Radiation inspection device and tomographic image generation method

Abstract

To provide a radiation inspection device and a tomographic image generation method capable of inspecting multiple subjects efficiently and highly accurately.SOLUTION: A radiation inspection device 1 comprises: a radiation source 21 that irradiates radiation in an optical-axis direction; a detector 22 having a detection region 22a for radiation irradiated by the radiation source 21; a support section 23 that supports a plurality of subjects W; an imaging control unit 41 that causes the radiation source 21, the detector 22 and the support section 23 to rotate relatively about a rotation axis P1 by rotationally driving a rotation drive mechanism 25, and acquires projection data DP1 by the detector 22 by irradiating the radiation from the radiation source 21 so as to pass through both a portion T1 of the first subject W1 and a portion T2 of the second subject W2; and a reconstruction unit 51 that reconstructs partial tomographic images of the first subject W1 and the second subject W2 on the basis of the projection data DP1.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a radiological inspection apparatus and a tomographic image generating method for obtaining a tomographic image of a subject by irradiating the subject with radiation. [Background technology]

[0002] A radiological inspection apparatus is known that irradiates a subject with radiation from a radiation source while rotating the subject on a rotary table, and obtains a tomographic image of the subject based on radiation projection data obtained from multiple directions. In such a radiological inspection apparatus, a technique that uses X-rays as radiation is called X-ray CT (Computed Tomography).

[0003] Tomographic images obtained by a radiological inspection device are used, for example, in nondestructive testing. For example, Patent Document 1 discloses a battery inspection device that inspects the misalignment of electrode plates of a battery having a stack of multiple rectangular electrode plates. The battery inspection device of Patent Document 1 inspects the misalignment of the electrode plates of the battery as follows. First, the battery inspection device of Patent Document 1 irradiates a first corner of the four corners of the electrode plate with a radiation beam in a direction along the surface of the electrode plate and inclined relative to the side to obtain a first transmission image, and irradiates a second corner of the electrode plate with a radiation beam in a direction along the surface of the electrode plate and inclined relative to the side to obtain a second transmission image. Furthermore, the battery inspection device of Patent Document 1 determines the protrusion length of the negative electrode plate of each layer relative to the positive electrode plate in each of the first and second transmission images. Furthermore, it determines whether the protrusion length of each layer in each of the first and second transmission images is within an allowable range. If the protrusion length is within the allowable range in all layers of the first transmission image and the second transmission image, the battery is determined to be a non-defective product. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-039014 Summary of the Invention [Problem to be solved by the invention]

[0005] Meanwhile, mass production lines are required to efficiently and accurately inspect test objects such as batteries. In contrast, the battery inspection device of Patent Document 1 inspects test objects one by one. Therefore, it takes time to inspect all test objects, corresponding to the number of test objects. Furthermore, performing parallel inspections using multiple battery inspection devices can be difficult from the perspectives of the investment required for installation and the allocation of personnel to operate the battery inspection devices.

[0006] An object of the present invention is to provide a radiological inspection apparatus and a tomographic image generating method that can inspect a plurality of subjects efficiently and accurately. [Means for solving the problem]

[0007] A radiation inspection apparatus according to a first aspect is an apparatus for generating a tomographic image based on projection data obtained by irradiating a subject with radiation. The radiation inspection apparatus includes a radiation source that irradiates radiation in an optical axis direction, a detector having a detection area for the radiation irradiated by the radiation source, a support unit that is located between the radiation source and the detector and that supports a first subject and a second subject among the multiple subjects in a state where they are lined up in a first direction that intersects with the optical axis direction, a rotation drive mechanism that rotates the support unit relative to the radiation source and the detector around a rotation axis that intersects with the first direction, and a detector that rotates the support unit relative to the radiation source and the detector around a rotation axis that intersects with the first direction. an imaging control unit that acquires projection data by the detector by irradiating the radiation from the radiation source while rotating the radiation source, the detector, and the support unit relatively about the rotation axis by the rotation drive mechanism so that the radiation passes through both at least a portion of the first subject and at least a portion of the second subject, with the optical axis direction intersecting both the first direction and the rotation axis; and a reconstruction unit that reconstructs tomographic images of at least a portion of each of the first subject and the second subject based on the projection data.

[0008] In the above-described configuration, the radiation source and the detector are positioned such that the optical axis of the radiation source intersects the rotation axis of the rotary drive mechanism. The support unit supports a first subject and a second subject among the multiple subjects in a state where they are aligned in a first direction that intersects both the rotation axis and the optical axis direction. Therefore, the radiation source can irradiate the radiation so that the radiation passes through both the first subject located on one side of the rotation axis in the first direction and the second subject located on the other side of the rotation axis at an angle to the axial direction of the rotation axis.

[0009] The reconstruction unit reconstructs a tomographic image of at least a portion of each of the first subject and the second subject based on projection data obtained by detecting, with the detector, radiation irradiated so as to pass through at least a portion of each of the first subject and the second subject.

[0010] Therefore, two tomographic images including a tomographic image of at least a part of the first subject and a tomographic image of at least a part of the second subject can be reconstructed based on projection images acquired by a single imaging. Furthermore, since projection data is acquired by detecting the radiation that passes through the first subject and the second subject obliquely to the axial direction along which the rotation axis extends, three-dimensional tomographic images can be reconstructed based on information about the axial direction of the first subject and the second subject.

[0011] As a result, it is possible to efficiently obtain high-precision tomographic images of a plurality of subjects, thereby providing a radiological inspection apparatus capable of inspecting a plurality of subjects efficiently and with high precision.

[0012] A radiological inspection apparatus according to aspect 2 is the same as aspect 1, wherein each of the plurality of subjects is a rectangular parallelepiped, the first subject and the second subject are positioned side by side in the first direction, and the imaging control unit irradiates the radiation from the radiation source so that the radiation passes through both the other end of the first subject in the first direction and one end of the second subject in the first direction, thereby acquiring projection data with the detector.

[0013] With the above-described configuration, it is possible to efficiently obtain tomographic images of the ends of two rectangular parallelepiped objects, thereby providing a radiological inspection apparatus capable of inspecting multiple objects efficiently and accurately.

[0014] A radiological inspection apparatus according to a third aspect is related to the second aspect, wherein the first direction and the axial direction in which the rotation axis extends are orthogonal. The multiple subjects are aligned in the first direction and a second direction orthogonal to the axial direction and the first direction when viewed in the axial direction. The first subject among the multiple subjects is positioned on one side of the second direction relative to the rotation axis when viewed in the axial direction. The second subject is positioned adjacent to the first subject on the other side of the first direction when viewed in the axial direction, and is positioned on one side of the second direction relative to the rotation axis. The third subject is positioned adjacent to the first subject on the other side of the second direction when viewed in the axial direction, and is positioned on the other side of the second direction relative to the rotation axis. The fourth subject is positioned adjacent to the second subject on the other side of the second direction when viewed in the axial direction, and is positioned on the other side of the second direction relative to the rotation axis. The imaging control unit irradiates the radiation from the radiation source so as to pass through four corners, including a first corner located on the other side of the first subject in the first direction and on the other side of the second direction of the first subject, a second corner located on one side of the second subject in the first direction and on the other side of the second direction of the second subject, a third corner located on the other side of the third subject in the first direction and on one side of the second direction of the third subject, and a fourth corner located on one side of the fourth subject in the first direction and on one side of the second direction of the fourth subject, to obtain projection data with the detector. The reconstruction unit reconstructs tomographic images of the four corners based on the projection data.

[0015] In the above configuration, the object to be examined is a rectangular parallelepiped, and with the above configuration, it is possible to efficiently obtain high-precision tomographic images of each corner of the four objects to be examined that are arranged in a grid pattern.

