Industrial CT particle beam magnetic field deflection artifact eliminating device

Abstract

The utility model provides an artifact eliminating device for industrial CT particle beam magnetic field deflection, which comprises a cathode, a deflection coil assembly, a target surface, a detected body and a detector, charged particles are emitted through the cathode and fly to the target surface through the deflection coil assembly, the deflection coil assembly can change the vertical incidence point of the charged particles, and the detected body is detected. Different focuses are formed on the target surface, and rays formed by each focus respectively pass through a detected body and then are collected by a detector. Under the condition that the physical channel number, the row number and the position of the detector are not changed, a plurality of sampling data are obtained in one-time scanning by periodically shifting the X-ray focus position, and then the resolution ratio is improved.

Description

Technical Field

[0001] The utility model belongs to the field of industrial CT, in particular to an artifact elimination device for industrial CT particle beam magnetic field deflection. Background Art

[0002] X-ray industrial inspection systems play a vital role in non-destructive testing, scientific research, medicine and other fields; they can provide images of the tomography of the irradiated object, including the nature, shape, location and size of the defects contained therein, which is very intuitive. However, due to factors such as the internal structure of the inspection object, the design of the CT system and the reconstruction algorithm, tomographic images often inevitably have artifacts, which interfere with the imaging effect;

[0003] 1. Artifact formation; In the practical application of industrial CT, the most common types of artifacts can be divided into three categories: ring artifacts, metal artifacts, and beam hardening artifacts;

[0004] 1. Ring artifacts: Damage to the detector pixel channel, nonlinearity and inconsistency in the pixel channel response to the intensity and energy spectrum of the ray, etc., lead to the appearance of concentric rings or arcs with different radii and thicknesses with the center of rotation as the center in the reconstructed image. The ring artifacts are more serious near the center of the circle. When the position of the bad point is fixed, the ring artifacts appear as linear artifacts of varying brightness in the sinusoidal diagram.

[0005] 2. Metal artifacts: For scanning objects with large density differences, banded artifacts will be generated between high-density objects, which appear in the image as stripes emanating from the metal area, bright or dark artifacts around the metal, and various noises. Radial artifacts are caused by the large difference between the attenuation coefficient of the metal and the attenuation coefficient of the surrounding material.

[0006] 3. Beam hardening artifacts: Due to the multi-energy characteristics of the radiation source in the CT system, as the depth of incidence increases, the attenuation of low-energy photons is greater than that of high-energy photons, the average energy of the radiation gradually increases, and the X-rays gradually "harden". However, the CT reconstruction algorithm is performed under the ideal premise that the radiation is monoenergetic, which leads to errors in the reconstruction results. The artifacts caused by this error are hardening artifacts. For scanned objects of uniform material, the most typical feature is the cup-shaped artifact, that is, the uniform material is black in the middle and bright at the edges.

[0007] In order to effectively eliminate the impact of artifacts on CT images, professional image acquisition and reconstruction software can be used to automatically calculate and correct image errors, effectively calibrate imaging deviations caused by inconsistent detector response areas and the complex structure of the detection object, thereby improving imaging quality.

[0008] Data is processed in the projection domain, usually by using a smoother convolution kernel to suppress the high-frequency components in the projection data. However, the disadvantage of this method is that it will cause the image details to be lost and become more blurred.

[0009] The image is Fourier transformed in the image domain, but the artifact features need to be accurately identified in order to extract the artifact features in the image by combining the relevant information in the spatial domain and the frequency domain.

[0010] In addition to correcting image errors through software, common methods in system hardware are 1 / 4 detector offset and flying focus technology.

[0011] 1 / 4 detector offset improves resolution and reduces artifacts by using data collected at opposite angles, but only ensures good results at the center of the detector's field of view. Utility Model Content

[0012] In view of this, the utility model aims to propose an artifact elimination device for industrial CT particle beam magnetic field deflection, which does not change the number of physical channels, rows and positions of the detector, and periodically shifts the X-ray focus position so that multiple sampling data can be obtained in one scan, thereby improving the resolution.

[0013] In order to achieve the above object, the technical solution of the utility model is implemented as follows:

[0014] An artifact elimination device for the magnetic field deflection of an industrial CT particle beam comprises a cathode, a deflection coil assembly, a target surface, a subject and a detector. Charged particles are emitted through the cathode and fly to the target surface through the deflection coil assembly.

