JP2014029305A - Radiation imaging apparatus, control method for radiation imaging apparatus, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable all radiographic images to be output while attaining radiation imaging at a high frame rate.SOLUTION: There is provided a radiation imaging apparatus which includes: a synchronization signal detection part for detecting a synchronization signal; an imaging request signal detection part for detecting an imaging request signal showing that it is in a series of imaging periods at imaging intervals corresponding to the synchronization signal; an accumulation part for converting radiation ray radiated at an imaging interval to an electronic signal and accumulates it; and an output part for sample-holding an electric signal and outputting as an analog signal for each pixel circuit. When a frame rate based on an imaging interval exceeds a reference value, the output part outputs a prescribed number of pixels among pixel circuits, thereafter temporarily stops outputting, and when after the temporary stoppage of outputting, an imaging request signal is not detected, it resumes output as to remaining pixel circuits.

Description

  The present invention relates to a radiation imaging apparatus, a method for controlling the radiation imaging apparatus, and a program, and more particularly to a radiation imaging apparatus and a radiation imaging apparatus that realize a high frame rate when imaging is performed by intermittently irradiating a subject with radiation. Control method and program.

  In recent years, in the field of radiation imaging devices, especially digital X-ray imaging devices, instead of an image intensifier, the same magnification using a photoelectric conversion element is used for the purpose of improving resolution, reducing the volume, and suppressing image distortion. 2. Description of the Related Art Large-area flat panel type radiation imaging apparatuses for optical systems have become widespread.

  A large-area flat panel sensor constructed by two-dimensionally connecting photoelectric conversion elements generated by a CMOS semiconductor manufacturing process on a silicon semiconductor wafer as one of flat panel sensors of an equal magnification optical system used in a radiation imaging apparatus There is.

  In Patent Document 1, in order to realize a large area flat panel sensor larger than a silicon semiconductor wafer size, a plurality of rectangular semiconductor substrates, which are rectangular imaging elements obtained by cutting out photoelectric conversion elements from a silicon semiconductor wafer into strips, are tiled. A manufacturing method for a large area flat panel sensor is disclosed.

  Patent Document 2 discloses a circuit configuration of a rectangular semiconductor substrate obtained by cutting a photoelectric conversion element into a strip shape. On a rectangular semiconductor substrate cut out in a strip shape, a vertical shift register and a horizontal shift register are configured as a read control circuit together with two-dimensionally aligned photoelectric conversion elements. An external terminal (electrode pad) is provided in the vicinity of the horizontal shift register. A vertical shift register and a horizontal shift register on a rectangular semiconductor substrate are controlled by a control signal and a clock signal input from an external terminal, and each pixel column is sequentially output from each shift register in synchronization with the clock signal.

  In Patent Document 3, a sampled and held voltage is read as an analog signal by scanning each rectangular semiconductor substrate with a horizontal and vertical shift register, and the analog signal is converted into a digital signal by an A / D converter. Thus, a radiation imaging apparatus that generates a digital image signal is disclosed. By performing scanning when radiation exposure is performed, radiation accumulation and shift register scanning can be performed at the same timing, which makes it possible to support moving image shooting at a high frame rate.

  Patent Document 4 discloses a radiation imaging apparatus that suppresses artifacts in a moving image by stopping analog signal scanning during a reset operation for starting the accumulation of radiation signals.

JP 2002-026302 A Japanese Patent No. 4724313 Japanese Patent No. 4809999 JP2012-085124A

  However, in the radiation imaging apparatus described in Patent Document 4, the drive control is performed so as to temporarily stop the output of the analog signal of the semiconductor circuit board in order to avoid the influence due to the fluctuation of the power supply voltage of the semiconductor circuit board accompanying the reset driving. In this case, after the output of the analog signal is temporarily stopped for the last frame, the output of the remaining analog signals cannot be resumed, and the image of the last frame is discarded.

