JP2011090523A - Method and device for reading mark attached to surface of cylindrical article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To newly propose a method and a device for reading a mark attached to the surface of a cylindrical article moving while rolling. <P>SOLUTION: A mark attached to the surface of a cylindrical article moving while rolling on the upper face of a rolling surface is efficiently read by imaging the mark from the lower direction. That is, the cylindrical article is photographed from the lower face side of the rolling surface. The rolling surface is configured of a rail-shaped member by using a transparent member for enabling photographing from the lower part. Thus, the mark section can be surely captured. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a technique for optically reading and decoding an automatic recognition code. In particular, the present invention relates to a technique for reading and decoding an optical automatic recognition code attached to a cylindrical article while the target article is rolling.

  The inventors of the present application have so far proposed a unique optical recognition code (hereinafter referred to as “color arrangement code”) that represents data only by the arrangement of colors in Japanese Patent Application No. 2006-196705. Since these represent data only in the order of color arrangement, there is a degree of freedom in the size, shape, etc. of each cell (color range). Therefore, rough marking that does not depend on a printer or the like is possible, and decoding is possible even if the code portion is deformed. By utilizing such a feature, it is possible to directly mark a color arrangement code on the surface of a “cylindrical article” that is difficult to mark with a printer or the like, regardless of sticking a sticker or the like. .

  On the other hand, in the manufacturing process of a cylindrical article, the cylindrical article may be rolled and conveyed, and the color arrangement code may need to be read at the conveyance stage. Here, as a method of reading the optical automatic recognition code attached to the rotating cylindrical article, there are the following patent documents.

  For example, Patent Document 1 discloses a device that rotates a tire, detects a code by a bar code display detection device, and reads the detected code. According to this, it is possible to reduce the cost of the tire barcode reading device without requiring an expensive camera that can capture a wide range of images.

  Patent Document 2 discloses an information reading device for a cylindrical container that can automatically and reliably read characters or barcodes attached to the surface of the cylindrical container regardless of the display mode of characters or the like. ing. In any of these methods, the optical automatic recognition code is read while the cylindrical article is rotating at a fixed position. As described above, there is no known technique for reading the optical automatic identification code attached to the surface of the article while the cylindrical article is “moving while rolling”.

Patent No.4202870 Japanese Patent No. 4157906

  As described above, a technique for reading an optical automatic identification code attached to the surface of an article while the cylindrical article is moving while rolling has not been known. Considering the color arrangement code as an example of a method for realizing this, a method of arranging a CCD camera or the like in the “facing direction” on the rolling cylindrical article, capturing a moving image of the surface of the cylindrical article, and reading the color arrangement code Can be considered. The “facing direction” refers to a state in which the cylindrical article and the imaging device that captures the color arrangement code attached thereto are arranged in the same direction with respect to the rolling surface (see FIG. 1). . In this case, the color arrangement code attached to the surface of the cylindrical article that is moving while rolling can be captured only when the phase of the rolling rotation is limited. In other words, the color arrangement code can be captured only when the color arrangement code attached to a part of the surface of the cylindrical article has come to a position facing the camera successfully (state A in FIG. 1). In other words, if the color arrangement code is hidden behind (state B in FIG. 1), the image cannot be captured well, and the color arrangement code is oblique to the camera (state C in FIG. 1). This causes problems such as blurring of the image.

  An image that can be taken by a normal CCD camera or the like is generally 30 frames (30 fps) per second. Therefore, when the rolling speed of the cylindrical article is high, the color arrangement code appears in the direction of the camera, and the period during which capture is possible becomes even shorter. Therefore, it is considered that it becomes more difficult to match the capturing timing with the timing when the color arrangement code is directed toward the camera.

  This tendency becomes even more pronounced as the radius of the cylindrical article decreases. When the radius of the cylindrical article is small, the time that the color array code is facing the camera is further shortened, and when the radius is small, the time interval at which the color array code appears on the camera side is shortened. Therefore, it is thought that the chance to capture increases. However, since the time during which the color arrangement code appears on the camera side and can be captured becomes even shorter, it becomes more difficult to match the timing at which the color arrangement code appears with the timing at which the color arrangement code appears on the camera side.

