JP2008151720A - Cylinder appearance inspecting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cylinder appearance inspecting method for accurately inspecting a cylinder without a rotation. <P>SOLUTION: A lateral image of a workpiece as a reference is cylindrically developed. A conversion image having a curved portion flatly developed is acquired. The conversion images are acquired and combined over the entire circumference by repeating rotations of the workpiece and acquisitions of the conversion image. A reference image is formed over the entire circumference of the workpiece. A front development image is generated by cylindrically developing a front portion of the displayed workpiece image on the lateral image of the workpiece to be inspected (S3). The front development image and the reference image are pattern-matched (S4). The workpiece is inspected based on the degree of matching (S5). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cylindrical body appearance inspection method for inspecting a cylindrical body by image processing.

  Conventionally, printing has been performed on the side surface of can juice or the like, and it is configured to be able to perform different product inspection, upside down inspection, and foreign matter inspection by inspecting the printed state.

  When inspecting the appearance of such a cylindrical body, when the cylindrical body is imaged from the side surface, an image near the center with less distortion is bonded and synthesized to create a reference image of the entire circumference of the cylindrical body side surface.

  At the time of inspection, the inspection object is imaged with a camera, and a portion with less distortion near the center of the cylindrical body is pattern-matched with the reference image to perform different product inspection, upside down inspection, and the like.

  As another method, there is a method of acquiring an image without distortion by imaging with a line sensor camera while rotating a cylindrical body.

  However, in such an inspection method, in the former inspection method in which the image near the center of the cylindrical body is pasted, distortion remains in the side image of the cylindrical body, and thus it was difficult to perform an accurate inspection. .

  In the latter inspection method using a line sensor camera, a mechanical structure for rotating the cylindrical body is required, which is expensive and takes time for inspection.

  The present invention has been made in view of such a conventional problem, and an object thereof is to provide a cylindrical body appearance inspection method capable of performing a more accurate inspection without rotating the cylindrical body. It is.

  In order to solve the above-mentioned problem, in the cylindrical body appearance inspection method according to claim 1 of the present invention, in the cylindrical body appearance inspection method for inspecting the appearance of the cylindrical body, a side image of the reference cylindrical body is developed in a cylinder. A step of acquiring a converted image in which the curved surface portion is flattened and rotating the cylindrical body a plurality of times, and a reference image acquisition step of acquiring a composite image of the entire circumference of the cylindrical body as a reference image; A cylindrical development of the side image of the cylindrical body to obtain a cylindrical development image, pattern matching the cylindrical development image with the reference image, and an inspection step of performing inspection based on the result.

  That is, before the inspection is started, a converted image in which the curved surface portion is flattened is acquired by cylindrically developing the side surface image of the cylindrical body serving as a reference. Then, by repeating this process a plurality of times by rotating the cylindrical body, a combined image of the entire circumference of the cylindrical body is acquired as a reference image. As a result, the reference image serving as a comparison reference during the inspection can be obtained without using a line sensor camera.

  Further, at the time of inspection, a cylindrical developed image is acquired by expanding a side image of a cylindrical body to be inspected. And this cylindrical expansion image is pattern-matched with the said reference image, the result is acquired, and a test | inspection is performed based on the matching etc. at this time.

  In the cylindrical body appearance inspection method according to the second aspect, the illumination means for illuminating the cylindrical body is configured by illumination having a groove-shaped light emitting portion in which the central portion is immersed.

  That is, the illumination for illuminating the cylindrical body has a groove-shaped light emitting portion with a central portion immersed therein. The recessed part is also illuminated by the illumination.

  As described above, in the cylindrical body appearance inspection method according to the first aspect of the present invention, it is possible to obtain a reference image without distortion, which serves as a comparison reference at the time of inspection, without using an expensive line sensor camera.

  Also, at the time of inspection, a cylindrical development image without distortion can be obtained by cylindrical development of a side image of a cylindrical body to be inspected. Thereby, a more accurate inspection can be performed.

  And, since this cylindrical development image is pattern-matched with the reference image, and the inspection is performed based on the result, the mechanical structure for rotating the cylindrical body to be inspected is compared with the case of using a line sensor camera. This eliminates the need for cost reduction and also reduces the inspection time.

  Therefore, more accurate inspection can be performed at high speed without rotating the cylindrical body.

