Image bright field correction method and device for laser plasma accelerator, electronic equipment and storage medium

Abstract

The invention provides an image bright field correction method and device for a laser plasma accelerator, electronic equipment and a storage medium, and relates to the technical field of X-ray imaging. The method comprises the following steps: acquiring dark fields and initial X-ray beam spot images of an X-ray bright field calibration detector and an X-ray imaging detector to obtain coordinates of an initial X-ray beam spot center; under the condition that the imaging sample is moved in, a real-time unprocessed X-ray beam spot image obtained by the X-ray bright field calibration detector and a real-time unprocessed projection image obtained by the X-ray imaging detector are obtained, so that a real-time beam spot image and a real-time imaging image are obtained, and coordinates of a real-time X-ray beam spot center are obtained; according to the coordinate difference between the real-time X-ray beam spot center and the initial X-ray beam spot center, the X-ray beam spot center is obtained, and a final real-time projection image is obtained. According to the invention, the accuracy of bright field correction is improved by measuring the X-ray beam spot in real time and combining geometric space mapping and coordinate transformation.

Description

Technical Field

[0001] This application relates to the field of X-ray imaging technology, and more specifically, to a method, apparatus, electronic device, and storage medium for image brightness field correction in laser plasma accelerators. Background Technology

[0002] Laser-plasma accelerators, as a revolutionary next-generation accelerator technology, efficiently accelerate electrons by driving a wake field with an ultra-high accelerating gradient (>100 MeV / mm) in a rarefied plasma medium using ultrashort, ultra-intense lasers. Due to their micrometer-scale accelerating structure, they can generate X-rays with micrometer-scale source size and femtosecond-scale pulse length. Laser-accelerated ultrafast X-ray sources include broadband high-throughput Betatron synchrotron X-ray sources, quasi-mono-spectral all-optical inverse Compton scattering X-ray sources, and high-energy micro-focus all-optical bremsstrahlung sources. These sources possess significant advantages such as desktop scale, femtosecond-scale pulse length, micrometer-scale source size, ultra-high peak brightness, wide energy spectrum coverage, and adjustable energy and spectral width. They have enormous application potential in quantum science, physics, biology, medicine, and other disciplines, as well as in industrial fields such as weaponry, aerospace, and high-end manufacturing, and are expected to drive a series of technological revolutions and form a new high-tech industrial market.

[0003] However, for X-ray sources driven by laser-plasma accelerators, due to factors such as fluctuations in laser-plasma interaction parameters, mechanical vibrations, and changes in temperature and humidity, the morphology and transmission direction of the X-ray beam exhibit random fluctuations between beams and slow, long-term variations. In related imaging applications, especially in CT imaging, traditional methods of pre-acquiring the bright field struggle to achieve accurate bright field correction, resulting in the inability to obtain accurate sample attenuation coefficients from the projected image. This leads to significant errors in CT reconstruction results, severely limiting the further application of laser-plasma accelerator-driven X-ray sources in the imaging field.

[0004] Therefore, there is an urgent need for a method that can measure the X-ray beam spot in real time and achieve accurate brightness field correction. Summary of the Invention

[0005] To address at least one of the aforementioned problems, this application proposes a method, apparatus, electronic device, and storage medium for image brightness field correction in laser plasma accelerators.

[0006] According to a first aspect of this application, at least one embodiment of this application provides a method for image brightness field correction in a laser plasma accelerator. The method includes: acquiring dark field and initial X-ray beam spot images from an X-ray brightness field calibration detector and an X-ray imaging detector to obtain the coordinates of the initial X-ray beam spot center; when an imaging sample is moved in, acquiring a real-time unprocessed X-ray beam spot image acquired by the X-ray brightness field calibration detector and a real-time unprocessed projection image acquired by the X-ray imaging detector; obtaining a real-time beam spot image and a real-time imaging image based on the dark field of the X-ray brightness field calibration detector and the X-ray imaging detector, the real-time unprocessed X-ray beam spot image, and the real-time unprocessed projection image; obtaining the coordinates of the real-time X-ray beam spot center based on the real-time beam spot image; obtaining the X-ray beam spot center after coordinate translation transformation based on the coordinate difference between the real-time X-ray beam spot center and the initial X-ray beam spot center; and performing image brightness field correction based on the real-time beam spot image, the real-time imaging image, and the X-ray beam spot center to obtain a final real-time projection image.

[0007] For example, in some embodiments of this application, obtaining the dark field and initial X-ray beam spot images of the X-ray bright field calibration detector and the X-ray imaging detector to obtain the coordinates of the initial X-ray beam spot center includes: mapping the dark field and initial X-ray beam spot images of the X-ray bright field calibration detector to the field of view plane of the X-ray imaging detector to obtain a first dark field and a first X-ray beam spot image; obtaining a first initial beam spot image based on the first dark field and the first X-ray beam spot image of the X-ray bright field calibration detector; obtaining a second initial beam spot image based on the dark field and the initial X-ray beam spot image of the X-ray imaging detector; and fitting the first initial beam spot image or the second initial beam spot image to obtain the abscissa and ordinate of the initial X-ray beam spot center.

