JP2006304839A - Optical or radiation imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiation imaging apparatus which can provide a natural light or radiographic image by interpolating the missing picture elements even when missing picture elements are continuously distributed. <P>SOLUTION: The imaging sensor of an FPD 4 detects X rays transmitting a subject M and obtains an X-ray detection signal through an A/D converter 9. A picture element random number relating section 15 prepares related information in which picture elements other than missing picture elements in the vicinity of interpolated picture elements to be interpolated are related to a random number which possibly appear and a selection section 17 selects picture elements corresponding to a random number occurring in a random number generator 19 by referring to the related information. An interpolation section 21 interpolates interpolated picture elements by using the picture elements selected by the selection section 17. Since the missing picture elements as interpolated picture elements are interpolated by the picture elements selected, even when the missing picture elements are continuously distributed, picture elements to be used for interpolation can be scattered. Consequently a natural light or radiation images can be acquired. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light or radiation imaging apparatus used in the medical field, industrial fields such as non-destructive inspection, RI (Radio Isotope) inspection, and optical inspection, and particularly corresponds to an image sensor for detecting light or radiation. The present invention relates to a technique for interpolating attached pixels.

  In recent years, two-dimensional imaging sensors using semiconductor films have been developed as radiation imaging sensors.

  For example, an X-ray surface detection sensor that detects X-rays as radiation is configured by depositing an amorphous selenium (a-Se) film on thin film transistors, pixel electrodes, and storage capacitors arranged in a two-dimensional matrix. (For example, refer nonpatent literature 1). With this configuration, the X-ray surface detection sensor includes a plurality of imaging elements, such as a thin film transistor, a charge collection electrode, and an amorphous selenium film.

  When an X-ray image transmitted through the subject is projected onto the X-ray surface detection sensor, a charge signal proportional to the density of the X-ray image is generated in the amorphous selenium film. The generated charge signal is collected by the pixel electrode (storage capacitor), and after being integrated for a predetermined time (referred to as “storage time”), is read out through the thin film transistor.

  The charge signal read out to the outside is digitized by an A / D converter and subjected to image processing to generate an X-ray image. This X-ray image is composed of a plurality of pixels corresponding to the image sensor.

  Such an X-ray surface detection sensor has a large device area and a considerably large number of image sensors included therein (for example, 4096 vertical elements x 4096 horizontal elements). For this reason, there has been a problem that an image pickup device that cannot output a charge signal corresponding to the density of the irradiated X-ray image is generated as the manufacturing yield problem.

  When an X-ray image is acquired based on a charge signal obtained from such an image sensor, the pixel corresponding to the image sensor cannot display an X-ray image correctly, but also appears white or black, Inconvenience arises.

  As a method of interpolating such a pixel (hereinafter simply referred to as “missing pixel”), “the median value of a plurality of neighboring pixels is calculated, and the output of the missing pixel is replaced with the value” is devised. (For example, refer to Patent Document 1).

JP 7-336605 A W. Zhao, et al., “A flat detector for digital radiology using active matrix readout of amorphous selenium,” Proc. SPIE Vol. 2708, pp523-531, 1996.

  According to the conventional method, it is very effective when the defective pixel is scattered by one pixel. However, when a plurality of defective pixels are continuously distributed, for example, when a pixel group extending in 5 × 5 pixels is a defective pixel, or pixels extending in 2 vertical columns are defective pixels (“line defect In other cases, the entire region surrounded by the defective pixel is replaced with a similar value. For this reason, the interpolated X-ray image becomes extremely unnatural because the interpolated pixel area is completely filled or horizontal stripes are repeatedly generated in the vertical line of the line defect.

  The present invention has been made in view of such circumstances, and even when defective pixels are continuously distributed, a natural light or radiation image can be obtained by interpolating the defective pixels. An object is to provide a radiation imaging apparatus.

In order to achieve such an object, the present invention has the following configuration.
That is, the invention described in claim 1 includes an imaging sensor in which a plurality of imaging elements that output an output signal in response to light or radiation are arranged, and is an interpolation target among pixels associated with the imaging element. In a light or radiation imaging apparatus that interpolates an interpolation pixel, a pixel other than a defective pixel that is located in the vicinity of the interpolation pixel and that is associated with a random number that can appear, is a pixel corresponding to the generated random number Selection means for selecting and interpolation means for interpolating the output signal of the interpolation pixel based on the output signal of the pixel selected by the selection means, and each of the missing pixels is interpolated as the interpolation pixel. It is a feature.

