JPS6249927B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a bottle defect detection device that optically detects the presence and extent of scratches, bruises, cracks, and foreign objects on objects to be inspected such as beer bottles and youth bottles. Bottles used for beer, alcohol, soft drinks, food, etc. are collected from the market and reused. If the bottles are to be reused, they should be cleaned in advance using a bottle washer.
In addition to removing foreign matter such as dirt from empty bottles, it also removes damaged bottles. However, foreign matter such as dust that is firmly stuck to the inner surface of the bottle may not be completely washed away by the bottle washing device. Therefore, before or after the bottle washing process, bottles with such foreign substances or defective bottles with scratches or the like must be removed from the bottling line. Conventionally, this type of defect detection equipment has two types: one that inspects the body and the other that inspects the bottom.The one that inspects the copper part rotates the bottle to be inspected at high speed and irradiates it with light from the outside. The 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 continuously detects the presence or absence of defects in the entire body of the bottle to be inspected by taking the ratio of the amount of transmitted light between a certain area of the bottle to be inspected with and without defects. are being inspected. However, since such a detection device rotates the bottle to be inspected at high speed, the device itself becomes large and
In addition to high costs, defect detection accuracy 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 a food hygiene problem. In addition, when inspecting the bottom of a bottle, the lamp is generally illuminated from the direction of the bottom of the bottle, a television camera is installed above the bottle mouth, the optical image of the object to be inspected is photoelectrically converted, and this electric signal is sent to the scanning system of the television camera. They are sent out according to the following. However, since the bottom corner of the bottle is a place where there are many optical disturbances, it has been difficult to improve the accuracy of defect detection at the bottom corner of the bottle. That is,
As shown in FIG. 1A, the corner 2 of the bottle bottom 1 is connected to the bottle body 3.
The corner 2 has a certain curvature, the glass is thick, and in the case of a collection bottle, there are thin scratches on the bottom surface, so this corner 2 is a place where there are many optical disturbances. Furthermore, a small amount of washing water remains inside the bottle after the bottle washing process, and the diffused light from the bottom of the bottle undergoes total reflection at the meniscus of this washing water, reaching the light receiving device above the bottle mouth. Therefore, when looking at the optical image of the bottle bottom 1, a dark ring pattern may be formed at the corner 2. Because of the effects of such various optical disturbances, in the case of optical scanning of the bottle bottom 1 as shown in Figure 1B, the scanning electrical signal from the television camera corresponds to the corner 2 as shown in Figure 1C. The signal level in some areas becomes low. Particularly in the section AA', the overall signal level is low and the waveform is complex, making it difficult to distinguish between a normal signal and a signal whose light has been dimmed due to a defect. For this reason, in the past, electrical gates and mechanical masks were installed to exclude the part corresponding to corner 2 from the scanning range, and mechanical accuracy and machine wear-out required to pass the bottle to the fixed position were required. The reality is that only the area well inside the corner of the bottle is inspected, taking into account the drop in the bottle, the eccentricity of the bottle itself, etc. Therefore, an object of the present invention is to provide a defect detection device that does not have the above-mentioned drawbacks, and which performs image signal processing to reduce the influence of optical disturbances at the bottom of the bottle, thereby improving the accuracy of detecting defects at the bottom of the bottle. In addition to improving performance, the device is capable of high-speed processing and is inexpensive. This invention will be explained below. By the way, a television camera is generally used as an imaging device in defect detection equipment for glass bottles, etc., but the video signal transmitted by the television scanning method is affected by optical disturbances at the bottom corners of the bottles. As mentioned above, it is difficult to identify the defect signal in the part. Therefore, in the present invention, such video signals are rearranged and read out according to the shape of the object to be inspected, thereby making it easier to distinguish between normal signals and defective signals. That is, the optical image of the bottom of the bottle is as shown in FIG. 2, but the signal level between ST has a waveform as shown in FIG. 3. After this signal is once stored in the memory, when the stored signal is read out from the central part CP of the bottle bottom by a spiral scanning process as shown in FIG. 4A, the bottle bottom as shown in FIG. 4B is obtained. A gradual continuous signal can be obtained from the center to the bottom corner of the bottle. Therefore, if there is a signal change due to a minute defect in such a gradual continuous signal, it can be easily determined. FIG. 5 shows an embodiment of the present invention, in which a lamp 1 as a light source is placed below the bottom of an object to be inspected (for example, a beer bottle) 10 via a diffuser plate 11.
2 is provided, and a television camera 13 is provided above the bottle mouth. The video signal VS from the television camera 13 is amplified by the amplifier 14, and then converted to a digital signal (for example, 6 bits) DS by the AD converter 20, which is sequentially stored in the memory 30 according to the specified address. Ru. Further, the data stored in the memory 30 is read out according to the read signal RO from the memory control circuit 40,
This change in the read data is determined by the discrimination circuit 50 as the presence or absence of a defect or the degree of the defect, and when the defect signal DF is output from the discrimination circuit 50, the discharge device 60 removes the defective object 10 from the conveyor line. It is designed to be expelled. Here, the details of the memory control circuit 40 are shown in FIG. 6, and the address designation circuit 4
01 is driven and the write signal that will be output from now on
The 6-bit digital signal DS from the AD converter 20 is sequentially transferred to the memory 3 according to the specified address of WR.
Stored as 0. For example, as shown in FIG. 7, the memory 30 is configured to correspond to a 100×100 matrix corresponding to addresses 1 to 100 in the X direction and 1 to 100 in the Y direction. Images are stored as 6-bit digital values for each pixel. In this case, first specify Y=1 and specify the address from X=1 to X=100, then specify Y=2 and specify the address from X=1 to X=
Do this for 100. Thereafter, similar addressing is performed, and when all addressing is completed, the address designating circuit 401 outputs a write end signal FS, which is then output. This clock CL is input to an addressing memory (ROM) 403, which sends out a read signal RO to the memory (RAM) 30 for specifying an address according to Table 1 below. Note that Table 1 shows only an example of code conversion for a part of the central portion.

