JP2021040196A - Radiation imaging apparatus, radiation imaging system, and control method of radiation imaging apparatus - Google Patents

Abstract

To provide a technology that can suppress the degradation of sharpness in a radiation imaging apparatus that can be used by switching feedback capacitance of an integrating amplifier.SOLUTION: The imaging apparatus includes a pixel array in which pixels PIX are arranged, a readout circuit 103, and a control unit. The readout circuit includes a holding circuit 324 that holds a plurality of signals read out via an integrating amplifier 302 that includes a feedback capacitance 312 that can change a plurality of capacitance values. The control unit controls the readout circuit so that a time for sampling the signals read out from the pixels PIX in the holding circuit 324 is longer in a first mode than in a second mode when changing from the second mode to the first mode in which the capacitance value of the feedback capacitance 312 is smaller than that of the second mode.SELECTED DRAWING: Figure 3

Description

The present invention relates to a radiation imaging device, a radiation imaging system, and a control method for the radiation imaging device.

Patent Document 1 proposes a radiation imaging device that generates an image signal related to a subject by being irradiated with radiation such as X-rays transmitted through the subject. This radiation imaging device includes a pixel array in which a plurality of pixels including a conversion element that converts radiation into electric charges are arranged in a two-dimensional matrix. The charges generated by the plurality of pixels are transferred to an integrator amplifier provided for each column of the pixel array and integrated. This integral amplifier has a configuration in which the gain (amplification factor) can be changed by switching the capacitance value of the feedback capacitance. This radiation imaging device uses a sample hold circuit to sample and hold the output signal of the integrating amplifier. The radiation imaging apparatus can also perform correlated double sampling (CDS) on the output signal of the integrating amplifier using two sample hold circuits in order to remove low frequency noise from the output signal of the integrating amplifier. Then, in this radiation imaging device, the output signal held in the sample hold circuit is subjected to parallel series conversion processing (multiplex processing) and analog-to-digital conversion processing (A / D conversion processing) to obtain image data for one frame. Can be obtained.

Japanese Unexamined Patent Publication No. 2015-198263

When switching the feedback capacitance of the integrator amplifier, when switching to the second capacitance value Cf2 whose feedback capacitance is smaller than the first capacitance value Cf1 mainly used, the charge-voltage conversion in the integrator amplifier is compared with the case of the first capacitance value Cf1. Requires a larger current.

Therefore, in the case of the second capacitance value Cf2, a longer time is required for sampling in the sample hold circuit than in the case of the first capacitance value Cf1. Due to the rate-determining of the charge / discharge capacity and the rate-determining of the sampling time, the output signal cannot be sampled to the sample hold circuit, and as a result, the output signal immediately before being read by the same sample hold circuit is superimposed on the next output signal. The problem of being discharged can occur. By superimposing the output signal, the MTF (Modulation Transfer Function), which is an index of the sharpness of the image, can be lowered. In particular, when performing an operation of transferring a charge-based signal from a pixel in a row to be scanned next to an integral amplifier while performing a parallel-series conversion process of an output signal based on the charge from a pixel in a row, one row is performed. The time allotted around is shortened. In such cases, the above problems may occur more prominently.

Therefore, an object of the present invention is to provide a technique capable of suppressing a decrease in sharpness in a radiation imaging apparatus in which the feedback capacitance of an integrating amplifier can be switched and used.

The radiation imaging apparatus of the present invention samples a plurality of signals read from the plurality of pixels via a pixel array in which a plurality of pixels are arranged and an integrating amplifier including a feedback capacitance capable of changing a plurality of capacitance values. A radiation imaging device including a reading circuit including a holding circuit for holding the reading circuit and a control unit for controlling the reading circuit. The control unit has a capacitance value of the feedback capacitance smaller than that of the second mode. When changing from the second mode to the first mode, the time for sampling the signal read from the pixel in the holding circuit is set so that the first mode is longer than the second mode. It is characterized in that the read circuit is controlled.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a technique capable of suppressing a decrease in sharpness in a radiation imaging apparatus that can be used by switching the feedback capacitance of an integrating amplifier.

