Method for aligning three-dimensional image data and X-ray imaging device

Abstract

This method for aligning three-dimensional image data comprises a step for generating first CT data (23) on the basis of first X-ray image data (22), a step for generating second CT data (25) on the basis of second X-ray image data (24), and a step for aligning the first CT data (23) and the second CT data (25) on the basis of an alignment member (30) in the first CT data (23) and the second CT data (25).

Description

Technical Field

[0001] The invention relates to a three-dimensional image data alignment method and an X-ray photography device. Background Art

[0002] Conventionally, there is known a method for aligning three-dimensional image data, which aligns first computed tomography (CT) data generated based on a first X-ray image and second CT data generated based on a second X-ray image and including an overlapping range that overlaps with the imaging range of the first CT data. Such a device is disclosed in, for example, Japanese Patent Laid-Open No. 2014-61278.

[0003] In the Japanese Patent Publication No. 2014-61278, as a photography method using an X-ray CT device (X-ray photography device), the following method is disclosed, that is, after a part of the subject is irradiated with X-rays and an image (first X-ray image) is photographed, the subject is moved a predetermined distance in the body axis direction while the X-ray irradiation is stopped, and the other part of the subject is irradiated with X-rays and an image (second X-ray image) is photographed. The Japanese Patent Publication No. 2014-61278 discloses the following: the images of each part of the subject are photographed in a manner having an overlapping area (overlapping range) used in synthesis. The Japanese Patent Publication No. 2014-61278 discloses the following: such movement of the subject and local photography of the subject are repeated, and the images of each part of the subject are synthesized, thereby obtaining a wide range image of the subject.

[0004] Although it is not clearly stated in the Japanese Patent Laid-Open No. 2014-61278, the X-ray CT apparatus (X-ray imaging apparatus) shown in the Japanese Patent Laid-Open No. 2014-61278 is considered to be a medical X-ray imaging apparatus. In contrast, in an X-ray imaging apparatus not for medical use but for measurement, the following operation is also performed, that is, the movement of the imaging unit and the imaging of a part of the object are repeated, and the CT data of each part of the object are synthesized to obtain the CT data of the entire object. At this time, the images of each part of the object are photographed in a manner having an overlapping area used in the synthesis.

[0005] However, when synthesizing the CT data of each part of the object, it is difficult to find the relative positional relationship between the CT data of each part of the object due to the inclination of the object mounting part on which the object is mounted, or the movement (drift) of the X-ray focus caused by the deformation caused by the thermal expansion of the X-ray tube. In addition, in the method called the best fit, which uses one of the shape data as a reference to move another shape data parallel or rotationally to a position where the relative distance to one of the shape data is the smallest, the larger the shape, the more it helps positioning. In the above case, the larger the shape, the longer the path length of the X-rays that pass through, so sometimes it is easy to produce errors in the surface shape due to artifacts. Therefore, in the best fit method, shape data that may contain errors is used when combining CT data, so it is sometimes difficult to align the shape data. As described above, when synthesizing the CT data of each part of the object to generate the CT data of the entire object, there is a problem that it is difficult to align the CT data of each part of the object. Therefore, it is expected to align multiple CT data with good accuracy. Summary of the invention

[0006] The present invention is made to solve the above-mentioned problems, and one object of the present invention is to provide a three-dimensional image data alignment method and an X-ray imaging device capable of aligning a plurality of CT data with high accuracy.

[0007] In order to achieve the above-mentioned purpose, a three-dimensional image data alignment method according to a first aspect of the present invention comprises the following steps: generating three-dimensional first CT data based on first X-ray image data, wherein the first X-ray image data is obtained by performing X-ray photography of a first part of a subject and at least three positioning members having an isotropic shape; generating three-dimensional second CT data based on second X-ray image data, wherein the second X-ray image data is obtained by performing X-ray photography of a second part including an overlapping range overlapping with the photography range of the first CT data and including a part of the first part of the subject, and at least three positioning members arranged in the overlapping range; and aligning the first CT data with the second CT data based on the positioning members having an isotropic shape in the first CT data and the second CT data.

[0008] An X-ray imaging apparatus according to a second aspect of the present invention includes: an imaging unit including an X-ray source for irradiating X-rays and a detector for detecting the X-rays irradiated from the X-ray source, and imaging a subject; and an image processing unit generating CT data based on a plurality of X-ray image data obtained by imaging from a plurality of angles at which the subject and the imaging unit have different relative angles, the image processing unit generating three-dimensional first CT data based on first X-ray image data, the first X-ray image data being acquired by performing X-ray imaging of a first portion of the subject and at least three positioning members having an isotropic shape by the imaging unit; generating three-dimensional second CT data based on second X-ray image data, the second X-ray image data being acquired by performing X-ray imaging of a second portion including an overlapping range overlapping with the imaging range of the first CT data and including a portion of the first portion of the subject, and at least three positioning members arranged in the overlapping range by the imaging unit; and performing alignment of the first CT data and the second CT data based on the positioning members having an isotropic shape in the first CT data and the second CT data.

[0009] In the three-dimensional image data alignment method of the first aspect and the X-ray imaging device of the second aspect, as described above, three-dimensional first CT data is generated based on first X-ray image data, the first X-ray image data is obtained by performing X-ray imaging of a first portion of a subject and at least three positioning members having an isotropic shape by an imaging unit; three-dimensional second CT data is generated based on second X-ray image data, the second X-ray image data is obtained by performing X-ray imaging of a second portion including a portion of the first portion of the subject and at least three positioning members arranged in an overlapping range by an imaging unit; and the first CT data and the second CT data are aligned based on the positioning members having an isotropic shape in the first CT data and the second CT data. Thus, even if the positions of the various portions of the subject are offset between the CT data due to the tilt of the subject mounting portion or the movement (drift) of the X-ray focus, the first CT data and the second CT data can be aligned with good accuracy based on the at least three positioning members arranged in the overlapping range of the first CT data and the second CT data. In addition, in the first CT data and the second CT data generated based on the X-ray image data obtained by rotating the positioning member while photographing, the positioning member has an isotropic shape, so the center position of the positioning member can be obtained with good accuracy. Therefore, compared with the best fit method for aligning shape data that may contain errors, the first CT data and the second CT data can be aligned with good accuracy based on the positioning member having an isotropic shape. For these reasons, the first CT data and the second CT data can be aligned with good accuracy. Therefore, a plurality of CT data can be aligned with good accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is a block diagram showing an example of an X-ray imaging apparatus according to one embodiment.

[0011] Figure 2 It is a schematic diagram for explaining the acquisition of the first X-ray image data.

[0012] Figure 3 It is a schematic diagram for explaining the acquisition of the second X-ray image data.

[0013] Figure 4 It is a schematic perspective view showing an example of a positioning jig and a positioning member.

[0014] Figure 5 It is a schematic plan view showing an example of a positioning jig and a positioning member.

[0015] Figure 6 This is a diagram for explaining the process of acquiring the first position information.

[0016] Figure 7 This is a diagram for explaining the process of acquiring the second position information.

[0017] Figure 8 This is a flowchart for explaining the alignment processing of the first CT data and the second CT data.

[0018] Fig. 9 It is a schematic perspective view showing an example of a positioning jig and a positioning member according to a first modification.

[0019] Fig.10 (a) and Fig.10 (b) is a schematic diagram showing an example of a positioning jig and a positioning member according to a second modification.

[0020] Fig.11 (a) and Fig.11 (b) is a schematic diagram showing another example of the positioning jig and the positioning member according to the second modification.