[0008] For example, in some embodiments of this application, the step of acquiring a real-time unprocessed X-ray beam spot image acquired by the X-ray bright field calibration detector and a real-time unprocessed projection image acquired by the X-ray imaging detector when the imaging sample is moved in, obtaining a real-time beam spot image and a real-time imaging image based on the dark field of the X-ray bright field calibration detector and the X-ray imaging detector, the real-time unprocessed X-ray beam spot image and the real-time unprocessed projection image, and obtaining the coordinates of the real-time X-ray beam spot center based on the real-time beam spot image, includes: mapping the real-time unprocessed X-ray beam spot image of the X-ray bright field calibration detector to the field of view plane of the X-ray imaging detector to obtain a third X-ray beam spot image; obtaining the real-time beam spot image based on the third X-ray beam spot image and the first dark field; obtaining the real-time imaging image based on the real-time unprocessed projection image and the dark field of the X-ray imaging detector; and fitting the real-time beam spot image to obtain the horizontal and vertical coordinates of the real-time X-ray beam spot center.

[0009] For example, in some embodiments of this application, obtaining the X-ray beam spot center after coordinate translation transformation based on the coordinate difference between the real-time X-ray beam spot center and the initial X-ray beam spot center, and performing image brightness field correction based on the real-time beam spot image, the real-time imaging image, and the X-ray beam spot center to obtain the final real-time projection image includes: obtaining the coordinate difference between the real-time X-ray beam spot center and the initial X-ray beam spot center based on the x-coordinate and y-coordinate of the initial X-ray beam spot center and the x-coordinate and y-coordinate of the real-time X-ray beam spot center; performing coordinate translation transformation on the first initial beam spot image and the second initial beam spot image based on the coordinate difference between the real-time X-ray beam spot center and the initial X-ray beam spot center to obtain the final X-ray beam spot center; and performing image brightness field correction based on the real-time beam spot image, the real-time imaging image, and the final X-ray beam spot center according to the following formula to obtain the final real-time projection image:

[0010]

[0011] Where I is the final real-time projected image, and A i For the real-time imaging image, B i The real-time beam spot image is defined as A'0 and B'0, which are the final X-ray beam spot centers.

[0012] For example, in some embodiments of this application, an X-ray source is provided between the laser plasma accelerator and the X-ray bright field calibration detector to generate X-ray pulses under the drive of the laser plasma accelerator. The method further includes: adjusting the laser target angle of the laser plasma accelerator and the position of the X-ray source according to the coordinate difference between the real-time X-ray beam spot center and the initial X-ray beam spot center.

[0013] For example, in some embodiments of this application, an electric optical frame is provided in the laser plasma accelerator, and adjusting the laser target angle of the laser plasma accelerator and the position of the X-ray source according to the coordinate difference between the real-time X-ray beam spot center and the initial X-ray beam spot center includes:

[0014] Adjust the laser target angle of the motorized optical frame to adjust the laser target angle of the laser plasma accelerator;

[0015] The angle adjustment amount of the motorized optical frame is determined according to the following formula:

[0016]

[0017] The positional translation of the X-ray source is determined according to the following formula:

[0018]

[0019] Wherein, δx and δy are the coordinate differences between the real-time X-ray beam spot center and the initial X-ray beam spot center, l is the distance between the motorized optical frame and the X-ray source, and L is the distance between the X-ray source and the X-ray bright field calibration detector.

[0020] According to a second aspect of this application, at least one embodiment of this application provides an apparatus for image brightness field correction of a laser plasma accelerator, the apparatus comprising: an X-ray source driven by the laser plasma accelerator to generate X-ray pulses; an X-ray brightness field calibration detector disposed between the X-ray source and an imaging sample, for acquiring dark field and initial X-ray beam spot images when the imaging sample is not moved in, and for acquiring real-time unprocessed X-ray beam spot images when the imaging sample is moved in; an X-ray imaging detector disposed after the imaging sample, for acquiring dark field and initial X-ray beam spot images when the imaging sample is not moved in, and for acquiring real-time unprocessed projection images when the imaging sample is moved in; and a host computer for executing the method described in the first aspect. The method described in any one of the following is used to obtain the coordinates of the initial X-ray beam spot center based on the dark field of the X-ray brightness field calibration detector and the X-ray imaging detector and the initial X-ray beam spot image; further used to obtain a real-time beam spot image and a real-time imaging image based on the dark field of the X-ray brightness field calibration detector and the X-ray imaging detector, the real-time unprocessed X-ray beam spot image and the real-time unprocessed projection image; used to obtain the coordinates of the real-time X-ray beam spot center based on the real-time beam spot image; used to obtain the X-ray beam spot center after coordinate translation transformation based on the coordinate difference between the real-time X-ray beam spot center and the initial X-ray beam spot center; and used to perform image brightness field correction based on the real-time beam spot image, the real-time imaging image and the X-ray beam spot center to obtain the final real-time projection image.

