JP2005270260A - Radiography apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform a correction processing for removing density non-uniformity included in an image photographed at a high speed. <P>SOLUTION: An image processing means 108 takes a combination of an imaging region, an imaging direction, and a body position as an imaging order, stores an acceptable value of information on the density non-uniformity of a radiographic image in a storage means by making the acceptable value correspond to the imaging order, reads out the acceptable value of the information on the density non-uniformity of said stored radiographic image according to the imaging order, and corrects the density non-uniformity in the radiographic image detected by an X-ray detector, using the acceptable value of the information on the density non-uniformity of the read radiographic image. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an X-ray imaging apparatus capable of imaging multiple sites including the chest and limbs with an X-ray imaging apparatus, and relates to a technique for improving an obstacle to high image quality such as a grid.

As described in [Patent Document 1], a conventional X-ray imaging apparatus acquires information on a radiographic image obtained by capturing radiation from a radiation generation apparatus through a subject and a grid. Density unevenness in the radiographic image is corrected based on correction data relating to the imaging distance between the radiation generating device and the radiation input surface of the recording medium on which the grid is placed and the radiographic image is recorded. It is possible to appropriately correct and remove density unevenness in a radiographic image that occurs when the grid focal length and the imaging distance are different during radiography.
Japanese Patent Laid-Open No. 2003-111753

However, in the above [Patent Document 1], when the sensitivity of the captured image is corrected after calculating the correction coefficient, the correction process takes time, and the time from shooting to image display increases.
In order to process cut-off correction at high speed, it is conceivable to obtain correction information in advance according to the shooting distance, the number of grids, the grid ratio, the grid focal length, and the tube voltage, and switch them. In this case, the amount of correction information is actually enormous, and a long processing time is required to find an appropriate condition from the enormous information.
In addition, if an oblique shooting element is added, the combination becomes enormous and further processing time is required.

  An object of the present invention is to provide an X-ray imaging apparatus capable of performing correction processing for removing density unevenness included in a captured image at high speed.

  In order to achieve the above object, an X-ray imaging apparatus according to the present invention includes an X-ray tube that irradiates a subject with X-rays, and an X-ray that transmits transmitted X-rays of the subject disposed opposite to the X-ray tube across the subject. An X-ray detector to detect as an image, a grid arranged between the X-ray tube and the X-ray detector to remove scattered X-rays generated by the passage of the subject, patient information of the subject, examination information, X-ray imaging conditions of the X-ray tube based on the patient information, examination information, imaging site, imaging direction, and body position of the subject input by the input means, the input means for inputting the imaging site, imaging direction, and body position, Control means for setting various conditions including image processing conditions of the X-ray image detected by the X-ray detector, and controlling to take an X-ray image of the subject according to the various conditions, the control The means is a set of the imaging region, imaging direction, and posture. The tolerance value of the density unevenness information of the X-ray image is stored in the storage means in association with the imaging order, and the stored tolerance value of the density unevenness information of the X-ray image is stored in the imaging order. The X-ray image detected by the X-ray detector is corrected using the read value of the density unevenness information of the read X-ray image.

  According to the present invention, correction processing for removing density unevenness included in a captured image can be performed at high speed.

Embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is an overview of an X-ray imaging apparatus according to an embodiment of the present invention. FIG. 2 is a diagram showing a configuration example and connection of the X-ray imaging apparatus of the present invention, and FIG. 3 is a block diagram of density unevenness correction processing of the present invention.

  FIG. 4 is a flowchart showing a method of creating a density unevenness correction image used in the density unevenness correction processing performed by the image processing means 108, and FIG. 5 is a shooting order when creating a density unevenness correction image corresponding to the shooting order. It is an example of the imaging conditions corresponding to. FIG. 6 is an example showing the characteristics of the grid corresponding to the grid ID in the photographing condition table (FIG. 5) when the density unevenness corrected image is created. FIG. 7 is an example showing the characteristics of the additional filter corresponding to the additional filter ID in the photographing condition table (FIG. 5) when the density unevenness corrected image is created. FIG. 8 is an example of a density unevenness corrected image corresponding to the photographing order, which is stored in the storage unit in the image processing unit 108.

