Heat sealing detection method and device

Abstract

The invention provides a heat-sealing detection method which comprises the following steps: S1, while carrying out hot-pressing edge sealing on a to-be-heat-sealed packaging bag, acquiring a thermal image of another heat-sealed packaging bag adjacent to the to-be-heat-sealed packaging bag; s2, performing comparative analysis on an image in at least part of the area in the obtained thermal image and an image in the same area in a set standard thermal image; and S3, if the parameters of the image in at least part of the area and the parameters of the image in the same area in the set standard thermal image are within a preset deviation range, the heat sealing detection result of the heat-sealed packaging bag is qualified, and otherwise, the heat sealing detection result is unqualified. The invention further provides a heat-sealing detection device used for executing the heat-sealing detection method, heat-sealing quality defects caused by reasons except heat-sealing pressure can be detected, the identification range of the heat-sealing quality defects is expanded, and the heat-sealing detection accuracy of the packaging bag is improved.

Description

Technical Field

[0001] The present invention relates to the field of flexible packaging, and in particular to a heat seal detection method and device. Background Art

[0002] The bag-making process in the flexible packaging industry is a continuous bag-making process. During the bag-making process, the inner heat-sealing layer of the plastic is in contact with each other through the molding process. The heating element heats the surface of the composite plastic, and the heat is transferred from the surface to the inner layer through the plastic film, so that the inner heat-sealing layer melts. Under the action of pressure, the melted inner heat-sealing layer is fused. After cooling, the heat-sealing layer of the overall structure is formed, achieving the fusion and sealing effect of the inner heat-sealing layer of the bag.

[0003] In this process, the fusion sealing effect of the heat-sealing layer needs to be checked after the packaging bag is taken out, and the inspection of the packaging bag is also a sampling inspection, that is, the packaging bag to be inspected is sent to a vacuum water bath back pressure instrument for a negative pressure test. If no bubbles appear in the water, it means that the sealing of the packaging bag is qualified. Since the packaging bag to be sampled for inspection has been tested in water, the packaging bag will be scrapped and cannot be delivered to customers. Therefore, it is impossible to inspect every packaging bag, and there will be a situation where the packaging bags with unqualified sealing are mixed with qualified products, and there is a risk of missed inspections.

[0004] In order to solve the above problems, CN112319942A discloses a packaging bag heat seal detection method and device, which determines whether the heat seal quality is qualified by collecting the position signal of the pressurizing component to identify the heat seal quality defects caused by the heat seal pressure change. However, since the detection is indirectly performed through the correlation between the heat seal position and the heat pressure quality, rather than directly through the parameters of the packaging bag itself, there will be inaccurate detection, and the detection method can only identify the heat seal quality defects caused by the heat seal pressure change, and cannot identify the heat seal quality defects caused by non-heat seal pressure changes, and the types of defects that can be identified are limited. Summary of the invention

[0005] In view of the deficiencies of the prior art, a heat seal detection method and device are provided.

[0006] To achieve the above object, the present invention provides a heat seal detection method, comprising the following steps: S1. Heat-pressing and edge-sealing the packaging bag to be heat-sealed; S2, obtaining a thermal image of the heat-sealed packaging bag; S3, comparing and analyzing the image in at least a partial area of ​​the acquired thermal image with the image in the same area of ​​a set standard thermal image; and S4. If the parameters of the image in at least a part of the area are within a predetermined deviation from the parameters of the image in the same area in the set standard thermal image, the heat sealing test result of the heat-sealed packaging bag is qualified, otherwise the heat sealing test result is unqualified.

[0007] According to one embodiment of the present invention, step S3 includes: S31, extracting a first temperature parameter of each pixel in the image in at least a partial area, and a first shape distribution of all pixels in the image in at least a partial area; S32, comparing the first temperature parameter and the first shape distribution with the standard temperature parameter of each pixel point and the standard shape distribution of all pixel points in the same area of ​​the standard thermal image; In step S4, if the difference between the first temperature parameter and the standard temperature parameter is within a predetermined temperature deviation, and the first shape distribution and the standard shape reach a predetermined shape similarity, the heat sealing test result is qualified, otherwise the heat sealing test result is unqualified.

[0008] According to one embodiment of the present invention, step S2 includes obtaining a thermal image of the upper end seal and a thermal image of the lower end seal of the heat-sealed packaging bag; After step S4, the method further includes: S5. When the heat seal test result is unqualified, an alarm is issued and the unqualified heat-sealed packaging bags are rejected.

[0009] According to one embodiment of the present invention, the present invention further provides a heat seal detection method, characterized in that it comprises the following steps: S1. While performing heat-pressing edge sealing on the packaging bag to be heat-sealed, obtain a thermal image of another heat-sealed packaging bag adjacent to the packaging bag to be heat-sealed; S2, comparing and analyzing the image in at least a partial area of ​​the acquired thermal image with the image in the same area of ​​a set standard thermal image; and S3. If the parameters of the image in at least a part of the area are within a predetermined deviation from the parameters of the image in the same area in the set standard thermal image, the heat sealing test result of the heat-sealed packaging bag is qualified, otherwise the heat sealing test result is unqualified.

[0010] According to one embodiment of the present invention, step S2 includes: S21, extracting a first temperature parameter of each pixel in the image in at least a partial area, and a first shape distribution of all pixels in the image in at least a partial area; S22, comparing the first temperature parameter and the first shape distribution with the standard temperature parameter of each pixel point and the standard shape distribution of all pixel points in the same area of ​​the standard thermal image; In step S3, if the difference between the first temperature parameter and the standard temperature parameter is within the predetermined temperature deviation, and the similarity between the first shape distribution and the standard shape distribution reaches the predetermined shape similarity, the heat sealing test result is qualified, otherwise the heat sealing test result is unqualified.

[0011] According to one embodiment of the present invention, obtaining a thermal image of another heat-sealed packaging bag adjacent to the packaging bag to be heat-sealed in step S1 specifically includes: Acquire a thermal image of the upper end seal of another heat-sealed packaging bag adjacent to the packaging bag to be heat-sealed; and Acquire a thermal image of the seal of the lower end surface of another heat-sealed packaging bag adjacent to the packaging bag to be heat-sealed; After step S3, the method further includes: S4. When the heat seal test result is unqualified, an alarm is issued and the unqualified heat-sealed packaging bags are rejected.

