JP2005211550A - X-ray imaging apparatus, image processing system, image processing method, storage medium, program - Google Patents

Abstract

In a standing CBCT type X-ray image photographing apparatus that performs white correction such as FPD, a problem of omitting a step of moving a subject support mechanism out of a photographing region when photographing a white image is solved. In addition, the problem that the subject support mechanism appears in the captured image even after white correction is solved.
In an X-ray imaging apparatus provided with a two-dimensional planar radiation detection means, an image imaging means that is calibrated with a reference white image, a subject turntable for rotating a subject, and a subject on the turntable A subject support means for fixing, a rotation angle detection means for detecting a rotation angle of the turntable at the time of photographing each image, and a database storage means for linking and storing the angle information obtained by the rotation angle detection means and each captured image. Thus, in the white correction at the time of shooting the subject image, the white correction is performed by using the white image having the same subject rotation angle.
[Selection] Figure 1

Description

  The present invention relates to an X-ray imaging apparatus, an image processing system, an image processing method, a storage medium, and a program using a semiconductor photoelectric conversion element. In particular, the present invention relates to an X-ray imaging apparatus capable of performing standing CBCT (cone beam CT) imaging, an image processing system, an image processing method, a storage medium, and a program.

  In a conventional X-ray imaging apparatus, an X-ray beam is projected from an X-ray source through an object to be analyzed such as a medical patient, and after the X-ray beam passes through the subject, a screen film cassette, a film autochanger, CR (Computed radiography) And FPD (Flat Panel Detector).

  In X-ray photography, a high-resolution solid-state X-ray detector using FPD has been proposed. This is a two-dimensional array using photoelectric conversion elements represented by 3000 to 4000 photodiodes in each dimension. It has a configured X-ray sensor. Each photoelectric conversion element creates an electrical signal corresponding to the amount of X-rays projected on the X-ray sensor. Thereby, a subject is placed between the X-ray source and the X-ray sensor, and an X-ray image of the subject is obtained by converting the X-ray dose transmitted through the subject into an electrical signal. Further, signals from the respective photoelectric conversion elements are individually read out and digitized, and thereafter image processing, storage and display are performed.

  FIG. 11 is a conceptual diagram showing a system using such a radiographic image capturing apparatus. In FIG. 11, reference numeral 1101 denotes an X-ray image capturing apparatus incorporating an X-ray detection sensor 1102. The subject 1104 is fixed and rotated by the subject support means 1108 to the subject rotation means 1109. The subject 1104 is irradiated with X-rays emitted from the X-ray generator 1103, and X-rays transmitted through the subject are detected by photoelectric conversion elements arranged in a two-dimensional lattice pattern on the X-ray detection sensor 1102. The image signal output from the detection element is subjected to digital image processing by the image processing means 1105, and an X-ray image of the subject is displayed on the monitor 1106.

  FIG. 3 is a diagram showing a conventional white correction process. The sensitivity of the X-ray detection sensor 1102 is slightly different for each pixel. The process for correcting this sensitivity difference and obtaining uniform characteristics is white correction. In conventional white correction processing, a white image is created by irradiating the X-ray detection sensor 1102 with substantially uniform X-rays. Each photographed image is white-corrected by regarding the white image as if the X-ray distribution is uniform.

In order to make the white image an image in which the sensitivity difference of each pixel is correctly reflected, the X-ray transmittance is in-plane between the X-ray detection sensor 1102 and the X-ray generation device 1103 when photographing the white image. There should be no foreign material distributed. This is because when a foreign object is present at the time of photographing a white image, a reverse image of the shadow of the foreign object is mixed into a subsequent captured image. In the conventional white correction processing, a white image showing a sensitivity distribution for each pixel can be created by observing the above-mentioned attention when acquiring a white image. In Patent Documents 1 and 2, the effectiveness of a white image is determined from the above viewpoint. Using the white image determined to be valid, white correction is performed on the subject image taken by subject shooting. This white correction corrects a subtle sensitivity difference for each pixel, and the X-ray detection sensor 1102 performs imaging as a sensor with uniform sensitivity.
JP 2001-351091 A JP 2000-070261 A

  However, in a standing CBCT imaging apparatus using FPD, when imaging is performed by rotating the human body with a turntable, an error due to body movement at the time of the CT reconstruction is prevented. A human body support mechanism was required. This human body support mechanism has a problem that, when a white image is captured, the inverted image is mixed in each captured image unless it is moved out of the imaging region.

