CN117630009A - A method and device for detecting defects in inner frame paper - Google Patents

Abstract

The application discloses a method and a device for detecting defects of inner frame paper, wherein the method comprises the following steps: receiving images of the tobacco bale acquired on a tobacco bale track outside an outlet of the folding turret; determining an actual detection window in the image of the tobacco bale; extracting texture features in an actual detection window, and judging whether the tobacco packet has an inner frame paper defect or not based on the texture features; if the inner frame paper defects exist, the original machine removing mechanism is controlled to remove the tobacco packages with the inner frame paper defects. According to the method, the detection system is arranged on the tobacco bale track at the outer side of the outlet of the folding turret, so that the tail end detection is realized, the accuracy of the inner frame paper defect detection is improved, and the defect rate of products is reduced.

Description

A method and device for detecting defects in inner frame paper

Technical field

The present application relates to the technical field of cigarette detection, and more specifically, to an inner frame paper defect detection method and device.

Background technique

According to the process flow, the FOCKE350 hard box packaging machine mainly includes a cigarette supply and processing system, a lining paper supply system, an inner frame paper supply system, a trademark paper supply system, a cigarette wrapping forming system, etc. The inner frame paper involves cutting, separating, wrapping Packing movement, folding movement, transfer movement and other processes. Under the action of centrifugal force and friction, the inner frame paper may be missing, the inner frame paper may move downward, the inner control paper may be damaged, the inner frame paper may be skewed, etc., or even defective cigarette packs such as burrs on the cutting edges of the inner frame paper may appear. The inner frame paper is mainly used to position the lid of the clamshell hard box after it is formed. It is the appearance that consumers can directly perceive and is crucial to the maintenance of the cigarette brand image. Therefore, how to prevent cigarette packs with defects in the inner frame paper from flowing into the finished product warehouse is an important equipment , process, and quality work are an important topic.

In the existing technology, due to the compact structure of the FOCKE350 model and the closed nature of the electronic control system, the installation and program control of the inner frame paper monitoring device requires a huge workload. Therefore, the position and surface quality of the inner frame paper cannot be checked before the cigarette pack is formed. Instead of monitoring, in front of the inner frame paper positioner on the folding turret (at station 4 in Figure 1), two methods are used for detection: using a color mark sensor, through the reflection of the inner frame paper and lining paper The difference in light intensity is used to determine the presence or absence of the inner frame paper; visual imaging is used to detect the shape and position of the inner frame paper.

However, the above inspection only reduces the number of inner frame paper defects, mainly because the inner frame paper that has been tested before the inner frame paper positioner still needs to pass through the inner frame paper positioner, the rotary folder, and the second folding turret on the folding turret. The movable folding guide rail process and the second movable folding guide rail process determine the final position of the inner frame paper in the cigarette pack. Therefore, the above monitoring method is an intermediate monitoring, not an end monitoring. If problems such as loss or scratching of the inner frame paper occur during the operation of the equipment after the inner frame paper positioner, product quality can only be ensured by manually performing a large number of self-inspections in downstream processes, with poor accuracy and efficiency.

Contents of the invention

This application provides a method and device for detecting inner frame paper defects. The detection system is arranged on the cigarette pack track outside the outlet of the folding turret, which realizes end detection, improves the accuracy of inner frame paper defect detection, and reduces the cost of the product. defect rate.

This application provides a method for detecting defects in inner frame paper, including:

receiving images of cigarette packs collected on the cigarette pack track outside the outlet of the folding turret;

Determine the actual detection window in the image of the cigarette pack;

Extract texture features within the actual detection window, and determine whether there are inner frame paper defects in the cigarette pack based on the texture features;

If there is a defect in the inner frame paper, the original machine rejection mechanism is controlled to complete the rejection of the cigarette packs with defects in the inner frame paper.

Preferably, detection gaps are symmetrically provided on both sides of the cigarette pack track, and lighting devices and image acquisition equipment are respectively provided on both sides of the cigarette pack track. The image acquisition equipment faces the detection gap, and the connection between the lighting device and the detection gap is connected to the cigarette pack track. The included angle of the package track is an acute angle, so that on the image of the cigarette package, the projection of the side close to the detection gap of the lighting device has an included angle with the upper edge of the cigarette package;

The end of the cut inner frame paper is located in the middle of the top surface of the cigarette pack and tilts upward to form an arc segment. The end of the inner frame paper is located within the shooting range of the image acquisition device.