Block diagram showing a configuration example of a radiation imaging device and a radiation imaging system Schematic equivalent circuit diagram showing a configuration example of a radiation imaging device Schematic equivalent circuit diagram showing a configuration example of a radiation imaging device Timing chart showing an operation example of a radiation imaging device Timing chart showing an example of operation control for one line period Timing chart showing an example of operation control for one line period Flowchart explaining the process of determining control conditions in control An example of a look-up table that determines control conditions

Hereinafter, an exemplary embodiment of the present invention will be described with reference to the accompanying drawings. However, the details of the structure shown in each embodiment are not limited to those shown in the text and the drawings. In addition to X-rays, radiation also includes α-rays, β-rays, γ-rays, and various particle beams.

FIG. 1 shows the configuration of a radiological imaging system RIS (Radiology Information System) according to an embodiment of the present invention. The radiation imaging system RIS obtains a radiographic image of a subject by irradiating the subject with radiation such as X-rays and detecting X-rays that have passed through the subject. The radiation imaging system RIS may include, for example, a radiation source 112, an exposure control device 113, a control device 111, and a radiation imaging device 100. The exposure control device 113 generates radiation to the radiation source 112 in response to an exposure command by the operator. The control device 111 functions as an image processing device that controls the radiation imaging device 100 and processes an image that acquires a radiation image from the radiation imaging device 100 and displays it on a display device (not shown). Further, the control device 111 controls the exposure control device 113.

The radiation imaging device 100 includes an imaging unit 104 that captures a radiation image, a communication unit 107 that communicates with a control device 111, a control unit 106 that controls the imaging unit 104, and a power supply unit 108 that supplies power to the imaging unit 104. sell. Further, the radiation imaging apparatus 100 may include a determination unit 109 that analyzes and determines an image output from the imaging unit 104, and a processing unit 105 that performs arithmetic processing of the image. Some of the components of the radiation imaging device 100 may be incorporated in the control device 111, or the radiation imaging device 100 and the control device 111 may be integrated. For example, in the example shown in FIG. 1, the determination unit 109 and the processing unit 105 are incorporated in the radiation imaging device 100, but the determination unit 109 and the processing unit 105 may be incorporated in the control device 111.

The imaging unit 104 may include, for example, a pixel array 101, a scanning circuit 102, and a reading circuit 103. The pixel array 101 is configured by arranging a plurality of pixels so as to form a plurality of rows and a plurality of columns. The scanning circuit 102 scans a plurality of rows of the pixel array 101 according to a mode selected from the plurality of modes (shooting modes). The read circuit 103 reads a signal from the pixel array 101. More specifically, the reading circuit 103 reads the signal of the pixel of the row selected by the scanning circuit 102 among the plurality of rows of the pixel array 101. Reading a signal from the pixel array 101 means processing the signal output from the pixel array 101 and outputting the signal corresponding to the signal.

FIGS. 2 and 3 illustrate the equivalent circuit of the imaging unit 104. The pixel PIX may include, for example, a conversion element 201 that converts radiation or light into an electric charge, and a switch element 202 that outputs an electric signal corresponding to the electric charge. In one example, the conversion element 201 is a photoelectric conversion element that converts the light irradiated to the conversion element 201 into electric charges, and is a PIN-type photodiode or a PIN-type photodiode whose main material is amorphous silicon and is arranged on an insulating substrate such as a glass substrate. It is a MIS type photodiode. Further, as the conversion element 201, an indirect type conversion element provided with a wavelength converter that converts radiation into light in a wavelength band that can be detected by the photoelectric conversion element, and a direct type conversion element that directly converts radiation into electric charge are used. Can be adopted.

As the switch element 202, a transistor having a control terminal and two main terminals, for example, a thin film transistor (TFT) can be adopted. One electrode of the conversion element 201 is electrically connected to one of the two main terminals of the switch element 202, and the other electrode is electrically connected to the power supply unit 108 via a common bias line Vs. In FIG. 2, in order to distinguish the conversion elements 201 from each other, the conversion elements 201 are designated by Sij (i indicates a row number and j indicates a column number). Further, in order to distinguish the switch elements 202 from each other, the switch elements 202 are designated by Tij (i indicates a row number and j indicates a column number).

