X-ray inspection device

Abstract

To provide an X-ray inspection device capable of selecting an optimum metal filter even when a user is unaware of the material quality of the object to be inspected.SOLUTION: An X-ray inspection device 100 comprises: a radiation source 2 for irradiating an inspection object A with an X-ray; a detector 3 located facing the radiation source across the inspection object A; a metal filter unit 4 located between the inspection object A and the radiation source 2; a storage unit 74 for storing a threshold that represents a boundary of pixel values corresponding to the material quality of the inspection object A; a pixel value calculation unit 73 for calculating the pixel value of the inspection object A from the result of imaging; a material quality determination unit 75 for comparing the pixel value of the inspection object A with thresholds Th1, Th2 and determining the material quality of the inspection object A; and a metal filter selection unit 76 for selecting a metal filter unit 4 corresponding to the material quality of the inspection object A, on the basis of determination results from the material quality determination unit 75. The storage unit 74 stores a metal filter unit 4 most suitable for the material quality of the inspection object A in correspondence to each other.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] An embodiment of the present invention relates to an X-ray inspection apparatus. [Background technology]

[0002] Industrial X-ray inspection equipment is widely used to inspect small electronic components such as lithium-ion batteries with high resolution. In this X-ray inspection equipment, a radiation source that irradiates radiation, such as an X-ray beam, and a detector that detects the X-ray beam from the radiation source with two-dimensional resolution are arranged facing each other. A rotatable inspection table is provided between the radiation source and the detector. While the X-ray beam is irradiating the object to be inspected placed on the inspection table, the inspection table rotates once, irradiating the X-ray beam in all directions of the object to create a CT image or a fluoroscopic image.

[0003] When an object to be inspected is photographed using an X-ray inspection device, artifacts may occur. An artifact is a so-called noise, and is a phenomenon in which false images such as black or white streaks occur in the captured image when a substance with a large attenuation coefficient, such as a metal, is present. When artifacts occur, the image becomes unclear, which may make inspection difficult. Therefore, in order to suppress the occurrence of such artifacts, it is known to provide a metal filter between the radiation source and the object to be inspected.

[0004] When an object is imaged using a CT scanner, metal artifacts may occur. Metal artifacts are a phenomenon in which false images such as black or white streaks appear in the captured image when a substance with a large attenuation coefficient, such as metal, is present. Metal artifacts cause the image to become unclear, making the examination difficult and problematic. To prevent metal artifacts from occurring, it is known to place a thin, plate-shaped metal filter made of copper or other material between the radiation source and the object being examined. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2005-062200 A Summary of the Invention [Problem to be solved by the invention]

[0006] The metal filter is a metal plate made of copper, aluminum, iron, or an alloy containing these materials. The metal plates constituting the metal filter are available in a variety of different thicknesses. Thus, metal filters are available in a variety of materials and thicknesses.

[0007] By selecting the optimum metal filter according to the material of the object to be inspected, the occurrence of artifacts can be effectively suppressed. However, for an inexperienced user, selecting the optimum metal filter is a difficult task in the first place, and there are also cases where the material of the object to be inspected is unknown, making it a difficult task even for an experienced user.

[0008] An embodiment of the present invention has been made to solve the above-mentioned problems, and its purpose is to provide an X-ray inspection device that allows a user to select an optimal metal filter even if the user does not know the material of the object to be inspected. [Means for solving the problem]

