JP7484434B2 - Radiation image capturing device, radiation image capturing system, control device and program - Google Patents

Description

The present invention relates to a radiographic imaging device, a radiographic imaging system, a control device, and a program.

2. Description of the Related Art Various types of radiation imaging devices have been developed that generate electric charges in radiation detection elements according to the amount of irradiated radiation and read out the generated electric charges as image data.
It is also possible to obtain images (moving images) that capture the movement of a living body using a radiation image capturing device.

Since the radiographic imaging device can be configured as a portable panel type, it is expected that it will be used in a variety of situations, not only in association with a specific radiation generating device in an imaging room, but also in combination with a portable radiation generating device for use in a medical examination vehicle or for imaging a patient lying on a bed, etc. For this reason, it may happen that the radiographic imaging device and the radiation generating device cannot be synchronized. Even if they are configured to be synchronized, there may be cases where they cannot be synchronized properly due to poor communication, etc.

In this regard, Patent Document 1 discloses a technology in which a control unit determines whether it is possible to detect the rising edges of multiple radiation pulses generated by a radiation generating device, and based on the determination result, appropriately sets the operation mode of the radiation imaging device (referred to as "FPD" in Patent Document 1) to a pulse irradiation compatible mode in which the rising and falling edges of radiation pulses are detected and the timing of the charge accumulation operation is synchronized with the detected timing, or a continuous irradiation compatible mode in which the charge accumulation operation is performed at a predetermined time interval without detecting the rising and falling edges of the radiation pulses.

Patent document 2 also discloses a technology that has a continuous shooting mode that shoots both still and video images in addition to a still image mode for shooting still images and a video mode for shooting video, and when there is no instruction to shoot still images or video images, shoots in continuous shooting mode and enables the reading of image data for each frame, making it possible to handle both still and video shooting.

In a radiographic imaging device, even when radiation is not being irradiated, dark charges are generated in each radiation detection element due to thermal excitation caused by the heat of the radiation detection element, and the charges accumulated in the radiation detection element contain an offset due to this dark charge. For this reason, in order to obtain a high-quality radiographic image, an offset image acquisition process is usually performed before or after a radiographic image acquisition process in which data on the offset due to the dark charge (hereinafter referred to as an "offset image") is read from each radiation detection element without irradiating radiation, in which charges generated by irradiation of radiation are accumulated in each radiation detection element and then read out to obtain a radiographic image (also referred to as a "photographed image"). Then, an offset correction is performed in which the offset due to the dark charge is removed from the radiographic image (photographed image) by subtracting the offset image from the radiographic image (photographed image) obtained by the radiographic image acquisition process.

For example, Patent Document 3 describes a method in which an average of multiple offset images (multiple offset outputs) is stored in advance in a storage unit, and this offset image (offset output value) is used for offset correction.

JP 2017-018705 A International Publication No. 2017/013896 JP 2005-287773 A

However, in order to perform appropriate offset correction, it is preferable to use an offset image that is acquired as close as possible to the time immediately before capturing (mainly capturing) a radiation image (photographed image), i.e., immediately before the start of exposure by the radiation generating device.
As described in Patent Document 3, when using an offset image that has been stored in advance, it is not possible to perform appropriate offset correction on the radiation image (captured image), and there is a risk that the image quality of the captured image will deteriorate.

In addition, in cases where the radiation image capturing device and the radiation generating device cannot operate in sync as described in Patent Documents 1 and 2, the timing of the start of exposure is unknown, making it impossible to distinguish the frame immediately before exposure, and making it difficult to obtain an appropriate offset image. In this regard, Patent Documents 1 and 2 make no mention of obtaining an offset image and performing offset correction.

The object of the present invention is to provide a radiographic imaging device, a radiographic imaging system, a control device, and a program that are capable of capturing high-quality images at low cost even when the radiographic imaging device and the radiation generating device cannot be synchronized.

In order to solve the above problems, the radiation image capturing apparatus of the present invention as set forth in claim 1 comprises:
A radiographic imaging device having a plurality of radiation detection elements that are two-dimensionally arranged corresponding to each pixel of an image and generate electric charges, and generating an image by reading out a signal value of each pixel based on the electric charges respectively generated by the plurality of radiation detection elements,
a setting means for setting either a still image shooting mode in which the images are generated one by one, or a continuous image shooting mode in which the images are generated continuously by repeating the accumulation and readout operations of the electric charges at a predetermined time interval;
a photographing mode determining means for determining whether or not the photographing mode set by the setting means is executable based on at least one of a battery remaining amount and a memory remaining amount;
a control means for executing a photographing operation according to the photographing mode determined to be executable by the photographing mode determination means ;
A detection means for detecting the presence or absence of radiation exposure;
a correction information storage means for storing one or more images acquired before the detection means detects the radiation exposure as an offset image to be used for offset correction;
The present invention is characterized by comprising:

Further, the radiation image capturing system according to claim 9 is
A radiation image capturing system comprising: a radiation image capturing device having a plurality of radiation detection elements which are two-dimensionally arranged corresponding to each pixel of an image and generate electric charges, and which generates an image by reading out a signal value of each pixel based on the electric charges respectively generated by the plurality of radiation detection elements; and a console;
a setting means for setting either a still image shooting mode in which the images are generated one by one, or a continuous image shooting mode in which the images are generated continuously by repeating the accumulation and readout operations of the electric charges at a predetermined time interval;
a photographing mode determining means for determining whether or not the photographing mode set by the setting means is executable based on at least one of a battery remaining amount and a memory remaining amount;
a control means for executing a photographing operation according to the photographing mode determined to be executable by the photographing mode determination means ;
A detection means for detecting the presence or absence of radiation exposure;
a correction information storage means for storing one or more images acquired before the detection means detects the radiation exposure as an offset image to be used for offset correction;
a captured image storage means for storing, as a captured image, an image acquired at a timing after the detection means detects the exposure to radiation;
an image correction means for performing offset correction on the captured image stored in the captured image storage means by using the offset image stored in the correction information storage means;
The present invention is characterized by comprising:

Further, the radiation image capturing system according to claim 14 is
A radiation image capturing system comprising: a radiation image capturing device which includes a plurality of radiation detection elements which are two-dimensionally arranged corresponding to each pixel of an image and generate electric charges, and which generates an image by reading out a signal value of each pixel based on the electric charges respectively generated by the plurality of radiation detection elements; a console; and a radiation generation device which irradiates radiation toward the radiation image capturing device,
a setting means for setting either a still image shooting mode in which the images are generated one by one, or a continuous image shooting mode in which the images are generated continuously by repeating the accumulation and readout operations of the electric charges at a predetermined time interval;
a photographing mode determining means for determining whether or not the photographing mode set by the setting means is executable based on at least one of a battery remaining amount and a memory remaining amount;
a control means for executing a photographing operation according to the photographing mode determined to be executable by the photographing mode determination means ;
A detection means for detecting the presence or absence of radiation exposure;
a correction information storage means for storing one or more images acquired before the detection means detects the radiation exposure as an offset image to be used for offset correction;
a captured image storage means for storing, as a captured image, an image acquired at a timing after the detection means detects the exposure to radiation;
an image correction means for performing offset correction on the captured image stored in the captured image storage means by using the offset image stored in the correction information storage means;
The present invention is characterized by comprising:

The control device according to claim 15 further comprises:
an image storage means for storing images acquired by using the radiation image capturing device;
a detection information storage means for storing detection information of the start of radiation exposure when irradiation of radiation to the radiation image capturing device is started;
a discrimination means for discriminating whether the image is an offset image acquired before the exposure to radiation is detected or a captured image acquired after the exposure to radiation is detected, based on the detection information stored in the detection information storage means;
an image correction unit that performs offset correction on the captured image by using the offset image;
a photographing mode determination means for determining whether or not a selected photographing mode can be implemented based on at least one of a battery remaining amount and a memory remaining amount, when either a still image photographing mode in which the images are generated one by one or a continuous photographing mode in which the images are generated continuously by repeating an accumulation operation and a readout operation of electric charges at a predetermined time interval can be set;
The present invention is characterized by comprising:

The program according to claim 16 further comprises:
On the computer,
an image storage function for storing images acquired using the radiation image capturing device;
a detection information storage function for storing detection information of the start of radiation exposure when irradiation of radiation to the radiation image capturing device is started;
a discrimination function that discriminates, based on the detection information stored by the detection information storage function, whether the image is an offset image acquired before the exposure to radiation is detected or a captured image acquired after the exposure to radiation is detected;
an image correction function that performs offset correction on the captured image by using the offset image;
a photographing mode determination function that, when either a still image photographing mode in which the images are generated one by one, or a continuous photographing mode in which the images are generated continuously by repeating charge accumulation and readout operations at a predetermined time interval, determines whether or not the selected photographing mode is executable based on at least one of a battery remaining amount and a memory remaining amount;
The present invention is characterized by realizing the above.

