Radiation imaging apparatus and method

Abstract

The invention provides a radiation imaging apparatus. The apparatus includes a radiation source, N rows of detectors, and at least one grating disposed between an inspection channel defined by the radiation source and the detectors between the radiation source and the detectors. Each row of detectors in the N rows of detectors extends along the transverse direction of the inspection channel, and the N rows of detectors are arranged along the inspection channel. The gratings extend in a plane substantially parallel to the arrangement of the N rows of detectors, and the at least one grating has a periodic structure configured to diffract rays passing through the grating to form an interference pattern, and a non-zero angle is formed between the extension direction of the structural units of the periodic structure and the extension direction of the inspection channel.

Description

Technical Field

[0001] The present invention relates to the field of detection technologies. Specifically, it relates to a radiation imaging device. Background Art

[0002] Since the grating imaging technology was proposed, the most commonly used scanning method is phase-stepping scanning. That is, each time, the object to be inspected and the imaging system need to remain stationary, and then one of the gratings is moved to obtain a phase-stepping curve, so as to extract three kinds of image information: absorption, phase, and small-angle scattering. The above traditional scanning method limits the practical application of the grating imaging technology. It is necessary to urgently improve its scanning efficiency to meet the needs of actual production and life.

[0003] The traditional phase-stepping scanning method is very time-consuming and does not meet the requirements of actual application scenarios. It is hoped to provide a grating imaging device and method with improved efficiency and capable of providing more information. Summary of the Invention

[0004] According to one aspect of the present invention, there is provided a radiation imaging device, comprising:

[0005] A radiation source configured to emit a radiation beam;

[0006] 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, where N is an integer greater than 1; and

[0007] At least one grating arranged between the radiation source and the detectors in the inspection channel;

[0008] Wherein each row of the N rows of detectors extends transversely along the inspection channel, the N rows of detectors are arranged along the extending direction of the inspection channel, the at least one grating extends in a plane substantially parallel to the plane in which the N rows of detectors are arranged, and the at least one grating has a periodic structure, the periodic structure is configured to diffract the rays passing through the periodic structure of the grating to form an interference pattern, and the extending direction of the structural unit of the periodic structure forms a non-zero angle with the extending direction of the inspection channel.

[0009] In one embodiment, the radiation imaging device is configured to, when the object to be inspected moves on the inspection channel, emit N radiation beams through the radiation source while the N rows of detectors detect the radiation signals transmitted through the object to be inspected, and perform N exposures on the object to be inspected, the number of exposures being the same as the number of rows of detectors.

[0010] In one embodiment, the exposure is a stepped exposure, and during the interval between the start times of two adjacent exposures, the movement distance of the object under inspection is equal to the pitch between the corresponding front edges of adjacent rows of detectors. The exposure includes multiple stepped exposures with the same exposure time.

[0011] In one embodiment, the radiation imaging device is configured to, for at least a partial region of the object under inspection, based on the exposure data of the first row of the N rows of detectors during the first exposure, the exposure data of the i-th row of the N rows of detectors during the i-th exposure, and the exposure data of other multiple completed exposures, as the exposure data related to at least a partial region of the object under inspection, 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 region of the object under inspection, where i is an integer and 1 < i ≤ N.

[0012] In one embodiment, when the object under inspection is stationary on the inspection channel, the radiation imaging device emits the radiation beam through the radiation source to irradiate the object under inspection, and the N rows of detectors detect the radiation signal passing through the object under inspection to expose the object under inspection.

[0013] In one embodiment, the radiation imaging device is configured to, for at least a partial region of the object under inspection, apply a second extraction algorithm based on the exposure data of each row of the N rows of detectors, so as to extract and combine the exposure data of adjacent M rows of detectors among the N rows of detectors into a set of exposure data, obtain N - M + 1 sets 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 region of the object under inspection based on the N - M + 1 sets of exposure data, where M is an integer and 1 ≤ M ≤ N.

[0014] In one embodiment, the at least one grating includes a first grating disposed between the object under inspection and the N rows of detectors.

[0015] In one embodiment, the at least one grating includes a second grating disposed between the object under inspection and the radiation source.

[0016] In one embodiment, the at least one grating further includes a third grating disposed between the object under inspection and the N rows of detectors, where the distance between the third grating and the first grating and the N rows of detectors is different.

[0017] In one embodiment, the N rows of detectors are spaced apart at equal predetermined pitches along the inspection channel or are arranged adjacent to each other.

