JPH04118546A - Bottle inspection device - Google Patents

Abstract

PURPOSE:To enable a defect in the bottom section of a bottle to be detected quickly and accurately by detecting the defect through comparison between a processed image obtainable via light projection from the first light source capable of projecting light only to a bottle lower half section and the second light source capable of projecting light to a bottle bottom section, and another processed image obtainable via light projection only from the second light source. CONSTITUTION:A part of light projected from the first light source 4 passes while being reflected from the body section 3B of a bottle 3 (inspected bottle) to the bottom section 3A thereof. On the other hand, light projected from the second light source 7 is reflected at the surface of the bottle 3 such as bottom knurling. When image information obtainable via light projection only from the second light source 7 is eliminated from image information obtainable via concurrent light projection from the first and second light sources 4 and 7, only the reflection image of a defect is left, and a defect related to the bottom section 3A can be detected. According to the aforesaid construction, a defect in a bottom, particularly a defect in the bottom section of a bottle full of liquid as well as a defect in an empty bottle can be quickly and accurately detected. Also, automated defect detection can be embodied.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field 1] The present invention relates to a bottle inspection device, and more specifically, the present invention relates to a bottle inspection device that inspects a bottle bottom containing a substantially transparent liquid such as beer or juice [Prior Art 1] Generally, as described above, Due to cleaning errors, etc., some bottles may have deposits left on the inside of the bottle or large scratches, etc. Bottles with such defects naturally only reduce the product value. (This poses a major problem in terms of food hygiene and safety.Inspections for the presence of such defects have traditionally been carried out mainly by visual inspection; In this case, the results depend on the physical condition and ability of the inspector, and sometimes incredibly large defects may be overlooked.This type of visual inspection relies only on human vision, so it is difficult to detect defects. It is inevitable that many things will be overlooked.

Therefore, in recent years, various proposals have been made regarding devices for automatically detecting bottle defects, and some are actually commercially available as empty bottle defect detectors.

These mainly inspect the bottle body or bottle bottom, and those that inspect the bottle body (including the side of the bottle mouth) irradiate the bottle under inspection with light from one side while it is rotating at high speed. A CCD camera installed on the opposite side captures the transmitted image, converts it into an electrical signal, and uses an image processing device to determine the presence or absence of defects. In the case of inspecting the bottom of a bottle, illumination is applied from below the bottom of the bottle, the transmitted image is captured by a CCD camera installed above the mouth of the bottle, and this signal is digitized and image processed.

[Problem to be Solved by the Invention 1] However, the above-mentioned conventional bottle inspection devices mainly target empty bottles, and inspection of bottles after they have been filled with liquid has mainly relied on visual inspection. In particular, the bottom of the bottle has embossments, knurling, etc., which are difficult to identify as defects because they become shadows due to the phenomenon of light refraction, and treatment is required to remove these effects. This method of inspecting the bottom of empty bottles complicates the process and takes time.

In addition, a particularly serious defect in bottles after filling with liquid is when foreign matter is mixed in and floats or adheres to the bottle, and visual inspection shows that it has settled to the bottom of the bottle. Difficult to confirm.

Furthermore, in order to inspect defects on the bottom of the bottle by imaging them with the TV left camera from the side of the bottle body, image processing using several cameras is required, which is costly and time consuming.

An object of the present invention is to solve the above-mentioned conventional problems and to provide a bottle inspection device that can quickly and accurately detect defects present in empty bottles and liquid-filled bottles, especially at the bottoms of these bottles. It is in.

[Means for Solving the Problems 1] In order to achieve the above object, the present invention provides support means that supports the bottle so that light can be transmitted from the bottom of the bottle and limited to the bottom of the bottle, and a first light source that is capable of emitting light only from the lower half of the bottle body; a second light source that is disposed below the bottle bottom and capable of emitting light toward the bottle bottom; It is provided with an imaging means that is disposed directly below and is capable of converting optical information from the bottom of the bottle into an image signal, and an image processing means that processes an image based on the optical information based on the image signal from the imaging means. The image processing means generates a first processed image of the bottle bottom formed by light emitted from the first light source and the second light source, and a second processed image of the bottle bottom formed by light emitted only from the second light source. The present invention is characterized in that a defect related to the bottle bottom is detected from the difference by comparing the two.

