JP2016024096A - Inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inspection device capable of accurately inspecting a commodity irrespective of the position of the commodity in the width direction of a conveyor.SOLUTION: The present invention is an inspection device comprising a light irradiation unit 7 for irradiating a commodity G placed on a conveyor 5 and carried in a conveyance direction D with light, an image generation unit for generating the transmission image of the commodity G on the basis of the light that passed through the commodity G, and an inspection unit for inspecting the commodity G using the transmission image of the commodity G and an inspection standard, the inspection device being provided with a correction unit for correcting the transmission image or the inspection standard on the basis of the position information of the commodity G or the transmission image of the commodity G in the width direction crossing the conveyance direction D and the height information of the commodity G, thereby generating a corrected image or a corrected standard.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an inspection apparatus.

  An X-ray inspection apparatus that inspects cracks and the like of articles such as food is known. For example, in the X-ray inspection apparatus described in Patent Document 1, X-rays are irradiated by an X-ray source, which is a point light source, on an article that is placed on a conveyor and transported, and is arranged below the conveyor. X-rays that have passed through the article are detected by the line sensor. Further, an X-ray transmission image of the article is created by the control computer. In this apparatus, in order to inspect the presence / absence of cracks in the article, the perimeter and area of the binarized X-ray transmission image are compared with the reference perimeter and reference area. If the perimeter and area deviate from the range of the reference perimeter and reference area, the article is determined to be defective and is sorted by the sorting mechanism.

JP 2005-31069 A

  When an X-ray source that is a point light source and a line sensor are used as in the X-ray inspection apparatus described above, X-rays are irradiated so as to spread in the width direction of the conveyor. Therefore, the size and shape of the X-ray transmission image (specifically, the peripheral length, area, etc.) vary depending on the position of the article in the width direction of the conveyor. In particular, in the case of an article having a high height, the upper part of the article tends to have an angle with respect to the X-ray source. Therefore, the difference in position in the width direction of the conveyor greatly affects the size and shape of the X-ray transmission image.

  As described above, depending on the position of the article in the width direction of the conveyor, an accurate size and shape cannot be obtained from the X-ray transmission image, and as a result, there is a case where the comparison with respect to the reference peripheral length and the reference area is not properly performed. In that case, the presence or absence of cracks may be erroneously determined, making it difficult to perform an accurate inspection.

  An object of this invention is to provide the inspection apparatus which can test | inspect goods correctly irrespective of the position of the goods in the width direction of a conveyor.

  The present invention includes a light irradiating unit that irradiates an article that is placed on a conveyor and conveyed in the conveying direction, an image generating unit that generates a transmission image of the article based on light transmitted through the article, An inspection apparatus including an inspection unit that inspects an article using a transmission image and an inspection standard, the position information of the article or the transmission image of the article in the width direction intersecting the transport direction, and the height information of the article And a correction unit that generates a corrected image or a correction reference by correcting the transmission image or the inspection reference.

  According to this inspection apparatus, the transmission image of the article is generated by the image generation unit. Furthermore, the inspection unit corresponding to the transmission image or the article is corrected by the correction unit, and a corrected image or a correction reference is generated. The correction image or the correction reference is generated based on the position information of the article or the transmission image of the article in the width direction and the height information of the article. Then, an inspection is performed by the inspection unit using the corrected image or the correction reference obtained by the correction. As described above, the correction image or the correction reference in consideration of the position information of the article or its transmission image in the width direction and the height information of the article is used for the correction, thereby reducing the influence of the position of the article in the width direction of the conveyor. can do. Therefore, regardless of the position of the article in the width direction of the conveyor, the article can be inspected accurately in the inspection unit.

  The correction unit generates a correction reference by correcting the inspection reference based on the position information and the height information. In this case, the inspection standard is corrected by the correction unit based on the position information of the article or its transmission image in the width direction and the height information of the article. Therefore, regardless of the position of the article in the width direction of the conveyor, the correction reference, which is the corrected inspection reference, is used for correction, so that the accuracy of comparison with the transmission image is increased.

  The correction unit generates a corrected image by correcting the transmission image based on the position information and the height information. In this case, the transmission unit corrects the transmission image based on the position information of the article or its transmission image in the width direction and the height information of the article. Therefore, regardless of the position of the article in the width direction of the conveyor, the corrected image, which is a corrected transmission image, is used for correction, thereby improving the accuracy of comparison with the inspection standard.

  The inspection standard includes the standard area of the article. In this case, the inspection of the article based on the area, for example, the inspection of cracks is more accurate.

