A high resolution vertical CT apparatus and scanning method with a helical trajectory of inclined lines

Abstract

A high-resolution vertical CT device and scanning method of oblique line scanning spiral track belong to the technical field of ray tomography. The device comprises a ray source, a flat panel detector, a data acquisition system, a mechanical motion system, a control system, a computing platform and a cabinet. The basic implementation steps of the scanning method are as follows: S1: the ray source beam translates along the axial oblique track with an angle γ, the flat panel detector is stationary, and a section of oblique track cone beam scanning is completed; S2: the measured object is relatively translated along the axis by a distance l, and the measured object is rotated by an angle interval Δθ; S3: a section of oblique scanning is continued in step S1; the spiral scanning composed of multiple oblique lines is formed reciprocally until the measured object is covered. The computing platform is provided with control system software and image reconstruction software. Compared with the previous CT, the present application not only has the advantages of simple and easy-to-control straight line scanning structure, but also can realize full coverage imaging of a flat long object and one-time imaging of multiple flat objects.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of ray tomography, and particularly relates to a high-resolution vertical CT device and scanning method of oblique scanning spiral trajectory. BACKGROUND

[0002] Computed tomography (CT) is a non-destructive testing technology for realizing internal imaging of a measured object, and is widely used in medical treatment, industrial detection, security inspection, archaeology, agriculture, geophysics and many other fields. In actual CT detection, high-resolution imaging of a large object is often required, and the traditional CT detection requires that the measured object be strictly located in the imaging field of view. If the size of the measured object is too large, the geometric magnification ratio needs to be appropriately reduced, but the imaging resolution is sacrificed. Especially when the measured object cannot be divided into small samples, such as fossils, gems, antiques and other precious objects. It has been one of the key targets in the CT imaging field to pursue a large imaging field of view and a large geometric magnification ratio (i.e., high resolution) at the same time.

[0003] In the past, the CT imaging of the expanded field of view mainly adopts the imaging geometry of the offset detector. However, on the one hand, this method can only be theoretically expanded to twice at most. On the other hand, with the expansion of the field of view and the reduction of the redundant interval, the imaging quality will be deteriorated; therefore, in actual applications, the field of view cannot be expanded to the theoretical value.

[0004] Compared with the traditional circular trajectory scanning mode, the linear scanning is easy to control the precision and engineering implementation. The patent with publication number CN104809750A proposes a simple structure, low cost, movable / portable linear scanning CT system, which adopts the scanning mode of parallel movement of the ray source and the detector in different directions, and has potential in low-cost CT. In order to realize imaging of objects beyond the field of view of the linear scanning CT, the patent with publication number CN106447740 proposes a relatively parallel linear scanning CT image reconstruction method for the region of interest, which can perform local imaging of objects beyond the field of view of the linear scanning CT, but this method cannot perform global imaging of the entire object. In order to increase the geometric magnification ratio and the imaging field of view of the cross section, the patent with publication number CN111839568A proposes a new large field of view linear scanning CT system and image reconstruction method. The system realizes linear scanning by fixing the detector and translating the X-ray source along the linear trajectory, and considering the limited length of the linear trajectory which leads to the limited angle problem of reconstruction, the system is designed to realize complete imaging of large-size objects in the transverse direction by rotating the workpiece by several angles. However, since the multiple linear scanning trajectories of the system are straight line segments in the same plane, they cannot meet the data completeness condition in cone beam CT imaging to expand the transverse field of view, and cannot realize the imaging of axial long objects. In fact, to realize higher spatial resolution, i.e. to increase the geometric magnification ratio, the cone angle will become smaller. To avoid axial truncation artifacts, the usual measure is to cut off the data outside the cone beam artifacts, which narrows the field of view of axial imaging. The above invention can also realize the scanning and imaging of long objects by performing three-dimensional reconstruction and splicing of the blocks along the axial direction of the long object; but this method not only has low scanning efficiency, but also has large registration error. In order to realize the expansion of the field of view of the spiral cone beam CT, i.e. to solve the expansion of the field of view of the transverse truncation imaging, and also to have long object imaging with axial truncation, Zou Xiaobing proposes a half-coverage spiral cone beam CT mode with transverse truncation in the research on the scanning method and reconstruction algorithm of large field of view spiral cone beam industrial CT, and further proposes a double spiral cone beam CT scanning mode, which makes the cross section of the region to be imaged be completely covered by the ray beam at each projection viewing angle. In fact, the half-coverage spiral cone beam CT imaging and double spiral cone beam CT scanning imaging studied by Zou Xiaobing are both for standard spiral trajectories, and the essence of expanding the field of view is through the offset of the detector, and when the detector offset increases, the quality of the reconstructed image deteriorates.Patent CN102004111B discloses a tilted multi-cone beam linear trajectory CT imaging method. This method involves tilting multiple cone beams at different positions, requiring multiple sets of X-ray sources and detectors. The object being examined moves linearly through all the cone beams, and the detectors collect the X-rays passing through the object from different directions. This scanning method is costly, cannot obtain complete projection data for long-axis objects, and cannot detect, accurately reconstruct, or expand the field of view for objects with very long axes. Patent CN111982939A discloses a movable multi-segment linear light source CT imaging system and method. It includes multiple movable scanning segments, each comprising a linear distributed light source array and a linear detector array. The multiple scanning segments cooperate and are parallel to each other to achieve complete data acquisition and expanded field of view imaging. Summary of the Invention

