JP2019015577A - X-ray inspection device - Google Patents

Abstract

To provide an X-ray inspection device that can detect degradation of a sensor properly.SOLUTION: An X-ray inspection device 10 includes: an X-ray source 20; a first sensor 31; a second sensor 32; and a detection unit 62. The X-ray source irradiates an inspection target object A with an X-ray. The first sensor detects the X-ray in a first energy band emitted from the X-ray source and outputs a first output value about the detected X-ray. The second sensor detects the X-ray in a second energy band emitted from the X-ray source and outputs a second output value about the detected X-ray. The detection unit detects degradation of at least one of the first sensor and the second sensor on the basis of at least one of the first output value and the second output value.SELECTED DRAWING: Figure 11

Description

  The present invention relates to an X-ray inspection apparatus that inspects an inspection object by irradiating the inspection object such as food with X-rays.

  Conventionally, as disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 10-318943), based on two transmitted X-ray data obtained by irradiating an object with two types of X-rays having different energy bands. An X-ray inspection apparatus for inspecting an inspection object is known. As such an X-ray inspection apparatus, for example, an apparatus that obtains a difference in luminance between two X-ray transmission images having different energy characteristics and detects a foreign substance contained in the inspection object is widely used.

  However, if the sensor for detecting X-rays deteriorates due to long-term use of the X-ray inspection apparatus, the output value of the sensor relating to the detected X-rays gradually decreases. When the X-ray inspection apparatus includes two sensors that detect two types of X-rays having different energy bands, the two sensors may deteriorate at different speeds. In that case, since the output values of the two sensors decrease at different speeds, the difference in luminance between the two X-ray transmission images gradually changes, and as a result, the accuracy of inspection of the inspection object may decrease. . In order to maintain the accuracy of the inspection of the inspected object, it is necessary to perform a process of adjusting the output values of the two sensors when it is found that the two sensors have deteriorated to some extent. For this reason, when the X-ray inspection apparatus includes two sensors, a function capable of appropriately detecting deterioration of each sensor is required.

  An object of the present invention is to provide an X-ray inspection apparatus that can appropriately detect deterioration of a sensor.

  The X-ray inspection apparatus according to the present invention includes an X-ray source, a first sensor, a second sensor, and a detection unit. The X-ray source irradiates the inspection object with X-rays. The first sensor detects X-rays in the first energy band irradiated from the X-ray source, and outputs a first output value related to the detected X-rays. The second sensor detects X-rays in the second energy band irradiated from the X-ray source, and outputs a second output value related to the detected X-rays. The detection unit detects deterioration of at least one of the first sensor and the second sensor based on at least one of the first output value and the second output value.

  This X-ray inspection apparatus inspects an inspection object using two sensors. The two sensors respectively detect two types of X-rays that are irradiated from the X-ray source and pass through the object to be inspected and that have different energy bands. This X-ray inspection apparatus has a function of detecting sensor deterioration based on the output value of the sensor. The output value of the sensor is, for example, a value related to the intensity of X-rays that have passed through the inspection object. Since this X-ray inspection apparatus detects the deterioration of the sensor based on the output value of the sensor, the deterioration of the sensor can be detected at an appropriate timing.

  The X-ray inspection apparatus preferably further includes a storage unit that stores the first output value output by the first sensor and the second output value output by the second sensor. In this case, the detection unit detects that at least one of the first output value and the second output value has decreased by a predetermined value or more based on the first output value and the second output value stored in the storage unit. In this case, it is preferable to detect deterioration of the sensor.

  In this case, the X-ray inspection apparatus detects a decrease in the sensor output value by detecting a decrease in the output value of the sensor. For example, when the output value of the sensor at the start of use of the X-ray inspection apparatus is stored and it is detected that the output value of the sensor has decreased by a predetermined value or more than at the start of use of the X-ray inspection apparatus, Deterioration is detected.

  Further, when the first sensor is disposed at a position closer to the X-ray source than the second sensor, the detection unit has a first output value that is a predetermined value based on the first output value stored in the storage unit. It is preferable to detect the deterioration of the sensor when it is detected that the reduction has occurred.

  In this case, the X-ray inspection apparatus detects the deterioration of the sensor by detecting a decrease in the output value of the sensor closer to the X-ray source of the two sensors. That is, the deterioration of the sensor that is more likely to deteriorate due to the influence of X-rays is detected.

  Moreover, it is preferable that a detection part detects degradation of a sensor, when it detects that the difference of a 1st output value and a 2nd output value is more than predetermined value.

  In this case, when the X-ray inspection apparatus detects that the difference between the output values of the two sensors has become a predetermined value or more, it detects the deterioration of the sensor. Therefore, even when the deterioration rates of the two sensors are different, the deterioration of the sensor is appropriately detected.

  The X-ray inspection apparatus further includes a conversion unit that executes a conversion process for converting at least one of the first output value and the second output value so that the first output value matches or approximates the second output value. It is preferable. In this case, it is preferable that the detection unit detects the deterioration of the sensor when detecting that the difference between the first output value and the second output value converted by the conversion unit is equal to or greater than a predetermined value.

  In this case, for example, the X-ray inspection apparatus performs a conversion process for matching the output values of the two sensors based on a conversion function for matching one of the two X-ray transmission images obtained from the output values of the two sensors to the other. Do. Therefore, even when the deterioration rates of the two sensors are different, the deterioration of the sensor is appropriately detected.

  Moreover, it is preferable that a conversion part updates the data used for a conversion process automatically, or proposes the update of the said data.

  In this case, for example, the X-ray inspection apparatus periodically updates the conversion function used for the conversion process for combining the output values of the two sensors, or updates the conversion function by the operator of the X-ray inspection apparatus. Propose to.

  The X-ray inspection apparatus preferably further includes an inspection unit that inspects the object to be inspected using the first output value and the second output value. In this case, it is preferable that the conversion unit automatically executes data used for the conversion process based on the first output value and the second output value obtained when the inspection unit inspects the inspection object.

  In this case, the X-ray inspection apparatus automatically updates the conversion function used for the conversion process for combining the output values of the two sensors based on the output value of the sensor obtained by the inspection of the inspection object. For this reason, the sensor deterioration is appropriately detected only by using the X-ray inspection apparatus for the inspection of the inspection object.

  Moreover, it is preferable that the X-ray inspection apparatus further includes a notification unit that notifies information related to sensor degradation when the detection unit detects sensor degradation.

  For example, the X-ray inspection apparatus can warn the operator of the X-ray inspection apparatus that the sensor has deteriorated, and can prompt the user to replace the sensor at an appropriate time.

  The X-ray inspection apparatus according to the present invention can appropriately detect sensor deterioration.