  In addition, when the white image is photographed, the human body support mechanism is reflected in the subject photographed image when moved outside the photographing region.

  That is, the first problem is to omit the step of moving the human body support mechanism outside the imaging region. The second problem is to correct the human body support mechanism from appearing in the captured image.

  The present invention solves both problems simultaneously. That is, it solves the problem of preventing the human body support mechanism from appearing in the image by white correction in each image without removing the human body instruction mechanism.

  It is an object of the present invention to provide a standing CBCT type X-ray imaging apparatus that can correct a human body support mechanism such as a backrest by synchronizing the rotation angles of a captured image and a white image in a standing CBCT type X-ray imaging apparatus. A line image photographing device, an image processing device, an image processing system, an image processing method, a program for realizing or implementing any of them, and a computer-readable storage medium storing the program are provided.

  As a means for solving the above-mentioned problem, in the X-ray imaging apparatus according to the first aspect of the invention, in the X-ray imaging apparatus including the two-dimensional planar radiation detection means, calibration is performed with a reference white image. Image pickup means, a subject turntable for rotating the subject, a subject support means for fixing the subject to the subject turntable, a rotation angle detection means for detecting a rotation angle of the turntable at the time of each image shooting, and the rotation It has database storage means for linking and storing angle information obtained by the angle detection means and each captured image.

  The X-ray imaging apparatus according to claim 2 is characterized in that the rotation angle of the white image and the rotation angle of the captured image are the same.

  An X-ray imaging apparatus according to a third aspect of the invention is characterized in that the rotation angle detecting means is an encoder.

  In the X-ray imaging apparatus according to the fourth aspect of the invention, the white image is an image obtained by adding a plurality of white images having the same rotation angle.

  The X-ray imaging apparatus according to claim 5 is characterized in that an average of rotation angles of the plurality of white images is the same as a rotation angle of the captured image.

  The X-ray imaging apparatus according to claim 6 is characterized in that the width of the rotation angle of the white image is equal to or less than the width of the rotation angle of one frame at the time of subject imaging.

  The X-ray imaging apparatus according to claim 7 is characterized in that the rotational speed of the rotating table when capturing the white image is different from the rotational speed when capturing the subject image.

  The X-ray imaging apparatus according to an eighth aspect of the invention is characterized in that the turntable rotates at a constant speed when each image is captured.

  The X-ray imaging apparatus according to claim 9, wherein the white image and the captured image are images obtained without rotation of the turntable, and the rotation of the white image The angle is the same as the rotation angle of the captured image.

  An image processing system according to a tenth aspect of the present invention is an image processing system in which a plurality of devices are communicably connected to each other, and at least one of the plurality of devices is defined by the first to ninth aspects. It has the function of the image processing apparatus in any one of these.

  In the image processing method according to the eleventh aspect of the present invention, the angle information obtained by the rotation angle detection means and the image linked to each captured image_storing in each rotation angle database, based on the database, The method includes a step of white correcting an image captured by the imaging unit using a white image captured at the same rotation angle.

  In a storage medium according to a twelfth aspect of the present invention, there is provided a program for causing a computer to realize the function of the image processing apparatus according to any one of the first to ninth aspects or the function of the image processing system according to the eleventh aspect. The recorded computer is readable.

  According to a thirteenth aspect of the present invention, a storage medium according to the thirteenth aspect of the present invention is readable by a computer recording a program for causing a computer to execute the processing steps of the image processing method according to the eleventh aspect.

  According to a fourteenth aspect of the present invention, there is provided a program for causing a computer to realize the function of the image processing apparatus according to any one of the first to ninth aspects or the function of the image processing system according to the eleventh aspect. .