  On the other hand, when the radius of the cylindrical article is large, it is considered that the time during which the color arrangement code appears on the camera side and can be captured is generally long. However, in this case, the time interval at which the color arrangement code appears on the camera side and is ready to be captured becomes long, and so-called “waiting” states tend to increase. For this reason, it may be difficult to quickly image the color arrangement code.

  Thus, an effective method for capturing and decoding a color arrangement code on a cylindrical article rolling on a predetermined rolling surface “while moving while rolling” is not yet known. Therefore, in reality, it has been necessary to devise such as rotating the cylindrical article at a fixed position (Patent Document 2).

  Therefore, the present invention has been made based on the above studies, and provides a new method and apparatus for reading a color arrangement code attached to the surface of a cylindrical article that is moving while rolling. Although the color arrangement code is described here as an example, other optical automatic recognition codes such as a barcode may be attached to the target cylindrical article. Moreover, it is not limited to the optical automatic recognition code, and may be OCR numbers and characters. The present invention can be applied to any mark as long as it is optically recognized from an image.

(1) In order to achieve the above object, the present invention provides a method for reading a mark attached to the surface of a cylindrical article that moves while rolling on the upper surface of the rolling surface. A method for reading a mark attached to a surface of the cylindrical article, comprising: an imaging step of imaging the mark by means.

(2) Further, in the method for reading a mark according to (1), the present invention may be configured such that all or a part of the rolling surface is made of a transparent member, and the imaging step moves the cylinder on the transparent member. The mark attached to the surface of the shaped article is imaged from the lower side of the transparent member, and the mark attached to the surface of the cylindrical article is read.

(3) Moreover, the present invention provides the method for reading a mark according to (1), wherein all or a part of the rolling surface is constituted by a net-like article, and the imaging step moves on the net-like article. The method of reading a mark attached to the surface of the cylindrical article, wherein the mark attached to the surface of the cylindrical article is imaged from below the net-like article.

(4) Moreover, the present invention provides the mark reading method according to (1), wherein all or part of the rolling surface is formed in a rail shape, and the imaging step is performed on the cylindrical article that moves on the rail. The mark attached to the surface of the cylindrical article is imaged from below the rail, and the mark attached to the surface of the cylindrical article is read.

(5) Further, in the automatic mark reading method according to any one of (1) to (4), the present invention prevents background reflection in the upward direction of the cylindrical article moving on the rolling surface. A method of reading a mark attached to the surface of the cylindrical article, wherein a light shielding plate is arranged.
(6) Moreover, this invention is the mark automatic reading method in any one of (1) to (5), When there are two or more said cylindrical articles, the moving speed of each said cylindrical article is the following formula | equation. A method of reading a mark attached to the surface of the cylindrical article, characterized by having a speed adjusting step for adjusting so as to satisfy.

(Formula 1) V <D / f (where D is the diameter of the cylindrical article and f is the frame interval of the imaging means)
(7) Further, the present invention provides an apparatus for reading a mark attached to the surface of a cylindrical article that moves while rolling on the upper surface of the rolling surface, and an imaging means for imaging the mark attached to the surface of the cylindrical article. And the imaging means is arranged on the lower surface side of the rolling surface, and is a device for reading a mark attached to the surface of the cylindrical article.

(8) Further, in the apparatus for reading a mark according to (7), the present invention provides a surface of the cylindrical article, wherein all or part of the rolling surface is made of a transparent member. It is a device that reads the attached mark.

(9) Further, in the apparatus for reading a mark according to (7), the present invention provides the surface of the cylindrical article, wherein all or part of the rolling surface is formed of a net-like article. It is a device that reads the mark attached to.

(10) Further, in the apparatus for reading a mark according to (7), the present invention provides a surface of the cylindrical article characterized in that all or part of the rolling surface is formed in a rail shape. It is a device that reads the attached mark.

