Intensity-controllable ultrasonic envelope segmentation extraction method

Abstract

The present invention discloses an intensity-controllable ultrasonic envelope segmentation extraction method, comprising the following steps: step 1: an ultrasonic device obtains an A-scan signal #imgabs0# from a probe; step 2: an envelope signal #imgabs2# of the A-scan signal #imgabs1# is obtained by using a Hilbert transform; step 3: the A-scan signal #imgabs3# is aligned with the envelope signal #imgabs4#, and then an absolute value is taken to obtain a signal #imgabs5#; step 4: envelope weights #imgabs6#, #imgabs7#, and #imgabs8# are set to integers greater than or equal to 1; the envelope weight #imgabs9# is segmented and set according to an ultrasonic scanning time axis to control envelope signals of different segments; the envelope signal #imgabs10# and the signal #imgabs11# are respectively multiplied by the envelope weights #imgabs12# and #imgabs13#, and then the sum is added, and the resultant signal is shifted right by #imgabs14# positions to obtain ultrasonic segmented weighted envelope signals. The ultrasonic envelope segmented extraction method with controllable intensity solves the problem that different intensities cannot be used in different segments during the existing ultrasonic envelope extraction.

Description

Technical Field

[0001] The invention belongs to the technical field of ultrasonic non-destructive testing, and specifically relates to an intensity-controllable ultrasonic envelope segmentation extraction method. Background Art

[0002] In the field of industrial ultrasonic testing, video filtering is often used to extract the envelope of the ultrasonic A-scan to better visualize and analyze defects, making the defect signal smoother and closer to reality. Currently, the Hilbert transform method is mostly used to extract the ultrasonic signal envelope. When enabled, this method extracts the envelope of the entire ultrasonic A-scan signal, but the strength of the extracted envelope cannot be adjusted, which can be inconvenient to use. If the defect signal is very close to the interface, such as defects near the surface, near the bottom, or near the junction of two materials, when video filtering is enabled and the envelope is extracted, the defect signal may merge with the interface wave signal, making the defect signal unobservable. In this case, although these defect signals can be viewed without video filtering, if the workpiece being inspected also has defects in other locations not close to the interface, the defect signals in these other locations will be less visually appealing due to the lack of video filtering. In particular, during the automated scanning process, the ultrasonic scanning image is often required to be more complete. In order to simultaneously observe the defect signal at the interface position and the defect signal at other positions, the video filter intensity at the interface position needs to be different from the video filter intensity at other positions. Summary of the Invention

[0003] In view of this, the object of the present invention is to provide a method for ultrasonic envelope segmentation extraction with controllable intensity, so as to solve the deficiency that different intensities cannot be used in different segments during the existing ultrasonic envelope extraction.

[0004] In order to achieve the above object, the present invention provides the following technical solutions:

[0005] A method for extracting ultrasonic envelope segments with controllable intensity comprises the following steps:

[0006] Step 1: The ultrasound device obtains the A-scan signal from the probe ;

[0007] Step 2: Obtain A-scan signal using Hilbert transform The envelope signal ;

[0008] Step 3: Scan the A signal With envelope signal After alignment, take the absolute value to get the signal ;

[0009] Step 4: Set the envelope weight , , is an integer greater than or equal to 1; the envelope weight is set according to the ultrasound scanning time axis Make segment settings to control the envelope signal of different segments;

[0010] The envelope signal and signal Envelope weight and Multiply, add, and shift right The ultrasonic segment weighted envelope signal is obtained.

[0011] Furthermore, in step 2, the envelope signal for:

[0012]

[0013] in: Analyze the imaginary part of the signal for the Hilbert transform; is the real part of the Hilbert analytic signal.

[0014] Furthermore, the Hilbert transform analyzes the imaginary part of the signal The output is from an FIR filter, which is designed as an all-pass filter with a passband gain of 1, a phase characteristic of a positive frequency phase shift of -90°, a negative frequency phase shift of 90°, and an even order.

[0015] Furthermore, Hilbert analytic signal real part By scanning the A signal Phase compensation is obtained by delay, and the delay time is is each clock cycle, and:

[0016]

[0017] in: The order of the FIR filter design; Fixed delay introduced by register logic when designing for FIR filters.

[0018] The beneficial effects of the present invention are:

[0019] The intensity-controllable ultrasonic envelope segmentation extraction method of the present invention obtains the A-scan signal by adopting Hilbert transform The envelope signal Then, scan the A signal Through the delay and envelope signal Align and take the absolute value to get the signal ; In this way, the envelope signal can be and signal Perform segmented weight superposition and transform the envelope signal The envelope weight is set to , the signal The envelope weight is set to , so the superimposed signal is shifted right The ultrasonic weighted envelope signal is obtained, which solves the problem that different intensities cannot be used in different segments when extracting the ultrasonic envelope. It has the following advantages:

[0020] (1) The video filter intensity of ultrasonic detection is adjustable, and the A-scan signal envelope of different intensities can be obtained;

[0021] (2) Envelope weighting based on ultrasound scanning time axis Segment settings are performed to control the envelope signals of different segments. In this way, envelopes of different intensities can be set for the same A-scan signal segment, which can obtain a more satisfactory envelope signal and meet the requirements of simultaneously observing the defect signal at the interface position and the defect signal at other positions. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to make the purpose, technical solutions and beneficial effects of the present invention more clear, the present invention provides the following drawings for illustration:

[0023] Figure 1 Flowchart of an embodiment of the ultrasonic envelope segmentation extraction method with controllable intensity according to the present invention;

[0024] Figure 2 To obtain the envelope signal through FPGA Schematic diagram;

[0025] Figure 3 This is the schematic diagram of the segmented weight superposition module;

[0026] Figure 4 To set the envelope strength Set as a schematic diagram of three segments;

[0027] Figure 5 is the envelope signal of the ultrasonic segment weighted. DETAILED DESCRIPTION

[0028] The present invention will be further described below with reference to the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it. However, the embodiments are not intended to limit the present invention.