  According to a fifteenth aspect of the present invention, there is provided a program that causes a computer to execute the processing steps of the image processing method according to the eleventh aspect.

  As described above, according to the present invention, the above-described object can be achieved.

  Hereinafter, the present invention will be described in detail based on the embodiment shown in FIGS. In the text, the white image and the gain image have the same meaning. White correction and gain correction have the same meaning. Further, the rotation position and the rotation angle in the text have the same meaning.

  The present invention is applied to, for example, an X-ray imaging apparatus 1000 as shown in FIG. In particular, the X-ray imaging apparatus 1000 according to the present embodiment fixes and rotates a subject by a subject support mechanism in an X-ray image, acquires X-ray images in continuous frames, performs image processing such as white correction, and the like. It is configured to display a reconstructed image or the like. Next, the configuration and operation of the X-ray imaging apparatus 1000 of this embodiment will be specifically described.

  As shown in FIG. 1, the X-ray imaging apparatus 1000 includes an X-ray generation circuit 1001 that generates X-rays, a two-dimensional X-ray sensor 1005 that detects X-rays 1002 transmitted through a subject 1003, and two-dimensional X-rays. The image capturing unit 1010 that captures image data output from the sensor 1005, a subject support mechanism 1021 that supports and fixes the subject 1003, a subject rotation unit 1004, and a rotation angle detection unit 1008, and obtained rotation The angle is stored in each image_rotation angle: database 1011. Instructions for operations for each of them are X-ray imaging execution instructions and various operations for performing various settings on the apparatus 1000 via the operation panel 1012, an X-ray condition setting means 1006, a rotation control means 1007, It is set by the image capturing mode setting means 1009 or the like. White correction means 1007 for performing white correction on the image data collected by the image capturing means 1010, main memory 1016 for storing various information such as image data and processing programs for executing various processes, and various image processing An image processing means 1019 for performing image processing, an image reconstruction means 1018 for creating a CT reconstructed image using a plurality of images, and a CPU 1008 for controlling the operation of the entire apparatus 1000. The image capturing means 1010, image processing The circuit 1019, the image display means 1020, the CPU 1015, the main memory 1016, the white correction means 1017, the image reconstruction means 1018, and the operation panel 1012 are connected to each other via a CPU bus 1014 so that they can communicate with each other.

  FIG. 2 is a flowchart showing the operation of the X-ray imaging apparatus 1000. When the operation according to the flowchart of FIG. 2 is performed, for example, the main memory 1009 stores data and processing programs necessary for executing various processes in the CPU 1008 and is used as a working memory (work memory) for the CPU 1008. However, in particular, the processing program according to the flowchart of FIG. 2 is stored as a processing program for image processing according to the present embodiment. Therefore, the CPU 1008 reads out and executes an image processing program (a processing program according to the flowchart of FIG. 2) from the main memory 1009, thereby performing an X described below according to an operation from the operation panel 1010. Control for the operation of the line imaging apparatus 1000 is performed.

  Step S201: The X-ray generation circuit 1001 emits an X-ray beam 1002 in order to obtain a white image without the subject (inspected object) 1003. At this time, the subject support unit 1021 is rotated by the subject rotation unit 1004, and a rotated image can be obtained without the subject 1003 alone. The subject support means 1021 exists in the photographing range of the white image, and the subject support means 1004 at each rotation angle is arranged in the white image. The X-ray beam 1002 emitted from the X-ray generation circuit 1001 reaches the two-dimensional X-ray sensor 1005. The two-dimensional X-ray sensor 1005 outputs image data indicating sensitivity information of each pixel of the two-dimensional X-ray sensor 1005. Since the main image is an image of only the subject support means without a subject, it is used as a white image used for white correction. The obtained white image is stored in the main memory 1016. While the subject instruction mechanism is rotating, the rotation angle detection means 1008 such as an encoder creates each rotation angle at the time of capturing each image as a database. This is repeated at least a specified number of times of one or more rotations so as to avoid the influence of graininess in the white image and to obtain a uniform white image. The obtained white image is stored in the main memory 1009.

