JP7651045B2 - Pipe symbol reading device and pipe symbol reading method - Google Patents

Description

The present invention relates to a pipe symbol reading device and a pipe symbol reading method that read a rugged symbol formed on the outer surface of a pipe by recesses or protrusions aligned in one circumferential direction.

For example, in cast iron pipes (one example of a water pipe) used for water supply, symbols including letters, figures, etc. are formed in an uneven pattern of recesses or protrusions on the end face or flange face of the pipe. The symbols indicate predetermined pipe type, nominal diameter, manufacturing plant, manufacturing year, lot number, manufacturer, individual pipe identification number, etc.

As described above, character reading devices are known that read characters formed in an uneven manner on the flange surface. For example, Patent Document 1 discloses a character reading device that reads characters formed by unevenness by rotating a tube in a fixed direction around its axis, measuring the tube surface using a light-cutting method, and acquiring a two-dimensional processed image from profile data of the height of the unevenness on the measured tube surface. This makes it possible to read characters formed by the unevenness, which would be difficult to read using a CCD camera or the like due to reflected light.

Patent No. 6415164

The character reading device disclosed in Patent Document 1 continues to acquire the profile data for one revolution of the end face of the tube, and ends acquiring the profile data when a blank area whose circumferential length is equal to or greater than a predetermined width is detected. Therefore, the character reading device disclosed in Patent Document 1 needs to identify the blank area in order to end acquisition of the profile data and identify characters (relief symbols) formed by recesses and projections.

However, for example, if the nominal diameter of the pipe is relatively small and the embossed symbols are densely formed around the entire circumference of the end face of the pipe, or if the embossed symbols are evenly spaced around the entire circumference of the end face of the pipe, the circumferential length of the blank area may be less than the specified width. In this case, the character reading device disclosed in Patent Document 1 may not be able to identify the blank area. As a result, when the profile data is obtained using the character reading device disclosed in Patent Document 1, the end point of data acquisition may be unclear.

As described above, if the blank area cannot be identified on the outer surface of the pipe, data acquisition may continue unnecessarily, lengthening the time it takes to read the uneven symbol, or profile data of the uneven symbol formed on the end face of the pipe may not be obtained with high accuracy.

Therefore, it is desirable for a symbol reading device for reading the embossed symbols formed on the outer surface of a pipe to be able to read the embossed symbols more accurately and in a shorter time.

The object of the present invention is to provide a pipe symbol reading device and a pipe symbol reading method that can read the embossed symbol formed on the outer surface of a pipe with high accuracy and reduce the time required to read the embossed symbol.

The pipe symbol reading device according to one embodiment of the present invention is a symbol reading device that reads a rugged symbol formed by recesses or protrusions arranged in one circumferential direction on the outer surface of a pipe. This device has a three-dimensional data acquisition unit that acquires three-dimensional data of the rugged symbol by measuring the height of the rugged symbol relative to the outer surface of the pipe while rotating the pipe relatively around its axis, an image data conversion unit that converts the acquired three-dimensional data into image data in which the rugged symbols are arranged in a straight line, a reference symbol identification unit that identifies a reference symbol in the image data that serves as a reference for starting to read the rugged symbol, and a symbol reading unit that uses the image data to read the rugged symbol based on the reference symbol (first configuration).

According to the above-mentioned configuration, the three-dimensional data of the embossed symbols arranged in the circumferential direction on the outer peripheral surface of the pipe is acquired by the three-dimensional data acquisition unit, and image data in which the embossed symbols are arranged in a straight line can be obtained from the three-dimensional data. Then, by identifying a reference symbol in the image data that serves as a reference for starting to read the embossed symbols, the embossed symbols can be read using the reference symbol as a reference.

This allows the embossed symbol to be read using the reference symbol as a reference, so that the embossed symbol can be read more accurately from the image data. Moreover, even if the blank area disclosed in Patent Document 1 cannot be identified, by identifying the reference symbol in the image data converted from the three-dimensional data, acquisition of the three-dimensional data is not continued. Therefore, the reading time for the embossed symbol is not unnecessarily extended, and the embossed symbol can be read in a shorter time.

Therefore, a symbol reading device having the above-mentioned configuration can read the embossed symbols formed on the outer surface of a pipe with greater accuracy and can shorten the time required to read the embossed symbols.

In the first configuration, the three-dimensional data acquisition unit acquires three-dimensional data of the uneven symbols while rotating the tube relatively in the opposite direction to the one direction in which the uneven symbols are arranged (second configuration).

This allows the three-dimensional data acquisition unit to acquire three-dimensional data of the embossed symbols in one direction, which is the arrangement direction of the embossed symbols. This allows the embossed symbols to be read more quickly and reliably.

In the first configuration, the symbol reading unit uses the image data to read the embossed symbol located behind the reference symbol in the one direction, which is the arrangement direction of the embossed symbols (third configuration).

This allows the symbol reading unit to use image data to read the embossed symbol that is located behind the reference symbol in one direction, which is the arrangement direction of the embossed symbols. This allows the embossed symbol to be read more reliably.

In the first configuration, the three-dimensional data acquisition unit acquires three-dimensional data of the embossed symbol while rotating the pipe one or more times relative to the axis. The symbol reading unit uses the image data to read the embossed symbol located at a predetermined position in the opposite direction to the one direction in which the embossed symbols are arranged relative to the reference symbol (fourth configuration).

As a result, even if the reference symbol is erroneously determined to be another symbol in the image data obtained from the three-dimensional data acquired while the tube is rotating one or more times around its axis, the embossed symbol can be read more reliably by reading the embossed symbol located at a predetermined position in the opposite direction to the one direction in which the embossed symbols are arranged relative to the reference symbol subsequently identified by the reference symbol identification unit.

In the first configuration, the three-dimensional data acquisition unit divides the three-dimensional data into a predetermined data length and outputs the divided three-dimensional data. The image data conversion unit concatenates a plurality of the divided three-dimensional data and converts the data into the image data (fifth configuration).

This allows the volume of data output from the three-dimensional data acquisition unit to be reduced, thereby reducing the load on the symbol reading device.

In the first configuration, the symbol reading unit has a data extraction unit that extracts a predetermined range of image data from the image data at a predetermined position in the arrangement direction of the embossed symbol from the reference symbol, and a reading execution unit that reads the embossed symbol using the image data of the range extracted by the data extraction unit (sixth configuration).

This allows the size of the image data required to read embossed symbols to be reduced. This reduces the load on the symbol reading device when reading embossed symbols from image data.

Moreover, since image data of a specified range in which the embossed symbols are to be read can be extracted from the image data, it is possible to prevent the erroneous reading of image data outside the specified range. Therefore, the embossed symbols to be read from the image data can be read with greater accuracy.

