A fast imaging method of ultrasonic phased array phase shift for multilayer media

Abstract

The present invention discloses an ultrasonic phased array phase shift rapid imaging method for multi-layer media, comprising the following steps: obtaining Nt×N×N first receiving full matrix data obtained by sequentially transmitting ultrasonic waves through an ultrasonic probe through a test block, obtaining the thickness of each layer of media in the test block, and creating corresponding medium serial numbers from the surface medium to the bottom layer based on the distribution of each layer of media; creating Nt×N×N first transmitting full matrix data corresponding to the first receiving full matrix data; performing a two-dimensional fast Fourier transform, Stolt interpolation, and a two-dimensional fast inverse Fourier transform on the first receiving full matrix data and the first transmitting full matrix data to obtain image data of the corresponding layer of media, and recording the medium serial numbers of the corresponding layer of media; and when the generated medium serial numbers all match the recorded medium serial numbers, arranging the image data of each layer of media according to the order of the medium serial numbers to obtain a reconstructed test block image. The present invention aims to improve the efficiency of ultrasonic testing and imaging of multi-layer media.

Description

Technical Field

[0001] The present invention relates to the field of ultrasonic image reconstruction, and in particular to an ultrasonic phased array phase shift rapid imaging method for multi-layer media. Background Art

[0002] The existing traditional ultrasonic imaging detection of laminated structures is based on the Full Matrix Capture-Total Focus Method (FMC-TFM) with time domain post-processing. Drinkwater et al. applied FMC-TFM based on the Snell-Snell law to the laminated structure of wedges and test pieces, and successfully inspected the links of the Clifton Suspension Bridge. This method is also called ray-based total focusing technology (ray-based TFM). When the ray-tracing-based total focusing technology is applied to laminated structures, it is necessary to accurately calculate the refraction point of the ultrasonic sound path to obtain the delay time. The process is computationally intensive, resulting in long calculation time and low imaging efficiency. In terms of imaging technology for laminated structures, the frequency domain post-processing technology is mainly derived from the offset imaging technology of seismology and radar. The offset imaging technology algorithm is directly derived from the wave equation to obtain an accurate solution to the sound field. According to the explosion reflection model, the defect is regarded as an ultrasonic sound source. By performing a two-dimensional Fourier transform on the signal array obtained by the probe and recursively performing layer-by-layer recursion through the Phase Shift Migration (PSM) algorithm, high-resolution imaging of the entire detection area is performed.

[0003] The invention with the existing publication number CN10260820A proposes an ultrasonic imaging method for nondestructive testing of multi-layer dielectric stack structures based on variable wavenumber phase shift. This method performs frequency domain post-processing on the acquired data and uses phase shift technology to expand the sound field to each layer of the medium for imaging. Compared with ray tracing technology, this method improves the imaging speed. However, this method is only applicable to A-wave data acquired by a single probe and is not applicable to full matrix data acquired by an array probe, which results in limited imaging resolution of this method. In addition, the invention with application publication number CN113552219A discloses an ultrasonic self-focusing detection method for hole defects in stacked structures. Compared with the invention with publication number CN10260820A, this method enhances the final imaging effect and improves the image resolution by performing frequency domain post-processing on the full matrix data acquired by the array probe. However, the imaging processing calculation time of this method is long. Therefore, it is urgently needed to propose a new imaging processing method to improve the efficiency and imaging resolution of ultrasonic imaging. Summary of the Invention

[0004] The main purpose of the present invention is to provide an ultrasonic phased array phase shift rapid imaging method for multilayer media, aiming to solve the technical problem of low efficiency of ultrasonic detection imaging inside existing stacked structures.