  [Operation / Effect] According to the first aspect of the present invention, the pixel used to interpolate the interpolated pixel is selected by the selection means using a random number, and therefore is uniquely determined by the position of the interpolated pixel. It is scattered. Since each defective pixel is interpolated by the pixels thus selected, even when the defective pixels are continuously distributed, the pixels used to interpolate them can be scattered.

  For this reason, even in a region where defective pixels are continuously distributed in a light or radiation image, after interpolation, the noise level is similar to that of the surrounding region, and the continuity of the noise level can be maintained. Therefore, a natural light or radiation image can be acquired.

  The invention according to claim 2 is the light or radiation imaging apparatus according to claim 1, wherein the random number is weighted with an appearance rate, and a pixel other than a defective pixel is closer to the interpolation pixel. It is characterized by being associated with a random number having a high appearance rate.

  [Operation / Effect] As the pixels used to interpolate the interpolated pixels, it is possible to increase the probability that the pixels closer to the interpolated pixels are selected.

  The invention according to claim 3 is the optical or radiation imaging apparatus according to claim 1 or 2, wherein the random number is a Gaussian distributed random number, and the distance from the interpolated pixel is long, and other than the defective pixel. The pixel is characterized in that the appearance rate of the associated random number decreases.

  [Operation / Effect] According to the invention described in claim 3, if it is a Gaussian distributed random number, the appearance rate of the random number can be suitably weighted.

  According to a fourth aspect of the present invention, in the light or radiation imaging apparatus according to any one of the first to third aspects, the interpolation means outputs an output signal of the pixel selected by the selection means to the interpolation pixel. The output signal is replaced with the output signal.

  [Operation / Effect] According to the invention described in claim 4, the interpolation pixel can be interpolated by replacing the output signal of the selected pixel with the output signal of the interpolation pixel.

  According to a fifth aspect of the present invention, in the light or radiation imaging apparatus according to any one of the first to third aspects, the selection unit selects a plurality of pixels, and the interpolation unit selects An average value of the output signals of the plurality of pixels is obtained, and this is replaced with the output signal of the interpolated pixel.

  [Operation / Effect] According to the invention described in claim 5, the interpolation pixel can be interpolated by replacing the average value of the output signals of the plurality of selected pixels with the output signal of the interpolation pixel. .

  According to a sixth aspect of the present invention, in the light or radiation imaging apparatus according to any one of the first to third aspects, the selection unit selects a plurality of pixels, and the interpolation unit selects The intermediate value of the output signals of the plurality of pixels is replaced with the output signal of the interpolation pixel.

  [Operation / Effect] According to the invention described in claim 6, the interpolated pixels can be interpolated by replacing the intermediate values of the output signals of the plurality of selected pixels with the output signals of the interpolated pixels. it can.

  The present specification also discloses an invention related to the following interpolation method.

  (1) A defect located in the vicinity of an interpolation pixel in an interpolation method for interpolating an interpolation pixel to be interpolated among pixels associated with a plurality of imaging elements that output an output signal in response to light or radiation. A process of selecting a pixel corresponding to the generated random number from among the pixels other than the pixel associated with the appearing random number, and the output signal of the interpolation pixel based on the output signal of the selected pixel And an interpolation method.

  According to the invention described in (1) above, the pixels used to interpolate the interpolation pixels are selected using random numbers, and therefore are not uniquely determined by the positions of the interpolation pixels and are scattered. Since each defective pixel is interpolated by the pixels thus selected, even when the defective pixels are continuously distributed, the pixels used to interpolate them can be scattered. For this reason, in the light or radiographic image, the region where the defective pixels are continuously distributed also has a noise feeling similar to that of the surrounding region, and the continuity of the noise level can be maintained. Therefore, a natural light or radiation image can be acquired.

  According to the radiation imaging apparatus of the present invention, the pixels used to interpolate the interpolation pixels are selected by the selection means using random numbers, and therefore are not uniquely determined by the position of the interpolation pixels and are scattered. Since each defective pixel is interpolated by the pixels thus selected, even when the defective pixels are continuously distributed, the pixels used to interpolate them can be scattered. For this reason, in the light or radiographic image, the region where the defective pixels are continuously distributed also has a noise feeling similar to that of the surrounding region, and the continuity of the noise level can be maintained. Therefore, a natural light or radiation image can be acquired.

