Empty field image acquisition method, empty field image acquisition device, terminal and computer storage medium

Abstract

The invention provides an empty field image acquisition method, an empty field image acquisition device, a terminal and a computer storage medium, and the method comprises the steps: carrying out the exposure shooting based on a plurality of exposure positions, and obtaining corresponding exposure images; based on the exposure position corresponding to each exposure image, acquiring an image position corresponding to each exposure image; splicing the exposure images with adjacent image positions to obtain an empty field image covering a preset image correction range; wherein the exposure images are combined to cover a preset image correction range. And generating a large-size empty field image through the plurality of exposure images to match a large-size flat panel detector, so as to correct the large-size flat panel detector.

Description

Technical Field

[0001] This application belongs to the field of image processing, and relates to a detector image correction technology, in particular to a method for obtaining an empty field image, an apparatus for obtaining an empty field image, a terminal, and a computer storage medium. Background Art

[0002] Before use, a flat panel detector usually needs to be corrected based on a correction template to eliminate or reduce image quality problems caused by factors such as non-uniformity, noise, and dark current of the detector itself. Generally speaking, the correction template of a flat panel detector needs to be generated based on empty field images at multiple different exposure doses. Therefore, in order to improve the quality of the detection image, it is necessary to obtain an empty field image corresponding to the imaging area of the flat panel detector, so as to generate an accurate and comprehensive correction template to correct the flat panel detector.

[0003] In the prior art, the method for obtaining an empty field template is usually: taking a picture with an exposure light source at a preset exposure dose, so as to obtain an empty field image corresponding to the cover exposure dose. However, due to the limited irradiation range of the exposure light source, the size of the empty field image obtained by this method has certain limitations. Especially for a large-size flat panel detector, the obtained empty field image often cannot cover the imaging area of the flat panel detector, resulting in the inability to generate an accurate and comprehensive correction template, affecting the correction effect of the flat panel detector, and making the detection image quality of the flat panel detector poor.

[0004] Therefore, how to obtain an empty field image that can cover the entire imaging area of the flat panel detector is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of this application is to provide a method for obtaining an empty field image, an apparatus for obtaining an empty field image, a terminal, and a computer storage medium, which are used to solve the problem that the size of the empty field image obtained in the prior art is limited and cannot cover the imaging area of the flat panel detector, resulting in the inability to generate an accurate and comprehensive correction template.

[0006] In a first aspect, this application provides a method for obtaining an empty field image, including:

[0007] Performing exposure shooting based on multiple exposure positions respectively to obtain corresponding exposure images;

[0008] Based on the exposure positions corresponding to the respective exposure images, obtaining the image positions corresponding to the respective exposure images;

[0009] Stitching the respective exposure images adjacent to the image positions respectively to obtain the empty field image covering a preset image correction range;

[0010] Among them, the merged exposure images cover the preset image correction range.

[0011] In an embodiment of the present application, the step of separately splicing the exposure images adjacent in image position to obtain the blank field image covering the preset image correction range includes:

[0012] Based on a preset splicing order, combining the image positions corresponding to the exposure images to obtain two adjacent exposure images as the images to be processed;

[0013] Obtain the overlapping area between the two images to be processed, and use the midline of the overlapping area as the splicing boundary of the two images to be processed respectively;

[0014] Based on the splicing boundary, crop the two images to be processed respectively to obtain the images to be spliced corresponding to the two images to be processed, and splice the two images to be spliced to obtain the spliced image as the new exposure image;

[0015] Based on the new exposure image, combine the splicing order, and re-obtain two adjacent exposure images in image position for splicing until the exposure images are spliced into a total image, and output the total image as the blank field image.

[0016] In an embodiment of the present application, the step of splicing based on the two images to be spliced includes:

[0017] Based on the midline of the overlapping area, obtain the corresponding transitional image;

[0018] Respectively obtain the overlapping areas of the two images to be spliced and the transitional image;

[0019] Based on a preset weight function, perform gray value weighted fusion processing on each pixel point in the overlapping area to splice the two images to be spliced.

[0020] In an embodiment of the present application, the expression of the gray value weighted fusion processing is:

[0021] I = w(x) * I 1 + [1 - w(x)] * I 2 ;

[0022] Wherein, I is the gray value of the pixel point after the gray value weighted fusion processing, w(x) is the preset weight function, I 1 is the gray value of the corresponding pixel point on the transitional image, and I 2 is the gray value of the corresponding pixel point on the image to be spliced.

[0023] In one embodiment of the present application, the weight function is a linear function or a non-linear function.