According to the present invention, even if the radiographic imaging device and the radiation generating device cannot be synchronized, it is possible to perform high-quality imaging at low cost.

1 is a schematic diagram showing the overall configuration of a main part of a radiation image capturing system according to an embodiment of the present invention; FIG. 2 is a block diagram showing an equivalent circuit of the radiation image capturing apparatus. 3 is a flowchart showing the overall procedure of a radiographic image capturing method according to the present embodiment. 4 is a flowchart showing a processing procedure in a continuous shooting mode in FIG. 3 . 5 is an explanatory diagram illustrating a relationship between radiation irradiation timing and image acquisition timing in a continuous imaging mode in the present embodiment. FIG. 13 is an explanatory diagram illustrating a case where the start of exposure is detected during a readout operation. FIG. 13 is an explanatory diagram showing a schematic diagram of how an image is handled when the start of exposure is detected during a readout operation. FIG. 13 is an explanatory diagram illustrating a schematic diagram of a case where the start of exposure is detected during charge accumulation. FIG. 13 is a flowchart showing an example of a procedure for detecting the end of exposure. 13 is an explanatory diagram illustrating a case where the end of exposure is detected during a readout operation. FIG. 13 is an explanatory diagram illustrating a schematic diagram of a case where the end of exposure is detected during charge accumulation. FIG. 1 is a graph showing an example of a change in radiation output intensity along a time axis. 5 is a flowchart showing an example of a procedure for output fluctuation correction. 4 is a flowchart showing a processing procedure in a still image shooting mode in FIG. 3 . 10 is a flowchart showing a processing procedure when performing imaging in a continuous imaging mode in cooperation with a radiation generation device with which communication is possible. 13 is a flowchart showing a processing procedure when imaging in a pulse imaging mode in cooperation with a radiation generation device with which communication is possible; 10 is a flowchart showing a processing procedure when performing imaging in a still image imaging mode in cooperation with a radiation generation device with which communication is possible. FIG. 11 is a block diagram showing a configuration of a main part of a console according to a modified example of the present embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a radiographic image capturing apparatus, a radiographic image capturing system, a control apparatus, and a program according to the present invention will be described with reference to FIGS.
However, although the embodiments described below are subject to various limitations that are technically preferable for implementing the present invention, the technical scope of the present invention is not limited to the following embodiments and illustrated examples.

[Configuration of Radiation Imaging System]
First, a schematic configuration of a radiation image capturing system 100 according to the present embodiment will be described.

As shown in FIG. 1, the radiation image capturing system 100 of this embodiment includes a console 50 and a radiation generating device 60 in addition to the radiation image capturing device 1 .
The radiographic image capturing apparatus 1 and the console 50 are capable of communicating with each other wirelessly or wiredly via various communication networks.
In this embodiment, an example will be described in which the radiographic image capturing device 1 can perform operations from obtaining a radiographic image (hereinafter also referred to as a "captured image") to correcting the captured image by itself.

The radiation image capturing system 100 is composed of a radiation image capturing device 1 and a console 50, and may be used in combination with a radiation generating device outside the system, and may be capable of being connected to a Hospital Information System (HIS), a Radiology Information System (RIS), a Picture Archiving and Communication System (PACS), an image analysis device, etc. (not shown).

[Radiation Generator]
The radiation generating device 60, although not shown in the figure, includes a generator that applies a voltage according to preset radiation irradiation conditions (tube voltage, tube current, irradiation time (mAs value), etc.) based on the operation of an irradiation instruction switch, and a radiation source 61 that generates a dose of radiation (e.g., X-rays) according to the applied voltage when a voltage is applied from the generator.
As shown in Figure 1, the radiation generating device 60 is arranged opposite the radiation image capturing device 1 across the subject M, and is configured to generate radiation in a manner corresponding to the radiation image (still image/dynamic image) to be captured, and irradiate the radiation to the radiation image capturing device 1.

In this embodiment, in addition to capturing general still images, video images can also be captured, and the radiation generating device 60 used is one that is compatible with these.
When performing video imaging, there is a method of irradiating radiation in pulses, but radiation generating devices capable of pulse irradiation are not widely available in imaging facilities, and even if pulse irradiation is possible, there may be variations in the pulse output. Devices capable of outputting neatly aligned pulses are expensive, and if the radiation generating device 60 is limited to such devices, video imaging cannot be performed flexibly.

Therefore, in this embodiment, the present invention is not limited to devices that can handle pulse irradiation, and any device that can set the shooting time (radiation irradiation time) to approximately 1 second or more can be used as the radiation generating device 60. In other words, even if the radiation generating device is a general still image capturing device, if the shooting time is set to approximately 1 second or more, it is possible to capture moving images by regarding this as continuous irradiation.
In addition, the radiation generating device 60 may be installed in an imaging room (not shown), or may be a portable type, such as one mounted on a so-called medical examination vehicle or the like together with the radiation image capturing device 1 and the console 60, etc., and configured to be movable.

〔console〕
The console 60 is used to set various shooting conditions (tube voltage, tube current, exposure time (mAs value), frame rate, subject's physique, presence or absence of a grid, etc.) in the radiation generating device 60 and the radiographic imaging device 1 based on shooting order information obtained from other systems (HIS, RIS, etc.) and user operations, and to perform predetermined image processing on images generated by the radiographic imaging device 1, and is composed of a PC, a dedicated device, etc.

[Radiation image capturing device]
The radiation image capturing device 1, as shown in FIG. 1, for example, is configured in a panel shape with a housing, and is used by being mounted in a holder or the like of a support stand 1a.
The configuration of the radiographic imaging device 1 is not particularly limited. For example, the radiographic imaging device 1 may be formed integrally with a support base 1a or the like, or may be configured as a portable type and be detachable from a holder of various support bases. Alternatively, the radiographic imaging device 1 may be used for imaging by being placed on the body of a patient, who is a subject, as a stand-alone device without being loaded into a holder or the like, or by being inserted between the patient lying on a bed and the bed.

The radiographic imaging device 1 has a plurality of radiation detection elements 7 (see FIG. 2 ) that are arranged two-dimensionally corresponding to each pixel of the image and generate electric charges, and generates an image by reading out the signal value of each pixel based on the charges generated by each of the plurality of radiation detection elements 7.
When radiation is irradiated from the aforementioned radiation generating device 60, the radiographic imaging device 1 generates electric charges in the multiple radiation detection elements 7 in accordance with the received radiation, and generates a radiographic image (photographed image) by reading out the signal values of each pixel based on these electric charges.
Furthermore, in the radiation image capturing device 1, even in a state where radiation is not being irradiated, electric charges (dark charges) are generated in each radiation detection element 7 due to thermal excitation caused by the heat of the radiation detection element 7. Data obtained by reading out from each radiation detection element 7 the dark charges accumulated in the radiation detection element 7 in a state where radiation is not being irradiated becomes offset data (hereinafter referred to as an "offset image") used for offset correction, which will be described later.

Here, a specific configuration of the radiation image capturing device 1 of this embodiment will be described with reference to FIG.
2, the radiation image capturing device 1 includes a detection section P in which a plurality of radiation detection elements 7 are arranged two-dimensionally (in a matrix). A bias line 9 is connected to each radiation detection element 7, and a reverse bias voltage is applied from a bias power supply 14 via the bias line 9 and the connections 10 therebetween.

A thin film transistor (TFT) 8 is connected to each radiation detection element 7 as a switching element, and the TFT 8 is connected to a signal line 6. Each radiation detection element 7 generates an electric charge in accordance with the dose of radiation irradiated through a subject M (not shown).

