Radiographic imaging device for acquiring improved radiographic image and method for operating radiographic imaging device

Abstract

A radiographic image capturing device according to the present disclosure includes: an image output unit that outputs a first radiographic image included in continuous radiographic images obtained by radiographic imaging of a subject; an image brightness information extraction unit that obtains brightness information from the first radiation image; a first irradiation condition calculation unit that determines a first irradiation condition on the basis of the luminance information; an irradiation control unit that controls the dose of radiation on the basis of the first irradiation condition; a second irradiation condition calculation unit that determines a second irradiation condition on the basis of a second radiation image generated on the basis of the first irradiation condition when an imaging site of the subject is fixed; and a dose reduction unit that reduces or maintains a dose of radiation on the basis of the second irradiation condition.

Description

Technical Field

[0001] The present disclosure relates to a radiographic imaging device for acquiring improved radiographic images and an operating method of the radiographic imaging device. The radiographic imaging device determines irradiation conditions according to different methods when acquiring continuous radiographic images. Background Art

[0002] Radiographic imaging devices that achieve low doses are becoming increasingly important in medical imaging because they reduce the risk of side effects. These devices can achieve low doses using advanced software algorithms, improved hardware components, and new radiation sources.

[0003] Radiographic imaging devices that achieve low doses have limitations in the way they can produce images with reduced contrast and spatial resolution. As a result, detecting small lesions or abnormalities may become more difficult. In addition, low-dose imaging may not be suitable for certain types of imaging procedures that require high-dose imaging to visualize specific structures or abnormalities.

[0004] Furthermore, low-dose radiography equipment is relatively expensive, so accessibility may be limited. In addition, the implementation of new technologies and methods may require further education and expertise of radiographers and radiologists, making the adoption of low-dose imaging equipment difficult.

[0005] As one of the low-dose radiation imaging devices, the radiation imaging device is widely known as a device used during surgery and treatment by continuously irradiating the affected part of the human body and animal body with X-rays to obtain a fluoroscopic image of the affected part in real time. When a patient is operated on using a radiation imaging device, the irradiation conditions and image brightness are affected by objects other than the objects of interest such as the surgeon's hands and surgical tools, so there is a problem that the prescribed image brightness and level cannot be maintained. In addition, the existing automatic irradiation condition adjustment method uses irradiation conditions that can be used for various subjects, so the subject in actual shooting is irradiated with more radiation than the appropriate irradiation amount.

[0006] Nevertheless, since the risk of side effects can be reduced and patient safety can be improved by minimizing radiation exposure, it is necessary to use low-dose radiation imaging devices in medical imaging. Therefore, various studies are being conducted to realize low-dose radiation imaging devices. Summary of the invention

[0007] Problem that the invention aims to solve

[0008] The present disclosure relates to a radiographic imaging device that realizes low-dose radiographic images. More specifically, the radiographic imaging device minimizes the burden on patients and users by quickly acquiring low-dose radiographic images.

[0009] Means used to solve problems

[0010] According to the present disclosure, the radiation imaging device includes: an image output unit, which outputs a first radiation image obtained by radiation imaging of a subject and contained in a continuous radiation image; an image brightness information extraction unit, which obtains brightness information from the first radiation image; a first irradiation condition calculation unit, which determines a first irradiation condition based on the brightness information; an irradiation control unit, which controls the dose of radiation based on the first irradiation condition; a second irradiation condition calculation unit, which determines a second irradiation condition based on a second radiation image generated based on the first irradiation condition when the imaging part of the subject is fixed; and a dose reduction unit, which reduces or maintains the dose of radiation based on the second irradiation condition.

[0011] In the radiation imaging apparatus according to the present disclosure, a value of a radiation dose based on the first irradiation condition minus a radiation dose based on the second irradiation condition is less than or equal to 70% of the dose based on the first irradiation condition.

[0012] In the radiation imaging apparatus according to the present disclosure, when the dose is reduced by the dose reducing section, the first irradiation condition calculating section is disabled.

[0013] In the radiation imaging device according to the present disclosure, an improved current frame image is generated by cumulatively averaging pixel values ​​of a current frame image contained in a third radiation image output according to a dose reduced by a dose reducing unit and pixel values ​​of previous frame images contained in the third radiation image.

[0014] According to the present disclosure, the radiation imaging device also includes: an image post-processing unit that post-processes the third radiation image output according to the dose reduced by the dose reduction unit, and the image post-processing unit adjusts at least one of the brightness information and contrast information of the third radiation image similarly to at least one of the brightness information and contrast information of the second radiation image.

[0015] According to the present disclosure, a radiation imaging device includes: a radiation irradiation unit, which irradiates radiation to a subject; an image acquisition unit, which receives radiation irradiated from the radiation irradiation unit and passing through the subject to generate continuous radiation images; and a control unit, which controls the radiation irradiation unit and the image acquisition unit. The working method of the radiation imaging device includes: a step in which the control unit acquires brightness information based on a first radiation image contained in the continuous radiation images; a step in which, according to a first algorithm, a first irradiation condition is determined based on the brightness information; a step in which a dose of radiation is controlled based on the first irradiation condition; a step in which a second radiation image contained in the continuous radiation images and generated based on the first irradiation condition is acquired; a step in which movement or non-movement information indicating whether a photographing part of the subject is fixed is acquired; a step in which, when the movement or non-movement information indicates that the photographing part of the subject is fixed, a second irradiation condition is determined based on the second radiation image according to a second algorithm; a step in which a dose of radiation is controlled based on the second irradiation condition; and a step in which a third radiation image contained in the continuous radiation images and generated based on the second irradiation condition is acquired.

[0016] In the operating method of the radiation imaging device according to the present disclosure, the radiation dose based on the second irradiation condition is greater than or equal to 30% of the radiation dose based on the first irradiation condition.

[0017] In the operating method of the radiation imaging apparatus according to the present disclosure, a first algorithm for determining the first irradiation condition is different from a second algorithm for determining the second irradiation condition.

[0018] In the working method of the radiation imaging device according to the present disclosure, the step of acquiring a third radiation image includes: generating an improved current frame image by cumulatively averaging pixel values ​​contained in at least a portion of a current frame image contained in the third radiation image and pixel values ​​contained in at least a portion of a previous frame image contained in the third radiation image.

[0019] In the working method of the radiation imaging device according to the present disclosure, the step of acquiring a third radiation image includes: the step of generating a motion detection image, wherein the motion detection image includes motion detection information of each pixel of a differential image obtained by differentially obtaining a current frame image contained in the third radiation image and a previous frame image contained in the third radiation image; the step of generating a motion probability image based on the generated motion detection image and the motion detection image accumulated to the previous frame; and the step of mixing the current frame image and the previous frame image based on the motion probability image to generate an improved current frame image.

[0020] In the working method of the radiation imaging device according to the present disclosure, the step of generating a motion probability image includes: the step of generating a motion probability image by adding one or more of the motion detection image of the current frame and the motion detection images up to the previous frame, and the step of generating an improved current frame image includes: the step of variably determining the mixing ratio of the current frame image and the previous frame image according to the value of the degree of movement of each pixel of the motion probability image, and determining the mixing ratio so that the greater the degree of movement represented by the value of each pixel of the motion probability image, the greater the reaction ratio of the current frame image compared with the previous frame image.

[0021] In the working method of the radiation imaging device according to the present disclosure, the step of obtaining brightness information includes: averaging the pixel values ​​contained in at least a part of the first radiation image to obtain the brightness information, and the step of determining the first irradiation condition includes: determining the first irradiation condition so that when the brightness information is less than a predetermined first critical brightness information, the brightness information increases; and determining the first irradiation condition so that when the brightness information is greater than the predetermined first critical brightness information, the brightness information decreases.

[0022] In the working method of the radiation imaging device according to the present disclosure, the step of averaging the pixel values ​​contained in at least a part of the first radiation image to obtain brightness information includes: the step of acquiring the area where the subject appears in the first radiation image based on the subject area acquisition model; and the step of averaging the pixel values ​​contained in the area where the subject appears to obtain brightness information.

[0023] In the working method of the radiation imaging device according to the present disclosure, the step of determining the second irradiation condition includes: downsampling the second radiation image in patch units of a predetermined size to obtain a downsampled image; obtaining the minimum pixel value among the pixel values ​​contained in the downsampled image; and determining the second irradiation condition so that when the minimum pixel value is greater than the predetermined second critical brightness information, the minimum pixel value is the same as the second critical brightness information.

[0024] In the working method of the radiation imaging device according to the present disclosure, the step of determining the second irradiation condition so that the minimum pixel value is the same as the second critical brightness information includes: the step of determining a reduction ratio based on the minimum pixel value and the second critical brightness information; and determining the second irradiation condition so that the dose irradiated from the radiation irradiation part according to the first irradiation condition is subtracted from the dose according to the first irradiation condition multiplied by the value of the reduction ratio, and the reduction ratio is greater than 0 and less than a predetermined maximum reduction ratio.

[0025] In the working method of the radiation image shooting device according to the present disclosure, the step of obtaining movement information includes: when the time for obtaining at least one of the first radiation image and the second radiation image is less than a predetermined critical time, the step of determining that the movement information indicates that the shooting part of the subject is not fixed; and when the time for obtaining at least one of the first radiation image and the second radiation image is longer than the predetermined critical time, the step of determining that the movement information indicates that the shooting part of the subject is fixed.

[0026] Furthermore, a program for realizing the operating method of the radiation imaging apparatus as described above may be recorded in a computer-readable recording medium.

[0027] Effects of the Invention

[0028] The radiographic imaging device of the present disclosure can clearly fix the image brightness to solve the above-mentioned problems. In addition, when it is determined that the imaging part is fixed, the radiographic imaging device can use the optimal irradiation conditions that match the corresponding part to reduce the patient's radiation exposure.

[0029] The radiographic imaging device disclosed herein can minimize the radiation exposure of patients and users by acquiring low-dose radiographic images. In addition, the radiographic imaging device disclosed herein can help users make medical judgments by providing them with low-dose and high-definition images. In addition, the radiographic imaging device disclosed herein can quickly acquire low-dose radiographic images by minimizing image processing, thereby helping users to quickly perform medical operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a schematic diagram showing a mobile radiation imaging device according to an embodiment of the present disclosure.

[0031] Figure 2 : is a block diagram showing various configurations that may be included in a radiation imaging apparatus according to an embodiment of the present disclosure.

[0032] Figure 3 Detailed description is a flowchart showing an operating method of a radiation imaging device according to an embodiment of the present disclosure.

[0033] Figure 4 Detailed description is a flowchart showing an operating method of a radiation imaging device according to an embodiment of the present disclosure.

[0034] Figure 5 is a flowchart illustrating the operation of the radiation imaging apparatus according to one embodiment of the present disclosure.

[0035] Figure 6It may be a diagram for explaining downsampling according to one embodiment of the present disclosure.

[0036] Figure 7 is a flowchart for explaining a process for acquiring the second irradiation condition according to one embodiment of the present disclosure.

[0037] Figure 8 1 is a schematic diagram for explaining the operation of the radiation imaging device according to one embodiment of the present disclosure.

[0038] Fig. 9 is a flowchart illustrating the operation of the radiation imaging apparatus according to one embodiment of the present disclosure.

[0039] Fig.10 1 is a schematic diagram for explaining the operation of the radiation imaging device according to one embodiment of the present disclosure.

[0040] Fig.11 1 is a schematic diagram for explaining the operation of the radiation imaging device according to one embodiment of the present disclosure.

[0041] Fig.12 1 is a schematic diagram for explaining the operation of the radiation imaging device according to one embodiment of the present disclosure. DETAILED DESCRIPTION

[0042] By referring to the accompanying drawings and the embodiments described below, the advantages and features of the disclosed embodiments and the methods for implementing them can be made clear. However, the present disclosure is not limited to the embodiments disclosed below and can be implemented in various different forms. The embodiments are provided only to complete the present disclosure and fully inform the ordinary technicians in the technical field to which the present disclosure belongs of the scope of the invention.

