JPH0481232B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention is a technology applied to a bottle inspection device that inspects defects in bottles formed by a bottle molding machine, for example, and is particularly applicable to The present invention relates to a code reading device for determining the molding location of a defective bottle by reading a code indicating the molding location on the bottom of the bottle.

<Background of the invention> Generally, a bottle forming machine is equipped with a large number of molds.
These molds are used to simultaneously mold a large number of bottles. After the molded bottles have cooled, they are inspected for various defects using a bottle inspection device, and for bottles that contain defects, in order to investigate the cause of the defects,
You need to know which mold it was made in. Conventionally, all of this type of investigation has been carried out manually, which has resulted in the problem of extremely low work efficiency.

Therefore, in recent years, during bottle molding, binary codes representing the mold number are arranged in a circle with protrusions on the bottom of the bottle, and when a defective bottle occurs, the code attached to the bottle can be read. A method was proposed to identify the mold that produced the defective bottle. When implementing this method, for example, shine light from the mouth of the bottle,
The code is read from the bottom of the bottle while the bottle is rotated or stopped, but the molded bottle may be distorted or have dimensional errors, or misalignment may occur between the bottle and the reading unit. If this happens, there are problems such as the code becoming unreadable or reading errors occurring frequently.

<Object of the Invention> The present invention is intended to solve the above-mentioned problem, and an object thereof is to provide a code reading device that can read codes reliably and accurately.

<Structure and Effects of the Invention> In order to achieve the above object, the present invention provides an apparatus for reading and discriminating binary codes arranged in a circle, which includes an imaging device for capturing an image of the entire portion where the binary code is expressed. and a code discriminator that reads and discriminates the code by inputting the image obtained by the imaging section, and the code discriminator comprises two or more circles with different diameters on the image. means for setting, means for reading the image configuration data along each circle to determine the binary code, means for comparing the code reading data for each circle to determine whether or not the data match, and a means for determining the discrepancy. and means for rereading the image data along the set circle by moving the center point of the circle based on the set circle.

According to this invention, the data is adopted only when the code reading data for each set circle matches, and in addition, when the data does not match, the center point of the circle is moved and data reading is performed again. Therefore, even if there is distortion or dimensional error in the molded bottle, or if there is a misalignment between the bottle and the reading unit, there is a risk that the code will not be readable or a reading error will occur. This has the remarkable effect of achieving the object of the invention, such as making it possible to read codes reliably and accurately.

<Description of Embodiments> FIG. 1 shows the overall configuration of a bottle inspection device 1 incorporating a code reading device of the present invention.

The illustrated bottle inspection device 1 is provided in the middle of a bottle conveyance path 2, and a bottle forming machine (not shown) is located upstream of this bottle conveyance path 2. The bottle molding machine has a large number of molds and simultaneously molds a large number of bottles 50. During bottle molding, a code indicating the molding mold is formed on the bottom of the bottle, and the code can be read by reading the code. Now it is possible to determine which mold was used to mold the defective bottle.

The code is a multi-bit binary code,
As shown in FIG. 2, it is formed by integrally protruding a plurality of projections 3 on the bottom of the bottle and arranging them in a circle at a predetermined radius position r. In the illustrated example, the circumference is divided into 16 equal parts, and the positions indicated by ~ in the figure are code constituent bits, the positions indicated by are parity bits, the positions a to d are start bits, and the positions S ₁ to S ₃ are are respectively assigned to the reference bits. The code configuration bits for ~ correspond to "1" for the presence of protrusions and "0" for no protrusions, so these 8 bits allow a total of 256 types of codes to be set according to the mold number. There is. The parity bit of is used to determine whether the sign is correct or not, so that the sum of the "1" bits of ~ is an even number.
The start bits a to d are always "0", and the reference bits _S1 to _S3 are always "1", and these are used to detect the reading start position.