It is a perspective view which shows the external appearance of the X-ray inspection apparatus 10 which is one Embodiment of this invention. 1 is a schematic view of an inspection line 100 in which an X-ray inspection apparatus 10 is incorporated. 1 is a schematic diagram of the inside of a shield box 11 of an X-ray inspection apparatus 10. FIG. 3 is a schematic diagram showing details of a sensor unit 30. FIG. 4 is a graph showing an example of the intensity of transmitted X-rays detected by the line sensors 31 and 32. 3 is a block diagram of a control device 50. FIG. FIG. 7A is an example of the low-energy transmission image P1 of the inspection object A. FIG. 7B is an example of a high-energy transmission image P2 of the inspection object A. FIG. 7C shows a low-energy converted low-energy transmission image P1a acquired by the luminance conversion processing of the low-energy transparent image P1 in FIG. It is an example of the low energy histogram H1 and the high energy histogram H2. It is an example of the low energy histogram integration curve C1 and the high energy histogram integration curve C2. 5 is a flowchart of image processing by an image processing unit 61. It is a graph showing an example of the time change of the output value of the line sensors 31 and 32. FIG.

  Embodiments of the present invention will be described with reference to the drawings. The embodiment described below is one specific example of the present invention, and does not limit the technical scope of the present invention.

(1) Overall Configuration of X-ray Inspection Apparatus FIG. 1 is a perspective view showing the appearance of an X-ray inspection apparatus 10 that is an embodiment of the present invention. FIG. 2 is a schematic diagram of an inspection line 100 in which the X-ray inspection apparatus 10 is incorporated. The inspection line 100 inspects the inspection object A. The inspected object A is, for example, a packaged food. In the inspection line 100, the inspection object A is conveyed to the X-ray inspection apparatus 10 by the pre-stage conveyor 60. In FIG. 2, the conveyance direction of the inspection object A is indicated by an arrow.

  The X-ray inspection apparatus 10 determines pass / fail of the inspection object A by irradiating the inspection object A continuously conveyed by the front conveyor 60 with X-rays. Specifically, the X-ray inspection apparatus 10 performs a foreign matter mixing inspection of the inspection object A, and classifies the inspection object A as a non-defective product or a defective product based on the inspection result. The inspection result obtained by the X-ray inspection apparatus 10 is sent to a distribution mechanism 70 disposed on the downstream side of the X-ray inspection apparatus 10. The sorting mechanism 70 sends the inspected object A, which is determined to be a non-defective product by the X-ray inspection apparatus 10, to the rear conveyor 80 that discharges the non-defective product. The distribution mechanism 70 distributes the inspection object A determined to be defective by the X-ray inspection apparatus 10 in the defective product discharge directions 90 and 91 and discharges it from the inspection line 100.

(2) Detailed description of the X-ray inspection apparatus The X-ray inspection apparatus 10 mainly includes a shield box 11, a transport unit 12, an X-ray irradiator (X-ray source) 20, a sensor unit 30, a monitor 40, And a control device 50.

(2-1) Shield Box FIG. 3 is a schematic diagram of the inside of the shield box 11 of the X-ray inspection apparatus 10. The shield box 11 is a casing of the X-ray inspection apparatus 10. As shown in FIG. 1, openings 11 a for carrying in / out the inspection object A are formed on both side surfaces of the shield box 11. The opening 11a is used to carry the inspection object A from the outside of the shield box 11 into the inside or to carry out the inspection object A from the inside of the shield box 11 to the outside. The opening 11 a is blocked by a shielding goodwill 19. The shielding goodwill 19 suppresses X-ray leakage from the inside of the shielding box 11 to the outside. The shielding goodwill 19 is formed from rubber containing lead. The shielding goodwill 19 is pushed away by the inspection object A when the inspection object A is carried in and out.

  Inside the shield box 11, a transport unit 12, an X-ray irradiator 20, a sensor unit 30, a control device 50, and the like are accommodated. A monitor 40, an input key, a power switch, and the like are disposed on the front upper portion of the shield box 11.

(2-2) Transport Unit The transport unit 12 is a belt conveyor for transporting the inspection object A so as to pass through the inside of the shield box 11. As shown in FIG. 1, the transport unit 12 is disposed so as to penetrate through the openings 11 a formed on both side surfaces of the shield box 11.

  The transport unit 12 mainly includes a conveyor motor 12a, an encoder 12b, a conveyor roller 12c, and an endless belt 12d. The conveyor roller 12c is driven by the conveyor motor 12a. By driving the conveyor roller 12c, the belt 12d rotates, and the inspection object A on the belt 12d is conveyed. In FIG. 3, the conveyance direction of the inspection object A is indicated by an arrow.

  The conveyance speed of the inspection object A by the conveyance unit 12 varies depending on the set speed input by the operator of the X-ray inspection apparatus 10. The control device 50 performs inverter control of the conveyor motor 12a based on the set speed, and finely controls the conveyance speed of the inspection object A. The encoder 12 b of the transport unit 12 detects the transport speed of the inspection object A and transmits it to the control device 50.

  In addition, although the conveyance unit 12 uses the belt conveyor as a conveyance mechanism, you may use a top chain conveyor, a rotary table, etc. as a conveyance mechanism instead of a belt conveyor.

(2-3) X-ray irradiator The X-ray irradiator 20 irradiates the inspection object A transported by the transport unit 12 to a predetermined position inside the shield box 11 with X-rays. The X-rays emitted from the X-ray irradiator 20 include X-rays of various energies.

  As shown in FIG. 3, the X-ray irradiator 20 is disposed above the transport unit 12. The X-ray irradiator 20 irradiates a fan-shaped X-ray (radiated light) toward the sensor unit 30 disposed below the transport unit 12. As shown in FIG. 3, the X-ray irradiation range X is perpendicular to the transport surface of the transport unit 12 and extends in a direction orthogonal to the transport direction of the inspection object A by the transport unit 12. . That is, the X-rays emitted from the X-ray irradiator 20 spread in the width direction of the belt 12d.

(2-4) Sensor unit The sensor unit 30 is a sensor that detects X-rays emitted from the X-ray irradiator 20. Specifically, the sensor unit 30 detects transmitted X-rays that are X-rays transmitted through the inspection object A transported by the transport unit 12.

  As shown in FIG. 3, the sensor unit 30 is disposed below the transport unit 12. The sensor unit 30 mainly includes a low energy line sensor (first sensor) 31, a high energy line sensor (second sensor) 32, and a filter 33. The low energy line sensor 31, the filter 33, and the high energy line sensor 32 are arranged in this order from the side closer to the X-ray irradiator 20. That is, the filter 33 is disposed between the low energy line sensor 31 and the high energy line sensor 32. Hereinafter, the low energy line sensor 31 and the high energy line sensor 32 are collectively referred to as line sensors 31 and 32 as necessary.

