JP6320155B2 - Image processing apparatus, radiation imaging apparatus, control method therefor, radiation imaging system, and program - Google Patents

Description

  The present invention relates to an image processing apparatus, a radiation imaging apparatus, a control method thereof, a radiation imaging system, and a program.

  Conventionally, a subject is irradiated with radiation from a radiation source, the radiation image that is the intensity distribution of the radiation that has passed through the subject is digitized, and the digitized radiation image is subjected to necessary image processing to provide a clearer radiation image. A digital radiography apparatus that generates a radiography and a radiography system using the apparatus have been commercialized.

  In recent years, the radiation imaging device itself can detect the start of radiation irradiation from the radiation generation device, eliminating the need to connect the radiation imaging device and the radiation generation device, and further improving the ease of installation and handling. An imaging device and a radiation imaging system are also realized.

  In Patent Document 1 and Patent Document 2, each scanning line of the radiation imaging apparatus is sequentially selected, irradiation is waited while switching between the on state and the off state, and the start of radiation irradiation is detected when a change in the current flowing in the apparatus is detected. A method of performing detection is disclosed. According to this method, in the pixel corresponding to the scanning line in which the radiation imaging apparatus detects the start of irradiation after the start of radiation irradiation and stops scanning, a part of the charge generated by the radiation irradiation flows out. In particular, a linear or wedge-shaped defect may occur on the radiographic image.

  Furthermore, gain correction processing is generally performed on the acquired radiographic image during processing from imaging to image acquisition. This is because the gain (sensitivity) of each pixel is caused by unevenness due to the film formation process of the radiation detection sensor, the existence of pixels with different characteristics that occur specifically, aging and burn-in that occur as they are used. This is for correcting the variation. In the gain correction process, a radiation image (hereinafter referred to as a gain image) obtained by uniformly irradiating the entire surface of the detection sensor with radiation is used when the radiation imaging apparatus is installed or periodically after installation. For example, the output value of a radiographic image obtained by irradiating a subject with radiation is divided by the output value of each corresponding pixel of the gain image.

JP 2011-247605 A JP2011-249891A

  However, when a gain image is captured by a method of detecting the start of radiation irradiation from a change in internal current, a linear or wedge-shaped defect is similarly generated in the gain image. When a defect in the gain image is corrected by some image processing, the pixel in which the defect has occurred cannot correctly represent the original gain, and thus there is a possibility that the gain correction cannot be performed correctly.

  In view of the above problems, an object of the present invention is to generate a sensitivity-correcting image without defects even when imaging is performed by detecting radiation irradiation based on a current change in the radiation imaging apparatus. .

An image processing apparatus according to the present invention that achieves the above object is as follows.
Photographed without placing an object, an acquisition unit that acquires information indicating a plurality of radiographic images which the position of the defect is different, the position of the defect in the radiation image,
Generating means for generating a sensitivity correction image not including the defect based on the plurality of radiation images and information indicating the position of the defect;
It is characterized by providing.

  ADVANTAGE OF THE INVENTION According to this invention, even when it is a case where it is a case where it image | photographs by detecting radiation irradiation based on the electric current change inside a radiography apparatus, the image for sensitivity correction without a defect can be produced | generated.

It is a figure which shows an example of a structure of the radiography system in this invention. It is a figure which shows an example of a structure of the radiography apparatus in 1st Embodiment of this invention. It is a figure which shows an example of a structure of the radiation sensor part in this invention. It is a figure which shows an example of the scanning order of the radiation sensor part in this invention. It is a figure which shows an example of the scanning order of the radiation sensor part in this invention. It is a figure which shows an example of the scanning order of the radiation sensor part in this invention. It is a figure which shows an example of a structure of the detection part in this invention. It is a figure which shows an example of the image division | segmentation method in this invention. It is a figure which shows an example of the image division | segmentation method in this invention. It is a figure which shows an example of a structure of the image processing apparatus in 1st Embodiment of this invention. It is a flowchart which shows the production | generation procedure of the gain image in this invention. It is a figure which shows the mode of the production | generation of the gain image in this invention. It is a desirable image display example at the time of the production | generation of the gain image in this invention. It is a figure which shows an example of a structure of the radiography apparatus in 2nd Embodiment of this invention. It is a figure which shows an example of a structure of the gain image generation part in 2nd Embodiment of this invention. It is a figure which shows an example of a structure of the image processing apparatus in 2nd Embodiment of this invention. It is a figure which shows an example of a structure of the radiography apparatus in 3rd Embodiment of this invention. It is a flowchart which shows the determination operation | movement procedure regarding the gain image in 3rd Embodiment of this invention. It is a figure which shows an example of a structure of the radiography apparatus in 4th Embodiment of this invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings.

(First embodiment)
First, the first embodiment will be described. In the present embodiment, an example in which a defect-free sensitivity correction image (gain image) is generated using two defective images and positional information of the defects will be described in detail.

<1. Configuration of radiation imaging system>
FIG. 1 is a diagram showing an example of the configuration of a radiation imaging system 1 according to the present invention. The radiation imaging system 1 includes a radiation imaging apparatus 101, a radiation tube 102, a radiation generation apparatus 103, a control apparatus 104, and an image processing apparatus 105.

  The radiation imaging apparatus 101 has a built-in wireless transmission / reception device and can wirelessly communicate with an external device. The radiation tube 102 is installed relative to the radiation imaging apparatus 101. When taking a radiographic image of a subject, the subject is placed between the radiation tube 102 and the radiation imaging apparatus 101.

