Tobacco leaf porosity classification method
By combining the light transmittance, gram-weight ratio and width-length ratio, the subjective deviation and equipment complexity in the measurement of tobacco leaf looseness are solved, and the rapid and accurate classification of tobacco leaf density is achieved, and the measurement efficiency and accuracy are improved.
Patent Information
- Application Number
- CN202411573929.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-06
- Publication Date
- 2025-02-25
AI Technical Summary
The prior art has subjective deviations and complex equipment dependence in the measurement of tobacco leaf looseness, and is sensitive to changes in environmental conditions, resulting in inconsistency and errors in the measurement results.
The tobacco leaf density classification method combining light transmittance, grams-weight ratio and width-length ratio is used to quickly and accurately evaluate the density of tobacco leaf by combining optical measurements and physical indicators.
It realizes the rapid and accurate classification of the density of tobacco leaves, reduces subjective deviations and equipment complexity, improves the efficiency and accuracy of measurement, and is suitable for different environmental conditions and various types of tobacco leaves.
Smart Images
Figure CN119510680A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field and specifically relates to a method for classifying the looseness of tobacco leaves Background Art
[0002] During tobacco processing and quality control, the looseness of tobacco leaves is one of the key factors that determine the burning rate, smoke fluidity and final taste of cigarettes. The looseness of tobacco leaves directly affects the ignition performance of tobacco, the amount of smoke produced, and the consumer's smoking experience. Too loose tobacco leaves may cause cigarettes to burn too quickly and produce insufficient smoke, while too dense tobacco leaves may cause difficulty in ignition and poor smoke flow, ultimately affecting the quality and market acceptance of cigarettes.
[0003] In the traditional measurement scope of tobacco leaf looseness, the mainstream means often rely on the subjective judgment of senior operators or quantitative analysis with the help of precision mechanical measuring devices. These methods can reveal the loose state of tobacco leaves to some extent, but they have certain limitations. The problem is that the subjective evaluation method is highly dependent on the personal experience and intuition of the evaluator, which inevitably introduces significant subjective bias and difficulty in replicability, thereby weakening the consistency and reliability of the evaluation results. On the other hand, although mechanical measurement technology strives to be objective, it often needs to be equipped with complex experimental devices, the operation process is lengthy and requires high operating skills; more importantly, such methods are easily disturbed by subtle changes in environmental conditions, such as temperature and humidity, during implementation, thereby significantly increasing the risk of measurement errors. Therefore, based on the predecessors, a method that can quickly and accurately classify the looseness of tobacco leaves is innovatively proposed, which has important practical significance and broad application prospects. The ideal measurement method should have the characteristics of high efficiency, accuracy, good repeatability, etc., and can work stably under different environmental conditions and be applicable to various types of tobacco leaves. For this reason, the present invention is proposed. Summary of the invention
[0004] The present invention provides a tobacco leaf density classification method combining light transmittance, gram-to-weight ratio and width-to-length ratio. The method combines optical measurement with physical indicators to quickly and accurately evaluate the tobacco leaf density, and is suitable for classification measurement in tobacco leaf quality control.
[0005] In order to achieve the above object, the present invention provides the following technical solutions:
[0006] A method for classifying tobacco leaf density comprises the following steps: (1) measuring a light transmittance index T of tobacco leaves, and classifying the tobacco leaf density according to the size of the light transmittance index T; (2) measuring physical indicators of tobacco leaves, and classifying the tobacco leaf density according to the size of the physical indicators; (3) performing a comprehensive analysis based on the light transmittance index T and the physical indicators of the tobacco leaves, and finally determining the classification of the tobacco leaf density.
[0007] Preferably, in step (1), according to the size of the light transmittance index T, the classification standard of the tobacco leaf density is as follows: when the light transmittance T > 0.58, it is "sparse"; when the light transmittance T < 0.52, it is "dense"; when the light transmittance 0.52 ≤ T ≤ 0.58, it is "average"; in step (2), the physical indexes of the tobacco leaf are the width-to-length ratio and the grammage ratio. According to the size of the width-to-length ratio and the grammage ratio, the classification standard of the tobacco leaf density is as follows: when the width-to-length ratio > 0.37 or the grammage ratio < 0.010, it is "sparse"; when the width-to-length ratio < 0.25 or the grammage ratio > 0.012, it is "dense"; when 0.25 ≤ width-to-length ratio ≤ 0.37 or 0.010 ≤ grammage ratio ≤ 0.012, it is "average".