[0016] A fourth aspect of the present invention relates to the radiological inspection apparatus of the third aspect, wherein the subject is a battery in which electrode plates are stacked with the axial direction as the stacking direction.

[0017] According to the above-described configuration, it is possible to obtain a tomographic image of a battery in which electrode plates are stacked, thereby improving the efficiency of battery inspection.

[0018] The radiological inspection apparatus according to a fifth aspect is in accordance with the fourth aspect, further comprising a displacement detection unit that detects a stacking displacement of the electrode plates at at least one of the four corner portions based on the tomographic image.

[0019] According to the above-described configuration, it is possible to detect stacking misalignment of electrode plates of a battery as an object to be inspected, thereby improving the efficiency of inspection for stacking misalignment of electrode plates of a battery.

[0020] A radiological inspection apparatus according to a sixth aspect is the same as that of the fifth aspect, further comprising an information assigning unit that assigns identification information of the subject and corner identification information for identifying the corners in the subject to the four corners reconstructed by the reconstruction unit. The misalignment detection unit detects the stack misalignment based on the identification information and the corner identification information.

[0021] According to the above-described configuration, it is possible to identify which of a plurality of test specimens has had a stacking misalignment detected, and to identify which corner of the test specimen the stacking misalignment is detected in. Therefore, it is possible to identify the test specimen and corner in which the stacking misalignment is detected.

[0022] A radiation inspection apparatus according to aspect 7 is any one of aspects 3 to 6, wherein the detector has a plurality of detection regions aligned in the first direction and the second direction and located on one side of the detector, the plurality of detection regions including a first detection region that detects radiation passing through the first corner portion of the first object, a second detection region that detects radiation passing through the second corner portion of the second object, a third detection region that detects radiation passing through the third corner portion of the third object, and a fourth detection region that detects radiation passing through the fourth corner portion of the fourth object.

[0023] In the above-described configuration, no radiation detection data is generated in positions between the four detection regions, the first, second, third, and fourth, which are aligned on one surface of the detector. This reduces the amount of projection data, thereby reducing the calculation load on the reconstruction unit.

[0024] A tomographic image generating method according to an eighth aspect is a method for generating a tomographic image using a radiological examination apparatus that includes: a radiation source that irradiates radiation in an optical axis direction; a detector having a detection area for the radiation irradiated by the radiation source; and a support unit that is positioned between the radiation source and the detector and supports a subject, wherein the support unit is rotationally driven relative to the radiation source and the detector around a rotation axis that intersects with the optical axis direction; and the tomographic image is generated based on projection data obtained by irradiating the subject with radiation. The tomographic image generating method includes: a supporting step of supporting a first subject and a second subject among the plurality of subjects by the supporting unit while the first subject is positioned on one side of the first direction with respect to the rotation axis and the second subject is positioned on the other side of the first direction with respect to the rotation axis, and the optical axis direction intersects both the first direction and the rotation axis; a projection data acquiring step of irradiating the radiation from the radiation source while rotating the radiation source, the detector, and the supporting unit relatively about the rotation axis so that the radiation passes through both at least a portion of the first subject and at least a portion of the second subject, thereby acquiring projection data with the detector; and a reconstruction step of reconstructing tomographic images of at least a portion of each of the first subject and the second subject based on the projection data.

[0025] In the above-described configuration, the radiation source and the detector are positioned such that the optical axis of the radiation source intersects both a first direction in which the first and second subjects supported by the support are arranged and the rotation axis of the rotation drive mechanism. Furthermore, the radiation source, the detector, and the support are rotated relative to each other about the rotation axis so that the radiation passes through both at least a portion of the first subject and at least a portion of the second subject, and the radiation is irradiated from the radiation source obliquely with respect to the rotation axis, thereby enabling projection data to be acquired by the detector.

[0026] Furthermore, based on the projection data thus acquired, tomographic images of at least a part of each of the first and second subjects are reconstructed.

[0027] Therefore, two tomographic images, i.e., a tomographic image of at least a part of the first subject and a tomographic image of at least a part of the second subject, can be reconstructed based on projection images acquired by a single imaging. Furthermore, projection data is acquired by detecting the radiation that passes through the first subject and the second subject obliquely in the axial direction along which the rotation axis extends, so that three-dimensional tomographic images can be reconstructed based on information on the axial direction of the first subject and the second subject.

[0028] As a result, highly accurate tomographic images can be obtained efficiently for a plurality of subjects. [Effects of the Invention]

[0029] In a radiological examination apparatus according to one aspect of the present invention, an imaging control unit rotates the rotation drive mechanism in a state in which the first subject is located on one side of the first direction relative to the rotation axis, the second subject is located on the other side of the first direction relative to the rotation axis, and the optical axis direction intersects both the first direction and the axial direction along which the rotation axis extends, thereby rotating the radiation source, the detector, and the support unit relatively around the rotation axis, and irradiating the radiation from the radiation source such that the radiation passes through both at least a portion of the first subject and at least a portion of the second subject, thereby acquiring projection data with the detector.

[0030] According to the above-described aspect, it is possible to provide a radiological inspection apparatus capable of inspecting a plurality of subjects efficiently and accurately. [Brief explanation of the drawings]

[0031] [Figure 1] FIG. 1 is a functional block diagram showing a schematic configuration of a radiological inspection apparatus according to the first embodiment. [Figure 2] FIG. 2 is a flowchart showing the flow of a tomographic image generating method using a radiological inspection apparatus. [Figure 3] FIG. 3 is a functional block diagram showing a schematic configuration of a radiological inspection apparatus according to the second embodiment. [Figure 4] FIG. 4 is a side view showing a schematic configuration of a radiological inspection apparatus according to the second embodiment. [Figure 5] FIG. 5 is a plan view showing a schematic configuration of a radiological inspection apparatus according to the second embodiment. [Figure 6] FIG. 6 is a diagram showing an example of a reconstructed image generated by the reconstruction unit. [Figure 7] FIG. 7 is a plan view illustrating the imaging method performed by the imaging control unit. [Figure 8] FIG. 8 is a diagram illustrating an example of a method for detecting stack misalignment by the misalignment detection unit. [Figure 9] FIG. 9 is a diagram illustrating another example of a method for detecting stack misalignment by the misalignment detection unit. [Figure 10] FIG. 10 is a diagram illustrating yet another example of a method for detecting stack misalignment by the misalignment detection unit. [Figure 11] FIG. 11 is a functional block diagram showing a schematic configuration of a radiological inspection apparatus according to the third embodiment. [Figure 12] FIG. 12 is a side view showing a schematic configuration of a radiological inspection apparatus according to the third embodiment. [Figure 13] FIG. 13 is a side view showing a schematic configuration of a radiological inspection apparatus according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0032] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same or corresponding parts in the drawings are designated by the same reference numerals, and their description will not be repeated. Furthermore, the dimensions of the components in each drawing do not faithfully represent the actual dimensions of the components, the dimensional ratios of the components, etc.

[0033] In each figure, arrow X indicates the X-axis in the coordinate system of the radiological inspection apparatuses 1, 2, 3, and 4, arrow Y indicates the Y-axis in the coordinate system of the radiological inspection apparatuses 1, 2, 3, and 4, and arrow Z indicates the Z-axis in the coordinate system of the radiological inspection apparatuses 1, 2, 3, and 4. For each of the X-axis, Y-axis, and Z-axis, the direction of the arrow is the positive direction, and the direction opposite to the arrow is the negative direction. The X-axis and Y-axis are axes extending horizontally of the radiological inspection apparatuses 1, 2, 3, and 4. The Z-axis is an axis extending vertically of the radiological inspection apparatuses 1, 2, 3, and 4. Hereinafter, the vertical direction of the radiological inspection apparatuses 1, 2, 3, and 4 will be simply referred to as the vertical direction. For each of the X-axis, Y-axis, and Z-axis, the direction of the arrow will be referred to as one side, and the direction opposite to the arrow will be referred to as the other side. The Z-axis is perpendicular to a horizontal plane including the X-axis and Y-axis.