  That is, as shown in FIG. 7, when the synchronization signal SYNC is detected at time t1, a reset operation for resetting the sensor by applying a reset voltage to a floating diffusion capacitor (not shown) to acquire an image of the frame. Starts from time t2. Then, at time t4, the reset operation ends, and radiation exposure A becomes effective. After the radiation exposure A is completed during the accumulation time XT, the reset operation is performed from time t6 to time t8, and the analog output scanning A1 (scanning time ST1) is started from time t8. When an analog signal having a predetermined number of pixels is output, scanning of the shift register is stopped at time t9 to stop analog output. After a predetermined time has elapsed since the next synchronization signal SYNC was detected at time t10, analog output scanning A2 (scanning time ST2) is executed during the period from time t13 to time t14, and the remaining pixels are output.

  On the other hand, when the synchronization signal SYNC detected at time t10 is a signal for photographing the last frame, the synchronization signal SYNC is not input thereafter. When the synchronization signal SYNC of the last frame is detected at time t10, a reset operation starts from time t11 in order to acquire the image of the last frame. At time t12, the reset operation ends and radiation exposure B becomes effective.

  Then, the analog output scanning B1 of the final frame is started from time t15, and when an analog signal having a predetermined number of pixels is output, scanning of the shift register is stopped and analog output is stopped at time t16. However, since the synchronization signal SYNC is not input after time t17, the output of the remaining analog signals cannot be resumed, and the image of the last frame is discarded.

  In view of the above problems, an object of the present invention is to enable output of all radiation images while realizing radiation imaging at a high frame rate.

A radiation imaging apparatus according to the present invention that achieves the above object is as follows.
Synchronization signal detection means for detecting the synchronization signal;
An imaging request signal detecting means for detecting an imaging request signal indicating that a series of imaging periods are being performed at an imaging interval according to the synchronization signal;
Storage means for converting and storing radiation irradiated at the imaging interval into an electrical signal;
Output means for sampling and holding the electrical signal and outputting it as an analog signal for each pixel circuit;
When the frame rate based on the imaging interval exceeds a reference value, the output means temporarily stops output after outputting a predetermined number of pixels in the pixel circuit,
When the imaging request signal is not detected after the output is paused, the output is resumed for the remaining pixel circuits.

  According to the present invention, it is possible to output all radiation images while realizing radiation imaging at a high frame rate.

1 is a schematic block diagram showing an entire radiation moving image capturing apparatus system according to an embodiment of the present invention. The figure which showed typically the internal structure of the rectangular semiconductor substrate which concerns on one Embodiment of this invention. 4 is a timing chart showing an example of image reading according to an embodiment of the present invention. 1 is an equivalent circuit for one pixel of a rectangular semiconductor substrate according to an embodiment of the present invention. The timing chart of the rectangular semiconductor substrate control signal concerning one embodiment of the present invention. The flowchart which shows the control procedure of the rectangular semiconductor substrate which concerns on one Embodiment of this invention. The timing chart of the conventional rectangular semiconductor substrate control signal.

(First embodiment)
With reference to FIG. 1, the typical block showing the whole large area flat panel radiographic imaging system is demonstrated. The radiation moving image imaging system includes a radiation imaging apparatus 100, an image processing / system control apparatus 101, an image display apparatus 102, a radiation generation control apparatus 103, and a radiation tube 104. During imaging, the image processing / system control apparatus 101 controls the radiation imaging apparatus 100 and the radiation generation control apparatus 103 synchronously. The radiation that has passed through the subject is converted into visible light by a scintillator (not shown), and after A / D conversion is performed according to photoelectric conversion corresponding to the amount of light. Then, after A / D conversion, frame image data corresponding to radiation irradiation is transferred from the radiation imaging apparatus 100 to the image processing / system control apparatus 101. After the image processing is performed, the radiation image is displayed on the image display device 102 in real time.

