JP2013138280A - Radiation image photographing device and radiation image photographing system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiation image photographing device which can precisely detect irradiation start of a radiation ray with the device itself by using an existing function section in the device.SOLUTION: Control means 22 of a radiation image photographing device 1 allows repeat of: reading processing for applying ON-state voltage from a gate driver 15b to a single or a plurality of scan lines 5d which are previously designated among all scan lines 5 connected to a gate driver 5b of scan driving means 15 before a radiation image is photographed to read irradiation start detection data d; and reset processing of respective radiation detection elements 7 for sequentially applying the ON-state voltage to a single or a plurality of scan lines 5 except for the plurality of scan lines 5d which are previously designated from the gate driver 15b. The control means detects that irradiation of a radiation ray is started on the basis of the irradiation start detection data d which is read.

Description

  The present invention relates to a radiographic imaging apparatus and a radiographic imaging system, and more particularly to a radiographic imaging apparatus that performs radiographic imaging by detecting the start of radiation irradiation by the apparatus itself and a radiographic imaging system using the same.

  A so-called direct-type radiographic imaging device that generates electric charges by a detection element in accordance with the dose of irradiated radiation such as X-rays and converts it into an electrical signal, or other radiation such as visible light with a scintillator A so-called indirect radiographic imaging device that converts an electromagnetic wave having a wavelength and then generates a charge in a photoelectric conversion element such as a photodiode according to the energy of the converted electromagnetic wave and converts it to an electrical signal (ie, image data). 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 is known as an FPD (Flat Panel Detector), and conventionally formed integrally with a support base (or a bucky apparatus) (see, for example, Patent Document 1). A portable radiographic image capturing apparatus in which an element or the like is stored in a housing and made portable is developed and put into practical use (see, for example, Patent Documents 2 and 3).

  In such a radiographic imaging apparatus, for example, as shown in FIG. 7 and the like to be described later, normally, a plurality of radiation detection elements 7 are arranged in a two-dimensional form (matrix) on the detection unit P, and each radiation detection element 7 is connected to switch means formed of thin film transistors (hereinafter referred to as TFTs) 8. Then, an ON voltage or an OFF voltage is applied to each scanning line 5 from the gate driver 15b of the scanning driving unit 15, and each TFT 8 is turned on / off, and charge accumulation in each radiation detection element 7 is performed. Release of charges from each radiation detection element 7 to each signal line 6 is performed.

  Conventional radiographic imaging is configured to perform radiographic imaging while exchanging signals and information between the radiographic imaging apparatus and the radiation generation apparatus, that is, in cooperation with each other. However, when the manufacturers of the radiographic imaging apparatus and the radiation generation apparatus are different, there are cases where it is not possible to accurately exchange signals and the like between the two as described above.

  In such a case, the radiation imaging apparatus itself detects that the radiation has been irradiated, and the charges generated in each radiation detecting element 7 due to the radiation irradiation are accurately determined in each radiation detecting element 7. In addition, it is necessary to configure such that the charges are read out as image data D after irradiation with radiation.

  As a method for detecting radiation irradiation by the radiographic imaging apparatus itself, for example, as described in Patent Document 3, an X-ray sensor is provided in the radiographic imaging apparatus, and whether or not radiation has been irradiated according to the output value. If the radiation image capturing apparatus is irradiated with radiation as described in, for example, Patent Document 4, wiring in the apparatus (for example, a bias line 9 and a connection line 10 described later) Utilizing the fact that the current flowing in the inside increases, a current detection means is provided in the radiographic imaging apparatus, and the radiation imaging apparatus itself detects radiation irradiation by monitoring the output from the current detection means. It is possible to configure.

JP-A-9-73144 JP 2006-058124 A JP-A-6-342099 JP 2009-219538 A

  However, when the X-ray sensor and the current detection unit are newly provided in the radiographic imaging apparatus as described above, for example, a space for arranging the X-ray sensor in the radiographic imaging apparatus is newly provided. There arises a new problem that is not always easy to solve, such as a need to be generated or noise generated by the current detection means, such as deterioration of the S / N ratio of the read image data D.

  Therefore, the radiographic imaging apparatus can accurately start the radiation irradiation by the apparatus itself, for example, using an existing function unit provided in the radiographic imaging apparatus, without using such an X-ray sensor or current detection means. It is desired to configure so that it can be detected.

  The present invention has been made in view of the above-described problems, and provides a radiographic imaging apparatus capable of accurately detecting the start of radiation irradiation by the apparatus itself using an existing functional unit in the apparatus. For the purpose.

  Further, in the new radiation irradiation start detection method developed by the present inventors, image data D that cannot be used to generate a radiation image is included in the image data D read from each radiation detection element 7. Will occur. That is, line defects are inevitably generated. Therefore, it is required to accurately correct the image and generate a radiographic image accurately.

  Accordingly, the present invention provides a radiographic image capable of accurately correcting a line defect in the image data D generated when the above detection method is employed in a radiographic imaging system using the above radiographic imaging apparatus. Another object is to provide a photographing system.

In order to solve the above-described problem, the radiographic imaging device of the present invention includes:
A plurality of scanning lines and a plurality of signal lines arranged so as to intersect with each other, and a plurality of radiation detection elements arranged in a two-dimensional manner in each small region partitioned by the plurality of scanning lines and the plurality of signal lines A detection unit comprising:
A scanning driving means comprising a gate driver for switching on and applying an on voltage and an off voltage to each scanning line;
Switch means connected to each of the scanning lines and causing the signal lines to discharge charges accumulated in the radiation detection element when an on-voltage is applied;
A readout circuit that converts the electric charge emitted from the radiation detection element into image data and reads the image data;
Control means for controlling at least the scanning drive means and the readout circuit to perform readout processing of the image data from the radiation detection element;
With
The control means includes
Prior to radiographic imaging, an on-voltage is applied from the gate driver to one or a plurality of the scanning lines designated in advance among all the scanning lines connected to the gate driver of the scanning driving means. Read processing for reading irradiation start detection data, and reset processing of each radiation detection element performed by sequentially applying an on-voltage from the gate driver to one or a plurality of the scanning lines other than the plurality of scanning lines designated in advance And repeatedly
It is detected that radiation irradiation has started based on the read irradiation start detection data.

Moreover, the radiographic imaging system of the present invention is
The radiographic imaging apparatus including the communication unit;
An image processing device that generates a radiographic image based on the image data transmitted from the radiographic imaging device via the communication unit;
With
The image processing apparatus scans the image data read from the radiation detection elements connected to the plurality of scanning lines designated in advance in the radiation imaging apparatus on the detection unit. Image correction is performed using the image data read from each of the radiation detection elements connected to the scanning line adjacent to the line.

  According to the radiographic imaging apparatus and radiographic imaging system of the system as in the present invention, each functional unit such as a scanning drive unit and a readout circuit already provided in the radiographic imaging apparatus is used to read before radiographic imaging. Based on the emitted irradiation start detection data, the radiation imaging apparatus itself can accurately detect the radiation irradiation start.

  Therefore, as described above, it is not necessary to newly provide an X-ray sensor or current detection means in the radiographic imaging apparatus. For example, a space for arranging the X-ray sensor in the radiographic imaging apparatus is newly provided. It is possible to accurately prevent problems such as deterioration of the S / N ratio of the image data D due to noise generated by the current detection means.

  In addition, it is possible to accurately correct a line defect in the image data D generated when the above detection method is employed.

It is sectional drawing of the radiographic imaging apparatus which concerns on this embodiment. It is a top view which shows the structure of the board | substrate of a radiographic imaging apparatus. It is a block diagram showing the equivalent circuit of a radiographic imaging apparatus. It is a block diagram showing the equivalent circuit about 1 pixel which comprises a detection part. 6 is a timing chart showing charge reset switches, pulse signals, and TFT on / off timings in image data read processing. It is a figure which shows the structural example of the radiographic imaging system which concerns on this embodiment constructed | assembled in the imaging | photography room. It is a figure which shows the structural example of the radiographic imaging system which concerns on this embodiment constructed | assembled on the round-trip vehicle. It is a figure explaining the state from which the data for irradiation start detection are read from each radiation detection element connected to the detection line. It is the graph which plotted the data for irradiation start detection read out in time series. 6 is a timing chart showing the timing at which an on-voltage is applied to each scanning line when the irradiation start detection data reading process and each radiation detection element reset process are alternately performed in the present embodiment. 11 is a timing chart showing the timing of applying an on-voltage to each scanning line in a configuration example different from FIG. 12 is a timing chart showing the timing of applying an on-voltage to each scanning line before shifting to a charge accumulation state and performing image data read processing after FIG. 10 and FIG. It is a figure showing the 1st line defect which appears in one line shape in image data. It is a graph showing the time transition of the dose rate of the radiation irradiated from the radiation source, (A) represents the case where the dose rate rises immediately immediately after the start of irradiation, and (B) the dose rate increased in proportion to time. It represents the case where it becomes constant afterwards. It is a figure showing the 2nd line defect which a line defect may appear continuously in image data. It is a graph showing the example of the profile of the average value for every figure which represents the example of each true image data, and every scanning line. It is a graph showing the example of the profile of the average value for every scanning line from which it became difficult to understand the range of the true image data which has generate | occur | produced the defect by the influence of the true image data of the big value which has not generate | occur | produced the defect. (A) It is a figure showing the example of the true image data extracted by subject area recognition processing, (B) It is a graph showing the example of distribution of the extracted true image data, (C) The decided subject It is a figure showing the example of the area | region where is image | photographed. It is a graph explaining an example of the method of specifying the range of the true image data which has produced the defect | deletion. It is a graph explaining that the absolute value of the difference between the average values may be less than a threshold value in the range of true image data causing a defect. It is a graph showing the example of the straight line which approximated each average value except the average value specified as the range of the true image data which has produced the defect | deletion. (A) The example of the profile of the average value of each true image data before normalization, and (B) The graph showing the example of the profile of the average value of each true image data after normalization. It is a graph showing the straight line etc. which approximate each average value in each scanning line before and behind the detection line except the scanning line except the scanning line in which the line defect may appear among FIG.22 (B). It is a graph showing the fall rate for every scanning line 5 of the actual average value with respect to the straight line of FIG. It is a graph showing each approximate line at the time of changing the predetermined number of scanning lines including a detection line. It is a graph showing the example of the approximate line extracted from each approximate line of FIG. It is a graph showing the average value for every scanning line of the true image data before being restored and after being restored.

  Embodiments of a radiographic imaging apparatus and a radiographic imaging system according to the present invention will be described below with reference to the drawings.

  In the following description, a so-called indirect radiation image capturing apparatus that includes a scintillator or the like and converts an emitted radiation into an electromagnetic wave having another wavelength such as visible light to obtain an electrical signal will be described. 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.

  Although the case where the radiographic imaging apparatus is a so-called portable type will be described, the present invention can also be applied to a so-called dedicated machine type radiographic imaging apparatus formed integrally with a support base or the like. Is possible.

[Radiation imaging equipment]
First, the radiographic imaging device according to the present embodiment will be described. FIG. 1 is a cross-sectional view of a radiographic image capturing apparatus according to the present embodiment, and FIG. 2 is a plan view illustrating a configuration of a substrate of the radiographic image capturing apparatus.

