A method and apparatus for flat panel detector image correction

Abstract

The application provides a flat panel detector image correction method and device, which comprises the following steps: firstly, collecting a bright field image at an initial angle and a bright field image at a plurality of preset swing angles, and processing the bright field image at the initial angle to obtain a gain correction template at the initial angle; then, processing the bright field images at all swing angles according to the gain correction template at the initial angle to obtain a light field conversion coefficient template at each swing angle; obtaining an angle light field conversion function according to the light field conversion coefficient template at the initial angle and the light field conversion coefficient templates at all swing angles; obtaining a gain correction template at a to-be-tested angle based on the angle light field conversion function; and performing gain correction on the bright field image at the to-be-tested angle according to the gain correction template at the to-be-tested angle, and obtaining a corrected image at the to-be-tested angle. The application can quickly perform gain correction on multiple angles, improves work efficiency and saves cost under the premise of ensuring image quality.

Description

Technical Field

[0001] This invention relates to the field of image processing technology, and in particular to a method and apparatus for image correction of a flat panel detector. Background Technology

[0002] Flat panel detectors are known for their fast imaging speed and high resolution, and are widely used in medical testing, non-destructive testing, security inspection, and counter-terrorism. However, during the imaging process of flat panel detectors, factors such as the uniformity of the X-ray tube irradiation field, dead pixels, and dark field noise can reduce image quality, necessitating correction.

[0003] Currently, most methods employ the separate acquisition of multiple images for gain and defect correction, resulting in good correction effects and high image quality. However, for applications like Tomo, this approach has drawbacks such as requiring a large number of images, demanding high X-ray irradiation levels, and involving complex defect template calculations, making it time-consuming and labor-intensive. Another method uses a single image for gain correction, which is convenient and fast, but the resulting image exhibits significantly higher noise levels compared to images corrected from multiple images. This leads to a decline in key evaluation indicators for flat panel detectors, such as noise equivalent dose (NED), noise power spectrum (NPS), and quantum detection efficiency (DQE). Therefore, the image correction quality of current flat panel detectors is poor. Summary of the Invention

[0004] In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide a method and apparatus for image correction of flat panel detectors, so as to solve the problem of poor image correction quality of flat panel detectors in the prior art.

[0005] To achieve the above and other related objectives, the present invention provides a method for image correction of a flat panel detector, characterized in that the method includes at least:

[0006] A bright field image of the X-ray source irradiating at an initial angle is acquired, and the bright field image at the initial angle is processed to obtain a gain correction template for the initial angle.

[0007] Multiple swing angles are preset, and a bright field image of the X-ray source irradiating at each swing angle is acquired; wherein the swing angle is different from the initial angle;

[0008] The light field conversion coefficient template for each swing angle is obtained by processing the bright field images of all swing angles based on the gain correction template of the initial angle.

[0009] The angle light field conversion function is obtained based on the light field conversion coefficient template of the initial angle and the light field conversion coefficient templates of all swing angles.

[0010] The gain correction template for the angle to be measured is obtained based on the angle light field conversion function.

[0011] Gain correction is performed on the bright field image of the angle to be measured using the gain correction template of the angle to be measured, and a corrected image of the angle to be measured is obtained.

[0012] Preferably, processing the brightness field image of the initial angle to obtain the gain correction template for the initial angle includes:

[0013] The bright field image of the initial angle is processed to obtain the grayscale reference value of the initial angle;

[0014] The gain correction template for the initial angle is obtained based on the grayscale reference value of the initial angle and the bright field image of the initial angle.

[0015] Preferably, bright field images are acquired when the X-ray source irradiates at a certain exposure dose or multiple different exposure doses at an initial angle;

[0016] When a bright field image is acquired when the X-ray source irradiates a certain exposure dose at an initial angle, a gain correction template for the initial angle is obtained.

[0017] Bright field images of multiple initial angles are obtained by acquiring images of the X-ray source irradiated with multiple different exposure doses.

[0018] Preferably, processing the bright field images of all the swing angles according to the gain correction template of the initial angle to obtain the light field conversion coefficient template for each swing angle includes:

[0019] The bright field image of each swing angle is processed according to the gain correction template of the initial angle to obtain the polarized image of each swing angle;

[0020] The polarized light images at each swing angle are processed to obtain the light field conversion coefficient templates for each swing angle.

