JPH07225813A - Read method for vessel number of high pressure gas vessel - Google Patents

Abstract

PURPOSE:To provide the read method which surely discriminates the vessel number displayed on a high pressure gas vessel. CONSTITUTION:Alphanumeric characters constituting a vessel number 3 are individually taken as graphic data, and respective graphic data are separated into an alphabet part and a numeric part based on the arrangement of alphanumeric characters peculiar to the vessel number 3, and graphic data of the alphabet part are compared and collated with fundamental patterns or alphabets, and those of the numeric part are compared and collated with fundamental patterns of figures, and each graphic data is discriminated as an alphabet or a figure. The vessel number 3 displayed on the shoulder part of a high pressure gas vessel 1 is photographed from an approximate normal position of the shoulder part, and its picture is taken into X-Y rectangular coordinates, and each graphic data is enclosed with lines parallel with X and Y axes to form a circumscribed rectangle 11. A center 14 of an arc approximating the curve which connects graphic centers 12 of respective circumscribed rectangles 11 is obtained, and each graphic data is so rotated that the line connecting the center 14 and the graphic center 12 is parallel with the Y axis, and thereafter, the alphabet part and the numeric part are separated and discriminated in the same manner.

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 the container number of a high-pressure gas container, and more specifically, the alphabetic characters and numbers constituting the container number are individually figured by optical character reading means as XY orthogonal coordinates. The present invention relates to a method for automatically reading a container number by image-processing each figure after identifying it as an alphabetic character or numeral, after taking it in.

[0002]

2. Description of the Related Art Conventionally, symbols displayed on the surface of various articles have been automatically read. For example, when reading a postal code, the numbers displayed on the paper surface of a postcard or the like are individually secured as figures by an optical character reading means such as a television camera, and then each figure is subjected to image processing to be recognized as numbers. I have to.

Image processing from figures to numbers at this time is as follows.
Some basic patterns are stored in advance for each number from 0 to 9, and the optically read graphic is appropriately enlarged or reduced, and the basic pattern is compared and collated by, for example, an overlay method or the like to find a match. If so, the answer is used, and if they do not match, the process of eliminating them is repeated to identify each figure as a numeral and recognize it as a postal code.

[0004]

However, the container number of an ordinary high-pressure gas container is different from the above-mentioned zip code consisting of only numbers, and is a combination of alphabetic characters (capital letters) of A to Z and numbers of 0 to 9. It is displayed. Therefore, in the case of the conventional reading method, the letter "I", the number "1", and the letter "O"
In some cases, figures with similar shapes such as the number "0", the letter "S" and the number "5", and the letter "Z" and the number "2" were mistakenly recognized.

Furthermore, in the case of a lightweight high-pressure gas container made of synthetic resin or the like, the container number is displayed not on the engraved mark but on the sticker attached to the body of the container. Although it may be captured as a figure by the method, in the case of a metal high-pressure gas container, the container number is stamped on the shoulder of the high-pressure gas container, so if it is captured as a figure by the conventional planar imaging method. Since the container number is distorted, it was not possible to compare and collate with the basic pattern.

For example, the container number of the high pressure gas container is
It is engraved so as to be at the same height of the shoulder portion of the container when placed upright, that is, at approximately the same latitude of the spherical surface forming the shoulder portion of the container. Therefore, as shown by the phantom line in FIG. 1, the television camera 2 is viewed from the horizontal direction of the high-pressure gas container 1 placed upright.
When the container number 3 is photographed with, the characters on both ends are greatly tilted and distorted due to the influence of the spherical surface, as shown in FIG. Therefore, 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 an attempt is made to automatically read the container number of the high-pressure gas container in a gas filling factory or the like to automate the management of the high-pressure gas container, the reading of the container number depends on the operator's visual inspection. However, there is an inconvenience that productivity is reduced due to a mistake in reading by the worker, which is a burden on the worker.

Therefore, the inventors of the present invention have conducted extensive studies so that the container number of the high-pressure gas container can be automatically and surely read. As a result, it was found that the container number of the high-pressure gas container was clearly indicated on the container in a certain specific arrangement, and by distinguishing the arrangement state of the container number, the letter part and the number part of the container number were separated. The container number can be read more reliably, and the container number displayed on the shoulder of the container is
It was found that it is possible to identify the container number by performing image processing by a specific method after photographing from a specific direction.