In addition, in the scanning drive means 15, the on voltage and off voltage supplied from the power supply circuit 15a via the wiring 15c are switched by the gate driver 15b and applied to each line L1 to Lx of the scanning line 5. When an off voltage is applied via the scanning line 5, each TFT 8 turns off, cutting off the electrical connection between the radiation detection element 7 and the signal line 6 and allowing charge to accumulate in the radiation detection element 7. When an on voltage is applied via the scanning line 5, each TFT 8 turns on, releasing the charge accumulated in the radiation detection element 7 to the signal line 6.

Each signal line 6 is connected to a corresponding readout circuit 17 in the readout IC 16. During the readout process of the signal value D, an on-voltage is sequentially applied from the gate driver 15b to each line L1 to Lx of the scanning line 5. When the TFT 8 is turned on, charge flows from the radiation detection element 7 through the TFT 8 and the signal line 6 into the readout circuit 17, and the amplifier circuit 18 outputs a voltage value according to the amount of charge that has flowed in.

A correlated double sampling circuit (denoted as "CDS" in FIG. 2) 19 reads out and outputs the voltage value output from the amplifier circuit 18 as an analog signal value D. The output signal values D are sequentially transmitted to an A/D converter 20 via an analog multiplexer 21, sequentially converted by the A/D converter 20 into digital signal values D, and sequentially stored in a memory means 23.
Incidentally, even when electric charges (dark charges) are generated in each radiation detection element 7 due to thermal excitation or the like, the signal values are read out by a similar process.

The control means 22 is composed of a computer with a central processing unit (CPU), read only memory (ROM), random access memory (RAM), input/output interface, etc. connected to a bus (not shown), a field programmable gate array (FPGA), etc. It may also be composed of a dedicated control circuit.

In this embodiment, the control unit 22 of the radiographic imaging device 1 functions as a control unit that performs imaging operations corresponding to at least a continuous imaging mode. In the continuous imaging mode, images are generated continuously by repeating charge accumulation and readout operations at a predetermined time interval.
In addition, the control means 22 functions as a detection means for detecting the presence or absence of radiation exposure by the radiation generation device 60, and an image correction means for performing offset correction, etc., on the captured image using an offset image.
Furthermore, in this embodiment, the control means 22 can implement a still image shooting mode in which images are generated one by one in addition to the continuous shooting mode, and the control means 22 also functions as a shooting mode determination means for determining an available shooting mode in light of various conditions, such as the remaining battery power of the built-in power source 24 and the remaining memory capacity of the storage means 23.

The conditions considered by the control means 22 are not limited to these. For example, in the case where there is an agreement that continuous shooting is not permitted with the radiographic imaging device 1 unless a specific license is granted, if the facility performing shooting has not acquired the license (the control means 22 cannot confirm the license information), the control means 22 may determine that only the still image shooting mode is possible (the continuous shooting mode cannot be implemented). In addition, in the case of the continuous shooting mode, a lag is likely to remain due to the exposure to radiation of continuous irradiation. For this reason, if the shooting interval is shorter than a specific interval, the control means 22 may determine that the next continuous shooting cannot be performed yet. Furthermore, in the case where image data is finally transmitted from the radiographic imaging device 1 to an external device such as the console 50, the control means 22 may determine the communication state and determine whether or not the continuous shooting mode can be implemented based on whether or not the relatively large amount of image data obtained by the continuous shooting mode is in a state where it is possible to transmit.
Each of these functions of the control means 22 in this embodiment will be described in detail later.

As described above, the control means 22 controls the application of a reverse bias voltage from the bias power supply 14 to each radiation detection element 7, controls the operation of the scan drive means 15 and the readout circuit 17, etc., to perform a readout process of the signal value D from each radiation detection element 7, stores the readout signal value D in the memory means 23, or transfers the stored signal value D to the outside via the communication unit 30, thereby controlling each part of the radiation image capturing device 1.

The control means 22 is also capable of controlling the on/off of the power supply of the radiation image capturing device 1. The control means 22 includes a microcomputer (not shown) that operates with very small power supplied from the built-in power supply 24 even when the power supply of the radiation image capturing device 1 is off, and the control means 22 is configured to be able to control the switching of the power supply of the radiation image capturing device 1 from off to on even when the power supply of the radiation image capturing device 1 is off.

The control means 22 is also connected to a storage means 23 configured with a static RAM (SRAM), a synchronous DRAM (SDRAM), a NAND type flash memory, or the like.
The memory means 23 in this embodiment functions as a correction information memory means that stores an image acquired before the control means 22 as a detection means detects radiation exposure as an offset image to be used for offset correction, and as a captured image memory means that stores an image acquired after the control means 22 as a detection means detects radiation exposure as a captured image.
In addition, when the control means 22 as a detection means detects whether or not radiation has been exposed, the memory means 23 also functions as a detection information memory means for retaining detection information of the start of radiation exposure, such as when radiation irradiation by the radiation generating device 6 has begun on the radiation image capturing device 1.
The items stored in the storage means 23 are not limited to those exemplified here. A part of these items may be stored, or items other than these items may be stored.

The control means 22 is further connected to an internal power source (battery) 24, which is composed of a lithium ion capacitor or the like. The control means 22 is further connected to a communication unit 30 for communicating with the outside world wirelessly or wired via an antenna 29 and a connector 27.

In addition, an operation means 31, a notification means 32, etc. are connected to the control means 22 of this embodiment. Incidentally, the provision of the operation means 31 and the notification means 32 is not an essential configuration.
The operation means 31 is composed of various switches, such as a power switch and a mode setting switch as a setting means for selecting and setting a shooting mode.
The operation means 31 may be a button or a switch provided on the surface or side of the housing of the radiological image capturing device 1, or may be a touch panel if the device is equipped with a display unit having a touch panel.
The operation means 31 as a setting means can set either a continuous shooting mode or a still image shooting mode, and when either shooting mode is set by the operation means 31 as a setting means, the control means 22 carries out a shooting operation according to the shooting mode set by the setting means.

The notification means 32 is composed of, for example, a display means, a sound output means including a speaker, etc., a vibration generating means including a vibration motor, etc. At least one type of notification means 32 may be provided, or a combination of multiple types may be used.
When a display means is provided as the notification means 32, a display unit, indicator, lamp, etc., configured by a monitor that displays images such as an LCD (Liquid Crystal Display) or CRT (Cathode Ray Tube) (not shown) is provided on the surface or side of the housing.

The notification means 32 in this embodiment functions as a first notification means for notifying the operating state related to shooting, and as a second notification means for notifying the result of the judgment made by the control means 22 as a shooting mode judgment means. The first notification means and the second notification means may be the same, or may be provided separately. For example, a lamp or indicator may be provided as the first notification means, and a lamp or indicator may be provided as the second notification means separately. Furthermore, the first notification means may be configured with a lamp or indicator, and the second notification means may be configured with a display unit equipped with an LCD, CRT, or the like.

The operating status related to shooting includes, for example, various states such as preparing for shooting, shooting, and transferring data (e.g., data of the captured image), and the user is notified of the status of the radiation image shooting device 1 by displaying a display or turning on a lamp, etc.
The shooting mode determination result is, for example, whether both still image shooting mode and video shooting mode are possible, only still image shooting mode is possible, or neither shooting mode is possible, and the user is notified of the shooting modes that can be implemented by displaying them, etc.
If there is a shooting mode that cannot be implemented, the reason why the mode cannot be implemented (for example, insufficient battery power, insufficient memory power, etc.) may also be notified (for example, displayed on the display unit) by the notification means 32. It is preferable that the reason why the mode cannot be implemented is displayed by an easy-to-understand icon or the like so that the user can understand it at a glance.

[Operation of Radiation Imaging Apparatus]
Next, the operation of the radiation image capturing apparatus 1 (radiation image capturing system 100 including the radiation image capturing apparatus 1) in this embodiment will be described.

First, as shown in FIG. 3, the operation means 31 as a setting means is operated to set the radiographic imaging device 1 to either the continuous imaging mode or the still image imaging mode (step S1).
The control means 22 judges whether the set photographing mode is the continuous photographing mode (step S2). If the continuous photographing mode is set (step S2; YES), it judges whether the set photographing mode (i.e., the continuous photographing mode) can be implemented in light of various conditions such as the remaining battery level (step S3).

When it is determined that the continuous shooting mode is executable (step S3; YES), the control means 22 controls each section to perform a shooting operation in the continuous shooting mode (step S4).
On the other hand, if it is determined that the continuous shooting mode cannot be implemented (step S3; NO), the control means 22 notifies the user that the continuous shooting mode cannot be implemented and the reason for this by the notification means 32 as the second notification means (step S5).

