JP6281640B2 - X-ray apparatus, image forming method, structure manufacturing method, and structure manufacturing system - Google Patents

Description

  The present invention relates to an X-ray apparatus, an image forming method, a structure manufacturing method, and a structure manufacturing system.

  For example, an X-ray apparatus is known as a device that acquires information on the inside of a measurement object and / or information on the surface of the measurement object in a nondestructive manner. An X-ray apparatus is disclosed, for example, in Patent Document 1 below.

US Patent Application No. 14 / 221,319

  In the X-ray apparatus, for example, if a false image is generated in an image obtained by reconstruction, the detection accuracy may decrease as a result.

  An object of an aspect of the present invention is to provide an X-ray apparatus, an image forming method, a structure manufacturing method, and a structure manufacturing system that can suppress a decrease in detection accuracy.

According to an aspect of the present invention, an X-ray source that emits X-rays, a detector that detects X-rays emitted from the X-ray source, and a measured object between the X-ray sources in the detector region Filter correction processing by the filter back projection method is performed on the first projection data obtained in the first region where the object is present and the second projection data obtained in the second region where the object to be measured is not between the X-ray source and the object. A processing unit that performs a correction process to increase the value of the first projection data after the filter correction process and decrease the value of the second projection data after the filter correction process, and reconstructs the image. Is detected in the first region when it is assumed that the X-ray photons are scattered by the object to be measured and the amount of photons detected in the first region is not scattered by the object to be measured. An X-ray apparatus is provided that performs correction processing based on a correction coefficient corresponding to a ratio to the photon amount. According to an aspect of the present invention, an X-ray source that emits X-rays, a detector that detects X-rays emitted from the X-ray source, and a measured object between the X-ray sources in the detector region Filter correction processing by the filter back projection method is performed on the first projection data obtained in the first region where the object is present and the second projection data obtained in the second region where the object to be measured is not between the X-ray source and the object. A processing unit that performs a correction process to increase the value of the first projection data after the filter correction process and decrease the value of the second projection data after the filter correction process, and reconstructs the image. Provides an X-ray apparatus that performs correction processing using information on the energy spectrum of X-rays and information on the composition of the object to be measured. According to an aspect of the present invention, an X-ray source that emits X-rays, a detector that detects X-rays emitted from the X-ray source, and a measured object between the X-ray sources in the detector region Filter correction processing by the filter back projection method is performed on the first projection data obtained in the first region where the object is present and the second projection data obtained in the second region where the object to be measured is not between the X-ray source and the object. A processing unit that performs a correction process to increase the value of the first projection data after the filter correction process and decrease the value of the second projection data after the filter correction process, and reconstructs the image. Provides an X-ray apparatus that performs correction processing by estimating a state in which X-rays are not scattered by the object to be measured. According to an aspect of the present invention, there is provided an image forming method for forming an image by detecting a signal from an object to be measured by a detector, wherein the X-ray emitted from an X-ray source emitting X-rays is detected by the detector. Using the information of the X-ray energy spectrum and the composition of the object to be measured, in the first region where the object to be measured is located between the detector and the X-ray source. Filter correction processing by the filter back projection method is performed on the first projection data obtained and the second projection data obtained in the second region where there is no object to be measured between the X-ray source and the second projection data after the filter correction processing. Image formation including performing correction processing to increase the value of one projection data and decrease the value of second projection data after filter correction processing, and reconstructing an image based on the data after correction processing A method is provided. According to the first aspect of the present invention, an X-ray source that emits X-rays, a detector that detects X-rays emitted from the X-ray source, and an X-ray source in a region of the detector. Correction processing for increasing the value of the first projection data obtained in the first area with the object to be measured and decreasing the value of the second projection data obtained in the second area without the object to be measured with the X-ray source And a processing unit for reconstructing an image.

  According to a second aspect of the present invention, there is provided an image forming method for forming an image by detecting a signal from an object to be measured by a detector, and receiving the signal from the object to be measured in a region of the detector. Performing correction processing to increase the value of the first signal obtained in the first region and decrease the value of the second signal obtained in the second region that does not receive a signal from the object to be measured; Reconstructing an image based on the data.

  According to the third aspect of the present invention, the design process for creating the design information related to the shape of the structure, the molding process for creating the structure based on the design information, and the shape of the produced structure as the X-ray apparatus. There is provided a manufacturing method of a structure having a step of measuring using a step and an inspection step of comparing shape information obtained in the measuring step with design information.

  According to the fourth aspect of the present invention, the design apparatus for producing design information relating to the shape of the structure, the molding apparatus for producing the structure based on the design information, and the X for measuring the shape of the produced structure A structure manufacturing system is provided that includes a line device and an inspection device that compares design information with shape information related to the shape of the structure obtained by the X-ray device.

  According to the aspect of the present invention, it is possible to suppress a decrease in detection accuracy.

It is a figure which shows an example of the whole structure of the X-ray apparatus which concerns on embodiment of this invention. It is a figure for demonstrating the principle of a back projection method and a filter correction | amendment back projection method. It is a figure which shows distribution of the scattering component of X-ray | X_line. It is a figure which shows the projection data after a filter correction process, and the projection data after a correction process. 3 is a flowchart for explaining an image forming method according to an embodiment of the present invention. It is a follow chart which shows the correction coefficient calculation process of 1st Embodiment. It is a figure which shows the energy spectrum of the X-rays inject | emitted from the X-ray source. It is a wave form diagram which shows the characteristic information of the absorption cross section of aluminum, and a scattering cross section. It is a figure which shows the state from which the distance which an X-ray passes the to-be-measured object according to the projection angle of the X-ray with respect to to-be-measured object is changed. It is a follow chart which shows the correction coefficient calculation process of 2nd Embodiment. It is a wave form diagram which shows the mean free path of the photon of the X-ray which passes in the inside of aluminum. It is a follow chart which shows the correction coefficient calculation process of 3rd Embodiment. It is a block diagram which shows the structure of a structure manufacturing system. It is a flowchart which shows the flow of the process by a structure manufacturing system.

  Embodiments of the present invention will be described below with reference to the drawings. However, the present invention is not limited to this. Further, in the drawings, in order to describe the embodiment, there is a case where the scale is appropriately changed and expressed by partially enlarging or emphasizing the description. In the following description, an XYZ orthogonal coordinate system is set, and the positional relationship of each part will be described with reference to this XYZ orthogonal coordinate system. A predetermined direction in the horizontal plane is defined as the Z-axis direction, a direction orthogonal to the Z-axis direction in the horizontal plane is defined as the X-axis direction, and a direction orthogonal to each of the Z-axis direction and the X-axis direction (that is, the vertical direction) is defined as the Y-axis direction. Further, the rotation (inclination) directions around the X axis, Y axis, and Z axis are the θX, θY, and θZ directions, respectively.

<First Embodiment>
FIG. 1 is a diagram showing an example of the overall configuration of an X-ray apparatus 1 according to an embodiment of the present invention. The X-ray apparatus 1 according to the embodiment of the present invention irradiates a measurement object (test object) S with X-ray XL, and detects transmitted X-rays transmitted through the measurement object S. The X-ray apparatus 1 irradiates the measurement object S with X-rays, detects the X-rays that have passed through the measurement object S, and stores information (for example, internal structure) inside the measurement object S. Includes X-ray CT inspection equipment acquired by destruction. In the present embodiment, the device under test S includes industrial parts such as mechanical parts and electronic parts. The X-ray CT inspection apparatus includes an industrial X-ray CT inspection apparatus that irradiates industrial parts with X-rays and inspects the industrial parts.

  The X-ray apparatus 1 irradiates the measurement object S with X-ray XL and detects X-rays transmitted through the measurement object S. X-rays are electromagnetic waves having a wavelength of about 1 pm to 30 nm, for example. The X-ray includes at least one of an ultra-soft X-ray of about 50 eV, a soft X-ray of about 0.1 to 2 KeV, an X-ray of about 2 to 20 Kev, and a hard X-ray of about 20 to 100 KeV.

  As shown in FIG. 1, the X-ray apparatus 1 is emitted from an X-ray source 2 that emits X-ray XL, a stage apparatus 3 that can move while holding the object to be measured S, and an X-ray source 2 that emits a stage. A detector 4 that detects at least a part of the X-ray XL that has passed through the measurement object S held by the apparatus 3 and a control device 5 that controls the operation of the entire X-ray apparatus 1 are provided. Although not shown in FIG. 1, the X-ray apparatus 1 has an internal space formed by a chamber member. The X-ray source 2, the stage device 3, and the detector 4 are disposed in the internal space. Further, in the example shown in FIG. 1, the DUT S is a cylindrical object.

  The X-ray source 2 irradiates the measurement object S with X-ray XL. The X-ray source 2 can adjust the intensity of X-rays applied to the measurement object S based on the X-ray absorption characteristics of the measurement object S. The X-ray source 2 includes a point X-ray source, and irradiates the object S to be measured with conical X-rays (so-called cone beam). The shape of the X-ray XL emitted from the X-ray source 2 is not limited to a conical shape, and may be a fan-shaped X-ray (so-called fan beam), for example. Further, for example, a linear X-ray (so-called pencil beam) may be used.

  The X-ray source 2 is installed so as to be long in the Y direction. An exit port 2a is formed at the tip of the X-ray source 2 on the + Y side. The injection port 2a opens toward the object S to be measured. The inside of the injection port 2a may be a gap, or may be closed with a material having high X-ray XL permeability. X-ray XL is emitted in the + Z direction from the emission port 2a. At least a part of the X-ray XL emitted from the X-ray source 2 travels in the + Z direction.