  As shown in FIG. 1, the radiographic image capturing apparatus 1 includes a scintillator 3, a substrate 4, and the like in a housing 2 formed of a carbon plate having a radiation incident surface R that is a surface irradiated with radiation. The configured sensor panel SP is housed. Although not shown in FIG. 1, in this embodiment, the housing 2 is an antenna that is a communication means for transmitting image data D and the like to a console 58 (see FIG. 6 and FIG. 7) to be described later in a wireless manner. A device 41 (see FIG. 3 described later) is provided.

  Although not shown in FIG. 1, in the present embodiment, the radiographic image capturing apparatus 1 includes a connector on the side surface of the housing 2 or the like, and a console 58 receives signals and data in a wired manner via the connector. Etc. can be sent to. For this reason, this connector also functions as a communication means of the radiation image capturing apparatus 1.

  As shown in FIG. 1, a base 31 is disposed in the housing 2, and a lead thin plate or the like (not shown) is provided on the radiation incident surface R side (hereinafter simply referred to as the upper surface side) of the base 31. A substrate 4 is provided. A scintillator 3 that converts irradiated radiation into light such as visible light is provided on the scintillator substrate 34 on the upper surface side of the substrate 4, and the scintillator 3 is provided facing the substrate 4 side.

  Further, on the lower surface side of the base 31, a PCB substrate 33 on which electronic components 32 and the like are arranged, a battery 24, and the like are attached. In this way, the sensor panel SP is formed by the base 31, the substrate 4, and the like. In the present embodiment, the buffer material 35 is provided between the sensor panel SP and the side surface of the housing 2.

  In the present embodiment, the substrate 4 is formed of a glass substrate, and as shown in FIG. 2, a plurality of scanning lines 5 and a plurality of signals are provided on the upper surface 4a of the substrate 4 (that is, the surface facing the scintillator 3). The lines 6 are arranged so as to intersect 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 small region r provided with a plurality of radiation detection elements 7 arranged in a two-dimensional form (matrix) in each small region r partitioned by the scanning lines 5 and the signal lines 6, that is, FIG. The area indicated by the alternate long and short dash line in FIG. In the present embodiment, a photodiode is used as the radiation detection element 7, but a phototransistor or the like can also be used, for example.

  Here, the circuit configuration of the radiation image capturing apparatus 1 will be described. FIG. 3 is a block diagram illustrating an equivalent circuit of the radiographic image capturing apparatus 1 according to the present embodiment, and FIG. 4 is a block diagram illustrating an equivalent circuit for one pixel constituting the detection unit P.

  The first electrode 7a of each radiation detection element 7 is connected to a source electrode 8s (see “S” in FIG. 3 and FIG. 4) of a TFT 8 serving as a switch means. Further, the drain electrode 8d and the gate electrode 8g (see “D” and “G” in FIGS. 3 and 4) of the TFT 8 are connected to the signal line 6 and the scanning line 5, respectively.

  The TFT 8 is turned on when a turn-on voltage is applied to the gate electrode 8g via the scanning line 5 from the scanning driving means 15 described later, and is accumulated in the radiation detection element 7 via the source electrode 8s and the drain electrode 8d. The charged electric charge is discharged to the signal line 6. Further, when a turn-off voltage is applied to the gate electrode 8 g via the scanning line 5, the gate electrode 8 g is turned off, the discharge of charge from the radiation detection element 7 to the signal line 6 is stopped, and charge is accumulated in the radiation detection element 7. It is supposed to let you.

  In the present embodiment, as shown in FIGS. 2 and 3, the bias line is applied to the second electrode 7 b of each radiation detection element 7 at a rate of one for each radiation detection element 7 in a row on the substrate 4. 9 is connected, and each bias line 9 is bound to the connection 10 at a position outside the detection portion P of the substrate 4. The connection 10 is connected to a bias power supply 14 (see FIGS. 3 and 4) via an input / output terminal 11 (also referred to as a pad, see FIG. 2). The connection 10 and each bias line 9 are connected from the bias power supply 14 to the connection. Thus, a reverse bias voltage is applied to the second electrode 7b of each radiation detection element 7.

  On the other hand, each scanning line 5 is connected to the gate driver 15b of the scanning driving means 15 via the input / output terminal 11, respectively. In the scanning drive means 15, an ON voltage and an OFF voltage are supplied from the power supply circuit 15a to the gate driver 15b via the wiring 15c, and applied to the lines L1 to Lx of the scanning line 5 by the gate driver 15b. The voltage is switched between an on voltage and an off voltage.

  Each signal line 6 is connected to each readout circuit 17 built in the readout IC 16 via each input / output terminal 11. In the present embodiment, the readout circuit 17 is mainly composed of an amplification circuit 18 and a correlated double sampling circuit 19. An analog multiplexer 21 and an A / D converter 20 are further provided in the read IC 16. 3 and 4, the correlated double sampling circuit 19 is represented as CDS.

In the present embodiment, the amplifier circuit 18 is a charge amplifier circuit including an operational amplifier 18a, a capacitor 18b and a charge reset switch 18c connected in parallel to the operational amplifier 18a, and a power supply unit 18d that supplies power to the operational amplifier 18a and the like. It consists of The signal line 6 is connected to the inverting input terminal on the input side of the operational amplifier 18 a of the amplifier circuit 18, and the reference potential V ₀ is applied to the non-inverting input terminal on the input side of the amplifier circuit 18. ing.

  The charge reset switch 18 c of the amplifier circuit 18 is connected to the control means 22, and is turned on / off by the control means 22. Further, a switch 18e that opens and closes in conjunction with the charge reset switch 18c is provided between the operational amplifier 18a and the correlated double sampling circuit 19, and the switch 18e is turned on / off by the charge reset switch 18c. It is designed to be turned off / on in conjunction with

  In the process of reading the image data D from each radiation detection element 7, as shown in FIG. 5, the TFT 8 of each radiation detection element 7 is in a state where the charge reset switch 18c of the amplifier circuit 18 is turned off. When the ON voltage is applied to the signal line 6, electric charges are discharged from the radiation detection elements 7 to the signal lines 6, and flow into the capacitors 18 b of the amplification circuits 18 of the readout circuits 17 to be accumulated. In the amplifier circuit 18, a voltage value corresponding to the amount of charge accumulated in the capacitor 18b is output from the output side of the operational amplifier 18a.

  The correlated double sampling circuit 19 outputs an increase in the output value from the amplifier circuit 18 before and after the charge flows from each radiation detection element 7 as analog value image data D to the downstream side. The output image data D is sequentially transmitted to the A / D converter 20 via the analog multiplexer 21, and is sequentially converted into digital image data D by the A / D converter 20 and stored in the storage means 23. Output and save sequentially. In this way, the reading process of the image data D is performed.

  The control means 22 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an input / output interface, etc., not shown, connected to a bus, an FPGA (Field Programmable Gate Array), or the like. It is configured. It may be configured by a dedicated control circuit.

  Then, the control unit 22 controls the operation of each functional unit of the radiographic imaging apparatus 1 such as controlling the scanning driving unit 15 and the readout circuit 17 to perform the readout process of the image data D as described above. It has become. As shown in FIGS. 3 and 4, the control means 22 is connected to a storage means 23 composed of SRAM (Static RAM), SDRAM (Synchronous DRAM) or the like.

  In the present embodiment, the control unit 22 is connected to the antenna device 41 described above, and is further necessary for each functional unit such as the scanning drive unit 15, the readout circuit 17, the storage unit 23, and the bias power source 14. A battery 24 for supplying power is connected.

  Note that the configuration, control, and the like for the radiation irradiation start detection process in the radiographic imaging apparatus 1 will be described after the radiographic imaging system 50 according to the present embodiment has been described.

[Radiation imaging system]
Next, the radiographic image capturing system 50 according to the present embodiment will be described. FIG. 6 is a diagram illustrating a configuration example of the radiation image capturing system 50 according to the present embodiment. In FIG. 6, the case where the radiographic imaging system 50 is constructed in the imaging room R1 is shown.

  A bucky device 51 is installed in the radiographing room R1, and the bucky device 51 can be used by loading the radiographic imaging device 1 in a cassette holding portion (also referred to as a cassette holder) 51a. It has become. FIG. 6 shows a case where a bucky device 51A for standing position shooting and a bucky device 51B for standing position shooting are installed as the bucky device 51. For example, only one of the bucky devices 51 is provided. It may be done.

  As shown in FIG. 6, the imaging room R1 is provided with at least one radiation source 52A for irradiating the radiation image capturing apparatus 1 mounted on the Bucky apparatus 51 via a subject. In the present embodiment, by moving the position of the radiation source 52A or changing the irradiation direction of the radiation, radiation is applied to both the standing-up imaging device 51A and the standing-up imaging device 51B. Can be done.

  The imaging room R1 is provided with a repeater (also referred to as a base station or the like) 54 for relaying communication between the devices in the imaging room R1 and the devices outside the imaging room R1. In the present embodiment, the repeater 54 is provided with a wireless antenna (also referred to as an access point) 53 so that the radiation image capturing apparatus 1 can transmit and receive image data D and signals in a wireless manner. It has been.

  The repeater 54 is connected to the radiation generator 55 and the console 58, and LAN (Local Area Network) communication is transmitted to the repeater 54 from the radiation imaging apparatus 1, the console 58, and the like to the radiation generator 55. A converter (not shown) that converts a signal for use into a signal for use in the radiation generator 55 and the reverse conversion is incorporated.

  In the present embodiment, the front room (also referred to as an operation room) R2 is provided with an operation console 57 of the radiation generating device 55. The operation panel 57 is operated by an operator such as a radiation engineer. An exposure switch 56 is provided for instructing the generator 55 to start radiation irradiation. The radiation generating device 55 is configured to emit radiation from the radiation source 52 when the exposure switch 56 is operated by the operator. Further, various controls such as adjusting the radiation source 52 so as to emit an appropriate dose of radiation are performed.

  As shown in FIG. 6, in the present embodiment, a console 58 constituted by a computer or the like is provided in the front chamber R2. The console 58 can be configured to be provided outside the imaging room R1 and the front room R2, in a separate room, and the like, and is installed in an appropriate place.

  Further, the console 58 is provided with a display unit 58a configured to include a CRT (Cathode Ray Tube), an LCD (Liquid Crystal Display), and the like, and also includes input means such as a mouse and a keyboard (not shown). Yes. In addition, the console 58 is connected to or has a built-in storage means 59 composed of an HDD (Hard Disk Drive) or the like.

  On the other hand, as shown in FIG. 7, the radiographic imaging device 1 is not loaded in the bucky device 51, and can be used in a so-called state. For example, when the patient H cannot get up from the bed B of the hospital room R3 and cannot go to the imaging room R1, the radiographic imaging device 1 is brought into the hospital room R3 as shown in FIG. It can be used by being inserted into the patient's body or applied to the patient's body.

  When the radiographic image capturing apparatus 1 is used in a hospital room R3 or the like, a so-called portable radiation generating apparatus 55 is provided, for example, as a round-trip car, as shown in FIG. 7, instead of the radiation generating apparatus 55 installed in the above-described imaging room R1. It is brought into hospital room R3 by being mounted on 71 or the like. In this case, the radiation 52P of the portable radiation generator 55 is configured to be able to emit radiation in an arbitrary direction, and is inserted between the bed B and the patient's body or applied to the patient's body. The radiation image capturing apparatus 1 can be irradiated with radiation from an appropriate distance and direction.

