JP2001028034A - Method for reading metal mold number - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal mold number reading method which finds out the center position of a cord without being affected by an image of a projection other than the cord. SOLUTION: In this metal mold number reading method, the bottom 2 of a glass bottle 1 is photographed by an image pickup device 5 and the obtained image is processed by an image processor 6 to read a metal mold number out. In the image processing, the image is scanned radially from a set center to obtain the mean value of the angles to start points and end points of three projections and the minimum or maximum value of the distance from the center, the center of the circle passing three points of the obtained mean value of the angle and the maximum or minimum value of the distance is calculated, and the image is scanned radially from the found center to obtain the mean value of angles to the start point and end point of one projection; and the obtained mean value of the angle is regarded as an origin to obtain an array by searching whether or not there is a projection at each specified angle, and the metal mold number is specified on the basis of the obtained array.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for reading a mold number indicated by a code on the bottom of a bottle such as a glass bottle.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open Publication No. HEI 10-163566 discloses an apparatus for imaging a mold number indicated by a bar code or the like composed of a plurality of protrusions circumferentially arranged on the bottom of a bottle such as a glass bottle and reading the image by image processing. No. 657,892. Since the projections are arranged circumferentially, it is important to read the code because it is necessary to determine the center position of the circumference formed by the images of the plurality of projections.

In the above-mentioned patent invention, a concentric circle is set in advance so that all of the image of the projection is included between the concentric circles, and it is determined at which position the two circles are in contact with the image of the projection. By detecting the direction in which the center position is deviated, the center position is moved in the opposite direction, and the contact between the two circles and the image of each projection is checked again. The center is moved to a position where the image does not touch any of the two circles to determine the center position. Usually, on the bottom of the bottle, there are projections other than the code such as a company mark and a mold number (numeral) outside the projection showing the code.
Occasionally, projections other than these cords are inside.

[0004]

In the conventional method, when the bottle is largely displaced at the imaging position, the outer concentric circle and the image of the projection other than the code come into contact with each other, and the projection other than the code is mistaken for the code. There is a problem of recognition. For this reason, a new method for determining the center position is required. The present invention has been made in view of the above circumstances, and has as its object to provide a mold number reading method of determining a center position of a cord without being affected by an image of a projection other than the cord.

[0005]

According to the present invention, there is provided a method for reading a mold number represented by a code comprising a plurality of protrusions arranged circumferentially on a bottle bottom. In the mold number reading method of photographing the bottom of the bottle and processing the obtained image to read the mold number, the image processing scans the image radially from a set center to each of the three protrusions. The average value of the angle between the start point and the end point, and the minimum or maximum value of the distance from the center, and the center of a circle passing through three points consisting of the average value of the angle and the minimum or maximum value of the distance Is calculated, and the image is scanned radially from the obtained center to calculate the average value of the angle between the start point and the end point of one protrusion, and for each angle specified using the average value of the obtained angle as the starting point First, determine the array by searching for the presence or absence of protrusions, and find the mold number from the determined array. It is characterized in that.

According to the present invention, the center position of the code is directly calculated from the position data of the image of the projection indicating the code, and the image is scanned radially from the obtained center to search for the presence or absence of the projection and to arrange the array. To determine the mold number from the determined array, without being affected by the image of the protrusion other than the code, and improving the indexing accuracy of the center position, improving the mold number reading rate I do.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a mold number reading method according to the present invention will be described below with reference to FIGS. FIG. 1 is a schematic front view showing the configuration of an apparatus for carrying out the mold number reading method of the present invention. As shown in FIG. 1, an apparatus for carrying out a mold number reading method includes an illumination 3 and a Fresnel lens 4 installed below a bottle bottom 2 of a glass bottle 1.
And an imaging device 5 composed of a CCD camera installed above the glass bottle 1, and an image processing device 6 for processing an image obtained by the imaging device 5. The axis of the glass bottle 1 and the optical axis of the imaging device 5 are substantially perpendicular and coincide with each other.

In the above arrangement, when the bottle bottom 2 of the glass bottle 1 is illuminated by the light from the illumination 3 via the Fresnel lens 4, a part of the illuminating light passes through the bottle bottom 2 and passes through the bottle mouth. The light enters the imaging device 5. The image captured by the imaging device 5 is subjected to image processing by the image processing device 6. This image processing is performed in the following procedure.