[0009] An X-ray inspection apparatus in an embodiment of the present invention comprises a radiation source which irradiates an object under inspection with X-rays, a detector which is arranged facing the radiation source across the object under inspection, a metal filter unit which is arranged between the object under inspection and the radiation source, a memory unit which stores a threshold value which is a boundary between pixel values ​​according to the material of the object under inspection, a pixel value calculation unit which calculates the pixel value of the object under inspection from the shooting results, a material determination unit which compares the threshold value with the pixel value of the object under inspection to determine the material of the object under inspection, and a metal filter selection unit which selects the metal filter unit which corresponds to the material of the object under inspection based on the determination result of the material determination unit, and the memory unit stores the metal filter unit which is optimal for the material of the object under inspection in correspondence with the material. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a side view that illustrates a schematic diagram of an X-ray inspection apparatus according to a first embodiment. [Diagram 2] FIG. 1 is a top view that illustrates typically an X-ray inspection apparatus according to a first embodiment. [Diagram 3] FIG. 2 is a block diagram showing the configuration of a control unit in the first embodiment. [Figure 4] 13 is a diagram showing an example of a histogram created by a pixel value calculation unit; FIG. [Diagram 5] 11 is a diagram showing the correspondence relationship between the material of the object to be inspected, a threshold value, and the type of metal filter portion. FIG. [Figure 6] 13 is a diagram showing the correspondence between the material of the object to be inspected, the image quality selected by the user, and the metal filter portion. FIG. [Figure 7] 11 is a flowchart relating to determination of the material of an object to be inspected and selection of a metal filter portion. [Figure 8] FIG. 11 is a side view that illustrates a schematic view of an X-ray inspection apparatus according to a second embodiment. [Figure 9] FIG. 11 is a top view that illustrates typically an X-ray inspection apparatus according to a second embodiment. [Figure 10] FIG. 11 is a block diagram showing the configuration of a control unit in a second embodiment. [Figure 11] FIG. 2 is a top view showing the optimal FCD state. [Figure 12] FIG. 2 is a schematic side view of an X-ray inspection device showing various parameters required for a scan number calculation unit to calculate the number of shots. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] (First embodiment) Hereinafter, an X-ray inspection apparatus according to a first embodiment will be described in detail with reference to the drawings. Fig. 1 is a side view that shows the X-ray inspection apparatus according to the first embodiment. Fig. 2 is a top view that shows the X-ray inspection apparatus according to the first embodiment.

[0012] The X-ray inspection apparatus 100 is an apparatus used for non-destructive inspection of an object to be inspected A. The X-ray inspection apparatus 100 irradiates the periphery of the object to be inspected A with a radiation beam that penetrates the object to be inspected A, and detects the amount of radiation attenuated by passing through the object to be inspected A. Then, based on the detection result, a CT image, which is a cross-sectional image of the object to be inspected A, is generated. The X-ray inspection apparatus 100 also generates a 3D image from the multiple CT images generated.

[0013] As shown in Fig. 1, the X-ray inspection apparatus 100 comprises an inspection table 1, a radiation source 2, a detector 3, a metal filter unit 4, a display unit 5, an input unit 6, and a control unit 7. The inspection table 1 is a table having a mounting surface on which an object A to be inspected is placed. The inspection table 1 is movable in a direction parallel to the mounting surface or in a direction perpendicular to the mounting surface. The inspection table 1 is also rotatable around an axis perpendicular to the mounting surface. The inspection table 1 has a sample table 11, a rotation / elevation mechanism 12, a Y-shift mechanism 13, and an X-shift mechanism 14.

[0014] The specimen A is placed on the specimen table 11. The surface of the specimen table 11 for placing the specimen A is flat. The position of the specimen table 11 is adjusted by a rotation / elevation mechanism 12, a Y-shift mechanism 13, and an X-shift mechanism .

[0015] The rotation and elevation mechanism 12 is provided below the sample table 11. The rotation and elevation mechanism 12 is configured, for example, by an actuator including a drive source such as a motor, and is provided rotatable about an axis perpendicular to the placement surface. The rotation and elevation mechanism 12 rotates the sample table 11, and the object A to be inspected is irradiated with the radiation beam in all directions.

[0016] In addition, the rotation / lifting mechanism 12 can move in a direction perpendicular to the mounting surface, for example, by using a ball screw mechanism driven by a servo motor. That is, the height of the mounting surface can be adjusted by moving the rotation / lifting mechanism 12 in a direction perpendicular to the mounting surface.

[0017] The Y-shift mechanism 13 is provided below the rotation / elevation mechanism 12. The Y-shift mechanism 13 moves the sample table 11 in a direction parallel to the mounting surface and perpendicular to the optical axis of the radiation beam. The X-shift mechanism 14 is provided below the Y-shift mechanism 13. The X-shift mechanism 14 moves the sample table 11 in a direction parallel to the optical axis of the radiation beam. The Y-shift mechanism 13 and the X-shift mechanism 14 can be, for example, a ball screw mechanism driven by a servo motor.

