X-ray-based scanning imaging system and scanning imaging method

Abstract

The invention discloses an X-ray-based scanning imaging system and method, and the system comprises an X-ray machine target spot which is used for generating an X-ray beam; the collimator is used for modulating the X-ray beam into a linear light beam; when the linear light beam irradiates an object, scanning an object image column by column, and when pixel points in the same column are scanned, no adjacent pixels are overlapped in each scanning; and the detector is used for receiving an X-ray signal scattered by the chopping device through the scanned object. According to the scheme, the imaging method is redesigned by taking the algorithm as the core according to the physical principle of image degradation, and the purpose of improving the performance is achieved.

Description

Technical Field

[0001] The present application relates to the field of X-ray detection technology, and in particular to an X-ray-based scanning imaging system and a scanning imaging method. Background Art

[0002] The X-ray backscatter imaging technology that is widely used at present is the flying spot scanning technology. There are some differences in the specific implementation methods, such as flying disc, chopper wheel, column cylinder, etc., but the essence is to achieve single-point continuous scanning.

[0003] The problem with the existing technology is that during the continuous scanning integral imaging process, the scanning area on the object under test continues to change, and the image quality after imaging is degraded. Therefore, the imaging method design needs to be combined with advanced image processing algorithms, such as sparse imaging, super-resolution imaging, etc., otherwise it will be difficult to improve performance. Summary of the invention

[0004] In view of the above technical problems, the present invention designs an X-ray based scanning imaging system and an imaging method thereof.

[0005] An X-ray based scanning imaging system, comprising:

[0006] X-ray machine target, used to produce X-ray beam;

[0007] A collimator, used to modulate the X-ray beam into a linear beam;

[0008] When the linear light beam irradiates the object, the object image is scanned row by row, and when the pixels in the same row are scanned, there is no overlap of adjacent pixels;

[0009] The detector is used to receive the X-ray signal scattered from the chopper device through the scanned object.

[0010] Optionally, a chopping device is further included, wherein the chopping device is provided with a plurality of groups of light holes, each group of light holes corresponds to a column of images, and a collimator is arranged between the target point of the X-ray machine and the chopping device, so that during the movement of the chopping device, at a position of the chopping device, when a linear light beam passes through the light-transmitting hole of the chopping device, it only passes through one light hole corresponding to the same row of images, and as the chopping device moves, the linear light beam passes through the light holes of the chopping device corresponding to consecutive rows of images in turn after a certain interval.

[0011] Optionally, the light holes in each group are arranged in a stepped manner, the height of the light holes projected onto the scanned object is an integer multiple of the height of a pixel, and there is at least one row of opaque areas as intervals between adjacent light holes in each group.

[0012] Optionally, the chopper device is divided into at least two sub-areas, each sub-area includes a group of light holes, the chopper device is in a circular ring shape, and the outgoing linear light beam of the collimator is along the radius direction of the circular ring.

[0013] Optionally, the chopper device is in a circular shape, and is provided with a plurality of light-transmitting positioning slits along the radial direction, the positioning slits divide the chopper device into a plurality of areas, and the light-transmitting holes in each area are arranged in a stepped manner from the outer circumference to the inner circumference.

[0014] Optionally, there is at least one row of opaque areas as intervals between adjacent light-through holes of the chopping device, and the rows occupied by different groups of light-through holes are staggered.

[0015] Optionally, the height of each light hole projected onto the scanned object is at least equal to twice the height of a pixel, and the rows occupied by light holes of different groups overlap.

[0016] Optionally, the chopper device is in a circular shape, the light holes in the same group are distributed on the same radius, and there is a gap between adjacent light holes in the same group; the height of the light holes projected onto the scanned object is an integer multiple of the height of a pixel.

[0017] Optionally, the chopping device is divided into at least two sub-areas along the circumference, each sub-area includes a group of light holes, and the outgoing light beam of the collimator is along the tangent direction of the inner circle of the ring.

[0018] Optionally, the X-ray beam generated by the X-ray machine target is pulsed; in the time period corresponding to each column of pixel points, there are beam pulses with the same interval, and the pulse interval of the beam pulses is greater than the pulse width; in the time period corresponding to each column, the beam pulses scan a column of pixel points row by row.

[0019] Optionally, the width and interval of the scanning light beam pulses corresponding to different columns of pixels are the same, but the arrival time of the start pulse is sequentially moved backward by 1 / n time intervals, where n is a positive integer.

