An online visual inspection device, method, and storage medium for cigarette circumference

Abstract

This invention discloses an online visual inspection device, method, and storage medium for cigarette circumference. The method includes: step S1, acquiring images of the cigarette in the horizontal and vertical directions; step S2, acquiring the circumferential height of the longitudinal section and the circumferential width of the transverse section of the cigarette based on an image recognition algorithm; step S3, if the circumferential height of the longitudinal section and the circumferential width of the transverse section of the cigarette are the same, then the circumferential value of the cigarette is obtained through a circumferential calculation formula; otherwise, it is determined whether the cigarette is shaking. If there is no shaking, the circumferential value of the cigarette is calculated through the width of the cigarette splice paper and the width of the cigarette overlap; if there is shaking, the circumferential value of the cigarette is calculated through a fitting function and the width of the cigarette overlap. This method can effectively eliminate detection errors caused by cigarette deformation and jumping, and can quickly acquire the cigarette diameter and the overlap glue width online, meeting the needs of high-speed online production and effectively improving cigarette quality.

Description

Technical Field

[0001] This invention relates to the field of cigarette inspection technology, specifically to an online visual inspection device, method, and storage medium for the circumference of cigarettes. Background Technology

[0002] The cigarette circumference is an important physical indicator of cigarettes, affecting their smoking quality. Domestic cigarette factories mostly use medium-speed rolling equipment such as ZJ17, ZJ118, ZJ19, and KDF2. Due to the high production speed of these units, unstable operation of the cigarette pack conveyor belt, deviations in the position of the pressure plates and the cigarette tongue, uneven glue application at the cigarette pack and cigarette paper overlap, and the introduction of impurities and foreign matter, the circumference of the cigarette fluctuates significantly during the cigarette forming process. If the cigarette circumference exceeds the standard value of ±0.20mm, it is considered to be out of standard. Currently, the method for detecting the cigarette circumference is: after the cigarette is rolled, the width of the cigarette cross-section is determined by a photoelectric detection switch. Because the cigarette pack may be squeezed by the soldering iron during actual production, the circumference may not change, but the cross-section may become an ellipse within the permissible range of the process standard. Figure 1 If only an ellipse in one direction is measured, it is very easy to cause data misinterpretation, so the measurement results of this method are inaccurate.

[0003] Another detection method is offline testing, where operators randomly sample cigarettes and measure their circumference using instruments such as a comprehensive testing instrument or a cigarette measuring pan. Offline testing cannot detect fluctuations in cigarette circumference in a timely manner, making real-time quality tracking impossible and easily leading to defects in cigarette products, severely hindering the improvement of cigarette physical indicators. Therefore, there is an urgent need for a high-precision, online, real-time method for detecting cigarette circumference. Summary of the Invention

[0004] To address the aforementioned issues, the inventors have provided an online method for detecting the circumference of cigarettes. This method, based on visual inspection technology, can detect the circumference of cigarettes in real time, accurately, and efficiently, replacing existing photoelectric circumference detection and offline sampling methods. This helps improve the detection accuracy of cigarette circumference, ensure product quality, and reduce the probability of quality defects.

[0005] According to a first aspect, the present invention provides an online visual inspection method for the circumference of a cigarette, comprising the following steps:

[0006] Step S1: Acquire images of the cigarette in the horizontal and vertical directions;

[0007] Step S2: Based on the image recognition algorithm, obtain the circumferential height of the longitudinal section of the cigarette from the image of the cigarette in the horizontal direction, and obtain the circumferential width of the transverse section of the cigarette from the image of the cigarette in the vertical direction;

[0008] Step S3: If the circumferential height of the longitudinal section of the cigarette is the same as the circumferential width of the transverse section of the cigarette, then the circumferential value of the cigarette can be obtained by using the circumferential calculation formula.

[0009] Conversely, the width of the cigarette splice is obtained, and the laser point in the splice image is used as a reference point to determine whether the cigarette is wobbling. If there is no wobbling, the circumference of the cigarette is calculated by the width of the cigarette packing paper and the width of the cigarette splice. If there is wobbling, the circumference of the cigarette is calculated by the fitting function and the width of the cigarette splice.

[0010] Further, the laser point is rectangular, and the distances between the two sides of the laser point and the overlapping edge on the same side are a and c, respectively. In step S3, the step of determining whether the cigarette is swaying includes:

[0011] Based on image recognition algorithms, determine a and c;

[0012] If a = c, then the cigarette does not wobble; otherwise, the cigarette does wobble.

