Spherical shell-shaped object detection method and system based on X rays

Abstract

The invention discloses a spherical shell-shaped object detection method and system based on X rays. The system comprises a main body frame, wherein a C-shaped arm, a flat panel detector, a flat panel detector position adjusting mechanism, an arc-shaped detector, an X-ray source, a ray source position adjusting mechanism and a sample table are arranged in the main body frame; the C-shaped arm is fixed at the top of the main body frame; a spherical-shell-shaped object to be detected is placed on the sample table, and the sphere center of the spherical-shell-shaped object is located on the circle center O corresponding to the C-shaped arm; the flat panel detector position adjusting mechanism adjusts the position of the flat panel detector on the C-shaped arm, and the central vertical line of the flat panel detector always intersects with the circle center O; the circle center of the arc-shaped detector coincides with the circle center O; the X-ray source scans a region of interest of the spherical shell-shaped object; the radiation source position adjusting mechanism adjusts the position of the radiation source. The method is suitable for detecting spherical shell-shaped objects, and DR imaging does not have distortion.

Description

Technical Field

[0001] The present invention belongs to the field of X-ray non-destructive testing, and relates to a detection method and system for spherical shell-shaped objects based on X-rays, which are used for defect-assisted identification, positioning, measurement and detection of material density uniformity of spherical shell-shaped objects. Background Art

[0002] Currently, X-ray computed tomography (CT) technology is a non-destructive testing method for effectively detecting three-dimensional information of the internal structure of an object, and has been widely used in fields such as industry and medical diagnosis. The scanned object has similar scales in three dimensions. However, for plate-shaped components such as multi-layer printed circuit boards, sheet fossils, aircraft wings, and solar panels, the imaging effect of CT technology is not satisfactory. In recent years, the research and development of X-ray computed laminography (CL) technology have attracted much attention. The object scanned by this technology is a flat object and is not suitable for curved samples.

[0003] In the current CL scheme of computed laminography, the radiation source is located below the device, and the stage is above the radiation source. The stage drives the flat sample to be detected and can perform horizontal translation movement in space. A fixed frame is set above the stage, and the fixed frame is connected to a rotating arm. The rotating arm can perform circular rotation movement. A flat panel detector is set on the rotating arm, and the detector can slide along an arc-shaped guide rail on the rotating arm. Scanning imaging can be performed at various specific positions of the flat panel according to specific needs.

[0004] As can be seen from the above, currently existing technologies basically use linear array detectors or area array detectors. For digital radiography (DR) of spherical shell-shaped objects, due to the inconsistency of the magnification ratio, serious distortion will occur in the DR image. Summary of the Invention

[0005] Aiming at the problems existing in the prior art, the purpose of the present invention is to provide a detection method and system for spherical shell-shaped objects based on X-rays. This solution combines an arc-shaped detector (the detection units are arranged in an arc shape) with a flat panel detector to solve the above problems. The device can achieve the following functions: (1) overall DR imaging; (2) local DR imaging; (3) local CL imaging.

[0006] The key points of the present invention are as follows:

[0007] 1) The device detector is fixed on the C-arm. The C-arm is simultaneously provided with an arc-shaped linear array detector and a flat panel detector. The flat panel detector can move along the C-arm to adjust the angle and position.

[0008] 2) The radiation source can move in multiple dimensions. It can move up and down along a linear track, move horizontally along a linear track, rotate around the center of an electric turntable, and swing along an arc track.

[0009] 3) Equipment functions. The equipment can perform overall DR imaging, and can also perform local CL imaging for local DR images.