[0021] Preferably, processing the bright field image of each swing angle according to the gain correction template of the initial angle to obtain the polarized image of each swing angle includes:

[0022] A gain correction reference template for the swing angle is determined based on the gain correction template of the initial angle and the bright field image of the swing angle.

[0023] The polarized light image at each swing angle is obtained based on the gain correction reference template at each swing angle and the bright field image at each swing angle.

[0024] Preferably, when there is one gain correction template for the initial angle, the gain correction reference template for each swing angle is determined as follows:

[0025] (1) Obtain the grayscale reference value of the swing angle (i.e., the grayscale reference value of the bright field image of the swing angle);

[0026] (2) Obtain the gain correction reference template for the swing angle based on the grayscale reference value of the swing angle and the gain correction template of the initial angle.

[0027] Preferably, when there are multiple gain correction templates for the initial angle, the gain correction reference template for each swing angle is determined as follows:

[0028] (1) Obtain the grayscale reference value of the swing angle (i.e., the grayscale reference value of the bright field image of the swing angle);

[0029] (2) Determine the gain correction reference template for the swing angle based on the grayscale reference value of the swing angle and the grayscale reference values ​​of multiple initial angles;

[0030] (3) Obtain the gain correction template for the swing angle based on the grayscale reference value of the swing angle and the gain correction reference template for the swing angle.

[0031] Preferably, the process of processing the polarized image at each swing angle to obtain the light field conversion coefficient template for the swing angle includes:

[0032] Normalize the polarized image at the swing angle to obtain the normalized gray value of the polarized image.

[0033] The light field conversion coefficient template for the swing angle is obtained based on the normalized gray value of the polarized image and the corresponding polarized image.

[0034] Preferably, the gain correction template for obtaining the angle to be measured based on the angle light field conversion function includes a light field conversion coefficient template for obtaining the angle to be measured based on the angle light field conversion function;

[0035] The gain correction template for the angle to be measured is obtained based on the optical field conversion coefficient template for the angle to be measured and the gain correction reference template for the angle to be measured.

[0036] To achieve the above and other related objectives, the present invention also provides an apparatus for image correction of a flat panel detector, comprising a memory, a processor, and a program stored in the memory and executable on the processor. When the processor executes the program, it implements the steps of the above-described method for correcting the bright field image of a flat panel detector.

[0037] As described above, the gain correction template generation method and image correction method for flat panel detectors of the present invention have the following beneficial effects:

[0038] This invention first acquires a bright field image at an initial angle and a bright field image at multiple preset swing angles, and processes the bright field image at the initial angle to obtain a gain correction template for the initial angle. Then, based on the gain correction template for the initial angle, it processes the bright field images at all the swing angles to obtain a light field conversion coefficient template for each swing angle. Next, it obtains an angle light field conversion function based on the light field conversion coefficient templates for the initial angle and all the swing angles. Then, it obtains a gain correction template for the angle to be measured based on the angle light field conversion function. Finally, it performs gain correction on the bright field image of the angle to be measured using the gain correction template for the angle to be measured, obtaining a corrected image of the angle to be measured. This invention enables rapid gain correction for multiple angles and also solves the technical shortcomings of existing technologies, such as requiring a large number of images or having high image noise, thus improving work efficiency and reducing operating costs. Attached Figure Description

[0039] Figure 1 The diagram shows the swinging motion of the X-ray source in the flat panel detector of the present invention.

[0040] Figure 2 The diagram shows a flowchart of the method for image correction of a flat panel detector according to the present invention. Detailed Implementation

[0041] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0042] Please see Figure 1-2 It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0043] Method Implementation Examples:

[0044] like Figure 1 The diagram shown is a schematic representation of the oscillation of the X-ray source in the flat panel detector of this invention. Figure 2 The diagram shows a flowchart of the image correction method for a flat panel detector. Figure 1-2 The method for image correction of a flat panel detector in this invention is described in detail. The method includes:

[0045] S1, acquire a bright field image of the X-ray source irradiating at an initial angle, and process the bright field image at the initial angle to obtain a gain correction template for the initial angle.

