Patent Publication Number: US-2018028138-A1

Title: Medical image processing apparatus and medical image processing method

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     The present application claims priority under 35 U.S.C. §365 to International Patent Application No. PCT/KR2016/001804 filed Feb. 24, 2016, which claims priority to Korean Patent Application Nos. 10-2015-0025909, filed Feb. 24, 2015 and 10-2016-0018544, filed Feb. 17, 2016, each of which are incorporated herein by reference into the present disclosure as if fully set forth herein. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to medical image processing apparatuses and medical image processing methods, and more particularly, to a medical image processing apparatus and a medical image processing method for displaying image information and correcting an image. 
     BACKGROUND 
     In general, X-rays are electromagnetic waves having a wavelength of 0.01 to 100 Å and can pass through an object. Thus, they may be commonly used in a wide range of applications, such as medical equipment that take images of the inside of a living body and non-destructive testing equipment for industrial use. 
     X-ray imaging apparatuses using X-rays allow X-rays emitted by an X-ray source to pass through an object, and detect a difference between the intensities of the passed X-rays from an X-ray detector to thereby acquire an X-ray image of the object. X-ray imaging apparatuses also easily identify the internal structure of an object based on an X-ray image of the object and diagnose a disease of the object. 
     SUMMARY 
     According to an aspect of exemplary embodiment, there is provided a medical image processing apparatus comprising: a processor configured to acquire a first image and a second image captured by radiating an X ray to an object, generate a synthesis image by overlapping a first region of the first image with a second region of the second image, and determine matching accuracy representing a degree to which the first region and the second region match with each other; and a display configured to display the matching accuracy and the synthesis image. 
     According to an aspect of exemplary embodiment, there is provided a An X-ray imaging apparatus comprising: a source configured to radiate an X-ray to an object; a detector configured to detect an X-ray transmitted by the object; a processor configured to control a location of at least one of the source and the detector, acquire an image captured based on the location of the source and the location of the detector, and acquire error information of the captured image due to a location error of at least one of the source and the detector from the captured image; and a display configured to display information about correction of the at least one location error, based on the captured image and the error information of the captured image. 
     Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments. 
     Medical image processing apparatuses capture and synthesize a plurality of images and display information of matching accuracy of the plurality of images. The medical image processing apparatuses may provide a more accurate image by correcting a mismatched region of an overlapped region between the images. 
     X-ray imaging apparatuses allow for correction of a location error thereof via a user interface (UI) screen image, simplify a correction procedure, and enhance the quality of image. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and/or other aspects will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings in which: 
         FIG. 1  is a schematic diagram of an X-ray system according to an embodiment; 
         FIG. 2  is a perspective view of a fixed type X-ray apparatus according to an embodiment; 
         FIG. 3  is a schematic diagram of a mobile X-ray apparatus according to an embodiment; 
         FIG. 4  is a schematic diagram showing a detailed configuration of a detector according to an embodiment; 
         FIG. 5  explains a result of synthesizing a plurality of images having an overlapped region, according to an embodiment; 
         FIG. 6A  is a block diagram of a structure of a medical image processing apparatus according to an embodiment; 
         FIG. 6B  is a block diagram of a structure of a medical image processing apparatus according to another embodiment; 
         FIG. 7A  is a flowchart of a medical image processing method according to an embodiment; 
         FIG. 7B  is a flowchart of a medical image processing method according to another embodiment; 
         FIG. 8  explains a method of synthesizing a plurality of images captured according to locations on an object, according to an embodiment; 
         FIG. 9A  explains a screen image that is output to a medical image processing apparatus and displays matching accuracy, according to an embodiment; 
         FIG. 9B  explains a screen image that is output to a medical image processing apparatus and displays matching accuracy, according to another embodiment; 
         FIG. 10A  explains a user interface (UI) screen image via which a medical image processing apparatus corrects a synthesis image, according to an embodiment; 
         FIG. 10B  explains a UI screen image via which a medical image processing apparatus corrects a synthesis image, according to another embodiment; 
         FIG. 11  explains an operation of an X-ray imaging apparatus according to an embodiment; 
         FIG. 12A  is a block diagram of a structure of an X-ray imaging apparatus according to an embodiment; 
         FIG. 12B  is a block diagram of a structure of an X-ray imaging apparatus according to another embodiment; 
         FIG. 13  is a flowchart of a method of operating an X-ray imaging apparatus, according to an embodiment; 
         FIG. 14  explains a structure of an X-ray imaging apparatus according to an embodiment; 
         FIG. 15A  explains a photographing operation of an X-ray imaging apparatus according to an embodiment; 
         FIG. 15B  illustrates a synthesis image generated by an X-ray imaging apparatus; 
         FIG. 16A  explains a photographing operation of an X-ray imaging apparatus according to an embodiment; 
         FIG. 16B  illustrates a synthesis image generated by an X-ray imaging apparatus; 
         FIG. 17A  is a flowchart of a method of operating an X-ray imaging apparatus, according to another embodiment; 
         FIG. 17B  is a flowchart of a method of operating an X-ray imaging apparatus, according to another embodiment; 
         FIG. 18A  explains a method of correcting a location error by using a plurality of captured images via a UI screen image, according to an embodiment; 
         FIG. 18B  explains a method of correcting a location error by using a plurality of captured images via a UI screen image, according to another embodiment; 
         FIG. 19  explains a synthesis image in which location error correction of an X-ray imaging apparatus has been reflected, and a synthesis image in which location error correction of an X-ray imaging apparatus has not yet been reflected, according to an embodiment; 
         FIG. 20A  explains a method of correcting a location error by using a plurality of captured images via a UI screen image, according to another embodiment; 
         FIG. 20B  explains a synthesis image in which location error correction of an X-ray imaging apparatus has been reflected, and a synthesis image in which location error correction of an X-ray imaging apparatus has not yet been reflected, according to an embodiment; 
         FIG. 21  is a flowchart of a method of operating an X-ray imaging apparatus, according to an embodiment; 
         FIGS. 22A and 22B  explain a method of correcting a location error by using a captured image via a UI screen image, according to an embodiment; 
         FIG. 23  is a flowchart of a method of operating an X-ray imaging apparatus, according to an embodiment; and 
         FIG. 24  explains a method of correcting a location error by using a captured image via a UI screen image, according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     According to an aspect of exemplary embodiment, there is provided a medical image processing apparatus comprising: a processor configured to acquire a first image and a second image captured by radiating an X ray to an object, generate a synthesis image by overlapping a first region of the first image with a second region of the second image, and determine matching accuracy representing a degree to which the first region and the second region match with each other; and a display configured to display the matching accuracy and the synthesis image. 
     According to an aspect of exemplary embodiment, there is provided a An X-ray imaging apparatus comprising: a source configured to radiate an X-ray to an object; a detector configured to detect an X-ray transmitted by the object; a processor configured to control a location of at least one of the source and the detector, acquire an image captured based on the location of the source and the location of the detector, and acquire error information of the captured image due to a location error of at least one of the source and the detector from the captured image; and a display configured to display information about correction of the at least one location error, based on the captured image and the error information of the captured image. 
     A medical image processing apparatus comprises a processor configured to acquire a first image and a second image captured by radiating an X ray to an object, generate a synthesis image by overlapping a first region of the first image with a second region of the second image, and determine matching accuracy representing a degree to which the first region and the second region match with each other; and a display configured to display the matching accuracy and the synthesis image. 
     The display displays at least one of information about a length of an overlapped region between the first image and the second image on the synthesis image and information about a location of the overlapped region on the synthesis image. 
     The display displays, on the synthesis image, a marker indicating a location of an overlapped region between the first image and the second image. 
     The display displays information representing whether matching between the first image and the second image has succeeded, based on the matching accuracy. 
     When the first region of the first image and the second region of the second image do not match with each other, the display distinguishably displays a predetermined portion corresponding to a mismatched region between the first region of the first image and the second region of the second image. 
     The display displays, together with the synthesis image, a marker indicating a location of an overlapped region between the first image and the second image, and the processor distinguishably sets at least one of a color, shape, and pattern of the marker, based on the matching accuracy. 
     A medical image processing apparatus further comprises an input unit configured to receive a user input for correcting a range of at least one of the first region of the first image and the second region of the second image, wherein the processor corrects the range of the at least one of the first region and the second region, based on the user input, and re-generates a synthesis image by using a result of the correction. 
     The user input comprises at least one of an input of correcting a section of the overlapped region and an input of adjusting a magnification ratio of the first image or the second image. 
     The processor receives first location information representing a location of a detector for detecting an X-ray transmitted by the object during capturing of the first image, and receives second location information representing a location of the detector during capturing of the second image, determines the first region of the first image and the second region of the second image based on the first location information and the second location information, and overlaps the first region with the second region to generate the synthesis image. 
     A medical image processing method comprises acquiring a first image and a second image captured by radiating an X ray to an object; generating a synthesis image by overlapping a first region of the first image with a second region of the second image; determining matching accuracy representing a degree to which the first region and the second region match with each other; and displaying the matching accuracy and the synthesis image. 
     The displaying of the matching accuracy information and the synthesis image comprises: displaying, together with the synthesis image, a marker indicating a location of an overlapped region between the first image and the second image; and distinguishably setting at least one of a color, shape, and pattern of the marker, based on the matching accuracy. 
     When the first region of the first image and the second region of the second image do not match with each other, the displaying of the matching accuracy information and the synthesis image comprises at least one of: distinguishably displaying a predetermined portion corresponding to a mismatched region between the first region of the first image and the second region of the second image; and changing and displaying at least one of a color, shape, and pattern of a marker representing a location of an overlapped region between the first image and the second image. 
     The medical image processing method of claim  10 , further comprises receiving a user input for correcting a range of at least one of the first region of the first image and the second region of the second image; and correcting the range of the at least one of the first region and the second region, based on the user input, and re-generating a synthesis image by using a result of the correction. 
     The generating of the synthesis image comprises: receiving first location information representing a location of a detector for detecting an X-ray transmitted by the object during capturing of the first image, and receives second location information representing a location of the detector during capturing of the second image; and determining the first region of the first image and the second region of the second image based on the first location information and the second location information, and overlapping the first region with the second region to generate the synthesis image. 
     An X-ray imaging apparatus comprises a source configured to radiate an X-ray to an object; a detector configured to detect an X-ray transmitted by the object; a processor configured to control a location of at least one of the source and the detector, acquire an image captured based on the location of the source and the location of the detector, and acquire error information of the captured image due to a location error of at least one of the source and the detector from the captured image; and a display configured to display information about correction of the at least one location error, based on the captured image and the error information of the captured image. 
     The processor generates a predicted image based on the location of the source and the location of the detector, compares the captured image with the predicted image, and acquires the error information of the captured image according to a result of the comparison. 
     The X-ray imaging apparatus further comprises an input unit configured to receive a user input of correcting the at least one location error, wherein the processor corrects the at least one location error by changing a location of at least one of the source and the detector, based on the user input. 
     The processor acquires a first image and a second image of the object captured based on the correction of the at least one location error, and overlaps a first region of the first image with a second region of the second image, wherein the first and second regions correspond to a predetermined region of the object, to generate a synthesis image, and the display displays the synthesis image. 
     The processor detects an error due to a difference between magnification ratios of the captured image and the predicted image and corrects the magnification ratio of the captured image to the magnification ratio of the predicted image based on the user input, and the input unit receives a user input for correcting the error due to the difference between the magnification ratios. 
     The X-ray imaging apparatus further comprises a memory configured to store a driving range and location information of the X-ray imaging apparatus, wherein the processor controls a photographing operation based on the driving range and the location information and acquires a corrected driving range and corrected location information based on the location error of the at least one of the source and the detector, and the memory stores the corrected driving range and the corrected location information. 
     The processor detects a collimator region corresponding to an X-ray irradiated region of a collimator from the captured image, acquires information about an area of the collimator region and a central point of the collimator region from the captured image, and compares the information about the area of the collimator region and the central point of the collimator region with preset information about the area of the collimator region and a central point of the detector to acquire the error information of the captured image. 
     The input unit receives at least one of a user input of adjusting the area of the collimator region and a user input of adjusting the central point of the collimator region, and the processor adjusts at least one of the area of the collimator region and the central point of the collimator region according to the received user input. 
     The processor detects a collimator region corresponding to an X-ray irradiated region of a collimator from the captured image, acquires, from the captured image, first captured coordinate values representing coordinate values of a plurality of vertices of the collimator region, calculates first predicted coordinate values representing predicted coordinate values of the plurality of vertices of the collimator region, based on the location of the source and the location of the detector, and acquires error information of the captured image with respect to the collimator region by comparing the first predicted coordinate values with the first captured coordinate values, and the display displays the error information with respect to the collimator region. 
     The input unit receives a user input of moving the collimator region so that the first captured coordinate values are identical with the first predicted coordinate values, based on the error information, and the processor controls the source to move the collimator region based on the user input. 
     A method of operating an X-ray imaging apparatus, the method comprises controlling a location of at least one of a source that radiates an X ray to an object and a detector that detects an X ray transmitted by the object; acquiring an image captured based on a location of the source and a location of the detector; acquiring error information of the captured image due to a location error of at least one of the source and the detector from the captured image; and displaying information about correction of the at least one location error, based on the captured image and the error information of the captured image. 
     The acquiring of the error information of the captured image comprises: generating a predicted image based on the location of the source and the location of the detector; and comparing the captured image with the predicted image and acquiring the error information of the captured image according to a result of the comparison. 
     The method further comprises receiving a user input of correcting the at least one location error from a user interface (UI) screen image; and correcting the at least one location error by changing the location of the at least one of the source and the detector, based on the user input. 