[Table] In this configuration, the lamp has a diffuser plate 1.
2, the object to be inspected 10 being transported by a transport means such as a conveyor is illuminated from the bottom direction of the bottle,
When the object to be inspected 10 reaches a predetermined position, an optical image of the bottom of the bottle is captured by a television camera 13, and one frame of the image is photoelectrically converted and a video signal VS is sent out. Then, this analog video signal VS is converted into, for example, a 6-bit digital signal DS by the AD converter 20 in accordance with its brightness, and is then converted into a 6-bit digital signal DS according to the address specified by the write signal WR from the address designation circuit 401. The data are sequentially stored in the memory 30 as shown in FIG. Once stored in the memory 30, the data is then read out from the addressing memory 403 by a pulse oscillator 402.
The contents of the RO are read out sequentially according to the address, but the addressing in this invention corresponds to the spiral scanning position from the center CP of the object to be inspected as shown in FIG. 4A according to the table in Table 1. Do this in sequence.
As a result, if there is no defect in the inspection object 10, the memory 30 outputs data with gradual changes as shown in FIG. 4B. If there is a defect in the inspected object 10, a sudden change will occur in the data read from the memory 30, so this is determined by the discrimination circuit 50 and discharged from the conveyor line via the discharge device 60. That's what I do. Note that although a case is described here in which the helical scanning is performed from the center CP of the object to be inspected 10, it is also possible to scan concentrically from the center CP. Incidentally, there may be cases where the image of the object to be inspected 10 cannot be captured at the center of the television camera 13 due to the accuracy or wear of the machine that transports the object to be inspected, or the eccentricity of the object to be inspected. In such a case, since the address specified by the memory control circuit 40 performs a spiral scan with the center of the screen as a reference, the signal read out from the memory 30 will not be gradual and will not reach the corner of the object to be inspected. This will result in the signal being mistakenly identified as a defective signal. Therefore, the corners of the object to be inspected are detected in advance, and the relationship between the object to be inspected 10 and the television camera 13 as shown in FIG. U+V)/2
It is necessary to calculate this center and correct the difference from the reference. An example of a circuit for realizing this is shown in FIG. That is, the reference voltage V
A comparator 41 is provided to obtain an end signal ES by comparing _r with the output of the amplifier 14.
From ES, an arithmetic circuit 42 obtains a vertical center signal CS, and an arithmetic circuit 43 obtains a horizontal center signal RS. These center signals CS and RS are then input to the address correction circuit 44, and the memory control circuit 40
The address, which is the content of the readout signal RO from the test object 10, is corrected, and spiral scanning is performed with the center of the object 10 as a reference. As described above, according to the defect detection device of the present invention, in order to remove optical disturbances at the corners of the object to be inspected, memory data is read by addressing by spiral scanning. Can make a judgment. Moreover, it has the advantage that high-speed detection is possible and the device is inexpensive. In the above-described embodiment, the light is irradiated from below and received above the object to be inspected, but it may be irradiated from above and received below. Further, as the television camera used for receiving (imaging) transmitted light, one equipped with an image orthicon, one equipped with a videcon, etc. can be used. Furthermore, in the above embodiment, the analog video signal is converted into a digital signal by an AD converter and then stored in the (digital) memory, but it is also possible to store the video signal as it is in the analog memory. It is possible.