[0012] The present invention also provides a heat seal detection device, comprising: A conveying mechanism, used for conveying packaging bags to be heat-sealed; The heat sealing mechanism is arranged in the conveying direction of the conveying mechanism and is used for heat-pressing and sealing the packaging bag to be heat-sealed; A sensor is provided at the output end of the heat sealing mechanism. When the heat sealing mechanism performs heat-pressing edge sealing on the packaging bag to be heat-sealed, the sensor can identify the displacement signal of the heat sealing mechanism and then convert the displacement signal into an image acquisition signal; a controller, electrically connected to the conveying mechanism, the heat sealing mechanism and the sensor, respectively, for controlling the conveying mechanism to convey the packaging bag to be heat-sealed, and for controlling the heat sealing mechanism to perform heat-pressing edge sealing on the packaging bag to be heat-sealed; the controller also receives an image acquisition signal from the sensor, and issues a detection control signal according to the image acquisition signal; a detection mechanism, disposed on the conveying line of the conveying mechanism, electrically connected to the controller, for receiving the detection control signal, and acquiring a thermal image of another heat-sealed packaging bag adjacent to the packaging bag heat-sealed by the heat-sealing mechanism according to the detection control signal, and then sending the thermal image to the controller; Among them, after receiving the thermal image, the controller compares and analyzes the image in at least a partial area of ​​the thermal image with the image in the same area of ​​a set standard thermal image; if the parameters of the image in at least a partial area are within a predetermined deviation from the parameters of the image in the same area of ​​the set standard thermal image, the heat sealing test result of the heat-sealed packaging bag is qualified, otherwise the heat sealing test result is unqualified.

[0013] According to one embodiment of the present invention, the controller comprises: A control module is electrically connected to the conveying mechanism, the heat sealing mechanism, and the sensor, respectively, and is used to control the conveying mechanism to convey the packaging bag to be heat-sealed, and to control the heat sealing mechanism to perform heat-pressing edge sealing on the packaging bag to be heat-sealed; and is also used to receive an image acquisition signal from the sensor, and to issue a detection control signal according to the image acquisition signal; an analysis module, configured to receive the thermal image sent by the detection mechanism, and then extract a first temperature parameter of each pixel in at least a portion of the thermal image, and a first shape distribution of all pixels in at least a portion of the thermal image; and The judgment module is used to compare the first temperature parameter with the standard temperature parameter of each pixel point in the same area of ​​the image in the set standard thermal image, to judge whether the difference between the first temperature parameter and the standard temperature parameter is within a predetermined temperature deviation, and to compare the first shape distribution with the standard shape distribution of all pixel points in the same area of ​​the set standard thermal image, to judge whether the similarity between the first shape distribution and the standard shape distribution reaches a predetermined shape similarity. If both are true, the heat sealing test result is judged to be qualified.

[0014] According to an embodiment of the present invention, the controller further comprises a storage module connected to the analysis module, and the storage module is used to store the standard thermal image, the predetermined temperature deviation and the predetermined shape similarity.

[0015] According to one embodiment of the present invention, the detection mechanism includes: A first infrared imaging camera is disposed above the conveying line of the conveying mechanism, facing the upper end surface of the packaging bag, and is used to obtain a thermal image of the seal of the upper end surface of the packaging bag; and The second infrared imaging camera is arranged below the conveying line of the conveying mechanism, facing the lower end surface of the packaging bag, and is used to obtain a thermal image of the seal of the lower end surface of the packaging bag.

[0016] In summary, the present invention performs heat-pressing edge sealing on the packaging bag to be heat-sealed; obtains a thermal image of the packaging bag after heat sealing; compares and analyzes the image in at least a partial area of ​​the obtained thermal image with the image in the same area of ​​a set standard thermal image; and determines whether the parameters of the image in at least a partial area and the parameters of the image in the same area of ​​the set standard thermal image are within a predetermined deviation, so as to determine whether the heat sealing test result of the packaging bag after heat sealing is qualified, thereby realizing non-destructive testing of the packaging bag, detecting heat sealing quality defects caused by reasons other than heat sealing pressure, realizing multi-type detection of heat sealing quality defects of the packaging bag, expanding the recognition range of heat sealing quality defects, and improving the accuracy of the heat sealing effect detection results of the packaging bag. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings: Figure 1 Flow chart of the heat seal detection method in the embodiment; Figure 2 Schematic diagram of the hot pressing edge sealing and detection sequence of the packaging bag in the embodiment; Figure 3 Schematic diagram of a standard thermal image showing a qualified heat seal test result in the embodiment; Figure 4 is a schematic diagram of a thermal image in which the difference between the first temperature parameter and the standard temperature parameter exceeds a predetermined temperature deviation in the embodiment; Figure 5 is a schematic diagram of a thermal image in which the similarity between the first shape distribution and the standard shape distribution reaches a predetermined shape similarity in the embodiment; Figure 6 is a schematic diagram of a thermal image in which the similarity between the first shape distribution and the standard shape distribution does not reach a predetermined shape similarity in the embodiment; Figure 7 is a flow chart of a heat seal detection method in another embodiment; Figure 8 It is a structural diagram of the heat seal detection device in the embodiment; Fig. 9 3D is a three-dimensional diagram of the detection mechanism of the heat seal detection device in the embodiment.

[0018] Description of Reference Numerals A-automatically selected area; B-second level temperature abnormal area; C-first level temperature abnormal area; 01-Packing bag; 1-frame; 11-first infrared imaging camera; 12-second infrared imaging camera. DETAILED DESCRIPTION

[0019] The following will disclose multiple embodiments of the present invention with drawings. For the purpose of clear description, many practical details will be described together in the following description. However, it should be understood that these practical details should not be used to limit the present invention. That is, in some embodiments of the present invention, these practical details are not necessary. In addition, for the purpose of simplifying the drawings, some conventional structures and components will be depicted in a simple schematic manner in the drawings.

[0020] In addition, in the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes, and do not specifically refer to the order or sequence, nor are they used to limit the present invention. They are only used to distinguish components or operations described with the same technical terms, and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0021] Embodiment 1 This embodiment provides a heat seal detection method, see Figure 1 , Figure 1 : is a flow chart of the heat seal detection method in this embodiment, and the heat seal detection method includes the following steps.

[0022] Step S1: while performing heat-compression edge sealing on a packaging bag to be heat-sealed, a thermal image of another heat-sealed packaging bag adjacent to the packaging bag to be heat-sealed is obtained.

[0023] Specifically, after each packaging bag is heat-sealed, a heat-sealed area will be formed at the corresponding part of the packaging bag surface. Figure 2 As shown, Figure 2 The schematic diagram is a diagram of N packaging bags arranged in sequence (the packaging bags are continuous composite films before heat sealing and cutting. When making the bags, the three sides of the packaging bags are heat-pressed and sealed at the corresponding positions of the composite films according to the predetermined packaging bag specifications, and then cut and separated to make independent finished packaging bags. This embodiment shows the process of heat-pressing and sealing the bottom edge of the packaging bags). The N packaging bags are transported along the direction F. During the transportation process, the first, second, third, fourth...M-1, M, M+1...N-2, N-1, and finally the Nth packaging bag are heat-sealed in sequence. The first heat-sealed packaging bag has a heat-sealed area A at its bottom. 1 The second heat-sealed packaging bag has a heat-sealed area A at its bottom. 2 The third heat-sealed packaging bag has a heat-sealed area A at its bottom. 3 The fourth heat-sealed packaging bag has a heat-sealed area A at its bottom. 4 ...The M-1th heat-sealed packaging bag has a heat-sealed area A at its bottom （m-1） The Mth heat-sealed packaging bag has a heat-sealed area A at its bottom （m） The M+1th heat-sealed packaging bag has a heat-sealed area A at its bottom. （m+1） .

