JP2012134781A - Defective pixel map generation method, defective pixel map generation system, console, and radioactive ray image photographing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate a defective pixel map enabling correction of a defective pixel generated by a difference in quality of a radioactive ray.SOLUTION: A method includes: a step of changing the quality of a radioactive ray for irradiating a radioactive ray image photographing device 1; a step in which the radioactive ray image photographing device 1 generates map-making image data for generating a defective pixel map for each of the quality of the radioactive ray irradiating the radioactive ray image photographing device 1; and a step of generating a defective pixel map in which the positional information of a defective pixel is registered on the basis of plural kinds of map-making image data corresponding to the quality of the radioactive ray irradiating the radioactive ray image photographing device 1.

Description

  The present invention relates to a defective pixel map creation method, a defective pixel map creation system, a console, and a radiographic image capturing apparatus.

  For the purpose of disease diagnosis and the like, radiographic images taken using radiation typified by X-ray images are widely used. Conventionally, such medical radiographic images have been taken using a screen film. In order to digitize radiographic images, CR (Computed Radiography) devices using stimulable phosphor sheets have been developed recently. Then, a radiation image capturing apparatus has been developed in which irradiated radiation is detected by a radiation detection element arranged in a two-dimensional form and acquired as digital image data.

  As such a radiographic imaging apparatus, a so-called direct type radiographic imaging apparatus that generates a charge in a detection element in accordance with a dose of irradiated radiation such as X-rays and converts it into an electrical signal, or irradiated radiation So-called indirect radiation that is converted into an electric signal by generating electric charges with a photoelectric conversion element such as a photodiode in accordance with the energy of the converted electromagnetic wave Various image photographing apparatuses have been developed. In the present invention, the detection element in the direct type radiographic imaging apparatus and the photoelectric conversion element in the indirect type radiographic imaging apparatus are collectively referred to as a radiation detection element.

  This type of radiographic imaging apparatus generally includes a sensor panel in which a plurality of radiation detection elements are two-dimensionally arranged, and is known as an FPD (Flat Panel Detector). Conventionally, the sensor panel has been integrally formed on the support base (see, for example, Patent Document 1), but recently, a portable radiographic imaging device has been developed in which the sensor panel is housed in a housing and can be carried. (See, for example, Patent Document 2).

  In an FPD type radiographic imaging apparatus, abnormal image data is constantly or with a certain probability, for example, when impurities are mixed into the radiation detection element when the radiation detection element is laminated on the sensor panel. A pixel to be output (hereinafter referred to as “defective pixel”) may occur.

When such a defective pixel exists, an image defect occurs in that portion, and a high-definition image cannot be obtained.
Therefore, usually, before displaying a radiographic image captured by a radiographic image capturing apparatus, simple average interpolation that simply averages the pixel values of normal pixels in the vicinity of the defective pixel, or weighting that averages according to the characteristics of the sensor panel, etc. Defective pixel correction processing such as interpolation of pixel values of defective pixels by a technique such as average interpolation is performed.

In order to perform defective pixel correction processing, it is necessary to create a defective pixel map in which position information of defective pixels is registered in advance. If a pixel that is not a defective pixel is mistakenly determined to be a defective pixel, or a pixel that is a defective pixel is not determined to be a defective pixel, and the defective pixel is not determined correctly, an accurate defective pixel map is created. Therefore, the defective pixel cannot be corrected accurately. If correction of defective pixels is not performed accurately, the image quality of the radiographic image will deteriorate, so when making a diagnosis using such a radiographic image, the lesioned part may be overlooked or the normal part may be regarded as the lesioned part. There is a risk of inconvenience such as misdiagnosis due to misunderstanding.
Therefore, in order to accurately determine the defective pixel, the radiation dose can be changed, and the defective pixel position information can be extracted using the captured image obtained by photographing at each irradiation amount. A processing apparatus has been proposed (see, for example, Patent Document 3).

JP-A-9-73144 JP 7-246199 A Japanese Patent Laid-Open No. 2001-427

  However, some defective pixels cannot extract position information even if the radiation dose is changed. Examples of such defective pixels include defective pixels caused by the influence of foreign matter mixed in the housing when the sensor panel is housed in the housing.

For example, a foreign object that cannot transmit the radiation applied to the radiation image capturing apparatus is mixed in the housing, and the foreign object is in the way and the scintillator under the foreign object (detected in the case of a direct radiation image capturing apparatus) When a sufficient dose of radiation is not incident on the device, the pixel corresponding to the position of the foreign object is a defective pixel.
On the other hand, even if foreign matter is mixed in the housing, the radiation irradiated to the radiographic imaging device can pass through the foreign matter, and when a sufficient dose of radiation is incident on the scintillator below the foreign matter, A pixel corresponding to the position of the foreign object is not a defective pixel.

In other words, when the transmittance of radiation with respect to a foreign substance mixed in the housing changes, a pixel corresponding to the position of the foreign substance may or may not be a defective pixel.
In addition, the transmittance | permeability of the radiation with respect to a foreign material changes according to the radiation quality of a radiation. The quality of the radiation irradiated to the radiographic imaging device depends on the imaging conditions that are changed according to the imaging region and the like, specifically, the tube voltage of the radiation generating device that irradiates the radiographic imaging device. Change. Further, the radiation quality of the radiation irradiated to the radiographic image capturing apparatus also varies depending on the presence or absence of the subject and the body shape of the subject.

Even if a defective pixel due to a foreign substance mixed in the housing occurs, the defective pixel can be corrected by using a defective pixel map in which position information of the defective pixel is registered.
However, the conventional defective pixel map is not created by changing the radiation quality of the radiation irradiated to the radiographic imaging device, but is created by keeping the radiation quality constant without changing the radiation quality. is there. Therefore, due to changes in the tube voltage and the presence or absence of the subject, the radiation quality at the time of defective pixel map creation differs from the radiation quality at the time of actual imaging (at the time of subject imaging), and the pixel corresponding to the position of the foreign object Of these, a pixel that was not determined to be a defective pixel when creating a defective pixel map may become a defective pixel during actual shooting, or a pixel that was determined to be defective when creating a defective pixel map may not be a defective pixel during actual shooting. is there. Therefore, defective pixels generated due to differences in radiation quality may not be corrected even by performing defective pixel correction processing using a defective pixel map created without changing the quality, in such cases, There is a high possibility that an appropriate quality radiographic image cannot be acquired.

  The present invention has been made in view of the above problems, and a defective pixel map creation method capable of creating a defective pixel map capable of correcting a defective pixel caused by a difference in radiation radiation quality, and a difference in radiation radiation quality A defective pixel map creation system capable of creating a defective pixel map capable of correcting defective pixels generated by the above, a console capable of correcting defective pixels caused by radiation quality differences using the defective pixel map, and a radiographic imaging device The purpose is to provide.

In order to solve the above problem, the defective pixel map creating method of the present invention is:
In a defective pixel map creating method for creating a defective pixel map used when correcting defective pixels included in image data of a radiographic image generated by a radiographic imaging device,
A change step of changing the radiation quality of the radiation applied to the radiographic imaging device;
The radiation image capturing apparatus generates map creation image data for creating the defective pixel map for each radiation quality of radiation irradiated to the radiation image capturing apparatus,
A defective pixel map that creates the defective pixel map in which position information of the defective pixels is registered based on a plurality of types of map creation image data corresponding to radiation quality irradiated to the radiographic imaging device Creation steps,
It is characterized by having.

Further, the defective pixel map creating system of the present invention is
A radiographic imaging apparatus that performs radiographic imaging, a radiation generation apparatus that irradiates radiation to the radiographic imaging apparatus, and correction of defective pixels included in image data of the radiographic image generated by the radiographic imaging apparatus In a defective pixel map creation system comprising a defective pixel map creation device that creates a defective pixel map to be used at the time,
The radiation generator is capable of changing the radiation quality of the radiation applied to the radiographic imaging device,
The radiographic image capturing device includes a generating unit that generates map creation image data for creating the defective pixel map for each radiation quality of radiation irradiated to the radiographic image capturing device,
The defect pixel map creation device includes the defect in which position information of the defective pixel is registered based on a plurality of types of map creation image data corresponding to radiation quality irradiated to the radiographic imaging device. A defective pixel map creating means for creating a pixel map is provided.

The console of the present invention
In a console that performs predetermined image processing on image data of a radiographic image generated by the radiographic imaging device,
Storage means for storing the defective pixel map created by the defective pixel map creating device provided in the defective pixel map creating system of the present invention;
Based on the defective pixel map stored in the storage means, defective pixel correction means for performing defective pixel correction processing on the image data of the radiographic image generated by the radiographic imaging device;
It is characterized by providing.

