This application claims priority to Japanese Patent Application No. 2008-320096, filed on Dec. 16, 2008. The entire disclosure of Japanese Patent Application No. 2008-320096 is hereby incorporated herein by reference.
1. Field of the Invention
The present invention relates to an X-ray inspection apparatus that is capable of estimating the mass of an inspection target by radiating X-rays to the inspection target and detecting the X-rays that transmit therethrough, and then classifying the inspection target based on its mass.
2. Background Information
Known in the conventional art is an X-ray inspection apparatus that measures a physical quantity of a target of the inspection and determines whether that inspection target is good or bad. For example, Japanese Patent Application Publication No. 2006-308467 discloses one that is provided with an X-ray source, an X-ray detecting part, a data processing unit, a display unit, an area extraction processing unit, a mass calculation unit, and a display data generation unit. The area extraction processing unit extracts some of the detection information from the X-ray detecting part and thereby causes an X-ray image generating unit of the data processing unit to generate the X-ray image of a physical quantity measurement area at which the physical quantity is to be measured, at least a portion that corresponds to the background of the area being excluded on the X-ray image. Based on the detection information extracted by the area extraction processing unit, the mass calculation unit derives the physical quantity that corresponds to the size or the mass of a workpiece W. The display data generation unit associates and displays on the display unit the X-ray image of the physical quantity measurement area and a graph display element that indicates the physical quantity computed by the mass calculation unit.
In recent years, it has become desirable to use the measured physical quantity of an inspection target for purposes other than determining whether the inspection target is good or bad.
Taking the above problems into consideration, it is an object of the present invention to provide an X-ray inspection apparatus that is capable of being used to classify an inspection target based on the grade or class of its estimated mass.
An X-ray inspection apparatus according to one aspect of the present invention includes an X-ray radiating part, an X-ray detecting part, a mass estimation unit and a mass class determination unit. The X-ray radiating part is configured and arranged to radiate X-rays to an inspection target. The X-ray detecting part is configured and arranged to detect the X-rays radiated from the X-ray radiating part that transmitted through the inspection target. The mass estimation unit is configured to estimate a mass of the inspection target based on an amount of the X-rays detected by the X-ray detecting part. The mass class determination unit is configured to determine which mass class among a plurality of mass classes within a preset range the inspection target belongs to based on the mass of the inspection target estimated by the mass estimation unit.
Referring now to the attached drawings which form a part of this original disclosure:
Selected embodiments will now be explained with reference to the drawings. It will be apparent to those skilled in the art from this disclosure that the following descriptions of the embodiments are provided for illustration only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.
The following text explains an X-ray inspection apparatus according to an embodiment of the present invention, referencing the drawings.
An X-ray inspection apparatus 1000 shown in
As shown in
The conveyor 20 is provided and disposed such that it extends above the conveyor 30 from the corresponding X-ray inspection unit 10 through the interior of the shield box 2 and on to an end part of the conveyor 40. In addition, as shown in
The conveyor 30 transports the inspection targets 8 in a direction substantially perpendicular to the transport direction of the conveyors 20 toward the feeders 52a, 52c, 52e, 52g (i.e., the short types) and the feeders 52b, 52d, 52f (i.e., the long types). A plurality of the guide members 50 are provided in the transport direction such that they are suspended above the conveyor 30; furthermore, the guide members 50 form lanes 31-37, which guide the classified inspection targets 8 to the feeders 52a-52g.
The conveyor 40 is provided parallel to the conveyor 30 and transports the inspection targets 8 in the same direction as the transport direction of the conveyor 30. The two guide members 51 are provided in the transport direction such that they are suspended above the conveyor 40, and thereby the inspection targets 8 determined to be defective articles can be guided to the defective product collection box 54.
Each of the rejecter parts 60 includes: plate members 61, 62; and drive parts 64, 65, which are provided to a top plate 63 and, based on commands from the computer 7, are respectively capable of freely moving the plate members 61, 62 reciprocatively in the directions of the arrows shown in
As shown in
First, the foreign matter determination unit 80 will be explained. Referencing
The mass estimation unit 83 estimates the mass of the relevant inspection target 8 based on the amount of X-rays that transmit through this inspection target 8 and are detected by the X-ray detecting part 6 shown in
m=ct=c/μ×ln(I/I0)=α ln(I/I0) (1)
Here, c is a coefficient for converting the thickness of the substance to mass, t is the thickness of the substance, I0 is the brightness of the X-rays when there is no substance, I is the brightness of the X-rays after transmitting through substance, and μ is a linear absorption coefficient. In addition, α is a parameter that is assigned the value of c/μ; furthermore, an appropriate value for each type of the inspection targets 8 is derived in advance by performing pre-inspections using a plurality of samples with known masses, and those values are stored in the memory 72 shown in
For each of the pixels (i.e., for each of the X-ray detecting elements 6a), the mass estimation unit 83 uses the abovementioned equation (1) to convert the brightness I to the estimated mass m. Furthermore, while the conveyor 20 transports the inspection targets 8, the detection of the brightness I by each of the X-ray detecting elements 6a and the conversion of the brightness I to the estimated masses m are performed repetitively. Thereby, the estimated mass m is derived for every pixel of the relevant inspection target 8, and the estimated mass M of the entire relevant inspection target 8 is derived by summing all of these estimated masses m.