Further, the supporting means is provided on a movable conveying means, and only a portion corresponding to the bottom of the bottle is transparent.

and a first light source capable of projecting light from the side of the plate body of the bottle to the lower half of the bottle body. a second light source disposed below the bottle bottom and capable of projecting light toward the bottle bottom; and a second light source disposed directly below the bottle bottom capable of converting light information from the bottle bottom into an image signal. an imaging means, a knurling part detection means for detecting a pixel position of the knurling part of the bottle bottom by comparing it with the second light source value, and an imaging means obtained using the first light source and the second light source. a first image processing means for erasing an image of the knurling part by erasing an image signal corresponding to a pixel position of the knurling part detected by the knurling part detection means from among the first image signals for one screen; and a second image processing means for detecting a defect related to the bottle bottom by comparing the first image signal obtained by erasing the image of the knurling portion with a prescribed second threshold.

Further, the present invention further provides a supporting means for supporting the bottle from below to the bottom of the bottle so as to allow light to pass therethrough; a first light source capable of projecting light; a second light source disposed below the bottle bottom and capable of projecting light toward the bottle bottom; and a second light source disposed directly below the bottle bottom and capable of emitting light from the bottle bottom. Using only an imaging means capable of converting optical information into an image signal, a level of a first image signal for one screen of the imaging means obtained using the first light source and the second light source, and the second light source. arithmetic processing means for calculating a pixel-by-pixel difference value with respect to the level of a second image signal for one screen of the imaging means obtained by the imaging means; knurling part detection means for detecting the pixel position of the knurling part at the bottom of the bottle by comparing the pixel position of the knurling part at the bottom of the bottle; By doing so, the first image processing means erases the image of the knurling part from the image indicated by the difference value for one screen, and the difference value of the image from which the image of the knurling part has been erased is 2
The apparatus is characterized by comprising a second image processing means for detecting defects related to the bottle bottom by comparing with a threshold value.

[For use] According to the present invention, the first light source illuminates the limited lower half of the bottle body from the side, and the second light source illuminates the bottom of the bottle from below. A first image of the bottle bottom is obtained, then the first light source is turned off and a second image of the bottle bottom is obtained using only the second light source. Look for the defects involved.

A part of the light emitted from the first light source is refracted and reflected from the bottle body to the bottom and passes through, whereas the light emitted from the second light source is reflected from surfaces such as the knurling at the bottom of the bottle.
When the image information obtained when only the second light source is irradiated is removed from the image information obtained when the second light source is irradiated at the same time, information on only the reflected image of the defect remains.

Further, by making only the portion of the support means that corresponds to the bottom of the bottle transparent, direct light projection of the first light source onto the imaging means is prevented.

Furthermore, since the present invention erases the knurling image from the first image to be inspected or from the subtracted image, the knurling portion will not be erroneously determined to be a defect. Further, when there is a change in brightness or density level between the images of the knurling part of the first image and the second image, the image of the knurling part which cannot be erased by the above-mentioned subtraction can be completely erased.

[Example 1] Hereinafter, an example of the present invention will be described in detail and specifically based on the drawings.

FIGS. 1A to 1C show an embodiment of the present invention. In this example, the conveyor belt is moved with the bottles to be inspected placed at predetermined positions on the conveyor belt, and when the bottles to be inspected are guided to the top of the imaging means (imaging camera 6), the bottles are successively placed one after another. The bottom of the bottle was then inspected.

In these figures, 1 is the conveyor belt, and 2 is a placement position (support part) where a bottle to be inspected (hereinafter simply referred to as a bottle) 3 is placed on the conveyor belt 1.

The parts of the belt 1 other than the supporting parts 2 are shielded from light by black matte IA, etc., and the plurality of supporting parts 2 are transparent or have openings formed so that the bottle bottoms 3A can be stably placed thereon.

Reference numeral 4 denotes a first beam irradiating the body 3B of the bottle 3 from both sides of the bottle 3 in a direction perpendicular to the moving direction of the belt 1.
A light source 5 is a light shielding plate that is provided between the first light source 4 and the bottle 3 and shields the upper half of the bottle 3 from light from the first light source 4 without interfering with the movement of the bottle 3.

These light shielding plates 5 prevent the light from the first light source 4 from being directly projected onto the embossing formed on the bottle body 3B or onto the liquid surface (not shown).

Reference numeral 6 denotes an imaging camera disposed below the conveyor belt 1 at the inspection position, such as a COD two-dimensional image camera, which can take an image toward the bottle bottom 3A when the bottle 2 is guided to the inspection position. The lens is facing upwards.

A second light source 7 is provided in a space between the imaging camera 6 and the conveyor belt 1, and is formed in an annular shape so as to surround the optical path from the bottle bottom 3A to the imaging camera 6.

