Imaging device, imaging method, and imaging program

Abstract

The present invention provides an imaging device, imaging method, and imaging program that reduce blurring of transmission images and improve the accuracy of thickness and depth calculations. [Solution] The system comprises a radiation source, a detector for radiation emitted from the radiation source, a depth measuring device for measuring the depth of an object placed between the radiation source and the detector in the depth direction from the radiation source to the detector, and an image processing unit that calculates the brightness of each pixel before the change based on the linear relationship between the depth and the amount of change in brightness of each pixel, using the depth at which the depth of the object in the depth direction from the radiation source to the detector is changed two or more times, and the brightness of each pixel in each transmission image of the object generated by the detector at each of the depths, and generates an image that removes the blurriness of the object's boundary.

Description

Technical Field

[0001] The present invention relates to a photographing apparatus, a photographing method, and a photographing program.

Background Art

[0002] Currently, in the evaluation of the interior of an automobile, destructive inspection is mainly used, resulting in a heavy work burden, high costs, and the generation of waste. In contrast, a technique for analyzing the luminance of an X-ray transmission photographing image and non-destructively inspecting the internal thickness based on known information has been disclosed (see Patent Document 1). In the thickness calculation technique, there are cases where the shape cannot be accurately calculated due to the phenomenon that the transmission photographing image of the measurement object becomes unclear. One of the causes for the transmission photographing image of the object to become unclear is that the focus size of the irradiated X-ray has a finite size.

[0003] As shown in FIG. 10, the X-ray generation unit 1002 of the X-ray generation apparatus 1001 has a finite size. When the X-ray irradiated to the end portion 1004 of the object 1003 reaches the detector 1005, due to the spatial spread of the X-ray generation unit 1002, the transmission image of the object detected by the detector 1005 becomes unclear because the X-ray transmission intensity gradually changes near the boundary of the object. As shown in FIG. 11, the thickness of the object obtained from the transmission image is calculated as if the thickness also changes similarly in the region where the transmission image becomes unclear. FIG. 11(a) is a graph showing the change in thickness with respect to the position when the distance between the object and the detector (Object to Detector Distance, ODD) is large, and FIG. 11(b) is a graph showing the change in thickness with respect to the position when the ODD is small. Here, FOD in the figure is the distance between the object and the X-ray generation apparatus (Focus to Object Distance), and FDD is the distance between the detector and the X-ray generation apparatus (Focus to Detector Distance).

[0004] To address the phenomenon of blurred transmission images, there are methods to reduce blurring by decreasing the ODD (Optical Distance) and methods to reduce the focus size of the X-ray source. Furthermore, Patent Document 1 proposes a method for correcting blurred transmission images in post-processing, in which the degree of blurring is geometrically calculated from the relative positions of the object, detector, and X-ray source, and then corrected. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2011-036407 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] However, while reducing obscuration by decreasing the ODD can reduce obscuration, the distance between the object and the detector becomes smaller, causing scattered X-rays from the object to reach the detector, which act as disturbances that change the brightness and reduce the accuracy of thickness calculation. While reducing the focus size of the X-ray source can reduce obscuration, the energy is concentrated in a narrow area on the target inside the X-ray tube, resulting in high temperatures, making it difficult to set a high current value. Furthermore, the technical difficulty is high, and the price of the X-ray tube is also high. In the method proposed in Patent Document 1, which geometrically calculates and corrects the degree of obscuration, it is difficult to distinguish and process brightness changes caused by actual gradual thickness changes and brightness changes caused by obscuration for objects with three-dimensionally complex structures such as automobile parts.

[0007] In view of the above problems, the present invention aims to provide an imaging device, imaging method, and imaging program that can reduce the blurring of transmitted images and improve the accuracy of thickness calculation and depth calculation. [Means for solving the problem]

[0008] A first aspect of the present invention is an imaging device comprising: a radiation source; a detector for radiation emitted from the radiation source; a depth measuring instrument for measuring the depth of an object placed between the radiation source and the detector in the depth direction from the radiation source to the detector; and an image processing unit that generates an image by calculating the brightness of each pixel before the change, based on a linear relationship between the depth and the amount of change in brightness of each pixel, from the depth of the object when the depth from the radiation source to the detector is changed two or more times, and the brightness of each pixel of each transmission image of the object generated by the detector at each of the depths, thereby removing the blurriness of the object's boundary.

[0009] In a first embodiment of the present invention, the image processing unit may calculate the brightness before the change after correcting for the non-uniformity of the radiation intensity at each position of the detector by dividing the brightness of each pixel of each transmission image by the brightness of each pixel of the image generated by the detector when no object is placed between the radiation source and the detector.

