JP2009080055A - Method for inspecting pipe and radiographic non-destructive inspection apparatus - Google Patents

Method for inspecting pipe and radiographic non-destructive inspection apparatus Download PDF

Info

Publication number
JP2009080055A
JP2009080055A JP2007250402A JP2007250402A JP2009080055A JP 2009080055 A JP2009080055 A JP 2009080055A JP 2007250402 A JP2007250402 A JP 2007250402A JP 2007250402 A JP2007250402 A JP 2007250402A JP 2009080055 A JP2009080055 A JP 2009080055A
Authority
JP
Japan
Prior art keywords
image data
radiation
transmission image
subject
pipe
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
JP2007250402A
Other languages
Japanese (ja)
Other versions
JP4595979B2 (en
Inventor
Hiroshi Kamimura
Kojiro Kodaira
Yasushi Nagumo
Atsushi Nukaga
Noriyuki Sadaoka
上村  博
名雲  靖
紀行 定岡
小治郎 小平
淳 額賀
Original Assignee
Hitachi Ltd
株式会社日立製作所
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hitachi Ltd, 株式会社日立製作所 filed Critical Hitachi Ltd
Priority to JP2007250402A priority Critical patent/JP4595979B2/en
Priority claimed from EP20080007770 external-priority patent/EP1985998A1/en
Publication of JP2009080055A publication Critical patent/JP2009080055A/en
Application granted granted Critical
Publication of JP4595979B2 publication Critical patent/JP4595979B2/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Abstract

<P>PROBLEM TO BE SOLVED: To improve inspection efficiency in a non-destructive inspection conducted by radiographing pipes or the like installed in a plant or the like. <P>SOLUTION: A control processor comprises an image capture device for capturing transmission image data, a control device for controlling a position of the radiographing device, a transmission image data storage device for storing the transmission image data transmitted from the image capture device, a determination device for determining a part of a subject which requires reconfiguration of an image based on the transmission image data from the transmission image data storage device, and an image reconfiguration device for reconfiguring a cross sectional image or a three dimensional image of the subject based on the transmission image data. The inspection efficiency can be improved in the non-destructive inspection by radiographing the pipes or the like installed in the plant or the like. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a radiation nondestructive inspection system and a pipe inspection method.

  As a non-destructive inspection method for visualizing and inspecting the inside of a structure installed at a specific place such as a pipe installed in a nuclear power plant, a thermal power plant, a chemical plant, etc., the technologies of Non-Patent Documents 1 and 2 are used. It is disclosed.

Hamada, Katayama, "Piping thickness inspection device", Toshiba Review Vol.61, No.6, pp.68-71 (2006) B. Redmer, et. Al, "MOBILE 3D-X-RAY TOMOGRAPHY FOR ANALYSIS OF PLANAR DEFECTS IN WELDS BY" TOMOCAR "," 16th WCNDT proceedings (2004)

  However, the techniques disclosed in Non-Patent Documents 1 and 2 have a problem that the inspection time becomes long and the inspection efficiency decreases.

  Therefore, an object of the present invention is to improve inspection efficiency in nondestructive inspection by radiography of piping or the like installed in a plant or the like.

  The control arithmetic device of the present invention includes an image capturing device that captures the transmission image data, a control device that controls a position of the radiation imaging device, and a transmission that stores the transmission image data transmitted from the image capturing device. An image data storage device; a determination device for determining a portion of the subject that requires image reconstruction based on the transmission image data from the transmission image data storage device; and a tomographic image of the subject based on the transmission image data; An image reconstruction device that reconstructs a three-dimensional stereoscopic image is provided.

  ADVANTAGE OF THE INVENTION According to this invention, inspection efficiency can be improved in the nondestructive inspection by radiography of piping etc. which were installed in the plant etc.

  Radiation such as X-rays and γ-rays is applied to non-destructive inspection methods that visualize and inspect the inside of structures installed at specific locations, such as piping installed in nuclear power plants, thermal power plants, chemical plants, etc. There is a radiographic test (hereinafter referred to as “RT”) to be used. RT is a measurement of radiation irradiated to a structure to be examined (hereinafter referred to as “subject”) with a radiation detector placed on the opposite side of the radiation source across the subject. This is a method for capturing a two-dimensional transmission image. In the examination by RT, confirmation of the state inside the subject and measurement of the dimensions are performed using the photographed transmission image.

  There is [Non-patent Document 1] as an apparatus for inspecting the thinning of the plant piping by RT. In this document, a radiation source and a high-sensitivity image intensifier (radiation detector) are attached to a support mechanism called a C-shaped arm, and plant piping is scanned. And the transmission image of piping is image | photographed and the thinning amount is measured from the transmission image.

  Another non-destructive inspection method using radiation is computed tomography (CT). An industrial X-ray CT apparatus generally fixes an X-ray source and a radiation detector, and rotates a subject placed on a disk disposed between them. Then, by irradiating the subject with radiation while rotating the subject, a transmission image is taken from all around the subject, and a tomographic image of the subject is obtained by image reconstruction. The difference from the transmission image by RT is that a three-dimensional image inside the subject is obtained. For this reason, more detailed position information can be acquired about the internal structure of the subject.

  In addition, as a radiation CT apparatus for nondestructive inspection of piping, there is disclosed an apparatus for inspecting joints of pipe welds [Non-Patent Document 2]. This apparatus is an imaging apparatus based on an imaging method called laminography. In laminography, a radiation source and a radiation detector installed so as to face each other with a subject sandwiched between each other are moved in parallel and in opposite directions, thereby obtaining a tomographic image parallel to the movement direction of the radiation source and the radiation detector. It is a method of shooting. By changing the moving distance of the radiation detector with respect to the moving distance of the radiation source, the depth of the imaging tomographic plane viewed from the radiation source can be changed. The apparatus of [Non-Patent Document 2] is based on the imaging principle of laminography, and imaging is performed by attaching a small X-ray source and a radiation detector to a moving device mounted on a pipe. Imaging is performed by rotating the X-ray source in the circumferential direction of the pipe or scanning in the long axis direction of the pipe with the radiation detector fixed.

