Radiation imaging device, radiation imaging system, processing device, processing method, and program

Abstract

This technology provides advantages for improving the performance of radiation imaging devices while suppressing the effects of crosstalk. [Solution] A radiation imaging apparatus comprising a pixel array in which multiple pixels are arranged in each column to form multiple columns, and a processing circuit for processing signals read from the pixel array via multiple signal lines, wherein the processing circuit generates a correction value for each column by multiplying the integrated or average value of the signal values ​​of multiple first signals read from the multiple pixels arranged in that column by a crosstalk correction coefficient, and then generates multiple second signal values ​​for a radiation image by subtracting the correction value from each of the signal values ​​of the multiple first signals, the coefficient being common to each column.

Description

Technical Field

[0001] The present invention relates to a radiation imaging apparatus, a radiation imaging system, a processing apparatus, a processing method, and a program.

Background Art

[0002] As an imaging apparatus used for medical image diagnosis and non-destructive inspection, a radiation imaging apparatus including a radiation detection panel in which pixels combining a conversion element that converts radiation into charge and a switching element such as a thin film transistor (TFT) are arranged in an array is widely used. Patent Document 1 discloses a driving method for a radiation imaging apparatus that suppresses the influence of crosstalk superimposed on a signal line when reading a signal from a pixel. Specifically, an operation of reading a signal with the switching element of the pixel from which the signal is read in a conductive state and an operation of reading a signal in a non-conductive state are repeated, and the influence of crosstalk is suppressed by subtracting the signal value obtained in the non-conductive state from the signal value obtained in the conductive state.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the operation shown in Patent Document 1, the number of operations for reading a signal increases, and it may be difficult to improve the performance of a radiation imaging apparatus such as an improvement in frame rate and a reduction in power consumption.

[0005] An object of the present invention is to provide a technique advantageous for improving the performance of a radiation imaging apparatus while suppressing the influence of crosstalk.

Means for Solving the Problems

[0006] In view of the above problems, an embodiment of the present invention provides a radiation imaging apparatus comprising: a pixel array in which a plurality of pixels are arranged in each column to constitute a plurality of columns; and a processing circuit for processing signals read from the pixel array via a plurality of signal lines, wherein the processing circuit generates a correction value for each column by multiplying the integrated value or average value of the signal values ​​of a plurality of first signals read from a plurality of pixels arranged in the column by a crosstalk correction coefficient, and then generates a plurality of second signals for a radiation image by subtracting the correction value from each of the signal values ​​of the plurality of first signals, wherein the coefficient is common to each column. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a technology that is advantageous for improving the performance of radiation imaging devices while suppressing the effects of crosstalk. [Brief explanation of the drawing]

[0008] [Figure 1] This figure shows an example configuration of a radiation imaging system using the radiation imaging device of this embodiment. [Figure 2] Figure 1 shows an example of the configuration of the radiation detection panel of the radiation imaging device. [Figure 3] Figure 1 shows an example of the pixel configuration of a radiation imaging device. [Figure 4] Figure 1 shows an example of the operation of a radiation imaging system. [Figure 5] Figure 1 illustrates the mechanism of crosstalk generation in a radiation imaging device. [Figure 6] Figure 1 shows the generation flow of crosstalk correction coefficients for the radiation imaging device. [Figure 7] Figure 1 illustrates the generation of crosstalk correction coefficients for the radiation imaging device. [Figure 8] A flowchart illustrating the crosstalk correction for the radiation imaging device shown in Figure 1. [Figure 9] Figure 1 illustrates the crosstalk correction for the radiation imaging device. [Figure 10]Figure 1 shows the generation flow of crosstalk correction coefficients for the radiation imaging device. [Figure 11] This diagram illustrates the wave tail of radiation incident on the radiation imaging device shown in Figure 1. [Figure 12] Figure 1 illustrates the relationship between the imaging conditions of the radiation imaging device and the crosstalk correction coefficient. [Figure 13] A flowchart illustrating the crosstalk correction for the radiation imaging device shown in Figure 1. [Modes for carrying out the invention]

[0009] The embodiments will be described in detail below with reference to the attached drawings. Note that the following embodiments do not limit the invention as defined in the claims. While the embodiments describe multiple features, not all of these features are essential to the invention, and the features may be combined in any way. Furthermore, in the attached drawings, identical or similar configurations are given the same reference numerals, and redundant descriptions are omitted.

[0010] Furthermore, the radiation in this disclosure may include not only alpha rays, beta rays, and gamma rays, which are beams created by particles (including photons) emitted by radioactive decay, but also beams with energy of equal or greater magnitude, such as X-rays, particle beams, and cosmic rays.

[0011] A radiation imaging apparatus according to an embodiment of the present disclosure will be described with reference to Figures 1 to 13. Figure 1 is a diagram showing an example configuration of a radiation imaging system 100 including a radiation imaging apparatus 110 of this embodiment. The radiation imaging system 100 is configured to generate an electrical radiation image by electrically capturing an optical image formed by radiation. The radiation imaging system 100 may include, for example, a radiation imaging apparatus 110, a computer 120, a display 114, an exposure control device 130, and a radiation generator 140.

[0012] The radiation generator 140 starts irradiating the radiation 160 in accordance with the irradiation command (radiation command) from the irradiation control device 130. The radiation 160 irradiated from the radiation generator 140 passes through the subject 150 and enters the radiation imaging device 110. The radiation generator 140 also stops irradiating the radiation 160 in accordance with the stop command from the irradiation control device 130.

[0013] The radiation imaging device 110 may include a radiation detection panel 111, a control circuit 112, and an image generation circuit 113. The radiation detection panel 111 generates data of a radiation image corresponding to the radiation 160 incident on the radiation imaging device 110 and transmits it to the computer 120. The control circuit 112 controls the operation of the radiation detection panel 111.

[0014] The control circuit 112 may be a PLD (Programmable Logic Device) such as an FPGA (Field Programmable Gate Array), or may be composed of a dedicated circuit such as an ASIC (Application Specific Integrated Circuit). Instead of this, the control circuit 112 may be composed of a combination of a general-purpose processing circuit such as a processor and a storage circuit such as a memory. In this case, the function of the control circuit 112 may be realized by the general-purpose processing circuit executing the program stored in the storage circuit.

[0015] The image generation circuit 113 stores the signal supplied from the radiation detection panel 111 in the memory, and generates signal data for a radiation image based on this signal. Details of the method for generating the radiation image will be described later. The image generation circuit 113 transmits the generated signal data for the radiation image to the computer 120.

[0016] The computer 120 may include a control unit that controls the radiation imaging device 110 and the exposure control device 130, and a reception unit that receives signal data for a radiation image from the radiation imaging device 110. Further, the computer 120 may include a signal processing unit that processes the signal data for the radiation image obtained by the radiation imaging device 110. Using the signal data processed by the computer 120, for example, a radiation image may be displayed on the display 114. The control unit, the reception unit, and the signal processing unit may each be configured by a dedicated circuit, similar to the control circuit 112, or may be configured by a combination of a general-purpose processing circuit and a storage circuit.