     The method further comprises acquiring a first image and a second image of the object, based on the correction of the at least one location error; generating a synthesis image by overlapping a first region of the first image with a second region of the second image, wherein the first and second regions correspond to a predetermined region of the object; and displaying the synthesis image. 
     The acquiring of the error information of the captured image due to the location error of the at least one of the source and the detector comprises detecting an error due to a difference between magnification ratios of the captured image and the predicted image, the receiving of the user input of correcting the at least one location error comprises receiving a user input for correcting the error due to the difference between the magnification ratios, and 
     the correcting of the at least one location error by changing the location of the at least one of the source and the detector comprises correcting the magnification ratio of the captured image to the magnification ratio of the predicted image, based on the user input of correcting the error due to the difference between the magnification ratios. 
     The method further comprises storing a driving range and location information of the X-ray imaging apparatus, wherein the acquiring of the image captured based on the location of the source and the location of the detector comprises controlling a photographing operation based on the driving range and the location information, and the method further comprises: acquiring a corrected driving range and corrected location information based on the location error of the at least one of the source and the detector; and storing the corrected driving range and the corrected location information. 
     The acquiring of the error information of the captured image comprises: detecting a collimator region corresponding to an X-ray irradiated region of a collimator from the captured image; acquiring information about an area of the collimator region and a central point of the collimator region from the captured image; and comparing the information about the area of the collimator region and the central point of the collimator region with preset information about the area of the collimator region and a central point of the detector. 
     The receiving of the user input of correcting the at least one location error from the UI screen image comprises: receiving at least one of a user input of adjusting the area of the collimator region and a user input of adjusting the central point of the collimator region; and adjusting at least one of the area of the collimator region and the central point of the collimator region according to the received user input. 
     The acquiring of the error information of the captured image comprises: detecting a collimator region corresponding to an X-ray irradiated region of a collimator from the captured image; acquiring, from the captured image, first captured coordinate values representing coordinate values of a plurality of vertices of the collimator region; calculating first predicted coordinate values representing predicted coordinate values of the plurality of vertices of the collimator region, based on the location of the source and the location of the detector; and acquiring error information of the captured image by comparing the first predicted coordinate values with the first captured coordinate values, and the displaying of the UI screen image comprises displaying error information with respect to the collimator region. 
     The receiving of the user input of correcting the at least one location error from the UI screen image comprises receiving a user input of moving the collimator region so that the first captured coordinate values are identical with the first predicted coordinate values, based on the error information, and the correcting of the at least one location error by changing the location of the at least one of the source and the detector comprises controlling the source to move the collimator region according to a user input of moving the collimator region so that the first captured coordinate values are identical with the first predicted coordinate values. 
     Advantages and features of one or more embodiments of the present invention and methods of accomplishing the same may be understood more readily by reference to the following detailed description of the embodiments and the accompanying drawings. In this regard, the present embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the concept of the present embodiments to one of ordinary skill in the art, and the present invention will only be defined by the appended claims. 
     Hereinafter, the terms used in the specification will be briefly described, and then the present disclosure will be described in detail. 
     The terms used in this specification are those general terms currently widely used in the art in consideration of functions regarding the inventive concept, but the terms may vary according to the intention of those of ordinary skill in the art, precedents, or new technology in the art. Also, some terms may be arbitrarily selected by the applicant, and in this case, the meaning of the selected terms will be described in detail in the detailed description of the present specification. Thus, the terms used herein have to be defined based on the meaning of the terms together with the description throughout the specification. 
     Throughout the specification, an “image” may denote multi-dimensional data composed of discrete image elements (for example, pixels in a two-dimensional image and voxels in a three-dimensional image). For example, an image may be a medical image of an object acquired by an X-ray apparatus, a computed tomography (CT) apparatus, a magnetic resonance imaging (MM) apparatus, an ultrasound diagnosis apparatus, or another medical imaging apparatus. 
     Furthermore, in the present specification, an “object” may be a human, an animal, or a part of a human or animal. For example, the object may include an organ (for example, the liver, the heart, the womb, the brain, breasts, or the abdomen), blood vessels, or a combination thereof. The object may be a phantom. The phantom denotes a material having a volume, a density, and an effective atomic number that are approximately the same as those of a living organism. For example, the phantom may be a spherical phantom having similar properties to those of the human body. 
     Throughout the specification, a “user” may be, but is not limited to, a medical expert, for example, a medical doctor, a nurse, a medical laboratory technologist, or a medical imaging expert, or a technician who repairs medical apparatuses. 
     An X-ray apparatus is a medical imaging apparatus that acquires images of internal structures of an object by transmitting an X-ray through the human body. The X-ray apparatus may acquire medical images of an object more simply within a shorter time than other medical imaging apparatuses including an Mill apparatus and a CT apparatus. Therefore, the X-ray apparatus is widely used in simple chest imaging, simple abdomen imaging, simple skeleton imaging, simple nasal sinuses imaging, simple neck soft tissue imaging, and breast imaging. 
     While such terms as “first,” “second,” etc., may be used to describe various components, such components must not be limited to the above terms. The above terms are used only to distinguish one component from another. For example, a first component discussed below could be termed a second component, and similarly, a second component may be termed a first component without departing from the teachings of this disclosure. The term “and/or” includes any and all combinations of one or more of the associated listed items. 
       FIG. 1  is a block diagram of an X-ray system  1000 . 
     Referring to  FIG. 1 , the X-ray system  1000  includes an X-ray apparatus  100  and a workstation  110 . The X-ray apparatus  100  shown in  FIG. 1  may be a fixed-type X-ray apparatus or a mobile X-ray apparatus. The X-ray apparatus  100  may include an X-ray radiator  120 , a high voltage generator  121 , a detector  130 , a manipulator  140 , and a controller  150 . The controller  150  may control overall operations of the X-ray apparatus  100 . 
     The high voltage generator  121  generates a high voltage for generating X-rays, and applies the high voltage to an X-ray source  122 . 
     The X-ray radiator  120  includes the X-ray source  122  receiving the high voltage from the high voltage generator  121  to generate and radiate X-rays, and a collimator  123  for guiding a path of the X-ray radiated from the X-ray source  122  and adjusting an irradiation region radiated by the X-ray. 
     The X-ray source  122  includes an X-ray tube that may be realized as a vacuum tube diode including a cathode and an anode. An inside of the X-ray tube is set as a high vacuum state of about 10 mmHg, and a filament of the anode is heated to a high temperature to generate thermal electrons. The filament may be a tungsten filament, and a voltage of about 10V and a current of about 3 to 5 A may be applied to an electric wire connected to the filament to heat the filament. 
     In addition, when a high voltage of about 10 to about 300 kVp is applied between the cathode and the anode, the thermal electrons are accelerated to collide with a target material of the cathode, and then, an X-ray is generated. The X-ray is radiated outside via a window, and the window may be formed of a beryllium thin film. In this case, most of the energy of the electrons colliding with the target material is consumed as heat, and remaining energy is converted into the X-ray. 
     The cathode is mainly formed of copper, and the target material is disposed opposite to the anode. The target material may be a high resistive material such as chromium (Cr), iron (Fe), cobalt (Co), nickel (Ni), tungsten (W), or molybdenum (Mo). The target material may be rotated by a rotating field. When the target material is rotated, an electron impact area is increased, and a heat accumulation rate per unit area may be increased to be at least ten times greater than that of a case where the target material is fixed. 
     The voltage applied between the cathode and the anode of the X-ray tube is referred to as a tube voltage, and the tube voltage is applied from the high voltage generator  121  and a magnitude of the tube voltage may be expressed by a crest value (kVp). When the tube voltage increases, a velocity of the thermal electrons increases, and accordingly, an energy of the X-ray (energy of photon) that is generated when the thermal electrons collide with the target material is increased. The current flowing in the X-ray tube is referred to as a tube current that may be expressed as an average value (mA). When the tube current increases, the number of thermal electrons emitted from the filament is increased, and accordingly, the X-ray dose (the number of X-ray photons) generated when the thermal electrons collide with the target material is increased. 
     Therefore, the energy of the X-ray may be adjusted according to the tube voltage, and the intensity of the X-ray or the X-ray dose may be adjusted according to the tube current and the X-ray exposure time. 
     The detector  130  detects an X-ray that is radiated from the X-ray radiator  120  and has been transmitted through an object. The detector  130  may be a digital detector. The detector  130  may be implemented by using a thin film transistor (TFT) or a charge coupled device (CCD). Although the detector  130  is included in the X-ray apparatus  100  in  FIG. 1 , the detector  130  may be an X-ray detector that is a separate device capable of being connected to or separated from the X-ray apparatus  100 . 
     The X-ray apparatus  100  may further include a manipulator  140  for providing a user with an interface for manipulating the X-ray apparatus  100 . The manipulator  140  may include an output unit  141  and an input unit  142 . The input unit  142  may receive from a user a command for manipulating the X-ray apparatus  100  and various types of information related to X-ray imaging. The controller  150  may control or manipulate the X-ray apparatus  100  according to the information received by the input unit  142 . The output unit  141  may output sound representing information related to an imaging operation such as the X-ray radiation under the control of the controller  150 . 
     The workstation  110  and the X-ray apparatus  100  may be connected to each other by wire or wirelessly. When they are connected to each other wirelessly, a device (not shown) for synchronizing clock signals with each other may be further included. The workstation  110  and the X-ray apparatus  100  may exist within physically separate spaces. 
     The workstation  110  may include an output unit  111 , an input unit  112 , and a controller  113 . The output unit  111  and the input unit  112  provide a user with an interface for manipulating the workstation  110  and the X-ray apparatus  200 . The controller  113  may control the workstation  110  and the X-ray apparatus  200 . 
     The X-ray apparatus  100  may be controlled via the workstation  110  or may be controlled by the controller  150  included in the X-ray apparatus  100 . Accordingly, a user may control the X-ray apparatus  100  via the workstation  110  or may control the X-ray apparatus  100  via the manipulator  140  and the controller  150  included in the X-ray apparatus  100 . In other words, a user may remotely control the X-ray apparatus  100  via the workstation  110  or may directly control the X-ray apparatus  100 . 
     Although the controller  113  of the workstation  110  is separate from the controller  150  of the X-ray apparatus  100  in  FIG. 1 ,  FIG. 1  is only an example. As another example, the controllers  113  and  150  may be integrated into a single controller, and the single controller may be included in only one of the workstation  110  and the X-ray apparatus  100 . Hereinafter, the controllers  113  and  150  may denote the controller  113  of the workstation  110  and/or the controller  150  of the X-ray apparatus  100 . 
     The output unit  111  and the input unit  112  of the workstation  110  may provide a user with an interface for manipulating the X-ray apparatus  100 , and the output unit  141  and the input unit  142  of the X-ray apparatus  100  may also provide a user with an interface for manipulating the X-ray apparatus  100 . Although the workstation  110  and the X-ray radiation apparatus  100  include the output units  111  and  141 , respectively, and the input units  112  and  142 , respectively, in  FIG. 1 , embodiments are not limited thereto. Only one of the workstation  110  and the X-ray apparatus  100  may include an output unit or an input unit. 
     Hereinafter, the input units  112  and  142  may denote the input unit  112  of the workstation  110  and/or the input unit  142  of the X-ray apparatus  100 , and the output units  111  and  141  may denote the output unit  111  of the workstation  110  and/or the output unit  141  of the X-ray apparatus  100 . 
     Examples of the input units  112  and  142  may include a keyboard, a mouse, a touch screen, a voice recognizer, a fingerprint recognizer, an iris recognizer, and other input devices which are well known to one of ordinary skill in the art. The user may input a command for radiating the X-ray via the input units  112  and  142 , and the input units  112  and  142  may include a switch for inputting the command. The switch may be configured so that a radiation command for radiating the X-ray may be input only when the switch is pushed in two steps. 
     In other words, when the user pushes the switch, a prepare command for performing a pre-heating operation for X-ray radiation may be input, and in this state, when the user pushes the switch deeper, a radiation command for performing substantial X-ray radiation may be input. When the user manipulates the switch as described above, the controllers  113  and  150  generate signals corresponding to the commands input through the switch manipulation, that is, a prepare signal, and transmit the generated signals to the high voltage generator  121  generating a high voltage for generating the X-ray. 
     When the high voltage generator  121  receives the prepare signal from the controllers  113  and  150 , the high voltage generator  121  starts a pre-heating operation, and when the pre-heating is finished, the high voltage generator  121  outputs a ready signal to the controllers  113  and  150 . In addition, the detector  130  also needs to prepare to detect the X-ray, and thus the high voltage generator  121  performs the pre-heating operation and the controllers  113  and  150  transmit a prepare signal to the detector  130  so that the detector  130  may prepare to detect the X-ray transmitted through the object. The detector  130  prepares to detect the X-ray in response to the prepare signal, and when the preparing for the detection is finished, the detector  130  outputs a ready signal to the controllers  113  and  150 . 
     When the pre-heating operation of the high voltage generator  121  is finished and the detector  130  is ready to detect the X-ray, the controllers  113  and  150  transmit a radiation signal to the high voltage generator  121 , the high voltage generator  121  generates and applies the high voltage to the X-ray source  122 , and the X-ray source  122  radiates the X-ray. 
     When the controllers  113  and  150  transmit the radiation signal to the high voltage generator  121 , the controllers  113  and  150  may transmit a sound output signal to the output units  111  and  141  so that the output units  111  and  141  output a predetermined sound and the object may recognize the radiation of the X-ray. The output units  111  and  141  may also output a sound representing information related to photographing in addition to the X-ray radiation. In  FIG. 1 , the output unit  141  is included in the manipulator  140 ; however, the embodiments are not limited thereto, and the output unit  141  or a portion of the output unit  141  may be located elsewhere. For example, the output unit  141  may be located on a wall of an examination room in which the X-ray photographing of the object is performed. 