[0005] To meet the demand for full-range high-resolution CT imaging of long, ribbon-shaped objects with large aspect ratios, this invention aims to provide a high-resolution vertical CT device and scanning method with a helical scanning trajectory using oblique lines. The main feature is that it provides a non-standard helical scanning trajectory composed of multiple oblique lines, which achieves both expanded lateral field of view imaging and imaging of long objects along the axis, while inheriting the advantages of previous linear scanning CT systems, such as simple structure and easy high-precision control.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A high-resolution vertical CT device for oblique scanning spiral trajectory includes: a radiation source, a flat panel detector, a data acquisition system, a computing platform, a control system, a mechanical motion system, and a cabinet; the oblique trajectory translational scanning of the radiation source beam is achieved as follows: the workpiece to be measured is mounted on the pneumatic gripper of the mechanical motion system, the pneumatic gripper is mounted on the worktable of the mechanical motion system, after each complete oblique scan, the workpiece to be measured moves forward a distance l along its axis, and at the same time rotates by an angle Δθ along its axis under the drive of the pneumatic gripper, and the next oblique scan is performed after the movement of the workpiece to be measured stops.

[0008] The X-ray source, the workpiece under test, and the flat panel detector are all mounted on the vertical lifting guide rail of the cabinet, and the vertical distance between them can be adjusted to adjust the imaging geometric magnification ratio.

[0009] A high-resolution vertical CT device based on a diagonal scanning spiral trajectory utilizes a multi-segment diagonal spiral scanning method. This spiral scanning is a non-standard spiral scanning trajectory, and the mechanical motion formed by the mechanical motion system is as follows:

[0010] S1: The X-ray source beam moves along the oblique trajectory of the axial tilt angle γ, while the flat panel detector (3) remains stationary, thus realizing a cone beam scan of an oblique trajectory;

[0011] S2: The pneumatic gripper controls the rotation angle interval Δθ of the workpiece being measured and displaces it a distance l along its axial direction;

[0012] S3: Continue scanning a section of the oblique line trajectory from step S1, repeating this process until a spiral scanning trajectory consisting of multiple oblique lines is formed and covers the object being measured.

[0013] A high-resolution vertical CT scanning method using oblique scanning spiral trajectories can acquire complete data with a laterally expanded imaging field of view radius R1':

[0014]

[0015] Where, λ m u is half the length of the oblique translation trajectory of the X-ray source beam. m Let R be the half-length of the flat panel detector's direction, and let dod be the distance from the central axis of the rotary stage to the focal point of the X-ray source and the center of the flat panel detector, respectively.