  The stage device 3 includes a stage 9 and a stage drive mechanism (not shown). The stage 9 is provided so as to be movable while holding the object to be measured S. The stage 9 has a holding unit (not shown) that holds the measurement object S. The stage 9 can be translated in, for example, the X direction, the Y direction, and the Z direction by a stage drive mechanism (not shown), and can be rotated in the θY direction. Note that the position of the stage 9 (position of the object to be measured S) by the stage driving mechanism is controlled by the control device 5. The position of the stage 9 includes one or both of a translation position in at least one of the X direction, the Y direction, and the Z direction and a rotational position in at least one direction of the θX direction, the θY direction, and the θZ direction.

  The detector 4 is disposed on the opposite side of the X-ray source 2 across the stage 9 (measurement object S). The detector 4 is arranged on the + Z side with respect to the stage 9. For example, the detector 4 is fixed at a predetermined position of the X-ray apparatus 1, but may be movable. The detector 4 includes a plurality of scintillator units 34 and a plurality of light receiving units 35. The detector 4 has a planar surface 4A formed in parallel to the XY plane. The surface A is a surface on which the X-ray XL from the X-ray source 2 is incident, and is directed in the −Z direction. The surface 4 </ b> A is disposed to face the measurement object S held on the stage 9. The X-ray XL from the X-ray source 2 including the transmitted X-ray transmitted through the measurement object S is incident on the surface 4A.

  The plurality of scintillator portions 34 are arranged in an array in the XY plane. Each of the plurality of scintillator units 34 includes a scintillation substance that generates light by being irradiated with X-rays. Each of the plurality of scintillator units 34 generates light corresponding to the intensity of the X-ray XL incident on the surface 4A.

  The detector 4 has a plurality of light receiving portions 35 so as to be connected to each of the plurality of scintillator portions 34. Each of the plurality of light receiving portions 35 includes a photomultiplier tube. The photomultiplier tube includes a phototube that converts light energy into electrical energy by a photoelectric effect. Each of the plurality of light receiving units 35 receives and amplifies the light generated in the scintillator unit 34, and converts the amplified light into an electrical signal. The detector 4 transmits a signal corresponding to the intensity of the X-rays detected by each of the plurality of elements (scintillator unit 34 and light receiving unit 35) to the control device 5. A signal from each element obtained by the detector 4 is referred to as projection data.

  The control device 5 comprehensively controls the operations of the X-ray source 2, the stage device 3 (stage 9), and the detector 4. That is, the control device 5 outputs a control signal to the X-ray source 2 and causes the X-ray source 2 to emit the X-ray XL toward the object S to be measured. Further, the control device 5 outputs a control signal to the stage device 3 and moves (changes) the position of the object S to be measured by the stage device 3 (stage drive mechanism). Further, the control device 5 outputs a control signal to the detector 4 to cause the detector 4 to acquire projection data.

  In addition, the control device 5 includes an acquisition unit 51, a processing unit 52, and a storage unit 53. The acquisition unit 51 receives and acquires the projection data at each position of the measurement object S transmitted from the detector 4. Further, the acquisition unit 51 receives and acquires spectrum information (see FIG. 7 described later) regarding the energy spectrum of the X-ray XL emitted from the X-ray source 2 stored in advance in the storage unit 53. Further, the acquisition unit 51 receives and acquires product information related to the measurement object S (for example, industrial parts) transmitted from an external device (for example, a computer provided separately from the X-ray apparatus 1). The product information includes shape information related to the shape of the object to be measured S and composition information of a substance constituting the object to be measured S. The shape information is information representing the three-dimensional shape of the object to be measured S (for example, an industrial part and a part constituting the industrial part) by coordinate data. The composition information of the substance is information that represents the type of substance (for example, iron, aluminum, plastic, etc.) that constitutes the object to be measured S (for example, an industrial part and a part that constitutes the industrial part). When the first part of the object to be measured S is iron and the second part is aluminum, the composition information of the substance includes the coordinates of the first part and the information of the substance (iron), and the second part. Contains coordinates and material (aluminum) information.

  The processing unit 52 performs a filter correction process on the projection data acquired by the acquisition unit 51, and performs a correction process on the projection data after the filter correction process. And the process part 52 reconstructs the image of the to-be-measured object S based on the data after a correction process. The filter correction process is a process for correcting projection data using a filter having a predetermined frequency characteristic. Details of the filter correction processing will be described later (see step S2 in FIGS. 2, 4, and 5). Further, the correction process assumes that the projection data obtained by the detector 4 (projection data after the filter correction process) is assumed that the X-ray XL irradiated from the X-ray source 2 is not scattered by the measurement object S. This is a process for correcting projection data. In this correction process, the processing unit 52 calculates the correction coefficient γ using the spectrum information regarding the energy spectrum of the X-ray XL emitted from the X-ray source 2 and the composition information of the substance constituting the DUT S, This is performed by multiplying the calculated correction coefficient γ by the projection data after the filter correction processing (see steps S3, S4, FIG. 6, etc. in FIGS. 4 and 5). Details of this correction processing will also be described later. Note that the processing unit 52 can form both a two-dimensional image and a three-dimensional image.

  The storage unit 53 has the projection data of each position of the measurement object S acquired by the acquisition unit 51, the projection data of each position of the measurement object S after the filter correction processing is performed by the processing unit 52, and the processing unit 52. The projection data at each position of the object to be measured S after the correction process is performed is stored. The storage unit 53 stores the image data of the measurement object S reconstructed by the processing unit 52. Further, the storage unit 53 stores spectrum information related to the energy spectrum of the X-ray XL emitted from the X-ray source 2. The spectrum information is information measured in advance by a spectrum measuring instrument or the like. In addition, the storage unit 53 stores product information related to the measurement object S acquired by the acquisition unit 51. Further, the storage unit 53 stores characteristic information (see FIG. 8) for each substance of the absorption cross section and the scattering cross section. Examples of the substance include iron, aluminum, and plastic. In addition, in the correction described later, when a sufficient difference is not recognized, the characteristic information of a predetermined substance may be substituted with the characteristic information of another substance. For example, when the iron characteristic information and the aluminum characteristic information can be substituted, the aluminum characteristic information may be used instead of the iron characteristic information. Further, the characteristic information of iron and the characteristic information of aluminum may be substituted with other characteristic information. In this case, characteristic information created by averaging iron characteristic information and aluminum characteristic information may be used. Therefore, the stored information may be metal characteristic information and non-metal characteristic information. Of course, you may have all the characteristic information for every substance. These pieces of characteristic information may be information created by an apparatus that measures the object to be measured S, or may be information created by an apparatus different from the apparatus that measures the object to be measured S. Also, information obtained by calculating characteristic information may be used.

  Next, an example of the operation of the X-ray apparatus 1 will be described. In the detection of the measurement object S, the measurement object S held on the stage 9 of the stage device 3 is disposed between the X-ray source 2 and the detector 4. The control device 5 outputs a control signal to the stage device 3 and adjusts the position of the stage 9 holding the object S to be measured. Then, the control device 5 outputs a control signal to the X-ray source 2 to emit the X-ray XL from the X-ray source 2. Specifically, when a current flows through the filament of the X-ray source 2, the filament is heated and electrons are emitted from the filament. The electrons emitted from the filament are accelerated by the acceleration voltage and irradiated onto the target. Thereby, X-rays are generated from the target.

  At least a part of the X-ray XL generated by the X-ray source 2 is applied to the object S to be measured. When the measurement object S is irradiated with the X-ray XL, at least a part of the X-ray XL irradiated to the measurement object S passes through the measurement object S. The transmitted X-rays that have passed through the measurement object S enter the surface 4A of the detector 4. The detector 4 detects transmitted X-rays that have passed through the measurement object S. The detector 4 detects an image (projected image, transmitted image) of the measured object S obtained based on the transmitted X-rays transmitted through the measured object S. The detector 4 outputs projection data representing an image of the measurement object S to the control device 5.

  The control device 5 irradiates the measurement object S with the X-ray XL while rotating the stage 9 holding the measurement object S in the θY direction. The control device 5 changes the irradiation region of the X-ray XL from the X-ray source 2 in the measurement object S by changing the position of the measurement object S with respect to the X-ray source 2. Transmitted X-rays that have passed through the DUT at each position (each rotation angle) of the stage 9 are detected by the detector 4. The detector 4 acquires projection data representing an image of the measurement object S at each position. The control device 5 acquires projection data from the detector 4 and performs predetermined processing (filter correction processing and correction processing) on the acquired projection data. And the control apparatus 5 calculates the image of the internal structure of the to-be-measured object S based on the projection data which performed the predetermined process. In this embodiment, reconstruction is performed using an image acquired by rotating the stage 9 holding the object S to be rotated 360 ° in the θY direction. However, an image used for reconstruction is an image acquired by rotating 360 °. Not limited to. For example, the image used for reconstruction may be an image obtained by rotating 180 °. Of course, the image used for reconstruction may be an image obtained by rotating 720 °. The image used for reconstruction is not limited to this, and any image may be used as long as it can be reconstructed with the acquired image and inspected with the reconstructed image.

  Next, the principle of the back projection method and the filter-corrected back projection method, which are methods for reconstructing a tomographic image of the object S, will be described with reference to FIG.

  FIG. 2 is a diagram for explaining the principle of the back projection method and the filtered back projection method. First, the principle of the back projection method will be described. In the example shown in FIGS. 2A and 2B, the DUT 110 having a high X-ray absorption coefficient (for example, columnar iron) is placed in the measurement region 100. The measurement area 100 corresponds to, for example, an area where the measurement object S can be arranged on the stage 9 shown in FIG. 1, and is an arbitrary area between the X-ray source 2 and the detector 4 including the arrangement area of the measurement object S. Is set in the area.

