Imaging system and imaging method

Abstract

To improve inspection accuracy.SOLUTION: The imaging system 1 includes an X-ray source 10 that irradiates a hollow sample S1 with X-rays R, an X-ray TDI camera 20 that images the X-rays R and performs a TDI operation, a rotation unit 30 that rotates the sample S1 relative to the X-ray source 10 and the X-ray TDI camera 20 to change an X-ray irradiated surface of the sample S1, and a control unit 50. The control unit 50 is configured to set the scan speed of the X-ray TDI camera 20, the rotation speed of the rotation unit 30, and the geometric magnification at the imaging position determined by the distance from the X-ray source 10 to the imaging position of the sample S1 and the distance from the X-ray source 10 to the X-ray TDI camera 20 so as to satisfy a predetermined relational expression.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an imaging system and an imaging method. [Background technology]

[0002] Patent Document 1 discloses an inspection device that inspects an item for the presence or absence of foreign matter by irradiating a moving object with radially spreading X-rays from an X-ray irradiation unit and detecting the X-rays that have passed through the object with an X-ray line sensor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-156635 Summary of the Invention [Problem to be solved by the invention]

[0004] When inspecting a hollow sample using the inspection device described above, if a foreign object such as a void is detected, it may be difficult to determine which of the two portions sandwiching the hollow portion the foreign object is located in. This may result in a decrease in inspection accuracy.

[0005] The present disclosure has been made in consideration of the above-described circumstances, and relates to an imaging system and an imaging method that can improve inspection accuracy. [Means for solving the problem]

[0006] (I) An imaging system according to one aspect of the present disclosure includes an X-ray source that irradiates a hollow sample with X-rays, an imaging element that performs a TDI (time delay integration) operation to capture an image of the X-rays that have passed through the sample, a rotation unit that changes the X-ray irradiation surface on the sample by rotating the sample relative to the X-ray source and the imaging element, and a control unit. The control unit is configured to set the scan speed of the imaging element, the rotation speed of the rotation unit, and the geometric magnification at the imaging position, which is determined by the distance from the X-ray source to the imaging position on the sample and the distance from the X-ray source to the imaging element, so as to satisfy the following formula (1): (Scan speed) = (Rotation speed) × (Geometric magnification at the imaging position) (1).

[0007] In an imaging system according to an embodiment of the present disclosure, the scan speed of the imaging device, the rotation speed of the rotating unit, and the geometric magnification at the imaging position are set to satisfy Equation (1) while the sample is rotated relative to the X-ray source and the imaging device. By performing various settings to satisfy Equation (1) in this manner, the scan speed of the imaging device and the rotation speed of the rotating unit can be synchronized while taking into account the geometric magnification, enabling high-precision imaging of a specific layer of the relatively rotating sample without image blurring. When a sample is hollow, it may be difficult to determine which portion of the sample is being imaged across the hollow. However, by performing various settings to satisfy Equation (1) as described above, when an image of a specific layer is generated, it is possible to appropriately determine which portion the imaged result is from (e.g., if a foreign object is detected, which portion the foreign object is located in). In other words, the imaging system according to an embodiment of the present disclosure can acquire images of a cross-sectional area with higher precision than a typical transmission image. From the above, the imaging system according to an embodiment of the present disclosure can improve inspection accuracy. Furthermore, in an imaging system according to one embodiment of the present disclosure, cross-sectional images similar to those obtained with X-ray CT can be obtained in a significantly shorter time than with X-ray CT, and therefore, the same determinations (examinations) as those using X-ray CT technology can be performed in a shorter time.

[0008] (II) In the imaging system described in (I) above, the control unit may be further configured to generate an image of a first layer corresponding to the imaging position based on the imaging result by the imaging element. With this configuration, it is possible to obtain a highly accurate tomographic image of the first layer corresponding to the predetermined imaging position.

[0009] (III) In the imaging system described in (I) or (II) above, the rotating unit may be a sample mounting unit that mounts a sample and rotates the sample. With this configuration, the tomographic image of the first layer can be easily acquired with a simple configuration in which only the sample is rotated.