[0021] Fig.12 (a) and Fig.12 (b) is a schematic diagram showing an example of a positioning jig and a positioning member according to a third modified example. DETAILED DESCRIPTION

[0022] Hereinafter, embodiments of the present invention will be described based on the drawings.

[0023] (Overall structure of X-ray imaging device)

[0024] Reference Figure 1 to Figure 7 The overall structure of the X-ray imaging apparatus 100 according to this embodiment will be described.

[0025] like Figure 1 As shown, the X-ray imaging device 100 includes an imaging unit 1, a control unit 10, a storage unit 20, and a moving rotation mechanism 60. The imaging unit 1 includes an X-ray source 2 and a detector 3. The control unit 10 includes an image processing unit 11 and an imaging control unit 12.

[0026] The X-ray source 2 is configured to irradiate X-rays to the subject 40. Specifically, the X-ray source 2 is configured to generate X-rays by causing electrons generated by applying a high voltage to an electrode to collide with a target. The X-ray source 2 is, for example, an X-ray generating device including an X-ray tube and a power supply.

[0027] The detector 3 is configured to detect the X-rays irradiated from the X-ray source 2. In addition, the detector 3 is configured to convert the detected X-rays into an electrical signal (image signal). The detector 3 includes a light receiving unit for receiving the X-rays, and a conversion unit for converting the received X-rays into an image signal. The detector 3 is, for example, a flat panel detector (Flat Panel Detector, FPD). The detector 3 includes a plurality of conversion elements (not shown) and pixel electrodes (not shown) arranged on the plurality of conversion elements. The image signal of the detector 3 is sent to the image processing unit 11.

[0028] The control unit 10 includes a processor such as a central processing unit (CPU), a field programmable gate array (FPGA), or an application specific integrated circuit (ASIC). The control unit 10 as hardware includes an image processing unit 11 and a photography control unit 12 as functional blocks of software (program). The control unit 10 functions as the image processing unit 11 and the photography control unit 12 by executing the program 21 stored in the storage unit 20. The image processing unit 11 and the photography control unit 12 may be individually configured by hardware by providing a dedicated processor (processing circuit).

[0029] The image processing unit 11 is configured to control the detector 3. Figure 2As shown, the image processing unit 11 is configured to acquire first X-ray image data 22 based on X-rays detected by the detector 3 by performing X-ray photography of the first portion 41 of the object 40 and the three positioning members 30 having an isotropic shape. In addition, the image processing unit 11 is configured to acquire a plurality of first X-ray image data 22 acquired by performing photography while rotating the object 40 around the axis 43 by the moving rotation mechanism 60. In addition, the image processing unit 11 is configured to generate first CT data 23 based on the acquired plurality of first X-ray image data 22. That is, the image processing unit 11 generates the first CT data 23 based on a plurality of first X-ray image data 22 acquired by performing photography from a plurality of angles at which the relative angles between the object 40 and the photography unit 1 are different.

[0030] In addition, if Figure 3 As shown, the image processing unit 11 is configured to acquire second X-ray image data 24 based on X-rays detected by the detector 3 by performing X-ray imaging on the second portion 42 including a part of the first portion 41 of the subject 40 and the three positioning members 30 arranged in the overlapping range 26, which includes an overlapping range 26 overlapping with the imaging range of the first CT data 23. The overlapping range 26, which is the imaging range overlapping with the first CT data 23, includes a first range 26a overlapping in the direction of the axis 43 of the rotation axis of the subject 40 orthogonal to the straight line connecting the X-ray source 2 and the detector 3. In addition, the image processing unit 11 is configured to acquire a plurality of second X-ray image data 24 obtained by imaging while rotating the subject 40 around the axis 43 by the moving rotation mechanism 60. In addition, the image processing unit 11 is configured to generate second CT data 25 based on the plurality of acquired second X-ray image data 24. That is, the image processing unit 11 generates the second CT data 25 based on the plurality of second X-ray image data 24 acquired by imaging at a plurality of different relative angles between the subject 40 and the imaging unit 1 .

[0031] That is, in this embodiment, Figure 2 As shown, by performing X-ray photography on the first portion 41 of the upper portion of the object 40 and the three positioning members 30, the first X-ray image data 22 with the first portion 41 of the upper portion of the object 40 as the photography range is obtained. Figure 3 As shown, the second X-ray image data 24 is acquired by performing X-ray imaging on the second portion 42 which is the lower portion of the object 40 and includes a portion of the upper portion of the object 40 , and the three positioning members 30 arranged in the overlapping range 26 .

[0032] In addition, the image processing unit 11 is configured to perform alignment between the first CT data 23 and the second CT data 25 based on the positioning member 30 having an isotropic shape in the first CT data 23 and the second CT data 25. That is, the image processing unit 11 performs alignment within the overlapping range 26 of the first CT data 23 and the second CT data 25 based on the positioning member 30, and synthesizes the first CT data 23 and the second CT data 25, thereby obtaining CT data of the entire object 40.

[0033] In addition, the image processing unit 11 is configured to obtain a first distance 34 (see FIG. 1 ) between at least two of the three positioning members 30 in the first CT data 23 when the magnification of the object 40 in the first CT data 23 is different from the magnification of the object 40 in the second CT data 25. Figure 6 ), and a second distance 35 between at least two positioning members 30 corresponding to the first distance 34 in the second CT data 25 (refer to Figure 7 ) so that at least one of the first CT data 23 and the second CT data 25 is enlarged or reduced in a manner that makes the first distance 34 and the second distance 35 consistent, thereby aligning the first CT data 23 and the second CT data 25.

[0034] like Figure 1 As shown, the imaging control unit 12 controls the operation of the X-ray source 2. In addition, the imaging control unit 12 controls the operation of the moving and rotating mechanism 60. The imaging control unit 12 includes a control device for the X-ray source 2, a control device for the moving and rotating mechanism 60, and the like. When acquiring a plurality of first X-ray image data 22 and acquiring a plurality of second X-ray image data 24, the imaging control unit 12 controls the irradiation of X-rays from the X-ray source 2 and controls the irradiation to stop, and controls the moving and rotating mechanism 60 to position the object 40 in sequence at a plurality of imaging angles. In addition, in order to acquire a plurality of second X-ray image data 24 after acquiring a plurality of first X-ray image data 22, the imaging control unit 12 controls the moving and rotating mechanism 60 to move the object 40 in the vertical direction.

[0035] The storage unit 20 includes a nonvolatile storage device. The nonvolatile storage device is, for example, a hard disk drive, a solid state drive, etc. Various programs 21 executed by the processor are stored in the storage unit 20. In addition, a plurality of first X-ray image data 22 and first CT data 23 generated based on the plurality of first X-ray image data 22 are stored in the storage unit 20. In addition, a plurality of second X-ray image data 24 and second CT data 25 generated based on the plurality of second X-ray image data 24 are stored in the storage unit 20.

[0036] In the present embodiment, X-ray photography is performed in a state where a positioning jig 50 provided with three positioning members 30 is arranged on a subject placing portion 61 on which a subject 40 is placed, thereby acquiring first X-ray image data 22 and second X-ray image data 24 of the subject 40 and the positioning members 30. Then, the image processing unit 11 generates first CT data 23 based on the plurality of first X-ray image data 22, and generates second CT data 25 based on the plurality of second X-ray image data 24. Then, the image processing unit 11 performs alignment of the first CT data 23 and the second CT data 25 based on the center point 31 of the three positioning members 30. In addition, the center point 31 of the positioning member 30 is an example of the "center position of the positioning member" in the claims.