[0016] The oblique translational scanning trajectory of the X-ray source beam in a high-resolution vertical CT scanning method with an oblique scanning spiral trajectory is as follows:

[0017]

[0018] Where, λ i Let λ be the coordinates of the focal point of the ray source on the oblique trajectory. m Let λ be half the length of the trajectory of the oblique line. i ∈[-λ m ,λ m ];θ n Let θ be the angle between the translation trajectory of the nth segment of the ray source and the positive x-axis of the fixed coordinate system. n =(n-1)·Δθ,n=1,2,...,N r ·T, where N r Let T be the number of scan revolutions, and T be the number of oblique line trajectory segments required for one scan revolution. Δθ is determined by the following relationship: Δθ = 2arctan(u m / dod), and thus T can be determined by the following relationship: T=ceil(2π / Δθ), ceil(·) means rounding up; z(λ i Let (n) be the coordinates of the X-ray source beam on the z-axis of the fixed coordinate system, and the calculation formula is:

[0019]

[0020] Where p is the pitch, satisfying p = 2Z m / Nr Z m The z-axis half-length of the helical scan trajectory (excluding redundant portions intersecting adjacent oblique scan trajectories) must satisfy 2Z. m ≥Z body Z body l is the z-axis length of the object being measured; p Let be the total length along the z-axis of the helical scanning trajectory.

[0021]

[0022] The formula for calculating the axial inclination angle γ of the oblique trajectory is:

[0023]

[0024] Let be the rotation matrix of the translation trajectory of the nth segment of the ray source's oblique line.

[0025]

[0026] The X-ray source emits X-rays under the command and control of the control system. The flat panel detector receives the X-rays penetrating the workpiece and converts them into electrical signals. The data acquisition system collects and transmits these electrical signals, which are then processed and displayed by the computing platform. The control system includes control software and control hardware. The control software is deployed within the computing platform. The control software, along with communication interfaces and protocols, controls parameters such as the tube voltage, tube current, and exposure time of the X-ray source. Combined with the control hardware, communication interfaces, and protocols, it drives the mechanical motion system to achieve multi-axis precision motion. It also uses high-speed communication interfaces and protocols to send control commands to the data acquisition system and enable data uplink and downlink. The data acquisition system acquires, encodes, and transmits the projected images from the flat panel detector at high speed. The acquired projected images are then transmitted in a specific format and stored on the computing platform's hard drive or memory for image reconstruction by the image reconstruction software deployed within the computing platform.

[0027] The mechanical motion system is the core of this system. It is responsible for the oblique translation of the X-ray source, adjusting the axial tilt angle γ of the oblique translation track of the X-ray source, adjusting the vertical position of the flat panel detector, and adjusting the rotation, vertical position, and horizontal position of the workpiece being measured. Through the combination of mechanical motion, it realizes the helical scanning of multiple oblique lines.

[0028] The distance l by which the mechanical motion system controls the axial forward displacement of the workpiece being measured is determined by l = p / T.

[0029] The beneficial effects of this invention are as follows:

[0030] (1) The high-resolution vertical CT device and scanning method with oblique scanning spiral trajectory provided by the present invention, compared with relative straight scanning CT, planar multi-segment straight scanning CT and standard spiral scanning CT, can not only expand the horizontal field of view to image large objects, but also expand the axial field of view to image long objects.

[0031] (2) Compared with standard spiral field-expanding CT systems such as half-coverage spiral scanning and dual spiral scanning, the high-resolution vertical CT device and scanning method with oblique scanning spiral trajectory provided by the present invention have the advantages of simple scanning method and easy high-precision control and implementation due to the presence of some characteristics of linear scanning. It can achieve adjustable expansion of the lateral field of view by adjusting the length of the oblique translation trajectory of the X-ray source; it can achieve adjustable axial imaging length by adjusting parameters such as the axial tilt angle, length of the oblique translation trajectory of the X-ray source, and number of scans; it can conveniently control the number of sampling points of the oblique translation of the X-ray source beam to increase the number of projections and improve imaging quality.

[0032] (3) The high-resolution vertical CT device and scanning method for oblique scanning spiral trajectory provided by the present invention are more suitable for full-coverage detection of flat or strip-shaped workpieces compared with traditional CT structures, while minimizing the working volume and simplifying the mechanical structure.