On the other hand, even if the continuous shooting mode is not set (i.e., if the still image shooting mode is set, step S2: NO), it is determined whether or not the set shooting mode (i.e., the still image shooting mode) can be implemented in light of various conditions such as the remaining battery level (step S6). If it is determined that the still image shooting mode can be implemented (step S6: YES), the control means 22 controls each section to implement a shooting operation in the still image shooting mode (step S7).
On the other hand, if it is determined that the still image shooting mode cannot be implemented (step S6; NO), the control means 22 notifies the user that the still image shooting mode cannot be implemented and the reason for this via the notification means 32 as the second notification means (step S8).

In addition, when any of the shooting modes is set, the notification means 32 may notify the user of the current operating status in the set shooting mode as a first notification means for notifying the operating status related to shooting.
The operating state is, for example, each state of being prepared for imaging, being able to image, being imaged, being transferred image data, etc. Here, being prepared for imaging means, for example, when it is set to acquire 16 offset images in the continuous exposure mode, the actual imaging (imaging by irradiating radiation to acquire an image) cannot be performed while the offset images are being acquired, and this time is the period during which imaging is being prepared.
The manner in which the operating status is notified is not particularly limited, but for example, when preparation is being made to acquire offset images, the color of the lit part of the indicator may change or the blinking state may change as a predetermined number of offset images are acquired.
The first notification means may be the same as the second notification means, or they may be provided separately.
By notifying the operating state, it is possible to prevent erroneous photography, such as erroneous exposure during preparation for photography, for example.

FIG. 4 is a flow chart showing a procedure when the continuous imaging mode is performed, and FIG. 5 is an explanatory diagram showing the relationship between the output of radiation from the radiation generating device and the driving of the radiation image capturing device.
When the continuous imaging mode is implemented, a preparatory operation before imaging is performed (step S11) as shown in Fig. 4. Specifically, as the preparatory operation, in the radiation imaging device 1, the detection unit P constituted by the radiation detection element 7 repeatedly accumulates electric charges and reads out signal values based on the accumulated electric charges. Then, the read-out signal values (image signal values) are acquired as an image (step S12).

As shown in FIG. 5, the signal value data stored and read out before radiation exposure is an offset image that is information on dark charges.
The control means 22 judges at any time whether the start of exposure has been detected (step S13), and until the start of exposure is detected (step S13; NO), it updates the offset image to the latest acquired image at any time, stores it in the memory means 23 as a correction information storage means (step S14), and returns to step S12 to repeat the process.
In this embodiment, the control means 22 detects the start of exposure (i.e., the timing when the radiation output changes from OFF to ON in Figure 5), and determines that the image acquired before the start of exposure is an offset image, and the image acquired after the start of exposure is a captured image.

Any method may be used to detect the start of exposure.
For example, a radiation sensor (X-ray sensor) that detects radiation may be mounted inside and outside the radiation image capturing device 1, and the determination may be made based on the output of the radiation sensor. In addition, when performing continuous imaging, the image signal value itself is read out before the start of exposure, so the determination may also be made using the read-out image signal value (pixel value). When the image signal value (pixel value) is used, for example, a certain threshold signal value is set, and it is determined that exposure has started when an image signal value (pixel value) exceeding this threshold is read out.
In this way, by the control means 22 detecting the timing of the start of radiation exposure, it is possible to correctly determine the end of the image before the start of exposure (offset image) and the beginning of the radiation image (photographed image). Therefore, even if the radiation image capturing device 1 and the radiation generating device 60 cannot be synchronized or coordinated, it is possible to obtain an offset image that is acquired as close as possible to the timing at which the photographed image is acquired each time photography (main photography by irradiating radiation) is performed, improving the accuracy of offset correction and improving the image quality of the photographed image.

It is possible to obtain an offset image after the start of exposure, but in this case, the offset image will contain lag components such as afterglow of the image due to radiation that has already been exposed. If correction is performed using an offset image that has been affected by such exposure, the accuracy of the correction will deteriorate. For this reason, it is preferable to obtain an offset image immediately before the start of exposure and before the actual shooting.

The offset image may be stored in the storage means 23 in the radiographic imaging device 1, or in various storage means provided outside the radiographic imaging device 1. For example, the offset image may be transmitted to the console 50 or the like and stored at the transmission destination.
Further, the offset image used for the offset correction may be one or more than one.
For example, as shown in FIG. 5, when there are multiple images acquired before the start of exposure is detected, one of these images that is closest to the timing of the start of exposure may be selected as the offset image, or multiple images (in the example of FIG. 5, three images are acquired by accumulating and reading three sets of images before the start of exposure is detected) may be used as the offset image.
When multiple images are used, the offset image is generated, for example, by averaging the images. Furthermore, the method is not limited to averaging, and one offset image may be generated from multiple images by taking a median for each pixel, calculating a mode, or using a weighted average.
When a plurality of images are used in this manner, random noise can be removed, so that fixed pattern noise can be extracted with high precision, improving the precision of offset correction.

Here, the timing at which the start of radiation exposure is detected and how images on the boundary before and after the start of exposure are handled will be described in detail with reference to FIGS. 6 and 7. FIG.
5, when the start of exposure is detected exactly at the boundary between a set of charge accumulation and readout operations, an image accumulated and readout before the start of exposure can be treated as an offset image, and an image accumulated and readout after the start of exposure can be treated as a captured image. However, the start of exposure is not necessarily detected exactly at the boundary between the sets in this way.
The detection timing is assumed to be during charge accumulation operation or during readout operation.

FIG. 6 is a diagram showing a schematic diagram of a case where the timing at which the start of exposure is detected is during the operation of reading out signal values in the radiation image capturing device 1. In FIG.
In this case, the image (dark image) that is stored and read out before the start of exposure can be treated as an offset image, and the image that is stored and read out after the start of exposure can be treated as a captured image; however, the handling of the image that was in the process of being read out when the start of exposure was detected becomes an issue.
In the example shown in Figure 6, when the start of exposure is detected during the readout operation in the accumulation and readout of the fourth set, the image being readout may be discarded, or may be stored as a captured image if it can be used as a captured image.

For example, when the image signal values are read out sequentially from the top of the image on the panel, if exposure is started during readout, the rows that have already been read out before exposure starts become unexposed images (dark images), and the rows that are read out after exposure starts become exposed images, resulting in a mixture of unexposed and exposed areas within one frame.
In such a case, the image may be discarded.
When such an image is used as a captured image, for example, it is conceivable to combine the exposure area that can be used as the captured image with the next image and use it as a single image.

That is, for example, as shown in FIG. 7, if the start of exposure is detected while the image signal value of the nth row of a frame image N is being read out, the image from the nth row to the final row of that image is saved as the image of frame image N, and when the image signal value of the next frame image N+1 is read out, the image from the nth row to the final row of frame image N is combined with the image from the 1st row to the n-1th row of frame image N+1 to form a single captured image.
In this case, the read start position is shifted so that the nth row becomes the first row to be read out in the subsequent frames.

In addition, if the start of exposure is detected when reading out the image signal value of the nth row, the images from the n+1th row to the final row may be combined with the images from the 1st row to the nth row of the next frame image to construct a single captured image.
In addition, the image from the nth (or n+1)th row to the last row of a frame image N may be averaged with the image from the nth (or n+1)th row to the last row of the next frame image N+1 to obtain frame image N+1, and subsequent frames may be read from the first row without shifting the start position of readout.

In contrast to this, FIG. 8 is a diagram that illustrates a case where the timing at which the start of exposure is detected is during the accumulation of charges in the radiation image capturing device 1. In FIG.
When the start of exposure is detected during accumulation, if it is detected early in the accumulation, a high signal value is read out, and if it is detected late in the accumulation, a significantly low signal value is read out.
Therefore, whether or not such an image is to be discarded is determined, for example, by the signal value of the image. That is, for example, a predetermined threshold is set for the read image signal value, and if the threshold is exceeded, the image is stored as a valid captured image, and if the image signal value is lower than the threshold, the image is discarded. Even if the signal value is low, such an image cannot be used as an offset image because it contains an exposure component, and is discarded unless it is worthy of being treated as a captured image.