  The low energy line sensor 31 and the high energy line sensor 32 are each composed of a plurality of X-ray detection elements. The plurality of X-ray detection elements are horizontally arranged in a straight line along a direction (width direction of the belt 12d) orthogonal to the conveyance direction of the inspection object A by the conveyance unit 12.

  FIG. 4 is a schematic diagram showing details of the sensor unit 30. Hereinafter, the X-rays emitted from the X-ray irradiator 20 include X-rays in a low energy band (first energy band), X-rays in a medium energy band, and X-rays in a high energy band (second energy band). Are included. The X-ray in the medium energy band is an X-ray in the energy band between the X-ray in the low energy band and the X-ray in the high energy band. In FIG. 4, the symbol X1 represents the X-ray in the low energy band, the symbol X2 represents the X-ray in the medium energy band, and the symbol X3 represents the X-ray in the high energy band.

  The low energy line sensor 31 absorbs and detects low energy X-rays. Medium energy band X-rays and high energy band X-rays pass through the low energy line sensor 31. The filter 33 absorbs X-rays in the medium energy band that has passed through the low energy line sensor 31. High energy X-rays pass through the filter 33. The high energy line sensor 32 absorbs and detects high energy band X-rays transmitted through the low energy line sensor 31 and the filter 33. The filter 33 absorbs X-rays in the medium energy band, thereby preventing the medium energy band X-rays from being absorbed by the high energy line sensor 32.

  The sensor unit 30 detects transmitted X-rays and outputs an X-ray transmitted signal indicating a voltage corresponding to the detected intensity of the transmitted X-rays. As will be described later, the X-ray transmission signal is used to generate a transmission image of the inspection object A. FIG. 5 is a graph showing an example of the intensity of transmitted X-rays detected by the low energy line sensor 31 and the high energy line sensor 32 of the sensor unit 30. The horizontal axis of the graph represents the position on each line sensor 31, 32. The vertical axis of the graph represents the intensity of transmitted X-rays detected by the line sensors 31 and 32. In FIG. 5, the symbol D <b> 1 represents the intensity of transmitted X-rays detected by the low energy line sensor 31, and the symbol D <b> 2 represents the intensity of transmitted X-rays detected by the high energy line sensor 32. In the transmission image of the inspection object A, a portion with a large amount of transmitted X-ray detection is displayed bright (high brightness), and a portion with a small amount of transmission X-ray detection is displayed dark (low luminance). That is, the brightness (brightness value) of the transmission image of the inspection object A depends on the detected amount of transmitted X-rays. As shown in FIG. 5, the detected amount of X-rays that have passed through the inspection object A is lower than the detected amount of X-rays that did not pass through the inspection object A.

  Furthermore, the sensor unit 30 also functions as a sensor for detecting the timing when the inspection object A passes through the X-ray fan-shaped irradiation range X (see FIG. 3). That is, when the inspection object A conveyed on the belt 12d of the conveyance unit 12 comes to a position above the sensor unit 30 (a position overlapping the irradiation range X), the sensor unit 30 applies a voltage equal to or lower than a predetermined threshold value. An X-ray transmission signal (first signal) is output. On the other hand, when the inspection object A passes the irradiation range X, the sensor unit 30 outputs an X-ray transmission signal (second signal) indicating a voltage exceeding a predetermined threshold. By sending the first signal and the second signal to the control device 50, the presence or absence of the inspection object A in the irradiation range X is detected.

(2-5) Monitor The monitor 40 is a liquid crystal display with a touch panel function. The monitor 40 functions as a display unit and an input unit of the X-ray inspection apparatus 10. On the monitor 40, the inspection result of the inspection object A is displayed. The monitor 40 displays a screen for inputting parameters relating to the initial settings and the quality determination of the inspection object A.

  An operator of the X-ray inspection apparatus 10 can operate the monitor 40 to input inspection parameters, operation setting information, and the like. The inspection parameter is a parameter necessary for determining the quality of the inspection object A. Specifically, the inspection parameter is a threshold value of transmitted X-ray intensity used for determining the presence or absence of foreign matter contained in the inspection object A. The operation setting information is information such as the inspection speed of the inspection object A and the transport direction of the transport unit 12.

  The monitor 40 is connected to the control device 50 and transmits and receives signals to and from the control device 50. The inspection parameters and operation setting information input by the monitor 40 are stored in the storage unit 52 of the control device 50.

(2-6) Control Device The control device 50 is mainly configured by a CPU, ROM, RAM, HDD (hard disk drive), and the like. An SSD (solid state drive) may be used instead of the HDD. The control device 50 also includes a display control circuit, an input circuit, a communication port, and the like not shown. The display control circuit is a circuit that controls display on the monitor 40. The input circuit is a circuit that captures input data input by the operator via the touch panel of the monitor 40 and input keys. The communication port is a port that enables connection with an external device such as a printer and a network such as a LAN.

  FIG. 6 is a block diagram of the control device 50. The control device 50 mainly includes a control unit 51 and a storage unit 52. The control device 50 is electrically connected to the conveyor motor 12a, the encoder 12b, the X-ray irradiator 20, the sensor unit 30, the monitor 40, and the like. The control device 50 acquires data related to the rotation speed of the conveyor motor 12a from the encoder 12b, and calculates the moving distance of the inspection object A based on the data. The control device 50 receives the X-ray transmission signal output from the sensor unit 30, and detects the timing when the inspection object A on the belt 12d of the transport unit 12 reaches the X-ray irradiation range X. The control device 50 determines the presence / absence of the foreign matter contained in the inspection object A based on the intensity of the transmitted X-ray, and determines the quality of the inspection object A.

(2-6-1) Control Unit The control unit 51 implements various functions by executing various programs stored in the storage unit 52. The control unit 51 includes an image processing unit 61, a sensor deterioration detection unit 62, and a quality determination unit 63.

(2-6-1-1) Image Processing Unit The image processing unit 61 generates a transmission image of the inspection object A based on the X-ray transmission signal output from the sensor unit 30, and performs various processes on the transmission image. Image processing is performed to generate a final image. The generated final image is used to determine the presence or absence of foreign matter contained in the inspection object A.

  The image processing unit 61 includes an image generation unit 61a, an image enlargement / reduction unit 61b, an image registration unit 61c, a histogram creation unit 61d, a histogram integration unit 61e, a luminance conversion table creation unit 61f, and an image conversion unit 61g. , A division unit 61h, a filter unit 61i, and a binarization unit 61j.

