Radiation imaging device and method

Abstract

A radiation imaging device and a radiation imaging method. The radiation imaging device comprises: a radiation source (S), an N-row detector (DT) and at least one grating (G), wherein the grating (G) is arranged in an inspection channel defined by the radiation source (S) and the N-row detector (DT) and is located between the radiation source (S) and the N-row detector (DT). Each row of detectors of the N-row detector (DT) extends in the transverse direction of the inspection channel, and the N rows of detectors (DT) are arranged along the inspection channel. The grating (G) extends in a plane substantially parallel to the arrangement of the N-row detector (DT), and the at least one grating (G) has a periodic structure, the periodic structure being configured to diffuse the rays passing through the grating (G) to form an interference pattern, the direction of extension of the structural unit of the periodic structure being at a non-zero angle to the direction of extension of the inspection channel.

Description

Radiation imaging device and method

[0001] This application claims priority to Chinese patent application No. 202311771021.9 filed on December 21, 2023, the contents of which are incorporated herein by reference. Technical Field

[0002] The present disclosure relates to the field of detection technology, and in particular to a radiation imaging device. Background Art

[0003] Since the introduction of grating imaging technology, the most commonly used scanning method has been phase-stepping scanning. This requires the object and the imaging system to remain stationary, while one of the gratings is moved to generate a phase-stepping curve, thereby extracting three types of image information: absorption, phase, and small-angle scattering. This traditional scanning method has limited the practical application of grating imaging technology, and there is an urgent need to improve its scanning efficiency to meet the needs of real-world production and life.

[0004] The traditional phase stepping scanning method is very time-consuming and not suitable for the needs of practical application scenarios. It is hoped to provide a grating imaging device and method that improves efficiency and can provide more information. Summary of the Invention

[0005] According to one aspect of the present disclosure, there is provided a radiation imaging device, comprising:

[0006] a radiation source configured to emit a radiation beam;

[0007] N rows of detectors configured to receive the radiation beam from the radiation source, the radiation source and the N rows of detectors defining an inspection channel, wherein N is an integer greater than 1; and

[0008] at least one grating disposed in the inspection channel between the radiation source and the detector;

[0009] Each row of the N rows of detectors extends transversely to the inspection channel, the N rows of detectors are arranged along the extension direction of the inspection channel, the at least one grating extends in a plane substantially parallel to the arrangement of the N rows of detectors, and the at least one grating has a periodic structure, the periodic structure is configured to cause rays passing through the periodic structure of the grating to diffract to form an interference pattern, and the extension direction of the structural units of the periodic structure forms a non-zero angle with the extension direction of the inspection channel.

[0010] In one embodiment, the radiation imaging device is configured to emit N radiation beams through the radiation source while the N rows of detectors detect radiation signals passing through the object when the object moves on the inspection channel, and expose the object N times, and the number of exposures is the same as the number of rows of detectors.

[0011] In one embodiment, the exposure is an interval exposure, and in the interval between the start times of two adjacent exposures, the movement distance of the object is equal to the spacing between the corresponding front edges of adjacent rows of detectors, and the exposure includes multiple interval exposures with the same exposure time.

[0012] In one embodiment, the radiation imaging device is configured to apply a first extraction algorithm to generate at least one of an absorption image, a phase image, and a small-angle scattering image related to at least a partial area of ​​the object under test based on the exposure data of the first row of detectors of the N rows of detectors during the first exposure, the exposure data of the i-th row of detectors of the N rows of detectors during the i-th exposure, and other completed multiple exposure data as exposure data related to at least a partial area of ​​the object under test, where i is an integer and 1<i≤N.

[0013] In one embodiment, the radiation imaging device is configured to, when the object to be inspected is placed stationary on the inspection channel, emit the radiation beam through the radiation source to illuminate the object to be inspected, and detect the radiation signal transmitted through the object through the N rows of detectors to expose the object to be inspected.

[0014] In one embodiment, the radiation imaging device is configured to apply a second extraction algorithm based on the exposure data of each row of detectors in the N rows of detectors to at least a partial area of ​​the object to be inspected, so as to extract and combine the exposure data of M adjacent rows of detectors in the N rows of detectors into a group of exposure data, thereby obtaining N-M+1 groups of exposure data, and generate at least one of an absorption image, a phase image, and a small-angle scattering image related to at least a partial area of ​​the object to be inspected based on the N-M+1 groups of exposure data, where M is an integer and 1≤M≤N.