[0010] The technical solution of the present invention is as follows:

[0011] An X-ray-based spherical shell object detection system, characterized in that it includes a main frame 1, and a C-arm 2, a flat panel detector 3, a flat panel detector position adjustment mechanism 4, an arc detector 5, an X-ray source 6, a radiation source position adjustment mechanism 7 and a sample stage 8 are arranged in the main frame 1;

[0012] The C-arm 2 is fixed at the top of the main frame 1;

[0013] The sample stage 8 is located in the middle of the main frame 1, and is used for placing the spherical shell object 9 to be detected and driving the spherical shell object 9 to rotate. The center of the spherical shell object 9 is located at the center O corresponding to the C-arm 2;

[0014] The flat panel detector 3 is installed on one side of the C-arm 2 through the flat panel detector position adjustment mechanism 4 and is used for receiving X-rays; the flat panel detector position adjustment mechanism 4 is used for adjusting the position of the flat panel detector 3 on the C-arm 2. During the movement of the position of the flat panel detector 3 on the C-arm 2, the central vertical line of the flat panel detector 3 always intersects with the center O;

[0015] The arc detector 5 is installed and fixed on the other side of the C-arm 2 and is used for receiving X-rays; the center of the arc detector 5 coincides with the center O;

[0016] The X-ray source 6 is installed on the radiation source position adjustment mechanism 7, located below the spherical shell object 9, and is used for generating X-rays to scan the region of interest of the spherical shell object 9;

[0017] The radiation source position adjustment mechanism 7 is located at the bottom of the main frame 1 and is used for adjusting the position of the X-ray source 6.

[0018] Furthermore, the sample stage 8 includes a marble platform 10, and a hollow turntable 11 for driving the spherical shell object 9 to rotate is arranged at the center of the marble platform 10; an adjustable bracket 12 is arranged on the hollow turntable 11 for supporting the spherical shell object 9 and adjusting the position of the spherical shell object 9 so that its center is located at the center O.

[0019] Further, the ray source position adjustment mechanism 7 includes a lifting mechanism 15, a linear module 16, an electric turntable 17, an arc track 18, a mechanism base 19, and a lower arc drive mechanism 20; the mechanism base 19 is fixed on the main body frame 1, the arc track 18 is installed on the mechanism base 19, and the lower arc drive mechanism 20 is installed on the arc track 18; the electric turntable 17 is installed on the lower arc drive mechanism 20; the lower arc drive mechanism 20 is used to drive the electric turntable 17 to swing around the center O of the arc track 18; the linear module 16 is provided on the electric turntable 17 for rotating the linear module 16; the lifting mechanism 15 is provided on the linear module 16 for controlling the movement of the lifting mechanism 15 in the horizontal plane; the X-ray source 6 is installed on the control lifting mechanism 15 for controlling the lifting of the X-ray source 6.

[0020] Further, the center of the arc track 18 coincides with the center O.

[0021] Further, the central angle of the arc detector 5 is not less than 90 degrees.

[0022] Further, a shielding structure is integrally provided on the outer side of the main body frame 1.

[0023] A method for detecting a spherical shell-shaped object based on the above system, the steps of which include:

[0024] 1) Place the spherical shell-shaped object 9 to be detected on the sample stage 8, and the center of the spherical shell-shaped object 9 is located at the center O corresponding to the C-shaped arm 2; move the X-ray source 6 to the position of the center O;

[0025] 2) Rotate the spherical shell-shaped object 9 one week. During the rotation process, use the emitted rays of the X-ray source 6 to scan the spherical shell-shaped object 9, and use the arc detector 5 to collect projection data;

[0026] 3) Establish a coordinate system for recording the projection data. The origin of this coordinate system corresponds to the vertex of the spherical shell-shaped object 9. The rotation angle α ∈ [0, 2π] of the spherical shell-shaped object 9 is the abscissa of this coordinate system, and the angle β ∈ [0, π / 2] between the ray corresponding to the projection data and the horizontal plane is the ordinate of this coordinate system; for any point P on the spherical shell-shaped object 9, the coordinates of this point P in this coordinate system are (α1, β1), and through coordinate mapping, the coordinates of this point P in the intuitive projection diagram in this coordinate system are (x1, y1), and its mapping relationship is