  FIG. 9 is an example of an imaging screen displayed on the display means 202, and FIG. 10 shows the grid focusing distance and the distance from the X-ray tube focus to the X-ray detector when the density unevenness correction processing of the present invention is not applied. FIG. 11 is a view showing a captured image of the chest where density unevenness has occurred on the left and right of the image because the images were taken with different (SID). FIG. 11 shows that density unevenness was removed when the density unevenness correction of the present invention was performed. FIG. 12 is a view showing a photographed image of the chest, FIG. 12 is a view showing a photographed image of the cervical vertebra in which density unevenness has occurred due to oblique insertion when the uneven density correction processing of the present invention is not applied, and FIG. It is a figure which shows the picked-up image of the cervical vertebra from which density nonuniformity was removed when density nonuniformity correction was performed.

  FIG. 14 is a block diagram of density unevenness correction processing of the second embodiment, and FIG. 15 is a density unevenness corrected image corresponding to the photographing order stored in the density unevenness corrected image ID storage unit 1401 of the second embodiment. It is an example of ID. FIG. 16 is an example of the density unevenness corrected image corresponding to the density unevenness corrected image ID stored in the density unevenness corrected image storage unit 1402. FIG. 17 is a block diagram of density unevenness correction processing according to the third embodiment.

An overview of the X-ray imaging apparatus of the present embodiment is shown in FIG.
The X-ray imaging apparatus includes a high voltage generator 101, a main body 102, an arm 106, an X-ray detector 103, a grid 104, an X-ray image receiving unit 105, an X-ray tube device 107, an image processing means 108, and a liquid crystal monitor 109 with a touch panel. Become.
The X-ray image receiving unit 105 includes an X-ray detector 103 and a grid 104. Note that the grid 104 is detachable from the X-ray image receiving unit 105.

The main body 102 of the X-ray imaging apparatus is fixed on the floor as shown in FIG.
The arm 106 can be expanded and contracted, and the distance (SID) between the image receiving surface of the X-ray detector 103 and the X-ray tube focal point of the X-ray tube device 107 can be changed. The arm 106 can move up and down, rotate (in the plane of FIG. 1), and turn (in a plane orthogonal to the plane of FIG. 1).

  The X-ray image receiving unit 105 can move up and down, rotate, and turn. As described above, since the arm 106 and the X-ray image receiving unit 105 can be rotated independently, it is possible to perform standing-up imaging or lying-down imaging and oblique imaging. Further, since the arm 106 and the X-ray image receiving unit 105 can rotate, oblique imaging can be performed from two directions. Since the X-ray image receiving unit 105 and the arm 106 can move up and down, the height of the X-ray image receiving unit 105 can be adjusted to a position that matches the height of the patient's chin in chest standing radiography.

FIG. 2 is a diagram illustrating a configuration example and connection of the X-ray imaging apparatus. X-ray imaging apparatus includes high voltage generating means 101, X-ray tube apparatus 107, X-ray tube apparatus support means 203, X-ray image receiving section support means 204, grid 104, X-ray detector 103, input means 201, image processing means. 108, comprising display means 202.
The X-ray image receiving unit 105 includes an X-ray detector 103 and a grid 104. As the input means 201 and the display means 202, a liquid crystal monitor with a touch panel can be used.

The high voltage generating means 101 includes a high voltage generating device that generates a high voltage and a photographing switch. The high voltage generating means 101 is connected to the X-ray tube device 107 by a cable. When an engineer presses an imaging switch that is a part of the high voltage generation means 101, a high voltage is generated, and X-rays are generated in the X-ray tube device 107. The X-ray tube device 107 is supported by X-ray tube device support means 203. The X-ray tube device support means 203 is, for example, the arm 106 and the main body 102 in FIG.
Further, the X-ray image receiving unit 105 is supported by the X-ray image receiving unit supporting means 204. The X-ray image receiving unit support means 204 is, for example, the main body 102 in FIG.

  As the X-ray detector 103, a detachable portable flat panel detector (FPD) or a built-in FPD can be used. Here, the FPD includes an indirect FPD and a direct FPD. For example, an indirect FPD uses a phosphor array that converts X-rays into light (eg, CsI) and a photodiode array that two-dimensionally arranges photodiodes that convert light into electrical signals. It is an apparatus that converts an intensity distribution into a digital image.