  However, each of the above methods has the following problems.

  RT has a problem that the appearance of the thinned portion generated in the pipe to be inspected changes depending on the photographing direction. This is because depth information in the imaging direction is superimposed by actually imaging a subject having a three-dimensional structure as a two-dimensional transmission image. For this reason, in RT, it is necessary to image the subject from a plurality of directions in order to search for an imaging direction in which the thinned portion of the pipe can be observed. This operation usually takes several minutes to several tens of minutes. It was.

  CT also requires that the subject be rotated or that the radiation source and radiation detector be rotated around the subject. However, in the case of piping installed in the plant, it is impossible to rotate the piping. Further, the circumference of the pipe is narrow, and there is usually no room for rotating the radiation source and the radiation detector around the pipe. That is, there has been a problem that conventional CT imaging cannot be performed on a structure installed in a narrow place such as a piping of a nuclear power plant, a thermal power plant, or a chemical plant.

  Also, in tomography of piping by laminography, the tomography is performed with the radiation detector fixed, so that one imaging range depends on the detector size of the radiation detector. The size of the radiation detector is several tens of centimeters. If the shooting time for one time is several minutes, the shooting time for the entire piping of several meters becomes enormous. Further, the scanning of the radiation source or the radiation detector is complicated, and it takes time for the alignment work.

  In addition, in laminography, when a plurality of tomographic images or three-dimensional stereoscopic images are generated by image reconstruction, there are problems that the calculation time is longer and the data capacity is larger than RT. If the inspection area of the piping that is the subject is as long as several meters, generating a tomographic image or a three-dimensional stereoscopic image of the entire inspection area may result in a huge amount of calculation time and data volume, which may impair the inspection efficiency. There is.

  In order to avoid the above problem, it is conceivable to perform CT imaging after first taking a transmission image over the entire length of the piping and specifying the inspection location. This is a method implemented in a medical X-ray CT apparatus. However, in this method, the transmission image capturing for specifying the examination location and the CT imaging are separate processes. Further, since the transmission image data and the CT imaging data for image reconstruction are different from each other, problems regarding the inspection time and the data capacity still remain.

  In particular, when pipe inspection is performed in a periodic inspection of a nuclear power plant, it is difficult to stop the plant for a long period of time. Therefore, it is required to shorten the time required for pipe inspection and improve inspection efficiency.

  Hereinafter, an embodiment of the present invention will be described using a pipe equipped with a heat insulating material installed in a power plant as an object.

  FIG. 2 shows a system diagram in one embodiment of the present invention. The system shown in this figure includes a radiation imaging apparatus 11 and a control arithmetic unit 12. The radiation imaging apparatus 11 includes a radiation source 1, a radiation detector 2, and a scanner device 3 that supports them. The scanner device 3 has a function of performing translational scanning in the major axis direction of the pipe 10 on which the heat insulating material 99 is mounted while maintaining the positional relationship between the radiation source 1 and the radiation detector 2. The radiation detector 2 of this embodiment uses a two-dimensional radiation detector. In addition, the control arithmetic unit 12 captures an image capturing device 20 that captures a plurality of transmission image data 51 photographed by the radiation detector 2, a control device 21 that controls the scanner device 3, the radiation source 1, and the radiation detector 2. A transmission image data storage device 31 that stores a plurality of transmission image data 51, and a plurality of transmission image data 51 are read from the transmission image data storage device 31 and displayed as still images or moving images on a monitor such as a PC. The image reconstructing device for reconstructing a tomographic image or a three-dimensional stereoscopic image of the subject based on the obtained image 22, a reconstructed image storage device 32 for storing a tomographic image or a three-dimensional stereoscopic image (reconstructed image) of the reconstructed subject. In consideration of user convenience, an image measurement device 23 equipped with image measurement software or the like for performing image measurement using a tomographic image or a three-dimensional stereoscopic image (reconstructed image) can be added as necessary. is there.

  FIG. 1 shows a flowchart of an inspection method according to the present invention. The inspection method of the present invention includes an imaging flow 2001 for acquiring transparent image data by imaging, and an image processing flow 2002 for determining whether image reconstruction is necessary and performing image reconstruction based on the acquired transparent image data. .

  In the imaging flow 2001, the scanner device 3 moves the radiation source 1 and the radiation detector 2 in the longitudinal direction of the pipe, and starts translational scanning (processing 2003). The radiation source 1 emits radiation at the current scanner position, and the radiation that has passed through the pipe enters the radiation detector 2 to capture a transmission image (processing 2004). The transmitted image data captured by the image capturing device 20 from the radiation detector 2 is stored in the transmitted image data storage device 31 (process 2005). Then, the control device 21 moves the scanner device 3 by a specified distance in the long axis direction of the pipe (process 2006), and determines whether the scanner apparatus 3 has reached the end of the pipe (process 2007). In process 2007, when the scanner device 3 has not reached the end of the pipe, the process returns to process 2004, and a transmission image at the current scanner position is captured. On the other hand, when the scanner device 3 reaches the end of the pipe, the photographing is finished (processing 2008).

  In the image processing flow 2002, the transparent image data stored in the transparent image data storage device 31 is read out and displayed on the screen of the determination device 24 as necessary (processing 2009). Based on the read transparent image data, it is determined whether image reconstruction is necessary, and the result is input to the determination device 24 (processing 2010). A specific example of the determination method will be described later. When a defect or the like is found in the inspection target and image reconstruction is necessary (process 2011), an instruction is issued to the image reconstruction device 22 to perform image reconstruction (process 2012). Details of the image reconstruction method will be described later. If the read transmission image data is at the end of the pipe (inspection target), the process ends. If not, the reading process 2009 is repeated (process 2013). If it is determined in step 2011 that image reconstruction is unnecessary, it is determined whether the transmitted image data is data at the end of the pipe (step 2013).

  In this flowchart, shooting and image processing are performed in parallel, but image processing may be performed after all shooting is completed.