     The controllers  113  and  150  control locations of the X-ray radiator  120  and the detector  130 , photographing timing, and photographing conditions, according to photographing conditions set by the user. 
     In more detail, the controllers  113  and  150  control the high voltage generator  121  and the detector  130  according to the command input via the input units  112  and  142  so as to control radiation timing of the X-ray, an intensity of the X-ray, and a region radiated by the X-ray. In addition, the control units  113  and  150  adjust the location of the detector  130  according to a predetermined photographing condition, and controls operation timing of the detector  130 . 
     Furthermore, the controllers  113  and  150  generate a medical image of the object by using image data received via the detector  130 . In detail, the controllers  113  and  150  may receive the image data from the detector  130 , and then, generate the medical image of the object by removing noise from the image data and adjusting a dynamic range and interleaving of the image data. 
     The output units  111  and  141  may output the medical image generated by the controllers  113  and  150 . The output units  111  and  141  may output information that is necessary for the user to manipulate the X-ray apparatus  100 , for example, a user interface (UI), user information, or object information. Examples of the output units  111  and  141  may include a speaker, a printer, a cathode ray tube (CRT) display, a liquid crystal display (LCD), a plasma display panel (PDP), an organic light emitting diode (OLED) display, a field emission display (FED), a light emitting diode (LED) display, a vacuum fluorescent display (VFD), a digital light processing (DLP) display, a flat panel display (FPD), a three-dimensional 3D) display, a transparent display, and other various output devices well known to one of ordinary skill in the art. 
     The maximum depth shown in  FIG. 1  may further include a communicator (not shown) that may be connected to a server  162 , a medical apparatus  164 , and a portable terminal  166  via a network  15 . 
     The communicator may be connected to the network  15  by wire or wirelessly to communicate with the server  162 , the medical apparatus  164 , or the portable terminal  166 . The communicator may transmit or receive data related to diagnosis of the object via the network  15 , and may also transmit or receive medical images captured by the medical apparatus  164 , for example, a CT apparatus, an MRI apparatus, or an X-ray apparatus. Moreover, the communicator may receive a medical history or treatment schedule of an object (e.g., a patient) from the server  162  to diagnose a disease of the object. Also, the communicator may perform data communication with the portable terminal  166  such as a mobile phone, a personal digital assistant (PDA), or a laptop computer of a medical doctor or a client, as well as the server  162  or the medical apparatus  164  in a hospital. 
     The communicator may include one or more elements enabling communication with external apparatuses. For example, the communicator may include a local area communication module, a wired communication module, and a wireless communication module. 
     The local area communication module refers to a module for performing local area communication with an apparatus located within a predetermined distance. Examples of local area communication technology may include, but are not limited to, a wireless local area network (LAN), Wi-Fi, Bluetooth, ZigBee, Wi-Fi Direct (WFD), ultra wideband (UWD), infrared data association (IrDA), Bluetooth low energy (BLE), and near field communication (NFC). 
     The wired communication module refers to a module for communicating by using an electric signal or an optical signal. Examples of wired communication technology may include wired communication techniques using a pair cable, a coaxial cable, and an optical fiber cable, and other wired communication techniques that are well known to one of ordinary skill in the art. 
     The wireless communication module transmits and receives a wireless signal to and from at least one selected from a base station, an external apparatus, and a server in a mobile communication network. Here, examples of the wireless signal may include a voice call signal, a video call signal, and various types of data according to text/multimedia messages transmission. 
     The X-ray apparatus  100  shown in  FIG. 1  may include a plurality of digital signal processors (DSPs), an ultra-small calculator, and a processing circuit for special purposes (for example, high speed analog/digital (A/D) conversion, high speed Fourier transformation, and an array process). 
     In addition, communication between the workstation  110  and the X-ray apparatus  100  may be performed using a high speed digital interface, such as low voltage differential signalling (LVDS), asynchronous serial communication, such as a universal asynchronous receiver transmitter (UART), a low latency network protocol, such as error synchronous serial communication or a controller area network (CAN), or any of other various communication methods that are well known to one of ordinary skill in the art. 
       FIG. 2  is a perspective view of a fixed type X-ray apparatus  200 . The fixed type X-ray apparatus  200  may be another embodiment of the X-ray apparatus  100  of  FIG. 1 . Components included in the fixed type X-ray apparatus  200  that are the same as those of the X-ray apparatus  100  of  FIG. 1  use the same reference numerals, and repeated descriptions thereof will be omitted. 
     Referring to  FIG. 2 , the fixed type X-ray apparatus  200  includes a manipulator  140  providing a user with an interface for manipulating the X-ray apparatus  200 , an X-ray radiator  120  radiating an X-ray to an object, a detector  130  detecting an X-ray that has passed through the object, first, second, and third motors  211 ,  212 , and  213  providing a driving power to transport the X-ray radiator  120 , a guide rail  220 , a moving carriage  230 , and a post frame  240 . The guide rail  220 , the moving carriage  230 , and the post frame  240  are formed to transport the X-ray radiator  120  by using the driving power of the first, second, and third motors  211 ,  212 , and  213 . 
     The guide rail  220  includes a first guide rail  221  and a second guide rail  222  that are provided to form a predetermined angle with respect to each other. The first guide rail  221  and the second guide rail  222  may respectively extend in directions crossing each other at 90°. 
     The first guide rail  221  is provided on the ceiling of an examination room in which the X-ray apparatus  200  is disposed. 
     The second guide rail  222  is located under the first guide rail  221 , and is mounted so as to slide along the first guide rail  221 . A roller (not shown) that may move along the first guide rail  221  may be provided on the first guide rail  221 . The second guide rail  222  is connected to the roller to move along the first guide rail  221 . 
     A first direction D 1  is defined as a direction in which the first guide rail  221  extends, and a second direction D 2  is defined as a direction in which the second guide rail  222  extends. Therefore, the first direction D 1  and the second direction D 2  cross each other at 90°, and may be parallel to the ceiling of the examination room. 
     The moving carriage  230  is disposed under the second guide rail  222  so as to move along the second guide rail  222 . A roller (not shown) moving along the second guide rail  222  may be provided on the moving carriage  230 . 
     Therefore, the moving carriage  230  may move in the first direction D 1  together with the second guide rail  222 , and may move in the second direction D 2  along the second guide rail  222 . 
     The post frame  240  is fixed on the moving carriage  230  and located under the moving carriage  230 . The post frame  240  may include a plurality of posts  241 ,  242 ,  243 ,  244 , and  245 . 
     The plurality of posts  241 ,  242 ,  243 ,  244 , and  245  are connected to each other to be foldable, and thus, the post frame  240  may have a length that is adjustable in a vertical direction of the examination room while in a state of being fixed to the moving carriage  230 . 
     A third direction D 3  is defined as a direction in which the length of the post frame  240  increases or decreases. Therefore, the third direction D 3  may be perpendicular to the first direction D 1  and the second direction D 2 . 
     The detector  130  detects the X-ray that has passed through the object, and may be combined with a table type receptor  290  or a stand type receptor  280 . 
     A rotating joint  250  is disposed between the X-ray radiator  120  and the post frame  240 . The rotating joint  250  allows the X-ray radiator  120  to be coupled to the post frame  240 , and supports a load applied to the X-ray radiator  120 . 
     The X-ray radiator  120  connected to the rotating joint  250  may rotate on a plane that is perpendicular to the third direction D 3 . In this case, a rotating direction of the X-ray radiator  120  may be defined as a fourth direction D 4 . 
     Also, the X-ray radiator  120  may be configured to be rotatable on a plane perpendicular to the ceiling of the examination room. Therefore, the X-ray radiator  120  may rotate in a fifth direction D 5  that is a rotating direction about an axis that is parallel with the first direction D 1  or the second direction D 2 , with respect to the rotating joint  250 . 
     The first, second, and third motors  211 ,  212 , and  213  may be provided to move the X-ray radiator  120  in the first, second, and third directions D 1 , D 2 , and D 3 . The first, second, and third motors  211 ,  212 , and  213  may be electrically driven, and the first, second, and third motors  211 ,  212 , and  213  may respectively include an encoder. 
     The first, second, and third motors  211 ,  212 , and  213  may be disposed at various locations in consideration of design convenience. For example, the first motor  211 , moving the second guide rail  222  in the first direction D 1 , may be disposed around the first guide rail  221 , the second motor  212 , moving the moving carriage  230  in the second direction D 2 , may be disposed around the second guide rail  222 , and the third motor  213 , increasing or reducing the length of the post frame  240  in the third direction D 3 , may be disposed in the moving carriage  230 . In another example, the first, second, and third motors  211 ,  212 , and  213  may be connected to a driving power transfer unit (not shown) so as to linearly move the X-ray radiator  120  in the first, second, and third directions D 1 , D 2 , and D 3 . The driving power transfer unit may be a combination of a belt and a pulley, a combination of a chain and a sprocket, or a shaft, which are generally used. 
     In another example, motors (not shown) may be disposed between the rotating joint  250  and the post frame  240  and between the rotating joint  250  and the X-ray radiator  120  in order to rotate the X-ray radiator  120  in the fourth and fifth directions D 4  and D 5 . 
     The manipulator  140  may be disposed on a side surface of the X-ray radiator  120 . 
       FIG. 2  shows the fixed type X-ray apparatus  200  connected to the ceiling of the examination room, the fixed type X-ray apparatus  200  is merely an example for convenience of comprehension. That is, X-ray apparatuses according to embodiments of the present disclosure may include X-ray apparatuses having various structures that are well known to one of ordinary skill in the art, for example, a C-arm-type X-ray apparatus and an angiography X-ray apparatus, in addition to the fixed type X-ray apparatus  200  of  FIG. 2 . 
       FIG. 3  is a diagram showing a configuration of a mobile X-ray apparatus  300  capable of performing an X-ray photographing operation regardless of a place where the photographing operation is performed. The mobile X-ray apparatus  300  may be another embodiment of the X-ray apparatus  100  of  FIG. 1 . Components included in the mobile X-ray apparatus  300  that are the same as those of the X-ray apparatus  100  of  FIG. 1  use the same reference numerals as those used in  FIG. 1 , and a repeated description thereof will be omitted. 
     Referring to  FIG. 3 , the mobile X-ray apparatus  300  includes a transport unit  370  including a wheel for transporting the mobile X-ray apparatus  300 , a main unit  305 , an X-ray radiator  120 , and a detector  130  detecting an X-ray that is radiated from the X-ray radiator  120  toward an object and transmitted through the object. The main unit  305  includes a manipulator  140  providing a user with an interface for manipulating the mobile X-ray apparatus  300 , a high voltage generator  121  generating a high voltage applied to an X-ray source  122 , and a controller  150  controlling overall operations of the mobile X-ray apparatus  300 . The X-ray radiator  120  includes the X-ray source  122  generating the X-ray, and a collimator  123  guiding a path along which the generated X-ray is emitted from the X-ray source  122  and adjusting an irradiation region radiated by the X-ray. 
     The detector  130  in  FIG. 3  may not be combined with any receptor, and the detector  130  may be a portable detector which can exist anywhere. 
     In  FIG. 3 , the manipulator  140  is included in the main unit  305 ; however, embodiments are not limited thereto. For example, as illustrated in  FIG. 2 , the manipulator  140  of the mobile X-ray apparatus  300  may be disposed on a side surface of the X-ray radiator  120 . 
       FIG. 4  is a block diagram illustrating a structure of the CT system  400 . The detector  400  may be an embodiment of the detector  130  of  FIGS. 1-3 . The detector  400  may be an indirect type detector. 
     Referring to  FIG. 4 , the detector  400  may include a scintillator (not shown), a photodetecting substrate  410 , a bias driver  430 , a gate driver  450 , and a signal processor  470 . 
     The scintillator receives the X-ray radiated from the X-ray source  122  and converts the X-ray into light. 
     The photodetecting substrate  410  receives the light from the scitillator and converts the light into an electrical signal. The photodetecting substrate  410  may include gate lines GL, data lines DL, TFTs  412 , photodiodes  414 , and bias lines BL. 
     The gate lines GL may be formed in the first direction DR 1 , and the data lines DL may be formed in the second direction DR 2  that crosses the first direction DR 1 . The first direction DR 1  and the second direction DR 2  may intersect perpendicularly to each other.  FIG. 4  shows four gate lines GL and four data lines DL as an example. 
     The TFTs  412  may be arranged as a matrix in the first and second directions DR 1  and DR 2 . Each of the TFTs  412  may be electrically connected to one of the gate lines GL and one of the data lines DL. A gate of the TFT  412  may be electrically connected to the gate line GL, and a source of the TFT  412  may be electrically connected to the data line DL. In  FIG. 4 , sixteen TFTs  412  (in a 4×4 arrangement) are shown as an example. 
     The photodiodes  414  may be arranged as a matrix in the first and second directions DR 1  and DR 2  so as to respectively correspond to the TFTs  412 . Each of the photodiodes  414  may be electrically connected to one of the TFTs  412 . An N-side electrode of each of the photodiodes  414  may be electrically connected to a drain of the TFT  412 .  FIG. 4  shows sixteen photodiodes  414  (in a 4×4 arrangement) as an example. 
     The bias lines BL are electrically connected to the photodiodes  414 . Each of the bias lines BL may be electrically connected to P-side electrodes of an array of photodiodes  414 . For example, the bias lines BL may be formed to be substantially parallel with the second direction DR 2  so as to be electrically connected to the photodiodes  414 . On the other hand, the bias lines BL may be formed to be substantially parallel with the first direction DR 1  so as to be electrically connected to the photodiodes  414 .  FIG. 4  shows four bias lines BL formed along the second direction DR 2  as an example. 
