Imaging apparatus, imaging method, and storage medium

Abstract

The object of this invention is to provide an imaging apparatus capable of providing a high-quality image optimum for medical diagnosis or the like by an arrangement for preventing any degradation in image quality due to the influence of electromagnetic noise and vibration caused by grid movement. In order to achieve this object, as operation control in receiving radiation transmitted through an object by an image sensing element through a movable grid and reading the accumulated signal from the image sensing element, a control device stops moving drive movement of the grid after the end of radiation irradiation for the object, and after the stop of moving drive stopping the movement, starts reading the accumulated signal from the image sensing element.

Description

control before

Operation control until radiation irradiation is determined from these initial conditions.

Next, control timings for sensor initialization, start of grid movement, and irradiation permission instruction after recognition of the imaging request are determined by subtracting a corresponding time required for operation from the irradiation delay time T1.
Sensor initialization timing: T1−Tss=100 ms
Grid movement start timing: T1−Tgs=0 ms
Irradiation enable signal transmission timing: T1−Txs=200 ms

Control timings after radiation irradiation are so determined that movement control for the grid 104 is stopped after the elapse of actual irradiation time obtained by adding the irradiation time T exp and post-irradiation delay time Txe to the irradiation delay T1, and the signal read from the sensor 106 is started after the elapse of grid vibration convergence time Tge.

That is, the grid control stop timing and signal read start timing are determined by
Grid control stop timing: T1+T exp+Txe=500 ms
Signal read start timing: T1+T exp+Txe+Tge=800 ms

After the control timings are determined, an imaging request (FIG. 3A) input by the user by pressing the imaging button 116 is waited control before

Operation control until radiation irradiation is determined from these initial conditions.

Next, control timings for sensor initialization, start of grid movement, and irradiation permission instruction after recognition of the imaging request are determined by subtracting a corresponding time required for operation from the irradiation delay time T1.
Sensor initialisation timing: T1−Tss=100 ms
Grid movement start timing: T1−Tgs=0 ms
Irradiation enable signal transmission timing: T1−Txs=200 ms

After the control timings are determined, an imaging request (FIG. 6A) input by the user by pressing the imaging button 116 is waited readupon while repeating the pre-read operation.

When an exposure request is generated, the pre-read operation is performed again to prepare for image acquisition, and X-ray exposure is waited. When preparation for image acquisition is completed, X-ray exposure is executed in accordance with an instruction from the image sensing controller 24.

After X-ray exposure, signal charges are read from the photoelectric conversion elements 80. First, the voltage Vgh is applied to the row selection line Lr of a certain row (e.g., Lr1) of the photoelectric conversion element array to output accumulated charge signals to the signal lines Lc1 to Lc4096. Signals of 4,096 pixels are simultaneously read from the column signal lines Lc1 to Lc4096 in units of columns.

Next, the voltage Vgh is applied to another row selection line Lr (e.g., Lr2) to output accumulated charge signals to the signal lines Lc1 to Lc4096. Signals of 4,096 pixels are simultaneously read from the column signal lines Lc1 to Lc4096 in units of columns. All pieces of image information are read by sequentially repeating this operation for the 4,096 column signal lines.

During the operation, the charge accumulation time of each sensor corresponds to a time after the reset operation is ended, i.e., the TFT 82 in the pre-read mode is turned off until the TFT 82 is turned on to read charges. Hence, the accumulation time and timing change for each row selection.

After an X-ray image is read, a correction image is acquired. This correction data is necessary to acquire a high-quality image and is used to correct the X-ray image. The basic image acquisition procedure is the same as described above except that no X-ray exposure is performed. The charge accumulation time in reading the X-ray image equals that in reading the correction image.

When high-resolution image information is unnecessary, or the image data read speed need be high, all pieces of image information need not always be read. In accordance with the imaging method selected by the operator 21, the image sensing controller 24 sets a drive instruction of thinning, pixel averaging, or region extraction for the driver 62.

To thin the image data, first, the row selection line Lr1 is selected, and in outputting signals from the column signal lines Lc, signal charges are read from one column while incrementing, e.g., n of Lc2n−1 (n: natural number) one by one from 0. After that, signals are read from one row while incrementing m of Lr2m−1 (m: natural number) one by one from 1. In this example, the number of pixels is thinned to 1/4. The driver 62 thins the number of pixels to 1/9, 1/16, or the like in accordance with a setting instruction from the image sensing controller 24.

For pixel averaging, when the voltage Vgh is simultaneously applied to row selection lines Lr2m and Lr2m+1 during the above-described operation, TFTs 2m and 2n and TFTs 2m+1 and 2n are simultaneously turned on, so that analog addition of two pixels in the column direction can be performed. This means that not only addition of two pixels but also analog addition of a puerility plurality of pixels in the column signal line direction can be easily performed. For addition in the row direction, when adjacent pixels (Lc2n and Lc2n+1) are digitally added after A/D conversion output, the sum of 2×2 square pixels can be obtained together with the above analog addition. Hence, the data can be read at a high speed without wasting the X-ray irradiation.