  Further, in this case, a repeater 54 provided with a wireless antenna 53 is built in the radiation generation device 55, and, similarly to the above, the repeater 54 communicates between the radiation generation device 55 and the console 58, The communication between the radiation image capturing apparatus 1 and the console 58, the transmission of image data D, and the like are relayed.

  As shown in FIG. 6, the radiographic imaging device 1 is composed of the body of a patient (not shown) lying on the bucky device 51 </ b> B for supine photography in the photographing room R <b> 1 and the bucky device 51 </ b> B for supine photography. It can also be used by being inserted between them or being applied to the patient's body on the bucky device 51B for lying position photography. In this case, the portable radiation 52P or the radiation source 52A installed in the photographing room R1 is used. Either of these can be used.

  In the present embodiment, the console 58 also functions as an image processing device. When image data D or the like is transmitted from the radiographic image capturing device 1, offset correction, gain correction, and defective pixels are based on the data. A radiographic image is generated by performing precise image processing such as correction and gradation processing according to the imaging region.

[Configuration and control for detection processing in radiographic equipment]
Next, a configuration, control, and the like for the radiation irradiation start detection process in the radiographic imaging apparatus 1 according to the present embodiment will be described. The operation of the radiographic image capturing apparatus 1 according to this embodiment will also be described.

  In the present embodiment, the control unit 22 includes a single or a plurality of pre-designated scanning lines 5 among all the scanning lines 5 connected to the gate driver 15b (see FIG. 3) of the scanning driving unit 15 before radiographic image capturing. Read processing for reading the irradiation start detection data d by applying an on-voltage from the gate driver 15b to the scanning line 5 (hereinafter referred to as the detection line 5d) is performed.

  In addition, the readout process and the reset process of each radiation detection element 7 performed by sequentially applying the on-voltage to one or a plurality of scanning lines 5 other than the detection line 5d from the gate driver 15b are repeatedly performed, and the readout irradiation is performed. Based on the start detection data d, the start of radiation irradiation is detected. This will be specifically described below.

  Hereinafter, a case where a plurality of scanning lines 5 among all the scanning lines 5 on the detection unit P of the radiation imaging apparatus 1 are designated in advance as the detection lines 5d will be described. For example, as the detection lines 5d It is also possible to configure so that only one scanning line 5 such as the central portion of the detection portion P is designated in advance.

  In the following, a case where the reset process of each radiation detection element 7 and the read process of the irradiation start detection data d are alternately performed will be described. For example, the read process is performed after the reset process is performed several times. It is also possible to configure to repeat in the order in which they are performed (that is, repeat the order of reset processing, reset processing, and readout processing, for example). It is possible to make it perform at the timing.

  In the present embodiment, as shown in FIG. 8, the detection line 5 d is provided for every predetermined number of scanning lines 5 such as 100 out of all the scanning lines 5 on the detection unit P of the radiographic imaging apparatus 1. Are designated in advance. As shown in FIGS. 2 and 3, one scanning line 5 is provided for each radiation detection element 7, and the size of the detection part P of one radiation detection element 7 on the plane is as follows. Thus, as described above, the interval in the real space of the detection line 5d is determined by how many scanning lines 5 are designated for the detection line 5d.

  In the present embodiment, the control means 22 simultaneously applies an on-voltage from the gate driver 15b to the detection lines 5d before radiographic imaging. Then, as shown in FIG. 8, charges are discharged from the radiation detection elements 7 (not shown in FIG. 8) connected to the detection lines 5 d to the signal lines 6, and the capacitors of the amplification circuit 18 of the readout circuit 17. In order to flow into 18b, data corresponding to the total value of the charges discharged from each radiation detection element 7 is read out as the irradiation start detection data d.

  In the present embodiment, a threshold value dth is provided for the irradiation start detection data d, for example, as shown in FIG. 9, and the control means 22 determines whether or not the read irradiation start detection data d exceeds the threshold value dth. To come to judge.

  The read-out irradiation start detection data d corresponds to the total value of so-called dark charges (also referred to as dark current) generated in each radiation detection element 7 before the radiation image capturing apparatus 1 is irradiated with radiation. A relatively small value. However, when radiation irradiation is started on the radiation image capturing apparatus 1, charges are generated in each radiation detection element 7 due to radiation irradiation, which is read out as irradiation start detection data d. The value of the irradiation start detection data d becomes significantly larger than the previous value and exceeds the threshold value dth (see time t1 in FIG. 9).

  As described above, the control means 22 is configured to monitor the value of the irradiation start detection data d read for each reading process, and detect the radiation irradiation start when the value exceeds the threshold value dth. The radiation image capturing apparatus 1 itself can accurately detect that the radiation image capturing apparatus 1 has started irradiation with radiation.

  On the other hand, in order not to interfere with the process of reading and detecting charges from the radiation detecting elements 7 connected to the detection line 5d, the off voltage is always applied to the scanning lines 5 other than the detection line 5d. Then, each TFT 8 connected to the scanning line 5 other than the detection line 5d is always turned off.

  However, if such a state continues, dark charges continue to be accumulated in the radiation detection elements 7 connected to the scanning lines 5 other than the detection line 5d via the TFTs 8. When the amount of dark charge accumulated in each radiation detection element 7 increases, the capacity for storing useful charges generated in each radiation detection element 7 due to irradiation of radiation decreases, and each radiation detection element 7. The dynamic range becomes narrow (or the dynamic range disappears in extreme cases).

  Therefore, in this embodiment, as shown in FIG. 10, the gate driver 15b turns on the scanning lines 5 other than the detection lines 5d alternately with the reading process of the irradiation start detection data d from the detection lines 5d. A voltage is sequentially applied to reset each radiation detection element 7.

  At that time, as shown in FIG. 10, it is also possible to apply the on-voltage one by one to the scanning lines 5 other than the detection line 5d and shift the scanning lines 5 to which the on-voltage is applied. For example, as shown in FIG. 11, a plurality of ON voltages are simultaneously applied to the scanning lines 5 other than the detection lines 5d, and the scanning lines 5 to which the ON voltages are applied are shifted. It is also possible to configure as described above.

  When configured as shown in FIG. 11, the reset process is performed in each radiation detection element 7 connected to the scanning line 5 other than the detection line 5 d, so that the dark charge accumulated in each radiation detection element 7 is shortened. There is a merit that it becomes possible to reduce the amount of. On the other hand, as will be described later, a line defect is generated by performing the reset process of each radiation detection element 7 as described above, and a line defect that occurs when configured as shown in FIG. 11 (that is, a second defect described later). The number of line defects) increases, but the configuration as shown in FIG. 10 has an advantage that the number of line defects generated can be reduced.

  10 and 11 show the case where one detection line 5d is set for each of the five scanning lines 5 (lines L1 to Lx; see FIG. 3). This is for easy understanding. Actually, one detection line 5 d is set for every several tens to several hundreds of scanning lines 5.

  Further, in FIG. 10 and FIG. 11, “d” at the bottom of the figure is a process for reading out irradiation start detection data d from the detection line 5 d during that period, and “R” is the detection of each radiation during that period. It represents that the reset process of the element 7 is performed. Furthermore, since the charge is released from the radiation detection elements 7 to the signal lines 6 when the irradiation start detection data d is read, it is not necessary to reset the radiation detection elements 7 in the detection line 5d. (Refer to FIG. 10 and FIG. 11) It is also possible to perform a reset process for each radiation detection element 7 in the detection line 5d.

  If comprised as mentioned above, it will become possible to detect correctly that the irradiation of the radiation started in the radiographic imaging device 1 itself by performing the reading process of the irradiation start detection data d in the detection line 5d. At the same time, for each radiation detection element 7 connected to the scanning line 5 other than the detection line 5d, the reset process of each radiation detection element 7 is appropriately performed. It is possible to accurately remove the residual charges from the radiation detecting elements 7.

  8, 10, and 11, the detection line 5 d (that is, a plurality of scanning lines 5 specified in advance) is the first line L <b> 1 or the last line Lx (see FIG. 3) of the scanning line 5. As described above, it is desirable to specify in advance so as not to include the scanning line 5 at the end portion on the detection unit P. This will be described in the description of image correction described later.

  In the above description, it has been described on the assumption that the reading process of the irradiation start detection data d is performed for each readout circuit 17, but in reality, the number of readout circuits 17 (that is, the number of signal lines) is If it is configured to perform the above-described processing for several thousand to several tens of thousands, the detection process of the start of radiation irradiation becomes a very heavy process.

  Therefore, for example, by using the fact that a large number of readout circuits 17 such as 128 or 256 are formed in the readout IC 16 (see FIGS. 3 and 4), the irradiation read out by each readout circuit 17 is used. Calculate the average value, total value, intermediate value, etc., for each read IC 16 such as start detection data d, and detect whether the irradiation value has started by determining whether the average value, etc., for each read IC 16 has exceeded a threshold. It can be configured to do so.

  In addition, for example, the maximum value and the minimum value are extracted from the average value for each reading IC 16 such as the irradiation start detection data d, and the difference value is calculated, and the difference value exceeds the set threshold value. It is also possible to determine whether or not to detect the start of radiation irradiation.

  If comprised as mentioned above, the number of the data used for the detection process of radiation irradiation start, and the number of numerical values will decrease, and it will become possible to make the radiation irradiation start detection process light processing. Therefore, the time required for the detection process is shortened, and it becomes possible to detect the start of radiation irradiation on the radiation image capturing apparatus 1 in real time.

  It goes without saying that further improvements can be added to the detection process of the start of radiation irradiation.

  For example, when the radiation image capturing apparatus 1 is irradiated with radiation having a small dose rate (that is, a dose per unit time), the irradiation start detection data d and the like read when the radiation image capturing apparatus 1 starts irradiation with radiation. However, the threshold dth (see FIG. 9) or the like may not be exceeded even if it increases, and eventually the start of radiation irradiation may not be detected.

  Therefore, in such a case, the irradiation start detection data d read out as described above is not directly used for the radiation irradiation start detection process, but is used for each irradiation start detection data d reading process. It is possible to configure such that the integration is performed and the integrated value is used for the detection process of the start of radiation irradiation.

  However, the irradiation start detection data d to be read usually has some offset amount such as dark charge superimposed thereon, and positive value data other than 0 is read. Therefore, if it is configured to simply continue to add them, the integrated value of the irradiation start detection data d and the like will eventually exceed the set threshold value, even though the radiation imaging apparatus 1 is not irradiated with radiation. The control means 22 will detect the start of radiation irradiation.

  Therefore, for example, every time the irradiation start detection data d is read, a process of calculating a difference Δd from the irradiation start detection data d read in the reading process immediately before the reading process is performed. It can be configured to be performed every time the start detection data d is read.

In this case, for example, when the irradiation start detection data d read in the previous reading process is expressed as dold, the difference Δd is calculated according to the following equation (1).
Δd = d−dold (1)

  Each time the difference Δd is calculated in this way, the calculated difference Δd is added to the integrated value ΣΔd of the difference so far, and the integrated value ΣΔd of the difference obtained by adding the difference Δd is set to the set threshold value Σth. It can be configured to detect that irradiation of radiation is started at a time exceeding

  In addition, as described above, instead of integrating the difference Δd between the read irradiation start detection data d and the irradiation start detection data d read immediately before it, it is also possible to configure as follows. is there.

  That is, each time the reading process of the irradiation start detection data d is performed, the average of the irradiation start detection data d read in the past reading process for a predetermined number of times (for example, 10 times) including the reading process of that time. That is, the moving average dma is calculated.