  The control device 104 controls the radiation generation device 103. The image processing apparatus 105 has a built-in wireless transmission / reception device and can perform wireless communication with an external device. As the image processing apparatus 105, a personal computer is generally used. The image processing apparatus 105 performs an operation instruction to the radiation imaging apparatus 101 and obtains a state of the radiation imaging apparatus 101. Further, the image processing apparatus 105 performs image processing, image storage, image display, and the like. The radiation imaging apparatus 101 and the image processing apparatus 105 exchange information and transmit / receive data via the wireless communication interface of the communication unit. Further, communication between the radiation imaging apparatus 101 and the image processing apparatus 105 may be performed via a wireless access point or the like, or may be performed by wired connection using a physical cable.

<2. Configuration of radiation imaging apparatus>
FIG. 2 is a diagram illustrating an example of an internal configuration of the radiation imaging apparatus 101. The radiation imaging apparatus 101 includes a radiation sensor unit 201, an image dividing unit 202, an image memory 203, an offset correction unit 204, a communication unit 205, a power supply circuit 206, and a battery 207 for operating wirelessly. Including.

  The image data output from the radiation sensor unit 201 is divided into a plurality of reduced images by the image dividing unit 202 and temporarily stored in the image memory 203. Since the image data stores a plurality of reduced radiation images acquired by irradiating radiation and a plurality of offset reduced images acquired without irradiating radiation, the image memory 203 has a capacity to hold at least these simultaneously. Prepare. As the image memory 203, a volatile memory having a high access speed such as a DRAM (Dynamic Random Access Memory) is often used, but a non-volatile memory such as a flash memory may be used.

  The offset correction unit 204 reads the radiation reduced image and the offset reduced image from the image memory 203, and performs offset correction processing by performing subtraction between the corresponding images. Further, the radiation sensor unit 201 holds information (defect correction information) for correcting defects generated in an image by the imaging method performed in the present embodiment. The defect correction information can also be held in the image memory 203. The communication unit 205 transmits the defect correction information and the divided image to the image processing apparatus 105. The communication unit 205 includes a wireless communication interface, a wired communication interface, and a switching circuit for these interfaces. Moreover, the cable connection part for wired communication is provided.

<3. Configuration of radiation sensor section>
FIG. 3 shows an outline of the radiation sensor unit 201 inside the radiation imaging apparatus 101. For simplification, only a circuit for pixels of 2 rows × 2 columns is shown, but in recent years, a sensor having pixels of several thousand rows × thousand columns is generally used. Note that the present invention does not limit the number of rows, the number of columns, and the number of pixels. The radiation sensor unit 201 includes a radiation sensor control unit 302, a scanning unit 303, a TFT (Thin Film Transistor) 304, a detection unit 305, a bias line 306, a photoelectric conversion element 307, an image generation unit 308, and a bias. And a power supply 309.

  Upon receiving an instruction to start imaging preparation from the image processing apparatus 105, the radiation imaging apparatus 101 operates to prepare for the operation of the power supply circuit 206 and the like, and then detects radiation irradiation (referred to as a radiation irradiation detection state). To transit to the shooting state. Hereinafter, the radiation irradiation detection state will be described.

  The radiation sensor control unit 302 drives the scanning unit 303 to perform scanning that sequentially turns on the TFTs 304 for each row according to a predetermined condition. That is, the sensors are sequentially selected in the row direction to switch the on state / off state. There is no limitation on the scanning order, the number of rows in which TFTs are simultaneously turned on, and the like. Here, FIG. 4, FIG. 5, and FIG. 6 show an example of the scanning order of the radiation sensor unit having n rows of scanning lines L1 to Ln.

  As shown in FIG. 4, the TFTs may be turned on one by one from the top row of the radiation sensor unit 201 and sequentially scanned. Alternatively, as shown in FIG. . Further, as shown in FIG. 6, scanning may be performed while skipping a predetermined number of rows instead of sequentially. Furthermore, these may be combined. Scanning continues until radiation irradiation is detected. When all rows are scanned, scanning is performed again from the first scanned row.

  The detection unit 305 detects a current flowing in the bias line 306 connected to the bias power supply 309 and converts it into a digital value while the scanning unit 303 is driven. The image generation unit 308 reads out electric charges and generates a radiation image in synchronization with an operation in which the scanning unit 303 performs scanning while sequentially turning on the TFTs in each row. The bias power supply 309 supplies a bias voltage to the photoelectric conversion element 307.

<4. Configuration of detection unit>
FIG. 7 is a diagram illustrating an example of the configuration of the detection unit 305. The detection unit 305 includes a current-voltage conversion circuit 701, an amplifier 702, an AD converter 703, a signal processing circuit 704, a comparator 705, and a storage circuit 706.

  While the scanning unit 303 is being driven, the detection unit 305 converts the current flowing through the bias line 306 connected to the bias power supply 309 into a current-voltage conversion circuit 701, an amplifier 702, an AD converter 703, and a signal processing circuit. A digital value is converted through 704. The comparator 705 compares the digital value with a predetermined threshold value, and outputs a signal indicating the comparison result to the radiation sensor control unit 302 or the like as a radiation irradiation detection signal. Here, if the digital value exceeds a predetermined threshold, the radiation sensor control unit 302 can determine that there is a change in the current flowing through the bias line 306 and that radiation irradiation has been detected. In addition, the detection unit 305 sequentially stores digital values in the storage circuit 706. The state in which these operations are performed corresponds to the radiation irradiation detection state.