[0010] In a first aspect of the present invention, the image processing unit may enlarge or reduce each of the other transmission images (excluding the one transmission image) generated at each depth to make the sizes of the transmission images the same, and then calculate the brightness before the change.

[0011] In a first embodiment of the present invention, a position control unit may be provided that changes the position of an object in the depth direction between the radiation source and the detector while keeping the distance between the radiation source and the detector constant.

[0012] In a first aspect of the present invention, the image processing unit determines the distance between the radiation source and the detector as L0, the distance between the radiation source and the object at each depth as follows: the distance between the radiation source and the object on the side of the depth closer to the radiation source is the first distance L1, and the distance between the radiation source and the object on the side of the depth further from the radiation source is the second distance L2. When the object is located at the first distance and the second distance, the brightness of each desired pixel in the transmission image is M1 and M2, respectively. The brightness of the desired pixel before change is calculated by the following formula: t You may calculate this.

[0013]

number

[0014] A second aspect of the present invention is a photographic method comprising: a depth measurement step in which a computer capable of communicating with a radiation source and a detector of radiation emitted from the radiation source measures the depth of an object placed between the radiation source and the detector in the depth direction from the radiation source to the detector; and an image processing step in which the brightness of each pixel before the change is calculated from the depth of the object in the depth direction from the radiation source to the detector, based on a linear relationship between the depth and the amount of change in brightness of each pixel, and an image is generated to remove the blurriness of the object's boundary.

[0015] A third aspect of the present invention is a photographing program, which is executed on a computer capable of communicating with a radiation source and a detector for detecting radiation emitted from the radiation source. The program includes a depth measurement function for measuring the depth of an object placed between the radiation source and the detector in the depth direction from the radiation source toward the detector, and an image processing function for generating an image that removes the blurriness of the boundary of the object by calculating the luminance of each pixel of the transmission image of the object generated by the detector at each depth when the depth of the object in the depth direction from the radiation source toward the detector is changed two or more times, and calculating the change amount of each luminance of each pixel, and calculating the luminance of each pixel before the change based on the linear relationship between the depth and the change amount of each luminance, and generating an image that removes the blurriness of the boundary of the object.

[0016] According to the present invention, it is possible to provide a photographing device, a photographing method, and a photographing program that can reduce the blurring of a transmission image and improve the accuracy of thickness calculation and depth calculation.

Brief Description of the Drawings

[0017] [Figure 1] It is a schematic diagram of an example of a photographing device according to a first embodiment of the present invention. [Figure 2] It is a schematic diagram showing the positional relationship of each of the radiation source, the detector, and the object shown in FIG. 1. [Figure 3] It is a block diagram for explaining an imaging device 10 according to the present embodiment. [Figure 4] It is a diagram of an example of a transmission image when an object is installed between a radiation source and a detector. [Figure 5] It is a transmission image of an object. FIGS. 5(a), 5(b), and 5(c) are transmission images when the object 103 is placed at each of positions A, B, and C. [Figure 6] It is an enlarged view of FIGS. 5(a) and 5(b) shown in FIG. 6. [Figure 7] It is a graph showing the relationship between the luminance and ODD at a plurality of pixels on the transmission image shown in FIG. 6. [Figure 8]FIG. 8(a) is a transmission image before execution of a process for calculating true luminance values for the transmission image shown in FIG. 6, and FIG. 8(b) is a transmission image after the process. [Figure 9] This is a flowchart for explaining the imaging method according to the present embodiment. [Figure 10] This is a schematic diagram for explaining the cause of the transmission image becoming unclear. [Figure 11] This is a graph showing changes in the calculated thickness of an object due to the unclear state of the transmission image. FIG. 11(a) shows the change in thickness with respect to position when the ODD is large, and FIG. 11(b) shows the change in thickness with respect to position when the ODD is small.

Mode for Carrying Out the Invention

[0018] Next, embodiments of the present invention will be described with reference to the drawings. In the description of the drawings according to the embodiments, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationships such as the relationship with the planar dimensions are different from the actual ones. Therefore, specific dimensions should be determined in consideration of the following description. Of course, the drawings also include parts where the relationships and ratios of the dimensions to each other are different.

[0019] Furthermore, the embodiments illustrate devices and methods for embodying the technical idea of the present invention, and the technical idea of the present invention does not specify the configuration, arrangement, layout, etc. of each component as the following. The technical idea of the present invention can be variously modified within the technical scope defined by the claims described in the claims.

