JP2013152127A - Density calculation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a density calculation apparatus in which density data can be obtained efficiently from a number of articles.SOLUTION: A density calculation apparatus comprises an X-ray irradiation section, an X-ray detection section, an image generation section, a weight estimation section, a shape information storage region, a planar shape identification section, a volume estimation section and a density calculation section. The image generation section generates an X-ray image in accordance with an intensity of transmitted X-rays detected by the X-ray detection section. The weight estimation section estimates a weight of an article. The shape information storage region stores therein shape information about a plurality of stereoscopic shapes and planar shapes corresponding to the stereoscopic shapes. The planar shape identification section identifies a target planar shape that is a planar shape of an article corresponding to the X-ray image on the basis of the shape information stored in the shape information storage region. The volume estimation section estimates a volume of the article on the basis of a stereoscopic shape corresponding to the target planar shape. Te density calculation section calculates a density of the article on the basis of the weight of the article detected by the weight estimation section and the volume of the article estimated by the volume estimation section.

Description

  The present invention relates to a density calculation apparatus.

  Conventionally, in the food industry and the like, various techniques using a transmitted X-ray dose obtained by transmitting X-rays through an article have been proposed. For example, based on the transmitted X-ray dose, detection of foreign matters mixed in a packaged article (product) or estimation of the weight of the article as shown in Patent Document 1 (Japanese Patent Application Laid-Open No. 2002-296022) is performed. Yes.

  By the way, in recent years, there has been a demand for density data of articles. Conventionally, in order to collect density data of an article, the article is randomly extracted from a number of articles flowing in the food production line, and the weight and volume of the removed article are measured to obtain density data.

  However, in the conventional method, some articles are extracted from a large number of articles flowing in the food production line, and the extracted articles are used as inspection target articles. As a result, the number of data on which density data is based has been limited. Increasing the number of articles to be inspected can provide more accurate density data for articles handled in the food production line, but it takes time to perform sampling and data collection.

  An object of the present invention is to provide a density calculation device that makes it possible to efficiently obtain density data from a large number of articles.

  A density calculation apparatus according to the present invention includes an X-ray irradiation unit, an X-ray detection unit, an image generation unit, a weight estimation unit, a shape information storage area, a planar shape identification unit, a volume estimation unit, and a density calculation. A section. The X-ray irradiation unit irradiates the article with X-rays. The X-ray detection unit detects X-rays that have passed through the article. The image generation unit generates an X-ray image according to the intensity of the transmitted X-ray detected by the X-ray detection unit. The weight estimation unit estimates the weight of the article. The shape information storage area stores shape information regarding a plurality of three-dimensional shapes and a planar shape corresponding to the plurality of three-dimensional shapes. The planar shape identifying unit identifies a target planar shape, which is a planar shape of the article corresponding to the X-ray image, based on the shape information stored in the shape information storage area. The volume estimation unit estimates the volume of the article based on the three-dimensional shape corresponding to the target planar shape. The density calculation unit calculates the density of the article based on the weight of the article detected by the weight estimation unit and the volume of the article estimated by the volume estimation unit.

  Thereby, density data can be easily obtained from a large number of articles.

  Furthermore, it is preferable that a planar shape identification part specifies the major axis and minor axis of an article based on an X-ray image. Moreover, it is preferable that a volume estimation part estimates the volume of an article | item using the algorithm for calculating | requiring the volume of several solid shapes, and the long diameter and short diameter which were specified by the planar shape identification part.

  Thereby, the density data of articles of various sizes can be collected.

  The plurality of three-dimensional shapes preferably include at least one of an ellipsoid, a cone, and a cylinder.

  Thereby, it can employ | adopt for collection of the density data regarding various articles | goods.

  Furthermore, it is preferable that the density calculation apparatus according to the present invention further includes an input unit and an association information storage area. The input unit accepts selection regarding the type of the target article. The association information storage area stores association information between the type of the target article and the planar shape. Moreover, it is preferable that a plane shape identification part selects the object plane shape which is a plane shape linked | related with the kind of object article according to the selection received in the input part. Moreover, it is preferable that a volume estimation part estimates the volume of an article | item based on the solid shape corresponding to the object plane shape selected by the plane shape identification part.

  Thereby, the density data of articles can be easily collected.

  Furthermore, it is preferable that the planar shape identifying unit automatically selects a target planar shape from a plurality of planar shapes stored in the shape storage area based on the major axis and the minor axis. Moreover, it is preferable that a volume estimation part estimates the volume of an article | item based on the solid shape corresponding to the object plane shape automatically selected by the plane shape identification part.

  Thereby, the density data of articles can be easily collected.

  Moreover, it is preferable that a weight estimation part estimates the weight of articles | goods based on an X-ray image.

  Accordingly, the density of the article can be calculated without using another device that measures the weight of the article.