Up to this point, we have described the case where accumulation and readout are alternately performed to acquire an image as shown in Figure 5, but when shooting at a high frame rate such as 30 fps, there is no need to provide an accumulation time. That is, in the readout operation, the detection unit P is read out one row at a time starting from the top row, but the switches of rows where readout is not being performed are closed. This is essentially the same as when accumulation is being performed in other rows with closed switches while a row is being read out. For this reason, even if a separate accumulation time is not provided in which all switches are closed, accumulation and readout are repeated for each row. If a separate accumulation time is not provided, the processing time can be shortened, and the frame rate can be increased accordingly.

In the present embodiment, the offset image is updated to the latest one and stored each time an offset image is acquired before the start of exposure, but the offset image is not limited to this.
For example, all data may be stored up to the upper limit of the memory capacity of the storage means 23, and the offset image to be used for offset correction may be determined later based on the detection results after the end of the imaging operation, etc. to determine the timing for starting exposure.
If there is sufficient memory capacity, all images from before the start of exposure to its end can be stored, and after the end of shooting, the acquired images can be distinguished into offset images and shooting images before and after the timing of the start of exposure based on the detection information detected by the control means 22 as a detection means.

Returning to FIG. 4, when the start of exposure is detected (step S13; YES), the control means 22 acquires subsequent images as photographed images (step S15) and stores these in the storage means 23 as photographed image storage means (step S16).
The control means 22 judges from time to time whether the end of exposure has been detected (step S17), and returns to step S15 to repeat the process of acquiring captured images until the end of exposure is detected (step S17; NO).
On the other hand, when it is detected that the exposure has ended (step S17; YES), offset correction is performed on the captured image using the offset image acquired before the start of the exposure (step S18).

FIG. 9 is a flowchart showing the procedure for detecting the end of exposure.
After detecting the start of exposure, as shown in FIG. 9, the control means 22 acquires a photographed image (step S21), and stores the image in the storage means 23 serving as a photographed image storage means (step S22).
Then, in the same manner as in detecting the start of exposure, it is determined that exposure has ended when, for example, the signal value (pixel value) of the read image falls below a predetermined threshold value.
Specifically, an evaluation value is calculated for the acquired image (signal value of the image) (step S23). The evaluation value may be any representative value of the captured image, such as a maximum value, minimum value, average value, median value, mode value, etc.
Then, the control means 22 judges whether or not this evaluation value falls below a predetermined threshold value (step S24).
In addition to the method of calculating the evaluation value from one frame of image data (image signal values), for example, one row of image signal values may be read out to calculate an evaluation value, and the end of exposure may be determined based on this. In addition, if a sensor for detecting the output of radiation is provided, the output of the radiation sensor may be used to make the determination.

If the signal value of the image does not fall below the threshold value (step S24; NO), the counter is reset to "0" (step S25), and the process returns to step S21 and is repeated.
On the other hand, if the signal value of the image falls below the threshold value (step S24; YES), there is a possibility that the exposure has ended, so the control means 22 increments the counter by "+1" (step S26).
In this embodiment, in order to prevent erroneous termination of imaging when the signal value temporarily drops due to some factor (external disturbance effect) even though radiation irradiation is continuing and imaging should continue, a so-called dead time is provided so that exposure is determined to be terminated when the signal value falls below the threshold value for a certain consecutive period of time.
Therefore, when the signal value of the image falls below the threshold value and the counter is incremented, the control means 22 further judges whether or not the counter has exceeded a predetermined dead time (step S27).

If the counter has not exceeded the predetermined dead time (step S27; NO), the process returns to step S21 and is repeated.
On the other hand, if the counter exceeds the specified dead time (step S27; YES), that is, if the signal value of the image is continuously below the threshold for a preset period of time, it is determined that the exposure has ended (step S28), and the images acquired during the dead time are deleted (discarded) (step S29).

It is not essential to detect the end of exposure, and imaging may be ended when a predetermined time has elapsed since the start of exposure, for example.
In the case of this embodiment, when the end of exposure is detected and imaging is terminated, the captured images acquired while radiation was being irradiated can be properly identified, and when the captured images are stored in the memory means 23 or the like or when the captured image data is transmitted to an external device, only the necessary images can be selected, thereby optimizing the amount of transmitted data and the amount of memory storage.
As in the case of end detection, a certain dead time may also be provided in detection of the start of exposure, and exposure may be determined to have started when the threshold value is exceeded for a certain period of time.
The threshold value of the image signal value (pixel value) and the dead time are matters that are appropriately set.

Here, the timing at which the end of radiation exposure is detected and how images on the boundary before and after the end of exposure are handled will be described in detail with reference to FIGS. 10 and 11. FIG.
5, when the end of exposure is detected exactly at the boundary between a set of charge accumulation and readout, the image accumulated and readout before the end of exposure is detected is used as the captured image, and the image after the end of exposure is discarded. However, the end of exposure is not necessarily detected exactly at the boundary between the sets, as is the case when exposure starts.
The timing of detection is assumed to be during charge accumulation (as shown in FIG. 11) or during readout (as shown in FIG. 10). If charge is being accumulated or during readout when the end of exposure is detected, a problem may arise as to whether or not to discard the image.

In this case, the following four patterns are assumed:
First, if the start of exposure is detected during a read operation and the end of exposure is also detected during a read operation, and if the start of exposure is detected when reading out the nth row of a frame and the end of exposure is detected when reading out the mth row, then if n>m, the frame will be a partially unexposed image, a missing image, and so the image that was being read out at the time the end was detected is discarded.
Also, when n≦m, that is, when the timing of starting and ending exposure overlap, the readout images up to the nth row are stored and the remaining portion is discarded.
On the other hand, if the start of exposure is detected when charge is accumulated and the end of exposure is detected during a readout operation, the image at the time of end detection is discarded since it simply represents a few extra rows.

Next, when the end of exposure is detected during charge accumulation, similar to the case of detecting the start of exposure, it is considered that the signal value will differ significantly depending on the timing of charge accumulation at which the end of exposure is detected.
For this reason, it is preferable to set a threshold value for the signal value in advance and determine whether to discard or store an image based on the relationship with the threshold value.

In the case of shooting a moving image, in addition to the offset correction, output fluctuation correction may be applied to the shot image, which is a kind of gain correction in the frame direction (time axis direction).
In the graph shown in FIG. 12, the horizontal axis represents time and the vertical axis represents radiation output intensity.
When radiation is continuously irradiated to capture a moving image, the radiation output intensity may not always be constant during irradiation, as shown in Fig. 12. This depends on the performance, characteristics, etc. of the radiation generating device 60.
In order to eliminate such variations in radiation output intensity, radiation output fluctuation information (dose fluctuation information) is stored in memory means 23 as a correction information storage means, and the control means 22 as an image correction means uses this information to correct the data of the captured image.

The output fluctuation information may be acquired simultaneously during shooting, or if the radiation generating device 60 to be used for shooting has been determined in advance, preliminary shooting may be performed without positioning the subject M before shooting, and the previously stored information may be used.
The output fluctuation information may be obtained using an image signal, or, if a radiation sensor is mounted on the radiation image capturing device 1, an output signal from the sensor may be used. Alternatively, an output signal from a separate radiation sensor may be used that is installed outside the radiation image capturing device 1. Furthermore, the output fluctuation information may be obtained by combining several of these methods.
In addition, if the output fluctuation correction is performed before the offset correction, the output fluctuation correction affects the signal value of the noise before the offset correction, and a deviation occurs when the offset correction is performed after that. Therefore, it is preferable to perform the output fluctuation correction after the offset correction.

FIG. 13 is a flowchart showing a procedure for performing output fluctuation correction.
When performing output fluctuation correction, first, a blank area (i.e., an area where no subject exists) is identified from a photographed image (step S31), as shown in Fig. 13. The blank area may be specified by a user, or the blank area may be determined from the feature amount of the acquired photographed image.
Then, the raw signal value is obtained for all frames of the captured image (step S32), and this signal value is normalized by taking the average of the signal values obtained for all frames (step S33), and each frame of the captured image is divided by the normalized signal value (step S34).

Up to this point, we have described the case where video shooting is performed in the continuous shooting mode, but as shown in FIG. 3 and other figures, in this embodiment, it is also possible to shoot still images in the still image shooting mode.