Further, the irradiation start detection data d read in the reading process of that time and the moving average dma calculated in the previous reading process (that is, read in the past reading process for a predetermined number of times including the previous reading process). A difference Δd from the moving average dma) of the irradiation start detection data d is calculated according to the following equation (2).
Δd = d−dma (2)

  Each time the difference Δd is calculated in this way, the calculated difference Δd is added to the integrated value ΣΔd of the difference so far, and the integrated value ΣΔd of the difference obtained by adding the difference Δd is set to the set threshold value Σth. It can be configured to detect that irradiation of radiation is started at a time exceeding

  When the above-described method is adopted as a method for detecting the start of radiation irradiation, the read-out irradiation start detection data d fluctuates while the radiation imaging apparatus 1 is not irradiated with radiation, and the irradiation start detection data d is changed. The value becomes larger or smaller than the irradiation start detection data dold and moving average dma read out last time.

  For this reason, the difference Δd calculated according to the above equations (1) and (2) becomes a positive value or a negative value. For this reason, the integrated value ΣΔd changes to a value close to zero.

  However, when radiation irradiation to the radiographic imaging apparatus 1 is started, the read value of the irradiation start detection data d is larger than the previously read irradiation start detection data dod and the moving average dma. Therefore, the difference Δd becomes a positive value. For this reason, the integrated value ΣΔd increases.

  When the radiation image capturing apparatus 1 is irradiated with strong radiation, that is, radiation with a large dose rate, for example, as shown in FIG. 9, the irradiation start detection data d to be read is read out before that. The value is much larger than the value of the start detection data d. The value is much larger than the moving average dma.

  For this reason, the difference Δd between the irradiation start detection data d read in the reading process of the time and the irradiation start detection data dold and the moving average dma read out last time becomes a large value, so that it is up to the previous time. The integrated value ΣΔd in the current reading process calculated by adding to the integrated value is also increased at a stretch.

  On the other hand, when the dose rate of the radiation irradiated to the radiographic imaging apparatus 1 is small, the integrated value ΣΔd does not increase at a stretch as described above, but the value of the read irradiation start detection data d is the previous value. Since the read start detection data doold and the moving average dma up to the previous time are often larger, the difference Δd is often a positive value. Therefore, in this case, the integrated value ΣΔd gradually increases.

  Therefore, when the above method is used, the integrated value ΣΔd does not exceed the threshold value Σth before the radiation irradiation to the radiation imaging apparatus 1 is started, but when the radiation irradiation is started, the integrated value ΣΔd increases. Then, the threshold value Σth is exceeded. Therefore, by configuring as described above, it is possible to accurately detect the start of radiation irradiation on the radiographic imaging apparatus 1 even when the radiation dose applied to the radiographic imaging apparatus 1 is very small. .

[Each process after detection]
When the irradiation start of the radiation image capturing apparatus 1 is detected based on the read irradiation start detection data d as described above, the control unit 22 of the scanning drive unit 15 as shown in FIG. A turn-off voltage is applied to all the lines L1 to Lx of the scanning line 5 from the gate driver 15b, so that each TFT 8 is turned off. Then, the charge generated in each radiation detection element 7 due to radiation irradiation is shifted to a charge accumulation state in which the radiation detection element 7 is accumulated.

  Subsequently, the control unit 22 continues the charge accumulation state for a predetermined time, and then sequentially applies an on-voltage from the gate driver 15b to each of the lines L1 to Lx of the scanning line 5 so that each radiation detection element 7 generates a main image. The image data D is read out from the image data D. In FIG. 12, image data D as the main image is described as main image data D.

  Further, the image data D to be read is superimposed with the offset due to the dark charge accumulated in each radiation detection element 7 while the TFT 8 is in the OFF state across the charge accumulation state period. .

Therefore, in subsequent image processing, the offset due to the dark charge is subtracted from the image data D to calculate true image data D ^* based only on the charges generated in each radiation detection element 7 due to the irradiation of radiation. In order to be able to do so, the radiographic image capturing apparatus 1 reads offset data O as offset data O that reads offsets due to dark charges superimposed on the image data D before or after radiographic image capturing. Is configured to be performed.

  In this embodiment, the offset data O reading process is performed by repeating a series of processing sequences up to the reading process of the image data D as the main image (see FIG. 12).

  That is, as shown in FIG. 12, when the reading process of the image data D as the main image is completed, the control unit 22 omits the illustration, but as in the processing sequence shown in FIG. The reading process of data d and the reset process of each radiation detection element 7 are alternately repeated. Then, after shifting to the charge accumulation state, the on-voltage is sequentially applied from the gate driver 15b to the lines L1 to Lx of the scanning line 5 at the same timing as the reading process of the image data D as the main image, thereby detecting each radiation. The offset data O is read from each element 7.

  In the reading process of the offset data O, the radiation image capturing apparatus 1 is not irradiated with radiation. Therefore, since it is not necessary to perform the radiation irradiation start detection process, the timing shown in FIG. 12 is used instead of performing the irradiation start detection data d in the detection line 5d before the offset data O read process. It is also possible to perform a reset process for each radiation detection element 7 in the detection line 5d at the same ON voltage application timing as in FIG.

  As described above, according to the radiographic image capturing apparatus 1 according to the present embodiment, each function of the scanning line 5 and the signal line 6, the scanning drive unit 15, the readout circuit 17, and the like that are already provided in the radiographic image capturing apparatus 1. The radiation image capturing apparatus 1 itself can accurately detect the radiation irradiation start based on the irradiation start detection data d read out before the radiation image capturing.

  For this reason, as described above, it is not necessary to newly provide an X-ray sensor or current detection means in the radiographic image capturing apparatus 1. For example, a space for arranging the X-ray sensor in the radiographic image capturing apparatus 1 is newly provided. It is possible to accurately prevent problems such as deterioration of the S / N ratio of the image data D due to noise generated by the current detection means.

[Image correction processing to repair line defects]
Next, as will be described later, an image correction process for repairing a line defect in the image data D that inevitably occurs when the above-described detection method of the radiographic imaging apparatus 1 according to the present embodiment is employed will be described.

  The image correction processing may be configured to be performed by the console 58 that is an image processing apparatus, or may be configured to be performed by the control unit 22 in the radiation image capturing apparatus 1 itself.

  Further, when this image correction processing is performed by the console 58 that is an image processing apparatus, the image data D and the offset data O read out as described above from the radiographic image capturing apparatus 1 are transferred to the console 58 that is the image processing apparatus. Configured to transmit. Further, when the radiation image capturing apparatus 1 itself is configured to perform image correction processing, the data after the image correction processing is configured to be transmitted to a console 58 that is an image processing apparatus.

  Furthermore, in the present embodiment, the image processing apparatus performs predetermined image processing such as gain correction, defective pixel correction, and gradation processing on the data after the image correction processing for the line defect is performed, thereby obtaining a radiographic image. Although this predetermined image processing is a known technique, the description thereof is omitted.

  Here, a line defect occurring in the image data D and an image correction method for the line defect will be described. In the present embodiment, at least the following two types of line defects may occur in the image data D.

[First line defect]
In the present embodiment, as described above, the irradiation start is detected based on the increase in the read irradiation start detection data d. However, the increase in the read irradiation start detection data d in this way results in a part of useful charges generated by radiation irradiation in each radiation detection element 7 connected to the detection line 5d. That is, it means that a part of the charge to be read out as the image data D as the main image is lost from the inside of each radiation detection element 7 as the irradiation start detection data d before radiographic image capturing.

  Therefore, in the present embodiment, for example, as shown by hatching in FIG. 13, one line defect, that is, one image data D that is not normal exists in a portion corresponding to the detection line 5 d in the image data D. A line-up state is inevitably generated. Such a line defect is hereinafter referred to as a first line defect. Such a first line defect occurs in each portion corresponding to each detection line 5d in the image data D.

  In the present embodiment, as shown in FIG. 8 and the like, the irradiation start detection data d is the sum of the charges discharged to the signal lines 6 from the radiation detection elements 7 connected to the plurality of detection lines 5d. It is read as data corresponding to the value. Therefore, it is not known how much charge is lost from each radiation detection element 7 in the reading process of the irradiation start detection data d.

[Image correction 1 for first line defect]
Therefore, for example, each image data D is read based on the image data D read from each radiation detection element 7 connected to each detection line 5d in the subsequent reading process of the image data D as the main image. The relative ratio of is calculated. Then, by dividing the irradiation start detection data d by the relative ratio, the contribution of the individual radiation detection elements 7 in the irradiation start detection data d (that is, lost from the individual radiation detection elements 7). The data amount corresponding to the charge) can be estimated.

  This is the image data D as the main image to be read from each radiation detection element 7 connected to the detection line 5d, the irradiation start detection data d read at the time of detecting the start of radiation irradiation, and then In this method, the image is corrected and repaired based on the image data D actually read for each radiation detection element 7.

[Image correction for first line defect 2]
Further, each radiation detection element 7 connected to the detection line 5d can be configured to invalidate the image data D read from each radiation detection element 7.

  In such a configuration, it is not necessary to read out the image data D in the detection line 5d. For this reason, as shown in FIG. 12, in the reading process of the image data D as the main image, the illustration is omitted instead of the configuration in which the on-voltage is applied to the detection line 5d and the image data D is read. It is also possible to perform the reading process of the image data D by not applying the on-voltage to the detection line 5d, but skipping the detection line 5d and sequentially applying the on-voltage to the other scanning lines 5. .

  In this case, as shown in FIG. 13, the image data D read from each radiation detection element 5 connected to the scanning lines 5a and 5b adjacent to the detection lines 5d on the detection unit P, respectively. It is possible to configure so as to correct an image using

  Specifically, with respect to one radiation detection element 7 on the detection line 5d, the radiation detection element 7 such as the radiation detection element 7 adjacent in the vertical direction in FIG. Image data D to be read from the radiation detection element 7 on the detection line 5d is generated on the basis of the image data D that has not been read from the radiation detection elements 7 in the vicinity of the element 7 and the image is generated. It can also be configured to correct.

  Note that when the first line defect is corrected in this way, the scanning line 5a and the scanning line 5b need to be adjacent to the detection line 5d as shown in FIG. It becomes. If the first line L1 and the last line Lx of the scanning line 5 shown in FIG. 3 are included in the detection line 5d, the scanning line 5 adjacent to the first line L1 and the last line Lx of the scanning line 5 is displayed. Since there is only one, the image correction process as described above cannot be performed.

  Therefore, when the first line defect is image-corrected as described above (see FIGS. 8, 10, and 11), the detection line 5d includes the scanning line 5 as described above. It is desirable to designate in advance not to include the scanning line 5 of the end portion on the detection unit P like the first line L1 and the last line Lx.

  In addition, when configured as described above, for example, when a radiation image generated based on the image data D or the like is used for medical diagnosis or the like, it is assumed that a lesioned part is captured in the first line defect. Since the image data D of the first line defect portion is invalidated, information on the lesioned portion of the first line defect portion is lost. However, the lesion is usually imaged across a plurality of scanning lines 5.

  Therefore, when a lesioned part is captured in the first line defect, the lesioned part is also captured in the image data D of the scanning line 5 adjacent thereto. Therefore, by correcting the image as described above, it is possible to appropriately prevent the lesion information from being lost from the image data D due to the image correction.