  When the X-ray source 2 emits X-ray XL, the detector 4 acquires projection data representing an image of the object 110 to be measured. Projection data d1 shown in FIG. 2A indicates data detected by one line element in the X direction in the detector 4, for example. This projection data d1 has an attenuation peak at a position in the X direction corresponding to the position of the DUT 110. The X-ray XL is absorbed by the interaction between the X-ray XL from the X-ray source 2 and the DUT 110. Further, the X-ray XL passes through the device under test 100 without interacting with some of the X-rays XL and the device under test 100. This projection data d1 indicates that the X-ray XL is attenuated by the DUT 110 at the peak position, and the X-ray XL is not attenuated (or hardly attenuated) at other positions. The control device 5 acquires the projection data d1 obtained by the detector 4. And the control apparatus 5 calculated | required projection to the storage area 200 shown in FIG.2 (b) corresponding to the reconstruction screen provided in the memory | storage part 53 with the numerical value proportional to the height of the peak of projection data d1. Distribute equally in the same direction as the direction (Z direction in the example shown in FIG. 1). Such processing is called back projection. Specifically, the control device 5 sets the numerical value proportional to the peak height of the projection data d1 in the partial area m1 of the storage area 200 (the longitudinal direction is the direction in which the projection is obtained as shown in FIG. 2B). , An area having a width corresponding to the peak width) is equally allocated to each pixel.

  When the projection of one X-ray XL is completed, the stage 9 rotates in the θY direction by a certain angle, and then the X-ray source 2 emits the X-ray XL. Thereby, the detector 4 acquires the projection data d2 shown to Fig.2 (a). In FIG. 2A, the X-ray source 2 and the detector 4 are shown moving relative to the stage 9 in the θY direction. The control device 5 assigns a numerical value proportional to the peak height of the projection data d2 acquired by the detector 4 to the partial area m2 of the storage area 200. Further, after the stage 9 rotates in the θY direction by a certain angle, the X-ray source 2 irradiates the X-ray XL. Thereby, the detector 4 acquires the projection data d3 shown to Fig.2 (a). The control device 5 assigns a numerical value proportional to the peak height of the projection data d3 acquired by the detector 4 to the partial area m3 of the storage area 200. Such rotation, projection, and back projection operations are performed from multiple directions.

  When the numerical values back-projected from multiple directions are superimposed, the position of the object 110 to be measured becomes high density in the storage area 200, and a spoke-like pattern centered on that position appears. This image is an image reconstructed by the back projection method. The position of the object to be measured 110 is a high-density place in the center of the spoke-like pattern, but a spoke-like false image is generated around it. This false image has a property of decreasing in inverse proportion to the distance from the center position of high density.

  Next, the principle of the filtered back projection method will be described. The filtered backprojection method aims to remove false images generated by the backprojection method. In the backprojection method, a numerical value that is directly proportional to the obtained projection size (peak height) is backprojected. In the filtered backprojection method, however, a certain kind of conversion (this conversion is applied to the projection data). Back projection is performed after the filter correction processing.

  As described above, the detector 104 acquires projection data d1, d2, and d3 corresponding to the projection direction. The control device performs processing (filter correction processing) on each of these projection data d1, d2, and d3 with a filter having a predetermined characteristic such as a Ramp filter, for example, to obtain a filter as shown in FIG. The projection data d11, d12, d13 after the correction process are calculated. An example of the Ramp filter is shown in FIG. The calculation used for the filter correction process is performed by superposition integration, and the image quality of the reconstructed tomographic image changes depending on the frequency characteristics of the filter. As shown in FIG. 2A, the projection data after the filter correction processing is expressed as negative when the portion where X-rays are attenuated is positive, and 0 as the distance from the portion where X-rays are attenuated. A function that approaches

  FIG. 2B is a diagram showing backprojection using projection data after the filter correction processing. It is a figure reconfigure | reconstructed by the projection data which carried out the filter correction process in the predetermined cross section. In the projection data d11, d12, and d13 after the filter correction processing, the portion corresponding to the DUT 110, which is a portion where X-rays are attenuated, is positive, and the other portions are negative. Therefore, by superimposing the post-projection data, the positive value increases and the value of the portion corresponding to the DUT 110 increases. On the other hand, since the other parts are negative, the intersections of the positive parts of the center overlap and become positive values, but the positive parts and surrounding negative parts cancel each other except for that point. It becomes almost zero. Therefore, the positive value of the part corresponding to the DUT 100 increases and remains as a high concentration part. That is, the portion that attenuates X-rays remains as a high-concentration substance, and the cross section of the DUT 110 is restored.

  Next, the influence on the projection data by the scattered component of the X-ray XL in the measurement object S will be described with reference to FIG.

  FIG. 3 is a diagram showing the distribution of scattered components of the X-ray XL. As shown in FIG. 3, a part of the X-ray XL emitted from the X-ray source 2 in the + Z direction (hereinafter referred to as X-ray XL1) reaches the measurement object S and is emitted from the X-ray source 2. Another part of the X-ray XL (hereinafter referred to as X-ray XL2) enters the surface 4A of the detector 4 without passing through the object S to be measured. Here, in the region of the surface 4A of the detector 4, a region where the object S is between the X-ray source 2 is referred to as a first region A1, and the object S is between the X-ray source 2. The area that does not exist is referred to as a second area A2.

  When X-rays pass through a substance, photoelectric absorption due to the photoelectric effect due to the interaction between the X-ray and the substance, scattering due to the interaction between the X-ray and the substance, passage through the substance without causing an interaction, etc. Can be given. The photoelectric effect is that X-rays are absorbed by giving a part of the energy of incident X-ray photons to a substance. Scattering means that incident X-ray photons collide with a substance, give a part of energy to the substance, and incident photons are scattered. As the scattering, there is Compton scattering. In addition, Rayleigh scattering and the like can be given. Therefore, the X-ray XL1 (X-rays XL11 to XL14) that reaches the measurement object S is absorbed and scattered in the measurement object S. A certain X-ray XL11 out of the X-rays XL1 reaching the device under test S is absorbed in the device under test S. In addition, an X-ray XL12 among the X-rays XL1 is scattered in the object to be measured S and changes its traveling direction, and enters the first region A1 or the second region A2 of the surface 4A of the detector 4. Further, some X-ray XL13 of the X-ray XL1 is absorbed in the object to be measured S after being scattered in the object to be measured S. Further, a certain X-ray XL14 among the X-rays XL1 is incident on the first region A1 of the surface 4A of the detector 4 without being absorbed or scattered in the measured object S. That is, the X-ray XL incident on the detector 4 includes the X-ray XL12 that has been scattered by the measurement object S but has not been absorbed, and the X-ray XL14 that has not been scattered or absorbed by the measurement object S. It is.

  As shown in FIG. 3, the X-ray XL12 is scattered at various locations in the object S to be measured, and changes its course in various directions. Therefore, the scattering component detected by the detector 4 is a result of scattering in the object to be measured S as shown in FIG. A part of the scattered X-ray XL12 enters the second region A2 without entering the first region A1 of the surface 4A of the detector 4. In addition, the distribution of scattering components of the X-ray XL1 (that is, the distribution of photons of the X-ray XL12 after scattering) is determined by the shape of the object S, the material (type of substance) of the object S, the X-ray source 2 Depends on various parameters such as acceleration voltage.

  As described above, when the detector detects the scattered component at the object to be measured S, it is difficult to accurately estimate the attenuation amount of the object to be measured S. Moreover, it becomes difficult to accurately estimate the attenuation region of the measurement object S by detecting the scattered component in the measurement object S in this way. In addition, by detecting the scattering component on the measurement object S in this way, the contrast of the projection data of the projection image of the measurement object S is reduced. The contrast of the projection data is the difference between the portion detected by passing through the measurement object S and attenuated by X-rays and the portion detected without passing through the measurement object S and hardly attenuated with respect to the noise level. Is the ratio. When reconstruction is performed using such projection data, a false image is generated in a reconstructed image, for example, a tomographic image. If an image including a false image is used, the detection accuracy may be reduced.

  Therefore, in the present embodiment, the processing unit 52 of the control device 5 corrects X-ray scattering on the DUT S. In the present embodiment, the scattering due to the interaction between the measurement object S and the X-ray is estimated. Further, when it is assumed that there is no scattering due to the interaction between the measurement object S and the X-ray, it is assumed that the estimated scattered X-ray interacts with the measurement object and is absorbed in the measurement object S. The amount of X-rays absorbed by the measurement object S increases as compared with the case where there is scattering. In this embodiment, it is assumed that there is no scattering on the measurement object S, and correction processing for correcting projection data is performed.

  FIG. 4 is a diagram showing the projection data d10 after the filter correction process and the projection data d20 after the correction process. The processing unit 52 performs filter correction on the projection data obtained by the detector 4 using, for example, a Ramp filter (or Ram-Lak filter) as shown in FIG. As shown in FIG. 4B, the projection data d10 after the filter correction is such that the peak data d10a corresponding to the object S to be measured is positive and the other data d10b is negative, and as the distance from the peak increases. The waveform data is asymptotic to zero. In d10a, the device under test S is arranged between the X-ray generation region of the X-ray source 2 and the detector 4. For this reason, the peak corresponding to attenuation by the to-be-measured object S is detected. As for d10b, the to-be-measured object S is not arrange | positioned between the X-ray generation area | region of the X-ray source 2, and the detector 4. FIG.