[0018] The radiation source 2 irradiates, for example, a radiation beam that penetrates the inspection object A. The radiation beam is a bundle of radiation rays that spreads in a cone shape with a fan angle and a cone angle, with the apex being the focal point F of the radiation source. In this embodiment, the radiation source 2 is, for example, a reflective or transmissive microfocus X-ray tube or nanofocus X-ray tube, and the radiation beam is an X-ray beam.

[0019] The detector 3 is provided facing the radiation source 2 across the inspection table 1 and the object to be inspected A. The detector 3 is provided so that the center of the imaging area coincides with the optical axis of the radiation source 2. The detector 3 detects a two-dimensional distribution of radiation intensity attenuated according to the transmission path of the radiation beam, and outputs a fluoroscopic image. The detector 3 is formed of, for example, a flat panel detector (FPD).

[0020] The detector 3 has a movement mechanism that adjusts the distance from the object A to be inspected. The detector 3 can be moved by the movement mechanism in a direction perpendicular to the imaging area (parallel to the optical axis of the radiation source 2). Note that the detector 3 can also be moved by the movement mechanism in a direction parallel to the imaging area in order to align the optical axis of the radiation source with the center of the imaging area.

[0021] The metal filter unit 4 is disposed between the object to be inspected A and the radiation source 2, in the vicinity of the radiation source 2. The metal filter unit 4 is a thin plate member having a thickness of about several mm. The metal filter unit 4 is a metal plate made of copper, aluminum, iron, or an alloy containing these. A plurality of metal filter units 4 are provided, and each metal filter unit 4 is made of a different material and has a different thickness. The plurality of metal filter units 4 are stored in the memory unit 74 so that they can be identified by alphabets, numbers, or the like.

[0022] The metal filter part 4 is provided so as to be movable by a moving mechanism (not shown). For example, a ball screw mechanism driven by a servo motor can be used as the moving mechanism. The moving mechanism moves the metal filter part 4 of the material and thickness selected by a metal filter selection part 76 (described later) onto the optical axis of the radiation source 2. A radiation beam is irradiated onto the metal filter part 4 arranged on the optical axis, and the radiation beam that has passed through the metal filter part 4 is irradiated onto the object A to be inspected. By transmitting the radiation through the metal filter part 4, the occurrence of metal artifacts is suppressed.

[0023] The display unit 5 is, for example, a monitor such as a liquid crystal display or an organic EL display. The display unit 5 displays various images such as a fluoroscopic image, a CT image, and a 3D image of the object A, an imaging area, imaging conditions, etc. The display unit 5 may also display imaging conditions determined to be optimal by the control unit 7.

[0024] The input unit 6 may use a keyboard, a mouse, a touch panel, etc. The input unit 6 accepts image quality instructions (selection of fast, standard, fine, etc., selection by shooting time, etc.) from the user. The input unit 6 also accepts various operations such as menu selection for actual shooting or test shooting, setting of shooting conditions, manual operation of the moving mechanism, start of shooting, and selection of a part of the inspection object A to be observed.

[0025] The control unit 7 is configured with a computer and a driver circuit. The computer is configured with a storage such as an HDD or SSD, a RAM, a CPU, etc. The control unit 7 is connected to the input unit 6, and a user causes the control unit 7 to control each component of the X-ray inspection apparatus 100 via the input unit 6.

[0026] Fig. 3 is a block diagram showing the configuration of the control unit 7 in the first embodiment. As shown in Fig. 3, the control unit 7 includes an examination table control unit 71, a radiation source control unit 72, a pixel value calculation unit 73, a storage unit 74, and a material determination unit 75.