[0043] The terms used in this specification are briefly explained, and the disclosed embodiments are described in detail.

[0044] The terms used in this specification are selected as common terms that are currently widely used as much as possible while considering the functions in the present disclosure, but this may vary depending on the intentions of technicians engaged in related fields or precedents, the emergence of new technologies, etc. In addition, in certain cases, there are terms that the applicant arbitrarily selects, in which case their meanings will be described in detail in the description section of the corresponding invention. Therefore, the terms used in this disclosure are not simple term names, but should be defined based on the meanings of the terms and the full content of this disclosure.

[0045] Unless the context clearly specifies the singular, a singular expression in this specification includes a plural expression. In addition, unless the context clearly specifies the plural, a plural expression includes a singular expression.

[0046] Throughout the specification, when it is stated that a part “includes” a certain component, unless otherwise specifically described to the contrary, it means that other components may be further included, rather than being excluded.

[0047] In addition, the term "unit" used in the specification refers to a software or hardware component, and the "unit" performs certain functions. However, the "unit" is not limited to the meaning of software or hardware. The "unit" can be configured to be in an addressable storage medium, or it can be configured to play one or more processors. Therefore, as an example, the "unit" includes components such as software components, object-oriented software components, class components and task components, processes, functions, properties, programs, subroutines, fragments of program code, drivers, firmware, microcodes, circuits, data, databases, data structures, tables, arrays and variables. The functions provided in the components and "units" can be combined into smaller components and "units", or further separated into additional components and "units".

[0048] According to one embodiment of the present disclosure, the "unit" can be implemented as a processor and a memory. The term "processor" should be interpreted broadly, including a general-purpose processor, a central processing unit (CPU), a microprocessor, a digital signal processor (DSP), a controller, a microcontroller, a state machine, etc. In some environments, the "processor" may also refer to a combination of processing devices such as a combination of a digital signal processor (DSP) and a microprocessor, a combination of multiple microprocessors, a combination of more than one microprocessor combined with a digital signal processor (DSP) core, or a combination of any other configurations.

[0049] The term "memory" should be interpreted broadly to include any electronic component that can store electronic information. The term memory may also refer to various types of processor-readable media such as random access memory (RAM), read-only memory (ROM), non-volatile random access memory (NVRAM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electronically erasable programmable PROM (EEPROM), flash memory, magnetic or optical data storage devices, registers, etc. A memory is said to be in electronic communication with a processor if the processor is able to read information from and / or record information in the memory. Memory that is integrated into a processor is in electronic communication with the processor.

[0050] Hereinafter, the embodiments are described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present disclosure. In addition, in order to clearly illustrate the present disclosure, parts not related to the description are omitted in the accompanying drawings.

[0051] Figure 1is a schematic diagram showing a mobile radiation imaging device according to an embodiment of the present disclosure.

[0052] Figure 1 2 shows an example of a C-arm-shaped radiation imaging device 100 according to an embodiment of the present disclosure. However, the radiation imaging device 100 of the present disclosure is not limited thereto, and may have various forms.

[0053] The radiation imaging device according to the embodiment of the present disclosure may be formed, for example, by Figure 1 The C-arm configuration shown in the figure can also obtain a video. The radiographic imaging device can use radiation such as X-rays to image a region of interest of the object S as an imaging target.

[0054] Reference Figure 1 The radiation imaging device 100 may include a radiation irradiation unit 111 for outputting radiation, such as X-rays, and an image acquisition unit 112 for receiving radiation transmitted through the object S and acquiring image data. The radiation irradiation unit 111 and the image acquisition unit 112 may be supported at both ends of the C-arm 110. For example, the radiation imaging device may be applicable to a mobile C-arm X-ray imaging device, an interventional X-ray device, an interventional angiography C-arm X-ray device, and the like.

[0055] The support structure supports the radiation irradiation unit 111 and the image acquisition unit 112 and is configured to be able to change the spatial position and rotational position of the radiation irradiation unit 111 and the image acquisition unit 112 to change the imaging position and angle of the object S. For example, the support structure may include a support body 150, a lifting column 130 fastened to the support body 150 so as to be movable in the up-down direction D1, and a forward-retracting arm 120 fastened to the lifting column 130 so as to be movable in the up-down direction together with the lifting column 130 and to be relatively movable in the horizontal direction D2 relative to the lifting column 130.

[0056] The C-arm 110 is fastened to the forward-retractable arm 120 in such a manner that it can rotate relative to the forward-retractable arm 120 in at least one rotation direction, and the radiation irradiation unit 111 and the image acquisition unit 112 are fastened to both side ends of the C-arm 110, respectively. At this time, the C-arm 110 can be fastened to the forward-retractable arm 120 in such a manner that the C-arm 110 can move up and down in the vertical direction and move forward and backward in the horizontal direction together with the forward-retractable arm 120, and can rotate relative to the forward-retractable arm 120 in at least one rotation direction, for example, in at least one rotation direction of the orbital rotation direction R1 and the axial rotation direction R2 centered on the direction parallel to the horizontal movement direction of the forward-retractable arm 120. Although not shown in the figure, the support structure may include a brake, for example, a motor for the vertical movement of the lifting column 130, the horizontal movement of the forward-retractable arm 120, and the rotation of the C-arm 110. The elements of the C-arm 110 used to support and drive the support member for supporting the radiation irradiation unit 111 and the image acquisition unit 112, that is, the forward and backward arm 120, the lifting column 130 and the actuator disposed therein can be said to be the driving elements for driving the C-arm 110, and their combination can be said to be the driving unit for driving the C-arm 110. In addition, it can also be configured to make the C-arm 110 perform a panning rotation by the lateral rotation of the forward and backward arm 120. The shape of the support member is not limited to the "C" shape. In other embodiments of the present disclosure, "U"-shaped, "G"-shaped, "O"-shaped, etc. arms can also be used instead of the "C" shape as the support member.

[0057] The display unit 140 is configured to be able to display at least one of real-time position information, image data, reference position information, and radiation output information. The display unit 140 can be any device that can display information and images, such as a printer, a cathode ray tube (CRT) display, a liquid crystal display (LCD), a plasma display (PDP), an organic light emitting diode (OLED) display, a field emission display (FED), a light emitting diode (LED) display, a digital light processing (DLP) display, a primary flight display (PFD), a three-dimensional (3D) display, a transparent display, etc. In addition, the display unit 140 can also be implemented in a form that can display and input information, such as a touch screen that can receive input from a user.

[0058] Figure 2 : is a block diagram showing various configurations that may be included in a radiation imaging apparatus according to an embodiment of the present disclosure.

[0059] Reference Figure 2The radiation imaging device 100 may include at least one of a control unit 200 , a sensor unit 210 , a communication unit 220 , a memory 230 , an output unit 240 , and an input unit 250 . Figure 1 The appearance of the radiation imaging device 100 is briefly shown. Figure 2 A block diagram showing a functional division of the radiation imaging apparatus 100 is shown. Figure 2 At least one of the control unit 200, the sensor unit 210, the communication unit 220, the memory 230, the output unit 240, and the input unit 250 may be included in the Figure 1 The radiation irradiation part 111, the image acquisition part 112, the support body 150, the lifting column 130 and the forward and backward arm 120 may be inside or may be combined to the outside of at least one of the radiation irradiation part 111, the image acquisition part 112, the support body 150, the lifting column 130 and the forward and backward arm 120.

[0060] According to an embodiment of the present disclosure, the radiographic imaging device 100 may include a control unit 200. The control unit 200 may be implemented in the form of an information processing device such as one or more computers that can perform information processing and calculations. For example, the computer may include a control unit such as a central processing unit (CPU), a memory unit such as a read only memory (ROM) or a random access memory (RAM), and an image control unit such as a graphics processing unit (GPU). The computer may also include a communication unit such as a network card, and an input / output unit such as a keyboard, a display, or a touch screen. As is known, components of a computer like this can be connected via a bus and can be operated and controlled by executing a program stored in a memory unit.

[0061] The radiation imaging device 100, which can be realized in the form of a computer capable of performing information processing, can be installed in a computer such as Figure 1 In the radiation imaging device 100 shown, an image processing function is performed. In this case, as a part of the radiation imaging device, a captured image can be received and processed, and the processed image can be displayed on the display unit 140 of the radiation imaging device.

[0062] The radiation imaging device 100 may include a sensor unit 210. The sensor unit 210 may obtain various information by using at least one sensor. The sensor unit 210 may be configured as a sensor using a measuring unit such as pressure, potential, and optics. For example, the sensor unit 210 may include at least one of a distance measuring sensor or an encoder. In addition, the sensor may include a pressure sensor, an infrared sensor, a light emitting diode (LED) sensor, a touch sensor, etc. However, it is not limited thereto. The sensor unit may also be included in at least one of the radiation irradiation unit 111, the image acquisition unit 112, the support body 150, the lifting column 130, the forward and backward arm 120, and the C-arm 110.

[0063] In addition, the radiation imaging device 100 may include a communication unit 220. The communication unit 220 may be a configuration for the radiation imaging device 100 to perform wired / wireless communication with an internal module or an external device. The external device may include an external server, a user terminal. The user terminal may include a personal computer (PC), a smart phone, a tablet computer, or a wearable device. The communication unit 220 may include a wired / wireless communication module for network connection. As a wireless communication technology, for example, a wireless local area network (Wireless LAN, WLAN) (Wireless Compatibility Certification (Wi-Fi)), wireless broadband (Wireless broadband, Wibro), World Interoperability for Microwave Access (World Interoperability for Microwave Access, Wimax), High Speed ​​Downlink Packet Access (High Speed ​​Downlink Packet Access, HSDPA), etc. may be used. As a wired communication technology, for example, a digital subscriber line (Digital Subscriber Line, XDSL), fiber to the home (Fibers to the home, FTTH), power line communication (Power Line Communication, PLC), etc. may be used. In addition, the network connection unit includes a short-distance communication module, so that data can be sent and received with any device / terminal located at a short distance. For example, as short range communication technology, Bluetooth, Radio Frequency Identification (RFID), infrared Data Association (IrDA), Ultra-Wideband (UWB), ZigBee, etc. can be used, but are not limited to these.

[0064] The radiation imaging device 100 may include a memory 230. The control unit 200 may execute commands stored in the memory. The control unit 200 and the memory 230 may be independent hardware, but are not limited thereto, and the control unit 200 may also include the memory 230. That is, the memory 230 may be included in the control unit 200, or may be located outside the control unit 200. The memory 230 may store various information related to the radiation imaging device 100. For example, the memory 230 may include information related to the working method of the radiation irradiation unit 111, and may include captured images and user authentication information, but are not limited thereto.

[0065] The memory 230 may be implemented by a non-volatile storage medium capable of continuously storing any data. For example, the memory 230 may include not only a magnetic disk, an optical disk, and a magneto-optical storage device, but may also include a storage device based on flash memory and / or a battery backup memory, but is not limited thereto. The memory 230 is a main storage device such as a random access memory (RAM) such as a dynamic random access memory (DRAM) and a static random access memory (SRAM), which is directly accessible to the processor, and may mean a volatile storage device in which the stored information is instantly deleted after the power is turned off, but is not limited thereto. These memories 230 may be operated by the control unit 200. In addition, the control unit 200 may also execute the commands contained in the memory 230.

[0066] Furthermore, the radiation imaging apparatus 100 may further include an operation section that provides an interface for operation of the radiation imaging apparatus 100. The operation section may include an output section 240 and an input section 250.