  A specific example of the radiation imaging apparatus 11 which is one component of the present invention, and a tomographic image or a three-dimensional stereoscopic image (reconstructed image) of a subject from a plurality of transmission image data 51 captured by the radiation imaging apparatus 11 A generation method will be described.

  FIG. 3 shows specific examples of the radiation imaging apparatus 11 and the control calculation apparatus 12. In this specific example, the radiation source 1 and the radiation detector 2 are held by a C-shaped arm 3a, and the C-shaped arm 3a is scanned on a guide rail 3b. The guide rail 3b is arrange | positioned along the major axis direction of the piping 10 with which the heat insulating material (not shown) was mounted | worn by the support leg 3c installed on the floor surface. The C-shaped arm 3 a is formed along the outer peripheral surface of the pipe 10, and the radiation source 1 and the radiation detector 2 are arranged to face each other with the pipe 10 interposed therebetween.

  Each time the C-shaped arm 3a moves a certain distance in the long axis direction of the pipe, the radiation source 1 emits radiation to the pipe. Transmission image data 51 photographed by the radiation detector 2 while the C-shaped arm 3a is scanning the pipe is captured from the radiation detector 2 to the image capturing device 20 as needed. An example of the state of imaging by the radiation imaging apparatus 11 as shown in a specific example is shown in FIG. For simplicity, the scanner device 3 is omitted in FIG.

  FIG. 5 shows a collection range of transmission image data necessary for image reconstruction. For simplicity, the figure shows the case of two-dimensional imaging. In the case of three-dimensional imaging, this two-dimensional concept is expanded. Consider the case where the radiation source 1 and the radiation detector 2 perform translational scanning from the left to the right as shown in (a), (b), and (c) of the figure. Further, a plate-like object 10a is considered as a subject, and attention is paid to a point 10b inside the object 10a.

  The radiation 5 transmitted through the internal point 10b starts translational scanning in the direction shown in FIG. 5A, passes through the direction shown in FIG. 5B, and ends in the direction shown in FIG. 5C. If the opening angle of the radiation is θ, the angle range of the radiation 5 that passes through the internal point 10b during this translational scanning is also θ. Generally, in order to reconstruct a tomographic image by CT imaging, it is necessary to transmit radiation from a direction of 180 ° to 360 ° with respect to the subject. On the other hand, in the radiation imaging apparatus 11 of the present invention, the radiation transmission direction is an angle θ. This θ is determined by the radiation angle of the radiation source 1 or the size of the detection surface of the radiation detector 2 and is about 40 ° to 60 °. In order to perform image reconstruction under such conditions, a technique (Limited Angle image reconstruction) that performs image reconstruction in a state where the projection angle is limited is required.

  Many limited angle image reconstruction methods have been proposed. In the following, an image reconstruction method will be described using the Digital Tomosynthesis (DTS) method, which is one of the methods, as an example. Of course, other limited angle image reconstruction methods can be applied.

  FIG. 6 shows the principle of image reconstruction by the DTS method. For simplicity, consider the case where only the radiation source 1 is translated and the radiation detector 2 is fixed. The subjects are a circular subject 10c and a rectangular subject 10d having no thickness. It is assumed that the subject 10 c and the subject 10 d are arranged in parallel to the radiation detector 2 and perpendicular to the direction axis from the radiation source 1 toward the radiation detector 2. Further, it is assumed that the subject 10c and the subject 10d have different distances from the radiation source 1.

  For the subjects 10c and 10d, transmission image data 51 as shown in the figure is photographed corresponding to each position when the radiation source 1 performs translational scanning. When reconstructing a cross section including the circular subject 10c from these transmission image data 51, after moving each transmission image data 51 so that the projection part of the subject 10c in each transmission image data 51 overlaps, The transparent image data 51 is superimposed. By this processing, a circular image becomes clear. The amount of movement of each transmission image data 51 includes the amount of movement of the radiation source 1 during imaging of each transmission image data 51, the distance between the radiation source 1 and the cross section including the circular subject 10c, and the circular subject 10c. It is determined by the distance between the included cross section and the radiation detector 2. Further, the projection portion of the subject 10d in each transmission image data 51 becomes a blurred image by the movement and overlay processing of the transmission image data 51. As a result, a contrast difference occurs between the circular subject 10c and the rectangular subject 10d, and a tomographic image 52 that is a reconstructed image of the subject 10c can be generated.

  The subject 10d located at a different depth from the subject 10c with respect to the radiation source 1 can also generate a reconstructed image by the same method as the above-described reconstruction method.

  As described above, since a tomographic image or a three-dimensional image of a pipe can be reconstructed using a transmission image of the pipe photographed for screening the pipe, it is not necessary to re-acquire data. Therefore, the inspection time can be shortened and the inspection efficiency can be improved.

  FIG. 7 shows an example in which a limited angle reconstruction image technique such as the radiation imaging apparatus 11 and the DTS method is applied to pipe imaging. In this case, the reconstructed image 52 is generated as a cross section having a normal vector parallel to the axis from the radiation source 1 toward the radiation detector 2 as shown in the figure. Further, a plurality of reconstructed images 52 having different distances from the radiation source 1 are generated between the radiation source 1 and the radiation detector 2. A three-dimensional stereoscopic image 53 can be constructed by stacking the reconstructed images 52 in the axial direction from the radiation source 1 toward the radiation detector 2.

  FIG. 8 shows a processing flow of image reconstruction (processing 2012 in FIG. 1). First, a condition input process 1001 for inputting calculation conditions such as input data names and calculation parameters is executed. Next, based on the input calculation conditions, the image reconstruction device 22 reads the transmission image data 51 and the air data 52 captured by the radiation imaging device 11 from the transmission image data storage device 31 respectively, and transmits the transmission image data reading processing 1002. The air data reading process 1003 is executed. In the transmission image data reading process 1002 and the air data reading process 1003, first transmission image data obtained by photographing a part of a pipe that requires image reconstruction in order to check the state of a defective part of the pipe, The second transparent image data photographed before and after the transparent image data is read. The air data is data taken in the absence of the subject, and is obtained with radiation intensity without attenuation. This data is used in the next processing.