  The radiation imaging apparatus 100 includes a flat panel sensor 106. In the flat panel sensor 106, a rectangular semiconductor substrate 107 obtained by two-dimensionally cutting photoelectric conversion elements from a silicon semiconductor wafer into a strip shape is tiled in a matrix of 14 columns × 2 rows on a flat base (not shown). ing. On the upper side and the lower side of the flat panel sensor 106, external terminals (electrode pads) (not shown) provided on the rectangular semiconductor substrate 107 arranged in a matrix are arranged in a line. The electrode pads provided on the rectangular semiconductor substrate 107 are connected to an external circuit by a flying lead type printed wiring board (not shown). The analog multiplexers 131 to 138 select pixel outputs of the connected rectangular semiconductor substrate 107 based on a control signal from the imaging unit control circuit 108. Then, output is performed to the differential amplifiers 141 to 148 connected to the analog multiplexers 131 to 138, respectively. The A / D converter 151 to A / D converter 158 are differential amplifiers to which the A / D converter 151 to A / D converter 158 are connected in accordance with the synchronous clock output from the imaging unit control circuit 108. The analog signals from 141 to the differential amplifier 148 are digitized and output to the imaging unit control circuit 108. The imaging unit control circuit 108 synthesizes digital image data for each block A / D converted by the A / D converter 151 to A / D converter 158 into frame data, and performs image processing / system control via the connection unit 109. Transfer to device 101.

  The rectangular semiconductor substrate 107 cut out in a strip shape is, for example, a substrate having a width of about 20 mm and a length of about 140 mm. Further, the flat panel sensor 106 configured by being tiled in a matrix of 14 columns × 2 rows is, for example, a square of about 11 inches square with a length of about 280 mm and a width of about 280 mm.

  Next, the internal structure of the rectangular semiconductor substrate 107 will be described with reference to FIG. A timing chart illustrating an example of image reading processing from the flat panel sensor 106 on which the rectangular semiconductor substrate 107 is tiled will be described with reference to FIG.

  In FIG. 2, the rectangular semiconductor substrate 107 includes a pixel circuit 201, a vertical shift register 202, and a horizontal shift register 203. The row control signal 204 is a signal in the row direction, and the column control signal 205 is a signal in the column direction.

  The pixel circuit 201 is a pixel circuit including photoelectric conversion elements that are two-dimensionally aligned on the rectangular semiconductor substrate 107. The vertical shift register 202 and the horizontal shift register 203 function as a read control circuit. A horizontal shift register start signal HST, a vertical shift register start signal VST, a horizontal shift clock signal CLKH, and a vertical shift clock signal CLKV are input from external terminals.

  In the time chart of FIG. 3, when the vertical shift clock signal CLKV rises while the vertical shift register start signal VST is “HIGH”, the internal circuit of the vertical shift register 202 is reset. Then, “HIGH” is output to the output V 0 of the vertical shift register 202, and one line of pixel output controlled by the row control signal 204 becomes valid. Further, when the horizontal shift clock signal CLKH rises while the horizontal shift register start signal HST is “HIGH”, the circuit inside the horizontal shift register 203 is reset. Then, “HIGH” is output to the output H0 of the horizontal shift register 203, and the output of the pixel circuit 201 selected by H0 among the pixels of one line enabled by the row control signal 204 is output to the analog output terminal. The The horizontal shift clock signal CLKH pulse is sequentially input, and the “HIGH” output of the horizontal shift register 203 is sequentially shifted to H0, H1,..., H126, H127, and the reading of one line is completed. Next, the vertical shift clock signal CLKV is input, and the “HIGH” output of the vertical shift register 202 is switched to V1. Thereafter, the pixel output of one line controlled by the row control signal 204 becomes valid, and the pixel is read out. These operations are sequentially repeated to read out pixels from the entire rectangular semiconductor substrate 107.

  Since the pixel values of the rectangular semiconductor substrate 107 are sequentially output to the external analog output terminal in synchronization with the horizontal shift clock signal CLKH, the A / D converter 151 to A / D converter 158 are synchronized with the horizontal shift clock signal CLKH. A / D conversion is performed by the A / D conversion clock CLKAD.