Embodiment 1 of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram illustrating the overall configuration of the X-ray imaging apparatus according to the first embodiment. In this embodiment, a medical X-ray imaging apparatus will be described as an example of a radiation imaging apparatus.

  The imaging unit 1 of the X-ray imaging apparatus includes a top plate 2 on which a subject M as a subject is placed, an X-ray tube 3 that emits X-rays toward the subject M, and X-rays that have passed through the subject M. And a flat panel X-ray detector (hereinafter referred to as “FPD” as appropriate) 4.

  In addition, the X-ray imaging apparatus includes a movement control unit 5 that moves the top plate 2, the X-ray tube 3, and the FPD 4, an X-ray tube control unit 6 that controls the tube voltage and tube current of the X-ray tube 3, and the FPD 4. And an FPD controller 7 for reading and controlling the charge signal.

  Further, an A / D converter 9 that digitizes the charge signal read from the FPD 4 and converts it into an X-ray detection signal, and a digital image processing unit 10 that acquires an X-ray image from the X-ray detection signal are provided. . The X-ray detection signal corresponds to the output signal in the present invention.

  The digital image processing unit 10 further includes a missing pixel information storage unit 13, a selection range determination unit 14, a pixel random number related unit 15, a selection unit 17, a random number generator 19, an interpolation unit 21, and an image generation unit. 23. Further, the interpolation unit 21 includes a calculation unit 25 and a replacement unit 27.

  The X-ray tube 3 and the FPD 4 are disposed to face each other with the subject M interposed therebetween. The movement control unit 5 horizontally moves or rotates the X-ray tube 3 and the FPD 4 so that this state is maintained. The X-ray tube 3 irradiates the subject M with a predetermined dose of X-rays based on the control of the X-ray tube control unit 6. In FIG. 1, the irradiated X-ray is schematically shown by a one-dot chain line.

  FIG. 2 is a vertical cross-sectional view of the main part of the FPD 4, and FIG. 3 is a plan view of the main part of the FPD 4. As shown in the figure, in order from the X-ray incident side, a common electrode 31 for applying a bias voltage, an X-ray conversion layer 33 for converting X-rays into charge signals, a pixel electrode 35 for collecting the converted charge signals, and active A matrix substrate 37 is laminated. That is, the FPD 4 is a direct conversion type that directly converts X-rays into electric charges.

  Examples of the X-ray conversion layer 33 include amorphous and selenium. The active matrix substrate 37 is exemplified by a glass substrate having electrical insulation.

  The pixel electrodes 35 are separately formed in a two-dimensional matrix in plan view. Furthermore, on the active matrix substrate 37, for each pixel electrode 35, a storage capacitor (also referred to as “capacitor”) Ca that stores a charge signal, a pixel electrode 35 and a storage capacitor Ca are connected to a source S, and a charge signal is stored. A thin film transistor (Thin Film Transistors) Tr which is a switch element for taking out the element is formed separately. The one set of pixel electrode 35, the storage capacitor Ca, and the thin film transistor Tr constitute one image sensor d together with the X-ray conversion layer 33 and the common electrode 31 in a region corresponding thereto.

  Therefore, it can be seen that a large number of image sensors d are arranged in a two-dimensional matrix on the detection surface of the FPD 4 as shown in FIG. An image sensor 45 is formed by a set of these multiple image sensors d. For example, on the detection surface of the imaging sensor 45 having a size of about 30 cm in length × 30 cm in width, 4096 × vertical 4096 image sensors d are arranged. Each image sensor d has a correspondence relationship with each pixel constituting the generated X-ray image.

  Further, on the active matrix substrate 37, a gate bus line 41 is laid for each row of the image sensors d, and a data bus line 43 is laid for each column of the image sensors d. Each gate bus line 41 is commonly connected to the gates of the thin film transistors Tr in each row. Each data bus line 43 is commonly connected to the drains of the thin film transistors Tr in each column.

  The FPD 4 further includes a gate driver circuit 46 on one end side of the active matrix substrate 37 and an amplifier array circuit 47 on the other end side.