  Next, logarithmic conversion processing 1004 is executed. The logarithmic conversion process is a process of logarithmically converting the ratio between the radiation intensity without attenuation and the radiation intensity transmitted through the subject and attenuated, and is represented by (Equation 1).

Here, I ou, v is the radiation intensity without attenuation detected by the radiation detection element at the position (u, v) on the radiation detector 12, and I u, v is radiation with attenuation detected at the same position. Represents strength. Further, μ represents a linear attenuation coefficient depending on the material and radiation energy, and t represents a radiation transmission path. Image reconstruction is a process for obtaining the spatial distribution of μ using the left side of (Equation 1) as an input value. Subsequently, preprocessing 1005 is executed. In the pre-processing 1005, a correction for an element having a variation or a defect among a large number of detection elements, a correction depending on an apparatus, and the like are performed. This pre-processing 1005 may be performed before the logarithmic conversion processing 1004 according to circumstances.

  After the above processing, back projection operation processing 1006 is executed. The backprojection calculation process is a process of mapping (backprojecting) data corrected and converted so far into a two-dimensional or three-dimensional space. The DTS method described above corresponds to the movement and overlay processing of transparent image data. By this back projection operation, a two-dimensional tomographic image or a three-dimensional stereoscopic image (reconstructed image) is finally generated.

  By using the radiation imaging apparatus 11 and the limited angle image reconstruction method described above, it is possible to reconstruct an image without acquiring again the data for image reconstruction calculation from the once-transmitted transmission image data.

  In addition, the use of the radiation imaging apparatus 11 and the Limited Angle image reconstruction method makes it possible to obtain a tomographic image and a three-dimensional image of the pipe. Therefore, the position and amount of pipe thinning are more accurate than those of conventional RT. It can be detected well. Even if the length of the pipe to be inspected reaches several meters, it is possible to take a picture in a short time. Furthermore, since it is possible to take an image with the heat insulating material attached to the pipe as in the case of RT, the step of detaching the heat insulating material can be omitted at the start and end of the inspection, so that the inspection efficiency can be improved.

  Next, the image processing flow 2002 of FIG. 1 will be described in detail with reference to FIG. In this inspection flow, the determination device 24 determines whether or not image reconstruction is necessary for each part of the subject, and limits the region in which the three-dimensional stereoscopic image of the pipe is reconstructed.

  First, the determination device 24 reads a plurality of transmission image data 51 from the transmission image data storage device 31 (processing 1101). The plurality of read transparent image data 51 is displayed on the screen of the determination device 24 (processing 1102). The plurality of transmission image data 51 are displayed as a still image or a moving image on the screen. The operator visually confirms the plurality of displayed transmission image data 51 and determines whether or not it is necessary to reconstruct a three-dimensional image of the pipe in order to observe the three-dimensional shape of the pipe (processing 1103 to 1104). The determination as to whether reconfiguration is necessary may be executed based on an operator's judgment criteria, or some criteria may be determined in advance using a standard document, and may be executed based on the criteria. When it is necessary to reconstruct a three-dimensional image (or a two-dimensional cross-sectional image), the image is reconstructed via the input device included in the determination device 24 on the plurality of transmission image data 51 displayed on the screen. An area is designated (process 1105), and an instruction to execute image reconstruction is issued to the image reconstruction device 22 (processes 1106 to 1107). This is executed up to the end of scanning (process 1108). If it is not necessary to reconstruct the image, the process proceeds to process 1108 to continue the process.

  10 and 11 show an example of a screen in which a plurality of transmission image data is displayed on the screen of the determination device 24. FIG. In this figure, when the transparent image reading button 60 is pressed, the transparent image data is read from the transparent image data storage device 31 and a plurality of transparent image data 51 is displayed on the screen as a moving image. As shown in FIG. 6, the transmission image data 51 is an image in which the subjects 10c and 10d positioned between the radiation source 1 and the radiation detector 2 are overlapped in the depth direction. Therefore, it is possible to display the thinned portion 63 of the pipe by the grayscale display in the transmission image data 51 without reconstructing the two-dimensional image or the three-dimensional image of the pipe. In addition, since the area where the two-dimensional image or the three-dimensional image is reconstructed can be narrowed down by screening the location of the pipe where the defect such as thinning occurs with the transmission image, the calculation amount of the image reconstruction is reduced. Is possible. Furthermore, since it is not necessary to reconstruct the entire length of the pipe, it is possible to reduce the storage capacity of the reconstructed image storage device that stores a two-dimensional image or a three-dimensional image. Therefore, the inspection efficiency of piping can be improved.

  When the operator confirms the transmission image data 51 and finds the thinned portion 63 of the pipe, the operator presses the button 61 for stopping the moving image to confirm the thinned portion 63 in the three-dimensional image of the pipe. Then, a determination result is input by pressing a button 62 for determining whether image reconstruction is necessary.

  If it is determined that image reconstruction is necessary, the screen transitions to FIG. On this screen, the reconstruction area 65 is designated by the pointer 64 using an input device such as a mouse connected to the PC, and the button 66 is pressed to execute the calculation. By depressing the button 66, a command for image reconstruction is issued to the image reconstruction device 22. When the reconstruction area 65 is designated, it may be designated by a rectangle so as to surround the pipe thinning portion 63.

  FIG. 12 shows the result of displaying a two-dimensional tomographic image or a three-dimensional stereoscopic image on the screen for the piping portion corresponding to the reconstruction area 65 of the transmission image. By reconstructing a two-dimensional tomographic image or a three-dimensional stereoscopic image, the three-dimensional shape of the pipe thinning portion 63 can be easily confirmed. In this way, by confirming only a portion suspected of a defect such as thinning of the pipe in the transmission image data with a two-dimensional tomographic image or a three-dimensional stereoscopic image, a two-dimensional tomographic image or a three-dimensional stereoscopic image is obtained over the entire length of the pipe. There is no need to reconfigure, the inspection time can be greatly shortened, and the inspection efficiency can be improved. In addition, it is possible to reduce the storage capacity of the reconstructed image storage device by limiting the generation of a reconstructed image having a large data capacity to a part of the piping.