Moreover, the radiographic imaging device of the present invention is
A sensor panel comprising a plurality of radiation detection elements arranged two-dimensionally;
A readout circuit that reads out charges from the radiation detection elements, converts the charges into electrical signals for each of the radiation detection elements, and outputs them as image data;
Storage means for storing the defective pixel map created by the defective pixel map creating device provided in the defective pixel map creating system of the present invention;
Defective pixel correction means for performing defective pixel correction processing on the image data output by the readout circuit based on the defective pixel map stored in the storage means;
It is characterized by providing.

  The defective pixel map created in the defective pixel map creating method and the defective pixel map creating system of the present invention is a defective pixel map created by changing the radiation quality of the radiation irradiated to the radiographic image capturing apparatus. Also registered is positional information of defective pixels generated due to a difference in radiation quality of radiation irradiated to the radiographic imaging apparatus such as defective pixels caused by foreign matters mixed in the housing. Therefore, if defective pixel correction processing is performed using the defective pixel map, defective pixels generated due to a difference in the quality of radiation irradiated to the radiographic imaging apparatus can be corrected. It is possible to obtain a radiographic image with a more appropriate image quality than when performing defective pixel correction processing using a defective pixel map created without changing the radiation quality of the irradiated radiation.

  In addition, according to the console and the radiographic imaging apparatus of the present invention, because the defective pixel correction process is performed using the defective pixel map created by changing the radiation quality of the radiation irradiated to the radiographic imaging apparatus, It is also possible to correct defective pixels generated due to differences in the quality of radiation irradiated to the radiographic imaging apparatus. Therefore, it is possible to obtain a radiographic image with a more appropriate image quality than when performing defective pixel correction processing using a defective pixel map created without changing the radiation quality of radiation applied to the radiographic imaging device. It becomes possible.

It is an external appearance perspective view which shows the radiographic imaging apparatus which concerns on this embodiment. It is sectional drawing which follows the XX line in FIG. It is a top view which shows the structure of the board | substrate of a radiographic imaging apparatus. FIG. 4 is an enlarged view showing a configuration of a radiation detection element, a TFT and the like formed in a small region on the substrate of FIG. 3. It is sectional drawing which follows the YY line in FIG. It is a side view explaining the board | substrate with which COF, a printed circuit board, etc. were attached. It is a block diagram showing the equivalent circuit of a radiographic imaging apparatus. It is a figure which shows the whole structure of the radiographic imaging system which concerns on this embodiment. It is a figure which shows the whole structure of the defective pixel map production system which concerns on this embodiment. It is a flowchart for demonstrating the defective pixel map production method which concerns on this embodiment. FIG. 11A is a diagram for explaining a defective pixel when the tube voltage of the radiation generator is a predetermined first inspection voltage, and FIG. 11B is a diagram illustrating the tube voltage of the radiation generator being a predetermined voltage. It is a figure for demonstrating the defective pixel in case it is the voltage for 2nd inspection.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. However, embodiments to which the present invention is applicable are not limited to this, and the present invention is not limited to the illustrated examples.

[Radiation imaging equipment]
First, the configuration of the radiographic image capturing apparatus according to the present embodiment will be described.
In the following, a scintillator or the like is provided as a radiographic image capturing device, and the irradiated radiation is converted into electromagnetic waves having other wavelengths such as visible light and irradiated, and converted into image data that is an electrical signal by the radiation detection element. The so-called indirect type radiographic imaging apparatus will be described. However, the present invention can also be applied to a so-called direct type radiographic imaging apparatus that directly detects radiation with a radiation detection element without using a scintillator or the like. it can.
Although the case where the radiographic image capturing apparatus is a portable radiographic image capturing apparatus will be described, the present invention is also applicable to a fixed type radiographic image capturing apparatus formed integrally with a support base or the like. Can do.

FIG. 1 is an external perspective view of a radiographic imaging apparatus 1 according to the present embodiment, and FIG. 2 is a cross-sectional view taken along line XX in FIG.
The radiographic image capturing apparatus 1 is a cassette type FPD configured so as to be a so-called flat panel detector (hereinafter referred to as “FPD”). The radiographic image capturing apparatus 1 is used for radiographic image capturing and detects radiation and responds to the dose of the radiation. Image data is generated and acquired.
As shown in FIGS. 1 and 2, the radiographic imaging apparatus 1 is configured by housing a sensor panel SP including a scintillator 3 and a substrate 4 in a housing 2.

The housing 2 is formed of a material such as a carbon plate or plastic that transmits radiation at least on a surface R on which radiation is irradiated (hereinafter referred to as “radiation incident surface R”).
In addition, in FIG.1 and FIG.2, although the case 2 is what is called a lunch box type | mold formed with the frame board 2A and the back board 2B, it is not limited to this, For example, Also, it is possible to adopt a so-called monocoque type in which the housing 2 is integrally formed in a rectangular tube shape.

  As shown in FIG. 1, in the present embodiment, a power switch 36, an indicator 37 composed of an LED, etc., a battery 41 (see FIG. 7 to be described later) are replaced on the side surface of the housing 2. A lid member 38 that can be opened and closed is disposed. Further, in the present embodiment, an antenna device 39 that is a communication unit for wirelessly transferring image data to an external device such as a defective pixel map creation device 101 and a console 58 described later is provided on the side surface of the lid member 38. Embedded. It is also possible to configure the image data to be transferred to an external device in a wired manner. In this case, for example, a connection terminal for connecting by inserting a cable or the like as a communication means is a radiographic image. Provided on the side surface of the photographing apparatus 1 or the like.

As shown in FIG. 2, a sensor panel SP is housed inside the housing 2. The sensor panel SP includes a substrate 4 and a scintillator 3 stacked thereon. On the radiation incident surface R side of the substrate 4 and the scintillator 3, a glass substrate 35 for protecting them is disposed. .
A base 31 is disposed below the substrate 4 through a lead thin plate (not shown), and a printed circuit board 33 on which electronic components 32 and the like are disposed, a buffer member 34, and the like are attached. It has been.

The scintillator 3 is bonded to a detection part P (described later) of the substrate 4. In this embodiment, the scintillator 3 is, for example, a phosphor whose main component is converted into an electromagnetic wave having a wavelength of 300 to 800 nm, that is, an electromagnetic wave centered on visible light and output when receiving radiation. .
Specifically, in the present embodiment, the scintillator 3 grows a phosphor on a support film formed of various polymer materials such as a cellulose acetate film, a polyester film, and a polyethylene terephthalate film, for example, by a vapor deposition method. And is made of a columnar crystal of a phosphor. As the vapor growth method, a vapor deposition method, a sputtering method, or the like is preferably used.

  In the present embodiment, the substrate 4 is formed of a glass substrate, and as shown in FIG. 3, a plurality of scanning lines 5 and a plurality of signal lines are provided on a surface 4 a of the substrate 4 facing the scintillator 3. 6 are arranged so as to cross each other. A radiation detection element 7 is provided in each small region r defined by the plurality of scanning lines 5 and the plurality of signal lines 6 on the surface 4 a of the substrate 4.

  In this way, the entire region in which a plurality of radiation detection elements 7 arranged in a two-dimensional manner are provided in each small region r partitioned by the scanning line 5 and the signal line 6, that is, shown by a one-dot chain line in FIG. The region is the detection unit P of the sensor panel SP.

In the present embodiment, a photodiode is used as the radiation detection element 7, but, for example, a phototransistor or the like can also be used.
Each radiation detection element 7 is connected to a source electrode 8s of a thin film transistor (hereinafter referred to as “TFT”) 8 as a switch element, as shown in FIG. 4 which is an enlarged view of FIG. 3 or FIG. Yes. The drain electrode 8 d of the TFT 8 is connected to the signal line 6.

The TFT 8 is turned on when an on-voltage is applied to the gate electrode 8g from the scanning drive means 15 (described later) via the scanning line 5, and the charge accumulated in the radiation detecting element 7 is transferred to the radiation detecting element 7. 7 to the signal line 6.
The TFT 8 is turned off when an off voltage is applied to the gate electrode 8g via the connected scanning line 5, and the emission of the charge from the radiation detecting element 7 to the signal line 6 is stopped, and the radiation detecting element The electric charges generated in 7 are held and accumulated in the radiation detection element 7.

  Here, the structure of the radiation detection element 7 and the TFT 8 in this embodiment will be briefly described with reference to the cross-sectional view shown in FIG. FIG. 5 is a cross-sectional view taken along line YY in FIG.

  As shown in FIG. 5, a gate electrode 8g of a TFT 8 made of Al, Cr, or the like is formed on the surface 4a of the substrate 4 so as to be integrally laminated with the scanning line 5, and the gate electrode 8g and the surface 4a. The radiation detecting element 7 is disposed above the gate electrode 8g on the gate insulating layer 81 made of silicon nitride (SiNx) or the like laminated on the semiconductor layer 82 made of hydrogenated amorphous silicon (a-Si) or the like. The source electrode 8 s connected to the first electrode 74 and the drain electrode 8 d formed integrally with the signal line 6 are laminated.