[0033] (4) The spiral scanning method with multiple oblique lines provided by the present invention has the advantages of high X-ray utilization efficiency and high scanning efficiency, and meets the data completeness requirements for three-dimensional accurate CT image reconstruction. Attached Figure Description

[0034] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0035] Figure 1 This is a system architecture diagram of the present invention;

[0036] Figure 2 This is a schematic diagram of cone-beam scanning geometry for multiple horizontal straight lines in a plane, presented for the purpose of illustrating the advantages of this invention;

[0037] Figures 3(a)-(c) show the structural diagrams of the equipment of the present invention from different perspectives;

[0038] Figures 4(a)-(b) are schematic diagrams of the oblique cone beam scanning process of the device of the present invention;

[0039] Figure 5 This is a schematic diagram of the mechanical movement of the worktable (7.3) during the full-coverage scanning process of the device of the present invention;

[0040] Figures 6(a)-(c) show schematic diagrams of the spiral scanning trajectory of the present invention under specific geometric parameters, with 3 turns and 10 segments of oblique lines combined in each turn;

[0041] Figure 7 The reconstructed image is shown using a custom phantom and the SIRT iterative reconstruction algorithm in a numerical experiment. Detailed Implementation

[0042] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings and examples.

[0043] A high-resolution vertical CT device for oblique scanning spiral trajectories, its system architecture diagram is as follows: Figure 1 As shown, it mainly includes: X-ray source 1, flat panel detector 3, data acquisition system 4, computing platform 5, control system 6, mechanical motion system 7, and cabinet 8;

[0044] The mechanical motion of the X-ray source 1 beam during the translational scanning of the oblique trajectory spiral trajectory in a high-resolution vertical CT scanning method is as follows:

[0045] 1) Before testing, the workpiece 2 to be tested is clamped and fixed on the working surface by pneumatic jaws 7.4;

[0046] 2) During the inspection, the X-ray source 1 translates along the linear motion module 7.1 to complete a section of oblique scanning. Then, the pneumatic gripper 7.4 extends a distance l along its axis, and correspondingly, the pneumatic gripper 7.5 retracts a distance l along its axis, causing the workpiece 2 to move forward a distance l along its axis. Then, the pneumatic grippers 7.4-7.5 drive the workpiece 2 to rotate around the axis by an angle interval Δθ. After the movement is completed, the X-ray source 1 continues to perform oblique scanning. This process is repeated until the workpiece 2 gradually passes through the entire scanning area, completing the CT scan of the entire workpiece 2.

[0047] Under the command and control of the control system 6, the X-ray source 1 emits X-rays. The flat panel detector 3 receives the X-rays penetrating the workpiece 2 and converts them into electrical signals. The data acquisition system 4 acquires and transmits these electrical signals, which are then processed and displayed by the computing platform 5. The control system 6 includes control software and control hardware. The control software is deployed within the computing platform 5. The control software of the computing platform 5, in conjunction with a communication interface and protocol, can control parameters such as the tube voltage, tube current, and exposure time of the X-ray source 1. In conjunction with the control hardware, communication interface, and protocol, it can drive the mechanical motion system 7 to achieve multi-axis precision motion. It also uses a high-speed communication interface and protocol to issue control commands to the data acquisition system 4 and achieve data uplink and downlink. The data acquisition system 4 performs high-speed acquisition, encoding, and transmission of the projected images from the flat panel detector 3. The data acquisition system 4 transmits the acquired projected images in a specific format and stores them on the hard disk or in the memory of the computing platform 5 for image reconstruction by the image reconstruction software deployed within the computing platform 5.

[0048] The mechanical motion system 7 is the core of this system. It is responsible for the oblique translation of the X-ray source 1, adjusting the axial tilt angle γ of the oblique translation track of the X-ray source 1, adjusting the vertical position of the flat plate detector 3, and adjusting the rotation, vertical position and horizontal position of the workpiece 2 being measured. It achieves helical scanning of multiple oblique lines through the combination of mechanical motion.

[0049] A high-resolution vertical CT scanning method using a multi-segment oblique spiral trajectory employs a non-standard spiral scanning trajectory. The mechanical motion formed by the mechanical motion system 7 is as follows:

[0050] S1: The beam from X-ray source 1 is translated along the oblique trajectory of the axial tilt angle γ, while the flat panel detector 3 remains stationary, thus achieving a cone beam scan of an oblique trajectory.

[0051] S2: The pneumatic gripper controls the rotation angle interval Δθ of the workpiece 2 being measured, and displaces it a distance l along the workpiece axis;

[0052] S3: Continue scanning a section of the oblique line trajectory from step S1, repeating this process until a spiral scanning trajectory consisting of multiple oblique lines is formed and covers the object being measured 2.