[0010] (IV) In the imaging system described in (II) above, when the imaging position is changed to generate an image relating to a second layer different from the first layer, the control unit may change the scan speed according to the amount of change in the imaging position so as to satisfy formula (1). In this way, when the imaging position is changed to generate an image relating to the second layer different from the first layer, the scan speed is reset to satisfy formula (1) in accordance with the imaging position after the change, thereby making it possible to easily and appropriately acquire an image relating to the second layer.

[0011] (V) In the imaging system described in (II) above, when the imaging position is changed to generate an image relating to a second layer different from the first layer, the control unit may change the rotation speed according to the amount of change in the imaging position so as to satisfy formula (1). In this way, when the imaging position is changed to generate an image relating to the second layer different from the first layer, the rotation speed is reset to satisfy formula (1) in accordance with the imaging position after the change, thereby making it possible to easily and appropriately obtain an image relating to the second layer.

[0012] (VI) In the imaging system described in (III) above, the control unit may change the position of the rotation axis of the sample mounting unit so that the imaging position does not change when generating an image of a second layer different from the first layer. In this way, by changing the position of the rotation axis of the sample mounting unit when generating an image of the second layer different from the first layer, it is possible to easily and appropriately acquire an image of the second layer without changing the imaging position (i.e., without changing the condition related to formula (1) from when the image of the first layer was acquired).

[0013] (VII) In the imaging system described in any one of (I) to (VI) above, the control unit may set the scan speed, the rotation speed, and the geometric magnification at the imaging position so that the layer generating the captured image changes every time the sample rotates around one revolution, and equation (1) is satisfied. With this configuration, the condition of equation (1) is changed every time the sample rotates around one revolution, and different tomographic images can be appropriately acquired for each revolution.

[0014] (VIII) In the imaging system described in any one of (I) to (VII) above, the control unit may set the scan speed, the rotation speed, and the geometric magnification at the imaging position so that the layer generating the captured image changes continuously and always satisfies formula (1). With this configuration, it is possible to continuously change the condition of formula (1) and continuously change the layer to be imaged, thereby appropriately acquiring tomographic images.

[0015] (IX) An imaging method according to one aspect of the present disclosure is an imaging method performed using an imaging system having an X-ray source that irradiates a hollow sample with X-rays, an imaging element that performs a TDI (time delay integration) operation to image the X-rays that have passed through the sample, and a rotating unit that changes the X-ray irradiation surface on the sample by rotating the sample relative to the X-ray source and the imaging element, and includes setting the scan speed of the imaging element, the rotation speed of the rotating unit, and a geometric magnification at the imaging position, which is determined by the distance from the X-ray source to the imaging position on the sample and the distance from the X-ray source to the imaging element, so as to satisfy the following formula (1): (Scan speed) = (Rotation speed) × (Geometric magnification at the imaging position) (1) Imaging method. [Effects of the Invention]

[0016] According to the present disclosure, inspection accuracy can be improved. [Brief explanation of the drawings]

[0017] [Figure 1]FIG. 1 is a plan view schematically showing an imaging system according to an embodiment. [Figure 2] FIG. 2 is a development of a tomographic image. [Figure 3] FIG. 3 is a diagram for explaining a change of the fault extraction position. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, the embodiments will be described in detail with reference to the drawings. In each drawing, the same or corresponding parts are designated by the same reference numerals, and duplicated explanations will be omitted.

[0019] FIG. 1 is a plan view schematically illustrating an imaging system 1 according to an embodiment. The imaging system 1 is a system that performs X-ray nondestructive inspection of a sample. The imaging system 1 inspects the sample, for example, by detecting minute foreign matter (e.g., voids) in the sample. Note that in this embodiment, the imaging system 1 is described as detecting minute foreign matter in the sample, but application examples of the inspection system according to the present disclosure are not limited to this. The imaging system according to the present disclosure may be one that performs X-ray nondestructive inspection by irradiating X-rays on a sample, and may be one that performs various types of inspection, such as checking for the presence of various foreign matter, defective sealing, or missing parts. Furthermore, the imaging system according to the present disclosure may be used for purposes other than inspection, such as synthesizing tomographic images to construct a three-dimensional image and analyzing internal structures.

[0020] The imaging system 1 includes an X-ray source 10, an X-ray TDI (time delay integration) camera 20 (imaging element), a rotating unit 30, and a control unit 50.