(11) Further, in the apparatus for reading a mark according to any one of (7) to (10), the present invention further includes a light shielding unit for preventing reflection of a background. It is a device that reads marks on the surface.

(12) Further, according to the present invention, in the apparatus for reading the mark according to any one of (7) to (11), when there are a plurality of front cylindrical articles, the moving speed of each cylindrical article is as follows: An apparatus for reading a mark attached to the surface of the cylindrical article, characterized by comprising speed adjusting means for adjusting to satisfy the equation.

(Formula 1) V <D / f (where D is the diameter of the cylindrical article and f is the frame interval of the imaging means)
(13) Further, in the mark reading apparatus according to (12), in the present invention, the speed adjusting unit adjusts an angle of a rolling surface in the conveying unit, so that the moving speed of the cylindrical article is as follows. An apparatus for reading a mark attached to a surface of the cylindrical article, wherein the mark is adjusted to satisfy an expression.

(Formula 1) V <D / f (where D is the diameter of the cylindrical article and f is the frame interval of the imaging means)

  As described above, according to the present invention, the color arrangement code attached to the surface of the cylindrical article that is moving while rolling can be reliably read.

It is explanatory drawing in the case of imaging from the direction which faces a cylindrical article. It is explanatory drawing showing a cycloid curve. It is explanatory drawing showing a cycloid curve. It is explanatory drawing in the case of imaging from the downward direction of a cylindrical article. It is explanatory drawing explaining the mode of a capture when multiple cylindrical articles are rolling continuously. It is explanatory drawing about the reading apparatus of the color arrangement | sequence code attached | subjected to the cylindrical article | item which moves while rolling.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings.

Examination of the imaging direction of the first code Normally, when imaging the color arrangement code, the cylindrical article 12 and the CCD camera 14 that captures the color arrangement code 16 on the rolling surface 10 are: In other words, they are arranged on the same side (see FIG. 1). This arrangement state is referred to as “facing” the CCD camera 14 with respect to the cylindrical article 12 in the present embodiment. The color array code is read (decoded) by processing and analyzing a two-dimensional image captured using an area sensor such as a CCD installed in the “facing” direction. The image in this case is a “still image”. However, if decoding is performed using each frame image (still image) of the captured moving image, the still image with the optimum conditions for various variations during camera imaging Can be used, and reliable decoding becomes possible.

  However, when reading a code attached to the surface of a moving object while rolling, there is an adverse condition that the object (cylindrical article 12) is moving and the timing at which the color arrangement code can be captured is limited. It will overlap. Therefore, it can be said that moving image capture that obtains as many still images as possible is desirable. Specifically, since “the object is moving”, the movement of the object during the shutter time (exposure time) leads to a problem that “image blur” occurs. In such a case, it is usually necessary to take measures such as reducing the shutter speed or reducing the blur amount by strobe light emission. Further, “the timing at which capture can be performed is limited” is specifically for the following reason. That is, if the color arrangement code on the surface of the cylindrical article is directly facing the camera, it can be captured naturally, but it is difficult to capture in the opposite direction (180 °) or the horizontal direction (90 °). Referring to FIG. 1, when the color arrangement code reaches the position A, it can be captured, but when it is at the position B or C, it becomes difficult to capture the color arrangement code. Assuming that the capture image limit (decodeable phase) within the range of ± 15 ° with respect to the camera's right angle can be decoded, the decodeable timing is within the range of 30 ° during one rotation of the cylinder. 360.

  Under such conditions, in order to capture the image of the color arrangement code more reliably, “the cylindrical article surely captures one or more frames during the state of the decodable phase” or “the cylindrical article A method of adjusting the frame rate and the time phase in conjunction with the rotation period of “the frame rate” is conceivable. However, the method of “adjusting the frame rate and time phase” is not practical because it requires control by capturing the positional relationship of the target cylindrical article and requires a large-scale control mechanism. On the other hand, in order to “capture one or more frames reliably while the cylindrical article is in a decodable phase state”, a camera that satisfies the frame rate necessary for that is required. Here, the frame rate of a normal video movie is 30 fps, and 30 still images are captured per second. Therefore, for example, when the rolling speed is high, it is not always possible to reliably capture one frame or more during the decodable phase state. There are high frame rate cameras with high frame rates, but they are expensive because of the special camera. In addition, when a high frame rate camera is used, the number of images to be handled becomes enormous, and the image processing side apparatus becomes large and expensive. Furthermore, depending on the diameter of the actual cylindrical article and the conveyance rolling speed, there are severe conditions that cannot be caught by a general high frame rate camera.