[0067] The output unit 240 may output information related to the shooting such as the irradiation of X-rays or sound and images that can confirm the state of the subject under the control of the control unit 200. The output unit 240 may include the display unit 140. The output unit 240 may include a speaker or a display. The output unit 240 may output the medical image generated by the control unit 200. The output unit 240 may output information required by the user to operate the radiation imaging device 100, such as a user interface (UI), user information, or subject information. As examples of the output unit 240, a speaker, a printer, a cathode ray tube (CRT) display, a liquid crystal display (LCD), a plasma display (PDP), an organic light emitting diode (OLED) display, a field emission display (FED), a light emitting diode (LED) display, a VFD display, a digital light processing (DLP) display, an FPD display, a three-dimensional (3D) display, a transparent display, etc. may be included, and various output devices may be included within the scope that is obvious to ordinary technicians in the technical field to which the present disclosure belongs.

[0068] The radiation imaging apparatus 100 may be connected to the workstation via wired / wireless communication. The workstation may also exist in a space physically separated from the radiation imaging apparatus 100 .

[0069] The workstation may include a storage server. The storage server may store medical images, subject information, user (medical personnel) information, etc. The workstation may include an evaluation device. The evaluation device may receive medical images from the storage server based on a user's command to diagnose the medical images. The workstation and the radiographic imaging device 100 may transmit, store, process, and output data according to the Digital Imaging and Communications in Medicine (DICOM) standard. In addition, the workstation may include a Picture Archiving and Communication System (PACS).

[0070] The workstation may include an output unit, an input unit, and a control unit. The output unit and the input unit provide a user with an interface for operating the workstation and the radiation imaging apparatus 100. The control unit of the workstation may control the workstation and the radiation imaging apparatus 100.

[0071] The radiographic imaging device 100 may be controlled through the workstation, or through the control unit 200 included in the radiographic imaging device 100. Therefore, the user may control the radiographic imaging device 100 through the workstation, or through the operation unit and the control unit 200 included in the radiographic imaging device 100. That is, the user may remotely control the radiographic imaging device 100 through the workstation, or directly control the radiographic imaging device 100.

[0072] The control unit of the workstation and the control unit 200 of the radiographic imaging apparatus 100 may be separate, but are not limited thereto. The control unit of the workstation and the control unit 200 of the radiographic imaging apparatus 100 may be implemented as an integrated control unit, or the integrated control unit may be included in only one of the workstation and the radiographic imaging apparatus 100. Hereinafter, the control unit 200 may refer to the control unit of the workstation and / or the control unit of the radiographic imaging apparatus 100.

[0073] The output unit and input unit of the workstation and the output unit 240 and input unit 250 of the radiographic imaging apparatus 100 may respectively provide the user with an interface for operating the radiographic imaging apparatus 100. The workstation and the radiographic imaging apparatus 100 may include an output unit and an input unit, respectively, but are not limited thereto. The output unit or the input unit may also be implemented in only one of the workstation and the radiographic imaging apparatus 100.

[0074] Hereinafter, the input unit 250 refers to an input unit of the workstation and / or an input unit of the radiation imaging apparatus 100 , and the output unit 240 refers to an output unit of the workstation and / or an output unit of the radiation imaging apparatus 100 .

[0075] The input unit 250 may receive commands for operating the radiation imaging apparatus 100 and input of various information related to X-ray imaging from a user. The control unit 200 may control or operate the radiation imaging apparatus 100 based on the information input into the input unit 250. The input unit 250 may include a joystick, a keyboard, a mouse, a touch screen, a shooting button, an unlocking button, a voice recognizer, a fingerprint recognizer, an iris recognizer, and a human body movement recognizer, etc., and may include other input devices that are obvious to a person of ordinary skill in the art to which the present disclosure belongs.

[0076] The user may input a command for irradiating X-rays through the input unit 250, and a switch for inputting the command may be provided in the input unit 250. The switch must be pressed at least once to input an irradiation command for irradiating X-rays.

[0077] For example, when the user presses the switch, the switch may input a preparation command indicating preheating of X-ray irradiation, and when the user further presses the switch in this state, it may have a structure for inputting a substantial irradiation command for irradiating X-rays. As described above, when the user operates the switch, the control unit 200 generates a signal corresponding to the command input by the switch operation, that is, a preparation signal, and sends it to a high voltage generating unit for generating a high voltage for generating X-rays. The high voltage generating unit may be included in the radiation irradiation unit 111.

[0078] The high voltage generating unit included in the radiation irradiation unit 111 receives the preparation signal sent from the control unit 200 and starts preheating. When the preheating is completed, a preparation completion signal is sent to the control unit 200. In addition, in order to detect X-rays, the image acquisition unit 112 also needs to prepare for X-ray detection. The control unit 200 sends a preparation signal to the image acquisition unit 112 so that the image acquisition unit 112 is ready to detect X-rays that pass through the irradiated object while preheating the high voltage generating unit. When the image acquisition unit 112 receives the preparation signal, it prepares to detect X-rays, and when the detection preparation is completed, it sends a detection preparation completion signal to the control unit 200.

[0079] When the preheating of the high voltage generating unit included in the radiation irradiation unit 111 is completed and the X-ray detection preparation of the image acquisition unit 112 is completed, the control unit 200 sends an irradiation signal to the high voltage generating unit, the high voltage generating unit generates a high voltage and applies it to the X-ray source included in the radiation irradiation unit 111, and the X-ray source is irradiated with X-rays. The X-ray source can change the irradiation dose of X-rays according to at least one of the tube voltage, the tube current, and the irradiation time of the X-ray pulse controlled by the control unit 200.

[0080] When the control unit 300 sends the irradiation signal, it can send a sound or light output signal to the output unit 240 so that the subject or the user knows that the X-ray irradiation is being performed, and the output unit 240 outputs a specified sound or light. In addition to the X-ray irradiation, the output unit 240 can also output a sound or light indicating other information related to the shooting. The output unit 240 may be included in the operation unit, but is not limited thereto, and the output unit 240 or a part of the output unit 240 may be located at a position different from the position where the operation unit is located. For example, it may also be located on the wall of the photography room where the X-ray of the subject is taken.

[0081] The control unit 300 controls the position, imaging timing, imaging conditions, etc. of the radiation irradiation unit 111 and the image acquisition unit 112 according to the imaging conditions set by the user.

[0082] Specifically, the control unit 200 controls the high voltage generation unit and the image acquisition unit 112 according to the command input through the input unit 250 to control the irradiation timing of X-rays, the intensity of X-rays, and the irradiation area of ​​X-rays, etc. In addition, the control unit 200 adjusts the position of the image acquisition unit 112 according to the prescribed shooting conditions and controls the operation timing of the image acquisition unit 112.

[0083] In addition, the control unit 200 generates a medical image of the subject using the image data received through the image acquisition unit 112. Specifically, the control unit 200 can generate a medical image of the subject by removing noise from the image data by receiving the image data from the image acquisition unit 112, and adjusting the dynamic range and interleaving.

[0084] The workstation may further include a communication unit (not shown) that can be connected to a server, a medical device, a portable terminal, etc. through a network. The workstation may be one of the external devices.

[0085] The control unit 200 according to an embodiment of the present disclosure is further described in detail below. The control unit 200 may include at least one hardware module or at least one software module. The module may refer to at least one of hardware or software divided into functional units. More specifically, the control unit 200 of the radiation imaging device 100 may include at least one of an image output unit 201, an image brightness information extraction unit 202, a first irradiation condition calculation unit 203, an irradiation control unit 204, a second irradiation condition calculation unit 205, and a dose reduction unit 206.

[0086] The image output unit 201 may be configured to output a first radiographic image included in a continuous radiographic image obtained by radiographically photographing the subject. The image output unit 201 may be configured to be included in the control unit 200, and to process the data acquired from the image acquisition unit 112 to generate a continuous radiographic image. However, the image output unit 201 may also be configured to be included in the output unit 240 to display the image generated by the control unit 200. The continuous radiographic image may be referred to as, for example, at least one of an X-ray image, an X-ray moving image, or a fluoroscopic image (FLUOROSCOPY).

[0087] The radiation imaging device 100 can acquire continuous radiation images. That is, the radiation imaging device 100 can acquire videos. The continuous radiation images may include a plurality of still radiation images. In the present disclosure, still radiation images may be referred to as frame images.

[0088] The first radiographic image may be included in the continuous radiographic images. The first radiographic image may include at least one frame image. The first radiographic image may also be an image acquired by performing image processing on at least one frame image. The radiographic image shooting device 100 may store predetermined irradiation conditions. The predetermined irradiation conditions may include at least one of a predetermined tube voltage, a predetermined tube current, and a predetermined irradiation time of an X-ray pulse. The predetermined irradiation conditions may be stored by the radiographic image shooting device 100 and may be automatically selected during shooting. In addition, the predetermined irradiation conditions may also be based on a user's selection. The radiographic image shooting device 100 may control the radiation irradiation unit 111 based on the predetermined irradiation conditions to irradiate the radiation to the subject, and the image acquisition unit 112 may acquire the first radiographic image.

[0089] The first radiographic image may include an image of a subject. In order to make the subject appear clearly in the radiographic image, it may be necessary to change the irradiation conditions according to the subject information. However, since the first radiographic image utilizes predetermined irradiation conditions, it is possible that the image is not optimized according to the subject information. The subject information may include at least one of the thickness of the subject, the type of the subject, the location of the subject, the material of the subject, and the density of the subject. Therefore, the radiographic image shooting device 100 further includes the following configuration so as to be able to determine the optimized irradiation conditions for the subject while achieving a low dose.

[0090] The image brightness information extraction unit 202 may include a step of acquiring brightness information from the first radiation image. The image brightness information extraction unit 202 may be included in the control unit 200 .

[0091] The region of interest is automatically extracted without user intervention. The image brightness information extraction unit 202 can obtain brightness information based on at least one of the statistical values ​​of the maximum value, minimum value, average value, median value, and standard deviation of the pixels and at least one of the distribution graph (ex. histogram) based on the pixel value, the feature points extracted from the image, and the positions of the feature points. The process of obtaining brightness information by the image brightness information extraction unit 202 will be described later.

[0092] The first irradiation condition calculation unit 203 may determine the first irradiation condition based on the brightness information. The first irradiation condition calculation unit 203 may also be included in the control unit 200. The first irradiation condition calculation unit 203 may be configured to control the brightness information of the first radiographic image to be similar to the predetermined brightness information. The first irradiation condition may be information for controlling the radiation irradiation unit 111. The first irradiation condition may include at least one of a first tube voltage, a first tube current, and an irradiation time of a first X-ray pulse.

[0093] The first irradiation condition calculation unit 203 can determine at least one value of the first tube voltage, the first tube current, and the irradiation time of the first X-ray pulse of the radiation irradiation unit 111 based on the brightness information of the first radiographic image. For example, the greater the first tube voltage and the first tube current, the greater the irradiation dose of the X-ray. Since the irradiation time of the first X-ray pulse is a value proportional to the time when the X-ray source emits X-rays, the longer the irradiation time of the first X-ray pulse, the greater the irradiation dose of the X-ray. In addition, as the irradiation dose increases, the brightness information of the first radiographic image can become brighter. However, it is not limited to this, as the irradiation dose increases, the brightness information of the first radiographic image will become darker. The first irradiation condition calculation unit 203 can determine the first irradiation condition, which includes at least one of the first tube voltage, the first tube current, and the irradiation time of the first X-ray pulse for making the brightness information of the first radiographic image similar to the predetermined brightness information. The first irradiation condition may be different from the predetermined irradiation condition. However, in certain cases, the first irradiation condition may also be the same as the predetermined irradiation condition.