In the first configuration, the pipe symbol reading device further includes an image data filter unit that removes specific symbol data from the image data and generates image data for reading the embossed symbol by the symbol reading unit (seventh configuration).

This allows certain symbol data to be removed from the image data and the embossed symbols to be read. Therefore, only the necessary symbols can be read with high accuracy in the image data. This allows the embossed symbols formed on the outer surface of the pipe to be read with high accuracy.

In the first configuration, the three-dimensional data acquisition unit acquires three-dimensional data in which the inner wall and the outer wall of the pipe each form the contour of the area in which the embossed symbol is read. The image data conversion unit converts the contour in the image data into a straight line portion that can distinguish between the area and the outside of the area (eighth configuration).

This makes it possible to clearly distinguish between the embossed symbol and the contour in the image data. Therefore, when reading the embossed symbol using the image data, it is possible to prevent the contour from being mistakenly read as part of the embossed symbol. This makes it possible to read the embossed symbol with greater accuracy.

The pipe symbol reading method according to one embodiment of the present invention is a symbol reading method for reading a rugged symbol formed by recesses or protrusions arranged in one circumferential direction on the outer surface of a pipe. This method includes a three-dimensional data acquisition step for acquiring three-dimensional data of the rugged symbol by measuring the height of the rugged symbol relative to the outer surface of the pipe while rotating the pipe relatively around its axis, an image data conversion step for converting the three-dimensional data acquired in the three-dimensional data acquisition step into image data in which the rugged symbols are arranged in a straight line, a reference symbol identification step for identifying a reference symbol that serves as a reference for starting to read the rugged symbol in the image data converted in the image data conversion step, and a symbol reading step for reading the rugged symbol using the image data as a reference for the reference symbol identified in the reference symbol identification step (first method).

According to the above-mentioned method, three-dimensional data of the embossed symbols arranged in the circumferential direction on the outer peripheral surface of the pipe is acquired in a three-dimensional data acquisition step, and image data in which the embossed symbols are arranged in a straight line can be obtained from the three-dimensional data. Then, by identifying a reference symbol in the image data that serves as a reference for starting to read the embossed symbols, the embossed symbols can be read using the reference symbol as a reference.

This allows the embossed symbol to be read using the reference symbol as a reference, so that the embossed symbol can be read more accurately from the image data. Moreover, even if the blank area disclosed in Patent Document 1 cannot be identified, by identifying the reference symbol in the image data converted from the three-dimensional data, acquisition of the three-dimensional data is not continued. Therefore, the reading time for the embossed symbol is not unnecessarily extended, and the embossed symbol can be read in a shorter time.

Therefore, the above-mentioned symbol reading method can read the embossed symbols formed on the outer surface of the pipe with greater accuracy and can shorten the time required to read the embossed symbols.

In the first method, the pipe symbol reading method further includes a divided three-dimensional data generation step of dividing the three-dimensional data acquired in the three-dimensional data acquisition step into a predetermined length to generate divided three-dimensional data. The image data conversion step connects a plurality of the divided three-dimensional data generated in the divided three-dimensional data generation step to convert the data into the image data (second method).

This allows the amount of data output from the acquisition unit in the three-dimensional data acquisition step to be reduced, thereby reducing the load on the device when reading symbols.

In the first method, the symbol reading step includes a data extraction step of extracting a predetermined range of image data from the image data obtained in the image data conversion step at a predetermined position from the reference symbol in the arrangement direction of the embossed symbol, and a reading execution step of reading the embossed symbol using the image data of the range extracted in the data extraction step (third method).

This allows the size of the image data required to read embossed symbols to be reduced. This reduces the load on the device when reading embossed symbols from image data.

Moreover, since image data of a specified range in which the embossed symbols are to be read can be extracted from the image data, it is possible to prevent the erroneous reading of image data outside the specified range. Therefore, the embossed symbols to be read from the image data can be read with greater accuracy.

In the first method, in the three-dimensional data acquisition step, three-dimensional data is acquired in which the inner and outer walls of the pipe each form the contour of the area in which the embossed symbol is read. In the image data conversion step, the contour in the image data is converted into a straight line portion that can distinguish between the area and the outside of the area (fourth method).

This makes it possible to clearly distinguish between the embossed symbol and the contour in the image data. Therefore, when reading the embossed symbol using the image data, it is possible to prevent the contour from being mistakenly read as part of the embossed symbol. This allows the embossed symbol to be read with greater accuracy.

A pipe symbol reading device according to one embodiment of the present invention has a three-dimensional data acquisition unit that acquires three-dimensional data of the embossed symbol by measuring the height of the embossed symbol relative to the outer surface of the pipe while rotating the pipe relatively around its axis, an image data conversion unit that converts the acquired three-dimensional data into image data in which the embossed symbol is arranged in a straight line, a reference symbol identification unit that identifies a reference symbol in the image data that serves as a reference for starting to read the embossed symbol, and a symbol reading unit that uses the image data to read the embossed symbol based on the reference symbol.

A pipe symbol reading method according to one embodiment of the present invention includes a three-dimensional data acquisition step of acquiring three-dimensional data of the embossed symbol by measuring the height of the embossed symbol relative to the outer surface of the pipe while rotating the pipe relatively around its axis; an image data conversion step of converting the three-dimensional data acquired in the three-dimensional data acquisition step into image data in which the embossed symbols are arranged in a straight line; a reference symbol identification step of identifying a reference symbol that serves as a reference for starting to read the embossed symbol in the image data converted in the image data conversion step; and a symbol reading step of reading the embossed symbol using the image data as a reference for the reference symbol identified in the reference symbol identification step.

This allows the embossed symbol to be read more accurately by identifying a reference symbol in the image data that serves as a reference for starting to read the embossed symbol, and reading the embossed symbol using the reference symbol as a reference. Furthermore, even if the blank area disclosed in Patent Document 1 cannot be identified, acquisition of the three-dimensional data is not continued. Therefore, the embossed symbol can be read in a shorter time without unnecessarily lengthening the reading time for the embossed symbol. Therefore, the embossed symbol formed on the outer surface of the pipe can be read more accurately and the reading time for the embossed symbol can be shortened.