[Second line defect]
On the other hand, in the present embodiment, in addition to the first line defect, there is a possibility that the second line defect occurs for another reason.

  In the example shown in FIG. 12, before the start of radiation irradiation is detected based on the irradiation start detection data d read from each radiation detection element 7 connected to the detection line 5d, it is actually In some cases, radiation irradiation has already started from the radiation source 52 (see FIGS. 6 and 7) to the radiation imaging apparatus 1.

  At that time, when the intensity u of the radiation irradiated from the radiation source 52 does not rise instantaneously as shown in FIG. 14 (A), for example, the rise of the radiation intensity u is slow as shown in FIG. 14 (B). For example, the read irradiation start detection data d gradually increases without increasing instantaneously as shown in FIG. For this reason, there is a case where the radiation imaging apparatus 1 detects the start of radiation irradiation at a time slightly delayed from the actual start of radiation irradiation from the radiation source 52.

  In such a case, the reset process of each radiation detection element 7 (FIG. 12 etc.) is performed after the radiation irradiation is actually started from the radiation source 52 until the radiation imaging apparatus 1 detects the start of radiation irradiation. (See “R”). Then, the reset processing of each radiation detection element 7 is performed after the start of actual radiation irradiation in this way, so that a part of useful charges generated in each radiation detection element 7 due to radiation irradiation as described above. That is, it means that a part of the electric charge to be read out as the image data D as the main image is lost from within each radiation detection element 7.

  In this case, for the reset processing of each radiation detection element 7 after the radiation irradiation from the radiation source 52 is actually started until the radiation imaging apparatus 1 detects the radiation irradiation start. A line defect occurs in each radiation detection element 7 connected to all the scanning lines 5 to which the ON voltage is applied from the gate driver 15b.

  Such a line defect is hereinafter referred to as a second line defect. In such a second line defect, for example, as shown by hatching in FIG. 15, a state in which the line defect appears continuously in a portion corresponding to each scanning line 5 in the image data D. become.

  The first line defect described above inevitably appears, but the second line defect occurs when the intensity u of the radiation irradiated from the radiation source 52 rises instantaneously as shown in FIG. In some cases, only one line defect appears depending on the timing when radiation irradiation to the radiation image capturing apparatus 1 is started.

  Further, when the intensity u of the radiation emitted from the radiation source 52 rises instantaneously, reading processing of the irradiation start detection data d in which the irradiation start is detected by chance, and the radiation detection elements 7 immediately before that are read. When the actual radiation irradiation is started during the reset process, the second line defect may not appear.

  In contrast to the second line defect in which the line defect can appear continuously as described above, the scanning line 5 on which the line defect has occurred is detected on the detection unit P as in the image correction for the first line defect. It is not unimaginable to perform image correction using image data D read from each radiation detecting element 7 connected to the adjacent scanning line 5.

  However, for example, when a radiation image generated based on the image data D or the like is used for medical diagnosis or the like, a lesioned part is photographed in a portion of a line defect that is continuously generated and adjacent thereto. When a lesioned part is not photographed in the part to be processed, the image data D of the part of the line defect is invalidated as in the image correction for the first line defect, and the line defect is detected by the image data D of the part adjacent thereto. If the image data D of this part is corrected, information on the lesioned part taken in the line defect part is completely lost.

  In this case, the effectiveness and reliability of the radiographic image captured by such a radiographic image capturing apparatus 1 is lowered, and at least for the second line defect, the same as the first line defect described above. Application of image correction processing should be avoided. Therefore, it is desirable to apply an image correction processing method different from that for the first line defect to at least the second line defect.

[Image correction for second line defect 1]
Hereinafter, one method of image correction processing applied to the second line defect in the present embodiment will be described.

  As described above, the radiographic image capturing apparatus 1 according to the present embodiment does not exchange signals and the like with the radiation generating apparatus 55 (see FIGS. 6 and 7). It is not possible to recognize at what timing the radiation image capturing apparatus 1 has started irradiation of radiation from the radiation source 52 of the radiation generating apparatus 55.

  For this reason, it is not known which range of scanning lines 5 should be subjected to image correction on the image data D read from each radiation detection element 7 connected thereto. Therefore, it is necessary to analyze the image data D and specify the range of the image data D to be corrected, that is, the range of the scanning line 5.

Therefore, for example, the range of the image data D to be image-corrected, that is, the range of the scanning line 5 can be specified as follows. Although it is possible to configure the image data D itself as a target of image correction processing, in the following, the offset data O is subtracted from the image data D for each radiation detection element 7 according to the following equation (3). A case where the above range is specified for true image data D ^* calculated as described above will be described.
D ^* = DO (3)

In the present embodiment, the calculated true image data D ^* is plotted in the extending direction of the signal line 6 (see FIGS. 2 and 3 etc.) of the radiation imaging apparatus 1 corresponding to each true image data D ^* . The profile of the true image data D ^* formed in this case is analyzed, and the range of the true image data D ^* in which a defect is generated is specified.

Here, each radiation detection element 7 is represented by (m, n) using the line number m of the signal line 6 to which the radiation detection element 7 is connected and the line number n of the scanning line 5, and each radiation detection element 7 is detected. The true image data D ^* calculated from the image data D read from the element (m, n) is represented as D ^* (m, n).

From the true image data D ^* (m, n) calculated as described above, each radiation detection element (connected to a signal line 6 (the line number of the signal line 6 is M)) ( True image data D ^* (M, n) calculated based on the image data D read from M, n) is extracted.

When the extracted true image data D ^* (M, n) is plotted in the order of the line number n of the scanning line 5, the profile of the true image data D ^* (M, n) is obtained. This is a profile of the true image data D ^* (M, n) in the extending direction of the signal line 6 with respect to the signal line 6 of the line number M of the radiographic imaging apparatus 1. Then, by analyzing the profile of the true image data D ^* formed in this way, it is possible to specify the range of the true image data D ^{* in} which a defect has occurred (that is, the line defect range).

However, the true image data D ^* calculated as described above may also vary. Therefore, when the extracted true image data D ^* (M, n) is plotted in the order of the line number n of the scanning line 5, the profile also varies. Even if it is attempted to specify the above range based on the profile, The range may not be properly specified.

Therefore, in this embodiment, the true image data D ^{* (m,} n) calculated as described above for the true image data D ^* aligned in the extending direction of the scanning lines 5 of the radiation image capturing apparatus 1 ^(m , n average value D ^* ave of) (n), i.e., calculates the true image data D ^{* (m} line number n of the same scan line 5, the average value D ^* ave of n) (n) for each scan line 5 To do.

Then, the average value D ^* ave (n) formed when the average value D ^* ave (n) is plotted side by side in the extending direction of the signal line 6 of the radiographic apparatus 1 as shown in FIG. ^* The profile of ave (n) is analyzed, and the range of true image data D ^* in which a defect is generated is specified.

In the case where the profile is analyzed not for the true image data D ^* but for the image data D itself, similarly, the average value Dave () of the image data D (m, n) of the same scanning line 5 with the line number n. It is desirable to calculate n) for each scanning line 5 to form a profile.

When the average value D ^* ave (n) for each scanning line 5 of the true image data D ^* (m, n) (or image data D (m, n), the same applies hereinafter) is calculated in this way, each true value is calculated. Variations included in the image data D ^* (m, n) are canceled out. For this reason, as shown in FIG. 16, a profile having no variation can be obtained, so that it is possible to accurately specify the range of the true image data D ^{* in} which a defect occurs.

Note that, in the graph on the right side of FIG. 16, only the profile of the average value D ^* ave (n) in the vicinity of the range of the true image data D ^* causing the loss is shown enlarged. In addition, when analyzing the profile of the average value D ^* ave (n) and specifying the range of the true image data D ^* in which a defect has occurred, it is desirable to pay attention to the following points.

The true image data D ^* corresponding to the radiation detection element 7 in the portion where the radiation reaches the radiation image capturing apparatus 1 directly without passing through the subject is close to the upper limit value that the true image data D ^* can take. Become. On the other hand, the true image data D ^* of the portion where the subject is photographed is usually a smaller value.

  Further, in the present embodiment, it is configured such that a larger amount of charge than the maximum amount of charge that can be read out by the readout circuit 17 (see FIGS. 3 and 4) can be accumulated in the radiation detection element 7.

  As described above, even if a part of the electric charge flows out from the radiation detection element 7 in the reset process of each radiation detection element 7 before radiographic imaging, the radiation detection of the part where the radiation has directly reached without passing through the subject In the element 7, thereafter, a large amount of charge is generated in the radiation detection element 7, and a charge larger than the maximum charge amount that can be read out by the readout circuit 17 can be accumulated in the radiation detection element 7.

  Therefore, in the radiation detection element 7 where the radiation has directly reached, even if a part of the charge flows out from the radiation detection element 7 due to a reset process or the like before radiographic imaging, the read image data D is eventually read out by the readout circuit. 17 may be an upper limit value that can be output or a value close thereto.

  That is, in the radiation detection element 7 where the radiation has directly reached, even if a part of the charge flows out of the radiation detection element 7 due to a reset process or the like before radiographic image capturing, as long as the read image data D is viewed, the defect is detected. There are cases where image data D having a large value that has not occurred is read out.

Therefore, the true image data D ^* calculated from such image data D is also a value close to the upper limit of values that the true image data D ^* can take, and the true image data D ^* is missing. In some cases, the data may have a large value that does not cause an error.

Then, the average value D of each scanning line 5 of the true image data D of a large value such deficiency does not occur ^{* (m,} n), and the true image data D ^{* (m,} n) as described above ^{* If} it is included in the calculation target of ave (n), the influence of the true image data D ^* (m, n) having a large value with no loss is increased.

Then, the profile of the average value D ^* ave (n) for each scanning line 5 becomes a profile in which the range of the true image data D ^* in which the defect is generated is difficult to understand as shown in FIG. 17, for example, and the profile is analyzed. Even in such a case, it may be difficult to accurately specify the range of the true image data D ^* in which the defect has occurred.

Therefore, in this embodiment, the true image data D ^* corresponding to the radiation detection element 7 in the portion where the radiation has directly reached without passing through the subject is specified, and the true image data D corresponding to the radiation detection element 7 is specified. ^* Is excluded from the calculation target of the average value D ^* ave (n). The specification of the true image data D ^* corresponding to the radiation detection element 7 where the radiation has directly reached without passing through the subject is performed as follows, for example.

As described above, the true image data D ^* corresponding to the radiation detection element 7 where the radiation has directly reached without passing through the subject is an upper limit value that the true image data D ^* can take or a value close thereto. For example, an upper limit value that can be taken by the true image data D ^* or a value close to the upper limit value is determined as a threshold value. For the true image data D ^* exceeding the threshold value, the average value D ^* ave (n) is uniformly set. It is possible to configure so as to be excluded from the target of calculation.

For example, when the true image data D ^* can take a value from 0 to 65535 (= 2 ¹⁶ −1), if the threshold is set to 64000, for example, the true image data D ^* having a value of 64000 or more is uniformly obtained. The average value D ^* ave (n) is excluded from the calculation target.

  As another method, for example, a result of recognition processing of an area where a subject is imaged (hereinafter referred to as subject region recognition processing) performed in order to generate a radiation image by the console 58 as an image processing apparatus. It is also possible to configure to use.

In the subject area recognition processing, for example, as shown in FIG. 18A, each radiation detection element connected to the scanning line 5 of line number N, for example, from the true image data D ^* (m, n). True image data D ^* (m, N) corresponding to (m, N) is extracted. Then, the extracted true image data D ^* (m, N) is plotted in the order of the line number m of the signal line 6.