     The bias driver  430  is electrically connected to the bias lines BL so as to apply a driving voltage to the bias lines BL. The bias driver  430  may selectively apply a reverse bias voltage or a forward bias voltage to the photodiodes  414 . A reference voltage may be applied to the N-side electrodes of the photodiodes  414 . The reference voltage may be applied via the signal processor  470 . The bias driver  430  may apply a voltage that is less than the reference voltage to the P-side electrodes of the photodiodes  414  so as to apply a reverse bias voltage to the photodiodes  414 . On the other hand, the bias driver  430  may apply a voltage that is greater than the reference voltage to the P-side electrodes of the photodiodes  414  so as to apply a forward bias voltage to the photodiodes  414 . 
     The gate driver  450  is electrically connected to the gate lines GL and thus may apply gate signals to the gate lines GL. For example, when the gate signals are applied to the gate lines GL, the TFTs  412  may be turned on by the gate signals. On the other hand, when the gate signals are not applied to the gate lines GL, the TFTs  412  may be turned off. 
     The signal processor  470  is electrically connected to the data lines DL. When the light received by the photodetecting substrate  410  is converted into the electrical signal, the electrical signal may be read out by the signal processor  470  via the data lines DL. 
     An operation of the detector  400  will now be described. During the operation of the detector  400 , the bias driver  430  may apply the reverse bias voltage to the photodiodes  414 . 
     While the TFTs  412  are turned off, each of the photodiodes  414  may receive the light from the scintillator and generate electron-hole pairs to accumulate electric charges. The amount of electric charge accumulated in each of the photodiodes  414  may correspond to the intensity of the received X-ray. 
     Then, the gate driver  450  may sequentially apply the gate signals to the gate lines GL along the second direction DR 2 . When a gate signal is applied to a gate line GL and thus TFTs  412  connected to the gate line GL are turned on, photocurrents may flow into the signal processor  470  via the data lines DL due to the electric charges accumulated in the photodiodes  414  connected to the turned-on TFTs  412 . 
     The signal processor  470  may convert the received photocurrents into image data. The signal processor  470  may output the image data to the outside. The image data may be in the form of an analog signal or a digital signal corresponding to the photocurrents. 
     Although not shown in  FIG. 4 , if the detector  400  shown in  FIG. 4  is a wireless detector, the detector  400  may further include a battery unit and a wireless communication interface unit. 
       FIG. 5  explains a result of synthesizing a plurality of images having an overlapped region, according to an embodiment. 
     When an X-ray penetrates through an object, the X-ray is attenuated according to the property and distance of the object. Due to the attenuating characteristics of X-rays, X-ray imaging apparatuses capable of examining an internal shape of a human body or an object are widely used for non-destructive examination for a medical use or an industrial use. 
     A captured region of an object that may be captured at a time by an X-ray imaging apparatus may be limited to a certain region on the object depending on the capturing accuracy or object resolution of the apparatus. Thus, the X-ray imaging apparatus may acquire an image having a wider area or a higher resolution by combining a plurality of captured images according to an image stitching technique. 
     For example, the X-ray imaging apparatus may acquire a plurality of images by photographing the lower part of a human body, and combine the plurality of images together to generate a synthesis image. In this case, the synthesis image may include a mismatched region due to the combination of the plurality of images. 
     An image  510  of  FIG. 5  is a synthesis image having a mismatched region  501  due to a location error of the X-ray imaging apparatus. An image  520  of  FIG. 5  is a synthesis image having a mismatched region  502  due to a magnification ratio error for at least one of the plurality of images. 
     Thus, the X-ray imaging apparatus needs to generate a seamless image in which images accurately overlap each other, as shown in an image  530  of  FIG. 5 . 
       FIG. 6A  is a block diagram of a structure of a medical image processing apparatus  600  according to an embodiment. 
     According to an embodiment, the medical image processing apparatus  600  may include a processor  610  and a display  620 . It will be understood by one of ordinary skill in the art to which this embodiment pertains that the medical image processing apparatus  600  may include other general-use components in addition to the components illustrated in  FIG. 6A . 
     The medical image processing apparatus  600  of  FIG. 6A  may be the X-ray apparatus  100  of  FIG. 1 , the workstation  110  of  FIG. 1 , the medical apparatus  164  of  FIG. 1 , the portable terminal  166  of  FIG. 1 , a medical imaging apparatus, a medical server, or any computing device capable of using and processing a medical image. In detail, the processor  610  of the medical image processing apparatus  600  of  FIG. 6A  may correspond to the controller  150  of the X-ray apparatus  100  of  FIG. 1  or the controller  113  of the workstation  110  of  FIG. 1 . The display  620  of the medical image processing apparatus  600  of  FIG. 6A  may correspond to the output unit  141  of the X-ray apparatus  100  of  FIG. 1  or the output unit  111  of the workstation  110  of  FIG. 1 . A description of  FIG. 6A  that is the same as given above with reference to  FIG. 1  will not be repeated herein. The structure of the medical image processing apparatus  600  of  FIG. 6A  will now be described. 
     The processor  610  may acquire a first image and a second image captured by radiating an X ray to an object. The first image and the second image are captured by consecutively photographing a predetermined part of the object. The processor  610  may generate a synthesis image by overlapping a first region of the first image with a second region of the second image. In detail, the processor  610  may generate a synthesis image by overlapping a first region of the first image corresponding to a predetermined region of the object with a second region of the second image corresponding to the predetermined region of the object. The terms “first image” and “second image” described with reference to  FIGS. 6A-10B  may denote captured images commonly including a predetermined region of an object. 
     The processor  610  may generate a synthesis image by combining a plurality of images by using location information of a detector located when capturing each of the plurality of images. The detector is an apparatus for detecting an X-ray transmitted by the object. In detail, the processor  610  may receive first location information representing a location of the detector during capturing of the first image, and receive second location information representing a location of the detector during capturing of the second image. For example, the first location information may be first height coordinate information of the detector, and the second location information may be second height coordinate information of the detector. The processor  610  may determine overlapping regions of the first image and the second image, based on the first location information and the second location information. The processor  610  may determine the first region of the first image and the second region of the second image as the overlapping regions and overlap the overlapping regions to generate a synthesis image. This will be described in detail with reference to  FIG. 8 . 
     The processor  610  may acquire information of matching accuracy representing the degree to which the overlapping regions corresponding to the first region of the first image and the second region of the second image match with each other. The information of the matching accuracy may include, but is not limited to, at least one of information about a length of an overlap between the first image and the second image on the synthesis image, information about a location of an overlapped region on the synthesis image, and information about the matching accuracy representing a match rate between the first region of the first image and the second region of the second image. The matching accuracy representing the match rate between the first region of the first image and the second region of the second image may be expressed in percentage. 
     The display  620  may output an acquired image. The display  620  may display not only an image but also various pieces of information that are processed by the medical image processing apparatus  600 , on a screen via a graphical user interface (GUI). The medical image processing apparatus  600  may include two or more displays  620  according to embodiments. 
     The first image and the second image may be acquired by the medical image processing apparatus  600  directly photographing the object, or may be acquired by an external apparatus physically independent from the medical image processing apparatus  600 . 
     The external apparatus acquires, stores, processes, or utilizes an image and data related with the image. Thus, the external apparatus may be a medical imaging apparatus, a medical server, a portable terminal, or any computing device capable of utilizing and processing medical images. For example, the external apparatus may be a medical diagnosis apparatus included in a medical institution such as a hospital. The external apparatus may be, for example, a server included in a hospital for recoding and storing medical treatment histories of patients, or a medical imaging apparatus used by medical doctors in a hospital to read medical images. 
     The display  620  may display, on the synthesis image, a marker indicating a location of an overlapped region between the first image and the second image. Alternatively, the display  620  may display the marker indicating the location of the overlapped region between the first image and the second image, together with the synthesis image. The display  620  may also display at least one of information about a length of the overlapped region between the first image and the second image on the synthesis image and information about a location of the overlapped region on the synthesis image. 
     The display  620  may display information representing whether matching between the first image and the second image succeeds, based on the matching accuracy. In detail, when the first region of the first image matches with the second region of the second image, the display  620  may display information representing that the matching has succeeded. The information representing that the matching has succeeded may include, but is not limited to, a text representing a match rate of 100%. On the other hand, when the first region of the first image mismatches with the second region of the second image, the display  620  may display information representing that the matching has failed. The information representing that the matching has failed may include a text representing a match rate or a mismatch rate. 
     The processor  610  may distinguishably set at least one of a color, shape, and pattern of the marker representing the location of the overlapped region between the first image and the second image, based on the matching accuracy. The display  620  may distinguish the case where the first region of the first image matches with the second region of the second image from the case where the first region of the first image mismatches with the second region of the second image, and may display matching accuracy information. In detail, when the first region of the first image mismatches with the second region of the second image, the display  620  may distinguishably display a predetermined portion corresponding to a mismatch portion between the first region of the first image and the second region of the second image. For example, the predetermined portion corresponding to the mismatch portion may be displayed in a different color from an existing color of the synthesis image. Alternatively, when the first region of the first image mismatches with the second region of the second image, the display  620  may change and display a color or shape of the marker indicating the location of the overlapped region between the first and second images. 
     The medical image processing apparatus  600  may capture a plurality of images and combine respective overlapping regions of the plurality of images with each another to generate a synthesis image. In this case, the medical image processing apparatus  600  may provide matching accuracy information of the overlapping regions of the plurality of images and thus may provide more accurate information to a patient. 
     The medical image processing apparatus  600  may further include a central processor to control overall operations of the processor  610  and the display  620 . The central processor may be implemented by an array of a plurality of logic gates, or by a combination of a general-use microprocessor and a memory in which a program to be executed by the general-use microprocessor is stored. It will also be understood by one of ordinary skill in the art to which this embodiment pertains that the central processor may be implemented by other types of hardware. 
       FIG. 6B  is a block diagram of a structure of a medical image processing apparatus  650  according to another embodiment. 
     The medical image processing apparatus  650  may include a processor  660 , a display  670 , and an input unit  680 . It will be understood by one of ordinary skill in the art to which this embodiment pertains that the medical image processing apparatus  650  may include other general-use components in addition to the components illustrated in  FIG. 6B . 
     The medical image processing apparatus  650  of  FIG. 6B  may further include the input unit  680 , compared with the medical image processing apparatus  600  of  FIG. 6A . The processor  660  and the display  670  of the medical image processing apparatus  650  of  FIG. 6B  respectively correspond to the processor  610  and the display  620  of the medical image processing apparatus  600  of  FIG. 6A . 
     The input unit  680  of the medical image processing apparatus  650  of  FIG. 6B  may correspond to the input unit  142  of the X-ray apparatus  100  of  FIG. 1  or the input unit  112  of the workstation  110  of  FIG. 1 . A description of  FIG. 6B  that is the same as given above with reference to  FIGS. 1 and 6A  will not be repeated herein. The structure of the medical image processing apparatus  650  of  FIG. 6B  will now be described. 
     The input unit  680  refers to a device via which a user inputs data for controlling the medical image processing apparatus  650 . The input unit  680  may include, but is not limited to, hardware structures such as a keypad, a mouse, a touch panel, a touch screen, a track ball, and a jog switch. The input unit  680  may further include various input units, such as a voice recognition sensor, a gesture recognition sensor, a fingerprint recognition sensor, an iris recognition sensor, a depth sensor, and a distance sensor. 
     The input unit  680  may receive a user input for correcting the range of at least one of the first region of the first image and the second region of the second image. The processor  660  may correct at least one image, based on the user input. 
     The input unit  680  may generate a UI screen image for receiving a command or data from a user, and the display  670  may display the UI screen image. For example, the input unit  680  may receive at least one of an input of correcting a section of an overlapped region between the first image and the second image and an input of adjusting a magnification ratio of the first image or the second image. The UI screen image may include a magnified image of the overlapped region between the first image and the second image and an icon for manipulating the first image or the second image. 
     In more detail, the input unit  680  may receive a manipulation signal generated due to a user touch input via various input tools. The input unit  680  may receive an input of correcting the section of the overlapped region between the first image and the second image displayed on the screen, via a hand or a physical tool of a user, and the processor  660  may correct the section of the overlapped region according to the user input. 
     The medical image processing apparatus  650  may further include a memory (not shown) and a communicator (not shown). The memory (not shown) may store, for example, an image and data related with the image (for example, an X-ray image and diagnosis data of a patient regarding the X-ray image) and data transmitted from an external apparatus to the medical image processing apparatus  650 . The data transmitted by the external apparatus to the medical image processing apparatus  650  may include patient-related information, data necessary for diagnosing and treating patients, histories of previous treatments of patients, and a medical worklist (MWL) corresponding to diagnosis instructions for patients, and the like. The memory (not shown) may store information of the matching accuracy representing the degree to which the overlapping regions of the first image and the second image match with each other. The memory may also store a synthesis image on which the information of the matching accuracy is displayed. The memory may store a synthesis image in which the overlapping regions of the first image and the second image have been corrected based on a user input. 
     The communicator may receive data from the external apparatus and/or transmit data to the external apparatus. For example, the communicator may be connected to the X-ray apparatus  100 , the workstation  110 , the server  162 , the medical apparatus  164 , and the portable terminal  166  via a Wi-Fi or Wi-Fi Direct (WFD) communication network. 
     The medical image processing apparatus  650  provides the matching accuracy information of the overlapping regions of the plurality of images and provides a UI screen image via which a user is able to correct predetermined mismatched portions on the overlapping regions. The medical image processing apparatus  650  may provide a more accurate image to the user by correcting the synthesis image according to a user input of correcting the mismatched portions. 