[0053] To facilitate the explanation of the features of the present invention, Figure 2 The diagram shows the scanning geometry of a "novel large field-of-view linear scanning CT system" proposed in patent CN111839568A. If used... Figure 2The CT system shown requires high-resolution imaging of large objects. To achieve a large geometric magnification ratio, the object 2 needs to be brought close to the X-ray source 1. This means the distance R from the central axis of the rotating stage to the focal point of the X-ray source 1 decreases, the distance dod from the central axis of the rotating stage to the center of the flat panel detector 3 increases, while the distance sdd from the focal point of the X-ray source 1 to the center of the flat panel detector 3 remains constant. Since sdd = dod + R, the width Z of the intersection point between the reconstructed cylindrical region and the X-ray beam is determined. rec Narrowing, its calculation formula is:

[0054] Z rec =2(R-R1)v m / sdd,

[0055] Among them, v m R1 is the half-length of the three columns of the flat panel detector. Figure 2 The radius of the lateral expansion of the imaging field of view of the CT system shown can acquire complete two-dimensional data in the central plane, and its calculation formula is as follows:

[0056]

[0057] Where, λ m for Figure 2 The half-length of the linear scan trajectory in the CT system shown. The width Z of the intersection point between the reconstructed cylindrical region and the X-ray beam. rec The area that can be reconstructed by the actual system when performing 3D scanning of large objects becomes narrower along the axis, meaning that only objects that are very thin along the axis can be reconstructed, while severe cone-beam artifacts appear in the reconstruction area that deviates from the intersection point.

[0058] Figures 3(a)-(c) show the structural diagrams of the equipment of the present invention from different perspectives. In Figure 3(a), the mechanical motion system 7 includes: a linear motion module 7.1 for the X-ray source, a rotary table 7.2 for the X-ray source, a worktable 7.3 and the pneumatic grippers 7.4-7.5 supported by it, and a flat panel detector bracket 7.6. The mechanical motion system 7 is installed on the vertical lifting guide rail of the cabinet 8.

[0059] The mechanical motion system 7 controls the workpiece 2 to move forward axially by a distance l, which is determined by l = p / T. The X-ray source 1, the workpiece 2, and the flat panel detector 3 are all mounted on the vertical lifting guide rail of the cabinet 8, and the vertical distance between them can be adjusted to adjust the imaging geometric magnification ratio.

[0060] To facilitate the explanation of how the mechanical motion is implemented, the present invention is comprehensively implemented in terms of mechanical structure. It should be noted that the present invention is not limited to the specific embodiments described above; the numerous degrees of freedom are only provided for ease of explanation. In practice, any form of mechanical motion can be used, thereby reducing the degrees of freedom, hardware costs, manufacturing and assembly difficulties, and cumulative errors.

[0061] The specific implementation of the mechanical motion system 7 of the present invention is as follows:

[0062] The X-ray source linear motion module 7.1 is mounted on the X-ray source rotary table 7.2 on the cabinet 8. The X-ray source 1 is mounted on the slider of the X-ray source linear motion module 7.1. The workpiece 2 to be measured is clamped on the worktable 7.3 by pneumatic grippers 7.4-7.5. The flat panel detector is mounted on the flat panel detector bracket 7.6. The X-ray source rotary table 7.2, the worktable 7.3, and the flat panel detector bracket 7.6 are all mounted on the vertical lifting guide rail of the cabinet 8, and the vertical distance between them can be adjusted to adjust the imaging geometric magnification ratio. The X-ray source 1 can be precisely controlled by the X-ray source linear motion module 7.1 to perform oblique translational movement a.2. At the same time, the X-ray source 1 and the linear motion module 7.1 can be rotated as a whole by the X-ray source rotary table 7.2 to generate a control axial tilt angle γ.

[0063] During the spiral scanning process, the mechanical motion of the workpiece 2 being measured, as described in this invention, is as follows: Figure 5 As shown, the pneumatic grippers 7.4-7.5 can perform high-precision rotation (b.1) and extension (b.2), while the X-ray source performs oblique translational movement (a.2) on the linear motion module 7.1. Referring to Figure 3(a), after the X-ray source rotary table 7.2, worktable 7.3, and flat panel detector bracket 7.6 are adjusted to suitable positions, they are fixed in their positions by locking devices. The bottom linear motion module 7.1 and the X-ray source rotary table 7.2 can realize the horizontal position movement (a.2) and axial rotation (a.1) of the X-ray source. The pneumatic grippers 7.4-7.5 are mounted on the worktable 7.3, and through extension and retraction, they drive the workpiece 2 to perform relative displacement (b.2) along its axial direction; through axial rotation (b.1), they drive the workpiece 2 to generate an axial tilt angle Δθ.