[0021] For example, in some embodiments of this application, it further includes: an electric optical frame disposed in the laser plasma accelerator; wherein, the host computer is further configured to adjust the laser target angle of the electric optical frame according to the coordinate difference between the real-time X-ray beam spot center and the initial X-ray beam spot center, so as to adjust the laser target angle of the laser plasma accelerator, and to adjust the position of the X-ray source.

[0022] According to a third aspect of this application, at least one embodiment of this application provides an electronic device, comprising: one or more processors; a memory for storing one or more programs; and, when the one or more programs are executed by the one or more processors, causing the one or more processors to perform the method as described in any one aspect of the first application.

[0023] According to a fourth aspect of this application, at least one embodiment of this application provides a computer-readable storage medium having a computer program stored thereon that, when executed by a processor, implements the method as described in any one of the first aspects.

[0024] Through the above-described exemplary embodiments, this application provides a method and apparatus for image brightness field correction in laser plasma accelerators. By measuring the X-ray beam spot in real time and combining geometric spatial mapping and coordinate transformation, it achieves dynamic tracking and correction of beam spot jitter and slow changes. This solves the problem that traditional pre-acquired brightness fields cannot adapt to real-time changes in the beam spot, significantly improving the accuracy of brightness field correction. Especially in CT imaging, it can effectively reduce reconstruction errors, improve the measurement accuracy of sample attenuation coefficients, and expand the application prospects of laser plasma accelerator-driven X-ray sources in the imaging field.

[0025] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this application. Attached Figure Description

[0026] The above and other objects, features, and advantages of this application will become more apparent from the detailed description of exemplary embodiments with reference to the accompanying drawings. The drawings described below are merely some embodiments of this application and are not intended to limit the scope of this application.

[0027] Figure 1 A flowchart illustrating an exemplary embodiment of a method for image brightness field correction in a laser plasma accelerator is shown.

[0028] Figure 2 This diagram illustrates the image data processing flow of the implementation process of this application in imaging applications.

[0029] Figure 3 This diagram illustrates the X-ray transmission direction compensation of this application.

[0030] Figure 4 This diagram illustrates the implementation process of this application in imaging applications;

[0031] Figure 5 A schematic diagram of an apparatus for image brightness field correction for a laser plasma accelerator, illustrating an exemplary embodiment;

[0032] Figure 6 A schematic diagram of an X-ray bright field calibration detector is shown;

[0033] Figure 7 The diagram shows the effect of implementing the method of this application;

[0034] Figure 8 This diagram illustrates the structure of an electronic device provided in this application. Detailed Implementation

[0035] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided so that this application will be thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted.

[0036] The described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a full understanding of embodiments of this disclosure. However, those skilled in the art will recognize that the technical solutions of this disclosure can be practiced without one or more of these specific details, or other methods, components, materials, devices, etc. In these cases, well-known structures, methods, devices, implementations, materials, or operations will not be shown or described in detail.

[0037] The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0038] The terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0039] Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams of exemplary embodiments, and the modules or processes in the drawings are not necessarily essential for implementing this application, and therefore cannot be used to limit the scope of protection of this application.

[0040] To address the problem of inaccurate brightness field correction and poor imaging quality caused by the jitter and slow changes in beam spot shape and transmission direction of laser plasma accelerator-driven X-ray sources in imaging applications, this application provides a method for achieving precise brightness field correction by measuring the X-ray beam spot in real time, thereby improving imaging accuracy, especially the reconstruction quality of CT imaging.

[0041] This application proposes a method for image brightness field correction in laser plasma accelerators.

[0042] Figure 1A flowchart illustrating an exemplary embodiment of a method for image brightness field correction in a laser plasma accelerator is shown.

[0043] like Figure 1 As shown, the method for image brightness field correction for laser plasma accelerators includes steps S1-S4.

[0044] Step S1: Obtain the dark field and initial X-ray beam spot images of the X-ray bright field calibration detector and the X-ray imaging detector to obtain the coordinates of the initial X-ray beam spot center.

[0045] Specifically, it includes:

[0046] S1.1, acquire the dark field and initial X-ray beam spot images of the X-ray bright field calibration detector and the X-ray imaging detector.

