Method and apparatus for evaluating the quality of a package closure

Abstract

A method 1600 for quality assessment of a sealed portion 414 of a package 100, the package 100 including at least a tough layer 406 a, 406 b and a plastic layer 408 a, 408 b. The sealed portion 414 is formed by holding a first portion 402 a and a second portion 402 b of the package 100 together while applying heat to melt the plastic layers 408 a, 408 b of the first and second portions 402 a, 402 b and thereby adhere the first and second portions 402 a, 402 b to one another. The method (1600) includes capturing (1602) image data depicting an occluded portion (414) using a camera (814), identifying (1604) reference lines (1204, 1304, 1404, 1504) in the image data, identifying (1606) occluded portion boundary lines (1202, 1302, 1402, 1502) in the image data, determining (1608) a occluded portion evaluation feature set based on the reference lines (1204, 1304, 1404, 1504) and the occluded portion boundary lines (1202, 1302, 1402, 1502), and comparing (1610) the occluded portion evaluation feature set to a reference feature set.

Description

[Technical field]

[0001] This patent application relates generally to the field of packaging. More particularly, this patent application relates to the quality assessment of closures in packages, for example for food products. [Background technology]

[0002] Carton-based packages for milk and other food products are well known and recognized in many parts of the world. One example is the block-shaped package Tetra Brik™ marketed by Tetra Pak. This package is produced in so-called roll-fed packaging machines. The general principle of this type of machine is to form a tube of packaging material, fill the tube with the food product and form the package from the bottom end of the tube. These steps are carried out continuously, so the advantage is that speeds of more than 30,000 packages per hour can be achieved. Another type of packaging machine for producing packages for food products is the so-called blank-fed packaging machine. In this type of machine, the packaging material is provided in the form of blanks, i.e. sleeve-shaped and pre-cut pieces of packaging material, which are filled and formed into packages one by one.

[0003] In both types of packaging machines, a top and a bottom are formed for each package by sealing two pieces of packaging material together. Different sealing techniques, also known as welding techniques, are available today. Induction heating sealing technique can be used for packaging materials that include an aluminum layer. The general principle of this technique is to induce an electric current in the packaging material so that heat is generated. The heat then melts the outer plastic layers in the packaging material so that they can adhere to each other when they are held against each other. Another example of a sealing technique that can be used is ultrasonic sealing technique. Instead of inducing an electric current, this technique uses ultrasonic waves to generate heat.

[0004] Regardless of which sealing technique is used, seals are formed in the package. These seals not only ensure that the package does not leak, but also, specifically for sterile packages, that unwanted microorganisms cannot get into the package. Today, there are different methods for the quality assessment of seals. A direct method is that an operator looks at the produced package at regular intervals to detect possible deviations caused by an insufficient seal. An example of an indirect method used to detect an insufficient seal is to close the package while applying pressure to the sides so that an inwardly bulging side is formed on the package. If the seal is insufficient, the sides no longer bulge inwards due to air leaking into the package. This, in turn, makes it possible to easily identify packages that may have an insufficient seal.

[0005] Although both direct and indirect techniques for detecting poor closures in packages are available today, improvements are needed to further reduce the time and effort required to identify packages with poor closures. Summary of the Invention [Problem to be solved by the invention]

[0006] It is an object of the present invention to at least partially overcome one or more of the above-identified limitations of the prior art, in particular to provide an apparatus and method that allows for easy and cost-effective identification of poor seals. [Means for solving the problem]

[0007] According to a first aspect, there is provided a method for quality assessment of a sealed portion of a package, the package including at least a rigid layer and a plastic layer, the sealed portion being formed by holding a first portion and a second portion of the package against each other while providing heat to melt the plastic layers of the first and second portions and thereby adhere the first and second portions to each other, the method comprising: capturing image data depicting the sealed portion using a camera; identifying a reference line in the image data; identifying a sealed portion boundary line in the image data; determining a sealed portion evaluation feature set based on the reference line and the sealed portion boundary line; and comparing the sealed portion evaluation feature set to a reference feature set.

[0008] The occlusion evaluation feature set may include at least one distance measure between the reference line and the occlusion boundary.

[0009] The method may further include determining an occlusion evaluation area defined by the reference line and an occlusion boundary line, the occlusion evaluation feature set including the occlusion evaluation area.