[0020] (Embodiment) The imaging device according to the present embodiment is a device that calculates a transmission image from which the influence of unclear imaging has been removed from transmission images obtained by imaging an object at a plurality of ODDs, using the fact that the degree of unclear imaging of the transmission image due to radiation irradiation changes depending on the distance (ODD) between the object and the radiation detector. [[ID=二十九]]

[0021] Figure 1 shows a schematic diagram illustrating the outline of the imaging device according to this embodiment. As shown in Figure 1, the imaging device 10 according to this embodiment, as an example, includes a radiation source 101, a detector 102 for radiation emitted from the radiation source 101, a depth measuring instrument 104 for measuring the depth of an object 103 placed between the radiation source 101 and the detector 102 in the depth direction from the radiation source 101 to the detector 102, and the brightness of each pixel in each transmission image of the object 103 generated by the detector 102 at each depth, and the brightness of each pixel before the change M t The system includes a processing unit 105 that calculates and generates an image that removes the blurriness of the target object.

[0022] The imaging device 10 may be, for example, a device that captures a transmission image of the object 103 (for example, a component and the void inside the component). The imaging device 10 is not limited to the example device described above, but may consist of various other devices.

[0023] The radiation source 101 may be, for example, an X-ray source that emits X-rays. However, the radiation emitted by the radiation source 101 is not limited to X-rays, and may be other wavelengths different from X-rays (for example, gamma rays, alpha rays, beta rays, and neutron rays).

[0024] The detector 102 detects radiation emitted from the radiation source 101. For example, the detector 102 may be an X-ray detector that detects X-rays emitted from the radiation source 101 (X-ray source). If there is an object 103 (member) between the detector 102 and the radiation source 101, the detector 102 generates information about a transmitted image (transmitted X-ray image) based on the radiation (X-rays) that has passed through the object 103.

[0025] The depth measuring device 104 measures the depth of the object 103 from the radiation source 101 to the detector 102, that is, the distance between the object 103 and the detector 102. The depth measuring device 104 may be a device that performs measurements using sensors such as an optical sensor or an acoustic sensor.

[0026] The processing unit 105 may be a computer (information processing device) such as a server, desktop, laptop, tablet, or smartphone. The processing unit 105 can send and receive information with, for example, the radiation source 101, the detector 102, and the depth measuring instrument 104, and controls the radiation source 101, the detector 102, and the depth measuring instrument 104. The processing unit 105 also performs various calculations using image information generated by the detector 102. One example of the calculation is to obtain the depth of the object 103 in the depth direction Y and each transmission image of the object 103 generated by the detector 102 at each depth, and then use the brightness of each pixel in each transmission image to calculate the brightness M of each pixel before the change, based on the linear relationship between the depth and the amount of change in brightness of each pixel. t This could involve a process that calculates a value and generates an image that removes the blurriness of the object's boundaries.

[0027] First, the object 103 (component) is placed between the radiation source 101 and the detector 102. Figure 2 shows the relative positions of the radiation source 101, the detector 102, and the object 103 as shown in Figure 1. In Figure 2, as an example, the object 103 is a plate with a uniform thickness, and is positioned so that the surface of the plate shape of the object 103 is perpendicular to the y-axis. The distances of the object 103 from the radiation source 101 and the detector 102 are, in order, positions A, B, and C, and transmission images are captured at each position. The distances between the detector 102 and the object 103 when the object 103 is placed at positions A, B, and C are L1, L2, and L3, respectively.

[0028] The processing unit 105 controls the radiation source 101 to emit radiation when the object 103 is positioned at location A. The detector 102 generates a transmission image (first A transmission image) (first A transmission image information) of the radiation that has passed through the object 103, in response to the radiation emitted from the radiation source 101. The processing unit 105 obtains the first A transmission image information from the detector 102 and obtains the distance L1 from the depth measuring instrument 104.

[0029] Next, the object 103 (member) is moved. That is, the object 103 (member) is positioned at position B, which is a distance L2 away from the detector 102 in the depth direction Y (negative direction (see Figure 1) or positive direction).

[0030] The processing unit 105 controls the radiation source 101 to emit radiation when the object 103 is positioned at position B, as described above. The detector 102 generates a transmission image (first B transmission image) (first B transmission image information) of the radiation that has passed through the object 103, in response to the radiation emitted from the radiation source 101. The processing unit 105 obtains second transmission image information from the detector 102 and obtains the distance L2 from the depth measuring instrument 104.