As another method of decreasing the total number of pixels to increase the read speed, the image read region is limited. To do this, the operator 21 inputs a necessary region from the operator interface 22, the image sensing controller 24 issues an instruction to the driver 62 on the basis of the input region, and the driver 62 changes the data read range and drives the two-dimensional detector array.

In this embodiment, in the high-speed read mode, 1,024×1,024 pixels are read at 30 F/S. That is, in the entire region of the two-dimensional detector array, addition processing of 4×4 pixels is performed to thin the number of pixels to 1/16, and in the smallest range, an image is sensed in a 1,024×1,024 range without thinning. With this image sensing, a digital zoom image can be obtained.

FIG. 13 is a timing chart including image sensing operation of the X-ray detector 52. The operation of the X-ray detector 52 will be described mainly with reference to FIG. 13.

Reference numeral 701 denotes an image sensing request signal to the operator interface 22; 702, an actual X-ray exposure state; 703, an imaging request signal from the image sensing controller 24 to the driver 62 on the basis of an instruction from the operator 21; 704, an imaging ready signal of the X-ray detector 52; 705, a drive signal for the grid 54; 706, a power control signal in the X-ray detector 52; 707, a driven state of the X-ray detector (especially charge read operation from the photodetector array 58); and 708, an image processing or display state.

Until a detector preparation request or imaging request is input by the operator 21, the driver 62 stands by in a power control off state, as indicated by 706. More specifically, referring to FIG. 11, the row selection lines Lr, column signal lines Lc, and bias line Lb are kept at an equipotential state (especially signal GND level) by a switch (not shown), and no bias is applied to the photodetector array 58. Alternatively, power supply including the signal read circuit 100, line selector 92, and bias power supply 84 or 85 may be cut off to keep the row selection lines Lr, column signal lines Lc, and bias line Lb at the GND potential.

In accordance with an imaging preparation request instruction (701: 1st SW) from the operator 21 to the operator interface 22, the image sensing controller 24 outputs an instruction to shift the X-ray generator 40 to an imaging ready state and shift the X-ray detector 52 to an imaging preparation state. Upon receiving the instruction, the driver 62 applies a bias to the photodetector array 58 and repeats (refresh and) pre-read Fi. The request instruction is, e.g., the 1st SW of the exposure request switch to the X-ray generator (normally, rotor up for the tube or the like is started) or, when a predetermined time (several sec or more) is required by the X-ray detector 52 for imaging preparation, an instruction for starting preparation of the X-ray detector 52.

In this case, the operator 21 need not consciously issue the imaging preparation request instruction to the X-ray detector 52. That is, when patient information or imaging information is input to the operator interface 22, the image sensing controller 24 may interpret it as a detector preparation request instruction and shift the X-ray detector 52 to the detector preparation state.

In the detector preparation state, in the photoelectric conversion mode, to prevent a dark current from being gradually accumulated in the photodetection section 80 after the pre-read and the capacitor 80b (80c) from being held in the saturated state, the (refresh R and) pre-read Fi is repeated at a predetermined interval. This driving performed in the period when no actual X-ray exposure request is generated although the imaging preparation request from the operator 21 has been received, i.e., driving in which the pre-read Fi performed in the detector preparation state is repeated at a predetermined time interval T1 will be referred to as “idling drive” hereinafter. The period when the idling drive is performed in the detector preparation state will be referred to as an “idling drive period” hereinafter. How long the idling drive period continues is undefined in practical use. To minimize the read operation with load on the photodetector array 58 (especially the TFTs 82), the time interval T1 is set to be longer than that in the normal imaging operation, and the pre-read Fi dedicated to idling for which the ON time of the TFTs 82 is shorter than that in a normal read drive Fr. For a sensor that requires the refresh R, the refresh R is performed once for several times of pre-read Fi.

X-ray image acquisition mainly performed by the X-ray detector 52 will be described next.

Drive of the X-ray detector 52 in acquiring an X-ray image is mainly comprised of two image acquisition cycles. As indicated by 707, one is X-ray image acquisition drive, and the other is correction dark image acquisition drive. The drive cycles are almost the same except whether X-ray exposure operation is performed. Each drive cycle has three parts: an image sensing preparation sequence, charge accumulation (exposure window), and image read.

X-ray image acquisition will be described below in accordance with the sequence.