[0020] A scanning imaging method based on X-rays, comprising:

[0021] include:

[0022] Produce an X-ray beam through an X-ray machine target;

[0023] The X-ray beam is modulated into a linear beam by a collimator;

[0024] The linear light beam is used to illuminate the object, and the image of the object is scanned row by row, and when the pixel points in the same row are scanned, there is no pixel overlap between each scan;

[0025] The detector receives the X-ray signal scattered from the chopper through the scanned object.

[0026] Optionally, a chopping device is provided;

[0027] The X-ray beam scans in the direction of the row;

[0028] The X-ray beam passes through the first light hole of a group of light holes of the chopper device to scan the first group of pixel points of the first column of the image of the object; the chopper device is rotated or moved; the X-ray beam passes through the second light hole of the group of light holes to scan the second group of pixel points of the first column of the image of the object; until the X-ray beam passes through the last light hole of the first group of light holes to scan the last group of pixel points of the first column of the image of the object; thus, the scanning of the first column of the image is completed;

[0029] Adjusting the relative position between the chopper device and the target point of the X-ray machine, and then performing the next row of scanning;

[0030] receiving, by a detector, an X-ray signal emitted from a chopping device through a scanning sample;

[0031] The relevant data are processed to complete the correction.

[0032] Optionally, adjacent light holes of the chopping device are spaced apart in the direction of the column, and rows where different groups of light holes are located are staggered; in scanning of the same column of object images, a group of pixels are spaced apart between the pixels scanned each time, and after all images are scanned, the step of performing an interpolation algorithm to calculate the images of the pixels that have not been scanned at the intervals is also included.

[0033] Optionally, the height of each light hole projected onto the scanned object is at least equal to twice the height of a pixel, and the heights of different groups of light holes overlap in the row direction; in the scanning of the same column of object images, when a group of pixels scanned each time includes multiple pixels, the step of extracting sub-pixel information and using a projection iteration method or an AI training method to achieve high-resolution reconstruction is also included.

[0034] Optionally, the X-ray beam scans the object along the row direction, and the X-ray beam generated by the target point of the X-ray machine is pulsed; the image of the first column of pixel points of the object is scanned in a first time period; the image of the second column of pixel points of the object is scanned in a second time period; and so on until the image scanning of all columns is completed; in the time period corresponding to each column of pixel points, there are light beam pulses with the same interval, and the pulse interval of the light beam pulses is greater than the pulse width; in the time period corresponding to each column, the light beam pulses scan a column of pixel points row by row.

[0035] Optionally, the width and interval of the scanning light beam pulses corresponding to different columns of pixels are the same, but the arrival time of the start pulse is sequentially moved backward by 1 / n time intervals, where n is a positive integer.

[0036] The advantages of the present invention are:

[0037] 1.) Improve resolution. The solution of the present invention removes the smoothing effect in continuous scanning, retains the original detail information, and achieves higher resolution by combining staggered scanning and post-processing algorithms;

[0038] 2.) Improve the signal-to-noise ratio. This solution can effectively improve the signal-to-noise ratio and improve the penetration index to a certain extent;

[0039] 3.) Improve the speed. The sparse sampling method in this scheme can improve the scanning speed;

[0040] 4.) Reduce the dose. The sparse sampling method in this scheme can reduce the absorbed dose of the object being inspected. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0042] Figure 1 It is a schematic diagram of an existing scatter imaging continuous imaging scanning system;

[0043] Figure 2 It is a schematic diagram of an existing perspective imaging continuous imaging scanning system;

[0044] Figure 3 is a schematic diagram of an X-ray scanning imaging system according to a first embodiment of the present invention;

[0045] Figure 4a-4b is a schematic diagram of an X-ray scanning imaging system according to a second embodiment of the present invention;

[0046] Figure 4b is a schematic diagram of an X-ray scanning imaging system according to a third embodiment of the present invention;

[0047] Figure 5 is a schematic diagram of an X-ray scanning imaging system according to a fourth embodiment of the present invention;

[0048] Figure 6 Schematic diagram of an X-ray scanning imaging system according to a fifth embodiment of the present invention;

[0049] Figure 7 Schematic diagram of an X-ray beam generated by an X-ray machine target point according to a sixth embodiment of the present invention;

[0050] Figure 8 Schematic diagram of the X-ray beam generated by the X-ray machine target point and the image acquisition position in one embodiment of the present invention. DETAILED DESCRIPTION

