JP2019124580A - Radiation inspection device - Google Patents

Abstract

To provide a radiation inspection device which allows a user to recognize an end of life time frame in advance.SOLUTION: A radiation inspection device comprises a radiation source 2, a detector 3, a stage 4 on which a target object can be mounted, a movement mechanism for moving the stage, and a controller 5 configured to control at least the movement mechanism. The controller measures quality of the detector using a transmission image captured in accordance with imaging conditions 55a. A result of the measurement is stored as quality information in association with time information. A limit value 55b for the quality information is also stored. The controller analyzes temporal change in the quality information, computes an end of life time frame, at which the quality information reaches the limit value, on the basis of the temporal change in the quality information, and notifies the end of life time frame.SELECTED DRAWING: Figure 3

Description

  Embodiments of the present invention relate to a radiation inspection apparatus that detects radiation transmitted through a subject to form an image of the subject.

  A radiation inspection apparatus performing nondestructive inspection of a subject by detecting and imaging a two-dimensional distribution of radiation attenuated by irradiating the subject with radiation represented by X-rays and transmitting the subject. Are known. For example, the radiation inspection apparatus can find a void present inside a subject.

  This radiation inspection apparatus has a radiation source and a detector facing each other with a stage for mounting a subject interposed therebetween. The radiation source emits a radiation beam, and the detector transmits a subject to detect a two-dimensional distribution of the intensity of the attenuated radiation. As a detector, a combination of an image intensifier (I.I.) and a television camera, a flat panel detector (FPD), etc. are known.

  With this detector, sensitivity deterioration and printing occur with long-term use, and even if radiation of the same energy spectrum and dose rate is irradiated, the overall and partial brightness of the transmitted image changes. Since the degree of progress of deterioration varies depending on the inspection content, the replacement time is not definite, and in some cases, the inspection may be continued in a very poor state.

  Therefore, a radiation inspection apparatus capable of diagnosing the lifetime of a detector has been proposed (see, for example, Patent Document 1). The first transmission image at the beginning of use and the second transmission image after an arbitrary period have been taken under the same conditions, and at the beginning of use, the third transmission image is taken under conditions different from the first transmission image. A limit value is obtained from the difference in brightness between the first and third transmission images, and it is determined whether the difference in brightness between the first and second transmission images is within or outside the limit value.

Patent No. 3989777

  According to the method of determining whether the difference in luminance occurring in the transmission image at the beginning of use and after an arbitrary period has passed is within the limit value, it can be confirmed whether the detector has reached the end of its life. However, according to this determination method, unless the user of the radiation inspection apparatus actively and periodically executes the determination method, the end of the life can not be determined, and in the worst case, the inspection is detected rather than continuing in a poor state. There is a risk of the vessel dying suddenly. Also, even if the end of life is informed, it can not be replaced quickly.

  In order to solve the above-mentioned subject, this embodiment aims at providing a radiation inspection apparatus which can recognize beforehand a user's end of life end timing.

  In order to achieve the above object, the radiation inspection apparatus according to the present embodiment includes a radiation source for emitting radiation, a detector for detecting radiation, and an object between the radiation source and the detector. And a control unit configured to control the radiation source, the detector, and the stage according to a predetermined imaging condition by shifting to a quality diagnosis mode at a predetermined timing. The control unit is a measurement unit that measures the quality of the detector based on the transmission image captured according to the imaging condition, and a first storage unit that associates the measurement result of the measurement unit as quality information with time information and accumulates it. A second storage unit for storing the limit value of the quality information, and analyzing a temporal change of the quality information, and a life reaching timing at which the quality information reaches the limit value based on the temporal change It has a calculator for calculating, and a notification unit that notifies the life end timing, characterized by.

  The predetermined timing is a periodic timing after activation of the radiation inspection apparatus or during activation. The quality information includes an average luminance value of all pixels in a transmission image or pixels in a predetermined range, a luminance value of a predetermined pixel in the transmission image, a count number of pixels exceeding a predetermined luminance value, and a count number of pixels below a predetermined luminance value. Or a luminance difference of two or more pixels. The notification is screen display, e-mail transmission, storage that can be read out, and the like.

It is a block diagram which shows an example of a structure of a radiation inspection apparatus. It is a flowchart which shows operation | movement of a control part. It is a block diagram showing composition of a control part. It is a flowchart which shows operation | movement of the quality diagnostic part which concerns on 1st Embodiment. It is a graph of the approximation formula which shows the relationship between a luminance value and a period. It is a schematic diagram which shows the screen of quality diagnosis mode. It is a block diagram which shows the structure of a quality diagnostic part. It is a block diagram which shows the other example of a structure of a radiation inspection apparatus. I. I. It is a schematic diagram which shows the quality degradation of. It is a schematic diagram which shows the quality fall of FPD. It is a flowchart which shows operation | movement of the quality diagnostic part which concerns on 2nd Embodiment. It is a graph of the approximation formula which shows the relationship between the count value of a pixel below a predetermined luminance value, and a period. It is a flowchart which shows operation | movement of the quality diagnostic part which concerns on the modification 1 of 2nd Embodiment. It is a graph of the approximation formula which shows the relationship between the count value of a pixel more than predetermined luminance value, and a period. It is a schematic diagram which shows the central area of an imaging visual field. It is a flowchart which shows operation | movement of the quality diagnostic part which concerns on the modification 2 of 2nd Embodiment. It is a schematic diagram which shows the level | step-difference body which concerns on 3rd Embodiment. It is a graph which shows the imaging result of a level | step-difference body. It is a flowchart which shows operation | movement of the quality diagnostic part which concerns on 3rd Embodiment. It is a flowchart which shows operation | movement of the quality diagnostic part which concerns on the modification of 3rd Embodiment. It is a flow chart which shows quality diagnostic mode in a case of storing a plurality of kinds of photography conditions. It is a schematic diagram which shows the other example of the screen of quality diagnostic mode. It is a block diagram which shows the other structure of a quality diagnostic part. It is a flow chart which shows operation of calculation of end-of-life timing in the case of having standard end-of-life end timing.