  FIG. 4 is a circuit diagram for one pixel of a tiled rectangular semiconductor substrate. In FIG. 4, the switching MOS transistor 301 resets the photodiode 302 and the floating diffusion capacitor 310 by applying a reset voltage VRES. The switching MOS transistor 303 activates the MOS transistor 314 that functions as a floating diffusion amplifier, and the switching MOS transistor 313 activates the MOS transistor 315 that functions as a source follower amplifier. The switch MOS transistor 304 can be combined with a clamp capacitor (capacitor 305) to form a clamp circuit and remove kTC noise (reset noise) generated in the photodiode 302. The switch MOS transistor 306 performs sample hold of the signal voltage corresponding to the light amount, and the switch MOS transistor 307 performs sample hold of the clamp voltage VCL. When the switching MOS transistor 306 is turned on, the capacitor 308 accumulates electric charges. The capacitor 308 accumulates charges obtained by adding a noise component and a dark current component to the voltage of the photodiode 302. When the switch MOS transistor 307 is turned on, the capacitor 309 accumulates electric charges. The capacitor 309 stores the clamp voltage VCL, that is, the charge of the noise component and the dark current component. By subtracting the charge accumulated in the capacitor 309 from the charge accumulated in the capacitor 308, a voltage (electric signal) corresponding to the light amount of the photodiode 302 can be obtained. This subtraction is performed by the differential amplifier 141 to the differential amplifier 148.

  However, the pixel value data obtained from the rectangular semiconductor substrate 107 includes a noise component of the photodiode 302 that cannot be excluded by subtracting the charge accumulated in the capacitor 309 from the charge accumulated in the capacitor 308. Therefore, it is known that pixel value data captured without irradiation with radiation is fixed pattern noise (FPN) and correction is performed using the FPN image.

  Here, with reference to FIG. 5, a sampling operation in the case of capturing a moving image by intermittently irradiating a subject with radiation in a pulse shape will be described.

  In FIG. 5, the synchronization signal SYNC is input from the image processing / system control apparatus 101 to the radiation imaging apparatus 100 at time t1 (synchronization signal detection). The interval at which the synchronization signal SYNC is input is the moving image imaging interval FT. In addition to the synchronization signal SYNC, an imaging request signal EXP_REQ indicating that a series of imaging periods with an imaging interval corresponding to the synchronization signal is in progress is input (imaging request signal detection). If the imaging request signal EXP_REQ is High, the imaging operation is performed in synchronization with the synchronization signal SYNC.

  The image processing / system control apparatus 101 controls the radiation imaging apparatus 100 and sets the EN signal to High at time t2 to start the accumulation of radiation, thereby switching MOS transistor 303 (EN signal) and switching MOS transistor. 313 is turned on. Then, the pixel circuit on the sensor chip is started, and the switch MOS transistor 301 is turned on by setting the PRES signal to High. Then, the reset voltage VRES is applied to the floating diffusion capacitor 310 to reset the sensor.

  Subsequently, the image processing / system control apparatus 101 controls the radiation imaging apparatus 100 to release the reset by turning off the switching MOS transistor 301 (PRES signal) at time t3, and then sends the PCL signal High. As a result, the switching MOS transistor 304 is turned on, and the clamp voltage VCL is applied to the capacitor 305.

  The image processing / system control apparatus 101 controls the radiation imaging apparatus 100 to turn off the switching MOS transistor 303 (EN signal) and the switching MOS transistor 304 (PCL signal) at time t4, thereby enabling the pixel processing. The reset operation is terminated, accumulation in the photodiode 302 is started, and the radiation exposure A becomes effective.

  The radiation is irradiated to the subject with a pulse of a predetermined time. Therefore, in order to minimize the influence of the noise component of the photodiode 302, the accumulation is terminated when the time corresponding to the irradiation time has elapsed.

  Therefore, the image processing / system control apparatus 101 sets the EN signal to High again at time t5 to turn on the switching MOS transistor 303 and the switching MOS transistor 313, and activates the pixel circuit on the sensor chip. Then, by setting the TS signal to High, the switching MOS transistor 306 is turned on, and the voltage of the photodiode 302 is sampled and held in the capacitor 308.

