High-resolution X-ray tomography system and method

Abstract

The invention relates to the technical field of X-ray tomography, and discloses a high-resolution X-ray tomography system and method.According to the system, an X-ray source and a piezoelectric ceramic type mechanical grating form a coding transmitting end, a precise displacement control system is combined to adjust the grating distance, and full-band scanning of X-ray spatial frequency is achieved; the synchronous control unit coordinates three-step phase shift and inclined rotary scanning of the grating to obtain multi-phase projection data, and demodulates and separates a direct-current component and an alternating-current component through a three-step phase shift method; three-dimensional structures under different frequencies are reconstructed based on an FDK algorithm, optimal slices of all layers are screened and fused layer by layer through comprehensive evaluation of indexes such as a modulation transfer function, full width at half maximum and a peak signal-to-noise ratio, and high-resolution three-dimensional reconstruction of the internal structure of the circuit board is achieved; according to the scheme, through hardware coding modulation and multi-frequency data fusion, beam hardening and scattering noise are effectively restrained, the image resolution and the detection precision are improved, and the method is suitable for nondestructive detection of complex structures such as electronic circuit boards.

Description

Technical Field

[0001] This invention relates to the field of X-ray tomography technology, and in particular to a high-resolution X-ray tomography system and method. Background Technology

[0002] X-ray tomography is widely used in medical diagnosis, industrial inspection, geological exploration, and other fields. Especially in the non-destructive testing of electronic circuit boards, multi-angle scanning and image reconstruction can achieve quality control of their internal three-dimensional structure. However, high-impedance materials in electronic circuit boards (such as copper traces and aluminum casings) can cause beam hardening and scattering noise to interfere with each other, resulting in serious problems such as stripe artifacts and blurred / distorted edges in the images. This not only reduces the accuracy of defect identification but also limits the accuracy of full-scale analysis of the circuit board. Current technologies mainly deal with artifacts through hardware improvements (such as optimizing X-ray sources or detectors) and algorithm processing. However, hardware upgrades are costly and reduce system flexibility, while algorithm processing can cause high-frequency signal loss, resulting in reduced contrast in the reconstructed image and making it difficult to balance noise suppression and detail preservation.

[0003] The limitations of existing hardware improvements and algorithm processing urgently necessitate a high-resolution imaging scheme that can effectively suppress noise interference while preserving structural details. Addressing the issues of image degradation, cost-accuracy contradictions, and other problems faced by traditional methods when processing complex circuit boards, this invention proposes an X-ray tomography system and method based on grating-coded modulation. Through an active spatial light field modulation mechanism and multi-spatial frequency fusion technology, it achieves precise suppression of artifacts and high-resolution reconstruction of different structural levels, breaking through the bottleneck of existing technologies in balancing imaging quality and system cost. Summary of the Invention

[0004] The main objective of this invention is to provide a high-resolution X-ray tomography system and method that can effectively solve the problems in the background art.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A high-resolution X-ray tomography system, comprising: Grating-encoded emission unit: It consists of an X-ray source and a piezoelectric ceramic mechanical grating. The piezoelectric ceramic mechanical grating is located at the front end of the X-ray source's output port. The two together form a grating-encoded X-ray emission end, which is used to emit X-rays modulated by spatial frequency. Planar detector: positioned opposite the grating-encoded transmitter, used to acquire X-ray projection data passing through the circuit board under test; Precision displacement control system: Includes a lead screw and guide rail, servo motor, encoder, and controller. It employs a fully closed-loop control architecture to adjust the distance between the X-ray source and the piezoelectric ceramic mechanical grating, achieving precise control of the grating-encoded X-ray spatial frequency. The distance... With spatial frequency satisfy: , The initial distance, The reference spatial frequency; Synchronization control unit: Used to coordinate the phase shift of the piezoelectric ceramic actuator on the mechanical grating, the angle control of the servo motor on the rotary platform, and the planar detector. Data acquisition enables simultaneous execution of tilted 360° rotation scanning and three-step phase shifting; Image data processing unit: used to perform three-step phase-shift demodulation, multi-spatial-frequency three-dimensional reconstruction and image fusion on the projection data, and output high-resolution three-dimensional tomographic images.