[0024] When the M+1th packaging bag is heat-sealed, the thermal image of the Mth packaging bag is acquired simultaneously. The acquired thermal image of the Mth packaging bag (see Figure 2 The area outlined by the dashed line in the middle includes the heat-sealed area A of the Mth packaging bag. （m） 、Heat-sealed area A of part of the M+1 packaging bag （m+1） , Heat-sealed area A of part of the M-1 packaging bag （m-1） And other unsealed areas.

[0025] Step S2: Compare and analyze the image in at least a partial area of ​​the acquired thermal image with the image in the same area of ​​a set standard thermal image.

[0026] In step S2, since the acquired thermal image also includes a portion of the heat-sealed area of ​​the adjacent packaging bag, if the portion of the heat-sealed area of ​​the adjacent packaging bag is also used as the object of comparative analysis of the thermal image of the packaging bag, it will affect the detection result of the packaging bag. Therefore, it is necessary to select a portion of the heat-sealed area in the acquired thermal image for comparative analysis. Figure 2 When the thermal image of the Mth packaging bag is obtained, the image in the partial area for comparative analysis is the heat-sealed area A including the Mth packaging bag. （m） When selecting a partial area including the heat-sealed area, the image is divided into a first area and a second area by threshold segmentation. The area composed of pixels with temperature values ​​higher than the threshold is the first area, and the area composed of pixels with temperature values ​​lower than the threshold is the second area. The highest point of the contour in the first area, that is, the pixel with the largest longitudinal coordinate value, is then combined to automatically select the area. Figure 3 , Figure 3 Schematic diagram of the thermal image of the packaging bag obtained in this embodiment. Figure 3 Area A within the black line is the automatically selected area. In addition, you can also manually select a portion of the acquired thermal image that includes the heat-sealed area for comparative analysis.

[0027] The steps for determining the standard thermal image in step S2 are as follows: select a heat-sealed packaging bag as a sample bag, and obtain the thermal image of the sample bag through step S1; according to traditional detection methods, the heat sealing effect of the sample bag is detected by naked eye observation, water immersion detection, etc.; if the heat sealing test result of the sample bag is qualified, the thermal image of the sample bag is set as the standard thermal image. The standard thermal image is determined separately before step S1, and the standard thermal image can be updated and replaced according to the operation of the packaging bag production line. After selecting the partial area image including the heat-sealed area of ​​the acquired thermal image, the area image corresponding to the selected part is also matched in the standard thermal image for comparative analysis.

[0028] Step S3: If the parameters of the image in at least part of the area are within the predetermined deviation from the parameters of the image in the same area in the set standard thermal image, the heat seal test result of the heat-sealed packaging bag is qualified, otherwise the heat seal test result is unqualified. The predetermined deviation is a range, which can be set in advance according to the actual production situation of the packaging bag. First, the parameters of the comparison area in the acquired thermal image are subtracted from the parameters of the same area in the standard thermal image to obtain the difference between the parameters of the comparison area of ​​the acquired thermal image and the standard thermal image, and the difference is compared with the predetermined deviation. If the difference is within the predetermined deviation range, the test result is qualified, otherwise the heat seal test result is unqualified.

[0029] In the embodiment of the present application, by the method in the embodiment of the present application, while the heat-sealed packaging bag is heat-sealed, a thermal image of another heat-sealed packaging bag adjacent to the packaging bag to be heat-sealed is obtained. This is to facilitate the control of the heat-sealing effect of the packaging bag according to the relevant parameters of the heat-sealed area in the thermal image of the heat-sealed packaging bag. At the same time, the image of at least a part of the area in the acquired thermal image is compared and analyzed with the image in the same area in the set standard thermal image, and it is determined whether the parameters of the image in at least a part of the area are within the predetermined deviation from the parameters of the image in the same area in the set standard thermal image, so as to facilitate the judgment of the heat-sealing result of the heat-sealed packaging bag, realize the automatic multi-type detection of the heat-sealing quality of the packaging bag, and improve the accuracy of the heat-sealing effect detection results of the packaging bag.

[0030] Continue to see Figure 1 In step S2, the image in at least a part of the area of ​​the acquired thermal image is compared and analyzed with the image in the same area of ​​the set standard thermal image. In the specific implementation process of this application, the following steps are specifically performed: Step S21: extracting a first temperature parameter of each pixel in the image within at least a partial area, and a first shape distribution of all pixels in the image within at least a partial area.

[0031] In step S21, the first temperature parameter is the temperature value of each pixel in the selected partial area image, and the parameter T 1 The first shape distribution is used to describe the shape characteristics of the selected partial area image, using the feature vector V 1 Represents. The feature vector V 1 =(A 1 , P 1 ), where A 1 is the area eigenvalue, P 1 is the perimeter eigenvalue, where the area eigenvalue A 1 and the perimeter eigenvalue P 1 The steps to obtain are as follows: (1) Determine the high temperature threshold, perform binarization on the selected area image, set the pixels with a temperature higher than the threshold to 1, and set the pixels with a temperature lower than the threshold to 0, to obtain a binary image, and count the pixels of the binary image to obtain the area feature value A. 1 ; (2) Extract the edge of the selected area image, determine the edge pixels, set the edge pixels to 1, and set the non-edge pixels to 0 to obtain a binary image. Extract the contour of the binary image shape and perform smoothing to remove noise and small irregular parts. Calculate the contour perimeter and obtain the perimeter eigenvalue P. 1 .

[0032] Step S22: comparing the first temperature parameter and the first shape distribution with the standard temperature parameter of each pixel point and the standard shape distribution of all pixels points in the same area of ​​the standard thermal image.

[0033] In step S22, the standard temperature parameter is the temperature value of each pixel in the image in the same area of ​​the standard thermal image, and the parameter T 0 Indicates that the standard shape distribution is used to describe the shape characteristics of the selected partial area image, with the feature vector V 0 Represents. The feature vector V 0 =(A 0 , P 0 ), where A 0 is the standard area characteristic value, P 0 is the standard perimeter eigenvalue, where the standard area eigenvalue A 0 and the standard perimeter eigenvalue P 0 The steps to obtain are as follows: (1) Determine the high temperature threshold, perform binarization on the image of the same area in the standard thermal image, set the pixels with a temperature higher than the threshold to 1, and set the pixels with a temperature lower than the threshold to 0, to obtain a binary image, and count the pixels of the binary image to obtain the standard area feature value A. 0 ; (2) Extract the edge of the image in the same area of ​​the standard thermal image, determine the edge pixels, set the edge pixels to 1, and set the non-edge pixels to 0 to obtain a binary image. Extract the contour of the binary image shape and perform smoothing to remove noise and small irregular parts. Calculate the contour perimeter and obtain the standard perimeter eigenvalue P. 0 .