[0047] Dark fields D (dark field of the X-ray imaging detector) and d (dark field of the X-ray bright field calibration detector) are acquired separately, and the same X-ray beam spot image is acquired simultaneously, namely the initial unprocessed beam spot image G0 (initial X-ray beam spot image of the X-ray imaging detector) and g0 (initial X-ray beam spot image of the X-ray bright field calibration detector).

[0048] S1.2, map the dark field and initial X-ray beam spot image of the X-ray bright field calibration detector onto the field of view plane of the X-ray imaging detector to obtain the first dark field and first X-ray beam spot image.

[0049] By transforming the field of view, the dark field obtained from the X-ray bright field calibration detector and the initial unprocessed X-ray beam spot image are mapped onto the field of view plane of the X-ray imaging detector, i.e., d→D. ' , g0→G'0.

[0050] S1.3, Based on the first dark field and the first X-ray beam spot image of the X-ray bright field calibrating detector, obtain the first initial beam spot image.

[0051] S1.4, Based on the dark field of the X-ray imaging detector and the initial unprocessed X-ray beam spot image G0, obtain the second initial beam spot image.

[0052] The first initial beam spot image G'0-D' (denoted as B0, X-ray bright field calibration detector) and the second initial beam spot image G0-D (denoted as A0, X-ray imaging detector) after dark field subtraction are obtained.

[0053] S1.5, Fit the first initial beam spot image or the second initial beam spot image to obtain the abscissa and ordinate of the initial X-ray beam spot center.

[0054] Through forms such as The function is fitted to A0 or B0 to obtain the x-coordinate x0 and y-coordinate y0 of the initial X-ray beam spot center.

[0055] Step S2: With the imaging sample moved in, acquire the real-time unprocessed X-ray beam spot image acquired by the X-ray bright field calibration detector and the real-time unprocessed projection image acquired by the X-ray imaging detector. Based on the dark field of the X-ray bright field calibration detector and the X-ray imaging detector, the real-time unprocessed X-ray beam spot image and the real-time unprocessed projection image, obtain the real-time beam spot image and the real-time imaging image, and obtain the coordinates of the real-time X-ray beam spot center based on the real-time beam spot image.

[0056] Specifically, it includes:

[0057] The imaging sample is moved into the X-ray cone beam region for single-frame projection imaging.

[0058] S2.1, acquire the real-time unprocessed X-ray beam spot image acquired by the X-ray bright field calibration detector and the real-time unprocessed projection image acquired by the X-ray imaging detector.

[0059] The X-ray imaging detector acquires a real-time unprocessed projection image I0, while the X-ray brightness field calibration detector simultaneously acquires a real-time unprocessed X-ray beam spot image i0.

[0060] S2.2, map the real-time unprocessed X-ray beam spot image of the X-ray bright field calibration detector onto the field of view plane of the X-ray imaging detector to obtain the third X-ray beam spot image.

[0061] By transforming the field of view, the real-time unprocessed X-ray beam spot image obtained by the X-ray bright field calibration detector is mapped onto the field of view plane of the X-ray imaging detector to obtain the third X-ray beam spot image, i.e., i0→i ' 0.

[0062] S2.3, obtain a real-time beam spot image based on the third X-ray beam spot image and the first dark field.

[0063] S2.4 Obtain a real-time imaging image based on the real-time unprocessed projection image and the dark field of the X-ray imaging detector.

[0064] Obtain the real-time imaging image I0-D (denoted as A) after subtracting the dark field. i X-ray imaging detector) and real-time beam spot image I'0-D' (denoted as B) after dark field subtraction. i (X-ray bright field calibration detector).

[0065] S2.5, fit the real-time beam spot image to obtain the horizontal and vertical coordinates of the real-time X-ray beam spot center.

[0066] Through forms such as The function for real-time beamspot image B i By fitting the data, the x'0 and y'0 coordinates of the real-time X-ray beam spot center are obtained.

[0067] Step S3: Based on the coordinate difference between the real-time X-ray beam spot center and the initial X-ray beam spot center, obtain the X-ray beam spot center after coordinate translation transformation, and perform image brightness field correction based on the real-time beam spot image, the real-time imaging image, and the X-ray beam spot center to obtain the final real-time projection image.

[0068] Specifically, it includes:

[0069] S3.1, Based on the x and y coordinates of the initial X-ray beam spot center and the real-time X-ray beam spot center, obtain the coordinate difference between the real-time X-ray beam spot center and the initial X-ray beam spot center.

[0070] Obtain the coordinate difference between the real-time X-ray beam spot center and the initial X-ray beam spot center: δx = x'0 - x0, δy = y'0 - y0.

[0071] S3.2, Based on the coordinate difference between the real-time X-ray beam spot center and the initial X-ray beam spot center, perform coordinate translation transformation on the first initial beam spot image and the second initial beam spot image to obtain the X-ray beam spot center.