[0018] In one embodiment, the radiation source is a multi-point distributed radiation source configured such that multiple point sources emit radiation beams from multiple angles to irradiate the object under inspection.

[0019] In one embodiment, each point source of the multi-point distributed radiation source emits a radiation beam respectively, and the object to be inspected is exposed multiple times.

[0020] According to another aspect of the present invention, there is provided a radiation imaging method, comprising:

[0021] irradiating an object to be inspected with a radiation source; and

[0022] using N rows of detectors to receive radiation beams from the radiation source, wherein the radiation source and the N rows of detectors define an inspection channel, and N is an integer greater than 1;

[0023] wherein each row of the N rows of detectors extends transversely to the inspection channel, the N rows of detectors are arranged along the extending direction of the inspection channel, at least one grating extends in a plane substantially parallel to the plane in which the N rows of detectors are arranged, and the at least one grating has a periodic structure, the periodic structure is configured to diffract rays passing through the periodic structure of the grating to form an interference pattern, and the extending direction of the structural unit of the periodic structure forms a non-zero angle with the extending direction of the inspection channel.

[0024] In one embodiment, the object to be inspected moves along the inspection channel in the inspection channel, or the object to be inspected is stationary in the inspection channel.

[0025] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the present invention, nor is it used to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. Description of the Drawings

[0026] The drawings are used to better understand the present solution and do not constitute a limitation to the present invention, wherein:

[0027] Figure 1 shows an example of the arrangement of a grating in a radiation imaging device.

[0028] Figure 2 shows an example of a radiation imaging process, in which the grating moves in a step-by-step manner.

[0029] Figure 3 shows a schematic diagram of radiation imaging according to an embodiment of the present invention, wherein the object to be inspected moves in the inspection channel.

[0030] Figure 4 shows a radiation imaging process according to an embodiment of the present invention, which includes information extraction of multiple exposures.

[0031] Figure 5Shows a schematic diagram of radiation imaging according to an embodiment of the present invention, where the object to be examined is statically placed in the inspection channel.

[0032] Figure 6 Shows the radiation imaging process according to an embodiment of the present invention, which includes information extraction of a single exposure.

[0033] 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 XY-plane slice images of the three-dimensional images of linear attenuation coefficient μ(d), refractive index decrement δ(e), and linear diffusion coefficient ζ(f) reconstructed by using the FBP algorithm after collecting 360 projections in one rotation. Detailed implementation manners

[0034] To more clearly elaborate the purpose, technical solution, and advantages of the present invention, the embodiments of the present invention 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 general concept of the present invention, and should not be construed as a limitation to the present invention. In the specification and drawings, the same or similar reference numerals refer to the same or similar components or elements. For clarity, the drawings are not necessarily drawn to scale, and some well-known components and structures may be omitted in the drawings.

[0035] Unless otherwise defined, the technical terms or scientific terms used in the present invention should have the ordinary meanings understood by those of ordinary skill in the art to which the present invention pertains. The terms "first", "second", and the like used in the present invention do not denote any order, quantity, or importance, but are only used to distinguish different components. The word "a" or "an" does not exclude a plurality. The terms such as "comprising" or "including" mean that the elements or objects appearing before this word cover the elements or objects listed after this word and their equivalents, without excluding other elements or objects. The terms such as "connected" or "coupled" do not necessarily refer to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms "upper", "lower", "left", "right", "top", or "bottom", etc. are only used to represent relative positional relationships, and when the absolute position of the object being described 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 there may be intermediate elements.

[0036] A grating fast imaging system is described in the present disclosure, which uses N rows of detectors and a grating placed in front of (upstream of) the detectors to extract three types of information, namely absorption, phase, and small-angle scattering, from the projection data. Since the grating modulates the rays, for multiple rows of detectors, the units (which can be, for example, pixels) in different detectors receive different modulated rays. For example, the modulated rays have the characteristic of fringes. The modulated rays are "carriers", and the period caused by their shape is different from the period of the N rows of detectors. Different structures are calculated through an information extraction algorithm, and the calculation and solution process can be understood as a process similar to demodulation. First, the application principle of the grating in X-ray transmission imaging is described below.

[0037] Figure 1 (a), (b), (c), and (d) show various grating imaging arrangements, where G1, G2, and G3 represent three gratings, which are respectively arranged between the source S and the object under inspection W, or between the object under inspection W and the detector DT as shown.