  Further, in the cylindrical body appearance inspection method according to claim 2, the illumination for illuminating the cylindrical body includes a groove-shaped light emitting portion with a central portion immersed therein, and the cylindrical body is illuminated with illumination having a flat light emitting portion. Compared with the case, the part which wraps around from the front to the side can be illuminated uniformly by the illumination.

  Thereby, the image of a wraparound part can also be acquired clearly.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a view showing a cylindrical appearance inspection apparatus 1 for carrying out the cylindrical appearance inspection method according to the present embodiment. The cylindrical appearance inspection apparatus 1 is an apparatus that performs an appearance inspection of a cylindrical body such as can juice, specifically, an image of a printed portion on a side surface to perform different kind inspection, upside down inspection, and foreign matter inspection. It is installed in the factory transport line.

  That is, illumination means for irradiating light to the work 11 to be inspected passing through a predetermined position is provided on the side of the conveyor 12 on which the work 11 as a cylindrical body is conveyed. As shown also in (b), it is comprised by the main illumination 13 which illuminates the said workpiece | work 11 from a side, and the auxiliary illumination 14 which illuminates the said workpiece | work 11 from right above.

  The main illumination 13 is composed of a reflector 21 provided on the side of the work 11 conveyed on the conveyor 12 and a pair of lamps 22, 22 provided along the reflector 21. Yes. As shown in FIG. 2, the reflection plate 21 is composed of a bottom surface portion 23 formed of a curved surface and upright portions 24 and 24 erected on both side edges of the bottom surface portion 23 and opened upward. It has a U-shaped cross section.

  Accordingly, as shown in FIG. 1A, the reflecting plate 21 is configured to reflect the light 31 and 31 from the lamps 22 and 22 provided on the upper surface thereof on the inner surface thereof. In addition, as shown in FIG. 2, the inner surface of the reflecting plate 21 constitutes a groove-shaped light emitting portion 32 in which the central portion is immersed. At this time, the light reflected by the bottom surface portion 23 is configured to illuminate the front surface of the workpiece 11, and the light 31 and 31 reflected by the left and right standing portions 24 and 24 are shown in FIG. As shown, it is configured so as to illuminate the portion of the workpiece 11 that wraps around from the front.

  As shown in FIG. 1B, a camera 41 is provided obliquely above the front side of the main illumination 13 so that an image of the side surface of the workpiece 11 conveyed by the conveyor 12 can be acquired. It is configured as follows. The camera 41 is connected to a control unit 42 configured by a computer device, and the control unit 42 operates according to a program stored in a storage unit, so that the side surface of the workpiece 11 input from the camera 41 is detected. The image is analyzed and the work 11 is inspected.

  In the present embodiment configured as described above, when the workpiece 11 is inspected, in the previous stage, the camera 41 acquires a side image from the side surface of the workpiece 11 as a reference cylindrical body, By converting the front part of the workpiece in the side image and converting it into a cylinder, a converted image in which the curved part is developed flat is acquired.

  Then, the converted image of the peripheral surface of the workpiece 11 is repeated a plurality of times by the rotation step of rotating the workpiece 11 about a predetermined angle about the axis and the conversion step of acquiring the side image and converting it to the converted image. Is acquired over the entire circumference, and then the converted images are combined to form a reference image in which the peripheral surface of the work 11 is developed over the entire circumference.

  As a result, the reference image without distortion, which becomes a comparison reference at the time of inspection, is acquired without using an expensive line sensor camera, and the reference image is stored in the control unit 42.

  Next, the operation of the control unit 42 of the cylindrical appearance inspection apparatus 1 when inspecting the workpiece 11 conveyed by the conveyor 12 will be described according to the flowchart shown in FIG.

  That is, when an image from the side surface of the workpiece 11 passing through a predetermined position is captured by the camera 41, the captured side image is input from the camera 41 (S1), and the position of the workpiece 11 is determined from the side image. Is obtained (S2). At this time, as shown in FIG. 4, the control unit 42 displays the side image 52 on the screen 51 of the connected monitor.