The control terminals of the switch elements 202 of the plurality of pixels PIX constituting one row are connected to the drive line Gi (i is the row number) of the row. For example, the control terminals of the switch elements T11 to T1n of the plurality of pixels PIX constituting the first row are electrically connected to the drive line G1 of the first row. Therefore, the minimum unit for driving the plurality of pixel PIXs of the pixel array 101 by the scanning circuit 102 is the pixel PIXs constituting one row.

The other main terminal of the switch element 202 of the plurality of pixels PIX constituting one row is connected to the signal line Sigma (j is the row number) of the row. For example, the main terminals of the switch elements T11 to Tm1 of the plurality of pixels PIX constituting the first row are electrically connected to the signal line Sigma1 in the first row. While the switch element 202 is in the conductive state, an electric signal corresponding to the electric charge of the conversion element 201 is output to the read circuit 103 via the signal line Sigma. The plurality of signal lines Sign1 to Sign are electrically connected to the read circuit 103.

The read circuit 103 includes a plurality of amplifier circuits 300 for amplifying a plurality of electric signals output in parallel from the pixel array 101 via the plurality of signal lines Sign1 to Sign. Each amplifier circuit 300 may include, for example, an integrator amplifier 302, a sample hold circuit 303, and a buffer amplifier 304 or 305. The integrator amplifier 302 amplifies the electric signal output via the signal line Sigma. The sample hold circuit 303 samples and holds an electric signal from the integrator amplifier 302. The buffer amplifier 304 and the buffer amplifier 305 buffer the electric signal from the sample hold circuit 303.

The integrating amplifier 302 may include, for example, an operational amplifier 311, a feedback capacitance 312, and a reset switch 313. The operational amplifier 311 has an inverting input terminal that receives an electric signal provided via the signal line Sigma, a non-inverting input terminal that receives a reference voltage Vref from a reference power supply, and an output terminal. The feedback capacitance 312 and the reset switch 313 are arranged in parallel between the inverting input terminal and the output terminal. The feedback capacitance 312 may have a variable capacitance value Cf. The sample hold circuit 303 includes a first CDS circuit 341 and a second CDS circuit 342 that perform correlated double sampling (CDS). The first CDS circuit 341 includes a first holding circuit 323 and a second holding circuit 324, and performs correlated double sampling based on an electric signal provided via the signal line Sigj. The buffer amplifier 304 is composed of a differential amplifier, and differentially amplifies and outputs the output from the first holding circuit 323 and the output from the second holding circuit 324. The second CDS circuit 342 includes a first holding circuit 333 and a second holding circuit 334, and performs correlated double sampling based on an electric signal provided via the signal line Sigma. The buffer amplifier 305 is composed of a differential amplifier, and differentially amplifies and outputs the output from the first holding circuit 333 and the output from the second holding circuit 334.

The first holding circuit 323 may include a resistance element 322, a switch 325 and a capacitor 326. The first holding circuit 323 holds the electric signal from the integrating incremental amplifier 302 after being subjected to a low-pass filter process by the resistance element 322 and the capacitor 326. Further, the resistance element 322 can be selectively enabled or disabled by the switch 321.

The second holding circuit 324 may include a resistance element 322, a switch 327 and a capacitor 326. The second holding circuit 323 holds the electric signal from the integrating incremental amplifier 302 after being subjected to a low-pass filter process by the resistance element 322 and the capacitor 328. Further, the resistance element 322 can be selectively enabled or disabled by the switch 321.

The read circuit 103 may further include a multiplexer 306, a buffer amplifier 307, and an A / D converter 308. The multiplexer 306 sequentially selects and outputs electrical signals output in parallel from a plurality of amplifier circuits 300, and outputs them as image signals. The buffer amplifier 307 impedance-converts the image signal output from the multiplexer 306 and outputs an analog electric signal as the image signal Vout. The A / D converter 308 converts the image signal Vout output from the buffer amplifier 307 into digital image data and provides it to the processing unit 105 and the analysis unit 109.