[0013] Furthermore, if the cigarette does not move, then

[0014] Cigarette circumference = cigarette tipping paper width - measured overlap width;

[0015] If the cigarette moves, the actual overlap width of the cigarette is determined based on the fitted function. At this time, the cigarette circumference value = cigarette tipping paper width - actual overlap width.

[0016] Furthermore, methods for determining the fitting function include:

[0017] Using standard-sized cigarettes as calibration cigarettes, and with the focal length of the vertical vision detection unit remaining constant, the overlap of the calibration cigarettes is photographed every 0.1 mm to obtain an image of the overlap of the calibration cigarettes.

[0018] The distance between the laser sensor and the calibrated cigarette is obtained from the laser sensor at each time a photo is taken; based on the image recognition algorithm, the width of the calibrated cigarette overlap is obtained from the image of the overlap of the calibrated cigarette each time.

[0019] The width of the cigarette closure and the distance between the laser sensor and the calibrated cigarette are fitted together to obtain a fitting function for the measured cigarette closure width and the distance between the laser sensor and the calibrated cigarette. The measured cigarette closure width is fitted together with the actual closure width to obtain a fitting function for the cigarette closure width and the actual closure width.

[0020] According to a second aspect, the present invention also provides a computer-readable storage medium having a computer program stored thereon, the computer program being executable by a processor to implement the steps of the method described above.

[0021] According to a third aspect, the present invention further provides an online visual inspection device for the circumference of cigarettes, comprising:

[0022] support;

[0023] A horizontal visual detection unit, mounted on the bracket, is used to acquire images of the cigarette in the horizontal direction;

[0024] A vertical vision detection unit, mounted on the bracket, is used to acquire images of the cigarette in the vertical direction.

[0025] A laser sensor is used to send a laser to the cigarette splice opening, so that a laser dot appears on the splice opening and the width of the laser dot is greater than the width of the splice opening.

[0026] The host computer is communicatively connected to the horizontal vision detection unit, the vertical vision detection unit, and the laser sensor, and has a built-in computer-readable storage medium as described in claim 5.

[0027] Furthermore, both the horizontal and vertical visual inspection units are equipped with lighting modules for illuminating the cigarettes.

[0028] Furthermore, the bracket is ring-shaped with an opening at its lower part. One end of the opening is equipped with a micro-air dust removal module, which is used to remove debris in the detection area.

[0029] Furthermore, the air outlet of the micro-wind dust removal module is tilted towards the inside of the bracket at an angle of 45°.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] The device and method provided by this invention employ vertical and horizontal vision sensors. The vertical vision sensor mainly measures the width of the cigarette paper overlap and the circumference of the cigarette's transverse cross-section; the horizontal vision sensor mainly measures the circumference of the cigarette's longitudinal cross-section. By introducing a laser sensor to determine whether the cigarette is wobbling, detection errors caused by cigarette deformation and jumping can be effectively eliminated. The device and method can quickly collect the cigarette diameter and the overlap adhesive width online, meeting the needs of online high-speed production. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the cross-section of a cigarette.

[0033] Figure 2 This is a schematic diagram of the online visual inspection device for cigarette circumference in Example 1;

[0034] Figure 3 This is a front view of the online visual inspection device for cigarette circumference in Example 1;

[0035] Figure 4 This is a diagram showing the usage status of the online visual inspection device for cigarette circumference in Example 1;

[0036] Figure 5 This is a schematic diagram of the cigarette closure in this invention;

[0037] Figure 6 This is a schematic diagram of the laser dot and the cigarette overlap imaging in this invention;

[0038] Figure 7 A flowchart of the online visual inspection method for cigarette circumference provided by the present invention;

[0039] Figure 8 This is a fitted curve of the measurement of the cigarette overlap width and the distance between the laser sensor and the cigarette in Example 2;

[0040] Figure 9 This is a graph showing the ratio of the measured cigarette overlap width to the actual overlap width in Example 2.

[0041] 1-Bracket; 11-Opening; 2-Vertical vision inspection unit; 3-Horizontal vision inspection unit; 4-Laser sensor; 51-Vertical illumination module; 52-Horizontal illumination module; 6-Micro-wind dust removal module; 7-Cigarette stick. Detailed Implementation

[0042] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings.

