A method for accurately measuring tobacco leaf surface area

Abstract

A method for accurately measuring tobacco leaf area, characterized in that it comprises the following steps: 1) initial measurement of leaf area, 2) extraction of regular tobacco sheets, 3) separation of cuticle layer, 4) measurement of cuticle layer area, and 5) correction of leaf area. The principle of the present application is that the area of the cuticle layer of tobacco is equal to the area of the tobacco leaf, and the cuticle layer of the tobacco sample to be measured is separated by enzymatic method to measure the area of the flat and wrinkle-free cuticle layer, and then the leaf area is corrected according to the difference between the cuticle layer area and the tobacco sheet leaf area. Compared with the existing method for measuring the area of tobacco leaves, the method of the present application has the advantages that the influence of factors such as wrinkles and unevenness on the surface of tobacco leaves on the measurement results of the leaf area is eliminated, and the accuracy of the measurement results of the leaf area of tobacco is significantly improved.

Description

Technical Field

[0001] This invention belongs to the field of tobacco raw material research, and specifically relates to a method for accurately measuring the surface area of ​​tobacco leaves. Background Technology

[0002] The cigarette manufacturing process involves continuous changes in the shape, size, moisture content, and temperature of tobacco leaves. Leaf surface area is a crucial indicator of tobacco quality, closely related not only to the rate of moisture absorption and desiccation but also to the length of the cut tobacco shreds. Tobacco leaves with larger surface areas require longer processing times and higher processing intensities during rehydration and storage to achieve the desired moisture content and uniformity. The cut tobacco shreds also require appropriate breakage to ensure uniformity and stability during rolling. Conversely, smaller leaf surfaces require shorter processing times and lower processing intensities. Therefore, accurately measuring the leaf surface area is essential for guiding the setting of technical parameters in cigarette manufacturing processes.

[0003] Existing methods for measuring the surface area of ​​tobacco leaves mostly rely on computer technology, primarily image processing and hyperspectral analysis. Chinese patent CN114739326A (202210505490.5) provides a method and system for measuring the area of ​​flue-cured tobacco leaves. It mainly uses image processing to acquire tobacco leaf images under a single light source, determines the layer information of the tobacco leaf based on the pixel values ​​of the images, and then calculates the area corresponding to each layer based on the number of pixels and the number of layers, thereby calculating the tobacco leaf area. Chinese patent CN103543107A (201310499083.9) provides an intelligent tobacco leaf grading system and method based on machine vision and hyperspectral technology. It applies high-speed image processing technology to process the acquired tobacco leaf images, obtaining the geometric shape features, color features, texture features, and internal quality features of the tobacco leaves in one step, achieving intelligent grading of tobacco leaves and improving grading speed.

[0004] Existing methods can provide the surface area measurement results of tobacco leaves. However, since tobacco leaves used in cigarette production and processing have undergone initial or re-drying, the surface of fresh tobacco leaves is uneven and wrinkled after water loss. Measurement methods such as image or hyperspectral analysis cannot reflect the surface area of ​​the wrinkled areas of tobacco leaves. Therefore, accurate measurement of the surface area of ​​tobacco leaves requires eliminating the measurement error caused by the wrinkles in the tobacco leaves. Summary of the Invention

[0005] This invention addresses the shortcomings of existing methods by providing a precise method for measuring the surface area of ​​tobacco leaves. This method can eliminate measurement errors caused by wrinkles on the surface of tobacco leaves and improve the accuracy of leaf area measurement results.

[0006] The present invention provides a method for accurately measuring the surface area of ​​tobacco leaves, which specifically includes the following steps:

[0007] (1) Initial determination of leaf area: After collecting image information of the sample and the reference object under the same field of view under the light source, the ratio of the area occupied by the sample in the image to the area occupied by the reference object in the image is calculated by the program. Since the area corresponding to the reference object is known, the initial leaf area S0 of the tobacco leaf can be calculated.