[0027] 4) Determine the region of interest on the spherical shell-shaped object 9 based on the intuitive projection diagram;

[0028] 5) Adjust the center of the region of interest to the direction where the flat panel detector 3 is located; adjust the position of the flat panel detector 3 so that the center of the flat panel detector 3 is close to the center of the region of interest; adjust the position of the X-ray source 6 so that the line connecting its focal point and the center of the flat panel detector 3 passes through the central region of the position of the region of interest; then adjust the height of the X-ray source 6 to obtain the required magnification ratio, the X-ray emitted by the X-ray source 6 scans the region of interest, and the flat panel detector 3 is used to collect projection data to obtain a high-resolution intuitive projection image corresponding to the region of interest.

[0029] A method for detecting a spherical shell-shaped object based on the above system, the steps of which include:

[0030] 1) Place the spherical shell-shaped object 9 to be detected on the sample stage 8, and the center of the spherical shell-shaped object 9 is located at the center O of the circle corresponding to the C-shaped arm 2; move the X-ray source 6 to the position of the center O;

[0031] 2) Rotate the spherical shell-shaped object 9 one week, and during the rotation process, use the X-ray emitted by the X-ray source 6 to scan the spherical shell-shaped object 9, and use the arc detector 5 to collect projection data;

[0032] 3) Establish a coordinate system for recording the projection data. The origin of this coordinate system corresponds to the vertex of the spherical shell-shaped object 9. The rotation angle α of the spherical shell-shaped object 9 ∈ [0, 2π] is the abscissa of this coordinate system, and the angle β ∈ [0, π / 2] between the ray corresponding to the projection data and the horizontal plane is the ordinate of this coordinate system; for any point P on the spherical shell-shaped object 9, the coordinates of this point P in this coordinate system are (α1, β1), and through coordinate mapping, the coordinates of this point P in the intuitive projection image in this coordinate system are (x1, y1), and its mapping relationship is

[0033] 4) Determine the region of interest on the spherical shell-shaped object 9 based on the intuitive projection image;

[0034] 5) Adjust the position of the X-ray source 6 so that the horizontal distance between it and the center O is r, where r is the scanning radius of the X-ray source 6; rotate the X-ray source 6, and during the rotation process, use the X-ray emitted by the X-ray source 6 to scan the region of interest, and use the flat panel detector 3 to collect projection data, and obtain a three-dimensional tomographic image of the region of interest through the CL reconstruction algorithm; then determine the three-dimensional position of the defect on the spherical shell-shaped object 9 based on the three-dimensional tomographic image.

[0035] The advantages of the present invention are as follows:

[0036] 1) This solution uses an arc detector, and for a spherical shell-shaped object, there is no distortion in DR imaging.

[0037] 2) The structure of this solution is applicable to spherical shell-shaped objects and can perform local CL tomography. Description of the Drawings

[0038] Figure 1 It is a structural diagram of a spherical shell-shaped object detection device based on X-rays.

[0039] Figure 2 It is a schematic diagram of the structure of the sample stage.

[0040] Figure 3 It is a schematic diagram of the X-ray source and the position adjustment mechanism.

[0041] Figure 4 It is a flowchart of the overall DR imaging.

[0042] Figure 5 It is a two-dimensional global projection diagram.

[0043] Figure 6 It is an intuitive DR diagram.

[0044] Reference Numerals: 1 - main body frame, 2 - C-arm, 3 - flat panel detector, 4 - flat panel detector position adjustment mechanism, 5 - arc detector, 6 - X-ray source, 7 - ray source position adjustment mechanism, 8 - sample stage, 9 - spherical shell-shaped object, 10 - marble platform, 11 - hollow turntable, 12 - adjustable bracket, 15 - lifting mechanism, 16 - linear module, 17 - electric turntable, 18 - arc track, 19 - mechanism base, 20 - lower arc drive mechanism. Detailed Embodiment

[0045] The present invention will be further described in detail below with reference to the drawings. The examples given are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0046] As Figure 1 shown, the X-ray-based spherical shell-shaped object detection system of the present invention mainly includes: a main body frame 1, a C-arm 2, a flat panel detector 3, a flat panel detector position adjustment mechanism 4, an arc detector 5, an X-ray source 6, a ray source position adjustment mechanism 7, a sample stage 8, and a spherical shell-shaped object 9 to be detected.