First Embodiment
Hereinafter, the radiation inspection apparatus according to the first embodiment will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration example of a radiation inspection apparatus. As shown in FIG. 1, the radiation inspection apparatus 1 irradiates radiation to the subject 100, detects radiation transmitted through the subject 100, and forms an image of the inside of the subject according to the detection result. The image in the subject 100 is a fluoroscopic image, a tomographic image or a 3D image. That is, the radiation inspection apparatus 1 includes a fluoroscope and a CT apparatus that reconstructs a tomogram of the subject 100 from the intensity distribution of radiation obtained from each direction. The radiation inspection apparatus 1 includes a radiation source 2, a detector 3, a stage 4, a control unit 5, a stage controller 5 h and a radiation controller 5 g.

  The radiation source 2 emits a radiation beam toward the subject 100. The radiation is, for example, X-rays. A radiation beam is a bundle of radiation that expands in a pyramidal shape with the focal point at the top. The radiation source 2 is, for example, an X-ray tube. In an X-ray tube, a filament and a target such as tungsten are opposed to each other at a target angle of 0 ° or more in a vacuum. The filament is applied with a tube current and a tube voltage according to the imaging conditions to emit an electron beam. The target generates X-rays from the collision of the accelerated electron beam.

  The detector 3 faces the focal point of the radiation source 2. The detector 3 detects a two-dimensional distribution of radiation intensity which is attenuated according to the radiation transmission path. This two-dimensional distribution is called a transmission image. The detector 3 includes, for example, an image intensifier (I.I.) and a camera. I. I. In this case, the scintillator surface made of cesium iodide or the like that emits light when excited by radiation is expanded in a two-dimensional manner, and the two-dimensional distribution of the incident radiation is converted into a fluorescence image while the light intensity of the fluorescence image is multiplied. The camera arranges imaging elements such as CCD and CMOS in parallel and captures a fluorescent image. The detector 3 may be a flat panel detector (FPD). The FPD has a photodiode and a TFT switch along the scintillator surface. The photodiode converts the fluorescent image into charge and stores it, and the TFT switch outputs the charge stored in the photodiode when it receives an ON signal.

  The stage 4 is a mounting table of the subject 100. The stage 4 is interposed between the radiation source 2 and the detector 3, and the mounting surface is directed to the radiation source 2 and spreads orthogonal to the optical axis 2 a of the radiation beam. This stage 4 is position variable with respect to the radiation source 2 and the detector 3. That is, the stage 4 includes the moving mechanism 41. The moving mechanism 41 translates and raises and lowers the stage 4. The translational directions are the X axis direction and the Y axis direction. The X-axis direction is one direction along a plane in which the stage 4 extends. The Y-axis direction is a direction that is orthogonal to the X-axis direction, along the plane in which the stage 4 extends. The elevation direction is the Z-axis direction. The Z-axis direction is orthogonal to the stage 4, in other words, a direction in which the radiation source 2 is in contact with or separated from the radiation source 2.

  The control unit 5 is a so-called computer, and an operation unit 5a such as a CPU that executes an instruction according to the program, a program is expanded, a memory 5b temporarily stores execution results of the instruction and data to be processed, and stores the program and data Storage 5c. Further, the control unit 5 includes a display unit 5 d such as a liquid crystal display or an organic EL display, an operation unit 5 e such as a mouse or a keyboard, and an interface 5 f wired connected to each unit of the radiation inspection apparatus 1.

  FIG. 2 is a flowchart showing an outline operation of the control unit 5. As shown in FIG. 2, when the radiation inspection apparatus 1 is powered on (step S01), the control unit 5 executes a start-up process (step S02). The activation process is activation of the operation system, activation of various applications, and warm-up of each part of the radiation inspection apparatus 1.

  When the start-up process is completed, the control unit 5 enters a quality diagnosis mode (step S03), and performs quality diagnosis of each part represented by the detector 3 (step S04). In this quality diagnosis mode, the radiation beam is irradiated to measure the quality of the detector 3 in a state where there is no mounted object on the stage 4. The control unit 5 stores the past quality measurement results, and calculates and reports the timing at which the life of the detector 3 reaches from the tendency of the quality measurement results.

  After the quality diagnosis mode ends and the subject 100 is placed on the stage 4 (step S05), the control unit 5 sets the imaging conditions of the subject 100 (step S06), and the control unit 5 performs the imaging conditions. The radiation inspection apparatus 1 is controlled in accordance with the above, and the subject 100 is imaged by radiation irradiation (step S07). Typically, the control unit 5 is connected to the stage controller 5h and the radiation controller 5g, and outputs a control signal reflecting imaging conditions to the stage controller 5h and the radiation controller 5g.

  Thereby, a radiation beam is irradiated from the radiation source 2 toward the stage 4 on which the subject 100 is mounted, the radiation transmitted through the subject 100 is detected by the detector 3, and the transmitted image converted into an electrical signal is It is input to the control unit 5. The control unit 5 converts the transmission image into image data such as a bit map represented by gray scale or RGB (step S08), and displays it so that the person in charge of inspection can visually grasp it (step S09).

  That is, as shown in FIG. 3, the control unit 5 cooperates with the stage controller 5h and the radiation controller 5g to set the setting unit 51, the apparatus control unit 52, the image generation unit 53, the image display unit 54, and the quality diagnosis unit 55. Equipped with The control unit 5 may include these units by hardware logic without depending on software.

  The setting unit 51 is provided in the radiation inspection apparatus 1 by the calculation unit 5a, the display unit 5d, and the operation unit 5e. The setting unit 51 is responsible for the photographing condition setting process of step S06. As imaging conditions, radiation related items such as tube voltage related to average energy of X-ray photon and tube current related to X dose, imaging field related items such as imaging magnification and imaging position, and radiation detection such as binning and exposure time Related items can be mentioned. The photographing conditions are set automatically or in accordance with the operation using the operation unit 5e.

  The apparatus control unit 52 is provided in the radiation inspection apparatus 1 by the calculation unit 5a and the interface 5f, and is responsible for the imaging process of the subject 100 in step S07. The apparatus control unit 52 controls the respective units of the radiation inspection apparatus 1 according to the imaging conditions and causes the subject 100 to be imaged by radiation. In detail, the apparatus control unit 52 outputs a control signal including a radiation related item to the radiation controller 5g, outputs a control signal including an imaging field related item to the stage controller 5h, and includes a radiation detection related item. The control signal is output to the detector 3.

