JPS6351264B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a foreign matter detection device that optically detects the presence and extent of scratches and foreign matter on objects to be inspected such as beer bottles and youth bottles.

Conventionally, there are two types of foreign object detection devices of this type: one that inspects the body and the other that inspects the bottom.The type that inspects the body rotates the bottle to be inspected at high speed and irradiates it with light from the outside. The transmitted light is detected by a photoelectric element inserted inside the bottle to be inspected. This detection device uses a photoelectric element as a detector, and calculates the ratio of the amount of transmitted light between a certain area of the bottle to be inspected with and without foreign objects (including scratches), and detects foreign objects in the entire body of the bottle to be inspected. Continuously inspects for the presence or absence of However, since such a detection device rotates the bottle to be inspected at high speed,
The device itself has become larger and more expensive, and the accuracy of detecting foreign objects is poor.Furthermore, since the photoelectric element is inserted into the inside of the bottle, there is a risk of contaminating the air inside the bottle, which poses food hygiene problems.

In addition, as another detection device, a television camera using a non-storage type image pickup tube is installed on the other side of the bottle to be inspected, which shines light from one side of the bottle being rotated at high speed. There is something I did. This mechanically detects the position of the bottle to be inspected,
This is designed to inspect the bottle to be inspected from the top to the bottom using one scanning line. However, since this detection device mechanically detects the position of the bottle to be inspected, errors in position detection are likely to occur, making it difficult to uniformly inspect the surface of the bottle to be inspected. In addition, since it is not possible to inspect two or more bottles at the same time with one television camera, it is not possible to speed up the inspection, and furthermore, since the bottles to be inspected are rotated at high speed, there are problems such as an increase in the size of the equipment and increased costs. It was hot.

For this reason, some systems are designed to rotate the bottles being inspected on a conveyor at low speed while illuminating them from the outside, and then inspecting the entire body of the bottle from the opposite side with a television camera. , This treatment method may cause the optical path length of the light passing through the bottle to be inspected to become longer or to be refracted at the edges of the bottle to be inspected, areas that are off-center, such as embossed letters or marks, uneven glass thickness, or seams. This phenomenon causes the area to become a shadow, resulting in a signal similar to that of a foreign object, making it difficult to perform accurate inspection.

Furthermore, it has been considered to use a storage type image pickup tube and a strobe as a light source for illumination, but it is limited by the afterimage of the image pickup tube, making it impossible to increase the speed, and the need to replace the strobe. The frequency of inspection has increased, and parts such as embossed characters, marks, seams, etc. that are off the center of the bottle being inspected cannot be accurately inspected, and the problem remains unresolved.

The present invention takes the above-mentioned points into consideration and provides a foreign object detection device that automatically determines an inspection area from a video signal of an object to be inspected such as a glass bottle, and performs a surface inspection of this area to obtain sufficient inspection accuracy. The purpose is to

Embodiments of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, reference numeral 10 is a light source incorporated in the foreign object detection device according to the present invention, and after light 11 from this light source 10 is uniformly diffused by a diffusion plate 12, it is sent to a conveyor (not shown). It irradiates the bottle 13 to be inspected, which is conveyed while continuously rotating above. The light passing through the inspection bottle 13 is focused by a condenser lens 14, and is converted into a two-dimensional photoelectric conversion device.
The light is input to a CCD (Charge Completed Device) 15. This CCD 15 has a separate synchronization signal generation circuit built in, and a large number of CCD elements 16.
(Figure 2). Each CCD element 16 is
As shown in FIG. 2, while being scanned in direction A along the axial direction of the bottle 13 to be inspected, overall scanning is performed sequentially from left to right (direction B) as shown by arrows a, b, and c. will be migrated. The video signal from each element 16 of the CCD 15 is amplified by a signal amplifier 18, and then a waveform shaping circuit (level detection circuit) 19 that shapes the waveform of the foreign substance signal in the video signal VS and detects the output level, and a bottle to be inspected. The bottle end detection circuit 20 detects the end of each bottle 13, and the bottle order memory circuit 21 stores the order of the bottles 13 to be inspected being transported to the inspection section. Of these, the waveform shaping circuit 19 has a signal level comparison circuit, and
A foreign object signal is detected and shaped from VS (Fig. 3), and this shaped video waveform signal VSA is sent to the gate circuit 2.
It is now sent to 3rd.