Preferably, judging whether there is an inner frame paper defect in the cigarette pack based on texture features specifically includes:

If no texture features are detected within the actual detection window of the images on both sides, it is determined that the cigarette pack has an inner-frame paper defect.

Preferably, before extracting the texture features within the actual detection window, the method further includes: converting the image into a grayscale image, and using guided filtering to perform filtering preprocessing on the grayscale image.

Preferably, an image of a cigarette pack confirmed to be normal is used as the image template.

This application also provides an inner frame paper defect detection device, including an image receiving module, a window determination module, a defect detection module and a control module;

The image receiving module is used to receive images of cigarette packs collected on the cigarette pack track between the folding turret and the gluing device;

The window determination module is used to determine the actual detection window in the image of the cigarette pack;

The defect detection module is used to extract texture features within the actual detection window and determine whether there are inner frame paper defects in the cigarette pack based on the texture features;

The control module is used to control the original machine rejection mechanism to complete the rejection of cigarette packs with inner frame paper defects when there are defects in the inner frame paper.

Preferably, detection gaps are symmetrically provided on both sides of the cigarette pack track, and image acquisition equipment of the lighting device is provided on both sides of the cigarette pack track. The image acquisition equipment faces the detection gap, and the connection between the lighting device and the detection gap is connected with the cigarette. The included angle of the package track is an acute angle, so that on the image of the cigarette package, the projection of the side close to the detection gap of the lighting device has an included angle with the upper edge of the cigarette package;

The end of the cut inner frame paper is located in the middle of the top surface of the cigarette pack and tilts upward to form an arc segment. The end of the inner frame paper is located within the shooting range of the image acquisition device.

Preferably, the defect detection module is used to determine that the cigarette pack has an inner-frame paper defect when no texture features are detected within the actual detection window of the images on both sides.

Preferably, the inner frame paper defect detection device also includes an image preprocessing module, which is used to convert the image into a grayscale image, and use guided filtering to perform filtering preprocessing on the grayscale image.

Preferably, the inner frame paper defect detection device further includes a template determination module, which is used to use an image of a cigarette pack confirmed to be normal as an image template.

Other features and advantages of the present application will become apparent from the following detailed description of exemplary embodiments of the present application with reference to the accompanying drawings.

Description of drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description, serve to explain the principles of the application.

Figure 1 is a schematic structural diagram of a folding turret;

Figure 2 is a schematic structural diagram of the inner frame paper defect detection system provided by this application;

Figure 3 is a schematic diagram of the detection gap of the cigarette pack track provided by this application;

Figure 4 is a flow chart of the inner frame paper defect detection method provided by this application;

Figure 5 is a schematic diagram of an image obtained based on the inner frame paper defect detection system shown in Figure 3;

Figures 6A-6D show examples of image templates and images with different inner frame paper defects;

Figure 7 is a structural diagram of the inner frame paper defect detection device provided by this application.

Detailed ways

Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of components and steps, numerical expressions, and numerical values set forth in these examples do not limit the scope of the present application unless otherwise specifically stated.

The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the application or its application or uses.

Techniques, methods and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the techniques, methods and devices should be considered a part of the specification.

In all examples shown and discussed herein, any specific values are to be construed as illustrative only and not as limiting. Accordingly, other examples of the exemplary embodiments may have different values.

This application provides a method and device for detecting inner frame paper defects. The detection system is arranged on the cigarette pack track outside the outlet of the folding turret, which realizes end detection, improves the accuracy of inner frame paper defect detection, and reduces product cost. defect rate. Moreover, in this application, the industrial computer automatically generates defect types and automatically counts and outputs the number of the same defect type, which facilitates equipment managers and repair personnel to understand the equipment.

As shown in Figures 2 and 3, the inner frame paper defect detection system of the present application is arranged on the cigarette pack track 200 outside the outlet of the folding turret 100 (station 7 in Figure 1), and is located in front of the glue application device. A cigarette pack drying and conveying mechanism 300 is also provided downstream of the cigarette pack track 200, and a waste box 400 is provided at the cigarette pack drying and conveying mechanism 300. On the cigarette pack track 200, each cigarette pack 500 is positioned by a push target 210. Detection gaps 220 are symmetrically provided on both sides of the cigarette pack track 200, and an in-position detection switch 30 is provided at the detection gap 220.