Note that each projection 3 in this embodiment is long in the radial direction and has a mountain-shaped cross section (see FIG. 3);
The shape is not limited to this, and may be formed in other shapes (for example, hemispherical). In addition, in the case of the illustrated example, θ in FIG.
By setting the inclination angle of the protrusion 3 (the maximum tangential angle if the inclined surface of the protrusion 3 is a curved surface) to 38 degrees or less, the light from below is effectively reflected downward and also upward. This makes it possible to read the code on the bottom of the bottle at the lower position, and inspect the bottle bottom at the upper position (for example, detect spots, bubbles, etc. on the bottom of the bottle).
Tests for detecting foreign substances) can also be carried out.

The bottle inspection device 1 includes a feed mechanism 6 that intermittently rotates a star wheel 5 having a plurality of recesses 4 on its circumferential surface, and a bottle inspection station provided at each stopping position of the recesses 4 (hereinafter referred to as an "inspection station"). A feeding mechanism 8 having a screw mechanism 7 for feeding a bottle 50 into each recess 4 is provided on the upstream side of the feeding mechanism 6, and a feeding mechanism 8 is provided on the downstream side of the feeding mechanism 6. A reject table 9 for recovering defective bottles is provided on the side.

In the illustrated example, there are five inspection stations indicated by A to E in the figure, and four of these inspection stations A to D are equipped with a bottle rotation mechanism 10 to inspect the bottle 50 in a rotating state. However, at the last inspection station E, the bottle 50 is inspected in a stationary state. Each bottle rotation mechanism 10
The rotating roller 11 is pressed against the circumferential surface of a bottle 50 located at an inspection station, and the bottle is rotated by the frictional force. Between each inspection station, there is a guide plate 12 that guides the bottle to the next inspection station. is in place.

The final inspection station E is equipped with a code reading device 13 for reading the code on the bottom of the bottle. As shown in FIG. 4, this code reading device 13 is disposed below a support plate 14 that supports the bottom of the bottle 50, and in the empty space above the support plate 14, for example, the height of the bottle, the height of the bottle, Caliber, degree of smoothness of bottle mouth,
An inspection machine 15 for inspecting bottle bottom defects and the like is installed to make effective use of space. The support plate 14
has a structure in which a resin plate 17 is stacked on a metal substrate 16, and the metal substrate 16 has a notch 18 corresponding to the bottle position, and the resin plate 17 has a tapered hole 19 opening downward. It is provided.

The code reading device 13 includes a ring-shaped light source 20 for projecting light onto the bottom of the bottle to effectively illuminate only the protrusion 3.
and a case 21 for storing this light source 20.
, a television camera 22 disposed inside the case 21 facing toward the bottom of the bottle to take an image of the bottle bottom, and a code discrimination circuit 23 that inputs the image obtained by the television camera 22 and reads and discriminates the code. It is configured.

The ring-shaped light source 20 is made up of two ring-shaped fluorescent lamps 24 and 25 arranged vertically in parallel, and the electrode portions of each fluorescent lamp that do not emit light are positioned diagonally, so that they cannot be projected onto the bottom of the bottle. It is designed to prevent uneven light. The case 21 that houses these fluorescent lamps 24 and 25 includes a housing 26 and a light source 2.
A transparent resin plate 28 is placed on the upper surface of this diffuser plate 27.
is in place.

FIG. 5 shows an example of the configuration of the code discrimination circuit 23. In the figure, a television camera 22 images the bottom of the bottle, converts it into an image, and stores this image in an image memory 29. The illustrated image memory 29 has a large number of pixels of 256 bits each in the vertical and horizontal directions, as shown in FIG.
Each pixel stores pixel data having a brightness level depending on the image. A monitor television 30 and a code reading circuit 31 are connected to the image memory 29, and the image memory 2
9 stored images can be visually confirmed.

The code reading circuit 31 reads each pixel data of the image stored in the image memory 29, performs processing such as binarization, and then reads the code data. This code reading circuit 31 is connected to a CPU (Central Processing Processing System) of a personal computer 32.
The CPU 33 is connected to the code reading circuit 31 based on the program in the memory 34.
In addition to executing various processes while controlling the operation of
It controls a series of operations from code reading to code discrimination.