  Here, the sampling frequency of the AD converter 703 is arbitrary, and sampling may be performed a plurality of times at the timing when the TFT of a certain scanning line is turned on. For data processing, it is desirable to use one digital value. In addition, in a state where a certain scanning line is selected, a correlated double sampling that obtains a digital value when the TFT 304 is turned on and a digital value when the TFT 304 is turned off and calculates a difference between them. It is desirable to do. Thereby, the tolerance to external noise can be increased. Since the digital value is sequentially updated in synchronization with scanning, the storage circuit 706 has a capacity capable of holding at least one digital value for all rows or the number of scans by sequentially overwriting and updating the digital values. desirable.

  When radiation is irradiated from the radiation tube 102, electric charges are generated in the photoelectric conversion element 307 due to light emission from a scintillator layer (not shown) and flow out to the bias line 306. As a result, the current flowing through the bias line 306 changes. The detection unit 305 detects the change in the current through the above-described circuits (current-voltage conversion circuit 701, amplifier 702, AD converter 703, and signal processing circuit 704), and instructs the radiation sensor control unit to stop the above-described scanning. It outputs to 302.

  Thereby, the radiation sensor unit 201 transitions to a charge accumulation state caused by radiation irradiation. When the scanning is stopped, the storage circuit 706 stops updating the digital value and holds the digital value, and the radiation sensor control unit 302 sets the scanning line number (scanning line position information) for specifying the scanning line for which the scanning is stopped. Store in the illustrated register. Note that it is not always necessary to use the scanning line number (row number) as long as the position where scanning is stopped can be specified.

  In the present embodiment, a detection method in which a change in the current flowing through the bias line 306 is used for detection of radiation irradiation is shown. However, the current that flows inside the radiation imaging apparatus 101 whose value changes due to radiation irradiation is used, and the position of the defect caused by the radiation irradiation detection method that occurs in the radiation image stops the above scanning. The detection method is not limited to this as long as the detection method is determined from the determined position. Further, it is not always necessary to use a current flowing through the bias line 306.

  When a predetermined time elapses after the transition to the charge accumulation state, the radiation sensor unit 201 performs an image reading operation. In the image reading operation, the scanning unit 303 performs scanning while sequentially turning on the TFTs in each row, and in synchronization with this, the image generation unit 308 reads out the charges and generates a radiation image. Next, charges are accumulated without irradiation, and an image reading operation is performed again to generate an offset image.

  8 and 9 show how the full image is divided by the image dividing unit 202 in the radiation imaging apparatus 101. FIG. A case where a full image 801 having M rows × N columns of pixels output from the radiation sensor unit 201 is input to the image dividing unit 202 is shown. The image dividing unit 202 divides the full image 801 into a plurality of reduced images based on a condition determined by the pixel position. In the example of FIG. 8, 4 pixels of 2 rows × 2 columns are used as a unit for the full image 801, and reduced image 1 (reduced image 802) and reduced image 2 (reduced image) of M / 2 rows × N / 2 columns depending on the pixel position. An image 803), a reduced image 3 (reduced image 804), and a reduced image 4 (reduced image 805) are divided into four reduced images. These reduced images are stored in the image memory 203.

  In the example of FIG. 9, 16 pixels of 4 rows × 4 columns are used as a unit with respect to the full image 901, and reduced image 1 (reduced image 902) and reduced image 2 (reduced image) of M rows × N / 4 columns depending on the pixel position. 903), the reduced image 3 (reduced image 904), and the reduced image 4 (reduced image 905) are divided into four reduced images.

  Note that both the radiation image and the offset image are divided into reduced images having the same number of pixels and the same number based on the same conditions, and are stored in the respective storage addresses of the image memory 203. The number of each reduced image indicates the order of transmission from the radiation imaging apparatus 101 to the image processing apparatus 105.

  After all of the radiation reduced image and the offset reduced image are stored in the image memory 203, the offset correction unit 204 performs offset correction and passes the image to the communication unit 205. The offset correction unit 204 first reads out the radiation reduced image 1 and the offset reduced image 1 from the image memory 203, and performs offset correction by subtracting the offset reduced image 1 from the radiation reduced image 1 at the same pixel positions. Subsequently, offset correction is similarly performed on the radiation reduced image 2 and the offset reduced image 2, the radiation reduced image 3 and the offset reduced image 3, and the radiation reduced image 4 and the offset reduced image 4.

  The communication unit 205 sequentially transmits the offset-corrected reduced images to the image processing device 105. Further, defect correction information is transmitted to the image processing apparatus 105 together with the image. In the present embodiment, the defect correction information is a digital value and scanning line position information held in the storage circuit 706.

<5. Configuration of Image Processing Device>
FIG. 10 is a diagram illustrating an example of an internal configuration of the image processing apparatus 105. The image processing apparatus 105 includes a communication unit 1001, a divided image composition unit 1002, a gain image generation unit 1003, a defect correction information preprocessing unit 1004, an image processing unit 1005, a display device 1006, a storage device 1007, A network interface 1008 and an input interface 1009 are provided.

  The communication unit 1001 receives defect correction information such as digital values and scanning line position information and image data, and exchanges operation instructions and operation states with the radiation imaging apparatus 101. The divided image synthesizing unit 1002 performs necessary enlargement processing such as square processing on the offset-corrected reduced image 1 received from the radiation imaging apparatus 101 to generate an image for primary preview. Next, when receiving the reduced image 2 subjected to the offset correction, the divided image synthesizing unit 1002 performs necessary enlargement processing such as square using the reduced image 1 and the reduced image 2 subjected to the offset correction, and the two images having different definition levels. An image for the next preview is generated.