[0024] In one embodiment of the present application, the expression of the weight function is:

[0025]

[0026] where x is the distance from the pixel point to the midline of the transition image, and r is the width of the transition image.

[0027] In one embodiment of the present application, obtaining the corresponding transition image based on the midline of the overlapping region includes:

[0028] Obtaining a plurality of the transition exposure positions based on the midline of the overlapping region;

[0029] Performing exposure shooting respectively based on each of the transition exposure positions to obtain the corresponding transition exposure images;

[0030] Stitching the transition exposure images respectively based on each of the transition exposure positions to obtain the transition image.

[0031] In a second aspect, the present application provides an empty field image acquisition device, including an exposure image acquisition module, an image position acquisition module, and an exposure image stitching module;

[0032] The exposure image acquisition module is configured to perform exposure shooting respectively based on a plurality of exposure positions to obtain the corresponding exposure images;

[0033] The image position acquisition module is configured to obtain the image positions corresponding to the exposure images based on the exposure positions corresponding to the exposure images;

[0034] The exposure image stitching module stitches the exposure images with adjacent image positions respectively to obtain the empty field image covering a preset image correction range;

[0035] where the exposure images are combined to cover the preset image correction range.

[0036] In a third aspect, the present application provides a terminal, including: a processor and a memory, and the memory is communicatively connected to the processor;

[0037] The memory is configured to store a computer program, and the processor is configured to execute the computer program stored in the memory so that the terminal executes the empty field image acquisition method as described above.

[0038] Fourthly, the present application provides a computer storage medium storing a computer program, which when executed by a processor implements the empty field image acquisition method as described above.

[0039] As described above, the present application provides an empty field image acquisition method, an empty field image acquisition device, a terminal and a computer storage medium. By obtaining multiple exposure images at multiple exposure positions, a large-sized empty field image is stitched together, so that the empty field image can cover the imaging area of the flat panel detector, facilitating the generation of a calibration template required during the calibration of the large-sized flat panel detector, which is beneficial to improving the imaging effect of the flat panel detector and has high industrial application value. Description of the Drawings

[0040] Figure 1 It shows a schematic structural diagram of a flat panel detection system for obtaining an empty field image in the prior art.

[0041] Figure 2 It shows a schematic flow diagram of an empty field image acquisition method according to an embodiment of the present application.

[0042] Figure 3 It shows a schematic diagram of a flat panel detection system for obtaining an empty field image according to an embodiment of the present application.

[0043] Figure 4 It shows a schematic flow diagram of an exposure image stitching method according to an embodiment of the present application.

[0044] Figure 5 It shows a schematic flow diagram of a stitching method for an image to be stitched according to an embodiment of the present application.

[0045] Figure 6 It shows a schematic diagram of a stitching scenario for an image to be stitched according to an embodiment of the present application.

[0046] Figure 7 It shows a schematic flow diagram of a method for obtaining a transition image according to an embodiment of the present application.

[0047] Figure 8 It shows a schematic diagram of the spatial relationship between each transition exposure position and each exposure position according to an embodiment of the present application.

[0048] Figure 9 It shows a schematic structural diagram of an empty field image acquisition device according to an embodiment of the present application.

[0049] Figure 10 It shows a schematic structural diagram of a terminal according to an embodiment of the present application.

[0050] Description of Reference Numerals

[0051] 10 Exposure light source

[0052] 20 Flat panel detector

[0053] 31 Left image to be stitched

[0054] 32 Right image to be stitched

[0055] 41 Exposure image acquisition module

[0056] 42 Image position acquisition module

[0057] 43 Exposure image stitching module

[0058] 50 Terminal

[0059] 51 Processor

[0060] 52 Memory

[0061] 521 Operating system

[0062] 522 Application program

[0063] 53 User interface

[0064] 54 Network interface

[0065] 55 Bus system Detailed implementation manners

[0066] The following uses specific specific examples to illustrate the implementation manners of the present application. Those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in this specification. The present application can also be implemented or applied through other different specific implementation manners. 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 application. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0067] It should be noted that the diagrams provided in the following embodiments only illustrate the basic concept of the present application in a schematic manner. Therefore, only the components related to the present application are shown in the diagrams, rather than being drawn according to the number, shape, and size of the components in actual implementation. The type, quantity, and ratio of each component in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0068] The blank field image is a kind of basic data for generating the correction template of the detector. Usually, it is an image obtained by exposing and photographing with an exposure light source in the absence of the object to be measured. However, due to the influence of spatial factors such as the physical size of the light source and the distance between the light source and the detector, the irradiation range of the exposure light source has certain limitations, resulting in certain limitations in the size of the blank field image. Therefore, the blank field images obtained based on the existing methods often cannot cover the entire imaging area of the detector, especially for large-sized flat panel detectors, which in turn affects the correction effect of the detection image and leads to poor image quality of the obtained images.