[0017] In one example, the exposure control device 130 includes an exposure switch. When the exposure switch is pressed (turned on) by the user, an exposure command is sent to the radiation generator 140, and a start notification indicating the start of radiation irradiation is sent to the computer 120. Upon receiving the start notification, the computer 120 notifies the control circuit 112 of the radiation imaging device 110 of the start of radiation irradiation in response to the start notification. When the exposure control device 130 and the computer 120 are not synchronously connected, the radiation detection panel 111 may detect the start of irradiation of the radiation 160 based on the pixel signal.

[0018] FIG. 2 shows a configuration example of the radiation detection panel 111 disposed in the radiation imaging device 110. The radiation detection panel 111 may include, for example, a pixel array 200, a driving circuit 210, a readout circuit 220, a buffer circuit 230, and an analog-to-digital (AD) converter 240. In the present embodiment, the radiation detection panel 111 is divided vertically as shown in FIG. 2, and a set including the pixel array 200, the driving circuit 210, the readout circuit 220, the buffer circuit 230, and the AD converter 240 is arranged symmetrically in two sets. Hereinafter, when referring to the reference numerals of the configuration of the upper set, a prime (') may be appended to the end of each reference numeral of the configuration of the lower set. When the upper and lower sets are not particularly distinguished, it is simply denoted as the pixel array 200, and when the upper and lower sets are distinguished, it is expressed as the pixel arrays 200 and 200'. The driving circuit 210 and the readout circuit 220 function as peripheral circuits of the pixel array 200.

[0019] The pixel array 200 is arranged such that, for example, multiple pixels P are placed in each column to form multiple columns. The multiple pixels P are driven by multiple drive lines Vg1 to Vgm, which are placed in each row, and output signals via multiple signal lines Sig1 to Sign (upper side in Figure 2) and multiple signal lines Sig'1 to Sig'n (lower side in Figure 2). The pixel array 200 is arranged with multiple columns and multiple signal lines Sig1 to Sign and Sig'1 to Sig'n such that one of the signal lines Sig1 to Sign and Sig'1 to Sig'n corresponds to one of the multiple columns. In addition, a bias line Bs is connected to the multiple pixels P to supply a bias potential. The drive lines Vg1 to Vgm and the signal lines Sig1 to Sign and Sig'1 to Sig'n may be simply referred to as drive line Vg and signal line Sig, respectively, unless they are specifically referring to drive lines and signal lines. As shown in Figure 2, the signal line Sig is separated into the upper pixel array 200 and the lower pixel array 200'. Here, the column direction in which multiple pixels P are arranged is the vertical direction in Figure 2. The row direction is the horizontal direction in Figure 2. Therefore, each of the multiple signal lines Sig is arranged along the column direction (vertical direction in Figure 2). Also, each of the multiple drive lines Vg is arranged along the row direction (horizontal direction in Figure 2).

[0020] Multiple pixels P are arranged to form multiple rows and multiple columns. As described above, the row direction is the horizontal direction in Figure 2, and the column direction is the vertical direction in Figure 2. As shown in Figure 2, the pixel columns are divided into an upper pixel array 200 and a lower pixel array 200'. In one example, the radiation detection panel 111 has dimensions of 9 inches, and the pixel arrays 200 and 200' that make up the radiation detection panel 111 may have 1000 columns of pixels P and a total of 1000 rows of pixels P, with 500 rows each on the upper (pixel array 200) and lower (pixel array 200'). In this embodiment, an example is shown in which two pixel arrays 200 and 200' are arranged in one radiation detection panel 111, but there may be one pixel array or three or more.

[0021] In Figure 2, the two pixel arrays 200 and 200' are arranged vertically, and each row is referred to as the mth row (where m is an integer between 1 and 1000) from the top. Similarly, each column of the pixel arrays 200 and 200' is referred to as the nth column (where n is an integer between 1 and 1000) from the left side of Figure 2. Each pixel P can be composed of a combination of one conversion element C and one switch element S. A pixel P located in the ith row and jth column of the pixel array 200 is denoted as pixel P(i,j). The conversion element C and switch element S contained within pixel P(i,j) are denoted as conversion element C(i,j) and switch element S(i,j), respectively. For example, pixel P(1,2) is a pixel P located in the 1st row and 2nd column.

[0022] The conversion element C generates and stores an electric charge corresponding to the radiation incident on it. The conversion element C can store not only the charge corresponding to radiation, but also the charge generated by dark currents and other factors. The fact that the conversion element C of a pixel P generates and stores charge is sometimes expressed as the pixel P generating and storing charge.

[0023] The switch element S is positioned between the conversion element C and the signal line Sig corresponding to the conversion element C. For example, switch elements S(1,1) to S(m,1) are positioned between multiple conversion elements C(1,1) to C(m,1) and the signal line Sig1, respectively. When the switch element S is turned on, the connection between the conversion element C and the signal line Sig becomes conductive, and the charge obtained by the conversion element C (for example, the charge stored in the conversion element C) is transferred to the signal line Sig. The conversion element C may be, for example, an MIS-type photodiode made mainly of amorphous silicon, positioned on an insulating substrate such as a glass substrate. Alternatively, the conversion element C may be a PIN-type photodiode. It may also be configured as an indirect type in which radiation is converted into detectable light by a photodiode using a scintillator, and this light is then detected by the photodiode. In an indirect type conversion element C, the scintillator may be shared by multiple pixels P. Alternatively, the conversion element C may be configured as a direct type in which radiation is directly converted into electric charge.

[0024] The switching element S may consist of a transistor, such as a thin-film transistor (TFT) having a control terminal (gate) and two main terminals (source and drain). The conversion element C has two main electrodes. One main electrode of the conversion element C is connected to one of the two main terminals of the switching element S, and the other main electrode of the conversion element is connected to a bias power supply Vs via a common bias line Bs. The bias power supply Vs generates a bias potential.

[0025] The control terminal of the switch element S for the first row of pixel P is connected to the drive line Vg1. The control terminal of the switch element S for the second row of pixel P is connected to the drive line Vg2. The same applies to the control terminals of the switch elements S for the 3rd to mth rows of pixel P.

[0026] The drive circuit 210 supplies drive signals to the control terminals of the switch elements S of each pixel P via drive lines Vg, according to the drive signals supplied from the control circuit 112. The drive signals include an ON signal (a high-level signal in the following description) to turn on the switch elements S and an OFF signal (a low-level signal in the following description) to turn off the switch elements S. The drive circuit 210 includes, for example, a shift register, which performs a shift operation according to a control signal (for example, a clock signal) supplied from the control circuit 112.

[0027] Selecting a pixel P is expressed as supplying an ON signal (i.e., a high-level drive signal) to that pixel P. In other words, the drive signal is a signal used to select one of several pixels P. The same drive signal is supplied to multiple pixels P within the same pixel row. Selecting multiple pixels P within a row is expressed as selecting that row.

[0028] The readout circuit 220 amplifies and reads the signal appearing on the signal line Sig by selecting pixel P. This signal is based on the charge accumulated in the conversion element C. Reading out the signal based on the charge accumulated in the conversion element C of pixel P is referred to as reading out the signal based on the charge accumulated in pixel P.