  The processing unit 52 performs correction processing on the projection data d10 after filter correction. As described above, the correction process is a process of correcting the projection data d10 when X-rays are scattered by the measurement object S to the projection data d20 when it is assumed that the X-rays are not scattered by the measurement object S. is there. In the present embodiment, the processing unit 52 performs correction processing by multiplying the projection data d10 after filter correction by a correction coefficient γ as shown in FIG. Here, the correction coefficient γ includes the photon amount estimated to be detected in the first region A1 of the detector 4 when the photons of the X-ray XL1 are scattered by the measurement object S, and the photons of the X-ray XL1. When it is assumed that the object to be measured S is not scattered, the value is set in accordance with the ratio with the photon amount estimated to be detected in the first region A1 of the detector 4. This value is a positive value greater than 1. Details of how the processing unit 52 calculates the correction coefficient γ will be described later (see FIGS. 6 to 9).

  The first projection data d20a in the projection data d20 after the correction process (positive value data at the peak corresponding to the object S to be measured) is obtained by multiplying the first projection data d10a by the correction coefficient γ. . For this reason, as shown in FIG.4 (c), the 1st projection data d20a becomes a larger value than the 1st projection data d10a. Further, the second projection data d20b (negative value data of the portion corresponding to the periphery of the measurement object S) is also obtained by multiplying the second projection data d10b by the correction coefficient γ. For this reason, as shown in FIG. 4C, the absolute value of the second projection data d20b is larger than the absolute value of the second projection data d10b.

  By the way, when scattering occurs in the object to be measured S, an area corresponding to the object to be measured S (for example, the first area A1 in FIG. 3) or an area corresponding to the periphery of the object to be measured S (for example, the second area in FIG. 3). X-ray scattering components are incident on the area A2). Scattering components are included in the first projection data d10a and the second projection data d10b. This scattering component can cause a false image. The first projection data d20a and the second projection data d20b are data from which at least a part of the scattered component has been removed by the correction using the correction coefficient γ. That is, by reducing the value of the projection data corresponding to the periphery of the object S to be measured and increasing the value of the projection data corresponding to the object S to be measured, at least a part of the scattered component can be removed and X-rays can be removed. It is possible to take into account the increase in absorption in the case of handling as non-scattering.

  Next, an image forming method according to an embodiment of the present invention will be described with reference to FIGS.

  FIG. 5 is a flowchart for explaining the image forming method according to the embodiment of the present invention. In the processing shown in FIG. 5, first, the control device 5 causes the X-ray source 2 to emit X-ray XL toward the measurement object S, and the projection data representing the projection image of the measurement object S to the detector 4. Get it. And the acquisition part 51 of the control apparatus 5 acquires the projection data output from the detector 4 (step S1). Next, the processing unit 52 performs filter correction processing on the projection data acquired by the acquisition unit 51 using, for example, a Ramp filter (or Ram-Lak filter) as illustrated in FIG. S2). In addition, the processing unit 52 calculates a correction coefficient γ used in the correction process (step S3).

  FIG. 6 is a follow chart showing the correction coefficient calculation processing of the first embodiment. The correction coefficient calculation process (steps S31 to S34) illustrated in FIG. 6 corresponds to the process of step S3 illustrated in FIG. In the process illustrated in FIG. 6, the acquisition unit 51 acquires spectrum information related to the energy spectrum of the X-ray XL stored in the storage unit 53 (step S31). The processing unit 52 uses the spectrum information acquired by the acquisition unit 51 to store the X-ray XL energy region emitted from the X-ray source 2 when the X-ray apparatus 1 measures the measurement object S, and the X-rays. Recognize the energy spectrum in the XL energy region.

  FIG. 7 is a diagram showing an energy spectrum of the X-ray XL emitted from the X-ray source 2. In FIG. 7, the horizontal axis indicates the energy [keV] of the X-ray XL, and the vertical axis indicates the intensity of the X-ray XL. As described above, in the X-ray source 2, when a current flows through the filament, the filament is heated and electrons are emitted from the filament. Then, the X-ray source 2 accelerates electrons emitted from the filament with an acceleration voltage and irradiates the target. When the electrons collide with the target, two types of X-rays (specific X-rays and continuous X-rays shown in FIG. 7) are generated from the target.

  Holes are created by the repelling of the inner electrons of the atoms constituting the target by the accelerated electrons. X-rays corresponding to the energy difference of the electron orbit are emitted when the outer electrons transition to the holes. This X-ray is called intrinsic X-ray (or characteristic X-ray). The characteristic X-ray shows a spectrum specific to the constituent atoms of the target. In addition, X-rays are emitted when the trajectory of the accelerated electrons changes due to the interaction with the atoms in the target. Since this X-ray has a continuous wavelength distribution, it is called continuous X-ray.

  As shown in FIG. 7, intrinsic X-rays are generated in a narrow energy region (range), whereas continuous X-rays are generated over a wide energy region (range). In FIG. 7, only the energy up to 120 [keV] is shown as the energy spectrum of the X-ray XL, but in the measurement of the object S to be measured in the present embodiment, about 1 [keV] to about 225 [keV]. X-ray XL with energy up to] is used. That is, the X-ray source 2 in the present embodiment emits X-rays XL having energy of about 1 [keV] to about 225 [keV]. Based on the spectrum information, the processing unit 52 has an energy region in which the X-ray XL is about 1 [keV] to about 225 [keV], and the energy spectrum in the energy region of the X-ray XL is as shown in FIG. Recognize that the spectrum is The X-ray spectrum used for measurement may be data measured for each measurement, or stored X-ray spectrum data. Further, the stored X-ray spectrum may be obtained by measuring X-rays from an X-ray source used for measurement, or may be obtained by other X-ray sources.

  Returning to the description of FIG. 6, the acquisition unit 51 receives and acquires product information related to the device under test S transmitted from the external device. And the process part 52 acquires the composition information of the substance which comprises the to-be-measured object S from the product information regarding the to-be-measured object S acquired by the acquisition part 51 (step S32). As described above, the product information includes the composition information of the substance that represents the type of the substance that constitutes the measurement object S. In the following description, it is assumed that the object to be measured S is composed of a single type of substance (aluminum). Therefore, in step S32, the processing unit 52 acquires information indicating that the substance constituting the DUT S is aluminum as the substance composition information.

  Next, the processing unit 52 reads out the characteristic information of the cross-sectional area (absorption cross-sectional area, scattering cross-sectional area) of the substance from the storage unit 53 based on the composition information of the substance acquired in step S32. The processing unit 52 then absorbs the X-ray XL emitted from the X-ray source 2 (the X-ray XL energy specified by the spectrum information acquired in step S31), and the X-ray XL The correction coefficient γ is calculated using the scattering cross section with energy (step S33).

FIG. 8 is a spectrum diagram showing characteristic information of the absorption cross section and scattering cross section of aluminum (Al). In FIG. 8, the horizontal axis indicates the energy [keV] of the X-ray XL, and the vertical axis indicates the cross-sectional area [cm ² ] per 1 g of aluminum. It is the figure which plotted the cross-sectional area [cm < ² >] per 1g of aluminum in the energy of X-ray XL. In addition, both the horizontal axis and the vertical axis are expressed in logarithmic display. Here, the cross-sectional area represents the area interacting with the incident X-ray in terms of area. Therefore, when X-rays are incident on 1 g of aluminum, the X-rays are absorbed by the aluminum atoms or scattered by the aluminum atoms by the interaction in an area contributing to the interaction. The absorption cross-sectional area σ _PE corresponds to the (apparent) cross-sectional area in which photoelectric absorption occurs in the substance (aluminum) when the incident particle (incident photon) is regarded as a point. The scattering cross section σ _CS corresponds to the (apparent) cross sectional area in which Compton scattering occurs in the substance (aluminum) when the incident particle (incident photon) is regarded as a point.

As shown in FIG. 8, the absorption cross section σ _PE increases as the energy of the X-ray XL increases. It decreases from a value in the vicinity of E + 03 [cm ² ]. Further, as shown in FIG. 8, the scattering cross section σ _CS does not depend on the energy of the X-ray XL. E-02 [cm < ² >]-2. It does not change greatly at E-01 [cm ² ]. Further, as shown in FIG. 8, the absorption cross section σ _PE and the scattering cross section σ _CS intersect around about 50 [keV]. In this embodiment, photoelectric absorption and scattering are cited as the interaction between the X-ray XL and aluminum. In the low energy region of X-ray XL (region of about 1 [keV] to about 50 [keV]), the photoelectric absorption cross-section is larger than the cross-section of scattering as the interaction between X-ray XL and aluminum. large. Therefore, in the low energy region of X-ray XL, photoelectric absorption occurs with a higher probability than scattering. Therefore, the influence of scattering is small in the low energy region of the X-ray XL. On the other hand, in the high energy region of X-ray XL (region of about 50 [keV] or more), the cross-sectional area of scattering is larger than the cross-sectional area of photoelectric absorption as an interaction between X-ray XL and aluminum. Therefore, the influence of photoelectric absorption is small in the high energy region of the X-ray XL. Therefore, in the high energy region of X-ray XL, Compton scattering occurs with a higher probability than photoelectric absorption.

  In FIG. 8, Compton scattering is illustrated as the scattering, but the scattering to be studied is not limited to this. For example, Rayleigh scattering may be used. Further, both Compton scattering and Rayleigh scattering may be used.

The processing unit 52 measures the value of the object S to be measured by integrating the value obtained by integrating the absorption cross section σ _PE of aluminum in the energy region of the X-ray XL when the object S is measured and the scattering cross section σ _CS of aluminum. The correction coefficient γ is calculated based on the value integrated in the energy region of the X-ray XL when performing. Specifically, the processing unit 52 calculates the correction coefficient γ based on the following equation (1).