(A) Image Generation Unit The image generation unit 61a generates a transmission image of the inspection object A based on the X-ray transmission signal output from the sensor unit 30. Specifically, the image generation unit 61a is configured to receive a predetermined short time interval from each X-ray detection element of the sensor unit 30 every time the inspection object A passes through the X-ray fan-shaped irradiation range X (see FIG. 3). Data of the X-ray transmission signal output for each time is connected in a matrix in order of time to generate a transmission image of the inspection object A. The presence or absence of the inspection object A in the irradiation range X is determined by the presence or absence of a signal output from the sensor unit 30. The transmission image generated by the image generation unit 61a is stored in the image storage unit 52a.

  The transmission image generated by the image generation unit 61a includes a low energy transmission image P1 and a high energy transmission image P2. The low energy transmission image P1 is a transmission image generated based on the X-ray transmission signal (first output value) output from the low energy line sensor 31. The high energy transmission image P2 is a transmission image generated based on the X-ray transmission signal (second output value) output from the high energy line sensor 32. These transmission images are composed of a plurality of pixels arranged in a matrix. Each pixel of the transmission image has one of a plurality of density levels (brightness levels).

  FIG. 7A is an example of the low-energy transmission image P1 of the inspection object A. FIG. 7B is an example of a high-energy transmission image P2 of the inspection object A. 7A and 7B are transmission images of the inspection object A including the foreign matter M. FIG. In FIG. 7A and FIG. 7B, the density level (brightness level) of the transmission image is expressed by hatching intervals. That is, the smaller the hatching interval of a certain region, the higher the density level of the pixels constituting that region and the smaller the amount of X-ray detection. In other words, the narrower the hatching interval of a region, the lower the luminance value of the pixels constituting that region, and the darker the region. The low energy transmission image P1 has a higher contrast than the high energy transmission image P2, and is dark overall. This is because the X-rays in the low energy band are more easily absorbed by the inspection object A and the foreign matter M than the X-rays in the high energy band. Further, since the X-ray absorption rate of the inspection object A is different from the X-ray absorption rate of the foreign matter M, in the low energy transmission image P1 and the high energy transmission image P2, the density level of the region occupied by the inspection object A is This is different from the density level of the region occupied by M.

(B) Image Enlargement / Reduction Unit The image enlargement / reduction unit 61b performs a process of matching the size of the low energy transmission image P1 of the inspection object A with the size of the high energy transmission image P2 of the inspection object A. The X-ray irradiator 20 emits X-rays in a fan shape toward the sensor unit 30 (see FIG. 3). The distance from the X-ray irradiator 20 to the high energy line sensor 32 is longer than the distance from the X-ray irradiator 20 to the low energy line sensor 31. Therefore, as shown in FIG. 5, the detection area of the inspection object A of the high energy line sensor 32 is slightly wider than the detection area of the inspection object A of the low energy line sensor 31. As a result, the size of the high energy transmission image P2 of the inspection object A is slightly larger than the size of the low energy transmission image P1 of the inspection object A.

  Therefore, the image enlargement / reduction unit 61b enlarges the low energy transmission image P1 by the conversion ratio R in the longitudinal direction of the line sensors 31 and 32. The conversion ratio R is a ratio of the distance from the X-ray irradiator 20 to the high energy line sensor 32 and the distance from the X-ray irradiator 20 to the low energy line sensor 31. The image enlargement / reduction unit 61b may reduce the high energy transmission image P2 in the longitudinal direction of the line sensors 31 and 32 by the conversion ratio 1 / R.

(C) Image Alignment Unit The image alignment unit 61c performs a process of aligning the position of the low energy transmission image P1 of the inspection object A and the position of the high energy transmission image P2 of the inspection object A. The image registration unit 61c moves one of the low energy transmission image P1 and the high energy transmission image P2 so that the difference between the low energy transmission image P1 and the high energy transmission image P2 is minimized.

  Specifically, the image alignment unit 61c superimposes the two transmission images P1 and P2, calculates the sum of absolute values of the differences in luminance between the two transmission images P1 and P2 in each pixel, and the sum is Align so that it is minimized. Therefore, after the image alignment unit 61c superimposes the two transmission images P1 and P2, the positional deviation between the inspection object A and the foreign matter M in the two transmission images P1 and P2 is substantially eliminated, and the two transmission images P1. , P2 the absolute value of the difference in luminance is close to zero. Therefore, since the foreign matter M contained in the inspection object A cannot be substantially determined, the foreign matter M contained in the inspection object A can be obtained by performing image conversion processing of the low-energy transmission image P1 described below. It is possible to determine.

(D) Histogram Creation Unit The histogram creation unit 61d creates a low energy histogram H1 indicating the luminance distribution of the low energy transmission image P1 and a high energy histogram H2 indicating the luminance distribution of the high energy transmission image P2. FIG. 8 is an example of the low energy histogram H1 and the high energy histogram H2. In FIG. 8, the horizontal axis represents the luminance value of the pixel, and the luminance value becomes smaller toward the left side, so that the pixel becomes darker. The vertical axis represents the number of pixels included in the transmission image.

  As described above, since the low energy transmission image P1 is generally darker than the high energy transmission image P2, as shown in FIG. 8, the low energy histogram H1 is compared to the high energy histogram H2. , The left side in the figure (the side where the luminance value of the pixel is small).

(E) Histogram Integration Unit The histogram integration unit 61e integrates the low energy histogram H1 to calculate the low energy histogram integration curve C1, and also integrates the high energy histogram H2 to calculate the high energy histogram integration curve C2. FIG. 9 is an example of the low energy histogram integration curve C1 and the high energy histogram integration curve C2. In FIG. 9, the horizontal axis represents the luminance value of the pixel, and the vertical axis represents the integrated value of the number of pixels included in the transmission image.

(F) Luminance Conversion Table Creation Unit The luminance conversion table creation unit 61f compares the low energy histogram integration curve C1 and the high energy histogram integration curve C2, and matches the low energy histogram integration curve C1 with the high energy histogram integration curve C2. Alternatively, a brightness conversion table to be approximated is created. The luminance conversion table is composed of the luminance conversion ratio I at each luminance value. The luminance conversion ratio I is a ratio between the integrated value I1 of the low energy histogram integrated curve C1 and the integrated value I2 of the high energy histogram integrated curve C2 (see FIG. 9).

(G) Image Conversion Unit The image conversion unit 61g performs luminance conversion of each pixel of the low energy transmission image P1 based on the luminance conversion table, and acquires the low energy transmission image P1a after luminance conversion. FIG. 7C shows a low-energy converted low-energy transmission image P1a acquired by the luminance conversion processing of the low-energy transparent image P1 in FIG.