  According to the density calculation apparatus according to the present invention, density data can be easily obtained from a large number of articles.

1 is an external perspective view of an X-ray inspection apparatus according to an embodiment of the present invention. 1 is a schematic view of an inspection line (X-ray inspection system) including an X-ray inspection apparatus. It is a simple block diagram inside the shield box of an X-ray inspection apparatus. It is a graph which shows the example of the transmitted X-ray dose detected by an X-ray detection element. It is a control block diagram. It is an example of a weight conversion table. It is an example of shape basic information. It is a figure which shows the flow of the process which concerns on density calculation. It is a figure which shows the determination process of a potato planar shape. It is a figure which shows the determination process of a potato planar shape. It is a figure which shows the determination process of a potato planar shape. It is a figure which shows the determination process of a potato planar shape. It is a figure which shows the determination process of the planar shape of a carrot. It is a figure which shows the determination process of the planar shape of a carrot. It is a figure which shows the determination process of the planar shape of a carrot. It is a figure which shows the determination process of the planar shape of a carrot.

  Hereinafter, an X-ray inspection apparatus according to an embodiment of the present invention will be described with reference to the drawings.

(1) Schematic description of X-ray inspection apparatus FIG. 1 is a perspective view showing an appearance of an X-ray inspection apparatus (density calculation apparatus) 10 according to an embodiment of the present invention. FIG. 2 shows an example of an inspection line (X-ray inspection system) 100 in which the X-ray inspection apparatus 10 is incorporated. In the inspection line 100, an inspection of an article G such as food is performed. In addition to the X-ray inspection apparatus 10, the inspection line 100 includes an upstream conveyor unit 60 and a distribution mechanism 70. The upstream conveyor unit 60 is provided upstream of the X-ray inspection apparatus 10.

  The X-ray inspection apparatus 10 determines the quality of the article G by irradiating the article G continuously conveyed by the upstream conveyor unit 60 with X-rays. Specifically, the X-ray inspection apparatus 10 calculates the density of the article G based on the X-ray dose that has passed through the article G, and inspects whether or not the density is within a predetermined range. The X-ray inspection apparatus 10 determines that the article G is a non-defective product when the density is within a predetermined range, and determines that the product is a defective product when the density is outside the predetermined range. The inspection result in the X-ray inspection apparatus 10 is sent to a sorting mechanism 70 provided downstream of the X-ray inspection apparatus 10. The distribution mechanism 70 is connected to the line conveyor unit 80 and the defective product collection line 90. The distribution mechanism 70 distributes the articles G determined as non-defective products in the X-ray inspection apparatus 10 to the line conveyor unit 80 and distributes the articles G determined as defective products to the defective product collection line 90.

(2) Detailed description of X-ray inspection apparatus As shown in FIG. 1, FIG. 3, or FIG. 5, the X-ray inspection apparatus 10 mainly includes a shield box 11, a conveyor unit (conveying unit) 12, and X-ray irradiation. A device (X-ray irradiation unit) 13, an X-ray line sensor (X-ray detection unit) 14, a monitor (corresponding to an input unit) 30 with a touch panel function, and a control device 20.

(2-1) Shield Box The shield box 11 is a box that houses a conveyor unit 12, an X-ray irradiator 13, an X-ray line sensor 14, a control device 20, and the like which will be described later. In addition to the monitor 30, a key insertion slot, a power switch, and the like are disposed on the upper front portion of the shield box 11. Openings 11 a are formed on both side surfaces of the shield box 11. The opening 11a is used to carry the article G into and out of the shield box 11. The opening 11a is blocked by a shielding noren (not shown). The shield noren prevents X-rays inside the shield box 11 from leaking to the outside. The shielding nolen is molded from rubber containing lead. The shielding nolen is pushed away by the article G when the article G passes through the opening 11a.

(2-2) Conveyor unit The conveyor unit 12 conveys the article G within the shield box 11. As shown in FIG. 1, the conveyor unit 12 is disposed so as to penetrate through the openings 11 a formed on both side surfaces of the shield box 11. The conveyor unit 12 mainly includes an endless belt, a driving roller, and a conveyor motor 12a (see FIG. 5). The driving roller is driven by the conveyor motor 12a. By driving the drive roller, the belt is rotated and the article G on the belt is conveyed downstream. The conveyance speed of the articles G by the conveyor unit 12 varies according to the set speed input by the operator. The control device 20 performs inverter control of the conveyor motor 12a based on the set speed, and finely controls the conveyance speed of the article G. The conveyor motor 12a is equipped with an encoder 12b (see FIG. 5) that detects the conveyance speed of the conveyor unit 12 and sends it to the control device 20.