[0038] In grating imaging technology, the wave-particle duality of X-rays can be utilized simultaneously to obtain three types of characteristic information, namely absorption, phase, and small-angle scattering. Among them, the absorption and phase information respectively correspond to the imaginary part and the real part of the complex refractive index n:

[0039] n = 1 - δ + iβ (1)

[0040] Among them, the linear attenuation coefficient μ has a linear relationship with the imaginary part β (λ is the wavelength of the X-ray):

[0041]

[0042] The three types of multi-characteristic information, namely absorption, phase Φ, and small-angle scattering, can be regarded as the integrals of the linear attenuation coefficient, the refractive index decrement, and the linear diffusion coefficient respectively (where is the propagation path of the X-ray, Φ and D are both constant values related to the imaging system):

[0043]

[0044] Considering that X-rays usually have an energy spectrum distribution, assuming the normalized energy spectrum distribution is, then formula (3) can be written as:

[0045]

[0046] In Figure 1In (a), the function of grating G1 can be to form a self-imaging fringe image on the subsequent optical path. When X-rays interact with matter, this self-imaging fringe may undergo local distortion and deformation, which is at the micron or even sub-micron scale. Ordinary detectors cannot achieve such a high resolution. Therefore, grating G2 amplifies this signal, and by observing the strength change of the detector signal, three multi-characteristic images of absorption, phase, and small-angle scattering can be extracted. When the X-ray source focus is small enough (such as synchrotron radiation or microfocus X-ray machine), only grating G1 and grating G2 are needed, as shown in Figure 1 (a) and (c).

[0047] When the X-ray source focus size is large (such as a conventional X-ray machine), the resulting blurring effect will cause the imaging effect to deteriorate. Therefore, a grating G0 is added behind the X-ray source. Due to grating G0, the radiation beam emitted by the X-ray source is converted into a series of partially coherent micron-scale linear radiation beams, as shown in Figure 1 (b) and (d).

[0048] The object to be inspected W can be placed between grating G0 and grating G1 ( Figure 1 (b)), or it can also be placed between grating G1 and grating G2 ( Figure 1 (c) and (d)).

[0049] When the object to be inspected W is placed between grating G0 and G1, as shown in Figure 1 (b), stronger phase and small-angle scattering signals can be obtained in this configuration, and the imaging contrast and sensitivity are higher. However, there are also disadvantages, that is, the area of grating G1 is large and the cost is high, and the X-rays passing through the object to be inspected W need to pass through the shielding of grating G1 and G2 to be received by the detector, and its X-ray utilization rate is low.

[0050] When the object to be inspected W is placed between grating G1 and G2, as shown in Figure 1 (c) and (d), in this configuration, grating G1 is close to the light source, with a small area and low cost. The X-rays passing through the object to be inspected W are only blocked by grating G2, and the X-ray utilization rate is higher. However, there are also disadvantages. The obtained phase and small-angle scattering signals are weakened, but this is not easy to cause detector signal saturation for some strongly scattering substances.

[0051] The absorption image (T on top) reflects the attenuation characteristics of the substance to X-rays, corresponding to the imaginary part β of the complex refractive index of the substance in X-rays (complex refractive index n = 1 - δ + iβ); the phase image reflects the refraction effect of the substance to X-rays, corresponding to the real part δ of the complex refractive index of the substance in X-rays. Its beneficial effect is that for weakly absorbing substances, the contrast of the phase image is higher than that of the absorption image, and δ can be 2 to 3 orders of magnitude higher than β. Therefore, weakly absorbing substances can be more clearly displayed through the phase image; the small-angle scattering image reflects the structural information of the mesoscopic size of the substance, is very sensitive to the differences at the micron or sub-micron scale such as porosity and multi-fibers, and can break through the limitation of the resolution ability of absorption imaging. The phase and small-angle scattering images are good supplements to the absorption image, can effectively improve the overall imaging effect and resolution ability of the object W to be inspected, and improve the adaptability and accuracy of the inspection process for different substances.