FIG. 7 shows a specific circuit configuration of the code reading circuit 31. The code reading circuit 31 in the illustrated example has a circle (sixth circle) for reading the code on the image memory 29.
(indicated by broken lines R ₁ and R ₂ in the figure), and
A circuit unit 31A for sequentially specifying the XY coordinates of pixels located on this circle, and a circuit unit 31A for sequentially specifying the XY coordinates of pixels located on this circle, and two
Circuit section 31B for digitizing and reading codes
Each of the circuit units 31A and 31B is connected to the image memory 29 via an interface 35, respectively.

The circuit unit 31A has a function of setting multiple types of circles with different diameters and center points on the image memory 29, and uses XY coordinate data (in this embodiment, one A pair of coordinate data (360 pieces of coordinate data per circle information) are stored.
ROM (Read Only Memory) 36, 37 and each
Sequentially count the addresses of ROM36 and 37 and calculate XY
Preset counter 38 that outputs coordinate data
and adders 39 and 40 for moving the center point of the circle by a predetermined coordinate.

FIG. 8 shows n types of circle information F ₁ to _{F o} having different diameters stored in each of the ROMs 36 and 37, and any one of these pieces of circle information is sent to the personal computer 32.
When specified using the keyboard or the like, the preset counter 38 is preset with the starting address of the yen information.

FIG. 9 shows that when reading a code, the center point of the circle is moved in the order indicated by numbers 1, 2, 3, etc. in the figure (details will be described later), and this order and the moving coordinate distance are personal computer 3
8, it is automatically set.

The circuit section 31B includes a latch circuit 41 for holding pixel data read out from the image memory 29, and a comparator for comparing each latched pixel data with a predetermined threshold value and converting it into a binary value. 42 and
A gate signal generation circuit 43 forms 16 gate signals necessary for extracting a 16-bit code, and the binarized output from the comparator 42 is generated by the gate signal provided from the gate signal generation circuit 43. Code determination circuit 44 that reads, determines and extracts the code
and a shift register 45 that holds 16 bits of the output of the sign determination circuit 44 and outputs it to the microcomputer 32.

FIG. 10 is a diagram continuously showing pixel data on a circle read out from the image memory 29, where the horizontal axis shows the angle and the vertical axis shows the brightness level. In the figure, parts with high brightness levels correspond to protruding parts on the bottom of the bottle, and by comparing this pixel data with a predetermined threshold value TH in the comparator 42, a code as shown in FIG. Obtain the pulse signal that makes up the .

The gate signal generation circuit 43 includes an edge detection circuit 46 that detects the edge part e of the first pulse signal shown in FIG. The first gate 47 generates the gate signal G _i (where i is an odd number), and the gate width corresponding to the angle of 23 degrees. a second gate 48 that generates a gate signal G _j (where j is an even number), and a gate distribution circuit 49 that alternately supplies each gate signal to the sign determination circuit 44.
The gate distribution circuit 49 starts the distribution operation after a predetermined period of time has elapsed after the detection of the edge portion e.

Thus, the sign determination circuit 44 determines the sign depending on whether or not a prescribed number of logic "1" signals from the comparator 42 are present in the gate, and as a result,
Data in a 16-bit configuration is output bit serially, and this data is once stored in the shift register 45 and then taken into the microphone computer 32.

FIG. 12 shows the control flow of code reading and discrimination operations of this microcomputer 32, and FIG.
This shows the initial setting operation (shown as "ST1").