[0069] In view of the technical problems existing in the prior art, the following embodiments of the present application provide a method for obtaining a blank field image, a device for obtaining a blank field image, a terminal, and a computer storage medium. By performing exposure shooting at multiple exposure positions respectively to obtain corresponding exposure images, and stitching these exposure images to obtain a blank field image, so as to achieve that the blank field image covers the preset image correction range, and further make the correction template obtained based on the blank field image cover the preset image correction range, so as to realize effective correction within the entire imaging area of the detector, which is beneficial to improving the image quality of the detection image.

[0070] The following embodiments of the present application provide a method for obtaining a blank field image, a device for obtaining a blank field image, a terminal, and a computer storage medium, including but not limited to the application of obtaining the blank field image corresponding to a large-sized flat panel detector. Hereinafter, taking the example of obtaining the blank field image corresponding to a large-sized flat panel detector will be described.

[0071] As Figure 1 shown, the exposure light source 10 irradiates the flat panel detector 20 for exposure, so that the flat panel detector 20 obtains the corresponding blank field image. However, due to the limitation of the shooting environment, the irradiation range of the exposure light source is limited and cannot cover the entire effective imaging area of the flat panel detector, so that the correction template cannot effectively correct the entire effective imaging area of the flat panel detector, which in turn affects the imaging quality of the detector.

[0072] In order to obtain a large-sized blank field image for subsequent correction of the flat panel detector, thereby improving the imaging quality of the detector. Hereinafter, the technical solutions in the embodiments of the present application will be described in detail with reference to the accompanying drawings in the embodiments of the present application.

[0073] As Figure 2 shown, this embodiment provides a method for obtaining a blank field image, including:

[0074] S100, performing exposure shooting based on multiple exposure positions respectively to obtain corresponding exposure images.

[0075] Specifically, the exposure light source 10 performs exposure at each of the exposure positions respectively, so that the flat panel detector 20 obtains the corresponding exposure image.

[0076] Among them, the exposure doses corresponding to the respective exposure images are the same, that is, the exposure light source 10 performs exposure at each of the exposure positions with the same exposure dose. Specifically, corresponding exposure images can be obtained by simultaneously exposing at each of the exposure positions with multiple exposure light sources 10 having the same exposure dose; or corresponding exposure images can be obtained by sequentially exposing at each of the exposure positions with a single exposure light source 10.

[0077] Furthermore, the exposure dose is obtained based on the generation requirements of the calibration template, so as to facilitate generating an accurate calibration template based on the obtained empty field image.

[0078] It should be noted that the multiple obtained exposure images cover a preset image correction range in combination, that is, the combined coverage range of the respective exposure images is greater than or equal to the preset image correction range. Among them, the preset image correction range is used to represent the imaging area of the flat panel detector 20. It should be noted that since the imaging area of the flat panel detector 20 is a continuous area, there is no gap between the respective exposure images, that is, there is an overlapping area with an area greater than or equal to 0 between adjacent exposure images.

[0079] Specifically, the exposure position is a preset position in the direction directly facing the flat panel detector 20. Based on the imaging area of the flat panel detector 20 and in combination with the size of the exposure area of the exposure light source 10 on the flat panel detector 20, the exposure position is designed to enable the respective exposure images to cover the preset image correction range in combination. Among them, the respective exposure positions are evenly distributed, or are unevenly distributed.

[0080] Exemplarily, as Figure 3 shown, exposures are respectively performed based on two of the exposure positions to obtain corresponding exposure areas. The two exposure images cover the flat panel detector 20, and the two exposure images have an overlapping area.

[0081] Based on this, through the respective exposure images, an empty field image that can cover the imaging area of the flat panel detector 20 is obtained, thereby obtaining the corresponding correction template for the flat panel detector 20, which is beneficial to improving the image quality of the detection image.

[0082] S200. Based on the exposure positions corresponding to the respective exposure images, obtain the image positions corresponding to the respective exposure images.

[0083] Specifically, convert the respective exposure positions in the actual shooting space into the image positions of the respective exposure images on the empty field image.

[0084] The image position is used to characterize the position of the exposure image on the empty field image, that is, the position on the flat panel detector 20. Further, when the exposure light source 10 performs exposure at the corresponding exposure position, the irradiation area of the exposure light source 10 on the flat panel detector 20 is the image position corresponding to the exposure image.

[0085] S300. Perform stitching on each of the exposure images adjacent to the image position respectively to obtain the empty field image covering the preset image correction range.