  The image processing / system control apparatus 101 ends the sample hold by turning off the switching MOS transistor 306 (TS signal) at time t6, and invalidates the radiation exposure A. Subsequently, the switch MOS transistor 301 is turned on by setting the PRES signal to High, and the reset voltage VRES is applied to the floating diffusion capacitor 310 to reset the sensor.

  The image processing / system control apparatus 101 turns off the switching MOS transistor 301 (PRES signal) at time t7, then turns the PCL signal high to turn on the switching MOS transistor 304, and the capacitor 305 A voltage of the clamp voltage VCL is applied. Subsequently, by setting the TN signal to High, the switching MOS transistor 307 is turned on, and the clamp voltage VCL is sampled and held in the capacitor 309.

  At time t8, the image processing / system control apparatus 101 turns off the switching MOS transistor 307 (TN signal), the switching MOS transistor 304 (PCL signal), the switching MOS transistor 303, and the switching MOS transistor 313 (EN signal). The sample-and-hold is terminated by setting the state.

  As a result of the above sampling operation, current flows through all the pixels of the rectangular semiconductor substrate and the power supply voltage of the rectangular semiconductor substrate fluctuates. Then, by scanning the vertical shift register 202 and the horizontal shift register 203 from time t9 to time t10, the voltage sampled and held by the capacitor 308 and the capacitor 309 is sequentially output to the outside by a predetermined number of pixels for each pixel circuit ( Scan A1). Scanning of the shift register is temporarily stopped at time t10. Specifically, the vertical shift register start signal VST, the vertical shift clock signal CLKV, the horizontal shift register start signal HST, and the horizontal shift clock signal CLKH input to the vertical shift register 202 and the horizontal shift register 203 are stopped. Thus, the output of the pixel signal is temporarily stopped.

  At time t9, the imaging request signal EXP_REQ is High and is not the final frame, so the input of the synchronization signal SYNC is awaited.

  When the synchronization signal SYNC of the second frame is input from the image processing / system control apparatus 101 to the radiation imaging apparatus 100 at time t11, the reset operation is performed from time t12 to time t13, and the power supply voltage resulting from the reset operation is increased. The system waits until the fluctuations converge, and restarts the remaining pixel output at time t14 (scan A2), and ends the remaining pixel output at time t15.

  After a predetermined accumulation time has elapsed, sample hold is performed from time t16 to time t17, pixel output for a predetermined number of pixels is performed from time t18 to time t19, and paused (scan B1). Since it is detected that the imaging request signal EXP_REQ is High at time t19, input of the synchronization signal SYNC of the third frame is awaited until time t20.

  Thereafter, similarly, at time t27, the image data of the third frame is output up to a predetermined number of pixels and temporarily stopped (scanning C1). Since it is detected that the imaging request signal EXP_REQ is Low at time t28, it is determined that the current frame is the final frame, and the output of the remaining pixels is restarted (scan C2). At time t29, the output of all pixels in the third frame, which is the final frame, is completed. As a result, it is possible to output the image of the final frame, and it is possible to avoid invalid exposure.

  In the example of FIG. 5, for the sake of simplicity, a timing chart when imaging is completed in three frames is shown, but the timing chart is not limited to imaging in three frames. Further, although the case where both the synchronization signal SYNC and the imaging request signal EXP_REQ are positive logic is described, the present invention is not limited to this.

  Furthermore, it is determined whether or not the imaging is finished after pausing after outputting the predetermined number of pixels, but at any timing from the detection of the synchronization signal SYNC to the pausing by outputting the predetermined number of pixels The determination may be made.

  Next, a procedure for the radiation imaging apparatus 100 according to the present embodiment to perform the processing shown in FIG. 5 will be described with reference to the flowchart of FIG.

  In step S <b> 601, the radiation imaging apparatus 100 receives an imaging mode setting from the image processing / system control apparatus 101 and starts operation.