Then, as shown in FIG. 18 (B), the true image data D ^* corresponding to the radiation detection element 7 of the part where the radiation directly reaches the radiation image capturing apparatus 1 without passing through the subject is the true image data D. ^* Is an upper limit value that can be taken or a value close thereto, but the true image data D ^* of the portion where the subject is photographed is a smaller value.

Therefore, by analyzing this profile, each true image data D ^* (m, N) corresponding to each radiation detection element (m, N) connected to the scanning line 5 of line number N is shown in FIG. As shown in (B), a region Ro (N) where the subject is photographed is determined. Then, by performing this process for each scanning line 5, as shown in FIG. 18C, the region Ro in which the subject is photographed in all the true image data D ^* is determined and recognized. Can do.

In this embodiment, the subject area recognition process is configured to recognize the area Ro where the subject is photographed in all the true image data D ^* .

Therefore, using the result of the subject area recognition process, true image data D ^* (m, n) belonging to an area other than the area Ro where the subject is photographed is calculated as the average value D ^* ave (n). It can be configured to be excluded from the target.

When the average value D ^* ave (n) for each scanning line 5 of the true image data D ^* (m, n) is calculated as described above (see FIG. 16), the average value D ^* ave ( By analyzing the profile of n), the range of the true image data D ^* in which the defect has occurred (that is, the range of the line defect) is specified.

In this profile, the overall of the true image data D ^* of the mean value D ^* ave containing a defect (n) is the average value D ^* ave of the true image data D does not occur a defect ^* (n) It will be out of the trend of various transitions. Therefore, in the present embodiment, for example, the range of true image data D ^* in which a defect is generated is specified as follows.

  The amount of charge accumulated in each radiation detection element 7 by radiation irradiation increases as time passes after the radiation irradiation is actually started. Therefore, the outflow amount from the radiation detection element 7 of the charge accumulated in each radiation detection element 7 by radiation irradiation is reset immediately after the radiation irradiation from the radiation source 52 is actually started. After that, the amount of outflow from each radiation detection element 7 on which reset processing was performed immediately before the control means 22 of the radiation imaging apparatus 1 detects the start of radiation irradiation, rather than the amount of outflow from each radiation detection element 7. There should be many.

  Then, after the radiation imaging apparatus 1 detects the start of radiation irradiation, an off voltage is applied to each scanning line 5 from the gate driver 15b, and each TFT 8 is turned off to shift to a charge accumulation state. (See FIG. 12), there is no outflow of charge from each radiation detection element 7.

Therefore, as shown in FIGS. 16 and 19, there is a large difference between the average values D ^* ave (n) of the true image data D ^* before and after the radiation imaging apparatus 1 detects the start of radiation irradiation. Will occur. Accordingly, the profile of the average value D ^* ave (n) of the true image data D ^* is analyzed, and the reset processing of each radiation detection element 7 is performed immediately before the radiation imaging apparatus 1 detects the start of radiation irradiation. Thus, it is possible to specify the scanning line 5 to which the ON voltage is applied (hereinafter, this scanning line 5 is referred to as a previous line; see Na in FIG. 19).

  In addition, the radiographic imaging apparatus 1 is configured to record the line number n of the scanning line 5 to which the on-voltage is applied when resetting each radiation detection element 7 and immediately before detecting the start of radiation irradiation. It is also possible to store information such as the line number n of the scanning line 5 (that is, the immediately preceding line) to which the ON voltage is applied. When the image correction process is performed by the image processing apparatus (console 58 in the present embodiment), the above information is transmitted from the radiographic image capturing apparatus 1 to the image processing apparatus. As shown in FIG. 19, hereinafter, the line number of this immediately preceding line is Na.

When the immediately preceding line Na is specified as described above, subsequently, the start of radiation irradiation is detected in the profile of the average value D ^* ave (n) of the true image data D ^* as shown in FIG. The line numbers of the line numbers Na-1, Na-2,... To which the on-voltage was applied in order from the scanning line 5 (that is, the immediately preceding line) of the line number Na to which the on-voltage was applied at the time. The average value D ^* ave (n) corresponding to is observed.

First, the absolute value of the difference ΔD ^* ave between D ^* ave (Na) and D ^* ave (Na-1) is calculated, and the absolute value of the difference ΔD ^* ave is set to a small value close to 0 in advance. It is determined whether it is less than the threshold value. In the example of FIG. 19, since the absolute value of the difference ΔD ^* ave between D ^* ave (Na) and D ^* ave (Na-1) is equal to or greater than the threshold, D ^* ave (Na-1) and D ^* The absolute value of the difference ΔD ^* ave of ave (Na−2) is calculated, and it is determined whether or not the absolute value of the difference ΔD ^* ave is less than the threshold value.

As you repeat this process, in the example of FIG. 19, D ^* absolute value of the difference [Delta] D ^* ave the ave (Na-1) and D ^* ave (Na-2) also, and D ^* ave (Na-2) D ^* ave absolute value of the difference [Delta] D ^* ave of (Na-3) also, although both become equal to or higher than the threshold, the threshold value or more D ^* ave and (Na-3) D ^* ave difference [Delta] D ^* ave of (Na-4) The absolute value is below the threshold for the first time.

  In this case, the on-voltage is applied to the scanning line 5 with the line number Na-3 and the reset process of each radiation detection element 7 performed by applying the on-voltage to the scanning line 5 with the line number Na-3. It can be determined that the radiation image capturing apparatus 1 is actually irradiated with radiation from the radiation source 52 (see FIG. 6 and FIG. 7) at the timing between the reset processing of each radiation detection element 7 performed in this manner.

Therefore, in this case, the scanning line 5 with the line number Na-2 is recognized as the first scanning line 5 in which the image data D starts to be deficient. In this case, the range of the true image data D ^{* in} which the defect has occurred (that is, the range of the line defect) is connected to the three scanning lines 5 of line numbers Na-2, Na-1, and Na. It is specified as true image data D ^* corresponding to each radiation detecting element 7.

That is, among the true image data D ^* (m, n), the true image data D ^* (m, Na-2), D ^* (m, Na-1), and D ^* (m, Na) are missing. Is specified as the range of the true image data D ^* .

Note that, as indicated by an arrow A in FIG. 20, the average value D ^* ave (n) is within the range of the true image data D ^* in which a defect has occurred (the range between two alternate long and short dashed lines in the figure). The absolute value of the difference ΔD ^* ave may be less than the threshold value.

Therefore, as described above, the difference ΔD ^* ave is calculated while the line number n of the scanning line 5 is lowered, and the absolute value of the difference ΔD ^* ave between the average values D ^* ave (n) is less than the threshold value. It is also configured to continue the comparison between the absolute value and the threshold value calculation and the difference [Delta] D ^* ave difference [Delta] D ^* ave been.

Then, when it is confirmed that the difference ΔD ^* ave in which the absolute value is less than the threshold value has appeared continuously, it is determined that the difference has fallen out of the range of the true image data D ^* causing the defect, The search process for the range of the true image data D ^{* in} which the defect has occurred is terminated.

On the other hand, when the range of the true image data D ^* causing the defect (in the above example, the range of the three scanning lines 5 of line numbers Na-2 to Na) is specified as described above, The true image data D ^* in the specified range is restored.

For example, in the example shown in FIG. 19, the average value D ^* ave (Na-2) to D ^* ave (Na) specified as the range of the true image data D ^* causing the defect is on the left side in the figure. average value D ^* ave (Na-3) or the average value D ^* ave (Na-4) or each mean value D ^* ave ranging further comprising the average value D ^* ave left (n) in the figure (n of ) Is approximated by a straight line Lap as shown in FIG. That is,
D ^* ap = a × n + b (4)
A straight line approximation to

The average values D ^* ave (Na-2), D ^* ave (Na-1), and D ^* ave (Na) are essentially Na-2, Na-1, It is considered that a × (Na−2) + b, a × (Na−1) + b, and a × Na + b obtained by substituting Na into the above equation (4), respectively.

Then, for each true image data D ^* (m, Na-2) corresponding to each radiation detecting element (m, Na-2) connected to the scanning line 5 of line number Na-2, {a X (Na-2) + b} / D ^* ave (Na-2) is multiplied,
D ^* (m, Na−2) × {a × (Na−2) + b} / D ^* ave (Na−2) (5)
The true image data D ^* corresponding to each radiation detection element (m, Na-2) connected to the scanning line 5 with the line number Na-2 is restored.

Each true image data D ^* (m, Na-1) corresponding to each radiation detection element (m, Na-1), (m, Na) connected to each scanning line 5 of line numbers Na-1, Na ), D ^* (m, Na),
D ^* (m, Na-1) * {a * (Na-1) + b} / D ^* ave (Na-1) (6)
D ^* (m, Na) × {a × (Na) + b} / D ^* ave (Na) (7)
The true image data D ^* corresponding to the radiation detection elements (m, Na-1) and (m, Na) connected to the scanning lines 5 of the line numbers Na-1 and Na are calculated ^. Correct the image.

In this way, the true image data D ^{* in} the range specified as the range of the true image data D ^{* in} which the defect has occurred (that is, the range in which the second line defect has occurred) is converted into a method such as linear approximation. Each can be repaired accurately using. As described above, the image correction for the second line defect can be performed.

[Image correction 2 for second line defect]
As another image correction method, for example, each scanning line 5 (that is, line number Na in the above example) corresponding to a range of true image data D ^{* in} which a defect has occurred in advance is used. Of the scanning lines 5 to 2 to Na), the number of lines from the first scanning line 5 where a defect has started to occur (that is, the scanning line 5 with the line number Na-2 in the above example) to the scanning line 5 to be repaired The information is related to the coefficient to be multiplied by the true image data D ^* corresponding to each radiation detecting element 7 connected to the scanning line 5 to be repaired.

That is, for example, in the first scanning line 5 from the first scanning line 5 where the defect has started to occur (that is, the scanning line 5 with the line number Na-2 in the above example), each radiation connected to the scanning line 5 A coefficient to be multiplied by the true image data D ^* corresponding to the detection element 7 is 1.1, for example. Further, in the second scanning line 5 from the first scanning line 5 where the defect starts to occur (that is, the scanning line 5 with the line number Na-1 in the above example), each radiation detection element connected to the scanning line 5 For example, the coefficient to be multiplied by the true image data D ^* corresponding to 7 is 1.2.

Further, in the third scanning line 5 (that is, the scanning line 5 of the line number Na (that is, the immediately preceding line) in the above example) from the first scanning line 5 at which the defect starts to occur, each of the scanning lines 5 connected For example, the coefficient to be multiplied by the true image data D ^* corresponding to the radiation detection element 7 is 1.3. Such a relationship is configured so that the radiographic image capturing apparatus 1 and the image processing apparatus have the information in advance.

  This relationship is obtained in advance through experiments or the like. In addition, the relationship between the first scanning line 5 where the defect has started to occur and the number of scanning lines 5 is determined based on the detection of the start of radiation irradiation in the radiographic imaging apparatus 1. It is determined appropriately according to the sensitivity and the like.

Then, the profile of the true image data D ^* and the average value D ^* ave (n) is analyzed as described above, and the first scanning line 5 where the defect starts to occur or the true image data D where the defect occurs. ^When the range of ^* is specified, scanning is performed with reference to the above information to each true image data D ^* in the specified range to which the radiation detection element 7 corresponding to the true image data D ^* is connected. Multiply each of the above coefficients assigned to line 5.