[0027] The inspection table controller 71 controls the rotation / lifting mechanism 12, the Y-shift mechanism 13, and the X-shift mechanism 14. Under the control of the inspection table controller 71, the object A placed on the inspection table 1 can be aligned with the optical axis of the radiation beam, and the object A can be rotated once during irradiation with the radiation beam. In addition, the distance (FCD) between the radiation source 2 and the object A can be adjusted under the control of the inspection table controller 71.

[0028] The radiation source control unit 72 controls the radiation source 2 to irradiate the object to be inspected A with a radiation beam. That is, under the control of the inspection table control unit 71 and the radiation source control unit 72, the object to be inspected A is irradiated with a radiation beam in all directions, and the detector 3 acquires a fluoroscopic image.

[0029] The pixel value calculation unit 73 creates a scan image based on a test scan, which will be described later, and calculates pixel values ​​in the scan image of the object A based on the scan image. For example, the pixel value calculation unit 73 creates a fluoroscopic image of the object A based on the amount of radiation received by the detector 3, and sets the pixel value calculated based on the result of the fluoroscopic image as the pixel value of the object A. The pixel value calculation unit 73 also calculates pixel values ​​in the scan image of the air based on the scan image. Note that the pixel value of the scan image of the object A is simply referred to as the pixel value of the object A, and the pixel value of the scan image of the air is referred to as the pixel value of the air. Then, the pixel value calculation unit 73 creates a histogram of the air and the object A as shown in FIG. 4. The vertical axis of this histogram is the number of pixels, and the horizontal axis is the pixel value. The pixel value calculation unit 73 calculates peak values ​​pa and pw of the number of pixels of the air and the object A from the histogram.

[0030] Then, the pixel value calculation unit 73 performs binarization using the peak value pa of air and half the peak value pw of the object A as a threshold value p, as shown in the following formula (1). The threshold value p is obtained and binarization is performed to extract the contour of the object A. The contour of the object A is the three-dimensional outer edge of the object A. Based on the contour of the object A obtained by binarization, the pixel value calculation unit 73 calculates the average pixel value CTmean of the object A within the contour. p = (p + pw) / 2 (1)

[0031] The memory unit 74 stores threshold values ​​used to determine the material of the object A to be inspected. The threshold values ​​are preset pixel values. For example, as shown in FIG. 5, the memory unit 74 stores two threshold values ​​Th1 and Th2. The threshold value Th1 indicates the boundary between plastic and standard, and the threshold value Th2 indicates the boundary between standard and heavy metal. The memory unit 74 stores the threshold values ​​Th1 and Th2 in association with the material of the object A to be inspected. The threshold values ​​are preset based on experience. The preset threshold values ​​may be updated.

[0032] The storage unit 74 also stores the type of metal filter portion 4 that is optimal for each material. For example, when the material of the test object A has a large atomic number and a high density, a metal filter portion 4 with a thick heavy metal is suitable, and accordingly, the storage unit 74 stores the optimal metal filter portion 4 for each material.

[0033] The storage unit 74 may store in advance types of metal filter units 4 corresponding to the image quality (fast, standard, fine) selected by the user, rather than having only one type of metal filter unit 4 corresponding to each material. Fig. 6 is a diagram showing the correspondence between the material of the object A to be inspected, the image quality selected by the user, and the metal filter unit 4. As shown in Fig. 6, for each material of the object A to be inspected, a metal filter unit 4 corresponding to the image quality (fast, standard, fine) may be set.

[0034] The storage unit 74 stores in advance optimal imaging conditions according to the metal filter unit 4 and image quality. The imaging conditions include various conditions such as tube voltage, tube current, binning, exposure time, number of views, number of accumulated images, and matrix size.

[0035] The material determination unit 75 determines the material of the object A based on the average pixel value CTmean of the object A calculated by the pixel value calculation unit 73 and the threshold values ​​Th1 and Th2 stored in the memory unit 74. If the average pixel value CTmean of the object A is lower than the threshold value Th1, the material determination unit 75 determines that the material of the object A is plastic, if the average pixel value CTmean is equal to or greater than the threshold value Th1 and equal to or less than Th2, the material determination unit 75 determines that the material of the object A is standard, and if the average pixel value CTmean is higher than the threshold value Th2, the material determination unit 75 determines that the material of the object A is heavy metal.