[0015] In one embodiment, the at least one grating comprises a first grating arranged between the object to be inspected and the N rows of detectors.

[0016] In one embodiment, the at least one grating comprises a second grating arranged between the object to be detected and the radiation source.

[0017] In one embodiment, the at least one grating further comprises a third grating arranged between the object to be inspected and the N rows of detectors, wherein the distance between the third grating and the first grating and the N rows of detectors is different.

[0018] In one embodiment, the N rows of detectors are spaced apart at equal predetermined intervals along the inspection channel, or are arranged closely adjacent to each other.

[0019] In one embodiment, the radiation source is a multi-point distributed radiation source, which is configured such that multiple point sources emit radiation beams from multiple angles to illuminate the object under inspection.

[0020] In one embodiment, each point source of the multi-point distributed radiation source emits a radiation beam respectively to expose the object under inspection multiple times.

[0021] According to another aspect of the present disclosure, there is provided a radiation imaging method, comprising:

[0022] irradiating the object with a radiation source; and

[0023] receiving a radiation beam from the radiation source using N rows of detectors, wherein the radiation source and the N rows of detectors define an examination channel, wherein N is an integer greater than 1;

[0024] Each row of the N rows of detectors extends transversely to the inspection channel, the N rows of detectors are arranged along the extension direction of the inspection channel, the at least one grating extends in a plane substantially parallel to the arrangement of the N rows of detectors, and the at least one grating has a periodic structure, the periodic structure is configured to cause rays passing through the periodic structure of the grating to diffract to form an interference pattern, and the extension direction of the structural units of the periodic structure forms a non-zero angle with the extension direction of the inspection channel.

[0025] In one embodiment, the object to be inspected moves along the inspection channel, or the object to be inspected is stationary in the inspection channel.

[0026] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present disclosure, nor are they intended to limit the scope of the present disclosure. Other features of the present disclosure will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings are used to better understand the present solution and do not constitute a limitation of the present disclosure, wherein:

[0028] FIG1 shows an example of the arrangement of a grating in a radiation imaging device.

[0029] FIG2 shows an example of a radiometric imaging process in which the grating is moved in a stepwise manner.

[0030] FIG3 shows a schematic diagram of radiation imaging according to an embodiment of the present disclosure, wherein the object under inspection moves in an inspection channel.

[0031] FIG4 illustrates a radiometric imaging process including information extraction from multiple exposures according to an embodiment of the present disclosure.

[0032] FIG5 shows a schematic diagram of radiation imaging according to an embodiment of the present disclosure, wherein the object to be inspected is placed statically in an inspection channel.

[0033] FIG6 illustrates a radiation imaging process including single exposure information extraction according to an embodiment of the present disclosure.

[0034] Figure 7 shows the two-dimensional images of absorption T(a), phase Φ(b) and small-angle scattering D(c) obtained by the device according to the present invention, and the corresponding XY plane slice images of the three-dimensional images of the linear attenuation coefficient μ(d), refractive index decrement δ(e), and linear diffusion coefficient ζ(f) reconstructed using the FBP algorithm after collecting 360 projections during one rotation. DETAILED DESCRIPTION

[0035] To more clearly illustrate the objectives, technical solutions, and advantages of the present disclosure, embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the following description of the embodiments is intended to explain and illustrate the overall concept of the present disclosure and should not be construed as limiting the present disclosure. In the specification and drawings, the same or similar reference numerals refer to the same or similar parts or components. For the sake of clarity, the drawings are not necessarily drawn to scale, and some well-known parts and structures may be omitted in the drawings.

[0036] Unless otherwise defined, technical or scientific terms used in this disclosure should have the ordinary meaning understood by a person of ordinary skill in the art to which this disclosure belongs. The terms "first," "second," and similar terms used in this disclosure do not denote any order, quantity, or importance, but are simply used to distinguish different components. The terms "a" or "an" do not exclude a plurality. Terms such as "include" or "comprise" mean that the element or object preceding the term includes the elements or objects listed after the term and their equivalents, but do not exclude other elements or objects. Terms such as "connected" or "connected" are not limited to physical or mechanical connections but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," "right," "top," or "bottom" are used only to indicate relative positional relationships; if the absolute position of the described objects changes, the relative positional relationship may also change accordingly. When an element such as a layer, film, region, or substrate is referred to as being "on" or "under" another element, the element may be "directly" "on" or "under" the other element, or intervening elements may be present.