[0034] When comparing, calculate the first temperature parameter T 1 With standard temperature parameter T 0 The temperature difference d T =T 0 -T 1, and calculate the first shape distribution V 1 and the standard shape distribution V 0 for the shape similarity . Use the temperature difference T to represent the difference between the first temperature parameter T 1 and the standard temperature parameter T0, and use the value of the shape similarity d(V 1 , V 0 ) to represent the difference between the first shape distribution V 1 and the standard shape distribution V 0 .

[0035] Correspondingly, in step S3, if the difference between the first temperature parameter and the standard temperature parameter is within the predetermined temperature deviation, and the similarity between the first shape distribution and the standard shape distribution reaches the predetermined shape similarity, the heat seal detection result is qualified; otherwise, the heat seal detection result is unqualified.

[0036] Specifically, the predetermined temperature deviation is (-x, +x), and the predetermined shape similarity is y. When the temperature difference -x < d T < +x, and the shape similarity d(V 1 , V 0 ) < y, the heat seal detection result is qualified; otherwise, the heat seal detection result is unqualified.

[0037] See Figure 3 and Figure 4 , Figure 3 is a schematic diagram of a thermal image in the embodiment where the difference between the first temperature parameter and the standard temperature parameter exceeds the predetermined temperature deviation, Figure 4 is a schematic diagram of a standard thermal image with a qualified heat seal detection result in the embodiment. When the difference exceeds the negative predetermined temperature deviation value (i.e., d T ≤ -x), it indicates that the heat of the heat seal is insufficient, that is, the pressure of the heat seal is insufficient or the packaging bag material is too thin, resulting in unqualified heat seal quality of the packaging bag. It should be noted that the value of x can be set in advance according to the actual production situation of the packaging bag. In this embodiment, the predetermined temperature deviation is (-5, +5), that is, when the temperature difference is within the range of ±5°C, the heat seal temperature is normal. The blue-circled area C and the red-circled area B show different degrees of temperature abnormality. The blue-circled area C indicates that the temperature difference in this area is outside the positive and negative predetermined temperature deviation ranges (i.e., d T ≤ -x or +x ≤ d T ), which is the first-level temperature abnormality area. The red-circled area B indicates that the degree of temperature abnormality in this area is higher than that of the blue-circled area C, which is the second-level temperature abnormality area.

[0038] See Figure 5 and Figure 6 , Figure 5It is a schematic diagram showing that the similarity between the first shape distribution of the thermal image of the packaging bag and the standard shape distribution reaches a predetermined shape similarity in this embodiment. Figure 6 This is a schematic diagram showing that the similarity between the first shape distribution of the thermal image of the packaging bag and the standard shape distribution in this embodiment does not reach the predetermined shape similarity. Figure 6 The shape distribution similarity of the selected part of the thermal image of the heat-sealed packaging bag in the above example does not reach the predetermined shape similarity, that is, y ≤ d(V 1 , V 0 ), indicating that the heat seal position is offset or the seal is incomplete.

[0039] In this embodiment, the step S1 of acquiring a thermal image of another heat-sealed packaging bag adjacent to the packaging bag to be heat-sealed specifically includes the following steps.

[0040] Step S11: Acquire a thermal image of the upper end seal of another heat-sealed packaging bag adjacent to the packaging bag to be heat-sealed.

[0041] Step S12: Acquire a thermal image of the seal of the lower end surface of another heat-sealed packaging bag adjacent to the packaging bag to be heat-sealed.

[0042] This enables a more comprehensive detection of the seal of the packaging bag. It should be noted that thermal images of the packaging bag at other angles can also be collected according to actual conditions in order to more comprehensively detect the heat sealing condition of the packaging bag.

[0043] In this embodiment, after step S3, the following steps are further included: Step S4: When the heat seal test result is unqualified, an alarm is issued and the unqualified heat-sealed packaging bags are removed, thereby achieving post-processing of unqualified packaging bags and improving the entire bag-making process of the production line.

[0044] The heat seal detection method in this embodiment not only realizes non-destructive detection of packaging bags, but also realizes multi-type detection of heat seal quality defects of packaging bags, and can detect heat seal quality defects caused by reasons other than heat seal pressure, thereby expanding the recognition range of heat seal quality defects and improving the accuracy of heat seal effect detection results of packaging bags.

[0045] Embodiment 2 This embodiment provides a heat seal detection method, see Figure 7 , Figure 7 : is a flow chart of the heat seal detection method in this embodiment, and the heat seal detection method includes the following steps.

[0046] Step S1: performing heat-pressing edge sealing on the packaging bag to be heat-sealed.

[0047] Step S2: Acquire a thermal image of the heat-sealed packaging bag.

[0048] Specifically, after each packaging bag is heat-sealed, a heat-sealed area will be formed at the corresponding position on the surface of the packaging bag. Figure 2 As shown, N packaging bags are transported along direction F. During the transport process, the 1st, 2nd, 3rd, 4th, ... M-1st, Mth, M+1th, ... N-2th, N-1th, until the Nth packaging bag is heat-sealed in sequence. The 1st heat-sealed packaging bag has a heat-sealed area A1 at its bottom, the 2nd heat-sealed packaging bag has a heat-sealed area A2 at its bottom, the 3rd heat-sealed packaging bag has a heat-sealed area A3 at its bottom, the 4th heat-sealed packaging bag has a heat-sealed area A4 at its bottom, and the M-1st heat-sealed packaging bag has a heat-sealed area A5 at its bottom. （m-1） The Mth heat-sealed packaging bag has a heat-sealed area A at its bottom （m） The M+1th heat-sealed packaging bag has a heat-sealed area A at its bottom. （m+1） .

[0049] When the Mth package bag is heat-sealed, a thermal image of the Mth package bag is obtained. The thermal image of the Mth package bag (see Figure 2 The area outlined by the dashed line in the middle includes the heat-sealed area A of the Mth packaging bag. （m） , Heat-sealed area A of part of the M+1 packaging bag （m+1） , Heat-sealed area A of part of the M-1 packaging bag （m-1） And other unsealed areas.

[0050] Step S3: Compare and analyze the image in at least a partial area of ​​the acquired thermal image with the image in the same area of ​​a set standard thermal image.