[0036] In this embodiment, when threshold value Th1 and the average pixel value CTmean are the same, and when threshold value Th2 and the average pixel value CTmean are the same, the material of the object A to be inspected is set to standard, but when threshold value Th1 and the average pixel value CTmean are the same, it may be set to plastic, and when threshold value Th2 and the average pixel value CTmean are the same, it may be set to heavy metal.

[0037] The metal filter selection unit 76 selects an optimal metal filter unit 4 based on the determination result of the material determination unit 75. The metal filter selection unit 76 controls the movement mechanism of the metal filter unit 4 to place the metal filter unit 4 corresponding to the material determined by the material determination unit 75 on the optical axis of the radiation.

[0038] Furthermore, the metal filter selection unit 76 determines whether the optimum metal filter unit 4 is further subdivided based on factors other than the material of the inspection object A, for example, the image quality selected by the user. If it is subdivided, the metal filter unit 4 associated with the image quality selection selected by the user is selected as the optimum metal filter unit 4. That is, in the example shown in Fig. 6, if the material of the inspection object A is plastic and the image quality selected by the user is fine, filter A3 is selected.

[0039] (action) Next, a description will be given of how to determine the material of the object A and how to select the metal filter portion 4. Fig. 7 is a flow chart relating to the determination of the material of the object A and the selection of the metal filter portion 4.

[0040] First, the object A to be inspected is placed on the sample table 11 of the inspection stage 1 (step S01). The object A to be inspected is adjusted so as to be positioned on the optical axis of the radiation by the rotation / elevation mechanism 12, the Y-shift mechanism 13, and the X-shift mechanism 14. Then, a test scan is started (step S02).

[0041] When the test scan is completed, the pixel value calculation unit 73 calculates the pixel values ​​of the air and the object A from the photographed result of the test scan, and obtains the pixel value pa which is the peak pixel number of the air and the pixel value pw which is the peak pixel number of the object A. Then, the pixel value calculation unit 73 calculates the threshold value p from each pixel value pa and pw based on the above formula (1), and binarizes and extracts the contour of the object A (step S03). This contour corresponds to the outer edge of the object A and is a three-dimensional region.

[0042] After extracting the contour of the object to be inspected A, the pixel value calculation unit 73 calculates an average pixel value CTmean from the pixel values ​​of the object to be inspected A within the contour (step S04). After the calculation of the average pixel value CTmean is completed, the material determination unit 75 determines the material of the object to be inspected A (step S05).

[0043] The material determination unit 75 compares the average pixel value CTmean with preset thresholds Th1 and Th2 to determine the material. For example, if the average pixel value CTmean is higher than Th2, the material of the inspection object A is determined to be heavy metal (see FIG. 5).

[0044] Once the material of the object A to be inspected has been determined, the metal filter selection unit 76 selects a metal filter unit 4 that corresponds to that material (step S06). The metal filter selection unit 76 also determines whether a metal filter unit 4 that is optimal for the image quality is set for each material of the object A to be inspected. If a metal filter unit 4 that corresponds to the image quality is set, the metal filter unit 4 that corresponds to the image quality selected by the user is selected.

[0045] Finally, the photographing conditions are automatically set according to the material of the object A to be inspected, which is stored in advance in the storage unit 74, and the image quality selected by the user (step S07). In this manner, the photographing conditions are set. Note that the various photographing conditions that are automatically set may be changed manually. An experienced user can photograph under more suitable photographing conditions.

[0046] (effect) As described above, the X-ray inspection apparatus 100 of this embodiment includes the radiation source 2 which irradiates the object A with X-rays, the detector 3 which is arranged facing the radiation source 2 across the object A, the metal filter section 4 which is arranged between the object A and the radiation source 2, the memory section 74 which stores the threshold values ​​Th1 and Th2 which are boundaries of pixel values ​​according to the material of the object A, the pixel value calculation section 73 which calculates the average pixel value CTmean of the object A from the imaging results, the material determination section 75 which compares the threshold values ​​Th1 and Th2 with the average pixel value CTmean to determine the material of the object A, and the metal filter selection section 76 which selects the metal filter section 4 corresponding to the material of the object A based on the determination result of the material determination section 75. The memory section 74 stores the metal filter section 4 which is optimal for the material of the object A in association with each other.