  The inspection standard includes the reference perimeter of the article. In this case, the inspection of the article based on the peripheral length, for example, the inspection of cracks is more accurate.

  The inspection standard includes a reference image of the article. In this case, the inspection of the article based on the image becomes more accurate. For example, it is possible to inspect for cracks in an article by comparing the size and shape of images. It is also possible to inspect the presence or absence of the contents of the article by comparing the shades of pixels included in the image.

  A plurality of articles are conveyed side by side in the width direction on the conveyor. In this case, a plurality of articles arranged in the width direction of the conveyor can be accurately inspected regardless of their positions. For example, the transmission image of the article placed near the end of the conveyor in the width direction is larger than the transmission image of the article placed in the center in the width direction, and may be deformed. Even in such a case, a corrected image or a correction reference is generated based on the height information of the article and the position information of the article or its transmission image in the width direction, and an inspection using the correction image or the correction reference is performed. Is called. Therefore, even for an article placed near the end in the width direction, the influence of changes in the size and shape of the transmission image is reduced, and an accurate comparison is performed.

  The correction unit increases the degree of correction of the transmission image or the inspection standard as the position of the article or the transmission image of the article indicated in the position information is outward in the width direction. It is considered that the angle with respect to the light irradiation unit increases as the position of the article or the transmission image thereof is outward in the width direction of the conveyor. The larger the angle with respect to the light irradiation unit, the larger the deformation rate of the size and shape of the transmission image. As the size of the transmission image and the deformation rate of the shape increase, the correction unit increases the degree of correction of the transmission image or the inspection standard. Inspection is performed.

  The light irradiation unit is a point light source, and the image generation unit includes a line sensor arranged in the width direction. In this case, the light is irradiated onto the fan-shaped irradiation range by the light irradiation unit and the line sensor, which are point light sources, but the article can be accurately inspected regardless of the position of the article in the width direction of the conveyor.

  According to the present invention, an article can be accurately inspected regardless of the position of the article in the width direction of the conveyor.

It is a perspective view which shows the external appearance of the X-ray inspection apparatus which concerns on one Embodiment. It is a perspective view which shows the inside of the shield box of the X-ray inspection apparatus shown in FIG. It is a control block diagram which shows the structure of the control computer with which the X-ray inspection apparatus of FIG. 1 is provided. It is a flowchart which shows the process sequence by a control computer. (A) And (b) is a figure which shows the difference in the transmission image by the difference in the position of the width direction. It is a figure which shows the relationship between the height of articles | goods, and the length of a shadow.

  Hereinafter, an embodiment will be described with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. The dimensional ratios in the drawings do not necessarily match those described.

(1) Overall Configuration An X-ray inspection apparatus 1 shown in FIG. 1 is an apparatus that performs quality inspection of a product (article) G in a production line for products such as food. The X-ray inspection apparatus 1 irradiates the product G that is continuously conveyed with X-rays, and inspects the shape of the product G based on the amount of X-ray transmitted through the product G. The shape inspection performed by the X-ray inspection apparatus 1 is, for example, a shape abnormality inspection of the product G or a shortage inspection for inspecting the presence or absence of cracks or chips. The commodity G is, for example, food in a cup such as butter, miso, yogurt or the like that is transported in a transport line for food or the like, or canned food.

  As shown in FIGS. 2 and 3, the X-ray inspection apparatus 1 includes a shield box 3, a conveyor 5, an X-ray irradiator (light irradiation unit) 7, an X-ray line sensor 9, a monitor 11, And a control computer 10.

  Inside the shield box 3, a conveyor 5, an X-ray irradiator 7, an X-ray line sensor 9, a control computer 10 and the like are accommodated. A monitor 11 is provided at the upper front of the shield box 3. As shown in FIG. 1, on both side surfaces of the shield box 3, openings 3 a for carrying the product G into the shield box 3 or carrying the product G out of the shield box 3 are provided. The opening 3a is closed by a shielding curtain (not shown) for suppressing leakage of X-rays to the outside of the shield box 3. The shielding curtain is made of, for example, rubber containing lead.

  The conveyor 5 conveys the product G in the conveyance direction D within the shield box 3. The conveyor 5 rotates the endless belt by a driving roller driven by a conveyor motor (not shown), and conveys the product G placed on the belt in the conveyance direction D. In the present embodiment, as shown in FIG. 2, a plurality of the same types of products G1, G2, G3 are arranged and conveyed in the width direction orthogonal to the conveyance direction D on the conveyor 5. The plurality of products G1, G2, and G3 are not limited to being arranged in a straight line in the width direction orthogonal to the transport direction D, and may be placed at different positions in the transport direction D.

