JP2018179711A - X-ray inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an X-ray inspection device that can create an X-ray transparent image of only an area necessary for reconstructing CT images.SOLUTION: An image acquisition unit 71 is configured to acquire a reference image for determining a visual field missing area and an image of a workpiece to be trimmed, from an X-ray detector 3. An average luminance value calculation unit 72 is configured to calculate an average luminance value of images having no visual field missing area in the reference image. A visual field missing area determination unit 73 is configured to determine, as the visual field missing area, an image having luminance less than a threshold of the average luminance value calculated by the average luminance value calculation unit 72 for the photographed transparent image. A trimming image acquisition unit 75 is configured to acquire an X-ray transparent image other than the visual field missing area from images obtained by photographing the workpiece. A reconstruction processing unit 8 is configured to reconstruct a CT image on the basis of the X-ray transparent image other than the visual field missing area.SELECTED DRAWING: Figure 1

Description

  An embodiment of the present invention relates to an X-ray examination apparatus in which a lack of visual field does not occur around a photographed image.

  The X-ray inspection apparatus comprises an X-ray irradiation source, a table on which an inspection object (hereinafter referred to as a workpiece) is placed, and an X-ray detector for receiving X-rays transmitted through the workpiece. The X-rays emitted from the irradiation source spread conically to reach the workpiece, and after passing through the workpiece, further spread to reach the X-ray detector. The x-rays decay in proportion to the square of the distance from the x-ray source to the detector (FDD: Focus to Detector Distance). On the other hand, the imaging magnification of the CT image is a value obtained by dividing FDD by the distance from the X-ray source to the center of the sample table on which the object to be imaged is placed (FCD: Focus to Center Distance). Therefore, in order to capture a desired CT image with a desired imaging magnification and a high dose and a high S / N, the FDD and FCD may be reduced while maintaining the imaging magnification.

JP, 2016-118394, A

  However, when the FDD is made smaller, there is a lack of field due to the X-ray irradiation angle, that is, a range in which X-rays are not irradiated to the detector. The field of vision is more likely to occur with larger detectors. When there is a lack of visual field, the following problems occur in capturing a CT image.

(1) Reconstruction of a CT image requires information on where on the detector a straight line connecting the X-ray source and the center of the sample table. When this information is obtained from the symmetry (0 ° to 180 ° and 180 ° to 360 °) of the X-ray fluoroscopic image taken from the 360 ° direction, the missing part of the visual field may be disturbed and the case may not be obtained correctly. is there. The lack of the field of view has substantially constant luminance, so the symmetry is good, which greatly affects the original judgment of the symmetry of the fluoroscopic image.

(2) Even when the straight line connecting the X-ray source and the center of the sample table is correctly found and the CT image can be reconstructed, a missing field of vision appears in the circumferential direction of the CT image after reconstruction processing, and the X-ray irradiation angle It becomes an X-ray fluoroscopic image and a CT image that include unnecessary portions other than the above. Therefore, the following problems occur in image processing.

Example 1: When it is desired to automatically extract an object to be imaged from a CT image, the average luminance value of the object is often used as a threshold, but the region of the visual field lacking region may be regarded as the object.
Example 2: When creating three-dimensional data from a CT image, since there is a missing field in the circumferential direction of the CT image, it becomes three-dimensional data in which the missing field is visible to the outside.

  As described above, when the irradiation angle is wider than the light receiving area of the detector, the whole area of the light receiving area falls within the irradiation range of X-rays even if the detector is brought close to the X-ray source. However, if the irradiation angle is narrow, reducing the FDD causes various problems associated with the lack of visual field. Therefore, conventionally, when a small FDD is required, such as when the object to be inspected is small and requires a large magnification ratio, the field of vision is lost by using a small detector dedicated to the small FDD without using a large detector. Was trying not to get up.

  Further, as described in Patent Document 1, trimming a part of an image captured by X-ray is known as such, but in these conventional techniques, the user extracts a desired region from the captured image. It was only a thing, and it could not be applied to elimination of the visual field loss in the case of reducing the FDD of the detector.