[Brief explanation of the drawing]

Figure 1A is a cross-sectional view of the bottle bottom, Figure 1B is a diagram showing the relationship between the optical image of the bottle bottom and the scanning line, and Figure 1C is a diagram showing the relationship between the scanning direction and the signal level A-A', B-B. 2 is a diagram showing an example of an optical image of the bottom of the bottle, FIG. 3 is a diagram showing an example of the signal level between ST in FIG. FIG. 5 is a block diagram showing an embodiment of the present invention, FIG. 6 is a block diagram showing a detailed configuration example of a memory control circuit, and FIG. 7 is a block diagram showing a detailed configuration example of a memory control circuit. FIG. 8 is a diagram illustrating the address correction of the present invention, and FIG. 9 is a block diagram of a specific example of the configuration. DESCRIPTION OF SYMBOLS 1... Bottle bottom, 2... Corner, 3... Bottle body, 10... Test object, 11... Diffusion plate, 12... Lamp, 13... Television camera, 20... AD converter, 30... Memory, 4
0...Memory control circuit, 50...Discrimination circuit, 60...Ejection device.

Claims (1)

[Scope of Claims] 1. Defects in the object to be inspected are detected by irradiating light from below or above the object to be inspected and using video signals from an image pickup tube disposed above or below the object to be inspected. The apparatus includes: an AD converter that converts the video signal into a digital signal; a memory that stores the digital signal from the AD converter; a memory control circuit that reads data by sequentially specifying addresses corresponding to spiral or concentric scanning positions; and a memory control circuit that reads data by sequentially specifying addresses corresponding to spiral or concentric scanning positions; A defect detection device characterized by comprising a discrimination circuit for determining the presence or absence of a defect. 2. In an apparatus for detecting defects in the object to be inspected by emitting light from below or above the object to be inspected and using a video signal from an image pickup tube disposed above or below the object to be inspected, An AD converter that converts a signal into a digital signal, a memory that stores the digital signal from this AD converter, and an AD converter that stores the data stored in this memory in a spiral or concentric shape centered on the center of the object to be inspected. a memory control circuit that reads out data by sequentially specifying addresses corresponding to scanning positions of the object; The method further comprises: an address correction circuit for correcting a designated address; and a discrimination circuit for determining the presence or absence of a defect in the object to be inspected based on data changes read from the memory via the memory control circuit and the address correction circuit. Characteristic defect detection device.