[0008] (2) Regular tobacco leaf sampling: The tobacco leaves are laid flat and samples are taken by randomly punching holes on the surface of the tobacco leaves using a puncher. For whole tobacco leaves, samples are taken randomly from the leaf tip to the leaf base, with the main vein of the tobacco leaf as the axis of symmetry. For tobacco flakes, samples are taken by randomly punching holes using a puncher.

[0009] (3) Cuticle separation: The regular tobacco leaves extracted by punching holes are soaked in an enzymatic hydrolysate to separate the cuticle of the tobacco leaves, and the cuticle is washed with ultrapure water;

[0010] Specifically, the process involves immersing regularly shaped tobacco sheets, extracted through perforation, in an enzymatic hydrolysate and placing them in a constant temperature and humidity chamber at 22°C and 60% relative humidity for 5–36 hours to achieve the separation of the tobacco sheet's cuticle. During the hydrolysis process, the container holding the tobacco sheets and the enzymatic hydrolysate is placed in a shaker and shaken at a frequency of 80–100 rpm to accelerate the separation of the cuticle.

[0011] Next, the cuticle layer of the tobacco leaves, separated by enzymatic hydrolysis and shaking, was transferred to ultrapure water and purified using an ultrasonic cleaner to remove other cell tissues adhering to the surface of the cuticle layer. The ultrasonic cleaner had a power of 360W and a cleaning time of 10-15 seconds.

[0012] (4) Cuticle area measurement: The method of cuticle area measurement is the same as that of the initial leaf area measurement in step (1), and both are completed by image processing to obtain the cuticle area S1.

[0013] (5) Leaf area correction: Based on the dimensions of the regular tobacco leaves obtained by the punch, calculate the leaf area S2 of the regular tobacco leaves. Based on the cuticle area S1 and the tobacco leaf area S2, calculate the leaf area correction coefficient K. The calculation method is as follows:

[0014]

[0015] The final leaf area S of the tobacco leaf is calculated based on the correction coefficient and the initial leaf area S0. The calculation method is as follows:

[0016]

[0017] The punch described in step (2) of this invention can be a circular punch, or a punch of various regular shapes such as square or rhombus. The size of the punch is set according to the size of the tobacco sheet.

[0018] The number of perforations for sampling in step (2) of this invention is set according to the size of the tobacco sheet. For a whole tobacco leaf, the number of perforations is 10 to 50; for tobacco sheets, the number of perforations is 5 to 20.

[0019] The enzymatic hydrolysate mentioned in step (3) of the present invention is a single pectinase solution or an enzyme solution prepared by mixing pectinase and cellulase (volume ratio 1:1).

[0020] The principle of this invention is based on the fact that the area of ​​the cuticle of tobacco leaves is equal to the actual leaf surface area. An enzymatic hydrolysis method is used to separate the cuticle of regular tobacco leaves obtained by drilling holes in the sample to be tested, so as to realize the measurement of the area of ​​the flat, wrinkle-free cuticle. Then, the leaf surface area is corrected based on the difference between the cuticle area S1 and the leaf surface area S2 of the regular tobacco leaf.

[0021] Compared with existing methods for measuring the surface area of ​​tobacco leaves, the method of this invention has the advantage of eliminating the influence of factors such as wrinkles and unevenness on the surface of tobacco leaves on the measurement results, thus significantly improving the accuracy of the measurement results. Attached Figure Description

[0022] Figure 1 Scanning electron microscope image of flue-cured tobacco leaves (two sites);

[0023] Figure 2 Scanning electron microscope image of the cuticle of flue-cured tobacco leaves in vitro (two sites). Detailed Implementation

[0024] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand the present invention, but it is not intended to limit the present invention.