  The source electrode 8s and the drain electrode 8d are divided by a first passivation layer 83 made of silicon nitride (SiNx) or the like, and the first passivation layer 83 covers the electrodes 8s and 8d from above. In addition, ohmic contact layers 84a and 84b formed in an n-type by doping hydrogenated amorphous silicon with a group VI element are stacked between the semiconductor layer 82 and the source electrode 8s and the drain electrode 8d, respectively. The TFT 8 is formed as described above.

  In the radiation detection element 7, an auxiliary electrode 72 is formed by laminating Al, Cr or the like on an insulating layer 71 formed integrally with the gate insulating layer 81 on the surface 4 a of the substrate 4. A first electrode 74 made of Al, Cr, Mo or the like is laminated on the auxiliary electrode 72 with an insulating layer 73 formed integrally with the first passivation layer 83 interposed therebetween. The first electrode 74 is connected to the source electrode 8 s of the TFT 8 through the hole H formed in the first passivation layer 83. Note that the auxiliary electrode 72 is not necessarily provided.

  On the first electrode 74, an n layer 75 formed in an n-type by doping a hydrogenated amorphous silicon with a group VI element, an i layer 76 which is a conversion layer formed of hydrogenated amorphous silicon, and a hydrogenated amorphous A p layer 77 formed by doping a group III element into silicon and forming a p-type layer is formed by laminating sequentially from below.

  And at the time of radiographic imaging, the radiation irradiated with respect to the radiographic imaging apparatus 1 injects from the radiation entrance surface R of the housing | casing 2, is converted into electromagnetic waves, such as visible light, with the scintillator 3, and the converted electromagnetic waves are illustrated. When irradiated from above, the electromagnetic wave reaches the i layer 76 of the radiation detection element 7, and electron-hole pairs are generated in the i layer 76. In this way, the radiation detection element 7 converts the electromagnetic waves irradiated from the scintillator 3 into electric charges (electron hole pairs).

  On the p layer 77, a second electrode 78 made of a transparent electrode such as ITO is laminated and formed so that the irradiated electromagnetic wave reaches the i layer 76 and the like. In the present embodiment, the radiation detection element 7 is formed as described above. The order of stacking the p layer 77, the i layer 76, and the n layer 75 may be reversed. In the present embodiment, as the radiation detection element 7, a case where a so-called pin-type radiation detection element formed by sequentially stacking the p layer 77, the i layer 76, and the n layer 75 as described above is described. However, it is not limited to this.

  A bias line 9 for applying a bias voltage to the radiation detection element 7 is connected to the upper surface of the second electrode 78 of the radiation detection element 7 via the second electrode 78. The second electrode 78 of the radiation detection element 7, the bias line 9, the first electrode 74 extended to the TFT 8 side, the first passivation layer 83 of the TFT 8, that is, the upper surface portions of the radiation detection element 7 and the TFT 8 are The upper side is covered with a second passivation layer 79 made of silicon nitride (SiNx) or the like.

  As shown in FIGS. 3 and 4, in this embodiment, the bias lines 9 are respectively connected to the plurality of radiation detection elements 7 arranged in a row, and each bias line 9 is parallel to the signal line 6. It is arranged. Further, as shown in FIG. 3, each bias line 9 is bound to the connection 10 at a position outside the detection portion P of the substrate 4.

  Further, in the present embodiment, the connection lines 10 of the scanning lines 5, the signal lines 6, and the bias lines 9 are respectively connected to input / output terminals (also referred to as pads) 11 provided near the edge of the substrate 4. Yes. As shown in FIG. 6, a COF (Chip On Film) 12 in which a chip such as an IC 12 a is incorporated in each input / output terminal 11 includes an anisotropic conductive adhesive film (Anisotropic Conductive Film) or an anisotropic conductive paste ( It is connected via an anisotropic conductive adhesive material 13 such as Anisotropic Conductive Paste).

  The COF 12 is routed to the back surface 4b side of the substrate 4 and connected to the printed circuit board 33 on the back surface 4b side. Thus, the board | substrate 4 part of sensor panel SP of the radiographic imaging apparatus 1 is formed. In FIG. 6, illustration of the electronic component 32 and the like is omitted.

Here, the circuit configuration of the radiation image capturing apparatus 1 will be described.
FIG. 7 is an equivalent circuit diagram of the sensor panel SP of the radiation image capturing apparatus 1 according to the present embodiment.

A bias line 9 is connected to one electrode (second electrode 78) of each radiation detection element 7, and each bias line 9 is bound to a connection 10 and connected to a bias power supply 14. The bias power supply 14 applies a bias voltage (reverse bias voltage in this embodiment) to each of the second electrodes 78 of the radiation detection elements 7 via the connection 10 and the bias lines 9.
The bias power supply 14 is connected to a control means 22 (described later), and the bias voltage applied from the bias power supply 14 to each radiation detection element 7 is controlled by the control means 22.

  Further, the other electrode (first electrode 74) of each radiation detection element 7 is connected to the source electrode 8s (denoted as S in FIG. 7) of the TFT 8, and the gate electrode 8g ( 7 is denoted by G.) is connected to each line L1 to Lx of the scanning line 5 extending from the gate driver 15b of the scanning driving means 15. Further, the drain electrode 8 d (denoted as D in FIG. 7) of each TFT 8 is connected to each signal line 6.

In the present embodiment, the scanning drive unit 15 uses a power supply circuit 15a for supplying an on-voltage and an off-voltage to the gate driver 15b via the wiring 15c, and a voltage applied to each line L1 to Lx of the scanning line 5 as an on-voltage. A gate driver 15b for switching between the off-voltage and the off-voltage.
The gate driver 15b switches the voltage applied to the gate electrode 8g of the TFT 8 via the lines L1 to Lx of the scanning line 5 between the on voltage and the off voltage, and controls the on state and the off state of each TFT 8. To do.

Each signal line 6 is connected to each readout circuit 17 formed in the readout IC 16.
The read IC 16 includes a read circuit 17 including an amplifier circuit 18 and a correlated double sampling circuit 19, an analog multiplexer 21, an A / D converter 20, and the like.

  For example, in radiographic imaging, radiation is applied to the radiographic imaging apparatus 1 through a subject, and the scintillator 3 converts the radiation into electromagnetic waves of other wavelengths and irradiates the radiation detection element 7 directly therebelow. Then, charges are generated according to the radiation dose (the amount of electromagnetic waves) irradiated by the radiation detection element 7.

In the process of reading charges from each radiation detection element 7, the TFT 8 in which an on-voltage is applied to the gate electrode 8 g from the gate driver 15 b of the scanning drive unit 15 through the lines L 1 to Lx of the scanning line 5 is turned on. Electric charges are emitted from the radiation detection element 7 to the signal line 6.
Then, a voltage value is output from the amplification circuit 18 of the readout circuit 17 in accordance with the amount of electric charge emitted from the radiation detection element 7, and is correlated double-sampled by the correlated double sampling circuit 19 of the readout circuit 17 to be an analog value. Are output to the analog multiplexer 21. The image data sequentially output from the analog multiplexer 21 is sequentially converted into digital image data by the A / D converter 20, output to the storage means 40, and sequentially stored.
That is, the readout circuit 17 reads out the electric charge from the radiation detection element 7, converts the electric charge into an electric signal for each radiation detection element 7, and outputs it as image data.

The control means 22 includes a microcomputer having a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc., an FPGA (Field Programmable Gate Array), and the like.
Note that the ROM and RAM may be provided in the storage unit 40 connected to the control unit 22 instead of the control unit 22. Further, the control means 22 may be constituted by a dedicated control circuit.

In the present embodiment, an antenna device 39, a nonvolatile storage device 40, and a battery 41 that supplies power to each functional unit of the radiographic image capturing device 1 are connected to the control unit 22. A connection terminal 42 for charging the battery 41 by supplying power to the battery 41 from a charging device such as a cradle 55 (see FIG. 8 described later) or the like is attached to the battery 41.
Further, although not shown in FIG. 7, a power switch 36 and an indicator 37 are connected to the control means 22.

The control unit 22 controls the operation of each functional unit of the radiographic image capturing apparatus 1.
Specifically, for example, the control unit 22 controls the bias power supply 14 to control the bias voltage applied to each radiation detection element 7 or controls the scan driving unit 15 to apply a signal readout voltage. Various operations such as switching the scanning line 5 or controlling the readout circuit 17 (specifically, the amplification circuit 18 and the correlated double sampling circuit 19) to read out the image data from each radiation detection element 7 It is comprised so that the process of this may be performed.