In accordance with an imaging request instruction (701: 2nd SW) from the operator 21 to the operator interface 22, the image sensing controller 24 controls imaging operation while synchronizing the X-ray generator 40 with the X-ray detector 52. In accordance with the imaging request instruction (701: 2nd SW), an imaging request signal is asserted provided to the X-ray detector at a timing represented by the X-ray exposure request signal 703. The driver performs predetermined image sensing preparation sequence drive operations as indicated by the imaging driven state 707 in response to the imaging request signal. More specifically, if the refresh is necessary, the refresh is performed. Then, a pre-read FR dedicated to the imaging sequence is performed a predetermined number of times, and a pre-read Fpf dedicated to the charge accumulation state is performed to shift the state to the charge accumulation state (image sensing window: T4).

The number of times and time interval T2 of the pre-read Fp for the image sequence are based on values preset prior to the imaging request from the image sensing controller 24. Optimum drive is automatically selected depending on the image sensing portion or whether the request from the operator 21 represents priority on the operability or image quality. A period (T3) from the exposure request to the end of imaging preparation is required to be short in practical use. Hence, the pre-read Fp dedicated to the image sensing preparation sequence is performed. In addition, independently of the state of idling drive, when an exposure request is generated, the image sensing preparation sequence drive is immediately started to shorten the period (T3) from the exposure request to the end of imaging preparation, thereby improving the operability.

In synchronism with the image sensing preparation of the photodetector array 58, the driver 62 starts moving the grid 54 to sense an image while setting the grid in an optimum moving state in synchronism with the actual X-ray exposure 702. In this case as well, the driver 62 operates on the basis of an optimum grid moving start timing and optimum grid moving speed that are set by the image sensing controller.

In this embodiment, to eliminate the influence of vibration by the operation of the grid 54, the start of movement of the grid 54 is controlled such that a change in acceleration becomes small. In addition, in executing the pre-read Fpf dedicated to the charge accumulation state, which is readily affected by vibration, the grid 54 is controlled to exhibit uniform motion (still state or motion at uniform speed).

When image sensing preparation of the X-ray detector 52 is ended, the driver 62 returns the X-ray detector ready signal 704 to the image sensing controller 24. On the basis of this signal transition, the image sensing controller 24 asserts provides the X-ray generation request signal 702 to the X-ray generator 40. The X-ray generator 40 generates X-rays while receiving the X-ray generation request signal 702. When a predetermined amount of X-rays is generated, the image sensing controller 24 negates the X-ray generation request signal 702, thereby notifying the X-ray detector 52 of the image acquisition timing. On the basis of this timing, the driver 62 immediately stops the grid 54 and starts operating the signal read circuit 100 that has been in the standby state. After the OFF time of the grid 54 and a predetermined wait time to stabilize the signal read circuit 100, when operation of reading image data from the photodetector array 58 and acquiring a raw image for the image processor 26 on the basis of the driver 62 is ended, the driver 62 shifts the signal read circuit 100 to the standby state again.

In this embodiment, to eliminate the influence of vibration by the operation of the grid 54, the grid 54 is controlled to exhibit uniform motion (including the still state) before drive of an X-ray image acquisition frame Frxo that is most readily affected by vibration noise. Alternatively, a vibration sensor for measuring vibration may be attached to the X-ray detector 52, and the drive of the X-ray image acquisition frame Frxo may be started after confirming that the vibration by the grid or other factors has converged to a predetermined or less value.

Subsequently, the X-ray detector 52 acquires a correction image. That is, the above imaging sequence for imaging is repeated to acquire a dark image without X-ray irradiation, and the correction dark image is transferred to the image processor 26.

In the image sensing sequence, the X-ray exposure time or the like may slightly change between imaging cycles. However, when the same image sensing sequence is reproduced, including such differences, to acquire a rough image, an image with a higher quality can be obtained. However, the operation of the grid 54 is not limited to this. The grid 54 may be set still to suppress the influence of vibration in acquiring the rough image. In this case, after the image is almost acquired, the grid 54 is initialized at a predetermined timing that does not affect the image quality.

FIG. 14 is a block diagram showing the flow of image data in the image processor 26. Reference numeral 801 denotes a multiplexer for selecting a data path; 802 and 803, X-ray image and rough image frame memories; 804, an offset correction circuit; 805, a gain correction data frame memory; 806, a gain correction circuit; 807, a defect correction circuit; and 808, other image procession circuits.

An X-ray image acquired by the X-ray image acquisition frame Frxo in FIG. 13 is stored in the X-ray image frame memory 802 through the multiplexer 801. A correction image acquired in a correction image acquisition frame Frno is stored in the dark image frame memory 803 through the multiplexer 801.

When the images are almost stored, offset correction (e.g., Frxo−Frno) is performed by the offset correction circuit 804. Subsequently, the gain correction circuit 806 performs gain correction (e.g., (Frxo−Frno)/Fg) using gain correction data Fg which is acquired and stored in the gain correction frame memory in advance. For the data transferred to the defect correction circuit 807, the image is continuously interpolated not to generate any sense of incompatibility at a dead pixel or connections between a plurality of panels of the X-ray detector 52, thus completing sensor-dependent correction processing resulted from the X-ray detector 52. In addition, the image procession circuits 808 execute general image processing such as grayscale processing, frequency processing, and emphasis processing. After that, the processed data is transferred to the display controller 32, and the image is displayed on the monitor 30.