[0037] The moving and rotating mechanism 60 is configured to rotate the subject 40 around the axis 43. The moving and rotating mechanism 60 includes a subject placement portion 61 on which the subject 40 is placed, a rotating portion (not shown) that rotates the subject placement portion 61, a rotation driving portion (not shown) that applies a driving force to the rotating portion, a moving portion (not shown) that moves the subject placement portion 61 in a vertical direction, and a moving driving portion (not shown) that applies a driving force to the moving portion. The rotation driving portion and the moving driving portion include, for example, a motor.

[0038] (Positioning fixture and positioning components)

[0039] like Figure 4 As shown in FIG. 1 , the positioning jig 50 is configured to fix the positioning member 30. The positioning jig 50 is arranged on the subject placement portion 61 (see FIG. 1 ). Figure 1 The positioning jig 50 is arranged on the subject placement portion 61 so as to surround the periphery of the subject 40. The positioning jig 50 is formed of a cylindrical member. When the subject placement portion 61 on which the subject 40 is placed moves to one side in the vertical direction by the moving portion, the positioning jig 50 moves to one side in the vertical direction together with the subject 40.

[0040] The positioning fixture 50 is formed of a pipe made of, for example, carbon fiber reinforced polymer (CFRP). The material of the positioning fixture 50 is not particularly limited as long as it is a material with high X-ray transmittance. By using a material with high X-ray transmittance as the material of the positioning fixture 50, the influence of the shadow of the positioning fixture 50 in the X-ray image can be suppressed.

[0041] Three positioning members 30 are fixedly provided on the outer peripheral surface of the positioning fixture 50. Thus, at least before the X-ray photography is completed, the relative positions of the positioning members 30 will not change. As a method of fixing the positioning members 30 to the positioning fixture 50, there are fixing with an adhesive, screwing, etc., but as long as the positioning members 30 can be fixed to the positioning fixture 50, the method is not limited.

[0042] like Figure 2 and Figure 3 As shown, the positioning member 30 is disposed at a position in the positioning fixture 50 corresponding to the overlapping range 26 where the imaging range of the first CT data 23 (the imaging range 22a of the first X-ray image data 22) and the imaging range of the second CT data 25 (the imaging range 24a of the second X-ray image data 24) overlap. Figure 5 As shown, the center points 31 of the three positioning members 30 are respectively configured to determine a plane 36 by the three center points 31, rather than being on the same straight line. In addition, a plane 36 determined by the center points 31 of the three positioning members 30 can be parallel to the horizontal plane or can intersect with the horizontal plane.

[0043] In addition, the three positioning members 30 are arranged at intervals of approximately 120 degrees on the outer peripheral surface of the positioning jig 50 in a plan view. In addition, the three positioning members 30 may be arranged at arbitrary angular intervals instead of approximately 120 degrees on the outer peripheral surface of the positioning jig 50.

[0044] The positioning member 30 is arranged on the positioning fixture 50 in such a manner that the entire positioning member 30 is included in the overlapping range 26. As described in detail later, the image processing unit 11 obtains the position information of the center point 31 of the positioning member 30 in the first coordinate system (first position information 32), and obtains the position information of the center point 31 of the positioning member 30 in the second coordinate system (second position information 33). In addition, as described later, the positioning member 30 has a spherical shape. Since high-precision measurements can be performed even if the spherical shape is small, the size of the positioning member 30 can be reduced to a level that does not affect the first CT data 23 and the second CT data 25. For example, in Figure 2 and Figure 3 In the horizontal direction of the overlapping range 26 of the imaging range of the first CT data 23 (the imaging range 22a of the first X-ray image data 22) and the imaging range of the second CT data 25 (the imaging range 24a of the second X-ray image data 24), there is no problem in setting the proportion of the positioning member 30 to be less than one twentieth. In addition, for the sake of convenience of explanation, the size of the positioning member 30 shown in the figure is different from the actual size.

[0045] like Figure 4 and Figure 5As shown, the positioning member 30 has an isotropic shape. Specifically, the positioning member 30 has a shape that is point-symmetrical with respect to the center of the positioning member 30 as the isotropic shape. More specifically, the positioning member 30 has a spherical shape as the point-symmetrical shape. In addition, the so-called isotropic shape means that the shape of the positioning member 30 has no directivity or low directivity.

[0046] The positioning member 30 is formed of a material having the same or similar X-ray transmittance as the object 40. The positioning member 30 is formed of, for example, ceramic. The material of the positioning member 30 is not limited to ceramic, and may be, for example, a metal such as aluminum or iron, or a resin. In addition, the specific gravity of the material of the positioning member 30 is preferably smaller than the specific gravity of the material of the object 40. The reason for this is that, when the specific gravity of the material of the positioning member 30 is greater than the specific gravity of the material of the object 40, there is a possibility of generating artifacts (noise) due to the high absorption coefficient of the positioning member 30.

[0047] (Acquisition of First X-ray Image Data and Generation of First CT Data)

[0048] Next, refer to Figure 2 The acquisition of the first X-ray image data 22 and the generation of the first CT data 23 will be described.

[0049] The subject 40 is placed on the subject placement portion 61. The cylindrical positioning jig 50 is arranged in the subject placement portion 61 so as to surround the subject 40. The positioning jig 50 has a cylindrical shape. In addition, the positioning jig 50 is not limited to a cylindrical shape, and may also be a square cylindrical shape.

[0050] Three positioning members 30 are fixedly provided on the outer peripheral surface of the positioning jig 50. The three positioning members 30 are arranged in the positioning jig 50 in a range corresponding to the overlapping range 26 of the imaging range of the first CT data 23 (the imaging range 22a of the first X-ray image data 22) and the imaging range of the second CT data 25 (the imaging range 24a of the second X-ray image data 24). The first part 41 of the object 40 is set as the imaging range 22a of the first X-ray image data 22. The object placing part 61 is moved in the vertical direction by the moving part so that the first part 41 of the object 40 becomes the imaging range.

[0051] Then, by changing the imaging angle of the object 40 by using the rotating mechanism, the imaging unit 1 takes an X-ray image of the object 40 at each of the plurality of imaging angles set in advance. The first portion 41 of the object 40 and the three positioning members 30 are X-rayed together. The image processing unit 11 acquires (generates) the first X-ray image data 22 based on the detection signal (image signal) of the detector 3 for each of the plurality of imaging angles set in advance. The first X-ray image data 22 for each imaging angle is acquired over the predetermined angle range set in advance.

[0052] Image processing unit 11 (see Figure 1 ) is configured to generate first CT data 23 based on the acquired plurality of first X-ray image data 22. The image processing unit 11 generates the first CT data 23 by performing reconstruction processing on a group of a plurality of first X-ray image data 22 required for one CT imaging for each imaging angle. The first CT data 23 is an image reflecting the three-dimensional structure of the first portion 41 of the object 40. The first CT data 23 may be in the form of a tomographic image, a three-dimensional stereo image, or the like of the first portion 41 of the object 40.

[0053] (Acquisition of Second X-ray Image Data and Generation of Second CT Data)

[0054] Next, refer to Figure 3 The acquisition of the second X-ray image data 24 and the generation of the second CT data 25 will be described. In the present embodiment, after the plurality of first X-ray image data 22 are acquired, the plurality of second X-ray image data 24 are acquired.

[0055] The second portion 42 of the subject 40 is set as the imaging range 24a of the second X-ray image data 24. The second portion 42 of the subject 40 includes a portion of the first portion 41 of the subject 40. That is, a portion of the first portion 41 of the subject 40 in the second portion 42 of the subject 40 is the overlapping range 26. In order to image a plurality of second X-ray image data 24 after imaging a plurality of first X-ray image data 22, the subject placement portion 61 is moved in the upward direction along the axis 43 of the rotation axis of the subject 40 by the moving portion so that the second portion 42 of the subject 40 becomes the imaging range.

