JPS6252817B2 - - Google Patents

Description

[Detailed description of the invention] TECHNICAL FIELD The present invention relates to a method for inspecting bottle mouths, particularly bottle tops.

Generally, when new or reusing bottles,
For example, when beer bottles are reused in a factory, they are run on a conveyor to check whether there are any cracks or defects on the mouth of the bottle. However, conventional inspections for the presence of cracks in the openings of bottles are carried out by workers visually checking each bottle one by one, which requires a large number of workers and is labor intensive even though the work itself is monotonous. However, there was a problem in that continuing the work for a long time could cause considerable fatigue to the workers. Therefore, in order to solve the above problem, the applicant separately compared the number of rectangular waves that appear in the imaging signal obtained using a one-dimensional scanning camera, the difference in width, and the number of times a predetermined number of rectangular waves appear with reference values. We have filed an application for an inspection device that automatically performs inspections. Using these inspection devices, we were able to sufficiently check for cracks that normally occur, and some results were obtained. However, if a special cracking defect occurs, there is a risk that the check may not be completed. Therefore, an object of the present invention is to be able to check special crack defects that cannot be checked with the above-mentioned inspection device using a single scanning line.
An object of the present invention is to provide a method for inspecting the top surface of a bottle (hereinafter simply referred to as the bottle mouth) with higher precision.

In the bottle opening inspection method of the present invention, two scanning lines of a camera that scan the bottle opening to be inspected are arranged so as to intersect at an arbitrary angle in a relationship that crosses the bottle opening, and the scanning line obtained from these two scanning lines is This method is characterized in that two types of imaging signals are added to a signal processing circuit with the same function for inspection.

The present invention will be described in detail below with reference to embodiments shown in the drawings.

FIG. 1 is a schematic diagram showing an embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a conveyor on which bottles 2 to be inspected are placed and the bottles 2 to be inspected are transported in the direction of the arrow. 3
is a light source, and the light irradiated by this is reflected at the mouth of the bottle 2 to be inspected and directed toward the image sensor camera 4. Reference numeral 5 denotes a light source, and the irradiated light is also reflected from the mouth of the bottle 2 to be inspected and directed toward the image sensor camera 6. Image sensor cameras 4 and 6 (hereinafter simply referred to as cameras) are, for example,
A large number of CCD elements (charge coupled devices) are arranged,
This camera is capable of one-dimensional scanning, and when light hits these CCD elements, converts the optical signal into an electrical signal to obtain an imaging signal, and is itself a well-known camera. The light source 3 and the camera 4, and the light source 5 and the camera 6 are arranged so that their respective scanning lines crossing the bottle mouth are orthogonal to each other. The relationship between the mouth of bottle 2 and the scanning lines that cross it is shown in Figure 2. In FIG. 2, A is the scanning line of the camera 4, and B is the scanning line of the camera 6. 7 is a circuit that receives image signals from the cameras 4 and 6 and performs similar signal processing. The bottle neck is scanned by cameras 4 and 6 a sufficient number of times (per second) to detect cracks in the bottle neck.
Approximately 3333 times) sampling is performed at regular intervals.
The signal processing circuit 7 has a camera 4 and a camera 6, respectively.
The split defect detection is performed based on the number of imaging signals generated for each scan, that is, the mode aspect.

Here, mode refers to the rectangular wave obtained for each scan, and mode 1 means when there is one rectangular wave,
Mode 2 refers to the case of two rectangular waves. For example, in FIG. 1, if the bottle mouth is scanned using only the light source 3 and camera 4, and assuming that there is no breakage as shown in FIG. 3, until position A reaches scanning line A due to the movement of bottle 2, The light from the light source 3 is not reflected by the bottle 2. Therefore, no imaging signal is derived from the CCD element of the camera 4. In this case, the rectangular wave is naturally 0, so the mode is 0. As the movement of the bottle 2 progresses and the position A crosses the scanning line A, the CCD element near the end of the camera 4 catches the reflected light from the bottle 2, and as shown in FIG. 4A, each CCD element generates an individual pulse. derive the signal. This signal from the camera 4 is applied to a waveform shaping circuit included in the signal processing circuit 7, and this output is waveform shaped and is shown in FIG.
become that way. This waveform state, ie, the state with one rectangular wave, continues while the scanning line A exists between position A and position B, although the pulse width changes. All waveforms during this period are mode 1. When the bottle 2 continues to move and the position B crosses the scanning line A, the scanning line that crosses the mouth of the bottle 2 is divided into two parts. In this part, the output is derived from the CCD element of the camera 4 only at the part where the scanning line A crosses the bottle mouth, resulting in a signal as shown in Figure 4C, which is further shaped by the waveform shaping circuit and as shown in Figure 4D. Get a signal. This is the case in mode 2. The waveform obtained while the scanning line A exists at positions B and C is mode 2. Bottle 2 further moves, position C crosses scanning line A, and until position D reaches scanning line A, mode 1 continues as in the period from position A to position B, and bottle 2 moves further and positions When D exceeds scanning line A, no imaging signal is obtained and the mode becomes 0. The signal processing circuit 7 attempts to inspect the quality of the bottle by focusing on the fact that when there is a crack in the bottle, the mode status changes compared to a good bottle.
This is the role of