The X-ray detector 103 is connected to the image processing means 108 with a cable or the like. In the image processing means 108, density unevenness correction, image rotation, image cut-out processing, image reduction processing, gradation processing, and the like of the present invention are performed. Then, a photographed image in which density unevenness is corrected is displayed on the display means 202.
The display unit 202 (for example, a liquid crystal monitor) displays imaging orders corresponding to a plurality of parts, and the engineer can input the imaging order to be performed by the input unit 201 (for example, touch panel).

For the image processing means 108, for example, a computer can be used. Further, the image processing means 108 includes a CPU for controlling the entire processing of the image processing means 108, a memory, a hard disk, etc., which are storage means for storing density unevenness corrected images and captured images. Yes. Further, an input unit 201 and a display unit 202 are connected to the image processing unit 108.
When the image processing means 108 is connected to a RIS server (computer), HIS server (computer), PACS server (computer), or imager that outputs a film, a network card may be incorporated.

  Further, the density unevenness correction processing of the present invention is stored as an executable program on the hard disk or the like in the image processing means 108, and is executed by the image processing means 108, for example.

  As shown in FIG. 3, the density unevenness correction processing of the present invention is used for density unevenness correction image storage means 301 for storing a density unevenness correction image corresponding to the photographing order, and density unevenness correction corresponding to the photographing order. The density unevenness correction control means (image processing means 108) for switching the density unevenness correction image and the density unevenness correction means 302 for removing the density unevenness included in the photographed image are configured.

The density unevenness corrected image storage unit 301 is, for example, a hard disk or the like in the image processing unit 108. The density unevenness correcting unit 302 is the image processing unit 108 capable of performing operations such as division.
Then, the image processing unit 108 reads out the density unevenness correction image corresponding to the imaging order from the density unevenness correction image storage unit 301 for the captured image obtained from the X-ray image receiving unit 103 and the density unevenness correction unit 302 captures the image. Density unevenness included in the image is removed.

For example, when the focusing distance of the focusing grid is 140 cm and chest imaging (SID = 180 cm) is performed (imaging order = chest (frontal PA standing)), the imaging order (imaging order) is stored in the density unevenness correction image storage unit 301. In the case of the density unevenness correction image corresponding to ID = i), for example, in the case of the chest (frontal PA standing), the density unevenness included in the photographed image is determined such that the image center is 1 and the image periphery is 0.4. The normalized image G _i (x, y) is stored. Then, the above-described density unevenness correction image G _i (x, y) is divided from the captured image I (x, y) when the imaging order is the chest (frontal PA standing), thereby obtaining a central portion of the image. The brightness unevenness corrected image O (x, y) in which the increase in brightness at the periphery of the image due to the grid cut-off is corrected is obtained. (Formula 1)

Next, FIG. 4 shows a method for creating a density unevenness correction image in the X-ray imaging apparatus.
In the air image capturing S401, in the X-ray imaging apparatus, in a dose range where the pixel value of the captured image changes linearly with respect to the dose, certain fixed imaging conditions (eg, 120 kV, 100 mA, 30 ms, SID = 180 cm, no grid, no subject), and a captured image (air image G ₀ (x, y)) is acquired.

In initialization of variable i S402, variable i is initialized to zero. Then, the variable i is incremented by 1 in the increment S403 of the variable i.
In the offset image acquisition S404, an image is acquired in a state where X-rays are not exposed (offset image).

In the acquisition S405 of the subject-free image when the imaging order ID is i, for example, the imaging conditions (SID, grid ID, tube voltage, additional filter ID, diagonal filter) when the imaging order ID is i as shown in FIG. Take an image at an angle of incidence, and obtain a captured image. For example, when the imaging order is chest (frontal PA standing) (imaging order ID = 1), the imaging conditions are SID = 180cm, grid ID = 4, tube voltage 120kV, additional filter ID = 3, oblique angle 0 ° It is.
Here, the grid ID in the imaging condition table of FIG. 5 corresponds to the grid table shown in FIG. 6, and the additional filter ID corresponds to the additional filter table as shown in FIG.

Next, in the offset correction S406 of the non-subject image and the gain correction S407 of the non-subject image, the offset image F when the X-ray is not exposed from the non-subject image G _i (x, y) ( x, y) is subtracted (offset correction), and divided by an image obtained by subtracting the offset image F (x, y) from the air image G ₀ (x, y) (gain correction). (Formula 2)

  Next, since the density unevenness included in the captured image has a low spatial frequency, the unevenness density image component is extracted by smoothing the image in the spatial smoothing S408. Here, an average value filter or the like having a kernel size of 7 pixels × 7 pixels may be used for the smoothing process.