[0086] It should be noted that after stitching each of the exposure images, the coverage range of the empty field image is actually the union of the coverage ranges of each of the exposure images. Since each of the exposure images jointly covers the preset image correction range, based on this, the empty field image covers the preset image correction range, that is, the empty field image covers the imaging area of the flat panel detector 20, so as to assist in generating the imaging area corresponding to the flat panel detector 20 based on the empty field image, and further perform effective correction on the flat panel detector 20 to improve the detection quality of the flat panel detector 20.

[0087] In some alternative embodiments, such as Figure 4 shown, the step of performing stitching on each of the exposure images adjacent to the image position respectively to obtain the empty field image covering the preset image correction range includes:

[0088] S310. Based on the preset stitching order, combine the image positions corresponding to each of the exposure images to obtain two adjacent exposure images as the images to be processed.

[0089] Among them, the stitching order is used to characterize the order of stitching each of the exposure images. Exemplarily, the stitching order is the order from top to bottom and then from left to right, or other orders for sorting images. This embodiment does not make specific limitations here.

[0090] Specifically, if the stitching order is the order from top to bottom and then from left to right, and the image positions of each of the exposure images are arranged in multiple rows and multiple columns, then first stitch each of the exposure images in each column from top to bottom, that is, sequentially obtain two adjacent exposure images up and down as the images to be processed for stitching. When all the images in each column are stitched into one image, at this time the images to be stitched are arranged in one row, and then stitch these images from left to right, that is, sequentially obtain two adjacent exposure images left and right as the images to be processed for stitching, so as to realize the stitching of each of the exposure images.

[0091] Of course, the splicing order can also be other orders, as long as two adjacent exposure images can be obtained based on the splicing order for splicing. This embodiment does not make specific limitations here.

[0092] Splice the exposure images based on the splicing order to facilitate the digitization of the splicing process of each exposure image, thereby effectively improving the convenience of the image splicing process, and further facilitating the improvement of the acquisition efficiency of the empty-field image.

[0093] S320. Obtain the overlapping area between the two images to be processed, and use the midline of the overlapping area as the splicing boundary of the two images to be processed respectively.

[0094] Among them, the overlapping area is the overlapping area between the two images to be processed. Since the exposure images are combined to cover the preset image correction range, the area of the overlapping area between the two images to be processed is greater than or equal to 0. When the boundaries of the two images to be processed coincide, the corresponding overlapping area is 0.

[0095] Further, obtain the midline of the overlapping area between the two images to be processed, and use it as the splicing boundary of the two images to be processed respectively to facilitate subsequent steps.

[0096] Among them, when the spatial relationship between the two images to be processed is a left-right relationship, the midline of the overlapping area is a horizontal midline; when the spatial relationship between the two images to be processed is an up-down relationship, the midline of the overlapping area is a vertical midline.

[0097] S330. Based on the splicing boundary, crop the two images to be processed respectively to obtain the images to be spliced corresponding to the two images to be processed, and splice the two images to be spliced to obtain the spliced image as the new exposure image.

[0098] Among them, the two images to be spliced are two images that have no gaps at the splicing boundary and an overlapping area of 0 after the corresponding images to be processed are cropped along the splicing boundary.

[0099] Specifically, based on the splicing boundary, that is, the midline of the overlapping area, crop the two images to be processed respectively, so that the adjacent boundaries of the cropped images coincide, that is, the boundaries of the images to be spliced coincide. Splice the two images to be spliced to achieve the splicing of two adjacent exposure images.

[0100] Further, use the spliced image as the new exposure image and continue to splice it with other exposure images to finally achieve the splicing of all exposure images.

[0101] S340. Based on the new exposure images, combined with the stitching order, re-acquire two adjacent exposure images in terms of image position for stitching until the exposure images are stitched into a total image, and output the total image as the blank field image.

[0102] Among them, when the exposure images are stitched into a total image, that is, each of the exposure images has completed stitching to form a complete image as the total image. Based on this, the blank field image covering the preset image correction range can be obtained.

[0103] It should be noted that due to the heel effect, the gray values at the stitching boundary of two adjacent images to be stitched are not the same. In order to improve the correction effect of the flat panel detector 20, it is necessary to improve the image quality of the blank field image. Specifically, the gray value change at the stitching boundary of two adjacent images to be stitched needs to have a smooth transition. Based on this, in some alternative embodiments, as Figure 5 shown, the stitching based on the two images to be stitched includes:

[0104] S331. Based on the midline of the overlapping area, obtain the corresponding transition image.