[0006] Preferably, the synchronization control unit uses a closed-loop feedback mechanism to control the mechanical grating to complete three-step phase shifts at each scanning angle, thereby acquiring projection data for different phases. The projection data expression is: , , , in, The DC component, For the purpose of exchanging quantities, The initial phase is given by the formula, where the superscript d indicates the spacing between the X-ray source and the piezoelectric ceramic mechanical grating 3. A specific value / image at a given time; by adjusting this spacing, image data and reconstruction results at different spatial frequencies can be obtained.

[0007] Preferably, the image data processing unit includes: The demodulation unit uses a three-step phase-shift method to calculate the DC and AC components. The reconstruction and fusion unit uses the FDK algorithm to reconstruct the three-dimensional structure from projection data of different spatial frequencies. It comprehensively evaluates the modulation transfer function (MTF), full width at half maximum (FWHM), and peak signal-to-noise ratio (PSNR) to select the optimal reconstruction layer for each spatial frequency and fuses them layer by layer.

[0008] A high-resolution X-ray tomography method, applicable to the aforementioned high-resolution X-ray tomography system, includes the following steps: Step S1: Construction of the grating-coded X-ray tomography system; The circuit board under test is placed between the grating-encoded X-ray emitting end and the planar detector to complete the system hardware connection and synchronous control parameter configuration, so that the planar detector, X-ray source and piezoelectric ceramic mechanical grating can be synchronously controlled. Step S2: Control the distance between the grating and the X-ray source ; The distance between the X-ray source and the piezoelectric ceramic mechanical grating is adjusted sequentially by a precision displacement control system, traversing N preset discrete spatial frequency points. At each frequency point, subsequent data acquisition and processing are performed to complete a full-band scan from low to high frequencies. The correspondence between the distance and the spatial frequency is as follows: ; Step S3: Control the grating phase shift and data acquisition ; The system synchronously controls the piezoelectric ceramic actuator to adjust the phase of the mechanical grating according to a predetermined sequence. A three-step phase shift is performed, and a servo motor controls a rotating platform to drive the circuit board under test to perform a tilted 360° rotational scan, acquiring multi-angle projection data under different phases. ; Step S4: Three-step phase-shifting image demodulation ; The three-step phase-shifting projection data acquired at various angles were processed using the three-step phase-shifting method. Image demodulation is performed using the formula and Calculate the DC and AC components at each projection angle, and sequentially obtain the demodulation results at N discrete frequency points to form a DC component group. With the communication component group DC component The imaging results, corresponding to traditional grating-free modulation, include structural artifacts and edge blur noise, and AC components. After grating coding modulation, noise is suppressed while high-frequency information is preserved; In step S2, the spatial frequency distribution of the grating-encoded X-rays is controlled, and the demodulation results at N discrete frequency points are obtained sequentially to obtain the DC component group. and communication component groups ; Step S5: High-resolution 3D structure reconstruction by multi-spatial frequency fusion; For projection data at different spatial frequencies, the Feldkamp, ​​Davis, and Kress algorithm is used to reconstruct the internal three-dimensional structure. Combined with a resolution evaluation algorithm, the MTF, FWHM, and PSNR indices are used to quantitatively evaluate the reconstructed image and select the optimal reconstruction layer at each spatial frequency. High MTF, low FWHM, and high PSNR generally indicate high image contrast and good detail preservation. To unify the quantitative indicators, normalization is first performed. For MTF and PSNR, forward normalization is used, while FWHM is reverse normalized to ensure that a larger value represents better quality. Weighting coefficients are set for comprehensive evaluation, specifically: MTF weight is 0.5, FWHM weight is 0.3, and PSNR weight is 0.2. The optimal reconstruction slices of different frequency bands are stacked and fused in a hierarchical manner to build a three-dimensional internal structure layer by layer, thereby achieving high-resolution three-dimensional reconstruction. Low-frequency modulation enhances the contrast of deep structures, while high-frequency modulation improves the resolution of surface and near-surface details. This method ensures that each reconstruction layer uses the clearest image data at the corresponding spatial frequency, thereby achieving full-depth preservation of high-resolution details during volume reconstruction and ultimately obtaining a three-dimensional high-resolution X-ray tomographic image with clear structure and rich details.

[0009] Furthermore, in step S2, the precision displacement control system provides real-time feedback of the spacing via an encoder. This enables micrometer-level adjustment of the distance between the X-ray source and the piezoelectric ceramic mechanical grating, ensuring continuous control across different spatial frequency bands.