     The medical image processing apparatus  650  may further include a central processor to control overall operations of the processor  660 , the display  670 , and the input unit  680 . The central processor may be implemented by an array of a plurality of logic gates, or by a combination of a general-use microprocessor and a memory in which a program to be executed by the general-use microprocessor is stored. It will also be understood by one of ordinary skill in the art to which this embodiment pertains that the central processor may be implemented by other types of hardware. 
     Various operations or applications that the medical image processing apparatuses  600  and  650  execute will now be described. However, matters to be clearly understood and expected by one of ordinary skill in the art to which the present invention pertains may be understood by typical implementations even when none of the processors  610  and  660 , the displays  620  and  670 , and the input unit  680  is specified, and the scope of the present invention is not limited by the titles or physical/logical structures of specified components. 
       FIG. 7A  is a flowchart of a medical image processing method according to an embodiment. 
     An operation of the medical image processing apparatus  600  will now be described, but this description is not be limited to the medical image processing apparatus  600  but may be equally applied to the medical image processing apparatus  650 . 
     In operation S 710  of  FIG. 7A , the medical image processing apparatus  600  may acquire a first image and a second image. The first image and the second image are captured by radiating an X ray to an object, and are images captured by consecutively photographing a predetermined part of the object. 
     In operation S 720 , the medical image processing apparatus  600  may generate a synthesis image by overlapping a first region of the first image with a second region of the second image. 
     The medical image processing apparatus  600  may receive first location information representing a location of a detector for detecting an X-ray transmitted by the object during capturing of the first image, and receive second location information representing a location of the detector during capturing of the second image. The medical image processing apparatus  600  may determine the first region of the first image and the second region of the second image based on the first location information and the second location information, and overlap the first region with the second region to generate the synthesis image. 
     In operation S 730 , the medical image processing apparatus  600  may determine matching accuracy representing the degree to which the overlapping regions of the first image and the second image match with each other. The medical image processing apparatus  600  may determine at least one of information about a length of an overlap between the first image and the second image on the synthesis image, information about a location of an overlapped region on the synthesis image, and the matching accuracy representing a match rate between the first region of the first image and the second region of the second image, but the inventive concept is not limited thereto. 
     In operation S 740 , the medical image processing apparatus  600  may display the matching accuracy and the synthesis image. The medical image processing apparatus  600  may display a marker indicating a location of an overlapped region between the first image and the second image, together with the synthesis image. 
     The medical image processing apparatus  600  may display at least one of the information about the length of the overlap between the first image and the second image on the synthesis image and the information about the location of the overlapped region on the synthesis image. 
     The medical image processing apparatus  600  may display information representing whether matching between the first image and the second image has succeeded, based on the matching accuracy. 
     When the first region of the first image mismatches with the second region of the second image, the medical image processing apparatus  600  may change and display a color or shape of the marker indicating the location of the overlapped region between the first and second images. The medical image processing apparatus  600  may distinguishably set and display at least one of a color, shape, and pattern of the marker representing the location of the overlapped region between the first image and the second image, based on the matching accuracy. 
       FIG. 7B  is a flowchart of a medical image processing method according to another embodiment. 
     In operation S 750  of  FIG. 7B , the medical image processing apparatus  650  may receive a user input for correcting the range of at least one of the first region of the first image and the second region of the second image. The medical image processing apparatus  650  may receive an input of correcting a section of the overlapped region between the first image and the second image. The medical image processing apparatus  650  may receive an input of adjusting a magnification ratio of the first image or the second image. 
     In operation S 760 , the medical image processing apparatus  650  may correct at least one image based on the user input, and re-generate a synthesis image by using a result of the correction. The medical image processing apparatus  650  may display the re-generated synthesis image. 
     There may be provided a computer-readable recording medium having recorded thereon a program for the method of executing operations S 710 -S 740  described above with reference to  FIG. 7A . There may also be provided a computer-readable recording medium having recorded thereon a program for the method of executing operations S 710 -S 760  described above with reference to  FIG. 7B . 
       FIG. 8  explains a method of synthesizing a plurality of images captured according to locations on an object, according to an embodiment. 
     Referring to  FIG. 8 , the medical image processing apparatus  650  may acquire the plurality of images by photographing the object by using an X-ray. The medical image processing apparatus  650  may repeatedly photograph a predetermined region on the object in order to acquire consecutive images of the object. The medical image processing apparatus  650  may acquire an image into which the plurality of images are combined. The medical image processing apparatus  650  may include a source that radiates an X-ray to the object, a detector that detects an X-ray transmitted by the object, a processor that controls operations of the source and the detector and overall operations of the medical image processing apparatus  650 , and a display that displays an image. 
     As shown in a image  810  of  FIG. 8 , the source may radiate an X-ray to a head part, a torso part, and a leg part of a human, and the detector may detect X-rays respectively transmitted by the head part, the torso part, and the leg part of the human. The processor may acquire a first image, a second image, and a third image, based on the detected X-rays. 
     The processor may receive, from the detector, first location information representing a location of the detector during photography of the head part, second location information representing a location of the detector during photography of the torso part, and third location information representing a location of the detector during photography of the leg part. Location information of the detector may be, but is not limited to, height information or coordinate information of a location of the detector. For example, the processor may acquire the first location information of the detector as first height coordinate information  801  and  802  of the detector, the second location information of the detector as second height coordinate information  803  and  804  of the detector, and the third location information of the detector as third height coordinate information  805  and  806  of the detector. 
     The processor may detect an overlapped region between the first image and the second image by using the first height coordinate information  801  and  802  and the second height coordinate information  803  and  804 . The processor may also detect an overlapped region between the second image and the third image by using the second height coordinate information  803  and  804 . 
     As shown in a image  820  of  FIG. 8 , the processor may generate a synthesis image by combining the first image with the second image by using the overlapped region between the first image and the second image and combining the second image with the third image by using the overlapped region between the second image and the third image. 
       FIG. 9A  explains a screen image that is output to a medical image processing apparatus and displays matching accuracy, according to an embodiment. 
     The medical image processing apparatus  650  may acquire a first image  901  corresponding an upper part of an object, a second image  902  corresponding a torso part of the object, and a third image  903  corresponding a lower part of the object. As shown in a synthesis image  910  of  FIG. 9A , an overlapped region  904  exists between the first image  901  and the second image  902 , and an overlapped region  905  exists between the second image  902  and the third image  903 . The medical image processing apparatus  650  may generate the synthesis image  910  by overlapping respective overlapping regions of images. The medical image processing apparatus  650  may display the synthesis image  910  and matching accuracy. 
     Information of the matching accuracy may include at least one of information about a length of the overlapped region  904  between the first image  901  and the second image  902 , information about a length of the overlapped region  905  between the second image  902  and the third image  903 , information about a location of the overlapped region  904  on the synthesis image  910 , information about locations of the second image  902  and the third image  903  on the synthesis image  910 , information about a matching accuracy probability of the overlapped region  904  between the first image  901  and the second image  902 , and information about a matching accuracy probability of the overlapped region  905  between the second image  902  and the third image  903 . The matching accuracy representing a match rate of the respective overlapping regions of the plurality of images may be expressed in percentage. It will be understood by one of ordinary skill in the art to which this embodiment pertains that the information of the matching accuracy may include other matching accuracy information of the synthesis image  910  in addition to the aforementioned information. 
     As shown in the synthesis image  910  of  FIG. 9A , the medical image processing apparatus  650  may display a marker  906  indicating the location of the overlapped region  904  between the first image  901  and the second image  902 , information  907 - 1  representing that the matching accuracy between the first image  901  and the second image  902  is 70%, and information  907 - 2  representing that the length of the overlapped region  904  is 5.2 cm. 
     The medical image processing apparatus  650  may also display a marker  908  indicating the location of the overlapped region  905  between the second image  902  and the third image  903 , information  909 - 1  representing that the matching accuracy between the second image  902  and the third image  903  is 100%, and information  909 - 2  representing that the length of the overlapped region  905  is 3.5 cm. 
       FIG. 9B  explains a screen image that is output to a medical image processing apparatus and displays matching accuracy, according to another embodiment. 
     A synthesis image  920  of  FIG. 9B  is the same as the synthesis image  910  of  FIG. 9A . A description of  FIG. 9B  that is the same as given above with reference to  FIG. 9A  will not be repeated herein. Reference numerals shown in the synthesis image  910  of  FIG. 9A  are equally applied to the synthesis image  920  of  FIG. 9B , and thus repeated descriptions thereof will be omitted. 
     When overlapping regions corresponding to a predetermined part of an object on a plurality of images match with each other, the medical image processing apparatus  650  may display information representing that matching between the plurality of images has succeeded. When the overlapped regions corresponding to the predetermined part of the object on the plurality of images mismatch with each other, the medical image processing apparatus  650  may display information representing that matching between the plurality of images has failed. 
     The medical image processing apparatus  650  may distinguish the case where a first region of a first image and a second region of a second image corresponding to the predetermined part of the object match with each other from the case where the first region of the first image and the second region of the second image mismatch with each other, and distinguishably set and display at least one of a color, shape, and pattern of a marker representing a location of an overlapped region between the first image and the second image. 
     Referring to the synthesis image  920  of  FIG. 9B , when respective overlapped regions  904  of the first image  901  and the second image  902  do not match with each other, the medical image processing apparatus  650  may display the marker  906 , representing the location of the overlapped regions  904 , in red, or change and display the pattern of the marker  906 . On other hand, when respective overlapped regions  905  of the second image  902  and the third image  903  match with each other, the medical image processing apparatus  650  may display the marker  908 , representing the location of the overlapped regions  905 , in blue. The above disclosure is only an example, and it will be understood by one of ordinary skill in the art to which this disclosure pertains that a marker may be displayed in various other manners according to a match or a mismatch between respective overlapped regions of a plurality of images. 
       FIG. 10A  explains a UI screen image via which a medical image processing apparatus corrects a synthesis image, according to an embodiment. 
     Referring to  FIG. 10A , the medical image processing apparatus  650  may receive an input of selecting a button  1001 , via a screen image  1010  on which the synthesis image is displayed. In response to the input of selecting the button  1001 , the medical image processing apparatus  650  may change the screen image  1010 , on which the synthesis image is displayed, to a UI screen image  1020  for correcting the synthesis image, and display the UI screen image  1020 . 
     The UI screen image  1020  may include a magnified image of an overlapped region  1021  between the first image and the second image and icons  1022  for manipulating the first image or the second image. The medical image processing apparatus  650  may receive an input of manipulating the first image or the second image, from a user via the UI screen image  1020 . For example, the medical image processing apparatus  650  may receive an input of correcting a section of an overlapped region between the first image and the second image, and may receive an input of adjusting a magnification ratio of the first image or the second image. The medical image processing apparatus  650  may correct the first or second image based on the user input, and re-generate a synthesis image by using a result of the correction. 
       FIG. 10B  explains a UI screen image via which a medical image processing apparatus corrects a synthesis image, according to another embodiment. 
     The medical image processing apparatus  650  may change the screen image  1010  of  FIG. 10A , on which the synthesis image is displayed, to a UI screen image  1030  for correcting the synthesis image, and display the UI screen image  1030 . 
     A user may visually recognize some information from the UI screen image  1030  displayed by a display and may input a command or data via the UI screen image  1030 . The UI screen image  1030  of  FIG. 10B  may include a synthesis image  1031 , a first image  1032 , a second image  1033 , a third image  1034 , and a magnified image  1035  of an overlapped region between the first image  1032  and the second image  1033 . The UI screen image  1030  of  FIG. 10B  may include an icon  1036  used to manipulate the images displayed on the UI screen image  1030  or to correct the overlapped region between the first image  1032  and the second image  1033  on the magnified image  1035 . 
     The UI screen image  1030  may include a touchpad coupled to a display panel included in the display. In this case, the UI screen image  1030  may be displayed on the display panel. 
     A UI may receive an input of correcting the range of an overlapped region between a first image and a second image or an input of adjusting magnification ratios of the first image and the second image, via a hand or a user or a physical tool (for example, a stylus pen) of the user. The medical image processing apparatus  650  may correct the first or second image based on the user input, and re-generate a synthesis image by using a result of the correction. 
       FIG. 11  explains an operation of an X-ray imaging apparatus according to an embodiment. 
     The X-ray imaging apparatus may include a device that generates an X-ray, and a device that detects an X-ray and converts the X-ray to an image. Examples of the X-ray imaging apparatus include a ceiling type X-ray imaging apparatus and a U-arm type X-ray imaging apparatus. 
     In the ceiling type X-ray imaging apparatus, an X-ray generating device is fixed to a ceiling. The ceiling type X-ray imaging apparatus operates widely and easily accesses a patient because of a high operational flexibility. 
     As shown in  FIG. 11 , a U-arm type X-ray imaging apparatus  1100  includes a source  1106  that generates an X ray and a detector  1107  that detects an X ray, and the source  1106  and the detector  1107  are fixed to an arm  1104  connected to an arm stand on the ground. The U-arm type X-ray imaging apparatus  1100  occupies a small space and is cheap in terms of equipment prices and installation costs, compared with ceiling type X-ray imaging apparatuses. However, since the source  1106  and the detector  1107  in the U-arm type X-ray imaging apparatus  1100  are connected together by the arm  1104 , motions of the source  1106  and the detector  1107  are restricted. 
     Referring to  FIG. 11 , the arm  1104  included in the U-arm type X-ray imaging apparatus  1100  may rotate with respect to a support  1101  as indicated by an arrow  1102 , and may move vertically as indicated by an arrow  1105 . The detector  1107  located on an end of the arm  1104  may linearly move as indicated by an arrow  1103 , in correspondence with the rotation or vertical motion of the arm  1104 . 
       FIG. 12A  is a block diagram of a structure of an X-ray imaging apparatus  1200  according to an embodiment. 