[0047] This allows the user to select the most suitable metal filter section 4 even when the material of the object A to be inspected is not known. This makes it possible to suppress the occurrence of artifacts and obtain clear images. In addition, because the most suitable metal filter section 4 is automatically selected, even inexperienced users can suppress the occurrence of artifacts.

[0048] Furthermore, the storage unit 74 stores the metal filter unit 4 that is optimal depending on the material of the inspection object A and the image quality selected by the user, and the metal filter selection unit 76 selects the metal filter unit 4 that corresponds to the material of the inspection object A and the image quality selected by the user. This makes it possible to select a more optimal metal filter unit 4, and more effectively suppress the occurrence of artifacts.

[0049] The memory unit 74 stores in advance the optimum imaging conditions according to the metal filter unit 4 and image quality. Therefore, the user does not need to set the imaging conditions such as the tube voltage, tube current, binning, exposure time, etc. individually. Therefore, even an inexperienced user can easily perform imaging, and an experienced user can shorten the work of setting the imaging conditions, improving the work efficiency.

[0050] Alternatively, instead of calculating the average pixel value CTmean, the pixel value pw at which the number of pixels of the object A peaks may be used as the pixel value of the object A, and the material of the object A may be determined by comparing this pixel value pw with the threshold values ​​Th1 and Th2. However, as in this embodiment, the pixel values ​​of the air and the object A are binarized, the contour of the object A is extracted, and the average pixel value CTmean within the contour is obtained, which allows the pixel values ​​of the object A to be compared with the threshold values ​​Th1 and Th2 to be calculated more accurately, and therefore the material can be determined more accurately. As a result, it becomes possible to select an optimal metal filter section 4, and artifacts can be suppressed more effectively.

[0051] Second embodiment Next, an X-ray inspection apparatus 100 according to a second embodiment will be described. The same configurations and functions as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. Fig. 8 is a side view showing the X-ray inspection apparatus according to the second embodiment. Fig. 9 is a top view showing the X-ray inspection apparatus according to the second embodiment. In Fig. 9, the imaging unit 8a is not shown.

[0052] 8 and 9, the X-ray inspection apparatus 100 of the second embodiment further includes an imaging unit 8. The imaging unit 8 captures an image of the inspection object A. The imaging unit 8 is a so-called camera, and an infrared (IR) camera, a CCD camera, or a CMOS camera can be used. Two imaging units 8 are provided.

[0053] As shown in FIG. 8, the imaging unit 8a is provided above the object to be inspected A, and the object to be inspected A is placed between the imaging unit 8a and the inspection table 1. The imaging unit 8a captures the object to be inspected A from above during a test scan. The imaging unit 8b is provided on the side of the metal filter unit 4, as shown in FIG. 9. The imaging unit 8b is provided at approximately the same height as the object to be inspected A. The imaging unit 8b captures the object to be inspected A from the side during a test scan.

[0054] 10 is a block diagram showing the configuration of the control unit 7 in the second embodiment. The control unit 7 further includes a size measurement unit 77, an optimal FCD calculation unit 78, and a scan count calculation unit 79.

[0055] The size measuring unit 77 measures the diameter D and height H of the object A to be inspected based on the image captured by the imaging unit 8. The measurement is performed based on the difference between an image taken before and an image taken after the object A is placed on the sample table 11. Since there is no change in the background image, the difference image of the background portion is 0, making it possible to extract the contour of the object A to be inspected. The size of one pixel of the captured image is stored in advance in the memory unit 74.

[0056] The size measuring unit 77 measures the diameter D of the object A to be inspected based on the image captured by the imaging unit 8a. The size measuring unit 77 measures the dimension of the object A to be inspected in a direction parallel to the mounting surface. The size measuring unit 77 then creates a circle circumscribing the dimension, and obtains the diameter D of this circle. The size measuring unit 77 also measures the height H from the top and bottom ends of the object A to be inspected in a direction perpendicular to the mounting surface, based on the image captured by the imaging unit 8b.