[0094] The irradiation control section 204 may control the dose of radiation based on the first irradiation condition. The irradiation control section 204 may be included in the control section 200. The irradiation control section 204 may control the operation of the radiation irradiation section 111 based on the first irradiation condition including at least one of the first tube voltage, the first tube current, and the irradiation time of the first X-ray pulse acquired from the first irradiation condition calculation section 203.

[0095] The radiation irradiation unit 111 may irradiate the radiation to the object based on the first irradiation condition. The image acquisition unit 112 may acquire a second radiation image based on the radiation based on at least one of the determined tube voltage, tube current, and irradiation time of the X-ray pulse. The second radiation image may be a radiation image generated after the first radiation image. The second radiation image may be included in a continuous radiation image. The second radiation image may include at least one frame image in a video.

[0096] In addition, if the first radiographic image is an image based on a predetermined irradiation condition, the second radiographic image may be an image based on the first irradiation condition. The object appearing in the second radiographic image is similar to the predetermined brightness information, so the object can be clearly displayed in the second radiographic image. Therefore, the user can easily diagnose the patient based on the second radiographic image. However, the second radiographic image may not be based on the minimum dose. While utilizing the minimum dose, the radiographic image shooting device 100 may further perform the following process in order to maintain image quality.

[0097] The second irradiation condition calculation unit 205 may be included in the control unit 200. When the imaging part of the object is fixed, the second irradiation condition calculation unit 205 may determine the second irradiation condition based on the second radiographic image generated based on the first irradiation condition. The second irradiation condition may be an irradiation condition that achieves the lowest dose while maintaining image quality. The second irradiation condition may be different from the first irradiation condition. However, in certain cases, the second irradiation condition may also be the same as the first irradiation condition. The second irradiation condition may include at least one of a second tube voltage, a second tube current, and an irradiation time of a second X-ray pulse. The second irradiation condition may be a minimum irradiation condition that keeps the image quality of the fixed imaging part similar to the image quality according to the first irradiation condition.

[0098] The value of the radiation dose based on the first irradiation condition minus the radiation dose based on the second irradiation condition may be less than or equal to 70% of the dose based on the first irradiation condition. That is, the radiation dose based on the second irradiation condition may be equal to 30% of the radiation dose based on the first irradiation condition, or more than 30%. As described above, the radiation dose based on the second irradiation condition is less than the radiation dose based on the first irradiation condition, so the patient or user may be exposed to less radiation. However, the radiation imaging device 100 of the present disclosure provides images of the same quality, thereby improving the convenience of the user while maintaining the health of the patient and the user.

[0099] The dose reduction unit 206 may reduce or maintain the dose of radiation based on the second irradiation condition. The dose reduction unit 206 may be included in the control unit 200. The dose reduction unit 206 may be independent of the irradiation control unit 204. However, the dose reduction unit 206 may have the same configuration as the irradiation control unit 204.

[0100] The dose reduction unit 206 may control the dose of radiation based on the second irradiation condition. The dose reduction unit 206 may control the operation of the radiation irradiation unit 111 based on the second irradiation condition including at least one of the second tube voltage, the second tube current, and the irradiation time of the second X-ray pulse acquired from the second irradiation condition calculation unit 205.

[0101] The radiation irradiation unit 111 may irradiate the radiation to the object based on the second irradiation condition. The image acquisition unit 112 may acquire a third radiation image based on the radiation according to at least one of the determined second tube voltage, the second tube current, and the irradiation time of the second X-ray pulse. The third radiation image may be a radiation image generated after the second radiation image. The third radiation image may be included in the continuous radiation image. The third radiation image may include at least one frame image in the video.

[0102] Furthermore, if the second radiographic image is an image based on the first irradiation condition, the third radiographic image may be an image based on the second irradiation condition. The third radiographic image may maintain the same quality as the second radiographic image. That is, the clarity and noise of the subject appearing in the third radiographic image are substantially the same as the clarity and noise of the subject appearing in the second radiographic image. However, the dose of radiation irradiated to the subject in order to obtain the third radiographic image is less than or equal to the dose of radiation irradiated to the subject in order to obtain the second radiographic image.

[0103] When the dose is reduced due to the dose reduction unit 206, the first irradiation condition calculation unit 203 may be disabled. That is, the radiation image capturing device 100 may not obtain the first irradiation condition through the first irradiation condition calculation unit 203. The radiation image capturing device 100 may not match the subject of the continuous radiation images with the predetermined brightness information. The radiation image capturing device 100 may capture continuous radiation images based on the second irradiation condition. The radiation image capturing device 100 may capture a third radiation image using the lowest dose based on the second irradiation condition. The condition for acquiring the second irradiation condition is that the subject is fixed, and when the subject is not moving, a high-quality radiation image can be acquired even with the lowest dose. Therefore, the side effects caused by radiation to the user and the patient can be reduced.

[0104] In addition, the radiation imaging device 100 may perform cumulative averaging of pixel values ​​in the current frame image included in the third radiation image and in the previous frame image included in the third radiation image output by the dose reduced by the dose reducing unit 206 to generate an improved current frame image. In the present disclosure, the pixel value may be a pixel value of a pixel included in the display, or a pixel value indicating the degree to which one of the plurality of pixels included in the image acquisition unit 112 is excited by radiation. The pixel value may have a value of 10 bits or more and 16 bits or less.

[0105] As described above, the third radiographic image may include at least one frame image. The third radiographic image may include a current frame image 830 and a previous frame image 820. The current frame image may be a frame most recently acquired by the image acquisition unit 112. The previous frame image 820 may be at least one frame image acquired before the current frame image. The previous frame image 820 may include a previous frame image 82 and an n-2 frame image 821, etc. The previous frame image may be a frame image previous to the current frame image.

[0106] The radiographic imaging device 100 can generate an improved current frame image by accumulating and averaging the current frame image and a predetermined number of previous frame images. The predetermined number may be greater than or equal to 1. The predetermined number may refer to the number of frames. The radiographic imaging device 100 can accumulatively average the pixel value of a pixel of the current frame image and the pixel value of the previous frame image at a position corresponding to the pixel of the current frame image. The radiographic imaging device 100 can accumulate the average pixel value between the corresponding pixels in the current frame image and the previous frame image, thereby obtaining the pixel value contained in the improved current frame image. The corresponding pixels refer to the positions (coordinate values) of the pixels in the current frame image and the positions (coordinate values) of the pixels in the previous frame image being the same as each other. The radiographic imaging device 100 can generate an improved current frame image by obtaining the cumulative average value of all pixels contained in the current frame image and all pixels contained in the previous frame image.

[0107] As described above, since the object does not move, the change in the pixel value of the pixel at the same position in the continuous frame image may be small. Therefore, when the cumulative average is performed in the manner described above to obtain the improved current frame image, the influence of noise can be minimized. This is because noise is generated by a large change in the pixel value of a pixel.

[0108] The radiation imaging device 100 may further include an image post-processing unit 207, which may post-process the third radiation image outputted by the dose reduced by the dose reducing unit 206. The image post-processing unit 207 may adjust at least one of brightness information and contrast information of at least one of the first radiation image, the second radiation image, and the third radiation image so as to maintain a specified brightness based on predetermined brightness information. Unlike the first irradiation condition calculation unit 203, the image post-processing unit 207 does not determine the irradiation conditions for controlling the radiation irradiation unit 111, but processes the radiation image by software.

[0109] The image post-processing unit 207 of the radiation imaging device 100 may adjust the pixel values ​​of the third radiation image so that the brightness information of the third radiation image is similar to the predetermined brightness information. The radiation imaging device 100 may adjust all pixel values ​​included in the third radiation image using the same ratio or the same subtraction value, and the brightness information of the third radiation image may be similar to the predetermined brightness information. The predetermined brightness information may be brightness information stored in a memory.

[0110] However, the predetermined brightness information may be a value measured by the image brightness information extraction unit 202. For example, the radiation imaging device 100 may measure at least one brightness information of the first to second radiation images using the image brightness information extraction unit 202. The radiation imaging device 100 may measure the brightness information of the second radiation image. The image post-processing unit 207 of the radiation imaging device 100 may adjust the pixel values ​​of the third radiation image so that the brightness information of the third radiation image is similar to the brightness information of the second radiation image. The image post-processing unit 207 may adjust at least one of the brightness information and the contrast information of the third radiation image similarly to at least one of the brightness information and the contrast information of the second radiation image. The radiation imaging device 100 may adjust all pixel values ​​contained in the third radiation image using the same ratio or the same subtraction value, and the brightness information of the third radiation image may be similar to the brightness information of the second radiation image.

[0111] For reference, similarity in the present disclosure may mean that the difference between two pieces of information is less than or equal to a predetermined range. For example, the brightness information of the second radiographic image is similar to the brightness information of the third radiographic image, which may mean that the absolute value of the difference between the brightness information of the second radiographic image and the brightness information of the third radiographic image is less than or equal to a predetermined range. The predetermined range may be a value greater than or equal to 0.

[0112] The following describes in detail the operating method of the radiation imaging device.

[0113] Figure 3 Detailed description is a flowchart showing an operating method of a radiation imaging device according to an embodiment of the present disclosure.

[0114] As described above, the radiation imaging device 100 may include the radiation irradiation unit 111 for irradiating radiation to the subject. In addition, the radiation imaging device 100 may include the image acquisition unit 112 for receiving the radiation irradiated from the radiation irradiation unit 111 and passing through the subject to generate continuous radiation images.

[0115] The radiation imaging device 100 may include a control section 200 that controls the radiation irradiation section and the image acquisition section 112. The control section 200 may perform the following operations.

[0116] The control unit 200 may execute step (310), i.e., acquire a first radiographic image. The image output unit 201 may output the first radiographic image. The first radiographic image may be included in a continuous radiographic image. The first radiographic image may include at least one frame image. The first radiographic image may be an image acquired by performing image processing on at least one frame image. The radiographic image shooting device 100 may store predetermined irradiation conditions. The predetermined irradiation conditions may include at least one of a predetermined tube voltage, a predetermined tube current, and a predetermined irradiation time of an X-ray pulse. The radiographic image shooting device 100 may control the radiation irradiation unit 111 based on the predetermined irradiation conditions to irradiate the radiation to the subject. The image acquisition unit 112 may acquire the first radiographic image.

[0117] The control unit 200 may execute step ( 320 ), that is, acquire brightness information based on the first radiographic image included in the continuous radiographic images. The brightness information may be acquired by the image brightness information extraction unit 202 .

[0118] The control unit 200 may perform step (330), that is, determine the first illumination condition based on the brightness information according to the first algorithm. As described above, the first illumination condition may be determined by the first illumination condition calculation unit 203.

[0119] Reference Figure 4 , further describing step (320) and step (330) in detail.

[0120] Figure 4 Detailed description is a flowchart showing an operating method of a radiation imaging device according to an embodiment of the present disclosure.

[0121] The step of acquiring brightness information (320) may include the following steps.

[0122] The control unit 200 may perform step (410), i.e., average the pixel values ​​included in at least a portion of the first radiographic image to obtain brightness information. In order to obtain brightness information by averaging the pixel values ​​included in at least a portion of the first radiographic image, the control unit 200 may perform step (411), i.e., acquire the region where the subject appears in the first radiographic image based on the subject region acquisition model. The control unit 200 may determine the region where the subject appears in the first radiographic image based on a predetermined algorithm. The predetermined algorithm may be a machine learning model and a rule-based model. The control unit 200 may determine the region where the subject appears based on the information of the subject and the first radiographic image. The information of the subject may include at least one of the thickness of the subject, the type of the subject, the location of the subject, the material of the subject, and the density of the subject. The predetermined algorithm may be selected based on the information of the subject. The control unit 200 may determine the region where the subject appears in the first radiographic image based on the selected predetermined algorithm. The region where the subject appears may be a partial region of the first radiographic image. The region where the subject appears may mean an inner region of the outline of the subject appearing in the first radiation image.