[0037] This disclosure describes a grating rapid imaging system that utilizes N rows of detectors and a grating placed upstream (in front of) the detectors to extract three types of information: absorption, phase, and small-angle scattering from projection data. Because the grating modulates the rays, for multiple rows of detectors, different units (such as pixels) in different detectors receive different modulated rays. For example, the modulated rays exhibit streaky characteristics. The modulated rays are "carrier waves," and their shape results in a period that differs from the period of the N rows of detectors. Different structures are calculated using an information extraction algorithm, and the computational solution process can be understood as a process similar to demodulation. The following first explains the application principle of gratings in ray transmission imaging.

[0038] Figures 1(a), (b), (c) and (d) show various grating imaging arrangements, where G1, G2 and G3 represent three gratings, which are arranged between the source S and the object W, or between the object W and the detector DT, respectively.

[0039] In grating imaging technology, the wave and particle properties of X-rays can be simultaneously utilized to obtain three characteristic information: absorption, phase, and small-angle scattering. The absorption and phase information correspond to the imaginary part β and real part δ of the complex refractive index n, respectively: n = 1-δ + iβ (1)

[0040] The linear attenuation coefficient μ is linearly related to the imaginary part β (λ is the wavelength of the X-ray):

[0041] The three multi-characteristic information of absorption T, phase Φ and small-angle scattering D can be regarded as the integral of linear attenuation coefficient μ, refractive index decrement δ, and linear diffusion coefficient ζ respectively (where L is the propagation path of X-rays, c Φ and c D are all constant values ​​related to the imaging system):

[0042] Considering that X-rays usually have an energy spectrum distribution, assuming that the normalized energy spectrum distribution is S(E), formula (3) can be written as:

[0043] In Figure 1(a), grating G1 forms a self-imaging fringe pattern on its trailing optical path. When X-rays interact with matter, these self-imaging fringes may undergo local distortion. This distortion occurs on the micron or even submicron scale, a level beyond the resolution of conventional detectors. Therefore, grating G2 amplifies this signal and, by observing variations in the detector signal, extracts three multi-characteristic images: absorption, phase, and small-angle scattering. When the X-ray source's focal point is sufficiently small (e.g., synchrotron radiation or microfocus optical systems), only gratings G1 and G2 are required, as shown in Figures 1(a) and 1(c).

[0044] When the focal spot size of the X-ray source is large (such as a conventional X-ray machine), the blurring effect it brings will lead to poor imaging quality. Therefore, a grating G0 is added after the X-ray source. Due to the grating G0, the radiation beam emitted by the X-ray source is converted into a series of partially coherent micron-level linear radiation beams, as shown in Figure 1(b) and (d).

[0045] The object W can be placed between the grating G0 and the grating G1 ( FIG. 1( b ) ), or between the grating G1 and the grating G2 ( FIG. 1( c ) and ( d ) ).

[0046] When the object W is placed between gratings G0 and G1, as shown in Figure 1(b), the phase and small-angle scattering signals obtained in this configuration are stronger, and the imaging contrast and sensitivity are higher. However, there are also disadvantages, namely, the large area and high cost of grating G1, and the X-rays after passing through the object W need to be blocked by gratings G1 and G2 before they can be received by the detector, resulting in low X-ray utilization.

[0047] When the object W is placed between gratings G1 and G2, as shown in Figures 1(c) and (d), in this configuration, grating G1 is close to the light source, has a small area and low cost, and the X-rays passing through the object W are only blocked by grating G2, which increases the X-ray utilization rate. However, it also has disadvantages. The obtained phase and small-angle scattering signals are weakened. However, for some strongly scattering materials, this is not likely to cause detector signal saturation.