  As described above, when reading the code attached to the surface of the cylindrical article that moves while rolling, it is preferable to read the code using the image captured from the “facing direction” to the cylindrical article. Absent.

  On the other hand, it is known that “points” on the surface of an object moving while rolling draw a cycloid curve. The locus on the surface of the article when the cylindrical article is viewed from the axial direction of the rotating shaft of the cylindrical article is shown in FIGS. In FIG. 2, the horizontal axis (x axis) represents the position on the rolling surface 10 in FIG. 1, and the height (y axis) represents the height (distance) from this rolling surface. As shown in FIGS. 2 and 3, it is well known that the points on the surface of the cylindrical article draw a cycloid curve while rolling on the rolling surface 10. Since the color arrangement code in the present embodiment is also attached to the surface of the cylindrical article that moves while rolling, a cycloid curve as shown in FIGS. 2 and 3 is drawn.

  As is apparent from the cycloid curves in FIGS. 2 and 3, the moving speed differs greatly when the color arrangement code attached to the surface of the cylindrical article is viewed from above and when viewed from below. . That is, when viewed from above, the moving speed of the color arrangement code attached to the surface is large (twice the moving speed of the cylindrical article). This “viewing from above” means that the cylindrical article 12 and the CCD camera 14 are arranged on the same side with respect to the rolling surface as shown in FIG. It is. On the other hand, FIG. 3 shows an explanatory diagram of an arrangement for capturing the color arrangement code from the “downward direction”. In this way, when the color arrangement code is viewed from the lower direction, the movement speed of the color arrangement code is low, and it stops for a moment at the lowest point (the point where the cylindrical article 12 is in contact with the rolling surface 10). However, the forward and backward movement is slow in the traveling direction (x direction in FIG. 2), and is almost in the vertical direction (y direction in FIG. 2).

  The inventor of the present application pays attention to such a feature, and as a first feature of the present embodiment, the direction of imaging the code attached to the surface of the cylindrical article that moves while rolling is defined as “downward direction of the object”. ", We have developed a method that enables reliable imaging of color array codes. FIG. 4 shows an explanatory diagram of such a method of imaging from below. As shown in FIG. 4, a cylindrical article 12 and a CCD camera 14 are disposed across the rolling surface 10. In this case, a part or all of the rolling surface 10 is made of a transparent member such as glass, and the CCD camera 14 is connected to the color array code 16 on the cylindrical article 12 from below through the transparent rolling surface 10. Is captured. In addition, a part or all of the rolling surface 10 may not be a transparent member such as glass but may be a net-like one. Alternatively, a rail-shaped member may be arranged so that an image can be captured from between them. According to such a capture from the lower direction, as described above, the movement of the color arrangement code 16 stops for a moment at the point of contact with the rolling surface 10, so that it is captured without causing a blur due to the movement. Can be considered.

  Specifically, moving image capture is performed from “downward” by “long shutter speed”. However, even if “long time” is assumed, if the frame rate is 30 fps, the shutter speed is 1/30 fps at the longest.

  Here, a case where the frame rate is 30 fps and the shutter speed is 1/30 fps will be described. The fact that the shutter speed is 1/30 fps while the frame rate is 30 fps theoretically means that capture is always performed. Therefore, capture is always performed when the color arrangement code attached to the surface of the cylindrical article comes to the lowermost position. That is, this can be solved for the above-mentioned problem that “timing at which the color arrangement code can be captured is limited”. As for image blur, the cylindrical article is moving at 1/30 fps, but the movement is slow near the lowest point and stops momentarily at the lowest point. While this color arrangement code appears on the image of the camera, the main movement of the color arrangement code is the direction of moving toward and away from the camera. That is, the movement of the color arrangement code is not in the horizontal direction parallel to the rolling direction. Therefore, it is expected that the finally captured image will be an image close to the state where the image of the color arrangement code is stationary at the lowest point. In other words, this can be solved for the above-mentioned problem of “image blurring”.