  Subsequently, when receiving the reduced image 3 and the reduced image 4 subjected to the offset correction, the divided image combining unit 1002 reconstructs the full image before the division using all the reduced images subjected to the offset correction. As described above, the image processing apparatus 105 reconstructs a plurality of types of preview images with different definition levels and images before division based on the plurality of reduced images received from the radiation imaging apparatus 101.

  The gain image generation unit 1003 generates a gain image used for gain correction processing. The defect correction information preprocessing unit 1004 performs preprocessing such as filtering on the defect correction information. An image processing unit 1005 performs correction processing such as offset correction, correction using defect correction information subjected to preprocessing, gain correction using a gain image, and defective pixel correction on a preview image and a full image, sharpening, Performs image processing such as gradation processing. The display device 1006 displays a preview image and a full image that have been subjected to image processing. The storage device 1007 stores images. The image is transferred from the storage device 1007 to the hospital server or the like from the network interface 1008 via a hospital network (not shown). The input interface 1009 accepts input of various information.

  Here, the image used by the gain image generation unit 1003 to generate the gain image is uniformly distributed on the entire surface of the radiation sensor unit 201 without placing anything between the radiation imaging apparatus 101 and the radiation tube 102. The image is taken by adjusting the positional relationship and the aperture between the radiation imaging apparatus 101 and the radiation tube 102 so that they are irradiated. Although the radiation dose to be irradiated is arbitrary, it is desirable that the radiation dose is within a range in which the linearity between the radiation dose and the output value of the radiation sensor unit 201 is maintained.

  For the radiation imaging apparatus 101, capturing a radiographic image of a subject is exactly the same as capturing a gain image. In this embodiment, the image used for generating the gain image is also transmitted sequentially as a plurality of reduced images obtained by dividing the full image, like the radiographic image of the subject. However, when generating the gain image, the image is not divided into reduced images. You may comprise.

<6. Processing performed in the radiation imaging system>
FIG. 11 is a flowchart of a gain image generation procedure in the present embodiment. FIG. 12 is a diagram showing how gain images are generated. In S1101, variables n (n = 2, 3,...) And m (m = 0, 1, 2,...) Are initialized (n = 2 and m = 0). In step S1102, the first image is captured by the radiation imaging apparatus 101, the image processing apparatus 105 acquires the image, and the divided image composition unit 1002 reconstructs the image from a plurality of reduced images to form a full image 1201 as illustrated in FIG. get. In addition, the defect position L1 and defect width W1 of the first image are acquired from the defect correction information (defect position information and defect width information) of the first image.

  In S1103, the second image is captured by the radiation imaging apparatus 101, and the divided image combining unit 1002 acquires the second full image 1202, and sets the defect position L2 and the defect width W2 of the second image. get.

  In step S1104, it is determined whether the distance between the defect position L1 and the defect position L2 on the image is sufficiently larger than the defect width W1 and the defect width W2. That is, it is determined whether or not the following expression (1) is satisfied. However, L >> W1, W2.

  If the expression (1) is satisfied, the process proceeds to S1105. On the other hand, when Expression (1) is not satisfied, the process proceeds to S1106. In step S <b> 1105, the divided image combining unit 1002 generates a combined image 1203 having no defect from the first and second images. As shown in FIG. 12, for example, the composite image is generated by replacing the portion of width 2 × W1 and W1 from the defect position L1 of the first image 1201 with the same width at the same position of the second image 1202. By replacing with

  In S1106, 1 is added to n, and the process returns to S1103 to capture the third image. The same process is repeated until an image is captured until Expression (1) is satisfied. Therefore, the formula (1) is generalized to the following formula (2). However, L >> W1, Wn.

  In S1107, 1 is added to m. In step S1108, it is determined whether m = 4. In the present embodiment, four composite images are generated. If the number is less than 4, the process returns to S1102, and the procedure of S1102 to S1106 is repeated.

  In step S1109, after generating four defect-free composite images, the composite images are averaged to reduce noise. This is obtained by outputting the average value of the four pixel values for each pixel position of the four composite images. This completes the gain image generation process.

  The gain image generated here is held in the image processing unit 1005 and used for gain correction every time a radiographic image of the subject is captured. Note that the gain image may be held in the storage device 1007. Although FIG. 11 shows a flow for performing averaging after generating a plurality of composite images (four in this example), averaging may be executed each time a composite image is generated. In this case, the memory area for holding the composite image can be reduced. In addition, noise can be reduced by averaging, but the number of composite images to be averaged is arbitrary according to the requirements of the radiation imaging system, and may not be averaged.

  In the present embodiment, L is determined from W1 and Wn acquired from the defect correction information. However, L can be determined in advance from conditions such as irradiation dose. In that case, it is necessary to determine with sufficient margin. The generation of the gain image is performed when the radiation imaging apparatus 101 is installed, but may be performed periodically, for example, every year.

  The series of operations for generating the gain image may be instructed to the user by the GUI (Graphical User Interface) displayed on the display device 1006 included in the image processing apparatus 105, for example. At that time, as shown in FIGS. 13A and 13B, the image processing apparatus 105 has information 1301 indicating how many composite images have been successfully generated, and needs to perform the next shooting. Information 1302 indicating, information 1303 indicating that the generation of the gain image has ended may be displayed so that the user can understand.