[Radiation imaging system]
Next, the configuration of the radiographic image capturing system 50 according to the present embodiment will be described.
The radiographic image capturing system 50 is a system that assumes radiographic image capturing performed in, for example, a hospital or a clinic, and can be employed as a system that captures a medical diagnostic image as a radiographic image, but is not necessarily limited thereto. Not.

FIG. 8 is a diagram illustrating an overall configuration of the radiographic image capturing system 50.
As shown in FIG. 8, the radiographic imaging system 50 includes an imaging room R1 that irradiates radiation and images a subject that is a part of the patient (an imaging target region of the patient), and a radiographer adjacent to the imaging room R1. Are arranged in the front chamber R2 for performing various operations such as control of radiation irradiated to the subject by the operator, and the outside thereof.

  In the radiographing room R1, for example, a Bucky device 51 that can be loaded with the radiographic imaging device 1, and a radiation generation device 52 that includes a radiation source (not shown) including an X-ray tube that generates radiation to irradiate the subject. A base station 54 that includes a wireless antenna 53 and relays communication between the radiographic apparatus 1 and an external device such as the console 58 is provided.

In FIG. 8, when the portable radiographic imaging device 1 is used in a state where it is loaded in the cassette holding part 51a of the bucky device 51, or when it is used in a single state where it is not loaded in the bucky device 51, specifically, The radiographic imaging apparatus 1 is shown in such a case that the patient's hand or the like, which is a subject, is placed on the radiation incident surface R and used on the upper surface side of the bucky apparatus 51B for lying position imaging. May be formed integrally with the bucky device 51 or a support base.
Here, when the portable radiographic image capturing apparatus 1 is used in a state where it is not loaded in the bucky device 51, the portable radiographic image capturing device 1 is disposed on the upper surface side of the bucky device 51B for lying position photographing and is an object on the radiation incident surface R. In addition to placing and using the patient's hand, for example, the patient's hand or the like as a subject is placed on the radiation incident surface R by placing it on the upper surface side of a bed or the like provided in the imaging room R1. Alternatively, for example, the patient can be used by being inserted between a patient's waist or legs lying on the bed and the bed.

Further, in FIG. 8, the radiographic image capturing apparatus 1 and the base station 54 are wirelessly connected so that communication between the radiographic image capturing apparatus 1 and the external device can be performed wirelessly via the base station 54. The radiographic image capturing apparatus 1 and the base station 54 are wired by a LAN (Local Area Network) cable or the like, and communication between the radiographic image capturing apparatus 1 and an external device is performed. It is also possible to configure so that it can be performed in a wired manner via the base station 54.
In FIG. 8, the Bucky device 51 and the base station 54 are connected by wire, and the communication between the radiographic imaging device 1 loaded in the Bucky device 51 and the external device is wired via the base station 54. However, the present invention is not limited to this, and the bucky device 51 and the base station 54 may not be connected by wire.

Further, FIG. 8 shows a case in which one of the standing-up shooting bucky devices 51A and the standing-up shooting shooting device 51B is provided as the bucky device 51 in the shooting room R1. The number and type of the bucky devices 51 provided in the photographing room R1 are not particularly limited.
Further, FIG. 8 shows a case where one radiation generating device 52A associated with the bucky device 51 and one portable radiation generating device 52B are provided as the radiation generating device 52 in the imaging room R1. However, the number and type of radiation generators 52 provided in the imaging room R1 are not particularly limited.

  As shown in FIG. 8, in the present embodiment, when the radiographic image capturing apparatus 1 is inserted into the radiographing room R1, a cassette ID for identifying the radiographic image capturing apparatus 1 from the radiographic image capturing apparatus 1 is shown. And a cradle 55 for notifying the console 58 via the base station 54 is provided. The cradle 55 can be configured to charge the radiographic imaging device 1 or the like.

[Radiation generator]
In the radiographing room R1, a radiation generating device 52 that irradiates the radiographic imaging device 1 with radiation is provided.
In the present embodiment, an operation console 57 of the radiation generating device 52 is provided in the front room R2 adjacent to the imaging room R1, and an operator such as a radiologist is placed on the operation console 57 by the radiation generating device 52. An operation switch 56 is provided for operating when instructing the start of radiation irradiation or the like.

  In addition, the radiation generating device 52 adjusts the radiation irradiation direction so that the radiation image capturing device 1 is appropriately irradiated with radiation by the operator such as a radiologist operating the console 57 or manually. The diaphragm may be adjusted so that the radiation is irradiated within a predetermined region of the radiographic imaging apparatus 1, or the radiation source may be adjusted so that an appropriate dose or an appropriate radiation quality is irradiated. It is configured to be able to.

[console]
As shown in FIG. 8, the console 58 includes a display unit 58a composed of a CRT (Cathode Ray Tube), an LCD (Liquid Crystal Display), etc., a control unit 58b for controlling the operation of each functional unit of the console 58, an HDD, and the like. A storage unit 59 (Hard Disk Drive) or the like, and a communication unit (not shown) for communicating with another device such as the radiation imaging apparatus 1 connected to the base station 54 via a LAN cable or the like, The computer includes an input unit (not shown) including a keyboard and a mouse.

Although FIG. 8 shows a case where the console 58 is provided outside the photographing room R1 and the front room R2, the console 58 may be provided in the front room R2, for example.
8 shows a case where the storage means 59 is connected to the console 58, the storage means 59 may be built in the console 58.

When the communication unit receives the image data of the radiographic image generated by the radiographic image capturing apparatus 1 from the radiographic image capturing apparatus 1 via the base station 54, the control unit 58b of the console 58 decompresses the image data. Predetermined image processing such as offset correction processing, gain correction processing, and defective pixel correction processing is performed to create diagnostic image data.
Then, the control unit 58b of the console 58 displays a radiographic image based on the diagnostic image data on the display unit 58a or displays the diagnostic image data according to an instruction from the input unit or the like operated by the operator. The data is output from a communication unit or the like and transmitted to another device (not shown) such as an imager or a data management server.

  In the present embodiment, the console 58 is configured to perform offset correction processing, gain correction processing, and the like. However, the present invention is not limited to this, and for example, the radiographic imaging device 1 performs the offset correction processing and gain correction. It is also possible to configure to perform processing or the like.

Here, in the present embodiment, the storage unit 59 stores a defective pixel map created by a defective pixel map creation device 101 (described later).
The defective pixel map is a map showing the pixel positions of defective pixels among the pixels corresponding to the plurality of radiation detection elements 7 arranged two-dimensionally on the sensor panel SP, and the control unit 58b of the console 58 performs radiation. This is used when correcting defective pixels included in the image data of the radiation image generated by the image capturing apparatus 1.
That is, the control unit 58b of the console 58 performs defective pixel correction processing on the image data of the radiographic image generated by the radiographic imaging device 1 based on the defective pixel map stored in the storage unit 59. It functions as a correction means.

The sensor panel SP includes a plurality of radiation detection elements 7, and some of these radiation detection elements 7 show abnormal output from the beginning of manufacture. The abnormal output of the radiation detection element 7 is one that does not output any charge despite the radiation irradiation, one that outputs only a constant regardless of changes in the radiation dose, and is output every time a fixed dose of radiation is incident. Are different and do not show the law.
If there is an abnormal radiation detection element 7 showing such an output abnormality, an image defect occurs in the pixel portion corresponding to the radiation detection element 7, and a radiation image with an appropriate image quality cannot be acquired. Therefore, it is necessary to correct the defective pixel caused by the abnormal radiation detection element 7.

Further, if foreign matter such as a metal piece or a scintillator piece is mixed between the sensor panel SP and the radiation incident surface R of the housing 2, the foreign matter becomes an obstacle and the columnar shape of the phosphor constituting the scintillator 3. A sufficient dose of radiation may not be incident on the columnar crystal of the phosphor below the foreign substance in the crystal. In such a case, the radiation detection element 7 directly below the columnar crystal of the phosphor below the foreign substance does not output any charge despite radiation irradiation even if the radiation detection element 7 is normal. In some cases, the output is the same as that in the case of the abnormal output described above, and only a constant output is performed regardless of the change in radiation dose.
For this reason, it is necessary to correct also the defective pixels caused by the foreign matters mixed in the housing 2, specifically, the foreign materials mixed between the sensor panel SP and the radiation incident surface R of the housing 2.