As an embodiment, the position detection switch 30 is an optical fiber sensor.

A lighting device 20 and an image acquisition device 10 are respectively provided on both sides of the cigarette package track 200 . The image acquisition device 10 faces the detection gap 220 . When the cigarette pack moves in the track and blocks the light of the in-position detection switch 30, the industrial computer controls the lighting device 20 and the image acquisition device 10 to cooperate to collect images and transmit them to the image processing unit of the industrial computer through the USB port. The angle between the line connecting the lighting device 20 and the detection notch 220 and the cigarette pack track 200 is an acute angle, so that in the image of the cigarette pack 500, the side (the right side in Figure 3) close to the detection notch 220 of the lighting device 20 The projection 610 has an included angle with the upper edge of the cigarette pack 600, as shown in Figure 5. Therefore, in the image, the top surface of the cigarette pack forms straight line AB, and one of the projected edge lines forms straight line CD, and the intersection point of the two is J. In Figure 5, the right side of the cigarette pack is the folded corner portion (i.e., the opening portion) 620, and the left side is the bottom of the cigarette pack.

When the cigarette pack 500 is located on the cigarette pack track 200, the end of the cut inner frame paper is located on the middle of the top surface of the cigarette pack 500 and tilts upward to form an arc segment, and the end of the inner frame paper is located within the shooting range of the image acquisition device. . Therefore, as shown in Figure 5, in the image, the top surface of the cigarette pack 600 has an arc segment in the middle, and the highest point of the arc segment is Q.

Based on the above, as shown in Figure 4, the inner frame paper defect detection method provided by this application includes:

S410: Receive images of cigarette packs collected on the cigarette pack track outside the outlet of the folding turret.

S420: Determine the actual detection window in the image of the cigarette pack.

As an embodiment, based on the above inner frame paper defect detection system, the actual detection window in the image of the cigarette pack is determined, specifically including:

S4201: Identify the first straight line corresponding to the top edge of the cigarette pack in the measured image and the second straight line corresponding to the projection, and use the intersection of the first straight line and the second straight line as the first intersection point J1 (x1, y1); and Identify the third straight line corresponding to the top edge of the cigarette pack in the image template and the fourth straight line corresponding to the projection, and use the intersection of the third straight line and the fourth straight line as the second intersection point J0 (x0, y0).

As an example, an image of a cigarette pack confirmed to be normal is used as an image template, as shown in Figure 6A.

If the first intersection point is not detected in the images on both sides of the cigarette pack, it is determined that the cigarette pack has no inner frame paper defect. Possible reasons are the original equipment receiving a blank, the replacement of the aluminum foil paper tray, the replacement of the inner frame paper tray, etc. Cigarette packs without inner frame paper and trademark paper that appear during the signal.

S4202: Determine the floating vector V=J1-J0=(x1-x0, y1-y0) based on the coordinates of the first intersection point J1 and the coordinates of the second intersection point J0.

S4203: Move the standard detection window according to the floating vector V (its coordinates are the coordinates of the detection window in the image template), and obtain the coordinates of the actual detection window corresponding to the measured image to eliminate the impact of position changes caused by the jitter of the cigarette pack on the image. .

S430: Extract texture features within the actual detection window, and determine whether there are inner frame paper defects in the cigarette pack based on the texture features.

As an embodiment, texture features within the actual detection window are extracted based on the LAWS texture extraction algorithm.

Preferably, before extracting the texture features within the actual detection window, the method further includes: converting the image into a grayscale image, and using guided filtering to perform filtering preprocessing on the grayscale image.

As an example, determining whether there is an inner frame paper defect in a cigarette pack based on texture features includes:

Q1: Determine whether there are texture defects in the actual detection window based on the Support Vector Machines (SVM) classification algorithm.

Q2: If the area of texture defects identified on one or both sides of the cigarette pack exceeds the first threshold, it is determined that the inner frame paper of the cigarette pack is damaged or has indentations on the surface. If the area of the texture defect identified on one or both sides of the cigarette pack exceeds the second threshold (greater than the first threshold), it is determined that the cigarette pack does not have inner frame paper, as shown in the example in Figure 6D. If the areas of texture defects on the inner frame paper on both sides of the cigarette pack are within the first threshold, perform Q3.