  As described above, according to the present embodiment, a defect-free sensitivity correction image (gain image) can be obtained even when imaging is performed by detecting radiation irradiation based on a current change in the radiation imaging apparatus. Can be generated.

(Second Embodiment)
Next, a second embodiment will be described.

<1. Configuration of radiation imaging apparatus>
FIG. 14 is a diagram illustrating an example of an internal configuration of the radiation imaging apparatus 101 according to the second embodiment. The radiation imaging apparatus 101 includes a radiation sensor unit 201, an image dividing unit 202, a communication unit 205, a power supply circuit 206, a battery 207, a gain image generation unit 1401, an image memory 1402, and an offset correction unit 1403. It has.

  In the first embodiment, the gain image is generated inside the image processing apparatus 105. In contrast, in the second embodiment, a gain image is generated inside the radiation imaging apparatus 101. For this reason, the radiation imaging apparatus 101 includes a gain image generation unit 1401. Further, when the gain image is generated, the image is stored in the image memory 1402 as a full image without using the image dividing unit 202. Therefore, the image memory 1402 needs to temporarily hold a plurality of radiation reduced images, a plurality of offset reduced images, and a radiation full image and an offset full image. For this purpose, an image memory area of a size that can hold all the images at the same time may be prepared. However, since it is not necessary to hold the reduced image and the full image at the same time, the same image memory area may be used. good. The offset correction unit 1403 can execute offset correction between reduced images and offset correction between full images.

<2. Configuration of Gain Image Generation Unit>
FIG. 15 shows an example of the internal configuration of the gain image generation unit 1401. The gain image generation unit 1401 includes a determination unit 1501, a composition image buffer 1502, a composition unit 1503, an averaging unit 1504, and a gain image buffer 1505.

  Generation of the gain image is started, and first, the determination unit 1501 acquires the defect position L1 and the defect width W1 of the first image from the defect correction information of the first image. At the same time, the first image is transferred from the offset correction unit 1403 to the composition image buffer 1502 and stored in the first image area. Next, the determination unit 1501 acquires the defect position L2 and the defect width W2 of the second image from the defect correction information of the second image.

  The determination unit 1501 determines whether the defect position L1 and the defect position L2 satisfy Expression (2). That is, it is determined whether or not a sensitivity correction image (gain image) can be generated. When the expression (2) is satisfied, the second image is stored in the second image area of the composition image buffer 1502. On the other hand, when Expression (2) is not satisfied, the determination unit 1501 notifies the image processing apparatus 105 that the next shooting is necessary via the communication unit 205 and causes the next shooting to be performed.

  When the expression (2) is satisfied, the composition unit 1503 reads two images from the composition image buffer 1502 and generates a composite image having no defect. The combining process is the same as that in the first embodiment. The synthesized image is sent to the averaging unit 1504. The second to fourth composite images are generated in the same manner. The averaging unit 1504 stores the first composite image in the gain image buffer 1505 as it is. In the case of the second to fourth sheets, the image is read from the gain image buffer 1505, averaged with the sent composite image, and written back to the gain image buffer 1505. When the averaging process is completed for the four composite images, the determination unit 1501 notifies the image processing apparatus 105 via the communication unit 205 that the gain image generation has been completed. Finally, the gain image is transmitted from the gain image buffer 1505 to the image processing apparatus 105 via the communication unit 205.

<3. Configuration of Image Processing Device>
FIG. 16 is an example of an internal configuration of the image processing apparatus 105 according to the second embodiment. Unlike the first embodiment, the image processing apparatus 105 according to the second embodiment does not include the gain image generation unit 1003, but the other configurations are the same as those described with reference to FIG. The communication unit 1001 causes the image processing unit 1005 to hold the received gain image. It may be held in the storage device 1007. The gain correction is the same as that in the first embodiment. The same applies to the notification by the display device 1006 to the user.

  The composition image buffer 1502 and the gain image buffer 1505 in the gain image generation unit 1401 may use physically independent memories, or may have different address areas on the same memory as the image memory 1402 physically. It may be used.

  As described above, according to the present embodiment, a defect-free sensitivity correction image (gain image) can be obtained even when imaging is performed by detecting radiation irradiation based on a current change in the radiation imaging apparatus. Can be generated.

(Third embodiment)
Next, a third embodiment will be described.

<1. Configuration of radiation imaging apparatus>
FIG. 17 is a diagram illustrating an example of an internal configuration of the radiation imaging apparatus 101 according to the third embodiment. Unlike the first embodiment, the radiation imaging apparatus 101 according to the third embodiment further includes a gain image memory 1701, but the other configurations are the same as those described with reference to FIG. Although the process up to the generation of the gain image is the same as that of the first embodiment, in the third embodiment, the generated gain image is transmitted from the image processing apparatus 105 to the radiation imaging apparatus 101 and stored in the gain image memory 1701. The gain image memory 1701 is composed of a nonvolatile memory such as a flash memory.

<2. Processing related to gain images>
FIG. 18 is a flowchart illustrating a procedure of processing relating to a gain image in the third embodiment. First, an operation when the radiation imaging apparatus 101 is activated for the first time will be described. In step S1801, communication connection between the radiation imaging apparatus 101 and the image processing apparatus 105 is established. In step S <b> 1802, the image processing apparatus 105 temporarily prohibits the imaging of the subject by the radiation imaging apparatus 101 during the operation of determining whether or not the radiation imaging apparatus holds a sensitivity correction image (gain image). Furthermore, the image processing apparatus 105 may output a display that allows the user to know that photographing is also prohibited.