  The present embodiment is proposed to solve the problems of the prior art as described above. An object of the present embodiment is to provide an X-ray examination apparatus capable of creating an X-ray fluoroscopic image of only a region necessary for reconstruction of a CT image.

The X-ray inspection apparatus of the first embodiment has the following configuration.
(1) An X-ray irradiation source, a table on which an object to be irradiated is placed, and an X-ray detector which receives X-rays transmitted through the object to be irradiated and detects a transmission image thereof.
(2) A shift mechanism for moving the X-ray detector along the optical axis of the X-ray.
(3) A control unit that controls the movement of the X-ray detector by the shift mechanism.
(4) An image acquisition unit that acquires, from the X-ray detector, a reference image for determining a visual field lacking area and an image of a workpiece to be trimmed.
(5) An average luminance value calculation unit that calculates an average luminance value of an image without a lack of visual field in a reference image.
(6) A missing field area determining unit that determines a pixel having a brightness less than the threshold value of the average brightness value calculated by the average brightness value calculating unit as a missing field region of a captured X-ray fluoroscopic image.
(7) A trimming image acquisition unit that acquires an X-ray fluoroscopic image other than the visual field loss area determined by the visual field loss area determination unit from the image obtained by imaging the workpiece as an image of the trimming area.
(8) A reconstruction processing unit that reconstructs a CT image based on the X-ray fluoroscopic image of the trimming area acquired by the trimming image acquisition unit.

The following configuration may be adopted in the first embodiment.
(1) A boundary adjustment unit that adjusts the boundary between the non-visual-field loss area determined by the non-visual-field loss area determination unit and the area other than the visual-field loss area in the image obtained by photographing the workpiece.

The X-ray inspection apparatus of the second embodiment has the following configuration.
(1) An X-ray irradiation source, a table on which an object to be irradiated is placed, and an X-ray detector which receives X-rays transmitted through the object to be irradiated and detects a transmission image thereof.
(2) A shift mechanism for moving the X-ray detector along the optical axis of the X-ray.
(3) A control unit that controls the movement of the X-ray detector by the shift mechanism.
(4) An image acquisition unit that acquires, from the X-ray detector, a reference image for determining a visual field lacking area and an image of a workpiece to be trimmed.
(5) A setting value acquisition unit which reads the following data previously input by the user.
(1) X-ray irradiation angle (α)
(2) Detector pitch (mm / detector channel)
(3) Reference FDD (L1)
(6) A reference irradiation range calculation unit which determines the irradiation range in the reference FDD (L1) as the reference irradiation range (W1) based on the X-ray irradiation angle (α) and the reference FDD acquired from the setting value acquisition unit.
(7) A shooting position irradiation range calculation unit which calculates the irradiation range (W2) at an arbitrary FDD position (L2) by the following equation 1 based on the values obtained from the setting value acquisition unit and the reference irradiation range calculation unit .
Formula 1: Irradiation range to be determined (W2) = reference irradiation range (W1) × (arbitrary FDD (L2) / reference FDD (L1))
(8) A trimming area calculation unit which calculates a trimming area by calculating the number of channels of the detector corresponding to the irradiation range (W2) calculated by the photographing position irradiation area calculation unit according to the following equation 2.
Formula 2: Trimming area = irradiated area (W2) / detector pitch (mm) at arbitrary FDD
(9) A trimming image acquisition unit that acquires an X-ray fluoroscopic image of a trimming area calculated by the trimming area calculation unit from an image obtained by imaging a workpiece.
(10) A reconstruction processing unit that reconstructs a CT image based on the X-ray fluoroscopic image of the trimming area acquired by the trimming image acquisition unit.

The following configuration may be adopted in the second embodiment.
(1) A storage unit that stores trimming regions in a plurality of FDDs determined by the trimming region calculation unit in association with each FDD.
(2) The trimming image acquisition unit reads out the corresponding trimming area from the storage unit in accordance with the FDD of the imaging part of the workpiece, and acquires the X-ray fluoroscopic image of the trimming area.