[0051] As described in the background, both backscatter imaging and perspective imaging continuous scanning in the prior art have the problem of image degradation. The inventors believe that the reasons are as follows:

[0052] First, for backscatter imaging, such as Figure 1 As shown in Figure 2, the flying spot scanning process is as follows: Figure 1 As shown, it is different from static imaging. For example, when collecting the signal at position '2' shown in the right figure, the signal accumulation starts when the ray covers position '1' and ends when the ray completely covers position '2'. The obtained signal is the weighted average of position '1' and position '2'. If static sampling is used, the ray always covers position '2', and the collected signal is the real signal at position '2'. Figure 1 In the image, the spot size is the same as the size of a pixel. In many cases, the spot may cover several pixels, which is equivalent to multiple point smoothing. Therefore, on the one hand, the real signal is smoothed: due to the continuous movement during the integration process, for one pixel after imaging, its signal size is the weighted average of the real signals of the N pixels before and after, the effective signal is smoothed, and the detail information is lost.

[0053] Secondly, the noise signal is mainly composed of statistical fluctuation noise, shot noise, thermal noise, etc. These noises have nothing to do with whether the signal is collected statically or not. For example, fluctuation noise is related to the total number of photons N detected by the detector (the size of fluctuation noise is √N), and has nothing to do with the scanning mode (static or continuous movement). For another example, thermal noise is only related to the electronic part of the detection system. Therefore, this continuous integration scanning method makes the real signal weighted and smoothed, while the noise is not smoothed, and it is increased due to the introduction of invalid signals. The final effect is that the effective signal is reduced, the noise is increased, and the signal-to-noise ratio (SNR) is significantly reduced. Therefore, signal smoothing in the sampling process is essentially different from smoothing in signal post-processing. In signal post-processing, the filtering operation smoothes the real signal and noise at the same time; while in continuous integration sampling, only the real signal is smoothed, the effective signal becomes smaller, and the details are lost, while the noise size is related to the total signal size obtained by the detection system. Since invalid signals are also superimposed on the total signal, the noise increases. Compared with static imaging: the real signal is smoothed, the effective value (DC component removed) decreases, details are lost, while the noise signal increases, and the final signal-to-noise ratio is significantly reduced.

[0054] Second, for perspective imaging, see Figure 2 ,This continuous scanning imaging method is similar to the backscattered flying spot scanning ,imaging, and the same reasons lead to the loss of detail information and ,decrease in signal-to-noise ratio.

[0055] After the above research and analysis, the present invention provides an X-ray based scanning imaging system, comprising:

[0056] X-ray machine target, used to produce X-ray beam;

[0057] A collimator, used to modulate the X-ray beam into a linear beam;

[0058] When the linear light beam irradiates the object, the object image is scanned row by row, and when the same row of pixels is scanned, there is no pixel overlap between each scan;

[0059] The detector is used to receive the X-ray signal scattered from the chopper device through the scanned object.

[0060] The present invention also provides an X-ray based scanning imaging method, comprising:

[0061] Produce an X-ray beam through an X-ray machine target;

[0062] The X-ray beam is modulated into a linear beam by a collimator;

[0063] The linear light beam is used to illuminate the object, and the image of the object is scanned row by row, and when the pixel points in the same row are scanned, there is no pixel overlap between each scan;

[0064] The detector receives the X-ray signal scattered from the chopper through the scanned object.

[0065] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of this application.

[0066] Embodiment 1

[0067] The present application embodiment provides an X-ray based scanning imaging system, such as Figure 3 As shown, 100 is a light source, which is an X-ray machine target in this embodiment. In this embodiment, flying spot scanning is taken as an example. A collimator 110 is arranged behind the X-ray machine target to modulate the X-ray beam into a linear beam; a chopper 120 is arranged behind the collimator 110, and a scanning sample 130 and a detector 140 are arranged behind the chopper 120. In this embodiment, the detector is a backscatter detector.

[0068] In this embodiment, the chopper device is provided with a plurality of groups of light holes, each group of light holes corresponds to a column of images, and a collimator is arranged between the X-ray machine target and the chopper device, so that when the chopper device moves, when the linear light beam passes through the light holes, it only passes through one light hole in the row direction of the chopper device, and as the chopper device moves, it passes through the light holes of consecutive rows of the chopper device in turn, and there is a gap between the light holes passing through adjacent rows.