[0029] The readout circuit 220 may include one amplifier circuit 221 for each signal line Sig. In the example shown in Figure 2, the upper and lower pixel arrays 200, 200' each have n signal lines Sig. Therefore, the readout circuits 220, 220' each include n amplifier circuits 221. The amplifier circuit 221 includes, for example, an integral amplifier 222, a variable amplifier 223, a switch element 224, a capacitor 225, and a buffer circuit 226. The switch element 224 and the capacitor 225 constitute a sample-and-hold circuit. The integral amplifier 222 includes, for example, an operational amplifier, an integral capacitor connected in parallel between the inverting input terminal and the output terminal of the operational amplifier, and a reset switch. A reference potential is supplied to the non-inverting input terminal of the operational amplifier from a reference power supply Vref. When the reset switch is turned on in response to the control signal RC (reset pulse) supplied from the control circuit 112, the integral capacitor is reset and the potential of the signal line Sig is reset to the reference potential. The variable amplifier 223 amplifies the signal output from the integrating amplifier 222 at a set amplification factor. The sample-and-hold circuit samples and holds the signal output from the variable amplifier 223. The on / off state of the switch element 224 constituting the sample-and-hold circuit is controlled by the control signal SH supplied from the control circuit 112. The buffer circuit 226 buffers (impedance-converts) the signal output from the sample-and-hold circuit and outputs it.

[0030] The readout circuit 220 may also include a multiplexer 227 that selects and outputs signals from multiple amplifier circuits 221 in a predetermined order. The multiplexer 227 may include, for example, a shift register, which performs a shift operation according to a control signal (e.g., a clock signal) supplied from the control circuit 112. This shift operation selects one signal from among the signals output from the multiple amplifier circuits 221.

[0031] The buffer circuit 230 buffers (impedance converts) the signal output from the multiplexer 227. The AD converter 240 converts the analog signal output from the buffer circuit 230 into a digital signal. The output of the AD converter 240, i.e., the pixel signal, is transmitted to the image generation circuit 113.

[0032] Figure 3 schematically shows an example of the cross-sectional structure of a single pixel P. The pixel P may be formed on an insulating substrate 301, such as a glass substrate. The pixel P includes a conductive layer 302, an insulating layer 303, a semiconductor layer 304, an impurity semiconductor layer 305, and a conductive layer 306 on the substrate 301. The conductive layer 302 constitutes the control terminal (gate) of the transistor (e.g., TFT) that constitutes the switching element S. The insulating layer 303 is arranged to cover the conductive layer 302. The semiconductor layer 304 is arranged on the portion of the conductive layer 302 that constitutes the gate, via the insulating layer 303. The impurity semiconductor layer 305 is arranged on the semiconductor layer 304 to constitute the two main terminals (source and drain) of the transistor that constitutes the switching element S. The conductive layer 306 constitutes wiring patterns connected to the two main terminals (source and drain) of the transistor that constitutes the switching element S. A portion of the conductive layer 306 constitutes a signal line Sig, while another portion constitutes a wiring pattern for connecting the switching element S to the conversion element C.

[0033] Pixel P may further include an interlayer insulating film 307 covering the insulating layer 303 and the conductive layer 306. The interlayer insulating film 307 is provided with a contact plug 308 for connecting to the conductive layer 306 (switch element S). On top of the interlayer insulating film 307, pixel P may further include a conductive layer 309, an insulating layer 310, a semiconductor layer 311, an impurity semiconductor layer 312, a conductive layer 313, a protective layer 314, an adhesive layer 315, and a scintillator 316 in this order. These layers constitute an indirect type conversion element C. The conductive layer 309 and the conductive layer 313 constitute the lower electrode and the upper electrode of the photoelectric conversion element that constitutes the conversion element C, respectively. The conductive layer 313 is made of, for example, a transparent conductive material. The conductive layer 309, the insulating layer 310, the semiconductor layer 311, the impurity semiconductor layer 312, and the conductive layer 313 constitute an MIS type photodiode as a photoelectric conversion element. The impurity semiconductor layer 312 is formed, for example, from an n-type impurity semiconductor layer. The conversion element C is not limited to an MIS-type photodiode, but may be a PN-type or PIN-type photodiode, for example. For the scintillator 316, materials such as gadolinium-based materials or cesium iodide are used. The scintillator 316 converts the incident radiation into light detectable by the photodiode.

[0034] Alternatively, the conversion element C may be configured as a direct-type conversion element that directly converts incident radiation into electric charge. Examples of direct-type conversion elements C include those whose main materials are amorphous selenium, gallium arsenide, gallium phosphorus, lead iodide, mercury iodide, cadmium telluride, and zinc cadmium telluride.

[0035] In the example shown in Figure 3, in the orthogonal projection onto the surface of the substrate 301 on which the pixel array 200 is formed, each of the multiple signal lines Sig is arranged to overlap with a portion of the conversion element C. This configuration is advantageous because it allows for a larger area of ​​the conversion element C in each pixel P.

[0036] Referring to Figure 4, an example of the operation of the radiation imaging system 100 of this embodiment will be described. The upper part of Figure 4 shows the timing chart, and the lower part of Figure 4 shows the signal processing flow. The operation shown in Figure 4 can be started, for example, by a user pressing the exposure switch. The operation of the radiation imaging system 100 is controlled by a computer 120. The operation of the radiation imaging device 110 is performed by a control circuit 112 under the control of the computer 120. Specifically, the control circuit 112 performs the operation shown in Figure 4 by controlling the drive circuit 210 and the readout circuit 220. In the following description, when the control circuit 112 causes a specific operation to be performed by controlling the drive circuit 210 or the readout circuit 220, it may simply be said that the control circuit 112 performs a specific operation.

[0037] In the timing chart of Figure 4, "Vg1" to "Vg8" indicate the levels of the drive signals supplied from the drive circuit 210 to each drive line Vg1 to Vg8. In the example shown in Figure 4, for simplicity, the case where the pixel array 200 contains 8 rows of pixels is described, but the number of pixel rows is not limited to this. For example, the pixel arrays 200 and 200' may have 1000 rows of pixels as described above.

[0038] In the timing chart of Figure 4, "Period" represents the period during which a specific operation is performed. Imaging by the radiation imaging device 110 includes an accumulation period during which an accumulation operation is performed and a readout period during which a readout operation is performed. During the accumulation period, the control circuit 112 does not select any of the multiple pixels P included in the pixel array 200. Specifically, the drive circuit 210 maintains a state in which an off signal is supplied to each of the drive lines Vg1 to Vg8. As a result, the charge generated in each conversion element C is accumulated in the conversion element C.

[0039] During the readout period, the control circuit 112 selects each of the multiple pixels P included in the pixel array 200 and reads a signal from the selected pixel P. Specifically, the drive circuit 210 supplies ON signals to drive lines Vg1 to Vg8 one by one in sequence. First, the drive circuit 210 supplies an ON signal only to drive line Vg1. This turns on the switch element S(1, j) (j=1, ..., n), and conducts between the conversion element C(1, j) and the signal line Sigj. As a result, a signal corresponding to the charge accumulated in the conversion element C(1, j) is read out to the signal line Sigj. Next, the drive circuit 210 supplies an ON signal only to drive line Vg2. This turns on the switch element S(2, j), and conducts between the conversion element C(2, j) and the signal line Sigj. As a result, a signal corresponding to the charge accumulated in the conversion element C(2, j) is read out to the signal line Sigj. The drive circuit 210 repeats this operation up to the drive line Vg8, and the signals based on the charge accumulated in each conversion element C are read out by the read circuit 220 via the signal line Sigj. In the following description, performing a read operation for multiple pixels P means performing a read operation for each of the multiple pixels P.

