JPH08136467A - Defect inspection method and apparatus therefor - Google Patents

Abstract

PURPOSE: To prevent the occurrence of erroneous detection due to radiation of illuminating light for inspection at the time when defect inspection is automated by applying an image processing technology. CONSTITUTION: A defect inspection apparatus 1 is an apparatus provided with a light radiating means to radiate illuminating light to a resin pellet of an inspection part 5, a color CCD camera 7 to take an image of the pellet on the inspection part 5, an image processing means to carry out a prescribed image processing for the image taken by the camera, and a defect detecting means to detect the defect of the pellet based on the results of the image processing and the pellet is an opaque pellet. A pellet sending apparatus 2 to send a group of pellets on the inspection part 5 while arranging the pellets on the a conveying route and preventing them from overlapping mutually is also installed and at the same time the bottom part of the inspection part is made of a transparent glass plate 42 and the light radiating means is provided with an upper side illuminating lamp 6 to radiate illuminating light to the pellets from the upper side and a lower side illuminating lamp to radiate illuminating light to the pellets from the lower side of the transparent glass plate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to a group of a large number of inspected objects such as resin pellets and the like when a predetermined defect existing in the inspected object is detected by an image processing technique. The obtained defect inspection method and its apparatus.

[0002]

2. Description of the Related Art As is well known, when molding a synthetic resin product, it is necessary to use resin pellets of a designated color (or transparent) suitable for the color of the product as the molding material. When manufacturing pellets, defects such as so-called black spots and burns may occur in the pellets during the manufacturing process. When molding is performed using resin pellets having a certain number of such defects, a black line will appear in the final product and other problems will occur. For this reason, the resin pellets are inspected for the presence and degree of the above defects after their manufacture.

Conventionally, when this inspection is performed, a fixed amount is sampled from a group of resin pellets, and the sample pellets are given a predetermined size (for example, a diameter of about 20 to 30 mm and a thickness of about 1 mm) on a press machine. It is customary to form a sheet of the above sheet material and inspect the surface and back surface of the sheet material by an inspector. In this case, the front surface side and the back surface side of the plate material are each divided into a plurality of areas, the size of the defect is determined for each division and the number of defects is counted, and the size and the number are within a preset standard. Whether or not there is a sample pellet is visually determined, and based on this, whether or not the one group of resin pellets, which is the population, is determined. If the size of the above-mentioned black dots is larger than a certain size (for example, 0.05 mm ² or more), or if the number is small even if it is small, it appears as a black line in the final product and its commercial value is If the size or number of defects exceeds the reference value as a result of the inspection, the resin pellets of the manufacturing lot will be discarded.

However, in the above visual inspection by the inspector, the inspection efficiency and accuracy are limited, and moreover,
It is generally unavoidable that test results are affected by individual differences. Further, since it is necessary to prepare a press board and form the pellets into a plate material, there is a disadvantage that preparation for inspection takes time. Therefore, it is considered to apply a so-called image processing technique to automate and quantify the inspection, improve the efficiency of the inspection, and obtain a highly accurate and stable inspection result.

As is well known, a defect inspection using this image processing technique is basically obtained by imaging an object to be inspected with an image pickup means such as a CCD camera while irradiating the object to be inspected with light. The imaged image is subjected to predetermined image processing to inspect the object to be inspected for defects, and when applied to various colored objects such as the resin pellets described above, a color image extraction function is provided. Things are especially effective. As what can be applied to the defect inspection using such image processing technology,
The applicant of the present application, for example, in Japanese Patent Application No. 4-18772 or Japanese Patent Application No. 5-212260, extracts a color image that is registered in advance as a reference color from an image captured by a color imaging device. Proposed a device.

[0006]

By applying the image processing technique as described above, it is possible to directly inspect the resin pellets without the trouble of molding the sample pellets into a press plate or the like. If the pellet has defects such as black spots and burns, the size and number of the pellet can be automatically detected as a portion having a color different from the color of the pellet itself. However, when trying to automate the defect inspection by applying the image processing technology, there is a problem that false detection occurs due to the overlapping of pellets at the time of imaging or the influence of burrs at the end cuts at the time of pellet manufacturing. It was

That is, when an image of an object to be inspected (resin pellet) is taken by a CCD camera, the object to be inspected arranged on the inspection section of the inspection device is usually inspected from the same side as the camera (that is, the upper side). The object to be inspected is imaged within the field of view of the camera, but if there is overlap between the resin pellets on the inspection part, this overlap will become the shadow of the illumination light, resulting in a defective part. To be detected. Also,
The burr at the end of the pellet also produces a similar shadow, which is detected as a defective portion, and there is a problem that even if the resin pellet is normal and has no defect, it is erroneously detected as defective.