  In step S1803, the image processing apparatus 105 determines whether the gain image of the currently connected radiation imaging apparatus 101 is held in the image processing unit 1005 or the storage device 1007. If it is determined that the gain image is held, the process advances to step S1807. On the other hand, if it is determined that the gain image is not held, the processing proceeds to S1804. Since this is the first activation, the gain image is not held, and the process proceeds to S1804.

  In step S <b> 1804, the radiation imaging apparatus 101 determines whether a gain image is held in the gain image memory 1701. If it is determined that the gain image is held, the process advances to step S1805. On the other hand, if it is determined that the gain image is not held, the process proceeds to S1806.

  In step S <b> 1805, the image processing apparatus 105 acquires a gain image from the radiation imaging apparatus 101. Thereafter, the process proceeds to S1807. In step S1806, the image processing apparatus 105 generates a gain image. The generation is as described in the first embodiment. When the generation of the gain image is completed, the gain image is held in the image processing unit 1005 or the storage device 1007 in the image processing apparatus 105 and transmitted to the radiation imaging apparatus 101. The radiation imaging apparatus 101 stores the received gain image in the gain image memory 1701.

  In step S <b> 1807, the image processing apparatus 105 permits the subject to be photographed by the radiation imaging apparatus 101 and enters a state where the subject can be photographed. Thus, the processes in the flowchart of FIG. 18 are completed.

  Next, an operation when the same radiation imaging apparatus 101 and image processing apparatus 105 are activated again will be described. Each process of S1801 and S1802 is the same, but since the image processing apparatus 105 holds the gain image of the corresponding radiation imaging apparatus 101, YES is obtained in S1803. In step S1807, shooting is permitted and the process ends.

  Further, an operation when the radiation imaging apparatus 101 and another image processing apparatus different from the image processing apparatus 105 are connected will be described. Another image processing apparatus is assumed to have the same configuration as the image processing apparatus 105. Since another image processing apparatus does not hold the gain image of the radiation imaging apparatus 101, the result of S1803 is NO and the process proceeds to S1804. In S1804, since the radiation imaging apparatus 101 holds the gain image in the gain image memory 1701, the determination is YES, and the process proceeds to S1805. In step S1805, the gain image held by the radiation imaging apparatus 101 is transmitted to another image processing apparatus and stored in the image processing unit 1005 or the storage device 1007.

  In addition, in order to distinguish which radiation imaging apparatus the gain image held by the image processing apparatus 105 is for, it is managed by giving identification information such as a unique number or symbol to the radiation imaging apparatus. The image may be managed with its identification information. In the present embodiment, the gain image is generated by the image processing apparatus 105, but may be performed by the radiation imaging apparatus 101.

  As described above, according to the present embodiment, a defect-free sensitivity correction image (gain image) can be obtained even when imaging is performed by detecting radiation irradiation based on a current change in the radiation imaging apparatus. Can be generated.

(Fourth embodiment)
Next, a fourth embodiment will be described. FIG. 19 is a diagram illustrating an example of an internal configuration of the radiation imaging apparatus 101 according to the fourth embodiment. In the fourth embodiment, the radiation imaging apparatus 101 further includes a gain correction unit 1901 in addition to the configuration with reference to FIG. 17 in the third embodiment. The gain image is generated by the image processing apparatus 105, and the gain image is transmitted to the radiation imaging apparatus 101 and stored in the gain image memory 1701. A gain correction unit 1901 performs gain correction by performing an operation corresponding to division on the gain image read from the gain image memory 1701 on the image obtained by photographing the subject and offset-corrected by the offset correction unit 204. When this processing is implemented in hardware, in order to reduce the increase in hardware scale due to the division circuit, both are converted into logarithms using a logarithmic conversion lookup table and then subtracted. Also good. As shown in FIG. 19, when the image is previously divided into reduced images by the image dividing unit 202 as shown in FIG. 19, the gain image is also divided in advance in the same way as the reduced image, and the gain image is obtained. It is desirable to be held in the memory 1701.

  When the gain image is continuously held by the image processing apparatus 105, the gain image memory 1701 may be a volatile memory such as a DRAM. In this case, every time the radiation imaging apparatus 101 is activated, a gain image is transmitted from the image processing apparatus 105 to the radiation imaging apparatus 101 and held in the gain image memory 1701. When the gain image is continuously held by the radiation imaging apparatus 101, the gain image memory 1701 may be a non-volatile memory such as a flash memory. In this case, when a gain image is generated by the image processing apparatus 105, it is transmitted to the radiation imaging apparatus 101 and stored in the gain image memory 1701. Note that the gain image may be developed in a volatile memory such as a DRAM when the radiation imaging apparatus 101 is started in order to shorten the gain image readout time during gain correction. In the present embodiment, an example in which the gain image is generated by the image processing apparatus 105 has been described. However, the gain image may be generated by the radiation imaging apparatus 101 as in the second embodiment.

  From the first embodiment to the fourth embodiment, the radiation imaging apparatus 101 includes the image dividing unit 202 and the image processing apparatus 105 includes the divided image combining unit 1002 for speeding up the preview. It is not essential for implementation. Further, each of the radiation image and the offset image may be sent to the image processing apparatus 105, and the offset correction may be performed in the image processing apparatus 105. Further, prior to radiographic imaging of a subject, an offset image may be acquired in advance when the radiographic imaging apparatus 101 is turned on or when an imaging order is acquired, and offset correction may be performed using the acquired offset image. Further, the offset correction may be performed not in the radiation imaging apparatus 101 but in the image processing apparatus 105.