[0040] The control circuit 112 captures moving images (i.e., captures multiple radiation images). The control circuit 112 alternately performs accumulation and readout operations. As shown in Figure 4, it performs an accumulation operation and then reads out signals based on the charges accumulated in multiple pixels P. As shown in Figure 4, when acquiring radiation images continuously, radiation may be continuously irradiated (the "radiation" is continuously in a high state). However, it is not limited to this, and radiation may be irradiated in a pulsed manner according to the acquisition of each radiation image.

[0041] The image generation circuit 113 functions as a processing circuit that processes signals read out from each of the multiple pixels P included in the pixel array 200 via multiple signal lines Sig. For example, it generates signal data X for a radiographic image based on the signals read out from each of the multiple pixels P. The signal data X is represented as an m x n matrix, and the signal read out from pixel P(i, j) becomes the (i, j) component of this matrix.

[0042] Next, with reference to Figure 5, the crosstalk occurring in the pixel array 200 will be explained. In this embodiment, we will explain the case where the radiation emitted from the radiation generator 140 is continuous in time, as shown in Figure 4. Also, in Figure 5, the signal line Sig is drawn horizontally, unlike in Figure 2. When the radiation emitted from the radiation generator 140 is continuous in time, radiation is emitted to all pixels P even during the readout period in which signals are read from each pixel P, and the amount of charge accumulated in the conversion element C may change. Therefore, as shown in Figure 5, charge I flows to the signal line Sig via the coupling capacitance CC (parasitic capacitance between the node connecting the conversion element C and the switch element S, and the signal line Sig). Figure 5 shows an example of the j-th column pixel P when the switch element S in the 1000th row is in the ON state. As shown in Figure 5, the signals from the conversion elements C of pixels P in rows 501 to 999, which are connected to the signal line Sig'j, are superimposed as crosstalk on the signal output from the 1000th row pixel P. Similarly, in the other rows, the signals of the pixels P (conversion elements C) located in each row connected to the same signal line Sig are superimposed on the signals of the pixels P (conversion elements C) in the selected row.

[0043] Next, with reference to Figures 6 and 7(a) to 7(c), a method for generating crosstalk correction coefficients according to this embodiment, which suppresses the effects of such crosstalk, will be described. First, when the operation of generating crosstalk correction coefficients is started, in S101 shown in the flowchart of Figure 6, before radiation irradiation, an object (jig) for determining the crosstalk correction coefficients is positioned so that a part of the radiation detection panel 111 (pixel array 200, 200') is irradiated with radiation. For example, a user sets the computer 120 to perform the operation of generating crosstalk correction coefficients via an interface attached to the computer 120. In accordance with this setting, the computer 120 may display a screen on the interface instructing the user to place the object for determining the crosstalk correction coefficients at a predetermined position on the radiation detection panel 111. Thereafter, the user can perform the work according to the screen instructing the placement of the object. Here, in the operation of generating crosstalk correction coefficients, a part of the radiation detection panel 111 (pixel array 200, 200') that is irradiated with radiation may be referred to as the irradiation area. The object has a region that generally transmits radiation and a region that generally shields radiation. In this embodiment, as shown in Figure 7(a), the object may be a shielding plate with an opening in part, to which radiation is irradiated in a portion of the pixel array 200 (irradiated region) and to which radiation is generally shielded in the other portion of the pixel array 200 and the pixel array 200'.

[0044] After the subject is positioned, the user presses a button for generating correction coefficients on the interface attached to the computer 120. At this time, the computer 120 may display a screen to confirm whether or not the subject has been positioned on the interface. When the button for generating correction coefficients is pressed, the computer 120 controls the exposure control device 130, and radiation is continuously irradiated from the radiation generator 140 towards the radiation imaging device 110. The radiation imaging device 110 generates a signal using the method described above with reference to Figure 4.

[0045] Next, in S102, the radiation imaging device 110 transmits the signals generated by the radiation detection panel 111 (pixel arrays 200, 200') to the image generation circuit 113, which functions as a processing circuit for processing the signals, via the readout circuit 220. The signals output from each pixel P in the pixel array 200 and the signals output from each pixel P in the pixel array 200' are read out to the readout circuit 220 via different signal lines Sig, as shown in Figure 2.

[0046] After reading the signal, the process transitions to S103. The image generation circuit 113 averages the received signal row by row across the width of the regions of interest (ROI) 1, ROI 2, and ROI 3 shown in Figure 7(a), and generates the vertical line profile shown in Figure 7(b). The row width of ROI 1 to 3 can be set to be equal to or narrower than the width of the illumination area, for example. For example, in the configuration shown in Figure 7(a), the row width of ROI 1 to 3 is set to be from the 250th column to the 750th column. In that case, the image generation circuit 113 calculates the average value of the signal output from the pixels P from the 250th column to the 750th column in each row from row 0 to row 1000. Next, the image generation circuit 113 calculates the average value of the signal output from the pixels P located in each region of ROI 1 to 3.

[0047] Here, the pixels P located in ROI1 consist of pixels P located in the irradiated area and pixels P located not in the irradiated area but connected to the same signal line Sig (in the example above, signal lines Sig250 to Sig750) as the pixels P located in the irradiated area. Pixels P located not in the irradiated area but connected to the same signal line Sig as the pixels P located in the irradiated area may experience an increase in signal value due to crosstalk, as shown in Figures 7(a) and 7(b), even though they are not irradiated with radiation. The region where these pixels P are located is sometimes referred to as the crosstalk region, as shown in Figure 7(b). The pixels P located in ROI2 are the pixels P located in this crosstalk region. It can also be said that the pixels P located in ROI2 are pixels P located not in the irradiated area but connected to the same signal line Sig as the pixels P located in the irradiated area. The pixels P located in ROI3 are pixels P that are not located in the illumination region and are connected to a different signal line Sig from the pixels P located in the illumination region among the multiple signal line Sig. In this embodiment, ROI3 is set in the pixel array 200'. In the example above, the pixels P located in ROI3 are pixels P connected to signal line Sig'250~750 of the pixel array 200'. In other words, the pixels P located in ROI3 are not connected to signal line Sig250~750 of the pixel array 200. However, it is not limited to this, and ROI3 may be composed of pixels that are not located in the illumination region and are connected to a different signal line Sig from the pixels P located in the illumination region among the multiple signal line Sig. For example, the pixels P located in ROI3 may be composed of pixels P located in regions of the pixel array 200 other than the illumination region and the crosstalk generation region.

[0048] After calculating the average value of each signal from ROI1 to ROI3, in S104, the image generation circuit 113 calculates the amount of signal generated by crosstalk on the signal line Sig by subtracting the average value of the signal value of ROI1 from the average value of the signal value of ROI2. Next, in S105, the difference in signal amounts between ROI1 and ROI2 calculated in S104 is divided by the average value of the signal of ROI1 calculated in S103 to calculate a coefficient for crosstalk correction. This allows obtaining the percentage (coefficient) of the amount of crosstalk that is expected to occur in the pixel arrays 200 and 200' when irradiated with radiation. The calculation results in each step from S103 to S105 in this embodiment are shown in Figure 7(c). As shown in Figure 7(c), the coefficient for correcting crosstalk is calculated to be 9.5%.