On the other hand, the bottle end detection circuit 20 detects the bottle end position of the bottle to be inspected 13 based on the video signal VS from the CCD 15, and inputs this detection signal DS to the inspection area signal generation circuit 24. The inspection area signal generation circuit 24 and the bottle end detection circuit 20 constitute an inspection area determination circuit, which determines the inspection area based on the bottle end detection signal DS from the bottle end detection circuit 20, and uses this inspection area signal RS. The signal is sent to the gate circuit 23 and the bottle order storage circuit 21. Specifically, the bottle end detection circuit 20 uses a differential comparator or the like to detect a significant change (in the direction of decrease) in the level of the video signal VS caused by the presence or absence of the bottle to be inspected, and uses it as a bottle end signal (FIG. 4). This signal is used to create a pulse DS (FIG. 5) with a constant time width using a one-shot multi-function device, etc., and is sent to the inspection area signal generation circuit 24. Based on the trailing edge of this pulse DS, an inspection area signal RS (FIG. 6) located approximately in the center of the bottle is generated. As shown in FIG. 2, this inspection area signal RS has a width corresponding to, for example, two rows of each element 16 along the axial direction of the bottle to be inspected of the CCD 15, and The central band-shaped portion along the axial direction of the test bottle 13 can be picked up as the test area (width). It should be noted that the delay time (pulse width) due to the above-mentioned one-shot multi can be determined as appropriate by adjusting the time constant of the capacitor C and the resistor R.
This makes it possible to target bottles of various sizes.

The gate circuit 23 to which the inspection area signal RS is sent gates and passes (picks up) only the signal corresponding to the inspection area signal RS out of the video waveform signal VSA from the waveform shaping circuit 19.
This waveform signal (pickup signal) GS is sent to the selection signal generation circuit 25. This sorting signal generation circuit 25 detects the video waveform signal GS sent from the gate circuit 23, determines whether the bottle to be inspected 13 is good or bad, and sends this discrimination (sorting) signal SS to the defective bottle storage and discharge signal generation circuit 26. It's becoming like that.

By the way, this defective bottle memory and discharge signal generation circuit 26 receives the bottle order signal from the bottle order memory circuit 21.
The OS is connected to be sent. This bottle order memory circuit 21 is configured to store a plurality of bottles 13 to be inspected at the same time.
When projected onto the CCD 15, it receives the synchronization signal included in the video signal VS and the inspection area signal RS from the inspection area signal generation circuit 24, stores the inspection order of the bottles 13 to be inspected, and stores the stored bottle order signal OS. is sent to the next bottle storage and discharge signal generation circuit 26. Defective bottle memory and discharge signal generation circuit 26
stores the presence or absence of the sorting signal SS from the sorting signal generation circuit 25 during the period when the bottle order signal OS is being sent from the bottle order storage circuit 21, and when the sorting signal SS reaches, for example, a predetermined value or more during that period, A discharge signal ES is issued, and when the bottle 13 to be inspected is conveyed to the discharge port position by this discharge signal ES, it is automatically removed from the bottle inspection line.

Next, the operation of this detection device will be explained.

The irradiated light 11 from the light source 10 is diffused to a uniform brightness by the diffuser plate 12 and irradiated onto the bottle 13 to be inspected, and the transmitted light is imaged by the lens 14 on the CCD 15 as shown in FIG. Since the transmitted light is subjected to a strong absorption effect while passing through the bottle 13 to be inspected, an image is formed with a large difference in light intensity between the transmitted portion and the other portions of the bottle 13 to be inspected. In addition, since the center and periphery of the bottle 13 to be inspected are affected by the refractive index and shape of the bottle 13 to be inspected, the center is bright and the periphery is dark, making it difficult to obtain such an optical image.
When converted into an electrical signal by the CCD 15, it is expressed as shown in FIG. As can be understood from FIG. 3, the output level of the video signal VS at the center of the bottle is relatively flat and almost constant, but the output level decreases toward both ends. Therefore, the change in the output of the video signal VS caused by the presence or absence of foreign objects attached to the bottle 13 to be inspected is large at the center of the bottle to be inspected, and decreases toward the periphery. It becomes nearly impossible to tell the difference. In addition, embossed characters, marks, etc. attached to the bottle 13 to be inspected,
The effects of uneven glass thickness and seams in the circumferential direction of the bottle are extremely small in the center of the bottle. This means that when light is irradiated from a direction perpendicular to the bottle surface of the bottle 13 to be inspected,
This is because differences in the amount of transmitted light due to unevenness in the thickness of the glass are small. When the light is irradiated obliquely or parallel to the bottle surface, the transmitted optical path length of the light increases, so a large amount of light is absorbed along the way, and the amount of transmitted light is greatly reduced due to refraction and the like.