[0123] The control unit 200 may perform step (412), that is, obtain brightness information by averaging the pixel values ​​included in the area where the object appears. However, the control unit 200 may obtain at least one of the minimum value, average value, and median value of the pixel values ​​of the pixels in the area where the object appears as the brightness information. However, the control unit 200 may obtain at least one of the minimum value, average value, and median value of the pixel values ​​of all pixels of the first radiographic image as the brightness information.

[0124] To perform the step (330) of determining the first irradiation condition, the control part 200 may perform the following process.

[0125] The control unit 200 may perform step (420), i.e., determine the first irradiation condition so that when the brightness information is less than the predetermined first critical brightness information, the brightness information increases. In addition, the control unit 200 may perform step (440), i.e., determine the first irradiation condition so that when the brightness information is greater than the predetermined first critical brightness information, the brightness information decreases. In addition, the control unit 200 may perform step (430), i.e., when the brightness information is the same as the predetermined first critical brightness information, determine the first irradiation condition as the predetermined irradiation condition. The predetermined irradiation condition may be an irradiation condition used to obtain the first radiographic image.

[0126] As described above, the first irradiation condition may include at least one of the first tube voltage, the first tube current, and the irradiation time of the first X-ray pulse. The first irradiation condition calculation unit 203 may determine at least one value of the first tube voltage, the first tube current, and the irradiation time of the first X-ray pulse of the radiation irradiation unit 111 based on the brightness information of the first radiographic image. For example, the greater the first tube voltage and the first tube current, the greater the irradiation dose of the X-ray. The irradiation time of the first X-ray pulse is a value proportional to the time for the X-ray source to emit X-rays, so the longer the irradiation time of the first X-ray pulse, the greater the irradiation dose of the X-ray may be. At least one of the first tube voltage, the first tube current, and the irradiation time of the first X-ray pulse may have a linear relationship with the irradiation dose. However, not limited to this, at least one of the first tube voltage, the first tube current, and the irradiation time of the first X-ray pulse may have a nonlinear relationship with the irradiation dose.

[0127] The control unit 200 may modify at least one of a predetermined tube voltage, a predetermined tube current, and an irradiation time of a predetermined X-ray pulse included in the predetermined irradiation condition based on at least one of a predetermined first irradiation condition function and a first irradiation condition table to determine at least one of a first tube voltage, a first tube current, and an irradiation time of a first X-ray pulse included in the first irradiation condition. The first irradiation condition function or the first irradiation condition table may be a function or a table for determining the first irradiation condition according to the predetermined irradiation condition and the brightness information of the first radiographic image.

[0128] According to one embodiment of the present disclosure, as the irradiation dose increases, the brightness information of the first radiation image may become brighter. At this time, when the brightness information is less than the predetermined first critical brightness information, the first irradiation condition may be greater than the predetermined irradiation condition. That is, when the brightness information is less than the predetermined first critical brightness information, at least one of the first tube voltage, the first tube current, and the irradiation time of the first X-ray pulse contained in the first irradiation condition may be greater than at least one of the predetermined tube voltage, the predetermined tube current, and the irradiation time of the predetermined X-ray pulse contained in the predetermined irradiation condition. In addition, when the brightness information is greater than the predetermined first critical brightness information, the first irradiation condition may be less than the predetermined irradiation condition. That is, when the brightness information is greater than the predetermined first critical brightness information, at least one of the first tube voltage, the first tube current, and the irradiation time of the first X-ray pulse contained in the first irradiation condition may be less than at least one of the predetermined tube voltage, the predetermined tube current, and the irradiation time of the predetermined X-ray pulse contained in the predetermined irradiation condition. In addition, when the brightness information is the same as the predetermined first critical brightness information, the first irradiation condition may be the same as the predetermined irradiation condition. That is, when the brightness information is the same as the predetermined first critical brightness information, at least one of the first tube voltage, the first tube current, and the irradiation time of the first X-ray pulse included in the first irradiation condition may be the same as at least one of the predetermined tube voltage, the predetermined tube current, and the irradiation time of the predetermined X-ray pulse included in the predetermined irradiation condition.

[0129] However, it is not limited thereto. According to various embodiments of the present disclosure, as the irradiation dose increases, the brightness information of the first radiographic image may become darker. For example, the control unit 200 may use an inverted image that inverts the pixel values ​​of the image acquired from the image acquisition unit 112. Therefore, as the irradiation dose increases, the brightness information of the first radiographic image as the inverted image may become darker. At this time, when the brightness information is less than the predetermined first critical brightness information, the first irradiation condition may be less than the predetermined irradiation condition. That is, when the brightness information is less than the predetermined first critical brightness information, at least one of the first tube voltage, the first tube current, and the irradiation time of the first X-ray pulse included in the first irradiation condition may be less than at least one of the predetermined tube voltage, the predetermined tube current, and the irradiation time of the predetermined X-ray pulse included in the predetermined irradiation condition. In addition, when the brightness information is greater than the predetermined first critical brightness information, the first irradiation condition may be greater than the predetermined irradiation condition. That is, when the brightness information is greater than the predetermined first critical brightness information, at least one of the first tube voltage, the first tube current, and the irradiation time of the first X-ray pulse included in the first irradiation condition may be greater than at least one of the predetermined tube voltage, the predetermined tube current, and the irradiation time of the predetermined X-ray pulse included in the predetermined irradiation condition.

[0130] As described above, the control unit 200 may determine a first irradiation condition including at least one of a first tube voltage, a first tube current, and an irradiation time of a first X-ray pulse so that the brightness information of the first radiographic image is the same as the predetermined brightness information. The first irradiation condition may be different from the predetermined irradiation condition. However, in certain cases, the first irradiation condition may also be the same as the predetermined irradiation condition. The control unit 200 may make the brightness information of a radiographic image generated after the first radiographic image the same as the predetermined brightness information based on the first irradiation condition.

[0131] The control unit 200 can repeatedly acquire the first irradiation condition at a predetermined cycle. The radiation imaging device 100 can provide a video, and the irradiated object can continuously change. The radiation imaging device 100 can continuously acquire the first irradiation condition, thereby irradiating radiation, and can provide the user with the best radiation image.

[0132] Refer again Figure 3 , the control unit 200 may perform step (340), that is, control the dose of radiation based on the first irradiation condition. Step (340) may be performed by the irradiation control unit 204. As described above, the dose of radiation may be determined based on at least one of the first tube voltage, the first tube current, and the irradiation time of the first X-ray pulse included in the first irradiation condition.

[0133] The control unit 200 may execute step (350), i.e., obtain a second radiographic image contained in a continuous radiographic image and generated based on a first irradiation condition. The second radiographic image may be a radiographic image generated after the first radiographic image. The second radiographic image may be contained in a continuous radiographic image. The second radiographic image may include at least one frame image in a video. In addition, as long as the first radiographic image is an image based on a predetermined irradiation condition, the second radiographic image may be an image based on the first irradiation condition. The subject appearing in the second radiographic image is similar to the predetermined brightness information, so the subject may clearly appear in the second radiographic image. Therefore, the user can easily diagnose the patient based on the second radiographic image. However, the second radiographic image may not be an image based on the lowest dose. In order to maintain image quality while utilizing the lowest dose, the radiographic image shooting device 100 may further perform the following process.

[0134] The control unit 200 may execute step (360), that is, obtain movement information indicating whether the imaging part of the subject is fixed. The movement information may be obtained from the user through the input unit 250. For example, after confirming that the subject is stationary, the user may input the movement information to the radiation imaging device 100.

[0135] However, the present invention is not limited thereto, and the movement information may be automatically acquired. More specifically, the step of acquiring the movement information (360) may include the following process.

[0136] The control unit 200 may perform a step of determining that the movement information indicates that the photographing part of the object is not fixed when the time for acquiring at least one of the first radiographic image and the second radiographic image is less than a predetermined critical time. The critical time may be a time sufficient to fix the patient. In the main environment, the object may be a patient who is a surgical object. For surgery, the patient may be in an anesthetized state. When the patient is placed in the radiographic imaging device, the patient may not move substantially. Therefore, when the time for the radiographic imaging device 100 to start acquiring at least one of the first radiographic image and the second radiographic image starts to be less than a predetermined critical time, the control unit 200 may determine that the movement information indicates that the photographing part of the object is not fixed. Among them, the time for starting to acquire the first radiographic image may mean the time for starting to acquire the initial radiographic image for the object. In addition, the time for starting to acquire the second radiographic image may mean the time for starting to acquire the radiographic image according to the first irradiation condition. The time for starting to acquire the second radiographic image may be the time for ending the acquisition of the first radiographic image. The difference between the time for starting to acquire the first radiographic image and the time for starting to acquire the second radiographic image may be within 5 seconds.

[0137] When the time for acquiring at least one of the first radiation image and the second radiation image is longer than a predetermined critical time, the control unit 200 may perform a step of determining whether the movement information indicates that the imaging part of the subject is fixed. That is, the radiation imaging device 100 may assume that the subject is fixed after the predetermined critical time.

[0138] The control unit 200 may execute step (370), that is, when the movement information indicates that the imaging part of the object is fixed, determine the second irradiation condition based on the second radiographic image according to the second algorithm. Step (370) may be executed by the second irradiation condition calculation unit 205.

[0139] The first algorithm for determining the first illumination condition and the second algorithm for determining the second illumination condition may be different. Figure 5 .

[0140] Figure 5 is a flowchart showing the operation of the radiation imaging device according to one embodiment of the present disclosure. Figure 6 It may be a diagram for explaining downsampling according to one embodiment of the present disclosure.

[0141] Reference Figure 5 and Figure 6, the step of determining the second irradiation condition (370) may include the following operations. The control unit 200 may perform a step of downsampling the second radiographic image 610 in units of patches 611 of a predetermined size to obtain a downsampled image 620. The patches 611 of a predetermined size may be smaller than the second radiographic image 610. If the size of the second radiographic image 610 is n×m, the size of the patches 611 of a predetermined size may be a×b. n may be the number of pixels on the horizontal axis contained in the second radiographic image 610, and m may be the number of pixels on the vertical axis contained in the second radiographic image 610. In addition, a may be the number of pixels on the horizontal axis of the patches 611 of a predetermined size, and b may be the number of pixels on the vertical axis of the patches 611 of a predetermined size. n may be greater than or equal to a, and m may be greater than or equal to b.

[0142] The control section 200 may determine one of the average, minimum, maximum, and median values ​​of the pixel values ​​of the pixels included in the block 611 of a predetermined size in the second radiographic image 610 as the pixel value of one pixel 621 of the downsampled image 620. The control section 200 may determine one of the average, minimum, maximum, and median values ​​of the pixel values ​​of the pixels included in the next block 612 of a predetermined size in the second radiographic image 610 as the pixel value of one pixel 622 of the downsampled image 620. The sizes of the block 611 of a predetermined size and the next block 612 of a predetermined size may be the same and may not overlap each other. The control section 200 may obtain the downsampled image 620 by repeating the above process for the entire second radiographic image 610.

[0143] In the above, the blocks 611 and 612 of predetermined size do not overlap with each other, but are not limited to this. The blocks of predetermined size may overlap with each other. For example, the control unit 200 may determine one of the average, minimum, maximum and median values ​​of the pixel values ​​of the pixels contained in the block 631 of predetermined size in the second radiographic image 630 as the pixel value of one pixel 641 of the downsampled image 640. The control unit 200 may determine one of the average, minimum, maximum and median values ​​of the pixel values ​​of the pixels contained in the next block 632 of predetermined size in the second radiographic image 630 as the pixel value of one pixel 642 of the downsampled image 640. The size of the block 631 of predetermined size and the size of the next block 632 of predetermined size may be the same and may overlap with each other. The control unit 200 may obtain the downsampled image 640 by repeating the process described above for the entire second radiographic image 630. When the blocks of predetermined size are repeatedly downsampled, the downsampled image 640 may be larger than the downsampled image 620.