[0005] To achieve the above object, the present invention provides a method for rapid phase shift imaging of multilayer media using an ultrasonic phased array, the method comprising the following steps:

[0006] Obtain the Nt×N×N first receiving full matrix data P obtained by the test block transmitting ultrasonic waves in sequence through the ultrasonic probe r , wherein the ultrasonic probe has N array elements, Nt is the sampling length, and the test block is a laminated structure containing multiple layers of dielectrics;

[0007] Obtain the thickness of each layer of medium in the test block, and create corresponding medium serial numbers from the surface medium to the bottom medium according to the distribution of each layer of medium;

[0008] Create and first receive full matrix data P r The corresponding Nt×N×N first emission full matrix data P t ;

[0009] The first received full matrix data P r , first transmit full matrix data P t Obtaining image data of the medium of the corresponding layer according to two-dimensional fast Fourier transform, Stolt interpolation processing and two-dimensional fast inverse Fourier transform, and recording the medium serial number of the medium of the corresponding layer;

[0010] When the created medium serial numbers all match the recorded medium serial numbers one by one, the image data of each layer of media are arranged in the order of the medium serial numbers to obtain a reconstructed test block image.

[0011] Optionally, the first received full matrix data P r , first transmit full matrix data P t The step of obtaining image data of the medium of the corresponding layer according to two-dimensional fast Fourier transform, Stolt interpolation processing and two-dimensional fast inverse Fourier transform includes:

[0012] The first received full matrix data P r , first transmit full matrix data P t The image data of the corresponding layers of media are obtained from the surface layer of media to the bottom layer of media according to two-dimensional fast Fourier transform, Stolt interpolation processing and two-dimensional fast inverse Fourier transform, and the media serial number of the corresponding layer of media is recorded;

[0013] When the recorded medium serial number is the bottom layer medium serial number, the image data of each layer of media are arranged in the order of the medium serial numbers to obtain a reconstructed test block image.

[0014] Optionally, the first received full matrix data P r , first transmit full matrix data P tThe step of obtaining image data of the medium of the corresponding layer according to two-dimensional fast Fourier transform, Stolt interpolation processing and two-dimensional fast inverse Fourier transform also includes:

[0015] The first received full matrix data P r , first transmit full matrix data P t Perform a two-dimensional fast Fourier transform to obtain the corresponding second receiving full matrix data P r2 , the second transmission full matrix data P t2 .

[0016] Optionally, the first received full matrix data P r , first transmit full matrix data P t The step of obtaining image data of the medium of the corresponding layer according to two-dimensional fast Fourier transform, Stolt interpolation processing and two-dimensional fast inverse Fourier transform also includes:

[0017] According to the current medium sound velocity and the current medium thickness, each second received full matrix data P r2 , the second transmission full matrix data P t2 The phase migration extends to the current medium surface layer, and the third receiving full matrix data P is obtained. r3 , the third emission full matrix data P t3 , the specific formula is as follows:

[0018]

[0019]

[0020]

[0021] Wherein, j is the transmitting array element number; j = 1, 2, 3, ... N; The total number of medium layers is L, the current medium number is M, and M is 1, 2, 3, ..., L; d M-1 is the thickness of the M-1th layer of medium, d0=0; k x is the horizontal wave number; z M is the depth information of the starting depth of recording from the surface of the M-th layer of medium; ω is the angular frequency.

[0022] Optionally, the third received full matrix data P is obtained r3 , the third emission full matrix data P t3 After the steps, it also includes:

[0023] Each third received full matrix data P r3 , the third emission full matrix data P t3 Perform stolt interpolation processing to obtain the corresponding fourth received full matrix data P r4, the fourth emission full matrix data P t4 , the specific formula is as follows:

[0024]

[0025]

[0026] in,

[0027] Optionally, the corresponding fourth received full matrix data P is obtained r4 , the fourth emission full matrix data P t4 After the steps, it also includes:

[0028] Each fourth received full matrix data P r4 , the fourth emission full matrix data P t4 Perform a two-dimensional fast inverse Fourier transform and superimpose the transmit array elements to obtain the image data of the corresponding layer of the medium. The specific formula is as follows:

[0029] Optionally, the first receiving full matrix data P is obtained by sequentially transmitting ultrasonic waves through the ultrasonic probe to obtain the Nt×N×N first receiving full matrix data P r The steps include:

[0030] Controlling the N array elements in the ultrasonic probe to sequentially transmit ultrasonic waves of a predetermined frequency to the test block and successively receiving the feedback ultrasonic signals to obtain Nt×N×N A-scan signals;

[0031] The Nt×N×N A-scan signals are intercepted and processed according to the transmission matrix sequence number to obtain the N×N first receiving full matrix data P r .