[0010] Furthermore, in step S3, the system controller can coordinate the rotational scanning and grating phase shift in real time to ensure that the two work synchronously. Specifically, the rotational platform is precisely controlled by a servo motor, while the piezoelectric ceramic driver achieves micron-level displacement through voltage adjustment, thereby precisely controlling the grating phase shift. After each scanning angle is completed, the system automatically adjusts the grating position based on closed-loop feedback to ensure the phase shift accuracy and data acquisition consistency.

[0011] Furthermore, in step S4, the modulation of the grating encoding spatial frequency has a characteristic correspondence with the penetration depth resolution capability. Specifically, the low-frequency modulation mode can effectively enhance the imaging contrast of deep structures, while the high-frequency modulation mode can significantly improve the detail resolution capability of surface and near-surface structures.

[0012] Furthermore, in step S4, the calculated DC component Compared to traditional X-ray tomography without grating-coded modulation, the images contain noise interference such as structural artifacts and blurred edges, while the AC component... Through grating coding modulation, key high-frequency information can be preserved while suppressing this type of noise interference.

[0013] Furthermore, in step S5, after a comprehensive evaluation based on image quality indicators, the system fuses the optimal reconstructed slices of different frequency bands at different levels to achieve full-depth high-resolution detail preservation, and finally obtains a three-dimensional X-ray tomographic image with clear structure and rich details.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. Effectively suppresses imaging artifacts and improves image resolution. This invention actively modulates the X-ray spatial light field through grating coding modulation technology and uses a three-step phase shift method to separate the DC component and AC component, effectively suppressing interference such as beam hardening effect and scattering noise-induced stripe artifacts and edge blurring, thus significantly improving the spatial resolution and signal-to-noise ratio of the reconstructed image, especially significantly improving the detail recognition accuracy of high impedance material areas in circuit boards.

[0015] 2. Precisely control spatial frequency to achieve multi-scale imaging. The precision displacement control system dynamically controls the spatial frequency distribution of grating-encoded X-rays by adjusting the distance between the grating and the X-ray source at the micrometer level. Low-frequency modulation enhances the imaging contrast of the deep structure of the circuit board, while high-frequency modulation improves the detail resolution of the surface and near-surface structures. This enables multi-scale, high-resolution 3D reconstruction of different layers of the circuit board, meeting the inspection requirements for full-depth detail preservation.

[0016] 3. Hardware and algorithm co-optimization to reduce system costs. Compared to traditional hardware improvement solutions, this invention improves imaging quality through the synergistic effect of grating coding modulation technology and multi-frequency image fusion algorithm without relying on high-cost X-ray source or detector upgrades. It avoids the problem of reduced system flexibility caused by hardware upgrades, significantly reduces equipment costs and maintenance complexity, and balances detection accuracy and efficiency.

[0017] 4. Fully closed-loop synchronous control ensures data acquisition accuracy. The system achieves synchronous collaboration of grating phase shift, rotation scanning and data acquisition through a fully closed-loop control architecture. Based on the precise control of servo motors and piezoelectric ceramic drivers, it ensures the consistency of phase shift accuracy and projection data at each scanning angle, avoids image distortion caused by mechanical errors, and improves the reliability of data acquisition and the stability of reconstruction results.

[0018] 5. Layered fusion reconstruction to achieve full-depth detail preservation. By comprehensively evaluating multiple indicators such as modulation transfer function, full width at half maximum (FWHM), and peak signal-to-noise ratio (PSNR), the optimal reconstructed slices at each spatial frequency are selected and fused layer by layer. This ensures that each reconstructed layer uses the clearest image data at the corresponding frequency, ultimately obtaining a clear and detailed three-dimensional high-resolution X-ray tomographic image, thus comprehensively improving the detection accuracy of the internal three-dimensional structure of the circuit board. Attached Figure Description

[0019] Figure 1 This is a flowchart of the hardware system control and software data processing provided by the present invention. Figure 2 This is a schematic diagram of the high-resolution X-ray tomography system based on grating-coded modulation technology provided by the present invention; Figure 3 This is a schematic diagram showing the correspondence between the grating-X-ray source distance dynamic control mechanism and the grating spatial frequency distribution provided by the present invention; Figure 4 This is a high-resolution reconstruction diagram of the multi-layer structure of a circuit board using the multi-spatial frequency fusion technology provided by the present invention. Figure 5 This is an enhanced image of the projected images obtained by the high-resolution X-ray tomography method provided by the present invention at different scanning angles.