[0046] This invention acquires a bright field image of the X-ray source irradiated at an initial angle after the detector is powered on and preheated.

[0047] In this embodiment of the invention, a bright field image is acquired when the X-ray source irradiates at an initial angle with a certain exposure dose or multiple different exposure doses;

[0048] One bright field image can be acquired at one exposure dose, or multiple bright field images can be acquired repeatedly; the minimum number of bright field images acquired at multiple different exposure doses is the same as the number of exposure doses.

[0049] In this embodiment of the invention, processing the bright field image of the initial angle to obtain the gain correction template for the initial angle includes:

[0050] S11, Process the bright field image of the initial angle to obtain the grayscale reference value of the initial angle;

[0051] This invention processes a bright field image of a collected X-ray source irradiated at a certain exposure dose at an initial angle to obtain a grayscale reference value for the initial angle.

[0052] Bright field images of the acquired X-ray source irradiated at multiple different exposure doses at the initial angle are processed to obtain multiple grayscale reference values ​​for the initial angle; the number of grayscale reference values ​​for the initial angle is the same as the number of exposure doses.

[0053] Here, the grayscale reference value refers to the fact that the grayscale value of each pixel in the bright field image is the same. Specifically, the grayscale value of each pixel in the bright field image is averaged, and then the average grayscale value is assigned to each pixel. Then the same grayscale value of each pixel is the mean. In other implementation methods, the grayscale reference value is the median, the maximum value, etc.

[0054] Specifically, a bright field image is acquired when the X-ray source irradiates at a certain exposure dose at an initial angle, and the bright field image is processed to obtain a grayscale reference value.

[0055] Specifically, when the X-ray source irradiates at a certain exposure dose at the initial angle, a set of bright field images (multiple bright field images) are acquired. The multiple bright field images are processed to obtain the sub-grayscale reference values ​​of each bright field image. Then, the sub-grayscale reference values ​​of all bright field images are averaged to obtain the grayscale reference value of the set of bright field images at the initial angle, that is, the grayscale reference value of an initial angle.

[0056] Specifically, when acquiring multiple bright field images at different exposure doses at an initial angle, the multiple bright field images are processed to obtain a grayscale reference value at the initial angle corresponding to each exposure dose. One or more images can be acquired for each exposure dose, and the processing procedure for obtaining the grayscale reference value at the initial angle for each exposure dose is the same as the process described above for acquiring one or more bright field images at a certain exposure dose at an initial angle to obtain the grayscale reference value for the initial angle.

[0057] It should be noted that the grayscale reference value of a bright-field image at the initial angle can be the entire image domain or a local region.

[0058] S12, obtain the gain correction template for the initial angle based on the grayscale reference value of the initial angle and the bright field image of the initial angle.

[0059] First, obtain the original grayscale value of the bright field image at the initial angle, and then obtain the gain correction template for the initial angle based on the original grayscale value and the grayscale reference value.

[0060]

[0061] As can be seen from step S11, there are one or more grayscale reference values ​​for the initial angle of the present invention.

[0062] When there is one grayscale reference value for the initial angle, a gain correction template for the initial angle is obtained;

[0063] When there are multiple grayscale reference values ​​for the initial angle, multiple gain correction templates for the initial angle are obtained; wherein, the number of gain correction templates for the initial angle is the same as the number of grayscale reference values ​​for the initial angle.

[0064] Specifically, the original grayscale values ​​of the bright field images at different exposure doses are first obtained, and different gain correction templates for the initial angle are obtained based on each original grayscale value and grayscale reference value.

[0065] S2, multiple swing angles are preset, and a bright field image of the X-ray source irradiating at each swing angle is acquired; wherein the swing angle is different from the initial angle;

[0066] In this embodiment of the invention, if there are other flat panel detectors of the same type, the swing angle is set according to the swing pattern of these detectors. Alternatively, the setting can be customized according to the needs of the technician. For example, the swing angle can be set to ±5°, ±10°, ±20°, etc.