That is, an object of the present invention is to provide a reading method capable of identifying a container number of a high pressure gas container with high probability.

[0010]

In order to achieve the above object, the method of reading the container number of a high pressure gas container according to the present invention is an optical system in which the letters and numbers constituting the container number displayed on the high pressure gas container are After the individual figures are individually taken into the XY Cartesian coordinate by means of the dynamic character reading means, the intervals between the figures are measured, and a series of figures are separated into an alphabetic character part and a numerical part from the relationship of the mutual intervals. Next, each figure is compared with the basic pattern as an alphabetic character or a numerical value.

Further, when the container number is displayed on the shoulder of the high-pressure gas container, the container number is determined from the approximate normal line of the spherical surface forming the shoulder before measuring the distance between the figures. After photographing and individually capturing in the XY Cartesian coordinates as a figure, each figure is surrounded by straight lines parallel to the X axis and the Y axis to form a circumscribed quadrangle, and the centroid of each circumscribed quadrangle is defined. A feature is that a center point of an arc approximate to a connecting curve is obtained, and each figure is rotated about each centroid so that a straight line connecting the centroids of individual circumscribing rectangles from the center point is parallel to the Y axis. And

[0012]

[Operation] As described above, the alphanumeric characters that make up the container number are displayed on the container in a specific arrangement. Therefore, the container number can be separated into an alphabetic part and a numerical part based on the mutual relation of the intervals by measuring the distance between the respective figures after securing each letter and number individually as a figure. Therefore, even if there are similar figures such as the letter "I" and the number "1" in the container number, the figure of the alphabet part is only the basic pattern of the alphabet and the figure of the numeral part is the numeral pattern. Since it is possible to compare and collate by sharply distinguishing from only the basic pattern, the figure can be accurately identified.

The container number stamped on the shoulder portion of the high-pressure gas container constitutes the container number when photographed from a position approximately normal to the spherical surface forming the shoulder portion and taken into the XY orthogonal coordinates. The symbols to be reserved are secured as a group of figures arranged in a fan shape. At this time, each figure is not in an upright state, but there is almost no distortion. Next, circumscribing quadrangles are formed by enclosing each fan-shaped figure group with straight lines parallel to the X-axis and the Y-axis, and connecting the centroids of the circumscribed quadrilaterals obtained, the connected lines are , Is located on a curve that approximates an arc centered at a certain point.

Therefore, since the straight line connecting the center point of the arc approximated to the above curve and the centroid of each circumscribing quadrangle is the upright line of each figure, these straight lines are parallel to the Y axis. As described above, when each figure is rotated around the centroid, each figure becomes upright and it is possible to collate with the basic pattern. After that, as described above, the series of figures can be accurately identified by separating the series of figures into the alphabet part and the number part from the space between the figures.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described in more detail with reference to the drawings in the case of reading the container number displayed on the shoulder of a high-pressure gas container.

First, as shown by the solid line in FIG. 1, a container number 3 is stamped at approximately the same latitude on the spherical portion forming the shoulder of the high-pressure gas container 1 from a direction substantially normal to the spherical surface of the television camera. The image is photographed by 2, and the image is displayed on the monitor television 4 as shown in FIG.

The television camera 2 is preferably set so that the central portion of the container number 3 is on the center line in the vertical direction of the screen. Further, the high-pressure gas container 1 may be left stationary at a predetermined position, or may be moving while being conveyed by a carriage or a belt conveyor.

In the vicinity of container number 3 of the high pressure gas container 1,
Not only the alphanumeric characters that make up the container number 3, but also a symbol that represents the type of gas that is filled in the high-pressure gas container 1 (in the case of this embodiment, N ₂ that indicates a nitrogen filling container is included). Is engraved). In addition, a color different from the color applied to the outer wall of the high-pressure gas container 1 is applied to the part where the container number 3 is engraved.
Can be easily identified by.

As described above, the graphic group secured in the XY orthogonal coordinates of the reading device 5 is processed in the following procedure and is 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 utilizing the upper and lower positional relationship by image processing, and only the container numbers 3 arranged in a fan shape are extracted.