FIG. 14 is a flowchart showing the procedure when the still image shooting mode is set and a still image is shot in this embodiment.
14, when a still image is captured, a preparation operation before capture (step S41) is performed, and then the TFT gate of the detection unit P in the radiation image capture device 1 is opened to output a signal value, which is then discarded. That is, a reset operation is performed in which the opening and closing of the TFT gate is repeated in a short period of time (step S42).
The control means 22 judges from time to time whether radiation has been irradiated or not (step S43), and if exposure is not detected (step S43; NO), repeats the reset operation of step S42.
On the other hand, if exposure is detected (step S43; YES), the reset operation is stopped and the state transitions to a charge accumulation state, and after accumulating for a predetermined time, the signal value is read out and a photographed image is acquired (step S44). The acquired photographed image (still image) is stored in the storage means 23 as a photographed image storage means (step S45).
The charge accumulation operation in the still image capture mode may be terminated upon a timeout at a predetermined time, or may be continued until the end of exposure is detected, as in the continuous capture mode.

As in the case of continuous imaging, any method may be used to detect exposure, and for example, a radiation sensor for detecting radiation may be provided inside or outside the radiographic image capturing device 1, and the control means 22 may detect exposure by observing the output of the radiation sensor. In addition, in the still image capturing mode, it is possible to detect exposure by various methods described in JP2009-219538A, WO2011/135917A, WO2011/152093A, etc., such as detection from a read-out signal value or using a leak signal.
By detecting exposure in this manner, even if the radiographic imaging device 1 cannot synchronize (communicate) with the radiation generating device 60, the moment radiation is exposed, it is possible to transition from a state in which reset operations are repeated to a charge accumulation state and capture a still image.

Moreover, after the exposure, an offset image is obtained (step S46), and this is stored in the storage means 23 as a correction information storage means (step S47).
Then, the offset image is used to perform offset correction on the captured image (step S48).
The timing for acquiring the offset image does not have to be after exposure, and it can be before exposure. However, in the case of still image shooting, the exposure time is extremely short compared to continuous shooting, and the radiation dose per shooting is small, so that even if the offset image is acquired after exposure, the lag component in the offset image can be ignored.

Although the above description has been given of the case where the radiographic imaging device 1 is used in combination with a radiation generating device 60 with which it cannot synchronize (communicate), in this embodiment, it is assumed that one radiographic imaging device 1 is used in combination with various types of radiation generating devices 60, and it is also possible to use the radiographic imaging device 1 in combination with a radiation generating device 60 with which it can synchronize (communicate) with each other. Note that the present invention is not limited to a case where the radiation generating device 60 and the radiographic imaging device 1 directly communicate with each other, and may be configured so that the radiation generating device 60 and the radiographic imaging device 1 can be synchronized with each other via a console 50 or the like.
In this way, when radiographic imaging device 1 is used in combination with a communicable radiation generating device 60 to capture radiographic images, the radiographic imaging device 1 and the radiation generating device 60 work together in a radiographic imaging system composed of the radiographic imaging device 1 and the radiation generating device 60, or the radiographic imaging device 1 and the radiation generating device 60, and a console 50 that communicates with both of these devices.

FIG. 15 is a flowchart showing the procedure of the continuous imaging mode when the radiation image capturing device is used in combination with a radiation generating device that can be synchronized (communicated) with each other.
As shown in FIG. 15, in this case, after a preparatory operation before shooting (step S51) is performed, an offset image is acquired (step S52), and the offset image is updated with a newly acquired one at any time and stored in the storage means 23 (step S53).
The control means 22 judges from time to time whether or not a ready signal to start irradiation of radiation has been received from outside (step S54), and if a signal to start irradiation has not been received (step S54; NO), the control means 22 returns to step S52 and repeats acquisition of the offset image.
On the other hand, if a signal to start irradiation is received (step S54; YES), irradiation of radiation is permitted (step S55), this point is determined to be the timing to start irradiation, and images acquired after this point are acquired as photographed images (step S56) and stored in the memory means 23 (step S57).

The control means 22 constantly judges whether the irradiation of radiation has been completed (step S58), and if the irradiation has not been completed (step S58; NO), the process returns to step S56 to repeat the acquisition of the photographed images. On the other hand, if the irradiation has been completed (step S58; YES), the acquisition of the photographed images is terminated, and the offset image is used to perform offset correction on the photographed images (step S59).
The timing for performing offset correction is not limited to this, and may be before it is determined that irradiation of radiation has ended.

Furthermore, when the radiation image capturing device 1 is used in combination with a radiation generating device 60 with which it can synchronize (communicate), in addition to the continuous imaging mode and the still image capturing mode, a pulse imaging mode may be selectable. In this case, the operation means 31, which is a setting means for setting the imaging mode, is configured to be able to set the pulse imaging mode in addition to the continuous imaging mode and the still image capturing mode.
In the pulse shooting mode, a pulse generating unit (not shown) that generates a synchronization signal pulse is provided on both the side irradiating radiation (radiation generating device 60) and the side receiving radiation (radiation image capturing device 1), and a synchronization pulse is transmitted from this pulse generating unit to the radiation generating device 60 and the radiation image capturing device 1.
In this case, the radiation image capturing device 1 and the radiation generating device 60 capture moving images by storing and reading charges and irradiating radiation in synchronization with this synchronization pulse.
When the radiographic image capturing apparatus 1 can communicate with the radiation generating apparatus 60 but cannot communicate with the pulse generating unit, the radiographic image capturing apparatus 1 switches to the continuous imaging mode to capture images.

FIG. 16 is a flow chart showing the procedure for performing imaging in the pulse imaging mode.
As shown in FIG. 16, in this case, after a preparatory operation before shooting (step S61), an offset image is acquired (step S62), and the offset image is updated with a newly acquired one at any time and stored in the storage means 23 (step S63).
The control means 22 determines from time to time whether or not it has received a ready signal (synchronization pulse) to start radiation irradiation from outside (step S64), and if it has not received a signal to start irradiation (step S64; NO), it returns to step S62 and repeats acquiring the offset image.
On the other hand, if a signal to start irradiation is received (step S66; YES), irradiation of radiation is permitted (step S65), this point is determined to be the timing to start irradiation, and images acquired after this point are acquired as photographed images (step S66) and stored in the memory means 23 (step S67).

The control means 22 constantly judges whether the irradiation of radiation has been completed (step S68), and if the irradiation has not been completed (step S68; NO), the process returns to step S65 to repeatedly acquire photographed images while permitting the irradiation of radiation. On the other hand, if the irradiation has been completed (step S68; YES), the acquisition of photographed images is terminated, and offset correction is performed on the photographed images using the offset image (step S69).
As in the case of the continuous imaging mode, the offset correction may be performed before it is determined that the radiation irradiation has ended.

When the radiation image capturing apparatus 1 is used in combination with a radiation generation apparatus 60 with which it can synchronize (communicate), when capturing an image in a still image capturing mode, the image capturing is performed, for example, in the procedure shown in FIG.
In this case, similarly to the case shown in FIG. 14, a preparation operation before shooting (step S71) is performed, and then a reset operation is performed (step S72).
The control means 22 judges from time to time whether or not a ready signal for starting irradiation of radiation has been received from outside (step S73), and if a signal for starting irradiation has not been received (step S73; NO), the reset operation of step S72 is repeated.
On the other hand, when a signal to start irradiation is received (step S73; YES), the reset operation is stopped and the state transitions to a charge accumulation state, and after accumulating for a predetermined time, the signal value is read out and a photographed image is acquired (step S74).The acquired photographed image (still image) is stored in the storage means 23 as a photographed image storage means (step S75).
Moreover, after the exposure, an offset image is obtained (step S76), and this is stored in the storage means 23 as a correction information storage means (step S77).
Then, the offset image is used to perform offset correction on the captured image (step S78).

In this way, in the radiographic image capturing apparatus 1 of this embodiment and the radiographic image capturing system 100 including the same, not only when the radiographic image capturing apparatus 1 is used in combination with a radiation generating apparatus 60 with which it can synchronize (communicate), but also when it is used in combination with a radiation generating apparatus 60 with which it cannot communicate, it is possible to properly detect the timing of radiation exposure and obtain an offset image in a state close to the captured image, such as immediately before the start of actual imaging.
Furthermore, the radiation image capturing device 1 can be used for a wide variety of types of imaging, such as continuous imaging and still image imaging.

