JP3440261B2 - How to read the container number of the high pressure gas container - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for reading a container number of a high-pressure gas container, and more particularly to an optical character reading means for reading alphabetic characters and numerals constituting the container number. The present invention relates to a method of individually taking figures as individual figures into XY orthogonal coordinates, then processing the figures by image processing, identifying them as alphabetic characters and numerals, and automatically reading the container number. 2. Description of the Related Art Conventionally, symbols displayed on the surface of various articles have been automatically read. For example, in reading a postal code, numbers displayed on a paper surface such as a postcard are individually secured as figures by optical character reading means such as a television camera, and then each figure is image-processed and recognized as a number. I have to. At this time, image processing from figures to figures is performed by
Some basic patterns are stored in advance for each of the numbers from 0 to 9, and the optically read figure is appropriately scaled up and down. If so, the process is repeated, and if not, each figure is identified as a number and recognized as a postal code. [0004] However, the container number of a normal high-pressure gas container is different from the postal code consisting of only numerals, and is different from the postal code consisting of letters A to Z (upper case) and numerals 0 to 9. It is displayed in combination. For this reason, in the case of the conventional reading method, the letter "I", the number "1", and the letter "O"
And figures "0", alphabet "S" and numeral "5", and alphabet "Z" and numeral "2" may be misidentified. Further, in the case of a lightweight high-pressure gas container made of a synthetic resin or the like, the container number is displayed not on the seal but on a sticker attached to the body of the container. Although it may be captured as a graphic by the method, in the case of a metal high-pressure gas container, since the container number is engraved on the shoulder of the high-pressure gas container, if it is captured as a graphic by a conventional planar imaging method Since the container number was distorted, comparison with the basic pattern itself could not be performed. For example, the container number of the high-pressure gas container is:
It is stamped so as to be at the same height as the shoulder of the container when placed upright, that is, at approximately the same latitude as the spherical surface forming the shoulder of the container. Therefore, as shown by an imaginary line in FIG.
When the container number 3 is photographed as shown in FIG. 2, as shown in FIG. For this reason, even if the distorted image data is processed by the conventional method, it cannot be identified because it does not match the basic pattern of the symbol stored in the reading device in advance. For this reason, even if the management of the high-pressure gas container is to be automated by automatically reading the container number of the high-pressure gas container at a gas filling factory or the like, the reading of the container number depends on the visual inspection of the operator. In addition, there is a disadvantage that productivity is reduced due to an operator's reading error, which is a burden on the operator. Accordingly, the present inventors have conducted intensive studies so that the container number of the high-pressure gas container can be automatically and reliably read. As a result, it was found that the container number of the high-pressure gas container was specified on the container in a specific arrangement, and the arrangement of the container number was determined to separate the alphabetic part and the numerical part of the container number. The container number can be read more reliably, and the container number displayed on the shoulder of the container is
It has been found that it is possible to identify the container number by taking an image from a specific direction and performing image processing with a specific method. That is, an object of the present invention is to provide a reading method capable of identifying a container number displayed on a shoulder portion of a high-pressure gas container with high probability. [0010] In order to achieve the above object, a method for reading a container number of a high-pressure gas container according to the present invention comprises the steps of reading a container number displayed on a shoulder of a high-pressure gas container. And the number, the approximate normal position of the spherical surface forming the shoulder
In ipecac in the X-Y orthogonal coordinates as a figure individually taken by put et optical character reading means, each of said graphic
Surround the circumscribed rectangle with straight lines parallel to the X and Y axes, respectively.
An arc that forms and approximates the curve that connects the centroids of each circumscribed rectangle
And the centroid of each circumscribed rectangle from the center point
Each figure so that the straight line connecting
Rotate around the center . Thereafter, the distance between the figures is measured, and the
A series of figures are divided into alphabetic and numeric
Release, and then use the basic pattern for each figure as letters or numbers.
It is characterized by comparison with turns . [Operation] As described above , the shoulder is stamped on the high-pressure gas container.
The container number given is the approximate normal position on the spherical surface that forms the shoulder
And take it in the XY rectangular coordinates,
The constituent symbols are secured as a group of figures arranged in a fan shape.
At this time, each figure is not in the upright state, but the distortion is almost
Not really. Next, each of the group of figures arranged in a fan shape is
And circumscribed by a straight line parallel to the Y axis to form a circumscribed rectangle.
If you connect the centroids of the circumscribed rectangles,
Are located on a curve that approximates an arc centered at
You . Therefore, in the arc approximate to the above curve,
The straight line connecting the center point and the centroid of each circumscribed rectangle is
Since these lines are erect lines of the figure, these straight lines are
Rotate each figure around its centroid so that it becomes a line
Then, each figure becomes an erect state . On the other hand, the alphanumeric characters constituting the container number
Displayed on the container in an array. Therefore, each letter, number
After securing individual figures, measure the distance between each figure.
By specifying the container number in English
Part and number part. Therefore, in the container number
There are figures similar to the letter "I" and the number "1".
However, the figure in the alphabet part is only the basic pattern of the alphabet,
Also, figures in the number part should be distinguished from only the basic pattern of numbers.