[0034] [Embodiment 1] (Overall composition) 1 is a functional block diagram showing a schematic configuration of a radiological inspection apparatus 1 according to embodiment 1. The radiological inspection apparatus 1 is an X-ray CT apparatus that generates tomographic images based on projection data obtained by irradiating a plurality of subjects W with radiation.

[0035] As shown in FIG. 1, the radiological inspection device 1 includes a radiation source 21, a detector 22, a support unit 23, a rotation drive mechanism 25, a memory unit 30, an imaging control unit 41, a reconstruction unit 51, an operation unit 61, and a display unit 62.

[0036] The radiation source 21 emits radiation in the optical axis direction. The radiation is, for example, X-rays. The radiation source 21 emits a cone beam of X-rays toward the detector 22 located in one direction of the optical axis Q1. The radiation source 21 includes a microfocus X-ray tube with a focal point of several micrometers to several tens of micrometers. In a microfocus X-ray tube, electrons generated from a filament are focused and then directed toward an anode, which is a target, to generate X-rays.

[0037] The detector 22 is located on one side of the optical axis direction relative to the radiation source 21. The detector 22 has a detection area for the radiation irradiated by the radiation source 21 on one surface 22a. The detector 22 is, for example, a two-dimensional X-ray detector having pixels arranged two-dimensionally. The detection area of the detector 22 is, for example, parallel to the XY plane. That is, the detection area of the detector 22 may obliquely intersect with the optical axis Q1. The detector 22 generates projection data DP1 based on the detected radiation.

[0038] The support unit 23 supports a plurality of subjects W. The plurality of subjects W include a first subject W1 and a second subject W2. The support unit 23 is, for example, a table capable of supporting the first subject W1 and the second subject W2. The support unit 23 has a placement surface 23a parallel to the XY plane. The support unit 23 is capable of placing a plurality of subjects W on the placement surface 23a. The support unit 23 is located between the radiation source 21 and the detector 22. The support unit 23 supports the first subject W1 and the second subject W2 at positions where the first subject W1 and the second subject W2 are aligned in a first horizontal direction (first direction) that intersects with the optical axis direction.

[0039] The rotation drive mechanism 25 drives the support unit 23 to rotate relative to the radiation source 21 and the detector 22 around a rotation axis P1 that extends in an axial direction perpendicular to the first horizontal direction. The rotation axis P1 extends in the vertical direction. The rotation axis P1 also intersects with the optical axis direction. The angle at which the rotation axis P1 intersects with the optical axis direction may be, for example, 45° or 135°. The radiation source 21 is located at a distance R1 from the rotation axis P1 in one direction perpendicular to the rotation axis P1. The radiation source 21 has a rotational orbit B1 around the rotation axis P1. That is, the rotational radius of the rotational orbit B1 is R1. The detector 22 is located at a distance R2 from the rotation axis P1 in another direction opposite to the one direction. The detector 22 has a rotational orbit B2 around the rotation axis P1. That is, the rotational radius of the rotational orbit B2 is R2. Note that the distance of the detector 22 from the rotation axis P1 is, for example, based on the center of the detector 22.

[0040] As described above, the first subject W1, which is one of the multiple subjects W, and the second subject W2, which is the other, are positioned side by side in the first horizontal direction. The first horizontal direction is parallel to the X-axis. In the following description, one side of the first horizontal direction is the other side of the X-axis direction, and the other side of the first horizontal direction is the other side of the X-axis direction. The second subject W2 is positioned on one side of the X-axis direction relative to the first subject W1. That is, the first subject W1 is positioned on one side of the first horizontal direction (first direction) perpendicular to the rotation axis P1 with respect to the rotation axis P1. The second subject W2 is positioned on the other side of the first horizontal direction with respect to the rotation axis P1. There are no particular limitations on the first subject W1 and the second subject W2 as long as they are subjects that can be inspected by the radiation inspection apparatus 1. As shown in FIG. 1, the first subject W1 and the second subject W2 may have, for example, a cylindrical shape. However, there are no particular limitations on the shapes of the first subject W1 and the second subject W2. The shape of the first test object W1 and the second test object W2 may be, for example, a polygonal prism such as a triangular prism, a quadrangular prism, a hexagonal prism, or an octagonal prism.

[0041] As indicated by solid arrows in FIG. 1 , the rotation drive mechanism 25 drives, for example, the radiation source 21 and the detector 22 to rotate relatively to the support unit 23 at a constant speed around a rotation axis P1. When imaging multiple subjects W, the rotation drive mechanism 25 rotates the radiation source 21 and the detector 22 relative to the support unit 23 on which the multiple subjects W are placed by a predetermined angle or number of times under the control of the imaging control unit 41. The rotation drive mechanism 25 is realized by a driving device such as a motor. The rotation drive mechanism 25 may have a unit that rotates the radiation source 21 and the detector 22 around the rotation axis P1. The unit that rotates the radiation source 21 and the detector 22 around the rotation axis P1 may be separate units for the radiation source 21 and the detector 22, respectively, or may be a single unit that rotates both the radiation source 21 and the detector 22 integrally. The rotation drive mechanism 25 may have a support unit rotation unit that rotates the support unit 23 around the rotation axis P1.

[0042] The storage unit 30 stores various data such as programs executed by the imaging control unit 41 and data used by the programs. The storage unit 30 can be realized, for example, by a volatile or non-volatile storage device. The storage unit 30 can be realized, for example, by an internal or external storage device or removable media. According to another example, the storage unit 30 can be realized by a cache memory and a main storage device. According to yet another example, the storage unit 30 can be realized by an auxiliary storage device such as an SSD (Solid State Drive) or an HDD (Hard Disk). The storage unit 30 also stores projection data DP1 obtained by imaging multiple subjects W at each angle.

[0043] The imaging control unit 41 controls imaging of multiple subjects W using radiation. The imaging control unit 41 realizes various functions by reading out a program stored in the storage unit 30 and executing the read out program using an arithmetic device such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The imaging control unit 41 irradiates radiation from the radiation source 21 while rotating the radiation source 21, the detector 22, and the support unit 23 relatively about the rotation axis P1 using the rotation drive mechanism 25 so that the radiation passes through both a portion T1 of the first subject and a portion T2 of the second subject, with the first subject W1 positioned on one side of the rotation axis P1 in a first horizontal direction and the second subject W2 positioned on the other side of the first horizontal direction with the optical axis direction intersecting both the first horizontal direction and the axial direction, thereby acquiring projection data D1 using the detector 22. That is, the imaging control unit 41 detects the radiation emitted by the radiation source 21 obliquely with respect to the rotation axis P1 using the detector 22, and acquires the projection data D1.

[0044] Based on the projection data DP1, the reconstruction unit 51 reconstructs a plurality of tomographic images of the subject W. For the reconstruction in the reconstruction unit 51, a conventional reconstruction method known as oblique CT can be used.

[0045] The operation unit 61 is a user interface for performing various operations in the radiological inspection apparatus 1. The operation unit 61 can be realized by, for example, an input device such as a keyboard or buttons, or a pointing device such as a mouse, a pen tablet, or a touch panel. For example, an operator can operate the operation unit 61 to perform imaging operations in the radiological inspection apparatus 1.