Based on this relationship, in order to highly accurately and efficiently inspect foreign substances (including scratches) adhering to bottles to be inspected, it is necessary to use the CCD 15 (with a short repetitive scanning cycle).
It is necessary to make the scanning direction and the axial direction of the bottle 13 to be inspected point in substantially the same direction (parallel direction), and to limit the inspection area to the central area of the bottle to be inspected, which is indicated by diagonal lines in FIG. Therefore, the present invention can automatically determine the optimum inspection deposit area.

That is, as shown in FIG.
When the output level of the video signal VS suddenly decreases from a preset value at 0, a bottle end signal is generated. Based on this bottle end signal, a pulse waveform signal from a delay circuit (for example, one-shot multi), not shown, is received and an inspection area signal RS shown in FIG.
is generated by the inspection area generation circuit 24, this inspection area signal RS is applied to the gate circuit 23, and during that period, the video digital signal VSA from the waveform shaping circuit 19 is
The signal is passed through and sent to the selection signal generation circuit 25. That is, the gate circuit 23 passes only the video digital signal VSA corresponding to the inspection area signal RS and sends it to the sorting signal generation circuit 25, which sorts the video digital signal and generates the sorting signal SS when there is a foreign object. .

On the other hand, when a plurality of bottles 13 to be inspected are simultaneously projected on the CCD 15, a vertical synchronization signal is detected from the video signal VS sent to the bottle order storage circuit 21, and the inspection area signal generation circuit 24 uses this synchronization signal as a reference.
The inspection area signal RS from the
Serve. This generating circuit 26 detects in which bottle to be inspected the sorting signal (foreign substance signal) SS from the sorting signal generating circuit 25 is generated, and if there is a foreign substance in the bottle to be inspected, the bottle to be inspected is a defective bottle. When reaching the discharge port, the discharge signal generating circuit 26 is synchronized with the detection signal of the inspection bottle arrival detector installed near the discharge port.
The ejection signal ES is sent from the ejection mechanism (not shown).
is activated to remove defective bottles from the bottle inspection line.

In the explanation of the above-mentioned embodiment, the inspection area is set to be a central band-shaped portion along the axial direction of the bottle to be inspected, using the output level difference of the video signal VS that occurs depending on the presence or absence of the bottle to be inspected. As described above, depending on the shape of the bottle to be inspected, it may be possible to automatically detect only the direction perpendicular to the axial direction, or it may be possible to detect the entire area of the bottle to be inspected. .

In addition, the detection signal DS from the bottle end detection circuit 20 is
The change in the output level of the video signal VS may be detected from one CCD element where it first occurs, or may be detected from when the output level reaches a preset number of CCD elements. moreover,
As shown by A-A' in FIG. 2, the bottle end detection signal may be detected from a specific row of CCD elements along the vertical scanning direction (direction B).

Furthermore, the inspection area signal RS shown in FIG. 6 may be generated directly from the bottle end detection signal without intervening the pulse waveform signal shown in FIG. It may also be generated by synchronizing with a signal.