  As described above, according to the present invention, sensitivity correction is performed in an imaging method that eliminates the need for communication between the radiation imaging apparatus and the radiation generation apparatus by detecting radiation irradiation by a current change in the radiation imaging apparatus. Even when the image for use (gain image) is generated, the defect of the image for gain correction (gain image) can be removed, so that the occurrence of artifacts due to the sensitivity correction process can be reduced.

  In each of the embodiments described above, a plurality of radiation images having different defect positions are acquired, and an image of a region that does not include a defect among the plurality of radiation images is bonded and averaged based on information indicating the position of the defect. Thus, a sensitivity correction image may be generated. The pixel values of the pixels at the corresponding positions in the image of the region not including the defect may be averaged so that the addition number is the same for each pixel of the generated sensitivity correction image.

  It should be noted that the present invention is not limited to the process of performing the averaging process after creating a white image by the combining process, and the combining process and the adding average process may be executed together.

  In general, if the number of white images to be added is different for each region, the random noise reduction rate is different. However, this configuration makes it possible to make the random noise reduction rate uniform for each region.

(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.

  101: Radiation imaging device, 102: Radiation tube, 103: Radiation generation device, 104: Control device, 105: Image processing device, 201: Radiation sensor unit, 202: Image dividing unit, 203: Image memory, 204: Offset Correction unit, 205: Communication unit, 302: Radiation sensor control unit, 303: Scanning unit, 305: Detection unit, 308: Image generation unit, 1001: Communication unit, 1002: Divided image composition unit, 1003: Gain image generation unit, 1004: Defect correction information preprocessing unit, 1005: Image processing unit, 1401: Gain image generation unit, 1402: Image memory, 1403: Offset correction unit, 1501: Determination unit, 1502: Image buffer for composition, 1503: Composition unit , 1504: Averaging unit, 1505: Gain image buffer, 1701: Gain image memory, 1901: Gain compensation Part

Claims (29)