In addition, during the inspection, if ambient light is incident, the surface of the pellet has a shine different from that caused by the surrounding inspection illumination light, and it shines visually, which is mistaken as a defect. was there. Further, when the pellet is transparent, there is a problem that illumination light is reflected in the pellet, which adversely affects the defect detection. Further, if dust or foreign matter is attached to the pellet conveying path itself, there is a risk of misidentifying these as pellet defects.

The present invention has been made in view of the above problems, and when the defect inspection is automated by applying the image processing technique, erroneous detection may occur due to irradiation of inspection illumination light. A basic object of the present invention is to provide a defect inspection method and an apparatus therefor capable of effectively preventing the defect.

[0010]

Therefore, the invention according to claim 1 of the present application (hereinafter, referred to as the first invention) is directed to the inspection object on the inspection portion while irradiating the inspection object with illumination light. A defect inspection method in which predetermined image processing is performed on a captured image obtained by imaging, and a defect of the inspection object is detected based on the image processing result, wherein the inspection object is an opaque granular material. The body is a group of objects to be inspected are aligned on the transport path and fed onto the inspection unit while preventing overlapping, and the bottom of the inspection unit is formed of a light-transmissive bottom plate,
When the inspection object is imaged, the illumination light is applied from above the inspection object and at the same time, the illumination light is applied to the inspection object from below the bottom plate.

The invention according to claim 2 of the present application (hereinafter,
According to the second invention), predetermined image processing is performed on a captured image obtained by imaging the inspection object on the inspection unit while illuminating the inspection object with illumination light, and based on the image processing result. A defect inspection method for detecting a defect of the inspected object, wherein the inspected object is a transparent granular material, and the inspection is performed while aligning a group of inspected objects on a conveyance path to prevent overlapping. When the image of the inspection object is picked up, the illumination light is irradiated only from above the inspection object while the bottom of the inspection part is formed by a light diffusing plate or frosted glass. It is characterized by.

The invention according to claim 3 of the present application (hereinafter,
In a third invention), in the first or second invention, a monitor image is generated from the captured image, and other areas except a predetermined width area on the monitor image are masked to obtain the monitor image. The feature is that the defect detection of the inspection object is performed only in the upper predetermined width region.

Further, the invention according to claim 4 of the present application
(Hereinafter, referred to as a fourth aspect of the invention) In any one of the first to third aspects of the invention, the defect detection is performed while relatively moving the inspection object in a transport direction with respect to a transport path, When a defect is detected in the inspection object on the monitor image generated from the captured image, and the defect is not erased from the inspection target area of the monitor image even after a lapse of a predetermined time, the defect is detected by the inspection object. The feature is that it is determined that the object is not a defect.

Furthermore, the invention according to claim 5 of the present application.
(Hereinafter, referred to as a fifth invention), in any one of the first to fourth inventions, the inspection object is a resin pellet, the imaging is performed by a color imaging device, the image processing, It includes a color image extraction process that extracts a color registered in advance as a reference color from a color image, and is characterized by determining a defect when a color that does not match the reference color is detected. is there.

The invention according to claim 6 of the present application (hereinafter,
A sixth invention) is a light irradiation means for irradiating the inspection object on the inspection section with illumination light, an image capturing means for capturing an image of the inspection object on the inspection section, and a captured image obtained by the image capturing means. A defect inspecting apparatus comprising image processing means for performing a predetermined image processing, and defect detecting means for detecting a defect of the inspection object based on the image processing result, wherein the inspection object is an opaque granular material. A body is provided with a feeding means for aligning a group of objects to be inspected on a conveyance path and feeding them onto the inspection part while preventing overlapping, and the bottom part of the inspection part is a light-transmissive bottom plate. The light irradiating means includes an upper irradiating means for irradiating the inspection object with illumination light from above, and a lower irradiating means for irradiating the inspection object with illumination light from below the bottom plate. It is characterized by that.

The invention according to claim 7 of the present application (hereinafter,
According to a seventh invention), a light irradiation means for irradiating the inspection object on the inspection section with illumination light, an image capturing means for capturing an image of the inspection object on the inspection section, and a captured image obtained by the image capturing means. A defect inspection apparatus comprising image processing means for performing a predetermined image processing on the object, and defect detection means for detecting a defect of the inspected object based on the image processing result, wherein the inspected object is a transparent granular material. A body is provided with a feeding means for aligning a group of objects to be inspected on a conveyance path and feeding them onto the inspection section while preventing overlapping, and the bottom of the inspection section is made of a light diffusion plate or frosted glass. It is formed of a bottom plate, and the light irradiating means irradiates the inspection object with illumination light only from above.

Further, the invention according to claim 8 of the present application
(Hereinafter, referred to as an eighth invention) is, in the sixth or seventh invention, provided with monitor image generation means for generating a monitor image from the captured image, and has a predetermined width area on the generated monitor image. Masking is applied to other areas except for, and the defect of the inspection object is detected only in a predetermined width area on the monitor image.