FIG. 1 is a diagram showing a schematic configuration of a symbol reading device. FIG. 2 is a view of the three-dimensional data acquisition unit of the symbol reading device shown in FIG. 1 as viewed in the axial direction. FIG. 3 is a diagram showing an example of image data converted from three-dimensional data by the image data conversion unit. FIG. 4 is a flowchart showing a method for reading symbols on a pipe in the first embodiment. FIG. 5 is a diagram showing a schematic configuration of a pipe symbol reading device according to the second embodiment. FIG. 6 is a diagram showing an example of how the acquired divided three-dimensional data is converted into connected image data in the symbol reading device shown in FIG. FIG. 7 is a diagram showing an example of extracted image data in which a part of the image data is extracted by the data extracting section in the symbol reading device shown in FIG. FIG. 8 is a flowchart showing a method for reading symbols on pipes in the second embodiment. FIG. 9 is a diagram showing a schematic configuration of a pipe symbol reading device according to the third embodiment. Figure 10 is a diagram showing an example of image data converted by the image data conversion unit in the symbol reading device described in Figure 9, where (a) shows an example of image data including contour image data, and (b) shows an example of image data including straight line portions converted from the contour image data. Figure 11 shows an example of image data in which straight line portions and embossed symbol image portions are emphasized, and image data in which images that are not to be read have been removed by an image data filter unit, where (a) shows an example of image data in which straight line portions and embossed symbol image portions are emphasized, and (b) shows an example of image data in which images that are not to be read have been removed. FIG. 12 is a flowchart showing a method for reading symbols on a pipe in the third embodiment. FIG. 13 is a diagram showing how, in another embodiment, image data of one or more revolutions is used to read a embossed symbol at a reading target portion located at a predetermined position in the opposite direction to one direction in which the embossed symbols are arranged relative to a reference symbol. FIG. 14 is a diagram showing an example of extracted image data obtained by extracting a part of image data by the data extracting section in the symbol reading device shown in FIG.

Each embodiment will be described below with reference to the drawings. In each drawing, the same parts are given the same reference numerals, and the description of the same parts will not be repeated. Note that the dimensions of the components in each drawing do not faithfully represent the actual dimensions of the components or the dimensional ratios of each component.

In the following description, the axial direction refers to the direction in which the axis P of the tube 99 extends. The radial direction refers to the direction perpendicular to the axis P of the tube 99. The circumferential direction refers to the direction in which the outer circumferential surface of the tube 99 extends when the tube 99 is viewed in the axial direction.

In addition, in the following description, the expressions "fixed," "connected," and "attached" (hereinafter referred to as "fixed") include not only cases where members are directly fixed to each other, but also cases where members are fixed via other members. In other words, in the following description, the expression "fixed" includes the meaning of direct and indirect fixation between members.

[Embodiment 1]
(Overall composition)
Fig. 1 is a diagram showing a schematic configuration of a symbol reading device 1 for a pipe 99 according to an embodiment of the present invention. Fig. 2 is a diagram showing a three-dimensional data acquisition unit 10 of the symbol reading device 1 shown in Fig. 1 as viewed in the axial direction. The symbol reading device 1 is a device for reading a rugged symbol 90 formed on an end surface 99a of a pipe 99 to be measured.

The pipe 99 is, for example, a cast iron pipe used as a water pipe. The pipe 99 has a cylindrical shape extending along the axis P. An uneven symbol 90 indicating the nominal diameter, manufacturing plant, manufacturing year, lot number, manufacturer, etc. of the pipe 99 is formed on the axial end face 99a of the pipe 99. The uneven symbol 90 is composed of a convex portion, a concave portion, or a combination of a convex portion and a concave portion. The end face 99a is part of the outer surface of the pipe 99 and is located at the end of the pipe 99 in the axial direction.

As shown in FIG. 2, the embossed symbols 90 are formed on the end surface 99a of the pipe 99 so as to be aligned in the circumferential direction. The embossed symbols 90 are formed on the end surface 99a of the pipe 99 by, for example, casting, laser cutting, or the like. The embossed symbols 90 include letters 91, figures 92, or a combination of letters 91 and figures 92. The letters 91 are words or numbers, etc. The figures 92 are pictographic marks, etc.

As shown in FIG. 1, the symbol reading device 1 has a three-dimensional data acquisition unit 10 and a control unit 30. The symbol reading device 1 acquires three-dimensional data of the relief symbol 90 formed on the end surface 99a of the pipe 99 by using the three-dimensional data acquisition unit 10 while rotating the pipe 99 around the axis P.

The three-dimensional data acquisition unit 10 has a rotation drive unit 5, a data acquisition unit main body 11, and a data storage unit 12.

The rotary drive unit 5 includes a plurality of roller parts 5a that rotatably support the tube 99 from below. The rotary drive unit 5 rotates the plurality of roller parts 5a to rotate the tube 99 around the axis P.

The data acquisition unit main body 11 uses a known light cutting method to measure two-dimensional data including radial position information on the end face 99a of the pipe 99 and height information at that position. As shown in FIG. 2, the data acquisition unit main body 11 measures the two-dimensional data on the end face 99a of the pipe 99 that is rotating relatively by the rotation drive unit 5. This allows the three-dimensional data acquisition unit 10 to acquire three-dimensional data including radial and circumferential position information on the end face 99a of the pipe 99 and height information at that position. The three-dimensional data includes three-dimensional data of the relief symbol 90 formed on the end face 99a.

The data storage unit 12 has a configuration capable of storing the three-dimensional data. The data storage unit 12 is, for example, a hard disk, SSD, RAM, USB memory, CD-ROM, etc. The data storage unit 12 may be a device or equipment of any configuration as long as it has a configuration capable of storing data. The three-dimensional data stored in the data storage unit 12 is output to the image data conversion unit 40 of the control unit 30.

(Control Unit)
The control unit 30 controls the reading of the embossed symbol 90 in the symbol reading device 1. The control unit 30 has a measurement control unit 20, a reading control unit 33, and a storage unit 75.

The measurement control unit 20 controls the acquisition of the three-dimensional data by the three-dimensional data acquisition unit 10, and also controls the rotation of the tube 99 by the rotation drive unit 5. Specifically, the measurement control unit 20 controls the rotation drive unit 5 so that the multiple roller units 5a rotate the tube 99 relatively in a direction opposite to one direction in which the uneven symbols 90 are arranged. In the example shown in FIG. 2, the measurement control unit 20 drives the multiple roller units 5a so that the tube 99 rotates in a counterclockwise direction, which is the opposite direction to the clockwise direction in which the uneven symbols 90 are arranged. The measurement control unit 20 also controls the three-dimensional data acquisition unit 10 so as to acquire the three-dimensional data of the uneven symbols 90 formed on the end surface 99a of the tube 99.

(Reading control section)
The reading control unit 33 reads the embossed symbol 90 formed on the end surface 99a of the pipe 99, using the three-dimensional data of the embossed symbol 90 acquired by the three-dimensional data acquisition unit 10. The reading control unit 33 has an image data conversion unit 40, a reference symbol identification unit 50, and a symbol reading unit 60.

