulse response and the transfer function 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.

2. The method of claim 1 , further comprising exciting the pipe using the excitation waveform via the launch body.

3. The method of claim 1 , 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.

4. The method of claim 1 , further comprising filtering the plurality of measured resultant pressure waveforms prior to said resolving.

5. The method of claim 4 , wherein the step of filtering applies one or more than one filter associated with a possible characteristic acoustic impedance.

6. The method of claim 1 , wherein the step of resolving the plurality of measured resultant pressure waveforms into the number of associated waveforms comprises resolving the plurality of measured resultant pressure waveforms into the number of associated waveforms representing differences between the measured resultant pressure waveforms.

7. The method of claim 6 , 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.

8. The method of claim 7 , 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.

9. The method of claim 1 , wherein the step of deriving the one or both of the impulse response and the transfer function comprises evaluating h(t) from h(t)*[p x1 (t)−p x2 (t−τ)]=[p x2 (t+τ)−p x1 (t)].

10. The method of claim 9 , wherein the step of deriving the one or both of the impulse response and the transfer function 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.

11. The method of claim 1 , wherein the step of deriving the one or both of the impulse response and the transfer function comprises evaluating

h
⁡

(
t
)

=

IFFT
⁡

[

Assignees

• Univ Manchester

Inventors

• Lennox Barry
• Groves Keir

Classifications

• G01M3/02

  by using fluid or vacuum · CPC title

• G01M3/243

  for pipes · CPC title

• G01N29/46

  by spectral analysis, e.g. Fourier analysis {or wavelet analysis (spectral signal processing per se G06F17/14)} · CPC title

• G01N2291/2636

  cylindrical from inside · CPC title

• G01N2291/0289

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