[0025] The main steps of the technical solution adopted in this invention are as follows:

[0026] (1) Initial determination of leaf area: After collecting image information of the sample and the reference object under the same field of view under the light source, the ratio of the area occupied by the sample in the image to the area occupied by the reference object in the image is calculated by the program. Since the area corresponding to the reference object is known, the initial leaf area S0 of the tobacco leaf can be calculated.

[0027] (2) Regular tobacco leaf sampling: Lay the tobacco leaves flat and use a punch to randomly punch holes on the surface of the tobacco leaves to take samples. The punch can be round, or it can be square, rhomboid or other regular shapes. The size of the punch is set according to the size of the tobacco leaves.

[0028] For whole tobacco leaves, samples are randomly taken from the leaf tip to the leaf base, with the main vein as the axis of symmetry. The number of holes for sampling is 10 to 50. For tobacco flakes, a hole punch is used to randomly punch holes for sampling. The number of holes for sampling is 5 to 20, and the specific number is set according to the size of the tobacco flakes.

[0029] (3) Cuticle separation: The regularly shaped tobacco sheets extracted by perforation are soaked in a single pectinase or an enzymatic hydrolysate prepared by mixing pectinase and cellulase. The enzymatic hydrolysis process is carried out in a constant temperature and humidity chamber at 22°C and 60% relative humidity for 5-36 hours to achieve the separation of the cuticle of the tobacco sheets. During the enzymatic hydrolysis process, the container containing the tobacco sheets and the enzymatic hydrolysate is placed in a shaker and shaken at a frequency of 80-100 rpm to accelerate the separation of the cuticle.

[0030] Next, the cuticle layer of the tobacco leaves, separated by enzymatic hydrolysis and shaking, was transferred to ultrapure water and purified using an ultrasonic cleaner to remove other cell tissues adhering to the surface of the cuticle layer. The ultrasonic cleaner had a power of 360W and a cleaning time of 10-15 seconds.

[0031] (4) Cuticle area measurement: The initial measurement of cuticle area is the same as that of tobacco leaf surface area, which is completed by image processing to obtain cuticle area S1.

[0032] (5) Leaf area correction: Based on the dimensions of the regular tobacco leaves obtained by the punch, calculate the leaf area S2 of the regular tobacco leaves. Based on the cuticle area S1 and the tobacco leaf area S2, calculate the leaf area correction coefficient K. The calculation method is as follows:

[0033]

[0034] The final leaf area S of the tobacco leaf is calculated based on the correction coefficient and the initial leaf area S0. The calculation method is as follows:

[0035]

[0036] Example 1

[0037] Three grades of primary flue-cured tobacco leaves (B2F, C2F, and X2F) from Xiangyun County, Dali, Yunnan Province, were selected, and their leaf surface area was determined using the method of this invention.

[0038] (1) Initial determination of leaf area: The flue-cured tobacco leaves were laid flat, and the surface image information of the tobacco leaves was acquired using an A7A20CG9 industrial camera manufactured by Huarui Technology. The camera resolution was 4096×3000, the image sensor was IMX304, the pixel depth was 12bit, the matching image acquisition software was MV viewer, the built-in attribute exposure was 11000lx·s, the brightness was 90cd / m², the saturation was 100%, the test environment temperature was 25℃, and the relative humidity was 5%~10%. Then, the reference object (a rectangular block of 2.54cm×7.62cm) was photographed under the same field of view. The initial leaf area S0 of B2F, C2F, and X2F tobacco leaves was measured to be 456.84cm². 2 634.50cm 2 266.49cm 2 .

[0039] (2) Regular tobacco leaf sampling: Use a circular punch with a diameter of 1.5cm to punch holes in the tobacco leaf to take samples. Take 5 points at equal intervals on the same side of the leaf tip, 10 points at equal intervals in the middle of the leaf, and 5 points at equal intervals in the base of the leaf, with the main vein of the tobacco leaf being symmetrical. A total of 40 points are taken from the whole tobacco leaf sample. Be careful to avoid the branch veins.

