CN108872390A - A kind of supersonic guide-wave composite imaging method based on instantaneous phase - Google Patents
A kind of supersonic guide-wave composite imaging method based on instantaneous phase Download PDFInfo
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- CN108872390A CN108872390A CN201810838804.7A CN201810838804A CN108872390A CN 108872390 A CN108872390 A CN 108872390A CN 201810838804 A CN201810838804 A CN 201810838804A CN 108872390 A CN108872390 A CN 108872390A
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- imaging
- defect
- instantaneous phase
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/04—Analysing solids
- G01N29/06—Visualisation of the interior, e.g. acoustic microscopy
- G01N29/0654—Imaging
- G01N29/069—Defect imaging, localisation and sizing using, e.g. time of flight diffraction [TOFD], synthetic aperture focusing technique [SAFT], Amplituden-Laufzeit-Ortskurven [ALOK] technique
Abstract
The invention discloses a kind of supersonic guide-wave composite imaging method based on instantaneous phase, belongs to ultrasonic technique field.The principle of complex imaging is acquired respectively by array energy transducerMode andThe time-domain signal of mode guided wave carries out Hilbert transform to two kinds of signals and obtains instantaneous phase；Instantaneous phase image is obtained using amplitude and instantaneous phase information according to total focus imaging method；One threshold value is set to each imaging point for phase information, according to the decision principle pair setMode andThe instantaneous phase image of mode carries out complex imaging.The present invention can detect the small defect in plated metal structure well, and defect is visualized, and the profession for reducing operator requires, and the contrast of imaging can be improved using the method, reduce the omission factor of defect.
Description
Technical field
The present invention relates to a kind of supersonic guide-wave composite imaging method based on instantaneous phase, and in particular to multi-modal to be combined into
Picture and the imaging of vector total focus, belong to field of non destructive testing.
Technical background
Metal plate structure is a kind of common structure type in industrial equipment, is widely used in aerospace, ship, machinery
The industrial circles such as manufacture, therefore seem most important to the detection of plate structure.Compared with traditional detection mode, supersonic guide-wave
Detection has small, the distance of propagation of decaying when propagating, and detection efficiency is high, the big feature of detection range, by guided wave signals
Imaging technique research, visualization and the resolution of defect type can be improved, reduce the operation difficulty of technical staff.
There is the symmetrical mode (S) based on in-plane displacement and the antisymmetry mode based on acoplanarity displacement in plate structure
(A), wherein antisymmetry mode is more sensitive for surface defect type, and symmetrically mode is in thickness direction to defect recognition ability
It is more average, therefore by the complex imaging to both modalities which guided wave signals, it can more effectively identify more in plate structure
Kind defect.On this basis, by establishing the imaging of vector total focus, poroid defect and crack defect can be identified, and can be very well
Ground judges the direction of defect.
Summary of the invention
In view of the deficiencies of the prior art, the invention proposes a kind of supersonic guide-waves based on instantaneous phase to be combined into image space
Method realizes the visualization of defects detection, improves the detection efficiency of each defect type, and the direction for realizing crack defect is known
Not.
The present invention is achieved by the following technical solutions, and a kind of supersonic guide-wave based on instantaneous phase is combined into image space
Method includes the following steps：
（1）In such a way that complete matrix acquires, successively N number of array element of excitation linear array energy transducer, is connect by other N-1 array element
The collection of letters number, collects NN group complete matrix time-domain signal, wherein i represents excitation array element, and j, which is represented, receives array element；
（2）Time-domain signal is configured to analytical function, obtain the instantaneous phase of signal, formula
It is as follows：
WhereinFor original signal,For the Hilbert transform of original signal；
（3）Imaging coordinate system is established, using array energy transducer center as coordinate origin, x indicates energy converter horizontal direction, and z expression is changed
It can device vertical direction.For each imaging point, amplitude information is
Its phase information is
WhereinPass through imaging point from transmitting array element for signalTo the flight time for receiving array element；
（4）Set the threshold value of instantaneous phase, to reduce error caused by noise signal, the phase of noise signal is divided at random
Cloth, phase standard are poor, for the imaging point P (x, z) of defect is not present, will lead to by noise signal and be mistaken for depositing
In defect；According to Chebyshev inequality
WhereinIt is the probability of error indication defect, thus obtains threshold valueFormula it is as follows：
Wherein M is signal number, i.e.,；
（5）It determining instantaneous phase weighted factor IPWF, is more than the imaging point of threshold value for phase information, IPWF value is 1, for
Phase information is more than the point of threshold value, IPWF value, tiny flaw quilt can be prevented while improving picture contrast with this
The expression formula of missing inspection, IPWF is as follows：
（6）Instantaneous phase weighted imaging, by following formula
It obtainsWithTwo width instantaneous phase weighted images；
（7）According to what is obtainedMode andMode instantaneous phase weighted image, according to following regular complex imaging
It is directed to each imaging point, if two modeAll it is higher than their own threshold value, then means both modalities which all
Detect defect, combination pictureTake the larger value of the two；If two modeBelow their own threshold value, then anticipate
Taste both modalities which defect, combination picture is all not detectedTake the smaller value of the two；If only one of modeIt is super
Threshold value is crossed, then means the Modal detection to defect, combination pictureTake the value of the mode；
（8）Local Vector imaging is carried out to defect part to include the following steps,
Firstly, by complex imaging figureIn at each defect maximum value region corresponding to decline -6dB carry out Local Vector and gather entirely
Coke imaging, the unit direction vector of each imaging point P (x, z) are
Wherein, it is normal direction Unit Vector of the guided wave signals by the plane of reflection at imaging point
Amount.