Further, the invention according to claim 9 of the present application
(Hereinafter, referred to as a ninth invention), in any one of the sixth to eighth inventions, the defect detection is performed while relatively moving the inspection object in a transport direction with respect to a transport path,
The defect detection means, when a defect is detected in the inspection object on the monitor image generated from the captured image, if the defect is not erased from the inspection target area of the monitor image even after a predetermined time, The feature is that the defect is determined not to be the defect of the inspection object.

Further, the invention according to claim 10 of the present application
(Hereinafter, referred to as a tenth invention), in any one of the sixth to ninth inventions, the object to be inspected is a resin pellet, the image pickup means is composed of a color image pickup device, and the image processing means. Has a color image extracting function for extracting a color registered in advance as a reference color from a color image, and the defect detecting means determines a defect when a color that does not match the reference color is detected. It is characterized by that.

[0020]

According to the first aspect of the present invention, when the above-mentioned object to be inspected is fed onto the inspection section, it is arranged so as to be aligned on the conveyance path and prevented from overlapping, so that the inspection section can be fed. The inspected objects arranged on top of each other do not overlap, and when irradiated with the illumination light for inspection, the overlapped parts of the inspected objects are generated as in the past, and this becomes a shadow of the illumination light, resulting in defects. It is possible to prevent erroneous detection as a part. In addition, the bottom of the inspection unit is formed of a light-transmissive bottom plate, and when the inspection object is imaged, illumination light is emitted from above the inspection object and at the same time from below the bottom plate. Since the object to be inspected is irradiated with the illumination light, the object to be inspected is an opaque granular material, and even if the edge of the object to be inspected has a burr, the shadow due to the illumination light is erased and It is possible to effectively prevent the portion from being erroneously detected as a defective portion. That is, when the object to be inspected is an opaque granular material, it is possible to effectively prevent erroneous detection due to irradiation of illumination light for inspection when automating the defect inspection by applying the image processing technique. .

Further, according to the second aspect of the present invention, when the above-mentioned object to be inspected is fed onto the inspecting section, it is arranged so as to be aligned on the conveying path so as to prevent the overlapping, and therefore the inspecting section is fed. The objects to be inspected arranged on top of each other do not overlap, and when irradiated with illumination light for inspection, as in the conventional case,
It is possible to prevent a portion where the inspection objects are overlapped from each other, which becomes a shadow of the illumination light and is erroneously detected as a defective portion. Further, when the bottom of the inspection unit is formed of a light diffusing plate or frosted glass and the image of the inspection object is taken,
Since the illumination light is emitted only from above the inspected object, when the inspected object is a transparent granular material, even if the illumination light is reflected in the inspected object, the bottom of the inspection part is Due to the light diffusion plate or frosted glass, the reflected light inside the inspection object is diffused at the bottom of the inspection part and does not reach the imaging means, and the reflected light inside the inspection object adversely affects the defect detection. Is prevented. That is, when the object to be inspected is a transparent granular material, when automating the defect inspection by applying the image processing technique, it is possible to effectively prevent erroneous detection due to the irradiation of the inspection illumination light. .

Further, according to the third invention of the present application, basically, the same effect as that of the first or second invention can be obtained. In addition, masking is applied to other areas except the predetermined width area on the monitor image generated from the captured image, so that the defect detection of the inspection object is performed only on the predetermined width area on the monitor image. By narrowing the target area for defect detection, the influence of ambient light can be eliminated as much as possible, and false detection can be more effectively prevented.

Further, according to the fourth invention of the present application,
Basically, the same effect as any one of the first to third inventions can be obtained. Moreover, when a defect is detected while moving the inspected object relative to the transport path in the transport direction, and the defect is detected in the inspected item on the monitor image, the defect has passed for a predetermined time. Even if the inspection target area of the monitor image is not erased, the defect is determined not to be the defect of the inspected object. It is possible to effectively discriminate between the dust or foreign matter and the defect of the object to be inspected, and it is possible to more effectively prevent the occurrence of erroneous detection.

Further, according to the fifth invention of the present application,
Basically, the same effect as any one of the first to fourth inventions can be obtained. In particular, the image processing technique including the color image extraction process can be applied to the defect inspection of the resin pellet, and the inspection can be automated and quantified. As a result, it is possible to dramatically improve the efficiency of the inspection as compared with the case where the inspection is performed visually by an inspector, and it is possible to obtain a highly accurate and stable inspection result that is not affected by individual differences. .