[0049] The above explanation described obtaining a crosstalk correction coefficient using the average signal value of the signals output from pixels P located in ROI1 to ROI3. However, this is not the only method. For example, the signal value of the signals output from pixels P located in the ROI3 region is likely to be small, as there is virtually no crosstalk caused by radiation exposure. Therefore, without setting ROI3, the crosstalk correction coefficient can be obtained by dividing the average signal value of the signals output from pixels P located in ROI2 by the average signal value of the signals output from pixels P located in ROI1.

[0050] Furthermore, the selection of pixels P located in each of the ROI1 to 3 may be determined, for example, by the user positioning a subject (jig) for determining the crosstalk correction coefficient and inputting radiation irradiation information during the operation to acquire the coefficient into the computer 120. The irradiation information may include information on pixels P located in the irradiation area, information on pixels P located in the crosstalk generation area, and information on pixels P that are not located in the irradiation area and are connected to a different signal line Sig from the pixels P located in the irradiation area among multiple signal line Sig. The computer 120 controls the drive circuit 210 and the readout circuit 220 according to the irradiation information. As a result, the readout circuit 220 can acquire signals from pixels P located in each of the ROI1 to 3 according to the radiation irradiation information during the operation to acquire the crosstalk correction coefficient. It is also conceivable that the positional relationship between the subject (jig) for determining the crosstalk correction coefficient and the radiation detection panel 111 (pixel array 200, 200') remains constant. For example, there may be a dedicated object (jig) used when acquiring crosstalk correction coefficients for the radiation imaging device 110, and a guide for attaching the object (jig) to the radiation detection panel 111 may be provided. In that case, when the button for generating the correction coefficient in the interface attached to the computer 120 is pressed, the computer 120 may automatically control the drive circuit 210 and the readout circuit 220 to acquire signals from the pixels P located in each of the ROIs 1 to 3.

[0051] Next, the process of acquiring radiation images and correcting crosstalk will be described with reference to Figures 8 and 9. First, before radiation irradiation in S201, the user places the subject to be imaged 150 between the radiation detection panel 111 (pixel array 200, 200') and the radiation generator 140. In this embodiment, the subject 150 is a printed circuit board with electronic components mounted on it, as shown in the uncorrected image 900 in Figure 9. Next, the user sets the computer 120 to perform radiation image acquisition via an interface attached to the computer 120. Subsequently, for example, by the user pressing the exposure switch, the computer 120 controls the exposure control device 130, and radiation is continuously irradiated from the radiation generator 140 towards the radiation imaging device 110. The radiation imaging device 110 generates a signal for the radiation image of the subject 150 in the manner described above with reference to Figure 4.

[0052] Next, in S202, the radiation imaging device 110 transmits the signals generated by the radiation detection panel 111 (pixel arrays 200, 200') to the image generation circuit 113, which functions as a processing circuit for processing the signals, via the readout circuit 220. In S203, the image generation circuit 113 averages the signal values ​​of the received signals column by column in both the pixel array 200 and the pixel array 200', and generates a horizontal profile. The horizontal profile 901 of the signal output from the pixel array 200 is the average of the signal values ​​of rows 1 to 500 shown in Figure 2, column by column. The horizontal profile 902 of the signal output from the pixel array 200' is the average of the signal values ​​of rows 501 to 1000 shown in Figure 2, column by column. Next, in S204, the image generation circuit 113 expands the generated horizontal profile with the same values ​​in the column direction to generate a profile image 903. Profile image 903 is created by expanding profile 901 from line 1 to line 500, and profile 902 from line 501 to line 1000.

[0053] After generating the profile image 903, in S205, the image generation circuit 113 multiplies the signal value of each pixel P in the generated profile image 903 by a coefficient that is uniform to all pixels. The coefficient is the crosstalk correction coefficient generated in the correction coefficient generation flow described above. For example, as described above, the coefficient 0.095 is multiplied by the signal value of each pixel P in the profile image 903. Next, in S206, the image generation circuit 113 subtracts the signals of the corresponding rows and columns of the profile image generated in S205 from the signal values ​​of each pixel P received in S202. This generates the pixel values ​​of the crosstalk-corrected image 904.

[0054] In other words, the image generation circuit 113, which functions as a processing circuit for signals read from pixel arrays 200 and 200', can be said to operate as follows for each column corresponding to the signal line Sig of pixel arrays 200 and 200'. For each column, the image generation circuit 113 generates a correction value (profile image 903) by multiplying the average value (profiles 901 and 902) of the signal values ​​of multiple signals read from multiple pixels P arranged in that column by a crosstalk correction coefficient. The crosstalk correction coefficient is common to each column. Next, the image generation circuit 113 generates signal values ​​of multiple signals for a radiographic image by subtracting the correction value from each of the signal values ​​of multiple signals read from multiple pixels P arranged in that column. Here, when generating profiles 901 and 902, the average value of the signal values ​​of the signals read from pixels P was calculated, but the integrated value of the signal values ​​of the signals read from pixels P may also be used as profiles 901 and 902.

[0055] As described above, by multiplying the average value of the signals for each column by a coefficient (percentage) for crosstalk correction, the amount of crosstalk that is expected to be superimposed on the signal line Sig for each column can be determined (S205). Next, by subtracting this expected amount of crosstalk for each column from the signal value of the signal output from each pixel P of the corresponding column, the crosstalk superimposed on each signal line Sig due to radiation irradiation can be corrected (S206). Furthermore, consider the case where the radiation detection panel 111 is composed of a pixel array 200 and a pixel array 200', as in this embodiment. In that case, the amount of crosstalk superimposed on each signal line Sig arranged in the pixel array 200 and each signal line Sig' arranged in the pixel array 200' is likely to be different. For example, the amount of crosstalk between the pixel array 200 and the pixel array 200' may differ significantly depending on the arrangement of the subject. In image 900 shown in Figure 9, the area corresponding to pixel array 200 has a larger area without a subject and a wider area irradiated with more radiation than the area corresponding to pixel array 200'. Therefore, the amount of crosstalk superimposed on the signal line Sig in pixel array 200 may be greater than the amount of crosstalk superimposed on the signal line Sig' in pixel array 200'. As a result, in the uncorrected image 900 shown in Figure 9, there is a step in brightness between the area corresponding to pixel array 200 and the area corresponding to pixel array 200'. On the other hand, as described above, by assuming the amount of crosstalk superimposed for each signal line Sig and performing correction, the step in brightness between the area corresponding to pixel array 200 and the area corresponding to pixel array 200' is less visible in the corrected image 904. In other words, the above processing makes it possible to acquire images with reduced artifacts caused by crosstalk.

[0056] Furthermore, the processing in this embodiment can suppress the effects of crosstalk without repeatedly performing the operation of reading out signals corresponding to the charge accumulated from each pixel P and the operation of reading out the crosstalk component signal by making all the switch elements S non-conductive when obtaining a radiation image. In other words, one radiation image can be generated with a single readout operation. This makes it possible to improve the performance of the radiation imaging device 110, such as by increasing the frame rate and reducing power consumption. In other words, it becomes possible to reduce artifacts caused by crosstalk when imaging moving images at high frame rates. It also becomes possible to perform imaging with reduced artifacts caused by crosstalk while keeping power consumption down.