  The X-ray irradiator 7 which is a point light source emits X-rays from an emission point 7a (see FIG. 5). The X-ray irradiator 7 is disposed above the conveyor 5 and irradiates the fan-shaped irradiation range X with X-rays toward the X-ray line sensor 9 disposed below the conveyor 5.

  The X-ray line sensor 9 detects X-rays. The X-ray line sensor 9 is disposed below the conveyor 5 and detects X-rays that have passed through the product G and / or the conveyor 5. As shown in FIG. 2, the X-ray line sensor 9 is configured by pixel sensors 9 a arranged in a straight line along the width direction of the conveyor 5 orthogonal to the transport direction D of the conveyor 5. The X-ray line sensor 9 detects the X-rays that are irradiated to the fan-shaped irradiation range X extending in the width direction and transmitted through the product G and / or the conveyor 5. The X-ray line sensor 9 outputs an X-ray transmission image signal indicating the amount of X-ray transmission detected by the pixel sensor 9 a to the image generation unit 21.

  The monitor 11 is a liquid crystal display. The monitor 11 displays a screen that prompts the operator to input initial settings and inspection parameters used during the inspection. The monitor 11 has a touch panel function, and accepts input of inspection parameters used at the time of initial setting and inspection by an operator. Further, the monitor 11 displays an X-ray transmission image 40 (see FIG. 5) of the product G, or displays an inspection result (shape inspection result) of the product G.

(2) Configuration of Control Computer The control computer 10 is a part that controls various operations in the X-ray inspection apparatus 1, and is configured by a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. The As shown in FIG. 3, the control computer 10 includes an image generation unit 21, a feature amount calculation unit 22, a position detection unit 23 as a conceptual part that executes various control processes in the X-ray inspection apparatus 1, The correction factor calculation unit 24, the reference value correction unit 25, and the inspection unit 26 are included. Such a conceptual part can be configured as software that is executed by the CPU after a program stored in the ROM is loaded onto the RAM, for example. The control computer 4 may be configured as hardware such as an electronic circuit. Further, the control computer 10 has a storage unit 30 including a height storage unit 31 and a reference value storage unit 32.

(2-1) Image Generation Unit The image generation unit 21 is a part that generates an X-ray transmission image 40 of the product G based on the X-rays that have passed through the product G. Specifically, the image generation unit 21 generates an X-ray transmission image 40 related to the product G as shown in FIG. 5 based on detection signals continuously transmitted from the X-ray line sensor 9. When a plurality of products G (for example, products G1, G2, G3 shown in FIG. 2) are placed in the width direction of the conveyor 5 orthogonal to the conveyance direction D, the X-ray transmission image 40 is placed on these products G. A plurality of corresponding X-ray transmission images 41, 42 (see FIG. 5) are included. Note that the shading per pixel in the X-ray transmission image 40 indicates the X-ray transmission amount of the product G corresponding thereto.

  The image generation unit 21 may perform binarization processing on the generated X-ray transmission image 40. In this case, the image generation unit 21 performs binarization processing on the X-ray transmission image 40 to divide the X-ray transmission image 40 into a background portion and a portion other than the background. The image generation unit 21 performs binarization processing on the X-ray transmission image 40 when the inspection reference used for the inspection is the reference area of the product G and / or the reference perimeter of the product G. By performing binarization processing, the image generation unit 21 converts portions other than the background as X-ray transmission images (X-ray transmission images 41, 42 and the like (see FIG. 5)) corresponding to the products G1, G2, and G3. Generate.

(2-2) Feature Quantity Calculation Unit The feature quantity calculation unit 22 is a part that calculates the feature quantity of the X-ray transmission image corresponding to each product G. The feature amount calculation unit 22 is based on the X-ray transmission image 40 generated by the image generation unit 21 or the X-ray transmission image 40 generated by the image generation unit 21 and binarized, and then the products G1, G2, X-ray transmission images corresponding to G3 (X-ray transmission images 41, 42, etc. (see FIG. 5)) are detected, and feature amounts of the respective X-ray transmission images are calculated.

  Examples of the feature amount include the area of each X-ray transmission image and / or the perimeter of each X-ray transmission image 41, 42 or the like. When the area is used as the feature amount, the feature amount calculation unit 22 counts the total number of pixels in each of the X-ray transmission images corresponding to the products G1, G2, and G3. When the perimeter is used as the feature amount, the feature amount calculation unit 22 counts the number of pixels in the peripheral portion in each of the X-ray transmission images corresponding to the products G1, G2, and G3. The feature amount is used for comparison in the inspection unit 26 described later.