  Step S202: A white image used for white correction is created by adding the white images obtained in the previous step. In the first embodiment, each white image to be added is a white image having the same rotation angle as the captured image. A white image for each rotation angle is created. In each white image, the subject instruction means 1021 is shown with the rotation angle changed. The obtained white image added for each angle is stored in the main memory 1009. Further, the obtained white image is stored in each image_rotation angle database in the same manner as each other white image.

  Step S203: An X-ray image of the subject is taken. A subject 1003 is fixed by a subject support unit 1021 and rotated by a subject rotation unit 1004 to be photographed. The rotation speed, the image capture mode, the X-ray conditions, and the like are preferably the same when shooting a white image and when shooting a subject. However, the present invention is also applicable to shooting conditions such as Embodiment 2 and Embodiment 3 described later. The purpose of is achieved.

  Steps S204 to S206: Reference is made to each image_rotation angle database. A subject image and a gain image are selected at each rotation angle of the subject image, and a white image corresponding to the subject image and the rotation angle is selected.

  Step S207: Division is performed using a pair of a subject image and a gain image whose rotation angle is a common term, and white correction is performed. According to the method of the first embodiment, since the rotation angle of the white image and the subject image is the same, the subject support unit 1006 or the like is not captured in the image after the white correction. In addition, since it is not necessary to remove the subject support means outside the image area when photographing a white image, the step of photographing a white image can be omitted.

  In the present specification, the angle is described as being the same, but the scope claimed in the present invention is not limited to the same angle. For example, as in the first embodiment, when the subject photographing image and the white image are driven by the same rotation device and the image capturing unit is the same, a part of the file name or a part of the image number is set to the angle. To be linked to. It is also included in the scope of the present invention to perform white correction by selecting each white image so that part of the file name linked to the angle or part of the image number is the same. Needless to say.

  FIG. 4 is a diagram comparing the method of this embodiment with a conventional method. FIG. 4A is a schematic diagram of a shooting area at the time of shooting each image. FIG. 4B is a schematic diagram of a typical example of each image. The top, bottom, left, and right of FIGS. 4A and 4B are schematic diagrams in each state. The upper left is the state when shooting the subject image in the present invention, the lower left is the state when shooting the subject image in the conventional method, the upper right is the state when shooting the white image in the present invention, and the lower right is the state when shooting the white image in the conventional method. Is shown.

  From FIG. 4 (a), it can be seen that the difference between the present invention and the conventional method is the presence / absence of a back support when photographing a white image. That is, it is shown that the effects of the present invention can be obtained, such as eliminating the troublesomeness of removing the back supporter when photographing a white image.

  From FIG. 4B, by dividing the white image and the photographed image, the back support appears in the image in the conventional method, whereas in the method of the present invention, the back support is obtained by white correction. It turns out that it is erased from inside.

  FIG. 5 is a diagram showing white image shooting using rotation angle information in the first embodiment. The upper and lower parts in FIG. 5 show the correspondence between the rotation speed of the subject rotating means 1004 and the time and the X-ray irradiation time when “subject image” is captured and when “white image” is captured.

  The upper graph in FIG. 5 is a graph showing the correspondence between the rotation speed of the subject rotation unit 1004, the time, and the X-ray irradiation time when “subject image” is captured. The area of the lattice portion in the graph represents the number of rotations that the subject rotation means 1004 has rotated during X-ray irradiation.

  At the time of photographing a subject image, X-ray irradiation requires about one rotation (about 1/2 rotation) in order to reduce the exposure dose of X-rays and create a CT reconstructed image. When the image capture is fixed, the subject needs to rotate at a constant speed when X-rays are irradiated.