Further, according to the sixth aspect of the present invention, when the object to be inspected is fed onto the inspection section, it is arranged by the feeding means on the conveying path so as to prevent the overlapping and to feed the object. Since it is possible to do so, the inspected objects arranged on the inspection part do not overlap with each other, and when the illumination light for inspection is irradiated, the overlapping parts of the inspected objects are generated as in the past. This can be prevented from being a shadow of the illumination light and being erroneously detected as a defective portion. Further, since the bottom of the inspection unit is formed of a bottom plate having a light-transmitting property, and the upper irradiation unit and the lower irradiation lower side are provided as the light irradiation unit, when the image of the inspection object is taken, The illumination light can be emitted from below the bottom plate at the same time as the illumination light is emitted from above the inspection object, and the inspection object is an opaque granular material, for example, the end portion of the inspection object. Even if there is a burr on the surface, it is possible to effectively eliminate the shadow caused by the illumination light and to prevent such a portion from being erroneously detected as a defective portion. That is, when the object to be inspected is an opaque granular material, it is possible to effectively prevent erroneous detection due to irradiation of illumination light for inspection when automating the defect inspection by applying the image processing technique. .

Further, according to the seventh aspect of the present invention, when the object to be inspected is fed onto the inspection section, it can be fed by the feeding means while being aligned on the conveying path to prevent overlapping. Since it is possible to do so, the inspected objects arranged on the inspection part do not overlap with each other, and when the illumination light for inspection is irradiated, the overlapping parts of the inspected objects are generated as in the past. This can be prevented from being a shadow of the illumination light and being erroneously detected as a defective portion. In addition, the bottom of the inspection unit is formed with a light diffusion plate or frosted glass,
When the image of the inspection object is taken, the illumination light is irradiated only from above the inspection object. Therefore, when the inspection object is a transparent granular material, the illumination light is emitted from the inside of the inspection object. Even if reflection occurs, because the bottom of the inspection part is made of a light diffusion plate or frosted glass, the reflected light inside the inspection object is diffused at the bottom of the inspection part and does not reach the imaging means. It is prevented that the reflected light in the object adversely affects the defect detection. That is, when the object to be inspected is a transparent granular material, when automating the defect inspection by applying the image processing technique, it is possible to effectively prevent erroneous detection due to the irradiation of the inspection illumination light. .

Further, according to the eighth invention of the present application, basically, the same effect as that of the sixth or seventh invention can be obtained. Moreover, masking is applied to other areas except the predetermined width area on the monitor image generated from the captured image by the monitor image generating means, and the defect detection of the inspection object is performed only on the predetermined width area on the monitor image. Since the target area for defect detection is narrowed down, the influence of ambient light can be eliminated as much as possible, and false detection can be more effectively prevented.

Further, according to the ninth invention of the present application,
Basically, the same effect as any one of the sixth to eighth inventions can be obtained. Moreover, in addition to performing defect detection while relatively moving the inspected object in the transport direction with respect to the transport path, the defect detection means, when a defect is detected in the inspected object on the monitor image,
When the defect is not erased from the inspection target area of the monitor image even after the lapse of a predetermined time, it is determined that the defect is not the defect of the inspected object. Even if dust or foreign matter on the transport path that does not move is indistinguishable from the defect of the inspection object itself, it is possible to more effectively prevent the occurrence of erroneous detection.

Furthermore, according to the tenth invention of the present application, basically, the same effect as that of any one of the sixth to ninth inventions can be obtained. In particular, the image processing technique including the color image extraction process can be applied to the defect inspection of the resin pellet, and the inspection can be automated and quantified. As a result, it is possible to dramatically improve the efficiency of the inspection as compared with the case where the inspection is performed visually by an inspector, and it is possible to obtain a highly accurate and stable inspection result that is not affected by individual differences. .

[0030]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings in the case where the present invention is applied to a defect inspection of resin pellets. 1 and 2 are an overall configuration explanatory view and a block configuration diagram schematically showing the configuration of a resin pellet defect inspection apparatus 1 according to an embodiment of the present invention, respectively. As shown in these figures, the defect inspection apparatus 1
Is a pellet feeder 2 composed of a parts feeder 3 and a rectilinear feeder 4 which will be described in detail later, and an illumination light from above to the pellet on the inspection unit 5 provided relatively far to the rectilinear feeder 4. Upper illumination lamp 6 for illuminating
As will be described later in detail, a lower illumination lamp 46 that irradiates the pellets on the inspection unit 5 with illumination light from below, and an image capturing image of the pellets on the inspection unit 5 illuminated by these illumination lamps 6 and 46. Color CCD camera 7 as a means
It has and. In the vicinity of the pellet feeding device 2 and the color CCD camera 7 (more preferably within a range of about 3 mm), a control panel 10 for controlling the operation of the defect inspection apparatus 1 is installed upright. The color CCD camera 7 is electrically connected to the control panel 10.