[0021] The X-ray source 10 irradiates the hollow cylindrical sample S1 with X-rays R. Specifically, the X-ray source 10 irradiates the side peripheral surface of the sample S1 with X-rays R. The sample S1 is a hollow cylindrical part, for example, about 500 mm in diameter, and is a molded product to be inspected, which may have voids inside the side wall. Note that the sample S1 may be an object other than the molded product described above, as long as it is a hollow cylindrical object to be inspected. The sample S1 is rotatably supported by a rotating unit 30 (details will be described later).

[0022] The X-ray source 10 may be, for example, a microfocus X-ray source. The microfocus X-ray source is an X-ray source with a focal radius of, for example, 10 μm or less (e.g., 5 μm or less), and can generate a clear shadow even for minute foreign matter in the sample S1 irradiated with X-rays. In this way, by using a small focal point (microfocus), the X-ray source 10 obtains a clear projection image with little blurring.

[0023] The X-ray TDI camera 20 is an imaging element that performs TDI operation to capture X-rays R transmitted through the sample S1. The X-ray TDI camera 20 is disposed at a position sandwiching the sample S1 between itself and the X-ray source 10. The X-ray TDI camera 20 may have, for example, a CCD (Charge-Coupled Device) as its imaging element. A CCD performs vertical transfer on a line-by-line basis when reading out electric charges. By synchronizing the timing of this transfer (scan speed) with the rotation speed of the sample S1 (described later), integrated exposure can be performed for the number of vertical stages of the CCD. This method is called TDI, and it can capture images of the moving (rotating) sample S1 at high speed and with high sensitivity. Note that the X-ray TDI camera 20 is not limited to a CCD, and any other device capable of the above-described TDI operation can be used. That is, it may include an imaging element other than a CCD (for example, a CMOS (Complementary Metal Oxide Semiconductor)), or it may be one that performs pseudo-TDI operation on a circuit of multiple pixels connected by wiring, or it may be one that performs TDI addition on a memory of signals from multiple pixels.It may also be a TDI camera that uses an X-ray direct conversion semiconductor element (for example, a Cd-Te element).

[0024] The rotation unit 30 rotates the sample S1 relative to the X-ray source 10 and the X-ray TDI camera 20, thereby changing the irradiation surface of the sample S1 with the X-rays R. In this embodiment, the rotation unit 30 is a sample mounting unit that mounts the sample S1 and rotates the sample S1. The rotation unit 30 is located between the X-ray source 10 and the X-ray TDI camera 20, and mounts the lower surface of the hollow cylindrical sample S1. The rotation unit 30 rotates the mounted sample S1 at a rotation speed set by the control unit 50. The rotation unit 30 rotates the sample S1 while fixing the position of the rotation axis Ax of the sample S1, thereby continuously changing the irradiation surface of the X-rays R on the circumferential surface of the sample S1. The rotation axis Ax of the sample S1 and Ax can be rephrased as the rotation axis Ax of the rotation unit 30.

[0025] In this embodiment, the rotating unit 30 is described as placing and rotating the sample S1, but as described above, the rotating unit may be any unit that rotates the sample S1 relative to the X-ray source 10 and the X-ray TDI camera 20, and may therefore be a unit that supports the rotation of the X-ray source 10 and the X-ray TDI camera 20 so that the X-ray source 10 and the X-ray TDI camera 20 rotate around the sample S1 while the sample S1 is stationary.

[0026] The control unit 50 controls the operation of each component included in the imaging system 1. The control unit 50 is configured to execute a setting process for making various settings and an image generation process for generating a captured image.

[0027] The setting process is a process of setting the scan speed, rotation speed, and geometric magnification at the imaging position so that a tomographic image (captured image) of a desired layer in the sample S1 is appropriately acquired. The scan speed is the scan speed of the X-ray TDI camera 20. The rotation speed is the rotation speed of the rotating unit 30 (i.e., the rotation speed of the sample S1). The geometric magnification at the imaging position is the geometric magnification at the imaging position determined by the distance from the X-ray emission position of the X-ray source 10 to the imaging position in the sample S1 (the position where a tomographic image is desired to be acquired) and the distance from the X-ray emission position of the X-ray source 10 to the X-ray TDI camera 20 (details will be described later).