(H) Dividing unit The dividing unit 61h performs division between the luminance value of each pixel of the low-energy transmission image P1a after luminance conversion and the luminance value of each pixel of the high-energy transmission image P2, thereby inspecting the object to be inspected. A process to erase A is performed. The division unit 61h outputs a result image having a result obtained by dividing the luminance value of each pixel of the two transmission images P1a and P2. Note that the division unit 61h, for example, multiplies the division result by 100 times in order to easily distinguish between pixels having different luminance values of the two transmission images P1a and P2 and pixels having the same luminance value of the two transmission images P1a and P2. May be.

(I) Filter unit Since the low energy transmission image P1 and the high energy transmission image P2 include random noise, the result image output from the division unit 61h also includes the random noise. The filter unit 61i uses a Gaussian filter or the like to remove random noise contained in the result image output from the division unit 61h.

(J) Binarization Unit The binarization unit 61j binarizes the result image from which random noise has been removed using a predetermined value as a threshold value. Thereby, the binarization part 61j can acquire the binarized image from which only the foreign material M was extracted, when the foreign material M is contained in the to-be-inspected object A.

  Thereafter, the image processing unit 61 superimposes the binarized image acquired by the binarizing unit 61j and the high energy transmission image P2 to generate a final image. The final image is displayed on the monitor 40. Note that the binarization unit 61j may superimpose the binarized image and the low energy transmission image P1.

(2-6-1-2) Sensor degradation detection unit The sensor degradation detection unit 62 detects degradation of the low energy line sensor 31 and the high energy line sensor 32. As the accumulated use time of the X-ray inspection apparatus 10 becomes longer, the accumulated time for which the X-ray detection elements of the line sensors 31 and 32 are irradiated with X-rays becomes longer. Since X-rays are electromagnetic waves having higher energy than visible light, the X-ray detection element gradually deteriorates as it is continuously irradiated with X-rays. Specifically, the intensity of transmitted X-rays that can be detected by the X-ray detection element is gradually reduced, so that the X-ray detection element is deteriorated. As a result, the level of the X-ray transmission signal output from the line sensors 31 and 32 gradually decreases, and the line sensors 31 and 32 deteriorate. The X-ray transmission signal output from the line sensors 31 and 32 indicates a voltage corresponding to the intensity of the transmission X-ray detected by the X-ray detection element. Therefore, the deterioration of the line sensors 31 and 32 means a decrease in this voltage.

  The sensor deterioration detection unit 62 determines whether or not the line sensors 31 and 32 have deteriorated based on the output values (X-ray transmission signal levels) of the line sensors 31 and 32. Specifically, when the sensor deterioration detection unit 62 detects that the output value (first output value) of the low energy line sensor 31 has decreased by a predetermined value or more, the low energy line sensor 31 has deteriorated. When it is detected that the output value (second output value) of the high energy line sensor 32 has decreased by a predetermined value or more, it is determined that the high energy line sensor 32 has deteriorated. As the output values of the line sensors 31 and 32, for example, a voltage corresponding to the maximum value of transmitted X-ray intensity detected by a plurality of X-ray detection elements of the line sensors 31 and 32 is used.

  The sensor deterioration detection unit 62 compares the output values of the line sensors 31 and 32 at a certain point of time with the output values of the line sensors 31 and 32 for comparison, and the output value at the certain point of time is based on the output value for comparison. Is detected to be lower than a predetermined value, it is determined that the line sensors 31 and 32 have deteriorated. As the output value for comparison, for example, an output value when the X-ray inspection apparatus 10 is used for the first time is used. In this case, the sensor deterioration detection unit 62 determines that the difference between the output values of the line sensors 31 and 32 when the X-ray inspection apparatus 10 is used for the first time and the output values of the line sensors 31 and 32 at a certain time is equal to or greater than a predetermined value. When it becomes, it determines with the line sensors 31 and 32 having deteriorated. The output values of the line sensors 31 and 32 when the X-ray inspection apparatus 10 is used for the first time are stored in the storage unit 52.

(2-6-1-3) Pass / Fail Judgment Unit The pass / fail judgment unit 63 analyzes the final image output from the image processing unit 61 and judges a pass / fail product regarding the inspection object A. The pass / fail determination unit 63 determines that the inspection object A is a non-defective product when determining that the foreign object M is not included in the inspection object A. On the other hand, when it is determined that the foreign object M is included in the inspection object A, the quality determination unit 63 determines that the inspection object A is a defective product. The pass / fail judgment unit 63 sets the object A to be inspected when a pixel region (a pixel region representing the foreign matter M) having a luminance value equal to or greater than a predetermined value is included in the final image output from the image processing unit 61. It is determined that M is included.

  When the pass / fail determination unit 63 determines whether the inspection object A is non-defective / defective, it outputs a signal regarding whether the inspection A is a non-defective / defective product. The signal output by the pass / fail determination unit 63 is sent to the distribution mechanism 70. Based on the determination result by the pass / fail determination unit 63, the distribution mechanism 70 sends the inspection object A, which is a non-defective product, to the rear conveyor 80, or distributes the inspection object A, which is a defective product, to the defective product discharge directions 90 and 91.

(2-6-2) Storage Unit The storage unit 52 stores inspection parameters, operation setting information, and various programs executed by the control unit 51. Inspection parameters and operation setting information are input by the operator using the touch panel function of the monitor 40.

  The storage unit 52 stores various data generated, acquired, or used by the image processing unit 61, the sensor deterioration detection unit 62, and the pass / fail determination unit 63. For example, the storage unit 52 calculates the low energy transmission image P1 and the high energy transmission image P2 generated by the image generation unit 61a, the low energy histogram H1 and the high energy histogram H2 generated by the histogram generation unit 61d, and the histogram integration unit 61e. Low energy histogram integration curve C1 and high energy histogram integration curve C2, the luminance conversion table created by the luminance conversion table creation unit 61f, the luminance converted low energy transmission image P1a acquired by the image conversion unit 61g, and the result output by the division unit 61h The image and the final image generated by the binarization unit 61j are stored.

  The storage unit 52 also stores an output value for comparison used by the sensor deterioration detection unit 62. The output value for comparison is, for example, the output value of the line sensors 31 and 32 when the X-ray inspection apparatus 10 is used for the first time, and is used by the sensor deterioration detection unit 62 to determine deterioration of the sensor unit 30.

(3) Image Processing by Image Processing Unit 61 Next, image processing by the image processing unit 61 will be described. This image processing is a series of processes for outputting a final image that is used by the quality determination unit 63 to determine the presence or absence of the foreign matter M included in the inspection object A. FIG. 10 is a flowchart of image processing by the image processing unit 61.