[0047] The main body frame 1 includes a frame part and an outer shielding structure. The frame part is used to provide the overall structural foundation, and the shielding part is wrapped outside the frame for radiation safety protection.

[0048] The C-arm 2 is fixed above the main body frame 1. The flat panel detector 3 and the arc detector 5 are used to receive X-rays and are respectively installed on both sides of the C-arm 2. The flat panel detector 3 can move on the C-arm 2 through the flat panel detector position adjustment mechanism 4. During the movement, the central vertical line of the flat panel detector 3 always intersects at point O. The arc detector 5 is fixed on the C-arm 2 and its position remains unchanged. The center of the arc corresponds to the above-mentioned point O, and the central angle is not less than 90 degrees.

[0049] As Figure 3 shown, the X-ray source 6 is used to generate X-rays and is installed on the X-ray source position adjustment mechanism 7. The X-ray source position adjustment mechanism 7 includes: a lifting mechanism 15, which is driven by a motor to drive a ball screw and relies on a slider guide rail as a track to control the lifting of the X-ray source 6; a linear module 16 is used to move the X-ray source 6 and the lifting mechanism 15 a certain distance along the track direction; an electric turntable 17 is used to drive the upper mechanism to rotate around the turntable center; the lower arc driving mechanism 20 provides power for the entire mechanism above the electric turntable 17 to swing along the arc track 18, and the arc track 18 is centered on the above-mentioned point O; a mechanism base 19 provides support for the adjustment mechanism and is fixed on the main body frame 1.

[0050] As Figure 2 shown, the sample stage 8 is used to place the spherical shell-shaped object 9 and includes: a marble platform 10 to ensure the flatness of the surface to be detected; a hollow turntable 11 responsible for driving the spherical shell-shaped object 9 to rotate, which can rotate 360 degrees; an adjustable bracket 12 is used to support the spherical shell-shaped object 9 to ensure that the center of the spherical shell-shaped object 9 is located at the above-mentioned point O.

[0051] The work execution is described as follows:

[0052] 1) Overall DR imaging: Its working process is as Figure 4 shown.

[0053] The two-dimensional global projection image is as Figure 5 shown, where α ∈ [0, 2π] represents the sample rotation angle, and β ∈ [0, π / 2] represents the angle between the ray corresponding to the projection data and the horizontal plane. The black dot represents the position of the projection corresponding to point P on the sample, and its coordinates are (α1, β1).

[0054] To visually display the distribution of defects on the hemispherical sample, we define a new coordinate system, and the image generated based on this coordinate system is the intuitive projection image. The origin of this coordinate system corresponds to the vertex of the hemisphere. Figure 5 The coordinates of the point after mapping point P in

[0055]

[0056] As Figure 6As shown, according to the orthographic projection drawing, it is easy to locate the position of the sample defect point.

[0057] After the overall DR imaging is performed, the position of the large-size defect can be initially determined as the region of interest according to the intuitive DR image. To perform higher-resolution imaging of the defect, local high-resolution DR imaging can be used.

[0058] 2) Local DR imaging: According to the position of the region of interest of the spherical shell-shaped object 9 to be detected selected, rotate the hollow turntable 11 to turn the center of the region of interest position of the sample to the direction where the flat panel detector 3 is located. Adjust the position of the flat panel detector 3 to make the center of the flat panel detector 3 close to the center of the region of interest position. Adjust the position of the X-ray source 6 so that the line connecting its focus and the center of the flat panel detector 3 passes near the center of the region of interest position, and adjust the height of the X-ray source 6 to an appropriate magnification ratio. The X-ray source 6 emits rays, and the flat panel detector 3 collects data to obtain a local high-resolution DR image.