[0031] Furthermore, the object 103 (member) is moved. That is, the object 103 (member) is positioned at a location C at a distance L3 from the detector 102 in the depth direction Y (negative direction (see Figure 1) or positive direction).

[0032] The processing unit 105 controls the radiation source 101 to emit radiation when the object 103 is positioned at position C, as described above. The detector 102 generates a transmission image (first C transmission image) (first C transmission image information) of the radiation that has passed through the object 103, in response to the radiation emitted from the radiation source 101. The processing unit 105 obtains third transmission image information from the detector 102 and obtains the distance L3 from the depth measuring instrument 104.

[0033] The processing unit 105 generates an image that removes the blurriness of the object based on the 1A transmission image information, 1B transmission image information, and 1C transmission image information acquired from the detector 102, and the distances L1, L2, and L3 acquired from the depth measuring instrument 104.

[0034] Next, an imaging device 10 according to one embodiment will be described in detail. In particular, the processing unit 105 will be described. Figure 3 is a block diagram illustrating an imaging device 10 (processing unit 105) according to one embodiment.

[0035] The imaging device 10 (processing unit 105) includes, for example, a communication unit 121, a storage unit 122, a display unit 123, and a control unit 110. The communication unit 121, the storage unit 122, and the display unit 123 may be embodiments of the output unit. The control unit 110 includes, for example, a radiation source control unit 111, an acquisition unit 112, a first image generation unit 113, a second image generation unit 114, a position control unit 115, and an output control unit 116. The control unit 110 may be configured by, for example, the arithmetic processing unit of the imaging device 10. The control unit 110 (for example, the arithmetic processing unit) may realize the functions of each unit (for example, the radiation source control unit 111, the acquisition unit 112, the position control unit 115, and the output control unit 116) by appropriately reading and executing various programs stored in, for example, the storage unit 122. In other words, the functions of each unit may be realized by computer implementation.

[0036] The communication unit 121 is a communication interface that enables the transmission and reception of various types of information with, for example, an external device located outside the imaging device 10. The external device may be, for example, a radiation source 101, a detector 102, a server (not shown), and a user terminal (not shown).

[0037] The storage unit 122 may store, for example, various information and programs. Examples of the storage unit 122 include memory, solid-state drives, and hard disk drives. The storage unit 122 may also be, for example, a storage area and server located in the cloud.

[0038] The display unit 123 is a display capable of displaying various characters, symbols, images, etc.

[0039] The radiation source control unit 111 controls the radiation source 101 to emit radiation via the communication unit 121 when the object 103 is located at any of the locations A, B, or C described later.

[0040] The detector 102 generates a transmission image (transmission image information) based on detecting radiation that has passed through the object 103. In this case, the detector 102 may generate a first A transmission image (first A transmission image information) when the object 103 is located at position A. The detector 102 may also generate a first B transmission image (first B transmission image information) when the object 103 is located at position B. The detector 102 may also generate a first C transmission image (first C transmission image information) when the object 103 is located at position C. The image of the object 103 is recorded in each of the first A transmission image, the first B transmission image, and the first C transmission image.

[0041] The acquisition unit 112, for example, via the communication unit 121, acquires first A transmission image information from the detector 102 and distance L1 from the depth measuring instrument 104 when the object 103 is located at position A; acquires first B transmission image information from the detector 102 and distance L2 from the depth measuring instrument 104 when the object 103 is located at position B; and acquires first C transmission image information from the detector 102 and distance L3 from the depth measuring instrument 104 when the object 103 is located at position C.

[0042] The first image generation unit 113 generates a second A transparent image (second A transparent image information), a second B transparent image (second B transparent image information), and a second C transparent image (second C transparent image information) based on the first A transparent image information, first B transparent image information, third transparent image information, distance L1, distance L2, and distance L3 acquired by the acquisition unit 112, such that the size of the image of the object 103 recorded in the first A transparent image, first B transparent image, and first C transparent image are the same.

[0043] The second image generation unit 114 generates a third transparent image that removes the blurriness of the object's boundary based on the distances L1, L2, and L3 acquired by the acquisition unit 112, and the second A transparent image information, second B transparent image information, and second C transparent image information generated by the first image generation unit 113.

[0044] The operation of the first image generation unit 113 and the second image generation unit 114 will now be described.

[0045] Let L0 be the distance between the radiation source 101 and the detector 102, L1 be the distance between the object 103 and the detector 102 when the object 103 is at position A, L2 be the distance between the object 103 and the detector 102 when the object 103 is at position B, and L3 be the distance between the object 103 and the detector 102 when the object 103 is at position C. Assume that the thickness of the object 103 is uniform in the x-direction as shown in Figure 2.