[0010] The method may further include determining a boundary line deviation measure by comparing the enclosed portion boundary to an ideal enclosed portion boundary, the at least one enclosed portion evaluation feature set including a first boundary line deviation measure.

[0011] The method may further include determining a baseline deviation measure by comparing the baseline to an ideal baseline, the closure sub-assessment feature set including the baseline deviation measure.

[0012] The method may further include identifying a peripheral non-sealed portion having an open end facing the sealed portion boundary line, and determining a depth of the peripheral non-sealed portion by determining a minimum distance between the peripheral non-sealed portion and the reference line, wherein the set of at least one sealed portion evaluation features includes a depth of the peripheral non-sealed portion.

[0013] The method may further include identifying an internal non-enclosed portion within the enclosed portion and determining an area of ​​the internal non-enclosed portion, wherein the enclosed portion evaluation feature set includes the area of ​​the internal non-enclosed portion.

[0014] The seal portion evaluation feature set may further include the input seal energy.

[0015] The reference line may depict a ridge press fit of the sealing portion.

[0016] Alternatively, the reference lines may delineate cutting lines.

[0017] According to a second aspect, an apparatus for quality assessment of a sealed portion of a package, the package including at least a rigid layer and a plastic layer, the sealed portion being formed by holding a first portion and a second portion of the package against each other while providing heat to melt the plastic layers of the first and second portions and thereby adhere the first and second portions to each other, the apparatus including a camera configured to capture image data depicting the sealed portion, a processing device configured to identify a reference line in the image data, the reference line depicting a ridge press-in portion of the sealed portion, identify a sealed portion boundary line in the image data, determine a sealed portion evaluation feature set based on the reference line and the sealed portion boundary line, and compare the sealed portion evaluation feature set to the reference feature set.

[0018] The occluded portion assessment feature set may include at least one distance measure between the reference line and the occluded portion boundary.

[0019] The reference line may depict a ridge press fit of the sealing portion.

[0020] The processing device may be further configured to determine an occluded portion evaluation area defined by the reference line and the occluded portion boundary, the occluded portion evaluation feature set comprising the occluded portion evaluation area.

[0021] According to a third aspect, there is provided a computer program product comprising instructions which, when executed on a computer, cause the computer to carry out the method according to the second aspect. The step of capturing image data may be a step of reading the image data from an image sensor such as a CMOS or CCD. Alternatively, the image data may be received from an external camera from the device running the computer program.

[0022] Further objects, features, aspects and advantages of the present invention will become apparent from the following detailed description and drawings.

[0023] Embodiments will now be described, by way of example, with reference to the accompanying schematic drawings. [Brief description of the drawings]

[0024] [Figure 1a] FIG. [Figure 1b] 1 generally illustrates a piece of packaging material that can be formed into the package shown in FIG. 1a. [Diagram 2] 1 illustrates generally a roll-fed packaging machine. [Diagram 3] FIG. 1 is a cross-sectional view of an example packaging machine. [Figure 4] 1 shows generally the lower part of the package shown in FIG. 1a. [Diagram 5] 1 shows an example of a cross-sectional view of a sealing portion. [Figure 6] 13 shows another example of a cross-sectional view of a sealing portion. [Figure 7] 1 shows an example of a front view of a sealing portion. [Figure 8a-c] An apparatus for seal quality assessment is generally shown by way of example. [Figure 9a-9b] Two other examples of devices are generally shown. [Figure 10] An embodiment of the device is shown as an example. [Figure 11a-b] Another embodiment is given by way of example. [Figure 12] FIG. 13 is a cross-sectional view of a sealing portion. [Figure 13] 13 is another example of a cross-sectional view of a sealing portion. [Figure 14] 13 is another example of a cross-sectional view of a sealing portion. [Figure 15] 13 is yet another example of a cross-sectional view of a sealing portion. [Figure 16] 1 is a flow chart illustrating method steps for seal quality assessment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Figure 1a generally illustrates one example of a carton package 100 made from the pieces of packaging material shown in Figure 1b. The carton package 100 includes multiple panels separated from one another by lines of weakness that ensure that the pieces of packaging material can be efficiently folded into the package 100 by a packaging machine, also known as a filling machine.

[0026] In this example, the package 100 comprises a first back panel 102, a left panel 104, a front panel 106, a right panel 108 and a second back panel 110, which together form a sleeve-shaped body of the package 100. The first and second back panels 102, 110 are attached to each other by a so-called longitudinal seal. To avoid the product held in the package coming into contact with an inner layer of packaging material, the periphery of the second back panel 110, which is placed inside the periphery of the first back panel 102, may be protected by a plastic strip, sometimes called a longitudinal seal strip.