(2-3) Position detection part The position detection part 23 is a part which detects the position in the width direction of the conveyor 5 of each X-ray transmissive image corresponding to goods G1, G2, G3. The position detection unit 23 detects the position in the width direction of the conveyor 5 for each X-ray transmission image detected by the feature amount calculation unit 22. Here, the position in the width direction is a distance in the width direction of each X-ray transmission image corresponding to each product G1, G2, G3, with a predetermined position in the width direction of the conveyor 5 as a reference position.

  More specifically, the position detector 23 in the obtained X-ray transmission image 40 has pixels (corresponding to a perpendicular line dropped from the emission point 7a of the X-ray irradiator 7 to the line sensor surface 9b (see FIG. 5) ( 5 (a) (hereinafter referred to as the center pixel) can be recognized. The position detection unit 23 detects the distance in the width direction of the pixels constituting each X-ray transmission image using the position of the center pixel as a reference position. The position detection unit 23 may detect the distance in the width direction for all of the pixels constituting each X-ray transmission image, or detect the distance in the width direction for a part of the pixels constituting each X-ray transmission image. May be. For example, the position detection unit 23 detects the distance (position) of the pixel having the largest distance in the width direction from the center pixel among the pixels constituting each X-ray transmission image. The position detection unit 23 generates position information indicating the position (pixel position) in the width direction of each detected X-ray transmission image.

(2-4) Correction Rate Calculation Unit The correction rate calculation unit 24 is a part that calculates a correction rate with respect to an inspection standard used for inspection. The correction factor calculation unit 24 uses each X-ray transmission image based on the position information of each X-ray transmission image generated by the position detection unit 23 and the height information of the product G stored in the height storage unit 31. A correction factor corresponding to is calculated. The correction factor calculated by the correction factor calculator 24 is 1 or more. The correction rate calculation unit 24 increases the correction rate as the position of each X-ray transmission image indicated by the position information is outward in the width direction, that is, as the pixel of each X-ray transmission image is farther from the center pixel. (Ie, increase the degree of correction). The correction rate calculation unit 24 increases the correction rate (that is, increases the degree of correction) as the height of each product G indicated in the height information is higher.

(2-5) Reference Value Correction Unit The reference value correction unit 25 is a part that corrects the inspection standard used for the inspection. The reference value correction unit 25 acquires the inspection standard corresponding to the product G stored in the reference value storage unit 32, and multiplies the inspection standard by the correction rate calculated by the correction rate calculation unit 24, thereby obtaining the inspection standard. Correct. The reference value correction unit 25 generates a correction reference that is a corrected inspection reference. As described above, since the correction factor is 1 or more, the correction reference generated by the reference value correction unit 25 is the same as or larger than the inspection reference.

  The correction factor calculation unit 24 and the reference value correction unit 25 constitute the correction unit 28 of the control computer 10. As described above, the correction unit 28 corrects the inspection standard based on the position information of the X-ray transmission image of the product G in the width direction of the conveyor 5 and the height information of the product G. The correction unit 28 generates a correction reference by correcting the inspection reference.

(2-6) Inspection Part The inspection part 26 is a part that inspects the shape of the product G. The inspection unit 26 inspects the shape of the products G1, G2, and G3 by comparing the corrected reference that is the corrected inspection standard and the feature amount of each X-ray transmission image corresponding to the products G1, G2, and G3. To do. The inspection unit 26 determines whether or not the feature amount of each X-ray transmission image is within the range of the reference value based on the correction reference. The range of the reference value based on the correction reference is set to a predetermined numerical range with respect to the correction reference. The inspection unit 26 determines whether or not the feature amount of each X-ray transmission image is within the range of the reference value. If the inspection unit 26 determines that the feature amount is within the range of the reference value, The result “pass” is output. The inspection unit 26 determines whether or not the feature amount of each X-ray transmission image is within the range of the reference value. If the inspection unit 26 determines that the feature amount is outside the range of the reference value, The result “fail” is output. When it is determined that the feature amount is outside the range of the reference value, the product G corresponding to the X-ray transmission image is sorted by the sorting mechanism.

(2-7) Height Storage Unit The height storage unit 31 of the storage unit 30 stores the height information of the product G. The height information of the product G includes the height or thickness of the product G (that is, the height from the conveyor surface 5b when the product G is placed on the conveyor 5 in a predetermined direction). The product G to be inspected by the X-ray inspection apparatus 1 includes a plurality of types of products G. The height storage unit 31 stores height information for each product G. When initial setting or the like is performed by the operator using the touch panel or the like of the monitor 11, a specific type of product G is input, and height information of the product G is read from the height storage unit 31.