In the image processing, as a step 1, a binary image is obtained from the image obtained by the imaging device 5. FIG. 2 is a diagram illustrating an example of a barcode, and illustrates a binary image obtained by binarizing an image obtained by the imaging device 5 into a bright image and a dark image by the image processing device 6. However, in FIG. 2, the image of the protrusion other than the cord is omitted. In FIG. 2, S, M, 3, 4, E, 7, P
The bar (dark portion) at the position is an image of the protrusion indicating the code. The bar code is obtained by dividing the circumference into 16 parts.
The bars at the positions of S, M and E are fixed. That is, every mold number has these bars. P is parity. The position of X is fixed and there is no bar for any mold number. S is the start position of the number reading, and the mold number is represented by an 8-bit binary number from 0 to 7. The arrangement of the bars is read in a counterclockwise direction to specify the mold number. The bar at the position S is called a start bar. Assuming that the presence or absence of a bar is 1,0 in a binary number, FIG. 2 shows S MEP 100011110101110,000, and shows 152 in a decimal system. That is, S, M, E,
Calculating by excluding 1 in P, the next to M and its next are 1 respectively, 2 ³ = 8, 2 ⁴ = 16, and the two ahead of E are 1
Where 2 ⁷ = 128, for a total of 152.

Next, in the image processing, as step 2, the image is scanned radially from the set center, and the average value of the angle between the start point and the end point of each of the three protrusions (bars) and the distance from the center Find the minimum value of. FIG. 3 is a diagram showing this stage, which is performed in the following procedure. 1) An image is scanned in a counterclockwise direction (θ direction) radially (r direction) from a center C _T (x _T , y _T ) set at the center of the screen. Set the concentric _R 1, _{R 2} centered on C _T, the portion between the _{R 1} and _{R 2} and the scan region. If there is a protrusion other than the code outside the barcode, make the outer circumference of the scanning area smaller than the outer circumference of the barcode and make the inner circumference of the scanning area the inner circumference of the barcode so as not to be affected by anything other than the code. Smaller than Then, the image data (bright and dark) is read from the inner circumference to the outer circumference on the scanning line.

2) First, a gap between the bars is found. The gap is when there is only light on the scanning line. In FIG. 3, θ
The position at = 0 ° is a gap. If a gap is found, continue scanning and find the first bar (B ₀ ). The angle of the scanning line that changes from light to dark on the scanning line is the angle of the starting point (θ
_0S ). The angle of the scanning line immediately before the scanning line (gap) where the change from light to dark has disappeared is the angle of the end point (θ
_0E ). (Θ _0S + θ _0E ) / 2 is the average value (θ ₀ ) of the angle between the start point and the end point. Since the inner circumferential side reads the image data toward the outer periphery, when implicitly changed from the bright scan line, plus R ₁ is the distance from the center C _T up bar on the number of pixels the bright up it. Therefore, from θ _0S to θ
Minimum value of the distance from the center C _T plus R ₁ to the minimum value of the number of pixels the bright which has been stored in the scanned between until _0E (r
₀ ).

3) The image is scanned from an angle advanced by 70 ° from the angle (θ _0S ) at which the first bar (B ₀ ) was found.
Continue scanning and find the second bar (B ₁ ). B ₀
As in the case of ( ₁ ), the average value (θ ₁ ) of the angle between the start point and the end point of the bar (B ₁ ) and the minimum value (r ₁ ) of the distance from the center are obtained. As will be described later, it is desirable that the three bars are separated from each other in order to find the center of a circle passing through three points formed by the three bars. The arrangement of the bars in this embodiment is 90 °
There are fixed S, M, and E bars at positions away from each other, and the circumference is divided into 16 (1 division = 22.5 °).
Therefore, in the present embodiment, 70 ° (> 22.5 ° × 3 = 6)
7.5 °) Find the next bar from the advanced position. 4) Scan the image from an angle advanced 70 ° from the angle (θ _1S ) at which the second bar (B ₁ ) was found. Find the third bar (B ₂ ). Bar (B ₂ ) as in the case of B ₀
The average value (θ ₂ ) of the angle between the starting point and the ending point of, and the minimum value (r ₂ ) of the distance from the center are determined.