The scintillator 3 is composed of a plurality of phosphor columnar crystals, and each of the phosphor columnar crystals is configured to convert the radiation irradiated to the radiographic imaging apparatus 1 into an electromagnetic wave and irradiate it. Has been. In order to obtain a radiographic image with an appropriate image quality, the luminance of the electromagnetic waves emitted from the phosphor columnar crystals must be within a predetermined allowable range. There are variations from the beginning of manufacture, and electromagnetic waves having a luminance exceeding the upper limit value or electromagnetic waves having a luminance lower than the lower limit value may be irradiated from any of the columnar crystals of the phosphor. In addition, when a scintillator piece is mixed as a foreign substance between the sensor panel SP and the radiation incident surface R of the housing 2, the phosphor constituting the scintillator 3 due to the influence of the luminance of electromagnetic waves emitted from the scintillator piece. In some cases, an electromagnetic wave having a luminance outside the allowable range is irradiated from the columnar crystal of the phosphor in the vicinity of the scintillator piece.
If there is a phosphor columnar crystal that irradiates such an electromagnetic wave having a luminance outside the allowable range in the phosphor columnar crystal constituting the scintillator 3, an image white is displayed on the pixel portion corresponding to the columnar crystal of the phosphor. Flying out or blackout occurs, making it impossible to obtain a radiographic image with an appropriate image quality. For this reason, it is necessary to correct defective pixels caused by the luminance of the electromagnetic waves irradiated from the columnar crystals of the phosphor constituting the scintillator 3.

  In the present embodiment, description will be made assuming that only the position information (position coordinates) of the defective pixel is registered in the defective pixel map. However, the defect pixel map includes both the position information of the defective pixel and the position information of the normal pixel. It may be a registered map.

[Defective pixel map creation system]
Next, the configuration of the defective pixel map creation system 100 according to this embodiment will be described.
The defective pixel map creation system 100 is a system that creates a defective pixel map by determining defective pixels by performing an inspection accompanied by radiation irradiation, for example, at the time of a shipping inspection performed before the radiation imaging apparatus 1 is shipped.

FIG. 9 is a diagram showing an overall configuration of the defective pixel map creation system 100.
As shown in FIG. 9, the defective pixel map creation system 100 irradiates the manufactured radiation image capturing apparatus 1 with radiation and inspects the radiation image capturing apparatus 1 and the inspection room R3. An operator such as an inspector is disposed in an operation room R4 for performing various operations such as control of radiation irradiated to the radiation image capturing apparatus 1 and outside thereof.

  Specifically, as illustrated in FIG. 9, the defective pixel map creation system 100 includes a radiation image capturing device 1 that performs radiation image capturing, a radiation generation device 52 that irradiates radiation to the radiation image capturing device 1, and a radiation image. The apparatus includes a defective pixel map creation device 101 that creates a defective pixel map used when correcting defective pixels included in image data of a radiographic image generated by the imaging apparatus 1.

  In the examination room R3, for example, a Bucky device 51 that can be loaded with the radiation image capturing apparatus 1 and a radiation source (not shown) including an X-ray tube that generates radiation to be irradiated to the radiation image capturing apparatus 1 are provided. A radiation generating device 52 provided, and a repeater 103 that relays communication between the radiation image capturing device 1 loaded in the Bucky device 51 and an external device such as the defective pixel map creating device 101 are provided.

  9 shows a case where the portable radiographic imaging device 1 is inspected in a state where it is loaded in the cassette holding portion 51a of the bucky device 51. However, the present invention is not limited to this. For example, It is also possible to configure the radiographic image capturing apparatus 1 to be inspected in a single state where the radiographic image capturing apparatus 1 is not loaded in the bucky device 51.

In FIG. 9, the Bucky device 51 and the repeater 103 are connected by wire, and the communication between the radiographic imaging device 1 loaded in the Bucky device 51 and the external device is wired via the repeater 103. However, the present invention is not limited to this, and the bucky device 51 and the repeater 103 may not be connected by wire.
In this way, when the Bucky device 51 and the repeater 103 are not connected by wire, for example, the repeater 103 is provided with a wireless antenna, and the radiographic image capturing apparatus 1 and the repeater 103 are connected wirelessly to capture a radiographic image. It is also possible to configure the communication between the apparatus 1 and the external apparatus in a wireless manner via the repeater 103, and connect the radiographic image capturing apparatus 1 and the repeater 103 to a LAN cable or the like. It is also possible to configure such that communication between the radiographic image capturing apparatus 1 and the external apparatus can be performed in a wired manner via the repeater 103.

FIG. 9 shows the case where one bucky device 51A for standing position imaging is provided as the bucky device 51 in the examination room R3, but the bucky device 51 provided in the examination room R3. The number and type of are not particularly limited.
FIG. 9 shows a case where one radiation generating device 52A associated with the bucky device 51 is provided as the radiation generating device 52 in the examination room R3. The number and type of radiation generators 52 provided are not particularly limited.

  The configurations of the radiation generation device 52, the console 57, and the operation switch 56 included in the defective pixel map creation system 100 are the same as the configurations of the radiation generation device 52, the console 57, and the operation switch 56 included in the radiation image capturing system 50 described above. Since they are the same, detailed description is omitted.

[Defective pixel map creation device]
As shown in FIG. 9, the defective pixel map creating apparatus 101 includes a display unit 101a composed of a CRT, an LCD, etc., a control unit 101b that controls the operation of each functional unit of the defective pixel map creating apparatus 101, an HDD, and the like. A communication unit (not shown) for communicating between the storage unit 102 and the repeater 103 connected by a LAN cable or the like and other devices such as the radiographic image capturing apparatus 1 and an input including a keyboard and a mouse A computer (not shown).

FIG. 9 shows the case where the defective pixel map creation device 101 is provided outside the inspection room R3 and the operation room R4. However, the defective pixel map creation device 101 is provided, for example, in the operation room R4. It may be.
9 shows a case where the storage unit 102 is connected to the defective pixel map creation apparatus 101, the storage unit 102 may be built in the defective pixel map creation apparatus 101.

When the communication unit receives image data for map generation generated by the radiographic image capturing apparatus 1 from the radiographic image capturing apparatus 1 via the repeater 103, the control unit 101b of the defective pixel map generating apparatus 101 generates the map. A defective pixel is determined based on the image data for use, and a defective pixel map in which position information of the defective pixel is registered is created.
Then, the control unit 101b of the defective pixel map creation apparatus 101 displays a map image based on the defective pixel map on the display unit 58a or displays the defective pixel map in accordance with an instruction from the input unit or the like operated by the operator. The data is stored in the storage unit 102, or the defective pixel map is output from a communication unit or the like and transmitted to another device (not shown) such as a data management server.

Here, “image data for map creation” is image data of a radiation image generated for creating a defective pixel map. The said radiographic image is image | photographed switching the tube voltage of the radiation generator 52 in the state which does not pass a to-be-photographed object.
That is, the control unit 22 of the radiographic image capturing apparatus 1 functions as a generating unit that generates map creation image data for each radiation quality of the radiation irradiated to the radiographic image capturing apparatus 1.

Then, the control unit 101b of the defective pixel map creation device 101 converts each of a plurality of types of map creation image data corresponding to the radiation quality of the radiation irradiated to the radiation image capturing device 1 into the map creation image data. A map classified by line quality in which position information of included defective pixels is registered is created, and a defective pixel map is created by ORing the created maps classified by line quality.
That is, the control unit 101b of the defective pixel map creating apparatus 101 determines the position information of the defective pixels based on a plurality of types of map creating image data corresponding to the radiation quality of the radiation irradiated to the radiation image capturing apparatus 1. It functions as a defective pixel map creating means for creating a registered defective pixel map.

[Defective pixel map creation method]
Next, the defective pixel map creation method according to the present embodiment will be described with reference to the flowchart of FIG.

  First, an operator such as an inspector operates the console 57 in the operation room R4 or manually sets a predetermined first inspection voltage as the tube voltage of the radiation generator 52 in the inspection room R3. Radiation is emitted from the radiation generator 52 to the radiographic imaging apparatus 1 (step S1).

  In the present embodiment, an operator such as an examiner operates the console 57 or manually sets the tube voltage of the radiation generator 52 (specifically, the radiation source). It is not limited to this. For example, the defective pixel map creating apparatus 101 and the console 57 are connected by wire (or may be wirelessly connected), and an operator such as an inspector operates the input unit of the defective pixel map creating apparatus 101 or the like. The control unit 101b of the defective pixel map creation apparatus 101 can be configured to instruct the control unit 101b to perform control for setting the tube voltage of the radiation generation apparatus 52 via the console 57, or the defective pixel map creation can be performed. The apparatus 101 and the radiation generating apparatus 52 are directly connected, and an operator such as an inspector operates the input unit of the defective pixel map creating apparatus 101 and the like, and the radiation generating apparatus 52 is connected to the control unit 101b of the defective pixel map creating apparatus 101. It is also possible to adopt a configuration instructing to perform control for setting the tube voltage.

  When radiation is emitted from the radiation generator 52 to the radiographic imaging device 1, the control unit 22 of the radiographic imaging device 1 controls each functional unit of the radiographic imaging device 1, and the readout circuit 17 Image data for map generation corresponding to the first inspection voltage is generated by reading out the image data from each radiation detection element 7 (step S2; generation step). Then, the generated map creation image data is transmitted to the defective pixel map creation apparatus 101 via the repeater 103.