[0028] In the setting process, the control unit 50 sets the scan speed of the X-ray TDI camera 20, the rotation speed of the rotating unit 30, and the geometric magnification at the imaging position so as to satisfy the following formula (1). (Scan speed) = (Rotation speed) × (Geometric magnification at the imaging position) (1)

[0029] As described above, the geometric magnification at the imaging position is determined by the distance from the X-ray emission position of the X-ray source 10 to the imaging position in the sample S1 (the position where a tomographic image is to be acquired) and the distance from the X-ray emission position of the X-ray source 10 to the X-ray TDI camera 20. Now, let us assume that the distance from the X-ray emission position of the X-ray source 10 to the imaging position in the sample S1 (the position where a tomographic image is to be acquired) is FOD (Focus to Object Distance), and the distance from the X-ray emission position of the X-ray source 10 to the X-ray TDI camera 20 is FDD (Focus to Detector Distance). The geometric magnification is determined by FDD / FOD.

[0030] For example, as shown in Figure 1, if the distance to the imaging position relatively close to the X-ray source 10 is FOD A = 100 mm, and the distance to the imaging position relatively far from the X-ray source 10 is FOD B = 600 mm, and FDD = 1000 mm, then the geometric magnification when the imaging position is close to the X-ray source 10 is 1000 mm / 100 mm = 10 times, and the geometric magnification when the imaging position is far from the X-ray source 10 is 1000 mm / 600 mm = approximately 1.6 times. Increasing the geometric magnification allows for a higher resolution image to be obtained, but the imaging range becomes narrower.

[0031] The geometric magnification may be determined, for example, according to the following flow. First, the size of the defect (void) to be detected is determined, and the required spatial resolution is determined accordingly. Next, the pixel size of the X-ray TDI camera 20 is confirmed. Then, the required geometric magnification is calculated using the following equation (2). In the example of the following equation (2), the required spatial resolution is set to five times the defect size. (Required geometric magnification) = (detector pixel size) ÷ (defect size to be detected ÷ 5) (2)

[0032] According to the above formula (2), for example, if you want to detect a 50 μm foreign particle on a sample using a detector (X-ray TDI camera 20) with a pixel size of 100 μm, the required geometric magnification is calculated as 100 μm ÷ (50 μm ÷ 5) = 10 times.

[0033] According to equation (1), for example, when the rotation speed is 10 mm / s and the geometric magnification of the imaging position (FOD A = 100 mm) relatively close to the X-ray source 10 is 10x, the scan speed is calculated as 10 × 10 = 100 mm / s. As shown in FIG. 1, the imaging position (FOD A = 100 mm) relatively close to the X-ray source 10 is the imaging position where void V1 can be imaged, and the imaging position (FOD B = 600 mm) relatively far from the X-ray source 10 is the imaging position where void V2 can be imaged. In this case, if the scan speed for imaging void V1 is set to 100 mm / s, void V2 will be difficult to image due to synchronization issues. Furthermore, assuming that the sample S1 rotates clockwise as shown in FIG. 1, the scan direction of the X-ray TDI camera 20 to inspect the position of void V1 is set to the same direction as the movement direction of void V1 (upward in the figure). In this case, the void V2 moves in the opposite direction (downward in the drawing) to the scanning direction of the X-ray TDI camera 20, making it even more difficult for the void V2 to appear in the image.

[0034] The image generation process is a process for generating a tomographic image (captured image) based on the imaging results of the X-ray TDI camera 20. The control unit 50 generates a tomographic image (captured image) of the layer (first layer) corresponding to the imaging position based on the imaging results of the X-ray TDI camera 20. FIG. 2 shows a development IM of the tomographic image. For example, assume that various conditions are set so that the void V1 can be imaged at the imaging position (FOD A = 100 mm) relatively close to the X-ray source 10. Then, the sample S1 rotates once, and a tomographic image of the first layer 101 (see FIG. 1) is acquired, thereby obtaining a development IM of the cross section (tomographic image) as shown in FIG. 2. In the example shown in FIG. 1, voids V1 and V2 are located exactly on the first layer 101, so that the voids V1 and V2 are displayed in the development IM of the cross section as shown in FIG. 2. In this way, by generating a tomographic image while rotating the sample S1, it is possible to image voids in a predetermined cross section in a short period of time without performing CT imaging. In the above description, various conditions are set to capture the image of void V1 (synchronized with void V1) during tomographic image acquisition. However, if the void size is relatively large (for example, if the void is sufficiently large, such as five times or more the pixel size of the detector), the tomographic image may be acquired in synchronization with the position of void V2. As shown in equation (1) above, if the geometric magnification is reduced by synchronizing with the position of void V2, the scan speed will be slower even at the same rotation speed. This has the advantageous effects of brightening the image, improving the image S / N ratio, and widening the detection width (the range that can be inspected in one image capture).