(2-3) X-ray irradiator The X-ray irradiator 13 is disposed above the conveyor unit 12 as shown in FIG. The X-ray irradiator 13 irradiates the fan-shaped irradiation range X with X-rays toward the X-ray line sensor 14. The irradiation range X extends perpendicular to the transport surface of the conveyor unit 12. Further, the irradiation range X extends in a fan shape in a direction that intersects the transport direction of the conveyor unit 12. That is, the X-rays emitted from the X-ray irradiator 13 spread in the belt width direction.

(2-4) X-ray line sensor The X-ray line sensor 14 is arrange | positioned under the conveyor unit 12, as shown in FIG. The X-ray line sensor 14 is mainly composed of a large number of X-ray detection elements 14a. The X-ray detection elements 14a are horizontally arranged in a straight line in a direction orthogonal to the conveyance direction by the conveyor unit 12. Each X-ray detection element 14a detects an X-ray dose (transmitted X-ray dose) that has passed through the article G or the conveyor unit 12, and outputs an X-ray transmission signal based on the transmitted X-ray dose. In other words, the X-ray transmission signal outputs an X-ray transmission signal corresponding to the intensity of the transmitted X-ray. The intensity of the transmitted X-ray depends on the magnitude of the transmitted X-ray dose. The brightness (shading value) of the X-ray image is determined by the X-ray transmission signal (see FIG. 4). FIG. 4 is a graph showing an example of transmitted X-ray dose (detection amount) detected by the X-ray detection element 14a of the X-ray line sensor 14. The horizontal axis of the graph corresponds to the position of each X-ray detection element 14a. The horizontal axis of the graph corresponds to the distance in the direction orthogonal to the conveying direction of the conveyor 12. The vertical axis of the graph indicates the amount of X-ray transmission (detection amount) detected by the X-ray detection element 14a. That is, a portion with a large detection amount is displayed as a bright (light) X-ray image, and a portion with a small detection amount is displayed as a dark (dark) X-ray image. That is, the lightness (darkness) of the X-ray image corresponds to the detected amount of X-rays. The brightness (darkness) of the X-ray image corresponds to the weight of the article G.

  Furthermore, the X-ray line sensor 14 also functions as a sensor for detecting the timing when the article G as a specimen passes through the fan-shaped X-ray irradiation range X (see FIG. 3). That is, the X-ray line sensor 14 indicates an X-ray indicating a voltage equal to or lower than a predetermined threshold when the article G conveyed on the belt of the conveyor unit 12 comes to an upper position (irradiation range X) of the X-ray line sensor 14. A transmission signal (first signal) is output. On the other hand, when the article G passes the irradiation range X, the X-ray line sensor 14 outputs an X-ray transmission signal (second signal) indicating a voltage exceeding a predetermined threshold. The presence or absence of the product G in the irradiation range X is detected by inputting the first signal and the second signal to the control device 20 described later.

(2-5) Monitor The monitor 30 is a liquid crystal display. The monitor 30 displays a screen that prompts the operator to input inspection parameters and the like necessary for the inspection. The monitor 30 also has a touch panel function. The monitor 30 accepts input from the operator such as inspection parameters (types of articles to be inspected and appropriate density ranges). The inspection parameters received by the monitor 30 are stored in the storage unit 21 described later.

(2-6) Control Device The control device 20 mainly includes a storage unit 21 and a control unit 22 as shown in FIG. The storage unit 21 includes a ROM, a RAM, a hard disk, and the like. The control unit 22 is configured by a CPU. The control device 20 also includes a display control circuit, a key input circuit, a communication port, and the like (not shown). The display control circuit is a circuit that controls data display on the monitor 30. The key input circuit is a circuit that captures key input data input by an operator via the touch panel of the monitor 30. The communication port enables connection with an external device such as a printer or a network such as a LAN.

  The control device 20 is also connected to the above-described conveyor motor 12a, encoder 12b, X-ray irradiator 13, X-ray line sensor 14, and the like. The control device 20 acquires data relating to the rotation speed of the conveyor motor 12a from the encoder 12b, and grasps the moving distance of the article G based on the data. Further, as described above, the control device 20 receives the signal output from the X-ray line sensor 14 to detect the timing when the article G on the belt of the conveyor unit 12 has come to the irradiation range X.

(2-6-1) Storage Unit The storage unit 21 stores various programs and inspection parameters to be executed by the control unit 22. The inspection parameters are input by the operator using the touch panel function of the monitor 30 as described above. In addition, the storage unit 21 stores a weight conversion table (see FIG. 6) and data relating to a histogram. The weight conversion table is a table for weight estimation used by a weight estimation unit 22d described later. The data relating to the histogram is data created by a histogram creating unit 22b described later.

  Furthermore, the storage unit 21 mainly includes an X-ray image storage area 21a, a basic shape information storage area 21b, an identification shape storage area 21c, an estimated information storage area 21d, and a density data storage area 21e.

(A) X-ray image storage area The X-ray image storage area 21a stores data (image data) related to an image generated by an image generation unit 22a described later. The image includes the article G and the background of the article G.