[0051] Since the acquired thermal image also includes the heat-sealed area of ​​the adjacent packaging bag, if the heat-sealed area of ​​the adjacent packaging bag is also used as the object of the thermal image comparison analysis of the packaging bag, it will affect the detection result of the packaging bag. Therefore, it is necessary to select a part of the area including the heat-sealed area in the acquired thermal image for comparison analysis. Figure 2 When the thermal image of the Mth packaging bag is obtained, the image in the partial area for comparative analysis is the heat-sealed area A including the Mth packaging bag. （m） When selecting a partial area including the heat-sealed area, the image is divided into a first area and a second area by threshold segmentation. The area composed of pixels with temperature values ​​higher than the threshold is the first area, and the area composed of pixels with temperature values ​​lower than the threshold is the second area. The highest point of the contour in the first area, that is, the pixel with the largest longitudinal coordinate value, is then combined to automatically select the area. Figure 3 , Figure 3 Schematic diagram of the thermal image of the packaging bag obtained in this embodiment. Figure 3Area A within the black line is the automatically selected area. In addition, you can also manually select a portion of the acquired thermal image that includes the heat-sealed area for comparative analysis.

[0052] The steps for determining the standard thermal image in step S3 are as follows: a heat-sealed packaging bag is selected as a sample bag, and a thermal image of the sample bag is obtained through step S1; the heat-sealing effect of the sample bag is tested by visual observation, water immersion test, etc. according to traditional testing methods; if the heat-sealing test result of the sample bag is qualified, the thermal image of the sample bag is set as the standard thermal image. After selecting the partial area image including the heat-sealed area of ​​the acquired thermal image, the area image corresponding to the selected part is also matched in the standard thermal image for comparative analysis.

[0053] Step S4: If the parameters of the image in at least a part of the area are within a predetermined deviation from the parameters of the image in the same area in the set standard thermal image, the heat seal test result of the heat-sealed packaging bag is qualified, otherwise the heat seal test result is unqualified.

[0054] In step S4, the predetermined deviation is a range, which is set in advance according to the actual production situation of the packaging bag. First, the parameters of the comparison area in the acquired thermal image are subtracted from the parameters of the same area in the standard thermal image to obtain the difference between the parameters of the comparison area of ​​the acquired thermal image and the standard thermal image. The difference is compared with the predetermined deviation. If the difference is within the predetermined deviation range, the test result is qualified, otherwise the heat seal test result is unqualified.

[0055] In the embodiment of the present application, through the method in the embodiment of the present application, after the heat-sealed packaging bag is heat-pressed and edge-sealed, the thermal image of the heat-sealed packaging bag is obtained, so as to control the heat-sealing effect of the packaging bag according to the relevant parameters of the heat-sealed area in the thermal image of the heat-sealed packaging bag. At the same time, the image in at least a part of the area of ​​the acquired thermal image is compared and analyzed with the image in the same area of ​​the set standard thermal image, and it is determined whether the parameters of the image in at least a part of the area are within the predetermined deviation from the parameters of the image in the same area of ​​the set standard thermal image, so as to determine the heat-sealing result of the heat-sealed packaging bag, realize the automatic multi-type detection of the heat-sealing quality of the packaging bag, and improve the accuracy of the heat-sealing effect detection result of the packaging bag.

[0056] Continue to see Figure 2 In step S3, the image in at least a part of the area of ​​the acquired thermal image is compared and analyzed with the image in the same area of ​​the set standard thermal image. In the specific implementation process of this application, the following steps are specifically performed: Step S31: extracting a first temperature parameter of each pixel in the image within at least a partial area, and a first shape distribution of all pixels in the image within at least a partial area.

[0057] In step S31, the first temperature parameter is the temperature value of each pixel in the selected partial area image, and the parameter T 1 The first shape distribution is used to describe the shape characteristics of the selected partial area image, using the feature vector V 1 Represents. The feature vector V 1 =(A 1 , P 1 ), where A 1 is the area eigenvalue, P 1 is the perimeter eigenvalue, where the area eigenvalue A 1 and the perimeter eigenvalue P 1 The steps to obtain are as follows: (1) Determine the high temperature threshold, perform binarization on the selected area image, set the pixels with a temperature higher than the threshold to 1, and set the pixels with a temperature lower than the threshold to 0, to obtain a binary image, and count the pixels of the binary image to obtain the area feature value A. 1 ; (2) Extract the edge of the selected area image, determine the edge pixels, set the edge pixels to 1, and set the non-edge pixels to 0 to obtain a binary image. Extract the contour of the binary image shape and perform smoothing to remove noise and small irregular parts. Calculate the contour perimeter and obtain the perimeter eigenvalue P. 1 .

[0058] Step S32: Compare the first temperature parameter and the first shape distribution with the standard temperature parameter of each pixel point and the standard shape distribution of all pixels points in the same area of ​​the standard thermal image. Specifically, the standard thermal image is a packaging bag that has been verified to be heat-sealed and qualified during normal production.

[0059] In step S32, the standard temperature parameter is the temperature value of each pixel in the image in the same area of ​​the standard thermal image, and the parameter T 0 Indicates that the standard shape distribution is used to describe the shape characteristics of the selected partial area image, with the feature vector V 0 Represents. The feature vector V 0 =(A 0 , P 0 ), where A 0 is the standard area characteristic value, P 0 is the standard perimeter eigenvalue, where the standard area eigenvalue A 0 and the standard perimeter eigenvalue P 0 The steps to obtain are as follows: (1) Determine the high-temperature threshold, perform binarization processing on the images of the same region in the standard thermal image, set the pixel points with temperatures higher than the threshold to 1, and set the pixel points with temperatures lower than the threshold to 0 to obtain a binary image, and count the pixel points of the binary image to obtain the standard area feature value A. 0 ; (2) Extract the edges of the images of the same region in the standard thermal image, determine the edge pixel points, set the edge pixel points to 1, and set the non-edge pixel points to 0 to obtain a binary image, extract the contours of the shape of the binary image, and perform smoothing processing to remove noise and small irregular parts, calculate the contour perimeter, and obtain the standard perimeter feature value P. 0 .

[0060] Specifically, when comparing, calculate the temperature difference d 1 between the first temperature parameter T 0 and the standard temperature parameter T T = T 0 - T 1 , and calculate the shape similarity 1 between the first shape distribution V 0 and the standard shape distribution V . Use the temperature difference d T to represent the difference between the first temperature parameter T 1 and the standard temperature parameter T 0 , and use the value of the shape similarity d(V 1 , V 0 ) to represent the difference between the first shape distribution V 1 and the standard shape distribution V 0 .

[0061] Correspondingly, in step S4, the specific steps are as follows: If the difference between the first temperature parameter and the standard temperature parameter is within the predetermined temperature deviation, and the similarity between the first shape distribution and the standard shape distribution reaches the predetermined shape similarity, the heat seal detection result is qualified; otherwise, the heat seal detection result is unqualified.

[0062] Specifically, the predetermined temperature deviation is (-x, +x), and the predetermined shape similarity is y. When the temperature difference -x < d T < +x, and the shape similarity d(V 1 , V 0 ) < y, the heat seal detection result is qualified; otherwise, the heat seal detection result is unqualified.