Figure 3 is a diagram showing an example of image data 41 converted from the three-dimensional data by the image data conversion unit 40. As shown in Figure 3, the image data conversion unit 40 converts the three-dimensional data acquired by the three-dimensional data acquisition unit 10 into image data 41 in which the embossed symbols 90 are arranged in a straight line. The image data conversion unit 40 converts, for example, the three-dimensional data into image data 41 in which the height information of the embossed symbols 90 is expressed by color brightness. The image data 41 includes a embossed symbol image section 49 which is an image of the embossed symbol 90. The embossed symbol image section 49 is image data that displays the characters 91 and figures 92 of the embossed symbol 90.

The image data conversion unit 40 may perform image processing to make the embossed symbol image portion 49 clearer. The image processing may be, for example, a process of adjusting the range of color brightness relative to the height information, a binarization process, or the like. This allows the reference symbol identification unit 50 described below to easily identify the reference symbol 51 in the embossed symbol image portion 49, and the symbol reading unit 60 described below to easily read the embossed symbol 90 in the embossed symbol image portion 49.

The reference symbol identification unit 50 identifies the reference symbol 51 in the embossed symbol image unit 49. The reference symbol identification unit 50 identifies the reference symbol 51, for example, by comparing the reference symbol registration data stored in advance in the storage unit 75 with the image data of the embossed symbol 90 in the embossed symbol image unit 49. The reference symbol identification unit 50 identifies the reference symbol 51, for example, by comparing the degree of agreement of the shapes of the symbols. For example, in FIG. 3, the reference symbol identification unit 50 identifies a "water mark", which is a symbol that has a high degree of agreement of shape with the reference symbol registration data, as the reference symbol 51. The reference symbol identification unit 50 may identify a embossed symbol other than a "water mark" as the reference symbol 51 in the embossed symbol image unit 49. The reference symbol 51 is a symbol that serves as a reference when the symbol reading unit 60 starts the operation to read the embossed symbol 90.

As shown in FIG. 3, the symbol reading unit 60 reads the embossed symbol 90 in the reading target portion 61 of the embossed symbol image unit 49 using the reference symbol 51 as a reference. The reading target portion 61 is a portion of the embossed symbol image unit 49 that contains image data of the embossed symbol 90 to be read.

The symbol reading unit 60 may read only characters in the reading target unit 61. The symbol reading unit 60 may have the functionality of a known optical character recognition (OCR) system, for example. The symbol reading unit 60 may output the results of the reading to the storage unit 75 as symbol data.

For example, the symbol reading unit 60 reads the embossed symbol 90 in the reading target portion 61 located behind the reference symbol 51 in one direction, which is the arrangement direction of the embossed symbol 90, in the embossed symbol image portion 49 of the image data 41. In the example shown in FIG. 3, the symbol reading unit 60 reads the embossed symbol 90 in the reading target portion 61 located behind the "water mark" identified as the reference symbol 51. In the example shown in FIG. 3, the symbol reading unit 60 reads the characters "DS22F150GX112" in the reading target portion 61.

In addition to storing the reference symbol registration data, the memory unit 75 may store the symbol data output from the symbol reading unit 60. The memory unit 75 is, for example, a storage medium such as a hard disk, SSD, RAM, USB memory, or CD-ROM. The memory unit 75 may be a device or equipment of any configuration as long as it has a configuration capable of storing data. The memory unit 75 may be provided separately from the control unit 30.

According to the above-mentioned configuration, the three-dimensional data acquisition unit 10 can acquire the three-dimensional data of the embossed symbols 90 arranged in the circumferential direction on the end face 99a, which is the outer peripheral surface of the pipe 99. Then, the image data conversion unit 40 can convert the three-dimensional data into image data 41 in which the embossed symbols 90 (embossed symbol image portion 49) are arranged in a straight line. Then, the reference symbol identification unit 50 can identify the reference symbol 51 in the image data 41 that serves as a reference for starting to read the embossed symbols 90. The symbol reading unit 60 can read the embossed symbols 90 using the image data 41 and the reference symbol 51 as a reference. In this way, the symbol reading device 1 can read the embossed symbols 90 formed on the end face 99a of the pipe 99.

This allows the symbol reading device 1 to more accurately read the embossed symbol 90 on the pipe 99 from the image data 41. Moreover, even if the blank area disclosed in Patent Document 1 cannot be identified, the reference symbol 51 is identified in the image data 41 converted from the three-dimensional data, so acquisition of the three-dimensional data is not continued. Therefore, the reading time for the embossed symbol is not unnecessarily extended, and the embossed symbol 90 can be read in a shorter time.

Therefore, the symbol reading device 1 having the above-mentioned configuration can read the embossed symbol 90 formed on the outer surface of the pipe 99 with greater accuracy and can shorten the time required to read the embossed symbol.

Moreover, the symbol reading device 1 does not require a blank area as disclosed in Patent Document 1. Therefore, the symbol reading device 1 having the above-mentioned configuration can also read the embossed symbol 90 formed on the outer peripheral surface of the pipe 99 where the blank area cannot be identified. This makes it possible to realize a symbol reading device 1 with higher versatility.

Furthermore, as described above, the three-dimensional data acquisition unit 10 acquires the three-dimensional data of the uneven symbols 90 while relatively rotating the pipe 99 in the direction opposite to the one direction in which the uneven symbols 90 are arranged, so that the three-dimensional data of the uneven symbols 90 can be acquired in the one direction in which the uneven symbols 90 are arranged. Therefore, the uneven symbols 90 can be read more quickly and reliably.

In addition, as described above, the symbol reading unit 60 uses the image data 41 to read the embossed symbol 90 in the reading target portion 61 that is located behind the reference symbol 51 in one direction, which is the arrangement direction of the embossed symbol 90. This makes it possible to read the embossed symbol 90 more reliably.

(How to read pipe symbols)
Next, a method for reading the embossed symbol 90 formed on the end surface 99a of the pipe 99 using the symbol reading device 1 having the above-mentioned configuration (symbol reading method) will be described with reference to Fig. 4. Fig. 4 is a flowchart showing the symbol reading method in the first embodiment.

When the flow shown in FIG. 4 starts (START), first in step SA1, the rotation drive unit 5 of the three-dimensional data acquisition unit 10 rotates the pipe 99, and the data acquisition unit main body 11 acquires three-dimensional data by measuring the height information of the embossed symbol 90 on the end surface 99a. In the following step SA2, the image data conversion unit 40 converts the three-dimensional data into image data 41. The image data 41 includes a embossed symbol image portion 49.

Then, in step SA3, the reference symbol identification unit 50 identifies the reference symbol 51 from within the embossed symbol image portion 49.

In the next step SA4, the symbol reading unit 60 uses the reference symbol 51 as a reference for starting operation and reads the embossed symbol 90 in the reading target portion 61 of the embossed symbol image portion 49. Then, this flow ends (END).