FIG. 1 is a block diagram showing an entire configuration of a first embodiment. The figure which shows an example of the X-ray fluoroscopic image in which the visual field lack area | region in 1st Embodiment was contained. The block diagram which shows the whole structure of 2nd Embodiment. FIG. 13 is a view for explaining a method of determining a missing field in the third embodiment.

[1. First embodiment]
[1-1. Configuration of embodiment]
The first embodiment will be specifically described below with reference to the drawings. In the first embodiment, trimming is performed using a threshold set in advance for the luminance of a fluoroscopic image.

  As shown in the plan view of FIG. 1, the X-ray inspection apparatus of the present embodiment receives an X-ray beam emitted from the X-ray tube 1 which is a radiation source, a table 2 on which a workpiece is placed, and the X-ray tube 1. The X-ray detectors 3 are arranged at predetermined intervals.

  The X-ray tube 1 emits a conical X-ray beam in the horizontal direction from its focal point, and the X-ray beam passes through the work placed on the table 2 and reaches the X-ray detector 3. The table 2 is rotated about an axis in the vertical direction or moved in a direction parallel to the moving direction of the X-ray tube 1 and the moving direction of the X-ray detector 3 by a rotary table or an XY driving mechanism (not shown). .

  The X-ray detector 3 detects an X-ray beam with a two-dimensional spatial resolution, and outputs data for displaying a transmission image on a display or a film. The X-ray inspection apparatus captures an image of a workpiece by stopping the X-ray detector 3 at a predetermined FDD position determined according to the dimensions of the workpiece and the required imaging magnification. Therefore, the X-ray detector 3 is connected with the shift mechanism 4 as a drive source for movement, and the control unit 5 for controlling the movement direction and movement amount of the X-ray detector 3 by the shift mechanism 4. The control unit 5 moves the X-ray detector 3 in the direction of moving along the optical axis of the X-ray tube 1, that is, in the direction in which the FDD changes. The control unit 5 is provided with an input unit 6 for the user to set in advance the movement position and movement direction of the X-ray detector 3. The input unit 6 can be composed of an input device such as a keyboard and a mouse, and an external device such as a network.

  The X-ray detector 3 is provided with a trimming processing unit 7 that removes a missing portion of the visual field from the image captured at the stop position. The trimming processing unit 7 of the present embodiment includes an image acquisition unit 71, an average luminance value calculation unit 72, a visual field lack area determination unit 73, a boundary adjustment unit 74, and a trimming image acquisition unit 75.

  The image acquisition unit 71 acquires, from the X-ray detector 3, a reference image for determining a missing field of vision and an image of a workpiece to be trimmed. The reference image is an X-ray fluoroscopic image that does not show anything. The average luminance value calculation unit 72 calculates the average luminance value in the central part of the image without lack of view in the reference image, for example, within the dotted line frame in FIG. The visual field lack area determination unit 73 determines a pixel having a luminance less than a predetermined% of the average luminance value calculated by the average luminance value calculation unit 72 as the visual field lack area for the captured fluoroscopic image. The predetermined% of the average luminance value is a threshold value by which the pixel can be determined to belong to the visual field lack area, and the user sets the value in the trimming processing unit 7 from the input unit 6 in advance.

  Since it is considered that the boundary between the visual field lack area and the visual field missing area performed by the visual field lack area determination unit 73 in a pixel unit is jagged, the boundary adjusting part 74 adjusts the visual field lack area to be a quadrilateral. The adjustment method can employ | adopt the conventionally well-known method suitably. For example, the reference image is set as two-dimensional coordinates of XY, and a straight line in the X and Y directions passing through the maximum value or the minimum value of the coordinates of the pixel determined to be a visual field missing area is an outer edge of the area without visual field missing.

  The trimming image acquisition unit 75 acquires an X-ray fluoroscopic image other than the missing field area obtained by the boundary adjustment unit 74 from the image obtained by imaging the workpiece. The output side of the trimming image acquisition unit 75 is provided with a reconstruction processing unit 8 for reconstructing a CT image based on the X-ray fluoroscopic image other than the missing field of vision.