  Each gate bus line 41 drawn from the active matrix substrate 37 is connected to the gate driver circuit 46.

  The amplifier array circuit 47 is provided with a plurality of amplifiers 49, and each data bus line 43 led out from the active matrix substrate 37 is connected to each amplifier 49 one by one.

  The operation in the FPD 4 will be described. When X-rays are incident on the image sensor 45 with a bias voltage applied to the common electrode 31, a charge signal is generated in the X-ray conversion layer 33, and this charge signal is stored in the storage capacitor Ca via the pixel electrode 35. . The gate bus line 41 transmits the scanning signal from the gate driver circuit 46 and applies it to the gate of the thin film transistor Tr. As a result, the charge signal stored in the storage capacitor Ca is read out to the data bus line 43 via the thin film transistor Tr that has been turned on. The charge signal read through each data bus line 43 is amplified by an amplifier 49. The amplified charge signal is output to the outside of the FPD 4 and input to the A / D converter 9.

  Further, the FPD control unit 7 controls an operation of reading detection data from the above-described imaging sensor 45.

  Next, each part of the digital image processing unit 10 will be described. The various functions of each part of the digital image processing unit 10 are a central processing unit (CPU) that executes various processes, a RAM (Random-Access Memory) that is a work area for arithmetic processes, and a fixed memory that stores various types of information. This is realized by a storage medium such as a disk.

  The missing pixel information storage unit 13 stores address information of missing pixels. This address information is written in a storage medium in advance when the FPD 4 is manufactured. In this embodiment, the defective pixel is a pixel that needs to be interpolated at least.

  The address information is information such as two-dimensional coordinates for identifying the position of the defective pixel.

  The selection range determination unit 14 reads the address information of the missing pixel from the missing pixel information storage unit 13 and sets any missing pixel as an interpolation target. Here, a pixel to be interpolated is particularly distinguished from an “interpolated pixel”. Then, pixels other than the defective pixel located in the vicinity of the interpolation pixel are extracted. Therefore, the extracted pixels are all pixels that are not defective pixels (also referred to as “non-defective pixels”).

  Here, in the present embodiment, the vicinity is set to a range of 5 vertical pixels and 5 horizontal pixels centering on the interpolation pixel. The neighborhood is not limited to this range, and the design can be appropriately changed, for example, a range of 9 pixels in the vertical direction and a range of 9 pixels in the horizontal direction.

  The pixel random number related unit 15 creates related information in which the selected range determining unit 14 associates the extracted pixels with random numbers that can be generated by the random number generator 19.

  The selection unit 17 refers to the related information created by the pixel random number related unit 15 and selects a pixel corresponding to the random number generated by the random number generator 19. The selection unit 17 corresponds to the selection means in this invention.

  The random number generator 19 generates a Gaussian distributed random number (Gaussian distributed random number) and outputs it to the selection unit 17. The random number generator corresponds to random number generation means.

  The calculation unit 25 performs a predetermined calculation based on the X-ray detection signal of the selected pixel among the X-ray detection signals output from the A / D converter 9. The replacement unit 27 replaces the calculated value obtained by the calculation unit 25 with the X-ray detection signal of the interpolation pixel. The interpolation unit 21 including the calculation unit 25 and the replacement unit 27 corresponds to the interpolation means in the present invention.

  The image generation unit 23 generates an X-ray image based on an X-ray detection signal of each pixel (a calculated value replaced for a pixel interpolated as an interpolation pixel).

  Next, each operation of the X-ray imaging apparatus according to Embodiment 1 will be described with reference to FIGS. FIG. 4 is a flowchart showing a process of acquiring an X-ray image, FIG. 5 is a schematic diagram showing a configuration of address information of a defective pixel, and FIG. 6 shows a pixel extracted by the selection range determination unit 14. FIG. 7 is a schematic diagram illustrating a configuration of related information created by a pixel random number related unit, in which a pixel and a random number are associated with each other.

<Step S1> Irradiate X-rays Under the control of the movement control unit 5, the top plate 2, the X-ray tube 3, and the FPD 4 are arranged at predetermined positions. Based on the control of the X-ray tube control unit 6, X-rays are emitted from the X-ray tube 3 toward the subject M. X-rays transmitted through the subject M are detected by the imaging sensor 45.