Since comparison and collation can be performed, figures can be accurately identified . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in further detail with reference to the drawings, in the case of reading a container number displayed on a shoulder of a high-pressure gas container. First, as shown by a solid line in FIG. 1, a container number 3 engraved at substantially the same latitude on a spherical portion forming a shoulder of the high-pressure gas container 1 is referred to as a television camera from a substantially normal direction of the spherical surface. 2, the image is displayed on the monitor television 4 as shown in FIG. It is preferable that the television camera 2 is set so that the center of the container number 3 is on the vertical center line of the screen. The high-pressure gas container 1 may be settled at a predetermined position, or may be moving while being transported by a cart or a belt conveyor. In the vicinity of the container number 3 of the high-pressure gas container 1,
Not only the alphanumeric characters constituting the container number 3 but also a symbol indicating the type of gas filled in the high-pressure gas container 1 is included (in the case of this embodiment, N ₂ indicating that the container is a nitrogen filling container). Is engraved). In addition, the part engraved with the container number 3 is painted in a color different from the color painted on the outer wall of the high-pressure gas container 1, so that not only the visual but also the television camera 2 is painted.
Can also be easily identified. As described above, the graphic group secured in the XY rectangular coordinates of the reading device 5 is processed in the following procedure and recognized as a symbol. First, since the symbols of the gas types other than the container number 3 do not need to be processed, they are eliminated by image processing using the vertical positional relationship, and only the container numbers 3 arranged in a fan shape are extracted. As shown in FIG. 4, the extracted graphic group of the container number 3 is engraved on the shoulder of the high-pressure gas container 1 and is arranged in a fan shape as shown in FIG. The symbols at both ends are more greatly inclined. Next, the figure of each symbol is represented by an X axis and a Y axis.
Surrounded by four straight lines X1, X2, Y1, Y2 parallel to the axis,
A circumscribed rectangle 11 is formed for each figure, and a centroid 12 of each circumscribed rectangle 11 is obtained. Next, when the centroids 12 of the respective figures are connected, a curve 13 is formed. The curve 13 can be approximated to a part (arc) of a circle centered on a certain point by the least square method. it can. Therefore, since the centroid 12 of each figure can be assumed to exist on the arc of the approximated circle, the center point 14 of the arc is obtained on the XY orthogonal coordinates. Then, the centroid 12 of each figure and the center point 14 are connected by a straight line 15, the intersection angle α between the straight line 15 and the Y axis is determined, and a straight line 15 connecting the centroid 12 and the center point 14 is obtained. Each figure is rotated about the centroid 12 by an angle α so as to be parallel to the Y axis. By this operation, each figure is shown in FIG.
(1), the symbol stored in the reader 5 in advance can be compared with some basic patterns, and individual figures can be recognized. As shown in FIG. 6, since the symbols at both ends of the figure taken from the horizontal direction in FIG. 2 are not only distorted but also distorted, as shown in FIG. It is difficult and cannot be recognized as a sign. After the individual figures are made recognizable as described above, the alphabetical part and the numeric part are separated by the procedure described below. It is possible to perform the following separation procedure in the inclined state shown in FIG. 4, but there is a type such as "I" or "1" in which the width dimension greatly differs between the erect state and the inclined state. The separation accuracy can be improved after the erect state shown in FIG. First, before explaining the procedure for separating the alphabetic part and the numeral part, the general arrangement of the container numbers in the high-pressure gas container will be described. First, the container numbers of the high-pressure gas containers are, as described above, alphabets (uppercase letters) of AZ and 0-9.
It is composed of a combination of Arabic numerals, but alphabets and numbers are not mixed at random, there is an alphabetic character on the left side of the symbol string that constitutes the container number, and a number on the right side . That is, the container number is in a state where a plurality of numbers are arranged after at least one alphabetic character. Next, an appropriate interval is provided between the alphabetic characters and the numbers, and the numbers are relatively close to each other. In addition, "-" (hyphen) may be inserted between numbers, and this hyphen is usually inserted between the second and third characters from the right. Further, when there are a plurality of alphabets, the interval between the alphabets is not constant, but even in such a case, the interval between the alphabets and the numbers becomes maximum. The hyphen may be left as it is until the state shown in FIG. 5, but when the circumscribed rectangle 11 is formed, an alphabetic character or a character is determined based on the interval between two straight lines X1 and X2 parallel to the X axis. It is preferable to exclude it because it is not a number. In other words, letters with almost no vertical height do not exist in alphabetic characters and numbers, so by excluding such characters, it is possible to exclude dirt on the container number part, etc. Speed can be improved. FIG. 7 shows an example of a procedure for separating an alphabetic part and a numeric part.
Shown in First, after removing the portion corresponding to the hyphen (step 101), as shown in FIGS. 8 to 11, the interval between the characters (graphics) (the character interval is set to S1,
S2, S3,..., Sn) (step 10).