[0052] Figure 7 Shows the absorption t(a), phase Φ(b) and small-angle scattering D(c) two-dimensional images, and the XY plane slice images (corresponding to formula (3) in the disclosure) of the three-dimensional images of the linear attenuation coefficient μ(d), refractive index decrement δ(e), and linear diffusion coefficient v(f) obtained by reconstructing 360 projections collected in one rotation using the FBP algorithm. The absorption image reflecting the attenuation characteristics of the substance (corresponding to the linear attenuation coefficient μ); the phase image with higher contrast for weakly absorbing substances (corresponding to the refractive index decrement δ in the complex refractive index), reflecting the texture information of the internal and external structures of the object W to be inspected; and the small-angle scattering image reflecting the mesoscopic scale structural information of the substance (corresponding to the linear diffusion coefficient v), reflecting the microscopic structures such as porosity and multi-fibers at the micron / sub-micron scale.

[0053] In the traditional grating imaging system, the object W to be inspected needs to be stopped, and then one of the three gratings is moved to obtain the displacement curve corresponding to each pixel point, so as to extract the three kinds of information of absorption, phase and small-angle scattering of each pixel point.

[0054] For example, as Figure 2 (a) shows, the object W to be inspected remains stationary, and one of the gratings (such as grating G2) is moved. Multiple measurement results can be obtained for each detector pixel, corresponding to Figure 2 the displacement curve in b. The result obtained during scanning without an object is called the "background displacement curve", and the result obtained during scanning in the presence of an object is called the "object displacement curve". These two displacement curves are used to extract three kinds of multi-characteristic image information.

[0055] The disadvantage of this method is that it requires moving the grating and the scanning time is too long, so it is not suitable for actual application requirements.

[0056] AsFigure 3 As shown, according to an 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. In Figure 3 the detectors DT and the grating G are shown together as DT-G, but in fact both are discrete components. Figure 3 This is only for schematically showing the arrangement of the multiple rows of detectors DT. In addition, Figure 3 in the figure, the Z direction is the direction in which the multiple rows of detectors DT are arranged. For example, 5 rows of detectors DT are arranged along the Z direction. Figure 3 The detectors shown in the figure can be considered as the ends of each row of detectors DT. The grating G is arranged near the detectors DT. For example, the grating G is arranged adjacent to the detectors DT and extends along the Z direction. In one embodiment, the grating G is arranged parallel to the multiple rows of detectors DT.

[0057] For the convenience of description in the present disclosure, "N rows" is used to represent multiple rows, where N is an integer greater than 1, such as 2, 3, 4, 5, 6, 7, or a larger integer. Figure 3 The example shown is the case where N is 5. The appropriate integer for N rows of detectors can be determined according to needs and cost considerations. In addition, in the description, i is used as an integer from 1 to N, indicating a certain row of the N rows of detectors. Those skilled in the art understand this common usage in mathematics. It should be noted that the use of N rows to represent the concept of multiple rows here is only for the convenience of description and has no other special meaning. The radiation source S can emit a radiation beam, such as an X-ray source, which emits an X-ray beam. Here, the radiation source S can be equipped with a collimator itself, which provides a radiation beam with a desired shape or form. The N rows of detectors are configured to receive the radiation beam from the radiation source S and sense properties such as the intensity of the radiation beam using radiation-sensitive elements. The radiation source S and the detectors define an inspection channel. The object to be inspected W can receive the irradiation of the radiation source S on the inspection channel, and the radiation beam transmitted through the object to be inspected W is detected by the N rows of detectors, so as to determine various properties and contours of the object to be inspected W.

[0058] Each row of the N rows of detectors extends along the transverse direction (perpendicular to the Y-Z plane) of the inspection channel, and the N rows of detectors are arranged along the extension direction (Z direction) of the inspection channel. For example, as Figure 3 shown, the arrow in the figure shows the extension direction of the inspection channel, which is also the moving direction of the object to be inspected W in the inspection channel, that is, the Z direction. The N rows of detectors are arranged along the direction of the arrow (Z direction). Figure 3 In the figure, 5 rows of detectors are shown arranged along the inspection channel. Each row of detectors DT extends along the transverse direction of the inspection channel. In Figure 3 the cross-sectional schematic diagram shown, what can be seen is the end face of each row of detectors, and each row of detectors DT extends from the paper surface into the paper surface. Figure 3It is shown that the 5 rows of detectors are closely arranged, that is, adjacent detectors are adjacent to each other; however, in other embodiments, adjacent rows of detectors may be spaced apart, or there is a gap between the detectors.