  A charge signal read from the image sensor 45 under the control of the FPD control unit 7 is output from the FPD 4 and input to the A / D converter 9. The A / D converter 9 digitizes the charge signal and outputs an X-ray detection signal.

<Step S <b>2> The selection range determination unit 14 reads any missing pixel address information from the missing pixel information storage unit 13. Then, any of the missing pixels is set as an interpolation pixel.

  FIG. 5 is a schematic diagram illustrating a configuration of address information of a defective pixel. For the sake of convenience, it is assumed that the pixels associated with each image sensor d are a total of 49 pixels, 7 pixels high and 7 pixels wide. Each pixel G is appended with numbers from “11” to “77”, which is address information, and is appended with “K” if it is a defective pixel. In FIG. 5, each defective pixel is indicated by hatching. That is, G11, G12, and the like are pixels other than defective pixels. G16K and G22K are defective pixels.

  In step S2, the description will be continued by taking as an example the case where the defective pixel G44K is an interpolation pixel.

<Step S <b>3> Extracting pixels other than the missing pixels that are located in the vicinity of the interpolation pixel Subsequently, the selection range determination unit 14 is a pixel G that is located in the vicinity of the interpolation pixel G and is a pixel G other than the missing pixel G. Extract.

  Specifically, the pixels located in the vicinity of the interpolation pixel G44K are all 24 pixels other than the interpolation pixel G44K in the range of 5 vertical pixels and 5 horizontal pixels centering on the interpolation pixel G44K. Further, since the pixels are other than the defective pixels, the defective pixels (G22K, G25K, G36K, G45K, G53K, G64K, G65K, G66K) are excluded. As a result, the extracted pixels are pixels that are not 15 defective pixels as shown in FIG.

<Step S <b>4> The pixel random number association unit 15 associates the extracted pixel with the random number that can be generated by the random number generator 19 by the selection range determination unit 14. Create information.

  In the present embodiment, among the extracted pixels, related information associated with a random number having a higher appearance rate is created as the pixel is closer in spatial distance to the interpolation pixel G44K.

  In FIG. 6, numbers (1) to (15) are assigned to the extracted pixels in order of increasing spatial distance from the interpolation pixel G44K (not shown).

  According to this order, the extracted pixels are sorted as shown in the upper part of FIG. On the other hand, if the random numbers that can appear are r1 to r15 in descending order of appearance rate, the random numbers having the highest appearance rate are correlated in order from the pixel G34 that is closer to the interpolation pixel G44K to the far pixel G46 ( (See the lower part of FIG. 7). In this way, information associated with random numbers that can appear as extracted pixels is related information.

  The random number generator 19 of the present embodiment generates a Gaussian distributed random number (Gaussian distributed random number), and the appearance rate of the random number is weighted.

  FIG. 8 schematically shows the relationship between the random numbers that can be generated by the Gaussian distributed random numbers and their appearance rates. Thus, the random number r1 has the highest appearance rate, and the random number r15 has a characteristic that the appearance rate decreases.

<Step S5> A random number is generated by the random number generator 19 that selects a pixel corresponding to the generated random number. The generated random number is output to the selection unit 17. The selection unit 17 refers to the related information created by the pixel random number related unit 15 and selects a pixel corresponding to the random number generated by the random number generator 19.

  In this embodiment, the random number generator 19 generates a random number three times, and the selection unit 17 selects three pixels corresponding to each random number.

<Step S6> The interpolating pixel is interpolated by the selected pixel. The arithmetic unit 25 converts the X-ray detection signal output from the A / D converter 9 into the X-ray detection signal of the pixel selected by the selection unit 17. Based on this, a predetermined calculation is performed. Then, the replacement unit 27 replaces the X-ray detection signal of the interpolation pixel in the X-ray detection signal output from the A / D converter 9 with the calculated value obtained by the calculation unit 25.

  In this embodiment, the calculation unit 25 receives from the A / D converter 9 the X-ray detection signals of the three pixels selected by the selection unit 17. Then, the average value of the X-ray detection signals of these three pixels G is calculated.

  The replacement unit 27 replaces the X-ray detection signal of the interpolation pixel G with the average value obtained by the calculation unit 25.