[0072] Based on the coordinate difference between the real-time X-ray beam spot center and the initial X-ray beam spot center, coordinate translation transformation is performed on the first initial beam spot image and the second initial beam spot image to obtain the final X-ray beam spot center, namely A0(x-δx,y-δy) (denoted as A'0, X-ray imaging detector) and B0(x-δx,y-δy) (denoted as B'0, X-ray brightness field calibration detector).

[0073] S3.3, Based on the real-time beam spot image, the real-time imaging image, and the final X-ray beam spot center, perform image brightness field correction according to the following formula to obtain the final real-time projection image:

[0074]

[0075] Where I represents the final real-time projected image, such as Figure 2 As shown, B i For real-time beamspot images, A i For real-time imaging, A'0 and B'0 are the centers of the X-ray beam spot.

[0076] Step S4: Adjust the laser target angle of the laser plasma accelerator and the position of the X-ray source based on the coordinate difference between the real-time X-ray beam spot center and the initial X-ray beam spot center.

[0077] Specifically, it includes:

[0078] An X-ray source is disposed between the laser plasma accelerator and the X-ray bright field calibration detector, and an electric optical frame is disposed in the laser plasma accelerator.

[0079] S4.1, Adjust the laser target angle of the motorized optical frame to adjust the laser target angle of the laser plasma accelerator; determine the angle adjustment amount of the motorized optical frame according to the following formula:

[0080]

[0081] S4.2, determine the positional translation of the X-ray source according to the following formula:

[0082]

[0083] Among them, such as Figure 3 As shown, δx and δy are the coordinate differences between the real-time X-ray beam spot center and the initial X-ray beam spot center, l is the distance between the motorized optical frame and the X-ray source, and L is the distance between the X-ray source and the X-ray bright field calibration detector.

[0084] Repeat steps S2-S4 until the imaging application ends.

[0085] In imaging applications, it is necessary to acquire multiple projection images of the imaging sample from multiple angles (for example, in CT imaging, projection data at different angles needs to be obtained by rotating the sample to complete three-dimensional reconstruction).

[0086] Therefore, in order to track the dynamic changes of the beam spot in real time: such as Figure 4 As shown, each time a projected image is acquired (S2), the offset of the beam spot center is remeasured (S3), the brightness field correction parameters are updated (S3), and the transmission direction is compensated (S4). This ensures that each acquisition of a projected image is corrected based on the actual state of the current beam spot, thereby continuously ensuring the accuracy of the brightness field correction. Ultimately, this solves the imaging error problem caused by the dynamic changes of the beam spot and meets the accuracy requirements of imaging applications for multi-frame and multi-angle projection data.

[0087] This application also provides an apparatus for image brightness field correction in laser plasma accelerators.

[0088] like Figure 5 As shown, the apparatus for image brightness field correction in a laser plasma accelerator includes: an X-ray source, an X-ray brightness field calibration detector, an X-ray imaging detector, and a host computer (not shown in the figure). The imaging sample is positioned between the X-ray brightness field calibration detector and the X-ray imaging detector. The imaging sample is not specifically limited in its type.

[0089] The X-ray source is driven by a laser plasma accelerator, which generates a cone-beam X-ray pulse with a spatial intensity distribution.

[0090] There are no special restrictions on the type of X-ray source, including Betatron ray sources driven by laser-plasma accelerators, inverse Compton scattering sources driven by laser-plasma accelerators, and bremsstrahlung sources driven by laser-plasma accelerators.

[0091] The X-ray bright-field calibration detector is positioned between the X-ray source and the imaging sample to record the X-ray beam spot in real time. When the imaging sample is not moved in, it is used to acquire dark-field and initial X-ray beam spot images; when the imaging sample is moved in, it is used to acquire real-time unprocessed X-ray beam spot images. The detection plane of the X-ray bright-field calibration detector should be as parallel as possible to the plane of the X-ray imaging detector and perpendicular to the X-ray transmission direction.

[0092] X-ray bright field calibration detectors include two types (such as...). Figure 6 (As shown): Scintillation screen X-ray detectors based on scintillation screens, optical imaging systems, and optical detectors (e.g., CCD, CMOS cameras); information recording X-ray detectors such as film or imaging plates (IP). To avoid the influence of the X-ray bright-field calibration detector on the X-ray spectrum, X-ray flux, and imaging resolution, the thickness of the photosensitive material (scintillation screen, film, or imaging plate) used in the X-ray bright-field calibration detector should be as thin as possible, provided that the signal-to-noise ratio of the signal acquired by the X-ray bright-field calibration detector is sufficient. Furthermore, to ensure the consistency of the X-ray signal response between the X-ray bright-field calibration detector and the X-ray imaging detector, it is recommended that the X-ray photosensitive material used in both detectors be the same. The X-ray cone region measured by the X-ray bright-field calibration detector should include the portion of the X-ray cone occupied by the imaging region.