Here, step SA1 corresponds to the three-dimensional data acquisition step, step SA2 corresponds to the image data conversion step, step SA3 corresponds to the reference symbol identification step, and step SA4 corresponds to the symbol reading step.

According to the above-mentioned method, three-dimensional data of the embossed symbols 90 arranged in the circumferential direction on the outer peripheral surface of the pipe 99 is acquired in step SA1, and image data 41 in which the embossed symbols 90 (embossed symbol image portion 49) are arranged in a straight line can be obtained from the three-dimensional data. Then, the reference symbol 51 can be identified in the embossed symbol image portion 49. Therefore, the embossed symbol 90 can be read in the reading target portion 61 of the embossed symbol image portion 49 using the reference symbol 51 as a reference.

This allows the symbol reading device 1 to more accurately read the embossed symbol 90 on the pipe 99 using the image data 41. Moreover, even if the symbol reading device 1 cannot identify a blank area as disclosed in Patent Document 1, it can identify the reference symbol 51 in the image data 41 converted from the three-dimensional data. Therefore, the acquisition of the three-dimensional data by the three-dimensional data acquisition unit 10 is not continued. Therefore, the time required to read the embossed symbol is not unnecessarily extended, and the embossed symbol 90 can be read in a shorter time.

Therefore, the above-mentioned symbol reading method can more accurately read the embossed symbol 90 formed on the outer surface of the pipe 99 and can shorten the time required to read the embossed symbol.

[Embodiment 2]
Fig. 5 shows a schematic configuration of a symbol reading device 200 according to the second embodiment. The configuration of a control unit 230 of the symbol reading device 200 according to this embodiment differs from the configuration of the control unit 30 of the symbol reading device 1 according to the first embodiment. In the following, the same components as those in the first embodiment are given the same reference numerals and their description is omitted, and only the components different from the first embodiment are described. Fig. 6 is a schematic diagram showing an example of how the acquired divided three-dimensional data 215 is converted into linked image data 241 in the symbol reading device 200.

As shown in FIG. 5, the symbol reading device 200 according to the second embodiment has a three-dimensional data acquisition unit 210 and a control unit 230.

As shown in Figures 5 and 6, the three-dimensional data acquisition unit 210 divides the acquired three-dimensional data into a predetermined data length, and outputs the divided data to the image data conversion unit 240 as divided three-dimensional data 215.

The three-dimensional data acquisition unit 210 may, for example, divide the acquired three-dimensional data in real time and output the divided data to the image data conversion unit 240 as divided three-dimensional data 215. The three-dimensional data acquisition unit 210 may also, for example, divide the three-dimensional data stored in the data storage unit 12 into a predetermined data length and output the divided data to the image data conversion unit 240 as divided three-dimensional data 215.

The control unit 230 has a measurement control unit 20, a reading control unit 233, and a memory unit 75. The reading control unit 233 has an image data conversion unit 240, a reference symbol identification unit 50, and a symbol reading unit 260.

The image data conversion unit 240 converts the multiple divided three-dimensional data 215 into concatenated image data 241 by concatenating the multiple divided three-dimensional data 215 in one direction, which is the arrangement direction of the concave-convex symbols 90. Except for concatenating the multiple divided three-dimensional data 215, the method of converting the multiple divided three-dimensional data 215 into concatenated image data 241 is the same as the method of converting three-dimensional data into image data 41 in embodiment 1. The concatenated image data 241 corresponds to the image data of the present invention.

The symbol reading unit 260 extracts a portion of the image data 41 and reads the embossed symbol 90 using the extracted image data. In detail, the symbol reading unit 260 has a data extraction unit 261 and a reading execution unit 262.

Figures 7 and 14 are diagrams showing an example of extracted image data 242 in which a portion of image data 41 is extracted by data extraction unit 261 in symbol reading device 200. As shown in Figures 7 and 14, data extraction unit 261 extracts a predetermined range of image data from linked image data 241 at a predetermined position from reference symbol 51 in the arrangement direction of embossed symbol 90 as extracted image data 242.

The specified position is a position that includes the portion to be read 61, and is, for example, a position that is preset based on the reference symbol 51. The specified range is a range that includes the portion to be read 61, and is, for example, a range whose size is preset. Within the specified range, thresholds are set for area, line length (including the vertical and horizontal lengths of characters), line thickness, circularity, etc., and the symbol reading unit 260 may not read it as a concave-convex symbol 90 if any one of these is below the threshold. When multiple image data of the specified range are extracted, the same threshold may be set for each extracted image data, or different thresholds may be set.

In the example shown in FIG. 7, the data extraction unit 261 extracts, from the concatenated image data 241 obtained by rotating the tube 99 multiple times, a range of a specified data length from the reference symbol 51 in the arrangement direction of the embossed symbols 90, that is, a specified data length range (predetermined range) including the reading target portion 61 with the reference symbol 51 being the "water mark" as the reference, as extracted image data 242. Therefore, in the example shown in FIG. 7, the predetermined position is the position immediately behind the reference symbol 51, the "water mark", in the arrangement direction of the embossed symbols 90.

In the example shown in FIG. 14, the data extraction unit 261 extracts image data of a predetermined range at a plurality of predetermined positions relative to the "water mark" which is the reference symbol 51 in the arrangement direction of the embossed symbol 90 in the concave-convex ...

The extraction of image data from the linked image data 241 by the data extraction unit 261 is not limited to the examples shown in Figures 7 and 14 above. In other words, the method of extracting image data from the linked image data 241 may be any method as long as the reading target portion 61 is included in the image data.

The reading execution unit 262 reads the embossed symbol 90 from the reading target portion 61 contained in the extracted image data 242 or 243.

According to the above-mentioned configuration, by dividing the three-dimensional data into multiple pieces and outputting the divided data to the image data conversion unit 240 as divided three-dimensional data 215, the volume of data output from the three-dimensional data acquisition unit 210 to the image data conversion unit 240 can be reduced. Therefore, the load of data processing and data transmission on the symbol reading device 200 can be reduced.

Moreover, by dividing the three-dimensional data into a predetermined data length, the reading control unit 233 can obtain the linked image data 241 including the reading target portion 61 in a shorter time. Therefore, the symbol reading device 200 can read the embossed symbol 90 in a shorter time.

In addition, by the data extraction unit 261 extracting the extracted image data 242, 243 from the linked image data 241, the data capacity of the image when reading the embossed symbol 90 can be reduced. Therefore, the load on the symbol reading device 200 when reading the embossed symbol 90 from the linked image data 241 can be further reduced.

In addition, image data of a specified range in which the embossed symbol 90 is to be read can be extracted from the linked image data 241 as the extracted image data 242 or 243, which makes it possible to prevent image data outside the specified range from being read by mistake. Therefore, the embossed symbol 90 to be read can be read more accurately from the extracted image data 242 or 243.