[0069] In one embodiment, the light holes in each group of the chopper device are arranged in a stepped manner, the height of the light holes projected onto the scanned object is an integral multiple of the height of a pixel, and adjacent light holes in each group are spaced apart in the column direction. Specifically, each row has a light hole, the height of the light hole is the same as the height of a pixel, and the columns where the light holes are located are spaced apart. The chopper device is rectangular, and the light holes are distributed along the diagonal.

[0070] In the flying spot scanning method of the present invention to remove the smoothing effect, the core design is to make the direction of the light-through holes discontinuous, with gaps between them, such as Figure 3 The data collection process is shown in the right figure. For example, the signal at position '1' is collected from the beginning to the end through the process (1)-(5) in the figure. Because the light holes are not continuous along the column direction, that is, there are gaps between them, the signal at position '2' is not superimposed, so the collected data has no smooth accumulation effect. Figure 3 If the chopper device is divided into an area [m,n] with m rows and n columns corresponding to the pixel points, then the first light hole is located in the area [1,1], the second light hole is located in the area [2,3], the third light hole is located in the area [3,5]... and so on. That is to say, each row has a light hole, and only odd-numbered columns or even-numbered columns have light holes, that is, there are gaps between the columns where the light holes are located, and they are distributed at intervals.

[0071] refer to Figure 3 On the right side of the figure, there is a diagram of smooth scanning. When the scanning starts, the flying spot X-ray beam is emitted, and the chopper moves along its row direction. In state (1), the light hole does not overlap with pixel 1, so the flying spot cannot pass through the light hole. From state (2) to state (4), the light hole gradually overlaps with pixel 1, and the flying spot passes through the light hole to scan pixel 1. In state (5), pixel 1 is scanned. Due to continuous scanning, the flying spot falls in the light-proof area of ​​the gap between the holes, so it cannot be scanned. It is not until the light hole in the next column gradually overlaps with pixel 2 that pixel 2 can be scanned again. In this way, during the signal acquisition process of pixel 1, no signals from other pixels are superimposed.

[0072] Compared with the traditional scanning method with smoothing effect, the real signal is not smoothed, the effective signal value is relatively large, and the absolute value of the noise is about the original times (because the total signal is about 1 / 2 of the original). Figure 3 The figure only shows the case where the size of the light hole covers one pixel. However, in many cases, the existing technology will cover several pixels, the smoothing effect is more serious, and the noise difference is greater. This solution improves the signal-to-noise ratio significantly.

[0073] Embodiment 2

[0074] like Figure 4a As shown, this embodiment is different from the first embodiment in that the chopping device is divided into at least two sub-areas along the row direction, for example Figure 4a The four sub-areas shown in the figure each contain a group of light holes, the chopper device is in a circular ring shape, the column direction refers to the circumferential direction, the row direction refers to the radial direction, and the outgoing linear light beam of the collimator is along the radial direction of the ring. In one embodiment, the chopper device is divided into a plurality of areas, and the light holes in each area are arranged in a stepped manner from the outer circumference to the inner circumference. Figure 4a If the chopper device is divided into n columns distributed along the circumference and m rows distributed along the radius, there are regions [m,n], then the first light hole in the first sub-region is located in region [1,1], the second light hole is located in region [2,3], the third light hole is located in region [3,5]... and so on. Similarly, the second sub-region, the third sub-region, and the fourth sub-region are also distributed in the same way. That is to say, in each sub-region, each row has a light hole, and only odd-numbered columns or even-numbered columns have light holes, that is, there are gaps between the columns where the light holes are located, and they are distributed at intervals.

[0075] In this embodiment, when scanning starts, the flying spot X-ray beam is emitted, and the chopper rotates around a circle. The starting point positioning slit is the starting position of the scan, and is also the start of a sub-area. The light holes at the next positioning slit are arranged again from the first row, thereby entering the scanning of the next column of images.

[0076] In some embodiments, Figure 4a The application method in which the linear light beam emitted by the collimator coincides with the radial direction, and the chopper device is shown in the middle figure, wherein the long gap can be used as a mark for judging the starting position.