[0046] Regions M, N, and P are defined as areas on the object 103 with a size of one pixel in the x-axis direction. Region M is the area where X-rays irradiated from the X-ray generating unit 301 of the radiation source 101 to the detector 102 in a direction parallel to the y-axis as shown in Figure 2 pass through the object 103. Regions N and P are areas located at a greater distance from the X-ray generating unit 301 compared to region M.

[0047] X-rays are emitted from the X-ray generator 301. Region M of the object 103 located at position C is irradiated onto region M1 on the detector 102. X-rays that pass through region M of the object 103 located at position B are irradiated onto region M2 on the detector 102. X-rays that pass through region M of the object 103 located at position A are irradiated onto region M3 on the detector 102. Regions M1, M2, and M3 are located at the same location on the detector 102, and since region M1 has the largest area among regions M1, M2, and M3, only region M1 is shown in Figure 2.

[0048] X-rays emitted from the X-ray generator 301 that pass through region N of the object 103 located at position C irradiate region N1 on the detector 102, X-rays that pass through region N of the object 103 located at position B irradiate region N2 on the detector 102, and X-rays that pass through region N of the object 103 located at position A irradiate region N3 on the detector 102. Similarly, X-rays emitted from the X-ray generator 301 that pass through region P of the object 103 located at position C irradiate region P1 on the detector 102, X-rays that pass through region P of the object 103 located at position B irradiate region P2 on the detector 102, and X-rays that pass through region P of the object 103 located at position A irradiate region P3 on the detector 102.

[0049] Furthermore, the region where X-rays irradiated from the X-ray generating unit 301 reach the detector 102 without passing through the object 103 is defined as region Q.

[0050] Figure 4 is an example of a transmission image 401 when an object 103 is placed between the radiation source 101 and the detector 102. For example, if the object 103 is located at position B as shown in Figure 2, then regions M, N, and P on the transmission image 401 shown in Figure 4 correspond to regions M2, N2, and P2 in Figure 2. Also, region Q corresponds to region Q as shown in Figure 2.

[0051] The transmission image shown in Figure 4 represents the intensity of the irradiated X-rays that reached the object 103 as brightness. Region 402 of the transmission image 401 is the region where the irradiated X-rays passed through the object 103 and reached the detector 102. Region 403 of the transmission image 401 is the region where the irradiated X-rays reached the detector 102 without passing through the object 103. The dashed line 404 is the boundary of the object 103, but in region 404 including the dashed line 404, the brightness of the transmission image 401 is distorted, resulting in blurring in the transmission image 401. Because of this blurring, it is difficult to calculate the shape and thickness of the object 103 based solely on the brightness distribution of the transmission image 401. The imaging apparatus according to this embodiment generates an image that removes this blurring by following the procedure below.

[0052] As shown in Figure 2, the object 103 is moved to position A, then position B, then position C, and the transmission images obtained at each position are shown in Figure 5. Figures 5(a), 5(b), and 5(c) are the transmission images when the object 103 is placed at positions A, B, and C, respectively. As shown in Figure 5, the size of the object 103 shown in the transmission image when the object 103 is placed at position A is the smallest, and the size increases as the position of the object 103 is changed to position B, then position C, and so on.

[0053] The relative sizes of the objects 103 shown in each transmission image in Figure 5 are determined by the distance between the X-ray irradiation unit, the detector, and the object. Therefore, the size of the objects 103 shown in each transmission image in Figure 5 is enlarged or reduced to the same size as each other. Here, as an example, the sizes of images A and B are enlarged so that they are the same size as image C. The enlarged images A2, B2, and C are shown in Figure 6.

[0054] Figure 7 shows a graph of the obtained transmission images, where the average brightness within each region (M1, M2, M3, N1, N2, N3, P1, P2, P3, Q1, Q2, and Q3) is displayed against the distance (ODD) between the object 103 and the detector 102 when each region was photographed.

[0055] As shown in Figure 7, the luminance values ​​in regions M1, M2, and M3 are small and do not change even when the ODD is changed. Similarly, the luminance values ​​in regions Q1, Q2, and Q3 are large and do not change even when the ODD is changed. On the other hand, the luminance in regions N1, N2, N3, P1, P2, and P3 changes in proportion to the change in the ODD.

[0056] As shown in Figure 7, when the relationship between the luminance value at each position on the transmitted image, i.e., each pixel, and the ODD is linearly approximated, the luminance value at ODD=0 is considered to be the true luminance value from which the blurring that occurred in the transmitted image 401 has been removed.