(B) Shape Basic Information Storage Area Basic information regarding the shape of the article G (shape basic information) is stored in the shape basic information storage area 21b. The basic shape information includes first basic information and second basic information.

  The first basic information is basic information for determining the planar shape of the article G to be inspected. Planar shapes include circles, ellipses, triangles, rectangles, and squares. Specifically, the first basic information is a function or algorithm for obtaining planar shapes of various sizes. More specifically, the first basic information is a function or algorithm for obtaining a planar shape having a size approximate to the planar shape (target planar shape) of the article G to be inspected.

  The second basic information is basic information regarding the three-dimensional shape. Solid shapes include spheres, ellipsoids, cones, cylinders, cuboids, and cubes. Specifically, the second basic information is a function or algorithm for obtaining the volume of the three-dimensional shape.

  In the shape basic information storage area 21b, a plurality of types of planar shapes related to the first basic information and a plurality of types of three-dimensional shapes related to the second basic information are stored in association with each other. Specifically, as shown in FIG. 7, the shape basic information storage area 21b stores a plurality of combinations of one plane shape type and one three-dimensional shape type associated with the plane shape type. Has been.

  Furthermore, as shown in FIG. 7, in the basic shape information storage area 21b, the planar shape and the three-dimensional shape are stored in association with the type of the inspection target article G. For example, “apple” is associated with a planar “circle” and a three-dimensional “sphere”. Also, “potato” and “kiwi” are associated with a planar “ellipse” and a three-dimensional “ellipsoid”.

  When the inspection object G input to the monitor 30 is “apple”, the first combination is referred to by the planar shape identification unit 22c and the volume estimation unit 22e described later. That is, the planar shape identification unit 22c refers to the first basic information (a function or algorithm for obtaining a circle of a predetermined size) associated with “apple”. Further, the volume estimation unit 22e refers to the second basic information (function or algorithm for calculating the volume of the sphere) associated with the “sphere”.

(C) Identification shape storage area The identification shape storage area 21c stores an identification result by a planar shape identification unit 22c described later. That is, information regarding the planar shape of each article G is stored in the identification shape storage area 21c. Specifically, in the identification shape storage area 21c, the type of plane shape (target plane shape) corresponding to the inspection target article G selected by the plane shape identification unit 22c and the plane shape determined by the plane shape identification unit 22c. Information on the size (major axis L1 and minor axis L2) is stored.

(D) Estimated information storage area In the estimated information storage area 21d, information (estimated weight information) on the weight of the article G estimated by the weight estimation unit 22d described later (estimated weight information) and the article G estimated by the volume estimation unit 22e described later are stored. An estimated volume (estimated volume information) is stored.

(E) Density data storage area The density data storage area 21e stores density data of the article G calculated by a density calculation unit 22f described later.

(2-6-2) Control Unit The control unit 22 executes various programs stored in the storage unit 21, thereby causing the image generation unit 22a, the histogram creation unit 22b, the planar shape identification unit 22c, the weight estimation unit 22d, It functions as a volume estimation unit 22e, a density calculation unit 22f, and a pass / fail determination unit 22g.

(A) Image Generation Unit The image generation unit 22a generates an X-ray image based on the transmitted X-ray dose detected by the X-ray line sensor 14. Specifically, the image generation unit 22a acquires X-ray transmission signals output from the X-ray detection elements 14a of the X-ray line sensor 14 at fine time intervals, and an X-ray image based on the acquired X-ray transmission signals. Is generated. That is, the image generation unit 22a generates the article G based on the X-ray transmission signal output from each X-ray detection element 14a when the article G passes through the fan-shaped X-ray irradiation range X (see FIG. 3). An X-ray image including the image is generated. The presence / absence of the article G in the irradiation range X is determined by a signal output from the X-ray line sensor 14. The image generation unit 22a generates an X-ray image of the article G by linking time-series data in fine time intervals regarding the X-ray intensity (brightness) obtained from each X-ray detection element 14a. To do. The X-ray image generated by the image generation unit 22a is stored in the X-ray image storage area 21a.

(B) Histogram Creation Unit The histogram creation unit 22b creates information related to the gray value of the X-ray image based on the X-ray image generated by the image generation unit 22a. Specifically, the histogram creation unit 22b creates a histogram indicating the number of pixels for each gray value based on the X-ray image. In other words, the histogram creation unit 22b classifies all pixels constituting the X-ray image for each gray value (tone) having a predetermined width, and counts the number of pixels having each gray value. Thereby, a histogram indicating the number of pixels for each gray value is created for the X-ray image. Data relating to the histogram of the X-ray image created by the histogram creation unit 22 b is stored in the storage unit 21.

(C) Plane shape identification unit The plane shape identification unit 22c identifies the planar shape of the article G based on the type of the article G received by the monitor 30 and the X-ray image stored in the X-ray image storage area 21a. .