  The number of rotations during X-ray irradiation will be described. In order to suppress the exposure dose to the subject, the rotation amount during the X-ray irradiation is about 1 rotation (about 1/2 rotation). Actually, there is a possibility that (I) a temporal change in X-ray irradiation, (II) a time lag such as a trigger at the time of image capturing, (III) rotation unevenness of the subject rotation means 1004, etc. Needs to be rotated slightly more at the time of X-ray irradiation than one rotation (about 1/2 rotation). Empirically, in order to obtain an X-ray image that can absorb these errors, it is sufficient to capture an X-ray image that has been rotated by about 5%. For example, to obtain an image of one rotation (360 °), it is sufficient to obtain an image of 1.05 rotation (378 °).

  The lower graph of FIG. 5 is a graph showing the correspondence between the rotation speed of the subject rotation means 1004 and the time and the X-ray irradiation time when “white image” is captured. In the first embodiment, the rotation control unit 1007 is set with the same setting when shooting “white image” and when shooting “subject image”. Also, the X-ray irradiation conditions and the image capture conditions are the same. This is because it is possible to suppress factors that cause white correction errors by arranging various environments. It is the best mode that the rotation control conditions, the X-ray irradiation conditions, and the image capturing conditions of the first embodiment are made the same in white image shooting and subject image shooting.

  FIG. 6 is an example of each image_rotation angle database in the case of the first embodiment. For each file, the rotation position and rotation angle of each image obtained from the rotation angle detection means such as an encoder can be referred to. In FIG. 6, the presence / absence of backrest and the image type can be referred to on the database at the same time as information as attached information. In addition to storing these information as a database, for example, a method of enabling identification by a file name may be used. The same applies to the rotation angle and rotation position in the sense that they are incorporated into the file name. That is, the file name is ******. It is included in each image_rotation angle database in the broad sense of the present invention that the rotation angle of an image with dcm is defined as 0.00 ° to 0.35 ° so that the rotation angle of each image can be grasped. Shall be.

  FIG. 7 shows an example of the operation screen 1010 when white correction is performed by the method of the present embodiment. For example, if you answer Yes to the message “Do you want to correct white based on the rotation angle synchronized with the rotation angle_image database?”, The method of this embodiment will correct white, The human body support means is white corrected. If the answer is No, for example, human body support means such as a backrest is subjected to white correction using a white image that is reflected in the image.

  FIG. 8 is a diagram illustrating white image shooting using rotation angle information in the second embodiment. The difference from the first embodiment is the instruction content of the rotation control means 1007 for the subject rotation means 1004 when shooting a white image. In principle, exactly the same rotation control instruction is desirable when photographing the “subject image” and when photographing the “white image” as in the first embodiment. However, in essence, it is sufficient that the subject support means can correct correctly at each rotation of the X-ray irradiation. In this embodiment, from this point of view, rotation is performed a plurality of times at the same speed as when “subject image” is shot, and X-rays are continuously exposed during that time. And the rotation angle at the time of each image acquisition is grasped, and based on this, white correction is performed as in the first embodiment. Compared with the first embodiment, the number of exposures for white image shooting is small, and when the waiting time between the shootings is included, the time until the white image shooting is completed is an advantage of the second embodiment.

  As in the second embodiment, attention should be paid to the rise characteristic of the X-ray and the like when the rotation control support is different between the “subject image” photographing and the “white image” photographing. X-rays are generated when a filament (not shown) is heated and a constant voltage is applied between the two electrodes to accelerate the electron flux and the electrons collide with the anode target. Therefore, the amount of X-ray exposure may not be constant for about 0.1 seconds after X-ray exposure. Since the white image is an image for correcting the distribution of sensitivity for each pixel, it is desirable to avoid using a white image in which the amount of X-ray exposure is not constant.

  Next, the condition setting of the embodiment at the time of photographing a white image will be described. This is because the total amount of dose of the white image at a certain rotation angle may be reduced in the white image as in the method of the present embodiment. First, the influence of the white image dose on the white correction effect will be described, and then an example of the total amount of white image dose in this embodiment will be given. In diagnostic X-ray imaging, in order to reduce the exposure dose as much as possible, imaging is performed using an extremely small dose of X-rays. In such a minute dose of X-rays, X-rays behave as particles, and thus X-ray quantum granularity is observed. In the white correction in the FPD, the white correction is performed by regarding the non-uniform graininess as uniform. In order to reduce the influence of the non-uniform graininess in the white image, it is necessary to increase the total dose of white image shooting and to flatten the white image grain. In particular, when measuring the performance at a high dose, it is possible to prevent the granularity of the white image from being mixed into the captured image by increasing the total dose in the white image.