[0056] Then, by changing the imaging angle of the object 40 by using the rotating mechanism, the imaging unit 1 takes an X-ray image of the object 40 at each of the plurality of imaging angles set in advance. X-ray imaging is performed on the second portion 42 of the object 40 and the three positioning members 30 at the same time. The acquisition of the second X-ray image data 24 and the generation of the second CT data 25 by the image processing unit 11 are performed by the same method as the acquisition of the first X-ray image data 22 and the generation of the first CT data 23, and therefore, the description thereof is omitted.

[0057] (Acquisition of the center position of the positioning component)

[0058] The image processing unit 11 acquires the shape of the positioning member 30 in the first CT data 23 and the second CT data 25. In the present embodiment, the image processing unit 11 specifies the shape of the positioning member 30. There is no limitation on the method by which the image processing unit 11 specifies the shape of the positioning member 30. In addition, the first CT data 23 is set as data representing the shape of the three-dimensional object 40 in the first coordinate system defined by the P axis, the Q axis, and the R axis. In addition, the second CT data 25 is set as data representing the shape of the three-dimensional object 40 in the second coordinate system defined by the S axis, the T axis, and the U axis.

[0059] like Figure 6 As shown, the image processing unit 11 obtains the first position information 32 (refer to Figure 1 ). The image processing unit 11 obtains the position information of the positioning member 30 in the first CT data 23, that is, the first position information 32, based on the isotropic shape of the positioning member 30 in the first CT data 23. The first position information 32 includes the position information of the center point 31 of the positioning member 30 in the first coordinate system. The acquisition of the center point 31 of the positioning member 30 in the first CT data 23 by the image processing unit 11 is performed by a well-known method, and the acquisition method is not particularly limited.

[0060] The positioning member 30 is spherical in shape, which is an isotropic shape. Therefore, the image processing unit 11 can obtain the position information (first position information 32) of the center point 31 of the positioning member 30 in the first coordinate system with good accuracy. The image processing unit 11 obtains the position coordinates (P1, Q1, R1) of the center point 31a in the first coordinate system as the first position information 32 of the positioning member 30a. In addition, the image processing unit 11 obtains the position coordinates (P2, Q2, R2) of the center point 31b in the first coordinate system as the first position information 32 of the positioning member 30b. In addition, the image processing unit 11 obtains the position coordinates (P3, Q3, R3) of the center point 31c in the first coordinate system as the first position information 32 of the positioning member 30c. The obtained first position information 32 is stored in the storage unit 20 (refer to Figure 1 ).

[0061] like Figure 7 As shown, the image processing unit 11 obtains the second position information 33 (refer to Figure 1 ). The second position information 33 includes the position information of the center point 31 of the positioning member 30 in the second coordinate system. The acquisition of the center point 31 of the positioning member 30 in the second CT data 25 by the image processing unit 11 is performed by a well-known method, and the acquisition method is not particularly limited. The image processing unit 11 acquires the position coordinates (S1, T1, U1) of the center point 31a in the second coordinate system as the second position information 33 of the positioning member 30a. In addition, the image processing unit 11 acquires the position coordinates (S2, T2, U2) of the center point 31b in the second coordinate system as the second position information 33 of the positioning member 30b. In addition, the image processing unit 11 acquires the position coordinates (S3, T3, U3) of the center point 31c in the second coordinate system as the second position information 33 of the positioning member 30c. The acquired second position information 33 is stored in the storage unit 20 (refer to Figure 1 )middle.

[0062] (The object magnification of the first CT data is consistent with the object magnification of the second CT data)

[0063] The image processing unit 11 obtains at least one of the distance between the center point 31a of the positioning member 30a and the center point 31b of the positioning member 30b, the distance between the center point 31a of the positioning member 30a and the center point 31c of the positioning member 30c, and the distance between the center point 31b of the positioning member 30b and the center point 31c of the positioning member 30c in the first coordinate system based on the first position information 32 in the first CT data 23. In the present embodiment, the image processing unit 11 obtains the straight-line distance between the center point 31a of the positioning member 30a and the center point 31b of the positioning member 30b in the first coordinate system as the first distance 34 (see Figure 6 ).

[0064] In addition, the image processing unit 11 obtains at least one of the distance between the center point 31a of the positioning member 30a and the center point 31b of the positioning member 30b, the distance between the center point 31a of the positioning member 30a and the center point 31c of the positioning member 30c, and the distance between the center point 31b of the positioning member 30b and the center point 31c of the positioning member 30c in the second coordinate system based on the second position information 33 in the second CT data 25. In the present embodiment, the image processing unit 11 obtains the straight-line distance between the center point 31a of the positioning member 30a and the center point 31b of the positioning member 30b in the second coordinate system as the second distance 35 (see Figure 7 ).

[0065] Then, when the first distance 34 in the first CT data 23 and the second distance 35 in the second CT data 25 do not match, the image processing unit 11 enlarges or reduces at least one of the first CT data 23 and the second CT data 25 so that the first distance 34 and the second distance 35 match. Thus, the object magnification of the first CT data 23 and the object magnification of the second CT data 25 are made to match. In the present embodiment, the image processing unit 11 is configured to enlarge or reduce the second CT data 25 so that the second distance 35 in the second CT data 25 matches the first distance 34 in the first CT data 23. In this case, the image processing unit 11 converts the second position information 33 in the second CT data 25 according to the enlargement or reduction of the second CT data 25. In addition, the image processing unit 11 may be configured to enlarge or reduce the first CT data 23 so that the first distance 34 in the first CT data 23 and the second distance 35 in the second CT data 25 match.

[0066] (Alignment of the first CT data and the second CT data)

[0067] The image processing unit 11 performs positional alignment between the first CT data 23 and the second CT data 25 based on the first position information 32 and the second position information 33 .

[0068] Specifically, the image processing unit 11 performs alignment between the first CT data 23 and the second CT data 25 by matching the positions of the first position information 32 and the second position information 33. That is, the image processing unit 11 matches the position coordinates (P1, Q1, R1) of the center point 31a in the first CT data 23 with the position coordinates (S1, T1, U1) of the center point 31a in the second CT data 25. In addition, the image processing unit 11 matches the position coordinates (P2, Q2, R2) of the center point 31b in the first CT data 23 with the position coordinates (S2, T2, U2) of the center point 31b in the second CT data 25. In addition, the image processing unit 11 matches the position coordinates (P3, Q3, R3) of the center point 31c in the first CT data 23 with the position coordinates (S3, T3, U3) of the center point 31c in the second CT data 25. In this way, the first CT data 23 and the second CT data 25 are aligned.

[0069] In addition, regarding the image processing unit 11, when the second position information 33 in the second CT data 25 is converted according to the enlargement or reduction of the second CT data 25, the image processing unit 11 makes the positions of the respective first position information 32 coincide with the positions of the respective second position information 33 after the conversion, thereby aligning the first CT data 23 and the second CT data 25.

[0070] (Alignment Processing of First CT Data and Second CT Data)

[0071] Reference Figure 8 The alignment processing of the first CT data 23 and the second CT data 25 according to the present embodiment will be described. In addition, the control of the imaging operation is performed by the imaging control unit 12. The acquisition of the first X-ray image data 22, the acquisition of the second X-ray image data 24, the generation of the first CT data 23, the generation of the second CT data 25, and the alignment of the first CT data 23 and the second CT data 25 are performed by the image processing unit 11. In addition, the order of the processing steps may be reversed or executed simultaneously as long as there is no contradiction.