In the above formula (1), E indicates the energy of the X-ray XL emitted from the X-ray source 2. Emax corresponds to the acceleration voltage of the electron beam irradiated to the target of the X-ray source used for measurement. In this embodiment, 225 [Kev] is used as Emax. Note that Emax may be calculated from the detection result of X-rays used for measurement. The numerator in the above formula (1) is a value obtained by integrating the absorption cross section σ _PE (E) of aluminum at the energy of X-ray XL in the energy region (0 to 225 [keV]) of X-ray XL. The denominator in the above formula (1) is obtained by integrating the absorption cross section σ _PE (E) of aluminum in the energy of X-ray XL in the energy region (0 to 225 [keV]) of X-ray XL. It is a value obtained by subtracting a value obtained by integrating the scattering cross section σ _CS (E) of aluminum at the energy of the line XL in the energy region (0 to 225 [keV]) of the X-ray XL. From the above equation (1), the correction coefficient γ is calculated as a positive value larger than 1.

  Note that the maximum energy of the X-ray XL irradiated is estimated from the acceleration voltage of the electron beam irradiated to the target of the X-ray XL to be used, and each cross-sectional area up to the maximum energy is uniformly integrated to obtain a correction coefficient. However, the present invention is not limited to this. For example, the cross-sectional area ratio used for integration may be changed from the intensity ratio of each energy in the irradiated X-ray XL, and integration may be performed using the changed cross-sectional area. Alternatively, the correction coefficient γ may be calculated using the cross-sectional area of scattering and absorption at a predetermined energy. For example, the center value may be calculated from the energy distribution of the X-ray XL, the cross-sectional area of scattering and absorption at the calculated value may be calculated, and the correction coefficient γ may be obtained. The equation for calculating γ is not limited to the above equation (1). The following equation (2) may be used.

  As shown in Expression (2), the correction coefficient γ may be obtained using a value obtained by adding the cross-sectional area of photoelectric conversion and the cross-sectional area of scattering. In this embodiment, the cross-sectional area of photoelectric conversion and the cross-sectional area of scattering are used. However, the value used for calculating the correction coefficient γ is not limited to this. For example, the correction coefficient γ may be calculated using the absorption coefficient and the scattering coefficient. Any method can be used as long as the interaction between the X-ray and the substance can be estimated.

  Next, the processing unit 52 calculates the distance that the X-ray XL passes through the object to be measured S based on the shape information included in the product information acquired by the acquisition unit 51, and a correction coefficient according to the calculated distance. γ is changed (step S34).

  FIG. 9 is a diagram illustrating a state in which the distance that the X-ray XL passes through the measurement object S is changed according to the projection angle of the X-ray XL with respect to the measurement object S. In FIG. 9A, the X-ray source 2 irradiates the bottom surface of the cylindrical object to be measured S with the X-ray XL, and in FIG. 9B, the X-ray source 2 has the cylindrical shape to be measured. X-ray XL is irradiated to the side surface of the object S. In this way, the distance that the X-ray XL passes through the device under test S is changed according to the projection angle of the X-ray XL with respect to the device under test S. Further, when the distance that the X-ray XL passes through the measurement object S changes, the scattering amount of the X-ray XL in the measurement object S (the amount of photons scattered in the measurement object S) also changes. Therefore, the processing unit 52 changes the correction coefficient γ in accordance with the distance that the X-ray XL passes through the object S to be measured.

  In step S <b> 34, the processing unit 52 recognizes the three-dimensional shape of the measurement object S from the three-dimensional coordinate data based on the shape information included in the product information regarding the measurement object S. Further, the processing unit 52 recognizes a predetermined position of the X-ray source 2 (emission port 2a) from the three-dimensional coordinate data. Further, the processing unit 52 recognizes the projection angle of the X-ray XL with respect to the measurement object S based on the rotation angle of the stage 9 in the θY direction. Then, the processing unit 52 converts the X-ray XL into the object S based on the position of the X-ray source 2, the three-dimensional shape of the object S to be measured, and the projection angle of the X-ray XL with respect to the object S to be measured. The distance passing through is calculated. The X-ray XL emitted from the X-ray source 2 is a cone beam, and the distance through which the X-ray XL passes varies depending on the position of the measurement object S. Therefore, the processing unit 52 may calculate the average distance of the X-ray XL that passes through the measurement object S.

  The average distance of the X-ray XL passing through the DUT S may be calculated, and the weight of the DUT passing through the X-ray XL at each rotation angle may be calculated. In this case, the cross-sectional area with respect to the X-ray XL at the rotation angle changes. That is, by multiplying the cross-sectional area per gram by the actual weight, the cross-sectional area of the object S to be measured with respect to the X-ray XL can be calculated. The correction coefficient γ may be calculated using the calculated cross-sectional area, and the calculated correction coefficient γ may be used. That is, the correction coefficient γ may be calculated based on the distance that the X-ray XL passes through the DUT S. When the distance through which the measured object S passes with the rotation angle changes, the correction coefficient γ is changed with the rotation angle.

  Further, the average distance may be calculated for each rotation angle from the shape information of the measurement object S. Further, the average distance may be calculated for each rotation angle from the weight information of the measurement object S. Further, the correction coefficient γ may be changed for each rotation angle, or an average representative distance may be calculated from the average distance for each rotation angle, and the correction coefficient γ may be calculated from the calculated distance.

  Returning to the description of FIG. 5, the processing unit 52 performs a correction process on the projection data by multiplying the projection data that has been subjected to the filter correction process in step S <b> 2 by the correction coefficient γ calculated in step S <b> 3 ( Step S4). Thereby, the contrast of a projection image is raised. Next, the control device 5 moves (rotates) the stage 9 to change the position of the measurement object S with respect to the X-ray source 2 (projection direction of the X-ray XL from the X-ray source 2 to the measurement object S). Change (step S5). And the control apparatus 5 determines whether the to-be-measured object S was irradiated with the X-ray XL from all directions (step S6). When it is determined that the measurement object S is not irradiated with the X-ray XL from all directions (NO in step S6), the control device 5 executes the processes of steps S1 to S5. On the other hand, when the control device 5 determines that the object S to be measured is irradiated with the X-ray XL from all directions (YES in step S6), the processing unit 52 performs the correction process in step S4 at each position of the object S to be measured. An image is reconstructed based on the later projection data (step S7). Note that the image reconstructed in step S7 includes both a two-dimensional image and a three-dimensional image.

  As described above, in the first embodiment, the X-ray source 2 that emits the X-ray XL, the detector 4 that detects the X-ray XL emitted from the X-ray source 2, and the region of the detector 4 Among them, the value of the first projection data obtained in the first area A1 where the object to be measured S is present between the X-ray source 2 and the second area where the object S is not present between the X-ray source 2 and the X-ray source 2 is increased. A processing unit 52 that performs correction processing to reduce the value of the second projection data obtained in A2 and reconstructs the image. According to such a configuration, since correction processing is performed on the projection data, generation of a false image in an image obtained by reconstruction is suppressed, so that a decrease in detection accuracy is suppressed. Since the occurrence of a false image in an image obtained by reconstruction is suppressed, it is suppressed that a detection error is included when calculating the distance of one side of a predetermined portion of the image obtained by reconstruction. The

  In the first embodiment, the processing unit 52 performs the filter correction process on the first projection data and the second projection data obtained by the detector 4, and performs the correction process after the filter correction process. It is possible to obtain an image in which the false image of the image is suppressed. Therefore, not only an image obtained by reconstruction but also a projection image used for reconstruction can acquire an image in which a false image is suppressed.

  In the first embodiment, the processing unit 52 is configured to detect the amount of photons detected in the first region A1 when the photons of the X-ray XL are scattered by the device under test S, and the photons of the X-ray XL into the device under test. When it is assumed that the light is not scattered by S, the correction process is performed based on the correction coefficient γ according to the ratio to the photon amount detected in the first region A1. According to such a configuration, the processing unit 52 corrects the projection data based on the amount of photons absorbed in the measurement object S when it is assumed that the photons of the X-ray XL are not scattered by the measurement object S. be able to. Therefore, an image corresponding to the distribution of the X-ray absorption coefficient of the measurement object S can be acquired, and the quality of the reconstructed image can be improved.

  That is, in the energy region of the X-ray XL used for the measurement of the measurement object S, the influence of the X-ray XL scattering in the measurement object S becomes large. And a false image will arise in a reconstructed image by the scattering component of the X-ray XL in the to-be-measured object S. FIG. In this case, in order to suppress the influence of X-ray XL scattering in the DUT S, it is conceivable to correct the projection data by subtracting the scattering component from the projection data obtained by the detector 4. However, simply subtracting the scattering component from the projection data may reduce the amount of photons to be absorbed in the first region A1 of the surface 4A of the detector 4 and may not improve the contrast of the reconstructed image. On the other hand, the situation where the photons of the X-ray XL are assumed not to be scattered by the measurement object S is the optimum situation for obtaining the absorption coefficient image of the X-ray XL. Therefore, in the configuration of the first embodiment, the processing unit 52 assumes a projection corresponding to the amount of photons absorbed in the measurement object S when it is assumed that photons of the X-ray XL are not scattered by the measurement object S. Correct the data. If it is assumed that the X-ray XL is not scattered by the measurement object S, the amount of photons absorbed in the measurement object S increases, so the correction coefficient γ increases the amount of photons absorbed in the measurement object S. It is a value that compensates for the minute. Thereby, the contrast of the reconstructed image is improved.