[0057] When transmission imaging is performed by reducing the distance between the object and the detector, scattered X-rays emitted from the object reach the detector, changing its brightness and causing new blurring. This method eliminates blurring caused by the finite spread of the X-ray source's focus size, without being affected by scattered X-rays from the object.

[0058] Figure 8 shows the transparent image before and after processing, where the true luminance value is calculated for each pixel in the transparent image shown in Figure 6, based on the linear relationship between the luminance value of each pixel and the ODD. Figure 8(a) is the transparent image before processing, and Figure 8(b) is the transparent image after processing. Here, the true luminance value M is the luminance value before change M t It can be expressed as follows, and the true luminance value M may be determined from the luminance value of each pixel and ODD based on the following relationship.

[0059] The image processing unit determines the distance between the radiation source and the detector as L0, the distance between the radiation source and the object at each depth as follows: the distance between the radiation source and the object on the side of the depth closer to the radiation source is defined as the first distance L1, and the distance between the radiation source and the object on the side of the depth further from the radiation source is defined as the second distance L2. If the brightness of the desired pixels in the transmission image when the object is located at the first distance and the second distance are M1 and M2, then the pre-change brightness M of the desired pixel is calculated using the following formula. t teeth,

[0060]

number

[0061] It is represented as follows.

[0062] The above formula can be used when an object is placed between a radiation source and a detector, a transmission image is taken, the ODD is changed and another transmission image is taken, and an image with the blurred boundaries of the object removed is obtained by using transmission images for two patterns of ODD. When using transmission images for three or more patterns of ODD, the brightness value of each pixel in the transmission image can be used to calculate the brightness value for which ODD=0 for each pixel using a linear relationship with ODD, for example, by the least squares method, and this can be used as the brightness value with the blurred boundaries removed.

[0063] The boundaries are sharpened, and in areas where the thickness of the object is distorted, the brightness values ​​are also distorted in the transmission image, resulting in brightness values ​​corresponding to the thickness of the object.

[0064] When calculating an image that removes the aforementioned blurriness, as shown in Figure 4, a transmission image may be taken of only the background without placing the object between the X-ray irradiation device and the detector, prior to the process of making the object sizes the same for multiple transmission images obtained by taking images with different ODDs, as shown in Figure 5. Then, the brightness value of each pixel in the background-only transmission image may be divided by the brightness value of each pixel in the multiple transmission images obtained by taking images with different ODDs. This process can remove the spatial inhomogeneity of the intensity of the X-rays irradiated from the X-ray irradiation device.

[0065] Furthermore, when calculating the image with the aforementioned blurring removed, as shown in Figure 4, three scans are performed with different ODDs, and the calculation is based on three patterns of transmission images. However, at least two patterns of transmission images are necessary to calculate an image with the blurring removed. By performing three or more scans with different ODDs and calculating based on three or more patterns of transmission images, the accuracy of the linear approximation is improved compared to calculation based on two patterns of transmission images, and a transmission image can be obtained in which the blurring caused by the finite spread of the X-ray source's focus size is accurately removed.

[0066] In this embodiment, the position control unit 104 is shown to move only the object 103 by a predetermined distance along the depth direction Y while keeping the distance between the radiation source 101 and the detector 102 constant. In this case, for example, the positions of the radiation source 101 and the detector 102 may be fixed. In this case, the object 103 may be placed on a jig that can move between the radiation source 101 and the detector 102 in the depth direction Y (positive depth direction (+) and negative depth direction (-)). The position control unit 115 may control the jig to move by a predetermined distance.

[0067] Alternatively, the position control unit 104 may fix the object 103 in place while moving the radiation source 101 and the detector 102 by a predetermined distance. In this case, for example, the position control unit 105 may fix the radiation source 101 and the detector 102 to the tip of the robot arm, fix the object 103 in place, and control the robot arm to move the radiation source 101 and the detector 102 by a predetermined distance.

[0068] Next, a shooting method according to one embodiment will be described. Figure 9 is a flowchart illustrating a shooting method according to one embodiment.

[0069] In step ST101, the position control unit 105 fixes the object 103 at a predetermined position (position A) between the radiation source 101 and the detector 102, while keeping the distance between the radiation source 101 and the detector 102 constant in the depth direction Y.

[0070] In step ST102, the radiation source control unit 111 controls the radiation source 101 to emit radiation when the object 103 is located at position A. The detector 102 generates a transmission image (first transmission image) (first transmission image information) based on detecting the radiation that has passed through the object 103.