Further, in the case where a plurality of cylindrical articles having different diameters are moving when the cylindrical article is imaged from the “facing direction”, it is necessary to adjust the focus (focus) of the imaging device for each article having a different diameter. is there. When focusing on a large diameter object, the color arrangement code attached to the surface of a cylindrical article with a small diameter cannot be imaged. Conversely, when focusing on a small diameter object, the diameter is large. This is because the color arrangement code attached to the surface of the cylindrical article is blurred. On the other hand, if an image is taken from the “downward direction” of the cylindrical article, it is only necessary to focus on the portion where the article contacts the rolling surface 10 even if the diameter of the moving cylindrical article is not uniform. There is no need to adjust the focus for each cylindrical article having a different diameter.
As described above, by capturing an image from the “downward direction” of the cylindrical article that moves while rolling, the color arrangement code attached to the surface of the cylindrical article can be reliably captured.

Second Method for Distinguishing from Background As in this embodiment, when the image is taken from below the cylindrical article, the trajectory of the movement of the target cylindrical article is imaged, and at the same time, the background is also superimposed. It will be. At this time, if the background is bright, the background image is captured stronger than the target cylindrical article, and the image of the cylindrical article can only be captured lightly. Therefore, it is not preferable as a condition for capturing the color arrangement code attached to the surface of the cylindrical article.

  Therefore, in the present embodiment, the color arrangement code can be reliably captured by providing a cover for the purpose of shielding light in the upward direction in which the cylindrical article moves while rolling.

Third, when a plurality of cylindrical articles move while rolling continuously When a plurality of cylindrical articles move while rolling continuously, if the exposure time is too long for the moving speed, the cylindrical articles that move back and forth There is a risk that the color arrangement codes of the two will be picked up and interfere with decoding. In addition, when the front and rear cords are the same, the number of target cylindrical articles may be unclear. If it demonstrates concretely using FIG. 5, FIG. 5 is explanatory drawing explaining the mode of a capture in case the four cylindrical articles of P, Q, R, and S are rolling continuously. 0 in FIG. 5 is an explanatory diagram of the rotational phase and the decodable phase of each cylindrical article. When the rotational phase comes to this decodable phase, it can be normally captured and decoded. Represents. In this case, since each cylindrical article P, Q, R, and S rolls apart, for example, in this FIG. 5, the color arrangement code is positioned in the phase that can be decoded in the cylindrical article P. Capture and decode normally. On the other hand, with respect to the cylindrical article Q, it is shown that the color arrangement code enters the phase that can be decoded twice in terms of timing. In this case, it may be determined that there are two cylindrical articles. Further, in the same manner as the cylindrical article P, the cylindrical article R captures the color arrangement code at a decodable phase and performs decoding. As is apparent from this figure, the cylindrical articles P and Q have the same diameter, but the cylindrical article R has a large diameter D. On the other hand, the cylindrical article S is a cylindrical article having a large diameter D like the cylindrical article R. In this case, the timing does not match, and the capture is performed at the timing when the color arrangement code faces the decodable phase. It will be understood that there is an overwriting without taking place. Accordingly, FIG. 5 shows that when the four cylindrical articles P, Q, R, and S are actually rolling, the cylindrical article S may be read over.

  On the other hand, if the distance between the cylindrical articles moving between the shutter openings is equal to or less than the cylindrical diameter (D), the images of the adjacent cylindrical articles do not overlap, and thus the above-described problem does not occur. . Therefore, in order to solve such a problem, in this embodiment, when there are a plurality of cylindrical articles that move while rolling, it is necessary that the moving speed V of the cylindrical articles satisfies the condition of Equation 1. Three features.