  In addition to the area designation by the input device, there is a method for automatically designating the reconstruction area based on calculation conditions (FIG. 13). FIG. 13 shows an example of the range of transparent image data used for image reconstruction. In FIG. 13, the length 1 (mm) of the transmission image data 51a in the scanning direction, the movement of the radiation source 1 and the radiation detector 2 is determined based on the first transmission image data 51a determined to require image reconstruction. A method of determining the range of transmission image data used for image reconstruction from the speed v (mm / sec) and the imaging speed of the radiation detector 2 (number of images to be captured per second) f (frame / sec) is considered. It is done. Here, the first transmission image data 51a determined to require image reconstruction is the central portion of FIG. 13, and the number of second transmission image data to be used before and after (51b, 51c) is expressed by 2).

  If it is determined that image reconstruction is not necessary, the screen of FIG. 11 is not transitioned and the moving image display is resumed.

  In the case of a pipe inspection in a power plant or the like, the purpose of searching for a thinning state of a pipe pipe wall or a foreign substance mixed in the pipe is considered. At this time, in the transmission image data, since all the information on the photographing direction is displayed in an overlapping manner, it is often difficult to identify the initial stage of thinning or small foreign matter. Therefore, confirm the multiple transmission image data displayed on the screen, determine that it is necessary to reconstruct the image that seems to be suspicious, reconstruct the tomographic image or stereoscopic image, and more in detail. Operation such as inspection is desirable.

  FIG. 14 shows a system diagram in another embodiment of the present invention. In the system shown in this figure, instead of the determination device 24 in FIG. 2, as reference data input means for inputting reference data for supporting necessity determination, the material of the subject or the linear attenuation coefficient μ, the subject's An input device 26 for inputting dimensions and a storage device 27 storing an attenuation amount calculation program 28 are provided.

  FIG. 15 shows a processing flow of this embodiment. In this flow, processing 1201 and processing 1202 are added before processing 1101 with respect to the image processing flow of the first embodiment (FIG. 9), processing 1203 is added instead of processing 1102 and 1103, and the determination condition is processing 1204. It has become.

The process 1201 is a process for inputting the material of the subject or the attenuation coefficient μ and the size of the subject with the input device 26. Process 1202 is a process of calculating by (Equation 3) and the radiation intensity I r of the attenuation amount calculation program 28 when transmitted through the object from the input processing 1201.

Here, I o represents the radiation intensity when there is no attenuation, and t represents the length of transmission of the radiation through the subject. t uses the dimension of the subject input in the process 1201. When the material is input in the process 1201, the attenuation coefficient database corresponding to the material stored in advance in the storage device 27 is referred to and converted into a value of μ.

In process 1203, the data comparing means for comparing the transmitted image data stored with the reference data to the transmission image data storage device, the radiation intensity I for each pixel of I r and the transmission image calculated in process 1202 Compare In order to compare I r according to (Equation 3) with I at each pixel of the transmission image, it is necessary to consider the device geometry and calculate it corresponding to each pixel position of the transmission image.

  As a difference determination means for determining the presence or absence of an arbitrary difference based on the comparison result, the determination condition by the processing 1204 uses a threshold value set in advance by the operator based on experience or the like, and when this value is exceeded, image reconstruction is performed. Shall be implemented.

  The process 1105 can use the method described in the first embodiment.

  As described above, by using the determination condition based on the process 1204, it is possible to accurately determine a defective portion of a pipe that is difficult to find visually.

  According to the present embodiment, when the object shape is simple such as a cube or a cylinder, the transmission length t can be obtained by geometric calculation, so that the processing can be simplified and speeded up.

  FIG. 16 shows a system diagram in another embodiment of the present invention. In the system shown in this figure, instead of the input device 26 and the storage device 27 of FIG. 14, a calculation device 29 that performs simulation using CAD data of the subject, and a memory that stores the CAD data and simulation program of the subject. A device 30 is installed.

  FIG. 17 shows a processing flow of this embodiment. In this image processing flow in the second embodiment, processes 1301 to 1303 are substituted for the processes 1201 and 1202, and processes 1304 and 1305 are substituted for the processes 1203 and 1204.

  A process 1301 is a process for inputting the CAD data of the subject to the storage device 30. A process 1302 is a process of inputting the material or attenuation coefficient of the subject to the storage device 30. The process 1303 performs a simulation of simulating the transmission of radiation by calculation using the arithmetic unit 29 using the input data and values. The arithmetic unit 29 is a process for calculating the transmission image data in the CAD data.

FIG. 18 is a diagram showing an outline of simulation using CAD data by the arithmetic unit 29 in the processing 1303. For the sake of simplicity, a two-dimensional simulation is shown for the cross section of the CAD data 81 indicated by a dotted line. The cross-sectional image of the CAD data 81 is generated as a two-dimensional bitmap image 71 by rasterization processing or the like. As shown in the enlarged view on the right side of the figure, the bitmap image is divided by a small square lattice. In the simulation, the length when the radiation transmission path 5a connecting the radiation emission point of the radiation source 1 and each element of the radiation detector 2 crosses each grid of the bitmap image 71 and the value of μ corresponding to the pixel value in each grid. Find the product of. The product values in each grid are added over all grids traversed by the radiation transmission path 5a. Radiation intensity I s at each element of the radiation detector 2 calculated by the simulation can be calculated by (Equation 4).

Here, Io represents the radiation intensity when there is no attenuation. μ i represents a linear attenuation coefficient in the i-th grating traversed by the radiation transmission path 5a, and t i represents a length passing through the grating.

  On the other hand, in processing 1101, the radiation detector 2 reads transmission image data obtained by imaging the pipe from the transmission image data storage device 31.

  In processes 1304 and 1305, the transmission image data obtained by imaging the pipe and the transmission image data obtained from the CAD data simulation are compared to determine whether or not image reconstruction is necessary. The subsequent processing procedure is the same as in the second embodiment.