[0105] Specifically, based on the midline of the overlapping area, obtain the transition exposure position, and perform exposure shooting based on the stitching exposure position to obtain the corresponding transition image.

[0106] Among them, the transition exposure position is located at the position directly opposite to the midline of the overlapping area. Therefore, the midline of the transition image actually coincides with the midline of the overlapping area, that is, as Figure 6 shown, the transition image is shown as Figure 6 the dashed box part in, and the two images to be stitched are shown as Figure 6 the solid box parts in. The midline of the transition image actually coincides with the stitching boundary of the two images to be stitched.

[0107] It should be noted that the exposure dose corresponding to the transition image is the same as that of each exposure image to ensure that the exposure dose corresponding to the obtained blank field image is the exposure dose required for generating the correction template.

[0108] Furthermore, the acquisition of the transition exposure position in the above content is named as step S331 for the convenience of those skilled in the art to understand, and actually does not represent the execution sequence and priority of each step. Specifically, in the actual production application process, the transition exposure position and each exposure position are obtained synchronously through design calculation, and each exposure image and the transition image are obtained synchronously through the exposure light source 10 with the same exposure dose.

[0109] S332. Obtain the overlapping regions of the two images to be stitched and the transition image respectively.

[0110] Exemplarily, as Figure 6 shown, the spatial relationship between the two images to be stitched is a left - right relationship. Among them, the image to be stitched on the left is the left image to be stitched 31, and the image to be stitched on the right is the right image to be stitched 32. The overlapping region between the transition image and the left image to be stitched 31 is shown as Figure 6 the slanted part in Figure 6 , that is, the left overlapping region A. The overlapping region between the transition image and the right image to be stitched 32 is shown as

[0111] S333. Based on a preset weight function, perform gray - value weighted fusion processing on each pixel point in the overlapping region to stitch the two images to be stitched.

[0112] Exemplarily, as Figure 6 shown, perform gray - value weighted fusion processing on each pixel point in the left overlapping region A to achieve a smooth transition of the gray - value change at the stitching boundary of the left image to be stitched 31; perform gray - value weighted fusion processing on each pixel point in the right overlapping region B to achieve a smooth transition of the gray - value change at the stitching boundary of the right image to be stitched 32. And because the stitching of the left image to be stitched 31 and the right image to be stitched 32 are both based on gray - value weighted fusion of the transition image, the gray - values at the stitching boundary are the same, thereby improving the stitching effect of the two images to be stitched, making the image quality of the blank - field image better, and being conducive to achieving a better flat - panel detector 20 calibration effect.

[0113] Specifically, the gray - value weighted fusion processing is as follows: for each pixel point in the overlapping region, obtain the gray - values of the corresponding pixel points on the transition image and the image to be stitched respectively, and perform weighted calculation based on the weight function to calculate the gray - value, which is used as the gray - value of this pixel point after the gray - value weighted fusion processing.

[0114] In some optional embodiments, the expression of the gray - value weighted fusion processing is:

[0115] I = w(x)*I 1 +[1 - w(x)]*I 2 ;

[0116] where I is the gray - value of the pixel point after the gray - value weighted fusion processing, w(x) is the preset weight function, I 1 is the gray - value of the corresponding pixel point on the transition image, and I 2 is the gray - value of the corresponding pixel point on the image to be stitched.

[0117] Further, in order to achieve a smooth transition of the gray values, the weight function is a continuous function. Exemplarily, the weight function is a linear function or a non-linear function.

[0118] It should be noted that when the flat panel detector performs exposure shooting, due to the setting of the position of the detector light source, the light distribution is usually brighter in the middle and darker on both sides. When calibrating the flat panel detector 20, calibration needs to be performed based on the actual detection image shooting situation. Correspondingly, the gray value distribution on the obtained empty field image is also higher in the middle gray value and lower on both sides. However, in the method for obtaining the empty field image provided in this embodiment, the edge portions with lower gray values of each of the exposure images may be located in the central region of the obtained empty field image after splicing, that is, the gray value distribution of the empty field image is not good, thereby reducing the calibration effect of the flat panel detector 20.

[0119] Based on this, in some optional embodiments, when performing gray value weighted fusion processing on each pixel point in the overlapping region based on the weight function, by setting the weight function, the gray values of each pixel point in the overlapping region are made close to the gray values in the central region of each of the exposure images, avoiding a lower gray value in the central region of the obtained empty field image, improving the gray value distribution of the obtained empty field image, and further enhancing the calibration effect of the flat panel detector 20.