[0048] The absorption image (T above) reflects the material's attenuation characteristics for X-rays and corresponds to the imaginary part of the material's complex refractive index, β (complex refractive index n = 1-δ + iβ). The phase image reflects the material's refractive effect on X-rays and corresponds to the real part of the material's complex refractive index, δ. This has the beneficial effect of providing higher contrast for weakly absorbing materials than the absorption image, with δ being 2 to 3 orders of magnitude higher than β. Therefore, weakly absorbing materials can be more clearly visualized using the phase image. The small-angle scattering image reflects the material's mesoscopic structural information and is highly sensitive to micron or submicron differences in porosity and fibrous structures, potentially overcoming the limitations of absorption imaging resolution. Phase and small-angle scattering images complement the absorption image, effectively improving the overall imaging quality and resolution of the object under test, W, and enhancing the adaptability and accuracy of the inspection process for different materials.

[0049] Figure 7 shows two-dimensional images of absorption T (a), phase Φ (b), and small-angle scattering D (c), along with corresponding XY plane slice images of the linear attenuation coefficient μ (d), refractive index decrement δ (e), and linear diffusion coefficient ζ (f), reconstructed using the FBP algorithm after collecting 360 projections during one rotation (corresponding to formula (3) in the handout). The absorption image (corresponding to the linear attenuation coefficient μ) reflects the attenuation characteristics of the material; the phase image (corresponding to the refractive index decrement δ in the complex refractive index) with higher contrast for weakly absorbing materials reflects the texture information of the internal and external structures of the object under test W; and the small-angle scattering image (corresponding to the linear diffusion coefficient ζ) reflects the mesoscopic structural information of the material, reflecting microstructures such as porosity and multi-fibers at the micron / submicron scale.

[0050] In a traditional grating imaging system, the object W needs to be stopped, and then one of the three gratings needs to be moved to obtain the displacement curve corresponding to each pixel point, thereby extracting the absorption, phase and small-angle scattering information of each pixel point.

[0051] For example, as shown in Figure 2(a), the object W is stationary, and one of the gratings (such as grating G2) is moved. Multiple measurement results can be obtained on each detector pixel, corresponding to the displacement curve in Figure 2b. The result obtained when scanning without an object is called the "background displacement curve", and the result obtained when scanning with an object is called the "object displacement curve". These two displacement curves are used to extract three types of multi-characteristic image information.

[0052] The disadvantage of this method is that it requires moving the grating and the scanning takes too long, making it unsuitable for practical application requirements.

[0053] As shown in FIG3 , according to one embodiment of the present disclosure, a grating imaging device includes a radiation source S, multiple rows of detectors DT, and at least one grating G. While FIG3 illustrates the detectors DT and grating G together as DT-G, they are actually separate components. FIG3 merely schematically illustrates the arrangement of the multiple rows of detectors DT. Furthermore, in FIG3 , the Z direction represents the direction in which the multiple rows of detectors DT are arranged. For example, five rows of detectors DT are arranged along the Z direction. The detectors shown in FIG3 can be considered to be the ends of each row of detectors DT. The grating G is arranged near the detectors DT, for example, adjacent to the detectors DT and extending along the Z direction. In one embodiment, the grating G is arranged parallel to the multiple rows of detectors DT.

[0054] For convenience of presentation, this disclosure uses the term "N rows" to represent multiple rows, where N is an integer greater than 1, such as 2, 3, 4, 5, 6, 7, or a larger integer. FIG3 illustrates an example where N is 5. The N rows of detectors can be determined by a suitable integer based on needs and cost considerations. Furthermore, i is used in the description as an integer between 1 and N to represent a particular row of detectors within the N rows of detectors. Those skilled in the art are familiar with this common mathematical usage. It should be understood that the use of "N rows" to represent multiple rows is merely for convenience and has no other specific meaning. A radiation source S can emit a radiation beam, such as an X-ray source. Here, the radiation source S can include a collimator that provides a desired shape or form of the radiation beam. The N rows of detectors are configured to receive the radiation beam from the radiation source S and sense properties of the radiation beam, such as intensity, using radiation-sensitive elements. The radiation source S and the detectors define an inspection channel, along which an object W can be irradiated by the radiation source S. The radiation beam transmitted through the object W is detected by the N rows of detectors, thereby determining various properties and contours of the object W.