Secondly, unit direction vector is multiplied with imaging point amplitude can be obtained amplitude vector, following formula can be passed through
It calculates
Finally, the relationship vertical with target defect reflecting surface according to amplitude direction vector, can calculate target defect and x-axis is positive
Corner dimension, calculated by following formula
Wherein A represents the range of defect in imaging region,Indicate the x-component of amplitude vector,Indicate amplitude
The z-component of vector.
The beneficial effects of the invention are as follows：The guided wave signals of both modalities which are subjected to complex imaging, and defect part is carried out
Local Vector imaging, can effectively detect different types of defect, judge the angle of defect to identify that poroid defect and crackle lack
It falls into；The contrast that can effectively improve image by instantaneous phase weighting, reduces the generation of pseudomorphism, for detecting metal plate-like knot
Structure has actual engineering application value.
Detailed description of the invention
Fig. 1 is that flow chart of the method for the present invention is also summary diagram of the invention；
Fig. 2 is the imaging coordinate system that the present invention is implemented.
Specific embodiment
Invention is further described in detail in the following with reference to the drawings and specific embodiments.
As shown in Figure 1, the present invention provides a kind of supersonic guide-wave composite imaging method based on instantaneous phase, is effectively detected
The defects of metal plate-like structure, this method comprises the following steps：
（1）In such a way that complete matrix acquires, successively N number of array element of excitation linear array energy transducer, is connect by other N-1 array element
The collection of letters number, collects NN group complete matrix time-domain signal, wherein i represents excitation array element, and j, which is represented, receives array element；
（2）Time-domain signal is configured to analytical function, obtain the instantaneous phase of signal, formula
It is as follows：
WhereinFor original signal,For the Hilbert transform of original signal；
（3）Imaging coordinate system is established, using array energy transducer center as coordinate origin, x indicates energy converter horizontal direction, and z expression is changed
It can device vertical direction.For each imaging point, amplitude information is
Its phase information is
WhereinPass through imaging point from transmitting array element for signalTo the flight time for receiving array element；
（4）Set the threshold value of instantaneous phase, to reduce error caused by noise signal, the phase of noise signal is divided at random
Cloth, phase standard are poor, for the imaging point P (x, z) of defect is not present, will lead to by noise signal and be mistaken for depositing
In defect.According to Chebyshev inequality
WhereinIt is the probability of error indication defect, thus obtains threshold valueFormula it is as follows：
Wherein M is signal number, i.e.,；
（5）It determining instantaneous phase weighted factor IPWF, is more than the imaging point of threshold value for phase information, IPWF value is 1, for
Phase information is more than the point of threshold value, IPWF value, tiny flaw quilt can be prevented while improving picture contrast with this
The expression formula of missing inspection, IPWF is as follows：
（6）Instantaneous phase weighted imaging, by following formula
It obtainsWithTwo width instantaneous phase weighted images；
（7）According to what is obtainedMode andMode instantaneous phase weighted image, according to following regular complex imaging
It is directed to each imaging point, if two modeAll it is higher than their own threshold value, then means both modalities which all
Detect defect, combination pictureTake the larger value of the two；If two modeBelow their own threshold value, then anticipate
Taste both modalities which defect, combination picture is all not detectedTake the smaller value of the two；If only one of mode
More than threshold value, then mean the Modal detection to defect, combination pictureTake the value of the mode；
（8）Local Vector imaging is carried out to defect part
Firstly, by complex imaging figureIn at each defect maximum value region corresponding to decline -6dB carry out Local Vector and gather entirely
Coke imaging, the unit direction vector of each imaging point P (x, z) are
Wherein, it is normal direction Unit Vector of the guided wave signals by the plane of reflection at imaging point
Amount.