[0063] See Figure 3 and Figure 4 , Figure 3 is a schematic diagram of a thermal image in which the difference between the first temperature parameter and the standard temperature parameter in the embodiment exceeds the predetermined temperature deviation. Figure 4Schematic diagram of a standard thermal image of a qualified heat seal test result in the embodiment. T ≤ -x), it means that the heat of heat sealing is insufficient, that is, the heat sealing pressure is insufficient or the packaging bag material is too thin, resulting in unqualified heat sealing quality of the packaging bag. It should be noted that the value of x can be set in advance according to the actual production situation of the packaging bag. In this embodiment, the predetermined temperature deviation is (-5, +5), that is, when the temperature difference is within the range of ±5°C, the heat sealing temperature is normal. The blue circled area C and the red circled area B show different degrees of temperature anomaly. The blue circled area C indicates that the temperature difference in this area is outside the positive and negative predetermined temperature deviation range (that is, d T ≤ -x or +x ≤ d T ), which is the first-level temperature anomaly area. The red circled area B indicates that the degree of temperature anomaly in this area is higher than that in the blue circled area C, which is the second-level temperature anomaly area.

[0064] See also Figure 5 and Figure 6 , Figure 5 It is a schematic diagram showing that the similarity between the first shape distribution of the thermal image of the packaging bag and the standard shape distribution reaches a predetermined shape similarity in this embodiment. Figure 6 This is a schematic diagram showing that the similarity between the first shape distribution of the thermal image of the packaging bag and the standard shape distribution in this embodiment does not reach the predetermined shape similarity. Figure 6 The shape distribution similarity of the selected part of the thermal image of the heat-sealed packaging bag in the above example does not reach the predetermined shape similarity, that is, y ≤ d(V 1 , V 0 ), indicating that the heat seal position is offset or the seal is incomplete.

[0065] In this embodiment, step S2 includes acquiring a thermal image of the upper end seal and a thermal image of the lower end seal of the heat-sealed packaging bag, thereby achieving a more comprehensive detection of the packaging bag seal. It should be noted that thermal images of other angles of the packaging bag can also be acquired according to actual conditions, so as to more comprehensively detect the heat sealing condition of the packaging bag.

[0066] After step S4, step S5 is also included: when the heat seal test result is unqualified, an alarm is issued and unqualified heat-sealed packaging bags are removed, thereby achieving post-processing of unqualified packaging bags and improving the entire bag-making process of the production line.

[0067] The heat seal detection method in this embodiment not only realizes non-destructive detection of packaging bags, but also realizes multi-type detection of heat seal quality defects of packaging bags, and can detect heat seal quality defects caused by reasons other than heat seal pressure, thereby expanding the recognition range of heat seal quality defects and improving the accuracy of heat seal effect detection results of packaging bags.

[0068] Embodiment 3 This embodiment provides a heat seal detection device for implementing the above heat seal detection method. Figure 8 and Fig. 9 , Figure 8 is a structural diagram of a heat seal detection device in an embodiment, Fig. 9 3D is a three-dimensional diagram of the detection mechanism of the heat seal detection device in the embodiment. The heat seal detection device includes a conveying mechanism, a heat seal mechanism, a sensor, a controller and a detection mechanism.

[0069] The conveying mechanism is arranged through the heat sealing mechanism and the detection mechanism, and is used to convey the packaging bag to be heat-sealed to the bottom of the heat sealing mechanism, and at the same time convey the heat-sealed packaging bag adjacent to the packaging bag to be heat-sealed to the detection position of the detection mechanism.

[0070] The heat sealing mechanism is arranged in the conveying direction of the conveying mechanism, and is used for performing heat-pressing edge sealing on the packaging bag to be heat-sealed.

[0071] The sensor is arranged at the output end of the heat sealing mechanism. When the heat sealing mechanism performs heat pressure sealing on the packaging bag to be heat sealed, the sensor can identify the displacement signal of the heat sealing mechanism and then convert the displacement signal into an image acquisition signal.

[0072] The controller is electrically connected to the conveying mechanism, the heat sealing mechanism and the sensor respectively, and is used to control the conveying mechanism to convey the packaging bags to be heat-sealed, and to control the heat sealing mechanism to perform heat-pressing edge sealing on the packaging bags to be heat-sealed; the controller also receives the image acquisition signal sent by the sensor, and sends a detection control signal according to the image acquisition signal.

[0073] The detection mechanism is arranged on the conveying line of the conveying mechanism. The detection mechanism is electrically connected to the controller, and is used to receive a detection control signal, and obtain a thermal image of another heat-sealed packaging bag adjacent to the packaging bag heat-sealed by the heat-sealing mechanism according to the detection control signal, and then send the thermal image to the controller, which compares and analyzes the thermal image and determines the heat sealing detection result.

[0074] In this embodiment, the conveying mechanism is specifically conveying rollers arranged at both ends of the heat sealing mechanism and the detection mechanism. The film packaging bag is made of two layers of composite plastic film, which are heat-sealed on three sides and then cut to form a packaging bag. The detection step is performed after heat sealing. The use of conveying rollers can enable the detection mechanism to perform unobstructed detection of the top and bottom surfaces of the packaging bag.

[0075] Reference Figure 2 , the conveying mechanism will Figure 2N packaging bags are transported along the direction F, and the heat sealing mechanism and the detection mechanism are sequentially arranged in the conveying direction F of the N packaging bags. During the transmission process, the heat sealing mechanism will sequentially heat seal the 1st, 2nd, 3rd, 4th...M-1th, Mth, M+1th...N-2th, N-1th until the Nth packaging bag is completed. When the M+1th packaging bag is heat sealed, the sensor identifies the displacement signal at the output end of the heat sealing mechanism, and then converts the displacement signal into an image acquisition signal and sends it to the controller. After receiving the image acquisition signal, the controller sends a detection control signal to the detection mechanism according to the image acquisition signal. After receiving the detection control signal, the detection mechanism obtains the thermal image of the Mth packaging bag, and then sends the thermal image to the controller. After receiving the thermal image, the controller compares and analyzes the image in at least a part of the area in the thermal image with the image in the same area in the set standard thermal image. The heat sealing effect of the packaging bag is judged as qualified or unqualified. If the parameters of the image in at least part of the area are within the predetermined deviation with the parameters of the image in the same area in the set standard thermal image, the heat sealing test result of the heat-sealed packaging bag is qualified, otherwise the heat sealing test result is unqualified. Therefore, by setting the sensor at the output end of the heat sealing mechanism, the displacement signal at the output end of the heat sealing mechanism during the hot pressing process is converted into an image acquisition signal, the detection mechanism acquires the thermal image of the packaging bag, and the controller analyzes and judges the thermal image to realize the detection of the heat sealing effect of the packaging bag, avoid the risk of missed detection, achieve the purpose of real-time online detection and identification of packaging bags with poor sealing, expand the identification range of heat sealing quality defects, and improve the accuracy of the heat sealing effect detection results of the packaging bag.