[0035] The control unit 50 may change and set various conditions in order to generate an image relating to a second layer different from the first layer (to change the fault extraction position). FIG. 3 is a diagram illustrating the change of the fault extraction position. As shown in FIG. 3, an example will be described in which the fault extraction position is changed from the first layer 101 to the second layer 102. Now, assume that the imaging position when imaging the first layer 101 is FOD A=100 mm, and the imaging position when imaging the second layer 102 is FOD A'=90 mm.

[0036] When changing the imaging position to generate a tomographic image of the second layer 102 different from the first layer 101, the control unit 50 may change the scan speed according to the amount of change in the imaging position so as to satisfy the above formula (1). Assume now that the scan speed when acquiring a tomographic image of the first layer 101 is [rotation speed (10 mm / s)] × [geometric magnification (10x) at imaging position (FOD A = 100 mm)] = 100 mm / s. When imaging the second layer 102, the imaging position is FOD A' = 90 mm, so the geometric magnification becomes 1000 ÷ 90x. Since the geometric magnification changes from 10x to 1000 ÷ 90x in this way, the control unit 50 changes the scan speed according to the change in geometric magnification so as to satisfy the formula (1). Specifically, the control unit 50 derives [rotation speed (10 mm / s)] × [geometric magnification (1000 ÷ 90 times) at the imaging position (FOD A' = 90 mm)] ≈ 11 mm / s as the scan speed for generating a tomographic image of the second layer 102. According to this method of changing the scan speed, the tomographic extraction position can be easily and quickly changed by simply changing the setting of the scan speed of the X-ray TDI camera 20, without making any physical changes such as changing the rotation speed of the sample S1.

[0037] When changing the imaging position to generate a tomographic image of the second layer 102 different from the first layer 101, the control unit 50 may change the rotation speed of the sample S1 in accordance with the amount of change in the imaging position so as to satisfy the above formula (1). Assume now that the rotation speed when acquiring a tomographic image of the first layer 101 is [scan speed (100 mm / s)] ÷ [geometric magnification (10x) at imaging position (FOD A = 100 mm)] = 10 mm / s. When imaging the second layer 102, the imaging position is FOD A' = 90 mm, so the geometric magnification becomes 1000 ÷ 90x. Since the geometric magnification changes from 10x to 1000 ÷ 90x in this way, the control unit 50 changes the rotation speed in accordance with the change in the geometric magnification so as to satisfy the formula (1). Specifically, the control unit 50 derives [scan speed (100 mm / s)] ÷ [geometric magnification (1000 ÷ 90x) at imaging position (FOD A' = 90 mm)] = 9 mm / s as the rotation speed for generating a tomographic image of the second layer 102. According to this method of changing the rotation speed of the sample S1, the rotation speed can be arbitrarily changed for each rotation, for example, 10 mm / s for the first rotation, 9 mm / s for the second rotation, etc., and tomographic images corresponding to the change can be continuously obtained in a short period of time.

[0038] When generating a tomographic image of the second layer 102, which is different from the first layer 101, the control unit 50 may control the rotation unit 30 to change the position of the rotation axis Ax of the rotation unit 30 on which the sample S1 is placed and rotated so that the imaging position does not change. As described above, when the position of the rotation axis Ax is not changed, the imaging position when imaging the first layer 101 is assumed to be FOD A=100 mm, and the imaging position when imaging the second layer 102 is assumed to be FOD A′=90 mm. In this case, if the position of the rotation axis Ax is changed so that the imaging position when imaging the second layer 102 is FOD A′=100 mm, the imaging position does not change when imaging the first layer 101 and the second layer 102, so it is not necessary to change the conditions to satisfy equation (1). The control unit 50 may output a control signal to the rotation unit 30 so that the position of the rotation axis Ax is changed so that the imaging position when imaging the second layer 102 is FOD A′=100 mm. The control signal is a signal that instructs the rotation axis Ax to move 10 mm toward the X-ray TDI camera 20. The rotating unit 30 may slide in response to the control signal so that the position of the rotation axis Ax moves 10 mm toward the X-ray TDI camera 20. According to this method of changing the position of the rotation axis Ax, the position of the rotation axis Ax can be arbitrarily changed for each rotation, for example, at the initial position for the first rotation and moved 10 mm toward the X-ray TDI camera 20 for the second rotation, and tomographic images corresponding to the change can be continuously obtained in a short period of time.