In addition, the first light source 4 and the second light source 7 may be a general light bulb, a fluorescent lamp, a halogen lamp, a strobe, etc., and each may have a lifespan, luminous flux, brightness, stability, temperature characteristics, and spectral (wavelength) characteristics of the bottle 3. You can choose the appropriate one by considering the following.

Here, it is preferable that the brightness, position, direction, etc. of the light sources 4 and 7 can be adjusted according to the size (inspection accuracy) of the target defect to be detected. There are no set conditions, and the point is that the light may be projected so that the bottle bottom 3A is uniformly irradiated.

Further, for the imaging camera 6, the arrangement density and number of light receiving elements may be set in consideration of the spectral characteristics and inspection accuracy regarding the light sources 4 and 7 and the bottle 3, for example.

8 shown in FIG. 1C is an image processing device, which is mainly composed of a microcomputer and has ROM and RAM.
As will be described later, defects related to the bottle bottom 3A are detected based on an image of the bottle bottom 3A taken by the imaging camera 6.

In the bottle inspection device configured in this way, when the first light source 4 illuminates the bottle body 3B from both sides of the bottle 3 on the conveyor belt 1 that has been guided to the inspection position, the light is incident on the bottle body 3B. The emitted light passes through the bottle bottom 3A through refraction, scattering, and reflection, and is captured by the imaging camera 6.

At this time, the light shielding plate 5 shields the upper half of the bottle 3 where the embossing is formed from light from the first light source 4, so the light from the first light source 4 does not reach the embossing or the liquid surface. Therefore,
The light that is not mixed with reflected light and scattered light from these is reflected at the bottom of the bottle 3.
Although the light enters the imaging camera 6 through A, a knurling image is formed because some light passes through the outer surface of the bottle bottom due to reflection inside the bottle.

On the other hand, when the second light source 7 illuminates the bottom side of the bottle bottom 3A from the bottom side of the conveyor belt 1 with substantially uniform illuminance, a part of the illuminance is reflected by knurling or the like and captured by the imaging camera 6. Further, in this embodiment, by lighting the first light source 4 and the second light source 7 at the same time, the refraction and scattering at the knurling (slip prevention using a mesh-like embossed pattern) provided around the bottle bottom 3A can also be performed. A knurling image N is formed by reflection. At the same time, if there is a defect such as a crack or dirt on the bottle itself, a defect image is also formed, so an image of the bottle bottom (hereinafter referred to as the first image) as shown in FIG.
The image can be captured by the memory RAM of the image processing device 8.
Store in. Next, the second light source 7 is illuminated by only the second light source 7.
A bottle bottom image (referred to as a second image) as shown in Figure B is captured and similarly stored in the RAM.

Next, in the image processing device 8, the first image and the second image stored in the RAM are read out and subjected to arithmetic processing according to the procedure stored in the ROM. As for calculation processing, the first
After determining the difference for each corresponding pixel between the image and the second image (see Figure 2C), and binarizing it using a predetermined threshold, the difference is number), and if the total is equal to or greater than a preset value, the bottle is determined to be defective. Then, if necessary, this bottle should be removed from the conveyor belt 1 (a reject signal is output).

Note that the description of the position detecting means provided in connection with the conveying means, the defective bottle ejecting means, and their operations will be omitted in order to obtain the timing of imaging by the imaging camera 6. Further, by utilizing the fact that the first light source 4 shines on the bottle body 3B from opposite directions, the bottle 3 is rotated 90 degrees by a rotating means (not shown), and the image is taken again. It is preferable to uniformly inspect the entire bottle bottom 3A as this can further improve inspection accuracy. The configuration of the first embodiment and its detection method have been described above.
~50+n+n from the bottom of the bottle to remove minute defects of about 3mm square
When detecting in a range up to the height of the bottle body, the first light source, which is about 100 mm or more in height from the conveyor belt, is installed at a position about 30 to 50 mm away from the surface of the bottle body and irradiated with a predetermined illumination intensity. A ring-shaped high-frequency fluorescent lamp was prepared as the second light source. However, it was possible to obtain suitable detection results by adjusting the ratio of the amount of light at the bottle bottom 3A between the first light source 4 and the second light iJ7 to be about 1:2. However, when the first light source 4 and the second light source 7 are turned on, the light amount at the bottle bottom 3A may be adjusted to such an extent that it does not become saturated.

In this case, the imaging camera is equipped with a CCD 2 in which light receiving elements are arranged in a matrix with approximately 256 light receiving elements in both the vertical and horizontal directions.
A dimensional image camera was used. However, if it is desired to increase both inspection accuracy and inspection speed, a one-dimensional image sensor with high resolution and one scan time may be used.