[0057] The optimum FCD calculation unit 78 calculates the optimum distance (FCD) from the focal point of the radiation source 2 to the center of the object A to be inspected from the diameter D of the object A measured by the size measurement unit 77. Fig. 11 is a top view showing the optimum FCD state. As shown in Fig. 11, the FCD is set so that the outer edge of the object A to be inspected (the outer edge of the diameter D) is inscribed in the radiation beam. By setting it in this way, it is possible to obtain a CT image with the highest resolution.

[0058] The optimum FCD calculation unit 78 calculates the angle θ of the radiation beam when the outer edge of the object A to be inspected is inscribed in the radiation beam based on the following formula (2). The values ​​of FDD and L may be preset values ​​or may be calculated from actual measured values. TIFF2025030413000002.tif41102FDD: Distance from the focus of radiation source 2 to detector 3 L: The length of the radiation detected by the detector 3 in a direction parallel to the placement surface and perpendicular to the optical axis of the radiation.

[0059] Then, the optimum FCD calculation unit 78 calculates the optimum FCD based on the following formula (3). TIFF2025030413000003.tif4193

[0060] The scan number calculation unit 79 calculates the number of times of imaging required to image the entire object A to be inspected in the FCD calculated by the optimal FCD calculation unit 78. Fig. 12 is a schematic side view of an X-ray inspection apparatus showing various parameters required for the scan number calculation unit 79 to calculate the number of times of imaging. The scan number calculation unit 79 calculates the angle θ of the radiation beam based on the following formula (4): h Request. TIFF2025030413000004.tif41107L h : Length of radiation detected by detector 3 in the height direction

[0061] Then, the scan number calculation unit 79 calculates the irradiation height t of the radiation beam irradiated to the inspection object A in imaging using the optimum FCD based on the following formula (5). TIFF2025030413000005.tif41136

[0062] Finally, the scan number calculation unit 79 compares the calculated irradiation height t with the height H of the object A measured by the size measurement unit 77. The scan number calculation unit 79 determines the number of scans to be the value obtained by rounding up the decimal point of the quotient of H / t. In other words, if the irradiation height t is equal to or less than the height H, it determines that the entire object A can be imaged with one cone beam scan. On the other hand, if the irradiation height t is greater than the height H, it determines that two or more cone beam scans are necessary.

[0063] Next, a method for calculating the number of scans will be described. First, the inspection object A is photographed by the imaging units 8a and 8b without being placed on the sample table 11. Then, the inspection object A is placed on the sample table 11, and the inspection object A is photographed by the imaging units 8a and 8b. This photographing may be performed simultaneously with the test photographing in step S02 of FIG. 7 in the first embodiment.

[0064] When the imaging units 8a and 8b have completed capturing images, the size measurement unit 77 measures the diameter D and height H of the object A to be inspected based on the pixel size stored in the memory unit 74. When the diameter D of the object A to be inspected is calculated, the optimum FCD calculation unit 78 sets the optimum FCD so that the outer edge of the object A to be inspected is inscribed in the radiation beam. The optimum FCD is calculated using the above formulas (2) and (3).

[0065] When the optimal FCD is calculated, the scan number calculation unit 79 calculates the number of scans required to capture an image of the entire object A at the calculated FCD. The scan number calculation unit 79 first calculates the irradiation height t based on the above formulas (4) and (5). Then, the scan number calculation unit 79 compares the calculated irradiation height t with the height H of the object A measured by the size measurement unit 77, and calculates the required number of scans.

[0066] Finally, the radiation source 2 or the object A to be inspected is moved based on the results of the optimum FCD calculation unit 78 and the scan count calculation unit 79. Note that the calculation of the scan count in this embodiment may be performed prior to, after, or simultaneously with the determination of the material of the metal filter part 4 in the first embodiment.