[0144] In the above, the entire area of ​​the second radiographic image 630 is downsampled, but it is not limited to this. The control unit 200 may downsample the area of ​​interest in the second radiographic image to obtain a downsampled image. The area of ​​interest may be an area selected by a user, or may be an area automatically selected by the radiographic imaging device 100. For example, the area of ​​interest may be an area where the subject appears. Since the area where the subject appears has been described, repeated description is omitted.

[0145] The control unit 200 may perform a step of obtaining a minimum pixel value among pixel values ​​included in one of the downsampled images 620 and 640. The control unit 200 may perform a step of determining a second irradiation condition so that the minimum pixel value is the same as the second critical brightness information when the minimum pixel value is greater than the predetermined second critical brightness information. The control unit 200 may perform a step of determining that the second irradiation condition is the same as the first irradiation condition when the minimum pixel value is less than or equal to the predetermined second critical brightness information. The control unit 200 may not determine the second irradiation condition when the minimum pixel value is less than or equal to the predetermined second critical brightness information. The second critical brightness information may be obtained based on the performance of the detector. The second critical brightness information may be the minimum pixel value that can be processed without any problem in at least one of the image acquisition unit 112 and the image post-processing unit 207 included in the control unit 200, and may be a predefined constant. When the performance of the image acquisition unit 112 and the image post-processing unit 207 is poor, a noise component may exist in the pixel, and a value below a specific pixel value may not be a value caused by radiation, but a value caused by noise. Therefore, the second critical brightness information may be a value related to the minimum radiation dose that can indicate that the pixel is excited by radiation. That is, the better the performance of the image acquisition unit 112 and the image post-processing unit 207 is, the smaller the second critical brightness information may be.

[0146] Reference Figure 7 , said step of determining the second illumination condition so that the minimum pixel value is the same as the second critical brightness information.

[0147] Figure 7 is a flowchart for explaining a process for acquiring the second irradiation condition according to one embodiment of the present disclosure.

[0148] The step of determining the second illumination condition so that the minimum pixel value is the same as the second critical brightness information may include the following process.

[0149] The control unit 200 may perform step (710), i.e., determine the reduction ratio based on the minimum pixel value and the second critical brightness information. The second critical brightness information may be the minimum pixel value that can be processed without any problem in at least one of the image acquisition unit 112 and the image post-processing unit 207 included in the control unit 200, and may be a predefined constant. The reduction ratio may be greater than or equal to 0 and less than or equal to a predetermined maximum reduction ratio. The maximum reduction ratio may be greater than 65% and less than 75%. For example, the maximum reduction ratio may be 70%. The unit of the reduction ratio may be a percentage. However, it is not limited thereto.

[0150] The control unit 200 may obtain the reduction ratio based on the following equation.

[0151] Reduction ratio = min(max(1-second critical brightness information / minimum pixel value, 0), maximum reduction ratio)*100

[0152] The radiation dose based on the second irradiation condition may be greater than or equal to 30% of the radiation dose based on the first irradiation condition. When the reduced dose is determined to be 70% as the maximum reduction ratio, the radiation dose based on the second irradiation condition may be 30% of the radiation based on the first irradiation condition.

[0153] The control section 200 may perform step ( 720 ) of determining the second irradiation condition so that the radiation irradiation section irradiates a dose obtained by subtracting the dose according to the first irradiation condition by multiplying the dose according to the first irradiation condition by the reduction ratio.

[0154] The second irradiation condition may include at least one of the second tube voltage, the second tube current, and the irradiation time of the second X-ray pulse. The control unit 200 may determine at least one of the second tube voltage, the second tube current, and the irradiation time of the second X-ray pulse based on the reduction ratio determined in step (710). For example, the greater the at least one of the second tube voltage and the second tube current, the greater the irradiation dose of the X-ray. The irradiation time of the second X-ray pulse is a value proportional to the time for the X-ray source to emit X-rays, so that the longer the irradiation time of the second X-ray pulse, the greater the irradiation dose of the X-ray. In addition, as the irradiation dose increases, the brightness information of the radiographic image may become brighter. However, it is not limited to this, and as the irradiation dose increases, the brightness information of the radiographic image may become darker. The control unit 200 may determine the second irradiation condition including at least one of the second tube voltage, the second tube current, and the irradiation time of the second X-ray pulse according to the reduction ratio. The second irradiation condition may be different from the first irradiation condition. However, in certain cases, the second irradiation condition may also be the same as the first irradiation condition.

[0155] At least one of the second tube current and the irradiation time of the second X-ray pulse may have a linear relationship with the irradiation dose. In addition, the second tube voltage may have a nonlinear relationship with the irradiation dose. The control unit 200 may determine at least one of the second tube current and the irradiation time of the second X-ray pulse by reducing at least one of the first tube current and the irradiation time of the first X-ray pulse according to a reduction ratio. However, not limited thereto, the control unit 200 may determine at least one of the second tube current and the irradiation time of the second X-ray pulse corresponding to the reduction ratio by applying at least one of the first tube current and the irradiation time of the first X-ray pulse to a predetermined reduction ratio determination function or a reduction ratio determination table. In addition, the control unit 200 may obtain a voltage reduction ratio corresponding to the reduction ratio based on a voltage reduction ratio determination function or a voltage reduction ratio determination table. The control unit 200 may determine the second tube voltage by reducing the first tube voltage according to the voltage reduction ratio.

[0156] Refer again Figure 3 , the control unit 200 may perform step (380), that is, control the dose of radiation based on the second irradiation condition. Step (380) may be performed by at least one of the dose reduction unit 206 and the irradiation control unit 204. As described above, the second irradiation condition may be determined based on the first irradiation condition and the reduction ratio. The radiation dose based on the second irradiation condition may be less than or equal to the radiation dose based on the first irradiation condition. That is, the control unit 200 may determine the dose of the second irradiation condition according to the second irradiation condition by the following formula.

[0157] Dose under the second irradiation condition = Dose under the first irradiation condition * (1-reduction ratio / 100)

[0158] The control unit 200 may perform step (390), i.e., acquire a third radiographic image included in the continuous radiographic images and generated based on the second irradiation condition. The third radiographic image may be a radiographic image generated after the second radiographic image. The third radiographic image may be included in the continuous radiographic images. The third radiographic image may include at least one frame image in the video.

[0159] In addition, if the second radiographic image is an image based on the first irradiation condition, the third radiographic image may be an image based on the second irradiation condition. The third radiographic image may maintain substantially the same quality as the second radiographic image. That is, the clarity and noise of the subject appearing in the third radiographic image may be substantially the same as the clarity and noise of the subject appearing in the second radiographic image. However, the dose of radiation irradiated to the subject in order to obtain the third radiographic image may be less than or equal to the dose of radiation irradiated to the subject in order to obtain the second radiographic image.

[0160] The control unit 200 can repeatedly acquire the second irradiation condition at a predetermined cycle. The radiation imaging device 100 can provide a video, and the irradiated object can continuously change. The radiation imaging device 100 can continuously acquire the second irradiation condition, thereby irradiating radiation, so that the radiation image of the irradiated object can be acquired at a low dose while maintaining the high quality of the radiation image.

[0161] According to the radiation imaging device 100 of one embodiment of the present disclosure, the control unit 200 can fix the second irradiation condition based on the user's input or a predetermined condition. When the control unit 200 fixes the second irradiation condition, when an object other than the irradiated object further enters the shooting area, the second irradiation condition is not changed, so that the effect of maintaining a low dose can also be expected. For example, when medical equipment or the like enters the shooting area, the radiation imaging device 100 can maintain a low dose according to the second irradiation condition without changing the irradiation amount of radiation but changing the brightness of the radiation image.

[0162] In order to improve the image quality, the third radiographic image may be post-processed. The following describes the process of post-processing the third radiographic image.

[0163] Figure 8 1 is a diagram for explaining the operation of the radiation imaging device according to one embodiment of the present disclosure.

[0164] The step (390) of acquiring the third radiographic image may include the following process. The control unit 200 may perform the following step, namely, generating an improved current frame image 840 by cumulatively averaging pixel values ​​included in at least a portion of the current frame image 830 included in the third radiographic image and pixel values ​​included in at least a portion of the previous frame image 820 included in the third radiographic image. The step of acquiring the improved current frame image 840 may be performed in the image post-processing unit 207 included in the control unit 200.

[0165] As described above, the third radiographic image may include a current frame image 830 and a previous frame image 820. The current frame image may be a frame most recently acquired by the image acquisition unit 112. The previous frame image 820 may be at least one frame image acquired before the current frame image. The previous frame image 820 may include a previous frame image 822 and an n-2 frame image 821. The previous frame image may be a frame image previous to the current frame image.

[0166] The control unit 200 can generate an improved current frame image 840 by accumulating and averaging the current frame image 830 and a predetermined number of previous frame images 820. The predetermined number can be greater than or equal to 1. The predetermined number can refer to the number of frames. In the following, for ease of explanation, the case where the predetermined number is 1 is described. The same description can also be applied to the case where the predetermined number is 2 or more.

[0167] The control unit 200 may perform cumulative averaging on the pixel value of a pixel of the current frame image 830 and the pixel value of the previous frame image 820 at a position corresponding to the pixel of the current frame image. The radiation imaging device 100 may accumulate the average pixel value between the pixels at the corresponding positions in the current frame image 830 and the previous frame image 820 to obtain the pixel value included in the improved current frame image 840. The so-called pixels at the corresponding positions refer to the position (coordinate value) of the pixel in the current frame image 830 being the same as the position (coordinate value) of the pixel in the previous frame image 820. The control unit 200 may generate the improved current frame image 840 by obtaining the cumulative average value of all pixels included in the current frame image 830 and all pixels included in the previous frame image 820. However, the control unit 200 may generate the improved current frame image 840 by obtaining the cumulative average value of the pixel values ​​of the pixels included in at least a portion of the current frame image 830 and the pixel values ​​of the pixels included in at least a portion of the previous frame image 820. At least a portion of the current frame image 830 may be at least one of a region of interest or a region where the object appears.

[0168] As described above, since the object does not move, the change in the pixel value of the pixel at the same position in the continuous frame images can be small. Therefore, as described above, when the improved current frame image is obtained by cumulative averaging, the influence of noise can be minimized. This is because noise is generated by a large change in the pixel value of a pixel.

[0169] Fig. 9 is a flowchart illustrating the operation of the radiation imaging apparatus according to one embodiment of the present disclosure. Fig.10 1 is a schematic diagram for explaining the operation of the radiation imaging device according to one embodiment of the present disclosure. Fig.11 1 is a schematic diagram for explaining the operation of the radiation imaging device according to one embodiment of the present disclosure. Fig.12 1 is a schematic diagram for explaining the operation of the radiation imaging device according to one embodiment of the present disclosure.

[0170] Figures 9 to 12 This may be performed by the image post-processing section 207 included in the control section 200. The image post-processing section 207 does not control the radiation irradiation section 111, but corrects the first to third radiographic images acquired by software, thereby outputting high-quality improved radiographic images.

[0171] The image post-processing unit 207 included in the control unit 200 may further perform the following process when executing the step (390) of acquiring the third radiation image.

[0172] Reference Fig. 9 , the control unit 200 may execute step (910), i.e., generate a motion detection image, wherein the motion detection image includes motion detection information of each pixel of a differential image obtained by differentially dividing a current frame image contained in the third radiographic image and a previous frame image contained in the third radiographic image.

[0173] More specifically, refer to Fig. 9 and Fig.10 , the control unit 200 can generate a motion detection image by threshold processing of the differential image. Fig.10 As shown, a motion detection image 1010 may be generated from the noise-processed current frame image 830 and the previous frame image 820. The motion detection image 1010 may be obtained based on a subtracted image obtained by subtracting the previous frame image 820 from the current frame image 830.