(How to read pipe symbols)
Next, a method for reading the embossed symbol 90 formed on the end surface 99a of the pipe 99 using the symbol reading device 200 having the above-mentioned configuration (symbol reading method) will be described with reference to Fig. 8. Fig. 8 is a flowchart showing the symbol reading method in the second embodiment.

When the flow shown in FIG. 8 starts (START), first, in step SB1, three-dimensional data is acquired by the three-dimensional data acquisition unit 210, similar to step SA1 in embodiment 1. In the following step SB2, the three-dimensional data is divided into data of a predetermined data length to generate divided three-dimensional data 215.

Then, in step SB3, the multiple divided 3D data 215 are linked in one direction, which is the arrangement direction of the concave-convex symbols 90, and converted into linked image data 241.

In step SB4, similar to step SA3 in embodiment 1, the reference symbol 51 is identified in the embossed symbol image portion 49.

In the next step SB5, the data extraction unit 261 extracts a predetermined range of image data from the concatenated image data 241 at a predetermined position from the reference symbol 51 in the arrangement direction of the concave-convex symbol 90. This results in the extracted image data 242 or 243.

In step SB6, the reading execution unit 262 reads the embossed symbol 90 from the reading target unit 61 using the extracted image data 242 or 243. Then, this flow ends (END).

Here, step SB1 corresponds to the 3D data acquisition step, step SB2 corresponds to the divided 3D data generation step, step SB3 corresponds to the image data conversion step, step SB4 corresponds to the reference symbol identification step, step SB5 corresponds to the data extraction step, step SB6 corresponds to the reading execution step, and steps SB5 and SB6 correspond to the symbol reading step.

According to the above-mentioned method, by dividing the three-dimensional data into multiple pieces and outputting the divided data to the image data conversion unit 240 as divided three-dimensional data 215, it is possible to reduce the amount of data output from the three-dimensional data acquisition unit 210 to the image data conversion unit 240. This makes it possible to reduce the load of data processing and data transmission on the symbol reading device 200.

In addition, a portion of the concatenated image data 241 is extracted as the extracted image data 242 or 243, and the embossed symbol 90 is read in the extracted image data 242 or 243, so the capacity of the image data used to read the embossed symbol 90 can be reduced. Therefore, the load on the symbol reading device 200 when reading the embossed symbol 90 from the concatenated image data 241 can be reduced.

In addition, image data of a specified range in which the embossed symbol 90 is to be read can be extracted from the linked image data 241 as the extracted image data 242 or 243, which makes it possible to prevent image data outside the specified range from being read by mistake. Therefore, the embossed symbol 90 to be read can be read more accurately from the extracted image data 242 or 243.

[Embodiment 3]
9 shows a schematic configuration of a symbol reading device 300 according to embodiment 3. The configuration of a control unit 330 of the symbol reading device 300 according to this embodiment is different from the configuration of the control unit 30 of embodiment 1. In the following, the same components as those in embodiment 1 are denoted by the same reference numerals and their description is omitted, and only the components different from embodiment 1 will be described.

As shown in FIG. 9, the symbol reading device 300 according to the third embodiment has a three-dimensional data acquisition unit 10 and a control unit 330.

The three-dimensional data acquisition unit 10 acquires three-dimensional data in which the inner wall 397 and the outer wall 398 of the pipe 99 each form the outline of the area in which the uneven symbol 90 is read.

The control unit 330 has a measurement control unit 20, a reading control unit 333, and a memory unit 75. The reading control unit 333 has an image data conversion unit 340, a reference symbol identification unit 50, an image data filter unit 385, and a symbol reading unit 60.

Figure 10 is a diagram showing an example of image data 341A, 341B converted by the image data conversion unit 340. As shown in Figure 10 (a), the image data conversion unit 340 converts the three-dimensional data including the contour into image data 341A. The image data 341A includes a contour image portion 345 in which the contour is converted into an image.

As shown in FIG. 10(b), the image data conversion unit 340 converts the image data 341A into image data 341B in which the contour image portion 345 is converted into a straight line portion L. The straight line portion L is, for example, a straight line image in which the contour image portion 345 is thickened and emphasized. The straight line portion L makes it possible to more clearly distinguish between the area including the concave-convex symbol image portion 49 and the outside of that area.

Figure 11 shows an example of image data 341C in which the straight line portion L and the embossed symbol image portion 49 are emphasized, and image data 341D in which the image data filter unit 385 has removed the image 347 that is not to be read. As shown in Figure 11 (a), the image data filter unit 385 performs binarization processing or the like on the image data 341B to generate image data 341C in which the straight line portion L and the embossed symbol image portion 49 are emphasized.

As shown in FIG. 11(b), the image data filter unit 385 generates image data 341D by removing image 347 that is not to be read from image data 341C. The image 347 that is not to be read includes not only symbols, but also contour image portion 345, straight line portion L, etc. For example, in FIG. 11, the image data filter unit 385 removes image 347 of a specific figure in straight line portion L and concave-convex symbol image portion 49, which are not to be read, from image data 341C.

The image data filter unit 385 can set thresholds for parameters such as image shape, length, area, circularity, and brightness differences, and select images 347 below the thresholds as images not to be read.

The above-described configuration makes it possible to clearly distinguish the difference between the embossed symbol image portion 49 and the contour image portion 345 in the image data 341A. Furthermore, the straight line portion L with the contour image portion 345 emphasized makes it possible to clearly distinguish the difference between the embossed symbol image portion 49 and the straight line portion L in the image data 341B. Therefore, the difference between the embossed symbol image portion 49 and the straight line portion L can also be clearly distinguished in the image data 341C obtained by performing a binarization process or the like on the image data 341B. This allows the image data filter unit 385 to more reliably remove the image 347 that is not to be read from the image data 341C.

By generating image data 341D by image data filter unit 385 as described above, symbol reading unit 60 can read embossed symbols 90 in reading target area 61 from which images 347 that are not to be read have been removed. Therefore, only embossed symbols 90 that are to be read can be read with high accuracy in image data 341D.

(How to read pipe symbols)
Next, a method for reading the embossed symbol 90 formed on the end surface 99a of the pipe 99 using the symbol reader 300 having the above-mentioned configuration (symbol reading method) will be described with reference to Fig. 12. Fig. 12 is a flowchart showing the symbol reading method in the third embodiment.

When the flow shown in FIG. 12 starts (START), first in step SC1, the three-dimensional data acquisition unit 10 acquires three-dimensional data in which the inner wall 397 and the outer wall 398 of the pipe 99 each become the contours of the area in which the embossed symbol 90 is read. In the following step SC2, the three-dimensional data is converted into image data 341A having a contour image portion 345. Then, the image data 341A is converted into image data 341B having a straight line portion L.