[0059] In an embodiment of the present disclosure, the grating imaging device includes at least one grating disposed between the radiation source S and the detector in the inspection channel. The at least one grating has a periodic structure configured to diffract the rays passing through the periodic structure of the grating to form an interference pattern. The periodic structure can be, for example, periodic slits, or it can be said that the structural unit of the periodic structure can be a slit, and when rays or light pass through the slit, a diffraction phenomenon will occur, and the rays or light will thus be changed. To a certain extent, it can be considered that the rays are modulated by the periodic structure. Here, the periodic structure can be, for example, a slit. Taking the periodic structure being a slit as an example, the period 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. When its extension direction forms a very small angle (e.g., relative to the case parallel to the inspection channel), such as 10 - 4 degrees, the interference fringes or moiré fringes generated by the periodic structure formed by the arrangement of multiple slits will change greatly. Therefore, as long as the extension direction of a single slit forms a very small angle with the inspection channel, the requirements of the present invention 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). At this time, the arrangement direction of the slits (i.e., the period direction of the periodic structure) is parallel to the extension direction of the inspection channel, or it can be said that the arrangement direction of the slits is along the Z direction. In other embodiments, the periodic structure can be other structures rather than slits, for example, it can be a material capable of generating a fringe pattern, etc. Figure 3 In the figure, the detector and the grating are shown as an integral body for the convenience of representing the arrangement of the detector and the movement of the object to be inspected W. In fact, the grating can be located at an upstream position facing the radiation beam of the detector, for example, close to the detector, or at a position at a certain distance from the detector, for example, between the object to be inspected W and the source S.

[0060] In the present invention, the at least one grating can be a single grating, for example, arranged adjacent to the detector, that is, the radiation passes through the grating after passing through the object to be inspected W and is then detected by the detector; in another embodiment, the grating can be located between the detector and the object to be inspected W and at a certain distance from the detector.

[0061] In one embodiment, a grating can be provided close to the radiation source S. In one embodiment, the at least one grating can be two gratings, and the two gratings are arranged between the detector and the object to be inspected W; in another embodiment, the two gratings are respectively arranged between the detector and the object to be inspected W and between the object to be inspected W and the radiation source S.

[0062] In one embodiment, at least one grating may be three gratings, with two gratings arranged between the detector and the object under inspection W; one grating arranged between the object under inspection W and the radiation source S; in another embodiment, at least one grating may be three gratings, with one grating arranged between the detector and the object under inspection W; two gratings arranged between the object under inspection W and the radiation source S. Figure 1 Schematic diagrams of various ways of arranging the grating between the radiation source S and the detector are given. In the invention, the grating may have a grating surface.

[0063] In one embodiment, a first grating is arranged between the object under inspection and the N rows of detectors. In one embodiment, a second grating is arranged between the object under inspection and the radiation source. In one embodiment, a third grating is arranged between the object under inspection and the N rows of detectors, where the distance between the third grating and the first grating and the N rows of detectors is different. Regarding the above gratings, in order not to make the drawings complicated, the specific forms of the gratings are not shown in the drawings. However, reference may be made to the foregoing Figure 1 The embodiments of the present invention can be implemented according to the arrangement forms of the gratings.

[0064] In one embodiment of the present disclosure, during the process of detecting the object under inspection W, the object under inspection W can move. The exposure and imaging methods during the moving process are described below. Assume that the uniform motion speed of the object under inspection W is v, and the time interval between two exposures is Δt. Then the displacement of the object under inspection W within the two-exposure time interval is l = vΔt; assume that the intermediate distance between adjacent rows of detectors is Δ det , according to the scanning method of the grating imaging device in this embodiment, the following relationship is satisfied:

[0065] △ det v·△t (5)

[0066] The meaning of the above formula is as follows: within the time interval between the start times of two exposures, the corresponding part or unit of the object under inspection W just moves a distance equal to the pitch between adjacent rows of detectors (i.e., the distance between the front edges of two adjacent rows of detectors, or the distance between their centers or rear edges), so as to ensure 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 forth) detect the same part or unit of the scanned object. Here, it should be noted that exposure refers to the process of turning on the detectors to detect radiation signals until turning off the detectors to end the detection. During this process, the radiation source S can continuously irradiate the object under inspection W; it can also be in the form of pulsed emission and be consistent or inconsistent with the detection time of the detectors, but the radiation source S does not continuously irradiate the object under inspection W. It should be noted here that the above relationship between movement and exposure can actually be for a part or a unit of the object under inspection, not referring to the total number of exposures of the entire object under inspection, because when the volume of the object under inspection is large, during the process of the object under inspection passing through, for example Figure 3 the 5 rows of detectors shown, the number of exposures will obviously be greater than 5 times.