[0039] When generating tomographic images (captured images) of multiple layers, the control unit 50 may change the tomographic extraction position at any timing. For example, the control unit 50 may set the scan speed, rotation speed, and geometric magnification at the imaging position so that the layer for generating a tomographic image changes every time the sample S1 rotates once, and the above formula (1) is satisfied. Furthermore, the control unit 50 may set the scan speed, rotation speed, and geometric magnification at the imaging position so that the layer for generating a tomographic image changes continuously (always) and always satisfies the above formula (1).

[0040] Next, the effects of the imaging system 1 according to this embodiment will be described.

[0041] The imaging system 1 includes an X-ray source 10 that irradiates a hollow sample S1 with X-rays R, an X-ray TDI camera 20 that performs TDI operation to image the X-rays R that have passed through the sample S1, a rotation unit 30 that changes the X-ray irradiation surface on the sample S1 by rotating the sample S1 relatively to the X-ray source 10 and the X-ray TDI camera 20, and a control unit 50. The control unit 50 sets the scan speed of the X-ray TDI camera 20, the rotation speed of the rotation unit 30, and the geometric magnification at the imaging position, which is determined by the distance from the X-ray source 10 to the imaging position on the sample S1 and the distance from the X-ray source 10 to the X-ray TDI camera 20, so as to satisfy the following formula (1): (Scan speed) = (Rotation speed) × (Geometric magnification at the imaging position) (1) and generating an image of the first layer corresponding to the imaging position based on the imaging result by the X-ray TDI camera 20.

[0042] In the imaging system 1 according to the present embodiment, the sample S1 is rotated relative to the X-ray source 10 and the X-ray TDI camera 20, and the scan speed of the X-ray TDI camera 20, the rotation speed of the rotating unit 30, and the geometric magnification at the imaging position are set to satisfy Equation (1). By performing various settings to satisfy Equation (1) in this manner, the scan speed of the X-ray TDI camera 20 and the rotation speed of the rotating unit 30 can be synchronized while taking into account the geometric magnification, enabling high-precision imaging of a predetermined layer (here, the first layer) of the relatively rotating sample S1 without image blurring. If the sample S1 is hollow, it may be difficult to determine which portion of the sample S1 is imaged across the cavity. However, by performing various settings to satisfy Equation (1) as described above and generating an image of the first layer corresponding to the predetermined imaging position, it is possible to appropriately determine which portion the imaged result is from (for example, if a void is detected, which portion the void is located in). That is, the imaging system 1 according to this embodiment can acquire images of a tomographic section with higher accuracy than a general transmission image. As described above, the imaging system 1 according to this embodiment can improve the inspection accuracy. Furthermore, the imaging system 1 according to this embodiment can acquire tomographic images similar to those obtained with X-ray CT in a significantly shorter time than with X-ray CT, and therefore can perform the same judgment (inspection) as when X-ray CT technology is used in a short time.

[0043] The rotating unit 30 may be a sample mounting unit that mounts the sample S1 and rotates the sample S1. With such a configuration, the tomographic image of the first layer can be easily acquired with a simple configuration in which only the sample S1 is rotated.

[0044] When changing the imaging position to generate a captured image of a second layer different from the first layer, the control unit 50 may change the scan speed according to the amount of change in the imaging position so as to satisfy formula (1). In this way, when changing the imaging position to generate a captured image of the second layer different from the first layer, the scan speed is reset to satisfy formula (1) in accordance with the imaging position after the change, thereby making it possible to easily and appropriately acquire a captured image of the second layer.