[0043] Example 1

[0044] like Figure 2 As shown, the present invention provides an online visual inspection device for the circumference of cigarettes, comprising: a bracket 1 and a vertical visual inspection unit 2, a horizontal visual inspection unit 3, a laser sensor 4 and a micro-wind dust removal module 6 disposed on the bracket 1, wherein the bracket 1 is connected to the cigarette rolling machine and is located at the front end of the cigarette gun 8, and its axis is opposite to the center hole of the cigarette gun 8.

[0045] The lens of the vertical vision inspection unit 2 is equipped with a vertical illumination module 51, and the lens of the horizontal vision inspection unit 3 is equipped with a horizontal illumination module 52. Both the vertical and horizontal illumination modules 51 and 52 are preferably LED matrix modules, with a through-hole in the center to accommodate the lens. The use of linear LEDs provides excellent directionality and ensures sufficient brightness for image acquisition. The interior of the bracket 1, the lens portions of the vertical and horizontal vision inspection units 2 and 3, and the vertical and horizontal illumination modules 51 and 52 all have a matte black surface to reduce light interference from diffuse reflection on the measurement and imaging of the inspection units.

[0046] Furthermore, such as Figure 3As shown, the bracket 1 is ring-shaped with an opening 11 at its bottom. The micro-wind dust removal module 6 is located at one end of the opening 11, and its air outlet is tilted towards the inside of the bracket 1 at an angle of 45° so that the blown air can flow along the inner wall of the bracket 1 to form a vortex. After the air passes through the vertical visual detection unit 2 and the horizontal visual detection unit 3 in sequence, it flows out from the other end of the opening 11. In this way, the flowing air is used to remove cigarette tobacco scraps and paper dust in the detection area to ensure the accuracy of the images acquired by the two visual detection units.

[0047] Specifically, in this embodiment, the vertical vision detection unit 2 and the horizontal vision detection unit 3 employ industrial vision cameras. The vertical vision detection unit 2 is located on the top of the bracket 1, and its front end is equipped with a laser sensor 4. The laser sensor 4 is perpendicular to the cigarette 7, and the overlap of the cigarette 7 is located at the top of the cigarette 7. The laser emitted by the laser sensor 4 is directed at the overlap of the cigarette 7, so that a laser dot appears on the overlap, and the width of the laser dot is greater than the width of the overlap. Preferably, the size of the laser dot is 3mm × 3mm, which can directly use the side length data of a square, avoiding data errors caused by the secondary calculation of the diameter length of a circular laser dot. The imaging diagram of the cigarette overlap is shown below. Figure 5-6 As shown. The horizontal visual inspection unit 3 is located on the side of the bracket 1, and its lens is equipped with a horizontal illumination module 52, which illuminates the side of the cigarette horizontally.

[0048] Specifically, such as Figure 7 As shown, the cigarette circumference detection includes the following steps:

[0049] Step S1: The vertical vision detection unit 2 acquires an image of the cigarette in the vertical direction, which includes the laser point and the overlap.

[0050] Vertical vision detection unit 3 acquires images of the cigarette in the horizontal direction.

[0051] Step S2: Based on existing image recognition algorithms, obtain the circumferential height of the longitudinal cross-section of the cigarette from the image of the cigarette in the horizontal direction, and obtain the circumferential width of the transverse cross-section of the cigarette from the image of the cigarette in the vertical direction.

[0052] Step S3: If the circumferential height of the longitudinal section of the cigarette and the circumferential width of the transverse section of the cigarette are the same, then the cigarette is considered to be a perfect circle. The circumference value of the cigarette is obtained by using the circumference calculation formula C = πd, where d is the circumferential height of the longitudinal section of the cigarette or the circumferential width of the transverse section of the cigarette.

[0053] Conversely, the width 'b' of the cigarette overlap is obtained, and the laser point in the overlap image is used as a reference point to determine whether the cigarette is wobbling. Specifically, since the overlap of the cigarette is significantly different from other locations, appearing whiter, edge detection methods in image processing can be used to obtain the position coordinates of the edge at the overlap. By converting these position coordinates into actual physical dimensions, the overlap width 'b' can be obtained. See "Method for Measuring the Width of Cigarette Segment Overlap Based on Image Processing" in *Information Technology and Network Security*, Vol. 37, No. 7, 2018, pp. 95-97, for more details; it will not be elaborated upon here.