[0067] In one embodiment, in the embodiment of intermittent exposure, the time period of each exposure cycle includes exposure time and remaining time. 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 under inspection W can be irradiated with a pulsed radiation beam during the exposure time, while during the remaining time (before the start of the next exposure), the object under inspection W continues to move, but is not irradiated with rays.

[0068] For any detector pixel, its signal intensity can be expressed as a cosine function:

[0069]

[0070] In the above formula, i represents the i-th pixel in the j-th row of detector pixels, and k represents the number of the exposure. For the same pixel, is only related to the pixel and has nothing to do with the object under inspection W, and is called the "detector constant", while T k , D k , φ k are only related to the object under inspection W and have nothing to do with the pixel itself, and are called the "multi-characteristic information", which are respectively related to absorption, small-angle scattering and phase information. When the object under inspection W is not placed in the channel, T k = 1, D k = 1, φ k = 0, that is:

[0071]

[0072] In an embodiment of the present invention, the object under inspection W can move. During the movement of the object under inspection W, the radiation source S emits a radiation beam to expose the object under inspection W, wherein the moving speed of the object under inspection W is coordinated with the interval of the detectors such that the distance moved by the object under inspection W within the time interval from the start time of the first exposure to the start time of the second exposure is equal to the spacing between the leading edges (or trailing edges) of adjacent detectors.

[0073] When the object under inspection W moves as described above, the first extraction algorithm is applied for data processing. As Figure 4 shown, 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, respectively using the above equation (3), each exposure data can be substituted into one equation. At least three exposure data are required to construct a system of equations, and the optimization method is used to solve the system of equations to obtain the results of absorption T, phase Φ, and small-angle scattering D. Here, those skilled in the art can also use other known solution methods to solve the system of equations, such as Fourier transform, etc. to solve the system of equations.

[0074] In an embodiment of the present disclosure, the object under inspection W is statically placed in the inspection channel. As Figure 5 shown, the object under inspection W is exposed once, and the exposure data of each corresponding row of detectors are collected through N rows of detectors. At this time, the second extraction algorithm is applied for data processing. Specifically, as Figure 6 shown, based on the first set of exposure data of the first row of detectors, the second set of exposure data of the second row of detectors, and the Nth set of exposure data of the Nth row of detectors obtained from the same exposure, it is considered at this time that several adjacent unknown variables can be regarded as the same ("spatial downsampling"). Therefore, the corresponding sets of exposure data of several adjacent rows of detectors can be used, for example, the three sets of exposure data of three adjacent rows of detectors as a combination to solve the system of equations. In other embodiments, the exposure data of M adjacent rows of detectors among the N rows of detectors can also be extracted and combined into a set of exposure data to obtain N - M + 1 sets of exposure data, and at least one of the absorption image, phase image, and small-angle scattering image related to at least part of the object under inspection W is generated based on the N - M + 1 sets of exposure data.

[0075] 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, for the imaging process under certain imaging conditions, the spatial distribution of the phase information Φ or the small-angle scattering information D of the object to be inspected changes relatively slowly or the signal is relatively weak, so it can be regarded as a constant. During the information extraction process, only two unknown quantities need to be considered. For example, in one embodiment, if the spatial distribution of the phase information Φ changes slowly or the signal is relatively weak, only the absorption information T and the small-angle scattering information D are considered; in one embodiment, if the spatial distribution of the small-angle scattering information D changes slowly or the signal is relatively weak, only the absorption information T and the phase information Φ are considered. In these embodiments, only 2 rows of detectors (in the case of N = 2) are required, and the data acquisition process is the same as that in the case of N ≥ 3, except that the number of detector rows is reduced.

[0076] In the present disclosure, a radiation imaging method is provided, including: irradiating an object to be inspected W with a radiation source S; and using N rows of detectors to receive the radiation beam from the radiation source S, wherein the radiation source S and the N rows of detectors define an inspection channel, and N is an integer greater than 1. In this embodiment, each row of the N rows of detectors extends transversely along the inspection channel, the N rows of detectors are arranged along the extending direction of the inspection channel, at least one grating extends in a plane substantially parallel to the plane in which the N rows of detectors are arranged, and the at least one grating has a periodic structure, the periodic structure is configured to diffract the rays passing through the periodic structure of the grating to form an interference pattern, and the extending direction of the structural unit of the periodic structure forms a non-zero angle with the extending direction of the inspection channel.