  The image generation unit 53 is provided in the radiation inspection apparatus 1 by the interface 5 f of the calculation unit 5 a and the detector 3, and is responsible for the imaging process of step S 08. The image generation unit 53 converts the transmission image input from the detector 3 into image data such as a bitmap having a transmission image representation format such as gray scale or RGB. When the signal input to the detector 3 is analog, the image generation unit 53 quantizes the signal. Logarithmic conversion may be performed.

  The image display unit 54 is provided in the radiation inspection apparatus 1 by the operation unit 5a that manages the video memory and the display unit 5d, and performs the display processing of step S09, and displays the image data generated by the image generation unit 53 on the display unit 5d. . Typically, the image data generated by the image generation unit 53 is laid out on a video memory. The image data is read according to the refresh rate of the RAMDAC and displayed on the display unit 5d.

  The quality diagnosis unit 55 is provided in the radiation inspection apparatus 1 by the calculation unit 5a, the storage 5c, the display unit 5d, and the interface 5f of the radiation source 2. The quality diagnosis unit 55 stores the imaging condition 55a for quality diagnosis, the limit value 55b, and the past data 55c. The limit value 55 b indicates the limit point of the quality of the detector 3. The past data 55c is the quality information of the detector 3, and is obtained by the past quality diagnostic mode.

  The quality diagnosis unit 55 operates in the quality diagnosis mode, and uses the imaging condition 55a for quality diagnosis, the past data 55c, and the latest quality information to make a prediction of deterioration in the quality of the detection unit 3. Then, the quality diagnosis unit 55 calculates the end-of-life timing of the detection unit 3 from the relationship between the quality deterioration prediction and the limit value 55b. The end-of-life timing is a date or date when the period until the end of life is reached starting from the execution of the first quality diagnosis mode is converted.

  Here, the quality information is an average luminance value of all pixels of the two-dimensional distribution received from the detection unit 3. That is, the decrease in quality is the decrease in average luminance value, and the timing at which the average luminance value falls below the limit value is predicted as the end-of-life timing. The operation of the quality diagnostic unit 55 will be described in detail with reference to FIG. FIG. 4 is a flowchart showing the detailed operation of the quality diagnosis unit 55.

  As shown in FIG. 4, in the quality diagnosis mode, the quality diagnosis unit 55 reads out the imaging condition 55a for quality diagnosis from the storage 5c (step S11). Then, the quality diagnosis unit 55 generates a control signal for driving the radiation source 2, the detector 3 and the stage 4 according to the imaging condition 55a, and sends it to the radiation source 2, the detector 3 and the stage 4 (step S12). . Thereby, the radiation source 2 irradiates the radiation beam toward the stage 4 without the object, and the detector 3 facing the radiation source 2 across the stage 4 detects the radiation beam. The detector 3 transmits data of the two-dimensional distribution of the detected radiation beam to the control unit 5.

  The quality diagnosis unit 55 receives the data of the two-dimensional distribution of radiation from the detection unit 3 (step S13), and averages the luminance values of the predetermined region of the two-dimensional distribution, that is, all pixels or a partial range (step S14). And the average result is stored in the storage 5c as luminance value data in association with the current date and time data (step S15). The luminance value data may be obtained by averaging the luminance values of all the pixels received from the detection unit 3 or by averaging the luminance values of a plurality of predetermined pixels, or as the luminance values of the predetermined pixels. good. It is desirable that the predetermined plural pixels and the predetermined pixels be taken, for example, from the vicinity of the center of the detector 3. The date and time data may be generated using a clock IC included in the control unit 5, or may be calculated by the calculation unit 5a based on a clock signal at startup. This date and time data is time information for which quality has been measured, and is typically embedded in the header of luminance value data.

  When the latest luminance value data in the quality diagnosis mode this time is obtained, the quality diagnosis unit 55 reads out the past data (step S16), and calculates the end of life timing using the latest luminance value data and the past data as parameters (step S17). FIG. 5 is a graph showing a method of calculating the end-of-life timing. The horizontal axis is a period, and the vertical axis is a luminance value. The quality diagnosis unit 55 obtains an approximate expression indicating the relationship between the period and the luminance value, and further calculates the period to reach the limit value 55 b from the approximate expression. Then, the calculated period is added to the current date and time to obtain the life end timing represented by the date and time. The approximate expression is derived by linear approximation, exponential approximation, logarithmic approximation, or moving average, and is determined by a method such as the least squares method.

  FIG. 6 is a schematic view showing the screen of the display unit 5d in the quality diagnosis mode. As shown in FIG. 6, when the date and time at which the limit value 55b is reached is calculated, the quality diagnosis unit 55 displays a message presenting the end-of-life arrival timing represented by the calculated date and time on the display unit 5d (step S18). Typically, the quality diagnosis unit 55 generates a message of a character string “YY MM, month, month, and day of DD is the replacement time of the detection unit”, and draws this message at a predetermined address in the video memory. It will change corresponding to the date and time when "YY year MM month DD day" is calculated.

  The quality diagnosis unit 55 may store the calculated date and time, and may display the date and time on the display unit 5d in response to an operation using the operation unit 5e. Further, the quality diagnosis unit 55 may generate an e-mail including a message presenting the date and time, and may transmit the e-mail to a predetermined e-mail address. The e-mail address is stored in advance in the storage 5c.

  As described above, the quality diagnostic unit 55 causes the computing unit 5a to execute the program stored in the storage 5c, whereby the imaging condition storage unit 551, the diagnosis control unit 552, the quality storage unit 553, as shown in FIG. The measurement unit 554, the temporal change analysis unit 555, the life end timing calculation unit 556, and the result notification unit 557 are provided.