FIGS. 15 and 16 are views showing examples of the driving mechanism of the grid 54.

A frame 901 holds the grid 54. A cam mechanism 902 for vibrating the frame 901 is connected to a rotating mechanism such as a grid driving motor (not shown).

The grid driving motor (not shown) rotates and stops at the grid moving timing shown in FIG. 13 in accordance with an instruction from the driver 62, thereby moving the grid 54 in the direction indicated by the arrow or stopping the grid 54. An elastic member 1001 for moving the grid is formed from, e.g., a spring. A mechanism 1002 for moving the grid 54 to the home position is formed from, e.g., a solenoid. A braking mechanism 1003 stops the grid 54. In the initialization operation, the solenoid mechanism 1002 is operated to move the grid to the home position indicated by the broken line, and the grid is stopped by the braking mechanism 1003. The grid 54 is moved by canceling the braking on the basis of an instruction from the driver 62. The braking mechanism 1003 stops the grid in accordance with an instruction from the driver 62 at a predetermined timing.

As described above, according to the X-ray image sensing apparatus of this embodiment, a satisfactory image can be easily and reliably obtained without any influence of vibration of the grid 54 or the like by a very simple arrangement.

(Fourth Embodiment)

In this embodiment, the internal arrangement of an X-ray room 10 is almost the same as in FIG. 7, and a description of common units will be omitted.

Reference numeral 48b denotes part of an imaging bed 48 and represents a bed for a fluoroscopic system in FIG. 17. A fluoroscopic II (Image Intensifier) 1101 is controlled by an image sensing controller 24 to transfer an acquired image to an image processor 26 and then display the image on a monitor 30 or monitor dedicated to a fluoroscopic image, like an X-ray detector 52. The X-ray detector 52 is mainly located at a position B during a fluoroscopic image acquisition period and mainly moves to a position A during a simple image acquisition period. The X-ray detector 52 is moved in accordance with an instruction from the image sensing controller 24 to the imaging bed 48. The moving operation is performed by a mechanical means (not shown) for moving the X-ray detector 52.

FIG. 18 is a timing chart including image sensing operation of the X-ray detector 52. The operation of the X-ray detector 52 of this embodiment will be described mainly with reference to FIG. 18.

FIG. 18 is almost the same as FIG. 13, and different points will be mainly explained.

Reference numeral 1201 denotes an image sensing request signal to an operator interface 22, which represents a simple X-ray imaging request state in FIG. 13 but a fluoroscopic/simple imaging request in this embodiment. Reference numeral 702 denotes an actual X-ray exposure state; 703, an imaging request signal from the image sensing controller 24 to a driver 62 on the basis of an instruction from an operator 21; 704, an imaging ready signal of the X-ray detector 52; 705, a drive signal for a grid 54; 706, a power control signal in the X-ray detector 52; 707, a driven state of the X-ray detector (especially charge read operation from a photodetector array 58); and 708, an image data transfer state or an image processing or display state. In addition, reference numeral 1202 denotes an X-ray output state for X-ray fluoroscopy; 1203, a concept of moving speed of the X-ray detector 52; and 1204, a position of the X-ray detector 52.

While no request is received from the operator 21, the X-ray detector 52 stands by at the position B of the imaging bed 48.

When a fluoroscopy request 1201 from the operator 21 is detected, fluoroscopic imaging is started (1202), and simultaneously, the X-ray detector 52 starts idling drive (707). When the operator 21 determines the object to be sensed and outputs a general imaging preparation request (1st SW: 1201), the X-ray generator 40 starts preparing for X-ray generation for general imaging and ends the preparation after a predetermined time. When the operator 21 inputs a general imaging request (2nd SW: 1201), the image sensing controller 24 starts X-ray image acquisition drive, instructs the X-ray detector 52 to prepare for imaging (703), stops fluoroscopic imaging (1202), and starts moving the X-ray detector 52 (1203 and 1204).

In this embodiment, the image sensing controller 24 as a control means performs control such that the driver 62 operates the photodetector array 58 in a steady state with a converged vibration, i.e., at a predetermined speed (uniform speed) without acceleration during an operation period related to the read of the X-ray detector 52 as a detection means.