[0077] In one embodiment, the object to be inspected W moves along the inspection channel in the inspection channel, or the object to be inspected W is statically placed in the inspection channel.

[0078] When the object to be inspected W moves in the inspection channel, multiple exposures are completed, 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 related to at least a partial area of the object to be inspected W; in the case where the object to be inspected W is statically placed in 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 related to at least a partial area of the object to be inspected W based on N - M + 1 sets of exposure data. For specific details, reference can be made to the foregoing content.

[0079] It should be understood that, according to the embodiments of the present disclosure, the object to be inspected W can be moved and then stationary in the inspection channel. In this case, a first extraction algorithm can be applied to the exposure data collected when the object to be inspected W is moving to generate at least one of an absorption image, a phase image, and a small-angle scattering image related to at least a part of the object to be inspected W; a second extraction algorithm can be applied when the object to be inspected W is stationary in the inspection channel to generate at least one of an absorption image, a phase image, and a small-angle scattering image related to at least a part of the object to be inspected W. In this embodiment, at least one of the absorption image, the phase image, and the small-angle scattering image obtained by the two calculations can be compared and mutually verified to improve the accuracy of the inspection.

[0080] It should be understood that the various forms of the processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in the present invention can be executed in parallel, sequentially, or in a different order, as long as the desired results of the technical solutions disclosed in the present invention can be achieved, and no limitation is made herein.

[0081] In the technical solutions of the present disclosure, the collection, storage, use, processing, transmission, provision, and disclosure of the user's personal information and other processing are all in compliance with the provisions of relevant laws and regulations and do not violate public order and good customs.

[0082] The above specific embodiments do not constitute a limitation on the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

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

2. The radiation imaging device according to claim 1, configured to, when the object to be inspected moves on the inspection channel, emit N radiation beams through the radiation source while the N rows of detectors detect the radiation signals of the portions passing through the object to be inspected, and perform N exposures on the portions of the object to be inspected, the number of exposures being the same as the number of rows of detectors.

3. The radiation imaging device according to claim 2, wherein the exposure is an intermittent exposure, and during the interval between the start times of two adjacent exposures, the moving distance of the portion 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 intermittent 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, based on the exposure data of the first row of the N rows of detectors at the first exposure, the exposure data of the i-th row of the N rows of detectors at the i-th exposure, and the exposure data of other multiple completed exposures, as the exposure data related to the portion area 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, where i is an integer and 1 < i ≤ N.

5. The radiation imaging device according to claim 1, configured to, when the object to be inspected is stationary on the inspection channel, emit the radiation beam through the radiation source to irradiate the object to be inspected, and the N rows of detectors detect the radiation signals passing through the object to be inspected to perform an exposure on the object to be inspected.

6. The radiation imaging device according to claim 5, wherein the radiation imaging device is configured to, for at least a partial area of the object to be inspected, apply a second extraction algorithm based on the exposure data of each row of the N rows of detectors, so as to extract and combine the exposure data of adjacent M rows of detectors in the N rows of detectors into a set of exposure data, obtain N - M + 1 sets 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 sets of exposure data, where M is an integer and 1 ≤ M ≤ N.

7. The radiation imaging device according to claim 1, wherein the at least one grating includes a first grating disposed between the object to be examined and the N rows of detectors.

8. The radiation imaging device according to claim 7, wherein the at least one grating includes a second grating disposed between the object to be examined and the radiation source.

9. The radiation imaging device according to claim 8, wherein the at least one grating further includes a third grating disposed between the object to be examined and the N rows of detectors, and 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 or arranged adjacent to each other along the inspection channel.

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 to be examined.

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 perform multiple exposures on the object to be examined.

13. A radiation imaging method, comprising: irradiating an object to be examined with a radiation source; and receiving radiation beams from the radiation source using N rows of detectors, wherein the radiation source and the N rows of detectors define an inspection channel, and N is an integer greater than 1; wherein each row of the N rows of detectors extends transversely to the inspection channel, the N rows of detectors are arranged along the extending 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 configured to diffract the rays passing through the periodic structure of the grating to form an interference pattern, and the extending direction of the structural unit of the periodic structure forms a non-zero angle with the extending direction of the inspection channel.

14. The radiation imaging method according to claim 13, wherein the object to be examined moves along the inspection channel in the inspection channel or the object to be examined is statically placed in the inspection channel.

Images