  The imaging condition storage unit 551 is provided in the radiation inspection apparatus 1 by the storage 5 c and stores imaging conditions 55 a for quality diagnosis. The diagnosis control unit 552 is provided in the radiation inspection apparatus 1 by the operation unit 5a, reads out the imaging condition 55a of the imaging condition storage unit 551, sends it to the device control unit 52, and irradiates radiation according to the imaging condition 55a for quality diagnosis. The detection unit 3 detects the secondary distribution of the radiation intensity in the absence of the mounting object. The quality storage unit 553 is provided in the radiation inspection apparatus 1 by the calculation unit 5a and the storage 5c, and stores the past data in which the luminance value data obtained in the past quality diagnosis mode is associated with date and time data.

  The measurement unit 554 is provided in the radiation inspection apparatus 1 by the calculation unit 5a, measures the average of the luminance values from the two-dimensional distribution of the radiation intensity detected by the detection unit 3, and generates luminance value data. The temporal change analysis unit 555 is provided in the radiation inspection apparatus 1 by the operation unit 5a, and derives an approximate expression indicating the relationship between the luminance value and the period from the past data 55c and the latest luminance value data. The timing calculation unit 556 is provided in the radiation inspection apparatus 1 by the calculation unit 5a, and calculates the date and time when the brightness value reaches the limit value from the approximate expression and the limit value.

  The result notifying unit 556 is a display control unit that causes the display unit 5 d to display the end of life timing indicated by the date and time, a computing unit 5 a that transmits an e-mail, a network card, or a storage 5 c that stores the end of life timing.

  As described above, the radiation inspection apparatus 1 includes the imaging condition storage unit 551, the diagnosis control unit 552, the quality storage unit 553, the measurement unit 554, the temporal change analysis unit 555, the life end timing calculation unit 556, and the result notification unit 557. Prepare. As a result, the inspector can recognize in advance the timing at which the detector 3 reaches the limit of quality regardless of active and regular quality diagnosis. Therefore, replacement of the detector 3 can be performed systematically, and the quality of the inspection result can be kept good.

  In this embodiment, the start-up time of the radiation inspection apparatus 1 is the quality diagnosis timing. However, the present invention is not limited to this, and various predetermined timings may be used. For example, even if the radiation inspection apparatus 1 is in operation, if the periodic timing arrives in a state where the inspection of the subject 100 is not performed, the quality diagnosis mode may be transitioned to, or the periodic timing may be If the examination of the subject 100 is performed even if it arrives, the quality diagnosis mode may be transitioned to after completion of this examination.

  In addition, an example in which the surface of the stage 4 is installed so as to spread orthogonal to the optical axis 2a of the radiation beam has been described. As shown in FIG. 8, the positional relationship between the radiation source 2, the detector 3 and the stage 4 is not limited thereto, and the subject 100 placed on the stage 4 is interposed between the radiation source 2 and the detector 3. You should do it. For example, the stage 4 may be arranged such that the surface extends in parallel with the optical axis 2 a of the radiation beam, and the radiation beam may be irradiated to the side of the subject 100 mounted on the stage 4.

Second Embodiment
Next, a radiation inspection apparatus 1 according to a second embodiment will be described in detail with reference to the drawings. The same components and functions as those of the first embodiment are designated by the same reference numerals and their detailed description will be omitted.

  FIG. 9 shows I.I. I. Is a schematic view showing the quality deterioration of the detector 3 formed by As shown in FIG. I. In this case, since the luminance value obtained from the peripheral edge of the detector 3 is relatively lower than that in the central region, when the luminance value of the transmission image 31 decreases as a whole, The low luminance value pixel 31a is generated, and the low luminance value pixel 31a spreads from the periphery to the center. Moreover, FIG. 10 is a schematic diagram which shows the quality degradation of the detector 3 which consists of FPD. As shown in FIG. 10, when the detector 3 is an FPD, dot omissions occur randomly, and the low luminance value pixels 31 a tend to increase randomly in the transmission image 31.

  Therefore, the quality diagnosis unit 55 counts the number of pixels below the predetermined luminance value among all pixel values of the two-dimensional distribution received from the detection unit 3. Then, the quality diagnosis unit 55 increases the number of pixels below the predetermined luminance value according to the quality deterioration, and predicts the date and time when it exceeds the limit value 55b. At this time, the quality information is a count value of the number of pixels below the predetermined luminance value.

  That is, the measuring unit 554 counts the number of pixels equal to or less than a predetermined luminance value by binarized image processing and image scanning. The quality storage unit 553 stores the past data 55c in which the count value and the date and time data are associated. The temporal change analysis unit 555 derives an approximate expression indicating the relationship between the count value and the period. The end-of-life timing calculation unit 556 calculates the end-of-life time that is the date and time when the count value reaches the limit value 55 b from this approximate expression and the limit value 55 b.

  FIG. 11 is a flowchart showing the detailed operation of the quality diagnosis unit 55. As shown in FIG. 11, in the quality diagnosis mode, the quality diagnosis unit 55 reads out the imaging condition 55a for quality diagnosis from the storage 5c (step S21). Then, the quality diagnosis unit 55 generates a control signal for driving the radiation source 2, the detector 3 and the stage 4 according to the imaging condition 55a, and sends it to the radiation source 2, the detector 3 and the stage 4 (step S22) .

  Then, the quality diagnosis unit 55 receives data of the two-dimensional distribution of radiation from the detection unit 3 (step S23), binarizes the data of the two-dimensional distribution (step S24), and counts the number of pixels less than a predetermined luminance value. (Step S25). The quality diagnosis unit 55 stores the count value in the storage 5c in association with the current date and time data (step S26). The count value data specified at this date and time is treated as past data 55c in the next quality diagnosis mode.

  When the latest count value data in the quality diagnosis mode this time is obtained, the quality diagnosis unit 55 reads the past data 55c (step S27), and calculates the end of life timing using the latest count value data and the past data 55c as parameters. (Step S28). FIG. 12 is a schematic view showing a method of calculating the end-of-life timing. The quality diagnosis unit 55 obtains an approximate expression indicating the relationship between time and the count value by the least square method or the like, and further calculates a period in which the count value reaches the limit value 55 b from the approximate expression. Then, the calculated period is added to the current date and time to obtain the life end timing represented by the date and time. When the date and time at which the limit value 55 b is reached is calculated, the quality diagnosis unit 55 displays a message presenting the calculated date and time on the display unit 5 d (step S 29).