     The X-ray imaging apparatus  1200  may include a source  1210 , a detector  1220 , a processor  1230 , and a display  1240 . It will be understood by one of ordinary skill in the art to which this embodiment pertains that the X-ray imaging apparatus  1200  may include other general-use components in addition to the components illustrated in  FIG. 12A . 
     The X-ray imaging apparatus  1200  of  FIG. 12A  may be the same as the X-ray apparatus  100  of  FIG. 1 . In detail, the source  1210 , the detector  1220 , the processor  1230 , and the display  1240  of the X-ray imaging apparatus  1200  of  FIG. 12A  may respectively correspond to the X-ray radiator  120 , the detector  130 , the controller  150 , and the output unit  141  of the X-ray apparatus  100  of  FIG. 1 . A description of  FIG. 12A  that is the same as given above with reference to  FIG. 1  will not be repeated herein. A structure of the X-ray imaging apparatus  1200  of  FIG. 12A  will now be described. 
     The source  1210  may radiate an X-ray to an object, and the detector  1220  may detect an X-ray transmitted by the object. 
     The processor  1230  may control a location of at least one of the source  1210  and the detector  1220 . For example, when the X-ray imaging apparatus  1200  is a U-arm type X-ray imaging apparatus  1200 , the source  1210  and the detector  1220  may be physically coupled to an arm. The processor  1230  may control an angle of the arm in order to control the locations of the source  1210  and the detector  1220 . The processor  1230  may also control an incidence angle of an X-ray radiated by the source  1210 . The processor  1230  may acquire an image captured based on the location of the source  1210  and that of the detector  1220 . The processor  1230  may acquire error information of an image due to at least one of location errors of the source  1210  and the detector  1220 . 
     Before the processor  1230  controls the location of the source  1210  or the detector  1220 , location information according to a location of each component of the X-ray imaging apparatus  1200  is necessary, and reference location information needs to be set. For example, the reference location information may include, but is not limited to, coordinate system information (x axis, y axis, and z axis) of a place on which the X-ray imaging apparatus  1200  is mounted, a height and a width of the place on which the X-ray imaging apparatus  1200  is mounted, an inclination of a bottom of the place on which the X-ray imaging apparatus  1200  is mounted, Source to Image Distance (SID) information, and Source to Object Distance (SOD) information. Setting of the reference location information is referred to as calibration. Since calibration is performed with an actually measured value, an error may exist in the actually measured value. Since the X-ray imaging apparatus  1200  sensitively reacts with even a change in external environments, an error may also be generated due to even external factors. An error of calibration may be caused by a location error of the X-ray imaging apparatus  1200 . 
     The processor  1230  may generate a predicted image based on the location of the source  1210  and that of the detector  1220 , compare the captured image with the predicted image, and acquire error information of the captured image according to a result of the comparison. The predicted image needs to be captured based on the location of the source  121 , the location of the detector  1220 , and a location of the object. In contrast with the predicted image, the captured image is an actually captured image in which a location error of the source  121 , a location error of the detector  1220 , and a location error of the object have been reflected. 
     The processor  1230  may correct at least one of the location errors of the source  1210  and the detector  1220 , based on error information of a first image and error information of a second image. 
     The display  1240  may display information about correction of at least one location error, based on an image and error information of the image. For example, the display  1240  may display a UI screen image including information used to correct at least one of a source and a detector. 
     The processor  1230  may acquire a first image and a second image captured based on correction of location error of the at least one of the source and the detector. The processor  1230  may generate a synthesis image by overlapping a first region of the first image and a second region of the second image corresponding to a predetermined region of the object. The display  1240  may display the generated synthesis image. 
     Te X-ray imaging apparatus  1200  may include a central processor to control overall operations of the source  1210 , the detector  1220 , the processor  1230 , and the display  1240 . The central processor may be implemented by an array of a plurality of logic gates, or by a combination of a general-use microprocessor and a memory in which a program to be executed by the general-use microprocessor is stored. 
       FIG. 12B  is a block diagram of a structure of an X-ray imaging apparatus  1205  according to another embodiment. 
     The X-ray imaging apparatus  1205  may include a source  1250 , a detector  1260 , a processor  1270 , a display  1280 , and an input unit  1290 . It will be understood by one of ordinary skill in the art to which this embodiment pertains that the X-ray imaging apparatus  1205  may include other general-use components in addition to the components illustrated in  FIG. 12B . 
     The X-ray imaging apparatus  1205  of  FIG. 12B  may further include the input unit  1290 , compared with the X-ray imaging apparatus  1200  of  FIG. 12A . The source  1250 , the detector  1260 , the processor  1270 , and the display  1280  of the X-ray imaging apparatus  1205  of  FIG. 12B  respectively correspond to the source  1210 , the detector  1220 , the processor  1230 , and the display  1240  of the X-ray imaging apparatus  1200  of  FIG. 12A . 
     The input unit  1290  of the X-ray imaging apparatus  1205  of  FIG. 12B  may correspond to the input unit  142  of the X-ray apparatus  100  of  FIG. 1  or the input unit  112  of the workstation  110  of  FIG. 1 . A description of  FIG. 12B  that is the same as given above with reference to  FIGS. 1 and 12A  will not be repeated herein. The structure of the X-ray imaging apparatus  1205  of  FIG. 12B  will now be described. 
     The input unit  1290  refers to a device via which a user inputs data for controlling the X-ray imaging apparatus  1205 . The input unit  1290  may include, but is not limited to, hardware structures such as a keypad, a mouse, a touch panel, a touch screen, a track ball, and a jog switch. 
     The input unit  1290  may receive a user input of correcting at least one of location errors of the source  1250  and the detector  1260 . The processor  1270  may correct the at least one location error by changing at least one of the locations of the source  1250  and the detector  1260 , based on the user input. 
     The processor  1270  may acquire a first image captured based on a first location of the source  1250  and a first location of the detector  1260 . The processor  1270  may acquire error information of the first image due to at least one of respective location errors of the source  1250  and the detector  1260 . The processor  1270  may determine a magnification ratio of the first image, which is captured based on the first location of the source  1250  and the first location of the detector  1260 . For example, the processor  1270  may determine the magnification ratio of the first image by using a distance between the source  1250  and the detector  1260  and a distance between the source  1250  and an object. The magnification ratio of the first image may be calculated using Equation 1 below. The distance between the source  1250  and the detector  1260  may be calculated from the respective locations of the source  1250  and the detector  1260 . The distance between the source  1250  and the object may be calculated from the respective locations of the source  1250  and the object. 
     Math FIG.  1   
     
       
         
           
             
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     It will be understood by one of ordinary skill in the art to which this embodiment pertains that the magnification ratio of the first image may be calculated using other variables than Math  1 . 
     The processor  1270  may generate a first predicted image by predicting an image that is to be captured based on the first location of the source  1250 , the second location of the detector  1260 , and the location of the object. 
     The processor  1270  may compare the first image with the first predicted image and acquire error information of the first image. 
     The input unit  1290  may generate a UI screen image for receiving a command or data from a user, and the display  1280  may display the UI screen image. The display  1280  may display a UI screen image for correcting at least one of the location errors of the source  1250  and the detector  1260 . An acquired image and error information of the acquired image may be displayed on the UI screen image. 
     For example, the input unit  1290  may receive a user input of moving the first image or the second image based on an overlapped region between the first image and the second image. In detail, when an overlapped region between the first image and the second image exceeds a reference overlapped region, the input unit  1290  may receive a user input of moving the first image (or the second image) so that the overlapped region matches with the reference overlapped region. This will be described later in detail with reference to  FIGS. 18A-19 . 
     As another example, the input unit  1290  may receive a user input for correcting an error due to a difference between the magnification ratios of a captured image and a predicted image. The processor  1270  may detect the error due to the difference between the magnification ratios of the captured image and the predicted image. The processor  1270  may correct the magnification ratio of the captured image to the magnification ratio of the predicted image, based on the user input. 
     In detail, the input unit  1290  may receive a user input of correcting the magnification ratio of the first image to a magnification ratio of a predicted image for the first image and correcting the magnification ratio of the second image to a magnification ratio of a predicted image for the second image. In more detail, when the magnification ratio of the first image is greater than the magnification ratio of the predicted image for the first image, the input unit  1290  may receive a user input of reducing the magnification ratio of the first image. This will be described later in detail with reference to  FIGS. 20A and 20B . 
     As another example, the processor  1270  may detect a region of a collimator corresponding to an X-ray irradiated region of the collimator from the acquired image. The collimator adjusts a region irradiated with an X-ray. The processor  1270  may acquire preset information. The preset information may include information about the area of a preset region of the collimator and the central point of the detector  1260 . The processor  1270  may acquire the information about the area of the preset region of the collimator and the central point of the detector  1260  from the captured image, and compare information about the area of the collimator region and the central point of the collimator region with the preset information to thereby acquire error information of the captured image. In other words, the processor  1270  may compare the area of the collimator region with the area of the preset collimator region and the central point of the collimator region with the central point of the detector  1260  to thereby acquire the error information of the captured image. The display unit  1280  may display error information about the collimator region. 
     The input unit  1290  may receive at least one of a user input of adjusting the area of the collimator region and a user input of adjusting the central point of the collimator region. The processor  1270  may adjust at least one of the area of the collimator region and the central point of the collimator region according to the received user input. In detail, the processor  1270  may move the central point of the collimator region to the central point of the detector  1260  and adjust the area of the collimator region to be equal to the area of the preset collimator region, based on the user input. This will be described later in detail with reference to  FIGS. 21-22B . 
     As another example, the processor  1270  may detect a collimator region corresponding to the X-ray irradiated region of the collimator from the captured image. The processor  1270  may acquire first captured coordinate values representing coordinate values of a plurality of vertices of the collimator region from the captured image, and may calculate first predicted coordinate values representing predicted coordinate values of the plurality of vertices of the collimator region from a preset collimator region on the collimator, based on the locations of the source  1250  and the detector  1260 . The processor  1270  may compare the first predicted coordinate values with the first captured coordinate values to determine the error information of the captured image. The display unit  1280  may display error information about the collimator region. 
     The input unit  1290  may receive a user input of moving the collimator region so that the first captured coordinate values are identical with the first predicted coordinate values, based on the error information. The processor  1270  may control the source  1250  to move the collimator region based on the user input. This will be described later in detail with reference to  FIGS. 23 and 24 . 
     The X-ray imaging apparatus  1205  may further include a memory (not shown) and a communicator (not shown). The memory (not shown) may store, for example, data related with a driving range and coordinate information of the X-ray imaging apparatus  1205  (for example, a driving range of the arm in the U-arm type X-ray imaging apparatus  1205  and coordinate information of a place on which the X-ray imaging apparatus  1205  is mounted) and data transmitted from an external apparatus to the X-ray imaging apparatus  1205 . The memory may also store X-ray images related with the object. 
     The processor  1270  may control the object to be photographed based on the driving range of the X-ray imaging apparatus  1205  and location information of the place on which the X-ray imaging apparatus  1205  is mounted (for example, coordinate system information (x axis, y axis, and z axis) of the place on which the X-ray imaging apparatus  1205  is mounted, the height and width of the place on which the X-ray imaging apparatus  1205  is mounted, and the inclination of the bottom of the place on which the X-ray imaging apparatus  1205  is mounted, the SID information, and the SOD information), and component location information of the X-ray imaging apparatus  1205  (for example, the locations of the source  1250  and the detector  1260 ). The processor  1270  may correct the driving range and location information of the X-ray imaging apparatus  1205 , based on the at least one of the location errors of the source  1250  and the detector  1260 . For example, the processor  1270  may correct the coordinate system of the X-ray imaging apparatus  1205  by acquiring an error of the coordinate system of the X-ray imaging apparatus  1205  from the location errors of the source  1250  and the detector  1260 . The memory may store the corrected driving range and the corrected location information. The processor  1270  may acquire images captured using the corrected driving range, the corrected location information, and at least one of the location errors of the source  1250  and the detector  1260  of a corrected X-ray imaging apparatus  1205 . The processor  1270  may improve a matching rate of acquired images by combining the acquired images. 
     The communicator may receive data from the external apparatus and/or transmit data to the external apparatus. The communicator may transmit, for example, an image acquired according to location error correction of the X-ray imaging apparatus  1205  and location information of the X-ray imaging apparatus  1205  to an external apparatus or receive images related with the object from the external apparatus. 
     The X-ray imaging apparatus  1205  may include a central processor to control overall operations of the source  1250 , the detector  1260 , the processor  1270 , the display  1280 , and the input unit  1290 . The central processor may be implemented by an array of a plurality of logic gates, or by a combination of a general-use microprocessor and a memory in which a program to be executed by the general-use microprocessor is stored. It will also be understood by one of ordinary skill in the art to which this embodiment pertains that the central processor may be implemented by other types of hardware. 
     Various operations or applications that an X-ray imaging apparatus executes will now be described. However, matters to be clearly understood and expected by one of ordinary skill in the art to which the present invention pertains may be understood by typical implementations even when none of the sources  1210  and  1250 , the detectors  1220  and  1260 , the processors  1230  and  1270 , the displays  1240  and  1280 , and the input unit  1290  is specified, and the scope of the present invention is not limited by the titles or physical/logical structures of specified components. 
       FIG. 13  is a flowchart of a method of operating an X-ray imaging apparatus, according to an embodiment. 
     An operation of the X-ray imaging apparatus  1200  will now be described, but this description is not be limited to the X-ray imaging apparatus  1200  but may be equally applied to the X-ray imaging apparatus  1205 . 
     In operation S 1310  of  FIG. 13 , the X-ray imaging apparatus  1200  may control a location of at least one of a source that radiates an X ray to an object and a detector that detects an X ray transmitted by the object. 