At the start of moving, moving is started while continuously changing the acceleration not to increase the vibration. Since a time T3 until the end of imaging preparation of the X-ray detector 52 is known in advance, the X-ray detector 52 is completely moved to the general imaging position A within a time according to the time T3. However, in the driven state 707, when vibration occurs at the time of a frame Fpf immediately before the end of imaging preparation, noise is readily superposed on the image. To prevent this, immediately after the end of the frame Fpf, stop operation of the X-ray detector 52 is started, and until this time, the X-ray detector 52 is controlled to move at a constant speed without generating any acceleration.

When preparation is ended, the X-ray exposure 702 is performed. Immediately after exposure is ended, an X-ray image acquisition frame Frxo is driven to acquire an X-ray image (707). After the end of X-ray exposure 702, fluoroscopic imaging should be started as soon as possible. After the drive of the X-ray image acquisition frame Frxo is ended, correction dark image acquisition drive is started, and simultaneously, movement of the X-ray detector 52 from the position A to the position B is immediately started (1204). As in the preceding X-ray image acquisition drive, movement is started while continuously changing the acceleration not to increase the vibration. Since the time T3 until the end of imaging preparation of the X-ray detector 52 is known in advance, as in the X-ray image acquisition drive, the X-ray detector 52 is completely moved to the general imaging position B within a time according to the time T3. Contents related to the frame Fpf immediately before the end of imaging preparation are also the same as in the X-ray image acquisition drive. When movement from the position A to the position B is ended, fluoroscopic imaging is resumed, and the fluoroscopic image can be redisplayed from this time. After that, a rough image acquisition frame Frno is driven at a predetermined timing to acquire a rough image. The general image is subjected to predetermined image processing and then displayed on the monitor 30.

For the control, as in the third embodiment, a sensor (not shown) capable of detecting a vibration amount may be arranged in or near the X-ray detector 52, and a predetermined read (e.g., the X-ray image acquisition frame Frxo, dark image acquisition frame Frno, or frame Fpf immediately before the end of imaging preparation) may be started when the vibration becomes equal to or smaller than a predetermined value.

For the control, except a predicted period of vibration in the driver 62, an operation period related to the image read of the X-ray detector 52 may be set, and drive related to image acquisition may be performed during this operation period.

As described above, according to the X-ray image sensing apparatus of this embodiment, a satisfactory image can be easily and reliably obtained without any influence of vibration of the X-ray detector 52 or the like by a very simple arrangement.

(Fifth Embodiment)

In this embodiment, the internal arrangement of an X-ray room 10 is almost the same as in FIG. 7, and a description of common units will be omitted.

Reference numeral 48b denotes part of an imaging bed 48 and represents a bed for a fluoroscopic system in FIG. 17. A fluoroscopic II (Image Intensifier) 1101 is controlled by an image sensing controller 24 to transfer an acquired image to an image processor 26 and then display the image on a monitor 30 or monitor dedicated to a fluoroscopic image, like an X-ray detector 52. The X-ray detector 52 is mainly located at a position B during a fluoroscopic image acquisition period and mainly moves to a position A during a simple image acquisition period. The X-ray detector 52 is moved in accordance with an instruction from the image sensing controller 24 to the imaging bed 48. The moving operation is performed by a mechanical means (not shown) for moving the X-ray detector 52.

FIG. 19 is a timing chart including image sensing operation of the X-ray detector 52. The operation of the X-ray detector 52 of this embodiment will be described mainly with reference to FIG. 19.

FIG. 19 is almost the same as FIG. 13, and different points will be mainly explained.

Reference numeral 1201 denotes an image sensing request signal to an operator interface 22, which represents a simple X-ray imaging request state in FIG. 13 but a fluoroscopic/simple imaging request in this embodiment. Reference numeral 702 denotes an actual X-ray exposure state; 703, an imaging request signal from the image sensing controller 24 to a driver 62 on the basis of an instruction from an operator 21; 704, an imaging ready signal of the X-ray detector 52; 705, a drive signal for a grid 54; 706, a power control signal in the X-ray detector 52; 707, a driven state of the X-ray detector (especially charge read operation from a photodetector array 58); and 708, an image data transfer state or an image processing or display state. In addition, reference numeral 1202 denotes an X-ray output state for X-ray fluoroscopy; 1203, a concept of moving speed of the X-ray detector 52; and 1204, a position of the X-ray detector 52.

While no request is received from the operator 21, the X-ray detector 52 stands by at the position B of the imaging bed 48.

When a fluoroscopy request 1201 from the operator 21 is detected, fluoroscopic imaging is started (1202), and simultaneously, the X-ray detector 52 starts idling drive (707). When the operator 21 determines the object to be sensed and outputs general imaging preparation request (1st SW: 1201), the X-ray generator 40 starts preparing for X-ray generation for general imaging and ends the preparation after a predetermined time. When the operator 21 inputs a general imaging request (2nd SW: 1201), the image sensing controller 24 starts X-ray image acquisition drive, instructs the X-ray detector 52 to prepare for imaging (703), stops fluoroscopic imaging (1202), and starts moving the X-ray detector 52 (1203 and 1204).