(3-1) Step S11 “Generation of Transparent Image”
First, X-rays are irradiated from the X-ray irradiator 20 to the inspection object A conveyed to a predetermined position inside the shield box 11. X-rays (transmitted X-rays) irradiated from the X-ray irradiator 20 and transmitted through the inspection object A are detected by the low energy line sensor 31 and the high energy line sensor 32 of the sensor unit 30. The image generation unit 61a generates a low energy transmission image P1 based on the X-ray transmission signal output from the low energy line sensor 31, and transmits high energy transmission based on the X-ray transmission signal output from the high energy line sensor 32. An image P2 is generated.

(3-2) Step S12 “Position / Size Adjustment of Transparent Image”
Next, the image enlargement / reduction unit 61b and the image registration unit 61c perform processing to match the positions and sizes of the low energy transmission image P1 and the high energy transmission image P2 generated in step S11. This process may be executed at once by affine transformation of the low energy transmission image P1, for example.

(3-3) Step S13 “Transmission Image Brightness Conversion”
Next, the luminance conversion processing of the low energy transmission image P1 is performed so that the luminance of each pixel of the low energy transmission image P1 and the luminance of each pixel of the high energy transmission image P2 completely or substantially coincide with each other. Do. Specifically, the image conversion unit 61g performs luminance conversion of each pixel of the low energy transmission image P1 based on the luminance conversion table created by the luminance conversion table creation unit 61f, and obtains the low energy transmission image P1a after luminance conversion. get.

  The luminance conversion table creation unit 61f creates a luminance conversion table based on the low energy histogram integration curve C1 and the high energy histogram integration curve C2 calculated by the histogram integration unit 61e. The histogram integration unit 61e calculates a low energy histogram integration curve C1 and a high energy histogram integration curve C2, respectively, based on the low energy histogram H1 and the high energy histogram H2 created by the histogram creation unit 61d.

(3-4) Step S14 “Calculation between Transparent Images”
Next, the dividing unit 61h performs division between the low-energy transmission image P1a after luminance conversion and the high-energy transmission image P2, and acquires a result image in which the difference between the transmission images P1a and P2 is extracted. . Specifically, the dividing unit 61h extracts the difference by dividing the luminance value of each pixel of the two transmission images P1a and P2.

(3-5) Step S15 “Noise Removal”
Next, the filter unit 61i removes random noise from the result image acquired in step S14, and performs luminance conversion processing so that the luminance value of the pixel area other than the pixel area occupied by the foreign matter M becomes substantially zero. Do.

(3-6) Step S16 “binarization”
Next, the binarization unit 61j binarizes the result image from which random noise has been removed in step S15 with a predetermined value as a threshold, and obtains a binarized image from which only the foreign matter M has been extracted.

  Finally, the image processing unit 61 superimposes the binarized image and the high energy transmission image P2 and outputs a final image in which the foreign matter M included in the inspection object A is extracted.

(4) Features (4-1)
The X-ray inspection apparatus 10 of this embodiment inspects the inspection object A using the low energy line sensor 31 and the high energy line sensor 32. These line sensors 31 and 32 respectively detect two types of transmitted X-rays that are irradiated from the X-ray irradiator 20 and transmitted through the inspection object A and having different energy bands. The low energy line sensor 31 detects transmitted X-rays in a low energy band, and the high energy line sensor 32 detects transmitted X-rays in a high energy band.

  The sensor deterioration detection unit 62 of the X-ray inspection apparatus 10 detects the deterioration of the line sensors 31 and 32 based on the output values of the line sensors 31 and 32. Therefore, the operator of the X-ray inspection apparatus 10 does not determine the deterioration of the line sensors 31 and 32, but the X-ray inspection apparatus 10 automatically determines the deterioration of the line sensors 31 and 32. As a result, the X-ray inspection apparatus 10 continues to be used without replacement of the line sensors 31 and 32 even though the line sensors 31 and 32 are deteriorated so as to adversely affect the inspection result of the inspection object A. In addition, it is possible to prevent the line sensors 31 and 32 from being unnecessarily replaced even though the line sensors 31 and 32 are not deteriorated so as to adversely affect the inspection result of the inspection object A. can do. Therefore, the X-ray inspection apparatus 10 can detect deterioration of the line sensors 31 and 32 at an appropriate timing. The operator of the X-ray inspection apparatus 10 can maintain the detection accuracy of the foreign matter M of the X-ray inspection apparatus 10 by replacing the line sensors 31 and 32 in which the deterioration has been detected with new ones.

(4-2)
The sensor deterioration detection unit 62 of the X-ray inspection apparatus 10 detects a decrease in the output values of the line sensors 31 and 32 and detects deterioration of the line sensors 31 and 32. FIG. 11 is a graph showing an example of a temporal change in output values of the line sensors 31 and 32. In FIG. 11, the horizontal axis represents the elapsed time from the first use of the X-ray inspection apparatus 10, and the vertical axis represents the output values of the line sensors 31 and 32. In FIG. 11, symbol L <b> 1 represents the elapsed time of the output value of the low energy line sensor 31, and symbol L <b> 2 represents the elapsed time of the output value of the high energy line sensor 32.

  As shown in FIG. 11, the output values of the line sensors 31 and 32 gradually decrease with time. Further, the distance between the X-ray irradiator 20 and the low energy line sensor 31 is shorter than the distance between the X-ray irradiator 20 and the high energy line sensor 32. Therefore, the X-ray intensity directly received by the low energy line sensor 31 from the X-ray irradiator 20 is higher than the X-ray intensity directly received by the high energy line sensor 32 from the X-ray irradiator 20. Thereby, the progress speed of deterioration of the low energy line sensor 31 tends to be larger than the progress speed of deterioration of the high energy line sensor 32. That is, the rate of decrease of the output values of the line sensors 31 and 32 is different from each other. Normally, as shown in FIG. 11, the rate of decrease of the output value of the line sensor 31 for low energy is the output value of the line sensor 32 for high energy. Greater than the rate of decline.

  The X-ray inspection apparatus 10 stores the output values of the line sensors 31 and 32 when the X-ray inspection apparatus 10 is used for the first time, and periodically compares the output values with the current output values. A decrease in output value can be detected. Specifically, the X-ray inspection apparatus 10 can detect that the output values of the line sensors 31 and 32 have decreased by a predetermined value or more than when the X-ray inspection apparatus 10 is used. The X-ray inspection apparatus 10 detects the deterioration of the line sensors 31 and 32 when the output values of the line sensors 31 and 32 are decreased by a predetermined value or more. Thereby, the X-ray inspection apparatus 10 can detect the deterioration of the line sensors 31 and 32 at an appropriate timing.

(5) Modifications One embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the invention.