[effect]
As described above, the radiographic imaging device 1 in this embodiment is a radiographic imaging device 1 that has a plurality of radiation detection elements that are arranged two-dimensionally corresponding to each pixel of an image and generate electric charges, and generates an image by reading out the signal value of each pixel based on the electric charges generated by each of the plurality of radiation detection elements, and is capable of implementing a continuous imaging mode in which images are generated continuously by repeating the accumulation and readout operations of electric charges at predetermined time intervals, and is equipped with a control means 22 that functions as a detection means that detects the presence or absence of radiation exposure, and a storage means 23 that serves as a correction information storage means that stores one or more images acquired at a timing before the control means 22 as detection means detects radiation exposure, as offset images to be used for offset correction.
As a result, even when the radiographic imaging device 1 is used in combination with a radiation generating device 60 with which it cannot synchronize (communicate), it is possible to accurately capture the timing of radiation exposure and obtain an image captured before exposure begins as an offset image.
Therefore, appropriate offset correction can be applied to the captured image regardless of the environment in which the radiation image capturing device 1 is used.

In this embodiment, the control means 22 as a detection means is provided with a memory means 23 as a captured image storage means that stores an image acquired at a timing after the control means 22 as a detection means detects radiation exposure as a captured image, and the control means 22 as an image correction means that performs offset correction on the captured image stored in the memory means 23 by using an offset image.
Therefore, it is possible to perform offset correction on the captured image using an offset image acquired at an appropriate timing.

In this embodiment, output fluctuation information may be stored in the storage means 23 serving as a correction information storage means, and the control means 22 serving as an image correction means may perform output fluctuation correction on the captured image using the output fluctuation information.
In this case, even if there is variation in the output of the radiation generating device 60, a good captured image can be obtained.

In this embodiment, the detection means may also detect the end of radiation exposure. In this case, the image acquired before the detection means detects the end of radiation exposure is regarded as the captured image.
This prevents the image after the end of the exposure from being stored as a captured image, thereby reducing memory capacity. In addition, even when the captured image data is transmitted to an external device, the amount of data transfer can be reduced because unnecessary images are prevented from being transmitted as captured images.

In this embodiment, the image capturing apparatus further includes a notification unit 32 constituted by a display unit or the like as a first notification unit for notifying an operational state relating to photography.
This allows the user to know the operating state of the radiation image capturing device 1, and makes it possible to prevent operational errors and the like.

In this embodiment, the notification means 32 functioning as the first notification means and the second notification means includes at least one of a display means, a sound output means, and a vibration generating means.
This allows the user to easily know the state of the radiation image capturing device 1 and the types of imaging that can be performed.

In this embodiment, the control means 22 can also implement a still image shooting mode in which images are generated one by one, in addition to the continuous shooting mode.
This allows a variety of captured images to be obtained using a single radiation image capturing device 1.

In this embodiment, the camera further includes an operation unit 31 as a setting unit for setting either a continuous shooting mode or a still image shooting mode, and the control unit 22 performs a shooting operation according to the shooting mode set by the setting unit.
This makes it possible to perform a variety of imaging operations using a single radiation image capturing device 1, and to obtain various types of captured images.

In this embodiment, the control unit 22 functions as a photographing mode determination unit that determines an available photographing mode based on at least one of the remaining battery charge and the remaining memory charge,
The result of the determination is notified by the notifying means 32 serving as the second notifying means.
This allows the user to easily know the currently selectable shooting modes.

[Modification]
Although the embodiment of the present invention has been described above, it goes without saying that the present invention is not limited to such an embodiment, and various modifications are possible without departing from the gist of the present invention.

For example, in this embodiment, the control means 22 of the radiation image capturing device 1 in the radiation image capturing system 100 not only controls the basic operation for image acquisition by the radiation image capturing device 1, but also functions as a detection means for detecting whether radiation is being exposed by the radiation generating device 60, an image correction means for performing offset correction using an offset image on the captured image, an imaging mode determination means for determining the available imaging modes, etc., and the example shows a case in which the radiation image capturing device 1 alone can perform everything from capturing the captured image to various correction processes, but the console 50 may also have functions such as a detection means for detecting whether radiation is being exposed by the radiation generating device 60, an image correction means for performing offset correction using an offset image on the captured image, an imaging mode determination means for determining the available imaging modes, etc.

When the console 50 functions as a control device that performs various processes in place of the control means 22 of the radiographic imaging device 1, the console 50 includes an image storage means for storing images acquired using the radiographic imaging device 1, a detection information storage means for retaining detection information of the start of radiation exposure when irradiation of radiation to the radiographic imaging device 1 has begun, a discrimination means for discriminating based on the detection information stored in the detection information storage means whether the image is an offset image acquired at a timing before the radiation exposure was detected or a captured image acquired at a timing after the radiation exposure was detected, and an image correction means for performing offset correction on the captured image using the offset image.
A specific configuration example in this case will be described with reference to FIG.

FIG. 18 is a block diagram showing the main configuration of the console 50. As shown in FIG.
As shown in FIG. 18, the console 50 comprises a control unit 51, a storage unit 52, an operation unit 53, a display unit 54, and a communication unit 55, and each unit is connected by a bus.

The control unit 51 is a control device composed of a CPU (Central Processing Unit), a RAM (Random Access Memory), etc. In response to the operation of the operation unit 53, the CPU of the control unit 51 reads out the system program and various processing programs stored in the memory unit 52, expands them in the RAM, and executes various processes according to the expanded programs.

The storage unit 52 is configured with a non-volatile semiconductor memory, a hard disk, etc. The storage unit 52 stores various programs executed by the control unit 51, parameters required for executing processes by the programs, data such as processing results, etc. The various programs are stored in the form of readable program codes, and the control unit 51 sequentially executes operations in accordance with the program codes.
The storage unit 52 functions, for example, in place of the storage means 23 of the radiographic imaging device 1 described above, or together with the storage means 23, as a correction information storage means for storing offset images and output fluctuation information, a captured image storage means for saving captured images, etc. The storage unit 52 may also function as a detection information storage means for holding detection information of the start of radiation exposure, such as when irradiation of the radiographic imaging device 1 by the radiation generation device 6 has started. The captured images and offset images are transmitted from the radiographic imaging device 1 as appropriate. The output fluctuation information, detection information, etc. may be transmitted from the radiographic imaging device 1, or may be obtained by another external device and sent to the console 50 and stored.

The operation unit 53 is configured with a keyboard equipped with cursor keys, numeric input keys, various function keys, etc., and a pointing device such as a mouse, and outputs instruction signals input by key operations on the keyboard or mouse operations to the control unit 51. The operation unit 53 may also be equipped with a touch panel on the display screen of the display unit 54, and in this case, outputs instruction signals input via the touch panel to the control unit 51.
The operation unit 53 may function as a setting unit that switches the imaging mode of imaging performed by the radiation image capturing device 1 and sets one of the imaging modes.

The display unit 54 is configured with a monitor such as an LCD or a CRT, and displays input instructions and data from the operation unit 53 according to instructions of a display signal input from the control unit 51 .
The display unit 54 may function as a first notification means for notifying the user of the operating status regarding shooting, and as a second notification means for notifying the user of possible shooting modes and, if there are any shooting modes that cannot be implemented, the reasons why those modes cannot be implemented.
Providing such a notification means allows the user to know the operating state of the radiation image capturing device 1 and available capturing modes, etc., and makes it possible to prevent operational errors, etc.
In addition, when the notification means is provided in the console 50, the function of the notification means is not limited to the display unit 54. A lamp or an indicator may be provided as the notification means, or a sound output means such as a speaker may be provided.
The first notification means and the second notification means may be the same or may be provided separately. The notification means may include a display unit 54, a speaker, and the like, and may notify the user by a combination of a plurality of methods such as display and sound.
Furthermore, when a notification means is provided in the console 50, it is not necessary to provide a notification means in the radiographic imaging device 1. Furthermore, both the radiographic imaging device 1 and the console 50 may be provided with notification means, and may be appropriately combined to notify the user of various information.

The communication unit 55 includes a LAN adapter, modem, TA (Terminal Adapter), etc., and controls data transmission and reception between each device connected to the communication network NT.