[0077] Embodiment 3

[0078] like Figure 4b As shown, in other embodiments, the chopper device of the X-ray-based scanning imaging system is in the shape of a ring, and the light holes in the same group are distributed on the same radius, and there is a gap between adjacent light holes in the same group; the height of the light holes projected onto the scanned object is an integer multiple of the height of a pixel point. Among them, the chopper device is divided into at least two sub-areas along the row direction, each sub-area contains a group of light holes, and the outgoing linear beam of the collimator is along the tangent direction of the inner circle of the ring. That is, the collimator is an eccentric design, along the tangent direction of the inner circle.

[0079] Embodiment 4

[0080] refer to Figure 5The difference between this embodiment and the above-mentioned embodiment is that the chopper device is divided into several sub-areas along the column direction, taking a rectangle as an example, and the light holes in each sub-area are arranged in a stepped manner, and the rows and columns where they are located are distributed at intervals, and the rows where the light holes in different sub-areas are located are staggered. Figure 5 If the chopping device is divided into an area [m, n] with m rows and n columns corresponding to the pixel points, then in this embodiment, the first sub-area includes the 1st to 12th columns of the 1st row, and the second sub-area includes the 13th to 24th columns of the 1st row.

[0081] In the first sub-area the light opening is located at:

[0082] Area [1,1], [3,3], [5,5], [7,7], [9,9], [11,11],

[0083] In the second sub-area the apertures are located at:

[0084] Areas [2,13], [4,15], [6,17], [8,19], [10,21], [12,23], and so on, that is, each row has a light hole, and only odd-numbered columns or even-numbered columns have light holes, that is, there are gaps between the columns where the light holes are located, and they are distributed at intervals.

[0085] Therefore, there are intervals between the columns of light-through holes on the left and right, and the row where the starting light-through hole of each sub-region is located is offset.

[0086] In the application of this scheme, the chopper device moves relative to the light source in the column direction, so that after scanning the sample, the image acquisition position is shown on the right.

[0087] In some embodiments, the chopping device can be further divided into more sub-areas.

[0088] In this embodiment, a sparse scanning method is used. Figure 5 As shown, the left and right intervals are used for smoothing, where the upper and lower intervals are sparse sampling, each column is collected at intervals, and the next column is misaligned with it. Taking the misalignment of an entire pixel as an example, the effect is as shown in the right figure. The white dot corresponds to the scan point of the object being inspected, and the pixel value of the black dot position can be calculated using an ordinary interpolation algorithm. The AI ​​training method has a better effect. This solution can reduce the dose and increase the speed. The core design idea is as follows Figure 5 .

[0089] In some embodiments, reference may also be made to Figure 3 , Figure 4a , 4b The chopping device is arranged in a ring shape.

[0090] Embodiment 5

[0091] refer to Figure 6In this embodiment, the difference from the above-mentioned embodiment is that the chopping device is divided into several sub-areas along the row and column directions, taking a rectangle as an example, and the light holes in each sub-area are arranged in a stepped manner. In each sub-area, the height of the light holes is greater than the height of a pixel, and the light holes in different sub-areas overlap in height in the row direction. For details, see Figure 6 In this embodiment, the chopper device is divided into three sub-areas. If the chopper device is divided into an area [m,n] with m rows and n columns corresponding to the pixel points, then in this embodiment, the first sub-area includes the 1st to 12th columns of the 1st row, the second sub-area includes the 13th to 24th columns of the 1st row, and the third sub-area includes the 25th to 34th columns of the 1st row. Since the height occupied by each light hole in this embodiment is greater than the height of a pixel point, in this embodiment, the height occupied by two pixel points is taken as an example:

[0092] In the first sub-area the light opening is located at:

[0093] Area [1-2, 1], [3-4, 3], [5-6, 5], [7-8, 7], [9-10, 9], [11-12, 11];

[0094] In the second sub-area the apertures are located at:

[0095] Regions [1.25-2.25, 1], [3.25-4.25, 3], [5.25-6.25, 5], [7.25-8.25, 7], [9.25-10.25, 9], [11.25-12.25, 11];

[0096] In the third sub-area the aperture is located at:

[0097] Area [1.5-2.25,1], [3.5-4.25,3], [5.5-6.5,5], [7.5-8.25,7], [9.5-10.5,9],

[0098] [11.5-12.5,11].

[0099] By analogy, every two rows have a light hole, and the light hole occupies the height of two pixels, so that every two rows of light holes are continuous, that is, every row has a light hole, and only odd-numbered columns or even-numbered columns have light holes, that is, there are gaps between the columns where the light holes are located, and they are distributed at intervals. In this solution, the image acquisition position is shown in the figure on the right.