The pellet feeding device 2 has its lower end fixed on a base plate 9 having a substantially rectangular shape in a plan view, and is in the pellet feeding direction (see the arrow pointing left in FIG. 1).
A separate hopper 8 is attached diagonally above the parts feeder 3 located on the upstream side in FIG. The hopper 8 is loaded with resin pellets to be inspected by the defect inspection apparatus 1, stores the loaded pellets and supplies them to the parts feeder 3, and the loaded pellets are automatically fed to the parts feeder 3. When a predetermined amount of pellets supplied is supplied, an internal sensor (not shown) works to stop the supply. After that, when the pellets in the parts feeder 3 decrease to a certain amount or less, Pellets can be automatically supplied.
In this embodiment, an opaque resin pellet is supplied to the hopper 8 as the resin pellet to be inspected.

As shown in detail in FIGS. 3 and 4, the pellet feeding device 2 is configured by integrally connecting a parts feeder 3 and a straight-moving feeder 4, and the parts feeder is provided on the upstream side in the pellet feeding direction. 3 are arranged such that the linear feeders 4 are located on the downstream side.
The parts feeder 3 has a drive unit 22 fixed on the base plate 9, a controller 21 for controlling the operation of the drive unit 22, a supply port 23 for receiving the resin pellets supplied from the hopper 8. The transport unit 24 that feeds the received pellets to the straight feeder 4 side. The supply port 23 is formed of, for example, a cylindrical bowl having an upward diameter of about 200 mm, and the transport section 24 is formed in an arc shape of about ¼ circumference along the outer periphery of the supply port 23. . Further, the controller 21 is fixed to the base plate 9 and arranged laterally of the transport unit 24.

The straight feeder 4 has a base plate 9
A driving unit 27 fixed on the upper side, a controller 26 for controlling the operation of the driving unit 27, and a straight-moving conveying unit 28 which is smoothly connected to the conveying unit 24 of the parts feeder 3 and extends substantially straight in the horizontal direction. And the linear transport section 28.
The inspection unit 5 is provided on the relatively end side. Further, a pellet discharging unit 29 for discharging the inspected resin pellets from the straight-traveling conveying unit 28 to a terminal portion on the downstream side of the inspection unit 5.
Is provided. The straight feeder 4 is provided with a transport path 28a having a concave cross section along the longitudinal centerline of the straight transport section 28, and the resin pellets to be inspected are guided along the guide walls 28b on both sides. On the other hand, the paper is fed to the inspection unit 5 in the transport path 28a.

The parts feeder 3 and straight feeder 4
Although its internal structure is not specifically shown, it is the same as the one well known in the art, and applies minute vibrations of a predetermined amplitude and frequency to each of the transport sections 24 and 28. As a result, the pellets in the transport units 24 and 28 are continuously fed in a predetermined direction while being slightly vibrated, and a minute vibration is imparted by the parts feeder 3 so that a group of members to be inspected. The pellets are arranged in a predetermined number of rows (for example, about 1 to 5 rows). Then, the pellets in this aligned state are fed straight into the feeder 4.
It is fed to the inspection unit 5 while being subjected to microvibration in the straight-traveling transport unit 28 of the straight-traveling feeder 4. In the present embodiment, the parts feeder 3 and the straight-line feeder 4 have a microvibration frequency of, for example, 7200 times / minute.
(At 60 Hz) was used.

As described above, the group of pellets to be inspected is aligned by the action of the microvibration, and the pellets in the aligned state are constantly conveyed with the microvibration, so that the pellets are effectively prevented from overlapping each other. To be done. Therefore, when the illumination light for inspection is radiated to the pellets on the inspection unit 5, a portion where the pellets overlap with each other is generated as in the conventional case, and this becomes a shadow of the illumination light, which may be erroneously detected as a defective portion. It can be effectively prevented.

The color CCD camera 7 is composed of a camera body 31 and a camera lens 32. The camera body 31 is provided with a bracket 35 on the upper end of a vertical frame 34 provided upright on the base plate 9. , 36 are attached. The upper illumination lamp 6 for irradiating the pellet on the inspection unit 5 with illumination light from above is constituted by a ring-shaped fluorescent lamp having a predetermined diameter, and the center thereof is below the camera lens unit 32 in plan view. It is arranged so as to substantially coincide with the center of the camera lens section 32.

In the present embodiment, in order to prevent erroneous detection due to the influence of the shadow generated by the irradiation of the inspection illumination light, the pellets on the inspection unit 5 are not only lowered from above but also at the same time. The illumination light is also emitted from. That is, as shown in FIG. 5 and FIG. 6, in the straight-moving conveying section 28 of the straight-moving feeder 4, the bottom of the conveying path 28a is cut out in the region of the inspection section 5 so that the opening 41 having a substantially rectangular shape in plan view is formed. The opening 41 is provided with a transparent glass plate 42 as a light-transmitting bottom plate, and the glass plate 42 is provided with four pressing blocks 43 and the straight-line conveying unit 2 is provided.
It is fixed at 8. A partition guide 44 is fixed to both sides of the upper surface of the transparent glass plate 42 so as to have the same width as the guide wall 28b of the transport path 28. Further, on both sides of the straight-traveling transport unit 28, the pellets being transported are transported by the transport path 28.
A drop-prevention groove 45 is provided to prevent the spillage from a when it falls down to the outside of the rectilinear transport section 28.