  In each of the above-mentioned units, the data input from the input unit 6, the data of the image read by the detector 3, the calculation result of the trimming processing unit 7 and the data of the determined visual field lack area etc. Part 9 is connected. The storage unit 9 is configured of a storage device such as a memory or a hard disk.

[1-2. Operation of embodiment]
In the present embodiment, the FDD of the imaging position of the workpiece W is input from the input unit 6, and the control unit 5 controls the shift mechanism 4 based on the FDD to stop the detector 3 at the input FDD. . In this state, an X-ray fluoroscopic image without any image is taken. In this way, a fluoroscopic image having a central part of the image without a lack of visual field as shown in FIG. 2 and a lack of visual field region formed around it can be obtained. Usually, since the X-ray fluoroscopic image that does not show anything is a fluoroscopic image of the air at the central part of the image (the upper right slanted hatched part in FIG. 2) without lack of visual field, the peripheral visual field missing area (cross hatched part in FIG. The luminance is large compared to the above, and the luminance is almost zero since the X-ray is not received in the non-field of view.
The fluoroscopic image of FIG. 2 is output from the detector 3 to the image acquisition unit 71. The average luminance calculation unit 72 calculates an average luminance value of the central portion of the image without lack of visual field from the fluoroscopic images input to the image acquisition unit 71. The visual field lack area determination unit 73 determines, for the captured fluoroscopic image, a pixel having an average luminance value calculated by the average luminance calculation unit 72 and a luminance smaller than a threshold set by the user from the input unit 6 in advance The portion of the pixel is regarded as a missing field area.

  The boundary adjustment unit 74 adjusts the boundary between the non-field of the view and the non-field without the field performed by the field-of-view missing area determination unit 73 on a pixel basis to be a square. In this embodiment, a reference image is set as two-dimensional coordinates of XY, and a straight line in the X and Y directions passing through the maximum value or the minimum value of the coordinates of the pixel determined to be a missing area is an outer edge of the area without missing field. The coordinates of the missing field or the field without missing field thus obtained are stored in the storage unit 9 together with the corresponding FDD.

(2) Photographing of Workpiece W When photographing the workpiece W, the detector 3 is stopped at the position of the FDD where the coordinates of the missing area of the field of vision or the area without field missing are obtained as described above. In this state, the work W is placed on the table 2 and an X-ray fluoroscopic image is taken. The X-ray fluoroscopic image detected by the detector 3 is output to the trimming image acquisition unit 75. The trimming image acquisition unit 75 reads the coordinates corresponding to the FDD of the stop position of the detector 3 from the storage unit 9, and based on this coordinate position, an image other than the missing field in the X-ray fluoroscopic image of the work W get.

  The X-ray fluoroscopic image other than the missing field area obtained by the trimming image acquisition unit 75 is output to the reconstruction processing unit 8, and the reconstruction processing unit 8 performs CT based on the X-ray fluoroscopic image without the missing field area. The image is reconstructed.

[1-3. Effect of embodiment]
The present embodiment has the following effects.
(1) Since an image can be reconstructed on the basis of an X-ray fluoroscopic image without a missing field of vision, it is possible to obtain an appropriate CT image according to the actual state of the workpiece W.
(2) Whatever the size of the detector 3 or FDD, it is always possible to perform CT imaging with an optimal X-ray fluoroscopic image.

(3) The X-ray fluoroscopic image and the CT image with no loss of field are obtained even when the X-ray geometrical magnification is enlarged by bringing the detector 3 close to the X-ray generator side.
(4) If the detector 3 is stopped by the FDD by associating the FDD and the image of the visual field loss region in the storage unit 9, the work W can be determined without determining the visual field loss region each time. It is possible to obtain a fluoroscopic image without a missing field of vision from an X-ray fluoroscopic image taken of
(5) Since the boundary adjusting section 74 adjusts the boundary between the visual field lack area and the visual field absence area in the pixel unit to be a quadrangle, X-ray fluoroscopy with no visual field missing area with a well-defined outer edge You can get an image.