     In operation S 1320 , the X-ray imaging apparatus  1200  may acquire an image captured based on respective locations of the source and the detector. 
     In operation  51330 , the X-ray imaging apparatus  1200  may acquire error information of the captured image due to an error of the location of the at least one of the source and the detector. 
     In operation S 1340 , the X-ray imaging apparatus  1200  may display information about correction of the location error of the at least one of the source and the detector, based on the captured image and the error information of the captured image. 
     There may be provided a computer-readable recording medium having recorded thereon a program for the method of executing operations S 1310 -S 1340  described above with reference to  FIG. 13 . 
       FIG. 14  explains a structure of an X-ray imaging apparatus according to an embodiment. 
     As shown in  FIG. 14 , a U-arm type X-ray imaging apparatus may include a source  1410 , a detector  1420 , an arm  1430 , a support  1440 , and a processor (not shown). The U-arm type X-ray imaging apparatus may further include an arm connector  1435  connecting the support  1440  to the arm  1430 , a source connector  1415  connecting the source  1410  to the arm  1430 , and a detector connector  1425  connecting the detector  1420  to the arm  1430 . The source connector  1415 , the detector connector  1425 , and the arm connector  1435  may serve as rotation centers about which the source  1410 , the detector  1420 , and the arm  1430  rotate, respectively. 
       FIG. 15A  explains a photographing operation of an X-ray imaging apparatus according to an embodiment. 
       FIG. 15A  illustrates a stepping type photographing operation of the X-ray imaging apparatus  1200 . The stepping type photographing operation is to capture an X-ray image while equally moving a source  1501  and a detector  1502 . 
     Referring to  FIG. 1510 , according to the stepping type photographing method, an X ray is emitted from the source  1501  to the detector  1502  in a direction perpendicular to an X-ray detection surface of the detector  1502 . The X-ray imaging apparatus  1200  performs first photography on an object  1515  by detecting an X-ray transmitted by the object  1515 . 
     When the first photography with respect to the object  1515  is concluded, the X-ray imaging apparatus  1200  moves the detector  1502  and the source  1501  and performs second photography as shown in  FIG. 1520 . During the first photography and the second photography, a radiation angle and distance of the X ray from the source  1501  to the detector  1502  may be constantly maintained, and only heights of the source  1501  and the detector  1502  from the ground may be changed. 
       FIG. 15B  illustrates a synthesis image generated by an X-ray imaging apparatus. 
     The synthesis image of  FIG. 15B  is a single image obtained by combining images (an image captured by the first photography and an image captured by the second photography) captured according to the stepping type photographing method described above with reference to  FIG. 15A . 
     In this case, the X-ray imaging apparatus  1200  may acquire an image of a region that is different from a region on an object desired to be acquired, due to a location error of the X-ray imaging apparatus  1200 . When the X-ray imaging apparatus  1200  stitches erroneous images, a mismatched region  1530  is generated as shown in  FIG. 15B . Accordingly, by correcting the location error of the X-ray imaging apparatus  1200 , a match rate and an image quality of the synthesis image obtained by combining the plurality of images may improve. 
       FIG. 16A  explains a photographing operation of an X-ray imaging apparatus according to an embodiment. 
     Referring to  FIG. 16A , in the X-ray imaging apparatus  1200 , a source emits an X ray to an object, and a detector detects a difference between intensities of X-rays respectively transmitted by the object, thereby acquiring an image. 
     As shown in  FIG. 16A , the X-ray imaging apparatus  1200  may control locations of the source and the detector so that a plurality of images are captured to be overlapped with one another by a predetermined length. The source and the detector may be connected to an arm, and the X-ray imaging apparatus  1200  may control the locations of the source and the detector by controlling the angle of the arm. The term “angle of an arm” denotes an angle formed by the arm with respect to an X-ray detection surface of the detector. The X-ray imaging apparatus  1200  may control the angle of the arm to be equal to an X-ray radiating angle of the source. 
     For example, the X-ray imaging apparatus  1200  may photograph the object by increasing the angle of the arm 10 degrees at a time with respect to a first location of the detector. As the angle and height of the arm are controlled, the detector is moved farther from the object, and thus the detector is pushed back. 
     As shown in  FIG. 16A , the X-ray imaging apparatus  1200  acquires a first image  1604  at the first location of the detector, acquires a second image  1605  at a second location of the detector, and acquires a third image  1606  at a third location of the detector. The detector being pushed back when the detector is moved from the first location to the second location is indicated by reference numeral  1607 , and the detector being pushed back when the detector is moved from the second location to the third location is indicated by reference numeral  1608 . As the object and the detector become distant from each other, a region of the object detected by the detector enlarges. As the object and the detector become closer to each other, the region of the object detected by the detector diminishes. The X-ray imaging apparatus  1200  may generate a single synthesis image  1607  by combining the first image  1604 , the second image  1605 , and the third image  1606  with one another. 
       FIG. 16B  illustrates a synthesis image generated by an X-ray imaging apparatus. 
     The synthesis image  FIG. 16B  is a single image obtained by combining images (a first image captured at a first location of a detector and a second image captured at a second location of the detector) captured according to the photographing method described above with reference to  FIG. 16A . 
     In this case, the X-ray imaging apparatus  1200  may acquire an image of a region that is different from a region on an object desired to be acquired, due to a location error of the X-ray imaging apparatus  1200 . In detail, although the X-ray imaging apparatus  1200  controls the detector to be positioned at the first location, the X-ray imaging apparatus  1200  actually positions the detector at a location slightly deviating from the first location, thereby generating an error. Thus, due to the location error of the X-ray imaging apparatus  1200 , a magnification ratio of a predicted image to be acquired by positioning the detector at the first location is different from a magnification ratio of an actual image. When the X-ray imaging apparatus  1200  stitches erroneous images, a mismatched region  1620  is generated as shown in  FIG. 16B . Accordingly, by correcting the location error of the X-ray imaging apparatus  1200 , a match rate and an image quality of the synthesis image obtained by combining the plurality of images may be improved. 
       FIG. 17A  is a flowchart of a method of operating an X-ray imaging apparatus, according to another embodiment. 
     In operation S 1710  of  FIG. 17A , the X-ray imaging apparatus  1205  may receive a user input of correcting at least one of the location errors of the source and the detector from a UI screen image. 
     In operation S 1720 , the X-ray imaging apparatus  1205  may correct the at least one of the location errors of the source and the detector, based on the user input. The X-ray imaging apparatus  1205  may correct the at least one location error by changing at least one of the locations of the source and the detector, based on the user input. 
       FIG. 17B  is a flowchart of a method of operating an X-ray imaging apparatus, according to another embodiment. 
     In operation  51730  of  FIG. 17B , the X-ray imaging apparatus  1205  may acquire a first image and a second image of the object, based on correction of the at least one of the locations of the source and the detector. The first image and the second image are images in which the location error correction of the X-ray imaging apparatus  1205  has been reflected. 
     In operation S 1740 , the X-ray imaging apparatus  1205  may generate a synthesis image by overlapping a first region of the first image and a second region of the second image corresponding to a predetermined region of the object. In this case, the X-ray imaging apparatus  1205  may generate a synthesis image having no mismatched regions and having an improved quality. 
     In operation  51750 , the X-ray imaging apparatus  1205  may display the synthesis image. 
     There may be provided a computer-readable recording medium having recorded thereon a program for executing the methods of operating the X-ray imaging apparatus  1205  described above with reference to  FIGS. 17A and 17B . 
       FIG. 18A  explains a method of correcting a location error by using a plurality of captured images via a UI screen image, according to an embodiment. 
     The X-ray imaging apparatus  1205  may correct a location error generated by the X-ray imaging apparatus  1205  by using a first image and a second image acquired by the X-ray imaging apparatus  1205 . The X-ray imaging apparatus  1205  may display a UI screen image for correcting the location error. 
     Referring to  FIG. 18A , the X-ray imaging apparatus  1205  may acquire a first image  1801  and a second image  1802  according to the photographing method described above with reference to  FIG. 15A . The X-ray imaging apparatus  1205  controls locations of a source and a detector and photographs an object based on the controlled locations. 
     The X-ray imaging apparatus  1205  photographs the object such that an overlapped region exists between images to achieve continuity of the images. In this case, the X-ray imaging apparatus  1205  may set the length of the overlapped region to be 5 mm, and acquire a first image  1801  and a second image  1802  so that the overlapped region therebetween is 5 mm. When the length of the overlapped region is set to exceed a predetermined value, the number of algorithm calculations during matching between images increases. As the number of overlapped regions increases, the number of joints of a spine bone increases. Thus, the risk of misdiagnosis exists. Thus, the X-ray imaging apparatus  1205  may set a reference value for the overlapped region. When a value of the overlapped region exceeds the reference value, the X-ray imaging apparatus  1205  may correct the overlapped region automatically or manually (for example, a user input). 
     Referring to  FIG. 18A , due to a location error of the X-ray imaging apparatus  1205 , the length of the overlapped region between the first image  1801  and the second image  1802  may exceed 5 mm. The X-ray imaging apparatus  1205  may receive a user input of correcting the location error, via a UI screen image. 
     The X-ray imaging apparatus  1205  may receive an input of correcting a section of the overlapped region between the first image  1801  and the second image  1802 . The UI screen image may include an icon  1807  for manipulating the first image  1801  and the second image  1802 . 
     The X-ray imaging apparatus  1205  may receive a manipulation signal generated due to various input tools or a user touch input. The X-ray imaging apparatus  1205  may receive an input of moving the second image  1802  by a hand or a physical tool of a user. Referring to  FIG. 18A , a UI may receive an input  1806  of moving the second image  1802  downwards by 5 mm. The X-ray imaging apparatus  1205  may move the second image  1802  downwards by 5 mm so that respective overlapping regions of the first image  1801  and the second image  1802  generated due to the location error of the X-ray imaging apparatus  1205  may match with each other. 
     By performing correction via the UI screen image so that the overlapping regions of the first image  1801  and the second image  1802  match with each other, the X-ray imaging apparatus  1205  may correct the location error of the X-ray imaging apparatus  1205  and prevent a location error from being generated by the next photography. 
       FIG. 18B  explains a method of correcting a location error by using a plurality of captured images via a UI screen image, according to another embodiment. 
     Referring to  FIG. 18B , the X-ray imaging apparatus  1205  may acquire a first image  1811  and a second image  1812  according to the photographing method described above with reference to  FIG. 15A . 
     Referring to  FIG. 18B , due to a location error of the X-ray imaging apparatus  1205 , the length of an overlapped region between the first image  1811  and the second image  1812  may be less than a reference length by 4 mm. The reference length is a length of the overlapped region that is minimally necessary for matching the first image  1811  with the second image  1810 . As the length of the overlapped region is less than a predetermined value or the overlapped region becomes smaller, the same part of an object is not included in the overlapped region, and thus a case where matching is impossible may occur. Thus, the X-ray imaging apparatus  1205  may set a reference value for the overlapped region. When a value of the overlapped region is less than the reference value, the X-ray imaging apparatus  1205  may correct the overlapped region automatically or manually (for example, a user input). 
     The X-ray imaging apparatus  1205  may receive an input of correcting a section of the overlapped region between the first image  1811  and the second image  1812 . The X-ray imaging apparatus  1205  may receive an input  1816  of moving the second image  1812  upwards by 4 mm. The X-ray imaging apparatus  1205  may move the second image  1812  upwards by 4 mm so that respective overlapping regions of the first image  1811  and the second image  1812  generated due to the location error of the X-ray imaging apparatus  1205  may match with each other. 
       FIG. 19  explains a synthesis image in which location error correction of an X-ray imaging apparatus has been reflected, and a synthesis image in which location error correction of an X-ray imaging apparatus has not yet been reflected, according to an embodiment. 
     The X-ray imaging apparatus  1205  may acquire an X-ray image of an object by combining a plurality of X-ray images with one another. The X-ray imaging apparatus  1205  may acquire a first image captured based on a first location of a source and a first location of a detector, and a second image captured based on a second location of the source and a second location of the detector. 
     Due to a location error of the X-ray imaging apparatus  1205 , the first image or the second image may have an error. The location error of the X-ray imaging apparatus  1205  may be generated due to errors between respective actual locations of the source and the detector and respective predicted locations of the source and the detector. The location error of the X-ray imaging apparatus  1205  may also be generated due to an error of an Image to Object Distance (IOD) or may be generated from the fact that the location of the object is not fixed. 
     Since the first image or the second image has an error, even when the first image and the second image are synthesized by overlapping respective overlapping regions of the first image and the second image, an overlapped region  1911  between the first image and the second image has a mismatched region. The X-ray imaging apparatus  1205  may display, on a screen image  1910 , a synthesis image including a mismatched region and information representing that matching between the first image and the second image has failed. 
     As described above with reference to  FIGS. 18A and 18B , the X-ray imaging apparatus  1205  may correct the location error of the X-ray imaging apparatus  1205  by using the first image and the second image. Due to the location error correction, the X-ray imaging apparatus  1205  may acquire a third image and a fourth image each having no location errors at the next photography. The X-ray imaging apparatus  1205  may acquire a matched synthesis image by overlapping respective overlapping regions of the third image and the fourth image. In other words, the X-ray imaging apparatus  1205  may acquire a synthesis image in which respective overlapping regions  1921  of the third image and the fourth image are matched with each other. The X-ray imaging apparatus  1205  may display, on a screen image  1920 , the matched synthesis image and information representing that matching between the third image and the fourth image has succeeded. 
       FIG. 20A  explains a method of correcting a location error by using a plurality of captured images via a UI screen image, according to another embodiment. 
     According to the photographing method described above with reference to  FIG. 16A , the X-ray imaging apparatus  1205  may control respective locations of a source and a detector and photograph an object based on the controlled locations to thereby acquire a first image  2001  and a second image  2002 . 