[0071] In step ST103, the position control unit 105 moves the object 103 and fixes it at position B. The position control unit 105 controls the position of the object 103 in the depth direction between the radiation source 101 and the detector 102, while keeping the distance between the radiation source 101 and the detector 102 constant. In other words, the position control unit 105 moves the position of the object 103 relative to the radiation source 101 and the detector 102.

[0072] In step ST104, the radiation source control unit 111 controls the radiation source 101 to emit radiation when the object 103 is located at position B. The detector 102 generates a transmission image (second transmission image) (second transmission image information) based on detecting the radiation that has passed through the object 103.

[0073] In step ST105, the acquisition unit 112 acquires first A transmission image information from the detector 102 and distance L1 from the depth measuring instrument 104. If the object 103 is located at position B, it acquires first B transmission image information from the detector 102 and distance L2 from the depth measuring instrument 104.

[0074] In step ST106, the first image generation unit 113 generates a second A transparent image (second A transparent image information) and a second B transparent image (second B transparent image information) based on the first A transparent image information, first B transparent image information, distance L1, and distance L2 acquired by the acquisition unit 112, such that the size of the image of the object 103 recorded in the first A transparent image and the first B transparent image are the same.

[0075] In step ST107, the second image generation unit 114 generates a third transparent image that removes the blurriness of the object's boundary based on the distances L1 and L2 acquired by the acquisition unit 112, and the second A transparent image information and second B transparent image information generated by the first image generation unit 113.

[0076] [Differentiation] In the embodiment described above, the imaging device 10 emits radiation such as X-rays from a radiation source 101 and detects the radiation (for example, transmitted radiation such as transmitted X-rays) that has passed through a material (object 103) such as metal or resin with a detector 102. This makes it possible for the imaging device 10 to measure the depth of the material (object 103) and the depth of the void (object 103) inside the material.

[0077] As a modified example, the imaging device 10 may include a light source capable of emitting light such as ultraviolet light, visible light, and infrared light, and a light receiver for detecting the light emitted from the light source. In this case, the depth measuring device 1 may emit light from the light source and detect the transmitted light that has passed through a component (object) such as a semiconductor or glass with the light receiver. Similarly, as a modified example, the imaging device 10 may also include an electromagnetic wave source capable of emitting electromagnetic waves of various wavelengths, and a detector for detecting the electromagnetic waves emitted from the electromagnetic wave source. In this case, the depth measuring device 1 may emit electromagnetic waves from the electromagnetic wave source and detect the transmitted electromagnetic waves that have passed through the material (object) with a photodetector. This enables the imaging device 10 to measure the depth of the component (object) and the depth of the void (object) inside the component.

[0078] [Regarding functions and circuitry] Next, the functions and circuitry of the aforementioned imaging device 10 will be described. Each part of the imaging device 10 may be implemented as a function of a computer's processing unit or the like. That is, the radiation source control unit 111, acquisition unit 112, first image generation unit 113, second image generation unit 114, position control unit 115, and output control unit 116 (control unit 110) of the imaging device 10 may be implemented as a radiation source control function, acquisition function, first image generation function, second image generation function, position control function, and output control function (control function), respectively, by a computer's processing unit or the like. The shooting program can enable a computer to implement each of the functions described above. The shooting program may be recorded on a computer-readable, non-temporary storage medium, such as memory, a solid-state drive, a hard disk drive, or an optical disc. The storage medium can be rephrased as, for example, a non-temporary, computer-readable medium for storing the shooting program. Furthermore, the shooting program may be transmitted online. Furthermore, as described above, each part of the imaging device 10 may be implemented by a computer's arithmetic processing unit or the like. This arithmetic processing unit or the like is composed of, for example, an integrated circuit. For this reason, each part of the imaging device 10 may be implemented as a circuit that constitutes the arithmetic processing unit or the like. That is, the radiation source control unit 111, acquisition unit 112, first image generation unit 113, second image generation unit 114, position control unit 115, and output control unit 116 (control unit 110) of the imaging device 10 may be implemented as a radiation source control circuit, acquisition circuit, first image generation circuit, second image generation circuit, position control circuit, and output control circuit (control circuit) that constitute the arithmetic processing unit or the like of a computer. Furthermore, the communication unit 121, storage unit 122, and display unit 123 (output unit) of the imaging device 10 may be implemented as a communication function, storage function, and display function (output function) that includes the functions of, for example, an arithmetic processing unit. Also, the communication unit 121, storage unit 122, and display unit 123 (output unit) of the imaging device 10 may be implemented as a communication circuit, storage circuit, and display circuit (output circuit) by being composed of, for example, an integrated circuit. Furthermore, the communication unit 121, storage unit 122, and display unit 123 (output unit) of the imaging device 10 may be configured as a communication device, storage device, and display device (output device) by being composed of, for example, multiple devices.

