Defect detection method and system using high frequency waves
AssigneeThe Hong Kong University of Science and Technology
InventorsGeorgios Grigoropoulos, Saber Nasraoui, Moez Louati, Mohamed Salah Ghidaoui
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Abstract
A defect detection method is provided for a pressurized pipe having at least one defect. According to the method, an acoustic source generates a probing wave of a frequency range from 10 kHz to 100 kHz, where the probing wave is scattered by the at least one defect to create a reflected wave; an acoustic receiver measures a wave response to obtain a measured response, where the measured response is attributed essentially to a superposition of the probing wave and the reflected wave; and a computer device processes the measured response to locate the at least one defect.
Claims19
A method of defect detection for a pressurized pipe having at least one defect, the method comprising:
- generating, by an acoustic source located at xs, a probing wave of a frequency range from 10 kHz to 100 kHz, the probing wave being scattered by the at least one defect to create a reflected wave;
- measuring, by an acoustic receiver located at xm, a wave response to obtain a measured response, the measured response being attributed essentially to a superposition of the probing wave and the reflected wave;
- and
- processing, by a computer device, the measured response to locate the at least one defect,
- wherein processing the measured response comprises:
- determining a defect-related response Δ{circumflex over (p)} from the measured response, the defect-related response Δ{circumflex over (p)} being attributed essentially to the at least one defect and expressed in frequency domain;
- and
- computing an objective function A(xd) by performing a convolution operation between an analytical response g(ω) and Δ{circumflex over (p)}* such that A(xd)=|g(xd, ω)Δ{circumflex over (p)}*(w)|2, where |·|2 denotes an Euclidian norm, * denotes a phase conjugation operation, Δ{circumflex over (p)}* is phase conjugation of Δ{circumflex over (p)}, xd refers to potential defect location, and ω is a angular frequency vector.
A system of defect detection for a pressurized pipe having at least one defect, the system comprising:
- an acoustic source located at xs along the pressurized pipe for generating a probing wave of a frequency range from 10 kHz to 100 kHz;
- an acoustic receiver located at xm for obtaining a measured response that comprises a superposition of the probing wave and a reflected wave, the reflected wave being generated by scattering of the probing wave by the at least one defect;
- and
- a computer device for processing the measured response to locate the at least one defect, wherein the computer device is configured to:
- determine a defect-related response Δ{circumflex over (p)} from the measured response, the defect-related response Δ{circumflex over (p)} being attributed essentially to the at least one defect and expressed in frequency domain;
- and
- compute an objective function A(xd) by performing a convolution operation between an analytical response g(ω) and Δ{circumflex over (p)}* such that A(xd)=|g(xd, ω)Δ{circumflex over (p)}*(ω)|2, where |·|2 denotes an Euclidian norm, * denotes a phase conjugation operation, Δ{circumflex over (p)}* is phase conjugation of Δ{circumflex over (p)}, xd refers to potential defect location, and ω is a angular frequency vector.
A method of defect detection for a pressurized pipe having at least one defect, the method comprising:
- receiving a measured response from an acoustic receiver, wherein the measured response comprises a superposition of a probing wave and a reflected wave, the probing wave being generated by an acoustic source and having a frequency range from 10 kHz to 100 kHz, the reflected wave being generated by scattering of the probing wave by the at least one defect;
- sampling the measured response at a sampling frequency that is at least ten times of a maximum frequency in the frequency range;
- determining a defect-related response Δ{circumflex over (p)} from the measured response, the defect-related response Δ{circumflex over (p)} being attributed to the at least one defect and expressed in frequency domain;
- computing a conjugation operation of the defect-related response Δ{circumflex over (p)} to obtain Δ{circumflex over (p)}*;
- computing an objective function by performing a convolution operation between a pre-determined analytical response and Δ{circumflex over (p)}*;
- and
- determining defect location for the at least one defect by identifying maximum of the objective function.
Dependencies are inferred from the claim text.