The above-mentioned image signal detection is performed for each read circuit connected to Sign, and one line of image signal is detected. By scanning and repeating this operation up to Gm, the digital image signal on the entire surface of the radiation imaging device is finally detected.

Next, the operation of the image pickup apparatus will be described with reference to FIG. 4 (a) and 4 (b) are timing charts for explaining the imaging operation of the imaging apparatus. In the present embodiment, the radiation imaging apparatus 100 performs a pixel output operation on a line-by-line basis. Here, the one-frame period includes a storage period and a read period. The storage period is a period during which a plurality of pixel PIXs perform a storage operation in which signals corresponding to the irradiated radiation are stored. The read period is a period during which the scan circuit 102 scans a plurality of rows and the read circuit 103 reads a signal for one frame from the pixel array 101.

The radiation imaging device 100 repeatedly performs a pixel reset operation until the exposure switch is pressed and radiation (X-rays) is emitted. The pixel reset operation is an operation of resetting the pixels on the entire surface of the radiation imaging apparatus by repeating scanning line by line by the scanning circuit 102 in the same manner as the reading operation performed during the reading period.

When the exposure switch is pressed and radiation (X-rays) is emitted, the pixel array 101 is irradiated with radiation or light, and each conversion element S11 to S1n is generated with an electric charge corresponding to the irradiated radiation or light. Will be done. Next, the radiation imaging apparatus 100 starts the reset operation shown below. The feedback capacitance 312 is reset by the reset switch 313 to which the control signal RST is given from the control unit 106, and the integrating amplifier 302 which is the transmission path is reset. Then, when the reset switch 313 becomes non-conducting, the reset operation ends. Here, the reset operation is an operation of maintaining the continuity state of the reset switch, and is an operation of returning the potential of the transmission path to a specified initial value.

Next, the radiation imaging apparatus 100 starts the noise component sample hold operation shown below. The control signal ODDCDS1 is given from the control unit 106 to the sample hold circuit unit 303. As a result, the switch 325 of the first holding circuit 323 of the first CDS circuit 341 is conducted, and the noise component of the integrated amplifier 302 is transferred from the reset integrator amplifier 302 to the capacitor 326. The switch 325 is made non-conducting and the noise component is held in the capacitor 326. Then, when the switch 325 becomes non-conducting, the noise component sample hold operation ends. Here, the noise component sample hold operation is an operation of maintaining the conduction state of the switch 325 or the switch 335.

Next, the radiation imaging apparatus 100 starts the output operation of the first line shown below. Here, the start of the output operation of the first line is defined by the rising edge of the drive signal given to the drive wiring G1 of the first line from the scanning circuit 102, and the switch elements T11 to T1n of the pixel PIX of the first line are conducted. To. As a result, analog electric signals (pixel signals) based on the electric charges generated by the conversion elements S11 to S1n on the first line are output from each pixel to the first read circuit 103 in parallel via the signal wirings Sign1 to Sign. To. Then, due to the falling edge of the drive wiring G1, the switch elements T11 to T1n of the pixel PIX in the first row are brought into a non-conducting state, and the output operation from the pixel is completed. In the present invention, the output operation refers to an operation of maintaining the conduction state of the switch element 202 of the pixel PIX. In the following, the pixel signal of the pixel in the mth row and the nth column is referred to as S (m, n).

Next, the radiation imaging device 100 starts the signal sample hold operation shown below. The control signal ODDCDS2 is given from the control unit 106 to the sample hold circuit unit 303, and the switch 327 of the second hold circuit 324 of the first CDS circuit 341 is conducted. The pixel signal of the pixel PIX of the first row read by this is transferred to the capacitor 328 via the integrator amplifier 302. At this time, the noise component of the integrating amplifier 302 is added to the pixel signal. Then, the switch 327 is made non-conducting and the pixel signal to which the noise component is added is held in the capacitor 328. Then, when the switch 327 becomes non-conducting, the signal sample hold operation ends. Here, the signal sample hold operation is an operation of maintaining the conduction state of the switch 327 or the switch 337.