[0072] In step S1, the image processing unit 11 acquires a plurality of first X-ray image data 22 by performing X-ray imaging of the first portion 41 of the object 40 and the three positioning members 30 at the same time and performing multiple imaging operations while rotating the object 40 around the axis 43. Then, the process proceeds to step S2.

[0073] In step S2, the photographing control unit 12 moves the subject placement unit 61 in the upward direction along the axis 43 of the rotation axis of the subject 40 via the moving unit so that the second portion 42 of the subject 40 becomes the photographing range. Then, the process proceeds to step S3.

[0074] In step S3, the image processing unit 11 performs X-ray imaging of the second portion 42 including the overlapping range 26 overlapping with the imaging range of the first CT data 23 (first X-ray image data 22) and including a part of the first portion 41 of the object 40, and the three positioning members 30 arranged in the overlapping range 26, and performs imaging multiple times while rotating the object 40 around the axis 43, thereby acquiring a plurality of second X-ray image data 24. Then, the process proceeds to step S4.

[0075] In step S4, the image processing unit 11 generates the first CT data 23 based on the plurality of first X-ray image data 22. Then, the process proceeds to step S5.

[0076] In step S5, the image processing unit 11 acquires the first position information 32 of the center point 31 of the positioning member 30 in the first coordinate system based on the first CT data 23, and acquires the first distance 34 in the first coordinate system. Then, the process proceeds to step S6.

[0077] In step S6, the image processing unit 11 generates the second CT data 25 based on the plurality of second X-ray image data 24. Then, the process proceeds to step S7.

[0078] In step S7, the image processing unit 11 acquires the second position information 33 of the center point 31 of the positioning member 30 in the second coordinate system based on the second CT data 25, and acquires the second distance 35 in the second coordinate system. Then, the process proceeds to step S8.

[0079] In step S8, with respect to the image processing unit 11, when the first distance 34 in the first CT data 23 and the second distance 35 in the second CT data 25 are different (Yes in step S8), the processing proceeds to step S9, and when the first distance 34 in the first CT data 23 and the second distance 35 in the second CT data 25 are consistent (No in step S8), the processing proceeds to step S10.

[0080] In step S9, the image processing unit 11 enlarges or reduces the second CT data 25 so that the second distance 35 in the second CT data 25 matches the first distance 34 in the first CT data 23. Thus, the object magnification of the first CT data 23 matches the object magnification of the second CT data 25. In addition, the image processing unit 11 converts the second position information 33 in the second CT data 25 according to the enlargement or reduction of the second CT data 25.

[0081] In step S10 , the image processing unit 11 performs positional alignment between the first CT data 23 and the second CT data 25 by aligning the positions of the first positional information 32 and the second positional information 33 . Then, the process ends.

[0082] (Effects of this embodiment)

[0083] In this embodiment, the following effects can be obtained.

[0084] In the present embodiment, as described above, the three-dimensional image data alignment method includes the following steps: generating three-dimensional first CT data 23 based on first X-ray image data 22, wherein the first X-ray image data 22 is obtained by performing X-ray photography of a first portion 41 of a subject 40 and three positioning members 30 having an isotropic shape by the imaging unit 1; generating three-dimensional second CT data 25 based on second X-ray image data 24, wherein the second X-ray image data 24 is obtained by performing X-ray photography of a second portion 42 including a portion of the first portion 41 of the subject 40 and three positioning members 30 arranged in an overlapping range 26 by the imaging unit 1; and aligning the first CT data 23 with the second CT data 25 based on the positioning members 30 having an isotropic shape in the first CT data 23 and the second CT data 25.

[0085] Thus, even when the positions of the various parts of the subject are offset between the CT data due to the tilt of the subject mounting unit 61 or the movement (drift) of the X-ray focus, the first CT data 23 and the second CT data 25 can be accurately aligned based on the three positioning members 30 arranged in the overlapping range 26 of the first CT data 23 and the second CT data 25. In addition, in the first CT data 23 and the second CT data 25 generated based on the X-ray image data obtained by rotating the positioning member 30 while photographing, the positioning member 30 has an isotropic shape, so the center position of the positioning member 30 can be accurately acquired. Therefore, compared with the best fit method of aligning shape data that may contain errors, the first CT data 23 and the second CT data 25 can be accurately aligned based on the positioning member 30 having an isotropic shape. For these reasons, the first CT data 23 and the second CT data 25 can be accurately aligned. Therefore, a plurality of CT data can be accurately aligned.

[0086] In addition, in the present embodiment, as described above, the X-ray imaging apparatus 100 includes the image processing unit 11, the image processing unit 11 generating CT data based on a plurality of X-ray image data obtained by imaging the object 40 at a plurality of angles at which the relative angles between the imaging unit 1 and the imaging unit 1 are different, and the image processing unit 11 generates three-dimensional first CT data 23 based on the first X-ray image data 22 obtained by performing X-ray imaging of the first portion 41 of the object 40 and the three positioning members 30 having an isotropic shape by the imaging unit 1; A three-dimensional second CT data 25 is generated based on the second X-ray image data 24, wherein the second X-ray image data 24 is obtained by performing X-ray photography by the photographing unit 1 on a second part 42 including an overlapping range 26 overlapping with the photographing range of the first CT data 23 and including a part of the first part 41 of the subject 40, and three positioning members 30 arranged in the overlapping range 26; the first CT data 23 and the second CT data 25 are aligned based on the positioning members 30 having an isotropic shape in the first CT data 23 and the second CT data 25.

[0087] Thus, similar to the above-mentioned method for aligning three-dimensional image data, even when the positions of the respective parts of the subject are offset between the CT data due to the tilt of the subject mounting unit 61 or the movement (drift) of the X-ray focus, the first CT data 23 and the second CT data 25 can be aligned with high accuracy based on the three positioning members 30 arranged in the overlapping range 26 of the first CT data 23 and the second CT data 25. In addition, in the first CT data 23 and the second CT data 25 generated based on the X-ray image data obtained by rotating the positioning members 30 while photographing, the positioning members 30 have an isotropic shape, so the center position of the positioning members 30 can be acquired with high accuracy. Therefore, compared with the best fit method for aligning shape data that may contain errors, the first CT data 23 and the second CT data 25 can be aligned with high accuracy based on the positioning members 30 having an isotropic shape. For these reasons, the first CT data 23 and the second CT data 25 can be aligned with high accuracy. Therefore, it is possible to provide an X-ray imaging apparatus 100 capable of accurately aligning a plurality of CT data.

[0088] In addition, in the above-mentioned embodiment, by constructing as follows, the following further effects can be obtained.

[0089] That is, in the present embodiment, as described above, the positioning member 30 has a shape that is point-symmetrical with respect to the center of the positioning member 30 as an isotropic shape, and in the step of aligning, the first CT data 23 and the second CT data 25 are aligned based on the point-symmetrical shape of the positioning member 30. Since the positioning member 30 has a point-symmetrical shape, the center position of the positioning member 30 in the first CT data 23 and the second CT data 25 can be acquired with further high accuracy. Therefore, the first CT data 23 and the second CT data 25 can be aligned with further high accuracy.

[0090] In addition, in the present embodiment, as described above, the positioning member 30 has a spherical shape as a point-symmetrical shape, and in the step of aligning, the first CT data 23 and the second CT data 25 are aligned based on the center position of the spherical positioning member 30. Since the positioning member 30 has a spherical shape, the center position of the positioning member 30 can be easily and accurately acquired. Therefore, the first CT data 23 and the second CT data 25 can be easily and accurately aligned.