[0064] A high-resolution vertical CT scanning method using a diagonal scanning spiral trajectory can acquire complete data with a laterally expanded imaging field of view radius R1' of:

[0065]

[0066] Where, λ m u is the half-length of the oblique translation trajectory of the beam from X-ray source 1. m Let R be the half-length of the row direction of the flat panel detector 3, and let dod be the distance from the central axis of the rotary stage to the focal point of the X-ray source 1 and the center of the flat panel detector 3, respectively.

[0067] The oblique translational scanning trajectory of the X-ray source 1 beam in a high-resolution vertical CT scanning method with an oblique scanning spiral trajectory is as follows:

[0068]

[0069] Where, λi Let λ be the coordinates of the focus of ray source 1 on the oblique trajectory. m Let λ be half the length of the trajectory of the oblique line. i ∈[-λ m ,λ m ];θ n Let θ be the angle between the translation trajectory of the nth segment of the ray source and the positive x-axis of the fixed coordinate system. n =(n-1)·Δθ,n=1,2,...,N r ·T, where N r Let T be the number of scan revolutions, and T be the number of oblique line trajectory segments required for one scan revolution. Δθ is determined by the following relationship: Δθ = 2arctan(u m / dod), and thus T can be determined by the following relationship: T=ceil(2π / Δθ), ceil(·) means rounding up; z(λ i Let (n) be the coordinates of the beam from X-ray source 1 on the z-axis of the fixed coordinate system, and the calculation formula is:

[0070]

[0071] Where p is the pitch, satisfying p = 2Z m / N r Z m The z-axis half-length of the helical scan trajectory (excluding redundant portions intersecting adjacent oblique scan trajectories) must satisfy 2Z. m ≥Z body Z body l is the z-axis length of the object being measured 2; p Let be the total length along the z-axis of the helical scanning trajectory.

[0072]

[0073] The formula for calculating the axial inclination angle γ of the oblique trajectory is:

[0074]

[0075] Let be the rotation matrix of the translation trajectory of the nth segment of the ray source's oblique line.

[0076]

[0077] It should be noted that the form of the workpiece 2 to be tested by the device of the present invention can be a workpiece with a large aspect ratio, such as a columnar or flat shape, or a workpiece strip packaged from multiple flat workpieces, such as chip tape.

[0078] The non-standard spiral scanning trajectory of the present invention with multiple oblique line combinations was simulated. The scanning parameters are shown in Table 1. The axonometric view, top view and side view of the spiral scanning trajectory with 3 turns and 10 oblique line combinations per turn are shown in Figures 6(a)-(c).

[0079] To address the multi-segment oblique line combination spiral scanning field-expanding CT system of this invention, the present invention provides the SIRT iterative image reconstruction algorithm. To verify the embodiments of this invention, based on the simulation scanning parameters described in Table 1, a rod-shaped phantom with a custom radial radius R1' and an axial height of 18mm was used as the object under test for multi-segment oblique line combination spiral scanning to obtain cone-beam projection data. Finally, the SIRT iterative image reconstruction algorithm was used for reconstruction, and the reconstruction results are as follows. Figure 7 As shown.

[0080] Table 1. Simulation Scan Parameters

[0081]

[0082] This invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other modifications based on the teachings of this invention without departing from the spirit and scope of the claims. All of these modifications are within the protection scope of this invention.