As shown in FIGS. 1 and 4, a lower illumination lamp 46 for illuminating the inspection unit 5 from below is arranged immediately below the inspection unit 5. The lower illumination lamp 46 is composed of, for example, a straight tube type fluorescent lamp, and is fixed to the upper end of a pole 47 provided upright on the base plate 9. As described above, since the bottom of the inspection unit 5 is formed of the transparent glass plate 42 and the lower illumination lamp 46 is provided in addition to the upper illumination lamp 6, when the pellet on the inspection unit 5 is imaged. Since the illumination light is emitted from above the pellets, and at the same time the illumination light is emitted from below the transparent glass plate 42, the resin pellet to be inspected is opaque. Even if there is a burr at the end of the, the shadow due to the illumination light is erased, and it is possible to effectively prevent such a portion from being erroneously detected as a defective portion. When the lower side illumination lamp 46 is not a frosted glass such as a halogen lamp, the glass plate 42 at the bottom of the inspection unit 5 is preferably frosted glass.

As shown in FIG. 7, the control panel 10 is fixed to, for example, the upper end of a vertical frame 18 erected on the floor surface GL, and the panel surface has a color video monitor which will be described in detail later. 13, an operation panel 16 and a ventilation filter 17 are attached. Inside the control panel 10, as shown in FIG. 2, the color image extracting device 11 as the image processing means and the visual recognition device 12 as the defect detecting means described in claims 6 and 7 of the present application. When,
A color video monitor 13 as monitor image generation means according to claim 8 of the present application, an illumination power supply 15 for supplying power to the illumination lamps 6 and 46, and a sequencer 14 are provided.

The color image extracting device 11 is a color CCD.
The color registered in advance as the reference color can be extracted from the image captured by the camera 7, and the color video monitor 13 generates a monitor image from the image captured by the color CCD camera 7. The monitor image is recognized by the visual recognition device 12, and a color in the monitor image other than the defect of the pellet in the monitor image, such as a normal pellet color without a defect or a color of the partition guide 44 in the inspection unit 5, is used as a reference color. Register in advance. Further, more preferably, even if the pellet itself is normal without any defect, in order to cancel the influence of the shadow of the pellet that is inevitably generated during the movement, it is necessary to register the image during the movement of the pellet. It has become. The above control panel 10
Since the devices and equipment arranged inside are the same as those well known in the related art, the illustration and detailed description of the specific configuration thereof are omitted. For example, regarding the color image extraction device 11,

2. Description of the Related Art The one disclosed in Japanese Patent Application No. 4-18772 or Japanese Patent Application No. 5-212260 can be used.

Further, in this embodiment, in order to eliminate the influence of ambient light as much as possible, a predetermined masking process is applied to the monitor image generated from the image picked up by the color CCD camera 7. That is, as shown in detail in FIG. 8, in the monitor image of the color video monitor 13, a region other than the central predetermined width region 13c in the pellet advancing direction (vertical direction in FIG. 8), that is, the predetermined width region 13c. Masking is applied to the upper region 13a and the lower region 13b (see the hatched region in FIG. 8),
The pellet defect is detected only in the predetermined width region 13c. Thus, by narrowing the target area for defect detection, the influence of ambient light can be eliminated as much as possible, and the occurrence of false detection can be more effectively prevented.

In the above construction, the pellet feeding device 2
When the resin pellets are delivered to the inspection unit 5 in an aligned state by the, the illumination light is emitted from above and below by the upper and lower illumination lamps 6 and 46, and the color CCD camera 7 is illuminated from above and below both sides. The image is picked up by. As a result, a captured image in which the generation of shadows due to the irradiation of the inspection illumination light is effectively suppressed can be obtained. Then, the captured image is displayed on the color video monitor 13 of the control panel 10, and the defect inspection of the pellet is started. This inspection is performed by comparing a color on the monitor image recognized by the visual recognition device 12 with a reference color registered in advance, and determining whether the two match.

If they do not match, a black-and-white video signal having a different level is output. That is, when the pellet has a black dot, it is a color different from the registered reference color, and is detected as a defect, and the black and white video signal is output. The upper limit value and the lower limit value are set with the predetermined level of the black and white video signal as a reference value, and the detected defect is
When it is above the upper limit or below the lower limit, the sequencer 14 outputs an NG signal.