[0091] In addition, in the present embodiment, as described above, in the step of performing alignment, the first distance 34 between two positioning members 30 among the three positioning members 30 in the first CT data 23 and the second distance 35 between two positioning members 30 corresponding to the first distance 34 in the second CT data 25 are acquired, and one of the first CT data 23 and the second CT data 25 is enlarged or reduced so that the first distance 34 and the second distance 35 are matched, thereby performing alignment between the first CT data 23 and the second CT data 25. Thus, even when the object magnification in the first CT data 23 and the object magnification in the second CT data 25 are different, the object magnification in the first CT data 23 and the object magnification in the second CT data 25 can be matched by enlarging or reducing one of the first CT data 23 and the second CT data 25 so that the first distance 34 and the second distance 35 are matched. Therefore, for the first CT data 23 and the second CT data 25 having different object magnifications, alignment can be performed with higher accuracy by matching the object magnifications.

[0092] In addition, in the present embodiment, as described above, the center positions of the three positioning members 30 are configured to define a plane, not to be on the same straight line. Therefore, unlike the configuration in which the positioning members 30 are arranged on the same straight line, when the first CT data 23 and the second CT data 25 are aligned based on the positioning members 30, the position of the object 40 and the angle (inclination) of the object 40 are made consistent by aligning the planes. Therefore, the first CT data 23 and the second CT data 25 can be aligned with a higher accuracy.

[0093] In addition, in the present embodiment, as described above, the following step is further included: X-ray photography is performed in a state where the positioning jig 50 provided with three positioning members 30 is arranged on the subject placing portion 61 rotating around a rotation axis orthogonal to the straight line connecting the X-ray source 2 and the detector 3, thereby acquiring the first X-ray image data 22 and the second X-ray image data 24. Thus, each of the positioning members 30 can be arranged around the subject 40 without directly fixing each of the positioning members 30 to the subject 40. Therefore, the boundary between the positioning members 30 and the subject 40 is clear, so the subject 40 can be easily visually recognized.

[0094] In addition, in the present embodiment, as described above, the positioning jig 50 is formed by a cylindrical member provided with three positioning members 30 and surrounding the periphery of the subject 40. Thus, the three positioning members 30 can be arranged to surround the periphery of the subject 40. Therefore, by using a cylindrical member, each of the three positioning members 30 can be easily arranged separately around the subject 40.

[0095] In addition, in the present embodiment, as described above, in the step of generating the second CT data 25, the first range 26a is generated so as to include the first range 26a overlapping in the axial direction of the rotation axis of the object 40 orthogonal to the straight line connecting the X-ray source 2 and the detector 3, as the overlapping range 26 overlapping with the imaging range of the first CT data 23. Thus, the first CT data 23 and the second CT data 25 generated by sequentially performing X-ray imaging in the axial direction of the rotation axis of the object 40 can be accurately aligned.

[0096] [Modifications]

[0097] The embodiments disclosed this time should be considered as illustrative in all aspects and not restrictive. The scope of the present invention is indicated by the claims rather than the description of the embodiments, and includes all changes (modifications) within the meaning and scope equivalent to the claims.

[0098] For example, in the above-described embodiment, a positioning member is arranged in the overlapping range 26 overlapping the imaging range of the first CT data 23 and the imaging range of the second CT data 25, and the first CT data 23 and the second CT data 25 are aligned based on the positioning member, but the present invention is not limited to this. For example, it is also possible to configure the alignment of three or more CT data.

[0099] For explaining the first modification Fig. 9Schematic diagram showing an example of a positioning fixture 51 and positioning members 30d and positioning members 30e for explaining the alignment of three CT data. The positioning fixture 51 is provided with three positioning members 30d belonging to the first group and three positioning members 30e belonging to the second group. The three positioning members 30d belonging to the first group are arranged at a position corresponding to an overlapping range 26c overlapping with the imaging range of the third CT data (the imaging range 27a of the third X-ray image data) and the imaging range of the fourth CT data (the imaging range 27b of the fourth X-ray image data). In addition, the three positioning members 30e belonging to the second group are arranged at a position corresponding to an overlapping range 26d overlapping with the imaging range of the fourth CT data (the imaging range 27b of the fourth X-ray image data) and the imaging range of the fifth CT data (the imaging range 27c of the fifth X-ray image data). The image processing unit is configured to perform the alignment of the third CT data and the fourth CT data based on the positioning members 30d belonging to the first group, and to perform the alignment of the fourth CT data and the fifth CT data based on the positioning members 30e belonging to the second group. In addition, the alignment of more than four CT data can also be performed using the same method as the alignment of three CT data. In addition, the relative position relationship of the three positioning members 30d belonging to the first group and the relative position relationship of the three positioning members 30e belonging to the second group can be the same or different.

[0100] In addition, in the above embodiment, the first range 26a overlapping the axial direction of the rotation axis of the object orthogonal to the straight line connecting the X-ray source and the detector is shown as an example of the overlapping range overlapping the imaging range of the first CT data (the imaging range of the first X-ray image data), but the present invention is not limited to this. Fig.10 (a) and Fig.10 (b) and Fig.11 (a) and Fig.11 As shown in (b), it is also possible to include a second range 26b that overlaps in the in-plane direction of the horizontal plane including the straight line connecting the X-ray source and the detector as an overlapping range that overlaps with the imaging range of the first CT data (the imaging range of the first X-ray image data). In addition, in the second modification, it is also possible to configure to perform alignment of three or more CT data as in the first modification. In addition, Fig.10 (a) and Fig.10 (b) and Fig.11 (a) and Fig.11 (b) shows an example of the positioning jig 52 and the positioning member 30f for explaining the positioning of four imaging ranges of CT data (four imaging ranges 28 of X-ray image data).

[0101] In the above case, the positioning member 30f is provided at a position corresponding to the second range 26b overlapping with the imaging range of the CT data in the positioning fixture 52. On the positioning fixture, at least three positioning members 30f may be arranged in the second range 26b overlapping with the imaging ranges of at least two CT data to be aligned. Fig.10 (a) and Fig.10 As shown in (b), on the positioning fixture 52, three positioning members 30f are arranged in the second range 26b overlapping with the imaging range of the two CT data to be aligned, or as shown in Fig.11 (a) and Fig.11 As shown in (b) of FIG. 5 , three positioning members 30 f are arranged on the positioning jig 52 in the second range 26 b that overlaps all of the imaging ranges of four CT data to be aligned.

[0102] In the second modification, in the step of generating the second CT data, the second range that overlaps with the imaging range of the first CT data in the in-plane direction of the horizontal plane including the straight line connecting the X-ray source and the detector is generated as an overlapping range that overlaps with the imaging range of the first CT data. Thus, the first CT data and the second CT data generated by sequentially performing X-ray imaging in the in-plane direction of the horizontal plane including the straight line connecting the X-ray source and the detector of the subject can be accurately aligned.

[0103] In addition, if Fig.12 (a) and Fig.12 As in the third variation shown in (b), the overlapping range that includes the positioning fixture 53 and overlaps with the imaging range of the first CT data can be constructed to include both a first range 26a that overlaps in the axial direction of the rotation axis of the object orthogonal to the straight line connecting the X-ray source and the detector, and a second range 26b that overlaps in the in-plane direction of the horizontal plane that includes the straight line connecting the X-ray source and the detector.

[0104] In addition, in the above-mentioned embodiment, an example is shown in which the first CT data and the second CT data are aligned based on three positioning members provided at positions corresponding to the overlapping range of the positioning fixture, but the present invention is not limited thereto. For example, the first CT data and the second CT data may be aligned based on four or more positioning members provided at positions corresponding to the overlapping range of the positioning fixture.