[0057] The generation of crosstalk correction coefficients, as explained using Figures 6 and 7, may be performed each time before imaging, such as for moving images. Alternatively, the generation of crosstalk correction coefficients may be performed after the start-up of the radiation imaging device 110. Furthermore, for example, the computer 120 may display a screen on the interface instructing the generation of crosstalk correction coefficients according to the elapsed time since the previous generation of crosstalk correction coefficients. Alternatively, for example, the acquisition of crosstalk correction coefficients may be performed during factory inspection before shipment, and the coefficients determined during the factory inspection may be used continuously. The acquisition of crosstalk correction coefficients may be performed by the user as described above, or, for example, by a manufacturer's service technician. The acquisition of crosstalk correction coefficients should be performed at an appropriate timing.

[0058] Furthermore, the above description illustrates an example in which the image generation circuit 113, located in the radiation imaging device 110, functions as a processing circuit for processing signals generated by the radiation detection panel 111 (pixel arrays 200, 200'). However, it is not limited to this. For example, the computer 120 may function as a processing circuit (processing device) for processing signals generated by the radiation detection panel 111 (pixel arrays 200, 200'). Alternatively, for example, a processing device (processing circuit) for processing signals generated by the radiation detection panel 111 (pixel arrays 200, 200') may be located in the radiation imaging system 100, separate from the radiation imaging device 110 and the computer 120.

[0059] Next, a modified example of the above-described radiation imaging device 110 will be explained. In the above-described embodiment, the case in which radiation is continuously irradiated from the radiation generator 140 toward the radiation imaging device 110 when acquiring continuous radiation images such as moving images was explained. However, the method of radiation irradiation is not limited to this. When acquiring continuous radiation images such as moving images, radiation may be irradiated from the radiation generator 140 toward the radiation imaging device 110 in a pulsed manner according to the acquisition of each radiation image.

[0060] When radiation such as X-rays is irradiated in a pulsed manner, the radiation may gradually decay over time after being emitted from the radiation generator 140 under predetermined conditions. As shown in Figure 10, the degree of decay after irradiation varies depending on conditions such as the tube voltage and tube current set in the radiation generator 140. If the period during which the radiation decays is included in the readout period shown in Figure 4, the charge generated in the conversion element C will be less than when the radiation is irradiated continuously, and the amount of crosstalk may be reduced. Furthermore, since the amount of charge generated in the conversion element C may change depending on the degree of radiation attenuation, the amount of crosstalk may change depending on the setting conditions of the radiation generator, such as the tube voltage and tube current. For this reason, crosstalk correction coefficients, such as the setting conditions of the radiation generator 140 for irradiating the radiation imaging device 110 with radiation, may be set to different values ​​depending on the imaging conditions for acquiring the radiation image.

[0061] Referring to Figures 11 and 12, the method for generating crosstalk correction coefficients in this embodiment will be described. Similar to S101 shown in Figure 6 above, first, a subject (jig) for determining the crosstalk correction coefficients is positioned so that radiation is irradiated onto a part of the radiation detection panel 111 (pixel array 200, 200'). The positioning of the subject only needs to be completed by S302. In S301, the computer 120 sets the initial value of 1 as the management number K. Next, in S302, the computer 120 controls the exposure control device 130, and the radiation generator 140 irradiates the radiation imaging device 110 with radiation under the condition K=1 shown in Figure 12. The steps S303 to S306 may be the same as the steps S102 to S105 above, so their explanation is omitted here.

[0062] After obtaining the crosstalk correction coefficient under the condition K=1 shown in Figure 12, the process proceeds to S307. In S307, the computer 120 overwrites the management number K by adding 1. Next, in S308, the computer 120 determines whether the management number K is greater than the upper limit Kmax. If the determination result is No, the process from S302 to S307 is repeated. If the determination result in S308 is Yes, the process of obtaining the crosstalk correction coefficient is completed. Through the above process, a crosstalk correction coefficient can be obtained for each imaging condition for acquiring a radiation image. The crosstalk correction coefficients obtained according to the setting conditions of the radiation generator 140 for irradiating the radiation imaging device 110 with radiation are shown in Figure 12. The radiation imaging device 110 may have a memory that stores multiple imaging conditions and multiple values ​​of the crosstalk correction coefficient in association. Furthermore, for example, multiple imaging conditions and multiple values ​​for crosstalk correction coefficients may be stored in the memory of the computer 120 in association with each other. In addition, a separate memory for storing multiple imaging conditions and multiple values ​​for crosstalk correction coefficients in association with each other may be provided in the radiation imaging system 100, separate from the radiation imaging device 110 and the computer 120.

[0063] Next, with reference to Figure 13, the flow of imaging and crosstalk correction of radiation images will be described. First, before radiation is irradiated in S401, the user places the subject to be imaged 150 between the radiation detection panel 111 (pixel array 200, 200') and the radiation generator 140. The user also inputs imaging conditions for acquiring radiation images via an interface attached to the computer 120. Here, the imaging conditions can be selected from 19 types of setting conditions for the radiation generator 140, as shown in Figure 12. For example, as shown in Figure 12, the setting conditions include conditions in which radiation is continuously irradiated when acquiring radiation images continuously, and conditions in which radiation is irradiated pulsed according to the acquisition of each radiation image. The setting conditions may also include at least one of the tube current, tube voltage, and pulse width set in the radiation generator 140. After selecting the setting conditions, for example, by the user pressing the exposure switch, the computer 120 controls the exposure control device 130, and the radiation generator 140 irradiates radiation toward the radiation imaging device 110. Subsequently, steps S402 to S405 may be the same as steps S201 to S204 explained using Figure 8, so their explanation is omitted here.

[0064] Next, in S406, the image generation circuit 113 selects a crosstalk correction coefficient that corresponds to the imaging conditions entered by the user before radiation irradiation. As described above, the crosstalk correction coefficient is stored in the memory of the radiation imaging device 110, the computer 120, or the radiation imaging system 100. In S407, similar to the process in S205 described above, the image generation circuit 113 multiplies the signal value of each pixel P in the generated profile image 903 by the crosstalk correction coefficient selected in S406, uniformly for all pixels. The subsequent process in S408 may be the same as the process in S206 described above, so its explanation is omitted here. Through the above processing, the radiation imaging device 110 can accurately correct crosstalk that may change depending on the settings of the radiation generator 140.

[0065] Thus, by setting the crosstalk correction coefficient to a different value depending on the imaging conditions for acquiring the radiation image, the accuracy of crosstalk correction is improved. Furthermore, as mentioned above, the setting conditions of the radiation generator 140 for irradiating the radiation imaging device 110 with radiation were given as imaging conditions. However, the imaging conditions are not limited to these. For example, the amount of crosstalk may change depending on the frame rate when acquiring radiation images such as moving images. Therefore, the imaging conditions for acquiring radiation images may also include the frame rate for acquiring the radiation image. In addition to the crosstalk correction coefficient according to the setting conditions of the radiation generator 140 shown in Figure 12, a crosstalk correction coefficient according to the frame rate may be acquired and selected in step S406 shown in Figure 13. Also, for example, the amount of crosstalk may change depending on the ratio of the accumulation period for accumulating charge in the pixels P arranged in the pixel arrays 200 and 200' and the readout period for reading signals from the pixels P arranged in the pixel arrays 200 and 200' when acquiring radiation images. Therefore, the imaging conditions for acquiring a radiographic image may include the ratio of the imaging period to the readout period when acquiring the radiographic image. In addition to the crosstalk correction coefficient according to the setting conditions of the radiation generator 140 shown in Figure 12, a crosstalk correction coefficient according to the ratio of the imaging period to the readout period may be acquired and selected in step S406 shown in Figure 13. Furthermore, a crosstalk correction coefficient may be acquired according to appropriate imaging conditions for acquiring a radiographic image and used when generating the radiographic image.