(Formula 1) V <D / f
(However, D is the diameter of the cylindrical article, f is the camera frame interval)
Here, the “frame interval” refers to a time interval between frames to be imaged. For example, f (frame interval) when imaged with a 30 fps camera is 1/30 sec.

  Up to this point, the color arrangement code has been described as an example of the mark to be read, but of course, other optical automatic recognition codes such as a barcode may be used. Moreover, it is not limited to the optical automatic recognition code, and may be OCR numbers and characters. The present invention can be applied to any mark as long as it is optically recognized from an image.

Fourth color arrangement code reader As a device that realizes the method for reading the color arrangement code attached to the surface of a cylindrical article that moves while rolling as described above, the conveyance having a rolling surface on which the cylindrical article rolls is possible. Preferably, the image forming means includes an image processing means for inputting image data obtained from the CCD camera or the like and outputting original data. Further, it is preferable that a display and a printing unit for displaying and outputting the original data obtained by decoding in the image processing unit are also provided. It is also preferable to provide a light shielding plate for preventing background reflection. An example of the apparatus in this case is shown in FIG. Furthermore, when there are a plurality of moving cylindrical articles, it is preferable that a speed adjusting means for adjusting the moving speed of each cylindrical article is also provided.

(1) Of these, the conveying means may be an apparatus such as a belt conveyor having an inclined rolling surface, or may be a floor surface simply having an inclined rolling surface. A part of the rolling surface of the conveying means is a transparent member such as a glass plate, and an imaging means such as a CCD camera is arranged on the opposite side of the rolling surface. Thereby, a cylindrical article can be imaged from the lower direction. A part of the rolling surface may not be a glass plate but a net-like one. Alternatively, a rail-shaped member may be arranged so that an image can be captured from between them.

(2) It is preferable that the field of view of the image pickup means be able to pick up an image of a range beyond the outer circumference of the largest diameter of the moving cylindrical articles. Thereby, even when there are a plurality of cylindrical articles having different diameters, the color arrangement code attached to the surface can be reliably imaged. In addition, when such a visual field is not used, the color arrangement code can be reliably imaged by attaching the color arrangement code to a plurality of locations of the cylindrical article.

(3) It is assumed that the speed adjusting means can adjust the moving speed of the cylindrical article so as to satisfy Equation 1 so that the images of the adjacent cylindrical articles do not overlap.

(Formula 1) V <D / f (where D is the diameter of the cylindrical article and f is the frame interval of the camera)
Here, the “frame interval” refers to a time interval between frames to be imaged. For example, f (frame interval) when imaged with a 30 fps camera is 1/30. As such speed adjusting means, means capable of automatically or manually adjusting the angle of the rolling surface 10 of the conveying means is preferable.

(4) As the image processing means, it is generally preferable to use a computer, and it is preferable to read (decode) the image data input from the imaging means by an image processing technique.

(5) Further, as described above, it is preferable that the CCD camera 14 can image only the portion of the cylindrical article 12 that is in contact with the rolling surface 10. For this purpose, as described above, it is also preferable to provide the light shielding plate 18. Moreover, it is also preferable to provide the illumination means 20 for illuminating only the part which contacts the rolling surface 10 of the cylindrical article 12 (see FIG. 6). Such an illuminating means 20 is preferably provided on the lower surface side of the rolling surface 10 and is configured to emit light in an oblique direction so that the surface of the cylindrical article 12 on the rolling surface 10 side is preferentially illuminated. Furthermore, as the illumination means, when the rolling surface 10 is constituted by a transparent member, the transparent member is constituted by a light guide member such as acrylic, and a light emitting device such as an LED is provided on the end surface thereof. Is also preferable. Such illumination means is used, for example, in a liquid crystal backlight of a computer display. In this way, if the cylindrical article 12 is irradiated with light through the transparent member constituting the rolling surface 10, only the portion in contact with the rolling surface 10 can be preferentially illuminated, and the color array code can be imaged more clearly. Expected to be able to do.