Q3: Detect the highest point Q(x,y) of the arc segment in the actual detection window based on the corner point matching algorithm. If the ordinate y of the highest point is less than the lower limit ordinate value of skew or greater than the upper limit ordinate value of skew, it is determined that the inner frame paper has a skew defect, as shown in the example in Figure 6C. If the ordinate y of the highest point is equal to the ordinate of the first intersection J1, and the abscissa x of the highest point is greater than the maximum abscissa of downward movement (for example, 1mm). If the inner frame paper moves downward (the abscissa will shift toward the folding angle), it is determined that the cigarette pack has a defect of the inner frame paper moving downward, as shown in the example in Figure 6B. If the ordinate y of the highest point is greater than or equal to the ordinate value of the first intersection point J1, and the abscissa of the highest point is less than the maximum abscissa of the downward movement, perform Q4.

Q4: Identify whether there is a protruding part on the cutting edge of the inner frame paper in the measured image. If so, determine whether there is a burr on the cutting edge. If the burr area on the left or right side of the cigarette pack exceeds the set value, it is determined that the cigarette pack has an excessive burr defect in the inner frame paper. Otherwise, the cigarette pack is a normal cigarette pack.

As an embodiment, a Blob (Binary large object) analysis algorithm is used to identify burrs.

S440: If there is a defect in the inner frame paper, control the original machine rejection mechanism to complete the rejection of the cigarette packs with inner frame paper defects.

It should be noted that the above-mentioned paper without inner frame, inner frame paper with damage or indentation on the surface, inner frame paper with skew defects, inner frame paper with downward movement defects, inner frame paper with excessive burrs, etc. are all inner frame paper defects.

Specifically, when the industrial computer determines that there is a defect in the inner frame paper of the cigarette package, it calls the shift register forming: it receives the high-level signal from the optical fiber sensor, and when it accumulates from 0 to 5, the industrial computer outputs the high-level signal to the FOCKE350 elimination port. The solenoid valve activates the original machine's removal mechanism to remove defective cigarette packets.

Based on the above, this application provides an inner frame paper defect detection device. As shown in FIG. 7 , the inner frame paper defect detection device includes an image receiving module 710 , a window determination module 720 , a defect detection module 730 and a control module 740 .

The image receiving module 710 is used to receive images of cigarette packs collected on the cigarette pack track between the folding turret and the gluing device.

The window determination module 720 is used to determine the actual detection window in the image of the cigarette pack.

The defect detection module 730 is used to extract texture features within the actual detection window, and determine whether there is an inner frame paper defect in the cigarette pack based on the texture features.

The control module 740 is used to control the original machine rejection mechanism to complete the rejection of cigarette packs with inner frame paper defects when there are inner frame paper defects.

Preferably, detection gaps are symmetrically provided on both sides of the cigarette pack track, and image acquisition equipment of the lighting device is provided on both sides of the cigarette pack track. The image acquisition equipment faces the detection gap, and the connection between the lighting device and the detection gap is connected with the cigarette. The included angle of the package track is an acute angle, so that on the image of the cigarette package, the projection of the side close to the detection gap of the lighting device has an included angle with the upper edge of the cigarette package.

The end of the cut inner frame paper is located in the middle of the top surface of the cigarette pack and tilts upward to form an arc segment. The end of the inner frame paper is located within the shooting range of the image acquisition device.

Preferably, the inner frame paper defect detection device also includes an image preprocessing module 750. The image preprocessing module 750 is used to convert the image into a grayscale image, and use guided filtering to perform filtering preprocessing on the grayscale image.

Preferably, the inner frame paper defect detection device further includes a template determination module 760, which is used to use an image of a cigarette pack confirmed to be normal as an image template.

Preferably, the defect detection module 730 includes a texture defect identification module 7301 and a determination module 7302. The texture defect identification module 7301 is used to determine whether there are texture defects in the actual detection window based on the SVM classification algorithm. The determination module 7302 is used to determine whether there is an inner frame paper in the cigarette pack and whether there is damage or surface indentation in the inner frame paper based on the area of the texture defect.

Preferably, the defect detection module 730 also includes a highest point detection module 7303, which is used to detect the highest point of the arc segment in the actual detection window based on the corner point matching algorithm. The determination module 7302 is used to determine whether there is a downward movement or skew defect in the inner frame paper of the cigarette pack based on the coordinates of the highest point.