Next, in the normalization processing S409 in which the image center is 1, the spatially smoothed captured image G ′ (x, y) that is the output image of the spatial smoothing S408 is converted into the image center ( Divide by the pixel value G ′ (0, 0) of coordinates (x, y) = (0, 0)) (Formula 3). This normalized image G ″ (x, y) is a density unevenness correction image and is used for density unevenness correction (Equation 3).

Further, the processing from the increment S403 of the variable i to the comparison processing S410 between the variable i and the maximum value M (total number of imaging orders) is performed for all imaging order IDs. The total number of photographing orders may be about 120, for example.
Here, an example of a density unevenness correction image corresponding to the photographing order is shown in FIG. Such an image is stored in the density unevenness corrected image storage unit 301 (eg, a hard disk of the image processing unit 108) before the inspection.

  Next, FIG. 9 shows an example of a shooting screen in which the shooting order is displayed on the display means 202 (eg, liquid crystal monitor). As described above, the imaging screen includes an examination information display area (examination No display field 901), a patient information display area (patient ID display field 902, patient name display field 903, gender display field 904, age display field 905, date of birth. A day display field 906), an imaging order information display area (imaging order display fields 907 and 908), an examination order display area 909 for displaying an examination order (all imaging orders of a patient), and a captured image or an uneven density correction image. There is an image display area 910 for displaying. The example of the photographing screen displayed on the display means 202 shows a state in which the chest (front PA standing) and the chest (side RL standing) are input as photographing orders.

  When a liquid crystal monitor with a touch panel is used as the input unit 201 and the display unit, for example, the imaging order is input by pressing the margin area of the inspection order display area 909 with a finger on this imaging screen. A list-displayed menu screen is displayed (not shown), and the shooting order can be input by pressing the shooting order with a finger.

On the imaging screen (FIG. 9) displayed on the display means 202, the technician performs imaging of the patient after manually or automatically selecting the imaging order to be imaged.
For example, when the imaging order of chest (frontal PA standing position) is selected, it is selected from a plurality of density unevenness correction images (FIG. 8) stored in the hard disk or the like in the image processing means 108. A density unevenness correction image corresponding to the photographing order is automatically selected by the image processing means 108 and set in the density unevenness correction means 302.

  Then, when an engineer presses an imaging switch that is a part of the high voltage generation unit 101, the X-ray detector 103 acquires a captured image. The captured image acquired by the X-ray detector 103 is transmitted to the image processing means 108 via a cable or the like.

  Here, in the case of shooting where the grid focusing distance and SID are different, density unevenness occurs in the direction perpendicular to the grid stripes in the shot image (FIG. 10). Alternatively, when X-rays are not incident perpendicularly to the image receiving surface of the X-ray detector 103 but are incident obliquely (oblique imaging), the captured image has a region close to and far from the X-ray tube focus. Density unevenness that results in non-uniform density occurs (Figure 12).

As shown in FIG. 3, the density unevenness correction processing includes density unevenness correction image storage means 301 for storing a density unevenness correction image (FIG. 8) corresponding to a photographing order prepared in advance, and density unevenness correction image storage means. Using density unevenness corrected images corresponding to the photographing order from 301, density unevenness correcting means 302 for correcting the density unevenness of the captured image is configured. Here, the density unevenness corrected image storage means 301 may be a hard disk or the like that is part of the computer that is the image processing means 108. Further, the density unevenness correcting unit 302 may be described as a division process in a program executable by the computer that is the image processing unit 108, and the division process may be performed after photographing. Actually, in the image processing means 108, the captured image I (x, y) obtained from the X-ray detector 103 is divided by the density unevenness corrected image corresponding to the imaging order read from the density unevenness corrected image storage means 301. And displayed on the display means 202. (Formula 4)

Here, the density unevenness correcting means 302 is not limited to division processing, and can be realized by table conversion processing, subtraction processing, and the like, and correction processing can be performed faster than division processing (Equation 5). In this case, using the logarithmic conversion table LUTlog for logarithmic conversion, the density unevenness corrected image G ″ (x, y) is converted into logarithm in advance, and the logarithmically converted image G ′ ″ (x, y) is corrected for density unevenness. After storing the image in the image processing means 108 as an image and converting the captured image I (x, y) obtained from the X-ray image receiving means 103 into a logarithm using the logarithmic conversion table LUTlog (logarithmically captured image), By subtracting the logarithmically converted density unevenness correction image G '''(x, y) from this logarithmically captured image and converting it to an exponent using the exponent conversion table LUTexp, a process equivalent to the division process (Formula 4) Can be realized.