[0066] (Other examples) The present invention can also be realized by supplying a program that implements one or more of the functions of the above-described embodiments to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. It can also be realized by a circuit (e.g., an ASIC) that implements one or more functions.

[0067] The disclosures herein include the following radiographic imaging devices, radiographic imaging systems, processing devices, processing methods, and programs.

[0068] (Item 1) A radiation imaging apparatus comprising: a pixel array in which multiple pixels are arranged in each column to form multiple columns; and a processing circuit for processing signals read from the pixel array via multiple signal lines, The processing circuit generates a correction value for each column by multiplying the integrated or average value of the signal values ​​of multiple first signals read from multiple pixels arranged in that column by a crosstalk correction coefficient, and then generates multiple second signal values ​​for a radiographic image by subtracting the correction value from each of the signal values ​​of the multiple first signals. A radiation imaging apparatus characterized in that the coefficient is common to each column.

[0069] (Item 2) The radiation imaging apparatus according to item 1, characterized in that the coefficient is set to a different value depending on the imaging conditions for acquiring a radiation image.

[0070] (Item 3) The radiation imaging apparatus according to item 2, characterized in that the imaging conditions include setting conditions for a radiation generator for irradiating the radiation imaging apparatus with radiation.

[0071] (Item 4) The radiation imaging apparatus according to item 3, characterized in that the setting conditions include a case in which radiation is continuously irradiated when acquiring radiation images in succession, and a case in which radiation is irradiated in a pulsed manner according to the imaging of each radiation image.

[0072] (Item 5) The radiation imaging apparatus according to item 3 or 4, characterized in that the setting conditions include at least one of tube current, tube voltage, and pulse width.

[0073] (Item 6) The radiation imaging apparatus according to any one of items 2 to 5, characterized in that the imaging conditions include the ratio of an accumulation period for accumulating charge in pixels arranged in the pixel array and a readout period for reading signals from pixels arranged in the pixel array.

[0074] (Item 7) The radiation imaging apparatus according to any one of items 2 to 6, characterized in that the imaging conditions include the frame rate for acquiring the radiation image.

[0075] (Item 8) A radiation imaging apparatus according to any one of items 2 to 7, further comprising a memory for storing multiple imaging conditions and multiple values ​​of the coefficients in association with each other.

[0076] (Item 9) A radiation imaging apparatus according to any one of items 1 to 8, characterized in that the plurality of columns and the plurality of signal lines are arranged in the pixel array such that one of the plurality of signal lines corresponds to one of the plurality of columns.

[0077] (Item 10) The system further includes a readout circuit that reads signals from the pixel array via the plurality of signal lines, The processing circuit processes the signal read by the reading circuit, In the operation to obtain the coefficient, a portion of the pixel array is irradiated with radiation, The pixels arranged in the pixel array include a plurality of first pixels arranged in the portion, and a plurality of second pixels that are not arranged in the portion and are connected to the same signal line as the pixels arranged in the portion, The readout circuit reads out a plurality of third signals from the plurality of first pixels and a plurality of fourth signals from the plurality of second pixels according to the radiation irradiation information in the operation. The radiation imaging apparatus according to any one of items 1 to 9, characterized in that the processing circuit obtains the coefficient based on the plurality of third signals and the plurality of fourth signals.

[0078] (Item 11) The radiation imaging apparatus according to item 10, characterized in that the processing circuit obtains the coefficient by dividing the average value of the signal values ​​of the plurality of fourth signals by the average value of the signal values ​​of the plurality of third signals and the plurality of fourth signals.

[0079] (Item 12) The system further includes a readout circuit that reads signals from the pixel array via the plurality of signal lines, The processing circuit processes the signal read by the reading circuit, In the operation to obtain the coefficient, a portion of the pixel array is irradiated with radiation, The pixels arranged in the pixel array include a plurality of first pixels arranged in the portion, a plurality of second pixels not arranged in the portion and connected to the same signal line as the pixels arranged in the portion, and a plurality of third pixels not arranged in the portion and connected to a different signal line from the plurality of signal lines than the pixels arranged in the portion. The readout circuit reads out a plurality of third signals from the plurality of first pixels, a plurality of fourth signals from the plurality of second pixels, and a plurality of fifth signals from the plurality of third pixels, according to the radiation irradiation information in the operation. The radiation imaging apparatus according to any one of items 1 to 9, characterized in that the processing circuit obtains the coefficient based on the plurality of third signals, the plurality of fourth signals, and the plurality of fifth signals.

[0080] (Item 13) The radiation imaging apparatus according to item 12, characterized in that the processing circuit obtains the coefficient by dividing the difference between the average value of the signal values ​​of the plurality of fourth signals and the average value of the signal values ​​of the plurality of fifth signals by the average value of the signal values ​​of the plurality of third signals and the fourth signals.

[0081] (Item 14) The aforementioned pixel array is designated as the first pixel array, and further comprises a second pixel array, The radiation imaging apparatus according to any one of items 1 to 13, characterized in that the processing circuit processes signals read from the first pixel array and the second pixel array.

[0082] (Item 15) The aforementioned pixel array is referred to as the first pixel array, and the aforementioned readout circuit as the first readout circuit, further comprising a second pixel array and a second readout circuit. The processing circuit processes the signals read by the first read circuit and the second read circuit. The aforementioned portion is set in the first pixel array, The radiation imaging apparatus according to item 12 or 13, characterized in that the third pixel is arranged in the second pixel array.

[0083] (Item 16) A radiographic imaging device as described in any one of items 1 through 15, A signal processing unit that processes signals output from the aforementioned radiation imaging device, A radiation imaging system characterized by having the following features.

[0084] (Item 17) A processing device that processes signals read out via multiple signal lines from a pixel array in which multiple pixels are arranged in each column to form multiple columns, The processing device generates a correction value for the signal output from each column by multiplying the integrated or average value of the signal values ​​of multiple first signals read from multiple pixels arranged in that column by a crosstalk correction coefficient, and then generates multiple second signal values ​​for a radiographic image by subtracting the correction value from each of the signal values ​​of the multiple first signals. The processing apparatus is characterized in that the coefficient is common to each column.

[0085] (Item 18) A method for processing signals read out via multiple signal lines from a pixel array in which multiple pixels are arranged in each column to form multiple columns, The aforementioned processing method applies to the signals output from each column, A step of generating a correction value by multiplying the integrated or average value of the signal values ​​of multiple first signals read from multiple pixels arranged in the column by a coefficient for crosstalk correction, A step of generating a plurality of second signals for a radiographic image by subtracting the correction value from each of the signal values ​​of the plurality of first signals, Includes, The processing method is characterized in that the coefficient is common to each column.