  In the first embodiment, the processing unit 52 detects the amount of photons detected by the detector 4 when X-ray XL scatters in the measurement object S, and the X-ray XL scatters in the measurement object S. The correction coefficient γ is obtained from the photon amount detected by the detector 4 when it is assumed that it has not occurred. However, the detector 4 is not limited to detecting the photon amount, and may be detected as energy. Alternatively, the detector 4 may detect the spectrum and use the area of the spectrum to determine the correction coefficient γ.

  In the first embodiment, since the processing unit 52 performs the correction process by multiplying the first projection data and the second projection data by the correction coefficient γ, the correction process can be performed without performing enormous calculations. it can. Therefore, a reconstructed image can be acquired in a time substantially equal to the current reconstruction calculation time.

  In the first embodiment, the processing unit 52 uses the spectrum information related to the energy spectrum of the X-ray XL emitted from the X-ray source 2 and the composition information of the substance constituting the DUT S to correct the correction coefficient γ. Therefore, it is possible to calculate a correction coefficient according to the energy spectrum of the X-ray XL and the constituent material of the object S to be measured. In the first embodiment, the processing unit 52 calculates the correction coefficient γ using the absorption coefficient of the substance with the energy of X-ray XL and the scattering coefficient of the substance with the energy of X-ray. It is possible to calculate a correction coefficient γ that is consistent in terms of characteristics and qualities. The absorption cross section can be obtained from the absorption coefficient, and the scattering cross section can be obtained from the scattering coefficient.

  In the first embodiment, the processing unit 52 acquires the composition information of the substance constituting the device under test S based on the product information of the device under test S, so that the processing unit 52 configures the device under test S. Recognize the type of substance.

  In the first embodiment, the correction coefficient γ is set according to the distance that the X-ray XL passes through the device under test S, and therefore the amount of X-ray XL scattered in the device under test S (the device under test S). A correction coefficient can be set in accordance with the amount of photons scattered within. In the first embodiment, the processing unit 52 determines the distance that the X-ray XL passes through the measurement object S based on the shape of the measurement object S and the projection angle of the X-ray XL with respect to the measurement object S. Since it calculates, the correction coefficient according to the shape etc. of the to-be-measured object S can be acquired. Further, in the first embodiment, the processing unit 52 calculates the distance that the X-ray XL passes through the device under test S based on the shape information of the device under test S, so that the X-ray XL passes through the device under test S. The distance to be performed can be calculated easily and reliably.

Second Embodiment
In the first embodiment described above, the processing unit 52 calculates the correction coefficient γ using the absorption cross section (and the scattering cross section of the substance constituting the measurement object S. In contrast, in the second embodiment, the processing section 52 calculates the correction coefficient γ. The processing unit 52 calculates the correction coefficient γ based on the mean free path of the X-ray XL that passes through the substance constituting the object S to be measured.

  FIG. 10 is a follow chart showing a correction coefficient calculation process according to the second embodiment. Note that the correction coefficient calculation process of the second embodiment corresponds to the process of step S3 in FIG. Further, the processing in step S31 and step S32 in FIG. 10 is the same as the processing in step S31 and step S32 shown in FIG.

  In the process shown in FIG. 10, the processing unit 52 calculates a correction coefficient γ based on the mean free path of photons that are photoelectrically absorbed and the mean free path of photons that are Compton scattered (step S33A). Here, the mean free path means an expected value of the distance that can be moved before the photons of the X-ray XL are absorbed or scattered in the substance.

  FIG. 11 is a diagram showing the mean free path in scattering of photons of X-ray XL passing through aluminum. In FIG. 11, the horizontal axis indicates the energy [keV] of the X-ray XL, and the vertical axis indicates the mean free path [cm] of the photons of the X-ray XL. As shown in FIG. 11, in the region of about 20 [keV] or less of the X-ray XL, the value of the mean free path decreases rapidly as the energy of the X-ray XL increases. In the region of about 20 [keV] or more of the X-ray XL, the value of the mean free path gradually increases as the energy of the X-ray XL increases. FIG. 11 shows the mean free path due to Compton scattering of photons of X-ray XL passing through aluminum.

Assuming that the absorption cross section is σ _PE , the scattering cross section is σ _CS , and the density of atoms in the object to be measured S (aluminum) is n, the mean free path l _PE of photons photoelectrically absorbed by the object to be measured S is 1 / (n · σ _PE) and expressed, the mean free path _{l CS} of photons Compton scattered by the measurement object S is expressed as _{1 / (n · σ CS)} . Accordingly, the processing unit 52 calculates the correction coefficient γ using the mean free path l _PE and l _CS in the same manner as the principle of calculating the correction coefficient γ using the absorption cross section σ _PE and the scattering cross section σ _CS. can do. In other words, the processing unit 52 uses the mean free path l _PE and l _CS , the amount of photons absorbed photoelectrically per unit distance in the substance constituting the measurement object S, and the inside of the substance constituting the measurement object S Thus, the amount of Compton scattered per unit distance can be obtained. Then, the processing unit 52, based on the photon amount absorbed photoelectrically and the amount of photon scattered Compton, assumes that it is not Compton scattered in the measured object S, and the amount of energy absorbed photoelectrically in the measured object S. Can be calculated. When the processing unit 52 assumes that the Compton scattering in the measurement object S does not cause Compton scattering, the photon of the X-ray XL is scattered by the measurement object S based on the amount of photoelectrically absorbed energy in the measurement object S. Correction coefficient γ according to the ratio between the amount of energy detected in the first region A1 and the amount of energy detected in the first region A1 when it is assumed that the photons of the X-ray XL are not scattered by the measurement object S Is calculated.

  Thereafter, the processing unit 52 calculates the distance that the X-ray XL passes through the measurement object S based on the shape information included in the product information acquired by the acquisition unit 51, and the correction coefficient γ according to the calculated distance. Is changed (step S34). The method for calculating the distance that the X-ray XL passes through the DUT is the same as the method described in step S34 (see FIG. 6) of the first embodiment. In addition, as described in step S34 of the first embodiment, the absorption cross section and the scattering cross section change according to the distance that the X-ray XL passes through the DUT S. Accordingly, the processing unit 52 changes the value of the correction coefficient γ by multiplying the correction coefficient γ calculated in step S33A by a value corresponding to the distance that the X-ray XL passes through the device under test S.

  As described above, in the second embodiment, the processing unit 52 calculates the correction coefficient γ using the distance that can be moved until the photons of the X-ray XL are absorbed or scattered in the substance. It is possible to calculate a correction coefficient γ that is physically and qualitatively consistent.

<Third Embodiment>
In the first embodiment and the second embodiment described above, the acquisition unit 51 acquires the shape information of the measurement object S and the composition information of the substance constituting the measurement object S from the product information transmitted from the external device. It was. On the other hand, in the third embodiment, the processing unit 52 uses a three-dimensional image for analysis (shape information and composition of a substance reconstructed based on the first projection data and the second projection data before performing the correction process. The shape information of the object to be measured S and the composition information of the substance constituting the object to be measured S are acquired by analyzing the voxel data reconstructed to acquire the information.

  FIG. 12 is a follow chart illustrating a correction coefficient calculation process according to the third embodiment. Note that the correction coefficient calculation process of the third embodiment corresponds to the process of step S3 in FIG. Also, the processes in step S31, step S33, and step S34 in FIG. 12 are the same as the processes in step S31, step S33, and step S34 shown in FIG.

  In the process shown in FIG. 12, the processing unit 52 regenerates a three-dimensional image for analysis (voxel data) for acquiring shape information and composition information of a substance based on the projection data acquired in step S1 of FIG. Configure (step S32A). The three-dimensional image for analysis is reconstructed to acquire shape information and material composition information, and the contrast of the image may be low. Accordingly, the processing unit 52 performs the correction process to reconstruct the image as projection data for reconstructing the three-dimensional image for analysis (that is, when reconstructing the image in step S7 in FIG. 5). Is obtained from the detector 4 with a reduced data amount. That is, the processing unit 52 does not acquire projection data of all voxels obtained by the detector 4, but acquires data obtained by thinning out voxel data at predetermined intervals from the projection data obtained by the detector 4. .

  Further, the processing unit 52 performs a correction process on the intensity of the X-ray XL for acquiring a three-dimensional image for analysis, and reconstructs the image (that is, reconstructs the image in step S7 in FIG. 5). The intensity of the X-ray XL may be lower than that of the X-ray XL (the intensity of the X-ray XL when the projection data is acquired in step S1). In this case, power consumption in the X-ray source 2 when acquiring a three-dimensional image for analysis can be suppressed.

  Then, the processing unit 52 analyzes the three-dimensional image for analysis reconstructed in step S32A, so that the shape information indicating the three-dimensional shape of the measurement object S and the composition information of the substance constituting the measurement object S are obtained. Are acquired (step S32B). Specifically, the processing unit 52 recognizes the three-dimensional shape of the measurement object S as three-dimensional coordinate data based on the three-dimensional image for analysis. Further, the processing unit 52 recognizes the type of the substance constituting the device under test S (or a component constituting the device under test S) based on the luminance of each voxel in the three-dimensional image for analysis. For example, a portion where the voxel luminance is high (bright portion) in the analysis three-dimensional image indicates a portion of a substance having a low absorption rate, and a portion where the voxel luminance is low (dark portion) in the analysis three-dimensional image is The part of the substance with a high absorption rate is shown.

  Thereafter, the processing unit 52 calculates the correction coefficient γ based on the composition information of the substance constituting the DUT acquired in step S32B and the spectrum information of the X-ray XL acquired in step S31 (step S33). ). Further, the processing unit 52 calculates the distance that the X-ray XL passes through the device under test S based on the shape information of the device under test S acquired in step S32B, and changes the correction coefficient γ according to the calculated distance. (Step S34). Note that the processing unit 52 may execute the process of step S33A in FIG. 10 instead of the process of step S33.