[0055] Each row of N rows of detectors extends in the transverse direction of the inspection channel (perpendicular to the YZ plane), and the N rows of detectors are arranged along the extension direction (Z direction) of the inspection channel. For example, as shown in FIG3 , the arrow in the figure indicates the direction in which the inspection channel extends, which is also the direction in which the object W moves in the inspection channel, that is, the Z direction. The N rows of detectors are arranged along the direction of the arrow (Z direction), and FIG3 shows 5 rows of detectors arranged along the inspection channel. Each row of detectors DT extends in the transverse direction of the inspection channel. In the cross-sectional schematic diagram shown in FIG3 , the end face of each row of detectors can be seen, and each row of detectors DT extends from the paper surface to the inside of the paper surface. FIG3 shows that the 5 rows of detectors are closely packed, that is, adjacent detectors are close together; however, in other embodiments, adjacent rows of detectors can be spaced apart, or there are gaps between the detectors.

[0056] In an embodiment of the present disclosure, a grating imaging device includes at least one grating, which is arranged in the inspection channel between the radiation source S and the detector. At least one grating has a periodic structure, and the periodic structure is configured to diffract rays passing through the periodic structure of the grating to form an interference pattern. The periodic structure can be, for example, a periodic slit, or it can be said that the structural unit of the periodic structure can be a slit, and the ray or light will undergo diffraction when passing through the slit, and the ray or light is thereby changed. To a certain extent, it can be considered that the ray is modulated by the periodic structure. Here, the periodic structure can be, for example, a slit. Taking the periodic structure as an example, the periodic direction of the periodic structure can be the arrangement direction of multiple slits. For example, in an embodiment where the periodic structure is a slit, the structural unit of the periodic structure is a single slit, and when its extension direction forms an extremely small angle with the inspection channel (extension direction) (for example, relative to a situation where it is parallel to the inspection channel), for example, 10-4 degrees, the interference fringes or moiré fringes generated by the periodic structure composed of the arrangement of multiple slits will undergo a significant change, and thus, as long as the extension direction of a single slit forms an extremely small angle with the inspection channel, the requirements of the present disclosure can be met. In a specific embodiment, for example, the extension direction of a single slit can be transverse to the extension direction (Z direction) of the inspection channel (i.e., perpendicular to the inspection channel), in which case the arrangement direction of the slits (i.e., the periodic direction of the periodic structure) is parallel to the extension direction of the inspection channel, or in other words, the arrangement direction of the slits is along the Z direction. In other embodiments, the periodic structure can be other structures instead of slits, for example, a material that can produce a stripe pattern. In FIG3 , the detector and the grating are shown as a whole to facilitate the arrangement of the detector and the movement of the object W. In fact, the grating can be located upstream of the detector facing the radiation beam, such as close to the detector, or it can be located at a certain distance from the detector, such as between the object W and the source S.

[0057] In the present disclosure, at least one grating may be a grating, for example, arranged adjacent to a detector, i.e., radiation passes through the object W and then passes through the grating and is detected by the detector; in another embodiment, the grating may be located between the detector and the object W and at a certain distance from the detector.

[0058] In one embodiment, a grating may be provided close to the radiation source S. In one embodiment, the at least one grating may be two gratings, and the two gratings are arranged between the detector and the object W; in another embodiment, the two gratings are arranged between the detector and the object W and between the object W and the radiation source S, respectively.

[0059] In one embodiment, the at least one grating may be three gratings, two of which are arranged between the detector and the object W, and one of which is arranged between the object W and the radiation source S. In another embodiment, the at least one grating may be three gratings, one of which is arranged between the detector and the object W, and two of which are arranged between the object W and the radiation source S. Figure 1 shows schematic diagrams of various arrangements of gratings between the radiation source S and the detector. In the present invention, the grating may have a grating surface.

[0060] In one embodiment, a first grating is arranged between the object under test and the N rows of detectors. In one embodiment, a second grating is arranged between the object under test and the radiation source. In one embodiment, a third grating is arranged between the object under test and the N rows of detectors, wherein the third grating is at a different distance from the first grating and the N rows of detectors. Regarding the gratings above, in order to avoid complicating the drawings, the specific form of the gratings is not shown in the drawings. However, the embodiments of the present disclosure can be implemented by referring to the arrangement of the gratings in FIG. 1 .