Further, in the present embodiment, the size of the defect of the resin pellet is set to four levels of defect area reference values a, b, c, d (a <b <c.
It can be classified into four ranks in <d), the number of defects in each rank can be counted, and further, the conveyance path 28a of the inspection unit 5 can be counted.
It is possible to identify the dust and foreign matter on the top and the defect of the pellet itself, and to issue an alarm when dust or foreign matter on the transport path 28a is detected. Next, the operation of the defect inspection apparatus 1 will be described with reference to the flowcharts of FIGS. 9 and 10. When the inspection starts, first in step # 1, in the window (that is,
Defects with defect area a ≦ S <b in inspection target area 13c)
It is determined whether (defect) has appeared. Here, S represents the defect area of the detected defect. If the determination result is NO, step # 1 is continuously repeated. In this example, the smallest defect area reference value a
Was set to 0.02 mm ² , for example.

The determination result in step # 1 is YES.
In the case of, in step # 2, from the inside of the window for a predetermined time
It is determined whether the defect is erased within (5 seconds in this embodiment). If the determination result is YES, the number of detected defects of rank 1 (defect area: a ≦ S <b) is incremented by 1. On the other hand, the determination result in step # 2 is NO.
In this case, it is determined that the detected defect is not the defect of the pellet itself but the dust or the adhering foreign matter existing on the transport path 28a, and the dust alarm is output in step # 4.

That is, since the pellets are detected while moving relative to the transport path 28a, when a defect is detected on the monitor image, the defect is detected in the inspection target area 13c set on the monitor image. If the inspection target area 13c of the monitor image is not erased even after the passage of a predetermined time (in the present embodiment, the predetermined time is set to 5 seconds as described above), the defect is in the pellet itself. It can be determined that it is not a defect. In this way, during inspection, it is possible to effectively discriminate between dust and adhered foreign matter on the transport path 28a that does not move even if the pellets move relative to each other, and a defect in the pellet itself, and more effectively prevent the occurrence of false detection. be able to.

The other three ranks, namely rank 2 (b
For ≦ S <c), rank 3 (c ≦ S <d), and rank 4 (d ≦ S), the inspection is performed in the same procedure as the above rank 1 except that the reference value for rank determination is different. (Rank 2: Step # 11 to Step # 14, Rank 3: Step # 21 to Step # 24, Rank 4: Step # 31 to
Step # 34). When the dust alarm is output, the inspection is temporarily terminated and reset in step # 51 (step # 52), dust and adhered foreign matters on the transport path 28a are removed, and then the inspection is performed again. Is about to start.

As described above, according to the present embodiment, when the resin pellet is an opaque type, when the defect inspection is automated by applying the image processing technique, it is caused by the irradiation of the inspection illumination light. Therefore, it is possible to effectively prevent erroneous detection from occurring. In particular, the image processing technique including the color image extraction process can be applied to the defect inspection of the resin pellet, and the inspection can be automated and quantified.
As a result, it is possible to dramatically improve the efficiency of the inspection as compared with the case where the inspection is performed visually by an inspector, and it is possible to obtain a highly accurate and stable inspection result that is not affected by individual differences. Of.

In the above-mentioned embodiment, the resin pellet is of the opaque type, but transparent pellets can be prevented from being erroneously detected by changing the illumination method during image pickup. it can. That is, when the pellet to be inspected is a transparent type, the bottom of the inspection unit 5 may be formed of a light diffusion plate or frosted glass, and the illumination light may be emitted only from above the pellet at the time of imaging. . The bottom of the inspection unit 5 can be made brighter by stacking the ground glass and the light diffusion plate from above.

By adopting such a structure, when the object to be inspected is a transparent pellet, even if the illumination light is reflected in the pellet, the bottom of the inspection section 5 is formed of a light diffusion plate or frosted glass. Therefore, the reflected light in the pellet is diffused at the bottom of the inspection unit 5 and the color CC
It will not reach the D camera, and the reflected light in the pellet will be prevented from adversely affecting the defect detection. That is, when the object to be inspected is a transparent pellet, when automating the defect inspection by applying the image processing technology, it is possible to effectively prevent erroneous detection due to the irradiation of the inspection illumination light. is there.

The present invention is not limited to the above-described embodiments, and within the scope of the invention,
It goes without saying that various improvements and design changes are possible.

[Brief description of drawings]

FIG. 1 is an overall configuration explanatory diagram of a resin pellet defect inspection apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram of the defect inspection apparatus.

FIG. 3 is a plan view of the defect inspection apparatus.

FIG. 4 is a front view of the defect inspection apparatus.

FIG. 5 is an explanatory plan view of a parts feeder and a straight advance feeder of the defect inspection apparatus.

FIG. 6 is a vertical cross-sectional explanatory view taken along the line AA of FIG.

FIG. 7 is a front explanatory view of a control panel of the defect inspection apparatus.

FIG. 8 is an enlarged front view of a monitor screen of the defect inspection apparatus.

FIG. 9 is a part of a flow chart for explaining the operation of the defect inspection apparatus.