[2. Second embodiment]
[2-1. Configuration of embodiment]
The second embodiment is different from the first embodiment in the configuration of the trimming processing unit 7, and the other configurations are the same as those in the first embodiment. About the same composition as a 1st embodiment, the same numerals are attached and explanation is omitted.

  The trimming processing unit 7 of the second embodiment includes a set value acquisition unit 76, a reference irradiation range calculation unit 77, a photographing position irradiation range calculation unit 78, and a trimming area calculation unit 79.

The setting value acquisition unit 76 reads the following data input by the user to the setting unit 6 in advance (see FIG. 3).
(1) X-ray irradiation angle (α)
(2) Detector pitch (mm / detector channel)
(3) Reference FDD (L1) (FDD in which the irradiation range and the light receiving surface of the detector coincide and no loss of vision occurs)

The reference irradiation range calculation unit 77 uses the irradiation range in the reference FDD (L1) as the reference irradiation range (W1) based on the X-ray irradiation angle (α) and the reference FDD (L1) acquired from the setting value acquisition unit 76. Ask. The imaging position irradiation range calculation unit 78 uses the similarity of the triangle based on the values known by the setting value acquisition unit 76 and the reference irradiation range calculation unit 77 to use the irradiation range (W2) at an arbitrary FDD position (L2). ) Is obtained by the following equation.
Formula 1: Irradiation range to be determined (W2) = reference irradiation range (W1) × (arbitrary FDD (L2) / reference FDD (L1))

The trimming area calculation unit 79 calculates a trimming area by calculating which channel the detector corresponds to the determined irradiation area (W2) with the following equation.
Formula 2: Trimming area = irradiated area (W2) / detector pitch (mm) at arbitrary FDD

[2-2. Operation of embodiment]
In the second embodiment, prior to photographing of the work W, the following values are input from the input unit 6 and stored in the storage unit 9. Since these values are unique to the X-ray imaging apparatus to which the second embodiment is applied, they may be set once, and there is no need to input each time the work W is imaged.
(1) X-ray irradiation angle (α)
(2) Detector pitch (mm / detector channel)
(3) Reference FDD (L1)

  Next, to capture an X-ray fluoroscopic image of the workpiece W, the detector 3 is moved to the position of the FDD to be captured. The movement of the detector 3 inputs the FDD (L2) of the photographing position of the work W from the input unit 6, and the control unit 5 controls the shift mechanism 4 based on this FDD to input the detector 3 into the FDD. Stop at position. Also, as in the case of moving the detector 3 manually, when the FDD at the imaging position is not known in advance, in the state where the detector 3 is stopped at the imaging position, the FDD is automatically or manually taken. Are set in the input unit 6 as FDD (L2) of

  By doing this, the values necessary to execute Equations 1 and 2 can be obtained. The set value acquisition unit 76 of the trimming processing unit 7 reads these values, and in the reference irradiation range calculation unit 77, The reference irradiation range (W1) which is the irradiation range in the reference FDD (L1) is determined. This reference irradiation range, once calculated, has the same value even if the FDD at the imaging position is different, unless the light receiving area of the detector 3 or the X-ray irradiation angle is changed. Depending, by the next time calculation is unnecessary.

  Based on the value obtained as described above, the imaging position irradiation range calculation unit 78 calculates the irradiation range (W2) in the FDD (L2) of the imaging position of the workpiece W based on Expression 1. Subsequently, based on these values, the trimming area calculation unit 79 obtains a trimming area based on Expression 2.

  In this state, an X-ray fluoroscopic image of the work W is taken, and from the image, only the image of the portion corresponding to the trimming area determined as described above, that is, the irradiation range (W2) in FDD (L2) By extracting X, it is possible to take an X-ray fluoroscopic image that does not include a missing field in the periphery.

  In the second embodiment, the calculation of the trimming area and the photographing of the X-ray fluoroscopic image of the workpiece W may be performed by storing each data in the storage unit 9 and reading out the data appropriately. good.