[0061] In one embodiment of the present disclosure, during the detection process of the object W, the object W can move. The following describes the exposure and imaging methods of the moving process. Assuming that the object W moves at a uniform speed v and the time interval between two exposures is Δt, the displacement of the object W during the two exposure intervals is l = vΔt; assuming that the distance between adjacent rows of detectors is Δ det , according to the scanning mode of the grating imaging device in this embodiment, the following relationship is satisfied: Δ det =v·Δt (5)

[0062] The above formula means that during the interval between the start times of two exposures, the corresponding portion or unit of the object W moves by the distance between adjacent rows of detectors (i.e., the distance between the leading edges of two adjacent rows of detectors, or the distance between their centers or trailing edges). This ensures that the first row of detectors in the first exposure, the second row of detectors in the second exposure, the third row of detectors in the third exposure, and so on (and so on) detect the same portion or unit of the scanned object. It should be noted that exposure refers to the process from turning on the detectors to detecting radiation signals to turning off the detectors to terminate detection. During this process, the radiation source S may continuously illuminate the object W; it may also be pulsed, with the detection time being consistent or inconsistent, but the radiation source S does not continuously illuminate the object W. It should be noted that the above relationship between movement and exposure can actually be for a portion or unit of the object, and does not refer to the number of times the entire object is exposed. For example, when the object is large, the number of exposures will obviously be greater than five when the object passes through five rows of detectors, such as shown in FIG3 .

[0063] In one embodiment, in an embodiment of the interval exposure, the time period of each exposure cycle includes an exposure time and a remaining time, and the time interval between the start times of two exposures completes one exposure, or the time interval between the start times of two exposures is one exposure cycle. In each exposure cycle, the object W can be irradiated with a pulsed radiation beam during the exposure time, and during the remaining time (before the next exposure starts), the object W continues to move but is not irradiated with radiation.

[0064] For any detector pixel, its signal intensity can be expressed as a cosine function:

[0065] In the above formula, i represents the i-th pixel in the j-th row of detector pixels, and k represents the exposure number. For the same pixel, It is only related to the pixel and has nothing to do with the object being tested W, and is called the "detector constant". k , D k ,φ k It is only related to the object W and has nothing to do with the pixel itself. It is called "multi-characteristic information" and is related to absorption, small-angle scattering and phase information respectively. When the channel is not placed with the object W, T k =1,D k =1,φ k =0, that is:

[0066] In the embodiments of the present disclosure, the object W can move. During the movement of the object W, the radiation source S emits a radiation beam to expose the object W, wherein the movement speed of the object W is coordinated with the spacing between the detectors so that the distance moved by the object W in the time interval between the start time of the first exposure and the start time of the second exposure is equal to the spacing between the leading edges (or trailing edges) of adjacent detectors.

[0067] When the object W moves as described above, the first extraction algorithm is applied to perform data processing. As shown in FIG4 , the first exposure obtains the first exposure data of the first row of detectors, the second exposure obtains the second exposure data of the second row of detectors, and so on. The Nth exposure obtains the Nth exposure data of the Nth row of detectors. Using the first to Nth exposure data of multiple exposures, the above equation (3) is used respectively. Each exposure data can be substituted into an equation. At least three exposure data are required to construct a system of equations. The system of equations is solved using an optimization method to obtain the results of absorption T, phase Φ, and small-angle scattering D. Those skilled in the art can also use other known solution methods to solve the system of equations, such as Fourier transform, etc.

[0068] In an embodiment of the present disclosure, an object W is placed stationary in an inspection channel. As shown in FIG5 , the object W is exposed once. Exposure data from each corresponding row of detectors is collected using N rows of detectors. A second extraction algorithm is then applied to the data for processing. Specifically, as shown in FIG6 , based on the first set of exposure data from the first row of detectors, the second set of exposure data from the second row of detectors, and the Nth set of exposure data from the Nth row of detectors obtained from the same exposure, it is assumed that the unknown variables in adjacent rows can be considered identical ("spatial downsampling"). Therefore, the corresponding sets of exposure data from adjacent rows of detectors, such as three sets of exposure data from three adjacent rows of detectors, can be used as a combination to solve the system of equations. In other embodiments, exposure data from M adjacent rows of detectors within the N rows of detectors can also be extracted and combined into a set of exposure data, resulting in N−M+1 sets of exposure data. Based on the N−M+1 sets of exposure data, at least one of an absorption image, a phase image, and a small-angle scattering image is generated for at least a portion of the region of the object W.