  According to the present embodiment, since a bitmap image made from CAD data can be used as an input, even if simple geometric calculation is difficult due to complicated shapes such as piping valves and socket elbows, Processing is possible. Further, even when the same product or the same lot product described in the following embodiments cannot be used, processing is possible.

  FIG. 19 shows a system diagram in another embodiment of the present invention. In the system shown in this figure, instead of the arithmetic device 29 and the storage device 30 of FIG. 16, an arithmetic device 41 that compares and calculates transmission image data, and a storage device 42 that stores a plurality of transmission image data photographed in advance. It is installed.

  FIG. 20 shows a processing flow of this embodiment. This flow is processing 1401 instead of processing 1301 to 1303 in the inspection flow of FIG. In the process 1401, the same product or the same lot product is imaged in advance by the radiation imaging apparatus 11 prior to the inspection by this system, and a plurality of obtained transmission image data (P) 51 is stored in the storage device 42. It is processing. Further, the processes 1402 and 1403 are the same in concept as the processes 1304 and 1305 of FIG. 17, respectively, and only the data used for comparison is different.

  In processing 1101, the arithmetic device 41 reads the transmission image data (R) taken at the time of inspection from the transmission image data storage device 31.

  In processing 1402 and processing 1403, the computing device 41 compares the transmission image data (P) of the same product or the same lot product captured in advance with the transmission image data (R) captured at the time of inspection. As a result of the comparison, when the difference in data exceeds a certain threshold, image reconstruction is performed. In this determination method, determination based on an actual product is possible. It is also possible to capture changes in the subject over time by photographing the same product.

  According to the above embodiment, since the transmission image for screening for searching for a defective portion of the pipe with the transmission image and the data necessary for reconstructing the tomographic image or the three-dimensional stereoscopic image are the same, There is no need to re-take, the inspection time can be shortened, and the inspection efficiency can be improved.

  Further, since the area to which image reconstruction is applied can be narrowed down by screening using a transmission image, it is not necessary to reconstruct the image over the entire length of the pipe. Therefore, the amount of calculation for reconstructing the image can be reduced, and the inspection efficiency can be improved.

  Further, since the area to which image reconstruction is applied can be narrowed down by screening using a transmission image, the amount of data associated with the generation of a tomographic image or a three-dimensional stereoscopic image can be reduced, and inspection efficiency can be improved. .

  According to this embodiment, the following effects are obtained. In the case of the same product, since the shape error is not included except for the defective part, it is possible to capture the change only in the defective part with high accuracy. In the case of the same lot product, since the shape error between the same lot products is small, even if the same product cannot be used, it is possible to accurately identify the defective portion. Even if CAD data does not exist, processing is possible.

  By using the system of the present invention, not only piping installed in a power plant but also large structures such as aircraft wings can be efficiently inspected by radiation.

It is a flowchart of the whole inspection method in the present invention. It is a system diagram showing a radiation nondestructive inspection system. (Example 1) It is a specific example of the radiography apparatus used with a radiation nondestructive inspection system. It is a figure explaining the mode of imaging | photography with a radiography apparatus. It is a figure explaining the collection range of the transmission image used by the image reconstruction calculation of a radiation nondestructive inspection system. It is the figure explaining the principle of the image reconstruction about an example of the image reconstruction method. It is a figure explaining the example which applied the radiography apparatus and image reconstruction to piping. It is a flowchart of an image reconstruction calculation process. FIG. 3 is an inspection flowchart of the first embodiment. It is a figure explaining the example of a display of a transmissive image. It is the figure which designated the reconstruction area in the transmission image. It is a figure explaining the example of a display of an image reconstruction calculation result. It is a figure explaining an example of the method of determining automatically the range of the permeation | transmission image used for image reconstruction calculation. It is a system diagram showing a radiation nondestructive inspection system. (Example 2) FIG. 6 is an inspection flow diagram of Example 2. It is a system diagram showing a radiation nondestructive inspection system. (Example 3) FIG. 6 is an inspection flow diagram of Example 3. It is a figure explaining the simulation using CAD data. It is a system diagram showing a radiation nondestructive inspection system. (Example 4) FIG. 10 is an inspection flow diagram of Example 4.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Radiation source 2 Radiation detector 3 Scanner apparatus 3a C-shaped arm 3b Guide rail 3c Support leg 5 Radiation 10 Piping 10a Object 10c, 10d Subject 11 Radiography apparatus 12 Control arithmetic unit 22 Image reconstruction apparatus 23 Image measurement apparatus 24 Determination device 26 Input device 27 Storage device 28 Attenuation amount calculation program 29, 41 Arithmetic device 30, 42 Storage device 31 Storage device 51 Transmission image data 52 Reconstructed image 53 Three-dimensional stereoscopic image 71 Bit map image 81 CAD data 99 Insulating material 1001 ~ 1403 treatment

Claims (10)