Preferably, the defect detection module 730 also includes a burr identification module 7304, which is used to identify whether there are protruding parts on the cutting edge of the inner frame paper in the measured image. The determination module 7302 is used to determine whether the inner frame paper of the cigarette pack has excessive burr defects based on the burr area.

Although some specific embodiments of the present application have been described in detail through examples, those skilled in the art should understand that the above examples are for illustration only and are not intended to limit the scope of the present application. Those skilled in the art will understand that the above embodiments can be modified without departing from the scope and spirit of the application. The scope of the application is defined by the appended claims.

Claims (10)

1. A method for detecting defects in inner frame paper, which is characterized by including: receiving images of cigarette packs collected on the cigarette pack track outside the outlet of the folding turret; Determine the actual detection window in the image of the cigarette pack; Extract texture features within the actual detection window, and determine whether there is an inner frame paper defect in the cigarette pack based on the texture features; If there is a defect in the inner frame paper, the original machine rejection mechanism is controlled to complete the rejection of the cigarette packs with defects in the inner frame paper. 2. The inner frame paper defect detection method according to claim 1, characterized in that detection gaps are symmetrically provided on both sides of the cigarette pack track, and lighting devices and images are respectively provided on both sides of the cigarette pack track. Acquisition equipment, the image acquisition equipment is facing the detection gap, and the angle between the connection line of the lighting device and the detection gap and the cigarette pack track is an acute angle, so that the image of the cigarette pack is close to the The projection of the side of the detection notch of the lighting device has an angle with the upper edge of the cigarette pack; The end of the cut inner frame paper is located in the middle of the top surface of the cigarette pack and tilts upward to form an arc segment. The end of the inner frame paper is located within the shooting range of the image acquisition device. 3. The inner frame paper defect detection method according to claim 1, characterized in that judging whether the cigarette pack has an inner frame paper defect based on the texture characteristics specifically includes: If no texture features are detected in the actual detection window of the images on both sides, it is determined that the cigarette pack has an inner-frame paper defect. 4. The inner frame paper defect detection method according to claim 1, characterized in that, before extracting the texture features in the actual detection window, it further includes: converting the image into a grayscale image, and using guided filtering to The grayscale image is preprocessed by filtering. 5. The inner frame paper defect detection method according to claim 3, characterized in that an image of a cigarette pack confirmed to be normal is used as an image template. 6. An inner frame paper defect detection device, characterized in that it includes an image receiving module, a window determination module, a defect detection module and a control module; The image receiving module is used to receive images of cigarette packs collected on the cigarette pack track between the folding turret and the gluing device; The window determination module is used to determine the actual detection window in the image of the cigarette pack; The defect detection module is used to extract texture features within the actual detection window, and determine whether there is an inner frame paper defect in the cigarette pack based on the texture features; The control module is used to control the original machine rejection mechanism to remove cigarette packets with inner frame paper defects when there are defects in the inner frame paper. 7. The inner frame paper defect detection device according to claim 6, characterized in that detection gaps are symmetrically provided on both sides of the cigarette pack track, and images of lighting devices are respectively provided on both sides of the cigarette pack track. Acquisition equipment, the image acquisition equipment is facing the detection gap, and the angle between the connection line of the lighting device and the detection gap and the cigarette pack track is an acute angle, so that the image of the cigarette pack is close to the The projection of the side of the detection notch of the lighting device has an angle with the upper edge of the cigarette pack; The end of the cut inner frame paper is located in the middle of the top surface of the cigarette pack and tilts upward to form an arc segment. The end of the inner frame paper is located within the shooting range of the image acquisition device. 8. The inner frame paper defect detection device according to claim 6, characterized in that the defect detection module is used to determine that the cigarette pack is not detected in the actual detection window of the image on both sides when texture features are not detected. There is a paper defect without inner frame. 9. The inner frame paper defect detection device according to claim 6, further comprising an image pre-processing module, the image pre-processing module is used to convert the image into a grayscale image and use guided filtering to The grayscale image is subjected to filtering preprocessing. 10. The inner frame paper defect detection device according to claim 8, further comprising a template determination module, the template determination module being used to use an image of a cigarette pack confirmed to be normal as an image template.