[0059] 3) Local CL imaging: Its preparation process is similar to that of local high-resolution DR imaging. Set the scanning radius of the focus of the X-ray source 6, assumed to be r, and move the X-ray source 6 a distance of r through the linear module 16. During scanning, the electric turntable 17 drives the X-ray source 6 to rotate with a radius of r, and at the same time the flat panel detector 3 collects projection data. After collecting 360 degrees of projection data, a three-dimensional tomographic image of the region of interest is obtained through the CL reconstruction algorithm. Based on this three-dimensional tomographic image, the three-dimensional position of the defect on the spherical shell can be analyzed.

[0060] Although specific embodiments of the present invention are disclosed for illustrative purposes, the purpose is to help understand the content of the present invention and implement it accordingly. Those skilled in the art can understand that: without departing from the spirit and scope of the present invention and the appended claims, various substitutions, changes, and modifications are possible. Therefore, the present invention should not be limited to the content disclosed in the best embodiments, and the scope of protection required by the present invention is subject to the scope defined by the claims.

Claims

1. An X-ray-based detection system for spherical shell-shaped objects, characterized in that, It includes a main body frame (1), inside which there are a C-arm (2), a flat panel detector (3), a flat panel detector position adjustment mechanism (4), an arc detector (5), an X-ray source (6), a ray source position adjustment mechanism (7) and a sample stage (8); The C-arm (2) is fixed at the top of the main body frame (1); The sample stage (8) is located in the middle of the main body frame (1), and is used to place a spherical shell-shaped object (9) to be detected and drive the spherical shell-shaped object (9) to rotate. The center of the spherical shell-shaped object (9) is located at the center O of the circle corresponding to the C-arm (2); The flat panel detector (3) is installed on one side of the C-arm (2) through the flat panel detector position adjustment mechanism (4) and is used to receive X-rays. The flat panel detector position adjustment mechanism (4) is used to adjust the position of the flat panel detector (3) on the C-arm (2). During the movement of the flat panel detector (3) on the C-arm (2), the central vertical line of the flat panel detector (3) always intersects with the center O of the circle; The arc detector (5) is fixedly installed on the other side of the C-arm (2) and is used to receive X-rays. The center of the arc detector (5) coincides with the center O of the circle; The X-ray source (6) is installed on the ray source position adjustment mechanism (7), located below the spherical shell-shaped object (9), and is used to generate X-rays to scan the region of interest of the spherical shell-shaped object (9); The ray source position adjustment mechanism (7) is located at the bottom of the main body frame (1) and is used to adjust the position of the X-ray source (6).

2. The system according to claim 1, wherein The sample stage (8) includes a marble platform (10). In the center of the marble platform (10), there is a hollow turntable (11) for driving the spherical shell-shaped object (9) to rotate. An adjustable bracket (12) is provided on the hollow turntable (11) for supporting the spherical shell-shaped object (9) and adjusting the position of the spherical shell-shaped object (9) so that its center is located at the center O of the circle; 3. The system according to claim 1, characterized in that The ray source position adjustment mechanism (7) includes a lifting mechanism (15), a linear module (16), an electric turntable (17), an arc track (18), a mechanism base (19) and a lower arc driving mechanism (20); The mechanism base (19) is fixed on the main body frame (1), the arc track (18) is installed on the mechanism base (19), and the lower arc driving mechanism (20) is installed on the arc track (18). The electric turntable (17) is installed on the lower arc driving mechanism (20); The lower arc driving mechanism (20) is used to drive the electric turntable (17) to swing around the center O of the circle on the arc track (18); The electric turntable (17) is provided with the linear module (16) for rotating the linear module (16); The linear module (16) is provided with the lifting mechanism (15) for controlling the movement of the lifting mechanism (15) in the horizontal plane; The X-ray source (6) is installed on the control lifting mechanism (15) for controlling the lifting of the X-ray source (6).