[0029] like Figure 1 As shown, the intensity-controllable ultrasonic envelope segmentation extraction method of this embodiment includes the following steps.

[0030] Step 1: The ultrasound device obtains the A-scan signal from the probe .

[0031] Step 2: Obtain A-scan signal using Hilbert transform The envelope signal .

[0032] Specifically, the time domain conversion formula of Hilbert transform is:

[0033]

[0034] in: represents the Hilbert transform.

[0035] From a spectral perspective, the Hilbert transform multiplies the positive frequency portion of the original signal by -j and the negative frequency portion by j. This means that while keeping the amplitude unchanged, the positive frequency is phase-shifted by -90°, while the negative frequency component is phase-shifted by 90°.

[0036] like Figure 2 As shown, this embodiment takes FPGA as an example, and the Hilbert transform module in FPGA is implemented by FIR filter. In this embodiment, the FIR filter is designed as an all-pass filter with a passband gain of 1, a phase characteristic of -90° phase shift at positive frequency and 90° phase shift at negative frequency, and an even order. The signal output by the FIR filter It is the imaginary part of the Hilbert transform analytic signal. Since the FIR filter has a fixed delay, the original A-scan signal needs to be Perform phase compensation to obtain the real part of the Hilbert analytical signal. Phase compensation is achieved through delay, and the delay time is is each clock cycle, and:

[0037]

[0038] in: The order of the FIR filter design; Fixed delay introduced by register logic when designing for FIR filters.

[0039] Signal after phase compensation and the signal after Hilbert transform At the same time, the envelope extraction module is entered. The envelope extraction module calculates the module of the Hilbert analytical signal and obtains the envelope of the original A-scan signal. The envelope signal for:

[0040]

[0041] in: Analyze the imaginary part of the signal for the Hilbert transform; is the real part of the Hilbert analytic signal.

[0042] In FPGA, squaring is implemented by multipliers and square root is implemented by CORDIC algorithm.

[0043] Step 3: Scan the A signal With envelope signal After alignment, take the absolute value to get the signal .

[0044] Specifically, in this embodiment, by After delay, the envelope signal is obtained Align and take the absolute value to get the signal .

[0045] Step 4: Set the envelope weight , , is an integer greater than or equal to 1; the envelope weight is set according to the ultrasound scanning time axis Make segment settings to control the envelope signal of different segments. and signal Envelope weight and Multiply, add, and shift right The ultrasonic segment weighted envelope signal is obtained.

[0046] Specifically, in this embodiment, the two signals and At the same time, it is input into the segment weight superposition module. The internal structure of the segment weight superposition module is as follows: Figure 3 As shown, The envelope weight is set. In order to facilitate the division operation by shifting in FPGA, the value of this embodiment is set to , The larger the value, the greater the envelope strength. .

[0047] Module pair Signal multiplied by Weight, yes Signal multiplied by The weights of the multiplied signals are added and right-shifted by 8 bits to obtain the weighted superposition signal.

[0048] in addition, It can be set in segments along the time axis of the A-scan signal, for example Figure 4 As shown in the figure, three segments are set. Assuming the sampling rate is 10ns and the sampling length is 160us, it is divided into 、 and There are three segments in total, and the weights of the three segments are set as: =0, =256 and = 100. FPGA switches different weights in different time periods to achieve segmented setting of different envelope intensities. Figure 5 For press Figure 4 Set the segmented extraction envelope effect.

[0049] The above embodiments are merely preferred embodiments for the purpose of fully illustrating the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are within the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

Claims

1. A method for extracting ultrasonic envelope segments with controllable intensity, characterized by: The steps include: Step 1: The ultrasound device obtains the A-scan signal from the probe ; Step 2: Obtain A-scan signal using Hilbert transform The envelope signal ; Step 3: Scan the A signal With envelope signal After alignment, take the absolute value to get the signal ; Step 4: Set the envelope weight , , is an integer greater than or equal to 1; the envelope weight is set according to the ultrasound scanning time axis Make segment settings to control the envelope signal of different segments; The envelope signal With envelope weight Multiply the signal With envelope weight Multiply, add the multiplied signals and shift them right The ultrasonic segment weighted envelope signal is obtained.

2. The method for extracting ultrasonic envelope segments with controllable intensity according to claim 1, wherein: In the step 2, the envelope signal for: in: Analyze the imaginary part of the signal for the Hilbert transform; is the real part of the Hilbert analytic signal.

3. The method for extracting ultrasonic envelope segments with controllable intensity according to claim 2, wherein: Hilbert transform of the imaginary part of an analytical signal The output is from an FIR filter, which is designed as an all-pass filter with a passband gain of 1, a phase characteristic of a positive frequency phase shift of -90°, a negative frequency phase shift of 90°, and an even order.

4. The method for extracting ultrasonic envelope segments with controllable intensity according to claim 3, wherein: Real part of Hilbert analytic signal By scanning the A signal Phase compensation is obtained by delay, and the delay time is is each clock cycle, and: in: The order of the FIR filter design; Fixed delay introduced by register logic when designing for FIR filters.

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