(2-8) Reference Value Storage Unit The reference value storage unit 32 of the storage unit 30 stores an inspection standard corresponding to the product G. The reference value storage unit 32 stores, for example, a reference area of the product G and / or a reference perimeter of the product G as an inspection reference. The reference area and the reference perimeter are, for example, the area and perimeter of the X-ray transmission image detected by the line sensor surface 9b when the product G is placed on the central pixel of the X-ray line sensor 9. . In other words, the reference area and the reference perimeter are the area and perimeter of the X-ray transmission image detected by the line sensor surface 9b when the product G is placed immediately below the emission point 7a of the X-ray irradiator 7. They are the area and perimeter of the X-ray transmission image 41 shown in FIG. Since the line sensor surface 9b is further away from the X-ray irradiator 7 than the conveyor surface 5b, the reference area and the reference peripheral length are larger than the area and peripheral length when the product G is projected onto the conveyor surface 5b. .

  The product G to be inspected by the X-ray inspection apparatus 1 includes a plurality of types of products G. The reference value storage unit 32 stores the inspection standard for each product G. When initial setting or the like is performed by the operator using the touch panel or the like of the monitor 11, a specific type of product G is input, and the inspection standard of the product G is read from the reference value storage unit 32.

(3) Inspection Method With reference to FIG. 4, an inspection processing procedure (inspection method for the product G by the X-ray inspection apparatus 1) executed by the control computer 10 will be described. First, using the touch panel of the monitor 11, initial setting, input of inspection parameters, and the like are performed by an operator. With the plurality of products G placed on the conveyor 5, these products G are transported in the transport direction D. The X-ray irradiator 7 emits X-rays, and the X-ray line sensor 9 detects X-rays that have passed through the product G and / or the conveyor 5.

  The image generation unit 21 generates an X-ray transmission image 40 of the product G based on the X-rays transmitted through the product G (step S01). Since a plurality of products G (for example, products G1, G2, G3 shown in FIG. 2) are placed in the width direction of the conveyor 5, the X-ray transmission image 40 is a plurality of X-ray transmission images corresponding to these products G. 41, 42, etc. (see FIG. 5). The image generation unit 21 performs binarization processing on the X-ray transmission image 40 to divide the X-ray transmission image 40 into a background portion and a portion other than the background.

  Subsequently, based on the binarized X-ray transmission image 40, the feature amount calculation unit 22 generates X-ray transmission images (X-ray transmission images 41, 42, etc. (see FIG. 5) corresponding to the products G1, G2, and G3). ) And the feature amount of each X-ray transmission image is calculated (step S02). More specifically, the feature amount calculation unit 22 calculates the area of each X-ray transmission image and / or the perimeter of each X-ray transmission image 41, 42, etc. as the feature amount.

  Subsequently, the position detection unit 23 detects the position in the width direction of the conveyor 5 for each X-ray transmission image detected by the feature amount calculation unit 22 (step S03). For example, the position detection unit 23 detects the distance (position) of the pixel having the largest distance in the width direction from the center pixel among the pixels constituting each X-ray transmission image. In the example shown in FIG. 5B, the points P1a and P1b at both ends in the width direction of the X-ray transmission image 41 correspond to the pixel having the longest distance from the center pixel. An end point P2 on the outer side in the width direction of the X-ray transmission image 42 corresponds to a pixel having the longest distance from the center pixel. The position detection unit 23 generates position information indicating the position (pixel position) in the width direction of each detected X-ray transmission image.

  Subsequently, the correction rate calculation unit 24 determines each X-ray based on the position information of each X-ray transmission image generated by the position detection unit 23 and the height information of the product G stored in the height storage unit 31. A correction factor corresponding to the line transmission image is calculated (step S04). The correction factor calculated by the correction factor calculator 24 is 1 or more. The correction rate calculation unit 24 increases the correction rate (that is, increases the degree of correction) as the position of each X-ray transmission image indicated by the position information is outward in the width direction. The correction rate calculation unit 24 increases the correction rate (that is, increases the degree of correction) as the height of each product G indicated in the height information is higher.

  This correction factor is calculated based on the reference area of the product G and / or the reference perimeter of the product G stored in the reference value storage unit 32 based on the position in the width direction of each X-ray transmission image and the height of each product G. This is a numerical value for enlargement correction. For example, in the example shown in FIG. 5A, since the product G1 is placed on the central pixel of the X-ray line sensor 9, the area of the X-ray transmission image 41 of the product G1 is substantially equal to the reference area. The perimeter of the X-ray transmission image 41 of the product G1 is substantially equal to the reference perimeter. On the other hand, the product G <b> 2 placed near the end in the width direction of the conveyor 5 is out of the central pixel of the X-ray line sensor 9. Therefore, the X-ray transmission image 42 is deformed and is larger than the X-ray transmission image 41. The area of the X-ray transmission image 42 of the product G2 is larger than the reference area. The perimeter of the X-ray transmission image 42 of the product G2 is larger than the reference perimeter.