When the console 50 is configured to function as a control means and control device in this manner, when an image is acquired in the radiation image capturing device 1, it is transferred to the console 50, and the transferred image is stored in the memory unit 52, which serves as an image storage means.
Furthermore, the console 50 acquires detection information of the start of radiation exposure when irradiation of the radiation image capturing device 1 has started, and stores the information in a storage unit 52 as detection information storage means.
Based on the detection information stored in the storage unit 52, which is a detection information storage means, the control unit 51, as a discrimination means, discriminates whether the image is an offset image acquired before the radiation exposure is detected or a captured image acquired after the radiation exposure is detected, and performs offset correction on the captured image using the offset image, as an image correction means. Note that information on various corrections such as output fluctuation correction may also be acquired, and these corrections may be performed by the console 50.

In this way, when the console 50 discriminates whether an image is a photographed image or an offset image, and performs correction processing for various images, the burden on the control means 22 of the radiographic imaging device 1 can be reduced. In addition, by appropriately transferring image data, etc. to the console 50, the memory capacity of the storage means 23 of the radiographic imaging device 1 can be reduced, and imaging can be performed without worrying about memory capacity. In addition, since the capacity of the storage unit 52 of the console 50 is larger than the memory capacity of the storage means 23, there is ample memory capacity, and it is possible to transfer all images obtained by continuous imaging to the console, and then later discriminate whether the image is a photographed image or an offset image, and correct the photographed image, etc., as necessary.
The control means 22 of the radiographic imaging device 1 and the console 50 may share the roles of performing various processes. In this case, the load on the control means 22 and the storage means 23 of the radiographic imaging device 1 can be reduced, and imaging can be performed smoothly.

In addition, the detailed configurations and detailed operations of each part constituting the radiographic imaging device 1 and the radiographic imaging system 100 may be modified as appropriate without departing from the spirit and scope of the present invention.

Reference Signs List 1 Radiation image capturing device 22 Control means 23 Storage means 31 Operation means 32 Notification means 50 Console 51 Control unit 52 Storage unit 53 Operation unit 54 Display unit 60 Radiation generating device 100 Radiation image capturing system

Claims (16)

A radiographic imaging device having a plurality of radiation detection elements that are two-dimensionally arranged corresponding to each pixel of an image and generate electric charges, and generating an image by reading out a signal value of each pixel based on the electric charges respectively generated by the plurality of radiation detection elements,
a setting means for setting either a still image shooting mode in which the images are generated one by one, or a continuous image shooting mode in which the images are generated continuously by repeating the accumulation and readout operations of the electric charges at a predetermined time interval;
a photographing mode determining means for determining whether or not the photographing mode set by the setting means is executable based on at least one of a battery remaining amount and a memory remaining amount;
a control means for executing a photographing operation according to the photographing mode determined to be executable by the photographing mode determination means ;
A detection means for detecting the presence or absence of radiation exposure;
a correction information storage means for storing one or more images acquired before the detection means detects the radiation exposure as an offset image to be used for offset correction;
A radiation image capturing apparatus comprising: a captured image storage means for storing, as a captured image, an image acquired at a timing after the detection means detects the exposure to radiation;
an image correction means for performing offset correction on the captured image stored in the captured image storage means by using the offset image stored in the correction information storage means;
The radiation image capturing apparatus according to claim 1 , further comprising: The correction information storage means further stores output fluctuation information,
3. The radiation image capturing apparatus according to claim 2, wherein the image correction means corrects the captured image using the output fluctuation information stored in the correction information storage means. The detection means also detects the end of radiation exposure,
4. The radiation image capturing device according to claim 1, wherein an image captured before the detection means detects the end of radiation exposure is set as a captured image. The radiographic imaging device according to any one of claims 1 to 4, further comprising a first notification means for notifying an operating state related to imaging. The radiographic imaging device according to claim 5, characterized in that the first notification means includes at least one of a display means, a sound output means, and a vibration generating means. 2. The radiation image capturing apparatus according to claim 1 , further comprising a second notification unit that notifies a result of the determination made by the imaging mode determination unit. 8. The radiographic image capturing device according to claim 7 , wherein the second notification means includes at least one of a display means, a sound output means, and a vibration generating means. A radiation image capturing system comprising: a radiation image capturing device having a plurality of radiation detection elements which are two-dimensionally arranged corresponding to each pixel of an image and generate electric charges, and which generates an image by reading out a signal value of each pixel based on the electric charges respectively generated by the plurality of radiation detection elements; and a console;
a setting means for setting either a still image shooting mode in which the images are generated one by one, or a continuous image shooting mode in which the images are generated continuously by repeating the accumulation and readout operations of the electric charges at a predetermined time interval;
a photographing mode determining means for determining whether or not the photographing mode set by the setting means is executable based on at least one of a battery remaining amount and a memory remaining amount;
a control means for executing a photographing operation according to the photographing mode determined to be executable by the photographing mode determination means ;
A detection means for detecting the presence or absence of radiation exposure;
a correction information storage means for storing one or more images acquired before the detection means detects the radiation exposure as an offset image to be used for offset correction;
a captured image storage means for storing, as a captured image, an image acquired at a timing after the detection means detects the exposure to radiation;
an image correction means for performing offset correction on the captured image stored in the captured image storage means by using the offset image stored in the correction information storage means;
A radiation image capturing system comprising: 10. The radiation image capturing system according to claim 9 , further comprising a first notification means for notifying an operational state relating to the capturing of images. 11. The radiation image capturing system according to claim 10 , wherein the first notification means includes at least one of a display means, a sound output means, and a vibration generating means. 10. The radiation image capturing system according to claim 9 , further comprising a second notification unit that notifies a result of the determination made by the imaging mode determination unit. 13. The radiation image capturing system according to claim 12 , wherein the second notification means includes at least one of a display means, a sound output means, and a vibration generating means. A radiation image capturing system comprising: a radiation image capturing device which includes a plurality of radiation detection elements which are two-dimensionally arranged corresponding to each pixel of an image and generate electric charges, and which generates an image by reading out a signal value of each pixel based on the electric charges respectively generated by the plurality of radiation detection elements; a console; and a radiation generation device which irradiates radiation toward the radiation image capturing device,
a setting means for setting either a still image shooting mode in which the images are generated one by one, or a continuous shooting mode in which the images are generated continuously by repeating the accumulation and readout operations of the electric charges at a predetermined time interval;
a photographing mode determining means for determining whether or not the photographing mode set by the setting means is executable based on at least one of a battery remaining amount and a memory remaining amount;
a control means for executing a photographing operation according to the photographing mode determined to be executable by the photographing mode determination means ;
A detection means for detecting the presence or absence of radiation exposure;
a correction information storage means for storing one or more images acquired before the detection means detects radiation exposure as an offset image to be used for offset correction;
a captured image storage means for storing, as a captured image, an image acquired at a timing after the detection means detects the exposure to radiation;
an image correction means for performing offset correction on the captured image stored in the captured image storage means by using the offset image stored in the correction information storage means;
A radiation image capturing system comprising: an image storage means for storing images acquired by using the radiation image capturing device;
a detection information storage means for storing detection information of the start of radiation exposure when irradiation of radiation to the radiation image capturing device is started;
a discrimination means for discriminating whether the image is an offset image acquired before the exposure to radiation is detected or a captured image acquired after the exposure to radiation is detected, based on the detection information stored in the detection information storage means;
an image correction unit that performs offset correction on the captured image by using the offset image;
a photographing mode determination means for determining whether or not a selected photographing mode can be implemented based on at least one of a battery remaining amount and a memory remaining amount, when either a still image photographing mode in which the images are generated one by one or a continuous photographing mode in which the images are generated continuously by repeating an accumulation operation and a readout operation of electric charges at a predetermined time interval can be set;
A control device comprising: On the computer,
an image storage function for storing images acquired using the radiation image capturing device;
a detection information storage function for storing detection information of the start of radiation exposure when irradiation of radiation to the radiation image capturing device is started;
a discrimination function that discriminates, based on the detection information stored by the detection information storage function, whether the image is an offset image acquired before the exposure to radiation is detected or a captured image acquired after the exposure to radiation is detected;
an image correction function that performs offset correction on the captured image by using the offset image;
a photographing mode determination function that, when either a still image photographing mode in which the images are generated one by one, or a continuous photographing mode in which the images are generated continuously by repeating charge accumulation and readout operations at a predetermined time interval, determines whether or not the selected photographing mode is executable based on at least one of a battery remaining amount and a memory remaining amount;
A program for realizing the above.

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