As described above, the extracted graphic group of the container number 3 has a symbol string in a fan-shaped state as shown in FIG. 4 because of the marking on the shoulder portion of the high-pressure gas container 1 as described above. The symbols at both ends are more inclined.

Next, the graphic of each symbol is represented by X-axis and Y-axis.
Enclose with four straight lines X1, X2, Y1, Y2 parallel to the axis,
A circumscribed quadrangle 11 is formed for each figure, and a centroid 12 of each circumscribed quadrangle 11 is obtained.

Next, the centroids 12 of the respective figures are connected to form a curve 13. This curve 13 can be approximated to a part (circle) of a circle centered on a certain point by the method of least squares. it can. Therefore, it can be assumed that the centroid 12 of each figure exists on the arc of the approximated circle, and the center point 14 of the arc is obtained on the XY orthogonal coordinates.

Then, the centroid 12 and the center point 14 of each figure are connected by a straight line 15, the crossing 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, the respective figures are shown in FIG.
Since the upright state as shown in (1) is established, it becomes possible to collate some basic patterns of symbols stored in the reading device 5 in advance, and individual figures can be recognized.

Note that, in the figure photographed from the horizontal direction in FIG. 2, the symbols at both ends are not only inclined but also distorted as shown in FIG. It is difficult and cannot be recognized as a symbol.

After the individual figures are made recognizable as described above, the alphabet portion and the numeral portion are separated by the procedure described below. Although it is possible to perform the following separation procedure in the tilted state shown in FIG. 4, there are some cases such as “I” and “1” in which the width dimension is significantly different between the upright state and the tilted state, The separation accuracy can be improved after the upright state shown in FIG.

First, before explaining the procedure for separating the alphabetic part and the numeric part, the general arrangement of container numbers in the high-pressure gas container will be described. First, the container number of the high-pressure gas container is, as described above, the alphabetical characters (capital letters) of AZ and 0-9.
It consists of a combination of Arabic numerals and numbers, but the letters and numbers do not coexist randomly, and there are letters on the left side of the symbol string that constitutes the container number and numbers on the right side. . That is, the container number is in a state in which a plurality of numbers are arranged after at least one alphabetic character.

Next, an appropriate gap is provided between the letters and the numbers so that the numbers are relatively close to each other. A "-" (hyphen) may be inserted between the numbers, but this hyphen is usually inserted between the second and third characters from the right. Furthermore, when there are multiple letters, the spacing between the letters is not constant, but even in that case, the spacing between the letters and the numbers is maximum.

The hyphen may be left as it is until the state of FIG. 5, but when the circumscribing quadrangle 11 is formed, the hyphen is separated from the distance between the two straight lines X1 and X2 parallel to the X axis by an alphabetic character or It is preferable to judge that it is not a number and exclude it. That is, letters with almost no height in the vertical direction do not exist in letters and numbers, so by excluding such letters, stains on the container number part can also be eliminated, and the accuracy of reading operation and The speed can be improved.

FIG. 7 shows an example of a procedure for separating the alphabet part and the number part.
Shown in. First, after excluding the portion corresponding to the hyphen (step 101), as shown in FIGS. 8 to 11, the interval between the characters (graphics) (the character interval from the left to S1,
(S2, S3, ..., Sn) are obtained (step 10)
2).

Then, the obtained intervals are compared in step 103. If the leftmost interval S1 is not the maximum interval, the maximum interval is selected in step 104, and the maximum interval is selected. The character spacing point is an alphanumeric separation point S.

That is, as shown in FIG. 8, when the second space S2 is larger than the leftmost space S1,
The second space S2 is used as a separation point S, each figure on the left side of the separation point S is used as an alphabetic part to be compared with the basic pattern of the alphabet, and each figure on the right side of the separation point S is used as a numeral part to be a basic pattern of numbers. To match.

If a hyphen is inserted,
As shown in FIG. 9, even if the interval S5 of the hyphen part is the maximum interval, it is already excluded in step 101, so the other intervals are compared and the maximum interval S3 is obtained.
Is the alphanumeric separation point S.