The signal processing circuit 7 may be of any type as long as it can detect cracks on the bottle mouth, but one example is to count the mode of the imaging signal obtained for each scan and determine whether the counted value is 2 or not. , 2, and performs bottle acceptability inspection processing based on whether the counted value of 2 is a predetermined value.

FIG. 5 shows the signal processing circuit described above.

In FIG. 5, 10 and 11 are AND gates, and the AND gate 10 is connected to receive the timing signal ta at one end of its input, and the imaging signal from the camera 4 at the other end.
is connected so that a timing signal tb is applied to one input end, and an imaging signal from the camera 6 is applied to the other input end. Timing signals ta and tb are timing signals for obtaining imaging signals from cameras 4 and 6 alternately for each scanning line. Further, the output terminals of the AND gates 10 and 11 are connected to a waveform shaping circuit 12. 13 is a mode counter that counts the rectangular wave of the waveform-shaped imaging signal from the waveform shaping circuit 12; 14 is a setting device that outputs a setting signal Ba="2"; 15 is a mode counter that receives the output of the mode counter 13 as an input. This is a comparator which receives the "2" signal from the setting device 14 at its other input and compares both of these input signals. The comparator 15 outputs "1" at its output terminal when the content of the mode counter 13 is "2". 16 is an AND gate which receives the timing signal ta as an input, derives the output of the comparator 15, and adds it to the mode 2 counter 17. The mode 2 counter 17 is provided to count the number of mode 2 scanning lines in the inspection of one bottle with respect to the image signal from the camera 4. 18 is an AND gate which receives the timing signal tb as an input, derives the output of the comparator 15, and adds it to the mode 2 counter 19. The mode 2 counter 19 is provided to count the number of mode 2 scanning lines in the inspection of one bottle with respect to the imaging signal from the camera 6. The output of the mode 2 counter 17 is connected to a decoder 20 so that it is displayed on a display 21, and the output of the mode 2 counter 19 is connected to a decoder 22 so that it is displayed on a display 23. 24 and 25 are AND gates, and the output of the mode 2 counter 17 and the timing signal Ta are connected to one end and the other end of the input of the AND gate 24, respectively. Further, the output of the mode 2 counter 19 and the timing signal Tb are connected to one end and the other end of the input of the AND gate 25, respectively. Timing signals Ta and Tb are timing signals that are generated alternately when one bottle is inspected. Reference numeral 26 denotes a setting device for setting a standard value for the number of pieces in mode 2 required as a non-defective product. A comparator 27 receives the outputs of the AND gates 24 and 25 at its other input end, and receives the signal from the setter 26 at its other input end. Comparator 27 is mode 2 counter 17 or mode 2
The output of the counter 19 is the reference value Bb from the setting device 26.
Outputs when the value is greater or less than . Comparator 2
The output of 7 is AND gate 28 and AND gate 29
connected to one end of the input. The other input end of the AND gate 28 receives the timing signal Ta, and the other input end of the AND gate 29 receives the timing signal Ta.
are connected so that Tb can be added to each. Further, the output of AND gate 28 is connected to the input terminal of latch circuit 30, and the output of AND gate 29 is connected to the input terminal of latch circuit 30. The output end of the latch circuit 30 is grounded through a light emitting diode 31 resistor. Similarly, latch circuit 30
The output end of the light emitting diode 32 is grounded through a resistor. The light emitting diodes 31 are turned on when the number of modes 2 for scanning line A is out of a predetermined value, and the light emitting diodes 32 are turned on when the number of modes 2 for scanning line B is out of a predetermined value.

Regarding the circuit shown in FIG. 5, we will now consider the operation when inspecting a bottle with a special crack defect as shown in FIG. First, the imaging signal is derived by the scanning line A of the camera 4 during the period during which the scanning line A exists between position A and position E in accordance with the movement of the bottle 2.