  As shown in FIG. 5A, the height dimension of the X-ray inspection apparatus 1 (distance H1 from the emission point 7a to the conveyor surface 5b and distance H2 from the conveyor surface 5b to the line sensor surface 9b), From the position in the width direction of the X-ray transmission image (distance W from the center pixel to the end point P2 of the X-ray transmission image 42), the X-ray irradiated to the upper end of the product G2 from the emission point 7a with respect to the line sensor surface 9b The angle θ is determined.

Further, as shown in FIG. 6, the shadow length w of the X-ray transmission image 42 is obtained from the height h1 of the product G and the above-described distance H2 by the trigonometric function of the angle θ. Specifically, the shadow length w is obtained by the following equation (1).
Shadow length w = (height h1 + distance H2) / tan θ (1)

  As described above, the area of the X-ray transmission image and the enlargement ratio of the peripheral length (see FIGS. 5A and 5B) due to the position of the product G in the width direction and the height h1 of the product G In consideration of the shadow length w to be corrected, the correction factor calculation unit 24 calculates a correction factor corresponding to each X-ray transmission image. A correction rate larger than 1 is calculated for the X-ray transmission image 42 shown in FIG. 5B, but the correction rate is 1 for the X-ray transmission image 41 shown in FIG. It can be.

  Subsequently, the reference value correction unit 25 is a part that corrects the inspection standard used for the inspection. The reference value correction unit 25 acquires the inspection standard corresponding to the product G stored in the reference value storage unit 32, and multiplies the inspection standard by the correction rate calculated by the correction rate calculation unit 24, thereby obtaining the inspection standard. Is corrected (step S05). The reference value correction unit 25 enlarges and corrects the reference area of the product G and / or the reference perimeter of the product G by multiplying the inspection standard by a correction factor of 1 or more. The reference value correction unit 25 generates a correction reference that is a corrected inspection reference.

  Subsequently, the inspection unit 26 determines whether or not the feature amount of each X-ray transmission image is within a reference value range based on the correction reference generated by the reference value correction unit 25 (step S06). In this way, the inspection unit 26 compares the correction reference generated by the reference value correction unit 25 with the feature amounts of the respective X-ray transmission images corresponding to the products G1, G2, and G3, thereby obtaining the product G1, Inspect the shapes of G2 and G3.

  If it is determined in step S06 that the feature quantity of a certain X-ray transmission image is within the range of the reference value based on the correction reference generated by the reference value correction unit 25 (step S06; YES), the inspection unit 26 For example, a signal indicating the inspection result “pass” for the product G corresponding to the X-ray transmission image is output to the monitor 11 (step S07). On the other hand, if it is determined in step S06 that the feature value of a certain X-ray transmission image is outside the range of the reference value based on the correction reference generated by the reference value correction unit 25 (step S06; NO), the inspection unit 26 Then, a signal indicating the inspection result “fail” for the product G corresponding to the X-ray transmission image is output to, for example, the monitor 11 (step S08).

  The shape inspection is performed for each of the plurality of products G through the series of processes described above. In the X-ray inspection apparatus 1, when it is determined that the feature amount is outside the range of the reference value, the product G corresponding to the X-ray transmission image is sorted by the sorting mechanism.

(4) Features and Functions / Effects According to the X-ray inspection apparatus 1, the X-ray transmission image 40 of the product G is generated by the image generation unit 21. Furthermore, the inspection unit corresponding to the product G is corrected by the correction unit 28, and a correction reference is generated. This correction reference is generated based on the position information of the X-ray transmission images 41 and 42 of the product G in the width direction and the height information of the product G. Then, the inspection is performed by the inspection unit 26 using the correction reference obtained by the correction. As described above, since the correction reference considering the position information of the X-ray transmission images 41 and 42 of the product G in the width direction and the height information of the product G is used for comparison at the time of correction, the width of the conveyor 5 The influence of the position of the product G in the direction is reduced. By using the correction reference, the accuracy of comparison with the transmission image is increased. Therefore, regardless of the position of the product G in the width direction of the conveyor 5, the product G can be accurately inspected by the inspection unit 26.

  In addition, since the inspection standard includes the reference area of the product G, the inspection of the product G based on the area, for example, the inspection of cracks is more accurate.