(5-1) Modification A
In the embodiment, the X-ray inspection apparatus 10 detects a decrease in the output values of the line sensors 31 and 32 to detect deterioration of the line sensors 31 and 32. Specifically, the sensor deterioration detection unit 62 determines that the line sensors 31 and 32 have deteriorated when the output values of the line sensors 31 and 32 have decreased by a predetermined value or more.

  However, the sensor deterioration detection unit 62 may detect a decrease in the output value of only one of the low energy line sensor 31 and the high energy line sensor 32 and detect the deterioration of only one of the line sensors. In this case, when the operator of the X-ray inspection apparatus 10 detects, for example, deterioration of one of the low energy line sensor 31 and the high energy line sensor 32, both of the line sensors 31 and 32 are replaced with new ones. It is preferable to exchange. By replacing both line sensors 31 and 32 with new ones, the difference in the degree of deterioration of the line sensors 31 and 32 is always predetermined as compared with the case where only the line sensors 31 and 32 in which deterioration has been detected are replaced with new ones. It can be suppressed below the level. In other words, it is possible to avoid a situation in which one of the line sensors 31 and 32 is new and hardly deteriorated, but the other is considerably deteriorated. If the difference in the degree of deterioration of the line sensors 31 and 32 is large, the detection accuracy of the foreign matter M may be adversely affected. Accordingly, the detection accuracy of the foreign matter M of the X-ray inspection apparatus 10 can be maintained by exchanging both the line sensors 31 and 32 with new ones.

  In this modification, it is preferable that the sensor deterioration detection unit 62 detects the output value of only the low energy line sensor 31 and detects the deterioration of only the low energy line sensor 31. This is because, as described above, the low energy line sensor 31 is more likely to deteriorate because it is closer to the X-ray irradiator 20 than the high energy line sensor 32. In this case, when the deterioration of the line sensor 31 for low energy is detected, the difference in the degree of deterioration of the line sensors 31, 32 is always set to a predetermined level by replacing both line sensors 31, 32 with new ones. Since it can be suppressed to the following, the detection accuracy of the foreign matter M of the X-ray inspection apparatus 10 can be maintained.

(5-2) Modification B
In the embodiment, the sensor deterioration detection unit 62 determines that the line sensors 31 and 32 have deteriorated when the output values of the line sensors 31 and 32 have decreased by a predetermined value or more. However, when the difference between the output value of the low energy line sensor 31 and the output value of the high energy line sensor 32 exceeds a predetermined value, the sensor deterioration detection unit 62 deteriorates the line sensors 31 and 32. May be detected.

  FIG. 11 shows an example of the difference D between the output values of both line sensors 31 and 32. As described above, the decreasing speeds of the output values of both line sensors 31 and 32 are different from each other. Specifically, the rate of decrease of the output value of the low energy line sensor 31 is usually greater than the rate of decrease of the output value of the high energy line sensor 32. Therefore, the difference between the output values of both line sensors 31, 32 gradually increases. As the difference between the output values of both line sensors 31 and 32 gradually increases, the difference in luminance value between the low-energy transmission image P1a after luminance conversion and the high-energy transmission image P2 when the same luminance conversion table is continuously used. Tend to be larger. As a result, the final image generated by the image processing unit 61 may include a pixel region other than the pixel region representing the foreign matter M, and the detection accuracy of the foreign matter M of the X-ray inspection apparatus 10 is lowered. Therefore, the difference between the output values of both line sensors 31 and 32 can be used as an indicator of the degree of deterioration of the line sensors 31 and 32.

  Therefore, in this modification, the X-ray inspection apparatus 10 determines the deterioration based on the difference between the output values of the two line sensors 31 and 32 when the deterioration speeds of the two line sensors 31 and 32 are different. The deterioration of the sensors 31 and 32 can be detected appropriately.

(5-3) Modification C
In the embodiment, the image conversion unit 61g, which is one function of the control device 50, completely or substantially has the luminance of each pixel of the low energy transmission image P1 and the luminance of each pixel of the high energy transmission image P2. The luminance conversion of the low energy transmission image P1 is performed so as to match. The image conversion unit 61g performs luminance conversion of the low energy transmission image P1 based on the luminance conversion table generated by the luminance conversion table generation unit 61f, and acquires the low energy transmission image P1a after luminance conversion. The low energy transmission image P1 is an image obtained from the output value of the low energy line sensor 31, and the high energy transmission image P2 is an image obtained from the output value of the high energy line sensor 32.

  However, the sensor deterioration detection unit 62 may further perform processing for converting the output value of the low energy line sensor 31 based on the luminance conversion table. Thus, the output value of the low energy line sensor 31 is converted so that the output value of the low energy line sensor 31 and the output value of the high energy line sensor 32 are completely or substantially coincident with each other. The In this case, the sensor deterioration detection unit 62 has a difference between the output value of the low energy line sensor 31 converted based on the luminance conversion table and the output value of the high energy line sensor 32 being a predetermined value or more. When this is detected, the deterioration of the line sensors 31 and 32 can be detected. This is because, when the same luminance conversion table is continuously used, the difference between the output values of both line sensors 31, 32 gradually increases due to the difference in the deterioration speed of both line sensors 31, 32. Accordingly, the X-ray inspection apparatus 10 can appropriately detect the deterioration of the line sensors 31 and 32 even when the deterioration speeds of both the line sensors 31 and 32 are different.

  In this modification, the sensor deterioration detection unit 62 is configured so that the output value of the low energy line sensor 31 and the output value of the high energy line sensor 32 are completely or substantially coincident with each other. The output value of the energy line sensor 32 may be converted.

(5-4) Modification D
In the modification C, the sensor deterioration detection unit 62 further performs a process of converting the output value of the low energy line sensor 31 based on the luminance conversion table. However, the sensor deterioration detection unit 62 may automatically update the luminance conversion table used for this conversion process, and may suggest the operator of the X-ray inspection apparatus 10 to update the luminance conversion table. .

  For example, the sensor deterioration detection unit 62 may automatically update the luminance conversion table periodically, or may automatically update the luminance conversion table every time the inspection of the inspection object A is performed a predetermined number of times. Good. Moreover, the sensor deterioration detection part 62 may display the content which requests | requires permission of the update work of a brightness | luminance conversion table on the monitor 40 instead of updating a brightness | luminance conversion table automatically.

(5-5) Modification E
In the modification C, the sensor deterioration detection unit 62 may periodically and automatically update the luminance conversion table used for the process of converting the output value of the low energy line sensor 31. In this case, the sensor deterioration detection unit 62 calculates the luminance conversion table based on the output values of both the line sensors 31 and 32 obtained when the pass / fail determination unit 63 determines the pass / fail product regarding the inspection object A. You may update automatically.