[0027] The package 100 further includes a first upper back panel 112, a left corner top panel 114, an upper front panel 116, a right corner panel 118, and a second upper back panel 120, which together form the top surface of the package 100. In a similar manner to the first and second back panels 102, 110, the first and second back top panels 112, 120 are attached to one another. To close the package 100, the first and second back top panels 112, 120 are attached to the upper front panel 116, two portions of the left corner top panel 114 are attached to one another, and two portions of the right corner top panel 118 are attached to one another. This is provided by a lateral seal that is performed in the packaging machine after the package is filled with product.

[0028] The package 100 also includes a first bottom back panel 122, a left corner bottom panel 124, a bottom front panel 126, a right corner bottom panel 128, and a second bottom back panel 130, which together form the bottom of the package. In a similar manner to the first and second back panels 102, 110, the first and second bottom back panels 122, 130 are attached to one another. To close the package 100, thereby forming the bottom, the first and second bottom back panels 122, 130 are attached to the bottom front panel 126, two portions of the left corner bottom panel 124 are attached to one another, and two portions of the right corner bottom panel 128 are attached to one another.

[0029] When package 100 is produced on a roll-fed packaging machine, many pieces of packaging material are provided one after the other on a reel of packaging material. By having many pieces of packaging material arranged in this manner, the lateral seal forming the bottom can be created at the same time that the lateral seal forming the top of the next package is created. After the lateral seals are created, the packages are separated from one another by cutting away the portions between the lateral seals.

[0030] To form a lateral seal, a first top sealing portion 134 and a second top sealing portion 132 and a first bottom sealing portion 136 and a second top sealing portion 138 can be provided. After the lateral seal is created, the packaging material can be separated such that the first top sealing portion 132 and the second top sealing portion 134 form an upper portion of a top surface of the package 100, and the first bottom sealing portion 136 and the second bottom sealing portion 138 form a lower portion of a bottom surface of the package 100. A longitudinal sealing portion 140 can be used to form a longitudinal seal.

[0031] If the package is produced in a blank-fed packaging machine, the longitudinal seal is pre-provided, i.e. the first rear panel 102 is attached to the second rear panel 110 via the longitudinal portion 140, so that a sleeve-shaped piece of packaging material is provided. In addition, the separation, also called cutting, is not performed in the blank-fed packaging machine, but rather when producing the blanks that are fed into the blank-fed packaging machine.

[0032] 2 generally illustrates the principle of a roll-fed packaging machine 200. A web 202 of packaging material is provided via a reel and fed in a feed direction A through the packaging machine 200. A tube 204 is formed from the web 202. Food product can be fed into the tube 204 from above using a pipe 206 in combination with a valve 208. In a folding and sealing device 210 a package 212 is formed from the tube 204.

[0033] FIG. 3 generally illustrates, by way of example, a packaging material 300 that can be used to form the package 100 .

[0034] Facing the surrounding space, an outer coating 302 may be provided. The outer coating 302 may serve the purpose of preventing water humidity from contacting a printed layer 304 placed inside the outer coating 302. The printed layer 304 may include ink or any other material used to provide printing on the package 100.

[0035] First and second paperboard layers 306, 308 may be provided on the inside of the printed layer 304. The first and second paperboard layers 306, 308 provide robustness to the package 100. The first paperboard layer 306 may be bleached paperboard with or without a clay coating. The second paperboard layer 308 may be bleached or unbleached paperboard.

[0036] A laminate 310 made from a plastic material can then be provided. The laminate 310 can be provided to prevent microorganisms from coming into contact with the product held inside the package 100.

[0037] An aluminum foil 312 may be provided on the inside of the laminate 310. The aluminum foil 312 may be provided to prevent light, oxygen and odors from contacting the product held inside the package 100, but also to allow aromas inside the package to emanate from the package 100. However, the aluminum foil 312 is not present in all types of packaging materials. For example, in packaging materials used for refrigerated products, i.e., products that are to be cooled, the aluminum foil 312 is most often omitted and replaced by a combination of a laminate and a paperboard layer.

[0038] Proximate the product held inside the package 100 may be provided first and second inner coatings 314, 316, made for example from a plastic material. One purpose of having these is to prevent the product from coming into direct contact with the aluminium foil 312.