[0032] Optionally, the step of obtaining the thickness of each dielectric layer in the test block includes:

[0033] According to the sound velocity of each layer of the test block, the boundary layer image of the adjacent layers of the test block is obtained by B-scan imaging;

[0034] The thickness of each layer of medium is determined based on the boundary layer image.

[0035] Optionally, the creation and the first receiving of the full matrix data P r The corresponding Nt×N×N first emission full matrix data P t The steps include:

[0036] Create and first receive full matrix data P r The first emission full matrix data P of the same dimension and size Nt×N×N t , the first emission full matrix data Pt The expression is as follows:

[0037]

[0038] Where N is the number of array elements; Nt is the sampling length; x is the horizontal coordinate of the transmitting array element; t is the transmission time; j is the transmitting array element sequence number, j is 1, 2, 3, ... N.

[0039] The present invention provides an ultrasonic phased array phase shift rapid imaging method for multi-layer media, which transmits ultrasonic waves of a preset frequency to a test block through an array ultrasonic probe having N array elements, thereby obtaining receiving full matrix data corresponding to the N array elements and the thickness of each dielectric layer in the test block, and correspondingly creating receiving full matrix data corresponding to the receiving full matrix data, and then converting the first receiving full matrix data P r , first transmit full matrix data P t For each layer of the multi-layer medium, the image data of the medium of the corresponding layer is obtained according to the two-dimensional fast Fourier transform, Stolt interpolation processing and two-dimensional fast inverse Fourier transform. After the medium processing of all layers is completed, the image data of each layer of the medium are arranged in the order of the medium serial number to obtain the reconstructed test block image. Among them, the array ultrasonic probe with N array elements is used to obtain full matrix information, thereby achieving complete acquisition of the internal defect information of the test block, and the introduction of Stolt interpolation processing in data processing effectively improves the ultrasonic detection imaging efficiency inside the test block with a laminated structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a flow chart of a first embodiment of an ultrasonic phased array phase shift rapid imaging method for multilayer media according to the present invention;

[0041] Figure 2 for Figure 1 A schematic diagram of the structure of ultrasound data acquisition and display in the embodiment shown;

[0042] Figure 3 for Figure 1 A schematic diagram of N array elements transmitting and receiving ultrasonic signals in the illustrated embodiment;

[0043] Figure 4 for Figure 1 A schematic flow chart of detailed steps of step S400 in the illustrated embodiment;

[0044] Figure 5 This is a schematic structural diagram of a test block implementation of a second embodiment of an ultrasonic phased array phase shift rapid imaging method for multilayer media according to the present invention;

[0045] Figure 6 This is an imaging diagram of a full focusing algorithm based on ray tracing in the prior art;

[0046] Figure 7 This is an imaging image obtained using an ultrasonic phased array phase shift rapid imaging method for multilayer media according to the present invention.

[0047] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0048] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0049] Reference Figure 1 , which is a flow chart of a first embodiment of a method for rapid ultrasonic phased array phase shift imaging of multilayer media according to the present invention, the method comprises the following steps:

[0050] Step S100: Obtain the Nt×N×N first receiving full matrix data P obtained by the test block transmitting ultrasonic waves in sequence through the ultrasonic probe. r , wherein the ultrasonic probe has N array elements; Nt is the sampling length; and the test block is a laminated structure containing multiple layers of media.

[0051] Specifically, in practical applications, Figure 2 As shown, an array ultrasonic probe 20 with a total number of N array elements is placed on the surface of the test block 10, and the ultrasonic probe 20 is connected to a corresponding ultrasonic system host 30. The ultrasonic system host 30 is used to transmit a predetermined sampling frequency signal to the probe 20, thereby realizing that a single transmitting array element transmits ultrasonic waves to the test block of the laminated structure at a predetermined sampling frequency, and receives the feedback ultrasonic signals through all N array elements, as shown in FIG. Figure 3 As shown, N array elements transmit in sequence, and N array elements also successively receive different ultrasonic signals transmitted to each array element, and then N array elements transmit and receive ultrasonic signals to obtain Nt×N×N A-scan signals; in order to facilitate subsequent data processing and analysis, the data in the A-scan signal is further intercepted and divided according to the transmission matrix sequence number, that is, the first receiving full matrix data P is obtained. r (x, z = 0, t | j), where x is the horizontal coordinate of the receiving element, t is the receiving time, j is the serial number of the transmitting element, j is 1, 2, 3, ... N, and the sampling frequency range is set to 62.5 MHz.