[2-3. Effect of embodiment]
In addition to the effects common to the first embodiment, the second embodiment has the following specific effects.

(1) In the second embodiment, the geometry is determined from the X-ray irradiation angle (α) as shown in FIG. 3, the size of the detector obtained from the reference irradiation range (W1), and the information (L1, L2) of the FDD. The region to be trimmed can be easily determined by scientific calculation.

(2) In the second embodiment, since the fluoroscopic image of the air is captured in advance at the position where the workpiece is captured as in the first embodiment and the calculation of the trimming area by the threshold of the luminance is not necessary, the determination of the trimming area is It can be implemented quickly and easily. In addition, since the boundary between the non-visual-field region and the non-visual-field region is also formed in a straight line, calculation for adjusting the boundary is not necessary, which is also advantageous.

[3. Third embodiment]
The third embodiment is a modification of the second embodiment. As shown in FIG. 3, by the method of the second embodiment, trimming areas (W2, W3, W4) as reference are determined by a plurality of FDDs (L2, L3, L4) expected to capture the work W. It is registered in the storage unit 9.

  At the time of photographing of the work W, the X-ray fluoroscopic image is photographed by moving the detector 3 to the area of the FDD most suitable for photographing the work from among a plurality of FDD registered in the storage unit 9, and trimming corresponding to the FDD The area is used to delete a missing portion of the field of view from the fluoroscopic image taken. On the other hand, when there is no FDD optimum for photographing the work W in the registered FDD, that is, when photographing at an arbitrary FDD position, the closest FDD value registered in the storage unit 9 and the corresponding trimming area Use the value of to find the trimming area at any position from the similarity of triangles.

  As described above, in the third embodiment, the X-ray fluoroscopic image of the air is taken at positions where the field of view is largely lacking and not missing, and positions (multiple positions possible) between them, and areas to be trimmed are determined and registered. . Since the trimming area increases or decreases according to the geometrical system, the trimming area at a position not captured is obtained by interpolation.

In the third embodiment, trimming regions of a plurality of imaging locations are stored in advance in association with the FDD of each imaging location, and an appropriate trimming region is called according to the FDD of the imaging position of the workpiece W to perform X-ray fluoroscopy. It is possible to delete the missing field area in the image. As a result, it is not necessary to calculate the trimming area each time moving to a new FDD, and it is possible to obtain an X-ray fluoroscopic image without a missing field of view quickly. In addition, even with respect to FDD in which the trimming area is not registered, accurate trimming area can be obtained by simple calculation by geometrically interpolating according to FDD.
[4. Other embodiments]
The present invention is not limited to the above embodiment, and at the implementation stage, the components can be modified and embodied without departing from the scope of the invention. In addition, various inventions can be formed by appropriate combinations of a plurality of constituent elements disclosed in the above embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, components in different embodiments may be combined as appropriate. Specifically, the following other embodiments are also included.

(1) The X-ray tube 1, the table 2 and the X-ray detector 3 may be arranged in the vertical direction, in addition to being arranged in parallel with the mounting surface of the X-ray inspection apparatus.
(2) The X-ray detector 3 is not limited to a flat plate orthogonal to the optical axis of X-rays, and may have a light receiving surface curved about an X-ray focal point.
(3) In the first embodiment, as in the third embodiment, the X-ray fluoroscopic image of the air is taken at the position where the field of view is largely missing and the position where it is not missing, and the position (multiple positions possible) between them. An area to be stored may be obtained and registered in the storage unit 9. In that case, since the trimming area increases or decreases according to the geometric system, the trimming area registered in the storage unit 9 is used as the imaging position of the workpiece W for the trimming area at the position where the X-ray fluoroscopic image of air is not captured. Calculated by interpolation according to the FDD position of.