Then, in step SC3, similar to step SA3 in embodiment 1, the reference symbol identification unit 50 identifies the reference symbol 51 in the embossed symbol image unit 49.

In the next step SC4, the image data filter unit 385 generates image data 341C in which the straight line portion L and the embossed symbol image portion 49 are emphasized. The image data filter unit 385 then removes the image 347 that is not to be read from the image data 341C to generate image data 341D.

In step SC5, the image data 341D is used to read the embossed symbol 90 in the reading target area 61. Then, this flow ends (END).

Here, step SC1 corresponds to the three-dimensional data acquisition step, step SC2 corresponds to the image data conversion step, step SC3 corresponds to the reference symbol identification step, step SC4 corresponds to the image filter step, and step SC5 corresponds to the symbol reading step.

The above-mentioned method makes it possible to clearly distinguish the difference between the embossed symbol image portion 49 and the contour image portion 345 in the image data 341A. Furthermore, the straight line portion L with the contour image portion 345 emphasized makes it possible to clearly distinguish the difference between the embossed symbol image portion 49 and the straight line portion L in the image data 341B. Therefore, the difference between the embossed symbol image portion 49 and the straight line portion L can also be clearly distinguished in the image data 341C obtained by performing a binarization process or the like on the image data 341B. This makes it possible to more reliably remove the image 347 that is not to be read from the image data 341C.

By generating the image data 341D as described above, the symbol reading unit 60 can read the embossed symbol 90 in the reading target area 61 from which the image 347 that is not to be read has been removed. Therefore, only the embossed symbol 90 to be read in the image data 341D can be read with high accuracy. Therefore, the embossed symbol 90 formed on the outer surface of the pipe 99 can be read with high accuracy.

Other Embodiments
Although the embodiment of the present invention has been described above, the above-mentioned embodiment is merely an example for carrying out the present invention. Therefore, the present invention is not limited to the above-mentioned embodiment, and it is possible to carry out the above-mentioned embodiment by appropriately modifying it within the scope of the gist of the present invention.

In each of the above embodiments, the symbol reading unit 60, 260 reads the embossed symbol 90 in the reading target portion 61 located in one direction, which is the arrangement direction of the embossed symbol 90, relative to the reference symbol 51 in the image data 41 or the linked image data 241.

Figure 13 shows how image data of one or more revolutions is used to read a rugged symbol 90 at a target reading area located at a predetermined position in the opposite direction to the one direction in which the rugged symbols are arranged relative to the reference symbol.

As shown in FIG. 13, the symbol reading unit may read the embossed symbol 90 in the reading target portion located at a predetermined position in the opposite direction to the one direction in which the embossed symbols are arranged relative to the reference symbol, using image data of one or more revolutions converted by the image data conversion unit from three-dimensional data of one or more revolutions acquired by the three-dimensional data acquisition unit.

As a result, even if the reference symbol in a previous revolution is erroneously determined to be another symbol and the reference symbol cannot be identified in the image data obtained from the three-dimensional data acquired while the tube is rotated one or more revolutions, the embossed symbol 90 can be read in the reading target portion located at a specified position in the opposite direction to the one direction in which the embossed symbols are arranged, relative to the reference symbol identified by the reference symbol identification unit in a subsequent revolution. Therefore, the embossed symbol can be read more reliably.

The symbol reading device 1 of the first embodiment may have at least a part of the configuration of the symbol reading device 200 of the second embodiment and the configuration of the symbol reading device 300 of the third embodiment. Furthermore, the symbol reading device 200 of the second embodiment may have at least a part of the configuration of the symbol reading device 1 of the first embodiment and the configuration of the symbol reading device 300 of the third embodiment. Furthermore, the symbol reading device 300 of the third embodiment may have at least a part of the configuration of the symbol reading device 1 of the first embodiment and the configuration of the symbol reading device 200 of the second embodiment.

In each of the above embodiments, the reference symbol identification unit 50 identifies one reference symbol 51 from the embossed symbol image portion 49. However, the reference symbol identification unit may identify multiple reference symbols. This allows the symbol reading unit to read the embossed symbol in the reading target portion using the other reference symbols as a reference even if one reference symbol is unclear.

In each of the above embodiments, the symbol reading unit 60, 260 reads the embossed symbol 90 in the reading target area 61 using the reference symbol 51 as a reference. However, the symbol reading unit may read the embossed symbol in the embossed symbol image area using the reference symbol as a reference without specifying the reading target area.

In each of the above embodiments, the reading target portion 61 is located in one direction, which is the arrangement direction of the embossed symbols 90, with the reference symbol 51 as a reference. However, the reading target portion may be located a predetermined distance away from the reference symbol in the one direction. The position, size, range, etc. of the reading target portion may be determined depending on the type of pipe to be measured.

In each of the above embodiments, the reading control unit 33, 233, 333 does not have a function of outputting. However, the reading control unit may further have an output unit that outputs the symbol read by the symbol reading unit to the outside of the symbol reading device. This makes it easier to read embossed symbols. The output unit may output to a display unit included in the symbol reading device without outputting to the outside of the symbol reading device. The display unit may display the symbol read by the symbol reading unit.

In each of the above embodiments, the pipe 99 is a cast iron pipe used as a water pipe. However, the pipe may be a pipe other than a cast iron pipe. The pipe may be a pipe made of other metals, such as steel, stainless steel, etc. The pipe may also be a pipe made of other resins, such as polyvinyl chloride. The pipe may be a pipe made of mortar, concrete, etc. The pipe may be a pipe other than a water pipe.

In the second embodiment, the three-dimensional data acquisition unit 10 divides the three-dimensional data to generate divided three-dimensional data 215. Then, the image data conversion unit 240 converts the divided three-dimensional data 215 into concatenated image data 241. However, the three-dimensional data acquisition unit does not have to generate divided three-dimensional data from the three-dimensional data. In this case, the image data conversion unit converts the three-dimensional data that is not divided three-dimensional data into image data.

In the second embodiment, the control unit 230 has a data extraction unit 261. The data extraction unit 261 extracts the extracted image data 242 or 243 from the linked image data 241. However, the data extraction unit may extract the extracted image data from image data that is not linked image data. The control unit may not extract the extracted image data from the image data. In other words, the control unit may not include a data extraction unit.

In the third embodiment, the image data conversion unit 340 converts the contour image portion 345 into a straight line portion L. However, the image data conversion unit does not have to convert the contour image portion into a straight line portion.

In the third embodiment, the image data filter unit 385 generates image data 341C by performing binarization processing or the like on image data 341B that includes straight line portion L. However, the image data filter unit may also generate image data in which the contour image portion is emphasized by performing binarization processing or the like on image data that includes the contour image portion.