[0039] FIG. 4 generally shows a cross-sectional view of the lower part 400 of the package 100 in more detail by way of example. The lower part 400 can be formed by a first part 402a and a second part 402b. Furthermore, the package 100 can include outer layers 404a, 404b, tough layers 406a, 406b, which can be paperboard layers, and plastic layers 408a, 408b. As shown in FIG. 3, these different layers can therefore include multiple layers. During the sealing step in the packaging machine 200, the plastic layers 408a, 408b can be heated so that they melt, for example by using an induction heating sealing technique or ultrasonic sealing. This, in combination with holding the first and second parts 402a, 402b against each other, allows the plastic layers 408a, 408b to form the fused layers 410a, 410b that are formed, thus forming the lower part 400.

[0040] During the sealing step, a sealing element with ridges can be used to hold the first and second parts 402a, 402b against each other. The ridges make it possible to provide additional pressure to the ridge press-fit area 412, which may be a sub-area of ​​the sealing part 414.

[0041] FIG. 5 illustrates an example cross-sectional view of the sealed portion 414 and ridge press-fit region 412 within the package 100 in greater detail.

[0042] Fig. 6 shows, by way of example, yet another cross-sectional view of the sealing portion. However, in the example shown in Fig. 6, all layers except for the plastic layers 408a, 408b have been removed to clearly show how the plastic layers 408a, 408b are affected by the sealing step, namely in that they become thinner due to the pressure applied during the sealing step.

[0043] 7 is yet another example of the sealed portion 414, but shown as a front view. The effect that the plastic layers 408a, 408b are affected during the sealing step is that light encounters different refractive indices when transmitted through the lower portion 400 or any other portion including the sealed portion 414. This then allows a quality assessment of the sealed portion 414 to be made by illuminating the lower portion 400 in a controlled manner.

[0044] 8a-c generally show, by way of example, an apparatus 800 for quality assessment of the sealed portion 414, which makes use of the fact that light transmitted through the sealed portion 414 is affected differently depending on how the packaging material 300 is affected during the sealing step.

[0045] As shown in Fig. 8a, a sample 802, which may be the lower part 400 shown in Fig. 4, may be placed in a sample holder 804 including multiple transparent plates 806. Light is provided by an illumination device 808 placed on a first side I of the sample holder 804 through a light control device 810 with a light emission area 812. After being transmitted through multiple transparent plates 806 and the sample 802, the light is captured by a camera 814, which may be coupled to a camera holder 816, which may be placed on a second side II of the sample holder 804.

[0046] Image data captured by camera 814 may be transmitted to computer 818, which may be a laptop computer as shown, but may also be a processing device built into camera 814 or any other processing device configured to manipulate the image data. Computer 818 may include a screen 820.

[0047] 8b shows the light control device 810 from above. The light emitting region 812 may have a first length L1 extending in a first length direction L1D and a first width W1 extending in a first width direction W1D. The first length direction L1D and the first width direction W1D may be perpendicular. The first length L1 may be greater than the first width W1.

[0048] 8c shows multiple transparent plates 806 from above. The sample 802 including the sealing portion 414 may have a second length L2 extending in a second length direction L2D and a second width W2 extending in a second width direction W2D. The second length direction L2D and the second width direction W2D may be perpendicular. The second length L2 may be greater than the second width W2. The sample 802 may be placed such that the first length direction L1D is parallel to the second length direction L2D.

[0049] Figures 9a and 9b show two examples of an apparatus 900 for quality assessment of the encapsulation portion 414. In Figure 9a, the apparatus 900 is shown without a polarizing filter, and in Figure 9b, the apparatus 900 is shown with a polarizing filter.

[0050] More specifically, as shown in Figure 9a, a sample holder 902 can be provided to hold a sample 904 having a ridge indented region 906. Light 908 is emitted from an illumination device 910 and passes through a light control device 912 before reaching the sample holder 902 and sample 904. The light passing through the sample holder 902 and sample 904 can be captured by a camera 914.

[0051] As shown in Fig. 9b, the apparatus 900 further includes a first polarizing filter 916 placed between the sample holder 902 and the sample 904 and a second polarizing filter 918 placed between the sample 904 and the camera 914. The first polarizing filter 916 may be a -45 degree polarizing filter and the second polarizing filter 918 may be a +45 degree polarizing filter. The effect of having the polarizing filters 916, 918 is that only light whose polarity is affected when transmitted through the enclosed portion 904 can be captured by the camera 914.