  Specifically, the planar shape identifying unit 22c binarizes the X-ray image and specifies the image of the article G included in the X-ray image. In addition, the planar shape identification unit 22c identifies pixels (contour pixels) that configure the outline of the article G among all the pixels that configure the image of the article G. Further, the planar shape identifying unit 22c determines a planar shape having a size that is most approximate to the planar shape constituted by the contour pixels, based on the type of the article G and the arrangement of the contour pixels.

  Specifically, the planar shape identification unit 22c identifies pixels (contours) constituting the contour of the article G in the X-ray image by specifying a portion having extremely different gray values among all the pixels constituting the X-ray image. Pixel). The planar shape identifying unit 22c selects a planar shape associated with the inspection target article G from a plurality of types of planar shapes stored in the basic shape information storage area 21b. The planar shape identifying unit 22c determines a planar shape (approximate shape) that is most approximate to the planar shape constituted by the contour pixels of the article G based on the first basic information related to the selected planar shape and the coordinates of each contour pixel. judge. In other words, the planar shape identifying unit 22c determines the minimum planar shape (approximate shape) that can include all of the portion surrounded by the contour pixels of the article G based on the first basic information.

  Further, the planar shape identifying unit 22c identifies the dimensions of the article G (for example, the major axis dimension L1 and the minor axis dimension L2) based on the approximate shape of the article G. Specifically, the planar shape identifying unit 22c identifies the major axis L1 and the minor axis L2 of the approximate shape of the article G.

  Note that the type of the planar shape selected by the planar shape identifying unit 22c and the size of the article G identified by the planar shape identifying unit 22c are stored in the above-described identified shape storage area 21c.

(D) Weight Estimation Unit The weight estimation unit 22d estimates the weight of the article G based on the data relating to the histogram stored in the storage unit 21 and the weight conversion table (see FIG. 6). Specifically, the weight estimation unit 22d refers to the weight conversion table and calculates a weight value (m) corresponding to the gray value of all the pixels constituting the image of the article G. Furthermore, the weight estimation unit 22d estimates the weight value (total weight) of the article G by adding the weight values (m) corresponding to all the pixels. Information (estimated weight information) related to the estimated weight of the article G obtained by the weight estimating unit 22d is stored in the estimated information storage area 21d.

(E) Volume Estimating Unit The volume estimating unit 22e estimates the volume of the article G based on the planar shape of the article G selected by the planar shape identifying unit 22c and the second basic information. The 2nd basic information used here is the 2nd basic information about the solid shape memorized in relation to the plane shape of article G to be examined. That is, the volume estimation unit 22e estimates the volume of the article G using an algorithm for obtaining a volume of a three-dimensional shape corresponding to the selected planar shape. Information (estimated volume information) on the estimated volume of the article G obtained by the volume estimation unit 22e is also stored in the estimated information storage area 21d.

(F) Density Calculation Unit The density calculation unit 22f calculates the density of the article G based on the estimated weight information and estimated volume information stored in the estimated information storage area 21d. Specifically, the density calculation unit 22f obtains the density (specific gravity) ρ of the article G by dividing the estimated weight w of the article G by the estimated volume V of the article G (ρ = w / V).

  In addition, the density calculation unit 22f corrects the density ρ of the obtained article G. Specifically, the density calculator 22f multiplies the density ρ of the article G by an arbitrary coefficient c to obtain the corrected density ρc. Information (density data) related to the density of the article G calculated by the density calculation unit 22f is stored in the density data storage area 21e.

(G) Pass / Fail Judgment Unit The pass / fail judgment unit 22g performs a pass / fail judgment on the article G. First, the pass / fail judgment unit 22g judges pass / fail items for the article G based on the density data. Specifically, the pass / fail determination unit 22g determines whether the density data stored in the density data storage area 21e is included in a predetermined density range. The predetermined density range is a range of values serving as a reference for determining the quality of the article G, and is one of parameters input by the operator and stored in the storage unit 21. The storage unit 21 stores information on a density range (appropriate density range) according to the type of the article G and the weight of the article G. That is, the pass / fail determination unit 22g determines whether the density (calculated density) of the article G calculated by the density calculation unit 22f is within a range of appropriate density according to the type and weight of the article G. When the calculated density of G is included in the range of the appropriate density, the article G is determined as a non-defective product. On the other hand, when the calculated density of the article G is out of the appropriate density range, the article G is determined as a defective product.

  When determining whether the article G is good / defective, the quality determination unit 22g outputs a signal (determination result) indicating that the article G is either a good / defective product. The signal output by the pass / fail determination unit 22g is sent to the distribution mechanism 70. The distribution mechanism 70 distributes the articles G to the line conveyor unit 80 or the defective product collection line 90 based on the determination result by the pass / fail determination unit 22g.