[0067] S3, process the bright field images of all the swing angles according to the gain correction template of the initial angle to obtain the light field conversion coefficient template for each swing angle;

[0068] This step aims to obtain the light field conversion coefficient templates for various swing angles, specifically including:

[0069] S31, The bright field image of each swing angle is processed according to the gain correction template of the initial angle to obtain the polarized image of each swing angle;

[0070] The bright field image at each swing angle is processed according to the gain correction template of the initial angle to obtain the polarized image at each swing angle, including:

[0071] S311, Determine the gain correction reference template for the swing angle based on the gain correction template of the initial angle and the bright field image of the swing angle;

[0072] Specifically, this step involves determining the gain correction reference template for each swing angle based on the gain correction template of the initial angle and the original grayscale values ​​of the bright field images of each swing angle.

[0073] Since the present invention has one or more gain correction templates for the initial angle, the method of determining the gain correction reference template for the swing angle is different when the number of gain correction templates for the initial angle is different.

[0074] When there is one gain correction template for the initial angle, the gain correction reference template for each swing angle is determined as follows:

[0075] (1) Obtain the grayscale reference value of the swing angle (i.e., the grayscale reference value of the bright field image of the swing angle);

[0076] In this step, the grayscale reference value of the swing angle is obtained in the same way as the grayscale reference value of the initial angle.

[0077] (2) Obtain the gain correction reference template for the swing angle based on the grayscale reference value of the swing angle and the gain correction template of the initial angle;

[0078] This step involves coupling the grayscale reference value of the swing angle with the gain correction template of the initial angle to obtain the gain correction reference template for the swing angle; the coupling process is as follows:

[0079] Initial angle gain correction template × grayscale reference value of swing angle = gain correction reference template of swing angle

[0080] When there are multiple gain correction templates for the initial angle, the gain correction reference template for each swing angle is determined as follows:

[0081] (1) Obtain the grayscale reference value of the swing angle (i.e., the grayscale reference value of the bright field image of the swing angle);

[0082] In this step, the grayscale reference value of the swing angle is obtained in the same way as the grayscale reference value of the initial angle.

[0083] (2) Determine the gain correction reference template for the swing angle based on the grayscale reference value of the swing angle and the grayscale reference values ​​of multiple initial angles;

[0084] In this step, the relationship between the grayscale reference value of the swing angle and the grayscale reference values ​​of multiple initial angles is first determined, and then the gain correction reference template for each swing angle is redefined; specifically as follows:

[0085] If the grayscale reference value of the swing angle is located between the grayscale reference values ​​of two initial angles, the gain correction reference template of the swing angle is obtained by interpolation.

[0086] If the gray value of the swing angle is less than the gray value of the minimum initial angle, then the gain correction template of the initial angle corresponding to the gray value of the minimum initial angle is used as the gain correction reference template for the swing angle.

[0087] If the gray value of the swing angle is greater than the gray value of the maximum initial angle, then the gain correction template of the initial angle corresponding to the gray value of the maximum initial angle is used as the gain correction reference template for the swing angle.

[0088] (3) Obtain the gain correction template for the swing angle based on the grayscale reference value of the swing angle and the gain correction reference template for the swing angle.

[0089] This step involves coupling the grayscale reference value of the swing angle with the gain correction reference template of the swing angle to obtain the gain correction template of the swing angle; the coupling process is as follows:

[0090] Gain correction reference template for swing angle × grayscale reference value of swing angle = gain correction template for swing angle

[0091] S312, obtain the polarized image at each swing angle based on the gain correction reference template at each swing angle and the bright field image at each swing angle.

[0092] This step first obtains the original grayscale values ​​of the bright field image at each swing angle (i.e., the original grayscale values ​​of the swing angle), and then couples the original grayscale values ​​of the swing angle with the gain correction reference template of its swing angle to obtain the polarized image of the swing angle. The coupling method for the polarized image at each swing angle is as follows:

[0093] Gain correction reference template for swing angle × Original grayscale value of swing angle = Polarized image of swing angle

[0094] S32, process the polarized light images at each swing angle to obtain the light field conversion coefficient templates for each swing angle.

[0095] In this step, the process of processing the polarized image at each swing angle to obtain the light field conversion coefficient template for the swing angle includes:

[0096] S321, Normalize the polarized image of the swing angle to obtain the normalized gray value of the polarized image.