[0100] This embodiment adopts a super-resolution scanning method, such as a backscatter detector, such as Figure 6As shown, the height position of each column is misaligned, and the pixels are misaligned by 1 / n in a cycle. Taking n as 4 as an example, the acquisition effect is shown in the figure on the right. The pixel point is large, the signal-to-noise ratio is high, and the scanning speed is fast, but the resolution is low. This solution extracts sub-pixel information by misaligning the pixels collected in each column, and then cooperates with the post-processing algorithm to achieve high-resolution reconstruction. The specific algorithm can be trained by projection iteration method or AI training method. The above only explains the core idea of ​​this solution.

[0101] In some embodiments, reference may also be made to Figure 3 , Figure 4a , 4b The chopper device is matched to the disc by this method.

[0102] In some embodiments, the chopping device can be further divided into more sub-areas.

[0103] Embodiment 6

[0104] In this embodiment, there is no need to set a chopping device, such as Figure 7 As shown, the X-ray beam generated by the X-ray machine target is pulsed; in the time period corresponding to each column of pixel points, there are beam pulses with the same interval, and the pulse interval of the beam pulses is greater than the pulse width; in the time period corresponding to each column, the beam pulses scan a column of pixel points row by row.

[0105] Specifically, the pulsed light source can be combined with the newly developed carbon nanotube technology and ordinary flying spot scanning to achieve smoothing, sparse sampling and super-resolution scanning. The principle is as follows:

[0106] Desmoothing principle: Since the time ΔT of a pulse of a pulsed light source is very small compared to the interval T of the next pulse, when scanning a pixel point, it can be approximately considered that no movement occurs. When it moves to the next position, another pulse beam is sent to scan. In this way, there is no superposition effect between the previous and next scanned points, thereby achieving a desmoothing effect.

[0107] In one embodiment, if Figure 8 As shown, the width and interval of the scanning light beam pulses corresponding to different columns of pixels are the same, but the arrival time of the starting pulse is shifted backward by 1 / n (n is a positive integer) time intervals.

[0108] The principle is as follows: using the sparse sampling principle, the pulse starting point positions of each column are offset, and the pulse interval is increased to achieve the purpose of sparse sampling. For example, there is a time difference between the starting pulses of the first column scan and the second column scan in the figure, so that the effect of the image acquisition position is as shown in the figure.

[0109] Accordingly, in one embodiment, the X-ray based scanning imaging method comprises the steps of: generating an X-ray beam through an X-ray machine target point;

[0110] The X-ray beam is modulated into a linear beam by a collimator;

[0111] The linear light beam is used to illuminate the object, and the image of the object is scanned row by row, and when the same row of pixels is scanned, there is a time interval between each scan;

[0112] The detector receives the X-ray signal scattered from the chopper through the scanned object.

[0113] In one embodiment, it further includes:

[0114] Set up the chopping device;

[0115] The X-ray beam scans in the direction of the row;

[0116] The X-ray beam passes through the first light hole of a group of light holes of the chopper device to scan the first group of pixel points of the first column of the image of the object; the chopper device is rotated or moved; the X-ray beam passes through the second light hole of the group of light holes to scan the second group of pixel points of the first column of the image of the object; until the X-ray beam passes through the last light hole of the first group of light holes to scan the last group of pixel points of the first column of the image of the object; thus, the scanning of the first column of the image is completed;

[0117] Adjusting the relative position between the chopper device and the target point of the X-ray machine, and then performing the next row of scanning;

[0118] receiving, by a detector, an X-ray signal emitted from a chopping device through a scanning sample;

[0119] The relevant data are processed to complete the correction.

[0120] In one embodiment, adjacent light holes of the chopping device are spaced apart in the direction of the column, and rows where different groups of light holes are located are staggered; in scanning of the same column of object images, a group of pixels are spaced apart between the pixels scanned each time, and after all images are scanned, the step of performing an interpolation algorithm to calculate the images of the pixels that have not been scanned at the intervals is also included.

[0121] In one embodiment, the height of each light hole projected onto the scanned object is at least equal to twice the height of a pixel, and the heights of different groups of light holes overlap in the row direction; in the scanning of the same column of object images, when a group of pixels scanned each time includes multiple pixels, the step also includes: extracting sub-pixel information and using a projection iteration method or an AI training method to achieve high-resolution reconstruction.