[0105] In addition, in the above-described embodiment, an example is shown in which the positioning member is fixedly arranged on the outer peripheral surface of the positioning fixture, but the present invention is not limited to this. For example, the positioning member may also be fixedly arranged on the inner peripheral surface of the positioning fixture. In addition, the positioning member may also be respectively embedded in at least three holes or at least three recesses formed on the positioning fixture and fixedly arranged. In addition, the positioning member may also include at least three or more recesses (spaces) having an isotropic shape formed on the positioning fixture.

[0106] In addition, in the embodiment, the positioning member has a spherical shape as an example of a point-symmetrical shape, but the present invention is not limited to this. For example, as a point-symmetrical shape, it can also be any one of a regular hexahedron shape (cubic shape), a regular octahedron shape, a regular dodecahedron shape, and a regular icosahedron shape. In addition, as long as the positioning member has an isotropic shape, it may not have a point-symmetrical shape, for example, it may also be a regular tetrahedron shape or a rotational ellipsoid shape.

[0107] In addition, in the above-mentioned embodiment, the example in which the positioning member is provided on the positioning jig is shown, but the present invention is not limited to this. For example, the positioning member may be directly fixed to the subject and provided.

[0108] In addition, in the above-described embodiment, an example is shown in which at least one of the first CT data and the second CT data is enlarged or reduced in such a manner that at least one first distance and at least one second distance are consistent with each other in the step of performing alignment, but the present invention is not limited thereto. For example, the distances between the center points of a plurality of positioning members may be obtained, and at least one of the first CT data and the second CT data may be enlarged or reduced in such a manner that the obtained distances are consistent with each other. In addition, in the step of performing alignment, it may be configured so that the first CT data and the second CT data are aligned based on the center position of the positioning member without making the first distance consistent with the second distance and without enlarging or reducing at least one of the first CT data and the second CT data.

[0109] In addition, in the above-mentioned embodiment, an example is shown in which the center positions of at least three positioning members define one plane, but the present invention is not limited to this. For example, the center positions of at least three positioning members may also be arranged on the same straight line.

[0110] In addition, in the above-described embodiment, an example is shown in which the ratio of one positioning member in the horizontal direction of the overlapping range of the imaging range of the first CT data (the imaging range of the first X-ray image data) and the imaging range of the second CT data (the imaging range of the second X-ray image data) is less than one twentieth, but the present invention is not limited to this. For example, the ratio of one positioning member in the horizontal direction of the overlapping range may be greater than one twentieth.

[0111] In addition, in the above-described embodiment, when the first distance in the first CT data and the second distance in the second CT data do not match, the image processing unit makes the subject magnification of the first CT data and the subject magnification of the second CT data match by making the first distance and the second distance match, but the present invention is not limited to this. The image processing unit may be configured as follows instead of the configuration for making the first distance and the second distance match.

[0112] For example, in the third modified example, the image processing unit 11 may be configured to obtain at least one of the measured distance between the center point of the positioning member 30a and the center point of the positioning member 30b, the measured distance between the center point of the positioning member 30a and the center point of the positioning member 30c, and the measured distance between the center point of the positioning member 30b and the center point of the positioning member 30c based on the position coordinates of the positioning member in the positioning fixture pre-measured by a contact or non-contact three-dimensional coordinate measuring device (not shown). Then, the image processing unit 11 compares the obtained measured distance between at least one center point with the first distance 34 (refer to Figure 6 ) to correct the magnification of the first CT data 23, and by making the measured distance between at least one center point obtained consistent with the second distance 35 in the second CT data 25 (refer to Figure 7 ) to correct the magnification of the second CT data 25. In addition, the measured distance between the center points of the positioning members 30 measured in advance may be stored in the storage unit 20, and the image processing unit 11 may obtain the measured distance between the center points of the positioning members 30 stored in the storage unit 20. In addition, the three-dimensional coordinate measuring device includes a contact type measuring device that makes a probe contact with a measurement object for measurement, or a non-contact type measuring device that performs measurement by irradiating a laser or the like to the measurement object.

[0113] In the third modified example, as described above, in the step of performing alignment, the first distance 34 between at least two of the at least three positioning members 30 in the first CT data 23 and the second distance 35 between at least two of the positioning members 30 corresponding to the first distance 34 in the second CT data 25 are acquired, and the measured distance between at least two of the at least three positioning members 30 acquired based on the three-dimensional coordinate measurement of the positioning members 30 is acquired, and the first CT data 23 is enlarged or reduced so that the measured distance coincides with the first distance 34, and the second CT data 25 is enlarged or reduced so that the measured distance coincides with the second distance 35, thereby performing alignment between the first CT data 23 and the second CT data 25. Thus, by aligning the first CT data 23 and the second CT data 25 having different object magnifications based on the measured distance acquired from the three-dimensional coordinate measurement device, alignment can be performed with further high accuracy.

[0114] [Style]

[0115] Those skilled in the art will appreciate that the exemplary embodiments described above are specific examples of the following aspects.

[0116] (Item 1)

[0117] A method for aligning three-dimensional image data comprises the following steps:

[0118] generating three-dimensional first CT data based on first X-ray image data, wherein the first X-ray image data is obtained by performing X-ray photography on a first portion of the object and at least three positioning members having an isotropic shape;

[0119] generating three-dimensional second CT data based on second X-ray image data, the second X-ray image data being acquired by performing X-ray imaging on a second portion including an overlapping range overlapping with the imaging range of the first CT data and including a portion of the first portion of the object, and the at least three positioning members arranged in the overlapping range; and

[0120] The first CT data and the second CT data are aligned based on the positioning member having an isotropic shape in the first CT data and the second CT data.

[0121] (Item 2)

[0122] The three-dimensional image data alignment method according to item 1, wherein the positioning member has a shape that is point-symmetrical with respect to a center of the positioning member as the isotropic shape,

[0123] In the step of performing the alignment, the first CT data and the second CT data are aligned based on the point-symmetrical shape of the positioning member.

[0124] (Item 3)

[0125] The three-dimensional image data alignment method according to item 2, wherein the positioning member has a spherical shape as the point-symmetrical shape,

[0126] In the step of performing the alignment, the first CT data and the second CT data are aligned based on the center position of the spherical positioning member.

[0127] (Item 4)

[0128] According to the three-dimensional image data alignment method of item 1, in the step of performing the alignment,

[0129] acquiring a first distance between at least two of the at least three positioning members in the first CT data, and a second distance between the at least two positioning members corresponding to the first distance in the second CT data,

[0130] At least one of the first CT data and the second CT data is enlarged or reduced so that the first distance and the second distance are consistent with each other, thereby performing alignment between the first CT data and the second CT data.

[0131] (Item 5)

[0132] According to the three-dimensional image data alignment method described in Item 1, the center positions of the at least three positioning components are respectively configured to determine a plane rather than being on the same straight line.

[0133] (Item 6)

[0134] The three-dimensional image data alignment method according to Item 1 also includes the following steps: performing X-ray photography in a state where a positioning fixture provided with the at least three positioning components is arranged on a subject mounting part that rotates around a rotation axis that is orthogonal to the straight line connecting the X-ray source and the detector, thereby acquiring the first X-ray image data and the second X-ray image data.

[0135] (Item 7)

[0136] The three-dimensional image data alignment method according to item 6, wherein the positioning jig is formed of a cylindrical member provided with the at least three positioning members and surrounding the periphery of the object.