[0120] Specifically, since the midline of the transition image coincides with the splicing boundary of the two images to be spliced, and since the gray value distribution of the transition image is also higher in the middle gray value and lower on both sides, based on this, in order to improve the gray value distribution of the obtained empty field image, for the pixel points closer to the splicing boundary, the corresponding weight of the transition image is larger, so that the pixel points closer to the splicing boundary have gray values closer to the transition image, that is, the value of the weight function at the splicing boundary is 1 and gradually decreases to 0 in the direction away from the splicing boundary.

[0121] In a specific embodiment, the expression of the weight function is:

[0122]

[0123] where x is the distance from the pixel point to the midline of the transition image, and r is the width of the transition image.

[0124] Of course, the weight function can also be other expressions, as long as the value of the weight function at the splicing boundary is 1 and gradually decreases to 0 in the direction away from the splicing boundary. This embodiment does not make specific limitations here.

[0125] It should be noted that since each of the exposure images may consist of multiple rows and columns, for stitching, generally, the exposure images are first stitched based on columns to obtain the exposure images of a single row, and then stitched based on the exposure images of a single row; or the exposure images are first stitched based on columns to obtain the exposure images of a single row, and then stitched based on the exposure images of a single row. Among them, since the obtained exposure images of a single row or a single column are actually obtained by stitching multiple images, based on this, when stitching two adjacent exposure images based on these exposure images of a single row or a single column, the corresponding two images to be stitched have a long stitching boundary. In order to smoothly transition the gray-scale change at the stitching boundary of the two images to be stitched, in some alternative embodiments, such as Figure 7 shown, obtaining the corresponding transition image based on the midline of the overlapping region includes:

[0126] S3311, obtaining a plurality of the transition exposure positions based on the midline of the overlapping region;

[0127] Among them, the transition exposure position is located at the position directly opposite to the midline of the overlapping region, and after the exposure light source 10 exposes at each of the transition exposure positions respectively, the union of the irradiation ranges covers the stitching boundary of the images to be stitched.

[0128] Each of the transition exposure positions and each of the exposure positions are simultaneously obtained through design calculation and synchronously exposed and photographed by the exposure light source 10.

[0129] Exemplarily, as Figure 8 shown, each of the transition exposure positions and each of the exposure positions form a 3-row and 3-column array. The transition exposure positions are shown as the dotted boxes in the figure, that is, the transition exposure positions 12, 14, 15, 16, and 18 respectively, and the exposure positions are shown as the solid boxes in the figure, that is, the exposure positions 11, 13, 17, and 19 respectively.

[0130] Among them, the exposure images corresponding to the exposure positions 11 and 13 are stitched, and the gray-scale change at the stitching boundary is smoothly transitioned through the transition image corresponding to the transition exposure position 12 to form a new exposure image as the left exposure image; the exposure images corresponding to the exposure positions 17 and 19 are stitched, and the gray-scale change at the stitching boundary is smoothly transitioned through the transition image corresponding to the transition exposure position 18 to form a new exposure image as the right exposure image.

[0131] Further, through the images corresponding to the transition exposure positions 14, 15, and 16, a smooth transition of the gray level change at the splicing boundary between the left exposure image and the right exposure image is achieved.

[0132] S3312. Based on each of the transition exposure positions, perform exposure shooting respectively to obtain corresponding transition exposure images.

[0133] Among them, the exposure dose corresponding to each of the transition images is the same as that of the exposure image, so as to ensure that the exposure dose corresponding to the obtained empty field image is the exposure dose required for generating the calibration template.

[0134] S3313. Based on each of the transition exposure positions, splice each of the transition exposure images to obtain the transition image.

[0135] Exemplarily, as Figure 8 shown, splice the transition exposure images corresponding to the transition exposure positions 14, 15, and 16 to obtain the transition image, so as to achieve a smooth transition of the gray level change at the splicing boundary between the left exposure image and the right exposure image.

[0136] Among them, for the splicing method and principle of each of the transition exposure images, please refer to the splicing method and principle of each of the foregoing exposure images, and no specific elaboration will be made here.

[0137] Based on this, for the method for obtaining an empty field image provided in this embodiment, by obtaining the exposure images corresponding to multiple exposure positions and splicing each of the exposure images, the coverage range of the empty field image is expanded, thereby avoiding that due to the limitation of the shooting environment, the empty field image cannot cover the imaging area of the flat panel detector 20, which is beneficial to improving the calibration effect of the flat panel detector 20. At the same time, this embodiment also improves the splicing effect of each of the exposure images through the transition image, and further improves the image quality of the obtained empty field image, and further improves the calibration effect of the flat panel detector 20.