[0052] Step S200 : obtaining the thickness of each layer of medium in the test block, and creating corresponding medium serial numbers from the surface layer medium to the bottom layer medium according to the distribution of each layer of medium.

[0053] Specifically, the corresponding medium serial numbers from the surface medium to the bottom medium are created according to the distribution of each layer of medium. For example, let the total number of medium layers be L, and the current medium serial number be M (the serial number increases from the probe contacting the surface layer to the bottom, M is 1, 2, 3...). At the same time, the corresponding medium sound velocity c(M) is obtained by looking up the table according to the material of each layer of medium in the test block, and the boundary layer image of the adjacent layers of the test block is obtained by the existing B-scan imaging method, and then the thickness d of each layer of medium is determined by the boundary layer image. M Furthermore, the thickness information of the first layer of media can be acquired not only through synthetic B-scan imaging, but also through other algorithms, such as total focusing algorithm imaging and wavenumber algorithm imaging. Furthermore, the present invention can not only acquire thickness information through layer-by-layer progressive imaging when the thickness is unknown, thereby completing the detection of multi-layer media objects, but can also record the thickness information and media serial number of the corresponding layer of media when the thickness is known.

[0054] Step S300, creating the first received full matrix data P r The corresponding Nt×N×N first emission full matrix data P t Specifically, create and receive the first full matrix data P r The first transmitted full matrix data P of Nt×N×N format consistent with (x, z=0,t|j) t (x, z = 0, t | j), where Nt is the sampling length; x is the horizontal coordinate of the transmitting element; t is the transmission time; j is the transmitting element number, j is 1, 2, 3, ... N. The transmitting signal can be a modulated sinusoidal pulse signal actually transmitted or an ideal pulse signal, that is, the setting is as follows:

[0055]

[0056] Step S400: receiving the first received full matrix data P r , first transmit full matrix data P t Obtaining image data of the medium of the corresponding layer according to two-dimensional fast Fourier transform, Stolt interpolation processing and two-dimensional fast inverse Fourier transform, and recording the medium serial number of the medium of the corresponding layer;

[0057] Step S500 : When the created medium serial numbers all match the recorded medium serial numbers one by one, the image data of each layer of the medium are arranged according to the medium serial numbers to obtain a reconstructed test block image.

[0058] In this embodiment, an array ultrasonic probe having N array elements transmits ultrasonic waves of a preset frequency to the test block, thereby obtaining the receiving full matrix data corresponding to the N array elements and the thickness of each dielectric layer in the test block, and correspondingly creating the receiving full matrix data corresponding to the receiving full matrix data, and then converting the first receiving full matrix data Pr , first transmit full matrix data P t For each layer of the multi-layer medium, the image data of the medium of the corresponding layer is obtained according to the two-dimensional fast Fourier transform, Stolt interpolation processing and two-dimensional fast inverse Fourier transform. After all layers of the medium are processed, the image data of each layer of the medium are arranged in the order of the medium serial number to obtain a reconstructed test block image. Herein, the full matrix information is obtained by adopting an array ultrasonic probe with N array elements. Based on the different transmission performance of ultrasonic waves in media of different materials and shapes, the actual data presented by ultrasonic waves in each medium of the test block can be accurately obtained, and the internal defect information of the test block can be fully obtained. Stolt interpolation processing is introduced in data processing, which effectively improves the ultrasonic detection imaging efficiency inside the test block with a laminated structure.