Next, the radiation imaging apparatus 100 starts the signal processing operation shown below. The noise component held in the capacitor 326 and the pixel signal of the pixel in the first row to which the noise component held in the capacitor 328 is added are input to the buffer amplifier 304, which is a differential amplifier, respectively. Then, a signal from which the noise component of each integrating amplifier 302 is removed is output. Then, the signal from which the noise component selectively transferred by the multiplexer 306 is removed is output to the A / D converter 308 via the buffer amplifier 307. The A / D converter 308 converts the output pixel signal into digital data S (1, 1) and outputs it to the processing unit 105 that processes the digital data. The output operation of the second row is performed in parallel with the output operation of the first row, and after the A / D conversion of the first row is performed, it is selectively transferred by the multiplexer 306, as in the first row. Digital data S (1, 2) is output from the A / D converter 308 to the processing unit 105. After that, similarly, the pixel data output operation for the third column to the nth column is sequentially performed. As a result, the digital data S (1, 3) to S (1, n) are output to the processing unit 105, respectively, and the signal processing operation ends. Here, this signal processing operation is performed between the start of the reset operation of a certain line and the start of the reset operation of the line next to the line. That is, the signal processing operation for the pixels of a certain row is performed in parallel with the output operation of the pixels of the row that is operated next to the row in time.

Similarly to the first line, the reset operation, the noise component sample hold operation, the output operation, the signal sample hold operation, and the signal processing operation of the second line are performed. The same processing is sequentially repeated row by row in the third and subsequent rows, and pixel signals corresponding to all the pixels of the pixel array 101 are output.

From the above, the noise component obtained by the first holding circuit 323 of the first CDS circuit 341 and the signal component including the noise component obtained by the second holding circuit 324 of the first CDS circuit 341. The difference becomes an image signal obtained by the read circuit 103. Further, the difference between the noise component obtained by the first holding circuit 333 of the second CDS circuit 342 and the signal component including the noise component obtained by the second holding circuit 334 of the second CDS circuit 342. Is the image signal obtained by the read circuit 103. In addition, each holding circuit also operates as a low-pass filter by the resistance element 322 and each capacitor. Therefore, the voltage of the electric signal held in the capacitor of each CDS circuit shows a transient response. Therefore, the time (sampling time) for the noise component sample hold operation and the signal sample hold operation can be set so that the output from the integrating amplifier 302 is sufficient in consideration of the transient response of the low-pass filter.

However, depending on the capacitance value of the feedback capacitance 312, the sampling time becomes insufficient, the transfer of the signal to be held in each first holding circuit becomes insufficient, and the MTF, which is an index of image sharpness in the column direction, becomes insufficient. I found that it would decrease. This is because when the capacitance value of the feedback capacitance 312 becomes small, a large current is required for the fluctuation of the output voltage of the integrator amplifier 302, but the current that can be passed through the path when sampling each holding circuit is constant. Therefore, it is considered that the cause may be that the capacity required to fluctuate the voltage of each capacitor may be insufficient. This means that, for example, when a radiation image is acquired in an operation mode having different frame rates with feedback capacities 312 capable of switching to a plurality of different capacitance values, the sampling time is set to a large operation mode with a feedback capacitance 312. It can happen when it is set together. If the capacitance value of the feedback capacitance 312 is increased in response to this insufficient capacity, noise increases, which is disadvantageous in terms of the signal-to-noise ratio (SNR). Further, if the sampling time is increased, the time required for one line (one line time) increases, which is disadvantageous from the viewpoint of the frame rate. Therefore, it is required to provide a technique capable of securing MTF and SNR even if the frame rate having a trade-off relationship is set to a predetermined value even in a shooting mode in which the capacity value of the feedback capacity 312 is small. ..