[0076] Furthermore, the controller includes a control module, an analysis module and a judgment module. The control module is electrically connected to the conveying mechanism, the heat sealing mechanism, the sensor and the detection mechanism respectively, and is used to control the conveying mechanism to convey the packaging bag to be heat-sealed, and to control the heat sealing mechanism to perform heat-pressing edge sealing on the packaging bag to be heat-sealed. The control module is also used to receive an image acquisition signal emitted by the sensor, and to send a detection control signal according to the image acquisition signal. When the control module controls the heat sealing mechanism to perform heat-pressing edge sealing on the packaging bag to be heat-sealed, the sensor converts the displacement signal at the output end of the heat sealing mechanism into an image acquisition signal and sends it to the control module, and the control module receives and sends a detection control signal to the detection mechanism according to the image acquisition signal, and controls the detection mechanism to acquire a thermal image of the packaging bag.

[0077] An analysis module, configured to receive a thermal image sent by a detection mechanism, and then extract the first temperature parameter of each pixel in at least a partial area of the thermal image, and the first shape distribution of all pixels in at least a partial area of the thermal image. Specifically, the detection mechanism receives a detection control signal sent by the control module, acquires a thermal image of the heat-sealed packaging bag, and sends it to the analysis module. The analysis module preprocesses the thermal image according to step S21, selects a partial area including the heat-sealing area, extracts the temperature value of each pixel in the image of this area as the first temperature parameter, and extracts the shape feature vector of the image of this area as the first shape distribution.

[0078] A judgment module, configured to compare the first temperature parameter with the standard temperature parameter of each pixel in the same area of the set standard thermal image, determine whether the difference between the first temperature parameter and the standard temperature parameter is within a predetermined temperature deviation, and compare the first shape distribution with the standard shape distribution of all pixels in the same area of the set standard thermal image, determine whether the similarity between the first shape distribution and the standard shape distribution reaches a predetermined shape similarity. If both are satisfied, it is determined that the heat-sealing detection result is qualified. Specifically, the judgment module obtains the standard temperature parameter T 0 and the standard shape distribution V 0 , calculates the temperature difference d T and the shape similarity d(V 1 , V 0 ), when the temperature difference -x < d T < +x, and the shape similarity d(V 1 , V 0 ) < y, the heat-sealing detection result is qualified; otherwise, the heat-sealing detection result is unqualified.

[0079] Furthermore, the controller further includes a storage module, which is connected to the analysis module. The storage module is used to store the standard thermal image, the predetermined temperature deviation (-x, +x), and the predetermined shape similarity y. The standard thermal image is selected from the thermal images stored in the analysis module. If the packaging bag that has been heat-sealed and whose thermal image has been collected is qualified after detecting the heat-sealing effect by traditional methods such as visual inspection and immersion in water, the thermal image of this packaging bag is stored in the storage module as the standard thermal image.

[0080] See also Fig. 9 , Fig. 9It is a stereoscopic diagram of the detection mechanism of the heat seal detection device in the embodiment. The detection mechanism includes a frame 1, a first infrared imaging camera 11 and a second infrared imaging camera 12. The first infrared imaging camera 11 and the second infrared imaging camera 12 are arranged on the frame 1 in the vertical direction and their lenses are arranged opposite to each other. The first infrared imaging camera 11 is arranged above the conveying line of the conveying mechanism and faces the upper end surface of the packaging bag, and is used to obtain a thermal image of the upper end surface seal of the packaging bag. The second infrared imaging camera 12 is arranged below the conveying line of the conveying mechanism and faces the lower end surface of the packaging bag, and is used to obtain a thermal image of the lower end surface seal of the packaging bag. In this embodiment, in order to improve the efficiency of the production line, two groups of first infrared imaging cameras 11 and two groups of second infrared imaging cameras 12 are specifically provided, and thermal images of two groups of packaging bags arranged side by side on the conveying rollers are collected at the same time.

[0081] Furthermore, the heat seal detection device also includes an alarm device, which is electrically connected to the control module. After the judgment module determines that the heat seal detection result of the packaging bag is unqualified, the control module will send an alarm signal to the alarm device, and the alarm device will send an audible and visual alarm after receiving the alarm signal to prompt the operator to pay attention to and adjust the relevant components and operating parameters in the bag making process in a timely manner.

[0082] Furthermore, the heat seal detection device also includes a rejection device, which is electrically connected to the control module. After the judgment module determines that the heat seal detection result of the packaging bag is unqualified, the control module will send a rejection signal to the rejection device, and the rejection device will reject the defective bag after receiving the rejection signal to avoid mixing with qualified packaging bags.

[0083] In summary, when the heat seal detection device in this embodiment is working, the conveying mechanism first conveys the packaging bag to be heat-sealed to the bottom of the heat sealing mechanism, and at the same time conveys the heat-sealed packaging bag adjacent to the packaging bag to be heat-sealed to between the first infrared camera 11 and the second infrared camera 12.

[0084] The output end of the heat sealing mechanism is pressed down to perform transverse or longitudinal heat sealing on the packaging bag to be heat-sealed below it, and the sensor is pressed down synchronously with the output end of the heat sealing mechanism. The sensor identifies the displacement signal of the output end of the heat sealing mechanism, and then converts the displacement signal into an image acquisition signal and sends it to the controller. The controller receives the image acquisition signal sent by the sensor, and sends a detection control signal according to the image acquisition signal. The first infrared camera 11 and the second infrared camera 12 respectively receive the detection control signal, and obtain the thermal image of the upper and lower seals of another heat-sealed packaging bag adjacent to the packaging bag heat-sealed by the heat sealing mechanism according to the detection control signal, and then sends the thermal image to the analysis module of the controller.

[0085] The analysis module receives the thermal image sent by the detection mechanism, and then extracts the first temperature parameter T of each pixel in at least a part of the thermal image. 1, and a first shape distribution V of all pixel points in the image within at least a partial region of the thermal image 1 .

[0086] The judgment module compares it with the standard temperature parameter T0 of each pixel point in the image within the same region of the standard thermal image and the standard shape distribution V0 of all pixel points, and then the judgment module judges whether the difference T between the first temperature parameter and the standard temperature parameter is within a predetermined temperature deviation (-x, +x), and judges the first shape distribution V 1 and the standard shape distribution V 0 of the similarity d(V 1 , V 0 ) is less than a predetermined shape similarity y.

[0087] When the temperature difference -x < d T < +x, and the shape similarity d(V 1 , V 0 ) < y, it is judged that the heat seal detection result is qualified, otherwise it is unqualified.

[0088] When the judgment module outputs that the heat seal detection result is unqualified, the control module sends an alarm signal to the alarm device. After receiving the alarm signal, the alarm device gives an audible and visual alarm. At the same time, the control module will send an ejection signal to the ejection device. After receiving the ejection signal, the ejection device ejects the unqualified packaging bag.

[0089] The above is only the embodiment of the present invention and is not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the scope of the claims of the present invention.