Prior to the bottle inspection, when you turn on the initial setting button located in the appropriate place on the device, the specified lamp will light up.
The start of the initialization process is announced (step 101,
102). Next, an image of the bottle bottom (for example, an image of a model for initialization) stored in the image memory 29 by the television camera 22 is captured and displayed on the monitor television 30 (step 103). Then, in the next step 104, when any circle information is selected and the radius of the circle is input and specified, the CPU 3
3, as shown in FIG. 6, draw a circle (for example, R ₁ ) on the image memory 29 with its center point P as the center;
This circle is displayed on the monitor television 30 together with the image (step 105). The images in the image memory 29 are taken into the monitor television 30 at regular intervals (for example, 1 second) and the screen display is updated.
If the circular array image of the protrusions 3 appears to be out of position with respect to _R1 , adjust the position of the television camera 22 while looking at this screen.

When the above-mentioned adjustments on the screen are completed and the initial setting button is turned off, step 106 becomes "YES", the lamp goes out, and the test waits for the start of the test.

Thus, the bottle inspection operation is started, and the bottle transport path 2
When the bottles 50 are fed into the respective recesses 4 of the star wheel 5, the bottles 50 are sequentially sent to the inspection stations A to E by the intermittent rotating operation of the feeding mechanism 6, and a predetermined inspection is carried out each time. When the bottle 50 reaches the final inspection station E and the inspection timing signal is input to the CPU 33, step 2 becomes "YES" and the code reading device 13 is activated in the next step 3.

If uniform light from the ring-shaped light source 20 passes through the diffuser plate 27 is irradiated uniformly onto the bottom surface of the bottle 50 that is stationary at the inspection station E, the light hitting the protrusion 3 on the bottom of the bottle will be reflected. Then, only the protrusion 3 shines brightly, and the other parts become dark. The brightness distribution at the bottom of the bottle is immediately imaged by the television camera 22, the image is stored in the image memory 29, and the code is read by the code reading circuit 31. In this code reading circuit 1, a first circle R ₁ (shown in FIG. 6) having a predetermined radius with the first center point (see FIG. 9) as the center of the circle is set; Reading of pixel data along the line and further reading is performed by hardware.

First, a predetermined preset counter value is given to the preset counter 38, and thereby each ROM3
6, 37 corresponding addresses to said first circle
360 pieces of XY coordinate data for setting _R1 are read out one after another along with the counting operation of the counter 38. Each of the following adders 39 and 40 has a ROM3.
The outputs of 6 and 37 and the center point correction value data from the CPU 33 are input and subjected to addition processing, but at this stage, the first center point (in FIG. 6, P
point) is set, each correction value is "zero".
It is.

Thus, each adder 39, 40 outputs XY
Pixel data is sequentially read out from the corresponding pixels in the image memory 29 based on the coordinate data and sent to the latch circuit 41.
It is set to . Next, these pixel data are binarized by a comparator 42 and then passed to a sign determination circuit 4.
4, and further sent to this sign determination circuit 44,
A gate signal generated by the gate signal generation circuit 43 is applied to read the code. As a result, if the reading is performed properly, the next step 4 is performed.
The determination is "YES", and the 16-bit read data is transferred from the shift register 45 to the CPU 33, and this transferred data is set in the memory 34 (step 5).

If the bottle is distorted or the bottle is misaligned, etc.
If the image of the bottom of the bottle is misaligned with respect to R ₁ , then 1
As a result, for example, two pulse signals are detected across two gates, the determination in step 4 "Is reading appropriate?" becomes "NO", and the process proceeds to step 11.

Regarding the data transferred in step 5, the following
First, in step 6, _the CPU 33 determines whether data corresponding to the start bits at positions a _to d in FIG. It is checked whether data corresponding to the bit exists, and whether the parity based on the position parity bit in FIG. 2 is correct in step 8. As a result, if all of steps 6 to 8 are "YES", the process advances to step 9, where it is checked whether or not this data reading is the second time.In this case, the determination is "NO". , proceed to step 10. Then, in step 10, the first
A _second circle _R2 having a different diameter from the circle R1 is set at the same center point as above, and the second code reading process is performed by the code reading circuit 31 based on the pixel data along the circle _R2 . executed. That is, in the code reading circuit 31, a preset value different from the previous one is given to the preset counter 38, and from this, each
The 360 XY coordinate data for setting the second circle R ₂ are read out one after another from the corresponding addresses of the ROMs 36 and 37 along with the counting operation of the counter 38 and are given to the image memory 29. Operations such as reading out pixel data from 29, binarization processing, and code determination are performed in the same manner as described above.