[0008] Preferably, in step (3), a comprehensive analysis is carried out according to the light transmittance index T and the physical indexes of the tobacco leaf, and the classification of the tobacco leaf density is finally determined according to the following steps:
[0009] (31) When T ≥ 0.62, it is directly classified as "sparse"; when T ≤ 0.495, it is directly classified as "dense"; in these two cases, the classification of the two physical indexes is not considered;
[0010] (32) When 0.58 < T < 0.62, at this time the light transmittance index is "sparse", and the physical indexes need to be considered. The classification is as follows: (321) When one physical index is "sparse" and the other physical index is "average" or "dense", the final classification is "sparse"; (322) When the physical indexes are "average, dense" or "dense, average", the final classification is "average"; (323) When the two physical indexes are "dense, dense", the final classification is "average";
[0011] (33) When 0.495 < T < 0.52, at this time the light transmittance index is "dense", and the physical indexes need to be considered. The classification is as follows: (331) When one physical index is "dense" and the other physical index is "average" or "sparse", the final classification is "dense"; (332) When the physical indexes are "sparse, average" or "average, sparse", the final classification is "average"; (333) When the two physical indexes are "sparse, sparse", the final classification is "average";
[0012] (34) When 0.52 ≤ T ≤ 0.58, at this time the light transmittance index is "average", and when one of the physical indexes is "average", that is, when one of the physical indexes is the same as the light transmittance index and is "average", the final classification is "average"; if
[0013] (35) When 0.52≤T≤0.58, the transmittance index is "general", but when neither of the two physical indicators is "general", the two physical indicators are inconsistent with the transmittance index, and the following classification shall prevail: (351) When the physical indicator is "sparse, sparse", the final classification is "sparse"; (352) When the physical indicator is "dense, dense", the final classification is "dense"; (353) When the physical indicator is "dense, sparse" or "sparse, dense", the final classification is "general".
[0014] Preferably, the step (1) of measuring the light transmittance index T of the tobacco leaf comprises: selecting no less than three measuring points on the dried tobacco leaf; using a light intensity meter to measure the light intensity I of each measuring point passing through the tobacco leaf; t，i and initial light intensity I0, calculate the transmittance of each measurement point Then the transmittance index T is obtained by calculating the average transmittance of multiple measurement points.
[0015] Preferably, the steps for measuring the gram-to-weight ratio and the width-to-length ratio of the tobacco leaves in step (2) are: (21) measuring the maximum width and maximum length of the dried tobacco leaves and calculating the width-to-length ratio; (22) weighing the mass (g) of the dried tobacco leaf sample and measuring its surface area (cm 2 ), calculate the mass to surface area ratio, i.e. gram to weight ratio.
[0016] Preferably, the light intensity meter includes a white light LED light source and a photosensitive probe, and the light source power is not less than 5 watts; the distance between the light source and the surface of the tobacco leaf sample is fixed at 10 cm; the measurement process is carried out in a light-controlled environment, such as a darkroom or a closed space.
[0017] Preferably, when measuring tobacco leaf indicators, it is necessary to ensure that the surface of the tobacco leaf is flat, has no obvious wrinkles, and is dry. The dryness standard is 8-12 wt % of water.
[0018] Preferably, there are three measuring points, and the three measuring points are selected as follows: the first measuring point is the center of the leaf vein (50% of the leaf vein length) and the center between the leaf vein and the leaf edge, the second measuring point is the tip of the leaf (about 10% of the leaf vein length from the tip of the leaf) and the center between the leaf vein and the leaf edge, and the third measuring point is the petiole end (about 10% of the leaf vein length from the petiole) and the center between the leaf vein and the leaf edge. This selection can ensure that the three measurements are representative.
[0019] Beneficial effects of the present invention:
[0020] The tobacco leaf density classification method of the present invention can quickly and accurately classify tobacco leaf density through comprehensive evaluation of light transmittance, physical index gram-to-weight ratio and width-to-length ratio. The method of the present invention is easy to operate and quick to measure, avoids the error of traditional subjective judgment methods, reduces the requirements of complex equipment and operation procedures, and greatly improves the efficiency and accuracy of measurement. By combining the light transmittance index T and physical indicators, it is possible to scientifically deal with the difference between light transmittance and physical indicators, ensure the stability and consistency of classification results, and is very suitable for large-scale control of tobacco leaf quality in industrial production.