  In S602, the radiation imaging apparatus 100 determines the imaging interval FT of the synchronization signal that is minimized based on the imaging mode set in S601, and the scanning time ST necessary to scan the pixel circuits for all pixels, It is determined whether the sum of the accumulation time XT necessary for accumulating the irradiated radiation is larger than the imaging interval FT, that is, whether the frame rate based on the imaging interval FT exceeds the reference value. If it is determined that ST + XT> FT (S602; YES), the process proceeds to S603. On the other hand, if it is determined that ST + XT ≦ FT (S602; NO), the process proceeds to S612.

  In step S <b> 603, the radiation imaging apparatus 100 determines whether the synchronization signal SYNC is input from the image processing / system control apparatus 101. When it is determined that the synchronization signal SYNC is input (S603; YES), the process proceeds to S604. On the other hand, when it is determined that the synchronization signal SYNC is not input (S603; NO), the process waits until it is input. In the example of FIG. 5, the synchronization signal SYNC of the first frame is input at time t1, and the process proceeds to S604.

  In S604, the radiation imaging apparatus 100 executes a reset operation of all the pixel circuits and starts accumulation. This makes radiation exposure effective. In the example of FIG. 5, the pixel reset operation is executed from time t2 to time t4, and the radiation exposure A becomes effective at time t4.

  In step S <b> 605, the radiation imaging apparatus 100 performs sample holding after a predetermined accumulation time XT corresponding to the radiation irradiation time has elapsed, and starts outputting pixel signals. In the example of FIG. 5, after the accumulation time XT from time t4 to time t5 due to radiation exposure A has elapsed, pixel sample hold is performed from time t5 to time t8.

  In S606, the radiation imaging apparatus 100 scans the vertical shift register 202 and the horizontal shift register 203 to output a predetermined number of pixels, and then temporarily stops the output (in the example of FIG. 5, from time t9 to time t10). Scan A1).

  In step S <b> 607, the radiation imaging apparatus 100 determines whether the image for which output has been stopped is the last frame based on the imaging request signal EXP_REQ illustrated in FIG. 5. Specifically, when the imaging request signal EXP_REQ is Low, it is determined that the frame is the last frame, and even if the synchronization signal SYNC is subsequently input, it is ignored. On the other hand, when the imaging request signal EXP_REQ is High The imaging is performed in synchronization with the input synchronization signal SYNC. When it is determined that it is the last frame (S607; YES), the process proceeds to S608. On the other hand, when it is determined that it is not the last frame (S607; NO), the process proceeds to S609. In the example of FIG. 5, since the imaging request signal EXP_REQ is High at time t10, it is determined that it is not the last frame, so the process proceeds to S609 and waits for the input of the synchronization signal SYNC.

  In step S609, the radiation imaging apparatus 100 determines whether the synchronization signal SYNC is input. When it is determined that the synchronization signal SYNC is input (S609; YES), the process proceeds to S610. On the other hand, when it is determined that the synchronization signal SYNC is not input (S609; NO), the process waits until it is input. In the example of FIG. 5, the synchronization signal SYNC of the first frame is input at time t11, and the process proceeds to S610.

  In step S610, the radiation imaging apparatus 100 performs a reset operation for all pixels and starts accumulation. This makes radiation exposure effective. In the example of FIG. 5, the pixel reset operation is executed from time t12 to time t13, and the radiation exposure B is enabled at time t13.

  In step S <b> 611, the radiation imaging apparatus 100 outputs the remaining pixels that have been temporarily stopped after a predetermined time has elapsed. In the example of FIG. 5, from time t13 to time t14, waiting for a predetermined time until the power supply voltage fluctuation is settled by the reset operation, the remaining pixel output is started at time t14 after the predetermined time has elapsed, and The pixel output is completed (scan A2). Thereafter, the process returns to S605.

  In step S <b> 605, the radiation imaging apparatus 100 performs sample holding after a predetermined accumulation time XT corresponding to the radiation irradiation time has elapsed, and starts outputting pixel signals. In the example of FIG. 5, after the accumulation time XT from time t13 due to radiation exposure B has elapsed, pixel sample hold is performed from time t16 to time t17.

  In S606, the radiation imaging apparatus 100 scans the vertical shift register 202 and the horizontal shift register 203 to output a predetermined number of pixels, and then temporarily stops the output (in the example of FIG. 5, from time t18 to time t19). Scan B1).