[0093] The X-ray imaging detector is positioned behind the imaging sample to acquire dark field and initial X-ray beam spot images when the imaging sample is not moved in, and to acquire real-time unprocessed projection images when the imaging sample is moved in.

[0094] Because the installation angle of the detection plane of the X-ray bright-field calibration detector cannot guarantee absolute parallelism with the X-ray imaging detector, and because the optical imaging system of a scintillator-type X-ray detector suffers from field-of-view distortion, the X-ray bright-field calibration detector and the X-ray imaging detector should be geometrically calibrated in their field-of-view planes before imaging applications. This can be achieved using a commonly used method in optical systems—the Zhang Zhengyou calibration method—to establish the geometrical spatial mapping between the two. This application uses this as an example only, but is not limited to it.

[0095] The host computer is used to obtain the coordinates of the initial X-ray beam spot center based on the dark field and initial X-ray beam spot image of the X-ray brightness field calibration detector and X-ray imaging detector. It is also used to obtain the real-time beam spot image and real-time imaging image based on the dark field, real-time unprocessed X-ray beam spot image and real-time unprocessed projection image of the X-ray brightness field calibration detector and X-ray imaging detector. It is also used to obtain the coordinates of the real-time X-ray beam spot center based on the real-time beam spot image. Furthermore, it is used to obtain the X-ray beam spot center after coordinate translation transformation based on the coordinate difference between the real-time X-ray beam spot center and the initial X-ray beam spot center. Finally, it is used to perform image brightness field correction based on the real-time beam spot image, real-time imaging image and X-ray beam spot center to obtain the final real-time projection image.

[0096] The host computer is used to execute the image brightness field correction method for laser plasma accelerators as described above, so it will not be repeated here.

[0097] Devices for image brightness field correction in laser plasma accelerators also include motorized optical frames, such as... Figure 3 As shown, the motorized optical frame is installed in the laser plasma accelerator to adjust the laser target angle in real time, thereby indirectly controlling the direction of the X-ray beam.

[0098] The host computer is also used to adjust the laser target angle of the motorized optical frame based on the coordinate difference between the real-time X-ray beam spot center and the initial X-ray beam spot center, so as to adjust the laser target angle of the laser plasma accelerator.

[0099] The host computer is also used to adjust the position of the X-ray source based on the coordinate difference between the real-time X-ray beam spot center and the initial X-ray beam spot center.

[0100] This application provides a method and apparatus for image brightness field correction in laser plasma accelerators. By measuring the X-ray beam spot in real time and combining geometric space mapping and coordinate transformation, it achieves dynamic tracking and correction of beam spot jitter and slow changes. This solves the problem that traditional pre-acquired brightness fields cannot adapt to real-time changes in the beam spot, significantly improving the accuracy of brightness field correction. Especially in CT imaging, it can effectively reduce reconstruction errors, improve the measurement accuracy of sample attenuation coefficient, and expand the application prospects of laser plasma accelerator-driven X-ray sources in the imaging field.

[0101] The present application scheme is further illustrated below with reference to specific embodiments.

[0102] In this embodiment, the method of this application is applied to an imaging experiment (projection imaging of a dual-wire image quality meter) based on a laser-plasma accelerator-driven inverse Compton scattering X-ray source. The driving main laser beam used in the experiment has a target pulse energy of 0.3 joules, a pulse width of 22 femtoseconds, and a focal diameter of 12 micrometers (full width at half maximum); the colliding laser beam has a pulse energy of 0.13 joules, a pulse width of 200 femtoseconds, and a focal diameter of 7 micrometers (full width at half maximum). The plasma source is generated by a Delaware-type supersonic nozzle with an exit diameter of 2 mm. The X-ray bright field calibration detector uses an imaging plate, and the X-ray detector uses a flat panel detector.

[0103] Experimental results are as follows Figure 7 As shown, the brightness uniformity of the image after correction by the method of this application is significantly improved, and the detail clarity is significantly improved, proving the effectiveness of the method.

[0104] Figure 8 This diagram illustrates the structure of an electronic device provided in this application.

[0105] See Figure 8 , Figure 8 An electronic device is provided, including a processor and a memory. The memory stores computer instructions, which, when executed by the processor, cause the processor to perform the computer instructions to achieve the following: Figures 1-5 The method and its detailed scheme are shown.

[0106] It should be understood that the above-described device embodiments are merely illustrative, and the device disclosed in this application can also be implemented in other ways. For example, the division of units / modules in the above embodiments is only a logical functional division, and there may be other division methods in actual implementation. For example, multiple units, modules, or components may be combined, or integrated into another system, or some features may be ignored or not executed.