[0052] The light control device may also be used such that image data can be captured with the light control device in a diffuse light position and with the light control device in a high contrast position. Having image data captured with two different light settings has the advantage that different features can be determined more accurately. This can be combined with using different polarizations, for example high contrast and diffuse light. Linearly polarized light can have different angles to the sample, such as 0°, 30°, 45°, 90°, etc., which has the advantage that different features can be determined in the image. It is also possible to use circularly polarized light, which also has the advantage of allowing different features in the image to be detected.

[0053] The device 1000 may be embodied in many different ways. An example of an embodiment of the device 1000 is shown in Fig. 10. In this embodiment, there is no camera provided to capture the light transmitted through the seal, instead only a sample holder 1002, which here includes, among other things, an illumination device, and a magnification device 1004 are provided. To assess the quality of the seal, an operator, i.e. a user, can view the seal through the magnification device 1004. If a camera is provided, the magnification device 1004 can form part of a computer.

[0054] Figures 11a and 11b show another embodiment of the apparatus 1000. In line with the embodiment of the apparatus 1000 shown in Figure 10, a sample holder 1002 and a magnifying device 1004 can be provided. However, in addition to the embodiment shown in Figure 10, a camera holder 1100 can be provided. By using the camera holder 1100, a mobile phone with a camera 1102 or any other camera equipped device can be placed such that image data can be captured using the camera of the mobile phone 1102.

[0055] To assess the quality of the seal, different features may be taken into account. Figure 12 shows an example of a seal 1200. In this example, a seal border 1202 is determined using an image analysis algorithm. This may be done by taking advantage of the existence of a difference in pixel values ​​between pixels that do not belong to the seal, i.e. located above the seal border 1202 in Figure 12, and pixels that belong to the seal, i.e. located below the seal border 1202 in Figure 12. Furthermore, a reference line 1204 may be determined. In this example, the reference line 1204 is based on a ridge press line, i.e. a line formed by a ridge placed on one or both of the sealing jaws used in the sealing step. Instead of using the ridge press line as the reference line 1204, the cut line, i.e. the edge of the package, may be used as the reference line. When both the seal border 1202 and the reference line 1204 have been determined, a seal evaluation area 1206 may be determined. Although shown to cover only a portion of the width of the package, it should be understood that the seal 1206 may cover the entire width of the package. Additionally, instead of determining the seal portion 1206 based on the top seal boundary line depicted as seal boundary line 1202 and reference line 1204, the seal portion evaluation area 1206 may be based on the bottom seal boundary line and reference line 1204 located on the opposite side of reference line 1204. A further option is to determine the seal portion evaluation area 1206 on the top and bottom seal boundary lines. When using this option, reference line 1204 may be used as a guide to reliably identify the top and bottom seal boundary lines.

[0056] Alternatively or in combination with determining the occluded portion evaluation area 1206 , one or more distance measures may be determined between the reference line 1204 and the occluded portion boundary 1202 .

[0057] As pointed out above, different features may be considered when assessing the quality of the seal. The seal area 1206 may be one of these features. Different features may form a seal assessment feature set. As a general rule, multiple features that take into account different aspects will increase the reliability of the assessment, but the seal assessment feature set may include only one feature as well.

[0058] Another feature that may form part of the seal evaluation feature set is the boundary deviation measure. Figure 13 shows an example of a seal 1300 for which this measure is determined. As shown in Figure 12, a seal boundary 1302 and a reference line 1304 may be determined. To determine the boundary deviation measure, an ideal seal boundary 1306 may be used. The ideal seal boundary 1306 may be determined in different ways. One way to determine is to use the reference line 1304. Based on the reference line 1304 and a theoretical model, it can be determined, i.e. what the seal boundary 1302 should be in an ideal situation. As shown in Figure 13, the seal boundary 1302, which is the actual boundary of the seal, and the ideal seal boundary 1306, which is the theoretical boundary, i.e. a fixed point value, deviate from each other in several points. As a general rule, the more the two deviate, the more likely the seal is poorly sealed.

[0059] Another level of features that may form part of the sealed portion evaluation feature set is shown by way of example in Figure 14. In this example, the sealed portion includes an upper sealed portion boundary line 1402, a first reference line 1404, a second reference line 1406, and a lower sealed portion boundary line 1408. The first and second reference lines 1404, 1406 may be first and second ridge indentation lines.