  The front portion of the workpiece image 61 of the workpiece 11 displayed in the side image 52 is coordinate-transformed and developed into a cylinder, whereby a front development image 63 as a cylindrical development image in which the curved surface portion 62 is developed flat. Is generated (S3). Thereby, the said front expansion | deployment image 63 from which cylindrical distortion was removed in the 90 degree or more range of the said workpiece | work 11 is acquirable.

  The front development image 63 acquired in this way is displayed on the screen 51 of the monitor, and the matching area 71 to which the front development image 63 matches is extracted from the reference image 64 displayed on the screen 51, and the reference The matching area 71 of the image 64 and the front development image 63 are pattern-matched (S4).

  In pattern matching between the front developed image 63 and the reference image 64, the workpiece 11 to be inspected is the reference workpiece 11 indicated by the reference image 64 based on the degree of matching, the presence or absence of a portion having a large density difference, and the like. It is inspected whether it is the same type, whether the printing direction of the peripheral surface is correct, whether there is any mixing of different workpieces 11 (S5). As a result, if it is normal, a message indicating normality is displayed on the monitor (S6), and the process returns to the main routine. On the other hand, if it is abnormal, a message indicating that the monitor is abnormal is displayed. By removing from the conveyor 12 on the downstream side (S7), the process returns to the main routine.

  As described above, in the present embodiment, the side image of the workpiece 11 serving as a reference and the side image 52 of the workpiece 11 to be inspected are developed in a cylinder, so that the reference image 64 and the front development without distortion are developed. An image 63 can be acquired. Thereby, a more accurate inspection can be performed.

  Then, since the front developed image 63 is pattern-matched with the reference image 64 and inspection is performed based on the result, the work 11 to be inspected is rotated at the time of inspection as compared with the case of using a line sensor camera. The mechanical structure is not required, so that the cost can be reduced and the inspection time can be shortened.

  Therefore, it is possible to perform a more accurate inspection at a high speed without rotating the workpiece 11 and to perform an inspection in the process of conveying the workpiece 11 by the conveyor 12.

  On the other hand, the main illumination 13 for illuminating the workpiece 11 to be inspected includes a reflecting plate 21 having a U-shaped cross section, and the reflecting plate 21 forms a groove-shaped light emitting portion 32 in which the central portion is immersed. Yes. For this reason, compared with the case where the said workpiece | work 11 is illuminated with the illumination provided with the flat light emission part, the part which went around to the side from the workpiece | work 11 front can also be illuminated uniformly by the said main illumination 13. FIG.

  Thereby, the image of a wraparound part can also be acquired clearly and an exact test | inspection can be implemented.

  In the present embodiment, the case where the groove-shaped light emitting portion 32 in which the central portion is immersed is configured using the reflecting plate 21 having a U-shaped cross section is described as an example, but the present invention is not limited thereto. Instead, for example, by using a surface light emitter having a U-shaped cross section, the groove-shaped light-emitting portion 32 in which the central portion is immersed may be configured.

  Moreover, the shape is not limited to a U-shaped cross section, and may be a V-shaped cross section, for example.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows one embodiment of this invention, (a) is a top view, (b) is a side view. It is a perspective view which shows the reflecting plate of the embodiment. It is a flowchart which shows the operation | movement of the embodiment. It is a figure which shows the example of a display of the screen of the embodiment.

Explanation of symbols

1 Cylindrical appearance inspection device 11 Workpiece (cylindrical body)
13 Main Illumination 21 Reflector 32 Light Emitting Unit 41 Camera 42 Control Unit 52 Side Image 62 Curved Surface Part 63 Front Deploy Image (Cylinder Develop Image)
64 reference image

Claims (2)

In the cylindrical body appearance inspection method for inspecting the appearance of the cylindrical body,
The process of acquiring a side image of a reference cylindrical body as a converted image in which a curved surface portion is flattened by developing the cylinder is repeated a plurality of times by rotating the cylindrical body, and a composite image of the entire circumference of the cylindrical body is used as a reference. A reference image acquisition step to acquire as an image;
A cylindrical development of a side image of a cylindrical body to be inspected to obtain a cylindrical development image, pattern-matching the cylindrical development image with the reference image, and performing an inspection based on the results;
A cylindrical body appearance inspection method comprising: 2. The cylindrical body appearance inspection method according to claim 1, wherein the illuminating means for illuminating the cylindrical body is configured by illumination having a groove-shaped light emitting portion in which a central portion is immersed.

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