In this embodiment, the image sensing controller 24 as a control means performs control such that the driver 62 operates the photodetector array 58 in a steady state with a converged vibration, i.e., at a predetermined acceleration during an operation period related to the read of the X-ray detector 52 as a detection means.

When a desired acceleration is obtained, the motion preferably shifts to uniformly accelerated motion. In general control, actually, the acceleration abruptly changes (arrows in 1205). Since a time T3 until the end of imaging preparation of the X-ray detector 52 is known in advance, the X-ray detector 52 is completely moved to the general imaging position A within a time according to the time T3. When the movement and frame Fpf are synchronously ended, the time from the 2nd SW to the X-ray exposure 702 can be minimized. Hence, a frame Fpf is required to be ended at the time of predetermined deceleration (negative acceleration). In the driven state 707, when vibration occurs at the time of the frame Fpf immediately before the end of imaging preparation, noise is readily superposed on the image. To prevent this, the frame Fpf is acquired at a timing when the vibration due to the abrupt change in acceleration has converged, and the X-ray detector 52 is stopped immediately after the end of the frame Fpf.

When preparation is ended, the X-ray exposure 702 is performed. After the end of X-ray exposure 702, fluoroscopic imaging should be started as soon as possible. Hence, movement of the X-ray detector 52 from the position A to the position B is started immediately after the end of exposure (1204). Simultaneously, the X-ray image acquisition frame Frxo is driven at the time of uniform acceleration (or uniformly accelerated motion) at the timing when the vibration due to a change in acceleration converges, thereby acquiring an X-ray image. After the end of the X-ray image acquisition frame Frxo, correction dark image acquisition drive is started. Since the time T3 until the end of imaging preparation of the X-ray detector 52 is known in advance, as in the X-ray image acquisition drive, the X-ray detector 52 is completely moved to the general imaging position B within a time according to the time T3. Contents related to the frame Fpf immediately before the end of imaging preparation are also the same as in the X-ray image acquisition drive. When movement from the position A to the position B is ended, fluoroscopic imaging is resumed, and the fluoroscopic image can be redisplayed from this time. After that, a dark image acquisition frame Frno is driven at a predetermined timing to acquire a dark image. The general image is subjected to predetermined image processing and then displayed on the monitor 30.

For the control, as in the third embodiment, a sensor (not shown) capable of detecting a vibration amount may be arranged in or near the X-ray detector 52, and a predetermined read (e.g., the X-ray image acquisition frame Frxo, dark image acquisition frame Frno, or frame Fpf immediately before the end of imaging preparation) may be started when the vibration becomes equal to or smaller than a predetermined value.

For the control, except a predicted period of vibration in the driver 62, an operation period related to the image read of the X-ray detector 52 may be set, and drive related to image acquisition may be performed during this operation period.

As described above, according to the X-ray image sensing apparatus of this embodiment, a satisfactory image can be easily and reliably obtained without any influence of vibration of the X-ray detector 52 or the like by a very simple arrangement.

Three embodiments, the third to fifth embodiments, have been described above. The present invention is applied to a cooling fan or any other potential vibration source.

The present invention also incorporates a case wherein to operate various devices to implement the functions of the above-described embodiments, software program codes for implementing the functions of the embodiments are supplied to a computer in an apparatus or system connected to the devices, and the devices are operated in accordance with a program stored in the computer (or CPU or MPU) of the system or apparatus.

In this case, the software program codes themselves implement the functions of the above-described embodiments, and the program codes themselves and a means for supplying the program codes to the computer, e.g., a storage medium which stores such program codes constitute the present invention. As the storage medium for storing such program codes, for example, a floppy disk, hard disk, optical disk, magnetooptical disk, CD-ROM, magnetic tape, nonvolatile memory card, ROM, or the like can be used.

The functions of the above-described embodiments are implemented when the supplied program codes are executed by the computer. In addition, even when the functions of the above-described embodiments are cooperatively implemented by an operating system (OS) running on the computer or another application software, the program codes are included in the embodiments of the present invention.

The functions of the above-described embodiments are also implemented when the supplied program codes are stored in the memory of a function expansion board inserted into the computer or a function expansion unit connected to the computer, and the CPU of the function expansion board or function expansion unit performs part or all of actual processing on the basis of the instructions of the program codes.

As has been described above, according to the third to fifth embodiments, a radiation image sensing apparatus (image sensing apparatus) and image sensing method which can easily and reliably obtain a satisfactory image without any influence of vibration or a grid or X-ray detection means by a very simple arrangement can be provided.

The present invention is not limited to the above embodiments and various changes and modifications can be made within the spirit and scope of the present invention. Therefore, to apprise the public of the scope of the present invention, the following claims are made.