  In this embodiment, the subject photographed image is photographed at about one rotation (or about half rotation). In order to prevent the granularity of the white image from being visually seen in the photographed image, it is necessary that the white image be formed with a dose higher than that of the subject photographed image. From the viewpoint of eliminating graininess in the white image, it is desirable to take as much dose as possible. As a specific best mode, the subject indicating means is rotated five times or more at the same generated dose as that of the subject photographing. This number of 5 rotations has no meaning, and it is desirable to create a white image using the total amount of dose as much as possible within the limits of memory and the like, and correct the white.

  FIG. 9 is a diagram showing white image shooting using rotation angle information in the third embodiment. The difference from the first and second embodiments is the rotational speed of the subject turntable during white image shooting. Assuming that the rotation speed at the time of shooting “subject image” in FIG. 9A is V [rotation / s], the rotation speed at the time of shooting “white image” is V / n [rotation / s] (where n = 1, 2, 3, ...). The reason why the rotation speed at the time of “white image” shooting must be 1 / n times the rotation speed at the time of “subject image” shooting is that the subject supporting means at the time of “subject image” shooting at the time of “white image” shooting This is to reflect the rotation correctly.

  In the third embodiment, the rotation angle corresponding to one frame at the time of shooting a subject image corresponds to the rotation angle of n frames at the time of shooting a white image. Since the rotation speed is constant, if the image capture time is continuous, the rotation of the subject support means at the time of capturing the “subject image” is correctly reflected by capturing the continuous image of n frames. While the turntable is rotated a plurality of times (for example, M rotations), n frames × M rotations of white images are obtained for one image at the time of photographing the subject image. In the present embodiment, these are added to obtain a white image at each angle.

  The advantage of the third embodiment when compared with the first or second embodiment is that when a white image is captured at a fine angle, the rotation angle of the captured image deviates due to some influence. This is because there is a possibility that it can also be adjusted. In addition, when compared to the first or second embodiment, there is an advantage that there is no subject instruction means having a rotation angle corresponding to the time when there is a time during which X-rays cannot be captured between frames. There is a possibility of an error during white correction.

  The reason why the image capturing condition is the same as that at the time of photographing the subject image is that the X-ray detection sensor 1005 using the FPD changes the image capturing condition such as the accumulation time, so that the amount of dark current is changed. This is because it may change. This is the reason why the image capturing conditions are all the same in the first to third embodiments.

  FIG. 10 shows each image_rotation angle database in the case of the third embodiment. FIG. 10 shows a case where n = 2 in FIG. In order to correct white for a rotation angle of 0.00 ° to 0.35 ° of the subject photographed image, a white image with a rotation angle of 0.00 ° to 0.17 ° and a rotation angle of 0.18 ° to 0.35 ° The white images are added to create a white image with a rotation angle of 0.00 ° to 0.35 °. In the present embodiment, white images at a plurality of rotation angles are added as described above to create a corresponding white image. In such a case, it is a necessary condition that “the center of the rotation angle of the plurality of white images” is equal to “the center of the rotation angle of the photographed image” to be white corrected. The reason for this is that if the center of the rotation angle is deviated, white correction cannot be performed by the method of this embodiment, but the reverse image is mixed in the image and the method of this embodiment cannot be used. It is. Further, it is necessary that the rotation angle of the turntable during the acquisition of the plurality of white images is equal to or less than the rotation angle of one frame at the time of shooting the subject. The reason for this is that if the rotation angle of one frame at the time of the white image is larger than that at the time of shooting the subject image, the subject support means having an excessive rotation angle is reflected in the white image. This is because the shadows are mixed.