[0060] 14, the bottom sealed portion boundary 1408 may include peripheral unsealed portions 1410. The depth of these peripheral unsealed portions 1410 may be determined and used as features of the sealed portion assessment feature set. As a general rule, the deeper the peripheral unsealed portions 1410, the more likely the seal is poor.

[0061] FIG. 15 shows yet another example of a sealed portion 1500. In keeping with the example shown in FIG. 14, the sealed portion 1500 includes an upper sealed portion boundary 1502, a first reference line 1504, a second reference line 1506, and a lower sealed portion boundary 1508. However, unlike the example shown in FIG. 14, the example shown in FIG. 15 includes an internal non-sealed portion 1510. Since the internal non-sealed portion 1510 may represent an insufficient seal, the area of ​​the internal non-sealed portion 1510 may be determined and form part of the sealed portion evaluation feature set. Although multiple internal non-sealed portions 1510 are shown as examples, a single internal non-sealed portion may be used as well. As a general rule, the larger the area of ​​the non-sealed portion 1510, the more likely the seal is insufficient.

[0062] Yet another feature that may form part of the seal part evaluation feature set is the baseline deviation measure. This feature may be determined by comparing the baseline to the ideal baseline 1512, where the first baseline 1504 is used in the example shown in FIG. 15. The ideal baseline 1512 may be determined in different ways. One option for determining the ideal baseline 1512 is by fitting a straight line to the multiple observations made when identifying the baseline 1504, for example by using regression analysis. One situation when the assumption that the baseline 1506 should be a straight line is correct is when the baseline 1504 describes a ridge press-in line and the ridge of the sealing jaw is a straight line. As a general rule, the more the two deviate, the more likely the seal is poor.

[0063] Furthermore, the sealed portion evaluation feature set may include the input sealing energy. By registering the amount of energy input during the sealing step, the reference feature set may be adapted so that, for example, if the sealed portion evaluation area 1206 depends on the energy used during sealing, this may be compensated for. The input sealing energy may also be used to determine whether an insufficient seal has been achieved in a straightforward manner. For example, if the input sealing energy is higher than a set threshold, this may indicate that the seal was not performed correctly, and therefore there is an increased risk that the sealed portion will not meet the set quality conditions.

[0064] Instead of using the ridge press line as the reference line, the cut line, i.e. the edge of the package, may be used as the reference line. Yet a further option is to use both the ridge press line and the cut line as reference lines.

[0065] Fig. 16 is a flow chart showing steps of a method for quality assessment of a seal 414. In a first step 1602, image data can be captured. In a second step 1604, reference lines 1204, 1304, 1404, 1504 can be identified in the image data. Then, seal boundary lines 1202, 1302, 1402, 1502 can be identified in a third step 1606. Based on the reference lines 1204, 1304, 1404, 1504 and the seal boundary lines 1202, 1302, 1402, 1502, a seal evaluation feature set can be determined in a fourth step 1608. In a fifth step 1610, the seal evaluation feature set can be compared with a reference feature set. If a match is found within a tolerance, the seal can be considered as meeting the set conditions, i.e. a sufficient seal has been achieved.

[0066] Optionally, in a sixth step 1612, an occlusion evaluation region 1206 is determined based on the reference line and the occlusion boundary, which may form part of the occlusion evaluation feature set.

[0067] Optionally, in a seventh step 1614, a boundary deviation measure is determined by comparing the enclosed part boundary 1302 with the ideal enclosed part boundary 1306, which may form part of the enclosed part evaluation feature set.

[0068] Optionally, in an eighth step 1616, a boundary deviation measure is determined by comparing the baseline 1504 to an ideal baseline 1512, which may form part of an occlusion sub-assessment feature set.

[0069] Optionally, in a ninth step 1618, peripheral unsealed portions 1410 may be identified, and in a tenth step 1620, the depth of the peripheral unsealed portions 1410 may be determined and form part of a seal portion evaluation feature set.

[0070] Optionally, in an eleventh step 1622, an internal unsealed portion 1510 may be identified, and in a twelfth step 1624, an area of ​​the internal unsealed portion 1510 may be determined and form part of a sealed portion evaluation feature set.

[0071] Although the steps are presented in a particular order, this should be viewed as one example of many possibilities.