3A to 3C show a second embodiment of the present invention.

In this embodiment, the second light source 7 is divided into two parts and arranged above both sides of the imaging camera 6, so that the bottle bottom 3A is lifted up from both sides. It can also be used as a stand. Further, the bottle 3 can be rotated by 90 degrees as shown by an arrow, for example, when the bottle neck is held by a rotating means (not shown). Note that the detection operation is the same as the previous embodiment, so a description will be omitted. However, this example assumes that the bottle 3 rotates, so it is necessary to use a ring-shaped second light source 7. There is no.

Figures 4A to 4C show a third embodiment of the present invention.

In this embodiment, the first light source 4 is an annular light source, and by providing the first light source 4 around the bottle body 3B near the bottom of the bottle, this part can be intensively irradiated. There is no need to rotate it. Regarding the detection operation, the first
Since this is not particularly different from that described in the embodiment, the explanation will be omitted.

Next, a fourth embodiment will be described in which the accuracy of erasing knurling images is improved.

FIG. 5 shows the circuit configuration of the image processing device 8 in this embodiment.

In FIG. 5, an image (video) signal of a luminance level for each pixel outputted from the imaging camera 6 is converted into a density level by a density conversion RAM 8B using a lookup table. The CPL 18A writes the image signal of the density level for one screen into the ROM 8D based on the system program stored in the ROM 8C.

When a video signal in the form of a density level representing a first image obtained using the first light source and the second light source and a second image obtained only using the second light source is stored in the RAM 4, the CPU 8A
performs processing for detecting defective parts of the object using the control procedure shown in FIG. Note that the control procedure shown in FIG. 6 is written in advance in a programming language and stored in the ROM 8C in advance.

In the second image, the density of the knurling part N appears high as shown in FIG. (Step 51 in Fig. 6)
00).

Next, all the density levels of the detected pixel positions of the knurling portion are converted to the maximum density level and updatedly stored in the RAM 8D (step 5ilo in FIG. 6). The video signal waveforms before and after density conversion at this time are shown in FIG. 7B.

Note that at this time, the CPU 8A operates as a knurling portion detection means of the present invention.

Next, the density level of the first image and the density level of the corrected second image are subtracted for each pixel (step 512 in FIG. 6).
0). The CPU IIIA at this time operates as the arithmetic processing means of the present invention.

Next, the density level of the pixel position where the subtraction result is negative, that is, the knurling part, is corrected to "0°", and the subtraction result for each pixel is stored in the RAM 8D (step 514 in FIG. 6).
0).

FIG. 7C shows an image and a waveform of the video signal as a result of the subtraction in which the image of the knurling portion has been erased in this manner.

Note that the CPU 8A at this time operates as the first image processing means of the present invention.

Next, the CPU 8A performs (second) threshold comparison or binarization processing on the video signal obtained by the subtraction, that is, the video signal in which the image of the knurling part has been erased, to determine the presence or absence of a defective part. (Step 5150 in Figure 6).

At this time, the CPU 8A operates as the second image processing means of the present invention.

As described above, in this embodiment, the pixel position of the knurling part is detected from the second image, and the image of the knurling part is erased based on the result of subtraction regarding the density levels of the first image and the second image. Therefore, even if the lighting environment changes,
Even if the density (brightness) of the knurling part in the image and the density (brightness) of the knurling part in the second image are not at the same level, the knurling part will not be erroneously determined to be a defective part.

In this embodiment, after subtracting the second image from the first image, the knurling image is further erased, or the knurling image is erased from the first image based on the pixel position of the knurling portion detected from the second image. After that, defective portions may be detected in this image.

In this case, after detecting the pixel position of the knurling part from the second image (signal) by the first threshold comparison process in step 5100 in FIG. (signal) is erased (initial value "0"). Next, a defective portion is detected by the second threshold comparison process of step 5150 in FIG.

[Effect of the Invention 1] As explained above, according to the present invention, by supporting the bottle on the support means, it becomes possible to transmit light only from the bottom to the bottom of the bottle, thereby reducing the limitation of the bottle body. A first light source emits light from the side onto the lower half of the bottle, and a second light source disposed below the bottom of the bottle emits light toward the bottom of the bottle. A first image of the bottom of the bottle is obtained by the method, the first light source is turned off, a second image of the bottom of the bottle is obtained using only the second light source by the imaging means, and the first image and the second image are compared by the image processing means. The system is designed to detect defects related to the bottom of the bottle from the difference between them, and detects not only empty bottles, but also the bottom of liquid-filled bottles, which traditionally relied heavily on visual inspection. The simple operation of switching the lighting and processing the image eliminates human-induced variations in inspection results, and enables automation, ensuring quality assurance and improving inspection speed and accuracy. Call.