[0067] As described above, the X-ray inspection apparatus 100 of this embodiment further includes the imaging unit 8, a size measurement unit 77 that measures the diameter D and height H of the object A to be inspected based on the imaging results of the imaging unit 8, and an optimal FCD calculation unit 78 that calculates an optimal FCD based on the measurement results of the size measurement unit 77. This makes it possible to acquire a clear image. In addition, since the FCD is automatically adjusted to an optimal value without the user having to adjust the position, the effort of setting imaging conditions is eliminated, improving operability.

[0068] Furthermore, the X-ray inspection apparatus 100 of this embodiment includes a scan number calculation unit 79 that calculates the number of scans required to capture an image of the entire inspection object A in the imaging at the calculated optimal FCD. This allows the user to easily grasp the number of imaging times in the optimal FCD. Therefore, imaging can be easily performed.

[0069] (Other embodiments) In this specification, an embodiment of the present invention has been described, but this embodiment is presented as an example and is not intended to limit the scope of the invention. The above-mentioned embodiment can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the scope of the invention. The embodiment and its modifications are included in the scope of the invention and its equivalents described in the claims, as well as in the scope and gist of the invention.

[0070] In the first embodiment, the material is determined by two threshold values ​​Th1 and Th2, but the number of threshold values ​​may be set to three or more. The material of the object A to be inspected is subdivided, and a more optimal metal filter portion 4 can be selected.

[0071] In the above second embodiment, two imaging units 8 are provided, but only one imaging unit 8 may be provided as long as the diameter D and height H of the inspection object A can be measured. In this case, the X-ray inspection apparatus 100 can be simplified and made smaller. Furthermore, the number of imaging units 8 can be reduced, leading to cost reduction. [Explanation of symbols]

[0072] 1 Examination table 11 Sample table 12 Rotation and lifting mechanism 13 Y-shift mechanism 14 X-shift mechanism 2 Radiation source 3. Detector 4 Metal filter part 5 Display section 6 Input section 7 Control section 71 Examination table control unit 72 Radiation Source Control Section 73 Pixel value calculation unit 74 Memory section 75 Material determination section 76 Metal Filter Selection Section 77 Size measurement section 78 Optimal FCD Calculation Section 79 Scan Count Calculation Unit 8, 8a, 8b Imaging section A. Inspection item

Claims

1. A radiation source that irradiates an object to be inspected with X-rays; a detector disposed opposite the radiation source across the object to be inspected; a metal filter portion disposed between the object to be inspected and the radiation source; a storage unit that stores a threshold value that is a boundary between pixel values ​​according to a material of the object to be inspected; a pixel value calculation unit that calculates pixel values ​​of the object to be inspected from the imaging result; a material determination unit that determines a material of the object to be inspected by comparing the threshold value with a pixel value of the object to be inspected; a metal filter selection unit that selects the metal filter unit corresponding to the material of the object to be inspected based on a determination result from the material determination unit; Equipped with The memory unit stores the metal filter unit that is optimal for a material of the object to be inspected in association with the material of the object to be inspected.

2. the pixel value calculation unit extracts a contour of the object to be inspected from pixel values ​​of air and the object to be inspected, and calculates an average pixel value of the object to be inspected within the contour; the material determination unit compares the average pixel value with the threshold value to determine the material of the object to be inspected.

2. The X-ray inspection apparatus of claim 1.

3. an imaging unit that images the object to be inspected; a size measuring unit that measures a diameter and a height of an object to be inspected based on an image captured by the imaging unit; an optimal FCD calculation unit that calculates an optimal distance (FCD) from the focal point of the radiation source to the object to be inspected based on the diameter of the object to be inspected measured by the size measurement unit; The X-ray inspection apparatus according to claim 1 or 2, further comprising:

4. 4. The X-ray inspection apparatus according to claim 3, further comprising a scan number calculation unit that calculates, from a height of the object to be inspected, a number of scans required to image an entire object to be inspected in the FCD calculated by the optimal FCD calculation unit.

5. further comprising an input unit for receiving image quality selection from a user; the storage unit stores the metal filter unit that is optimal depending on the material of the object to be inspected and the image quality in association with each other.

3. An X-ray inspection apparatus according to claim 1 or 2.

Images