[0040] (3) Cuticle separation: The regularly shaped tobacco sheets extracted by perforation were soaked in an enzymatic hydrolysate prepared by diluting pectinase and cellulase (volume ratio 1:1) 10 times. The cellulase and pectinase were provided by Novozymes, with pectinase activity of 10968 PECTU / g and cellulase activity of 700 EGU / g. The enzymatic hydrolysis process was carried out in a constant temperature and humidity chamber at 22℃ and 60% relative humidity for 18 hours to achieve the separation of the cuticle of the tobacco sheets. During the enzymatic hydrolysis process, the container containing the tobacco sheets and the enzymatic hydrolysate was placed in a shaker and shaken at a frequency of 90 rpm to accelerate the separation of the cuticle.

[0041] Next, the cuticle layer of the tobacco leaves, separated by enzymatic hydrolysis and shaking, was transferred to ultrapure water and purified using an ultrasonic cleaner to remove other cell tissues adhering to the surface of the cuticle layer. The ultrasonic cleaner had a power of 360W and a cleaning time of 10 seconds.

[0042] Appendix Figure 1 , Figure 2 The images show scanning electron microscope (SEM) images of flue-cured tobacco leaves and cuticles separated from the leaves. It is clear from the two images that there is a stark contrast in appearance between the flue-cured tobacco leaves and the detached cuticles. The SEM image of the flue-cured tobacco leaves shows a large difference in brightness, with bright areas being high and dark areas being low, indicating that the surface of the flue-cured tobacco leaves is uneven and has obvious wrinkles. In contrast, the SEM image of the detached cuticles shows uniform brightness, and the surface of the detached cuticles is clearly smooth and flat.

[0043] (4) Determination of stratum corneum area: The separated stratum corneum is transferred and spread flat on a glass slide (2.54cm×7.62cm), and the stratum corneum area S1 of three grades B2F, C2F and X2F is determined by the method in step (1).

[0044] (5) Leaf area correction: Based on the dimensions of the regular tobacco leaves obtained by the punch, calculate the leaf area S2 of the regular tobacco leaves. Based on the cuticle area S1 and the tobacco leaf area S2, calculate the leaf area correction coefficient K. The calculation method is as follows:

[0045]

[0046] The calculation results of the correction coefficients for 40 regular tobacco leaves are shown in Table 1. As can be seen from Table 1, the correction coefficient K for the 40 samples measured for B2F tobacco leaves ranged from 1.0223 to 1.3389, with an average value of 1.1618; for the 40 samples measured for C2F tobacco leaves, the correction coefficient K ranged from 1.0590 to 1.6479, with an average value of 1.2778; and for the 40 samples measured for X2F tobacco leaves, the correction coefficient K ranged from 1.0012 to 1.5763, with an average value of 1.1057.

[0047] The final leaf area S of the tobacco leaf is calculated based on the correction coefficient and the initial leaf area S0. The calculation method is as follows:

[0048]

[0049] The final leaf area calculation results for B2F, C2F, and X2F grade tobacco leaves are as follows:

[0050] B2F: S=1.1618×456.84=530.76cm 2 ;

[0051] C2F: S=1.2778×634.50=810.76cm 2 ;

[0052] X2F: S=1.1057×266.49=294.66cm 2 .

[0053] Table 1 Correction coefficients for leaf area of ​​flue-cured tobacco leaves