If there is a projection other than the code inside the bar code, the image processing is to scan the image radially from the set center at step 2 to start each of the three projections (bars). The average value of the angle between the point and the end point and the maximum value of the distance from the center are determined. FIG. 4 is a diagram showing this stage, which is performed in the following procedure. 1) center was set in the center of the screen _C T _(x T, it scans the image in the counterclockwise direction radially from _{y T).} Set the concentric _R 1, _{R 2} centered on C _T, the portion between the _{R 1} and _{R 2} and the scan region. If there are protrusions other than the code inside the barcode, make the outer circumference of the scanning area larger than the outer circumference of the barcode, and make the inner circumference of the scanning area larger than the inner circumference of the barcode so as not to be affected by anything other than the code. Also increase. Then, image data (bright and dark) is read from the outer peripheral side to the inner peripheral side on the scanning line.

2) The average value of the angles is obtained as shown in FIG.
This is the same as when finding the minimum value. However, within the scanning area
The circumference is larger than the inner circumference of the barcode, so
The end point is a point where the inner circumference of the scanning area crosses the bar. Perimeter
Image data is read from the
When changing from light to dark, the number of bright pixels up to that point is R₂Or
What is subtracted is the distance from the center to the bar. Therefore,
θ ′_0SFrom θ '_0EThe number of bright pixels
R is the minimum value ₂Minus the maximum distance from the center
(R '₀).

Next, in the image processing, as step 3, 3
The center of a circle passing through three points consisting of the average value of the angles of the individual projections (bars) and the minimum or maximum distance is calculated and obtained. 5 to 7 are diagrams showing this stage, and are performed in the following procedure. _{1) B 0, B 1,} 3 point _{B 2} is as shown in FIG. 5 in polar coordinates with respect to the center _{C T} set. 2) Three points B ₀ , B ₁ , and B ₂ are defined as x = r · cos θ +
x _T, by _{y = -r · sinθ + y T} , as shown in FIG. 6 that substitution in the orthogonal coordinates of the screen. That is, B ₀
Is P ₀ (x ₀ , y ₀ ), B ₁ is P ₁ (x ₁ , y ₁ ), B _1
2 is replaced by P ₂ (x ₂ , y ₂ ), respectively.

3) In FIG. 7A, a straight line P₀P
₁And y = a₁x + b₁Then the vertical bisector is y =
(-1 / a₁) X + m₁Becomes Straight line P₁P₂And y =
a₂x + b₂Then the vertical bisector is y = (− 1 / a
₂) X + m₂Becomes a, b, m are P₀, P ₁, P₂of
It is a numerical value obtained from coordinates. Intersection of two perpendicular bisectors
But the desired center C_C(X_C, Y_C). FIG.
As shown in (b), y₀And y₁Is very small
, That is, the straight line P₀P₁When the gradient of is extremely small
Is a straight line because the gradient of the perpendicular bisector is very large.
P₀P₁Instead of a straight line P₀P₂Is used. FIG. 7 (c)
As shown in₁And y₂Is very small
Is a straight line P₁P₂Instead of a straight line P₀P₂Is used.

Next, in the image processing, as step 4, the image is scanned radially from the center obtained in step 3, and the average value of the angle between the starting point and the ending point of one protrusion (bar) is obtained. An array is obtained by searching for the presence or absence of a bar for each specified angle with the average value of the obtained angles as a starting point, and a mold number is specified from the obtained array. 8 to 10 show this stage, and are performed in the following procedure. 1) An image is scanned in a counterclockwise direction radially from the obtained center C _C (x _C , y _C ). The scan area, the read direction of the image data on the scan line, and the average value of the angle between the start point and the end point of the bar are the same as when the image is scanned from the set center.

2) Scan the image to find the first bar. Average value of the angle of one bar found first ( θ ₀ )
And the presence or absence of a bar is searched every 22.5 ° starting from θ ₀ . Since the barcode of this embodiment is divided into 16, the specified angle is 360 ° / 16 = 22.5 °. In the eight division, the presence or absence of a bar is searched every 45 °. In order to search for the presence or absence of a bar, several scanning lines before and after each angle are read and the presence or absence of reading is surely known. In FIG. 9, the arrangement of the bars is 1000 1110 1011 0000. In FIG. 10, the arrangement of the bars is 1011 0000 1000 1110. 9 and 10 have the same mold number.