     As described above with reference to  FIG. 16A , the detector is pushed back according to an angle of an arm. Thus, images captured according to angles of the arm have different magnification ratios. 
     Theoretically, it is assumed that a first image captured according to a first angle of the arm has a first magnification ratio and a second image captured according to a second angle of the arm has a second magnification ratio. A magnification ratio may be calculated from a ratio of an SID to an SOD. However, due to a location error of the X-ray imaging apparatus  1205 , the first image may have another magnification ratio instead of the first magnification ratio, and the second image may have another magnification ratio instead of the second magnification ratio. The location error of the X-ray imaging apparatus  1205  may be generated due to errors between respective actual locations of the source and the detector and respective predicted locations of the source and the detector. The location error of the X-ray imaging apparatus  1205  may also be generated due to an error of an IOD. The location error of the X-ray imaging apparatus  1205  may also be generated due to the environments of an installation place of the X-ray imaging apparatus  1205  or a location error of a jig stopper that moves the object. 
     The X-ray imaging apparatus  1205  may receive a user input of correcting the location error of the X-ray imaging apparatus  1205 , via a UI screen image. The X-ray imaging apparatus  1205  may receive a user input of correcting the magnification ratio of the first image to a magnification ratio of a first predicted image for the first image and the magnification ratio of the second image to a magnification ratio of a second predicted image for the second image, and match the first image with the second image according to the user input. According to the corrections of the magnifications of the first and second images, the X-ray imaging apparatus  1205  may correct the location error of the X-ray imaging apparatus  1205 . 
     When the X-ray imaging apparatus  1205  matches the first image with the second image in response to a user input of making the magnification ratio of the first image identical to the magnification ratio of the second image, the X-ray imaging apparatus  1205  may correct the location error thereof. 
     The X-ray imaging apparatus  1205  may receive a user input of correcting the location error, via a UI screen image. The X-ray imaging apparatus  1205  may receive an input of correcting the magnification ratios of the first image and the second image. The UI screen image may include an icon for manipulating the first image and the second image. 
     The X-ray imaging apparatus  1205  may receive a manipulation signal generated due to various input tools or a user touch input. The X-ray imaging apparatus  1205  may receive an input of increasing or decreasing the magnification ratio of the first image or the magnification ratio of the second image by a hand or a physical tool of a user. 
     By performing correction such that the magnification ratios of the first image and the second image are identical to each other, the X-ray imaging apparatus  1205  may correct the location error of the X-ray imaging apparatus  1205  and prevent a location error from being generated by the next photography. 
       FIG. 20B  explains a synthesis image in which location error correction of an X-ray imaging apparatus has been reflected, and a synthesis image in which location error correction of an X-ray imaging apparatus has not yet been reflected, according to an embodiment. 
     According to the photographing method described above with reference to  FIG. 16A , the X-ray imaging apparatus  1205  may control respective locations of a source and a detector and photograph an object based on the controlled locations to thereby acquire a first image and a second image. 
     Due to a location error of the X-ray imaging apparatus  1205 , the first image or the second image may have a magnification error. Thus, when the X-ray imaging apparatus  1205  makes the magnification ratio of the first image identical to the magnification ratio of the second image and generates a synthesis image by overlapping a first region of the first image with a second region of the second image, a mismatched region may be generated in an overlapped region  2011  between the first image and the second image due to the location error of the X-ray imaging apparatus  1205 . 
     As described above with reference to  FIG. 20A , the X-ray imaging apparatus  1205  may correct the location error of the X-ray imaging apparatus  1205  by using the first image and the second image. Due to the location error correction, the X-ray imaging apparatus  1205  may acquire a third image and a fourth image each having no location errors at the next photography. The X-ray imaging apparatus  1205  may acquire a matched synthesis image by overlapping respective overlapping regions of the third image and the fourth image. In other words, the X-ray imaging apparatus  1205  may acquire a synthesis image in which respective overlapping regions  2021  of the third image and the fourth image are matched with each other. 
       FIG. 21  is a flowchart of a method of operating an X-ray imaging apparatus, according to an embodiment. In detail,  FIG. 21  is a flowchart of a method in which an X-ray imaging apparatus acquires error information of a captured image. 
     In operation  52110 , the X-ray imaging apparatus  1205  may detect a region of a collimator corresponding to an X-ray irradiated region of the collimator from the captured image. 
     In operation  52120 , the X-ray imaging apparatus  1205  may acquire information about the area of the collimator region and the central point of the collimator region, from the captured image. 
     In operation  52130 , the X-ray imaging apparatus  1205  may compare the information about the area of the collimator region and the central point of the collimator region with preset information about the area of the collimator region and the central point of a detector to thereby acquire the error information of the captured image. The central point of a detector may be a center value of a detector region in a coordinate system representing a location of the detector. 
     When an image is captured when the central point of the collimator region is not identical to the central point of the detector, a region of interest of an object may deviate from a photographing range. Thus, the X-ray imaging apparatus  1205  may receive a user input of correcting the central point of the collimator region and the central point of the detector to be identical to each other. The X-ray imaging apparatus  1205  may compare the area of the collimator region acquired from the captured image with the area of a preset collimator region and the central point of the collimator region acquired from the captured image with the central point of the detector and thus may acquire error information as a result of the comparison. 
       FIGS. 22A and 22B  explain a method of correcting a location error by using a captured image via a UI screen image, according to an embodiment. 
     Referring to  FIG. 22A , the X-ray imaging apparatus  1205  may compare a central point  2202  of a collimator with a central point  2203  of a detector and may display a result of the comparison on a screen image  2205 . The central point  2202  of the collimator is a central point of a region  2201  on an image that corresponds to an X-ray irradiated region of the collimator. In other words, the central point  2202  of the collimator may be a central point of a collimation blade. During capturing of an X-ray image, the X-ray image may be accurately captured only when the central point  2202  of the collimator is identical with the central point  2203  of the detector. 
     The X-ray imaging apparatus  1205  may receive at least one of a user input of adjusting the area of a collimator region and a user input of adjusting the central point of the collimator region, and may adjust at least one of the area of the collimator region and the central point of the collimator region according to the received user input. 
     The X-ray imaging apparatus  1205  may receive a user input of making the central point of the collimator region and the central point of the detector be identical to each other via a UI screen image. 
     In detail, the UI screen image may include an icon  1807  for setting a central point of the collimator region or moving the central point. The X-ray imaging apparatus  1205  may receive an input of correcting the central point of the collimator region to the central point of a preset collimator region by using a hand or a physical tool of a user. In detail, the X-ray imaging apparatus  1205  may receive an input of moving the central point  2202  of the collimator region to the central point of the preset collimator region. A user move the central point  2202  of the collimator region to the central point of the preset collimator region by using a drag-and-drop function of a stylus pen on the screen image  2205 . It will be understood by one of ordinary skill in the art to which this embodiment pertains that the central point  2202  of the collimator region may be moved to the central point of the preset collimator region according to other methods than the aforementioned method. 
     When a difference between the central point  2202  of the collimator and the central point  2203  of the detector is very small, the X-ray imaging apparatus  1205  may be leveled with the ground by moving the central point of the collimator. On the other hand, when a difference between the central point  2202  of the collimator and the central point  2203  of the detector is large, the X-ray imaging apparatus  1205  may be re-mounted to be leveled with the ground. 
     Referring to  FIG. 22B , the X-ray imaging apparatus  1205  may display a screen image  2212  on which a collimator region  2201  on an image corresponding to a collimator and a preset collimator region  2211  are displayed. During capturing of an X-ray image, the X-ray image may be accurately captured only when the area of the collimator region  2201  is identical with the area of the preset collimator region  2211 . 
     The X-ray imaging apparatus  1205  may make the area of the collimator region  2201  be identical with the area of the preset collimator region  2211  by making the central point of the collimator be identical with the central point of the detector and making the area of the collimator region  2201  be identical with the area of the preset collimator region  2211 . 
     The X-ray imaging apparatus  1205  may receive a user input of making the collimator region  2201  and the preset collimator region  2211  be identical to each other via a UI screen image. For example, a user may make the collimator region  2201  be identical with the preset collimator region  2211  by using a drag-and-drop function of a stylus pen on the screen image  2212 . It will be understood by one of ordinary skill in the art to which this embodiment pertains that the collimator region  2201  may be made identical with the preset collimator region  2211  according to other methods than the aforementioned method. 
     By making the collimator region  2201  and the preset collimator region  2211  be identical with each other, image precision of the X-ray imaging apparatus may improve. 
       FIG. 23  is a flowchart of a method of operating an X-ray imaging apparatus, according to an embodiment. In detail,  FIG. 23  is a flowchart of a method in which an X-ray imaging apparatus acquires error information of a captured image. 
     In operation  52310 , the X-ray imaging apparatus  1205  may detect a region of a collimator corresponding to an X-ray irradiated region of the collimator from the captured image. 
     In operation  52320 , the X-ray imaging apparatus  1205  may acquire first captured coordinate values representing coordinate values of a plurality of vertices of the collimator region from the captured image, and may also acquire first predicted coordinate values representing predicted coordinate values of the plurality of vertices of the collimator region. The first predicted coordinate values corresponding to the first captured coordinate values may be calculated from a preset collimator region on the collimator. 
     In operation  52330 , the X-ray imaging apparatus  1205  may acquire error information of the captured image by comparing the first predicted coordinate values with the first captured coordinate values. 
       FIG. 24  explains a method of correcting a location error by using a captured image via a UI screen image, according to an embodiment. 
     Referring to  FIG. 24 , the X-ray imaging apparatus  1205  may detect a collimator region corresponding an X-ray irradiated region of a collimator, and acquire first captured coordinate values  2401 ,  2402 ,  2403 , and  2404  representing coordinates of a plurality of vertices of the collimator region from the captured image. The X-ray imaging apparatus  1205  may acquire first predicted coordinate values representing predicted coordinate values of the plurality of vertices of the collimator region. In detail, the X-ray imaging apparatus  1205  may calculate the first predicted coordinate values corresponding to the first captured coordinate values from a preset collimator region on the collimator. The X-ray imaging apparatus  1205  may display the first captured coordinate values  2401 ,  2402 ,  2403 , and  2404  on a screen image, and may also display first predicted coordinate values  2411 ,  2412 ,  2413 , and  2414  of a plurality of vertices of the preset collimator region on the image screen. 
     The X-ray imaging apparatus  1205  may correct the location error of the X-ray imaging apparatus  1205  by moving the region of the collimator so that the first captured coordinate values  2401 ,  2402 ,  2403 , and  2404  are identical with the first predicted coordinate values  2411 ,  2412 ,  2413 , and  2414 . 
     The X-ray imaging apparatus  1205  may receive a user input of moving the region of the collimator so that the first captured coordinate values  2401 ,  2402 ,  2403 , and  2404  are identical with the first predicted coordinate values  2411 ,  2412 ,  2413 , and  2414 . 
     The above-described apparatus may be implemented by using a hardware component, a software component, and/or a combination of a hardware component and a software component. For example, the apparatus and the component described in the exemplary embodiments may be implemented by using one or more general-purpose computers or a special-purpose computers such as, for example, a processor, a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable array (FPA), a programmable logic unit (PLU), a microprocessor, or any device that may execute an instruction and respond thereto. 
     A processor may execute an operating system (OS) and one or more software applications executed on the OS. Also, the processor may access, store, manipulate, process, and generate data in response to execution of software. 
     For convenience of understanding, though description has been made to the case where one processor is used, a person of ordinary skill in the art will understand that the processor may include a plurality of processing elements and/or processing elements having a plurality of types. For example, the processor may include a plurality of processors, or one processor and one controller. Also, the processor may include a different processing configuration such as a parallel processor. 
     Software may include a computer program, a code, an instruction, or a combination of one or more of these, and configure the processor to operate as desired, or instruct the processor independently or collectively. 
     Software and/or data may be embodied permanently or temporarily in a certain type of a machine, a component, a physical device, virtual equipment, a computer storage medium or device, or a transmitted signal wave in order to allow the processor to analyze the software and/or data, or to provide an instruction or data to the processor. Software may be distributed on a computer system connected via a network, and stored and executed in a distributed fashion. Software and data may be stored in one or more non-transitory computer-readable recording media. 
     The methods according to exemplary embodiments may be embodied in the form of program commands executable through various computer means, which may be recorded on a non-transitory computer-readable recording medium. The non-transitory computer-readable recording medium may include program commands, data files, and data structures either alone or in combination. The program commands recorded on the non-transitory computer-readable recording medium may be those that are especially designed and configured for the inventive concept, or may be those that are known and available to computer programmers skilled in the art. 
     Examples of the non-transitory computer-readable recording medium include magnetic recording media such as hard disks, floppy disks, and magnetic tapes, optical recording media such as CD-ROMs and DVDs, magneto-optical recording media such as floptical disks, and hardware devices such as ROMs, RAMs, and flash memories that are especially configured to store and execute program commands. 
     Examples of the program commands include machine language codes that may be generated by a compiler, and high-level language codes that may be executed by a computer by using an interpreter. 
     The above hardware device may be configured to operate as one or more software modules in order to perform an operation of an exemplary embodiment, and vice versa. 
     Though the exemplary embodiments have been described by a limited number of exemplary embodiments and drawings, a person of ordinary skill in the art will make various modifications and changes from the above exemplary embodiments. For example, even when the described technologies are performed in an order different from the described method and/or components such as the described system, structure, apparatus, and circuit are coupled or combined in a form different from the described method, or replaced by other components or equivalents thereof, a proper result may be accomplished. 
     Therefore, the scope of the inventive concept should not be limited and determined by the described exemplary embodiments, but should be determined by not only the following claims but also equivalents thereof.