[0097] In this step, the original grayscale value of the polarized image at the swing angle is first obtained, and then the normalized grayscale value of the polarized image is obtained based on the original grayscale value of the polarized image. The normalization process for obtaining the normalized grayscale value of the polarized image is the same as the process for obtaining the grayscale reference value of the initial angle. Therefore, the normalized grayscale value means that the grayscale value of each pixel in the polarized image is the same.

[0098] S322, obtain the light field conversion coefficient template of the swing angle based on the normalized gray value of the polarized image and the corresponding polarized image.

[0099] In this step, the original grayscale value of the polarized image at the swing angle is first obtained, and then the light field conversion coefficient template corresponding to the swing angle is obtained based on the original grayscale value of the polarized image and the normalized grayscale value of the polarized image; specifically as follows:

[0100]

[0101] S4. Obtain the angle light field conversion function based on the light field conversion coefficient template of the initial angle and the light field conversion coefficient template of all swing angles;

[0102] In this invention, the light field conversion coefficient of the initial angle does not need to be converted again; therefore, the template for the light field conversion coefficient of the initial angle is 1.

[0103] The angle light field conversion function is obtained by fitting the light field conversion coefficient templates for the initial angle and all swing angles. Specifically, the angle is used as the independent variable, and the corresponding light field conversion coefficient template is used as the dependent variable. A fitting process (such as a polynomial, exponential function, or trigonometric function) is then performed to obtain the angle light field conversion function. Therefore, the obtained angle light field conversion function represents the functional relationship between the angle and its corresponding light field conversion coefficient template.

[0104] S5, obtain the gain correction template for the angle to be measured based on the angle light field conversion function;

[0105] This step aims to redetermine the gain correction template for the angle to be measured. The present invention obtains the gain correction template for the angle to be measured based on the angle optical field conversion function, including...

[0106] S51, obtain the light field conversion coefficient template of the angle to be measured based on the angle light field conversion function;

[0107] In this step, the light field conversion coefficient template of the angle to be measured can be obtained by substituting the angle to be measured into the angle light field conversion function.

[0108] S52, the gain correction template of the angle to be measured is obtained based on the light field conversion coefficient template of the angle to be measured and the gain correction reference template of the angle to be measured;

[0109] This step requires first acquiring the bright field image of the angle to be measured and determining its original grayscale value. Then, the gain correction reference template for the angle to be measured is redefined using the method described in step S311. Finally, the gain correction template for the angle to be measured is determined based on the gain correction reference template and the light field conversion coefficient template of the angle to be measured. Specifically, as follows:

[0110] The optical field conversion coefficient template of the angle to be measured × the gain correction reference template of the angle to be measured = the gain correction template of the angle to be measured

[0111] S6, perform gain correction on the bright field image of the angle to be measured according to the gain correction template of the angle to be measured, and obtain the corrected image of the angle to be measured.

[0112] This step uses a newly determined gain correction template for the angle under test to perform gain correction on the bright field image of the angle under test, resulting in a corrected image of the angle under test. The corrected image of the angle under test is more accurate.

[0113] The gain correction process includes:

[0114] Corrected image of the angle to be measured = Original grayscale value of the bright field image of the angle to be measured × Gain correction template of the angle to be measured

[0115] This invention enables rapid multi-angle correction, improving work efficiency and saving costs while ensuring image quality.

[0116] Device Example:

[0117] To address the aforementioned technical deficiencies, the present invention also provides an apparatus for image correction of a flat panel detector. The apparatus includes a memory, a processor, and a program stored in the memory and executable on the processor. When the processor executes the program, it implements the steps of the aforementioned method for image correction of a flat panel detector.

[0118] The detailed process of the image correction method for the flat panel detector in this invention has been described in detail in the method embodiments and will not be repeated here.

[0119] In summary, this invention provides a method and apparatus for image correction of a flat panel detector, and a method for rapid gain correction from multiple angles. This addresses the technical shortcomings of existing technologies, such as the need for large image acquisition quantities or high image noise, thereby improving work efficiency and reducing operating costs. Therefore, this invention effectively overcomes the various drawbacks of existing technologies and has high industrial applicability.