(3) Process Flow (3-1) Overall Flow First, the process flow by the X-ray inspection apparatus 10 will be described. When the article G is inserted into the X-ray inspection apparatus 10, an X-ray image of the article G is generated by the image generation unit 22a. When the X-ray image is generated, based on the X-ray image and the first basic information related to the planar shape stored in association with the article G, the planar shape identifying unit 22c is most suitable for the planar shape of the article G. A plane shape (approximate shape) having an approximate size and a dimension of the approximate shape are determined. The volume estimation unit 22e estimates the volume of the article G based on the determined planar shape dimension and the second basic information related to the solid shape stored in association with the determined planar shape.

  On the other hand, the histogram creation unit 22b creates a histogram indicating the number of pixels for each gray value based on the gray value of each pixel constituting the X-ray image. The weight estimation unit 22d estimates the weight of the article G based on the histogram.

  Thereafter, the density calculation unit 22f obtains the density (specific gravity) of the article G based on the estimated volume of the article G (estimated volume) and the estimated weight of the article G (estimated weight). Specifically, the density calculation unit 22f calculates the density (specific gravity) ρ of the article G by dividing the estimated weight w of the article G by the estimated volume V (ρ = w / V). The density calculation unit 22f further calculates a correction density ρc by multiplying the obtained density ρ by an arbitrary coefficient c.

  Thereafter, the quality determination unit 22g determines the quality of the product G. The product G determined to be good is sent to the line conveyor unit 80, and the product G determined to be defective is sent to the defective product collection line 90. It is done.

(3-2) Process Flow for Density Calculation Next, a process flow for calculating the density of the article G will be described in detail with reference to FIGS. 8 to 10D. FIG. 8 shows the flow of processing related to the density calculation of the article G. 9A to 10D are diagrams for illustrating a specific example of processing related to the shape determination of the article G. FIG.

  In step S1, the X-ray image stored in the X-ray image storage area 21a is binarized (see FIGS. 9A and 10A).

  Thereafter, in step S2, the outline of the article G is determined based on the binarized X-ray image. Specifically, among all the pixels constituting the X-ray image, a portion where the gray values of adjacent pixels are extremely different is specified (see FIGS. 9B and 10B).

  Next, in step S3, a planar shape having a size closest to the planar shape constituted by the contour (contour pixel) of the article G is determined (see FIGS. 9C and 10C). Specifically, the planar shape identifying unit 22c selects the type of planar shape corresponding to the article G. Furthermore, the planar shape identifying unit 22c has a planar shape (size closest to the planar shape of the article G) based on the first basic information related to the planar shape and the arrangement (coordinates) of the contour pixels of the article G ( Approximate shape) is determined. More specifically, the planar shape identifying unit 22c determines the minimum planar shape that can include all of the portion surrounded by the contour pixels of the article G based on the first basic information.

  Thereafter, in step S4, the dimensions of the approximate shape are specified. Specifically, the major axis dimension L1 and the minor axis dimension L2 of the approximate shape are specified (see FIGS. 9D and 10D).

  In step S5, the volume of the article G is estimated based on the approximate shape dimensions and the second basic information associated with the article G. Specifically, the volume of the article G is estimated using the major axis L1 and the minor axis L2 of the approximate shape and the second basic information regarding the three-dimensional shape (see FIG. 7) associated with the planar shape of the article G. The

  In step S6, the density of the article G is calculated. Specifically, the density ρ of the article G is calculated by dividing the estimated weight w of the article G by the estimated volume V of the article G.

  Thereafter, in step S7, the obtained value (density ρ) is multiplied by an arbitrary coefficient c to calculate a correction value (correction density) ρc.

(3-3) Specific example (3-3-1) When the inspection target article is “potato” The density calculation method when the inspection target article G is a potato is specifically described with reference to FIGS. 9A to 9D. To do. First, as shown in FIG. 9A, the X-ray image is binarized. Thereafter, as shown in FIG. 9B, the outline of the potato included in the X-ray image is determined. Thereafter, as shown in FIG. 9C, a planar shape that approximates the size of the potato to be inspected is determined. Here, in the shape basic information storage area 21b, the planar shape stored in association with “potato” is “ellipse”. Therefore, based on the first basic information for obtaining “ellipses” of various sizes and the outline of the potato, an ellipse having a size that most closely approximates the planar shape of the potato to be inspected is determined. Specifically, the planar shape identification unit 22c determines the minimum planar shape (approximate shape) that can include all of the portions surrounded by the potato outline pixels based on the first basic information about the ellipse. Thereafter, as shown in FIG. 9D, the major axis dimension L1 and the minor axis dimension L2 of the approximate shape are specified.

