A method for full-focus denoising imaging of ultrasonic phased array

Abstract

The present invention relates to the field of nondestructive testing technology, and specifically to an ultrasonic phased array full-focus denoising imaging method. The present invention is aimed at the fact that ultrasonic phased array detection defects are easily affected by noise in the scattering, attenuation and propagation processes. Different from the previous denoising method starting from the image, the present invention performs denoising and reconstruction starting from the ultrasonic signal itself, and then performs imaging, which essentially achieves the purpose of removing noise, optimizes the imaging results, and can effectively improve the accuracy of ultrasonic imaging.

Description

Technical Field

[0001] The invention relates to the technical field of nondestructive testing, and in particular to an ultrasonic phased array full-focus denoising imaging method. Background Art

[0002] Ultrasonic phased array technology is an imaging technology used in medicine, industry and other fields. It uses the propagation characteristics of ultrasonic waves inside the object being measured to perform imaging. Phased array technology allows images to be formed by adjusting the direction of ultrasonic emission and reception, thereby improving resolution and positioning accuracy of the target. However, in existing ultrasonic phased array detection, due to various reasons, such as scattering, attenuation, and noise during propagation, the acquired image may contain noise, thereby reducing the image quality and the ability to identify the target. It can be seen that denoising technology has become crucial in ultrasonic phased array imaging. Summary of the invention

[0003] In order to avoid and overcome the technical problems existing in the prior art, the present invention provides an ultrasonic phased array full-focus denoising imaging method, which can effectively improve the accuracy of ultrasonic imaging.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] 1. An ultrasonic phased array full-focus denoising imaging method comprises the following steps:

[0006] S1. Determine a point to be detected of the detection object, transmit phased ultrasound to the point to be detected by an ultrasonic phased array detection device, and obtain an echo signal received by each array element at the point to be detected;

[0007] S2. Performing empirical mode decomposition on the echo signal of each array element to obtain an initial signal corresponding to each array element;

[0008] S3, performing wavelet threshold denoising processing on the initial signal of each array element to obtain a denoised signal corresponding to each array element;

[0009] S4, performing time-domain delay superposition processing on the denoised signals of each array element to obtain a superposition signal corresponding to each array element;

[0010] S5, performing singular value decomposition on the full matrix data formed by the superposition signals of each array element and extracting singular values ​​for reconstruction, thereby obtaining new full matrix data through reconstruction;

[0011] S6. Based on the new full-matrix data, full-focus imaging is performed to obtain an ultrasonic image of the point to be detected.

[0012] As a further solution of the present invention: the initial signal is specifically expressed as follows:

[0013] ;

[0014] In the formula, (x, z) represents the coordinates of the point to be detected in the three-dimensional space coordinate system, x represents the coordinates of the point to be detected on the X-axis in the three-dimensional space coordinate system, and z represents the coordinates of the point to be detected on the Z-axis in the three-dimensional space coordinate system; represents the initial signal of the i-th array element in the ultrasonic probe at the point to be detected (x, z) at time t; represents the modal component of the ultrasonic signal emitted by the jth array element received by the i-th array element in the ultrasonic probe at the point to be detected (x, z) at time t; It represents the residual component of the ultrasonic signal emitted by the jth array element received by the i-th array element in the ultrasonic probe at the point to be detected (x, z) at time t; N represents the total number of array elements in the ultrasonic probe.

[0015] As a further solution of the present invention, the superimposed signal is specifically expressed as follows:

[0016] ;

[0017] ;

[0018] In the formula, It represents the superimposed signal obtained by the wavelet threshold denoising and time domain delay superposition processing of the initial signal sent by the jth array element received by the i-th array element in the ultrasonic probe at the point to be detected (x, z) at time t; It represents the time required for the i-th array element in the ultrasonic probe to receive the initial signal sent by the j-th array element at the point to be detected (x, z); It represents the denoised signal obtained by the initial signal sent by the jth array element received by the i-th array element in the ultrasonic probe at the detection point (x, z) at time t after the initial signal is denoised by the wavelet threshold; express The compensation coefficient of represents the signal emitted by the jth array element in the ultrasonic probe at time t; It represents the echo signal of the signal sent by the jth array element received by the i-th array element in the ultrasonic probe at the point to be detected (x, z) at time t.

[0019] As a further solution of the present invention: after obtaining the superposition signals of each array element, they are combined to form the full matrix data of the current point to be tested at the current moment, and then the full matrix data is subjected to singular value decomposition, and the analyzed matrices are combined and reconstructed to form new full matrix data, and then full focusing imaging is performed according to the full focusing imaging algorithm to obtain the ultrasonic image of the current point to be tested at the current moment.

[0020] As a further solution of the present invention: the threshold function in the wavelet threshold denoising process is specifically expressed as follows:

[0021] ;

[0022] ;

[0023] Where f represents the threshold function; sign represents the sign function; a represents the adjustment factor; e represents the natural constant; β represents the wavelet transform operator, |β| represents the absolute value of β; G represents the threshold constant; W represents the number of wavelet decomposition layers; H w represents the length of the detail component vector of the w-th layer wavelet coefficient; σ represents the adjustment factor; log represents the logarithmic function.