[0046] The display unit 62 presents to the user various data in the radiation inspection apparatus 1. The display unit 62 can be realized by a display device such as a liquid crystal or organic EL display device.

[0047] (Operation flow of the radiological inspection device) The flow of operations of the radiation inspection apparatus 1 will be described with reference to Fig. 2 in addition to Fig. 1. Fig. 2 is a flowchart showing the flow of a tomographic image generating method S1 performed by the radiation inspection apparatus 1.

[0048] First, in the tomographic image generating method S1, a supporting step S11 is performed in which multiple subjects W are supported by the support unit 23. In the supporting step S11, a first subject W1 and a second subject W2 among the multiple subjects W are supported by the support unit 23 while aligned in a first horizontal direction intersecting with the optical axis direction. The first subject W1 is disposed on one side of the first horizontal direction, which is perpendicular to the rotation axis P1, with respect to the rotation axis P1. The second subject W2 is disposed on the other side of the first horizontal direction. The first subject W1 and the second subject W2 are disposed at positions where radiation from the radiation source 21 can pass through both a portion T1 of the first subject W1 and a portion T2 of the second subject W2. The first subject W1 and the second subject W2 are disposed in a state in which the optical axis direction intersects both the first horizontal direction and the axial direction. The portion T1 of the first subject W1 is, for example, the other end of the first subject W1 in the first horizontal direction. The part T2 of the second object W2 is, for example, one end of the second object W2 in the first horizontal direction.

[0049] Next, a projection data acquisition step S12 is performed to acquire projection data DP1. In the projection data acquisition step S12, the imaging control unit 41 causes the rotation drive mechanism 25 to rotate the radiation source 21, the detector 22, and the support unit 23 relatively around the rotation axis P1, and irradiates radiation from the radiation source 21 so that the radiation passes through both the portion T1 of the first subject W1 and the portion T2 of the second subject W2, thereby acquiring projection data DP1 with the detector 22.

[0050] Next, a reconstruction step S13 is executed in which the reconstruction unit 51 reconstructs sectional images of the part T1 of the first object W1 and the part T2 of the second object W2 based on the projection data DP1.

[0051] In the above-described radiological inspection apparatus 1 and tomographic image generating method S1 using the radiological inspection apparatus 1, the radiation source 21 and the detector 22 are positioned such that the optical axis Q1 of the radiation source 21 intersects the rotation axis P1 of the rotation drive mechanism 25. The support unit 23 supports a first subject W1 and a second subject W2 among the multiple subjects W in a state where they are aligned in a first horizontal direction that intersects both the rotation axis P1 and the optical axis direction. Therefore, the radiation source 21 can irradiate both of the multiple subjects W supported by the support unit 23 with radiation such that the radiation passes through both the first subject W1 located on one side of the first horizontal direction with respect to the rotation axis P1 and the second subject W2 located on the other side of the first horizontal direction with respect to the rotation axis P1, at an angle to the axial direction along which the rotation axis P1 extends.

[0052] The reconstruction unit 51 reconstructs tomographic images of the portion T1 of the first subject W1 and the portion T2 of the second subject W2 based on projection data DP1 obtained by detecting, with the detector 22, radiation irradiated so as to pass through the portion T1 of the first subject W1 and the portion T2 of the second subject W2.

[0053] Therefore, based on the projection data acquired by one imaging, two tomographic images of the subjects, i.e., a tomographic image of a part T1 of the first subject W1 and a tomographic image of a part T2 of the second subject W2, can be reconstructed. Furthermore, since the projection data DP1 is acquired by detecting radiation that passes through the first subject W1 and the second subject W2 obliquely to the axial direction along which the rotation axis extends, three-dimensional tomographic images can be reconstructed based on information about the axial direction of the first subject W1 and the second subject W2.

[0054] As a result, it is possible to efficiently obtain high-precision tomographic images for a plurality of subjects W. Therefore, it is possible to provide a radiological inspection apparatus 1 and a tomographic image generating method S1 that can inspect a plurality of subjects W efficiently and with high precision.

[0055] [Embodiment 2] FIG. 3 is a functional block diagram showing a schematic configuration of a radiological inspection apparatus 2 according to embodiment 2. FIG. 4 is a side view showing a schematic configuration of the radiological inspection apparatus 2 according to embodiment 2. FIG. 5 is a plan view showing a schematic configuration of the radiological inspection apparatus 2 according to embodiment 2. The radiological inspection apparatus 2 according to embodiment 2 inspects batteries. In the description of embodiment 2, detailed description of parts common to embodiment 1 will not be repeated.

[0056] (Overall composition) As shown in FIG. 3, the radiological inspection device 2 includes a radiation source 21, a detector 22, a support unit 231, a rotation drive mechanism 25, a movement mechanism 26, a memory unit 30, an imaging control unit 42, a reconstruction unit 52, an information providing unit 55, a deviation detection unit 56, an operation unit 61, and a display unit 62.

[0057] The support part 231 supports a plurality of inspected objects W. The support part 231 has a placement surface 231a parallel to the XY plane. Each of the inspected objects W has a rectangular parallelepiped shape. In a plan view, each of the inspected objects W has four corner portions located at the four vertices of a quadrangle. Each of the inspected objects W is a battery in which electrode plates are stacked in one direction.

[0058] The multiple subjects W are placed on the placement surface 231a in such a position that the axial direction of the rotation axis P1 coincides with the stacking direction. When viewed in the axial direction, the multiple subjects W are aligned in a grid pattern of 3 rows and 3 columns in a first horizontal direction and a second horizontal direction (second direction) perpendicular to the axial direction and the first horizontal direction. The first horizontal direction is the X-axis direction, and the second horizontal direction is the Y-axis direction. One side of the first horizontal direction is the other side of the X-axis direction, and the other side of the first horizontal direction is the other side of the X-axis direction. Furthermore, one side of the second horizontal direction is the other side of the Y-axis direction, and the other side of the second horizontal direction is the other side of the Y-axis direction. In the following description, the rows of the multiple subjects W aligned in the grid pattern are referred to as the first, second, and third rows in the direction of the X-axis arrow. Furthermore, the columns of the multiple subjects W aligned in the grid pattern are referred to as the first, second, and third columns in the direction of the Y-axis arrow. In addition, when multiple rectangular parallelepiped-shaped objects W are arranged in a grid pattern, it means that when viewed in a plane, the rectangular sides of the objects W are positioned so that they are aligned in the first horizontal direction or the second horizontal direction.

[0059] 5, subjects W1-1, W1-2, and W1-3 are located in the first row of the matrix of multiple subjects W, in order from the first column. Also, subjects W2-1, W2-2, and W2-3 are located in the second row of the matrix of multiple subjects W, in order from the first column. Also, subjects W3-1, W3-2, and W3-3 are located in the third row of the matrix of multiple subjects W, in order from the first column.

[0060] FIG. 4 also shows a partial cross-sectional view of a battery 90 as a test object. As shown in FIG. 4, the battery 90 as a test object includes a case 91, a positive electrode plate 92, and a negative electrode plate 93. The positive electrode plate 92 and the negative electrode plate 93 as electrode plates are located within the case 91. The positive electrode plates 92 and the negative electrode plates 93 are alternately stacked in the stacking direction. For convenience of illustration, in FIG. 4, the test objects W1-1 and W1-2 located on one side of the first horizontal direction with respect to the rotation axis P1 are denoted as "WA." Furthermore, the test objects W2-1 and W2-2 located on the other side of the first horizontal direction with respect to the rotation axis P1 are denoted as "WB."