  In addition, since the inspection standard includes the reference perimeter of the product G, the inspection of the product G based on the perimeter, for example, the inspection of cracks is more accurate.

  A plurality of products G are transported while being arranged in the width direction on the conveyor 5, but the plurality of products G arranged in the width direction of the conveyor 5 are accurately inspected regardless of their positions. It can be carried out. For example, the X-ray transmission image 42 of the product G placed near the end in the width direction of the conveyor 5 is larger than the X-ray transmission image 41 of the product G placed in the center in the width direction, and is deformed. It is possible to do. Even in that case, a correction reference is generated based on the height information of the product G and the position information of the X-ray transmission image 42 in the width direction, and an inspection using the correction reference is performed. Therefore, even for the product G placed near the end in the width direction, the influence of changes in the size and shape of the X-ray transmission image 42 is reduced, and an accurate comparison is performed.

  The angle with respect to the X-ray irradiator 7 increases as the positions of the X-ray transmission images 41, 42, etc. of the product G are outward in the width direction of the conveyor 5. The larger the angle with respect to the X-ray irradiator 7, the greater the deformation rate of the size and shape of the X-ray transmission images 41, 42, etc. In the X-ray inspection apparatus 1, the correction rate of the inspection standard is increased by the correction unit 28 as the deformation rate of the size or shape of the X-ray transmission images 41, 42 is increased. The influence of changes in size and shape is appropriately reduced, and more accurate inspection is performed.

  X-rays are irradiated to the fan-shaped irradiation range X by the X-ray irradiator 7 and the X-ray line sensor 9 that are point light sources, but the product G is accurately detected regardless of the position of the product G in the width direction of the conveyor 5. Can be inspected.

(5) Modification <Modification 1>
In the above-described embodiment, the case where the feature amount (specifically, the area or the peripheral length) of the X-ray transmission images 41 and 42 is compared with the correction reference has been described. May be compared with a correction criterion. In this case, the reference value storage unit 32 stores a reference image of the product G as an inspection reference. That is, the inspection standard includes a standard image of the product G. Then, the correcting unit 28 corrects the reference image by multiplying the reference image by the correction rate calculated by the same method as described above, and generates a correction reference. More specifically, the correction unit 28 enlarges the reference image by increasing the number of pixels at each location included in the reference image. The inspection unit 26 may perform pattern matching when the X-ray transmission images 41 and 42 are compared with the correction reference. In this case, the binarization process in the feature amount calculation unit 22 may be omitted.

  Even with such an X-ray inspection apparatus, it is possible to inspect for cracks in the product G by comparing the size and shape of the X-ray transmission image. It is also possible to inspect the presence or absence of the contents of the product G by comparing the shades of the pixels included in the X-ray transmission image.

<Modification 2>
In the above-described embodiment, the correction unit 28 corrects the inspection standard. However, the correction unit 28 detects positional information such as the X-ray transmission images 41 and 42 of the product G in the width direction of the conveyor 5 and the product G. The X-ray transmission image may be corrected based on the height information. The correction unit 28 corrects the X-ray transmission image by multiplying the X-ray transmission image by a correction factor calculated by a method reverse to the above, and generates a correction image. More specifically, the correction unit 28 reduces the X-ray transmission image by reducing the number of pixels at each location included in the X-ray transmission image. In other words, the correction unit 28 does not delete a part of the pixels of the X-ray transmission image and uses all the pixels of the X-ray transmission image for correction. In this case, the correction factor calculated by the correction factor calculator 24 is 1 or less. The correction rate calculation unit 24 decreases the correction rate (that is, increases the degree of correction) as the position of each X-ray transmission image indicated by the position information is outward in the width direction. The correction rate calculation unit 24 decreases the correction rate (that is, increases the degree of correction) as the height of each product G indicated in the height information is higher. The inspection unit 26 inspects the article by comparing the corrected image or the feature amount thereof with the inspection standard.

  Even with such an X-ray inspection apparatus, the corrected image, which is a corrected transmission image, is used for comparison at the time of correction regardless of the position of the product G in the width direction of the conveyor 5. The comparison accuracy is improved.

  More specifically, when the inspection standard includes the reference area of the product G, the inspection unit 26 uses the area of the corrected image as the feature amount, and inspects the product G by comparing the area of the corrected image with the reference area. In this case, since the area of the corrected image is compared with the reference area, the inspection of the product G based on the area, for example, the inspection of cracks and cracks becomes more accurate.