Claims

1. A high-resolution vertical CT scanning method for oblique scanning spiral trajectories, the method using a high-resolution vertical CT device for oblique scanning spiral trajectories, the device comprising: The system comprises: a radiation source (1), a flat panel detector (3), a data acquisition system (4), a computing platform (5), a control system (6), a mechanical motion system (7), and a cabinet (8); the mechanical motion system (7) includes: a radiation source linear motion module (7.1), a radiation source rotary table (7.2), a worktable (7.3) and the pneumatic grippers (7.4)-(7.5) it carries, and a flat panel detector bracket (7.6); characterized in that: The X-ray source (1) is connected to the X-ray source linear motion module (7.1) in the mechanical motion system (7) and is assembled together on the X-ray source rotary table (7.2) in the mechanical motion system (7). The X-ray source (1) and the linear motion module (7.1) can be rotated as a whole by the X-ray source rotary table (7.2) to generate a control axial tilt angle γ, thereby realizing the linear translation of the X-ray source (1) at angle γ. The X-ray source (1), the workpiece under test (2), and the flat panel detector (3) are all installed on the vertical lifting guide rail of the cabinet (8) and the vertical distance between them can be adjusted to realize the adjustment of the imaging geometric magnification ratio. The non-standard multi-segment oblique spiral scanning trajectory of the workpiece (2) is implemented as follows: the workpiece (2) is mounted on the pneumatic jaws (7.4-7.5) of the mechanical motion system (7), and the pneumatic jaws (7.4-7.5) are mounted on the worktable (7.3) of the mechanical motion system (7). Under the condition that the workpiece (2) is kept stationary, the X-ray source linear motion module (7.1) and the X-ray source rotary table (7.2) of the mechanical motion system (7) drive the X-ray source to perform oblique motion and perform one oblique scan. After completing one oblique scan, the workpiece (2) moves forward a distance l along its axis and rotates by an angle Δθ along its axis under the drive of the pneumatic jaws (7.4-7.5). After the movement of the workpiece (2) stops, the next oblique scan is performed.

2. According to claim 1, a high-resolution vertical CT scanning method for oblique scanning spiral trajectories, based on this method, the spiral scan composed of multiple oblique lines is a non-standard spiral scanning trajectory, and the mechanical motion form formed by the mechanical motion system (7) is as follows: S1: The beam of the X-ray source (1) is translated along the oblique trajectory of the axial tilt angle γ, while the flat panel detector (3) remains stationary, thus realizing a cone beam scan of an oblique trajectory; S2: The pneumatic gripper (7.4-7.5) controls the rotation angle interval Δθ of the workpiece (2) to be measured, and moves a distance l along the workpiece axis. After moving into place, the workpiece (2) stops moving. S3: Continue scanning a section of the oblique trajectory from step S1, repeating this process until a spiral scanning trajectory consisting of multiple oblique lines is formed and covers the workpiece (2) being measured. The high-resolution vertical CT scanning method using oblique scanning spiral trajectories can acquire complete data with a laterally expanded imaging field of view radius R1′: in, λ m u is half the length of the oblique translation trajectory of the beam from the X-ray source (1). m R is the half length of the row direction of the flat panel detector (3), and R and dod are the distances from the central axis of the rotary stage to the focal point of the X-ray source (1) and the center of the flat panel detector (3), respectively. The oblique translational scanning trajectory of the X-ray source (1) beam in the high-resolution vertical CT scanning method with oblique scanning spiral trajectory is as follows: Where, λ i Let λ be the coordinates of the focus of the ray source (1) on the oblique trajectory. i ∈[-λ m ,λ m ];θ n Let θ be the angle between the translation trajectory of the nth segment of the ray source and the positive x-axis of the fixed coordinate system. n =(n-1)·Δθ,n=1,2,...,N r ·T, where N r Let T be the number of scan revolutions, and T be the number of oblique line trajectory segments required for one scan revolution. Δθ is determined by the following relationship: Δθ = 2arctan(u m / dod), and thus T can be determined by the following relationship: T=ceil(2π / Δθ), ceil(·) means rounding up; z(λ i n) is the coordinate of the beam of the X-ray source (1) on the z-axis of the fixed coordinate system, and the calculation formula is: Where p is the pitch, satisfying p = 2Z m / N r Z m The spiral scan trajectory is the z-axis half-length, and the spiral scan trajectory does not contain redundant portions intersecting adjacent oblique scan trajectories, and must satisfy 2Z. m ≥Z body Z body l is the z-axis length of the object being measured; p Let be the total length along the z-axis of the helical scanning trajectory. The formula for calculating the axial inclination angle γ of the oblique trajectory is: Let be the rotation matrix of the translation trajectory of the nth segment of the ray source's oblique line.

3. The high-resolution vertical CT scanning method for oblique scanning spiral trajectories according to claim 2, characterized in that, The axial displacement distance l of the workpiece (2) being measured is determined by l = p / T.

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