[0061] Furthermore, as shown in FIG. 4, a radiation passing region RG1 through which the radiation detected by the detector 22 passes among the cone beam radiation emitted from the radiation source 21 overlaps with a part of the negative electrode plate 932 located at the bottom layer in the stacking direction of each of the subjects WA and WB, and a part of the electrode plate 931 located at the top layer in the stacking direction.

[0062] The movement mechanism 26 has a drive mechanism that moves the support unit 231 in the horizontal direction relative to the radiation source 21 and the detector 22. The movement mechanism 26 can be realized by a drive mechanism that converts the rotational drive force of an electric motor, such as a motor, into linear motion and a motion controller board that operates the drive mechanism. The movement mechanism 26 moves the radiation irradiation position in the first horizontal direction, for example, by moving the support unit 231 in a first horizontal direction. The movement mechanism 26 also moves the radiation irradiation position in the second horizontal direction, for example, by moving the support unit 231 in a second horizontal direction. As described above, the movement mechanism 26 moves the radiation irradiation position in the first horizontal direction or the second horizontal direction, thereby changing the four subjects in a 2×2 array that are the imaging targets of the imaging control unit 42 in one imaging session.

[0063] The imaging control unit 42 sets four subjects (2 × 2) as imaging targets in one imaging session. The imaging control unit 42 sets subjects W1-1, W1-2, W2-1, and W2-2 shown in FIG. 5 as imaging targets in one imaging session, for example.

[0064] That is, the subject W1-1 as the first subject is located on one side in the first horizontal direction and on one side in the second horizontal direction with respect to the rotation axis P1 when viewed in the axial direction. The subject W2-1 as the second subject is located adjacent to the subject W1-1 as the first subject on the other side in the first horizontal direction and on one side in the second horizontal direction with respect to the rotation axis P1 when viewed in the axial direction. The subject W1-2 as the third subject is located adjacent to the subject W1-1 as the first subject on the other side in the second horizontal direction and on the other side in the second horizontal direction with respect to the rotation axis P1 when viewed in the axial direction. The subject W2-2 as the fourth subject is located adjacent to the subject W2-1 as the second subject on the other side in the second horizontal direction and on the other side in the second horizontal direction with respect to the rotation axis P1 when viewed in the axial direction.

[0065] The imaging control unit 42 targets two subjects adjacent in the first horizontal direction at one end and the other end in the second horizontal direction of the plurality of subjects W arranged in a grid pattern.

[0066] In addition, in Figure 5, corners of the rectangular object in plan view are labeled A, B, C, and D. Corner A is located at one end in the first horizontal direction and one end in the second horizontal direction. Corner B is located at one end in the first horizontal direction and the other end in the second horizontal direction. Corner C is located at the other end in the first horizontal direction and one end in the second horizontal direction. Corner D is located at the other end in the first horizontal direction and the other end in the second horizontal direction.

[0067] The imaging control unit 42 acquires projection data DP2 generated by the detector 22 that detects radiation irradiated from the radiation source 21 so as to pass obliquely through the center of the four 2×2 arrays of subjects in the planar view.

[0068] For example, radiation irradiated from the radiation source 21 passes through four corners including a corner D (first corner) of the subject W1-1 as the first subject, a corner B (second corner) of the subject W2-1 as the second subject, a corner C (third corner) of the subject W1-2 as the third subject, and a corner A (fourth corner) of the subject W2-2 as the fourth subject. The imaging control unit 42 acquires projection data DP2 based on the results of detection by the detector 22 of the radiation that has passed through these four corners.

[0069] The imaging control unit 42 also controls the moving mechanism 26 to perform the above-described imaging while changing the four subjects in a 2×2 array that are the imaging targets. The imaging method by the imaging control unit 42 will be described in detail later.

[0070] The reconstruction unit 52 reconstructs sectional images of the above-mentioned four corner portions based on the projection data DP2. FIG. 6 is a diagram showing an example of a reconstructed image RP1 generated by the reconstruction unit 52. The reconstructed image RP1 includes a portion T1-1 corresponding to the corner portion D of the subject W1-1, a portion T1-2 corresponding to the corner portion C of the subject W1-2, a portion T2-1 corresponding to the corner portion B of the subject W2-1, and a portion T2-2 corresponding to the corner portion A of the subject W2-2. A sectional image SE1 can be obtained at any cross section of the reconstructed image RP1. The sectional image SE1 can be obtained, for example, at a cross section parallel to the XZ plane in the portion T1-1.

[0071] With the above-described configuration, it is possible to efficiently obtain highly accurate tomographic images of the corners of the four subjects W1-1, W1-2, W2-1, and W2-2 arranged in a grid pattern.

[0072] The information assigning unit 55 assigns identification information of the subjects W1-1 to W3-3 and corner identification information for identifying the corners of the subjects W1-1 to W3-3 to the four corners reconstructed by the reconstruction unit 52. The corner identification information is, for example, AD labels of the corners of the subjects W1-1 to W3-3 shown in FIG. 5. The information assigning unit 55 may assign the identification information and the corner identification information based on the positions where the imaging control unit 42 performed imaging. Alternatively, the information assigning unit 55 may distinguish the four corners included in the reconstructed image by image recognition processing, and assign the identification information and the corner identification information based on the image recognition processing.

[0073] In the above-described configuration, the information providing unit 55 provides the identification information and the corner specifying information, so that it is possible to identify which of the multiple inspected objects W has had a stacking misalignment detected, and to identify which corner of the inspected object the stacking misalignment detection result is related to. Therefore, it is possible to identify the inspected object and the corner where the stacking misalignment was detected.

[0074] The misalignment detection unit 56 detects stacking misalignment of the electrode plates at least at one of the four corner portions based on the tomographic image reconstructed by the reconstruction unit 52. The method of detecting stacking misalignment by the misalignment detection unit 56 will be described in detail later.

[0075] The above-described radiological inspection device 2 can efficiently obtain tomographic images of the ends where the corners of two rectangular parallelepiped test objects are located. Therefore, it is possible to provide a radiological inspection device 2 that can inspect multiple test objects W efficiently and accurately. Furthermore, the above-described radiological inspection device 2 can obtain tomographic images of a battery in which electrode plates are stacked. This can make battery inspection more efficient.

[0076] (Details of the shooting method by the shooting control unit) Fig. 7 is a plan view illustrating an imaging method performed by the imaging control unit 42. Referring to Fig. 7 in addition to Figs. 3 to 6, first, the imaging control unit 42 controls the moving mechanism 26 to move the radiation source 21 and the detector 22 to a position PS11 where the radiation source 21 can irradiate the corner C of the subject W1-1 and the corner A of the subject W2-1 with radiation obliquely. In Fig. 7, the positions of the radiation source 21 and the detector 22 are shown with reference to the rotation axis P1. Based on the projection data DP2 acquired by the imaging control unit 42 at the position PS11, the reconstruction unit 52 reconstructs a reconstruction image RP11.

[0077] Next, the imaging control unit 42 controls the moving mechanism 26 to move the radiation source 21 and the detector 22 in one direction in the Y-axis direction from position PS11 to position PS12. In plan view, position PS12 is located between four corners: corner D of subject W1-1, corner C of subject W1-2, corner B of subject W2-1, and corner A of subject W2-2. The radiation inspection apparatus 2 reconstructs a reconstructed image RP12 at position PS12.

[0078] Furthermore, the imaging control unit 42 controls the moving mechanism 26 to move the radiation source 21 and the detector 22 in one direction along the Y axis from position PS12 to position PS13, which is located between the next four corners. The radiation inspection apparatus 2 reconstructs a reconstructed image RP13 at position PS13.