[0138] The protection scope of the method for obtaining an empty field image described in the embodiments of the present application is not limited to the execution order of the steps listed in this embodiment. Any solution achieved by adding or subtracting steps of the prior art and replacing steps according to the principle of the present application is included in the protection scope of the present application.

[0139] As Figure 9 shown, this embodiment also provides an apparatus for obtaining an empty field image, including an exposure image acquisition module 41, an image position acquisition module 42, and an exposure image splicing module 43;

[0140] An exposure image acquisition module 41, configured to perform exposure shooting based on multiple exposure positions respectively, and acquire corresponding exposure images;

[0141] An image position acquisition module 42, configured to acquire the image positions corresponding to the respective exposure images based on the exposure positions corresponding to the respective exposure images;

[0142] An exposure image stitching module 43, configured to stitch the respective exposure images with adjacent image positions respectively, so as to acquire the blank field image covering a preset image correction range;

[0143] Wherein, the respective exposure images are combined to cover the preset image correction range.

[0144] Based on the same inventive concept, the blank field image acquisition method provided by the embodiments of the present invention can be implemented on the terminal side or the server side.

[0145] As Figure 10 shown, it is a schematic diagram of an optional hardware structure of a terminal provided by an embodiment of the present invention. The terminal 50 may be a mobile phone, a computer device, a tablet device, a personal digital processing device, a factory background processing device, etc. The terminal includes: at least one processor 51, a memory 52, at least one network interface 54, and a user interface 53. Each component in the device is coupled together through a bus system 55. It can be understood that the bus system 55 is used to realize the connection and communication between these components. In addition to the data bus, the bus system further includes a power bus, a control bus, and a status signal bus.

[0146] Wherein, the user interface 53 may include a display, a keyboard, a mouse, a trackball, a click gun, a button, a button, a touchpad, or a touch screen, etc.

[0147] It can be understood that the memory 52 may be a volatile memory or a non-volatile memory, and may also include both a volatile memory and a non-volatile memory. Among them, the non-volatile memory may be a read-only memory (ROM, Read Only Memory), a programmable read-only memory (PROM, Programmable Read-Only Memory), which is used as an external cache. By way of example but not limitation, many forms of RAM are available, such as static random access memory (SRAM, Static Random Access Memory), synchronous static random access memory (SSRAM, Synchronous Static Random Access Memory). The memory characterized by the embodiments of the present invention is intended to include but not limited to these and any other suitable categories of memory.

[0148] The memory 52 in the embodiments of the present invention is used to store various types of data to support the operation of the terminal. Examples of such data include: any executable programs for operating on the terminal 50, such as the operating system 521 and application programs 522; the operating system 521 contains various system programs, such as the framework layer, core library layer, driver layer, etc., for implementing various basic services and processing hardware-based tasks. The application programs 522 may include various application programs, such as a Media Player and a Browser, etc., for implementing various application services. Implementing the empty-field image acquisition method provided by the embodiments of the present invention may be included in the application programs 522.

[0149] The method disclosed in the above embodiments of the present invention can be applied to the processor 51 or implemented by the processor 51. The processor 51 may be an integrated circuit chip with signal processing capabilities. During implementation, the steps of the above method can be completed by the integrated logic circuit in hardware in the processor 51 or instructions in software form. The above processor may be a general-purpose processor, a digital signal processor (DSP), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The processor 51 can implement or execute the various methods, steps, and logic block diagrams disclosed in the embodiments of the present invention. The general-purpose processor 51 may be a microprocessor or any conventional processor, etc. Combining the steps of the accessory optimization method provided by the embodiments of the present invention can be directly embodied as being completed by a hardware decoding processor, or by a combination of hardware and software modules in the decoding processor. The software module may be located in a storage medium, and this storage medium is located in the memory. The processor reads the information in the memory and combines its hardware to complete the steps of the foregoing method.

[0150] In an exemplary embodiment, the terminal 50 may be one or more application-specific integrated circuits (ASICs), DSPs, programmable logic devices (PLDs), complex programmable logic devices (CPLDs) for executing the foregoing method.

[0151] The embodiments of the present invention also provide a computer-readable storage medium, on which a computer program is stored, and when the program is called by a processor, it implements the empty-field image acquisition method provided by the present invention.

[0152] Among them, the computer-readable storage medium can be a tangible device that can hold and store instructions used by the instruction execution device. The computer-readable storage medium can be, for example, (but is not limited to) an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the above. More specific examples (non-exhaustive list) of the computer-readable storage medium include: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disk read-only memory (CD-ROM), digital versatile disk (DVD), memory stick, floppy disk, and mechanical encoding devices.