[0122] In one embodiment, an X-ray beam scans an object along a column direction, and the X-ray beam generated by the target point of the X-ray machine is pulsed; an image of a first column of pixel points of the object is scanned in a first time period; an image of a second column of pixel points of the object is scanned in a second time period; and so on until the image scanning of all columns is completed; in a time period corresponding to each column of pixel points, light beam pulses have the same interval, and the pulse interval of the light beam pulses is greater than the pulse width; in a time period corresponding to each column, the light beam pulses scan a column of pixel points row by row.

[0123] In one embodiment, the width and interval of the scanning light beam pulses corresponding to different columns of pixels are the same, but the arrival time of the starting pulse is sequentially moved backward by 1 / n (n is a positive integer) time intervals.

[0124] In the process of conventional flying spot scanning imaging, the device and the scanned object move relative to each other, and the final imaging produces motion blur. Although the image can be restored to a certain extent through the post-processing algorithm, the detail information is still lost, and it is also difficult to eliminate the noise caused by the additional superimposed signal during the blurring process. By changing the imaging method, removing the motion blur and the increased noise, the image detail information and the signal-to-noise ratio are finally improved. Appropriate adjustment of this scheme can achieve the purpose of increasing the scanning speed, improving the resolution, reducing the dose, and reducing the penumbra effect caused by non-point light sources. The scheme of the present invention is based on the physical principle of image degradation, and with the algorithm as the core, the imaging method is redesigned to achieve the purpose of performance improvement.

[0125] The engineering significance of the technical solution of the present invention:

[0126] 1.) Improve resolution. The solution of the present invention removes the smoothing effect in continuous scanning, retains the original detail information, and achieves higher resolution by combining staggered scanning and post-processing algorithms;

[0127] 2.) Improve the signal-to-noise ratio. This solution can effectively improve the signal-to-noise ratio and improve the penetration index to a certain extent;

[0128] 3.) Improve the speed. The sparse sampling method in this scheme can improve the scanning speed;

[0129] 4.) Reduce the dose. The sparse sampling method in this scheme can reduce the absorbed dose of the object being inspected.

[0130] This can bring the following beneficial effects:

[0131] 1. Improved performance indicators can enhance competitiveness and expand application scenarios, such as those that require high-resolution scenes or scenes that require deep penetration, etc.

[0132] 2. Speed ​​increase can improve the utilization efficiency of equipment;

[0133] 3. Reduce the dose, suitable for low-dose scanning scenarios, while reducing protection costs.

[0134] The above describes the illustrative specific implementation modes of the present invention to facilitate the understanding of the present invention by those skilled in the art, and it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

Claims

1. An X-ray based scanning imaging system, characterized in that: include: X-ray machine target, used to produce X-ray beam; A collimator, used to modulate the X-ray beam into a linear beam; When the linear light beam irradiates the object, the object image is scanned row by row, and when the pixels in the same row are scanned, there is no overlap of adjacent pixels; The detector is used to receive the X-ray signal scattered from the chopper device through the scanned object.

2. The X-ray based scanning imaging system according to claim 1, characterized in that: It also includes a chopper device, which is provided with a plurality of groups of light holes, each group of light holes corresponds to a column of images, and a collimator is arranged between the X-ray machine target and the chopper device, so that when the chopper device moves, at a position of the chopper device, when a linear light beam passes through the light-transmitting hole of the chopper device, it only passes through one light hole corresponding to the same row of images, and as the chopper device moves, the linear light beam passes through the light holes of the chopper device corresponding to consecutive rows of images in sequence after a certain interval.

3. The X-ray based scanning imaging system according to claim 2, characterized in that: The light holes in each group are arranged in a stepped manner, the height of the light holes projected onto the scanned object is an integral multiple of the height of a pixel, and there is at least one row of opaque areas as intervals between adjacent light holes in each group.

4. The X-ray based scanning imaging system according to claim 3, characterized in that: The chopper device is divided into at least two sub-areas, each of which contains a group of light holes. The chopper device is in a circular ring shape, and the outgoing linear light beam of the collimator is along the radius direction of the circular ring.

5. The X-ray based scanning imaging system according to claim 4, characterized in that: The chopper device is in a circular shape, and is provided with a plurality of light-transmitting positioning slits along the radial direction. The positioning slits divide the chopper device into a plurality of areas, and the light-transmitting holes in each area are arranged in a stepped manner from the outer circumference to the inner circumference.