[0079] Next, the imaging control unit 42 controls the moving mechanism 26 to move the radiation source 21 and the detector 22 from position PS13 to position PS14 in one direction in the Y-axis direction. The radiation inspection device 2 captures images of two corners, namely corner D of the subjects W1-3 and corner B of the subjects W2-3, at position PS14, which is located at one end in the Y-axis direction of the multiple subjects W arranged in a grid pattern, and reconstructs a reconstructed image RP14.

[0080] Next, the imaging control unit 42 controls the moving mechanism 26 to move the radiation source 21 and the detector 22 in one direction in the X-axis direction from position PS14 to position PS21. At position PS21, the radiation inspection apparatus 2 images two corners as imaging targets: corner D of the subject W2-3 and corner B of the subject W3-3, and reconstructs a reconstructed image RP21.

[0081] Thereafter, the radiological inspection device 2 moves the radiation source 21 and the detector 22 in the other direction of the Y-axis, symmetrically to the case from positions PS12 to PS14 described above, and reconstructs the reconstructed images RP22, RP23, and RP24 at positions PS22, PS23, and PS24, respectively.

[0082] In the above example, reconstructed images of four corners, A, B, C, and D, are acquired for each of the test objects W2-1, W2-2, and W2-3. The misalignment detection unit 56 detects stacking misalignment for each of the test objects W2-1, W2-2, and W2-3 for which reconstructed images of the four corners, A, B, C, and D, have been acquired. For example, reconstructed images RP11, RP12, RP23, and RP24 have been acquired for the test object W2-1. The misalignment detection unit 56 determines stacking misalignment for the four corners, A, B, C, and D, of the test object W2-1 based on the tomographic images of the reconstructed images RP11, RP12, RP23, and RP24. If no stacking misalignment is detected for all four corners, A, B, C, and D, of the test object W2-1, the misalignment detection unit 56 determines that the test object W2-1 is a non-defective product.

[0083] According to the above-described configuration, it is possible to detect stacking misalignment of the electrode plates of the battery 90 as the test object, thereby making it possible to efficiently inspect the stacking misalignment of the electrode plates of the battery 90.

[0084] (Details of how the misalignment detection unit detects stacking misalignment) Fig. 8 is a diagram illustrating an example of a method for detecting a lamination misalignment by the misalignment detection unit 56. Fig. 9 is a diagram illustrating another example of a method for detecting a lamination misalignment by the misalignment detection unit 56. Fig. 10 is a diagram illustrating yet another example of a method for detecting a lamination misalignment by the misalignment detection unit 56.

[0085] (1) With reference to FIG. 8 , an example of a method for detecting stack misalignment by the misalignment detection unit 56 will be described below. The misalignment detection unit 56 performs a Fourier transform on a tomographic image SE1 of the subject. Based on the result of the Fourier transform, the misalignment detection unit 56 calculates a power spectrum FT1 in the stacking direction at one end of the battery 90 in the X-axis direction. The position at which the power spectrum FT1 is calculated is, for example, a position at which only the negative electrode plate 93 is located among the positive electrode plate 92 and the negative electrode plate 93 in the stacking direction. Based on the result of the Fourier transform, the misalignment detection unit 56 calculates a power spectrum FT2 in the stacking direction at a position inward in the X-axis direction from one end of the battery 90. The position at which the power spectrum FT2 is calculated is, for example, a position at which the positive electrode plate 92 is located in the stacking direction.

[0086] Because the negative electrode plates 93 are stacked at a predetermined pitch in the stacking direction, a peak appears at a predetermined frequency in the frequency domain. The deviation detection unit 56 determines whether a peak appears in the power spectrum FT1 at the same frequency as a peak appears in the power spectrum FT2. If a peak does not appear in the power spectrum FT1 at the same frequency as a peak appears in the power spectrum FT2, it can be determined that the negative electrode plates 93 are not stacked at the predetermined pitch at one end of the battery 90 in the X-axis direction. In this case, for example, the end of the negative electrode plates 93 may not be aligned in the stacking direction, may be deformed, or may be missing. In this case, the deviation detection unit 56 determines that the battery 90 is defective.

[0087] (2) Referring to FIG. 9 , another example of a method for detecting stacking misalignment by the misalignment detection unit 56 will be described below. The misalignment detection unit 56 may detect stacking misalignment based on the degree of discrepancy between a portion SE12 located at one end of the battery 90 in the X-axis direction and a portion SE11 located inward in the X-axis direction from that end of the battery 90 in the tomographic image SE1 of the subject. The misalignment detection unit 56 calculates the degree of discrepancy based on, for example, a difference DF1 obtained by subtracting the portion SE12 from the portion SE11. The degree of discrepancy is, for example, the sum of pixel values included in the difference DF1. The greater the sum of pixel values, the higher the degree of discrepancy can be determined to be. If the degree of discrepancy is equal to or greater than a predetermined threshold, the misalignment detection unit 56 determines that the battery 90 is defective.

[0088] (3) Referring to FIG. 10 , another example of a method for detecting stacking misalignment by the misalignment detection unit 56 will be described below. The misalignment detection unit 56 generates tomographic images L1, . . . , Ln perpendicular to the stacking direction at the Z-axis position where the negative electrode plates 93, which are stacked at a predetermined pitch in the stacking direction, are located. That is, the tomographic images L1, . . . , Ln are obtained in cross sections parallel to the XY plane. The misalignment detection unit 56 determines whether the negative electrode plates 93 are located at the same position in each of the tomographic images L1, . . . , Ln. If the misalignment of the negative electrode plates 93 exceeds a predetermined threshold in each of the tomographic images L1, . . . , Ln, it can be determined that stacking misalignment has occurred in the negative electrode plates 93. The misalignment detection unit 56 may detect the stacking misalignment based on the degree of deviation described above. The deviation detection unit 56 determines that the battery 90 is defective when the deviation of the negative electrode plate 93 exceeds a predetermined threshold in each of the tomographic images L1, . . . , Ln.

[0089] [Embodiment 3] Fig. 11 is a functional block diagram showing a schematic configuration of a radiological inspection apparatus 3 according to embodiment 3. Fig. 12 is a side view showing a schematic configuration of the radiological inspection apparatus 3 according to embodiment 3. The radiological inspection apparatus 3 according to embodiment 3 differs from the radiological inspection apparatus 2 according to embodiment 2 in that the detector 221 has a plurality of detection areas 2211, 2212, 2221, and 2222. In the description of embodiment 3, detailed description of parts common to embodiment 2 will not be repeated.

[0090] (Overall composition) As shown in FIG. 11, the radiological inspection device 3 includes a radiation source 21, a detector 221, a support unit 231, a rotation drive mechanism 25, a movement mechanism 26, a memory unit 30, an imaging control unit 43, a reconstruction unit 53, an information providing unit 55, a deviation detection unit 56, an operation unit 61, and a display unit 62.

[0091] 4 again, the battery 90 as the subject includes a case 91, a positive electrode plate 92, and a negative electrode plate 93. The region of interest used for detecting stacking misalignment is the portion where the positive electrode plate 92 and the negative electrode plate 93 are stacked. Therefore, in the radiation inspection apparatus 3, as shown in FIG. 12, a region of interest ROI1 located inside the case of the subject WB and a region of interest ROI2 located inside the case of the subject WA are used for detecting stacking misalignment.

[0092] The detector 221 has four detection regions 2211 (first detection region), 2212 (third detection region), 2221 (second detection region), and 2222 (fourth detection region) that are aligned in a 2 x 2 grid pattern in the plan view. The four detection regions 2211, 2212, 2221, and 2222 are positioned on one side of the detector 221 at predetermined distances from each other.

[0093] The detection region 2211 is located on the other side of the 2×2 grid in the first horizontal direction and the other side of the second horizontal direction. The detection region 2211 detects radiation passing through a corner D of the first object.