[0059] Furthermore, when the created medium serial number does not completely match the recorded medium serial number, the image data of the medium corresponding to the unmatched medium serial number is continuously reconstructed, and step S400 is repeated. At the same time, in order to facilitate the processing of each layer of media, the first received full matrix data P r , first transmit full matrix data P t The order from the surface medium to the bottom medium is obtained according to the two-dimensional fast Fourier transform, Stolt interpolation processing and two-dimensional fast inverse Fourier transform to obtain the image data of the medium of the corresponding layer, and the medium serial number of the corresponding layer is recorded. Then, when the recorded medium serial number is the bottom medium serial number, the image data of each layer of the medium are arranged in the order of the medium serial number to obtain the reconstructed test block image. It can be realized that the processing order of each layer of the medium is from the surface medium to the bottom medium in the order of the medium serial number to reconstruct the image data of each medium. When the recorded medium serial number is the bottom medium serial number, the reconstruction of the test block image can be started, and then the reconstruction operation of the corresponding test block image is terminated, thereby facilitating the improvement of the efficiency of the test block image reconstruction.

[0060] Furthermore, if Figure 4 As shown, the step S400 further includes:

[0061] Step S410: receiving the first received full matrix data P r , first transmit full matrix data P t Perform a two-dimensional fast Fourier transform to obtain the corresponding second receiving full matrix data P r2 , the second transmission full matrix data P t2 Specifically, along the time axis t and the space axis x, P r and P t Performing a two-dimensional fast Fourier transform (FFT2) yields the following:

[0062] P t2 (k x , z=0,ω|j)=FFT2(p t (x, z = 0, t | j));

[0063] P r2 (k x , z=0,ω|j)=FFT2(p r (x, z = 0, t | j));

[0064] Among them, k x is the x-component sequence of the wave number vector:

[0065]

[0066] ω is the angular frequency sequence:

[0067] Where N is the number of array elements; pitch is the element spacing; f s is the sampling frequency; Nt is the sampling length.

[0068] Furthermore, after step S410, the method further includes:

[0069] Step S420: According to the sound velocity c(M) of the current dielectric layer and the dielectric layer thickness d on the current dielectric layer M, M-1 Each second received full matrix data P r2 , the second transmission full matrix data P t2 The phase shift extends to the surface of the current dielectric layer, and the third receiving full matrix data P is obtained. r3 , the third emission full matrix data P t3 ;

[0070]

[0071]

[0072] Wherein, j is the transmitting array element number; j = 1, 2, 3, ... N; The total number of medium layers is L, the current medium number is M, and M is 1, 2, 3, ..., L; d M-1 is the thickness of the M-1th layer of medium; d0 = 0, k x is the horizontal wave number; z M is the depth information of the starting depth of recording from the surface of the M-th layer of medium; ω is the angular frequency.

[0073] as well as, sgn(ω) is the sign function of ω.

[0074] Furthermore, imaging is performed in the current medium layer, including:

[0075] Preset the wave vector in the z direction of the imaging area in the current medium layer,

[0076]

[0077] Wherein, Δz is the spacing of the pixels in the imaging area in the z direction, N z is the number of pixels, and Kz is the sequential sequence.

[0078] And for ω(k x ,k z ) Take the partial derivative and get According to the dispersion equation:

[0079]

[0080] Where ω(k x ,k z ) is to press k x 、k z The sequential sequence is calculated.

[0081] Step S430: receive the full matrix data P r3 , the third emission full matrix data P t3 Perform stolt interpolation processing to obtain the corresponding fourth received full matrix data P r4 , the fourth emission full matrix data P t4 .

[0082] Specifically, each third received full matrix data P r3 , the third emission full matrix data P t3 Slice the data in the order of j=1, 2, 3, ..., N to obtain the corresponding sliced data, and then perform stolt interpolation on the processed data. r3 (k x ,z M =0,ω|j)Stolt interpolation value P r3 (k x ,z M =0,ω(k x ,k z )|j),

[0083] Right now,

[0084] Similarly,

[0085] Furthermore, after step S430, the method further includes:

[0086] Step S440: receive the full matrix data P r4 , the fourth emission full matrix data P t4 Perform a two-dimensional fast inverse Fourier transform to obtain image data of the corresponding dielectric layer.