[0120] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for image correction of a flat panel detector, characterized in that, The method includes at least: A bright field image of the X-ray source irradiating at an initial angle is acquired, and the bright field image at the initial angle is processed to obtain a gain correction template for the initial angle. Multiple swing angles are preset, and a bright field image of the X-ray source irradiating at each swing angle is acquired; wherein the swing angle is different from the initial angle; The light field conversion coefficient template for each swing angle is obtained by processing the bright field images of all swing angles based on the gain correction template of the initial angle. The angle light field conversion function is obtained based on the light field conversion coefficient template of the initial angle and the light field conversion coefficient templates of all swing angles. The gain correction template for the angle to be measured is obtained based on the angle light field conversion function. Gain correction is performed on the bright field image of the angle to be measured using the gain correction template of the angle to be measured, and a corrected image of the angle to be measured is obtained.

2. The method for image correction of a flat panel detector according to claim 1, characterized in that, Processing the bright field image at the initial angle to obtain the gain correction template for the initial angle includes: The bright field image of the initial angle is processed to obtain the grayscale reference value of the initial angle; The gain correction template for the initial angle is obtained based on the grayscale reference value of the initial angle and the bright field image of the initial angle.

3. The method for image correction of a flat panel detector according to claim 2, characterized in that, Acquire bright field images when the X-ray source is irradiated at a certain exposure dose or multiple different exposure doses at an initial angle; When a bright field image is acquired when the X-ray source irradiates a certain exposure dose at an initial angle, a gain correction template for the initial angle is obtained. Bright field images of multiple initial angles are obtained by acquiring images of the X-ray source irradiated with multiple different exposure doses.

4. The method for image correction of a flat panel detector according to claim 3, characterized in that, The light field conversion coefficient template for each swing angle is obtained by processing the bright field images of all the swing angles based on the gain correction template of the initial angle, including: The bright field image of each swing angle is processed according to the gain correction template of the initial angle to obtain the polarized image of each swing angle; The polarized light images at each swing angle are processed to obtain the light field conversion coefficient templates for each swing angle.

5. The method for image correction of a flat panel detector according to claim 4, characterized in that, The bright field image at each swing angle is processed according to the gain correction template of the initial angle to obtain the polarized image at each swing angle, including: A gain correction reference template for the swing angle is determined based on the gain correction template of the initial angle and the bright field image of the swing angle. The polarized light image at each swing angle is obtained based on the gain correction reference template at each swing angle and the bright field image at each swing angle.

6. The method for image correction of a flat panel detector according to claim 5, characterized in that, When there is one gain correction template for the initial angle, the gain correction reference template for each swing angle is determined as follows: (1) Obtain the grayscale reference value of the swing angle (i.e., the grayscale reference value of the bright field image of the swing angle); (2) Obtain the gain correction reference template for the swing angle based on the grayscale reference value of the swing angle and the gain correction template of the initial angle.

7. The method for image correction of a flat panel detector according to claim 5, characterized in that, When there are multiple gain correction templates for the initial angle, the gain correction reference template for each swing angle is determined as follows: (1) Obtain the grayscale reference value of the swing angle (i.e., the grayscale reference value of the bright field image of the swing angle); (2) Determine the gain correction reference template for the swing angle based on the grayscale reference value of the swing angle and the grayscale reference values ​​of multiple initial angles; (3) Obtain the gain correction template for the swing angle based on the grayscale reference value of the swing angle and the gain correction reference template for the swing angle.

8. The method for image correction of a flat panel detector according to claim 6 or 7, characterized in that, The process of processing the polarized image at each swing angle to obtain the light field conversion coefficient template for that swing angle includes: Normalize the polarized image at the swing angle to obtain the normalized gray value of the polarized image. The light field conversion coefficient template for the swing angle is obtained based on the normalized gray value of the polarized image and the corresponding polarized image.

9. The method for image correction of a flat panel detector according to claim 8, characterized in that, The gain correction template for the measured angle is obtained based on the angle light field conversion function, including... Based on the angle light field conversion function, a light field conversion coefficient template for the angle to be measured is obtained; The gain correction template for the angle to be measured is obtained based on the optical field conversion coefficient template for the angle to be measured and the gain correction reference template for the angle to be measured.

10. An apparatus for image correction of a flat panel detector, characterized in that, The method includes a memory, a processor, and a program stored in the memory and executable on the processor, wherein when the processor executes the program, it implements the steps of the flat panel detector image correction method according to any one of claims 1-9.

Images