In this manner, the true image data D ^{* in} the range specified as the range of the true image data D ^* in which the defect has occurred is accurately restored using the information on the relationship between the scanning line 5 and the coefficient. It becomes possible.

[Image correction 3 for second line defect]
In addition to the above-described method, for example, it is possible to perform a more strict image correction process to restore the true image data D ^* in which a defect has occurred.

For example, the average value D ^* ave for each scanning line 5 of the true image data D ^* (m, n) (or the image data D (m, n) itself; the same applies hereinafter) shown in each of the drawings after FIG. In the calculation process of (n), as described above, the true image data D ^* corresponding to the radiation detection element 7 of the portion where the radiation has directly reached without passing through the subject is specified (FIGS. 18A to 18C). The average value D ^* ave (n) was calculated by excluding the true image data D ^* corresponding to the radiation detecting element 7.

However, the average value D ^* ave (n) for each scanning line 5 is still strongly influenced by the true image data D ^* having a large value. That is, the patient's body, which is the subject, is usually thicker in the vicinity of the center thereof and becomes thinner toward the peripheral portion. For this reason, the amount of transmitted radiation is greater in the peripheral portion than in the vicinity of the center portion of the subject, and the true image data D ^* corresponding to that portion has a value that is greater than the true image data D ^{* in the} center portion. growing.

Therefore, when the average value D ^* ave (n) for each scanning line 5 of the true image data D ^* (m, n) is simply calculated as described above, the true image data D ^* (m , N) becomes an average value D ^* ave (n) in which the influence of the color is deeply reflected. When a relatively large variation occurs in the true image data D ^* (m, n) of the peripheral portion of the subject having a large value, the true image data is in the profile of the average value D ^* ave (n) for each scanning line 5. The variation of D ^* (m, n) is reflected, and for example, as shown in FIGS. 16 and 19, the average value D ^* ave (n) at the line defect portion does not appear clearly. It may become.

Therefore, in the example of the strict image correction processing described below, instead of using the value of the true image data D ^* itself, the normalized image is calculated by dividing the true image data D ^* by the reference value. The true image data D ^* nor is used to specify the range of the true image data D ^* (or image data D) in which a defect occurs.

In this case, as the reference value, for example, any row in the region Ro (for example, see FIG. 18C) where the subject recognized by the subject region recognition processing is taken, that is, any n in the region Ro. rows ^* true image data D ^(m, n) with (hereinafter, this line of reference line.) true image data D ^{* (m,} n) of can be used.

That is, for example, in the region Ro, the position having the longest length in the extending direction of the scanning line 5 (that is, the lateral direction in FIG. 18C) (for example, the upper end portion in the drawing (that is, n = 1) in the figure). It is possible to set the row of part)) as a reference line and each true image data D ^* (m, 1) on the reference line as each reference value.

Further, for example, a row corresponding to the scanning line 5 in the vicinity of the immediately preceding line (see the line Na of the scanning line 5 in FIG. 19) is used as a reference line, and is read from each radiation detection element 7 connected to the scanning line 5. Each true image data D ^* (m, n) calculated based on the output image data D can be used as each reference value.

In this case, among the scanning lines 5 in the vicinity of the immediately preceding line Na, the scanning lines 5 such as the scanning lines 5 with the line numbers Na-2 to Na shown in FIG. Therefore, it should not be selected as the reference line. Therefore, in the above case, the scanning line 5 having a line number n larger than the immediately preceding line Na (for example, the scanning line 5 having any line number n larger than Na in FIG. 19) is used as a reference line, and each radiation connected thereto. It is desirable to use each true image data D ^* (m, n) calculated based on each image data D (m, n) read from the detection element 7 as each reference value.

Then, the normalization processing is performed on each reference value set as described above, that is, on the image data D (m, n) read from each radiation detection element 7 connected to the scanning line 5 of the reference line. based true respective image data D ^{* (m,} n) that is calculated by the true image data D ^{* (m,} n) of the other row (ie you have a same m) in the same column by dividing each Done.

That is, when normal image data D ^* (m, n) is normalized, among the reference values, the same m as the true image data D ^* (m, n) (that is, the line of the signal line 6). The true image data D ^* (m, n) having the number m) is divided by the true image data D ^* (m, n). When normal image data D ^* (M, n) (M ≠ m) in other columns is normalized, among the reference values, the same M as the true image data D ^* (M, n) is used. dividing each true image data ^D * (M, n) the true image data ^D * with (M, n) and having.

In this way, for each true image data D ^* (m, n) in the region Ro, each true image normalized from each reference value and each true image data D ^* (m, n). Data D ^* nor (m, n) is calculated. In the above method, each true image data D ^* (m, n) on the reference line is normalized by being divided by its own value, and therefore each normalized true image on the reference line is normalized. The data D ^* nor (m, n) is 1 respectively.

Then, in the same manner as described above, an average value D ^* nor_ave (n) for each scanning line 5 of the radiographic image capturing apparatus 1 is calculated for each normalized true image data D ^* nor (m, n). Analyzing the profile of the average value D ^* nor_ave (n) formed when they are arranged and plotted in the extending direction of the signal line 6 of the radiographic imaging device 1, the true image data D ^* causing the defect Is configured to identify a range of

Thus, by calculating the average value D ^* nor_ave (n) for each scanning line 5 for each normalized true image data D ^* nor (m, n), each true image data D ^* nor ( The relative weights of variations in values for each of m, n) are equalized. Therefore, for example, as described above, the variation in the true image data D ^* (m, n) is relatively larger in the peripheral portion than in the vicinity of the center portion of the subject, and the average value D in the line defect portion is increased. ^* It is possible to accurately prevent a decrease in ave (n) (see, for example, FIG. 16 and FIG. 19) from appearing clearly.

For example, the profile of the average value D ^* ave (n) of each true image data D ^* (m, n) before normalization is different from the examples shown in FIGS. For example, when the profile is as shown in FIG. 22A, the profile of the average value D ^* nor_ave (n) of each true image data D ^* nor (m, n) after normalization is, for example, The profile is as shown in FIG.

Hereinafter, the profile of the average value D ^* nor_ave (n) of each normalized true image data D ^* nor (m, n) calculated in this way (see FIG. 22B) is analyzed. An example of a technique for identifying the range of true image data D ^* in which a defect has occurred and repairing them will be described.

First, as shown in FIG. 23, there is a possibility that a line defect appears in the profile of the average value D ^* nor_ave (n) of each normalized true image data D ^* nor (m, n). Excludes the portion LD of the scanning line 5, that is, the portion LD including the previous line Na and the predetermined number of scanning lines 5 whose line number is smaller than Na (that is, the predetermined number of scanning lines 5 to which the ON voltage is applied before the previous line Na) Then, a first approximate straight line Lap1 that approximates each average value D ^* nor_ave (n) in a predetermined number of scanning lines 5 before and after the immediately preceding line Na is calculated.

Then, for each line number n including the line number Na of the immediately preceding line, the actual average value D ^* nor_ave (n) is a value on the first approximate straight line Lap1 corresponding to the average value D ^* nor_ave (n). When the value divided by is plotted, for example, a graph as shown in FIG. 24 is obtained. These divided values are the reduction rate DS (n) of the actual average value D ^* nor_ave (n) with respect to the first approximate straight line Lap1.

In FIG. 24 and the following drawings, only the portion related to the immediately preceding line Na and each scanning line 5 whose line number is smaller than Na is shown. Further, in the following processing, a case where processing is performed using the reduction rate DS (n) will be described. However, the normalized true image data D ^* nor () is not approximated by the first approximate straight line Lap1. It is also possible to perform the processing using the average value D ^* nor_ave (n) of m, n) as it is.

  In addition, the decrease rate DS (n) is slightly smaller than 1 in the portion of the scanning line 5 whose line number is about 15 to 5 smaller than the immediately preceding line Na. This is because any object such as a bone or an organ is photographed. It is thought that it is a part that is. That is, this portion is not a portion where a line defect as shown below appears.

  When the decrease rate DS (n) is calculated for each scanning line 5 as described above, subsequently, the decrease rate DS (Na) of the immediately preceding line Na and the radiation image with respect to the calculated decrease rate DS (n). A predetermined number of scanning lines 5 (that is, the immediately preceding line) in which the on-voltage is applied before the immediately preceding line Na and the resetting process of each radiation detecting element 7 is performed in the detection process of the start of radiation irradiation in the imaging apparatus 1. The reduction rate DS (n) of a predetermined number of scanning lines 5) having a line number smaller than Na is linearly approximated by a second approximate straight line Lap2. Hereinafter, the second approximate straight line Lap2 is simply referred to as an approximate straight line Lap2.

Then, as shown in FIG. 25, the predetermined number of the scanning lines 5 is changed and approximated by an approximate straight line Lap2. Specifically, assuming that the predetermined number is four, in this case, the range of the true image data D ^{* in} which the defect has occurred (that is, the range of the line defect) is the line number Na-3 to Na. It is assumed that the true image data D ^* calculated based on the image data D read from each radiation detection element 7 connected to each of the four scanning lines 5 is obtained.

  Then, the reduction rates DS (Na-3) to DS (Na) of the four scanning lines 5 of the line numbers Na-3 to Na selected in this way are approximated by using, for example, the least square method or the like. A straight line approximation is performed with Lap2. To be exact, in this case, (Na-3, DS (Na-3)), (Na-2, DS (Na-2)), (Na-1, DS (Na) on the graph of FIG. -1)) and (Na, DS (Na)) are linearly approximated by an approximate straight line Lap2.

Also, assuming that the values on the approximate straight line Lap2 corresponding to the scanning lines 5 of the line numbers Na-3 to Na are, for example, Lap2 (Na-3) to Lap2 (Na), those values Lap2 (Na− 3) Each scanning line in which each of the reciprocals 1 / Lap2 (Na-3) to 1 / Lap2 (Na) of Lap2 (Na) is assumed to be the above-mentioned range to be repaired is Na-3 to Na 5 is considered to be each repair coefficient for repairing each true image data D ^* calculated based on the image data D read from each radiation detection element 7 connected to each.

  Therefore, the respective restoration factors 1 / Lap2 (Na-3) to 1 / Lap2 (are respectively added to the respective reduction rates DS (Na-3) to DS (Na) of the scanning lines 5 whose line number n is Na-3 to Na. Multiply Na). Then, each repaired decrease rate DS (Na-3) / Lap2 (Na-3) to DS (Na) / Lap2 (Na) should be repaired to a value close to 1.

Then, for each of the four scanning lines 5 with the line numbers Na-3 to Na assumed as the range of the true image data D ^* causing the defect (that is, the range of the line defect), the respective reduction rates restored. The square error (that is, the square of the difference) between DS (Na-3) / Lap2 (Na-3) to DS (Na) / Lap2 (Na) and 1 is calculated. On the other hand, for the other scanning lines 5, the square errors between the original reduction rates DS (n) and 1 are calculated.

  Then, the total value of these square errors is calculated. The total value of the square errors calculated in this way is a value for the approximate straight line Lap2 approximated when the predetermined number is four. Therefore, the total value of the calculated square errors is assigned to the approximate straight line Lap2 when the predetermined number is four.