[0020] In the figure: 1. Planar detector; 2. X-ray source; 3. Piezoelectric ceramic mechanical grating; 4. Circuit board under test. Detailed Implementation

[0021] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0022] like Figures 1-5 As shown, a high-resolution X-ray tomography system and method are disclosed, wherein the high-resolution X-ray tomography method includes the following steps: Step S1: Construction of the grating-coded X-ray tomography system. This grating-coded X-ray tomography system is a high-resolution X-ray tomography system of the present invention. The high-resolution X-ray tomography system includes a grating-coded emission unit, a planar detector 1, a precision displacement control system, a synchronization control unit, and an image data processing unit. The circuit board under test 4 is placed between the grating-encoded X-ray emitting end and the planar detector 1 to complete the system hardware connection and synchronous control parameter configuration, so that the planar detector 1, X-ray source 2 and piezoelectric ceramic mechanical grating 3 can be synchronously controlled. The grating-encoded emission unit consists of an X-ray source 2 and a piezoelectric ceramic mechanical grating 3. The piezoelectric ceramic mechanical grating 3 is located at the front end of the light outlet of the X-ray source 2. The two together form a grating-encoded X-ray emission end, which is used to emit X-rays modulated by spatial frequency. Planar detector 1: It is set opposite to the grating-encoded transmitter and is used to collect X-ray projection data passing through the circuit board 4 under test; Precision displacement control system: including lead screw and guide rail, servo motor, encoder and controller, adopting a fully closed-loop control architecture, used to adjust the distance between X-ray source 2 and piezoelectric ceramic mechanical grating 3, to achieve precise control of the spatial frequency of grating-encoded X-rays, wherein the distance... With spatial frequency satisfy: , The initial distance, The reference spatial frequency; Synchronization control unit: used to coordinate the phase shift of the piezoelectric ceramic actuator on the mechanical grating, the angle control of the servo motor on the rotary platform, and the planar detector 1. Data acquisition enables simultaneous execution of tilted 360° rotation scanning and three-step phase shifting; Image data processing unit: used to perform three-step phase-shift demodulation, multi-spatial-frequency three-dimensional reconstruction and image fusion on the projection data, and output high-resolution three-dimensional tomographic images; The image data processing unit includes: a demodulation unit and a demodulation module; The demodulation unit uses a three-step phase-shift method to calculate the DC and AC components. The reconstruction and fusion unit uses the FDK algorithm to reconstruct the three-dimensional structure from projection data of different spatial frequencies. It comprehensively evaluates the modulation transfer function (MTF), full width at half maximum (FWHM), and peak signal-to-noise ratio (PSNR) to select the optimal reconstruction layer for each spatial frequency and fuses them layer by layer.

[0023] Step S2: Control the distance between the grating and the X-ray source 2 The distance between the X-ray source 2 and the piezoelectric ceramic mechanical grating 3 is adjusted sequentially by a precision displacement control system, traversing N preset discrete spatial frequency points. At each frequency point, subsequent data acquisition and processing are performed to complete a full-band scan from low to high frequencies. The correspondence between the distance and the spatial frequency is as follows: ; In step S2, the precision displacement control system provides real-time feedback of the spacing via the encoder. This enables micron-level adjustment of the distance between the X-ray source 2 and the piezoelectric ceramic mechanical grating 3, ensuring continuous control across different spatial frequency bands.

[0024] Step S3: Control the grating phase shift and data acquisition The system synchronously controls the piezoelectric ceramic actuator to adjust the phase of the mechanical grating according to a predetermined sequence. A three-step phase shift is performed, and simultaneously, a servo motor controls a rotating platform to drive the circuit board under test 4 to perform a tilted 360° rotational scan, acquiring multi-angle projection data under different phases. ; The synchronous control unit uses a closed-loop feedback mechanism to control the mechanical grating to complete three-step phase shifts at each scanning angle, thereby acquiring projection data of different phases. The projection data expression is: , , , in, The DC component, For the purpose of exchanging quantities, The initial phase is given by the formula, where the superscript d indicates the spacing between the parameters at the X-ray source 2 and the piezoelectric ceramic mechanical grating 3. A specific value / image at a given time; by adjusting this spacing, image data and reconstruction results at different spatial frequencies can be obtained; The system controller can coordinate the rotation scanning and grating phase shift in real time to ensure that the two work synchronously. Specifically, the rotation platform is precisely controlled by a servo motor, while the piezoelectric ceramic driver achieves micron-level displacement through voltage regulation, thereby precisely controlling the grating phase shift. After each scanning angle is completed, the system automatically adjusts the grating position based on closed-loop feedback to ensure phase shift accuracy and data acquisition consistency.