  When the map creation image data transmitted from the radiation image capturing apparatus 1 is received, the control unit 101b of the defective pixel map creation apparatus 101 registers the position information of the defective pixels included in the received map creation image data. A map for each line quality is created (step S3; map creation step for each line quality (defective pixel map creation step)).

Specifically, in the present embodiment, the control unit 101b, for example, based on the received map creation image data, the average value (μ) and standard deviation (σ) of the image data from each radiation detection element 7 And calculate. Then, the upper limit threshold for defective pixel determination is set to μ + 5σ and the lower limit threshold is set to μ−5σ, and the value exceeds the upper limit threshold (μ + 5σ) among the image data from each radiation detection element 7. It discriminate | determines image data and the image data in which a value is less than a lower limit threshold value (micro-5 (sigma)). Then, among the pixels corresponding to the plurality of radiation detection elements 7 arranged two-dimensionally on the sensor panel SP, the image data whose value exceeds the upper threshold (μ + 5σ) or the lower threshold (μ-5σ). The pixel corresponding to the radiation detection element 7 that has output image data lower than () is determined as a defective pixel.
Note that the coefficient of the standard deviation (σ) is not limited to “5” and is arbitrary, and the coefficient of the standard deviation (σ) may be arbitrarily set and input.
Also, the upper limit threshold and the lower limit threshold itself may be arbitrarily set and input.

  Next, an operator such as an inspector operates the console 57 in the operation room R4 or manually sets a predetermined second inspection voltage as the tube voltage of the radiation generator 52 in the inspection room R3. Then, the radiation quality of radiation applied to the radiation image capturing apparatus 1 is changed (step S4; change step), and the radiation generating apparatus 52 emits radiation to the radiation image capturing apparatus 1 (step S5).

  When radiation is emitted from the radiation generator 52 to the radiographic imaging device 1, the control unit 22 of the radiographic imaging device 1 controls each functional unit of the radiographic imaging device 1, and the readout circuit 17 Image data for map generation corresponding to the second inspection voltage is generated by reading out the image data from each radiation detection element 7 (step S6; generation step). Then, the generated map creation image data is transmitted to the defective pixel map creation apparatus 101 via the repeater 103.

When the map creation image data transmitted from the radiation image capturing apparatus 1 is received, the control unit 101b of the defective pixel map creation apparatus 101 registers the position information of the defective pixels included in the received map creation image data. A map classified by line quality is created (step S7; map created step by line quality (defective pixel map creating step)).
Note that a map image based on the map according to the line quality created in step S3 or step S7 may be displayed on the display unit 58a of the defective pixel map creation device 101.

Next, the control unit 101b performs a logical sum synthesis of the map classified by line quality created in step S3 and the map classified by line quality created in step S7 to create a defective pixel map (step S8; synthesis step (defective pixel) Map creation step)).
In this way, a defective pixel map is created by the defective pixel map creation device 101 included in the defective pixel map creation system 100.

  In the present embodiment, the defective pixel map is created by performing a logical sum synthesis on the line quality map corresponding to the first inspection voltage and the line quality map corresponding to the second inspection voltage. Therefore, in the defective pixel map, the position information of the pixel that has become a defective pixel both when the tube voltage of the radiation generating device 52 is the first inspection voltage and when the tube voltage is the second inspection voltage, and radiation The position information of the pixel that has become a defective pixel in either the case where the tube voltage of the generator 52 is the first inspection voltage or the case where it is the second inspection voltage is registered as the position information of the defective pixel. ing.

As described above, in addition to the pixels corresponding to the abnormal radiation detection element 7, the pixels corresponding to the position of the foreign matter mixed between the sensor panel SP and the radiation incident surface R of the housing 2 are also defective pixels. Can be.
The pixel corresponding to the position of the foreign matter mixed between the sensor panel SP and the radiation incident surface R of the housing 2 becomes a defective pixel because the radiation irradiated to the radiation imaging apparatus 1 is transmitted through the foreign matter. This is a case where the rate is low and the foreign matter becomes an obstacle, and a sufficient dose of radiation does not enter the columnar crystals of the phosphor below the foreign matter among the phosphor columnar crystals constituting the scintillator 3. Therefore, even if foreign matter is mixed between the sensor panel SP and the radiation incident surface R of the housing 2, the radiation irradiated to the radiation imaging apparatus 1 has a high transmittance with respect to the foreign matter, and the scintillator 3 is configured. When a sufficient dose of radiation is incident on the phosphor columnar crystal below the foreign substance, the pixel corresponding to the position of the foreign substance does not become a defective pixel.

  That is, the radiation quality of the radiation irradiated to the radiographic imaging device 1 changes, and the transmittance of the radiation to the foreign matter mixed between the sensor panel SP and the radiation incident surface R of the housing 2 is changed. When it changes, the pixel corresponding to the position of the foreign substance may become a defective pixel or may not become a defective pixel.

Here, the radiation quality of the radiation irradiated to the radiation image capturing apparatus 1 is changed according to the imaging region or the like, specifically, the radiation generating apparatus 52 that irradiates the radiation image capturing apparatus 1 with radiation. Varies depending on the tube voltage. Further, the radiation quality of the radiation applied to the radiation image capturing apparatus 1 also varies depending on the presence or absence of the subject and the body shape of the subject.
Therefore, for example, when the tube voltage of the radiation generator 52 is changed, a pixel that was a defective pixel may not be a defective pixel, or a pixel that was not a defective pixel may become a defective pixel.
For example, when the subject is changed from a thin person to a thick person, a pixel that is a defective pixel may not be a defective pixel, or a pixel that is not a defective pixel may become a defective pixel.

  Further, even in the case of one foreign matter, when the material and the like are different between a certain portion and the other portion of the one foreign matter, and the radiation transmittance is different between the certain portion and the other portion, the radiographic imaging device 1 If the radiation quality of the irradiated radiation changes, the range of defective pixels may be enlarged or reduced.

Specifically, as shown in FIG. 11, for example, it is assumed that a foreign material M of a different material is mixed between the sensor panel SP and the radiation incident surface R of the housing 2 in the inner portion and the outer portion. . Further, neither the radiation emitted from the radiation generator 52 whose tube voltage is set to 80 kV nor the radiation irradiated from the radiation generator 52 whose tube voltage is set to 50 kV is transmitted to the inner part, The radiation irradiated from the radiation generator 52 with the tube voltage set to 80 kV is sufficiently transmitted to the outer portion, but the radiation irradiated from the radiation generator 52 with the tube voltage set to 50 kV is not transmitted. To do.
In this case, when the radiation image capturing apparatus 1 is irradiated with radiation without passing through the subject, when the tube voltage of the radiation generating apparatus 52 is set to 80 kV, for example, as shown in FIG. In addition, only the pixel corresponding to the position of the inner part (the part surrounded by the one-dot chain line) among the pixels corresponding to the position of the foreign substance M becomes a defective pixel. On the other hand, when the tube voltage of the radiation generator 52 is set to 50 kV, for example, as shown in FIG. 11B, in addition to the pixel corresponding to the position of the inner portion of the foreign matter M, The pixel corresponding to the position of the outer portion (the portion other than the portion surrounded by the one-dot chain line among the portions surrounded by the two-dot chain line) also becomes a defective pixel, and the defective pixel is compared with the case where the tube voltage is 80 kV. The range expands.
In FIGS. 11A and 11B, pixels filled with a polka dot pattern indicate defective pixels.

Even if a defective pixel caused by a foreign substance mixed between the sensor panel SP and the radiation incident surface R of the housing 2 is generated, a defective pixel map in which position information of the defective pixel is registered is displayed. If used, the defective pixel can be corrected.
However, the conventional defective pixel map is not created by changing the radiation quality of the radiation irradiated to the radiation image capturing apparatus 1, but is created by keeping the radiation quality constant without changing the radiation quality. It is. Therefore, due to changes in the tube voltage and the presence or absence of the subject, the radiation quality at the time of defective pixel map creation differs from the radiation quality at the time of actual imaging (at the time of subject imaging), and the pixel corresponding to the position of the foreign object Of these, a pixel that was not a defective pixel when creating a defective pixel map may become a defective pixel during actual shooting, or a pixel that was a defective pixel when creating a defective pixel map may not become a defective pixel during actual shooting. Therefore, defective pixels generated due to differences in radiation quality may not be corrected even by performing defective pixel correction processing using a defective pixel map created without changing the quality, in such cases, There is a high possibility that an appropriate quality radiographic image cannot be acquired.