  As described above, the measuring unit 554 measures the count value by counting the number of pixels exceeding the predetermined luminance value as the quality information. The time-dependent change analysis unit 555 derives an approximate expression indicating the relationship between the count value and the period. Then, the end-of-life timing calculation unit 556 calculates the end-of-life timing based on the approximate expression and the limit value 55b. This also allows the inspector in advance to recognize in advance the timing at which the detector 3 reaches the limit of quality, regardless of active and regular quality diagnosis. Therefore, replacement of the detector 3 can be performed systematically, and the quality of the inspection result can be kept good. The range to be counted is not limited to all the pixels of the transmission image 31, but may be pixels in a partial range.

(Modification 1)
Next, a modification of the radiation inspection apparatus 1 according to the second embodiment will be described in detail with reference to the drawings. The same components and functions as those of the second embodiment are designated by the same reference numerals and their detailed description will be omitted.

  After binarizing the two-dimensional distribution received from the detection unit 3, the quality diagnosis unit 55 counts the number of pixels exceeding the predetermined luminance value, and the number of pixels exceeding the predetermined luminance value decreases according to the quality deterioration. It is also possible to predict the date and time below the limit value 55b. That is, in the quality diagnostic unit 55, the measuring unit 554 counts the number of pixels below a predetermined luminance value by binarized image processing and image scanning, and calculates the timing when the number of pixels above the predetermined luminance value reaches a lower limit. .

  FIG. 13 is a flowchart showing the detailed operation of the quality diagnosis unit 55. As shown in FIG. 13, in the quality diagnosis mode, the quality diagnosis unit 55 reads out the imaging condition 55a (step S31), and sends out a control signal according to the imaging condition 55a (step S32). When receiving the two-dimensional distribution of the radiation detected by the detector 3 (step S33), the quality diagnosis unit 55 binarizes the data of the two-dimensional distribution (step S34) and counts the number of pixels having a predetermined luminance value or more (step S34). Step S35). The quality diagnosis unit 55 stores the count value in the storage 5c in association with the current date and time data (step S36).

  When the latest count value data is obtained, the quality diagnosis unit 55 reads the past data 55c (step S37), and calculates the life end timing (step S38). FIG. 14 is a graph showing a method of calculating the end-of-life timing. The horizontal axis is date and time, and the vertical axis is a count value. The quality diagnosis unit 55 obtains an approximate expression indicating the relationship between time and the count value by the least square method or the like, and further calculates a period in which the count value reaches the limit value 55 b from the approximate expression. Then, the calculated period is added to the current date and time to obtain the life end timing represented by the date and time. When the date and time to reach the limit value 55b is calculated, the quality diagnosis unit 55 displays a message presenting the calculated date and time on the display unit 5d (step S39).

  Thus, the measuring unit 554 measures the count value by counting the number of pixels below the predetermined luminance value as the quality information. The time-dependent change analysis unit 555 derives an approximate expression indicating the relationship between the count value and the period. Then, the end-of-life timing calculation unit 556 calculates the end-of-life timing based on the approximate expression and the limit value. This also allows the inspector in advance to recognize in advance the timing at which the detector 3 reaches the limit of quality, regardless of active and regular quality diagnosis. Therefore, replacement of the detector 3 can be performed systematically, and the quality of the inspection result can be kept good. The range to be counted is not limited to all the pixels of the transmission image 31, but may be pixels in a partial range.

(Modification 2)
Next, a second modification of the radiation inspection apparatus 1 according to the second embodiment will be described in detail with reference to the drawings. The same components and functions as those of the second embodiment or the first embodiment are designated by the same reference numerals and their detailed description will be omitted.

  As shown in FIG. 15, a central region 31 b exists in the transmission image 31. The central area 31 b is an important area of particular interest to the inspector, and the required quality is high. Therefore, the quality diagnosis unit 55 counts the number of pixels below the predetermined luminance value among the pixel groups belonging to the central region 31b of the transmission image 31, and the number of pixels below the predetermined luminance value increases according to the quality deterioration. And predict the date and time above the limit 55b.

  FIG. 16 is a flowchart showing the detailed operation of the quality diagnosis unit 55. As shown in FIG. 16, in the quality diagnosis mode, the quality diagnosis unit 55 reads the imaging condition 55a (step S41), and sends out a control signal according to the imaging condition 55a (step S42). When receiving the two-dimensional distribution of the radiation detected by the detector 3 (step S43), the quality diagnosis unit 55 extracts the central region 31b (step S44). Typically, pixel values within a predetermined range of particular interest may be extracted from the center coordinates of the two-dimensional distribution.

  When the central area 31b is extracted, the quality diagnosis unit 55 binarizes the data of the central area 31b (step S45), and counts the number of pixels having a predetermined luminance value or less (step S46). The quality diagnosis unit 55 stores the count value in the storage 5c in association with the current date and time data (step S47). When the latest count value data is obtained, the quality diagnosis unit 55 reads the past data 55c (step S48), and calculates the life end timing (step S49). Then, the quality diagnosis unit 55 displays a message presenting the calculated date and time on the display unit 5d (step S50).

  The measuring unit 554 counts the inside of the central region 31 b in the transmission image 31. As a result, since the quality can be measured for the important areas of particular interest to the inspector, the reliability of the end of life can be improved. Therefore, it is desirable that the limit value 55 b related to the central region 31 b be stricter than the value for all the pixels of the transmission image 31. The count value data may be acquired by counting the number of pixels exceeding the predetermined luminance value.

Third Embodiment
Next, a radiation inspection apparatus 1 according to a third embodiment will be described in detail with reference to the drawings. The same components and functions as those of the first or second embodiment are designated by the same reference numerals and their detailed description will be omitted.

  As shown in FIG. 17, the radiation inspection apparatus 1 has a step body 6 separately from the apparatus. The step body 6 is placed on the stage 4 in the quality diagnosis mode, and removed from the stage 4 when the quality diagnosis mode is finished. The bottom of the step body 6 is flat, the top surface facing the bottom surface has a step shape, and the steps from the bottom of the step 6 have different thicknesses. When the step body 6 is photographed by the radiation inspection apparatus 1, as shown in FIG. 18, the luminance varies depending on the thickness of each step.