[0072] From the above, although various embodiments of the present invention have been described and shown, the present invention is not limited thereto and may be embodied in other ways within the scope of the subject matter defined in the following claims.

Claims

1. 16. A method (1600) for quality assessment of a sealed portion (414) of a package (100), the package (100) comprising at least a tough layer (406a, 406b) and a plastic layer (408a, 408b), the sealed portion (414) being formed by holding a first portion (402a) and a second portion (402b) of the package (100) against one another while providing heat to melt the plastic layers (408a, 408b) of the first and second portions (402a, 402b) and thereby adhere the first and second portions (402a, 402b) to one another, the method (1600) comprising: Capturing (1602) image data depicting the enclosed portion (414) using a camera (814); Identifying (1604) a reference line (1204, 1304, 1404, 1504) within the image data; Identifying (1606) an occlusion boundary (1202, 1302, 1402, 1502) within the image data; determining (1608) an occlusion assessment feature based on said reference line (1204, 1304, 1404, 1504) and said occlusion boundary line (1202, 1302, 1402, 1502), said occlusion assessment feature including only one feature or multiple features taking into account different aspects; comparing 1610 the occlusion evaluation feature with a reference feature; The method (1600).

2. The method of claim 1 , wherein the occlusion evaluation features include at least one distance measure between the reference line (1204, 1404, 1504) and the occlusion boundary line (1202, 1302, 1402, 1502).

3. determining (1612) an occlusion evaluation area (1206) defined by the reference line (1204) and the occlusion boundary line (1202); The method of claim 1 or 2, wherein the occlusion evaluation feature comprises the occlusion evaluation area (1206).

4. determining (1614) a boundary line deviation measure by comparing the closure portion boundary line (1302) with an ideal closure portion boundary line (1306); The method of any one of claims 1 to 3, wherein the occlusion assessment feature comprises a first boundary line deviation measure.

5. determining (1616) a baseline deviation measure by comparing (1504) the baseline to an ideal baseline (1512); The method of any one of claims 1 to 4, wherein the occlusion assessment feature comprises the baseline deviation measure.

6. identifying (1618) a peripheral unenclosed portion (1410) having an open end facing the enclosed portion boundary line (1408); determining (1620) a depth of the peripheral non-sealed portion (1410) by determining a minimum distance between the peripheral non-sealed portion (1410) and the reference line (1404); Further comprising: The method of any one of claims 1 to 5, wherein the occlusion assessment feature comprises the depth of the peripheral unoccluded portion (1410).

7. identifying (1622) an interior non-enclosed portion (1510) within said enclosed portion (414); Determining (1624) an area of ​​the interior unenclosed portion (1510). Further comprising: The method of any one of claims 1 to 6, wherein the enclosure assessment feature comprises the area of ​​the interior unenclosed portion (1510).

8. The package (100) is a carton-based package for milk and other food products, and the robust layers (406a, 406b) are paperboard layers. The method according to any one of claims 1 to 7.

9. The method of any one of claims 1 to 8, wherein the reference lines (1204, 1304, 1404, 1504) describe a ridge press fit of the sealing portion (414).

10. The method of any one of claims 1 to 8, wherein the reference lines (1204, 1304, 1404, 1504) delineate cutting lines.

11. A computer program comprising instructions, when executed on a computer, causing said computer to carry out a method (1600) for quality assessment of a closure (414) of a package (100), comprising: the package (100) includes at least a tough layer (406a, 406b) and a plastic layer (408a, 408b), and the sealed portion (414) is formed by holding a first portion (402a) and a second portion (402b) of the package (100) against one another while providing heat to melt the plastic layers (408a, 408b) of the first and second portions (402a, 402b) and thereby adhere the first and second portions (402a, 402b) to one another; The method (1600) comprises: reading image data depicting the enclosed portion (414) from an image sensor connected to the computer or receiving the image data from a camera (814, 914) connected to the computer; Identifying (1604) a reference line (1204, 1304, 1404, 1504) within the image data; Identifying (1606) an occlusion boundary (1202, 1302, 1402, 1502) within the image data; determining (1608) an occlusion assessment feature based on said reference line (1204, 1304, 1404, 1504) and said occlusion boundary line (1202, 1302, 1402, 1502), said occlusion assessment feature including only one feature or multiple features taking into account different aspects; comparing 1610 the occlusion assessment feature with a reference feature; Including, Computer program.

Images