Based on the data S1 input from the mass estimation unit 83, the mass class determination unit 84 determines (1) which mass class of prescribed mass classes (for example, six levels which a prescribed range is divided into and which is set in advance for each type of the inspection targets 8, each level falling within the prescribed range) the mass of the inspection target 8 belongs to or (2) if the mass of the relevant inspection target 8 does not belong to any of the mass classes within the prescribed range, that the inspection target 8 is abnormal and outputs data S2 related to that determination result. The following text explains this more specifically. An upper limit value and a lower limit value of a target range (i.e., a permissible range) for each mass class is preset and stored in the memory 72 shown in
Based on the amount of transmitted X-rays detected by the X-ray detecting part 6 shown in
Based on the image data S3 input from the image generation unit 85, the shape determination unit 86 determines whether the shape of the inspection target 8 is normal or abnormal and outputs data S4 related to that determination result. Consider an example wherein data related to the upper limit value and the lower limit value of the perimetric length of a nondefective article is prestored in the memory 72 shown in
Consider another example wherein data related to the upper and lower limit values of the upper surface area of a nondefective article is prestored in the memory 72 shown in
Consider yet another example wherein image data of a template image related to the contour shape of a nondefective article is prestored in the memory 72 shown in
Consider yet another example wherein image data of a template image related to the size of a nondefective article that has a prescribed shape is prestored in the memory 72 shown in
Consider yet another example wherein image data of a template image related to the gray-scale pattern (e.g., of gray-scale peaks and gray-scale deviations) of a nondefective article is prestored in the memory 72 shown in
In the defect determination unit 87, the data S2 (i.e., the mass class or the abnormal state that was determined) is input from the mass class determination unit 84, and the data S4 (i.e., the normal/abnormal state of the shape) is input from the shape determination unit 86. Furthermore, based on the data S2, S4, if at least one of the determination results produced by the mass class determination unit 84 and the shape determination unit 86 is abnormal, then the relevant inspection target 8 is determined to be a defective article. Specifically, if the determination result produced by the mass class determination unit 84 is abnormal, then none of the rejecter parts 60 shown in
The present embodiment exhibits the following effects. Namely, the X-ray inspection apparatus 1000 provided by the present embodiment is capable of classifying the given inspection target 8 into one of the mass classes based on the estimated mass of the inspection target 8.
In addition, the X-ray inspection apparatus 1000 provided by the present embodiment is capable of sorting the abnormal inspection target 8 that does not belong to any of the mass classes because the mass class determination unit 84 can determine that the given inspection target 8 is abnormal. Therefore, the X-ray inspection apparatus 1000 can be provided that can be used to not only to determine whether the inspection target 8 is good or bad, but also to classify the inspection target 8 according to its estimated mass.
Furthermore, the X-ray inspection apparatus 1000 provided by the present embodiment is capable of sorting the inspection targets 8 into nondefective articles and defective articles based on their shapes because the image generation unit 85 and the shape determination unit 86 are provided. Thus, it is possible to provide the X-ray inspection apparatus 1000 that can not only be used to classify the inspection target 8 as a nondefective article or a defective article based on its shape, but also to classify the inspection target 8 into one of the mass classes based on its mass.
In addition, because the foreign matter determination unit 80 is provided, the X-ray inspection apparatus 1000 provided by the present embodiment is capable of not only easily selecting the inspection target 8 that contains uneatable foreign matter or the like, but also classifying the inspection target 8 into one of the mass classes according to its mass.
In addition, because the sorting unit 70 is provided, if the mass class determination unit 84 determines that the given inspection target 8 belongs to any one of the mass classes, then that inspection target 8 can be sorted into the corresponding mass class (specifically, into the corresponding lane of the lanes 32-37); furthermore, if the mass class determination unit 84 determines that the given inspection target 8 is abnormal, then that inspection target 8 can be sorted onto the conveyor 40 as a defective article. In addition, if the shape determination unit 86 determines that the shape of the given inspection target 8 is abnormal, then the sorting unit 70 can sort that inspection target 8 onto the conveyor 40 as a defective article; furthermore, if the foreign matter determination unit 80 determines that the given inspection target 8 contains foreign matter, then that inspection target 8 can be sorted into the lane 31 as a defective article.