Further, as described above, among the phosphor columnar crystals constituting the scintillator 3, the pixel corresponding to the position of the phosphor columnar crystal that irradiates electromagnetic waves having a luminance outside the allowable range is also a defective pixel.
The luminance of the electromagnetic wave irradiated from the phosphor columnar crystals constituting the scintillator 3 varies depending on the radiation quality of the radiation irradiated to the radiographic imaging apparatus 1. Therefore, when the tube voltage of the radiation generator 52 is changed, the luminance shifts from outside the allowable range to the allowable range, and the defective pixel is no longer a defective pixel, or the luminance shifts from the allowable range to the outside of the allowable range. Thus, a pixel that was not a defective pixel may become a defective pixel. In addition, when the subject is switched from a thin person to a thick person, the luminance shifts from outside the allowable range to the allowable range and the defective pixel is no longer a defective pixel, or the luminance shifts from the allowable range to the outside allowable range. Thus, a pixel that was not a defective pixel may become a defective pixel.

In this way, defective pixels caused by the luminance of electromagnetic waves irradiated from the columnar crystals of the phosphor constituting the scintillator 3 are also present in the foreign matter mixed between the sensor panel SP and the radiation incident surface R of the housing 2. Similar to the defective pixels that are caused, it occurs due to the difference in the quality of the radiation applied to the radiation image capturing apparatus 1.
Therefore, the defect pixel caused by the luminance of the electromagnetic wave irradiated from the columnar crystal of the phosphor constituting the scintillator 3 is also created without changing the quality of the radiation irradiated to the radiographic imaging device 1. Even if defective pixel correction processing is performed using a pixel map, correction may not be possible.

  On the other hand, the defective pixel map created in the present embodiment is a defective pixel map created by changing the radiation quality of the radiation applied to the radiation image capturing apparatus 1. Specifically, in the present embodiment, the radiation quality of the radiation image capturing apparatus 1 is changed, and defective pixels are determined for each radiation quality of the radiation image capturing apparatus 1 irradiated. In addition, a defective pixel map is created in which position information of pixels determined to be defective pixels in at least one of the line qualities is registered. Therefore, the defective pixel map is caused not only by the position information of the defective pixels caused by the abnormal radiation detection element 7 but also by foreign matters mixed between the sensor panel SP and the radiation incident surface R of the housing 2. Position information of defective pixels generated due to a difference in the quality of radiation irradiated to the radiographic imaging apparatus 1 such as defective pixels to be emitted and defective pixels due to the luminance of electromagnetic waves irradiated from the scintillator 3 is also registered. Yes. Therefore, if defective pixel correction processing is performed using the defective pixel map in the present embodiment, it is possible to correct defective pixels generated due to a difference in the quality of radiation irradiated to the radiation image capturing apparatus 1. .

[Defective pixel correction processing]
Next, a defective pixel correction process performed by the console 58 according to the present embodiment will be described.
Here, in the storage unit 59 of the console 58, the radiographic image capturing device 1 among the cassette ID for identifying the radiographic image capturing device 1 and the defective pixel map generated by the defective pixel map generating device 101 in advance. It is assumed that a defective pixel map is stored in association with each other.

  The defective pixel map stored in advance in the storage means 59 of the console 58 may be a defective pixel map created by the above-described defective pixel map creation method, or created by the above-described defective pixel map creation method. It may be a defective pixel map created by ORing a defective pixel map with another map. Here, as another map, for example, a map in which position information of defective pixels included in image data generated in the radiographic image capturing apparatus 1 in a state where no radiation is irradiated is registered.

  First, when receiving image data of a radiographic image generated by the radiographic image capturing apparatus 1 transmitted from the radiographic image capturing apparatus 1, the control unit 58b of the console 58 stores defective pixels stored in the storage unit 59 or the like. A defective pixel map corresponding to the cassette ID of the radiation image capturing apparatus 1 is acquired from the map.

Next, the control unit 58b performs a defective pixel correction process on the image data of the received radiation image based on the acquired defective pixel map.
Specifically, for example, the control unit 58b identifies a defective pixel with reference to the acquired defective pixel map, and receives image data of normal pixels around the identified defective pixel as an image of the received radiation image. Extract from the data. Then, using the extracted image data, correction image data is calculated by performing interpolation by a method such as simple average interpolation or weighted average interpolation. Then, the image data of the specified defective pixel included in the image data of the received radiation image is replaced with the calculated corrected image data.
In this way, defective pixel correction processing is performed by the console 58 provided in the radiographic image capturing system 100.

  According to the defective pixel map creating method and the defective pixel map creating system 100 according to the present embodiment described above, the radiation quality of the radiation image capturing apparatus 1 is changed, and the radiation image capturing apparatus 1 Map creation image data for creating a pixel map is generated for each radiation quality of radiation applied to the radiation image capturing apparatus 1, and the radiation quality of the radiation irradiated to the radiation image capturing apparatus 1 is generated. A defective pixel map in which position information of defective pixels is registered is created based on a plurality of types of map creation image data corresponding to the above.

  That is, the defective pixel map created in the present embodiment is a defective pixel map created by changing the radiation quality of the radiation irradiated to the radiation image capturing apparatus 1, so that the abnormal radiation detection element 7 In addition to the positional information of the defective pixel due to the foreign matter, foreign matter mixed in the housing 2 (specifically, foreign matter mixed between the sensor panel SP and the radiation incident surface R of the housing 2). Position information of defective pixels generated due to a difference in the quality of radiation irradiated to the radiographic imaging apparatus 1 such as defective pixels due to the defect and defective pixels due to luminance of electromagnetic waves irradiated from the scintillator 3 is also registered. ing. Accordingly, if defective pixel correction processing is performed using the defective pixel map, defective pixels generated due to the difference in the quality of radiation irradiated to the radiation image capturing apparatus 1 can be corrected. In contrast, it is possible to obtain a radiographic image with a more appropriate image quality than when performing defective pixel correction processing using a defective pixel map created without changing the radiation quality of the irradiated radiation.

  In addition, according to the defective pixel map creation method and the defective pixel map creation system according to the present embodiment described above, a plurality of types of map creation images corresponding to the radiation quality of the radiation irradiated to the radiation image capturing apparatus 1. For each data, a map by line quality in which position information of defective pixels included in the image data for map creation is registered is created, and a defective pixel map is created by performing a logical OR synthesis on the created map by line quality. It is configured as follows.

  That is, the defect pixel map created in the present embodiment changes the radiation quality of the radiation applied to the radiation image capturing apparatus 1, and is defective for each radiation quality of the radiation irradiated to the radiation image capturing apparatus 1. This is a defective pixel map in which pixel information is determined, and position information of pixels determined to be defective pixels in at least one of the line qualities is registered. Therefore, if defective pixel correction processing is performed using the defective pixel map, it is possible to accurately correct defective pixels generated due to differences in the quality of radiation irradiated to the radiographic imaging apparatus 1.

  Further, according to the console 58 according to the present embodiment described above, the defective pixel map created in the present embodiment is stored, and is generated by the radiation image capturing apparatus 1 based on the stored defective pixel map. The defective pixel correction process is performed on the image data of the radiographic image.

  That is, the console 58 performs the defective pixel correction process using the defective pixel map created by changing the radiation quality of the radiation irradiated to the radiographic image capturing apparatus 1. It is also possible to correct defective pixels generated due to the difference in radiation quality of irradiated radiation. Therefore, it is possible to obtain a radiographic image having a more appropriate image quality than when performing defective pixel correction processing using a defective pixel map created without changing the radiation quality of the radiation irradiated to the radiographic imaging apparatus 1. Is possible.

  Needless to say, the present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist of the present invention.

For example, in the above embodiment, the console 58 is configured to perform the defective pixel correction process. However, the present invention is not limited to this, and the radiographic imaging device 1 can be configured to perform the defective pixel correction process. It is.
In this case, the storage unit 40 of the radiographic imaging device 1 stores the defective pixel map created by the defective pixel map creation device 101 included in the defective pixel map creation system 100 as a storage unit that stores the defective pixel map. The control unit 22 functions as a defective pixel correction process that performs a defective pixel correction process on the image data output from the readout circuit 17 based on the defective pixel map stored in the storage unit 40.

  Further, for example, in the above embodiment, when creating a defective pixel map, the radiation voltage applied to the radiographic imaging apparatus 1 is changed by changing the tube voltage of the radiation generating apparatus 52. Although it comprised, it is not limited to this, For example, a predetermined filter is arrange | positioned between the radiation generator 52 and the radiation entrance plane R of the radiographic imaging apparatus 1, and a radiographic imaging apparatus by the said filter It is also possible to change the radiation quality of the radiation applied to 1.

  Further, for example, in the above embodiment, when the defective pixel map is created, the two voltage values of the first inspection voltage and the second inspection voltage are set as the tube voltage of the radiation generator 52. The number of voltage values to be set is arbitrary as long as a plurality of voltage values are set as the tube voltage of the radiation generating device 52 when creating a defective pixel map.