[0021] The prior art generally uses transmittance alone to classify the density of tobacco leaves. Although transmittance can directly reflect the optical properties of tobacco leaves and then evaluate the density of the fiber structure, the actual density of tobacco leaves cannot be fully evaluated by transmittance alone, because when the physical properties such as tobacco leaf thickness and fiber arrangement vary greatly, the transmittance result may be affected by the local structure of the sample, resulting in deviations in the evaluation results. The present invention introduces physical indicators of tobacco leaves for the first time as indicators for evaluating the fiber structure of tobacco leaves. In the present invention, the physical indicators are gram-to-weight ratio and width-to-length ratio; gram-to-weight ratio (mass / area) refers to the mass per unit area of tobacco leaves, in g / cm2, which is used to evaluate the density characteristics of tobacco leaves; width-to-length ratio refers to the ratio of the maximum width to the maximum length of tobacco leaves, which is used to reflect the shape characteristics of tobacco leaves. The present invention introduces physical indicators gram-to-weight ratio and width-to-length ratio, which can supplement the deficiencies of transmittance evaluation; the present invention can more accurately reflect the actual density of tobacco leaves through the combination of transmittance indicators and physical indicators, and realize a more scientific classification of tobacco leaf density. The classification method of the present invention is generally welcomed by enterprises. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 Schematic diagram of the selection of three measurement points for the tobacco leaf transmittance index T of the present invention. DETAILED DESCRIPTION
[0023] The present invention will be further described below in conjunction with the accompanying drawings and examples. It should be understood by those skilled in the art that the examples are only intended to help understand the present invention and should not be considered as limitations of the present invention. Unless otherwise specified, the meanings of all technical terms and scientific terms used in this specification are the same as those generally understood by those skilled in the art to which the present invention belongs. However, in the event of a conflict, the present specification including the definitions shall prevail.
[0024] A method for classifying tobacco leaf density comprises the following steps: (1) measuring a light transmittance index T of tobacco leaves, and classifying the tobacco leaf density according to the size of the light transmittance index T; (2) measuring physical indicators of tobacco leaves, and classifying the tobacco leaf density according to the size of the physical indicators; (3) performing a comprehensive analysis based on the light transmittance index T and the physical indicators of the tobacco leaves, and finally determining the classification of the tobacco leaf density.
[0025] Among them, in step (1), according to the magnitude of the light transmittance index T, the classification standard for the leaf density is as follows: when the light transmittance T > 0.58, it is "sparse"; when the light transmittance T < 0.52, it is "dense"; when the light transmittance 0.52 ≤ T ≤ 0.58, it is "general"; in step (2), the physical indexes of the tobacco leaves are the width-to-length ratio and the weight ratio. According to the magnitude of the width-to-length ratio and the weight ratio, the classification standard for the leaf density is as follows: when the width-to-length ratio > 0.37 or the weight ratio < 0.010, it is "sparse"; when the width-to-length ratio < 0.25 or the weight ratio > 0.012, it is "dense"; when 0.25 ≤ width-to-length ratio ≤ 0.37 or 0.010 ≤ weight ratio ≤ 0.012, it is "general".
[0026] Among them, in step (3), based on the comprehensive analysis of the light transmittance index T and the physical indexes of the tobacco leaves, the classification of the leaf density is finally determined according to the following steps:
[0027] (31) When T ≥ 0.62, it is directly classified as "sparse"; when T ≤ 0.495, it is directly classified as "dense"; in these two cases, the classification of the two physical indexes is not considered;
[0028] (32) When 0.58 < T < 0.62, at this time the light transmittance index is "sparse", and the physical indexes need to be considered. The classification is based on the following: (321) When one of the physical indexes is "sparse" and the other physical index is "general" or "dense", the final classification is "sparse"; (322) When the physical indexes are "general, dense" or "dense, general", the final classification is "general"; (323) When the two physical indexes are "dense, dense", the final classification is "general";
[0029] (33) When 0.495 < T < 0.52, at this time the light transmittance index is "dense", and the physical indexes need to be considered. The classification is based on the following: (331) When one of the physical indexes is "dense" and the other physical index is "general" or "sparse", the final classification is "dense"; (332) When the physical indexes are "sparse, general" or "general, sparse", the final classification is "general"; (333) When the two physical indexes are "sparse, sparse", the final classification is "general";
[0030] (34) When 0.52 ≤ T ≤ 0.58, at this time the light transmittance index is "general", and when one of the physical indexes is "general", that is, when one of the physical indexes is the same as the light transmittance index and is "general", the final classification is "general";
[0031] (35) When 0.52≤T≤0.58, the transmittance index is "general", but neither of the two physical indicators is "general", the physical indicator is inconsistent with the transmittance index, and the following classification shall prevail: (351) When the physical indicator is "sparse, sparse", the final classification is "sparse"; (352) When the physical indicator is "dense, dense", the final classification is "dense"; (353) When the physical indicator is "dense, sparse" or "sparse, dense", the final classification is "general".