[0087] Specifically, each fourth received full matrix data P r4 , the fourth emission full matrix data P t4 Multiply and perform two-dimensional inverse fast Fourier transform to obtain the image data unit I of the corresponding medium layer j (x,2z);

[0088] Each image data unit I of each medium layer j (x, 2z) is superimposed to obtain the image data of the corresponding medium layer, that is,

[0089]

[0090] Since z=z+1 to z=2z is a redundant region, I is selected. M In (x, 2z), the imaging result I is obtained from the area z = 0 to z = z. M (x,z).

[0091] Furthermore, the step S500 specifically includes:

[0092] According to the image data I obtained for each layer of medium M The dielectric layers M are arranged in order from the surface layer to the bottom layer to obtain a multi-layer dielectric stacking structure image.

[0093] Furthermore, in order to verify the effect of the ultrasonic phased array phase shift rapid imaging method for multilayer media of the present invention, the following examples are provided for verification, wherein some selected devices are as follows: Figure 2 As shown, it includes a probe 20 for acquiring ultrasound data, an ultrasound system host 30, and a PC host 40 for data processing and image display. The probe 20 is a 64-element phased array probe, the ultrasound system host 30 is a 64-bit multi-channel Vantage ultrasound system, and the PC host 40 is installed with corresponding processing software, preferably MATLAB software; specifically, the test block 10 is as shown in FIG. Figure 5 As shown, the test block 10 is a laminated structure model of a rectangular resin wedge 11 with a width of 40 mm and a material of 45# steel 12. The test results of the present invention are as follows: Figure 7 As shown in the figure, the imaging result is an image with a resolution of 939*481, and the processing time is only 18s. In addition, the same test block 10 is imaged using the existing ray tracing-based full focusing algorithm. The specific results are as follows: Figure 6As shown, the imaging time of the full focusing algorithm based on ray tracing is 2470s. The processing time of the prior art far exceeds the time required for the processing of the present invention. It can be seen that the present invention can realize the imaging of the stacked structure, and the imaging speed is fast.

[0094] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or system comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or system. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or system comprising the element.

[0095] The serial numbers of the above embodiments of the present invention are for description only and do not represent the advantages or disadvantages of the embodiments.

[0096] Through the description of the above embodiments, those skilled in the art can clearly understand that the above embodiment methods can be implemented by means of software plus the necessary general hardware platform, and of course can also be implemented by hardware, but in many cases the former is a better embodiment. Based on this understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes a number of instructions for enabling a terminal device (which can be a mobile phone, computer, server, air conditioner, or network device, etc.) to execute the methods described in each embodiment of the present invention.

[0097] The above are only preferred embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for rapid phase shift imaging of multi-layer media using an ultrasonic phased array, characterized in that: The method comprises the following steps: Step 100: Obtain the Nt×N×N first receiving full matrix data P obtained by sequentially transmitting ultrasonic waves through the ultrasonic probe to the test block. r , wherein the ultrasonic probe has N array elements, Nt is the sampling length, and the test block is a laminated structure containing multiple layers of dielectrics; Step S200, obtaining the thickness of each layer of medium in the test block, and creating corresponding medium serial numbers from the surface layer medium to the bottom layer medium according to the distribution of each layer of medium; Step S300, creating the first received full matrix data P r The corresponding Nt×N×N first emission full matrix data P t ; Step S400: receiving the first received full matrix data P r , first transmit full matrix data P t Obtaining image data of the medium of the corresponding layer according to two-dimensional fast Fourier transform, Stolt interpolation processing and two-dimensional fast inverse Fourier transform, and recording the medium serial number of the medium of the corresponding layer; Step S500: When the created medium serial numbers all match the recorded medium serial numbers, the image data of each layer of the medium are arranged in the order of the medium serial numbers to obtain a reconstructed test block image; Wherein, the first received full matrix data P in step S400 is r , first transmit full matrix data P t The step of obtaining image data of the medium of the corresponding layer according to two-dimensional fast Fourier transform, Stolt interpolation processing and two-dimensional fast inverse Fourier transform includes: The first received full matrix data P r , first transmit full matrix data P t The image data of the corresponding layers of media are obtained from the surface layer of media to the bottom layer of media according to two-dimensional fast Fourier transform, Stolt interpolation processing and two-dimensional fast inverse Fourier transform, and the media serial number of the corresponding layer of media is recorded; When the recorded medium serial number is the bottom layer medium serial number, the image data of each layer of media are arranged in the order of the medium serial number to obtain a reconstructed test block image; Step S300 specifically includes: Create the first received full matrix data P r The first emission full matrix data P of the same dimension and size Nt×N×N t , the first transmitted full matrix data P t The expression is as follows: Where N is the number of array elements; Nt is the sampling length; x is the horizontal coordinate of the transmitting array element; t is the transmission time; j is the transmitting array element sequence number, j is 1, 2, 3, ... N.