[0024] As a further solution of the present invention: the value of N is 64.

[0025] As a further solution of the present invention: the total number of singular values ​​in the singular value decomposition process is 30.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The ultrasonic phased array detection of defects is easily affected by noise in the scattering, attenuation and propagation process. Different from the previous denoising method starting from the image, the present invention performs denoising and reconstruction from the ultrasonic signal itself and then performs imaging, which essentially achieves the purpose of removing noise and optimizes the imaging results, thereby effectively improving the accuracy of ultrasonic imaging.

[0028] 2. The present invention improves the threshold function, overcomes the discontinuity of the existing hard threshold function and soft threshold function, optimizes the imaging effect, and improves the imaging signal-to-noise ratio.

[0029] 3. The present invention takes into account the characteristics of complex workpieces that are greatly affected by reflected echoes and coarse-grained materials with strong noise, and does not use a single noise reduction algorithm, but a combination of multiple algorithms, thereby essentially meeting the detection needs of various actual occasions, improving the signal-to-noise ratio of detection imaging, highlighting the defective image area, and weakening the noise area.

[0030] 4. The present invention proposes a compensation coefficient calculation formula for the full-focus imaging technology. This method can effectively suppress the ultrasonic sound velocity sidelobes, and each signal segment has a specific weight coefficient, so that the ultrasonic imaging has a better imaging effect in the entire scanning position and improves the signal-to-noise ratio. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is the main flow chart of the present invention.

[0032] Figure 2 It is the ultrasonic imaging diagram in the present invention.

[0033] Figure 3 It is a schematic diagram of the structure of the electronic device in the present invention. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] See also Figure 1 to Figure 3 In an embodiment of the present invention, a method for fully focusing denoising ultrasonic phased array imaging is provided, and the specific contents are as follows:

[0036] 1. Get the echo signal.

[0037] Determine the point to be tested of the test object, transmit phased ultrasound to the point to be tested through the ultrasonic phased array testing equipment, and obtain the echo signal received by each array element at the point to be tested. The ultrasonic testing equipment used in the test includes: a 64-element ultrasonic probe with an array element center distance of 0.60mm and a nominal center frequency of 5MHz, a Micropulse FMC phased array controller, a computer with a phased array testing platform operating environment, and a test block.

[0038] 2. Get the initial signal.

[0039] Perform empirical mode decomposition on the echo signal of each array element to obtain the initial signal corresponding to each array element. The initial signal is specifically shown in formula (1):

[0040] (1);

[0041] 3. Obtain the denoised signal.

[0042] The initial signal of each array element is subjected to wavelet threshold denoising processing to obtain the denoised signal corresponding to each array element.

[0043] The threshold function in wavelet threshold denoising is specifically shown in formula (2) and formula (3):

[0044] (2);

[0045] (3);

[0046] The present invention proposes a compensation coefficient calculation formula for the full-focus imaging technology. This method can effectively suppress the ultrasonic sound velocity sidelobes, and each signal segment has a specific weight coefficient, so that the ultrasonic imaging has a better imaging effect in the entire scanning position and improves the signal-to-noise ratio.

[0047] 4. Obtain the superimposed signal.

[0048] The denoised signals of each array element are subjected to time domain delay superposition processing to obtain the superposition signal corresponding to each array element. The superposition signal is specifically shown in formula (4) and formula (5):

[0049] (4);

[0050] (5);

[0051] 5. Get the full matrix data.

[0052] After obtaining the superposition signals of each array element, they are combined to form the full matrix data of the current test point at the current moment, and then the full matrix data is subjected to singular value decomposition. The total number of singular values ​​in the singular value decomposition process is 30, and the analyzed matrices are combined and reconstructed to form new full matrix data.

[0053] 6. Ultrasound imaging.

[0054] Based on the new full matrix data, full focus imaging is performed to obtain an ultrasonic image of the point to be detected. The ultrasonic image in the embodiment of the present invention is as follows: Figure 2 shown.

[0055] like Figure 3 As shown, the electronic device 10 includes one or more processors 11 and corresponding memory 12 .

[0056] The processor 11 may be a central processing unit or other forms of processing units having data processing capabilities and / or instruction execution capabilities, and may control other components in the electronic device 10 to perform desired functions. The memory 12 may include one or more computer program products, which may include various forms of computer storage media, such as volatile memory and / or non-volatile memory. The volatile memory may include, for example, a random access memory (RAM) and / or a cache memory (cache), etc. The non-volatile memory may include, for example, a read-only memory (ROM), a hard disk, a flash memory, etc. One or more computer program instructions may be stored on the computer storage medium, and the processor 11 may run the program instructions to implement the decision behavior decision method and / or other desired functions of the various embodiments of the present application described above.

[0057] In the example, the electronic device 10 may further include: an input device 13 and an output device 14, which are interconnected via a bus system and / or other forms of connection mechanisms (not shown). For example, the input device 13 may also include a keyboard, a mouse, etc. The output device 14 may include, for example, a display, a speaker, a printer, a communication network and a remote output device connected thereto, etc.