[0054] sample <![CDATA[B2F]]> <![CDATA[C2F]]> <![CDATA[X2F]]> 1 1.0640 1.4252 1.0218 2 1.1548 1.3341 1.2098 3 1.2521 1.0944 1.0330 4 1.0698 1.2965 1.0425 5 1.0772 1.2576 1.0678 6 1.2133 1.0590 1.2359 7 1.1613 1.1508 1.1577 8 1.1907 1.2400 1.5763 9 1.1740 1.1930 1.0130 10 1.2432 1.3232 1.1494 11 1.3094 1.4392 1.2044 12 1.0978 1.2403 1.0420 13 1.2865 1.2879 1.0730 14 1.0255 1.2806 1.1744 15 1.2120 1.2553 1.0817 16 1.1790 1.1504 1.0918 17 1.3389 1.1406 1.0708 18 1.0423 1.3484 1.1134 19 1.0420 1.3170 1.0142 20 1.3279 1.3068 1.0109 21 1.0252 1.1421 1.0012 22 1.2691 1.2322 1.2216 23 1.0411 1.1190 1.0760 24 1.0354 1.2813 1.2445 25 1.1667 1.1892 1.0152 26 1.1297 1.2967 1.0063 27 1.1192 1.3814 1.0062 28 1.1838 1.2010 1.0609 29 1.0223 1.1804 1.0505 30 1.2100 1.2971 1.0113 31 1.1831 1.3536 1.0255 32 1.2360 1.3617 1.1655 33 1.1912 1.6479 1.1559 34 1.1055 1.1433 1.0123 35 1.1880 1.3126 1.0046 36 1.1028 1.3172 1.1662 37 1.0728 1.2806 1.4785 38 1.2835 1.6041 1.0331 39 1.3170 1.3968 1.0825 40 1.1289 1.2310 1.0252 K 1.1618 1.2778 1.1057

[0055] Example 2

[0056] The leaf area of ​​flue-cured tobacco flakes from Luoyang, Henan Province, grade C3F, was determined using the method of this invention.

[0057] (1) Initial determination of leaf area: The flue-cured tobacco leaves were laid flat, and the surface image information of the tobacco leaves was acquired using an A7A20CG9 industrial camera manufactured by Huarui Technology. The camera resolution was 4096×3000, the image sensor was IMX304, the pixel depth was 12bit, the image acquisition software was MV viewer, the built-in attribute exposure was 11000lx·s, the brightness was 90cd / m², the saturation was 100%, the test environment temperature was 25℃, and the relative humidity was 5%~10%. Then, the reference object (a rectangular block of 2.54cm×7.62cm) was photographed under the same field of view. The initial leaf area S0 of the tobacco leaf was measured to be 15cm² through image processing. 2 .

[0058] (2) Regular tobacco leaf sampling: Use a circular punch with a diameter of 1.5cm to randomly punch holes in the tobacco leaf for sampling. Take 5 points for each tobacco leaf sample, and be careful to avoid the branch veins.

[0059] (3) Cuticle separation: The regularly shaped tobacco sheets extracted by perforation were soaked in an enzymatic hydrolysate prepared by mixing pectinase and cellulase diluted 8 times. The cellulase and pectinase were provided by Novozymes, with pectinase activity of 10968 PECTU / g and cellulase activity of 700 EGU / g. The enzymatic hydrolysis process was carried out in a constant temperature and humidity chamber at 22℃ and 60% relative humidity for 18 hours to achieve the separation of the cuticle of the tobacco sheets. During the enzymatic hydrolysis process, the container containing the tobacco sheets and the enzymatic hydrolysate was placed in a shaker and shaken at a frequency of 90 rpm to accelerate the separation of the cuticle.

[0060] Next, the cuticle layer of the tobacco leaves, separated by enzymatic hydrolysis and shaking, was transferred to ultrapure water and purified using an ultrasonic cleaner to remove other cell tissues adhering to the surface of the cuticle layer. The ultrasonic cleaner had a power of 360W and a cleaning time of 10 seconds.

[0061] (4) Determination of cuticle area: The separated cuticle was transferred and spread flat on a glass slide (2.54cm×7.62cm), and the cuticle area S1 of the regular smoke sheet was determined by the method in step one.