2. The ultrasonic phased array phase shift rapid imaging method for multi-layer media according to claim 1, characterized in that: The first received full matrix data P r , first transmit full matrix data P t The step of obtaining image data of the medium of the corresponding layer according to two-dimensional fast Fourier transform, Stolt interpolation processing and two-dimensional fast inverse Fourier transform also includes: Step S410: receiving the first received full matrix data P r , first transmit full matrix data P t Perform a two-dimensional fast Fourier transform to obtain the corresponding second receiving full matrix data P r2 , the second transmission full matrix data P t2 .

3. The ultrasonic phased array phase shift rapid imaging method for multi-layer media according to claim 2, characterized in that: The first received full matrix data P r , first transmit full matrix data P t The step of obtaining image data of the medium of the corresponding layer according to two-dimensional fast Fourier transform, Stolt interpolation processing and two-dimensional fast inverse Fourier transform also includes: Step S420: The second received full matrix data P is converted into a matrix according to the current medium sound velocity and the current medium thickness. r2 , the second transmission full matrix data P t2 The phase migration extends to the current medium surface layer, and the third receiving full matrix data P is obtained. r3 , the third emission full matrix data P t3 , the specific formula is as follows: Wherein, j is the transmitting array element number; j = 1, 2, 3, ... N; The total number of medium layers is L, the current medium number is M, and M is 1, 2, 3, ..., L; d M-1 is the thickness of the M-1th layer of medium, d0=0; k x is the horizontal wave number; z M is the depth information of the starting depth of recording from the surface of the M-th layer of medium; ω is the angular frequency.

4. The ultrasonic phased array phase shift rapid imaging method for multi-layer media according to claim 3, characterized in that: The third received full matrix data P is obtained r3 , the third emission full matrix data P t3 After the steps, it also includes: Step S430: receive the full matrix data P r3 , the third emission full matrix data P t3 Perform stolt interpolation processing to obtain the corresponding fourth received full matrix data P r4 , the fourth emission full matrix data P t4 , the specific formula is as follows: in, 5. The ultrasonic phased array phase shift rapid imaging method for multi-layer media according to claim 4, characterized in that: The corresponding fourth received full matrix data P is obtained r4 , the fourth emission full matrix data P t4 After the steps, it also includes: Step S440: receive the full matrix data P r4 , the fourth emission full matrix data P t4 Perform a two-dimensional fast inverse Fourier transform and superimpose the transmit array elements to obtain the image data of the corresponding layer of the medium. The specific formula is as follows:

6. The ultrasonic phased array phase shift rapid imaging method for multilayer media according to any one of claims 3 to 5, characterized in that: The step of obtaining Nt×N×N first receiving full matrix data obtained by sequentially transmitting ultrasonic waves through the ultrasonic probe to the test block includes: Controlling the N array elements in the ultrasonic probe to sequentially transmit ultrasonic waves of a predetermined frequency to the test block and successively receiving the feedback ultrasonic signals to obtain Nt×N×N A-scan signals; The Nt×N×N A-scan signals are sliced to obtain Nt×N first received full matrix data.

7. The ultrasonic phased array phase shift rapid imaging method for multi-layer media according to claim 6, characterized in that: The step of obtaining the thickness of each dielectric layer in the test block includes: According to the sound velocity of each layer of the test block, the boundary layer image of the adjacent layers of the test block is obtained by B-scan imaging; The thickness of each layer of medium is determined based on the boundary layer image.

Images