By the way, in the above description, we have explained the case where the inspection area is determined in the direction parallel to the axial direction of the bottle to be inspected to detect foreign substances. It can also be detected. In this case, the configuration of the part that irradiates and receives light onto the bottles to be inspected that are continuously conveyed on the conveyor is as shown in FIG. The diffuser plates 12 are respectively disposed, the diffuser plates 12 are respectively disposed, and the diffuser plates 12 are disposed respectively.
Transmitted light from a light source 10 provided below is made to enter a CCD 15 provided above a condenser lens 14. The processing after the output signal of the CCD 15 is amplified by the amplifier 18 is almost the same as the above-described inspection in the parallel direction. That is,
CCD1 incorporated in the foreign object detection device in this case
The bottle 13 to be inspected is imaged on each element 16 of 5.
The image becomes as shown in FIG. 8, and the video signal VS becomes as shown in FIG. In this case, a large change in the output level of the video signal VS is detected in the increasing and decreasing directions by the bottle end detection circuit 20 as shown in FIG. input. In the inspection area signal generation circuit 24, out of the bottle end detection signal DS, the video signal VS
is set at pulse P ₁ corresponding to the decreasing direction of
A signal that is reset by pulse _P2 corresponding to the increasing direction of the video signal VS is formed, and this is used as the inspection area signal.
RS (Figure 11). As a result, the bottle to be inspected 13
The inspection surface in the direction perpendicular to the axial direction of the bottle 13 can be determined, and foreign matter attached to the bottom of the bottle 13 to be inspected can be detected.

Note that in the above example, the light is irradiated from below the bottle to be inspected and the light is received at the top, but it is also possible to irradiate the light from above the bottle to be inspected and receive the light at the bottom. It is.

Further, in each of the above embodiments, a two-dimensional CCD is used as an example of the photoelectric conversion device, but a non-storage type image pickup tube may also be used. Also,
The object to be inspected is not necessarily limited to bottles and containers.

As described above, in the foreign object detection device according to the present invention, the image output signal from the photoelectric conversion device generated depending on the presence or absence of an object to be inspected such as a glass bottle is used to detect
Since the inspection area circuit automatically determines the inspection area in the direction perpendicular to or parallel to the axial direction of the object to be inspected, the optimum inspection area can be automatically detected and the inspection area can be automatically determined. The optimal inspection area surface of the inspection object can be effectively inspected. Therefore, the inspection speed of the object to be inspected can be improved, and the detection accuracy can be reliably improved.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the foreign object detection device according to the present invention, and FIG. 2 shows an image of a bottle to be inspected formed on each element of a photoelectric conversion device, such as a CCD, incorporated in the foreign object detection device. Figure 3 is a diagram showing the output level of the video signal from the photoelectric conversion device along line A-A' in Figure 2, and Figure 4 is a diagram showing the output level of the video signal from the photoelectric conversion device along line A-A' in Figure 2. FIG. 5 is a diagram showing the pulse waveform from a delay circuit such as a one-shot multi, FIG. 6 is a waveform diagram showing the inspection area signal from the inspection area signal generation circuit, and FIG. 7 is a diagram showing the pulse waveform from a delay circuit such as a one shot multi. A diagram partially showing another embodiment of such a foreign object detection device, FIG. 8 is a diagram showing an image of a bottle to be inspected formed on each element of a CCD incorporated in this detection device, and FIG. 10 is a diagram showing an example of the bottle end detection signal corresponding to FIG. 9,
FIG. 11 is a waveform diagram showing an example of the inspection area signal corresponding to FIG. 10. 10...Light source, 13...Bottle to be inspected, 15...
CCD (photoelectric conversion device), 16...CCD element,
19... Waveform shaping circuit (level detection circuit), 20
... Bottle end detection circuit, 21 ... Bottle order memory circuit, 23
...Gate circuit, 24...Inspection area signal generation circuit, 25...Selection signal generation circuit, 26...Defective bottle storage and discharge signal generation circuit.

Claims (1)

[Claims] 1. A photoelectric conversion device that forms an optical image of a continuously transported object to be inspected, such as a glass bottle, on a plurality of two-dimensionally arranged photoelectric conversion elements and converts it into an electrical signal. , a level detection circuit that detects the output level of the video signal from the photoelectric conversion device; an edge detection circuit that detects the edge position of the object to be inspected based on the video signal from the photoelectric conversion device; and detection by the edge detection circuit. an inspection area determination circuit that determines a predetermined inspection area based on the detected edge detection signal; and an inspection area determination circuit that picks up an output signal from the level detection circuit that corresponds to the inspection area signal determined by this inspection area determination circuit, and picks up the output signal from the level detection circuit to detect the target area. What is claimed is: 1. A foreign object detection device comprising: a sorting circuit that determines whether an object to be inspected is good or bad and outputs a sorting signal; and the presence or absence of a foreign object in the object to be inspected can be determined based on the sorting signal.