In the third embodiment, the image data filter unit 385 emphasizes the straight line portion L and the embossed symbol image portion 49, etc., and removes the image 347 that is not to be read from the image data 341C. However, the image data filter unit does not have to perform the image processing for emphasis. In this case, the image data filter unit may remove the image that is not to be read from the image data before the image processing for emphasis is performed. The image data filter unit does not have to remove the image that is not to be read from the image data.

In the third embodiment, the symbol reading unit 60 reads the embossed symbol 90 using image data 341D from which images 347 not to be read have been removed. However, the symbol reading unit may also read the embossed symbol from image data from which images not to be read have not been removed. In other words, the symbol reading unit may read the embossed symbol from image data that includes contour image portions and straight line portions from which images not to be read have not been removed, or from image data that has been subjected to image processing for emphasis.

In each of the above embodiments, the three-dimensional data acquisition unit 10, 210 rotates the pipe 99 around the axis P by the rotation drive unit 5 while the data acquisition unit main body 11 acquires three-dimensional data of the relief symbol 90 formed on the end face 99a of the pipe 99. However, the three-dimensional data acquisition unit may also acquire three-dimensional data by rotating the data acquisition unit main body relative to the fixed end face of the pipe. In this case, the three-dimensional data acquisition unit has a movement mechanism that moves the data acquisition unit main body relative to the pipe.

The present invention can be used in a symbol reading device that reads a rugged symbol formed by recesses or protrusions aligned in one circumferential direction on the outer surface of a pipe.

Reference Signs List 1, 200, 300 Symbol reading device 5 Rotation drive unit 5a Roller unit 10, 210 Three-dimensional data acquisition unit 11 Data acquisition unit main body 12 Data storage unit 20 Measurement control unit 30, 230, 330 Control unit 33, 233, 333 Reading control unit 40, 240, 340 Image data conversion unit 41, 341A, 341B, 341C, 341D Image data 49 Raised symbol image unit 50 Reference symbol identification unit 51 Reference symbol 60, 260 Symbol reading unit 61 Reading target unit 75 Storage unit 90 Raised symbol 91 Character 92 Figure 99 Pipe 99a End surface 215 Divided three-dimensional data 241 Linked image data 242, 243 Extracted image data 261 Data extraction unit 262 Reading execution unit 345 Contour image unit 347 Images not to be read 385 Image data filter unit 397 Inner wall 398 Outer wall L Straight section D Thickness of end face of pipe

Claims (9)

A symbol reading device for reading a rugged symbol formed on an outer surface of a pipe by recesses or protrusions arranged in one circumferential direction,
a three-dimensional data acquisition unit that acquires three-dimensional data of the unevenness symbol by measuring a height of the unevenness symbol with respect to an outer surface of the pipe while rotating the pipe relatively around an axis;
an image data conversion unit that converts the acquired three-dimensional data into image data in which the concave-convex symbols are arranged in a straight line;
a reference symbol identification unit that identifies a reference symbol in the image data as a reference for starting reading of the embossed symbol;
a symbol reading unit that reads the embossed symbol using the image data and the reference symbol as a reference;
having
The symbol reading unit is
a data extraction unit that extracts image data of a predetermined range from the reference symbol at a plurality of predetermined positions in an arrangement direction of the embossed symbol in the image data;
a reading execution unit that reads the embossed symbol using the image data of the predetermined range extracted by the data extraction unit;
having
Pipe symbol reader. 2. The pipe symbol reading device according to claim 1,
The three-dimensional data acquisition unit acquires three-dimensional data of the uneven symbols while relatively rotating the tube in a direction opposite to the one direction which is a direction in which the uneven symbols are arranged.
Pipe symbol reader . 2. The pipe symbol reading device according to claim 1,
the three-dimensional data acquisition unit acquires three-dimensional data of the unevenness symbol while relatively rotating the pipe about an axis line by one or more revolutions;
the symbol reading unit uses the image data to read a rugged symbol located at a predetermined position in a direction opposite to the one direction, which is an arrangement direction of the rugged symbols, with respect to the reference symbol;
Pipe symbol reader. 2. The pipe symbol reading device according to claim 1,
the three-dimensional data acquisition unit divides the three-dimensional data into a predetermined data length and outputs the divided three-dimensional data;
The image data conversion unit connects a plurality of the divided three-dimensional data to convert the data into the image data.
Pipe symbol reader. 2. The pipe symbol reading device according to claim 1,
an image data filter unit that removes specific symbol data from the image data to generate image data for reading the embossed symbol by the symbol reader unit;
Pipe symbol reader. 2. The pipe symbol reading device according to claim 1,
The three-dimensional data acquisition unit includes:
As the three-dimensional data, three-dimensional data is acquired in which the inner wall and the outer wall of the pipe each become the outline of an area in which the uneven symbol is read;
The image data conversion unit
converting the contour in the image data into a straight line portion that enables a distinction between the region and the outside of the region;
Pipe symbol reader. A method for reading a symbol that reads a rugged symbol formed on an outer surface of a pipe by recesses or protrusions aligned in one circumferential direction, comprising:
a three-dimensional data acquisition step of acquiring three-dimensional data of the unevenness symbol by measuring a height of the unevenness symbol with respect to an outer surface of the pipe while rotating the pipe relatively around an axis;
an image data conversion step of converting the three-dimensional data acquired in the three-dimensional data acquisition step into image data in which the concave-convex symbols are arranged in a straight line;
a reference symbol specifying step of specifying a reference symbol serving as a reference for starting reading of the embossed symbol in the image data converted in the image data converting step;
a symbol reading step of reading the embossed symbol using the image data and the reference symbol identified in the reference symbol identifying step as a reference;
having
The symbol reading step includes:
a data extraction step of extracting image data of a predetermined range from the reference symbol at a plurality of predetermined positions in an arrangement direction of the embossed symbol in the image data obtained in the image data conversion step;
a reading execution step of reading the embossed symbol using the image data of the predetermined range extracted in the data extraction step;
having
How to read pipe symbols. The method for reading symbols on a pipe according to claim 7 ,
a divided three-dimensional data generating step of dividing the three-dimensional data acquired in the three-dimensional data acquiring step into a predetermined length to generate divided three-dimensional data;
The image data conversion step connects a plurality of the divided three-dimensional data generated in the divided three-dimensional data generation step to convert the data into the image data.
How to read pipe symbols . The method for reading symbols on a pipe according to claim 7 ,
In the three-dimensional data acquisition step,
As the three-dimensional data, three-dimensional data is acquired in which the inner wall and the outer wall of the pipe each become the outline of an area in which the uneven symbol is read;
In the image data conversion step,
converting the contour in the image data into a straight line portion that enables a distinction between the region and the outside of the region;
How to read pipe symbols.

Images