DESCRIPTION OF SYMBOLS 1 ... X-ray tube 2 ... Table 3 ... X-ray detector 4 ... Shift mechanism 5 ... Control part 6 ... Input part 7 ... Trimming process part 71 ... Image acquisition part 72 ... Average brightness value calculation part 73 ... A field missing area determination part 74: boundary adjustment unit 75: trimming image acquisition unit 76: setting value acquisition unit 77: reference irradiation range calculation unit 78: shooting position irradiation range calculation unit 79 ... trimming area calculation unit 8: reconstruction processing unit 9: storage unit

Claims (4)

An X-ray inspection apparatus comprising: an X-ray irradiation source; a table on which an object to be irradiated is placed; and an X-ray detector which receives X-rays transmitted through the object and detects a transmission image thereof.
A shift mechanism for moving the X-ray detector along an optical axis of the X-ray;
A control unit that controls movement of the X-ray detector by the shift mechanism;
An image acquisition unit for acquiring from the X-ray detector a reference image for determining a visual field lacking area and an image of a workpiece to be trimmed;
An average luminance value calculation unit that calculates an average luminance value of the image without a lack of visual field in the reference image;
A visual field loss area determination unit that determines a pixel having a brightness less than the threshold of the average brightness value calculated by the average brightness value calculation section as the visual field loss area for the X-ray fluoroscopic image taken;
A trimming image acquisition unit configured to acquire, as an image of a trimming area, an X-ray fluoroscopic image other than the vision loss area determined by the vision loss area determination unit from an image obtained by imaging the workpiece;
An X-ray examination apparatus comprising: a reconstruction processing unit configured to reconstruct a CT image based on the X-ray fluoroscopic image of the trimming area acquired by the trimming image acquisition unit.   The X-ray inspection apparatus according to claim 1, further comprising: a boundary adjustment unit that adjusts the boundary between the non-visual-field loss area determined by the non-visual-field loss area determination unit and the area other than the non-visual-field loss area in the image obtained by photographing the workpiece. An X-ray inspection apparatus comprising: an X-ray irradiation source; a table on which an object to be irradiated is placed; and an X-ray detector which receives X-rays transmitted through the object and detects a transmission image thereof.
A shift mechanism for moving the X-ray detector along an optical axis of the X-ray;
A control unit that controls movement of the X-ray detector by the shift mechanism;
An image acquisition unit for acquiring from the X-ray detector a reference image for determining a visual field lacking area and an image of a workpiece to be trimmed;
A setting value acquisition unit that reads the following data input by the user in advance;
(1) X-ray irradiation angle (α)
(2) Detector pitch (mm / detector channel)
(3) Reference FDD (L1)
A reference irradiation range calculation unit which determines an irradiation range in the reference FDD (L1) as a reference irradiation range (W1) based on the X-ray irradiation angle (α) and the reference FDD acquired from the setting value acquisition unit;
An imaging position irradiation range calculation unit which calculates an irradiation range (W2) at an arbitrary FDD position (L2) according to the following equation 1 based on values obtained from the setting value acquisition unit and the reference irradiation range calculation unit;
Formula 1: Irradiation range to be determined (W2) = reference irradiation range (W1) × (arbitrary FDD (L2) / reference FDD (L1))
A trimming area calculation unit which calculates a trimming area by calculating the number of channels of the detector corresponding to the irradiation range (W2) calculated by the photographing position irradiation area calculation unit according to the following equation 2;
Formula 2: Trimming area = irradiated area (W2) / detector pitch (mm) at arbitrary FDD
A trimming image acquisition unit for acquiring an X-ray fluoroscopic image of the trimming area calculated by the trimming area calculation unit from an image obtained by photographing the workpiece;
An X-ray examination apparatus comprising: a reconstruction processing unit configured to reconstruct a CT image based on the X-ray fluoroscopic image of the trimming area acquired by the trimming image acquisition unit. And a storage unit that stores trimming regions in the plurality of FDDs determined by the trimming region calculation unit in association with the respective FDDs,
4. The X-ray examination apparatus according to claim 3, wherein the trimming image acquisition unit reads the corresponding trimming area from the storage unit according to the FDD of the imaging part of the workpiece to acquire an X-ray fluoroscopic image of the trimming area.

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