The logarithmic conversion table LUTlog and the exponential conversion table LUTexp may be stored in a hard disk, a memory, or the like that is a part of the computer that is the image processing means 108.
Then, after image rotation, image cutout, image expansion / contraction, gradation processing, and the like are performed in the image processing unit 108, a captured image from which density unevenness has been removed is displayed on the display unit 202.
For example, when the grid focusing distance is 140cm and the SID is 180cm (shooting order = chest (frontal PA standing)), the result is as shown in Fig. 11. The grid focusing distance is 140cm, the SID is 150cm, and the oblique angle Is taken at 10 degrees (imaging order = front of cervical spine), an image from which density unevenness has been removed is displayed as shown in FIG.

  In the above description, the case where the imaging order is manually input from the input unit 201 is described. However, when the hospital has a radiation information system (RIS), the image processing unit 108 is connected to a network (LAN) in the hospital. By receiving patient information (patient name, patient ID, gender, date of birth, etc.), examination information (examination ID, etc.) and imaging order information (imaging order ID, etc.) delivered from the RIS server, Patient information, examination information, and imaging order may be automatically input.

  Next, a second embodiment related to density unevenness correction processing will be described. As shown in FIG. 14, the density unevenness correction process includes density unevenness corrected image ID storage means 1401, density unevenness corrected image storage means 1402, and density unevenness correction means 302. The density unevenness corrected image ID storage unit 1401 is a hard disk or the like in the image processing unit 108. The density unevenness corrected image ID storage unit 1401 stores a density unevenness corrected image ID corresponding to the photographing order as shown in FIG.

  The density unevenness corrected image storage unit 1402 is a hard disk or the like in the image processing unit 108. As shown in FIG. 16, the density unevenness corrected image storage unit 1402 stores a density unevenness corrected image according to the density unevenness corrected image ID. In this way, by performing density unevenness correction using the density unevenness corrected image ID, it is not necessary to store the same density unevenness corrected image in the density unevenness corrected image storage means 1402, so the storage capacity is small. That's it.

  Next, a third embodiment related to density unevenness correction processing will be described. As shown in FIG. 17, the density unevenness correction process includes density unevenness corrected image ID storage means 1401, density unevenness corrected image storage means 1402, switching means 1701, and density unevenness correction means 302. The density unevenness corrected image ID storage means 1401 stores the density unevenness corrected image ID for the photographing order as shown in FIG. 15 as described above. Further, as described above, the density unevenness corrected image storage unit 1402 stores a density unevenness corrected image for the density unevenness corrected image ID as shown in FIG. Then, by providing the switching means 1701, in the case of a shooting order that does not require density unevenness correction (eg, when density unevenness corrected image ID = 4 in FIG. 16), the density unevenness correction processing is not performed. Is possible. In this way, by switching whether or not to perform density unevenness correction processing according to the imaging order, in the case of a shooting order that does not require density unevenness correction, density unevenness correction is not performed, so the processing time can be shortened. it can.

  It should be noted that an image obtained by combining (eg, multiplying) the density unevenness correction image of the present invention with the sensitivity correction image for correcting the sensitivity variation for each pixel of the X-ray detector is a density unevenness corrected image storage unit 301 (1402). ) In advance, and by switching the density unevenness correction image synthesized according to the imaging order, the correction of the sensitivity variation for each pixel of the X-ray detector and the correction of the density unevenness according to the imaging order are simultaneously performed. The time from shooting to image display can be further shortened.