[0174] The control unit 200 generates a differential image by performing a difference between the current frame image 830 and the previous frame image 820 that have completed the noise processing, i.e., the noise reduction and noise stabilization processing. In order to reduce noise, the control unit 200 can obtain the sum of the absolute values ​​of the differences between the pixel values ​​of any two pixels in the upper left, upper side, upper right side, left side, right side, lower left side, lower side, and lower right side pixels adjacent to the center pixel as the noise reduction object and the center pixel. The selected adjacent pixels can be appropriately determined according to needs and required conditions. For example, taking the center pixel as a reference, the sum of the absolute values ​​of the differences between two pixels in the upper left, upper side, upper right side, left side, right side, lower left side, lower side, and lower right side and the center pixel is calculated respectively.

[0175] For example, the control unit 200 can obtain the sum of the absolute values ​​of the difference between the pixel value of the center pixel and the pixel value of the upper left pixel and the difference between the pixel value of the center pixel and the pixel value of the upper pixel (A1), the sum of the absolute values ​​of the difference between the pixel value of the center pixel and the pixel value of the upper left pixel and the difference between the pixel value of the center pixel and the pixel value of the upper right pixel (A2), the sum of the absolute values ​​of the difference between the pixel value of the center pixel and the pixel value of the upper left pixel and the difference between the pixel value of the center pixel and the pixel value of the left pixel (A3), the sum of the absolute values ​​of the difference between the pixel value of the center pixel and the pixel value of the upper left pixel and the difference between the pixel value of the center pixel and the pixel value of the left pixel (A4), the sum of the absolute values ​​of the difference between the pixel value of the center pixel and the pixel value of the upper left pixel and the difference between the pixel value of the center pixel and the pixel value of the upper right pixel (A5), the sum of the absolute values ​​of the difference between the pixel value of the center pixel and the pixel value of the upper left pixel and the difference between the pixel value of the center pixel and the pixel value of the upper left pixel (A6), the sum of the absolute values ​​of the difference between the pixel value of the center pixel and the pixel value of the upper left pixel and the difference between the pixel value of the center pixel and the pixel value of the upper right pixel (A7). and the sum of the absolute values ​​of the difference between the pixel value of the center pixel and the pixel value of the pixel on the right (A4), the sum of the absolute values ​​of the difference between the pixel value of the center pixel and the pixel value of the upper left pixel, and the difference between the pixel value of the center pixel and the pixel value of the lower left pixel (A5), the sum of the absolute values ​​of the difference between the pixel value of the center pixel and the pixel value of the upper left pixel, and the difference between the pixel value of the center pixel and the pixel value of the lower pixel (A6), and the sum of the absolute values ​​of the difference between the pixel value of the center pixel and the pixel value of the upper left pixel, and the difference between the pixel value of the center pixel and the pixel value of the lower right pixel (A7). The control unit 200 can obtain the sum of the absolute values ​​of the difference between the pixel value of the center pixel and the pixel value of the upper pixel and the pixel value of the upper right pixel (A8), the control unit 200 can obtain the sum of the absolute values ​​of the difference between the pixel value of the center pixel and the pixel value of the upper pixel and the pixel value of the left pixel (A9), the absolute values ​​of the difference between the pixel value of the center pixel and the pixel value of the upper pixel and the pixel value of the right pixel The sum of the absolute values ​​of the difference between the pixel value of the center pixel and the pixel value of the upper pixel and the pixel value of the lower left pixel (A11), the sum of the absolute values ​​of the difference between the pixel value of the center pixel and the pixel value of the upper pixel and the pixel value of the lower pixel (A12), the sum of the absolute values ​​of the difference between the pixel value of the center pixel and the pixel value of the upper pixel and the pixel value of the lower right pixel (A13). The control unit 200 can determine the sum of the absolute values ​​of the differences from the surrounding pixels of the center pixel through the process described above. That is, the control unit 200 can obtain the sum of absolute values ​​(A1 to A29) through the process described above. At this time, the direction with a smaller absolute value sum (Ak) can be considered as the pixel with the most similar directionality to the center pixel. For example, if A1 is the smallest among A1 to A29, the upper left pixel and the upper pixel may be selected, and the direction to the upper left pixel, the center pixel, and the upper pixel in that order may be selected.

[0176] Impulse noise can be regarded as a pixel with a particularly large absolute value compared to the surrounding pixels, so in order to exclude it, the control unit 200 can use the pixel values ​​of the two adjacent pixels whose absolute values ​​of the differences between the two selected adjacent pixels and the pixel value of the central pixel are the smallest to correct the pixel value of the central pixel and update it to a pixel value with reduced noise. For example, the control unit 200 can replace the pixel value of the central pixel with the average value or the middle value of the pixel value of the central pixel and the pixel values ​​of the two selected pixels. By sequentially updating the pixel value of the central pixel in this way while moving the mask, noise reduction through pixel values ​​can be achieved.

[0177] The embodiment of considering the pixels around the central pixel in one frame is described above, but it is not limited thereto. The control unit 200 may also use at least one of the previous frame and the next frame of the current frame. The next frame is an image acquired from the image acquisition unit 112, and thus may be a frame acquired after the current frame. The current frame may be a frame in noise processing, and the next frame may be a frame before noise processing. The previous frame may be a frame before the current frame, and may be a frame for which noise processing has been completed.

[0178] The control unit 200 can obtain the absolute value of the difference between the pixel value of the central pixel of the previous frame located at the same position as the central pixel of the current frame, and any at least one of the upper left, upper side, upper right side, left side, right side, lower left side, lower side, and lower right side pixels adjacent thereto, and the central pixel of the current frame. In addition, the control unit 200 can obtain the absolute value of the difference between the pixel value of the central pixel of the next frame located at the same position as the central pixel of the current frame, and any at least one of the upper left, upper side, upper right side, left side, right side, lower left side, lower side, and lower right side pixels adjacent thereto, and the central pixel of the current frame. The control unit 200 can select two pixels with the smallest sum of two absolute values. The control unit 200 can replace the pixel value of the central pixel of the previous frame with the pixel value of the central pixel of the current frame and the average value or the middle value of the pixel values ​​of the selected two pixels.

[0179] The control unit 200 can stabilize the noise by reducing the deviation between the noise of the current frame image and the previous frame image. For example, in order to obtain a radiographic image, the amount of photons incident on each sensor is not constant over time, but appears randomly and has independence, so the noise characteristics of the radiographic image generally follow a Poisson distribution. In an embodiment of the present disclosure, in order to remove noise with Poisson distribution characteristics, the noise is approximated to a Gaussian distribution characteristic through a variance invariance transformation (Anscombe transform). The variance invariance transformation is a transformation approximated to a Gaussian distribution with a standard deviation close to 1, so the converted data has a stable noise deviation.

[0180] The control unit 200 can generate a differential image by calculating the difference between the pixel values ​​of all pixels at the same position between the current frame image 830 and the previous frame image 820. The differential image may include the movement information of the object and the residual noise information. In addition, an average filter or a median filter may be used in the generated differential image to stabilize the differential image.

[0181] The control unit 200 can determine the critical pixel value for motion detection of the differential image and perform threshold processing based on the determined critical pixel value, so as to detect whether each pixel moves and generate a motion detection image 1010 accordingly. When the critical pixel value for motion detection is set too low, the motion detection sensitivity is improved and the noise level is reduced. Conversely, when the critical pixel value is too high, the motion detection sensitivity is reduced, and motion blur (drag phenomenon) may occur. Since X-ray images are acquired under different dose conditions and subject characteristics, it is difficult to predict the pixel value of the acquired image, and an appropriate critical pixel value needs to be set according to the pixel value.

[0182] The control unit 200 according to an embodiment of the present disclosure may apply an adaptive critical pixel value, the size of which varies according to the size of the pixel value of each pixel of the differential image. For example, the critical pixel value for movement determination may be set to become smaller as the pixel value of the pixel increases.

[0183] When the absolute value of the pixel value of the pixel included in the subtracted image is a value above the predetermined critical pixel value, the control unit 200 can make the pixel value of the corresponding pixel included in the motion detection image 1010 become "0", and when the absolute value of the pixel value of the pixel included in the subtracted image is less than the predetermined critical pixel value, the pixel value of the corresponding pixel included in the motion detection image 1010 can become "1". However, it is not limited to this. The control unit 200 can make the pixel value of the corresponding pixel included in the motion detection image 1010 become "1" when the absolute value of the pixel value of the pixel included in the subtracted image is above the predetermined critical pixel value, and when the absolute value of the pixel value of the pixel included in the subtracted image is less than the predetermined critical pixel value, the pixel value of the corresponding pixel included in the motion detection image 1010 can become "0".

[0184] The motion detection image 1010 may include information on whether each pixel is moving. For example, it may be set that pixels with movement have a value of "0", and pixels without movement have a value of "1". That is, all pixels of the motion detection image 1010 have a pixel value of 0 or 1, and a pixel with a value of 0 means that there is still movement based on the previous frame image, and a pixel with a value of "1" may mean that there is no movement based on the previous frame image. But it is not limited to this.

[0185] The control unit 200 can generate an improved current frame image 840 based on the motion detection image 1010. Figure 8 As shown, the control unit 200 may perform the following steps, namely, by accumulating and averaging the pixel values ​​included in at least a portion of the current frame image 830 included in the third radiographic image and the pixel values ​​included in at least a portion of the previous frame image 820 included in the third radiographic image, to generate an improved current frame image 840. At this time, the control unit 200 may also use the motion detection image 1010. More specifically, the control unit 200 determines the pixel value of the current frame image 830 as the pixel value of the improved current frame image 840 for the pixel in which the motion is detected in the motion detection image 1010, and for the pixel in which the motion is not detected, the pixel value of the improved current frame image 840 may be determined by accumulating and averaging the pixel value of the current frame image 830 and the pixel value of the previous frame image 820. However, the control unit 200 is not limited thereto, and may use the motion probability image instead of the motion detection image 1010 to generate the improved current frame image 840.

[0186] Refer again Fig. 9 The control unit 200 may execute step (920), that is, generate a motion probability image based on the generated motion detection image and the motion detection image accumulated up to the previous frame.

[0187] Reference Fig. 9 and Fig.10 , the control unit 200 may accumulate the motion detection results in a separate memory in a time sequence to generate a motion probability image 1020. The motion probability image 1020 may be used to determine an appropriate mixing ratio of the previous frame image 820 and the current frame image 830 to generate an improved current frame image 840. As described above, the previous frame image 820 may include at least one frame. The current frame image 830 may include one frame.

[0188] The control unit 200 performs the following process to execute the step (920) of generating a motion probability image: The control unit 200 may generate the motion probability image 1020 by adding one or more of the motion detection image 1010 of the current frame and the motion detection images up to the previous frame.

[0189] More specifically, Fig.11 1 is a schematic diagram showing a method of generating a motion probability image 1020 using a motion detection image 1010. The control unit 200 may accumulate and store the motion detection image 1010 obtained by motion detection in an independent memory in a time sequence for each frame, and generate and update the motion probability image 1020. Fig.11The left image of shows the accumulated motion detection image 1110, and the right image shows the motion probability image 1120 obtained by adding the motion detection images. The motion probability image 1120 of the current frame can be generated by adding the values ​​of the same pixels of the motion probability image of the previous frame and the motion detection image 1010 of the current frame. That is, the motion probability image 1120 of a specific frame is an image obtained by adding the pixel values ​​of the same pixels of all the motion detection images obtained up to that frame. For example, referring to Fig.11 If the current frame is the fourth frame, the sum of the values ​​of the same pixels in the motion detection images obtained from the four frames so far becomes the value of the same pixel in the motion probability image of the current frame.