When it is determined in step 103 that the interval S1 is the maximum, it is determined in step 105 whether the second interval S2 is the second interval. The second space S2 is the alphanumeric separation point S (see FIG. 10).

The interval S1 is maximum and the second interval S is
When 2 is not the second, the process proceeds to step 107 and the leftmost space S1 is set as the alphanumeric character separation point S (see FIG. 11).

In this way, the alphanumeric separation points are obtained according to the arrangement pattern unique to the container number of the high-pressure gas container, and the letters and numbers are compared with their respective basic patterns to obtain the above-mentioned "I" and " 1 "," O "and" 0 "," S "and" 5 ", and" Z "and" 2 "can be reliably identified.

As a result, the symbol string engraved on the shoulder portion of the high-pressure gas container 1 can be read as the container number unique to the container, and the manufacturing year of each container stored in the database in advance from the read container number. By importing management data such as month, serial number, filling gas name, weight, 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 part on the body or the like, the processes shown in FIGS. 4 and 5 are performed. Instead, the reading can be performed with high accuracy only by performing the procedure shown in FIG. 7.

[0039]

As described above, according to the method of the present invention, even if the container number of the high-pressure gas container is displayed as a mixture of letters and numbers, the individual symbols constituting the container number are preliminarily letters or numbers. Therefore, when comparing the figure with the basic pattern, the figure in the alphabet part only needs to be compared with the basic pattern of letters, and the figure in the number part with the basic pattern of numbers only. "I" and the number "1"
Even if the symbols in the alphabet and the symbols in the numbers have similar shapes, such as, it is possible to identify them with high accuracy and read them 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 is reliable and easy. Therefore, the burden on the operator can be significantly reduced, and the productivity can be improved.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a state in which a container number engraved on a shoulder portion of a high-pressure gas container is photographed by a television camera.

FIG. 2 is a diagram showing a state of container numbers when the high-pressure gas container is photographed from the horizontal direction.

FIG. 3 is a diagram showing a state of container numbers when images are taken from a direction normal to a spherical surface of a shoulder portion 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 being processed by the method of the present invention.

FIG. 6 is a diagram showing a state after the graphic data photographed from the horizontal direction is processed in the same procedure as the method of the present invention.

FIG. 7 is a flowchart showing an example of a procedure for separating an alphabet part and a number part.

FIG. 8 is an explanatory diagram showing an example of alphanumeric character separation points.

FIG. 9 is an explanatory diagram showing another example of alphanumeric separation points.

FIG. 10 is an explanatory diagram showing still another example of alphanumeric separation points.

FIG. 11 is an explanatory diagram showing still another example of alphanumeric separation points.

[Explanation of symbols]

1 ... High-pressure gas container, 2 ... TV camera, 3 ... Container number,
11 ... circumscribed quadrangle, 12 ... centroid of circumscribed quadrangle, 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 Junichiro Sugakata 4-320 Tsukagoshi, Sachi-ku, Kawasaki-shi, Kanagawa Nihon Oxido Co., Ltd. (72) Yoshimi Oda, 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima-shi, Hiroshima Issue Mitsubishi Heavy Industries Ltd.

Claims (2)

[Claims] 1. An alphabetic character and a numeral constituting a container number displayed on a high-pressure gas container are individually incorporated as a figure into XY Cartesian coordinates by an optical character reading means, and then the intervals between the figures are mutually separated. The container number of the high-pressure gas container is characterized by separating a series of figures into alphabetic and numeric parts based on the relationship of mutual intervals, and then comparing and contrasting each figure with alphabetic or numerical figures with the basic pattern. How to read. 2. When the container number is displayed on the shoulder of the high pressure gas container, before measuring the distance between the figures,
The container number is photographed from a position approximately normal to the spherical surface forming the shoulder portion and individually captured as a figure in the XY orthogonal coordinates, and then each figure is a straight line parallel to the X axis and the Y axis. Form a circumscribed quadrangle by enclosing with, and find the center point of the arc that approximates the curve connecting the centroids of each circumscribed quadrangle, and make the straight line connecting the centroids of each circumscribed quadrangle parallel to the Y-axis. The method for reading the container number of a high-pressure gas container according to claim 1, wherein each figure is rotated around each centroid.