  1. A radiation source and a radiation detector arranged opposite to each other with the subject to be examined interposed therebetween;
    A radiographic apparatus that translates the radiation source and the radiation detector along the subject; and
    A radiation nondestructive inspection system including a control arithmetic unit that acquires transmission image data obtained by the radiation imaging apparatus,
    The control arithmetic unit is
    An image capturing device for capturing the transparent image data;
    A control device for controlling the position of the radiation imaging apparatus;
    A transmission image data storage device for storing the transmission image data transmitted from the image capture device;
    A determination device for determining a portion of the subject that requires image reconstruction based on the transmission image data from the transmission image data storage device;
    A radiation nondestructive inspection system comprising an image reconstruction device for reconstructing a tomographic image or a three-dimensional stereoscopic image of the subject based on the transmission image data.
  2. A radiation source for irradiating the subject with radiation;
    A radiation detector provided on the opposite side of the radiation source across the subject;
    A radiation imaging apparatus that translates the radiation source and the radiation detector;
    A radiation nondestructive inspection system including a control arithmetic device that acquires transmission image data output by the radiation detector,
    The control arithmetic unit is
    An image capturing device for capturing the transmitted image data output from the radiation detector;
    A control device for controlling the position of the radiation imaging apparatus;
    A transmission image data storage device for storing the transmission image data captured by the image capture device;
    A determination device that identifies a portion of the subject that requires image reconstruction based on the transmission image data from the transmission image data storage device;
    A radiation nondestructive inspection system comprising an image reconstruction device for reconstructing a tomographic image or a three-dimensional stereoscopic image of the subject based on the transmission image data with respect to a portion of the subject identified by the determination device.
  3. A radiation source and a two-dimensional radiation detector which are moved on a guide rail installed along the longitudinal direction of the pipe to be inspected, and which are arranged to face each other across the pipe;
    A C-shaped arm for fixing the radiation source and the two-dimensional radiation detector to translate the radiation source and the two-dimensional radiation detector along the pipe;
    A radiation nondestructive inspection system comprising a control arithmetic unit that acquires transmission image data from the two-dimensional radiation detector for every fixed distance that the C-shaped arm moves,
    The control arithmetic unit is
    An image capturing device for capturing the transmission image data output from the two-dimensional radiation detector;
    A control device for controlling the position of the C-shaped arm;
    A transmission image data storage device for storing the transmission image data captured by the image capture device;
    A determination device that identifies a portion of the subject that requires image reconstruction based on the transmission image data from the transmission image data storage device;
    Based on the first transmission image data corresponding to the part of the subject specified by the determination device and the second transmission image data photographed before and after the first transmission image data, the tomographic image of the subject or three-dimensional A radiation nondestructive inspection system comprising an image reconstruction device for reconstructing a stereoscopic image.
  4. The radiation nondestructive inspection system according to claim 1,
    The determination device compares the first radiation intensity calculated from the attenuation coefficient and size of the subject with the second radiation intensity at each pixel of the transmission image stored in the transmission image data storage device. A radiation nondestructive inspection system characterized by judging.
  5. The radiation nondestructive inspection system according to claim 1,
    The determination device compares the first radiation intensity calculated based on the CAD data of the subject and the second radiation intensity at each pixel of the transmission image stored in the transmission image data storage device. A radiation nondestructive inspection system characterized by judging.
  6. The radiation nondestructive inspection system according to claim 1,
    The determination apparatus includes a first radiation intensity obtained from the same product or the same lot product of the subject and a second radiation intensity at each pixel of the transmission image stored in the transmission image data storage device. A radiation nondestructive inspection system characterized by making a comparison.
  7. The radiation nondestructive inspection system according to claim 1,
    The radiological nondestructive inspection system according to claim 1, further comprising an input unit that designates a spatial region in which the tomographic image or the stereoscopic image is reconstructed from the transmission image data.
  8. The radiation nondestructive inspection system according to claim 1,
    The determination device includes reference data input means for inputting reference data for supporting necessity determination, and data comparison for comparing the reference data with the transmission image data stored in the transmission image data storage device. A radiation nondestructive inspection system comprising: means; and a difference determining means for determining the presence or absence of an arbitrary difference based on the comparison result.
  9. A first step of translationally scanning the radiation source and the radiation detector along the longitudinal direction of the pipe to obtain a plurality of pieces of transmission image data of the pipe;
    A second step of determining a portion of the pipe that reconstructs a tomographic image or a three-dimensional image of the pipe based on a plurality of the transmission image data;
    A pipe inspection method comprising: a third step of reconstructing a tomographic image or a three-dimensional image of the pipe based on the transmission image data for the determined part of the pipe, and inspecting the state of the pipe.
  10. A first step of translationally scanning the radiation source and the radiation detector along the longitudinal direction of the pipe to obtain a plurality of pieces of transmission image data of the pipe;
    A second step of determining a portion of the pipe that reconstructs a tomographic image or a three-dimensional image of the pipe based on a plurality of the transmission image data;
    Based on the first transmission image data corresponding to the determined part of the subject and the second transmission image data taken before and after the first transmission image data, a tomographic image or a three-dimensional stereoscopic image of the subject is reproduced. A pipe inspection method comprising: a third step of configuring and inspecting the state of the pipe.
JP2007250402A 2007-09-27 2007-09-27 Radiation nondestructive inspection system and piping inspection method Expired - Fee Related JP4595979B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2007250402A JP4595979B2 (en) 2007-09-27 2007-09-27 Radiation nondestructive inspection system and piping inspection method

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP2007250402A JP4595979B2 (en) 2007-09-27 2007-09-27 Radiation nondestructive inspection system and piping inspection method
EP20080007770 EP1985998A1 (en) 2007-04-26 2008-04-22 Method for inspecting pipes, and radiographic non-destructive inspection apparatus
US12/108,183 US7885381B2 (en) 2007-04-26 2008-04-23 Method for inspecting pipes, and radiographic non-destructive inspection apparatus

Publications (2)

Publication Number Publication Date
JP2009080055A true JP2009080055A (en) 2009-04-16
JP4595979B2 JP4595979B2 (en) 2010-12-08

Family

ID=40654902

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2007250402A Expired - Fee Related JP4595979B2 (en) 2007-09-27 2007-09-27 Radiation nondestructive inspection system and piping inspection method

Country Status (1)

Country Link
JP (1) JP4595979B2 (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010074031A1 (en) * 2008-12-22 2010-07-01 オムロン株式会社 X-ray inspection method and x-ray inspection apparatus
JP2011052968A (en) * 2009-08-31 2011-03-17 Hitachi-Ge Nuclear Energy Ltd Piping tomograph and method of controlling the same
JP2011058983A (en) * 2009-09-11 2011-03-24 Hitachi Ltd Method for photographing of radiation tomograph
JP2011209089A (en) * 2010-03-30 2011-10-20 Hitachi Ltd Radiation tomographic method and radiation tomographic apparatus
JP2013205267A (en) * 2012-03-29 2013-10-07 Hitachi-Ge Nuclear Energy Ltd X-ray tomographic method and x-ray tomographic apparatus
JP2014062743A (en) * 2012-09-20 2014-04-10 Hitachi Ltd X-ray tomographic method and x-ray tomographic apparatus