  The control unit 5 of the radiation inspection apparatus 1 calculates the end-of-life timing at which the two adjacent luminance differences 61 become equal to or less than the limit value 55b, and notifies the person in charge of the inspection. The measurement unit 554 measures the luminance difference 61 as the quality information, and the quality storage unit 553 associates the luminance difference 61 with the date and time data and stores it.

  FIG. 19 is a flowchart showing the operation of the quality diagnosis unit 55. As shown in FIG. 19, in the quality diagnosis mode, the person in charge of inspection first mounts the step body 6 on the stage 4 (step S61). The quality diagnosis unit 55 reads the imaging condition 55a for quality diagnosis from the storage 5c (step S62), generates a control signal according to the imaging condition 55a, and sends it to the radiation source 2, the detector 3 and the stage 4 (step S63).

  Thereby, the radiation beam is irradiated toward the step body 61, and the data of the two-dimensional distribution of the radiation transmitted through the step body 61 is detected by the detector 3. The quality diagnosis unit 55 receives data of the two-dimensional distribution of radiation transmitted through the step body 6 (step S64), and calculates the luminance difference 61 (step S65).

  In step S <b> 65, first, an area other than the pixel indicating the stage 4 is extracted to specify the image area of the step body 6. When the image area of the step body 6 is specified, a line along the raising and lowering direction of the step body 6 is scanned to extract the luminance value at each position in the line direction. Thereby, the luminance value graph in which the luminance values for each row shown in FIG. 18 are specified is obtained. The quality diagnosis unit 55 stores two luminance value acquisition positions in advance. The two luminance value acquisition positions are divided into adjacent steps. The luminance difference calculation unit 559 reads the luminance values at the two luminance value acquisition positions from the luminance value graph, and subtracts the read luminance values. Thereby, the luminance difference 61 is obtained.

  When the luminance difference 61 is calculated, the quality diagnosis unit 55 stores the luminance difference 61 in the storage 5c in association with the current date and time data (step S66). The data of the luminance difference 61 specified at this date and time is treated as past data 55c in the next quality diagnosis mode.

  When the latest data of the luminance difference 61 according to the quality diagnosis mode of this time is obtained, the quality diagnosis unit 55 reads the past data 55c (step S67), and the life reaches using the latest luminance difference 61 data and the past data 55c as parameters. The timing is calculated (step S68). That is, the quality diagnosis unit 55 obtains an approximate expression indicating the relationship between the period and the luminance difference 61, and further calculates the period in which the luminance difference 61 reaches the limit value 55b from the approximate expression. Then, the calculated period is added to the current date and time to obtain the life end timing represented by the date and time. When the date and time of reaching the limit value 55b is calculated, the quality diagnosis unit 55 displays a message presenting the calculated end-of-life timing on the display unit 5d (step S69).

  Thus, in the radiation inspection apparatus 1, the step body 6 is mounted on the stage 4 in the quality diagnosis mode. The step body 6 has a step shape having a plurality of thicknesses. The measuring unit 554 measures, as quality information, the difference between two adjacent luminance values 61, and the temporal change analysis unit 55 is an approximate expression showing the relationship between the luminance difference 61 and the period based on the past luminance difference 61. Derive This also allows the inspector in advance to recognize in advance the timing at which the detector 3 reaches the limit of quality, regardless of active and regular quality diagnosis. Therefore, replacement of the detector 3 can be performed systematically, and the quality of the inspection result can be kept good.

  In addition, in the case of obtaining the end-of-life timing based on the luminance difference 61 of a specific step, at least two steps of the step body 61 are sufficient. On the other hand, the step body 61 has, for example, at least two steps such as 10 steps, and the quality diagnosis unit 55 obtains the brightness difference 61 of each adjacent step, and obtains the life reaching timing for each step based on each brightness difference 61. You may Then, the end of life reaching the earliest may be searched for and displayed on the display unit 5d.

(Modification)
A modification of the radiation inspection apparatus 1 according to the third embodiment will be described in detail with reference to the drawings. The same components and functions as those of the first to third embodiments are denoted by the same reference numerals and detailed description thereof will be omitted.

  As an effect equivalent to placing the step body 6 on the stage 4, the quality diagnosis unit 55 causes the radiation source 2 to irradiate a radiation beam with two types of doses, and the luminance difference 61 obtained by the two types of radiation irradiation Is used to calculate the end of life. The step body 6 is not placed on the stage 4, and a radiation beam is irradiated in a state where there is no placed object. The two doses are relatively strong and weak. The quality diagnostic unit 55 stores in advance two types of imaging conditions 55a of high dose and imaging conditions 55a of low dose.

  FIG. 20 is a flowchart showing the detailed operation of the quality diagnosis unit 55. As shown in FIG. 20, the quality diagnostic unit 55 reads out two types of imaging conditions 55a for quality diagnosis from the storage 5c (step S71), generates control signals according to the high-dose imaging conditions 55a, and detects radiation source 2 To the stage 3 and the stage 4 (step S72). Thereby, the radiation beam of high dose is irradiated in the state without a mounting object, and the data of the two-dimensional distribution of the radiation of high dose are detected by the detector 3. The quality diagnosis unit 55 receives data of the two-dimensional distribution of high dose radiation (step S73).

  Furthermore, the quality diagnosis unit 55 generates a control signal according to the low-dose imaging condition 55a, and sends it to the radiation source 2, the detector 3 and the stage 4 (step S74). As a result, the radiation beam of low dose is irradiated in the absence of the object, and the data of the two-dimensional distribution of the radiation of low dose is detected by the detector 3. The quality diagnosis unit 55 receives data of the two-dimensional distribution of low dose radiation (step S75).

  The quality diagnosis unit 55 calculates the luminance difference 61 from the data of the two-dimensional distribution of the high dose radiation and the data of the two-dimensional distribution of the low dose radiation (step S76). Each luminance value may be the average value of each pixel or may be the luminance value of the same predetermined pixel. When the luminance difference 61 is calculated, the quality diagnosis unit 55 stores the luminance difference 61 in the storage 5c in association with the current date and time data (step S77). The data of the luminance difference 61 specified at this date and time is treated as past data 55c in the next quality diagnosis mode.