Further, since the image of the knurling portion is completely erased from the image to be inspected, the knurling portion will not be mistakenly recognized as a defect.

[Brief explanation of drawings]

FIG. 1A is a front view showing an example of the configuration of the bottle inspection device of the present invention, FIG. 1B is a top view of FIG. 1A, FIG. 1C is a perspective view showing an example of the configuration of the present invention, FIGS. 2A, 2B 3A, 3B, and 3C are diagrams comparing and showing an example of a first image, a second image, and a defect detection image after image processing according to the present invention. 4A, 4B and 4C are a front view, a top view and a bottom view showing the configuration of the third embodiment of the present invention; FIG. is a block diagram showing the circuit configuration of the image processing device 8 according to the fourth embodiment of the present invention, FIG. 6 is a flowchart showing the execution processing procedure of the CPU 8A of FIG. 5, and FIGS. 7A, 7B, and 7c are the main FIG. 7 is a comparison diagram showing the waveforms of an image and a video signal obtained in the image processing process in the fourth embodiment of the invention. DESCRIPTION OF SYMBOLS 1... Conveyor belt, 2... Placement position (support part), 3... Bottle, 3A... Bottle bottom, 3B... Bottle body, 4... First light source, 5... - Light shielding plate, 6... Imaging camera, 7... Second light source, 8... Image processing device, 8A... CPU. 8B, 8D...RAM, 8C...ROM. N: Knurling image, D: Defect image. Figure 1A? llAl! 1 Shirakuni 1B diagram of the 11th -f column of the present invention? Country n+i Figure 1C Figure 28 Figure 2B Figure 20 Figure 8 Drawing 1 Table 1 Figure 5 Figure 6

Claims (1)

[Scope of Claims] 1) Supporting means that supports the bottle from below to the bottom of the bottle so as to allow light to pass therethrough; a first light source capable of emitting light toward the bottle bottom; a second light source disposed below the bottle bottom and capable of emitting light toward the bottle bottom; and a second light source disposed directly below the bottle bottom and capable of emitting light from the bottle bottom. comprising: an imaging means capable of converting optical information into an image signal; and an image processing means that processes an image based on the optical information based on an image signal from the imaging means; By comparing a first processed image of the bottle bottom caused by light projection with a second processed image of the bottle bottom caused by light projection only from the second light source through the image processing means, a difference between the two is determined. A bottle inspection device characterized by detecting related defects. 2) the support means is provided on a movable conveyance means;
The bottle inspection device according to claim 1, wherein only a portion corresponding to the bottle bottom is transparent. 3) a support means that supports the bottle so that light can be transmitted from below to the bottom of the bottle; and a first support that is capable of projecting light from the side of the bottle body of the bottle to the lower half of the bottle body. a second light source disposed below the bottle bottom and capable of emitting light toward the bottle bottom; a second light source disposed directly below the bottle bottom and converting light information from the bottle bottom into an image signal. By comparing the level of a second image signal for one screen of the imaging means obtained using only the second light source and the second light source with a predetermined first threshold value for each pixel, a knurling part detection means for detecting a pixel position of a knurling part; a first image processing means for erasing an image of the knurling part by erasing an image signal corresponding to a pixel position of the detected knurling part; A bottle inspection device comprising: second image processing means for detecting defects related to the bottle bottom by comparison with a threshold value. 4) Supporting means that supports the bottle so that light can be transmitted from below to the bottom of the bottle, and a support means that can project light from the side of the bottle body of the bottle to the lower half of the bottle body. a second light source disposed below the bottle bottom and capable of projecting light toward the bottle bottom; and a second light source disposed directly below the bottle bottom, converting light information from the bottle bottom into an image signal. convertible imaging means; and a level of a first image signal for one screen of the imaging means obtained using the first light source and the second light source, and a level of the first image signal of the imaging means obtained using only the second light source. arithmetic processing means for calculating a difference value for each pixel with respect to the level of the second image signal for one screen; and A knurling part detecting means detects the pixel position of the knurling part at the bottom, and the difference value obtained by the arithmetic processing means for the detected pixel position of the knurling part is converted into a numerical value "0", thereby converting the difference value for one screen. a first image processing means for erasing the image of the knurling part from the image indicated by the difference value; and comparing the difference value of the image from which the image of the knurling part has been erased with a predetermined second threshold value. and second image processing means for detecting defects related to the bottle bottom.