4. The system according to claim 3, characterized in that The center of the corresponding arc track (18) coincides with the center O.

5. The system according to claim 1, characterized in that, The central angle of the arc detector (5) is not less than 90 degrees.

6. The system according to claim 1, wherein A shielding structure is integrally provided on the outer side of the main body frame (1).

7. A method for detecting a spherical shell-shaped object based on the system described in claim 1, the steps of which include: 1) Place the spherical shell-shaped object (9) to be detected on the sample stage (8), and the center of the spherical shell-shaped object (9) is located at the center O corresponding to the C-arm (2); move the X-ray source (6) to the position of the center O; 2) Rotate the spherical shell-shaped object (9) one week. During the rotation process, scan the spherical shell-shaped object (9) with the X-ray emitted by the X-ray source (6), and collect projection data by using the arc detector (5); 3) Establish a coordinate system for recording the projection data. The origin of this coordinate system corresponds to the vertex of the spherical shell-shaped object (9). The rotation angle α ∈ [0, 2π] of the spherical shell-shaped object (9) is the abscissa of this coordinate system, and the angle β ∈ [0, π / 2] between the ray corresponding to the projection data and the horizontal plane is the ordinate of this coordinate system; for any point P on the spherical shell-shaped object (9), the coordinates of this point P in this coordinate system are (α1, β1), and through coordinate mapping, the coordinates of this point P in the intuitive projection diagram in this coordinate system are (x1, y1), and its mapping relationship is 4) Determine the region of interest on the spherical shell-shaped object (9) based on the intuitive projection diagram; 5) Adjust the center of the region of interest to the direction where the flat panel detector (3) is located; adjust the position of the flat panel detector (3) to make the center of the flat panel detector (3) close to the center of the region of interest; adjust the position of the X-ray source (6) so that the line connecting its focus and the center of the flat panel detector (3) passes through the central region of the position of the region of interest; then adjust the height of the X-ray source (6) to obtain the required magnification ratio, scan the region of interest with the X-ray emitted by the X-ray source (6), and collect projection data by using the flat panel detector (3) to obtain a high-resolution intuitive projection diagram corresponding to the region of interest.

8. A method for detecting a spherical shell-shaped object based on the system described in claim 1, the steps of which include: 1) Place the spherical shell-shaped object (9) to be detected on the sample stage (8), and the center of the spherical shell-shaped object (9) is located at the center O corresponding to the C-arm (2); move the X-ray source (6) to the position of the center O; 2) Rotate the spherical shell-shaped object (9) one week. During the rotation process, scan the spherical shell-shaped object (9) with the X-ray emitted by the X-ray source (6), and collect projection data by using the arc detector (5); 3) Establish a coordinate system for recording the projection data. The origin of this coordinate system corresponds to the vertex of the spherical shell object (9). The rotation angle α ∈ [0, 2π] of the spherical shell object (9) is the abscissa of this coordinate system, and the angle β ∈ [0, π / 2] between the ray corresponding to the projection data and the horizontal plane is the ordinate of this coordinate system. For any point P on the spherical shell object (9), the coordinates of this point P in this coordinate system are (α1, β1), and through coordinate mapping, the coordinates of this point P in the intuitive projection diagram in this coordinate system are (x1, y1), and its mapping relationship is 4) Determine the region of interest on the spherical shell object (9) based on the intuitive projection diagram; 5) Adjust the position of the X-ray source (6) so that the horizontal distance between it and the center O is r, where r is the scanning radius of the X-ray source (6). Rotate the X-ray source (6), and during the rotation, use the outgoing ray of the X-ray source (6) to scan the region of interest, and use the flat panel detector (3) to collect projection data. Obtain the three-dimensional tomographic image of the region of interest through the CL reconstruction algorithm; then determine the three-dimensional position of the defect on the spherical shell object (9) based on the three-dimensional tomographic image.

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