  In step S <b> 607, the radiation imaging apparatus 100 determines whether the image for which output has been stopped is the last frame based on the imaging request signal EXP_REQ illustrated in FIG. 5. In the example of FIG. 5, since the imaging request signal EXP_REQ is also High this time, the process proceeds to S609 and waits for the input of the third frame synchronization signal SYNC until time t20.

  Thereafter, similarly, at time t27, the image data of the third frame is output up to a predetermined number of pixels and temporarily stopped (scanning C1). Since the imaging request signal EXP_REQ is Low at time t28, it is determined that the third frame is the final frame (607; YES), and the process proceeds to S608.

  In step S608, the radiation imaging apparatus 100 resumes output of the remaining pixels. In the example of FIG. 5, the output of all the pixels in the third frame, which is the final frame, ends at time t29 (scan C2).

  On the other hand, since the process of S612-S614 is the same as the process of S603-S605, description is abbreviate | omitted. In step S615, the radiation imaging apparatus 100 scans the vertical shift register 202 and the horizontal shift register 203 and outputs all the numbers of pixels.

  In S616, the radiation imaging apparatus 100 determines whether the current image is the last frame based on the imaging request signal EXP_REQ. Specifically, when the imaging request signal EXP_REQ is Low, it is determined that it is the last frame, and when the imaging request signal EXP_REQ is High, it is determined that it is not the final frame. If it is determined that it is the last frame (S616; YES), the process is terminated. On the other hand, when it is determined that the frame is not the last frame (S616; NO), the process returns to S612. Thus, each process of the flowchart of FIG. 6 ends.

  As described above, according to the present embodiment, it is possible to output all radiation images while realizing radiation imaging at a high frame rate.

  In the first embodiment, a method has been described in which, after a predetermined number of pixels have been output, the imaging request signal EXP_REQ is confirmed almost in a short time, and output of the remaining pixels is resumed. On the other hand, the time until the synchronization signal SYNC uniquely determined by the imaging interval FT is detected after the output of the predetermined number of pixels is temporarily stopped, the time required for the reset operation, and the fluctuation of the power supply voltage due to the reset operation is settled. After the elapse of time, the output of the remaining pixels may be resumed. As a result, the output cycles of all frames can be made equal.

  In addition, if the image that is currently output after being paused after the output of the predetermined number of pixels is the last frame, after the predetermined time uniquely determined by the imaging interval FT has elapsed, it is actually during the time required for the reset operation. Alternatively, the reset operation may be executed, and the output of the remaining pixels may be resumed after a lapse of a predetermined time until the voltage fluctuation due to the reset operation is settled. Thereby, not only the output cycle of all the frames becomes substantially constant, but also the condition of the power supply voltage at the time of reading analog data can be made the same.

  In the first embodiment, it has been described that the synchronization signal SYNC stops after the synchronization signal SYNC of the last frame is input. On the other hand, when the imaging request signal EXP_REQ indicates the end of imaging after temporarily stopping after outputting the predetermined number of pixels without controlling only the imaging request signal EXP_REQ and stopping the synchronization signal SYNC, the synchronization signal SYNC It may be configured to wait for an input, wait for the elapse of a predetermined time until the power supply voltage fluctuation due to the reset operation and the reset operation is settled after detecting the synchronization signal SYNC, and resume the output of the remaining pixels. As a result, the output cycles of all frames can be made equal. Further, by actually performing reset driving, not only the output cycle of all frames becomes substantially constant, but also the condition of the power supply voltage at the time of reading analog data can be made the same.

  In the first embodiment, the final frame is determined using the imaging request signal EXP_REQ. However, it is also possible to determine the end of imaging based on the imaging interval FT according to the set imaging mode.

  Further, after the analog output is temporarily stopped, the output of the remaining pixels may be resumed when a time exceeding the imaging interval estimated from the set imaging mode has elapsed.

  Also, if the imaging request signal is not detected after the analog output is paused, the output of the remaining pixels can be resumed when the time exceeding the imaging interval has elapsed since the synchronization signal was previously detected. Good.