[0079] The imaging device 10 can be configured to combine one or any multiple of the above-described parts. In this disclosure, the term "information" is used, but the term "information" can be replaced with "data," and the term "data" can be replaced with "information."

[0080] This invention makes it possible to capture the internal structure more clearly than ever before, and to detect small defects that were previously undetectable.

[0081] As stated above, the present invention naturally includes various embodiments and the like that are not described herein. Therefore, the technical scope of the present invention is determined solely by the inventive features relating to the claims that are reasonable based on the above description. [Explanation of Symbols]

[0082] 10 Imaging device 101 Radiation source 102 Detectors 103 Object 104 Depth measuring instrument 105 Processing Unit 111 Radiation Source Control Unit 112 Acquisition Department 113 First Image Generation Unit 114 Second Image Generation Unit 115 Position control unit 116 Output Control Unit 121 Communications Department 122 Storage section 123 Display section 401 Transparent Image 402, 403 area 404 Dashed line

Claims

1. Radiation source and A detector for radiation emitted from the aforementioned radiation source, A depth measuring instrument for measuring the depth of an object placed between the radiation source and the detector in the depth direction from the radiation source to the detector, An image processing unit generates an image that removes the blurring of the object's boundary by calculating the brightness of each pixel before the change, based on the linear relationship between the depth and the amount of change in brightness of each pixel, using the depth and the brightness of each pixel of each transmission image of the object generated by the detector at each of the depths, when the depth of the object is changed two or more times relative to the depth of the object from the radiation source toward the detector, and the brightness of each pixel of each transmission image of the object generated by the detector at each of the depths, and A photographic device equipped with the following features.

2. The image processing unit corrects for the non-uniformity of the radiation intensity at each position of the detector by dividing the brightness of each pixel of each transmitted image by the brightness of each pixel of the image generated by the detector when the object is not placed between the radiation source and the detector, and then the original brightness M ｔ A photographic apparatus according to claim 1, which calculates [a certain value].

3. The image processing unit, for each of the transmission images generated at each depth, enlarges or reduces each of the other transmission images except for the one transmission image to make the sizes of the transmission images the same, and then adjusts the original brightness M ｔ A photographic apparatus according to claim 1, which calculates [a certain value].

4. The imaging apparatus according to claim 1, further comprising a position control unit that changes the position of the object between the radiation source and the detector in the depth direction while keeping the distance between the radiation source and the detector constant in the depth direction.

5. The image processing unit determines the distance between the radiation source and the detector as L ０ The distance between the radiation source and the object at each of the aforementioned depths is defined as follows: the distance between the radiation source and the object on the side of the depth closer to the radiation source is defined as the first distance L1, and the distance between the radiation source and the object on the side of the depth further from the radiation source is defined as the second distance L2; and the brightness of each desired pixel in the transmission image when the object is located at the first distance and the second distance is defined as M １ , and M ２ Therefore, the brightness M before the change in the desired pixel can be calculated using the following formula. ｔ Calculate [Math 1] The imaging apparatus according to claim 1.

6. A computer capable of communicating with a radiation source and a detector for radiation emitted from the radiation source, A depth measurement step of measuring the depth of an object placed between the radiation source and the detector in the depth direction from the radiation source to the detector, Image processing step to generate an image that removes the blurring of the object's boundary by calculating the brightness of each pixel before the change, based on the linear relationship between the depth and the amount of change in brightness of each pixel, using the depth at which the depth of the object is changed two or more times relative to the depth of the object from the radiation source toward the detector, and the brightness of each pixel of the transmission image of the object generated by the detector at each of the depths, A shooting method that includes the following features.

7. A computer capable of communicating with a radiation source and a detector for radiation emitted from the radiation source, A depth measurement function that measures the depth of an object placed between the radiation source and the detector in the depth direction from the radiation source to the detector, An image processing function that generates an image that removes the blurring of the object's boundaries by calculating the brightness of each pixel before the change, based on the linear relationship between the depth and the amount of change in brightness of each pixel, using the depth at which the depth of the object is changed two or more times relative to the depth of the object from the radiation source toward the detector, and the brightness of each pixel in the transmission image of the object generated by the detector at each of the depths, and A shooting program that makes this a reality.

Images