Furthermore, it is understood that changes to the design may be effected without departing from the spirit and scope of the claims and that the present invention is not limited to the embodiments and modified examples explained above. For example, the X-ray radiating part 5 in the above embodiments radiates X-rays in one direction alone; however, a modification may be effected such that the X-ray radiating part 5 radiates X-rays to each of the inspection targets 8 from the same direction toward two or more locations of the inspection target 8, or from two or more directions toward at least one location of the inspection target 8, and the mass estimation unit 83 additionally estimates the mass of the useful portion of each of the inspection targets 8 based on the amount of X-rays detected by the X-ray detecting part 6; furthermore, based on the mass of the useful portion of the given inspection target 8 estimated by the modified mass estimation unit 83, the mass class determination unit 84 may determine which class, among the mass classes within a prescribed range set beforehand for each type of the inspection targets 8, the given inspection target 8 belongs to. Thereby, it is possible to classify the valuable useful portion of the given inspection target 8 according to its mass class, even if the contents of the inspection target 8 cannot be seen from outside. Here, examples of the useful portion of the given inspection target 8 include the edible portion of a fruit, vegetable, or shellfish, the egg yolk of an egg with shell, the egg yolk of a peeled hardboiled egg, a pearl that has grown inside a pearl oyster, and the edible portion of a frozen crab claw; however, the present invention is not limited thereto.
In addition, if the given inspection target 8 is, for example, a fruit or vegetable, then the shape determination unit 86 may determine, based on the X-ray transmission image, the presence or absence of a seed in the given inspection target 8. Furthermore, if the shape determination unit 86 determines that “a seed is present in the inspection target 8,” then the sorting unit 70 may sort that inspection target 8 as a defective article. Thereby, the given inspection target 8 can be classified as seeded or seedless. Namely, it is possible to easily select “seedless” products, which have added value.
In addition, instead of the rejecter parts 60, an air suction type rejecter part may be adopted, wherein the relevant inspection target 8 is suctioned and moved into a target lane.
In addition, guides may be provided at both ends of the plates 21 in the transport direction to provide assistance such that when the given inspection target 8 is pushed out by the relevant rejecter part 60 to the target lane, it is not transported mistakenly to a lane that is not the target.
In addition, the shape determination unit 86 is provided in each of the abovementioned embodiments, but it does not necessarily have to be provided. For example, it does not have to be provided if there is no need to classify according to shape.
In understanding the scope of the present invention, the term “comprising” and its derivatives, as used herein, are intended to be open ended terms that specify the presence of the stated features, elements, components, groups, integers, and/or steps, but do not exclude the presence of other unstated features, elements, components, groups, integers and/or steps. The foregoing also applies to words having similar meanings such as the terms, “including”, “having” and their derivatives. Also, the terms “part,” “section,” “portion,” “member” or “element” when used in the singular can have the dual meaning of a single part or a plurality of parts. Also as used herein to describe the above embodiment(s), the following directional terms “forward”, “rearward”, “above”, “downward”, “vertical”, “horizontal”, “below” and “transverse” as well as any other similar directional terms refer to those directions of an X-ray inspection apparatus. Accordingly, these terms, as utilized to describe the present invention should be interpreted relative to a device equipped with the X-ray inspection apparatus.
The term “detect” as used herein to describe an operation or function carried out by a component, a section, a device or the like includes a component, a section, a device or the like that does not require physical detection, but rather includes determining, measuring, modeling, predicting or computing or the like to carry out the operation or function. The term “configured” as used herein to describe a component, section or part of a device includes hardware and/or software that is constructed and/or programmed to carry out the desired function. The terms of degree such as “substantially”, “about” and “approximately” as used herein mean a reasonable amount of deviation of the modified term such that the end result is not significantly changed.
While only selected embodiments have been chosen to illustrate the present invention, it will be apparent to those skilled in the art from this disclosure that various changes and modifications can be made herein without departing from the scope of the invention as defined in the appended claims. For example, the size, shape, location or orientation of the various components can be changed as needed and/or desired. Components that are shown directly connected or contacting each other can have intermediate structures disposed between them. The functions of one element can be performed by two, and vice versa. The structures and functions of one embodiment can be adopted in another embodiment. It is not necessary for all advantages to be present in a particular embodiment at the same time. Every feature which is unique from the prior art, alone or in combination with other features, also should be considered a separate description of further inventions by the applicant, including the structural and/or functional concepts embodied by such feature(s). Thus, the foregoing descriptions of the embodiments according to the present invention are provided for illustration only, and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.
Number | Date | Country | Kind |
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2008-320096 | Dec 2008 | JP | national |