[0107] Furthermore, unless otherwise specified, the functional units / modules in the various embodiments of this application can be integrated into one unit / module, or each unit / module can exist physically separately, or two or more units / modules can be integrated together. The integrated units / modules described above can be implemented in hardware or as software program modules.

[0108] When integrated units / modules are implemented in hardware, the hardware can be digital circuits, analog circuits, etc. The physical implementation of the hardware structure includes, but is not limited to, transistors, memristors, etc. Unless otherwise specified, the processor or chip can be any suitable hardware processor, such as a CPU, GPU, FPGA, DSP, and ASIC, etc. Unless otherwise specified, on-chip cache, off-chip memory, and storage can be any suitable magnetic or magneto-optical storage medium, such as Resistive Random Access Memory (RRAM), Dynamic Random Access Memory (DRAM), Static Random Access Memory (SRAM), Enhanced Dynamic Random Access Memory (EDRAM), High-Bandwidth Memory (HBM), Hybrid Memory Cube (HMC), etc.

[0109] If the integrated unit / module is implemented as a software program module and sold or used as an independent product, it can be stored in a computer-readable storage device (CMD). Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a memory and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments disclosed herein. The aforementioned memory includes various media capable of storing program code, such as a USB flash drive, read-only memory (ROM), random access memory (RAM), portable hard drive, magnetic disk, or optical disk.

[0110] This application also provides a non-transitory computer storage medium storing a computer program, which, when executed by multiple processors, causes the processors to perform actions such as... Figures 1-5 The method and its detailed scheme are shown.

[0111] It should be clearly understood that this application describes how specific examples are formed and used, but this application is not limited to any details of these examples. Rather, based on the teachings of the disclosure of this application, these principles can be applied to many other embodiments.

[0112] Furthermore, it should be noted that the above figures are merely illustrative representations of the processes included in the method according to exemplary embodiments of this application, and are not intended to be limiting. It is readily understood that the processes shown in the above figures do not indicate or limit the temporal order of these processes. Additionally, it is readily understood that these processes may be executed synchronously or asynchronously, for example, in multiple modules.

[0113] Exemplary embodiments of this application have been specifically shown and described above. It should be understood that this application is not limited to the detailed structures, arrangements, or implementation methods described herein; rather, this application is intended to cover various modifications and equivalent arrangements that fall within the objectives and scope of the appended claims.

Claims

1. A method for image brightness field correction in laser plasma accelerators, characterized in that, The method includes: Acquire the dark field and initial X-ray beam spot images of the X-ray bright field calibration detector and the X-ray imaging detector to obtain the coordinates of the initial X-ray beam spot center; When the imaging sample is moved in, the real-time unprocessed X-ray beam spot image acquired by the X-ray bright field calibration detector and the real-time unprocessed projection image acquired by the X-ray imaging detector are obtained. Based on the dark field of the X-ray bright field calibration detector and the X-ray imaging detector, the real-time unprocessed X-ray beam spot image and the real-time unprocessed projection image, the real-time beam spot image and the real-time imaging image are obtained, and the coordinates of the real-time X-ray beam spot center are obtained based on the real-time beam spot image. Based on the coordinate difference between the real-time X-ray beam spot center and the initial X-ray beam spot center, the X-ray beam spot center after coordinate translation transformation is obtained. Then, based on the real-time beam spot image, the real-time imaging image, and the X-ray beam spot center, image brightness field correction is performed to obtain the final real-time projection image.

2. The method as described in claim 1, characterized in that, The process of acquiring the dark field and initial X-ray beam spot images of the X-ray bright field calibration detector and the X-ray imaging detector to obtain the coordinates of the initial X-ray beam spot center includes: The dark field and initial X-ray beam spot image of the X-ray bright field calibration detector are mapped onto the field of view plane of the X-ray imaging detector to obtain the first dark field and first X-ray beam spot image; A first initial beam spot image is obtained based on the first dark field and the first X-ray beam spot image of the X-ray bright field calibration detector. Based on the dark field of the X-ray imaging detector and the initial X-ray beam spot image, a second initial beam spot image is obtained; The first initial beam spot image or the second initial beam spot image is fitted to obtain the x-coordinate and y-coordinate of the center of the initial X-ray beam spot.

3. The method as described in claim 2, characterized in that, When the imaging sample is moved in, the process involves acquiring a real-time unprocessed X-ray beam spot image acquired by the X-ray bright field calibration detector and a real-time unprocessed projection image acquired by the X-ray imaging detector. Based on the dark field of the X-ray bright field calibration detector and the X-ray imaging detector, the real-time unprocessed X-ray beam spot image, and the real-time unprocessed projection image, a real-time beam spot image and a real-time imaging image are obtained. The coordinates of the real-time X-ray beam spot center are then obtained based on the real-time beam spot image. The real-time unprocessed X-ray beam spot image of the X-ray bright field calibration detector is mapped onto the field of view plane of the X-ray imaging detector to obtain a third X-ray beam spot image; The real-time beam spot image is obtained based on the third X-ray beam spot image and the first dark field; The real-time imaging image is obtained based on the real-time unprocessed projection image and the dark field of the X-ray imaging detector; The real-time beam spot image is fitted to obtain the horizontal and vertical coordinates of the real-time X-ray beam spot center.