As the bottle 2 advances, when the position A reaches the scanning line A, a clock-like image signal is obtained from the camera 4 and is applied to the waveform shaping circuit 12 via the AND gate 10. The waveform shaping circuit 12 shapes this imaging signal into a rectangular wave and applies it to the mode counter 13. A mode counter 13 counts the number of rectangular waves, that is, the mode. Since there is a division deficit from position A to position B, the count value of the mode counter 13 is 2. Comparator 1
5, the value from the setter 14 is 2 and the value from the mode counter 13 is 2, so both inputs are equal and output "1". This output is applied to mode 2 counter 17 via AND gate 16. Since this operation continues while scanning line A is between positions A and B, the mode 2 counter 17 counts a value equal to the number of scanning lines between A and B. Next, when the scanning line A enters between A and C due to the movement of the bottle 2, there is no split loss during this period, and the state of mode 2 continues, and a number corresponding to the number of scanning lines during that period is counted by the mode 2 counter 17. To go. Furthermore, when scanning line A enters between positions C and D due to the movement of bottle 2, mode counter 1
The count content for each scanning line of 3 is 1. Comparator 15
Since the numerical value inputted to the setter 14 is larger, the output of the comparator 15 becomes "0". Therefore, the count value of the mode 2 counter 17 does not increase between C and D. During the period in which the scanning line A exists between the positions D and E, there is no splitting loss, so normal operation is performed. In the inspection of one bottle using the above scanning line A, there are periods (a) and (b) during which mode 2 is set instead of mode 1 due to splitting defects, and mode 2 is set to mode 2 when it should normally be mode 2 due to splitting defects. If the periods C and D are equal, as a result, the number of mode 2 scanning lines becomes zero. At timing Ta when all scanning ends, the count value of the mode 2 counter 17 is added to the comparator 27 via the AND gate 24. The comparator 27 uses the reference value from the setting device 26.
Bb is compared with the count value of the mode 2 counter 17, but since both are equal, the output "1" is not derived.
Therefore, since no signal is applied to the light emitting diode 31 via the AND gate 28 and the latch circuit 30, the light emitting diode 31 is not lit. Therefore, in the case of a special split defect as shown in FIG. 6, it cannot be detected by inspection using scanning line A.

On the other hand, the scanning of camera 4 is shifted by 90° and camera 6
Scanning is also performed in parallel. camera 6
The positional relationship between the scanning line B and the mouth of the bottle with the above-mentioned special split defect is as shown in FIG.

The imaging signal is derived by the scanning line B of the camera 6 according to the movement of the bottle 2 during the period when the scanning line B exists between position H and position W. Although the scans in periods H and W are slightly shifted from those in periods A and H by the same amount as the scan time difference between scan lines A and B, they proceed almost simultaneously.

In FIG. 5, the image signal obtained from the camera 6 is applied to the waveform shaping circuit 12 via the AND gate 11 at timing tb. During periods H and G of scanning line B, there is no difference from mode 1 with no split loss. During this period, the waveform shaping circuit 12 outputs one rectangular wave, so the mode counter 13 counts 1. However, the comparator 15 does not derive the output "1" because the output from the mode counter 13 is smaller than the signal 2 from the setter 14. Next, bottle 2
When the scanning line B enters periods 1 and 2 according to the movement of , mode 2 is entered because the bottle is broken. During this period, the waveform shaping circuit 12 outputs two rectangular waves, so the mode 2 counter 13 counts 2. Therefore, the comparator 15 outputs an output "1", and this output is applied to the mode 2 counter 19 via the AND gate 18, and the mode 2 counter 19 counts the number of mode 2 scanning lines. When the bottle 2 further moves and the scanning line B enters the gap, mode 3 becomes mode 3 due to a split loss, and the mode counter 13 counts 3, but the comparator 15 counts 3.
Since the output value from the mode counter 13 is larger than the signal of This output passes through an AND gate 18 to a mode 2 counter 19
added to. Also, although there is a split loss between position RI and position N, it is mode 2 and is no different from the case where there is no split loss. Furthermore, there is no difference between position N and position L, and there is no difference between mode 2 and the normal case. Further, when the scanning line B continues to move between positions L and O due to the movement of the bottle 2, mode 1 is set because there is a split defect. Therefore, no input is applied to the mode 2 counter 19 during this period. Furthermore, during the period in which scanning line B exists between position O and position W, there is no split loss at all, so the mode remains unchanged from the normal case. As a result, the value counted by the mode 2 counter 19 is compared to the normal case where there is no split loss, the number of scanning lines in periods G and C increases, and the number of scanning lines in periods L and O decreases, and the total number is significant. will be a small number. When the counting of one bottle is completed, the contents of the mode 2 counter 19 are changed to the timing
Tb is applied to the comparator 27 via the AND gate 25. The comparator 27 compares the numerical value from the AND gate 25 with the reference value Bb from the setter 26, and since the reference value Bb is larger, it derives an output of "1". This output passes through an AND gate 29 to a latch circuit 30.
is added to the input and held. This held output means that there is a crack in the test bottle, and this held signal is applied to the light emitting diode 32, which lights up to indicate that it is a defective bottle.