Furthermore, the potato volume V is estimated based on the second basic information and the dimensions of the approximate shape. Here, the three-dimensional shape stored in association with “ellipse” in the shape basic information storage area 21 b is “ellipsoid”. Therefore, the volume V of “potato” is estimated based on the second basic information on the “ellipsoid” and the approximate shape dimensions L1 and L2 (V = 4/3 × π × L1 × L2 ² ).

  Thereafter, the density ρ is calculated by dividing the potato weight (estimated weight) w, which is estimated separately, by the estimated volume V. Further, the obtained value (density ρ) is multiplied by an arbitrary coefficient c to calculate a correction value (correction density) ρc.

(3-3-2) When the inspection target article is a carrot The density calculation method when the inspection target article G is a carrot is specifically described with reference to FIGS. 10A to 10D. First, as shown in FIG. 10A, the X-ray image is binarized. Thereafter, as shown in FIG. 10B, the outline of the carrot included in the X-ray image is determined. Thereafter, as shown in FIG. 10C, a planar shape that approximates the size of the carrot to be examined is determined. Here, in the basic shape information storage area 21b, the planar shape stored in association with “carrot” is “rectangular”. Therefore, based on the first basic information for obtaining “rectangles” of various sizes and the outline of the carrot, a rectangle having a size closest to the carrot to be inspected is determined. Specifically, the planar shape identifying unit 22c determines the minimum planar shape (approximate shape) that can include all of the portions surrounded by the carrot outline pixels based on the first basic information regarding the rectangle. Thereafter, as shown in FIG. 10D, the major axis dimension L1 and the minor axis dimension L2 of the approximate shape are specified.

Furthermore, the carrot volume V is estimated on the basis of the second basic information and the dimensions of the approximate shape. Here, the three-dimensional shape stored in association with the “rectangle” in the shape basic information storage area 21 b is “cone”. Accordingly, the volume V of “carrot” is estimated based on the second basic information on “rectangle” and the dimensions L1 and L2 of the approximate shapes (V = 1/3 × π × L1 × (L2 / 2)). ² ).

  Thereafter, the density ρ is calculated by dividing the carrot weight (estimated weight) w separately estimated by the estimated volume V. Further, the obtained value (density ρ) is multiplied by an arbitrary coefficient c to calculate a correction value (correction density) ρc.

(4) Features (4-1)
The X-ray inspection apparatus 10 according to the embodiment collects density data of the article G. Conventionally, when collecting the density data of the article G, some articles are extracted from a large number of articles flowing in the food production line, and the extracted articles are used as inspection target articles. Therefore, the number of data on which density data is based is limited. Further, when the number of articles to be inspected is increased, more accurate density data on articles handled in the food production line can be obtained, but sampling work and data collection become complicated.

  However, in the X-ray inspection apparatus 10 according to the above embodiment, density data can be automatically collected for all articles G that have been input. Thereby, accurate density data can be obtained efficiently.

(4-2)
In the above embodiment, the article G is based on the major axis L1 and minor axis L2 of the article G specified by the planar shape identifying unit 22c and the function or algorithm (second basic information) for obtaining the volume of the three-dimensional shape. Is estimated. Thereby, density data of articles G of various sizes can be collected.

(4-3)
The basic shape information storage area 21b according to the above embodiment stores basic information (first basic information) regarding a plurality of types of planar shapes and information (second basic information) regarding a plurality of types of solid shapes. Thereby, the density data regarding various articles G can be collected.

(4-4)
Moreover, in the said embodiment, in the one X-ray inspection apparatus 10, the weight of the article | item G is estimated, Furthermore, the density of the article | item G is calculated | required using the estimated weight of the article | item G. Accordingly, the density of the article can be calculated without using another device that measures the weight of the article.

(5) Modification (5-1)
In the above embodiment, the pass / fail determination unit 22g determines pass / fail of the article G based on whether or not the calculated density of the article G is within the range of the appropriate density. Here, the control unit 22 may be configured to further function as a foreign matter inspection unit. The foreign substance inspection unit detects the foreign substance contained in the article G from the X-ray image that has been subjected to the binarization process. Specifically, when there is an area that appears darker than a preset threshold on the X-ray image, it is determined that foreign matter is mixed in the article G, and the article G is determined to be abnormal. The result of the foreign substance inspection by the foreign substance inspection unit is stored in the storage unit 21. The quality determination unit 22g determines the quality of the article G based on the density data of the article G and the result of the foreign substance inspection. Thereby, not only the density of the article G but also the foreign matter inspection of the article G can be performed at the same time.

(5-2)
In the above embodiment, the planar shape identifying unit 22c is configured by the contour pixels of the article G based on the information related to the inspection target article G input by the operator and the first basic information stored in the basic shape information storage area 21b. A planar shape (approximate shape) having a size that approximates the planar shape to be measured is determined. Here, the planar shape identifying unit 22c may determine a planar shape (approximate shape) of the type and size that is most approximate to the planar shape of the inspection target article G based on the coordinates of the contour pixel.