[0058] Of course, to simplify, Figure 3 Only some of the components related to the present application in the electronic device 10 are shown, and components such as a bus, an input / output interface, etc. are omitted. In addition, according to specific application situations, the electronic device 10 may also include any other appropriate components.

[0059] In addition to the above-mentioned methods and devices, the embodiments of the present application may also extend to a computer program product, which includes computer program instructions, which, when executed by a processor, enable the processor to execute the steps of the decision-making behavior decision method according to various embodiments of the present application described in the above-mentioned "Exemplary Method" section of this specification.

[0060] The computer program product may be written in any combination of one or more programming languages ​​to write program codes for performing the operations of the embodiments of the present application, including object-oriented programming languages, such as Java, C++, etc., and conventional procedural programming languages, such as "C" language or similar programming languages. The program code may be executed entirely on the user computing device, partially on the user device, as an independent software package, partially on the user computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0061] In addition, an embodiment of the present application may also be a readable computer storage medium on which computer program instructions are stored. When the computer program instructions are executed by a processor, the processor executes the steps of the decision-making behavior decision-making method according to various embodiments of the present application described in the above specific implementation process section of this specification.

[0062] The computer storage medium may be any combination of one or more readable media. The readable medium may be a readable signal medium or a storage medium. The storage medium may include, for example, but is not limited to, a system, device or device of electricity, magnetism, light, electromagnetic, infrared, or semiconductor, or any combination of the above. More specific examples of storage media (a non-exhaustive list) include: an electrical connection with one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0063] Of course, it will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0064] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. An ultrasonic phased array denoising imaging method, characterized in that: The following steps are involved: S1. Determine a point to be detected of the detection object, transmit phased ultrasound to the point to be detected by an ultrasonic phased array detection device, and obtain an echo signal received by each array element at the point to be detected; S2. Performing empirical mode decomposition on the echo signal of each array element to obtain an initial signal corresponding to each array element; S3, performing wavelet threshold denoising processing on the initial signal of each array element to obtain a denoised signal corresponding to each array element; S4, performing time-domain delay superposition processing on the denoised signals of each array element to obtain a superposition signal corresponding to each array element; S5, performing singular value decomposition on the full matrix data formed by the superposition signals of each array element and extracting singular values ​​for reconstruction, thereby obtaining new full matrix data through reconstruction; S6. Based on the new full matrix data, full focus imaging is performed to obtain an ultrasonic image of the point to be detected; The initial signal is specifically expressed as follows: ； Wherein, (x, z) represents the coordinates of the point to be detected in the three-dimensional space coordinate system, x represents the coordinates of the point to be detected on the X-axis of the three-dimensional space coordinate system, and z represents the coordinates of the point to be detected on the Z-axis of the three-dimensional space coordinate system; represents the initial signal of the i-th array element in the ultrasonic probe at the point to be detected (x, z) at time t; represents the modal component of the ultrasonic signal emitted by the jth array element received by the i-th array element in the ultrasonic probe at the point to be detected (x, z) at time t; represents the residual component of the ultrasonic signal emitted by the jth array element received by the i-th array element in the ultrasonic probe at the point to be detected (x, z) at time t; N represents the total number of array elements in the ultrasonic probe; The threshold function in wavelet threshold denoising is specifically expressed as follows: ； ； Where f represents the threshold function; sign represents the sign function; a represents the adjustment factor; e represents the natural constant; β represents the wavelet transform operator, |β| represents the absolute value of β; G represents the threshold constant; W represents the number of wavelet decomposition layers; H w represents the length of the detail component vector of the w-th layer wavelet coefficient; σ represents the adjustment factor; log represents the logarithmic function; The superimposed signal is specifically expressed as follows: ； ； In the formula, It represents the initial signal sent by the jth array element received by the i-th array element in the ultrasonic probe at the point to be detected (x, z) at time t, and the superimposed signal obtained after the wavelet threshold denoising and time domain delay superposition processing; It represents the time required for the i-th array element in the ultrasonic probe to receive the initial signal sent by the j-th array element at the point to be detected (x, z); It represents the initial signal sent by the jth array element received by the i-th array element in the ultrasonic probe at the detection point (x, z) at time t, and the denoised signal obtained after the wavelet threshold denoising process; express The compensation coefficient of represents the signal emitted by the jth array element in the ultrasonic probe at time t; It represents the echo signal of the signal sent by the jth array element received by the i-th array element in the ultrasonic probe at the point to be detected (x, z) at time t.

2. The ultrasonic phased array denoising imaging method according to claim 1, characterized in that: After obtaining the superposition signals of each array element, they are combined to form the full matrix data of the current point to be tested at the current moment, and then the full matrix data is subjected to singular value decomposition, and the decomposed matrices are combined and reconstructed to form new full matrix data, and then full focusing imaging is performed according to the full focusing imaging algorithm to obtain the ultrasound image of the current point to be tested at the current moment.

3. The ultrasonic phased array denoising imaging method according to claim 2, characterized in that: The value of N is 64.

4. The ultrasonic phased array denoising imaging method according to claim 3, characterized in that: The total number of singular values ​​in the singular value decomposition process is 30.

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