[0045] When changing the imaging position to generate a captured image of a second layer different from the first layer, the control unit 50 may change the rotation speed according to the amount of change in the imaging position so as to satisfy formula (1). In this way, when changing the imaging position to generate a captured image of the second layer different from the first layer, the rotation speed is reset to satisfy formula (1) in accordance with the imaging position after the change, thereby making it possible to easily and appropriately acquire a captured image of the second layer.

[0046] When generating a captured image relating to a second layer different from the first layer, the control unit 50 may change the position of the rotation axis Ax of the rotating unit 30 so that the imaging position does not change. In this way, by changing the position of the rotation axis Ax when generating a captured image relating to the second layer different from the first layer, it is possible to easily and appropriately acquire a captured image relating to the second layer without changing the imaging position (i.e., without changing the condition relating to equation (1) from when the captured image relating to the first layer was acquired).

[0047] The control unit 50 may set the scan speed, rotation speed, and geometric magnification at the imaging position so that the layer generating the captured image changes each time the sample S1 rotates around one revolution, and equation (1) is satisfied. With this configuration, the condition of equation (1) is changed each time the sample S1 rotates around one revolution, and different tomographic images can be appropriately acquired for each revolution.

[0048] The control unit 50 may set the scan speed, rotation speed, and geometric magnification at the imaging position so that the layer from which the captured image is generated changes continuously and always satisfies equation (1). With this configuration, it is possible to continuously change the condition of equation (1) and continuously change the layer to be imaged, thereby appropriately acquiring tomographic images. [Explanation of symbols]

[0049] 1...imaging system, 10...X-ray source, 20...X-ray TDI camera, 30...rotating unit, 50...control unit, S1...sample.

Claims

1. an X-ray source that irradiates a hollow sample with X-rays; an imaging element that performs a time delay integration (TDI) operation to image the X-rays that have passed through the sample; a rotation unit that rotates the sample relative to the X-ray source and the imaging element to change the irradiation surface of the X-ray on the sample; a control unit, The control unit and setting a scan speed of the imaging element, a rotation speed of the rotating unit, and a geometric magnification at the imaging position, which is determined by a distance from the X-ray source to an imaging position on the sample and a distance from the X-ray source to the imaging element, so as to satisfy the following formula (1): (Scan speed)=(Rotation speed)×(Geometric magnification at imaging position) (1) Imaging system.

2. The control unit The imaging system according to claim 1 , further configured to generate an imaged image of a first layer corresponding to the imaging position based on an imaging result by the imaging element.

3. The imaging system according to claim 2 , wherein the rotating section is a sample mounting section for mounting the sample and rotating the sample.

4. The control unit 3. The imaging system of claim 2, wherein when the imaging position is changed to generate an image of a second layer different from the first layer, the scan speed is changed according to the amount of change in the imaging position so as to satisfy equation (1).

5. The control unit 3. The imaging system according to claim 2, wherein, when the imaging position is changed to generate an image relating to a second layer different from the first layer, the rotation speed is changed according to an amount of change in the imaging position so as to satisfy the formula (1).

6. The control unit 4. The imaging system according to claim 3, wherein when generating a captured image of a second layer different from the first layer, the position of the rotation axis of the sample placement unit is changed so that the imaging position does not change.

7. The control unit 2. The imaging system according to claim 1, wherein the scan speed, the rotation speed, and the geometric magnification at the imaging position are set so as to satisfy the formula (1) after the layer generating the image changes every time the sample rotates once.

8. The control unit 2. The imaging system according to claim 1, wherein the scan speed, the rotation speed, and the geometric magnification at the imaging position are set so that a layer generating an image changes continuously and always satisfies the formula (1).

9. An imaging method using an imaging system including an X-ray source that irradiates a hollow sample with X-rays, an imaging element that performs a time delay integration (TDI) operation to image the X-rays that have passed through the sample, and a rotation unit that changes an irradiation surface of the X-rays on the sample by rotating the sample relatively to the X-ray source and the imaging element, setting a scan speed of the imaging element, a rotation speed of the rotating unit, and a geometric magnification at the imaging position, which is determined by a distance from the X-ray source to an imaging position on the sample and a distance from the X-ray source to the imaging element, so as to satisfy the following formula (1): (Scan speed)=(Rotation speed)×(Geometric magnification at imaging position) (1) Imaging method.

Images