[0054] The process of determining whether a cigarette is wobbling is as follows: Based on existing image recognition algorithms, determine the lengths 'a' and 'c' that extend beyond the overlap on both sides of the laser point. If the lengths 'a' and 'c' extend beyond the overlap on both sides of the laser point, then the cigarette is not wobbling; otherwise, the cigarette is wobbling.

[0055] If there is no shaking, the cigarette circumference value C is calculated as: cigarette tipping paper width - overlap width b. If there is shaking, the cigarette circumference value C is calculated using a fitting function and the cigarette overlap width b.

[0056] If the cigarette is wobbling, the cigarette circumference value is determined based on a fitting function of the distance between the cigarette and the laser sensor and the width of the cigarette rim.

[0057] The method for determining the fitting function is as follows:

[0058] Using standard-sized cigarettes as calibration cigarettes, and with the focal length of the vertical vision detection unit 2 remaining constant, the overlap of the calibration cigarettes is photographed every 0.1 mm to obtain an image of the overlap of the calibration cigarettes.

[0059] The distance between the laser sensor 4 and the calibrated cigarette is obtained from the laser sensor 4 at each time a photo is taken; based on the existing image recognition algorithm, the width of the calibrated cigarette overlap is obtained from the image of the calibrated cigarette overlap for each time.

[0060] The width of the cigarette overlap and the distance between the laser sensor and the cigarette are fitted to the data for each calibration to obtain a fitting function. Data fitting can be performed using methods such as least squares fitting, polynomial fitting, or custom function fitting; the specific process is not limited here.

[0061] Furthermore, if both the measured overlap width *b* and the cigarette circumference value *C* simultaneously meet the error requirements of the corresponding process standard data for the cigarette, then the cigarette circumference is deemed to meet the process standard and is considered a qualified cigarette. If either data does not meet the corresponding process standard data for the cigarette, then the cigarette circumference is deemed to not meet the process standard and is considered a substandard cigarette. In this case, an alarm will be triggered to alert the staff.

[0062] Example 2

[0063] The cigarette tipping paper width is 26.50 mm, and the standard circumference width of the cigarette is 24.20 mm, therefore the standard cigarette overlap width is 2.30 mm. With a fixed camera focal length, the relationship between the distance between the laser sensor 4 and the calibrated cigarette and the image size is shown in Table 1 below. The fitting curves for determining the cigarette overlap width and the distance between the laser sensor and the cigarette are shown below. Figure 8 As shown in the figure, the curve representing the ratio of the cigarette overlap width to the actual overlap width is as follows. Figure 9 As shown, the fitted curve is y = 2E - 12x 2 -1x+52.3. The fitting formula for the measured overlap width and the actual overlap width is Y=0.4348x-8E-14.

[0064] Table 1

[0065]

[0066] If the cigarette is not moving, the distance a = c = 0.35 mm between the two edges of the laser point and the edge of the overlap on the same side. If the cigarette is moving, then a ≠ c, indicating that the cigarette is moving. This suggests that the overlap width in the image is inaccurate, and directly using this data will lead to a deviation in the measurement of the cigarette's circumference. For example, if the distance measured by the laser sensor is 49.96 mm, the overlap width measured in the image is 2.34 mm, but the actual overlap width is 2.30 mm.

[0067] The actual cigarette overlap width can be determined using the following method:

[0068] The laser rangefinder 4 can measure the distance y between the cigarette and the laser sensor. The curve y = 2E-12x is fitted between the distance between the cigarette and the laser sensor and the measured overlap width. 2 -1x+52.3 can be used to obtain the measured overlap width x. Then, the Y value can be obtained by Y=0.4348x-8E-14. The x / Y value is the actual overlap width of the cigarette. The circumference value C of the cigarette is the width of the cigarette packing paper minus the actual overlap width of the cigarette, which can effectively eliminate the error in the circumference value caused by the shaking of the cigarette.

[0069] Example 3

[0070] To verify the accuracy of an online visual inspection device for cigarette circumference, we conducted an offline measurement of the produced cigarettes and compared the circumference data obtained by the original photoelectric tube measurement method with the data in Table 2 below.

[0071] Table 2

[0072]

[0073] Existing methods for determining cigarette circumference using photoelectric detection switches often result in inaccurate measurements. This is because the cigarette is compressed by the soldering iron, causing the circumference length to remain unchanged, but the cross-section to become an ellipse within the permissible range of process standards. Consequently, the measured diameter value is often overestimated. When the same cigarette is measured offline, the circumference value calculated using the formula is consistently too large. In contrast, the circumference data measured by the visual inspection device described in this application shows significantly less error and higher accuracy compared to measurements taken using a measuring tray and integrated testing platform.