FIG. 10 is a part of a flowchart for explaining the operation of the defect inspection apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Defect inspection device 2 ... Pellet feeding device 3 ... Parts feeder 4 ... Straight feeder 5 ... Inspection part 6 ... Upper side illumination lamp 7 ... Color CCD camera 11 ... Color image extraction device 12 ... Visual recognition device 13 ... Color video monitor 28a … Straight feeder transport path 42… Transparent glass plate 46… Lower side illumination lamp

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G06T 1/00 G06F 15/64 320 F

Claims (10)

[Claims] 1. A predetermined image processing is applied to a picked-up image obtained by picking up an image of the inspection object while illuminating the inspection object on the inspection unit with illumination light, and based on a result of the image processing, the inspection object is inspected. A defect inspection method for detecting a defect of an object, wherein the object to be inspected is an opaque granular material, and a group of objects to be inspected are aligned on a conveyance path to prevent overlapping and to be on the inspection part. While feeding, the bottom of the inspection unit is formed of a light-transmitting bottom plate, and when imaging the inspection object, at the same time as illuminating light from above the inspection object,
A defect inspection method comprising illuminating an object to be inspected with illumination light from below the bottom plate. 2. An object to be inspected on an inspection part is irradiated with illumination light, a predetermined image processing is applied to a captured image obtained by imaging the object to be inspected, and the object to be inspected is based on a result of the image processing. A defect inspection method for detecting a defect of an object, wherein the object to be inspected is a transparent granular material, and a group of objects to be inspected are aligned on a conveyance path to prevent overlapping while being on the inspection part. Along with the feeding, the bottom of the inspection unit is formed of a light diffusing plate or frosted glass, and when the inspection object is imaged, the illumination light is emitted only from above the inspection object. Defect inspection method. 3. A monitor image is generated from the picked-up image, masking is applied to a region other than a predetermined width region on the monitor image, and a defect of an object to be inspected is detected only in the predetermined width region on the monitor image. The defect inspection method according to claim 1 or 2, further comprising: 4. The defect detection is performed while relatively moving the inspection object in the conveyance direction with respect to a conveyance path, and a defect is detected in the inspection object on a monitor image generated from the captured image. If the defect is not erased from the inspection target area of the monitor image even after a predetermined time has passed, it is determined that the defect is not a defect of the inspection object. 3. The defect inspection method according to any one of 3 above. 5. The object to be inspected is a resin pellet, the image pickup is performed by a color image pickup device, and the image processing is
7. A color image extraction process for extracting a color registered in advance as a reference color from a color image, wherein a defect is determined when a color that does not match the reference color is detected. The defect inspection method according to any one of claims 1 to 4. 6. A light irradiation means for irradiating the inspection object on the inspection section with illumination light, an imaging means for imaging the inspection object on the inspection section, and a predetermined image on the captured image obtained by the imaging means. A defect inspection apparatus comprising image processing means for performing image processing and defect detection means for detecting defects in the inspected object based on the image processing result, wherein the inspected object is an opaque granular material. , A group of objects to be inspected are arranged on the conveyance path to prevent the overlapping, and a feeding means for feeding the objects to the inspection section is provided, and the bottom of the inspection section is formed of a light-transmitting bottom plate. The light irradiating means includes an upper irradiating means for irradiating the inspection object with illumination light from above and a lower irradiating means for irradiating the inspection object with illumination light from below the bottom plate. Defect inspection device. 7. A light irradiation means for irradiating an object to be inspected on the inspection section with illumination light, an image pickup means for picking up an image of the object to be inspected on the inspection section, and a picked-up image obtained by the image pickup means is predetermined. A defect inspection apparatus comprising image processing means for performing image processing and defect detection means for detecting defects in the inspected object based on the image processing result, wherein the inspected object is a transparent granular material. , A group of objects to be inspected are arranged on the conveyance path to prevent overlapping and are fed to the inspection unit, and the bottom of the inspection unit is formed of a light diffusion plate or a frosted glass bottom plate. The defect irradiating device is characterized in that the light irradiating means irradiates the object to be inspected with illumination light only from above. 8. A monitor image generating means for generating a monitor image from the picked-up image is provided, and masking is applied to an area other than a predetermined width area on the generated monitor image, and a predetermined area on the monitor image is provided. The defect inspection apparatus according to claim 6 or 7, wherein a defect of the inspection object is detected only in the width region. 9. The defect detection is performed while relatively moving the inspection object in a conveyance direction with respect to a conveyance path, and the defect detection means detects the inspection object on a monitor image generated from the captured image. When a defect is detected in the above, if the defect is not erased from the inspection target area of the monitor image even after a predetermined time has passed, it is determined that the defect is not a defect of the inspection object. Item 6
~ The defect inspection apparatus according to claim 8. 10. The inspection object is a resin pellet,
The image pickup means is composed of a color image pickup device, and the image processing means has a color image extracting function for extracting a color registered in advance as a reference color from a color image. 7. A defect is determined when a color that does not match the reference color is detected.
~ The defect inspection device according to any one of claims 9 to 10.