Therefore, as a result of diligent studies, the inventor of the present application has found a solution by controlling the imaging unit 104 of the control unit 106 according to the control of the scanning circuit 102 and the reading circuit 103 of the control unit 106 as follows. The outline of the present invention will be described with reference to FIG. FIG. 5 is a timing chart of a period (one line period) related to a reset operation, a noise component sample hold operation, an output operation, and a signal sample hold operation per line of the timing chart shown in FIG. 4 (b). In FIG. 5, for the sake of simplification of the description, the timing chart for the first CDS circuit 341 will be used, but the second CDS circuit 342 can also be applied. The feedback capacitance 312 has a changeable capacitance value Cf, and in the description using FIG. 5, the case where the first mode captures a radiation image in an imaging mode in which the capacitance value Cf is smaller than that of the second mode is exemplified. doing. The timing at which the switch 327 of the second holding circuit 324 is turned on is variable, and the first mode is advanced as compared with the second mode. As a result, the sampling time of the signal sample holding operation by the second holding circuit 324 is secured according to the capacitance value of the feedback capacitance 312 of the integrating amplifier 311. As a result, when the capacitance value Cf is smaller in the first mode than in the second mode, the sampling time of the signal sample hold operation in the first mode is longer than the sampling time of the signal sample hold operation in the second mode. The first control can be performed.

However, in the change illustrated in FIG. 5, the change time is limited depending on the one-line period, and the desired MTF may not be secured by the change within the one-line period. Specifically, the end of the signal sample hold operation by the control signal ODDCDS2 needs to be set at the maximum until the start timing of the reset operation.

Therefore, as shown in FIG. 6, by making a change to lengthen the one-line period, it is possible to lengthen the sampling time of the second holding circuit 324 by that amount. Specifically, when the frame rate of image acquisition is sufficiently satisfied, the second control for making a change to lengthen the one-line period can be performed, and the sampling time of the second holding circuit 324 is set by the change. It can be lengthened.

Next, using FIG. 7, a flowchart of the determination process by the determination unit 109 in which the control unit 106 determines the control conditions in the imaging mode in which the sampling time of the image signal CDS2 is variable according to the capacitance value Cf of the feedback capacitance 312 is shown. Shown. Here, consider the case where the MTF decrease occurs in the first mode. In step S701, the capacitance value Cf of the first mode is increased to determine whether the SNR is within the permissible range. If it is within the permissible range, the process proceeds to step S702, and if it is not within the permissible range, the process proceeds to step S711. In step S702, it is determined whether or not the capacitance value Cf of the first mode is increased to satisfy a predetermined MTF. If the predetermined MTF is satisfied, the imaging mode is determined under the control conditions, and if not satisfied, the process proceeds to step S711. In step S711, the control condition for lengthening the sampling time of the signal sample hold operation is changed in one line period. Next, in step S712, it is determined whether or not the sampling time of the signal sample hold operation is lengthened in one line period to satisfy a predetermined MTF. If the predetermined MTF is satisfied, the imaging mode is determined under the control conditions, and if not satisfied, the process proceeds to step S721. In step S721, it is determined whether or not the control condition sufficiently satisfies the frame rate. If it is satisfied, the process proceeds to step S722, and if it is not satisfied, it is determined that imaging is not possible. In step S722, the control conditions are changed so that the one-line period is lengthened and the sampling time of the second holding circuit 324 is lengthened accordingly. Next, in step S723, it is determined whether or not the control condition is changed to satisfy a predetermined MTF. If the predetermined MTF is satisfied, the imaging mode is determined under the control conditions, and if it is not satisfied, it is determined that imaging is not possible.

The flow is the same even when the frame rate of the first mode is smaller than that of the second mode, and the first mode is changed to lengthen the sampling time of the signal sample hold operation as compared with the second mode. be able to. The process of securing a predetermined MTF is the same as that of the flow as shown in FIG. It should be noted that the determination as to whether or not the predetermined MTF is satisfied can be determined by the amount of deterioration in the sub-scanning direction with respect to the main scanning direction of the MTF. When it is determined to change, the time to be changed can be determined by the amount of deterioration in the sub-scanning direction with respect to the main scanning direction of the MTF. It is also possible to obtain a predetermined MTF by increasing the capacitance value Cf of the feedback capacitance 312 and reducing the required charging time without changing the sampling time of the signal sample hold operation.