[0153] The computer-readable program characterized herein can be downloaded from the computer-readable storage medium to various computing / processing devices, or downloaded to an external computer or external storage device through a network, such as the Internet, a local area network, a wide area network, and / or a wireless network. The network adapter or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards the computer-readable program instructions for storage in the computer-readable storage medium in each computing / processing device.

[0154] In summary, in this application, by stitching multiple said exposure images, a blank field image that can cover the preset image correction range is obtained, thereby generating a correction template that can correct the imaging area of the flat panel detector, thereby indirectly improving the image quality of the detection image obtained by the flat panel detector. And when stitching each said exposure image, the stitching effect is improved through the said transition image, thereby effectively improving the image quality of the blank field image, and further improving the correction effect of the flat panel detector, which has high industrial application value.

[0155] The descriptions of the processes or structures corresponding to the above respective drawings have their own emphases. For parts not detailed in a certain process or structure, reference can be made to the relevant descriptions of other processes or structures.

[0156] The above embodiments are only illustrative of the principles and effects of this application, and are not used to limit this application. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed in this application should still be covered by the claims of this application.

Claims

1. A method for acquiring an empty field image, comprising: Perform exposure shooting based on multiple exposure positions respectively to obtain corresponding exposure images; Based on the exposure position corresponding to each of the exposure images, acquiring the image position corresponding to each of the exposure images; Separately splicing the exposure images adjacent to each other in the image position to obtain the empty field image covering a preset image correction range; Wherein, each of the exposure images is combined to cover the preset image correction range.

2. The method for acquiring an empty field image according to claim 1, characterized in that: The step of respectively splicing the exposure images adjacent to each other in the image position to obtain the empty field image covering a preset image correction range includes: Based on a preset stitching order and in combination with the image positions corresponding to the exposure images, two adjacent exposure images are acquired as images to be processed; Acquire an overlapping area between the two images to be processed, and use the midlines of the overlapping area as the stitching boundaries of the two images to be processed; Based on the stitching boundary, the two images to be processed are respectively cropped to obtain images to be stitched corresponding to the two images to be processed, and the two images to be stitched are stitched to obtain a stitched image as the new exposure image; Based on the new exposure image and in combination with the stitching order, two exposure images with adjacent image positions are reacquired for stitching until the exposure images are stitched into a total image, and the total image is output as the empty field image.

3. The method for acquiring an empty field image according to claim 2, characterized in that: The stitching based on the two images to be stitched includes: Based on the center line of the overlapping area, acquiring a corresponding transition image; Respectively obtaining overlapping areas of the two images to be stitched and the transition image; Based on a preset weight function, grayscale value weighted fusion processing is performed on each pixel in the overlapped area to splice the two images to be spliced.

4. The method for acquiring an empty field image according to claim 3, characterized in that: The expression of the gray value weighted fusion processing is: I=w(x)*I1+[1-w(x)]*I2; Among them, I is the gray value of the pixel after performing the gray value weighted fusion processing, w(x) is the preset weight function, I1 is the gray value corresponding to the pixel on the transition image, and I2 is the gray value corresponding to the pixel on the image to be spliced.

5. According to the empty field image acquisition method of claim 4, the weight function is a linear function or a nonlinear function.

6. The method for acquiring an empty field image according to claim 5, characterized in that: The expression of the weight function is: Wherein, x is the distance from the pixel point to the center line of the transition image, and r is the width of the transition image.

7. The method for acquiring an empty field image according to claim 1, characterized in that: The acquiring a corresponding transition image based on the center line of the overlapping area includes: Based on the center line of the overlapping area, acquiring a plurality of transition exposure positions; Perform exposure shooting based on each of the transition exposure positions to obtain a corresponding transition exposure image; Based on each of the transition exposure positions, each of the transition exposure images is spliced ​​to obtain the transition image.

8. An empty field image acquisition device, characterized in that: It includes an exposure image acquisition module, an image position acquisition module and an exposure image stitching module; The exposure image acquisition module is used to perform exposure shooting based on multiple exposure positions respectively to acquire corresponding exposure images; The image position acquisition module is used to acquire the image position corresponding to each of the exposure images based on the exposure position corresponding to each of the exposure images; The exposure image stitching module stitches the exposure images adjacent to each other in position to obtain the empty field image covering a preset image correction range; Wherein, each of the exposure images is combined to cover the preset image correction range.

9. A terminal, characterized in that: include: A processor and a memory, wherein the memory is communicatively connected to the processor; The memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory, so that the terminal executes the empty field image acquisition method according to any one of claims 1 to 7.

10. A computer storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the empty field image acquisition method according to any one of claims 1 to 7 is implemented.

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