  When the inspection standard includes the reference peripheral length of the product G, the inspection unit 26 inspects the product G by using the peripheral length of the corrected image as a feature amount and comparing the peripheral length of the corrected image with the reference peripheral length. . In this case, since the peripheral length of the corrected image is compared with the reference peripheral length, the inspection of the article based on the peripheral length, for example, the inspection of cracks is more accurate.

  Further, the present invention is not limited to the case where the feature amount of the X-ray transmission images 41 and 42 is calculated. For example, the X-ray transmission images 41 and 42 themselves may be used for comparison in the inspection unit 26. In this case, the inspection reference includes a reference image of the product G, and the inspection unit 26 inspects the article by comparing the corrected image with the reference image. According to this, since the corrected image is compared with the reference image, the inspection of the product G based on the image becomes more accurate. For example, the product G can be inspected for cracks by comparing the sizes and shapes of the images. It is also possible to inspect the presence or absence of the contents of the product G by comparing the shades of pixels included in the image.

<Other variations>
In the above-described embodiment, the position in the width direction of the X-ray transmission images 41 and 42 and the like is detected. The detection of the position of the product G may be omitted by placing the product G at a known position and setting or inputting the position of the product G in advance. The height information of the product G is not limited to being stored in the height storage unit 31, and the height of the product G may be detected. The width direction of the conveyor 5 is not limited to being orthogonal to the transport direction D. It may be a direction that intersects the transport direction D at an angle other than 90 degrees.

  In the above embodiment, the position detection unit 23 has described the case of detecting the distance (position) of the pixel having the largest distance in the width direction from the center pixel among the pixels constituting each X-ray transmission image. However, the position detector 23 may generate position information by calculating an average position of all the pixels constituting the X-ray transmission image.

  Although the said embodiment demonstrated the case where the X-ray inspection apparatus 1 was provided with the X-ray irradiator 7 and the X-ray line sensor 9 which are point light sources, the light irradiator which is a line light source, and a point-like photodetector The X-ray inspection apparatus provided with these may be sufficient. Also in this case, the light irradiated to the fan-shaped irradiation range X spreading in the width direction of the conveyor 5 is detected by the photodetector. By performing the same correction and comparison as the above-described embodiments, the product G can be accurately inspected by the inspection unit 26 regardless of the position of the product G in the width direction of the conveyor 5.

  In the above embodiment, an example has been described in which an article is irradiated with X-rays and a transmission image is generated based on the X-rays transmitted through the article. However, the present invention is not limited to this. For example, the present invention can be applied to a near-infrared inspection apparatus (inspection apparatus) that includes an image generation unit that irradiates an article with near infrared rays and generates a transmission image based on the near infrared rays transmitted through the article. .

  Various embodiments and modifications described above may be combined in various ways without departing from the spirit of the present invention.

  DESCRIPTION OF SYMBOLS 1 ... X-ray inspection apparatus (inspection apparatus), 5 ... Conveyor, 7 ... X-ray irradiator (light irradiation part), 9 ... X-ray line sensor (line sensor), 21 ... Image generation part, 26 ... Inspection part, 28 ... corrector, 41, 42 ... X-ray transmission image (transmission image of article), D ... transport direction, G ... commodity (article).

Claims (9)

A light irradiation unit configured to irradiate light on an article placed on a conveyor and conveyed in a conveyance direction; an image generation unit configured to generate a transmission image of the article based on light transmitted through the article; and transmission of the article An inspection unit that inspects the article using an image and an inspection standard,
By correcting the transmission image or the inspection standard based on the position information of the article or the transmission image of the article in the width direction intersecting the transport direction and the height information of the article, the corrected image or the correction reference An inspection apparatus comprising a correction unit that generates   The inspection apparatus according to claim 1, wherein the correction unit generates the correction reference by correcting the inspection reference based on the position information and the height information.   The inspection apparatus according to claim 1, wherein the correction unit generates the corrected image by correcting the transmission image based on the position information and the height information.   The inspection apparatus according to claim 1, wherein the inspection standard includes a reference area of the article.   The inspection apparatus according to claim 1, wherein the inspection standard includes a reference perimeter of the article.   The inspection apparatus according to claim 1, wherein the inspection reference includes a reference image of the article.   The inspection apparatus according to any one of claims 1 to 6, wherein a plurality of the articles are conveyed in a row in the width direction on the conveyor.   The correction unit increases the degree of correction of the transmission image or the inspection standard as the position of the article or the transmission image of the article indicated in the position information is outward in the width direction. The inspection apparatus as described in any one of -7. The light irradiation unit is a point light source,
The inspection apparatus according to claim 1, wherein the image generation unit includes a line sensor arranged in the width direction.

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