  When the latest data of the luminance difference 61 according to the quality diagnosis mode of this time is obtained, the quality diagnosis unit 55 reads the past data 55c (step S78), and the end of life is reached using the data of the latest luminance difference 61 and the past data as parameters. Are calculated (step S79). Then, the quality diagnosis unit 55 displays a message presenting the calculated end-of-life timing on the display unit 5d (step S80).

  As described above, in the case of imaging with both high dose and low dose, an effect equivalent to the placement of the two-step body 61 can be obtained, and the time and effort for installing the step body 61 can be omitted.

(Other embodiments)
Although the embodiments of the present invention have been described herein, this embodiment is presented as an example and is not intended to limit the scope of the invention. The embodiment as described above can be implemented in other various forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. The embodiments and the modifications thereof are included in the invention described in the claims and the equivalents thereof as well as included in the scope and the gist of the invention.

  For example, although the first to third embodiments and the respective modifications have been described, two or more of these are used in combination, and among the obtained life end arrival timings, the earliest life arrival timing is selected. May be notified to the person in charge of inspection.

  Further, a plurality of types of imaging conditions 55a for quality diagnosis may be stored in the imaging condition storage unit 551 of the quality diagnosis unit 55, and quality diagnosis may be performed using each imaging condition 55a. The imaging conditions 55a for multiple types of quality diagnosis include, for example, a basic imaging condition 55a having a predetermined tube current and a tube voltage, an imaging condition 55a for a high dose of tube current and tube voltage higher than the basic imaging condition 55a, It is the imaging | photography conditions 55a of low dose of tube current and tube voltage lower than the fundamental imaging | photography conditions 55a.

  FIG. 21 is a flowchart showing the quality diagnosis mode in the case of storing a plurality of types of imaging conditions 55a. As shown in FIG. 21, the quality diagnostic unit 55 reads out a plurality of types of imaging conditions 55a for quality diagnosis from the storage 5c (step S81), and obtains quality information according to each imaging condition 55a (step S82).

  In this step 82, the quality diagnosis unit 55 sends a control signal according to, for example, the basic imaging conditions 55a to each part of the radiation inspection apparatus 1 to obtain data of a two-dimensional distribution of radiation of the basic dose. The measuring unit 554 measures the quality information such as the luminance value, the count value or the luminance difference from the data of the two-dimensional distribution, associates the information with the information identifying the basic imaging condition 55a, and stores the information in the quality storage unit 553. Furthermore, the quality diagnosis unit 55 obtains two-dimensional distribution data according to the high-dose imaging condition 55a, and the measurement unit 554 measures quality information from the two-dimensional distribution data to identify the high-dose imaging condition 55a. To the information to be stored in the quality storage unit 553. Then, the quality diagnosis unit 55 obtains two-dimensional distribution data according to the low-dose imaging condition 55a, and the measurement unit 554 measures quality information from the two-dimensional distribution data and identifies the low-dose imaging condition 55a. To the information to be stored in the quality storage unit 553.

  Next, the quality diagnosis unit 55 reads the past data 55c linked to each shooting condition 55a (step S83), and calculates each life reaching timing using the latest quality information data and the past data as parameters (step S84). ).

  In step S84, the quality diagnostic unit 55 determines, for example, the basic imaging conditions 55a from the quality data obtained in the current quality diagnosis mode according to the past data 55c linked to the basic imaging conditions 55a and the basic imaging conditions 55a. Calculate the end of life based on. In addition, the quality diagnosis unit 55, for example, the high-dose imaging condition 55a from the quality data obtained in the current quality diagnosis mode according to the past data 55c linked to the high-dose imaging condition 55a and the high-dose imaging condition 55a. Calculate the end of life based on. Furthermore, the quality diagnosis unit 55 determines, for example, the low-dose imaging condition 55a from the quality data obtained in the current quality diagnosis mode according to the past data 55c linked to the low-dose imaging condition 55a and the low-dose imaging condition 55a. Calculate the end of life based on.

  Then, the quality diagnosis unit 55 displays a message presenting the calculated end-of-life timing on the display unit 5d (step S85). For example, as shown in FIG. 22, the display unit 5d displays the end of life reaching timing obtained based on the basic imaging conditions 55a together with the contents of the basic imaging conditions 55a such as the tube current and the tube voltage. The end-of-life timing obtained based on the imaging condition 55a is displayed together with the contents of the high-dose imaging condition 55a such as the tube current and the tube voltage, and the end-of-life timing obtained based on the low-dose imaging condition 55a is It is displayed together with the contents of the basic imaging conditions 55a such as current and tube voltage.

  As described above, according to the type of the imaging condition 55 a, the radiation inspection apparatus 1 can obtain each life end timing. Therefore, the user can refer to the end-of-life arrival timing obtained under the imaging condition 55a for quality diagnosis closest to the imaging condition frequently used when inspecting the subject 100. Therefore, the radiation inspection apparatus 1 can notify the user of the more reliable end-of-life arrival timing. When one or more types of imaging conditions frequently used by the user are input using the operation unit 5e, the input imaging conditions may be stored in the imaging condition storage unit 551 of the quality diagnosis unit 55 for quality diagnosis.

  Further, as shown in FIG. 23, the quality diagnosis unit 55 may be provided with a standard life storage unit 558 which previously stores standard life arrival timing. The standard life storage unit 558 is provided in the radiation inspection apparatus 1 mainly by the storage 5 c. In this case, the result notifying unit 557 reports both the end of life end timing and the standard end of life end timing based on the usage state obtained from the past data 55c and the latest quality information. The standard life end timing is a timing at which a predetermined failure rate is obtained by, for example, Weibull analysis, starting from the start of use of the radiation inspection apparatus 1. The end-of-life timing calculation unit 556 may store the start time of use, convert the standard end-of-life end timing into date and time, and the result notification unit 557 may display the end-of-life end timing converted into date and time.

  If both standard end-of-life timing and end-of-life timing based on usage conditions are reported, the user can refer to both the end-of-life timing based on statistics and the end-of-life timing based on use environment. More information will be available to determine when to exchange.