[0025] Step S4: Three-step phase-shifting image demodulation The three-step phase-shifting projection data acquired at various angles were processed using the three-step phase-shifting method. Image demodulation is performed using the formula and Calculate the DC and AC components at each projection angle, and sequentially obtain the demodulation results at N discrete frequency points to form a DC component group. With the communication component group DC component The imaging results, corresponding to traditional grating-free modulation, include structural artifacts and edge blur noise, and AC components. After grating coding modulation, noise is suppressed while high-frequency information is preserved; In step S2, the spatial frequency distribution of the grating-encoded X-rays is controlled, and the demodulation results at N discrete frequency points are obtained sequentially to obtain the DC component group. and communication component groups ; The modulation of the spatial frequency of grating coding has a characteristic correspondence with the penetration depth resolution capability. Specifically, low-frequency modulation mode can effectively enhance the imaging contrast of deep structures, while high-frequency modulation mode can significantly improve the detail resolution capability of surface and near-surface structures. The calculated DC component Compared to traditional X-ray tomography without grating-coded modulation, the images contain noise interference such as structural artifacts and blurred edges, while the AC component... Through grating coding modulation, key high-frequency information can be preserved while suppressing this type of noise interference.

[0026] Step S5: High-resolution 3D structure reconstruction by multi-spatial frequency fusion For projection data at different spatial frequencies, the Feldkamp, ​​Davis, and Kress algorithm is used to reconstruct the internal three-dimensional structure. Combined with a resolution evaluation algorithm, the MTF, FWHM, and PSNR indices are used to quantitatively evaluate the reconstructed image and select the optimal reconstruction layer at each spatial frequency. High MTF, low FWHM, and high PSNR generally indicate high image contrast and good detail preservation. To unify the quantitative indicators, normalization is first performed. For MTF and PSNR, forward normalization is used, while FWHM is reverse normalized to ensure that a larger value represents better quality. Weighting coefficients are set for comprehensive evaluation, specifically: MTF weight is 0.5, FWHM weight is 0.3, and PSNR weight is 0.2. The optimal reconstruction slices of different frequency bands are stacked and fused in a hierarchical manner to build a three-dimensional internal structure layer by layer, thereby achieving high-resolution three-dimensional reconstruction. Low-frequency modulation enhances the contrast of deep structures, while high-frequency modulation improves the resolution of surface and near-surface details. After a comprehensive evaluation based on image quality indicators, the system fuses the optimal reconstructed slices of different frequency bands at different levels to achieve full-depth high-resolution detail preservation, and finally obtains a three-dimensional X-ray tomography image with clear structure and rich detail. This method ensures that each reconstruction layer uses the clearest image data at the corresponding spatial frequency, thereby achieving full-depth preservation of high-resolution details during volume reconstruction and ultimately obtaining a three-dimensional high-resolution X-ray tomographic image with clear structure and rich details.

[0027] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A high-resolution X-ray tomography system, characterized in that, include: The grating-encoded emission unit consists of an X-ray source (2) and a piezoelectric ceramic mechanical grating (3). The piezoelectric ceramic mechanical grating (3) is located at the front end of the X-ray source (2) and together they form a grating-encoded X-ray emission end, which is used to emit X-rays modulated by spatial frequency. Planar detector (1): set opposite to the grating-encoded transmitter, used to collect X-ray projection data passing through the circuit board under test (4); Precision displacement control system: including lead screw and guide rail, servo motor, encoder and controller, adopting a fully closed-loop control architecture, used to adjust the distance between X-ray source (2) and piezoelectric ceramic mechanical grating (3), to achieve precise control of the spatial frequency of grating-encoded X-rays, wherein the distance... With spatial frequency satisfy: , The initial distance, The reference spatial frequency; Synchronous control unit: used to coordinate the phase shift of the piezoelectric ceramic driver to the mechanical grating, the angle control of the servo motor to the rotating platform, and the data acquisition of the planar detector (1) to realize the synchronous execution of tilted 360° rotation scanning and three-step phase shift; Image data processing unit: used to perform three-step phase-shift demodulation, multi-spatial-frequency three-dimensional reconstruction and image fusion on the projection data, and output high-resolution three-dimensional tomographic images.