[0062] (5) Leaf area correction: Based on the dimensions of the regular tobacco leaves obtained by the punch, calculate the leaf area S2 of the regular tobacco leaves. Based on the cuticle area S1 and the tobacco leaf area S2, calculate the leaf area correction coefficient K. The calculation method is as follows:

[0063]

[0064] The correction coefficient K for the five samples measured in tobacco leaf samples was 1.2223.

[0065] The final leaf area S of the tobacco is calculated based on the correction coefficient K and the initial leaf area S0. The calculation method is as follows:

[0066]

[0067] The final calculated leaf area of ​​the tobacco leaf is as follows:

[0068] S = 1.2223 × 15 = 18.33 cm 2

[0069] Example 3

[0070] The leaf surface area of ​​the first-cured tobacco leaves from Chuxiong, Yunnan, grade C3F, was determined using the method of this invention.

[0071] (1) Initial determination of leaf area: The flue-cured tobacco leaves were laid flat, and the surface image information of the tobacco leaves was acquired using an A7A20CG9 industrial camera manufactured by Huarui Technology. The camera resolution was 4096×3000, the image sensor was IMX304, the pixel depth was 12bit, the accompanying image acquisition software was MV viewer, the built-in attribute exposure was 11000lx·s, the brightness was 90cd / m², the saturation was 100%, the test environment temperature was 25℃, and the relative humidity was 5%~10%. Then, the reference object (a rectangular block of 2.54cm×7.62cm) was photographed under the same field of view. The initial leaf area S0 of the tobacco leaves was measured to be 460cm² through image processing. 2 .

[0072] (2) Regular tobacco leaf sampling: Use a circular punch with a diameter of 1.5cm to punch holes in the tobacco leaf to take samples. Take 5 points at equal intervals on the same side of the leaf tip, 10 points at equal intervals in the middle of the leaf, and 5 points at equal intervals in the base of the leaf, with the main vein of the tobacco leaf being symmetrical. A total of 40 points are taken from the whole tobacco leaf sample. Be careful to avoid the branch veins.

[0073] (3) Cuticle separation: The regularly shaped tobacco sheets extracted by perforation were soaked in an enzymatic hydrolysate prepared solely with pectinase, with an enzyme activity of 10968 PECTU / g. The enzymatic hydrolysis process was carried out in a constant temperature and humidity chamber at 22℃ and 60% relative humidity for 24 hours to achieve the separation of the cuticle from the tobacco sheets. During the enzymatic hydrolysis process, the container containing the tobacco sheets and the enzymatic hydrolysate was placed in a shaker and shaken at a frequency of 90 rpm to accelerate the separation of the cuticle.

[0074] Next, the cuticle layer of the tobacco leaves, separated by enzymatic hydrolysis and shaking, was transferred to ultrapure water and purified using an ultrasonic cleaner to remove other cell tissues adhering to the surface of the cuticle layer. The ultrasonic cleaner had a power of 360W and a cleaning time of 10 seconds.

[0075] (4) Determination of cuticle area: The separated cuticle was transferred and spread flat on a glass slide (2.54cm×7.62cm), and the cuticle area S1 of the regular smoke sheet was determined by the method in step one.

[0076] (5) Leaf area correction: Based on the dimensions of the regular tobacco leaves obtained by the punch, calculate the leaf area S2 of the regular tobacco leaves. Based on the cuticle area S1 and the tobacco leaf area S2, calculate the leaf area correction coefficient K. The calculation method is as follows:

[0077]

[0078] The correction factor K for the 40 regular tobacco sheets is 1.2590.

[0079] The final leaf area S of the tobacco leaf is calculated based on the correction coefficient and the initial leaf area S0. The calculation method is as follows:

[0080]

[0081] The final calculated leaf area of ​​the tobacco leaves is as follows:

[0082] S = 1.2590 × 460 = 579.14 cm 2 .