  As described above, in the third embodiment, the processing unit 52 analyzes the three-dimensional image for analysis reconstructed based on the first projection data and the second projection data before performing the correction process. The composition information of the substance constituting the object to be measured S is acquired. According to such a configuration, even when the acquisition unit 51 cannot acquire the composition information of the substance constituting the DUT S, the composition information of the substance is acquired based on the three-dimensional image for analysis. The correction coefficient can be calculated based on the obtained composition information of the substance.

  In the third embodiment, the processing unit 52 performs first correction processing to reconstruct an image as first projection data and second projection data for reconstructing a three-dimensional image for analysis. The projection data and the second projection data are acquired from the detector 4 with a reduced data amount. According to such a configuration, it is possible to reduce the amount of data processing for obtaining a three-dimensional image for analysis, and it is possible to shorten the data processing time.

In the third embodiment, the processing unit 52 uses the intensity of the X-ray XL for reconstructing the three-dimensional image for analysis as compared to the intensity of the X-ray XL when performing the correction process to reconstruct the image. Reduce. According to such a configuration, power consumption in the X-ray source 2 when acquiring a three-dimensional image for analysis can be suppressed.
In addition, as a method of acquiring the composition information of the measurement substance S, for example, the composition information may be acquired using X-rays XL having different energies.

<Structure manufacturing system>
Next, a structure manufacturing system including the X-ray apparatus 1 described above will be described. FIG. 13 is a block diagram of the structure manufacturing system SYS. The structure manufacturing system SYS includes an X-ray device 1 as a measuring device, a molding device 720, a control device (inspection device) 730, and a repair device 740. In the present embodiment, the structure manufacturing system SYS creates a molded product such as an electronic part including an automobile door part, an engine part, a gear part, and a circuit board.

  The design device 710 creates design information related to the shape of the structure, and transmits the created design information to the molding device 720. In addition, the design device 710 stores the created design information in a coordinate storage unit 731 described later of the control device 730. Here, the design information is information indicating the coordinates of each position of the structure. The molding device 720 produces the structure based on the design information input from the design device 710. The molding process of the molding apparatus 720 includes casting, forging, cutting, or the like.

  The X-ray device 1 transmits information indicating the measured coordinates to the control device 730. The control device 730 includes a coordinate storage unit 731 and an inspection unit 732. As described above, design information is stored in the coordinate storage unit 731 by the design device 710. The inspection unit 732 reads design information from the coordinate storage unit 731. The inspection unit 732 creates information (shape information) indicating the created structure from information indicating the coordinates received from the X-ray apparatus 1. The inspection unit 732 compares information (shape information) indicating coordinates received from the X-ray apparatus 1 with design information read from the coordinate storage unit 731. The inspection unit 732 determines based on the comparison result whether or not the structure is molded according to the design information. In other words, the inspection unit 732 determines whether or not the created structure is a non-defective product. If the structure is not molded according to the design information, the inspection unit 732 determines whether or not the structure can be repaired. When repair is possible, the inspection unit 732 calculates a defective part and a repair amount based on the comparison result, and transmits information indicating the defective part and information indicating the repair amount to the repair device 740.

  The repair device 740 processes the defective portion of the structure based on the information indicating the defective portion received from the control device 730 and the information indicating the repair amount.

  FIG. 14 is a flowchart showing the flow of processing by the structure manufacturing system SYS. First, the design device 710 creates design information related to the shape of the structure (step S101). Next, the molding apparatus 720 produces the structure based on the design information (step S102). Next, the X-ray apparatus 1 measures coordinates relating to the shape of the structure (step S103). Next, the inspection unit 732 of the control device 730 inspects whether or not the structure is created according to the design information by comparing the shape information of the structure created from the X-ray device 1 and the design information. (Step S104).

  Next, the inspection unit 732 of the control device 730 determines whether or not the created structure is a non-defective product (Step S105). If the created structure is a non-defective product (step S106: YES), the structure manufacturing system SYS ends the process. On the other hand, when the created structure is not a non-defective product (step S106: NO), the inspection unit 732 of the control device 730 determines whether the created structure can be repaired (step S107).

  When the created structure can be repaired (step S107: YES), the repair device 740 performs reworking of the structure (step S108), and returns to the process of step S103. On the other hand, when the created structure cannot be repaired (step S107 YES), the structure manufacturing system SYS ends the process. Above, the process of this flowchart is complete | finished.

  As described above, since the X-ray apparatus 1 in the above embodiment can accurately measure the coordinates of the structure, the structure manufacturing system SYS can determine whether or not the created structure is a non-defective product. it can. In addition, the structure manufacturing system SYS can reconstruct and repair the structure when the structure is not good.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. Various modifications or improvements can be added to the above-described embodiment without departing from the spirit of the present invention. In addition, one or more of the requirements described in the above embodiments may be omitted. Such modifications, improvements, and omitted forms are also included in the technical scope of the present invention. In addition, the configurations of the above-described embodiments and modifications can be applied in appropriate combinations.

  In the first to third embodiments described above, the filter-corrected back projection method is used as an image reconstruction method. However, a back projection method or a successive approximation method may be used. The successive approximation method is described in, for example, US Patent Application Publication No. 2010/0220908.

  Further, the X-ray source 2 can adjust the intensity of X-rays applied to the measurement object S by changing the acceleration voltage according to the X-ray absorption characteristics of the measurement object S. In this case, the energy spectrum of the X-ray XL (specific X-ray, continuous X-ray) generated by the X-ray source 2 varies depending on the acceleration voltage. In such a configuration, the acquisition unit 51 acquires information indicating the acceleration voltage from the X-ray source 2 in step S <b> 31, and reads spectrum information corresponding to the acquired information from the storage unit 53. According to such a configuration, the processing unit 52 can calculate the correction coefficient γ based on the spectrum information corresponding to the acceleration voltage of the X-ray source 2.

  In addition, the composition information of the substance is information indicating the type of substance (for example, iron, aluminum, plastic, etc.) constituting the object to be measured S (for example, an industrial part and a part constituting the industrial part). Information indicating the type, component, density, etc. of the substance constituting the object to be measured S may be used. Moreover, the information which classified the kind of substance into the metal and the non-metal may be sufficient. In this case, a metal correction coefficient γ and a non-metal correction coefficient γ may be used. That is, the composition information of the substance may not be strictly used. In addition, for example, some living organisms such as living organisms or organs are composed of nonmetallic atoms such as oxygen and carbon, and therefore, the nonmetallic correction coefficient γ may be used as a representative. Of course, the correction coefficient γ for each atom may be calculated and used from the biological component information.

  Here, as the component of the substance, for example, when the substance includes iron or copper, information indicating the ratio of iron and the ratio of copper in the substance is assumed. As the density of the substance, information represented by the number of atoms of the substance contained per unit volume, the mass of the substance per unit volume, and the like is assumed. In this case, the processing unit 52 can calculate the correction coefficient γ with higher accuracy by deriving the absorption cross section and the scattering cross section based on information such as the type, component, and density of the substance.

  In the first embodiment described above, the processing unit 52 calculates the correction coefficient γ based on the formula (1) or the formula (2). However, the processing unit 52 may calculate the correction coefficient γ based on the following equation (3).

In the above equation (3), the processing unit 52 integrates the absorption cross section σ _PE and the scattering cross section σ _CS of the substance in the energy region of the X-ray XL when the measurement object S is measured, The correction coefficient γ is calculated based on the value obtained by integrating the scattering cross section σ _CS of the substance in the energy region of the X-ray XL when the measurement object S is measured.

  Further, the processing unit 52 uses a lookup table (hereinafter referred to as LUT) corresponding to a calculation formula (any one of the above formulas (1) to (3)) for calculating the correction coefficient γ. The correction coefficient γ may be obtained by referring to it. The LUT is obtained by obtaining in advance values that are calculation results of complicated calculation processing for various values, and storing these values in an array (table). A plurality of LUTs corresponding to spectrum information and material composition information are prepared in advance. The processing unit 52 selects an LUT corresponding to the composition information of the substance, and obtains a correction coefficient γ with reference to the selected LUT. As described above, the processing unit 52 obtains the correction coefficient γ by referring to the LUT, whereby the calculation process of a complicated calculation formula can be replaced with a reference process of a simple value (data), and the process efficiency can be improved. .

  By the way, in the above-described embodiment, in the correction processing after the filter correction processing, the first value (positive value) corresponding to the measured object S in the projection data is multiplied by the first correction coefficient, and the measured object. A second value (negative value) corresponding to the periphery of S is multiplied by a second correction coefficient. In the above-described embodiment, the first correction coefficient is the same as the second correction coefficient (correction coefficient γ). By making the first correction coefficient the same as the second correction coefficient, it is possible to reduce the load required for the calculation. In addition, when it is assumed that no scattering occurs, the increase in X-ray energy due to the loss of X-ray energy accompanying scattering is balanced with the decrease in X-ray energy due to increase in absorption. be able to.

  Note that the first correction coefficient may be different from the second correction coefficient. For example, the first correction coefficient may be larger than the second correction coefficient or smaller than the second correction coefficient. The first correction coefficient and the second correction coefficient may be set so as to satisfy a predetermined linear or non-linear relationship, or may be set independently of each other. In this way, by setting the first correction coefficient and the second correction coefficient to different values, it can be applied to a more complicated model.