Therefore, for a bottle with a special cracking defect as shown in Figure 6, it may not be possible to detect it with scanning line A alone, but by inspecting it with another scanning line at a different angle, the cracking defect can be reliably detected. can do.

Note that in the above circuit example, the waveform shaping circuit, mode counter, comparator, etc. are used for processing the imaging signal of the scanning line A and the imaging signal of the scanning line B.
The same circuit may be separately provided for processing the image signal by the scanning line A of the camera 4 and the image signal by the scanning line B of the camera 6.

Furthermore, in the above embodiment, the processing circuit compares the number of scanning lines in mode 2 with a reference value, but
A circuit that determines the difference in signal width of two rectangular waves in mode 2 and checks whether the difference is greater than a certain value; A circuit that checks whether the number of modes is 3 or more;
It is also possible to use a circuit that checks based on the mode pattern of a continuous mode group of the same mode, or a combination thereof.

Furthermore, in the above embodiment, the cameras are arranged so that the scanning lines of the two cameras are perpendicular to each other.
The positions of the first camera and the second camera are shifted from each other with respect to the traveling direction of the conveyor, so that after scanning by the first camera, the scanning locus of the first camera with respect to the bottle opening crosses the scanning line. Scanning by a second camera may also be performed.

Further, the scanning line A and the scanning line B do not need to be orthogonal to each other, but may intersect at any angle.

Furthermore, the first camera and the second camera are arranged offset with respect to the traveling direction of the conveyor, and the direction of the scanning line of the first camera and the second camera is the same, and after scanning by the first camera, The bottle body may be rotated by an arbitrary angle (for example, 90 degrees) and then scanned by the second camera.

Furthermore, although two cameras are used in the above embodiment, only one camera is used, and after scanning the entire bottle opening, the bottle is rotated by an arbitrary angle (for example, 90 degrees), and the camera is also moved in the direction of movement of the conveyor to rotate the bottle opening. Two cross scans may be performed in different directions.

As described above, according to the inspection method of the present invention, two scanning lines are arranged at arbitrary angles, and two types of imaging signals obtained from these two scanning lines are added to a signal processing circuit with the same function for inspection. Therefore, it is possible to detect special damage, stains, scratches, etc., and to perform highly accurate inspections.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing one embodiment of the present invention, and FIG.
The figure is a diagram showing the positional relationship between the bottle opening and the scanning line A in the embodiment shown in FIG. 1, and FIG.
4 is a waveform diagram for explaining the operation using only the scanning line A, FIG. 5 is a circuit block diagram showing a specific example of the signal processing circuit of the embodiment in FIG. 1, and FIGS. FIG. 2 is a diagram showing the positional relationship between the bottle mouth and scanning lines for explaining the operation of the circuit block diagram. 2...
Bottle to be inspected, 4, 6...Camera, A, B...Scanning line, 7...Signal processing circuit.

Claims (1)

[Claims] 1. For bottles being transported in a single row by a conveyor, light is irradiated from above onto the top of the bottle, and the reflected light is directed at right angles to the direction of movement of the bottles to illuminate the entire top of the bottle. The number of rectangular waves that appear in the imaging signal for each scan obtained by scanning with the original scanning camera, the difference in their width, the number of times a predetermined number of rectangular waves appear, or the pattern of these waves are compared with a reference value to determine the top surface of the bottle. In the inspection method, the first scanning line that scans the top surface of the bottle and the scanning part that the first scanning line scans are in a relationship such that the scanning part intersects at an arbitrary angle. 1. A method for inspecting a top surface of a bottle, characterized in that two types of imaging signals obtained by these two scanning lines are added to a signal processing circuit with the same function for inspection. 2. The method for inspecting the top surface of a bottle according to claim 1, wherein the scanning line is obtained by arranging two cameras.