Secondly, unit direction vector is multiplied with imaging point amplitude can be obtained amplitude vector, following formula can be passed through
It calculates
Finally, the relationship vertical with target defect reflecting surface according to amplitude direction vector, can calculate target defect and x-axis is positive
Corner dimension, calculated by following formula
Wherein A represents the range of defect in imaging region,Indicate the x-component of amplitude vector,Indicate amplitude
The z-component of vector.
Above-described embodiment is used to illustrate the present invention, rather than limits the invention, in spirit of the invention and
In scope of protection of the claims, to any modifications and changes that the present invention makes, protection scope of the present invention is both fallen within.
Claims (1)
1. a kind of supersonic guide-wave composite imaging method based on instantaneous phase, which is characterized in that include the following steps：
（1）In such a way that complete matrix acquires, successively N number of array element of excitation linear array energy transducer, is connect by other N-1 array element
The collection of letters number, collects NN group complete matrix time-domain signal, wherein i represents excitation array element, and j, which is represented, receives array element；
（2）Time-domain signal is configured to analytical function, the instantaneous phase of signal is obtained, formula is such as
Under：
WhereinFor original signal,For the Hilbert transform of original signal；
（3）Imaging coordinate system is established, using array energy transducer center as coordinate origin, x indicates energy converter horizontal direction, and z expression is changed
It can device vertical direction；For each imaging point, amplitude information is
Its phase information is
WhereinPass through imaging point from transmitting array element for signalTo the flight time for receiving array element；
（4）Set the threshold value of instantaneous phase, to reduce error caused by noise signal, the phase random distribution of noise signal,
Its phase standard is poor, for the imaging point P (x, z) of defect is not present, will lead to by noise signal and be mistaken for existing
Defect；According to Chebyshev inequality
WhereinIt is the probability of error indication defect, thus obtains threshold valueFormula it is as follows：
Wherein M is signal number, i.e.,；
（5）It determining instantaneous phase weighted factor IPWF, is more than the imaging point of threshold value for phase information, IPWF value is 1, for
Phase information is more than the point of threshold value, IPWF value, tiny flaw quilt can be prevented while improving picture contrast with this
The expression formula of missing inspection, IPWF is as follows：
（6）Instantaneous phase weighted imaging, by following formula
It obtainsWithTwo width instantaneous phase weighted images；
（7）According to what is obtainedMode andMode instantaneous phase weighted image, according to following regular complex imaging
It is directed to each imaging point, if two modeAll it is higher than their own threshold value, then means that both modalities which is all examined
Measure defect, combination pictureTake the larger value of the two；If two modeBelow their own threshold value, then mean
Both modalities which defect, combination picture is all not detectedTake the smaller value of the two；If only one of modeIt is super
Threshold value is crossed, then means the Modal detection to defect, combination pictureTake the value of the mode；
（8）Local Vector imaging is carried out to defect part to include the following steps,
Firstly, by complex imaging figureIn at each defect maximum value region corresponding to decline -6dB carry out Local Vector and gather entirely
Coke imaging, the unit direction vector of each imaging point P (x, z) are
Wherein, it is normal direction unit vector of the guided wave signals by the plane of reflection at imaging point；
Secondly, unit direction vector is multiplied with imaging point amplitude can be obtained amplitude vector, can be calculate by the following formula
Finally, the relationship vertical with target defect reflecting surface according to amplitude direction vector, can calculate target defect and x-axis is positive
Corner dimension, calculated by following formula
Wherein A represents the range of defect in imaging region,Indicate the x-component of amplitude vector,Indicate amplitude
The z-component of vector.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110147781A (en) * | 2019-05-29 | 2019-08-20 | 重庆交通大学 | Bridge vibration mode based on machine learning visualizes damnification recognition method |
| CN117347502A (en) * | 2023-12-04 | 2024-01-05 | 中国飞机强度研究所 | Full-focusing imaging method and system for thin-wall blade |
-
2018
- 2018-07-27 CN CN201810838804.7A patent/CN108872390A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110147781A (en) * | 2019-05-29 | 2019-08-20 | 重庆交通大学 | Bridge vibration mode based on machine learning visualizes damnification recognition method |
| CN110147781B (en) * | 2019-05-29 | 2022-11-15 | 重庆交通大学 | Bridge vibration mode visual damage identification method based on machine learning |
| CN117347502A (en) * | 2023-12-04 | 2024-01-05 | 中国飞机强度研究所 | Full-focusing imaging method and system for thin-wall blade |
| CN117347502B (en) * | 2023-12-04 | 2024-03-12 | 中国飞机强度研究所 | Full-focusing imaging method and system for thin-wall blade |
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