[0015] The deflection coil assembly can change the vertical incident point of the charged particles to form different focal points on the target surface, and the rays formed by each focal point are collected by the detector after passing through the subject.

[0016] Furthermore, the deflection coil assembly includes a frame and a coil body, the frame is in a circular ring shape, and a through hole is formed in the middle for charged particles to pass through; four groups of coil bodies are evenly arranged in the inner cavity of the frame, and the four groups of coil bodies act on the charged particles. The coil body is sealed in the frame by sealing glue on one side of the frame.

[0017] Furthermore, an insulating sleeve is provided on the frame, and the insulating sleeve is connected to the inside of the frame for leading out the electrical signal.

[0018] Furthermore, one end of the outgoing wire of the coil body is led out at the connection between the sealing glue and the frame.

[0019] Furthermore, the four coil bodies have the same structure, and two joints are formed by winding copper wires, namely an inner circle copper wire joint and an outer circle copper wire joint.

[0020] Furthermore, the four coil bodies are X1, X2, Y1, and Y2 respectively; among them,

[0021] The inner copper wire connector of the coil body X1 is a1, and the outer copper wire connector is b1;

[0022] The inner copper wire connector of the coil body X2 is a2, and the outer copper wire connector is b2;

[0023] The inner copper wire connector of the coil body Y1 is a3, and the outer copper wire connector is b3;

[0024] The inner copper wire connector of the coil body Y2 is a4, and the outer copper wire connector is b4.

[0025] Further, a1 is connected to a2, and a3 is connected to a4;

[0026] One end of the outgoing line of the coil body includes b1, b2, b3 and b4, wherein b1 and b2 are respectively connected to the positive and negative poles of a power source, and b3 and b4 are respectively connected to the positive and negative poles of another power source.

[0027] Compared with the prior art, the artifact elimination device for industrial CT particle beam magnetic field deflection described in the utility model has the following advantages:

[0028] (1) The utility model discloses an artifact elimination device for industrial CT particle beam magnetic field deflection, which changes the position of the focus on the handle by means of the deflection magnetic field generated by the deflection coil. This method has accurate positioning and fast response speed, and avoids the shortcomings of complex detector jitter structure, slow response speed and inaccurate positioning. The focus can be shifted only by changing the current value of the deflection coil, and has good reliability and is easy to operate.

[0029] (2) The artifact elimination device for the deflection of the magnetic field of the industrial CT particle beam described in the utility model greatly reduces the influence of the artifacts on the test results, significantly improves the imaging quality and the reliability of the test results, and provides strong support for subsequent further three-dimensional non-destructive analysis, such as wall thickness measurement, pore crack analysis, size measurement, CAD comparison, reverse engineering, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the accompanying drawings:

[0031] Figure 1 A schematic diagram of an artifact elimination device for industrial CT particle beam magnetic field deflection according to an embodiment of the utility model;

[0032] Figure 2 A front view of a deflection coil assembly according to an embodiment of the utility model;

[0033] Figure 3A cross-sectional view of a deflection coil assembly according to an embodiment of the utility model;

[0034] Figure 4 This is a schematic diagram of the coil body described in an embodiment of the utility model.

[0035] Description of reference numerals:

[0036] 1. Cathode; 2. Deflection coil assembly; 21. Frame; 22. Coil body; 23. Insulating sleeve; 24. One end of the outlet wire; 25. Sealing glue; 3. Target surface; 4. Object to be tested; 5. Detector. DETAILED DESCRIPTION

[0037] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0038] In the description of the present utility model, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present utility model, unless otherwise specified, "multiple" means two or more.

[0039] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0040] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0041] An artifact elimination device for industrial CT particle beam magnetic field deflection, such as Figure 1-Figure 4As shown, it includes a cathode 1, a deflection coil assembly 2, a target surface 3, a test object 4 and a detector 5. Charged particles are emitted through the cathode 1 and fly to the target surface 3 through the deflection coil assembly 2.

[0042] The deflection coil assembly 2 can change the vertical incident point of the charged particles to form different focal points on the target surface 3 , and the rays formed by each focal point are collected by the detector 5 after passing through the subject 4 .

[0043] Preferably, the deflection coil assembly 2 includes a skeleton 21 and a coil body 22, the skeleton 21 is in a circular ring shape, and a through hole is formed in the middle for charged particles to pass through; the skeleton 21 is a hollow structure, forming an inner cavity, and four groups of coil bodies 22 are evenly arranged in the inner cavity of the skeleton 21, and the four groups of coil bodies 22 act on the charged particles. The coil bodies 22 are sealed in the skeleton 21 by sealing glue 25 on one side of the skeleton 21, and the four groups of coil bodies 22 are spaced 90° apart.