  In addition, what is claimed in the present invention is that the rotation speed at the time of photographing a white image is different, but the best mode is a speed of 1 / n times.

  FIG. 12 is a diagram illustrating a configuration in which imaging is performed with the backrest (subject support means) attached when the standing CBCT type X-ray imaging apparatus is used for general chest imaging of a still image. The standing CBCT type X-ray imaging apparatus can be used as a still image imaging apparatus when the subject rotation means 1109 is not rotated. In the case of still image shooting that is the fourth embodiment, a similar problem occurs in white correction. In other words, unless the backrest (subject instruction means) is moved, the backrest (subject instruction means) is captured in the still image. Removing the backrest every time a still image is taken is cumbersome. In order to solve this problem, the backrest can be erased by white correction by using a white image having the same rotation angle in the present invention even during still image shooting. In particular, in order to take advantage of the advantage that both the standing CBCT and the standing still image can be taken with one imaging apparatus, which is an advantage of the present X-ray imaging apparatus, every time the imaging setting is changed, the back support is performed. The effect of eliminating the work of moving the is great.

  Note that an object of the present invention is to supply a storage medium storing software program codes for realizing the functions of the apparatus according to the first to fourth embodiments to the system or apparatus, and the computer of the system or apparatus (or Needless to say, this can also be achieved by the CPU and MPU) reading out and executing the program code stored in the storage medium. In this case, the program code itself read from the storage medium realizes the functions of the first to fourth embodiments, and the storage medium storing the program code and the program code constitute the present invention. It becomes. As a storage medium for supplying the program code, ROM, flexible disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD-R, magnetic tape, nonvolatile memory card, and the like can be used. Further, by executing the program code read by the computer, not only the functions of the first to fourth embodiments are realized, but also an OS running on the computer based on the instruction of the program code. Needless to say, the present invention includes a case where the functions of the first and second embodiments are realized by performing part or all of the actual processing. Further, after the program code read from the storage medium is written to a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, the function expansion is performed based on the instruction of the program code. A case where the CPU or the like provided in the board or the function expansion unit performs part or all of the actual processing and the functions of the first to fourth embodiments are realized by the processing is also included in the embodiment of the present invention. Needless to say.

  Further, as shown in FIG. 13, the X-ray imaging apparatus according to the present invention can be used with a similar configuration by inserting it into a universal arm, C-arm, cassette holder or the like as a gantry.

  Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist thereof.

  Another object of the present invention is to supply a storage medium (or recording medium) in which a program code of software that realizes the functions of the above-described embodiments is recorded to a system or apparatus, and the computer (or CPU or CPU) of the system or apparatus. Needless to say, this can also be achieved by the MPU) reading and executing the program code stored in the storage medium. In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the storage medium storing the program code constitutes the present invention. Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also an operating system (OS) running on the computer based on the instruction of the program code. It goes without saying that a case where the function of the above-described embodiment is realized by performing part or all of the actual processing and the processing is included.

  Furthermore, after the program code read from the storage medium is written into a memory provided in a function expansion card inserted into the computer or a function expansion unit connected to the computer, the function is determined based on the instruction of the program code. It goes without saying that the CPU or the like provided in the expansion card or the function expansion unit performs part or all of the actual processing and the functions of the above-described embodiments are realized by the processing.

It is a figure which shows the function structure of this invention. It is a figure which shows the white correction process of this invention. It is a figure which shows the conventional white correction process. It is a conceptual diagram which shows comparison with this invention and a prior art example. It is a figure which shows white image photography (1st Example) using rotation angle information. It is a figure which shows each image_rotation angle database (in the case of a 1st, 2nd Example). It is a figure explaining an example of the operation screen which selects white correction | amendment using rotation angle information. It is a figure which shows white image photography (2nd Example) using rotation angle information. It is a figure which shows white image photography (3rd Example) using rotation angle information. It is a figure which shows each image_rotation angle database (3rd Example). It is a figure which shows the structure of the conventional standing CBCT type | mold X-ray imaging device. In the present invention, when a standing CBCT type X-ray imaging apparatus is used for still image chest general imaging, it is a diagram showing a configuration for performing still image imaging with a backrest (subject support means) attached. FIG. It is the figure which showed the example of the various imaging system which can attach and install the FPD detector of a standing CBCT type | mold X-ray imaging device.