In addition, the tube voltage of the radiation generating device 52 set when the defective pixel map is created may be changed for each radiation image capturing device 1.
Specifically, for example, a voltage value smaller than the first inspection voltage is set as the second inspection voltage. Then, the line quality map corresponding to the first inspection voltage and the line quality map corresponding to the second inspection voltage are compared and registered in the line quality map corresponding to the second inspection voltage. In the case of the radiographic image capturing apparatus 1 having a larger number of pieces of position information of defective pixels, it is determined that if the tube voltage of the radiation generating apparatus 52 is further reduced, the number of defective pixels is likely to increase. A voltage smaller than the second inspection voltage is set as the tube voltage, a line quality map corresponding to a voltage smaller than the second inspection voltage is created, and the voltage is smaller than the second inspection voltage. A defective pixel map is created by logically synthesizing the corresponding line quality map, the line quality map corresponding to the first inspection voltage, and the line quality map corresponding to the second inspection voltage. On the other hand, in the case of the radiographic image capturing apparatus 1 having a larger number of pieces of position information of defective pixels registered in the map according to the line quality corresponding to the first inspection voltage, the tube voltage of the radiation generating apparatus 52 is further increased. Therefore, it is determined that the number of defective pixels is likely to increase, and a voltage larger than the first inspection voltage is set as the tube voltage of the radiation generator 52 to correspond to a voltage larger than the first inspection voltage. A map by line quality is created, a map by line quality corresponding to a voltage higher than the first inspection voltage, a map by line quality corresponding to the first inspection voltage, and a line corresponding to the second inspection voltage It is also possible to create a defective pixel map by performing a logical sum synthesis with the quality map.

  Further, for example, in the above-described embodiment, each time the radiographic image capturing apparatus 1 creates map creation image data, the radiation quality imaging apparatus 1 creates the map according to the line quality based on the created map creation image data. The present invention is not limited to this. For example, after the radiographic image capturing apparatus 1 generates a plurality of types of map creation image data corresponding to the quality of radiation irradiated to the radiographic image capturing apparatus 1, It is also possible to configure so that each line quality-specific map is created based on the map creation image data.

  Also, for example, in the above-described embodiment, a plurality of types of maps according to the radiation quality corresponding to the radiation quality of the radiation irradiated to the radiation image capturing apparatus 1 are created, and the created maps according to the radiation quality are logically combined. However, the present invention is not limited to this, and for example, it is possible to create a defective pixel map without creating a line quality-specific map. Specifically, for example, for each of a plurality of types of map creation image data corresponding to the radiation quality of the radiation irradiated to the radiation image capturing apparatus 1, a defective pixel is determined from the map creation image data, It is also possible to create a defective pixel map by sequentially registering the determined position information of defective pixels in the defective pixel map.

  Also, for example, in the above-described embodiment, a plurality of types of maps according to the radiation quality corresponding to the radiation quality of the radiation irradiated to the radiation image capturing apparatus 1 are created, and the created maps according to the radiation quality are logically combined. However, the present invention is not limited to this, and is based on a plurality of types of map creation image data corresponding to the quality of radiation irradiated to the radiation image capturing apparatus 1. If the defective pixel map in which the position information of the defective pixel is registered can be created, for example, the line having the largest number of registered position information of the defective pixel among the plurality of types of created line quality-specific maps. It is also possible to configure so that the quality map is selected as the defective pixel map.

Further, for example, it is possible to configure so that the defective pixel map can be created not only by the defective pixel map creation system 100 but also by the radiation image capturing system 50.
Specifically, the console 58 is provided with a defective pixel map creation function equivalent to the defective pixel map creation device 101, and the console 58 is used when calibrating the radiation image capturing device 1 operated in the radiation image capturing system 50. The controller 58b can create a defective pixel map and update the defective pixel map stored in the storage unit 59 of the console 58 with the created defective pixel map.
In this case, the radiographic imaging system 50 functions as a defective pixel map creation system, the console 58 functions as a defective pixel map creation device, and the control unit 58b of the console 58 functions as a defective pixel map creation means.

In addition, for example, a foreign substance mixed in the housing 2 is detected based on a plurality of types of maps according to the radiation quality corresponding to the radiation quality of the radiation applied to the radiation imaging apparatus 1. It is also possible.
Specifically, for example, the position and the number of defective pixels registered in the map for each line quality corresponding to the first inspection voltage, and the defect registered in the map for each line quality corresponding to the second inspection voltage. When the positions and number of pixels are different, there is a high possibility that foreign matter is mixed between the sensor panel SP and the radiation incident surface R of the housing 2. Therefore, in such a case, for example, the control unit 101b of the defective pixel map creating apparatus 101 determines that a foreign substance is mixed in the housing 2, and this is indicated by the display unit 101a of the defective pixel map creating apparatus 101. It is also possible to configure so as to notify by displaying or the like. As a result, the foreign matter mixed in the housing 2 can be removed by wiping the surface on the radiation incident surface R side of the sensor panel SP, so that the foreign matter mixed in the housing 2 is removed. The radiographic image capturing apparatus 1 can be shipped. In addition, when the foreign substance mixed in the housing | casing 2 of the radiographic imaging apparatus 1 is removed, radiation is irradiated again to the said radiographic imaging apparatus 1, and irradiation to the said radiographic imaging apparatus 1 is performed. It is preferable to create a plurality of types of maps according to the quality of radiation according to the quality of the radiation to be generated, and to create a defective pixel map based on the created maps according to the quality of radiation.

DESCRIPTION OF SYMBOLS 1 Radiation imaging device 17 Reading circuit 22 Control means (Generation means, defective pixel correction means)
40 storage means 52 radiation generator 58 console 58b control unit (defective pixel correction means)
59 Storage means 100 Defective pixel map creation system 101 Defective pixel map creation apparatus 101b Control unit (defective pixel map creation means)
SP sensor panel

Claims (7)

In a defective pixel map creating method for creating a defective pixel map used when correcting defective pixels included in image data of a radiographic image generated by a radiographic imaging device,
A change step of changing the radiation quality of the radiation applied to the radiographic imaging device;
The radiation image capturing apparatus generates map creation image data for creating the defective pixel map for each radiation quality of radiation irradiated to the radiation image capturing apparatus,
A defective pixel map that creates the defective pixel map in which position information of the defective pixels is registered based on a plurality of types of map creation image data corresponding to radiation quality irradiated to the radiographic imaging device Creation steps,
A defective pixel map creating method characterized by comprising: The defective pixel map creating step includes
For each of the plurality of types of map creation image data, a line quality specific map creation step of creating a map by line quality in which position information of defective pixels included in the map creation image data is registered;
A synthesizing step for creating the defective pixel map by performing a logical OR synthesis on each line quality map created in the line quality map creation step;
The defective pixel map creating method according to claim 1, wherein: A radiographic imaging apparatus that performs radiographic imaging, a radiation generation apparatus that irradiates radiation to the radiographic imaging apparatus, and correction of defective pixels included in image data of the radiographic image generated by the radiographic imaging apparatus In a defective pixel map creation system comprising a defective pixel map creation device that creates a defective pixel map to be used at the time,
The radiation generator is capable of changing the radiation quality of the radiation applied to the radiographic imaging device,
The radiographic image capturing device includes a generating unit that generates map creation image data for creating the defective pixel map for each radiation quality of radiation irradiated to the radiographic image capturing device,
The defect pixel map creation device includes the defect in which position information of the defective pixel is registered based on a plurality of types of map creation image data corresponding to radiation quality irradiated to the radiographic imaging device. A defective pixel map creating system comprising defective pixel map creating means for creating a pixel map. The defective pixel map creating means includes:
For each of the plurality of types of map creation image data, create a map according to line quality in which position information of defective pixels included in the map creation image data is registered,
4. The defective pixel map creating system according to claim 3, wherein the defective pixel map is created by performing a logical sum synthesis on each of the created maps according to line quality.   5. The defective pixel map creation system according to claim 3, wherein the radiation quality of the radiation is changed by changing a tube voltage of the radiation generator. In a console that performs predetermined image processing on image data of a radiographic image generated by the radiographic imaging device,
Storage means for storing a defective pixel map created by the defective pixel map creating device provided in the defective pixel map creating system according to any one of claims 3 to 5;
Based on the defective pixel map stored in the storage means, defective pixel correction means for performing defective pixel correction processing on the image data of the radiographic image generated by the radiographic imaging device;
A console characterized by comprising. A sensor panel comprising a plurality of radiation detection elements arranged two-dimensionally;
A readout circuit that reads out charges from the radiation detection elements, converts the charges into electrical signals for each of the radiation detection elements, and outputs them as image data;
Storage means for storing a defective pixel map created by the defective pixel map creating device provided in the defective pixel map creating system according to any one of claims 3 to 5;
Defective pixel correction means for performing defective pixel correction processing on the image data output by the readout circuit based on the defective pixel map stored in the storage means;
A radiographic imaging apparatus comprising:

Images