[0190] When the value of a pixel judged to have movement in a motion detection image is represented by "0" to indicate brightness, and the value of a pixel judged to have no movement is represented by "1" to indicate darkness, each pixel of the motion probability image has a value corresponding to the sum of the motion detection values ​​(0 or 1) of the pixel, thereby having different values ​​according to the number of motion judgments, that is, having different brightness. For example, assuming a motion probability image composed of 10 frames, the motion probability image is obtained by adding 10 motion detection images, and each pixel of the motion probability image has one of the values ​​from 0 to 10. Among them, when the values ​​of the same pixels of all motion detection images are 0, the corresponding pixels of the motion probability image have a value of 0, and if the values ​​of the same pixels of all motion detection images are 1, the corresponding pixels of the motion probability image have a value of 10. Therefore, if Fig.10 As shown, each pixel of the motion probability image has a pixel value, that is, brightness, according to the number of motion detections of the same pixel in the motion detection image up to that frame.

[0191] In this sense, in the generated motion probability image 1020, it can be considered that the brighter the pixel value, the higher the motion probability, and the darker the pixel value, the lower the motion probability. For example, when frames are processed in time sequence at the same pixel position, if motion is detected, the motion probability will be higher, and if no motion is detected, the motion probability will be lower.

[0192] The value of each pixel of the motion probability image 1020 indicates the degree of motion of the corresponding pixel and the motion probability value. That is, if a judgment value of "0" is assigned when there is motion and a judgment value of "1" is assigned when there is no motion, the smaller the pixel value of the motion probability image 1020 is, the greater the motion probability of the corresponding pixel is.

[0193] Fig.12The example of the generation process of the motion detection image 1010 and the motion probability image 1020 according to the input image according to the progress of the frame is shown. The motion detection image is generated by the difference between the frame image of each frame and the previous frame image, and the motion probability image 1020 can be generated again by adding the motion detection image and the motion detection image of the previous frame.

[0194] Reference Fig. 9 , the control unit 200 may execute step (930), that is, based on the motion probability image, mix the current frame image and the previous frame image to generate an improved current frame image.

[0195] In order to perform the step (930) of generating the improved current frame image, the control unit 200 may perform the step of variably determining the mixing ratio of the current frame image 830 and the previous frame image 820 according to the value representing the degree of movement of each pixel of the motion probability image 1020. In addition, the control unit 200 may determine the mixing ratio so that the greater the degree of movement represented by the value of each pixel of the motion probability image 1020, the greater the reaction ratio of the current frame image compared with the previous frame image.

[0196] The current frame image 830 may be a current frame image in a state of reducing noise by the control unit 200, and the previous frame image 820 may be a previous frame image in which noise is reduced by the control unit 200. In addition, the previous frame image 820 may be a frame image improved in the past, or may be an unimproved frame image. At this time, the control unit 200 may generate an improved current frame image 840 by mixing the current frame image 830 and the previous frame image 820 at an appropriate mixing ratio based on the motion probability image 1020. That is, the control unit 200 may perform weighted averaging on the current frame image 830 and the previous frame image 820 based on the motion probability image 1020.

[0197] The greater the degree of movement indicated by the value of each pixel of the motion probability image 1020, the greater the reaction ratio of the current frame image 830. That is, the higher the probability of movement determined by the pixel value included in the motion probability image 1020, the higher the weight of the current frame image 830 can be determined for the mixing ratio. For example, in terms of pixel units, the greater the degree of movement indicated by the pixel value of the motion probability image 1020, the greater the reaction ratio can be determined so that the reaction ratio of the current frame image 830 increases linearly.

[0198] Specifically, for pixels that move more, a predetermined weight (α1), for example, 0.8, is assigned to the corresponding pixels of the current frame image 830, and a weight (1-α1), for example, 0.2, is assigned to the corresponding pixels of the previous frame image 820, and this mixing process can be performed on all pixels.

[0199] On the other hand, for pixels with less movement, a predetermined weight (α2), for example, 0.2, is assigned to the corresponding pixels of the current frame image 830, and a weight (1-α2), for example, 0.8, is assigned to the corresponding pixels of the previous frame image 820, so that the current frame image 830 and the previous frame image 820 can be mixed. For pixels with more movement, if the weight of the current frame image 830 is increased, an image without motion blur can be obtained. As a result, the improved current frame image 840 is updated based on the movement probability, and the pixels with more movement more reflect the values ​​of the current frame, and the pixels with less movement more reflect the values ​​of the previous frame, and the noise reduction performance can be improved by accumulating frames over time.

[0200] So far, the review has been centered around various embodiments. It will be understood by those of ordinary skill in the art to which the present disclosure belongs that the present disclosure can be implemented in a modified form without departing from the essential characteristics of the present disclosure. Therefore, the disclosed embodiments should be considered from an illustrative perspective rather than a limiting perspective. The scope of the present disclosure is expressed in the scope of the invention claims, rather than the above description, and all differences within the equivalent scope thereof should be interpreted as being included in the present disclosure.

[0201] On the other hand, the above-mentioned embodiments of the present disclosure can be written by a computer executable program and can be implemented in a general-purpose digital computer that uses a computer-readable recording medium to operate the program. The computer-readable recording medium includes a magnetic storage medium (e.g., a read-only memory, a floppy disk, a hard disk, etc.), an optical reading medium (e.g., a CD-ROM, a digital video disk, etc.), and other storage media.

Claims

1. A radiographic imaging device, wherein: include: An image output unit that outputs a first radiographic image included in a series of radiographic images obtained by radiographically photographing a subject; an image brightness information extraction unit, which obtains brightness information from the first radiation image; a first irradiation condition calculation unit, which determines a first irradiation condition based on the brightness information; an irradiation control unit that controls a dose of radiation based on the first irradiation condition; a second irradiation condition calculation unit that determines a second irradiation condition based on a second radiographic image generated based on the first irradiation condition when the imaging part of the object is fixed; and The dose reducing unit reduces or maintains the radiation dose based on the second irradiation condition.

2. The radiation imaging device according to claim 1, wherein: A value of the radiation dose based on the first irradiation condition minus the radiation dose based on the second irradiation condition is less than or equal to 70% of the dose based on the first irradiation condition.

3. The radiation imaging device according to claim 1, wherein: When the dose reduction is caused by the dose reducing unit, the first irradiation condition calculating unit is disabled.

4. The radiation imaging device according to claim 1, wherein: An improved current frame image is generated by cumulatively averaging pixel values ​​of a current frame image included in a third radiation image output according to the dose reduced by the dose reducing section and pixel values ​​of a previous frame image included in the third radiation image.

5. The radiation imaging device according to claim 1, wherein: The radiation imaging device further includes an image post-processing unit for post-processing a third radiation image outputted according to the dose reduced by the dose reducing unit. The image post-processing section adjusts at least one of the brightness information and the contrast information of the third radiographic image similarly to at least one of the brightness information and the contrast information of the second radiographic image.

6. A method for operating a radiographic imaging device, the device comprising: A radiation irradiation unit irradiates radiation to an object; an image acquisition unit, receiving radiation irradiated from the radiation irradiation unit and passing through the irradiated object, so as to generate a continuous radiation image; as well as A control unit controls the radiation irradiation unit and the image acquisition unit, wherein: The method comprises: The control unit acquires brightness information based on a first radiographic image included in the continuous radiographic images; a step of determining a first illumination condition based on the brightness information according to a first algorithm; a step of controlling a dose of radiation based on the first irradiation condition; a step of acquiring a second radiographic image included in the continuous radiographic images and generated based on the first irradiation condition; A step of acquiring movement information indicating whether a photographing portion of the photographed object is fixed; When the movement information indicates that the imaging part of the object is fixed, a step of determining a second irradiation condition based on the second radiation image according to a second algorithm; a step of controlling a dose of radiation based on the second irradiation condition; and A step of acquiring a third radiographic image included in the continuous radiographic images and generated based on the second irradiation condition.

7. The operating method of the radiation imaging device according to claim 6, wherein: The radiation dose based on the second irradiation condition is greater than or equal to 30% of the radiation dose based on the first irradiation condition.

8. The operating method of the radiation imaging device according to claim 6, wherein: The first algorithm that determines the first illumination condition is different from a second algorithm that determines the second illumination condition.

9. The radiation imaging device according to claim 6, wherein: The step of acquiring the third radiographic image comprises: A step of generating an improved current frame image by cumulatively averaging pixel values ​​included in at least a portion of a current frame image included in the third radiographic image and pixel values ​​included in at least a portion of a previous frame image included in the third radiographic image.

10. The operating method of the radiation imaging device according to claim 6, wherein: The step of acquiring the third radiographic image comprises: a step of generating a motion detection image including motion detection information of each pixel of a differential image obtained by difference between a current frame image included in the third radiographic image and a previous frame image included in the third radiographic image; A step of generating a motion probability image based on the generated motion detection image and the motion detection image accumulated in the previous frame; and The step of mixing the current frame image and the previous frame image based on the motion probability image to generate an improved current frame image.

11. The operating method of the radiation imaging device according to claim 10, wherein: The steps of generating the motion probability image include: The step of generating the motion probability image by adding one or more of the motion detection image of the current frame and the motion detection image up to the previous frame, The steps of generating the improved current frame image include: a step of variably determining a mixing ratio of the current frame image and the previous frame image according to a value representing a degree of movement of each pixel of the motion probability image, The mixing ratio is determined so that the greater the degree of movement represented by the value of each pixel of the motion probability image, the greater the reaction ratio of the current frame image compared with the previous frame image.

12. The operating method of the radiation imaging device according to claim 6, wherein: The step of obtaining the brightness information comprises: a step of averaging pixel values ​​included in at least a portion of the first radiographic image to obtain the brightness information, The step of determining the first irradiation condition comprises: determining the first illumination condition so that when the brightness information is less than a predetermined first critical brightness information, the brightness information increases; and The first illumination condition is determined so that when the brightness information is greater than a predetermined first critical brightness information, the brightness information is reduced.

13. The operating method of the radiation imaging device according to claim 12, wherein: The step of averaging pixel values ​​included in at least a portion of the first radiation image to obtain the brightness information comprises: Based on the object region acquisition model, a step of acquiring the region where the object appears in the first radiographic image; and A step of averaging pixel values ​​contained in the area where the illuminated object appears to obtain the brightness information.

14. The operating method of the radiation imaging device according to claim 6, wherein: The step of determining the second irradiation condition comprises: The step of downsampling the second radiographic image in a patch unit of a predetermined size to obtain a downsampled image; A step of obtaining a minimum pixel value among the pixel values ​​contained in the downsampled image; and The second illumination condition is determined so that when the minimum pixel value is greater than predetermined second critical brightness information, the minimum pixel value is the same as the second critical brightness information.

15. The operating method of the radiation imaging device according to claim 14, wherein: The step of determining the second illumination condition so that the minimum pixel value is the same as the second critical brightness information comprises: A step of determining a reduction ratio based on the minimum pixel value and the second critical brightness information; and determining a second irradiation condition so that the radiation irradiation unit irradiates a dose obtained by subtracting a dose according to the first irradiation condition by multiplying the dose according to the first irradiation condition by the reduction ratio, The reduction ratio is greater than 0 and less than a predetermined maximum reduction ratio.

16. The operating method of the radiation imaging device according to claim 6, wherein: The steps to obtain the mobile or non-mobile information include: When the time for acquiring at least one of the first radiographic image and the second radiographic image is less than a predetermined critical time, determining that the movement information indicates that the photographing part of the subject is not fixed; and The step of determining that the movement information indicates that the imaging part of the object is fixed when the time for acquiring at least one of the first radiographic image and the second radiographic image is longer than a predetermined critical time.

Images