[0094] The detection region 2212 is located on the other side of the 2×2 grid in the first horizontal direction and on one side of the second horizontal direction. The detection region 2212 detects radiation passing through a corner C of the third object.

[0095] The detection region 2221 is located at one end of the first horizontal direction and at the other end of the second horizontal direction in the 2×2 grid. The detection region 2221 detects radiation passing through a corner B of the second object.

[0096] The detection region 2222 is located on one side of the first horizontal direction and one side of the second horizontal direction in the 2×2 grid. The detection region 2222 detects radiation passing through a corner A of the fourth object.

[0097] 12, the detection regions 2211 and 2212 are located on one side of the first horizontal direction with respect to the optical axis Q1. A radiation passing region RG21 through which radiation emitted from the radiation source 21 passes and detected by the detection region 2211 or the detection region 2212 of the detector 221 overlaps with a part of the upper end and a part of the lower end of the region of interest ROI1 of the object WA.

[0098] The detection regions 2221 and 2222 are located on the other side of the first horizontal direction with respect to the optical axis Q1. A radiation passing region RG22, through which radiation irradiated from the radiation source 21 and detected by the detection region 2221 or the detection region 2222 of the detector 221 passes, overlaps with a part of the upper end and a part of the lower end of the region of interest ROI2 of the subject WB.

[0099] The imaging control unit 43 rotates the rotation drive mechanism 25 to rotate the radiation source 21, the detector 22, and the support unit 23 relative to one another around the rotation axis P1, and irradiates radiation from the radiation source 21 so that the radiation passes obliquely through the centers of the four 2×2 subjects in the planar view, and the radiation is detected by the detector 221.

[0100] The imaging control unit 43 acquires the projection data DP3 generated by the 2×2 grid-shaped detection areas 2211, 2212, 2221, and 2222 of the detector 221.

[0101] The reconstruction unit 53 reconstructs a tomographic image based on the projection data DP3.

[0102] In the above-described configuration, the four detection regions 2211, 2212, 2221, and 2222 are located at a predetermined distance from each other. Therefore, no radiation detection data is generated in positions between the four detection regions 2211, 2212, 2221, and 2222. This makes it possible to reduce the amount of projection data DP3. This reduces the calculation load on the reconstruction unit 53.

[0103] [Other embodiments] Although the embodiments of the present invention have been described above, the above-described embodiments are merely examples for carrying out the present invention. Therefore, the present invention is not limited to the above-described embodiments, and the above-described embodiments can be appropriately modified and carried out without departing from the spirit of the present invention.

[0104] In each of the above-described embodiments, the imaging control units 41, 42, and 43 of the radiological inspection apparatuses 1, 2, and 3 execute programs to realize various functions. That is, the imaging control unit 41 is realized by software. However, this is not limiting, and the control unit may be realized by hardware such as a dedicated integrated circuit. Furthermore, the program may be stored in a computer-readable storage medium that is capable of substantial storage rather than temporary storage. The storage medium may be part of the storage unit of the radiological inspection apparatus. Furthermore, the program may be supplied to the radiological inspection apparatus via any wired or wireless transmission medium.

[0105] In each of the above embodiments, the radiation source 21 includes a microfocus X-ray tube having a focal spot of several micrometers to several tens of micrometers. However, the radiation source may have a focal spot larger than the order of micrometers. The radiation source may also emit gamma rays, neutrons, or the like.

[0106] In each of the above-described embodiments, the Z-axis direction of the radiation inspection apparatuses 1, 2, and 3 is the vertical direction. However, the Z-axis direction of the radiation inspection apparatus may be the horizontal direction, or may be a direction different from the vertical and horizontal directions.

[0107] In each of the above embodiments, the rotation drive mechanism 25 drives the support parts 23, 231 to rotate about a rotation axis P1 extending in an axial direction perpendicular to the first horizontal direction relative to the radiation source 21 and the detectors 22, 221. However, the rotation axis may intersect with the first direction or the second direction in which the subject is aligned.

[0108] In each of the above embodiments, the support unit 23, 231 has a mounting surface on which the test object can be placed. However, the support unit may support the test object via a jig or the like. The test object may be fixedly attached to the support unit. There is no limitation on the method of supporting the test object relative to the mounting surface of the support unit. For example, the support unit may include a pallet that supports multiple test objects aligned in a grid pattern. Furthermore, when the detection of the misalignment is completed, the multiple test objects may be transported together with the pallet in the first horizontal direction, for example.

[0109] Although not specifically described in the above embodiments, the radiation source, detector, and support may each have a movement mechanism for moving in the X-axis direction, Y-axis direction, Z-axis direction, or the like.

[0110] In each of the above embodiments, the rotation drive mechanism 25, for example, drives the radiation source 21 and the detector 22, 221 to rotate in one direction about the rotation axis P1 relative to the support unit 23, 231. However, the rotation drive mechanism may also drive the support unit to rotate in one direction about the rotation axis relative to the radiation source and the detector. The rotation drive mechanism may also drive the support unit to rotate in the other direction about the rotation axis.

[0111] In each of the above-described embodiments, the radiation inspection apparatuses 1, 2, and 3 store the projection data DP1, DP2, and DP3 in the storage unit 30. However, the radiation inspection apparatuses may upload the projection data to an external server connected via a communication network.

[0112] In each of the above embodiments, the reconstruction units 51, 52, and 53 reconstruct multiple tomographic images of the subject W based on the projection data DP1, DP2, and DP3. However, the reconstruction units may perform reconstruction based on projection data that has been subjected to various correction processes. Furthermore, the imaging control unit may perform various corrections on the projection data during imaging.

[0113] In each of the above embodiments, when imaging multiple subjects W, the rotation drive mechanism 25 rotates the support part 23, 231 on which the multiple subjects W are placed by a predetermined angle or number of times under the control of the imaging control part 4142, 43. Although not specifically described in each of the above embodiments, the predetermined angle may be 360° or more. Also, the predetermined angle may be less than 360°. In other words, the predetermined number of rotations may be one rotation or more, or may be less than one rotation.

[0114] In the above-described embodiments, the detection areas 22a, 2211, 2212, 2221, and 2222 of the detectors 22 and 221 are parallel to the XY plane. However, for example, the detection areas of the detectors may be perpendicular to the optical axis.

[0115] Fig. 13 is a side view showing a schematic configuration of a radiological inspection apparatus 4 according to another embodiment. For example, as shown in Fig. 13, in the radiological inspection apparatus 4, the detection areas 2211, 2212, 2221, and 2222 of the detector 222 may be perpendicular to the optical axis Q1. The detection areas 2211, 2212, 2221, and 2222 are located on one surface of the detector 222. From another perspective, the one surface of the detector 222 is perpendicular to the optical axis Q1. Note that the distance of the detector 222 to the rotation axis P1 is, for example, based on the center of the detection areas 2211, 2212, 2221, and 2222.

[0116] Furthermore, in the radiation inspection apparatus 2 according to the second embodiment, the detection region 22a of the detector 22 may be perpendicular to the optical axis Q1. The detection region of the detector may be parallel to the ZY plane that extends vertically.

[0117] In the first embodiment, the radiation emitted from the radiation source 21 passes through a portion T1 of the first subject W1 and a portion T2 of the second subject W2. However, the radiation emitted from the radiation source may pass through at least a portion of the first subject and at least a portion of the second subject. For example, the radiation may pass through the entire first subject and the entire second subject.

[0118] In the second embodiment, the multiple subjects W are arranged in a grid of 3 rows and 3 columns. However, the multiple subjects W may be arranged in a grid of n rows and m columns, where n and m are natural numbers equal to or greater than 2.