Claims

1. An imaging apparatus which has a movable element related to imaging and an image sensing element, and has a function of sensing an image of an object with the image sensing element and reading as an image signal a signal generated by the image sensing element, comprising:

a radiation generation device adapted to emit radiation;

an image sensing element which converts the radiation to an electrical signal;

a control unit arranged to stop movement of the element related to imaging, and, after stopping the movement a vibration of the element has become smaller than a predetermined level after stopping movement control for the element, starting to start reading of a signal generated by the image sensing element, and

an imaging control device adapted to control said image sensing element to be in at least one of a state of sweeping out an electrical charge and a state of accumulating an electrical charge,

wherein said imaging control device controls said image sensing element to bring said image sensing element into a second state in which the sweeping out operation is repeated with a second time interval after said image sensing element has been brought into a first state in which the sweeping out operation is repeated with a first time interval.

2. The apparatus according to claim 1, wherein the element related to imaging is a grid arranged between the object and the image sensing element.

3. The apparatus according to claim 1, wherein said apparatus further comprises an irradiation detection unit arranged to detect irradiation for the object, and said control unit controls the stopping of movement of the elementrelated to imaging on the basis of a detection result from said irradiation detection unit.

4. The apparatus according to claim 1, wherein after stopping movement of a grid, said control unit starts reading the signal from the image sensing element after an elapse of a predetermined time.

5. The apparatus according to claim 4 1, wherein said control unit determines in advance the predetermined time on the basis of at least one of an irradiation time for the object and a moving speed of the element related to imaging.

6. The apparatus according to claim 1, wherein said apparatus further comprises a vibration detection unit arranged to detect a vibration state of the image sensing element due to movement of the element related to imaging, and said control unit controls a start of reading an accumulated signal from the image sensing element on the basis of a detection result from said vibration detection unit.

7. The apparatus according to claim 1, wherein irradiation for the object includes radiation irradiation.

8. An imaging apparatus which has a movable element related to imaging and an image sensing element, and has a function of sensing an image of an object with the image sensing element and reading as an image signal a signal generated by the image sensing element, comprising:

drive unit arranged to move the element related to imaging by the image sensing element; and

control unit arranged to control said drive unit to operate the element related to imaging at a predetermined speed without any acceleration during an operation period related to reading a signal from the image sensing element.

9. The apparatus according to claim 8, wherein the element related to imaging is a grid inserted between the object and the image sensing element.

10. The apparatus according to claim 8, wherein irradiation for the object includes radiation irradiation.

11. The apparatus according to claim 10, wherein the radiation comprises X-rays.

12. An imaging apparatus which has a movable element related to imaging and an image sensing element, and has a function of sensing an image of an object with the image sensing element and reading as an image signal a signal generated by the image sensing element, comprising:

drive unit arranged to move the element related to imaging; and

control unit arranged to control said drive unit to operate the element related to imaging at a uniform acceleration during an operation period related to reading a signal from the image sensing element.

13. The apparatus according to claim 12, wherein the element related to imaging is a grid inserted between the object and the image sensing element.

14. The apparatus according to claim 12, wherein irradiation for the object includes radiation irradiation.

15. The apparatus according to claim 14, wherein the radiation comprises X-rays.

16. An imaging apparatus which has a movable element related to imaging and an image sensing element, and has a function of sensing an image of an object with the image sensing element and reading as an image signal a signal generated by the image sensing element, comprising:

drive unit arranged to move the element related to imaging; and

control unit arranged to control execution of a drive operation related to image acquisition upon determining that a value of a vibration is not more than a predetermined value during an operation period related to an image read froth the image sensing element.

17. The apparatus according to claim 16, wherein the element related to imaging is a grid inserted between the object and the image sensing element.

18. The apparatus according to claim 16, wherein irradiation for the object includes radiation irradiation.

19. The apparatus according to claim 18, wherein the radiation comprises X-rays.

20. An imaging apparatus having a function of sensing an image of an object with an image sensing element and reading as an image signal a signal generated by the image sensing element, comprising:

drive unit arranged to move the image sensing element; and

control unit arranged to stop movement of the image sensing element by said drive unit, and after stopping the movement, starting reading of an accumulated signal from the image sensing element.

21. The apparatus according to claim 20, wherein after stopping movement of the image sensing element, said control unit starts reading the signal from the image sensing element after an elapse of a predetermined time.

22. The apparatus according to claim 20, wherein said apparatus further comprises vibration detection unit arranged to detect a vibration state of the image sensing element, and

said control unit controls a start of reading of the signal from the image sensing element on the basis of a detection result from said vibration detection unit.

23. The apparatus according to claim 20, wherein irradiation for the object includes radiation irradiation.

24. An imaging apparatus having a function of sensing an image of an object with an image sensing element and reading as an image signal a signal generated by the image sensing element, comprising:

drive unit arranged to move the image sensing element; and

control unit arranged to control said drive unit to operate the image sensing element at a predetermined speed without any acceleration during an operation period related to reading a signal from the image sensing element.