Claims

1. A heat seal detection method, characterized in that: The steps include: S1. Heat-pressing and edge-sealing the packaging bag to be heat-sealed; S2, obtaining a thermal image of the heat-sealed packaging bag; S3, comparing and analyzing the image in at least a partial area of ​​the acquired thermal image with the image in the same area of ​​a set standard thermal image; and S4. If the parameters of the image in at least a part of the area are within a predetermined deviation from the parameters of the image in the same area in the set standard thermal image, the heat sealing test result of the heat-sealed packaging bag is qualified, otherwise the heat sealing test result is unqualified.

2. The heat seal detection method according to claim 1, characterized in that: The step S3 comprises: S31, extracting a first temperature parameter of each pixel in the image in at least a partial area, and a first shape distribution of all pixels in the image in at least a partial area; S32, comparing the first temperature parameter and the first shape distribution with the standard temperature parameter of each pixel point and the standard shape distribution of all pixel points in the same area of ​​the standard thermal image; In step S4, if the difference between the first temperature parameter and the standard temperature parameter is within a predetermined temperature deviation, and the first shape distribution and the standard shape reach a predetermined shape similarity, the heat sealing test result is qualified, otherwise the heat sealing test result is unqualified.

3. The heat seal detection method according to claim 1 or 2, characterized in that: The step S2 includes obtaining a thermal image of the upper end seal and a thermal image of the lower end seal of the heat-sealed packaging bag; After step S4, the method further includes: S5. When the heat seal test result is unqualified, an alarm is issued and the unqualified heat-sealed packaging bags are rejected.

4. A heat seal detection method, characterized in that: The steps include: S1. While performing heat-pressing edge sealing on a packaging bag to be heat-sealed, obtain a thermal image of another heat-sealed packaging bag adjacent to the packaging bag to be heat-sealed; S2, comparing and analyzing the image in at least a partial area of ​​the acquired thermal image with the image in the same area of ​​a set standard thermal image; and S3. If the parameters of the image in at least a part of the area are within a predetermined deviation from the parameters of the image in the same area in the set standard thermal image, the heat sealing test result of the heat-sealed packaging bag is qualified, otherwise the heat sealing test result is unqualified.

5. The heat seal detection method according to claim 4, characterized in that: The step S2 comprises: S21, extracting a first temperature parameter of each pixel in the image in at least a partial area, and a first shape distribution of all pixels in the image in at least a partial area; S22, comparing the first temperature parameter and the first shape distribution with the standard temperature parameter of each pixel point and the standard shape distribution of all pixel points in the same area of ​​the standard thermal image; In step S3, if the difference between the first temperature parameter and the standard temperature parameter is within a predetermined temperature deviation, and the similarity between the first shape distribution and the standard shape distribution reaches a predetermined shape similarity, the heat sealing test result is qualified, otherwise the heat sealing test result is unqualified.

6. The heat seal detection method according to claim 4 or 5, characterized in that: The step S1 of acquiring a thermal image of another heat-sealed packaging bag adjacent to the packaging bag to be heat-sealed specifically includes: Acquire a thermal image of the upper end seal of another heat-sealed packaging bag adjacent to the packaging bag to be heat-sealed; and Acquire a thermal image of the seal of the lower end surface of another heat-sealed packaging bag adjacent to the packaging bag to be heat-sealed; After step S3, the method further includes: S4. When the heat seal test result is unqualified, an alarm is issued and the unqualified heat-sealed packaging bags are rejected.

7. A heat seal detection device, characterized in that: include: A conveying mechanism, used for conveying packaging bags to be heat-sealed; A heat sealing mechanism, arranged in the conveying direction of the conveying mechanism, for heat-pressing and edge-sealing the packaging bag to be heat-sealed; A sensor is provided at the output end of the heat sealing mechanism. When the heat sealing mechanism performs heat-pressing edge sealing on the packaging bag to be heat-sealed, the sensor can identify the displacement signal of the heat sealing mechanism and then convert the displacement signal into an image acquisition signal; a controller, electrically connected to the conveying mechanism, the heat sealing mechanism and the sensor, respectively, for controlling the conveying mechanism to convey the packaging bag to be heat-sealed, and for controlling the heat sealing mechanism to perform heat-pressing edge sealing on the packaging bag to be heat-sealed; the controller also receives an image acquisition signal from the sensor, and issues a detection control signal according to the image acquisition signal; a detection mechanism, arranged on the conveying line of the conveying mechanism, electrically connected to the controller, for receiving the detection control signal, and acquiring a thermal image of another heat-sealed packaging bag adjacent to the packaging bag heat-sealed by the heat-sealing mechanism according to the detection control signal, and then sending the thermal image to the controller; Among them, after receiving the thermal image, the controller compares and analyzes the image in at least a partial area of ​​the thermal image with the image in the same area of ​​a set standard thermal image; if the parameters of the image in at least a partial area are within a predetermined deviation from the parameters of the image in the same area of ​​the set standard thermal image, the heat sealing test result of the heat-sealed packaging bag is qualified, otherwise the heat sealing test result is unqualified.

8. The heat seal detection device according to claim 7, characterized in that: The controller comprises: A control module is electrically connected to the conveying mechanism, the heat sealing mechanism, and the sensor, respectively, and is used to control the conveying mechanism to convey the packaging bag to be heat-sealed, and to control the heat sealing mechanism to perform heat-pressing edge sealing on the packaging bag to be heat-sealed; and is also used to receive an image acquisition signal from the sensor, and to issue a detection control signal according to the image acquisition signal; an analysis module, configured to receive the thermal image sent by the detection mechanism, and then extract a first temperature parameter of each pixel in at least a portion of the thermal image, and a first shape distribution of all pixels in at least a portion of the thermal image; and The judgment module is used to compare the first temperature parameter with the standard temperature parameter of each pixel point in the same area of ​​the image in the set standard thermal image, to judge whether the difference between the first temperature parameter and the standard temperature parameter is within a predetermined temperature deviation, and to compare the first shape distribution with the standard shape distribution of all pixel points in the same area of ​​the set standard thermal image, to judge whether the similarity between the first shape distribution and the standard shape distribution reaches a predetermined shape similarity. If both are true, the heat sealing test result is judged to be qualified.

9. The heat seal detection device according to claim 8, characterized in that: The controller further comprises a storage module connected to the analysis module, wherein the storage module is used to store a standard thermal image, a predetermined temperature deviation and a predetermined shape similarity.

10. The heat seal detection device according to claim 7, characterized in that: The detection mechanism includes: A first infrared imaging camera is disposed above the conveying line of the conveying mechanism, facing the upper end surface of the packaging bag, and is used to obtain a thermal image of the seal of the upper end surface of the packaging bag; and The second infrared imaging camera is arranged below the conveying line of the conveying mechanism, facing the lower end surface of the packaging bag, and is used to obtain a thermal image of the seal of the lower end surface of the packaging bag.

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