6. The X-ray based scanning imaging system according to claim 3, characterized in that: There is at least one row of opaque areas as intervals between adjacent light-through holes of the chopping device, and the rows occupied by light-through holes of different groups are staggered.

7. The X-ray based scanning imaging system according to claim 3, characterized in that: The height of each light hole projected onto the scanned object is at least equal to twice the height of a pixel, and the rows occupied by light holes of different groups overlap.

8. The X-ray based scanning imaging system according to claim 2, characterized in that: The chopper device is in a circular shape, and the light holes in the same group are distributed on the same radius, and there is a gap between adjacent light holes in the same group; the height of the light holes projected onto the scanned object is an integer multiple of the height of a pixel point.

9. The X-ray based scanning imaging system according to claim 8, characterized in that: The chopper device is divided into at least two sub-areas along the circumference, each sub-area contains a group of light holes, and the outgoing light beam of the collimator is along the tangent direction of the inner circle of the ring.

10. The X-ray based scanning imaging system according to claim 9, characterized in that: The X-ray beam generated by the X-ray machine target is pulsed; in the time period corresponding to each column of pixels, there are beam pulses with the same interval, and the pulse interval of the beam pulses is greater than the pulse width; in the time period corresponding to each column, the beam pulses scan a column of pixels row by row.

11. The X-ray based scanning imaging system according to claim 10, characterized in that: The width and interval of the scanning beam pulses corresponding to different columns of pixels are the same, but the arrival time of the starting pulse is shifted backward by 1 / n time intervals, where n is a positive integer.

12. An X-ray based scanning imaging method according to claims 1-11, characterized in that: include: Produce an X-ray beam through an X-ray machine target; The X-ray beam is modulated into a linear beam by a collimator; The linear light beam is used to illuminate the object, and the image of the object is scanned row by row, and when the pixel points in the same row are scanned, there is no pixel overlap between each scan; The detector receives the X-ray signal scattered from the chopper through the scanned object.

13. The scanning imaging method according to claim 12, characterized in that: Also includes: Setting up the chopping device; The X-ray beam scans in the direction of the row; The X-ray beam passes through the first light hole of a group of light holes of the chopper device to scan the first group of pixel points of the first column of the image of the object; the chopper device is rotated or moved; the X-ray beam passes through the second light hole of the group of light holes to scan the second group of pixel points of the first column of the image of the object; until the X-ray beam passes through the last light hole of the first group of light holes to scan the last group of pixel points of the first column of the image of the object; thus, the scanning of the first column of the image is completed; Adjusting the relative position between the chopper device and the target point of the X-ray machine, and then performing the next row of scanning; receiving, by a detector, an X-ray signal emitted from a chopping device through a scanning sample; The relevant data are processed to complete the correction.

14. The scanning imaging method according to claim 13, characterized in that: Adjacent light holes of the chopping device are spaced apart in the direction of the column, and rows where different groups of light holes are located are staggered; in scanning of the same column of object images, a group of pixels are spaced apart between the pixels scanned each time, and after all images are scanned, the step of: performing an interpolation algorithm to calculate the image of the pixels not scanned at the interval is also included.

15. The scanning imaging method according to claim 14, characterized in that: The height of each light hole projected onto the scanned object is at least equal to twice the height of a pixel, and the heights of different groups of light holes overlap in the row direction. In the scanning of the same column of object images, when a group of pixels scanned each time includes multiple pixels, the steps also include: extracting sub-pixel information, and using projection iteration method or AI training method to achieve high-resolution reconstruction.

16. The scanning imaging method according to claim 15, characterized in that: The X-ray beam scans the object along the row direction, and the X-ray beam generated by the target point of the X-ray machine is pulsed; the image of the first column of pixel points of the object is scanned in a first time period; the image of the second column of pixel points of the object is scanned in a second time period; and the scanning of the images of all columns is completed in sequence; in the time period corresponding to each column of pixel points, there are light beam pulses with the same interval, and the pulse interval of the light beam pulses is greater than the pulse width; in the time period corresponding to each column, the light beam pulses scan a column of pixel points row by row.

17. The scanning imaging method according to claim 13, characterized in that: The width and interval of the scanning beam pulses corresponding to different columns of pixels are the same, but the arrival time of the starting pulse is shifted backward by 1 / n time intervals, where n is a positive integer.

Images