Photographed without placing an object, an acquisition unit that acquires information indicating a plurality of radiographic images which the position of the defect is different, the position of the defect in the radiation image,
Generating means for generating a sensitivity correction image not including the defect based on the plurality of radiation images and information indicating the position of the defect;
An image processing apparatus comprising: The acquisition means acquires a plurality of radiation images including the defect and information indicating the position of the defect from a radiation imaging apparatus that detects radiation irradiation by an internal current change and transitions to an imaging state. The image processing apparatus according to claim 1, wherein: The image processing apparatus according to claim 1, wherein the information indicating the position of the defect includes information specifying at least one of a position and a width of the defect generated in the radiation image.   And a determination unit configured to determine whether or not the sensitivity correction image can be generated based on a relationship between the defect position information of the first radiation image and the defect position information of the second radiation image. The image processing apparatus according to claim 1, wherein the image processing apparatus is characterized.   The determination means can generate the sensitivity correction image based on the relationship between the defect position information and defect width information of the first radiation image and the defect position information and defect width information of the second radiation image. The image processing apparatus according to claim 4, wherein it is determined whether or not the image processing is in progress. 5. The acquisition unit according to claim 4, wherein when the determination unit determines that a sensitivity correction image that does not include the defect cannot be generated, the acquisition unit newly acquires a radiation image and information indicating a position of the defect. 5. The image processing apparatus according to 5.   The image processing apparatus according to claim 1, wherein the generation unit generates a plurality of the sensitivity correction images and averages the plurality of sensitivity correction images.   The image according to any one of claims 1 to 7, further comprising image processing means for performing sensitivity correction processing on a radiation image based on the sensitivity correction image generated by the generation means. Processing equipment.   The image processing apparatus according to claim 1, further comprising a transmission unit that transmits the sensitivity correction image generated by the generation unit to a radiation imaging apparatus.   The image processing apparatus according to claim 8, wherein the image processing unit converts the sensitivity correction image and the corrected radiation image into logarithms prior to the sensitivity correction processing.   9. The image processing apparatus according to claim 1, further comprising notification means for notifying a user of an operation necessary for generating the sensitivity correction image via a display device. . Before Symbol generating means generates the sensitivity correction image by bonding the image of the region not including the defect and to averaging of the plurality of radiographic images based on the information indicating the position of the defect,
The generating means adds and averages the pixel values of corresponding pixels in the image of the region so that the number of additions is the same for each pixel of the sensitivity correction image generated by the generating means. The image processing apparatus according to claim 1. An acquisition unit configured to acquire a plurality of radiation images including a defect photographed without arranging a subject, and information on the defect included in the radiation image;
Determining means for determining whether or not a sensitivity correction image not including the defect can be generated based on a relationship between the defect position information of the first radiographic image and the defect position information of the second radiographic image; ,
Generating means for generating the sensitivity correction image based on the plurality of radiation images and information on the defect when it is determined that the sensitivity correction image can be generated;
An image processing apparatus comprising: A radiation imaging apparatus that detects radiation irradiation by an internal current change and transitions to an imaging state,
Photographed without placing an object, an acquisition unit that acquires information indicating a plurality of radiographic images which the position of the defect is different, the position of the defect in the radiation image,
Generating means for generating a sensitivity correction image not including a defect based on the plurality of radiation images and information indicating the position of the defect;
A radiation imaging apparatus comprising: It further comprises detection means for detecting a change in the internal current while performing a scan for switching the ON state / OFF state by sequentially selecting the sensors for each row according to a predetermined condition,
The radiation imaging apparatus according to claim 14 , wherein the information indicating the position of the defect includes information indicating a row number scanned at a time when the internal current exhibits a predetermined change. The radiographic apparatus according to claim 14 or 15, further comprising a nonvolatile memory for retaining the sensitivity correction image. A radiation imaging apparatus that detects radiation irradiation by an internal current change and transitions to an imaging state,
An acquisition unit configured to acquire a plurality of radiation images including a defect photographed without arranging a subject, and information on the defect included in the radiation image;
Determining means for determining whether or not a sensitivity correction image not including the defect can be generated based on a relationship between the defect position information of the first radiographic image and the defect position information of the second radiographic image; ,
Generating means for generating the sensitivity correction image based on the plurality of radiation images and information on the defect when it is determined that the sensitivity correction image can be generated;
A radiation imaging apparatus comprising: A radiation generating device that generates and irradiates radiation, a radiation imaging device that detects radiation irradiation by an internal current change and transitions to an imaging state, and an image that performs predetermined processing on a radiation image acquired from the radiation imaging device A radiography system including a processing device,
Photographed without placing an object, an acquisition unit that acquires information indicating a plurality of radiographic images which the position of the defect is different, the position of the defect in the radiation image,
Generating means for generating a sensitivity correction image not including a defect based on the plurality of radiation images and information indicating the position of the defect;
A radiation imaging system comprising: When the image processing apparatus does not hold the image for sensitivity correction of the radiation imaging apparatus,
When the radiation imaging apparatus holds a sensitivity correction image, the image processing apparatus acquires the sensitivity correction image from the radiation imaging apparatus,
The radiation imaging system according to claim 18 , wherein when the radiation imaging apparatus does not hold a sensitivity correction image, the image processing apparatus generates a sensitivity correction image. The radiation imaging apparatus and the sensitivity correction image corresponding to the radiation imaging apparatus are managed with specific identification information,
20. The radiation imaging system according to claim 19 , wherein whether or not the radiation imaging apparatus holds a sensitivity correction image is determined based on the identification information. The radiation imaging system according to claim 19 or 20 wherein the radiation imaging device in determining whether or not the operation holds the sensitivity correction image is characterized in that imaging by the radiation imaging apparatus is prohibited. The radiation imaging apparatus divides the radiation image for each pixel position according to a predetermined condition, and sequentially transmits the reduced image with a small number of pixels to the image processing apparatus for each reduced image,
The image processing apparatus, the radiation imaging apparatus based on the plurality of reduced images received from claims 18 to 21, characterized in that reconfiguring the plurality of types of the preview image and the divided front of images of different resolution The radiation imaging system according to any one of the above. A radiation generating device that generates and irradiates radiation, a radiation imaging device that detects radiation irradiation by an internal current change and transitions to an imaging state, and an image that performs predetermined processing on a radiation image acquired from the radiation imaging device A radiography system including a processing device,
An acquisition unit configured to acquire a plurality of radiation images including a defect photographed without arranging a subject, and information on the defect included in the radiation image;
Determining means for determining whether or not a sensitivity correction image not including the defect can be generated based on a relationship between the defect position information of the first radiographic image and the defect position information of the second radiographic image; ,
Generating means for generating the sensitivity correction image based on the plurality of radiation images and information on the defect when it is determined that the sensitivity correction image can be generated;
A radiation imaging system comprising: A control method for an image processing apparatus, comprising:
Acquiring means is captured without placing the object, a step of acquiring the information indicating a plurality of radiographic images which the position of the defect is different, the position of the defect in the radiation image,
A step of generating a sensitivity correction image that does not include a defect based on the plurality of radiation images and information indicating the position of the defect; and
A control method for an image processing apparatus, comprising: A control method for an image processing apparatus, comprising:
A step of acquiring a plurality of radiation images including a defect photographed without arranging a subject, and information on the defect included in the radiation image;
Based on the relationship between the defect position information of the first radiographic image and the defect position information of the second radiographic image, the determination unit determines whether it is possible to generate a sensitivity correction image that does not include the defect. And a process of
A step of generating the sensitivity correction image based on the plurality of radiation images and information on the defect when it is determined that the generation unit is capable of generating the sensitivity correction image;
A control method for an image processing apparatus, comprising: A method for controlling a radiation imaging apparatus that detects radiation irradiation by an internal current change and transitions to an imaging state,
Acquiring means is captured without placing the object, a step of acquiring the information indicating a plurality of radiographic images which the position of the defect is different, the position of the defect in the radiation image,
A step of generating a sensitivity correction image that does not include a defect based on the plurality of radiation images and information indicating the position of the defect; and
A control method for a radiation imaging apparatus, comprising: A method for controlling a radiation imaging apparatus that detects radiation irradiation by an internal current change and transitions to an imaging state,
A step of acquiring a plurality of radiation images including a defect photographed without arranging a subject, and information on the defect included in the radiation image;
Based on the relationship between the defect position information of the first radiographic image and the defect position information of the second radiographic image, the determination unit determines whether it is possible to generate a sensitivity correction image that does not include the defect. And a process of
A step of generating the sensitivity correction image based on the plurality of radiation images and information on the defect when it is determined that the generation unit is capable of generating the sensitivity correction image;
A control method for a radiation imaging apparatus, comprising: The program for making a computer perform each process of the control method of the image processing apparatus of Claim 24 or 25 . The program for making a computer perform each process of the control method of the radiography apparatus of Claim 26 or 27 .

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