3) The same mold number (10
It is 152) in hexadecimal notation, and only the arrangement of the bars differs depending on the read position. When arranged from the start bar, it becomes 1000 1110 1011 0000. All of the 16 arrangements in which this arrangement is a circular permutation have the same mold number (152 in decimal). 16 above
A conversion table called a look-up table (abbreviated as LUT) that outputs 152 when any of the arrays is input is provided in the storage device, and the mold number is specified from the obtained array.

[0020]

As described above, according to the present invention,
Since the center position of the code is directly calculated and obtained from the position data of the image of the projection indicating the code, it is not affected by the image of the projection other than the code. In addition, since the indexing accuracy of the center position is improved, the reading rate of the mold number is also improved.

[Brief description of the drawings]

FIG. 1 is a schematic front view showing a configuration of an apparatus for performing a mold number reading method of the present invention.

FIG. 2 is a diagram illustrating an example of a barcode, and illustrates a binary image obtained by binarizing an image obtained by an imaging device into bright and dark by an image processing device.

FIG. 3 is a diagram for scanning an image radially from a set center;
It is a figure which shows the method of calculating | requiring the average value of the angle of the start point and the end point of each protrusion (bar), and the minimum value of the distance from the center.

FIG. 4 is a diagram for scanning an image radially from a set center;
It is a figure which shows the method of calculating | requiring the average value of the angle of the start point and the end point of each protrusion (bar), and the maximum value of the distance from a center.

FIG. 5 is a diagram showing a method of calculating and calculating the center of a circle passing through three points consisting of an average value of angles of three projections (bars) and a minimum value or a maximum value of a distance.

FIG. 6 is a diagram showing a method of calculating and calculating the center of a circle passing through three points consisting of an average value of angles of three projections (bars) and a minimum value or a maximum value of a distance.

FIG. 7 is a diagram showing a method of calculating and calculating the center of a circle passing through three points consisting of an average value of angles of three projections (bars) and a minimum value or a maximum value of a distance.

FIG. 8 scans an image radially from the obtained center, finds the average value of the angle between the start point and the end point of one protrusion (bar), and uses the average value of the found angle as the starting point to specify the angle. It is a figure which shows the method of searching for the presence or absence of a bar | burr every time, and calculating | requiring an arrangement | sequence, and specifying a mold number from the calculated | required arrangement | sequence.

FIG. 9 scans an image radially from the obtained center, finds the average value of the angle between the start point and the end point of one protrusion (bar), and designates the angle specified using the average value of the found angles as the starting point. It is a figure which shows the method of searching for the presence or absence of a bar | burr every time, and calculating | requiring an arrangement | sequence, and specifying a mold number from the calculated | required arrangement | sequence.

FIG. 10 scans an image radially from the determined center to obtain 1
The average value of the angle between the starting point and the ending point of each of the protrusions (bars) is obtained, and the array is obtained by searching for the presence or absence of a bar at each specified angle with the obtained average value of the starting point as a starting point. It is a figure showing the method of specifying a model number.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass bottle 2 Bottle bottom 3 Lighting 4 Fresnel lens 5 Imaging device 6 Image processing device

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takanori Hazuki 1-17-1 Raw Mugi, Tsurumi-ku, Yokohama-shi, Kanagawa F-term in Kirin Techno System Co., Ltd. 5B072 BB00 CC17 CC24 CC26 HH20

Claims (1)

[Claims] 1. A method for reading a mold number indicated by a code composed of a plurality of protrusions circumferentially arranged on a bottle bottom, the method comprising photographing the bottle bottom and processing an obtained image. In the mold number reading method of reading the mold number, the image processing scans the image radially from the set center, and averages the angles of the start point and the end point of each of the three protrusions, and the distance from the center. Find the minimum or maximum value of the distance, calculate and calculate the center of a circle passing through three points consisting of the average value of the obtained angle and the minimum or maximum value of the distance, and scan the image radially from the obtained center. The average value of the angle between the start point and the end point of one projection is determined, and the array is determined by searching for the presence or absence of a projection at each specified angle with the average value of the determined angle as the starting point. A mold number reading method characterized by specifying a mold number.