  In addition, the radiation imaging apparatus 100 can take a plurality of states such as a power saving state, an imaging preparation state, and an imaging ready state, and the imaging mode and the state of the radiation imaging apparatus 100 are changed from the image processing / system control device 101 to You may further provide the command communication part (not shown) which receives the command for making it change from a state to a 2nd state.

  When the radiation imaging apparatus 100 pauses the output after outputting a predetermined number of pixels, for example, when the command communication unit receives a transition command from the imaging ready state to the imaging preparation state or the power saving state, the remaining pixels May be resumed, and after all pixel data output is completed, transition to the instructed state may be made.

  Thereby, it becomes possible to output all captured image data regardless of the state of the imaging request signal EXP_REQ and the synchronization signal SYNC.

(Other embodiments)
The present invention can also be realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, or the like) of the system or apparatus reads the program. It is a process to be executed.

Claims (8)

Synchronization signal detection means for detecting the synchronization signal;
An imaging request signal detecting means for detecting an imaging request signal indicating that a series of imaging periods are being performed at an imaging interval according to the synchronization signal;
Storage means for converting and storing radiation irradiated at the imaging interval into an electrical signal;
Output means for sampling and holding the electrical signal and outputting it as an analog signal for each pixel circuit;
When the frame rate based on the imaging interval exceeds a reference value, the output means temporarily stops output after outputting a predetermined number of pixels in the pixel circuit,
The radiation imaging apparatus according to claim 1, wherein when the imaging request signal is not detected after the output is temporarily stopped, the output is resumed for the remaining pixel circuits.   When the imaging request signal is detected after the output is temporarily stopped, the output means restarts the output for the remaining pixels after a predetermined time in response to the next detection of the synchronization signal. The radiation imaging apparatus according to claim 1.   The frame rate is equal to the reference value when the sum of the electrical signal accumulation time by the accumulation means and the time required for the output means to output all the pixel circuits is longer than the imaging interval. The radiation imaging apparatus according to claim 1 or 2, wherein   When the imaging request signal is no longer detected after the output is temporarily stopped, the output means determines the time until the next synchronization signal uniquely determined by the imaging interval is detected and the reset operation of the storage means. 4. The output of the remaining pixel circuit is restarted after a time required and a time required for the fluctuation of the power supply voltage caused by the reset operation to converge have elapsed. The radiation imaging apparatus according to item 1.   The output means outputs the remaining pixels when the imaging request signal is no longer detected after pausing the output, or when a time exceeding the imaging interval has elapsed since the synchronization signal was previously detected. The radiation imaging apparatus according to claim 1, wherein the radiation imaging apparatus is restarted. Command communication means for receiving a command for causing the radiation imaging apparatus to transition from the first state to the second state;
The output means, after temporarily stopping the output, when the command communication means receives a command for transitioning from the imaging ready state as the first state to the imaging preparation state as the second state, 6. The radiation imaging apparatus according to claim 1, wherein output is resumed for the remaining pixels. A method for controlling a radiation imaging apparatus comprising a synchronization signal detection means, an imaging request signal detection means, a storage means, and an output means,
A synchronization signal detecting step in which the synchronization signal detecting means detects a synchronization signal;
An imaging request signal detection step of detecting an imaging request signal indicating that the imaging request signal detection means is in a series of imaging periods with an imaging interval according to the synchronization signal;
An accumulating step in which the accumulating means converts the radiation irradiated at the imaging interval into an electrical signal and accumulates;
The output means has an output step of sampling and holding the electrical signal and outputting it as an analog signal for each pixel circuit;
In the output step, when the frame rate based on the imaging interval exceeds a reference value, the output is temporarily stopped after outputting a predetermined number of pixels in the pixel circuit,
A method for controlling a radiation imaging apparatus, wherein output is resumed for the remaining pixel circuits when the imaging request signal is no longer detected after the output is temporarily stopped.   The program for functioning a computer as each means of the radiation imaging device of any one of Claims 1 thru | or 6.

Images