[0119] In the second embodiment, the movement mechanism 26 moves the support part 231 in the first horizontal direction or the second horizontal direction. However, the movement mechanism may move at least one of the radiation source and detector and the support part in the first horizontal direction or the second horizontal direction. The movement mechanism may have, for example, a first movement unit that moves the radiation source and detector in the second horizontal direction and a second movement unit that moves the support part in the first horizontal direction.

[0120] In the second embodiment, the misalignment detection unit 56 detects stacking misalignment for the subjects W2-1, W2-2, and W2-3 for which reconstructed images of the four corner portions A, B, C, and D have been acquired. However, the radiological inspection apparatus may also acquire reconstructed images of the four corner portions of other subjects and detect stacking misalignment.

[0121] In the second embodiment, the radiation inspection apparatus 2 moves the radiation source 21 and the detector 22 in one direction in the Y-axis direction, and when the radiation source 21 and the detector 22 reach the other end in the Y-axis direction, moves the radiation source 21 and the detector 22 to adjacent imaging positions in the X-axis direction. However, the radiation inspection apparatus may also switch the direction in which the radiation source and the detector are moved between the X-axis direction and the Y-axis direction. [Industrial Applicability]

[0122] The present invention can be used in a radiation inspection apparatus and a tomographic image generating method for obtaining a tomographic image of a subject by irradiating the subject with radiation. [Explanation of symbols]

[0123] 1, 2, 3, 4 Radiation inspection equipment 21 Radiation source 22, 221, 222 detectors 22a, 2211, 2212, 2221, 2222 detection area 23, 231 Support part 23a, 231a Placement surface 25 Rotational drive mechanism 26 Moving mechanism 30 Storage section 41, 42, 43 Imaging control unit 51, 52, 53 Reconstruction part 55 Information provision section 56 Misalignment detection unit 61 Operation section 62 Display section 90 batteries 91 cases 92 Positive electrode plate 93, 931, 932 negative plates DP1, DP2, DP3 projection data L1, L2, ..., Ln, SE1 tomographic images P1 rotation axis Q1 Optical axis RG1 Radiation passing region ROI1, ROI2 Regions of Interest RP1, RP11, RP12, RP13, RP14, RP21, RP22, RP23, RP24 reconstructed images W Multiple subjects W1 1st subject W2 Second subject W1-1, W1-2, W1-3, W2-1, W2-2, W2-3, W3-1, W3-2, W3-3, WA, WB Subject

Claims

1. 1. A radiological inspection apparatus that generates a tomographic image based on projection data obtained by irradiating a subject with radiation, a radiation source that emits radiation in an optical axis direction; a detector having a detection area for the radiation irradiated by the radiation source; a support unit located between the radiation source and the detector, the support unit supporting a first subject and a second subject among the plurality of subjects in a state where the first subject and the second subject are aligned in a first direction intersecting with the optical axis direction; a rotation drive mechanism that rotates the support unit relative to the radiation source and the detector around a rotation axis that intersects with the first direction; an imaging control unit that irradiates the radiation from the radiation source while rotating the radiation source, the detector, and the support unit relatively about the rotation axis by the rotation drive mechanism so that the radiation passes through at least a portion of the first subject and at least a portion of the second subject, in a state where the first subject is located on one side of the first direction with respect to the rotation axis and the second subject is located on the other side of the first direction with respect to the rotation axis, and the optical axis direction intersects both the first direction and the rotation axis; and acquires projection data by the detector. a reconstruction unit that reconstructs a tomographic image of at least a part of each of the first object and the second object based on the projection data; having Radiation inspection equipment.

2. The radiological inspection apparatus according to claim 1, Each of the plurality of subjects has a rectangular parallelepiped shape, the first subject and the second subject are positioned side by side in the first direction, the imaging control unit irradiates the radiation from the radiation source so that the radiation passes through both the other end of the first subject in the first direction and the one end of the second subject in the first direction, and thereby acquires projection data with the detector. Radiation inspection equipment.

3. The radiological inspection apparatus according to claim 2, the first direction and the axial direction in which the rotation shaft extends are perpendicular to each other, the plurality of subjects are positioned so as to be aligned in the first direction and a second direction perpendicular to the axial direction and the first direction when viewed in the axial direction; Among the plurality of subjects, the first subject is located on one side of the second direction with respect to the rotation axis when viewed in the axial direction, the second object is located adjacent to the first object on the other side in the first direction when viewed in the axial direction, and is located on one side in the second direction with respect to the rotation axis; a third subject is located adjacent to the first subject on the other side in the second direction when viewed in the axial direction, and is located on the other side in the second direction with respect to the rotation axis; a fourth object is located adjacent to the second object on the other side in the second direction when viewed in the axial direction, and is located on the other side in the second direction with respect to the rotation axis; The imaging control unit a first corner portion located on the other side of the first object in the first direction and on the other side of the first object in the second direction; a second corner portion located on one side of the second object in the first direction and on the other side of the second object in the second direction; a third corner portion located on the other side of the third object in the first direction and on the one side of the third object in the second direction; a fourth corner portion located on one side of the fourth object in the first direction and on one side of the fourth object in the second direction; and acquiring projection data by the detector by irradiating the radiation from the radiation source so as to pass through four corner portions including the reconstruction unit reconstructs tomographic images of the four corner portions based on the projection data. Radiation inspection equipment.

4. The radiological inspection apparatus according to claim 3, the test object is a battery in which electrode plates are stacked with the axial direction as a stacking direction, Radiation inspection equipment.

5. The radiological inspection apparatus according to claim 4, The method further includes a displacement detection unit that detects a stacking displacement of the electrode plates at at least one of the four corner portions based on the tomographic image. Radiation inspection equipment.

6. The radiological inspection apparatus according to claim 5, an information assigning unit that assigns identification information of the object and corner specifying information for specifying the corners in the object to the four corners reconstructed by the reconstruction unit, the misalignment detection unit detects the stacking misalignment based on the identification information and the corner identification information. Radiation inspection equipment.

7. 7. The radiological inspection apparatus according to claim 3, the detector has a plurality of detection regions aligned in the first direction and the second direction and located on one side of the detector; The plurality of detection regions include: a first detection region that detects radiation passing through the first corner portion of the first object; a second detection region that detects radiation passing through the second corner portion of the second object; a third detection region that detects radiation passing through the third corner portion of the third object; a fourth detection region that detects radiation passing through the fourth corner portion of the fourth object; Including, Radiation inspection equipment.

8. a radiation source that emits radiation in an optical axis direction; a detector having a detection area for the radiation irradiated by the radiation source; a support portion positioned between the radiation source and the detector and configured to support a subject; a radiation source and a detector configured to rotate the support unit about a rotation axis intersecting the optical axis direction, and generate a tomographic image based on projection data obtained by irradiating the subject with radiation, the radiation source and the detector being configured to rotate the support unit about a rotation axis intersecting the optical axis direction, the radiation source and the detector being configured to rotate the support unit relative to the radiation source and the detector ... a supporting step of supporting a first object and a second object among the plurality of objects by the support unit while the first object and the second object are aligned in a first direction intersecting with the optical axis direction; a projection data acquisition step of irradiating the radiation from the radiation source with the detector while rotating the radiation source, the detector, and the support unit relatively about the rotation axis so that the radiation passes through at least a portion of the first object and at least a portion of the second object, with the first object positioned on one side of the first direction with respect to the rotation axis and the second object positioned on the other side of the first direction with respect to the rotation axis, and the optical axis direction intersecting both the first direction and the rotation axis; and a reconstruction step of reconstructing a tomographic image of at least a part of each of the first object and the second object based on the projection data; having A method for generating tomographic images.

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