[0069] In one embodiment of the present disclosure, two rows of detectors are provided. Generally speaking, a grating imaging system can simultaneously obtain three types of information: absorption T, phase Φ, and small-angle scattering D. However, in the imaging process under certain imaging conditions, the spatial distribution of the phase information Φ or small-angle scattering information D of the object under test changes relatively slowly or the signal is relatively weak, and thus can be regarded as constants. During the information extraction process, only two unknown quantities need to be considered. For example, in one embodiment, if the spatial distribution of phase information Φ changes slowly or the signal is relatively weak, only the absorption information T and small-angle scattering information D are considered; in another embodiment, if the spatial distribution of small-angle scattering information D changes slowly or the signal is relatively weak, only the absorption information T and phase information Φ are considered. In these embodiments, only two rows of detectors are required (for N=2), and the data acquisition process is the same as for the case where N≥3, except that the number of detector rows is reduced.

[0070] In the present disclosure, a radiation imaging method is provided, comprising: irradiating an object W using a radiation source S; and receiving a radiation beam from the radiation source S using N rows of detectors, wherein the radiation source S and the N rows of detectors define an inspection channel, where N is an integer greater than 1. In this embodiment, each row of the N rows of detectors extends transversely of the inspection channel, the N rows of detectors are arranged along an extension direction of the inspection channel, the at least one grating extends in a plane substantially parallel to the arrangement of the N rows of detectors, and the at least one grating has a periodic structure, the periodic structure is configured to cause rays passing through the periodic structure of the grating to diffract to form an interference pattern, and the extension direction of the structural units of the periodic structure forms a non-zero angle with the extension direction of the inspection channel.

[0071] In one embodiment, the object W moves along the inspection channel, or the object W is stationary in the inspection channel.

[0072] When the object W moves within the inspection channel, multiple exposures are performed, and a first extraction algorithm is applied to generate at least one of an absorption image, a phase image, and a small-angle scattering image for at least a portion of the object W. When the object W is stationary within the inspection channel, a second extraction algorithm is applied to generate at least one of an absorption image, a phase image, and a small-angle scattering image for at least a portion of the object W based on N-M+1 sets of exposure data. For details, please refer to the aforementioned description.

[0073] It should be understood that according to embodiments of the present disclosure, the object W can be moved and then placed stationary in the inspection channel. In this case, a first extraction algorithm can be applied to the exposure data collected while the object W was moving to generate at least one of an absorption image, a phase image, and a small-angle scattering image associated with at least a portion of the object W. A second extraction algorithm can be applied to the exposure data collected while the object W was stationary in the inspection channel to generate at least one of an absorption image, a phase image, and a small-angle scattering image associated with at least a portion of the object W. In this embodiment, the two calculated absorption images, phase images, and small-angle scattering images can be compared and mutually verified to improve inspection accuracy.

[0074] It should be understood that the various forms of the processes shown above can be used to reorder, add, or delete steps. For example, the steps described in this disclosure can be performed in parallel, sequentially, or in a different order, as long as the desired results of the technical solutions disclosed in this disclosure can be achieved. This is not limited herein.

[0075] In the technical solutions disclosed herein, the collection, storage, use, processing, transmission, provision and disclosure of user personal information involved comply with the provisions of relevant laws and regulations and do not violate public order and good morals.

[0076] The above specific embodiments do not constitute a limitation on the scope of protection of this disclosure. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this disclosure shall be included within the scope of protection of this disclosure.

Claims

1. A radiation imaging device, comprising: a radiation source configured to emit a radiation beam; N rows of detectors configured to receive a radiation beam from the radiation source, the radiation source and the N rows of detectors defining an inspection channel, wherein N is an integer greater than 1; as well as at least one grating disposed in the inspection channel between the radiation source and the detector; Each row of the N rows of detectors extends transversely of the inspection channel, the N rows of detectors are arranged along the extension direction of the inspection channel, the at least one grating extends in a plane substantially parallel to the arrangement of the N rows of detectors, and the at least one grating has a periodic structure, the periodic structure is configured to cause rays passing through the periodic structure of the grating to diffract to form an interference pattern, and the extension direction of the structural units of the periodic structure forms a non-zero angle with the extension direction of the inspection channel.