  Specifically, the sensor deterioration detection unit 62 adjusts the output values of both line sensors 31 and 32 based on the output values of both line sensors 31 and 32 obtained by the normal inspection of the inspection object A. The brightness conversion table used is automatically updated. Therefore, the sensor deterioration detection unit 62 can maintain the brightness conversion table in an optimum state by simply using the X-ray inspection apparatus 10 for the inspection of the inspection object A, so that the line sensors 31 and 32 are deteriorated. Can be detected appropriately. Note that the probability that the foreign object M is contained in the inspection object A is usually very low. Therefore, if the luminance conversion table is updated based on the inspection results of a sufficiently large number of inspection objects A, the line for low energy is used. It is possible to create a luminance conversion table in which the output value of the sensor 31 and the output value of the high energy line sensor 32 are completely or substantially coincided with each other. Therefore, the above method is effective as a method for updating the luminance conversion table.

  Note that the X-ray inspection apparatus 10 may update the luminance conversion table based only on the inspection result of the inspection object A that has already been determined to be non-defective. Further, if necessary, the X-ray inspection apparatus 10 uses both the luminance conversion table currently used and the luminance conversion table newly acquired based on the inspection result of the inspection object A, The inspection result may be compared by performing a foreign matter mixing inspection of the inspection object A. In this case, for example, when the pixel area of the foreign matter M included in the final image is clearer using the newly acquired luminance conversion table, the X-ray inspection apparatus 10 is newly acquired. The brightness conversion table may be adopted in the future.

(5-6) Modification F
The control unit 51 of the X-ray inspection apparatus 10 further includes a function of a notification unit that notifies information related to the deterioration of the line sensors 31 and 32 when the sensor deterioration detection unit 62 detects the deterioration of the line sensors 31 and 32. Also good. For example, the notification unit displays a warning on the monitor 40 for notifying the operator of the X-ray inspection apparatus 10 that the line sensors 31 and 32 have deteriorated. Thereby, the X-ray inspection apparatus 10 can prompt the operator to replace the line sensors 31 and 32 at an appropriate time.

(5-7) Modification G
In the embodiment, the sensor deterioration detection unit 62 detects the deterioration of the line sensors 31 and 32 when the output values of the line sensors 31 and 32 are decreased by a predetermined value or more. However, the sensor deterioration detection unit 62 may detect the deterioration of the line sensors 31 and 32 when the output values of the line sensors 31 and 32 are decreased by a predetermined rate. For example, the sensor deterioration detection unit 62 compares the output values of the line sensors 31 and 32 at the start of use of the X-ray inspection apparatus 10 when the current output value decreases by 20% or more. You may detect degradation of.

(5-8) Modification H
In the embodiment, the sensor deterioration detection unit 62 detects the deterioration of the line sensors 31 and 32 based on the output values of the line sensors 31 and 32. However, the sensor deterioration detection unit 62 may detect the deterioration of the line sensors 31 and 32 using data generated based on these output values instead of the output values of the line sensors 31 and 32. For example, the sensor deterioration detection unit 62 may use the luminance value of the low energy transmission image P1 instead of the output value of the low energy line sensor 31, and the high energy transmission instead of the output value of the high energy line sensor 32. The luminance value of the image P2 may be used. In this case, for example, the sensor deterioration detection unit 62 detects the deterioration of the line sensors 31 and 32 when the maximum luminance values of the low energy transmission image P1 and the high energy transmission image P2 are reduced by a predetermined value or more. Also good.

(5-9) Modification I
In the embodiment, the control unit 51 of the X-ray inspection apparatus 10 includes a sensor deterioration detection unit 62, and the sensor deterioration detection unit 62 detects deterioration of the line sensors 31 and 32. However, the X-ray inspection apparatus 10 may further include a communication unit for transmitting information regarding deterioration of the line sensors 31 and 32 to the server. Thereby, a person in charge managing a plurality of X-ray inspection apparatuses 10 in a large-scale factory or the like can check deterioration information of the line sensors 31 and 32 of each X-ray inspection apparatus 10 from the terminal. In addition, by sharing the deterioration information with the support department of the manufacturer of the X-ray inspection apparatus 10, it becomes possible to replace parts before the line sensors 31 and 32 break down due to deterioration, and downtime of equipment due to the failure. Can be shortened.

  Since the X-ray inspection apparatus according to the present invention can appropriately detect the deterioration of the sensor, it is useful as an X-ray inspection apparatus that can suppress a decrease in the accuracy of inspection of the inspection object.

10 X-ray inspection equipment 20 X-ray irradiator (X-ray source)
31 Low energy line sensor (first sensor)
32 High energy line sensor (second sensor)
52 storage unit 61g image conversion unit (conversion unit)
62 Sensor deterioration detector (detector)
63 Pass / fail judgment part (inspection part)
A inspection object

Japanese Patent Laid-Open No. 10-318943

Claims (8)

An X-ray source for irradiating the inspection object with X-rays;
A first sensor that detects X-rays in a first energy band irradiated from the X-ray source and outputs a first output value related to the detected X-rays;
A second sensor that detects X-rays in a second energy band irradiated from the X-ray source and outputs a second output value relating to the detected X-rays;
A detection unit that detects deterioration of at least one of the first sensor and the second sensor based on at least one of the first output value and the second output value;
An X-ray inspection apparatus comprising: A storage unit for storing the first output value output from the first sensor and the second output value output from the second sensor;
In the detection unit, at least one of the first output value and the second output value has decreased by a predetermined value or more based on the first output value and the second output value stored in the storage unit. Detecting the deterioration when detecting
The X-ray inspection apparatus according to claim 1. The first sensor is disposed closer to the X-ray source than the second sensor,
The detection unit detects the deterioration based on the first output value stored in the storage unit when detecting that the first output value has decreased by a predetermined value or more.
The X-ray inspection apparatus according to claim 2. The detection unit detects the deterioration when detecting that a difference between the first output value and the second output value is equal to or greater than a predetermined value.
The X-ray inspection apparatus according to any one of claims 1 to 3. A conversion unit that executes conversion processing for converting at least one of the first output value and the second output value so that the first output value matches or approximates the second output value;
The detection unit detects the deterioration when it is detected that a difference between the first output value converted by the conversion unit and the second output value is a predetermined value or more.
The X-ray inspection apparatus according to any one of claims 1 to 4. The conversion unit automatically updates data used for the conversion process, or proposes an update of the data.
The X-ray inspection apparatus according to claim 5. An inspection unit that inspects the inspection object using the first output value and the second output value;
The conversion unit automatically updates the data based on the first output value and the second output value obtained when the inspection unit inspects the inspection object.
The X-ray inspection apparatus according to claim 6. When the detection unit detects the deterioration, further comprising a notification unit for notifying information on the deterioration;
The X-ray inspection apparatus according to any one of claims 1 to 7.

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