[0086] (Item 19) The processing method described above is used to obtain the coefficient, The process of arranging the subject so that a portion of the pixel array is irradiated with radiation, The process involves reading out multiple third signals from multiple first pixels arranged in the aforementioned part, A step of reading out a plurality of fourth signals from a plurality of second pixels that are not located in the aforementioned portion and are connected to the same signal line as the pixels located in the aforementioned portion of the plurality of signal lines, A step of generating the coefficient based on the plurality of third signals and the plurality of fourth signals, The processing method according to item 18, characterized by including the following.

[0087] (Item 20) A program that causes a computer to perform each step of the processing method described in item 18 or 19.

[0088] The invention is not limited to the embodiments described above, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, claims are attached to disclose the scope of the invention. [Explanation of Symbols]

[0089] 110: Radiation imaging device, 200,200': Pixel array, P: Pixel, Sig: Signal line

Claims

1. A radiation imaging apparatus comprising: a pixel array in which multiple pixels are arranged in each column to form multiple columns; and a processing circuit for processing signals read from the pixel array via multiple signal lines, The processing circuit generates a correction value for each column by multiplying the integrated or average value of the signal values ​​of multiple first signals read from multiple pixels arranged in that column by a crosstalk correction coefficient, and then generates multiple second signal values ​​for a radiographic image by subtracting the correction value from each of the signal values ​​of the multiple first signals. A radiation imaging apparatus characterized in that the coefficient is common to each column.

2. The radiation imaging apparatus according to claim 1, characterized in that the coefficient is set to a different value depending on the imaging conditions for acquiring a radiation image.

3. The radiation imaging apparatus according to claim 2, characterized in that the imaging conditions include setting conditions for a radiation generator for irradiating the radiation imaging apparatus with radiation.

4. The radiation imaging apparatus according to claim 3, characterized in that the setting conditions include a case in which radiation is continuously irradiated when acquiring radiation images in succession, and a case in which radiation is irradiated in a pulsed manner according to the imaging of each radiation image.

5. The radiation imaging apparatus according to claim 3, characterized in that the setting conditions include at least one of tube current, tube voltage, and pulse width.

6. The radiation imaging apparatus according to claim 2, characterized in that the imaging conditions include the ratio of an accumulation period for accumulating charge in pixels arranged in the pixel array and a readout period for reading signals from pixels arranged in the pixel array.

7. The radiation imaging apparatus according to claim 2, characterized in that the imaging conditions include the frame rate for acquiring the radiation image.

8. The radiation imaging apparatus according to claim 2, further comprising a memory for storing multiple imaging conditions and multiple values ​​of the coefficients in association with each other.

9. The radiation imaging apparatus according to claim 1, characterized in that the plurality of columns and the plurality of signal lines are arranged in the pixel array such that one of the plurality of signal lines corresponds to one of the plurality of columns.

10. The system further includes a readout circuit that reads signals from the pixel array via the plurality of signal lines, The processing circuit processes the signal read by the reading circuit, In the operation to obtain the coefficient, a portion of the pixel array is irradiated with radiation, The pixels arranged in the pixel array include a plurality of first pixels arranged in the portion, and a plurality of second pixels that are not arranged in the portion and are connected to the same signal line as the pixels arranged in the portion, The readout circuit reads out a plurality of third signals from the plurality of first pixels and a plurality of fourth signals from the plurality of second pixels according to the radiation irradiation information in the operation. The radiation imaging apparatus according to claim 1, characterized in that the processing circuit acquires the coefficient based on the plurality of third signals and the plurality of fourth signals.

11. The radiation imaging apparatus according to claim 10, characterized in that the processing circuit obtains the coefficient by dividing the average value of the signal values ​​of the plurality of fourth signals by the average value of the signal values ​​of the plurality of third signals and the plurality of fourth signals.

12. The system further includes a readout circuit that reads signals from the pixel array via the plurality of signal lines, The processing circuit processes the signal read by the reading circuit, In the operation to obtain the coefficient, a portion of the pixel array is irradiated with radiation, The pixels arranged in the pixel array include a plurality of first pixels arranged in the portion, a plurality of second pixels not arranged in the portion and connected to the same signal line as the pixels arranged in the portion among the plurality of signal lines, and a plurality of third pixels not arranged in the portion and connected to a different signal line from the plurality of signal lines than the pixels arranged in the portion. The readout circuit reads out a plurality of third signals from the plurality of first pixels, a plurality of fourth signals from the plurality of second pixels, and a plurality of fifth signals from the plurality of third pixels, according to the radiation irradiation information in the operation. The radiation imaging apparatus according to claim 1, characterized in that the processing circuit obtains the coefficient based on the plurality of third signals, the plurality of fourth signals, and the plurality of fifth signals.

13. The radiation imaging apparatus according to claim 12, characterized in that the processing circuit obtains the coefficient by dividing the difference between the average value of the signal values ​​of the plurality of fourth signals and the average value of the signal values ​​of the plurality of fifth signals by the average value of the signal values ​​of the plurality of third signals and the fourth signals.

14. The aforementioned pixel array is designated as the first pixel array, and further comprises a second pixel array, The radiation imaging apparatus according to claim 1, characterized in that the processing circuit processes signals read from the first pixel array and the second pixel array.

15. The aforementioned pixel array is referred to as the first pixel array, and the aforementioned readout circuit as the first readout circuit, further comprising a second pixel array and a second readout circuit. The processing circuit processes the signals read by the first read circuit and the second read circuit. The aforementioned portion is set in the first pixel array, The radiation imaging apparatus according to claim 12, characterized in that the third pixel is arranged in the second pixel array.

16. A radiation imaging apparatus according to any one of claims 1 to 15, A signal processing unit that processes signals output from the aforementioned radiation imaging device, A radiation imaging system characterized by having the following features.

17. A processing device that processes signals read out via multiple signal lines from a pixel array in which multiple pixels are arranged in each column to form multiple columns, The processing device generates a correction value for the signal output from each column by multiplying the integrated or average value of the signal values ​​of multiple first signals read from multiple pixels arranged in that column by a crosstalk correction coefficient, and then generates multiple second signal values ​​for a radiographic image by subtracting the correction value from each of the signal values ​​of the multiple first signals. The processing apparatus is characterized in that the coefficient is common to each column.

18. A method for processing signals read out via multiple signal lines from a pixel array in which multiple pixels are arranged in each column to form multiple columns, The aforementioned processing method applies to the signals output from each column, A step of generating a correction value by multiplying the integrated or average value of the signal values ​​of multiple first signals read from multiple pixels arranged in the column by a coefficient for crosstalk correction, A step of generating a plurality of second signals for a radiographic image by subtracting the correction value from each of the signal values ​​of the plurality of first signals, Includes, The processing method is characterized in that the coefficient is common to each column.

19. The processing method described above is used to obtain the coefficient, The process of arranging the subject so that a portion of the pixel array is irradiated with radiation, The process involves reading out multiple third signals from multiple first pixels arranged in the aforementioned part, A step of reading out a plurality of fourth signals from a plurality of second pixels that are not located in the aforementioned portion and are connected to the same signal line as the pixels located in the aforementioned portion of the plurality of signal lines, A step of generating the coefficient based on the plurality of third signals and the plurality of fourth signals, The processing method according to claim 18, characterized by including the following:

20. A program for causing a computer to perform each step of the processing method described in claim 18 or 19.

Images