[0074] The above examples illustrate the present invention only to aid in understanding it and are not intended to limit the scope of the invention. Those skilled in the art can make various simple deductions, modifications, or substitutions based on the principles of this invention.

Claims

1. A method for on-line visual inspection of the circumference of a cigarette, characterized in that, The method comprises the following steps: Step S1: acquiring images of the cigarette in horizontal and vertical directions; Step S2: based on an image recognition algorithm, acquiring the circumferential height of the longitudinal section of the cigarette from the image of the cigarette in the horizontal direction, and acquiring the circumferential width of the transverse section of the cigarette from the image of the cigarette in the vertical direction; Step S3: if the circumferential height of the longitudinal section of the cigarette and the circumferential width of the transverse section of the cigarette are the same, the circumferential value of the cigarette is obtained through a circumferential calculation formula; Otherwise, the overlap width of the cigarette is acquired, and the laser point in the overlap image is taken as a reference point to determine whether the cigarette is shaking, if not, the circumferential value of the cigarette is calculated through the overlap width of the cigarette and the tipping paper width of the cigarette; if yes, the circumferential value of the cigarette is calculated through a fitting function and the overlap width of the cigarette.

2. The method of claim 1, wherein, The laser point is rectangular, and the distances between the two side edges of the laser point and the overlap edges on the same side are a and c respectively, and in step S3, the step of determining whether the cigarette is shaking comprises: Based on the image recognition algorithm, a and c are determined; If a=c, the cigarette is not shaking, otherwise, the cigarette is shaking.

3. The method of claim 1 or 2, wherein, If the cigarette is not shaking, The circumferential value of the cigarette = the tipping paper width of the cigarette - the measured overlap width; If the cigarette is shaking, the actual overlap width of the cigarette is determined based on the fitting function, and the circumferential value of the cigarette = the tipping paper width of the cigarette - the actual overlap width of the cigarette.

4. The method of claim 1, wherein, The determination method of the fitting function comprises: A standard size cigarette is taken as a calibration cigarette, and under the condition that the focal length of the vertical visual detection unit is unchanged, the calibration cigarette overlap is photographed every 0.1 mm, and the calibration cigarette overlap image is obtained; The distance between the laser sensor and the calibration cigarette measured by the laser sensor at each time of photographing is acquired; based on the image recognition algorithm, the width of the calibration cigarette overlap at each time is acquired from the calibration cigarette overlap image; The width of the calibration cigarette overlap at each time and the distance between the laser sensor and the calibration cigarette are data fitted to obtain the fitting function of the measured cigarette overlap width and the distance between the laser sensor and the calibration cigarette; the measured cigarette overlap width and the actual overlap width are data fitted to obtain the fitting function of the cigarette overlap width and the actual overlap width.

5. A computer-readable storage medium having stored thereon a computer program, characterized in that, The computer program can be executed by the processor to realize the steps of the method as claimed in any one of claims 1-4.

6. A device for on-line visual inspection of the circumference of a cigarette, characterized in that, It comprises: a support; a horizontal visual detection unit arranged on the support and used for acquiring images of the cigarette in the horizontal direction; a vertical visual detection unit arranged on the support and used for acquiring images of the cigarette in the vertical direction; a laser sensor used for sending laser to the cigarette overlap to make a laser point appear on the overlap, and the width of the laser point is greater than the overlap width; a host computer in communication connection with the horizontal visual detection unit, the vertical visual detection unit and the laser sensor, and the host computer is internally provided with the computer readable storage medium as claimed in claim 5.

7. The cigarette circumference on-line visual inspection device according to claim 6, wherein, The horizontal visual detection unit and the vertical visual detection unit are both provided with an illumination module used for illuminating the cigarette.

8. The cigarette circumference on-line visual inspection device according to claim 6 or 7, characterized in that, The support is annular, and the lower part of the support is provided with an opening, one end of the opening is provided with a slight wind dust removal module, and the slight wind dust removal module is used for removing sundries in the detection area.

9. The cigarette circumference on-line visual inspection device according to claim 8, wherein, The air outlet of the micro-wind dust removal module is inclined towards the inside of the support, and the inclination angle is 45°.

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