2. The high-resolution X-ray tomography system according to claim 1, characterized in that, The synchronization control unit uses a closed-loop feedback mechanism to ensure synchronization at each scanning angle. The lower control mechanical grating completes three-step phase shifting to acquire projection data of different phases. The projection data expression is: ， ， ， in, The DC component, For the purpose of exchanging quantities, This is the initial phase.

3. The high-resolution X-ray tomography system according to claim 1, characterized in that, The image data processing unit includes: The demodulation unit uses a three-step phase-shift method to calculate the DC and AC components. The reconstruction and fusion unit uses the FDK algorithm to reconstruct the three-dimensional structure from projection data of different spatial frequencies. It comprehensively evaluates the modulation transfer function (MTF), full width at half maximum (FWHM), and peak signal-to-noise ratio (PSNR) to select the optimal reconstruction layer for each spatial frequency and fuses them layer by layer.

4. A high-resolution X-ray tomography method, applicable to the high-resolution X-ray tomography system described in any one of claims 1-3, characterized in that, Includes the following steps: Step S1: Construction of the grating-coded X-ray tomography system; The circuit board under test (4) is placed between the grating-encoded X-ray emitting end and the planar detector (1) to complete the system hardware connection and synchronous control parameter configuration, so that the planar detector (1), X-ray source (2) and piezoelectric ceramic mechanical grating (3) can be synchronously controlled. Step S2: Control the distance between the grating and the X-ray source (2) ; The distance between the X-ray source (2) and the piezoelectric ceramic mechanical grating (3) is adjusted sequentially by a precision displacement control system. It iterates through N preset discrete spatial frequency points, performing subsequent data acquisition and processing at each frequency point to complete a full-band scan from low to high frequencies; where the spacing... With spatial frequency The correspondence is as follows: ; Step S3: Control the grating phase shift and data acquisition ; The system synchronously controls the piezoelectric ceramic actuator to adjust the phase of the mechanical grating, performs a three-step phase shift according to a predetermined sequence, and simultaneously controls the rotating platform via a servo motor to drive the circuit board under test (4) to perform a tilted 360° rotation scan to acquire multi-angle projection data under different phases. ; Step S4: Three-step phase-shifting image demodulation ; The three-step phase-shift method is used to demodulate the three-step phase-shift projection data acquired at various angles, and the result is obtained through the formula. and The DC and AC components at each projection angle are calculated, and the demodulation results of N discrete frequency points are obtained in sequence to form a DC component group and an AC component group. The DC component corresponds to the imaging result of traditional non-grating-coded modulation, which includes structural artifacts and edge blur noise. The AC component suppresses noise and retains high-frequency information after grating-coded modulation. Step S5: High-resolution 3D structure reconstruction by multi-spatial frequency fusion; For projection data at different spatial frequencies, the FDK algorithm is used to reconstruct the internal three-dimensional structure. Combined with the resolution evaluation algorithm, the MTF, FWHM and PSNR indices are used to quantitatively evaluate the reconstructed image and select the optimal reconstruction layer at each spatial frequency. The optimal reconstructed slices of different frequency bands are stacked and fused in a hierarchical manner to build a three-dimensional internal structure layer by layer, thereby achieving high-resolution three-dimensional reconstruction. Low-frequency modulation enhances the contrast of deep structures, while high-frequency modulation improves the resolution of surface and near-surface details.

5. The high-resolution X-ray tomography method according to claim 4, characterized in that, In step S2, the precision displacement control system provides real-time feedback of the spacing via an encoder. This enables micron-level adjustment of the distance between the X-ray source (2) and the piezoelectric ceramic mechanical grating (3), ensuring continuous control of different spatial frequency bands.

6. The high-resolution X-ray tomography method according to claim 4, characterized in that, In step S5, the system comprehensively evaluates the image quality indicators and then fuses the optimal reconstructed slices of different frequency bands at different levels to achieve full-depth high-resolution detail preservation, ultimately obtaining a three-dimensional X-ray tomography image with clear structure and rich details.

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