Explanation of symbols

1000 X-ray imaging system 1001 X-ray generation circuit 1002 X-ray beam 1003 Subject 1004 Subject rotation means 1005 Two-dimensional X-ray sensor 1006 X-ray condition setting means 1007 Rotation control means 1008 Rotation angle detection means 1009 Image capture mode setting means 1010 Image Capture means 1011 Each image_rotation angle: database 1012 operation means 1013 system control means 1014 CPU bus 1015 CPU
DESCRIPTION OF SYMBOLS 1016 Main memory 1017 White correction means 1018 Image reconstruction means 1019 Image processing means 1020 Image display means S201 Gain image acquisition S202 Gain image creation for each rotation angle S203 Subject image acquisition S204 Reference to each image_rotation angle database S205 Subject image selection ( by rotation angle)
S206 Gain image selection (by rotation angle)
S207 Division S301 Gain image acquisition S302 Subject image acquisition S303 Division 1101 X-ray imaging device 1102 X-ray sensor unit 1103 X-ray generation device 1104 Subject 1105 Control unit 1106 Display unit 1107 Standing stand 1108 Back support (Subject support means)
1109 Subject rotation means 1109 Rotation angle detection means

Claims (15)

In an X-ray imaging apparatus provided with a two-dimensional planar radiation detection means,
An image capturing means that is calibrated with a reference white image;
A subject turntable for rotating the subject,
Subject support means for fixing the subject to the turntable;
Rotation angle detection means for detecting the rotation angle of the turntable at the time of each image shooting,
Database storage means for linking and storing the angle information obtained by the rotation angle detection means and each captured image;
An X-ray imaging apparatus characterized by comprising: The rotation angle of the white image and the rotation angle of the captured image are the same;
The X-ray imaging apparatus according to claim 1. The rotation angle detection means is an encoder;
The X-ray imaging apparatus according to claim 1. The white image is an image obtained by adding a plurality of white images having the same rotation angle;
The X-ray imaging apparatus according to claim 1. The average of the rotation angle centers of the plurality of white images is the same as the rotation angle center of the captured image.
The X-ray imaging apparatus according to claim 4. The width of the rotation angle of the white image is equal to or less than the width of the rotation angle of one frame at the time of subject shooting;
The X-ray imaging apparatus according to claim 4. The rotational speed of the rotating table when capturing a white image is different from the rotational speed when capturing a subject image;
The X-ray imaging apparatus according to claim 1. The turntable rotates at a constant speed when each image is captured;
The X-ray imaging apparatus according to claim 1. The white image and the captured image are images obtained without rotation of the turntable, and
The rotation angle of the white image is the same as the rotation angle of the captured image;
The X-ray imaging apparatus according to claim 1. An image processing system in which a plurality of devices are communicably connected to each other,
An image processing system, wherein at least one of the plurality of devices has the function of the image processing apparatus according to claim 1. An image processing method for outputting an image of an X-ray imaging apparatus provided with a two-dimensional planar radiation detection means,
An image for linking the angle information obtained by the rotation angle detection means and each captured image_stored in each rotation angle database;
Based on the database, a step of white correcting an image taken by the imaging means using a white image taken at the same rotation angle;
An image processing method comprising:   A computer-readable storage medium storing a program for causing a computer to realize the function of the image processing apparatus according to claim 1 or the function of the image processing system according to claim 11.   A computer-readable storage medium storing a program for causing a computer to execute the processing steps of the image processing method according to claim 11.   The program for making a computer implement | achieve the function of the image processing apparatus in any one of Claims 1-9, or the function of the image processing system of Claim 11.   The program for making a computer perform the process step of the image processing method of Claim 11.

Images