25. The apparatus according to claim 24, wherein irradiation for the object includes radiation irradiation.

26. The apparatus according to claim 25, wherein the radiation comprises X-rays.

27. An imaging apparatus having a function of sensing an image of an object with an image sensing element and reading as an image signal a signal generated by the image sensing element, comprising:

drive unit arranged to move the image sensing element; and

control unit arranged to control said drive unit to operate the image sensing element at a uniform acceleration during an operation period related to reading a signal from the image sensing element.

28. The apparatus according to claim 27, wherein irradiation for the object includes radiation irradiation.

29. The apparatus according to claim 28, wherein the radiation comprises X-rays.

30. An imaging apparatus having a function of sensing an image of an object with an image sensing element and reading as an image signal a signal generated by the image sensing element, comprising:

drive unit arranged to move the image sensing element; and

control unit arranged to control execution of a drive operation related to image acquisition upon determining that a value of a vibration is not more than a predetermined value during an operation period related to an image read from the image sensing element.

31. The apparatus according to claim 30, wherein irradiation for the object includes radiation irradiation.

32. The apparatus according to claim 31, wherein the radiation comprises X-rays.

33. An imaging method of sensing an image of an object with an image sensing element and reading a signal generated by the image sensing element while moving a movable element related to imaging, comprising:

irradiating the image sensing element with radiation emitted from a radiation generation device;

converting the radiation to an electrical signal;

stopping movement of the element related to imaging, and, after stopping the movement a vibration of the element has become smaller than a predetermined level after stopping movement control for the element, starting reading of a signal from the image sensing element, and

controlling said image sensing element to be in at least one of a state of sweeping out an electrical charge and a state of accumulating an electrical charge,

wherein said image sensing element is brought into a second state in which the sweeping out operation is repeated with a second time interval after said image sensing element has been brought into a first state in which the sweeping out operation is repeated with a first time interval.

34. An imaging method of sensing an image of an object with an image sensing element and reading a signal generated by the image sensing element while moving a movable element related to imaging, comprising:

in moving the element related to imaging at the time of image sensing by the image sensing element, controlling operation of the element related to imaging at a predetermined speed without any acceleration during an operation period related to reading of a signal from the image sensing element.

35. An imaging method of sensing an image of an object with an image sensing element and reading a signal generated by the image sensing element while moving a movable element related to imaging, comprising:

in moving the element related to imaging at the time of image sensing by the image sensing element, controlling operation of the element related to imaging at a uniform acceleration during an operation period related to reading a signal from the image sensing element.

36. An imaging method of sensing an image of an object with an image sensing element and reading a signal generated by the image sensing element while moving a movable element related to imaging, comprising:

in moving the element related to imaging at the time of image sensing by the image sensing element, controlling execution of a drive related to image acquisition upon determining that a value of a vibration of the image sensing element is not more than a predetermined value during an operation period related to an image read from the image sensing element.

37. An imaging method of sensing an image of an object with a movable image sensing element and reading a signal generated by the image sensing element, comprising:

stopping movement of the image sensing element, and after stopping the movement, starting reading of a signal from the image sensing element.

38. An imaging method of sensing an image of an object with a movable image sensing element and reading a signal generated by the image sensing element, comprising:

controlling operation of the image sensing element at a predetermined speed without any acceleration during an operation period related to reading a signal from the image sensing element.

39. An imaging method of sensing an image of an object with a movable image sensing element and reading a signal generated by the image sensing element, comprising:

controlling operation of the image sensing element at a uniform acceleration during an operation period related to reading a signal from the image sensing element.

40. An imaging method of sensing an image of an object with a movable image sensing element and reading a signal generated by the image sensing element, comprising:

controlling execution of a drive operation related to image acquisition upon determining that a value of a vibration of the image sensing element is not more than a predetermined value during an operation period related to an image read from the image sensing element.

41. A computer-readable storage medium wherein said storage medium stores a processing program for executing said imaging method of claim 33.

42. A computer-readable storage medium wherein said storage medium stores a processing program for executing said imaging method of claim 34.

43. A computer-readable storage medium wherein said storage medium stores a processing program for executing said imaging method of claim 35.

44. A computer-readable storage medium wherein said storage medium stores a processing program for executing said imaging method of claim 36.

45. A computer-readable storage medium wherein said storage medium stores a processing program for executing said imaging method of claim 37.

46. A computer-readable storage medium wherein said storage medium stores a processing program for executing said imaging method of claim 38.

47. A computer-readable storage medium wherein said storage medium stores a processing program for executing said imaging method of claim 39.

48. A computer-readable storage medium wherein said storage medium stores a processing program for executing said imaging method of claim 40.