2). Then, the obtained intervals are compared in step 103. If the leftmost interval S1 is not the maximum interval, in step 104 the largest interval is selected from each interval, and this maximum is selected. Let the character spacing point be the alphanumeric separation point S. That is, as shown in FIG. 8, when the second interval S2 is larger than the leftmost interval S1,
The second interval S2 is defined as a separation point S, each figure on the left side of the separation point S is compared with a basic pattern of an alphabet as an alphabetic part, and each figure on the right side of the separation point S is a numerical part as a numeric part. To match. When a hyphen is inserted,
As shown in FIG. 9, even if the interval S5 of the hyphen portion is the maximum interval, since it has already been excluded in step 101, the other intervals are compared with the maximum interval S3.
Becomes the alphanumeric separation point S. If it is determined in step 103 that the interval S1 is the maximum, it is determined in step 105 whether or not the second interval S2 is the second interval. The second interval S2 is defined as an alphanumeric separation point S (see FIG. 10). The interval S1 is the maximum and the second interval S
If 2 is not the second, the process proceeds to step 107, where the leftmost interval S1 is set as the alphanumeric separation point S (see FIG. 11). As described above, the alphanumeric separation points are determined according to the arrangement pattern unique to the container number of the high-pressure gas container, and the letters "I" and "I" are compared by comparing the alphabetic characters and numerals with the respective basic patterns. "1", "O" and "0", "S" and "5", and "Z" and "2" can be reliably identified. As a result, the symbol string imprinted on the shoulder of the high-pressure gas container 1 can be read as a container number unique to the container, and from the read container number, the manufacturing year of each container previously stored in the database can be obtained. By importing management data such as month, serial number, filling gas name, weight, and location,
The high-pressure gas container 1 can be managed. The container number of the high-pressure gas container is usually engraved on the shoulder, but when reading the engraved number on the body or the like, the processing shown in FIGS. 4 and 5 is performed. Instead, reading can be accurately performed only by performing the procedure shown in FIG. As described above, according to the method of the present invention, even if the container number of the high-pressure gas container is displayed in a mixture of alphabetic characters and numerals, the individual symbols constituting the container number are set in advance. Since it can be distinguished as alphabetic or numeric, when comparing figures with basic patterns, it is only necessary to compare the figures in the alphabet part with only the basic pattern of alphabets, and the figures in the number part with only the basic pattern of numbers. , The letter "I" and the number "1"
Even if there is a similar symbol in the alphabetic part and the symbol in the numeral part as in the case of, for example, it can be identified with high accuracy and can be read accurately. Even if the container number is displayed on the shoulder of the high-pressure gas container, the container number can be read automatically and accurately, so that the management of the high-pressure gas container can be performed reliably and easily. This can greatly reduce the burden on the operator and improve the productivity.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram showing a state in which a container number stamped on a shoulder of a high-pressure gas container is photographed by a television camera. FIG. 2 is a diagram showing a state of a container number when photographing from a horizontal direction of a high-pressure gas container. FIG. 3 is a diagram showing a state of a container number when photographing from a normal direction of a spherical surface of a shoulder of a high-pressure gas container. FIG. 4 is an explanatory diagram of a procedure for processing graphic data by the method of the present invention. FIG. 5 is a diagram showing a state of graphic data after processing by the method of the present invention. FIG. 6 is a diagram showing a state after graphic data taken from a horizontal direction is processed in the same procedure as the method of the present invention. FIG. 7 is a flowchart illustrating an example of a procedure for separating an alphabetic part and a numeric part. FIG. 8 is an explanatory diagram showing an example of an alphanumeric separation point. FIG. 9 is an explanatory diagram showing another example of an alphanumeric separation point. FIG. 10 is an explanatory diagram showing still another example of an alphanumeric separation point. FIG. 11 is an explanatory diagram showing still another example of an alphanumeric separation point. [Description of Signs] 1 ... High-pressure gas container, 2 ... TV camera, 3 ... Container number,
11: circumscribed rectangle, 12: centroid of circumscribed rectangle, 13: curve, 14: center point, 15: straight line, S: alphanumeric separation point, S
1, S2, S3 ... character spacing

Continuation of the front page (72) Inventor Yoshimi Oda 4-62-22 Kannonshinmachi, Nishi-ku, Hiroshima-shi, Hiroshima Inside Mitsubishi Heavy Industries, Ltd. (56) References JP-A-57-101986 (JP, A) JP-A-64- 1089 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G06K 9/00-9/76

Claims (1)

(57) [Claims 1] An alphabet and a numeral constituting a container number displayed on a shoulder of a high-pressure gas container are converted into a spherical surface forming the shoulder.
Are taken by the optical character reading means from the approximate normal line position and individually taken into the XY rectangular coordinates as a figure ,
Surround the figure with straight lines parallel to the X and Y axes, respectively.
Form a tangent rectangle, close to the curve connecting the centroids of each circumscribed rectangle.
Find the center point of a similar arc, and from that center point,
Each figure so that the line connecting the centroids of the polygons is parallel to the Y axis
Is rotated around each centroid, the distance between each figure is measured, a series of figures are separated into alphabetic and numeric parts based on the relationship between the figures, A method for reading a container number of a high-pressure gas container, wherein the container number is compared with a basic pattern.