  In addition, when shooting under conditions that deviate significantly from the standard shooting conditions (SID, grid ID, tube voltage, additional filter ID, oblique angle) with respect to the shooting order, density unevenness is reversed due to overcorrection. May occur. For example, when the imaging order is the chest (frontal PA standing), the standard imaging conditions are a grid with a focusing distance of 140 cm (grid ID = 4), and a grid with a focusing distance of 180 cm (grid ID = When the image is photographed using 6) and the uneven density correction of the present invention is performed, the density of the peripheral portion of the image becomes dark. Therefore, the standard photographing conditions (FIG. 5) corresponding to the photographing order are stored in the hard disk or the like in the image processing means 108, and the image processing means 108 is compared with the actual photographing conditions and overcorrection occurs. It may be determined whether or not the photographing condition has been changed to such an extent that the density unevenness correction is not performed based on the determination result.

1 is an overview diagram of an X-ray imaging apparatus according to an embodiment of the present invention. The figure which showed the structural example and connection of the X-ray imaging apparatus which become embodiment of this invention. The block diagram of the density nonuniformity correction process which becomes embodiment of this invention. The figure which shows the content of the initial setting of the density nonuniformity correction process which becomes embodiment of this invention. The figure which shows the example of the imaging conditions corresponding to the imaging | photography order used when producing the density nonuniformity correction image used for the density nonuniformity correction process which becomes embodiment of this invention. FIG. 6 is a diagram showing a characteristic of a grid corresponding to a grid ID in a photographing condition (FIG. 5) when creating a density unevenness correction image according to an embodiment of the present invention. FIG. 6 is a diagram showing the characteristics of an additional filter corresponding to the additional filter ID under the photographing condition (FIG. 5) when creating a density unevenness correction image according to the embodiment of the present invention. The figure which shows the example of the density nonuniformity correction image used for the density nonuniformity correction which becomes embodiment of this invention. The figure which shows the example of the imaging | photography screen of the X-ray imaging apparatus which becomes embodiment of this invention. The schematic diagram of the picked-up image in case density | concentration nonuniformity arises when the convergence distance and SID of the conventional grid differ. The schematic diagram of the picked-up image from which the density nonuniformity was removed in the X-ray imaging apparatus which becomes embodiment of this invention. The schematic diagram of the picked-up image showing that the density nonuniformity has arisen in the area | region close | similar to a X-ray tube focus at the time of performing the conventional oblique insertion imaging | photography, and a distant area | region. FIG. 3 is a schematic diagram of a captured image that can remove density unevenness even in oblique insertion imaging in the X-ray imaging apparatus according to the embodiment of the present invention. FIG. 10 is a block diagram of density unevenness correction processing according to the second embodiment of the present invention. FIG. 10 is a diagram showing an example of density unevenness corrected image ID corresponding to a photographing order stored in density unevenness corrected image ID storage means 1401 in density unevenness correction processing according to the second embodiment of the present invention. FIG. 10 is a diagram illustrating an example of a density unevenness correction image corresponding to a density unevenness correction image ID stored in a density unevenness correction image storage unit 1402 in the density unevenness correction processing according to the second embodiment of the present invention. FIG. 10 is a block diagram of density unevenness correction processing according to a third embodiment of the present invention.

Explanation of symbols

  104 ... Grid, 105 ... X-ray image receiving means, 107 ... X-ray tube device, 108 ... Image processing means, 109 ... LCD monitor with touch panel

Claims (1)

An X-ray tube that irradiates the subject with X-rays, an X-ray detector that is disposed opposite to the X-ray tube across the subject, and detects transmitted X-rays of the subject as an X-ray image; the X-ray tube; A grid arranged between X-ray detectors for removing scattered X-rays generated by passage of the subject; input means for inputting patient information, examination information, imaging region, imaging direction, and body position of the subject; X-ray imaging conditions of the X-ray tube and image processing conditions of the X-ray image detected by the X-ray detector based on the patient information, examination information, imaging region, imaging direction, and body position of the subject input by the means An X-ray imaging apparatus comprising: a control unit configured to set various conditions including and control to capture an X-ray image of the subject according to the various conditions;
The control means stores the allowable value of density unevenness information of the X-ray image in the storage means in association with the imaging order using the combination of the imaging region, imaging direction, and body position as the imaging order, and stores the stored X The allowable value of the density unevenness information of the line image is read according to the imaging order, and the X-ray image detected by the X-ray detector is read using the read density unevenness information of the X-ray image. An X-ray imaging apparatus characterized by correcting density unevenness.

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