  For example, a part (wide angle component) of X-rays scattered by the measurement object S may not enter the detector 4. That is, when it is assumed that scattering does not occur in the measurement object S, the increase in X-ray energy may not balance the decrease in energy due to absorption. In such a case, matching can be achieved by making the first correction coefficient larger than the second correction coefficient or smaller than the second correction coefficient.

  In the above-described embodiment, the correction coefficient γ is set using the absorption cross section and the scattering cross section or the mean free path, but may be set by other methods. For example, the correction coefficient may be set by comparing the result of measuring the shape of the measurement object S without performing correction by the correction coefficient γ with the result of measuring the shape of the measurement object S by destructive inspection or the like. Good. In this case, the correction coefficient may be expressed as a function of a correction coefficient γ calculated from the equation (1) and an experimental coefficient based on the result of the destructive inspection.

  In the third embodiment described above, the control device 5 has acquired a three-dimensional image for analysis for acquiring the shape information of the object to be measured S and the composition information of the substance constituting the object to be measured S. (Refer to step S32A). However, the configuration is not limited to such a configuration, and the control device 5 determines the shape information of the object to be measured S and the object to be measured based on the image obtained by reconstructing the projection data acquired in step S1 of FIG. You may acquire the composition information of the substance which comprises S. In this case, the control device 5 performs a correction process by calculating a correction coefficient γ based on the acquired shape information and composition information of the substance, and multiplying the projection data acquired in step S1 by the calculated correction coefficient γ. Then, the control device 5 reconstructs the projection data after the correction process and acquires a high-contrast image. In such a configuration, the data amount of the image reconstructed to acquire the shape information and the composition information of the substance may be small.

  Further, the X-ray apparatus 1 shown in FIG. 1 has a configuration in which the X-ray source 2 and the detector 4 are fixed and the stage 9 of the stage apparatus 3 rotates. However, the stage 9 of the stage device 3 may not rotate, and the X-ray source 2 and the detector 4 may rotate around the stage 9.

  Moreover, the control apparatus 5 is comprised with the computer which has an automatic calculation function, for example. In the X-ray apparatus 1, the X-ray source 2, the stage apparatus 3, the detector 4, and the control apparatus 5 may be configured separately. In this case, the X-ray source 2, the stage device 3, the detector 4, and the control device 5 are connected wirelessly or by wire. The X-ray apparatus 1 may be connected to another computer wirelessly or by wire.

  Further, the control device 5 has a calculation device such as a CPU, and has a program for causing the calculation device to execute the processes shown in FIGS. 5, 6, 10, and 12. This program is, for example, an image forming program for forming an image by detecting a signal from a device under test with a detector. The computer receives a signal from the device under test in the detector area. Performing correction processing for increasing the value of the first signal obtained in the first region and decreasing the value of the second signal obtained in the second region that does not receive a signal from the device under test; and data after the correction processing And reconstructing an image based on. This program is stored in the storage unit 53, for example. Further, this program can be stored in a storage medium such as a memory.

  In the above-described embodiment, the X-ray apparatus 1 has been described as an example. For example, it can be applied to single photon emission tomography (SPECT) and positron tomography (PET).

  Note that the requirements of the above-described embodiments can be combined as appropriate. Some components may not be used. In addition, as long as it is permitted by law, the disclosures of all published publications and US patents related to the X-ray detection apparatus and the like cited in the above embodiments and modifications are incorporated herein by reference.

  DESCRIPTION OF SYMBOLS 1 ... X-ray apparatus, 2 ... X-ray source, 3 ... Stage apparatus, 4 ... Detector, 5 ... Control apparatus, 51 ... Acquisition part, 52 ... Processing part, 53 ... Memory | storage part, 710 ... Design apparatus, 720 ... Molding Device, 730 ... Control device (inspection device), SYS ... Structure manufacturing system, S ... Measurement object, XL ... X-ray

Claims (19)

An X-ray source emitting X-rays;
A detector for detecting the X-rays emitted from the X-ray source;
Of the area of the detector, the first projection data obtained in the first area where the object to be measured is between the X-ray source and the second area without the object to be measured between the X-ray source The second projection data obtained in step (b) is subjected to filter correction processing by a filter correction back projection method, the value of the first projection data after the filter correction processing is increased, and the second projection data after the filter correction processing A processing unit that performs correction processing to reduce the value of the image and reconstructs the image,
The processing unit assumes that the amount of photons detected in the first region when the X-ray photons are scattered by the object to be measured and that the X-ray photons are not scattered by the object to be measured. An X-ray apparatus that performs the correction processing based on a correction coefficient according to a ratio with a photon amount detected in the first region. An X-ray source emitting X-rays;
A detector for detecting the X-rays emitted from the X-ray source;
Of the area of the detector, the first projection data obtained in the first area where the object to be measured is between the X-ray source and the second area without the object to be measured between the X-ray source The second projection data obtained in step (b) is subjected to filter correction processing by a filter correction back projection method, the value of the first projection data after the filter correction processing is increased, and the second projection data after the filter correction processing A processing unit that performs correction processing to reduce the value of the image and reconstructs the image,
The processing unit is an X-ray apparatus that performs the correction processing using information on an energy spectrum of the X-ray and information on a composition of the object to be measured. An X-ray source emitting X-rays;
A detector for detecting the X-rays emitted from the X-ray source;
Of the area of the detector, the first projection data obtained in the first area where the object to be measured is between the X-ray source and the second area without the object to be measured between the X-ray source The second projection data obtained in step (b) is subjected to filter correction processing by a filter correction back projection method, the value of the first projection data after the filter correction processing is increased, and the second projection data after the filter correction processing A processing unit that performs correction processing to reduce the value of the image and reconstructs the image,
The processing unit is an X-ray apparatus that performs the correction process by estimating a state in which the X-ray is not scattered by the object to be measured. The X-ray apparatus according to any one of claims 1 to 3,
When the portion where X-rays are attenuated is positive with respect to the first projection data and the second projection data , the processing unit is expressed as negative otherwise, and as the distance from the portion where X-rays are attenuated, An X-ray apparatus that performs filter correction processing using a function that approaches zero . The X-ray apparatus according to any one of claims 1 to 4 ,
The X-ray apparatus, wherein the processing unit performs the correction process by multiplying the first projection data and the second projection data by the correction coefficient. The X-ray apparatus according to claim 5,
The X-ray apparatus, wherein the processing unit calculates the correction coefficient using spectral information related to an energy spectrum of the X-rays emitted from the X-ray source and composition information of a substance constituting the measurement object. The X-ray apparatus according to claim 6,
The X-ray apparatus, wherein the processing unit calculates the correction coefficient using an absorption coefficient of the substance at the X-ray energy and a scattering coefficient of the substance at the X-ray energy. The X-ray apparatus according to claim 6,
The X-ray apparatus, wherein the processing unit calculates the correction coefficient using a distance that can be moved until the photons of the X-ray light are absorbed or scattered in the substance. The X-ray apparatus according to any one of claims 6 to 8,
The processing unit is an X-ray apparatus that acquires composition information of a substance constituting the measurement object based on product information of the measurement object. The X-ray apparatus according to any one of claims 6 to 8,
The processing unit analyzes a three-dimensional image for analysis reconstructed based on the first projection data and the second projection data before performing the correction process, and thereby the composition of the substance constituting the object to be measured An X-ray device that acquires information. The X-ray apparatus according to claim 10,
The processing unit performs the correction processing to reconstruct the image as the first projection data and the second projection data for reconstructing the three-dimensional image for analysis, An X-ray apparatus that obtains from the detector with a reduced data amount with respect to the second projection data. The X-ray apparatus according to claim 10 or 11,
The processing unit is configured to reduce the intensity of the X-ray for reconstructing the three-dimensional image for analysis to be lower than the intensity of the X-ray when the image is reconstructed by performing the correction process. . The X-ray apparatus according to any one of claims 1 to 12,
The X-ray apparatus, wherein the correction coefficient is set according to a distance that the X-ray passes through the object to be measured. The X-ray apparatus according to claim 13,
The X-ray apparatus, wherein the processing unit calculates a distance that the X-ray passes through the measurement object based on a shape of the measurement object and a projection angle of the X-ray with respect to the measurement object. The X-ray apparatus according to claim 13,
The X-ray apparatus, wherein the processing unit calculates a distance that the X-ray passes through the device under test based on shape information of the device under test. An image forming method for forming an image by detecting a signal from an object to be measured by a detector,
Detecting the X-rays emitted from an X-ray source emitting X-rays with the detector;
Using the information on the energy spectrum of the X-ray and the information on the composition of the object to be measured, it is obtained in the first region where the object to be measured is located between the detector and the X-ray source. Filter correction processing by filter correction back projection is performed on the first projection data and second projection data obtained in the second region where the object to be measured is not between the X-ray source and the filter correction processing. Performing a correction process to increase the value of the first projection data and to decrease the value of the second projection data after the filter correction process ;
Reconstructing an image based on the data after the correction process. A design process for creating design information on the shape of the structure;
A molding step for creating the structure based on the design information;
A step of measuring the shape of the manufactured structure using the X-ray apparatus according to any one of claims 1 to 15,
A structure manufacturing method comprising: an inspection process for comparing the shape information obtained in the measurement process and the design information.   The method for manufacturing a structure according to claim 17, further comprising a repair process that is executed based on a comparison result of the inspection process and performs reworking of the structure. A design device for creating design information on the shape of the structure;
A molding apparatus for producing the structure based on the design information;
The X-ray apparatus according to any one of claims 1 to 15, which measures the shape of the manufactured structure.
A structure manufacturing system including an inspection apparatus that compares shape information regarding the shape of the structure obtained by the X-ray apparatus and the design information.

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