2. The radiation imaging device according to claim 1 is configured such that when the object to be inspected moves on the inspection channel, the radiation source emits N radiation beams and the N rows of detectors detect the radiation signals passing through the part of the object to be inspected, and the part of the object to be inspected is exposed N times, and the number of exposures is the same as the number of rows of detectors.

3. A radiation imaging device according to claim 2, wherein the exposure is an interval exposure, and in the interval between the start times of two adjacent exposures, the movement distance of the part of the object to be inspected is equal to the spacing between the corresponding front edges of adjacent rows of detectors, and the exposure includes multiple interval exposures with the same exposure time.

4. The radiation imaging device according to claim 2, wherein the radiation imaging device is configured to, for the portion of the object to be inspected, apply a first extraction algorithm to generate at least one of an absorption image, a phase image, and a small-angle scattering image related to at least a partial area of ​​the object to be inspected based on the exposure data of the first row of detectors of the N rows of detectors during the first exposure, the exposure data of the i-th row of detectors of the N rows of detectors during the i-th exposure, and other completed multiple exposure data as the exposure data related to the partial area of ​​the object to be inspected, wherein i is an integer and 1<i≤N.

5. The radiation imaging device according to claim 1 is configured such that when the object to be inspected is placed still on the inspection channel, the radiation source emits the radiation beam to irradiate the object to be inspected, and the N rows of detectors detect the radiation signal passing through the object to be inspected, thereby exposing the object to be inspected.

6. The radiation imaging device according to claim 5, wherein the radiation imaging device is configured to apply a second extraction algorithm based on the exposure data of each row of the N rows of detectors to at least a partial area of ​​the object to be inspected, so as to extract and combine the exposure data of M adjacent rows of detectors in the N rows of detectors into a group of exposure data, obtain N-M+1 groups of exposure data, and generate at least one of an absorption image, a phase image and a small-angle scattering image related to at least a partial area of ​​the object to be inspected based on the N-M+1 groups of exposure data, wherein M is an integer and 1≤M≤N. 7 . The radiation imaging device according to claim 1 , wherein the at least one grating comprises a first grating arranged between the object to be inspected and the N rows of detectors. 8 . The radiation imaging device according to claim 7 , wherein the at least one grating comprises a second grating arranged between the object to be inspected and the radiation source.

9. The radiation imaging device according to claim 8, wherein the at least one grating further comprises a third grating arranged between the object to be inspected and the N rows of detectors, wherein the distance between the third grating and the first grating and the N rows of detectors is different.

10. The radiation imaging device according to claim 1, wherein the N rows of detectors are spaced apart at equal predetermined intervals along the inspection channel, or are arranged closely to each other.

11. The radiation imaging device according to claim 4, wherein the radiation source is a multi-point distributed radiation source, configured such that a plurality of point sources emit radiation beams from a plurality of angles to irradiate the object under inspection.

12. The radiation imaging device according to claim 11, wherein each point source of the multi-point distributed radiation source emits a radiation beam respectively to expose the object to be inspected multiple times.

13. A radiation imaging method, comprising: Using a radiation source to irradiate the object under test; and receiving a radiation beam from the radiation source using N rows of detectors, wherein the radiation source and the N rows of detectors define an inspection channel, wherein N is an integer greater than 1; Each row of the N rows of detectors extends transversely of the inspection channel, the N rows of detectors are arranged along the extension direction of the inspection channel, the at least one grating extends in a plane substantially parallel to the arrangement of the N rows of detectors, and the at least one grating has a periodic structure, the periodic structure is configured to cause rays passing through the periodic structure of the grating to diffract to form an interference pattern, and the extension direction of the structural units of the periodic structure forms a non-zero angle with the extension direction of the inspection channel. 14 . The radiation imaging method according to claim 13 , wherein the object under inspection moves along the inspection channel, or the object under inspection is stationary in the inspection channel.

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