[0137] (Item 8)

[0138] According to the three-dimensional image data alignment method described in Item 1, in the step of generating the second CT data, a first range that overlaps at least in the axial direction of the rotation axis of the object orthogonal to the straight line connecting the X-ray source and the detector is generated as the overlapping range that overlaps with the imaging range of the first CT data.

[0139] (Item 9)

[0140] According to the three-dimensional image data alignment method described in Item 1, in the step of generating the second CT data, a second range that overlaps at least in the in-plane direction of a horizontal plane including a straight line connecting an X-ray source and a detector is generated as the overlapping range that overlaps with the imaging range of the first CT data.

[0141] (Item 10)

[0142] According to the three-dimensional image data alignment method of item 1, in the step of performing the alignment,

[0143] acquiring a first distance between at least two of the at least three positioning members in the first CT data, and a second distance between the at least two positioning members corresponding to the first distance in the second CT data,

[0144] acquiring a measured distance between at least two of the at least three positioning members, which is obtained based on the three-dimensional coordinate measurement of the positioning members;

[0145] The first CT data is enlarged or reduced so that the measured distance matches the first distance, and the second CT data is enlarged or reduced so that the measured distance matches the second distance, thereby aligning the first CT data with the second CT data.

[0146] (Item 11)

[0147] An X-ray imaging device, comprising:

[0148] an imaging unit including an X-ray source for irradiating X-rays and a detector for detecting the X-rays irradiated from the X-ray source, and imaging a subject; and

[0149] an image processing unit that generates CT data based on a plurality of X-ray image data acquired by imaging at a plurality of angles at which the object and the imaging unit have different relative angles,

[0150] The image processing unit

[0151] generating three-dimensional first CT data based on first X-ray image data, wherein the first X-ray image data is obtained by performing X-ray photography of a first portion of the object and at least three positioning members having an isotropic shape by the photography unit;

[0152] generating three-dimensional second CT data based on second X-ray image data, the second X-ray image data being obtained by performing X-ray imaging by the imaging unit on a second portion including an overlapping range that overlaps with the imaging range of the first CT data and including a portion of the first portion of the subject, and the at least three positioning members arranged in the overlapping range;

[0153] The first CT data and the second CT data are aligned based on the positioning member having an isotropic shape in the first CT data and the second CT data.

[0154] (Item 12)

[0155] The X-ray imaging device according to item 11 further includes: a subject placement unit, arranged between the X-ray source and the detector, on which the subject is placed, and which rotates around a rotation axis that is orthogonal to a straight line connecting the X-ray source and the detector.

[0156] The positioning member is provided on a positioning fixture arranged on the object placement portion.

[0157] (Item 13)

[0158] The X-ray imaging apparatus according to Item 12, wherein the positioning jig is formed of a cylindrical member provided with the at least three positioning members and surrounding the periphery of the object.

Claims

1. A method for aligning three-dimensional image data, characterized in that: The steps include: generating three-dimensional first computed tomography data based on first X-ray image data, wherein the first X-ray image data is obtained by performing X-ray photography of a first portion of the object and at least three positioning members having an isotropic shape; generating three-dimensional second computed tomography data based on second X-ray image data, the second X-ray image data being obtained by performing X-ray photography of a second portion including an overlapping range that overlaps with the photography range of the first computed tomography data and including a portion of the first portion of the object, and the at least three positioning members arranged in the overlapping range; as well as Based on the positioning member having the isotropic shape in the first CT data and the second CT data, the first CT data and the second CT data are aligned.

2. The three-dimensional image data alignment method according to claim 1, wherein: The positioning member has a shape that is point-symmetrical with respect to the center of the positioning member as the isotropic shape, In the step of performing the alignment, the first computed tomography data and the second computed tomography data are aligned based on the point-symmetrical shape of the positioning member.

3. The three-dimensional image data alignment method according to claim 2, wherein: The positioning member has a spherical shape as the point-symmetrical shape, In the step of performing the alignment, the first computed tomography data and the second computed tomography data are aligned based on the center position of the spherical positioning member.

4. The three-dimensional image data alignment method according to claim 1, wherein: In the step of performing the alignment, acquiring a first distance between at least two of the at least three positioning members in the first computed tomography data, and a second distance between the at least two positioning members corresponding to the first distance in the second computed tomography data, At least one of the first CT data and the second CT data is enlarged or reduced in such a way that the first distance is consistent with the second distance, thereby performing alignment between the first CT data and the second CT data.

5. The three-dimensional image data alignment method according to claim 1, wherein: The center positions of the at least three positioning members are configured to define a plane rather than being on the same straight line.

6. The three-dimensional image data alignment method according to claim 1, wherein: The following steps are also included: X-ray photography is performed with a positioning fixture having the at least three positioning members arranged on a subject mounting portion that rotates about a rotation axis that is orthogonal to a straight line connecting an X-ray source and a detector, thereby acquiring the first X-ray image data and the second X-ray image data.

7. The three-dimensional image data alignment method according to claim 6, wherein: The positioning jig is formed of a cylindrical member provided with the at least three positioning members and surrounding the periphery of the object.

8. The three-dimensional image data alignment method according to claim 1, wherein: In the step of generating the second computed tomography data, a first range that overlaps at least in the axial direction of the rotation axis of the object orthogonal to the straight line connecting the X-ray source and the detector is generated as the overlapping range that overlaps with the imaging range of the first computed tomography data.

9. The three-dimensional image data alignment method according to claim 1, wherein: In the step of generating the second computed tomography data, a second range that overlaps at least in a plane direction of a horizontal plane including a straight line connecting an X-ray source and a detector is generated as the overlapping range that overlaps with the imaging range of the first computed tomography data.

10. The three-dimensional image data alignment method according to claim 1, wherein: In the step of performing the alignment, acquiring a first distance between at least two of the at least three positioning members in the first computed tomography data, and a second distance between the at least two positioning members corresponding to the first distance in the second computed tomography data, acquiring a measured distance between at least two of the at least three positioning members, which is obtained based on the three-dimensional coordinate measurement of the positioning members; The first CT scan data is enlarged or reduced in a manner so that the measured distance is consistent with the first distance, and the second CT scan data is enlarged or reduced in a manner so that the measured distance is consistent with the second distance, thereby aligning the first CT scan data with the second CT scan data.

11. An X-ray imaging device, characterized in that: include: an imaging unit including an X-ray source for irradiating X-rays and a detector for detecting the X-rays irradiated from the X-ray source, and imaging a subject; as well as an image processing unit that generates computed tomography data based on a plurality of X-ray image data acquired by imaging at a plurality of angles at which the object and the imaging unit have different relative angles, The image processing unit generating three-dimensional first computed tomography data based on first X-ray image data, wherein the first X-ray image data is obtained by performing X-ray photography of a first portion of the object and at least three positioning members having an isotropic shape by the photography unit; generating three-dimensional second computed tomography data based on second X-ray image data, the second X-ray image data being obtained by performing X-ray photography by the photography unit on a second portion including an overlapping range that overlaps with the photography range of the first computed tomography data and including a portion of the first portion of the subject, and the at least three positioning members arranged in the overlapping range; Based on the positioning member having the isotropic shape in the first CT data and the second CT data, the first CT data and the second CT data are aligned.

12. The X-ray imaging device according to claim 11, wherein: Also includes: The object placement unit is arranged between the X-ray source and the detector, places the object thereon, and rotates around a rotation axis that is orthogonal to a straight line connecting the X-ray source and the detector. The positioning member is provided on a positioning fixture arranged on the object placement portion.

13. The X-ray imaging device according to claim 12, wherein: The positioning jig is formed of a cylindrical member provided with the at least three positioning members and surrounding the periphery of the object.

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