  In addition, the end-of-life timing calculation unit 556 may calculate the final end-of-life timing by referring to the standard end-of-life timing and the end-of-life timing based on the use situation. FIG. 24 is a flowchart showing the operation of the end-of-life timing calculation unit 556 when there is a standard end-of-life end timing. As shown in FIG. 24, when the end-of-life timing calculation unit 556 calculates the end-of-life end timing based on the usage status from the past data and the current quality information (step S91), it reads the standard end-of-life end timing (step S92).

  Next, the end-of-life timing calculation unit 556 stores a weighting value in advance, and calculates a final end-of-life arrival timing from the weighting value and both end-of-life arrival timings (step S93). Then, the result notifying unit 557 gives notification as this final life end timing (step S94).

  In this step S93, the end-of-life timing calculation unit 556 may calculate the time difference between both end-of-life arrival timings, and set the time when the time difference is divided by the weighting value as the final end-of-life arrival timing. In this case, the weighting value is a ratio, and if it is 0.5, it is an intermediate time point. Also, for example, when the weighting value is 0.75, the time difference is 1, and the point at which 75% of the standard life end timing side or the life end timing side based on the use situation progresses 75% is used as the final life end timing.

  If the final end of life is calculated from this standard end of life timing and the end of life end timing based on the usage situation, statistical standard end of life end timing and the end of life end timing based on the user's usage environment are calculated. Both are taken into consideration, and high reliability is given by the end-of-life timing notified to the user.

DESCRIPTION OF SYMBOLS 1 radiation inspection apparatus 2 radiation source 2a optical source 3 detector 31 transmission image 31a low luminance value pixel 31b central region 4 stage 41 moving mechanism 5 control unit 5a operation unit 5b memory 5c storage 5d display unit 5e operation unit 5f interface 5g radiation controller 5h Stage controller 51 Setting unit 52 Device control unit 53 Image generation unit 54 Image display unit 55 Quality diagnosis unit 55a Shooting condition 55b Limit value 55c Past data 551 Shooting condition storage unit 552 Diagnostic control unit 553 Quality storage unit 554 Measuring unit 555 Change over time Analysis unit 556 Life end reaching timing calculation unit 557 Result notifying unit 558 Standard life storage unit 6 Stepped body 61 Brightness difference 100 Subject

Claims (12)

A radiation source for emitting radiation;
A detector for detecting radiation;
A stage interposed between the radiation source and the detector and on which an object can be placed;
A control unit which shifts to a quality diagnosis mode at a predetermined timing and controls the radiation source, the detector, and the stage according to predetermined imaging conditions;
Equipped with
The control unit
A measuring unit that measures the quality of the detector based on the transmission image photographed according to the photographing condition;
A first storage unit that stores the measurement result of the measurement unit as quality information in association with time information;
A second storage unit that stores the limit value of the quality information;
An operation unit that analyzes temporal change of the quality information, and calculates a life reaching timing at which the quality information reaches the limit value based on the temporal change;
A notification unit that notifies the end of the life end;
To have
Radiation inspection apparatus characterized by The measurement unit measures a luminance value of the transmission image as the quality information,
The arithmetic unit is
A temporal change analysis unit that derives an approximate expression indicating a relationship between a luminance value and a period based on the luminance value accumulated by the first storage unit;
A timing calculation unit that calculates the end-of-life timing based on the approximate expression and the limit value;
To have
The radiation inspection apparatus according to claim 1, characterized in that The measuring unit measures an average of luminance values of a predetermined area in the transmission image.
The radiation inspection apparatus according to claim 2, characterized in that The predetermined area is all pixels in the transmission image or pixels in a partial range,
The radiation inspection apparatus according to claim 3, characterized in that The measurement unit measures a count value by counting the number of pixels exceeding a predetermined luminance value as the quality information.
The arithmetic unit is
A temporal change analysis unit that derives an approximate expression indicating a relationship between a count value and a period based on the count value accumulated by the first storage unit;
A timing calculation unit that calculates the end-of-life timing based on the approximate expression and the limit value;
To have
The radiation inspection apparatus according to claim 1, characterized in that The measuring unit counts all pixels in the transmission image, a predetermined area, or a central area.
The radiation inspection apparatus according to claim 5, characterized in that The measurement unit measures a count value by counting the number of pixels below a predetermined luminance value as the quality information.
The arithmetic unit is
A temporal change analysis unit that derives an approximate expression indicating a relationship between a count value and a period based on the count value accumulated by the first storage unit;
A timing calculation unit that calculates the end-of-life timing based on the approximate expression and the limit value;
To have
The radiation inspection apparatus according to claim 1, characterized in that The measuring unit counts all pixels in the transmission image, a predetermined area, or a central area.
The radiation inspection apparatus according to claim 7, characterized in that It has a step-like stepped body mounted on the stage in the quality diagnosis mode and having a plurality of thicknesses,
The measurement unit measures, as the quality information, a difference between two adjacent luminance values.
The arithmetic unit is
A temporal change analysis unit which derives an approximate expression indicating a relationship between the difference in luminance value and a period based on the difference in luminance value accumulated in the first storage unit;
A timing calculation unit that calculates the end-of-life timing based on the approximate expression and the limit value;
To have
The radiation inspection apparatus according to claim 1, characterized in that The control unit controls the radiation source, the detector, and the stage according to a plurality of types of imaging conditions to cause imaging.
The measurement unit measures the quality of the detector based on each transmission image captured according to each of the plurality of types of imaging conditions,
The first storage unit accumulates the measurement results of the measurement unit for each imaging condition,
The calculation unit calculates the life end timing for each of the plurality of types of imaging conditions,
The notification unit notifies the end of life at each of the plurality of types of imaging conditions.
The radiation inspection apparatus according to claim 1, characterized in that And a third storage unit for storing in advance the standard end-of-life timing,
The notification unit notifies both of the life end timing calculated by the calculation unit and the specified life end timing stored in the third storage unit.
The radiation inspection apparatus according to any one of claims 1 to 10, characterized in that And a third storage unit for storing in advance the standard end-of-life timing,
The calculation unit calculates further life arrival timing based on the life arrival timing calculated by the calculation unit and the standard life arrival timing stored in the third storage unit.
The notification unit notifies of the further life end timing,
The radiation inspection apparatus according to claim 11, characterized in that

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