In this way, the predetermined number of scanning lines 5 assumed as the range of the true image data D ^* in which the defect has occurred (that is, the range of the line defect) is changed to 2, 3, 4,. As shown in FIG. 25, each is approximated by an approximate straight line Lap2.

  Each time the approximate straight line Lap2 is calculated, in the same manner as described above, for the scanning line 5 in the above range, the square error between each of the repaired reduction rates and 1 is calculated, and for the other scanning lines 5 Calculates the square error of each original reduction rate DS (n) and 1. Then, the total value of the square error is calculated and assigned to the approximate straight line Lap2.

Then, as shown in FIG. 26, an approximate straight line Lap2 ^* is extracted from each approximate straight line Lap2 that minimizes the total value of the square errors. If the extracted approximate straight line Lap2 ^* is an approximate straight line approximated for each scanning line 5 with line numbers Na-5 to Na, for example, as shown in FIG. The range of the image data D ^* (that is, the range of line defects) is based on the image data D read from each radiation detection element 7 connected to each scanning line 5 with line numbers Na-5 to Na. The true image data D ^* calculated in this way can be specified.

In this case, as described above, each value Lap2 ^* (Na-5) to Lap2 ^* (Na) on the extracted approximate straight line Lap2 ^* corresponding to each scanning line 5 of line numbers Na-5 to Na. 1 / Lap2 ^* (Na-5) to 1 / Lap2 ^* (Na) are read out from the radiation detecting elements 7 connected to the scanning lines 5 of line numbers Na-5 to Na, respectively. Each restoration coefficient for the true image data D ^* based on the image data D is obtained.

Therefore, the restoration coefficient 1 / Lap2 ^* (Na-5) -1 corresponding to the true image data D ^* for each radiation detection element 7 connected to each scanning line 5 of line numbers Na-5 to Na, respectively. Multiply / Lap2 ^* (Na) to restore each true image data D ^* within the range to be restored and correct the image.

Specifically, the true image data D ^* (m, Na-5) for each radiation detection element 7 (m, Na-5) whose line number n is Na-5 has a repair coefficient 1 / Lap2 ^* ( Similarly, the true image data D ^* (m, Na-4) to D ^* (m, Na) whose line numbers n are Na-4 to Na are multiplied by the restoration coefficient 1 / By multiplying Lap2 ^* (Na-4) to 1 / Lap2 ^* (Na), each true image data D ^* within the range to be restored can be restored and image correction can be performed.

In this way, each true image data D ^* within the range to be repaired is repaired, so that, for example, as shown in FIG. 27, each true image data D ^* within the range to be repaired. On the other hand, it is possible to accurately restore each true image data D ^* by performing more strict image processing.

In the example of the restoration method of the true image data D ^* shown in FIG. 25 and FIG. 26 described above, the case where the reduction rate DS (n) for each scanning line 5 is linearly approximated by the approximate straight line Lap2 has been described. . In actuality, as shown in FIG. 14A, the radiation dose rate u is applied when the radiation source 52 (see FIGS. 6 and 7) is irradiated with radiation. However, it is assumed that it starts up immediately after the start of radiation irradiation.

  That is, in this case, since the dose rate u from the start of radiation irradiation is constant, the charge generated in each radiation detection element 7 of the radiographic imaging apparatus 1 increases in proportion to time t. And since the electric charge which increases in proportion to time t is discharge | released from each radiation detection element 7 by the reset process of each radiation detection element 7 after the irradiation of a radiation is started, a 2nd line defect arises.

Therefore, as shown in FIG. 26 and the like, the decrease in the true image data D ^* in the line defect portion (in the case of FIG. 26, the corresponding decrease in the decrease rate DS (n)) is approximated by the approximate straight line Lap2 or the like. The assumption was made.

  However, the rising characteristics of radiation from the start of radiation irradiation in the radiation source 52 are various, and as shown in FIG. 14A, the radiation dose rate u always rises immediately immediately after the start of radiation irradiation. Not exclusively.

Therefore, when using the radiation source 52 in which the radiation dose rate u does not rise instantaneously immediately after the start of radiation irradiation, the true image data D ^* in the line defect portion is reduced (or the corresponding reduction rate DS (n ) Etc.) instead of approximating with the approximate straight line Lap2 as described above, an appropriate function is set based on the rising characteristics of radiation from the start of radiation irradiation at the radiation source 52, and approximated with the set function. Thus, it is desirable to restore each true image data D ^* .

  As described above, the electric charge generated in each radiation detection element 7 of the radiographic imaging apparatus 1 increases in accordance with the temporal integration value of the dose rate u of the radiation applied to the radiographic imaging apparatus 1.

  Therefore, when setting the above function, if the dose rate u of radiation emitted from the radiation source 52 changes as shown in FIG. 14B, for example, the dose rate u of radiation increases. The scanning line 5 in which the reset processing of each radiation detection element 7 may be performed during the process is a quadratic function, and the reset of each radiation detection element 7 is performed after the dose rate u becomes constant. The scanning line 5 that may have been processed can be configured to be approximated by a linear function (that is, a straight line).

Further, when the temporal variation of the dose rate u of the radiation irradiated from the radiation source 52 takes another form, the temporal integration value of the dose rate u also changes accordingly. In this way, an appropriate function is set based on the rising characteristics of radiation from the start of radiation irradiation in the radiation source 52, approximated by the set function, and each true image data D ^* is restored and image correction is performed. It is desirable to do.

  In addition, when comprised in this facility in the case where a plurality of radiation sources 52 are provided in the facility, the radiation rising characteristics from the start of radiation irradiation are detected for each radiation source 52, etc. It is desirable to set the above function (including the case of an approximate straight line) in the source 52. The radiographic imaging apparatus 1 and the image processing apparatus apply a function corresponding to the radiation source 52 based on which radiation source 52 is obtained by irradiating the radiation of the image data D. The above-described repair process is performed.

If the second line defect is repaired and image correction is performed as in image corrections 1 to 3 for the second line defect, the true image data D ^* in which the second line defect is generated is obtained. The repair coefficient calculated for each line number n of the scanning line 5 is multiplied.

In that case, the profile in the extending direction of the scanning line 5 of the true image data D ^* for each scanning line 5 is a profile as shown in FIG. 18B, for example. Each of the image data D ^* is multiplied by the restoration coefficient determined for the scanning line 5. For this reason, for example, the profile of the true image data D ^* in FIG. 18B only increases as a whole, and the unevenness in the profile is maintained (that is, the unevenness is not flattened).

Therefore, when the lesion part of the patient is photographed in the second line defect part, even if the true image data D ^* is multiplied by the repair coefficient as described above, the lesion part information is thereby obtained. Is not lost from the true image data D ^* . That is, the difference in brightness between the lesion and its surroundings is maintained.

Therefore, if the second line defect is image-corrected as described above, the line defect is appropriately repaired from the radiation image generated based on the image-corrected true image data D ^*. In the case where a lesion is photographed in the second line defect portion, the lesion is properly photographed in the radiation image without being lost from the radiation image. It becomes a state.

If the image corrections 1 to 3 for the second line defect are employed, the image data D and the true image data D ^* can be restored and image correction can be performed so that such a radiation image is generated. Become.

  As described above, according to the radiation image capturing system 50 according to the present embodiment, the radiation image capturing apparatus 1 inevitably appears in the image data D when the radiation irradiation start detection method as described above is employed. The first line defect and the second line defect in which the line defect may appear continuously in the image data D can be accurately repaired and the image can be corrected.

Then, by generating a radiographic image based on the image data D and the true image data D ^* that have been appropriately repaired and corrected in this manner, it is possible to generate an appropriate radiographic image without line defects or the like. It becomes.

When a lesion is reflected in the line defect, it is possible to restore the image data D and the true image data D ^* without losing information on the lesion. Therefore, if a radiographic image is generated using the image data D or the true image data D ^* that has been corrected as described above, the radiation that has been appropriately captured without losing information on the lesion area from the radiographic image. An image can be generated.

  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.

DESCRIPTION OF SYMBOLS 1 Radiation imaging device 5 Scanning line 5a, 5b Adjacent scanning line 5d Detection line (a plurality of scanning lines designated in advance)
6 Signal line 7 Radiation detection element 8 TFT (switch means)
15 Scanning drive means 15b Gate driver 17 Reading circuit 22 Control means 41 Antenna device (communication means)
50 Radiation imaging system 58 Console (image processing device)
D Image data d Irradiation start detection data L1 First line of the scanning line 5 (scanning line of the end portion on the detection unit)
Last line of Lx scanning line 5 (scanning line at the end on the detection unit)
P detector r small area

Claims (7)

A plurality of scanning lines and a plurality of signal lines arranged so as to intersect with each other, and a plurality of radiation detection elements arranged in a two-dimensional manner in each small region partitioned by the plurality of scanning lines and the plurality of signal lines A detection unit comprising:
A scanning driving means comprising a gate driver for switching on and applying an on voltage and an off voltage to each scanning line;
Switch means connected to each of the scanning lines and causing the signal lines to discharge charges accumulated in the radiation detection element when an on-voltage is applied;
A readout circuit that converts the electric charge emitted from the radiation detection element into image data and reads the image data;
Control means for controlling at least the scanning drive means and the readout circuit to perform readout processing of the image data from the radiation detection element;
With
The control means includes
Prior to radiographic imaging, an on-voltage is applied from the gate driver to one or a plurality of the scanning lines designated in advance among all the scanning lines connected to the gate driver of the scanning driving means. Read processing for reading irradiation start detection data, and reset processing of each radiation detection element performed by sequentially applying an on-voltage from the gate driver to one or a plurality of the scanning lines other than the plurality of scanning lines designated in advance And repeatedly
A radiographic imaging apparatus that detects the start of radiation irradiation based on the read irradiation start detection data.   The radiation according to claim 1, wherein the plurality of scanning lines designated in advance are designated in advance for each of a predetermined number of the scanning lines among the scanning lines provided on the detection unit. Image shooting device.   3. The radiographic imaging apparatus according to claim 1, wherein the plurality of scanning lines designated in advance are designated in advance so as not to include the scanning lines at the end portions on the detection unit. .   The control unit is configured to scan the image data read from the radiation detection elements connected to the plurality of scanning lines designated in advance on the detection unit, respectively, adjacent to the scanning lines. 4. The radiographic image capturing apparatus according to claim 1, wherein image correction is performed using the image data read from each of the radiation detection elements connected to a line. 5.   The control means analyzes the profile of the image data in the extending direction of the signal line on the detection unit, and the reset processing of each radiation detection element is performed while radiation is being emitted. The radiographic image capturing apparatus according to claim 4, wherein a range of the image data causing a defect is specified, and the image data of the specified range is corrected. The radiographic imaging device according to any one of claims 1 to 3, comprising a communication unit;
An image processing device that generates a radiographic image based on the image data transmitted from the radiographic imaging device via the communication unit;
With
The image processing apparatus scans the image data read from the radiation detection elements connected to the plurality of scanning lines designated in advance in the radiation imaging apparatus on the detection unit. A radiographic imaging system, wherein image correction is performed using the image data read from each of the radiation detection elements connected to the scanning line adjacent to the line.   The image processing device analyzes a profile of the image data in the extending direction of the signal line on the detection unit of the radiographic imaging device, and resets each radiation detection element while radiation is being applied. The radiographic image capturing system according to claim 6, wherein a range of the image data in which a defect has occurred due to processing is specified, and the image data in the specified range is subjected to image correction.

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