<Step S7> Have all the missing pixels been interpolated as interpolation pixels?
When interpolation is performed by performing the processing from step S2 to step S6 using all the defective pixels as interpolation pixels, the process proceeds to step S8. On the other hand, if not all the missing pixels are interpolated as interpolation pixels, the process returns to step S2 and the interpolation is sequentially repeated with the missing pixels not interpolated, for example, the pixel G45K as interpolation pixels.

<Step S8> Generate X-ray Image Based on the X-ray detection signal output from the replacement unit 27 (for the pixel interpolated as the interpolation pixel, the replaced calculated value), the image generation unit 23 generates the X-ray image. Is generated.

  As described above, according to the X-ray imaging apparatus according to the first embodiment, the selection unit 17 that selects the pixels used to interpolate the interpolation pixels by the random number is provided, so that it is uniquely determined by the position of the interpolation pixels. It is scattered. Since each defective pixel is interpolated by the pixels thus selected, even when the defective pixels are continuously distributed, the pixels used to interpolate them can be scattered. For this reason, in an X-ray image, a region where defective pixels are continuously distributed also has a noise feeling similar to that of the surrounding region after interpolation, and the continuity of the noise level can be maintained. Therefore, a natural light or radiation image can be acquired.

  Further, the pixel random number related unit 15 creates the related information associated with the random number having a higher appearance rate as the pixel closer to the interpolation pixel among the pixels extracted by the selection range determination unit 14, so that interpolation is performed. It is possible to increase the probability that a pixel closer to the pixel is selected.

  In addition, since the random number generator 19 uses Gaussian distributed random numbers (Gaussian distributed random numbers), the appearance rate of random numbers can be weighted appropriately.

  The present invention is not limited to the above-described embodiment, and can be modified as follows.

  (1) In the above-described embodiment, the random number generator 19 uses a Gaussian distributed random number (Gaussian distributed random number), but is not limited thereto. Any random number in which the relationship between the random number and the appearance rate is changed and the appearance rate is weighted can be appropriately selected.

  For example, as shown by a solid line in FIG. 9, the relationship between the random number and the appearance rate may change linearly, or may change stepwise as shown by a dotted line.

  (2) Further, although the random number generator 19 generates random numbers weighted with the appearance rate, the random number generator 19 may be configured to use a uniform random number with a uniform appearance rate of each random number. In this case, the pixel random number related unit 15 arranges the pixels extracted by the selection range determining unit 14 in order of decreasing spatial distance from the interpolation pixel, and arranges the random numbers that can be generated in descending order of appearance rate. It is not necessary, and it is sufficient to create related information in which arbitrarily extracted pixels are associated with random numbers.

  (3) The interpolation unit 21 is configured to replace the average value of the X-ray detection signals of the three pixels selected by the selection unit 17 with the X-ray detection signal of the interpolation pixel, but is not limited thereto. . For example, the number of pixels selected by the selection unit 17 may be two, or four or more.

  In addition, the interpolation unit 21 may appropriately change the design so that the calculation unit 25 calculates other statistics such as an intermediate value of the X-ray detection signal of the pixel selected by the selection unit 17.

Further, the selection unit 17 is configured to select one pixel, and the interpolation unit 21 replaces the value of the X-ray detection signal of the selected pixel G with the X-ray detection signal of the interpolation pixel G. You may comprise.

  (4) The X-ray imaging apparatus according to the present embodiment has a configuration in which the selection range determination unit 14, the pixel random number related unit 15, the selection unit 17, and the random number generator 19 perform predetermined processing each time X-ray irradiation is performed. However, it is not limited to this.

  For example, the pixels extracted by the selection range determination unit 14 may be obtained in advance when each defective pixel is an interpolation pixel and stored in a predetermined storage medium. As a result, the selection range determination unit 14 can be omitted.

  Further, the related information created by the pixel random number related unit 15 may be created in advance for each missing pixel as an interpolation pixel and stored in a predetermined storage medium. Thereby, the pixel random number related part 15 can also be omitted.

  Furthermore, the random number generated by the random number generator 19 may be configured to use a previously generated random number. According to this, since it is not necessary to generate a random number for each X-ray irradiation, the random number generator 19 can be omitted. In addition, by using a random number generated in advance, interpolation information that is information that associates each missing pixel with a pixel that is used to interpolate these missing pixels is stored in a predetermined storage medium. The selection unit 17 can be omitted. In this way, the configuration of the digital image processing unit 10 can be simplified.