Claims

1. A method for accurately measuring the surface area of ​​tobacco leaves, characterized in that: Includes the following steps: (1) Initial determination of leaf area: After collecting image information of the sample and the reference object under the same field of view under the light source, the ratio of the area occupied by the sample in the image to the area occupied by the reference object in the image is calculated by the program. Since the area corresponding to the reference object is known, the initial leaf area S0 of the tobacco leaf can be calculated. (2) Regular tobacco leaf extraction: Lay the tobacco leaves flat and use a punch to randomly punch holes on the surface of the tobacco leaves to take samples; (3) Cuticle separation: The regular tobacco sheets extracted by drilling are soaked in an enzymatic hydrolysate to separate the cuticle of the tobacco sheets, and the cuticle is washed with ultrapure water. (4) Cuticle area measurement: The method for measuring the cuticle area is the same as that for the initial measurement of the leaf surface area in step (1), and both are completed by image processing to obtain the cuticle area S1. (5) Leaf area correction: Based on the regular tobacco leaf size obtained by the punch, calculate the leaf area S2 of the regular tobacco leaf. Based on the cuticle area S1 and the tobacco leaf area S2, calculate the leaf area correction coefficient K. The calculation method is as follows: ； The final leaf area S of the tobacco leaf is calculated based on the correction coefficient and the initial leaf area S0. The calculation method is as follows: 。 2. The method for accurately measuring the surface area of ​​tobacco leaves according to claim 1, characterized in that: In step (2), for a whole tobacco leaf, samples are randomly taken from the leaf tip to the leaf base, with the main vein of the tobacco leaf as the axis of symmetry; for tobacco flakes, a punch is used to randomly punch holes for sampling.

3. The method for accurately measuring the surface area of ​​tobacco leaves according to claim 1, characterized in that: In step (3), the specific conditions for enzymatic hydrolysis are: place the container in a constant temperature and humidity room with a temperature of 22 ℃ and a relative humidity of 60 % for enzymatic hydrolysis for 5~36 h; during the enzymatic hydrolysis process, place the container containing the tobacco flakes and the enzymatic hydrolysate in a shaker and shake it at a frequency of 80~100 rpm to accelerate the separation of the stratum corneum.

4. The method for accurately measuring the surface area of ​​tobacco leaves according to claim 1, characterized in that: Step (3) The cleaning process is as follows: The cuticle of the tobacco leaves separated by enzymatic hydrolysis and oscillation is transferred to ultrapure water and cleaned and purified by ultrasonic cleaning machine to remove other cell tissues adhering to the surface of the cuticle.

5. The method for accurately measuring the surface area of ​​tobacco leaves according to claim 4, characterized in that: The ultrasonic cleaner has a power of 360 W and a cleaning time of 10~15 s.

6. The method for accurately measuring the surface area of ​​tobacco leaves according to claim 1, characterized in that: In step (2), the punch is a round punch, or a square or rhomboid punch; the punching area of ​​the punch is set according to the size of the tobacco sheet.

7. The method for accurately measuring the surface area of ​​tobacco leaves according to claim 1, characterized in that: In step (2), the number of perforations for sampling of tobacco leaves is set according to the size of the tobacco leaves. For whole tobacco leaves, the number of perforations for sampling is 10 to 50; for tobacco leaves, the number of perforations for sampling is 5 to 20.

8. The method for accurately measuring the surface area of ​​tobacco leaves according to claim 1, characterized in that: In step (3), the enzymatic hydrolysate is a single pectinase solution or an enzyme solution prepared by mixing pectinase and cellulase.

9. The method for accurately measuring the surface area of ​​tobacco leaves according to claim 1, characterized in that: In step (1), an A7A20CG9 industrial camera manufactured by Huarui Technology is used to acquire image information of the tobacco leaf surface. The camera resolution is 4096×3000, the photosensitive chip is IMX304, the pixel depth is 12bit, the matching image acquisition software is MV viewer, the built-in attribute exposure is 11000lx·s, the brightness is 90cd / m², and the saturation is 100%.

Images