On the other hand, if the bottle bottom image is misaligned with respect to the first circle _R1 due to bottle distortion or bottle misalignment, either step 4 or 6 to 8 is determined. is “NO”, step
11, the second center point (see Figure 9) is set. Then, in the following step 12, the determination of "Have all center points been set?" is "NO", so in step 13, the first circle ₁ with the same radius as above is reset, and the pixel data along that circle _R1 is The code is read again based on this. In this case, in the code reading circuit 31, the center point correction value data ΔY is given from the CPU 33 to the adders 39, 40 in order to set the second center point. In the figure, pixel data is read out along a circle with point P' as the center point.

As a result of the second code reading process based on the second circle _R2 , if the reading is performed properly, the determination in step 4 is "YES".
Then, from the code reading circuit 31 to the CPU 3316
The bit read data is transferred and set in memory 34. Next, the CPU 33 performs steps 6~
8. As a result, steps 6 to 8 are executed.
If all are "YES", a further check is performed in step 9. In this case, since the determination in step 9 "Is this the second reading?" is also "YES", the process advances to step 14, where it is determined whether the first read data and the second read data match. be done. As a result, the judgment in step 14 is “YES”
When , the read data is judged to be appropriate,
The CPU 33 reads the code using the position of the start bit as a clue, and outputs the reading result to, for example, a higher-level controller (controller of the bottle inspection device).

On the other hand, if the determination in any one of steps 4, 6 to 8, and 14 is "NO", the next center point is set in step 11, and the same process is repeated.

In the example of FIG. 9, if proper data is not obtained even after setting the center point 57 times, the determination in step 12 is "YES" and step 16 is performed.
The error will be handled.

By reading the above code, it is possible to know the mold number of the bottle molding machine that molded each bottle 50, and if the correspondence between the defective parts of the bottle and the mold numbers is automatically tallied, the defective parts can be identified. Pursuits and corrections can be made quickly and appropriately.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an example of the overall configuration of a bottle inspection device, FIG. 2 is an explanatory diagram showing the symbols attached to the bottom of the bottle,
3 is a sectional view of the protrusion taken along the line of FIG. 2, FIG. 4 is a longitudinal sectional view showing an example of the configuration of the code reading device, FIG. 5 is a block diagram showing an example of the circuit configuration of the code reading device, and FIG. 7 is a block diagram showing a specific example of the code reading circuit, FIG. 8 is a diagram explaining the contents of the ROM in the code reading circuit, and FIG. The figure shows an example of setting the center point, Figure 10 shows pixel data read from the image memory, Figure 11 shows the timing of code reading operation, and Figure 12 shows the control flow of code reading operation. FIG. 13 is a flowchart showing the flow of initialization processing. 13... code reading device, 22... television camera, 23... code discrimination circuit, 31... code reading circuit, 32... personal computer, 33...
CPU, 34... Memory, 38... Preset counter, 36, 37... ROM, 39, 40...
Adder.

Claims (1)

[Scope of Claims] 1. A device for reading and discriminating binary codes arranged in a circle, comprising: an imaging unit for capturing an image of the entire area where the binary code is expressed; and a code discriminator that reads and discriminates the code by inputting an image, and the code discriminator includes two parts having different diameters on the image.
means for setting the above circles; means for reading image configuration data along each circle to determine the binary code; and means for comparing the code reading data for each circle to determine whether or not the data match. and means for re-reading image data along a set circle by moving the center point of the circle based on data mismatch determination. 2. The code reading device according to claim 1, wherein the binary code is configured with or without protrusions protruding at circular positions on the surface of the object. 3. The code reading device according to claim 1, wherein the imaging unit is a television camera. 4. The code reading device according to claim 1, wherein the code discriminator includes a computer circuit in its configuration.