4. The method as described in claim 3, characterized in that, The process of obtaining the X-ray beam spot center after coordinate translation transformation based on the coordinate difference between the real-time X-ray beam spot center and the initial X-ray beam spot center, and performing image brightness field correction based on the real-time beam spot image, the real-time imaging image, and the X-ray beam spot center to obtain the final real-time projection image includes: The coordinate difference between the real-time X-ray beam spot center and the initial X-ray beam spot center is obtained based on the x and y coordinates of the initial X-ray beam spot center and the real-time X-ray beam spot center. Based on the coordinate difference between the real-time X-ray beam spot center and the initial X-ray beam spot center, the first initial beam spot image and the second initial beam spot image are subjected to coordinate translation transformation to obtain the final X-ray beam spot center. Based on the real-time beam spot image, the real-time imaging image, and the final X-ray beam spot center, image brightness field correction is performed according to the following formula to obtain the final real-time projection image: Where I is the final real-time projected image, and A i For the real-time imaging image, B i The real-time beam spot image is defined as A'0 and B'0, which are the final X-ray beam spot centers.

5. The method as described in claim 1, characterized in that, An X-ray source is disposed between the laser plasma accelerator and the X-ray bright-field calibration detector for generating X-ray pulses under the drive of the laser plasma accelerator; the method further includes: Based on the coordinate difference between the real-time X-ray beam spot center and the initial X-ray beam spot center, the laser target angle of the laser plasma accelerator and the position of the X-ray source are adjusted.

6. The method as described in claim 5, characterized in that, The laser plasma accelerator is equipped with an electric optical frame. Adjusting the laser target angle of the laser plasma accelerator and the position of the X-ray source based on the coordinate difference between the real-time X-ray beam spot center and the initial X-ray beam spot center includes: Adjust the laser target angle of the motorized optical frame to adjust the laser target angle of the laser plasma accelerator; The angle adjustment amount of the motorized optical frame is determined according to the following formula: The positional translation of the X-ray source is determined according to the following formula: Where, δ x δ y Let l be the coordinate difference between the real-time X-ray beam spot center and the initial X-ray beam spot center, l be the distance between the motorized optical frame and the X-ray source, and L be the distance between the X-ray source and the X-ray bright field calibration detector.

7. An apparatus for image brightness field correction in a laser plasma accelerator, characterized in that, The device includes: The X-ray source, driven by the laser plasma accelerator, generates X-ray pulses; An X-ray bright field calibration detector is positioned between the X-ray source and the imaging sample. When the imaging sample is not moved in, it is used to acquire dark field and initial X-ray beam spot images, and when the imaging sample is moved in, it is used to acquire real-time unprocessed X-ray beam spot images. An X-ray imaging detector is positioned behind the imaging sample to acquire dark field and initial X-ray beam spot images when the imaging sample is not moved in, and to acquire real-time unprocessed projection images when the imaging sample is moved in. The host computer is configured to execute the method as described in any one of claims 1-6, and to obtain the coordinates of the initial X-ray beam spot center based on the dark field and the initial X-ray beam spot image of the X-ray brightness field calibration detector and the X-ray imaging detector. It is also configured to obtain a real-time beam spot image and a real-time imaging image based on the dark field of the X-ray brightness field calibration detector and the X-ray imaging detector, the real-time unprocessed X-ray beam spot image, and the real-time unprocessed projection image. Furthermore, it is configured to obtain the coordinates of the real-time X-ray beam spot center based on the real-time beam spot image, and to obtain the X-ray beam spot center after coordinate translation transformation based on the coordinate difference between the real-time X-ray beam spot center and the initial X-ray beam spot center. Finally, it is configured to perform image brightness field correction based on the real-time beam spot image, the real-time imaging image, and the X-ray beam spot center to obtain the final real-time projection image.

8. The apparatus as claimed in claim 7, characterized in that, Also includes: An electric optical frame is installed in the laser plasma accelerator; The host computer is also used to adjust the laser target angle of the motorized optical frame according to the coordinate difference between the real-time X-ray beam spot center and the initial X-ray beam spot center, so as to adjust the laser target angle of the laser plasma accelerator, and to adjust the position of the X-ray source.

9. An electronic device, characterized in that, include: One or more processors; Memory, used to store one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors perform the method as described in any one of claims 1-6.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the method as described in any one of claims 1-6.

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