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5425190A (en) * 1977-07-28 1979-02-24 Yoshinori Hayakawa Desired section transmission computer tomography
JPS60179853U (en) * 1984-05-03 1985-11-29
JPH03100405A (en) * 1989-09-13 1991-04-25 Hitachi Ltd Computer tomograph
JPH09304303A (en) * 1996-05-15 1997-11-28 Hitachi Eng & Services Co Ltd Portable x-ray ct device
JPH11194101A (en) * 1998-01-06 1999-07-21 Hitachi Eng & Service Co Ltd Ct imaging apparatus for piping and monitoring method for deposition of silicon oxide
JP2001004562A (en) * 1999-06-22 2001-01-12 Cxr:Kk Piping corrosion inspecting device
JP2001324456A (en) * 2000-05-17 2001-11-22 Shimadzu Corp X-ray cross-sectional plane examination apparatus
JP2003202304A (en) * 2001-12-28 2003-07-18 Toshiba Corp Radiation nondestructive inspecting apparatus and method
JP2004108990A (en) * 2002-09-19 2004-04-08 Toshiba It & Control Systems Corp Laminograph with filtering

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5425190A (en) * 1977-07-28 1979-02-24 Yoshinori Hayakawa Desired section transmission computer tomography
JPS60179853U (en) * 1984-05-03 1985-11-29
JPH03100405A (en) * 1989-09-13 1991-04-25 Hitachi Ltd Computer tomograph
JPH09304303A (en) * 1996-05-15 1997-11-28 Hitachi Eng & Services Co Ltd Portable x-ray ct device
JPH11194101A (en) * 1998-01-06 1999-07-21 Hitachi Eng & Service Co Ltd Ct imaging apparatus for piping and monitoring method for deposition of silicon oxide
JP2001004562A (en) * 1999-06-22 2001-01-12 Cxr:Kk Piping corrosion inspecting device
JP2001324456A (en) * 2000-05-17 2001-11-22 Shimadzu Corp X-ray cross-sectional plane examination apparatus
JP2003202304A (en) * 2001-12-28 2003-07-18 Toshiba Corp Radiation nondestructive inspecting apparatus and method
JP2004108990A (en) * 2002-09-19 2004-04-08 Toshiba It & Control Systems Corp Laminograph with filtering

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010074031A1 (en) * 2008-12-22 2010-07-01 オムロン株式会社 X-ray inspection method and x-ray inspection apparatus
JP2011052968A (en) * 2009-08-31 2011-03-17 Hitachi-Ge Nuclear Energy Ltd Piping tomograph and method of controlling the same
JP2011058983A (en) * 2009-09-11 2011-03-24 Hitachi Ltd Method for photographing of radiation tomograph
JP2011209089A (en) * 2010-03-30 2011-10-20 Hitachi Ltd Radiation tomographic method and radiation tomographic apparatus
JP2013205267A (en) * 2012-03-29 2013-10-07 Hitachi-Ge Nuclear Energy Ltd X-ray tomographic method and x-ray tomographic apparatus
JP2014062743A (en) * 2012-09-20 2014-04-10 Hitachi Ltd X-ray tomographic method and x-ray tomographic apparatus

Also Published As

Publication number Publication date
JP4595979B2 (en) 2010-12-08

Similar Documents

Publication Publication Date Title
US9795350B2 (en) Material differentiation with phase contrast imaging
JP2017500160A (en) Large-field phase contrast imaging method based on detuning configuration including acquisition and reconstruction techniques
US8879814B2 (en) Method and apparatus for reducing motion related imaging artifacts using consistency values
Bevins et al. Multicontrast x‐ray computed tomography imaging using Talbot‐Lau interferometry without phase stepping
JP5143333B2 (en) System and method for performing image processing for observing abnormal parts in different types of images
US4920491A (en) Enhancement of image quality by utilization of a priori information
CN100496402C (en) Image processing method, image processing system, and X-ray CT system
TWI259411B (en) Computed tomography
US7372937B2 (en) Systems and methods of non-standard spiral cone-beam computed tomograpy (CT)
JP5127248B2 (en) X-ray device focus-detector device
US7424089B2 (en) System and method for reconstructing image by using straight-line trajectory scan
JP5942266B2 (en) X-ray CT apparatus and tube current determination method
US6504892B1 (en) System and method for cone beam volume computed tomography using circle-plus-multiple-arc orbit
Zhu et al. Cone beam micro-CT system for small animal imaging and performance evaluation
US7778383B2 (en) Effective dual-energy x-ray attenuation measurement
CN105784731B (en) Mesh calibration method and safe examination system in a kind of positioning three-dimensional CT image
JP4079632B2 (en) Method and apparatus for selecting and displaying medical image data
US6341153B1 (en) System and method for portable nondestructive examination with realtime three-dimensional tomography
US10481110B2 (en) Radiographic image generating device
US6850586B2 (en) Method and system for reconstructing an image from projection data acquired by a cone beam computed tomography system
US7015473B2 (en) Method and apparatus for internal feature reconstruction
CN1957847B (en) Method and tomography unit for the reconstruction of a tomographic representation of an object
EP1325471B1 (en) Method and device for representing an object by means of an irradiation, and for reconstructing said object
US20050041775A1 (en) High speed digital radiographic inspection of piping
DE10347971B3 (en) Method and device for determining the liquid type of a liquid accumulation in an object

Legal Events

Date Code Title Description
A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20090526

A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20090910

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20090929

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20091127

A02 Decision of refusal

Free format text: JAPANESE INTERMEDIATE CODE: A02

Effective date: 20100302

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20100602

A911 Transfer of reconsideration by examiner before appeal (zenchi)

Free format text: JAPANESE INTERMEDIATE CODE: A911

Effective date: 20100712

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20100824

A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20100906

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20131001

Year of fee payment: 3

LAPS Cancellation because of no payment of annual fees