  Specifically, first basic information that is a function or algorithm for obtaining a plurality of types of planar shapes and a plurality of sizes of planar shapes is stored in the shape basic information storage area 21b. The planar shape identification unit 22c determines the major axis L1 and the minor axis L2 of the article G based on the coordinates of the contour pixel. Further, the planar shape identifying unit 22c is based on the major axis L1 and minor axis L2 of the article G and the first basic information, and the planar shape (approximate shape) of the type and size that is most approximate to the planar shape of the article G to be inspected. May be determined. That is, the planar shape identifying unit 22c may automatically configure the planar shape type of the inspection target article G and further configure the X-ray inspection apparatus 10 so as to determine the size of the planar shape. The volume estimation unit 22e estimates the volume of the article G based on the second basic information of the solid shape corresponding to the automatically selected planar shape. In this case, in the shape basic information storage area 21b, there is no need to associate the inspection target article G with the first basic information and the second basic information, and the first basic information and the second basic information are associated with each other. Just do it. Thereby, even when different types of articles G are put into the X-ray inspection apparatus, it is possible to appropriately collect density data for various types of articles G.

(5-3)
In the above embodiment, the X-ray dose irradiated by the X-ray irradiator 13 is determined by the voltage value of the X-ray transmission signal output from each X-ray detection element 14a of the X-ray line sensor 14 disposed below the belt. However, the X-ray dose irradiated by the X-ray irradiator 13 may be detected by the X-ray line sensor 14 disposed at another location.

(5-4)
In the above embodiment, the density for each article G is calculated. Here, based on the density data of the plurality of articles G, an average value of the densities may be obtained, and the average value may be used as the density of the articles G. Thereby, even if the planar shape of the inspection target article G and the planar shape stored in the control device 20 do not match, a relatively reliable value can be obtained.

10 X-ray inspection equipment (weight estimation equipment)
11 Shield box 12 Conveyor unit (conveyance unit)
13 X-ray irradiator (X-ray irradiation unit)
14 X-ray line sensor (X-ray detector)
14a X-ray detection element 20 Control device 21 Storage unit 21a X-ray image storage area 21b Basic shape information storage area (shape information storage area, association information storage area)
21c Identification shape storage area 21d Estimated information storage area 21e Density data storage area 22 Control unit 22a Image generation unit 22b Histogram creation unit 22c Plane shape identification unit 22d Weight estimation unit 22e Volume estimation unit 22f Density calculation unit 22g Quality determination unit 30 Monitor ( Input part)
70 Distribution mechanism 80 Line conveyor unit 90 Defective product collection line 100 Inspection line (X-ray inspection system)

JP 2002-296022 A

Claims (6)

An X-ray irradiation unit for irradiating the article with X-rays;
An X-ray detector that detects X-rays transmitted through the article;
An image generator that generates an X-ray image according to the intensity of transmitted X-rays detected by the X-ray detector;
A weight estimation unit for estimating the weight of the article;
A shape information storage area for storing shape information related to a plurality of three-dimensional shapes and a planar shape corresponding to the plurality of three-dimensional shapes;
Based on the shape information stored in the shape information storage area, a plane shape identifying unit for identifying a target plane shape which is a plane shape of the article corresponding to the X-ray image;
A volume estimation unit that estimates the volume of the article based on the three-dimensional shape corresponding to the target planar shape;
A density calculating unit that calculates the density of the article based on the weight of the article detected by the weight estimating unit and the volume of the article estimated by the volume estimating unit;
A density calculation apparatus comprising: The planar shape identification unit further identifies a major axis and a minor axis of the article based on the X-ray image,
The volume estimation unit estimates the volume of the article using the major axis and the minor axis specified by the planar shape identification unit, and an algorithm for obtaining volumes of the plurality of three-dimensional shapes.
The density calculation apparatus according to claim 1. The plurality of three-dimensional shapes include at least one of an ellipsoid, a cone, and a cylinder.
The density calculation apparatus according to claim 1 or 2. An input unit that accepts selection regarding the type of the target article;
An association information storage area for storing association information between the type of the target article and the planar shape;
Further comprising
The planar shape identifying unit selects the target planar shape that is the planar shape associated with the type of the target article according to the selection received by the input unit,
The volume estimation unit estimates the volume of the article based on the solid shape corresponding to the target plane shape selected by the plane shape identification unit.
The density calculation apparatus according to claim 3. The planar shape identification unit automatically selects the target planar shape from the plurality of planar shapes stored in the shape storage area based on the major axis and the minor axis.
The volume estimation unit estimates the volume of the article based on the solid shape corresponding to the target plane shape automatically selected by the plane shape identification unit.
The density calculation apparatus according to claim 3. The weight estimation unit estimates the weight of the article based on the X-ray image.
The density calculation apparatus in any one of Claim 1 to 5.