However, it is known that increasing the capacitance value Cf of the feedback capacitance 312 worsens the SNR of the image. Therefore, in consideration of the trade-off between MTF and SNR, it is necessary to set the capacitance value Cf of the feedback capacitance 312. Therefore, it is preferable to determine the sampling time CDS of the signal sample hold operation by using a look-up table in which the capacitance value Cf and the frame rate FPS are used as a matrix as shown in FIG. For example, in the imaging mode in which the capacitance value is Cf (C) and the frame rate is FPS (a), the sampling time CDS of the signal sample hold operation can be set to CDS2 (Ca) in advance. By using such a look-up table, it is possible to prepare in advance an imaging mode in which an appropriate sampling time CDS2 is set according to the capacitance value Cf and the frame rate FPS. Thereby, the imaging mode capable of realizing a predetermined MTF can be easily selected according to the required capacitance value Cf and the frame rate FPS.

The invention is not limited to the above embodiment, and various modifications and modifications can be made without departing from the spirit and scope of the invention. Therefore, a claim is attached to make the scope of the invention public.

100 Radiation Imaging Device 101 Pixel Array 103 Read Circuit 106 Control Unit 302 Integral Amplifier 312 Feedback Capacity 324 Second Holding Circuit

Claims (10)

A pixel array in which multiple pixels are arranged and
A read circuit including a hold circuit that samples and holds a plurality of signals read from the plurality of pixels via an integrator amplifier that includes a feedback capacitance that can change a plurality of capacitance values.
A control unit that controls the read circuit and
It is a radiation imaging device including
When the control unit changes from the second mode to the first mode in which the capacitance value of the feedback capacitance is smaller than that of the second mode, the holding circuit is given a time to sample the signal read from the pixel. , The radiation imaging apparatus, characterized in that the reading circuit is controlled so that the first mode is longer than the second mode. In the pixel array, the plurality of pixels are arranged so as to form a plurality of rows and a plurality of columns.
The integrating amplifier includes a reset switch that resets the feedback capacitance.
The control unit includes a reset operation in which the reset switch resets the feedback capacitance, an output operation in which a signal is output from a pixel in at least one of the plurality of rows to the read circuit after the reset operation, and the output operation. A signal sample hold operation that samples and holds the signal output by the output operation, and a one-line period that is a period from the reset operation per line to the signal sample hold operation in units of the plurality of lines. The radiation imaging apparatus according to claim 1, wherein the radiation imaging apparatus is repeatedly performed. The radiation imaging apparatus according to claim 2, wherein the control unit performs first control for lengthening the sampling time within the one-line period. The radiation imaging apparatus according to claim 3, wherein the control unit performs a second control for changing the one-line period so that the first mode is longer than the second mode. The radiation imaging apparatus according to claim 4, wherein the control unit makes a change to lengthen the one-line period in the second control, and the sampling time is lengthened by the change. The radiation imaging apparatus according to claim 5, wherein the control unit determines control conditions so as to perform at least one of the first control and the second control. The radiation imaging apparatus according to claim 6, wherein the control unit determines the control conditions in consideration of SNR, which is a signal-to-noise ratio, and MTF, which is an index of image sharpness. The radiation imaging apparatus according to claim 7, further comprising a determination unit for determining whether or not the MTF satisfies a predetermined MTF when determining the control conditions. The radiation imaging apparatus according to any one of claims 1 to 8.
An image processing device that processes a radiation image acquired from the radiation imaging device and displayed on the display device, and an image processing device.
Radiation imaging system including. Includes a pixel array in which a plurality of pixels are arranged, and a holding circuit that samples and holds a plurality of signals read from the plurality of pixels via an integrating amplifier including a feedback capacitance capable of changing a plurality of capacitance values. A method of controlling a radiation imaging device including a read circuit.
When changing from the second mode to the first mode in which the capacitance value of the feedback capacitance is smaller than the second mode, the time for sampling the signal read from the pixel in the holding circuit is set to the second mode. A control method comprising controlling the read circuit so that the first mode is longer than the mode.

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