[0044] Preferably, an insulating sleeve 23 is provided on the skeleton 21, and the insulating sleeve 23 is connected to the inside of the skeleton 21 for leading out electrical signals.

[0045] Preferably, one end 24 of the coil body 22 is led out at the connection between the sealing glue 25 and the frame 21 .

[0046] Preferably, the four coil bodies 22 have the same structure, and two joints are formed by winding copper wires, namely an inner circle copper wire joint and an outer circle copper wire joint.

[0047] Preferably, the four coil bodies 22 are X1, X2, Y1, and Y2 respectively; wherein,

[0048] The inner copper wire connector of the coil body 22X1 is a1, and the outer copper wire connector is b1;

[0049] The inner copper wire connector of the coil body 22X2 is a2, and the outer copper wire connector is b2;

[0050] The inner copper wire connector of the coil body 22Y1 is a3, and the outer copper wire connector is b3;

[0051] The inner copper wire connector of the coil body 22Y2 is a4, and the outer copper wire connector is b4;

[0052] Preferably, a1 is connected to a2, and a3 is connected to a4;

[0053] The outgoing end 24 of the coil body 22 includes b1, b2, b3 and b4, wherein b1 and b2 are respectively connected to the positive and negative poles of one power source, and b3 and b4 are respectively connected to the positive and negative poles of another power source.

[0054] Working principle: When the charged particles emitted by the cathode 1 fly toward the target surface 3 at high speed, the deflection magnetic field generated by the deflection coil changes their vertical incident point, forming different focuses on the target surface 3. The rays formed by each focus pass through the subject 4 and are collected by the detector 5, and the corresponding data are obtained after processing; the image is reconstructed using the data of multiple focus projection views to improve the resolution.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An artifact elimination device for magnetic field deflection of industrial CT particle beam, characterized in that: It includes a cathode, a deflection coil assembly, a target surface, an object to be inspected, and a detector. Charged particles are emitted through the cathode and fly to the target surface through the deflection coil assembly. The deflection coil assembly can change the vertical incident point of the charged particles to form different focal points on the target surface, and the rays formed by each focal point are collected by the detector after passing through the subject.

2. The device for eliminating artifacts of the magnetic field deflection of an industrial CT particle beam according to claim 1, characterized in that: The deflection coil assembly includes a frame and a coil body. The frame is in a circular ring shape, and a through hole is formed in the middle for charged particles to pass through. Four groups of coil bodies are evenly arranged in the inner cavity of the frame, and the four groups of coil bodies act on the charged particles. The coil body is sealed in the frame by sealing glue on one side of the frame.

3. The device for eliminating artifacts of the magnetic field deflection of an industrial CT particle beam according to claim 2, characterized in that: An insulating sleeve is provided on the frame, and the insulating sleeve is connected to the inside of the frame for leading out electrical signals.

4. The device for eliminating artifacts of the magnetic field deflection of an industrial CT particle beam according to claim 2, characterized in that: One end of the outgoing wire of the coil body is led out at the connection between the sealing glue and the frame.

5. The device for eliminating artifacts of the magnetic field deflection of an industrial CT particle beam according to claim 2, characterized in that: The four coil bodies have the same structure, and two joints are formed by winding copper wires, namely an inner circle copper wire joint and an outer circle copper wire joint.

6. The device for eliminating artifacts of the magnetic field deflection of an industrial CT particle beam according to claim 5, characterized in that: The four coil bodies are X1, X2, Y1, and Y2 respectively; among them, The inner copper wire connector of the coil body X1 is a1, and the outer copper wire connector is b1; The inner copper wire connector of the coil body X2 is a2, and the outer copper wire connector is b2; The inner copper wire connector of the coil body Y1 is a3, and the outer copper wire connector is b3; The inner copper wire connector of the coil body Y2 is a4, and the outer copper wire connector is b4.

7. The device for eliminating artifacts of the magnetic field deflection of an industrial CT particle beam according to claim 6, characterized in that: a1 is connected to a2, and a3 is connected to a4; One end of the outgoing line of the coil body includes b1, b2, b3 and b4, wherein b1 and b2 are respectively connected to the positive and negative poles of a power source, and b3 and b4 are respectively connected to the positive and negative poles of another power source.

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