  Up to this point, the color arrangement code has been described as an example of the mark to be read, but of course, other optical automatic recognition codes such as a barcode may be used. Moreover, it is not limited to the optical automatic recognition code, and may be OCR numbers and characters. The present invention can be applied to any mark as long as it is optically recognized from an image.

DESCRIPTION OF SYMBOLS 10 Rolling surface 12 Cylindrical article 14 CCD camera 16 Color arrangement code 18 Light shielding plate 20 Illumination means A Position where color arrangement code appears B Position where color arrangement code appears C Position where color arrangement code appears

Claims (13)

In a method of reading a mark attached to the surface of a cylindrical article that moves while rolling on the upper surface of the rolling surface,
A method for reading a mark attached to the surface of the cylindrical article, comprising: an imaging step of imaging the mark by an imaging means installed on a lower surface side of the rolling surface. In the method of reading the mark of Claim 1,
All or part of the rolling surface is composed of a transparent member,
The imaging step is performed on the surface of the cylindrical article, wherein the mark attached to the surface of the cylindrical article moving on the transparent member is imaged from below the transparent member. To read the mark. In the method of reading the mark of Claim 1,
All or part of the rolling surface is composed of a net-like article,
In the imaging step, the mark attached to the surface of the cylindrical article moving on the net-like article is imaged from the lower side of the net-like article on the surface of the cylindrical article. How to read the attached mark. The mark reading method according to claim 1,
All or part of the rolling surface is configured in a rail shape,
In the imaging step, the mark attached to the surface of the cylindrical article moving on the rail is imaged from below the rail, and the mark attached to the surface of the cylindrical article How to read. In the mark automatic reading method according to any one of claims 1 to 4,
A method for reading a mark attached to a surface of a cylindrical article, characterized in that a light shielding plate for preventing reflection of a background is arranged above the cylindrical article moving on the rolling surface. In the mark automatic reading method according to any one of claims 1 to 5,
The mark attached to the surface of the cylindrical article, characterized by having a speed adjustment step for adjusting the moving speed of each cylindrical article to satisfy the following formula when there are a plurality of the cylindrical articles: How to read.
(Formula 1) V <D / f (where D is the diameter of the cylindrical article and f is the frame interval of the imaging means) In an apparatus for reading a mark attached to the surface of a cylindrical article that moves while rolling on the upper surface of the rolling surface,
Having imaging means for imaging a mark attached to the surface of the cylindrical article;
The apparatus for reading a mark attached to the surface of the cylindrical article, wherein the imaging means is arranged on a lower surface side of the rolling surface. In the apparatus which reads the mark of Claim 7,
An apparatus for reading marks attached to the surface of the cylindrical article, wherein all or part of the rolling surface is made of a transparent member. In the apparatus which reads the mark of Claim 7,
An apparatus for reading a mark attached to the surface of the cylindrical article, wherein all or part of the rolling surface is constituted by a net-like article. In the apparatus which reads the mark of Claim 7,
An apparatus for reading marks attached to the surface of the cylindrical article, wherein all or part of the rolling surface is formed in a rail shape. In the apparatus which reads the mark of any one of Claim 7 to 10,
An apparatus for reading a mark attached to the surface of the cylindrical article, further comprising a light shielding means for preventing reflection of a background. In the apparatus which reads the mark of any one of Claim 7 to 11,
When there are a plurality of the cylindrical articles before, the cylindrical articles are provided on the surface of the cylindrical articles, characterized by having speed adjusting means for adjusting the moving speed of each cylindrical article so as to satisfy the following formula: A device that reads marks.
(Formula 1) V <D / f (where D is the diameter of the cylindrical article and f is the frame interval of the imaging means) The mark reading device according to claim 12,
The speed adjusting means adjusts the moving speed of the cylindrical article so as to satisfy the following expression by adjusting the angle of the rolling surface in the conveying means. A device that reads the attached marks.
(Formula 1) V <D / f (where D is the diameter of the cylindrical article and f is the frame interval of the imaging means)

Images