  (5) The image pickup device d of the above-described embodiment directly converts incident X-rays into charge signals by the X-ray conversion layer 33, but is not limited thereto. For example, an indirect imaging element that converts incident X-rays into light by a scintillator and converts the light into charge information by a semiconductor layer formed of a photosensitive material may be used.

  (6) The image sensor 45 of the present embodiment has a configuration in which a plurality of image sensors d are arranged in a two-dimensional matrix, but is not limited thereto. The image sensor 45 may be a one-dimensional line sensor as long as it includes a plurality of image sensors d.

  (7) In the above-described embodiments, the X-ray imaging apparatus detects the incidence of X-rays. However, what is incident is not limited to X-rays. It can also be applied to radiation other than X-rays (including neutron rays, γ rays, and β rays) or light.

  (8) In the above-described embodiment, the use of the X-ray detector is not specified, but may be applied to, for example, an X-ray imaging apparatus used in the medical field. Further, the present invention can be applied to apparatuses using radiation other than X-rays, and can also be applied to radiation imaging apparatuses used in industrial fields such as non-destructive inspection, RI (Radio Isotope) inspection, and optical inspection.

It is a block diagram which shows the whole structure of the X-ray imaging device which concerns on an Example. It is a vertical sectional view of the principal part of FPD. It is a top view of the principal part of FPD. It is a flowchart which shows the process which acquires an X-ray image. It is a schematic diagram which shows the structure of the address information of a defective pixel. It is a schematic diagram which shows the structure of the information of the pixel extracted by the selection range determination part. It is a schematic diagram which shows the structure of the relevant information which matched the pixel and the random number produced by the pixel random number relevant part. It is a schematic diagram which shows the relationship between the random number which can generate | occur | produce a Gaussian distribution random number, and an appearance rate. It is a schematic diagram which shows the relationship between the random number concerning a modification and an appearance rate.

Explanation of symbols

4 ... Flat panel X-ray detector (FPD)
DESCRIPTION OF SYMBOLS 13 ... Missing pixel information storage part 14 ... Selection range determination part 15 ... Pixel random number related part 17 ... Selection part 19 ... Random number generator 21 ... Interpolation part 25 ... Operation part 27 ... Replacement part 45 ... Imaging sensor M ... Subject d ... Image sensor G ... Pixel

Claims (6)

  A light or radiation imaging apparatus comprising an imaging sensor in which a plurality of imaging elements that output an output signal in response to light or radiation are arranged, and interpolating interpolation pixels to be interpolated among pixels associated with the imaging elements A selection unit that selects a pixel corresponding to the generated random number from among the pixels other than the defective pixel that are located in the vicinity of the interpolation pixel and that are associated with the random number that may appear, and the selection unit An optical or radiation imaging apparatus comprising: interpolation means for interpolating the output signal of the interpolation pixel based on the output signal of the selected pixel, and interpolating each defective pixel as the interpolation pixel.   2. The light or radiation imaging apparatus according to claim 1, wherein the random number is weighted by an appearance rate, and a pixel other than a defective pixel that is closer to the interpolation pixel is associated with a random number having a higher appearance rate. A light or radiation imaging apparatus.   3. The optical or radiation imaging apparatus according to claim 1, wherein the random number is a Gaussian distributed random number, and an appearance rate of a random number that is associated with a pixel other than a defective pixel that is far from the interpolation pixel. A light or radiation imaging apparatus, wherein   4. The light or radiation imaging apparatus according to claim 1, wherein the interpolation unit replaces an output signal of the pixel selected by the selection unit with an output signal of the interpolation pixel. 5. Light or radiation imaging device.   4. The light or radiation imaging apparatus according to claim 1, wherein the selection unit selects a plurality of pixels, and the interpolation unit averages output signals of the selected plurality of pixels. A light or radiation imaging apparatus characterized by obtaining a value and replacing it with an output signal of the interpolated pixel. 4. The light or radiation imaging apparatus according to claim 1, wherein the selection unit selects a plurality of pixels, and the interpolation unit intermediates output signals of the selected plurality of pixels. 5. A light or radiation imaging apparatus, wherein a value is replaced with an output signal of the interpolation pixel.

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