[0032] The step (1) of measuring the light transmittance index T of the tobacco leaf comprises: selecting no less than three measuring points on the dried tobacco leaf; using a light intensity meter to measure the light intensity I of each measuring point passing through the tobacco leaf; t，i and initial light intensity I0, calculate the transmittance of each measurement point Then the transmittance index T is obtained by calculating the average transmittance of multiple measurement points.
[0033] The steps for measuring the gram-to-weight ratio and the width-to-length ratio of the tobacco leaves in step (2) are as follows: (21) measuring the maximum width and maximum length of the dried tobacco leaves and calculating the width-to-length ratio; (22) weighing the mass (g) of the dried tobacco leaf sample and measuring its surface area (cm 2 ), calculate the mass to surface area ratio, i.e. gram to weight ratio.
[0034] The light intensity meter includes a white light LED light source and a photosensitive probe, and the light source power is not less than 5 watts; the distance between the light source and the surface of the tobacco leaf sample is fixed at 10 cm; the measurement process is carried out in a light-controlled environment, such as a darkroom or a closed space.
[0035] When measuring tobacco leaf indicators, it is necessary to ensure that the surface is flat, without obvious wrinkles and dry. The dryness standard is 8-12wt% water content; tobacco leaves that are too dry or too wet will affect the accuracy of the measurement.
[0036] There are three measuring points, and the three measuring points are selected as follows: the first measuring point is the center of the leaf vein (50% of the leaf vein length) and the center between the leaf vein and the edge of the leaf blade; the second measuring point is the tip of the leaf (about 10% of the leaf vein length from the tip of the leaf) and the center between the leaf vein and the edge of the leaf blade; the third measuring point is the petiole end (about 10% of the leaf vein length from the petiole) and the center between the leaf vein and the edge of the leaf blade; Figure 1 shown.
[0037] Example
[0038] To separate the density of a type of tobacco leaves of a certain enterprise, the steps are as follows:
[0039] S1: Select tobacco leaves with strong representativeness and good appearance as samples. The samples should be dried immediately after collection, and the water content should be kept at about 10wt% to avoid moisture affecting the measurement of transmittance; the dried tobacco leaves should maintain their original shape without obvious deformation or warping. The thickness of each sample should be measured to ensure that its thickness is within 1 mm;
[0040] S2: Use a white LED lamp with a high color rendering index (CRI>90) to ensure that the spectral composition of the light source is close to natural light; the light source power should be large enough (power above 5W) to ensure that the light can effectively penetrate the tobacco leaf sample; fix the light source at a height of 10cm from the surface of the tobacco leaf sample, and the light source is perpendicular to the sample surface; use a fixed bracket and a distance measuring tool to ensure that the distance between the light source and the sample remains consistent in each measurement. Before each measurement, calibrate the light intensity meter to ensure that its reading is accurate; use a standard light source for calibration, and record the calibrated reading as a reference benchmark;
[0041] S3: On each tobacco leaf, three measuring points are set on the vein axis from the tip to the petiole, evenly distributed from the tip along the middle vein to the petiole, and at the center between the vein and the edge of the tobacco leaf. The first test point is located at the top of the tobacco leaf, about 10% of the total length from the tip; the second test point is located near the middle of the tobacco leaf, about 50% of the total length of the tobacco leaf; the third test point is located near the petiole, about 10% of the total length of the petiole, such as Figure 1 As shown; the light intensity I passing through the tobacco leaves is measured at these three locations using a light intensity meter t , and record the light intensity I0 when it does not pass through the tobacco leaves;
[0042] S4: Calculate the light transmittance of each measurement point based on the data of that point Then calculate the average transmittance of the three points The average of the three measurement results is taken as the final transmittance T. If the difference between the three measurement results exceeds 5%, it is necessary to re-measure or replace the sample to reduce the influence of accidental factors on the measurement results.
[0043] S5: To ensure the accuracy of the measurement results, multiple measurements should be performed at each measuring point, and the average value should be taken as the transmittance value T of that point. i .
[0044] S6: Prepare physical index measurement tools to measure gram-to-weight ratio and width-to-length ratio;
[0045] S7: Weigh the mass of the dried tobacco leaf sample, measure its surface area, and calculate the gram-to-weight ratio (tobacco leaf mass / surface area, g / cm 2) to evaluate the density of tobacco leaf fibers; the grammage ratio is measured using a balance with an accuracy of 0.001 g, and the surface area can be measured using image analysis software;
[0046] S8: Use a measuring ruler to measure the maximum width and maximum length of the tobacco leaf, and calculate the width-to-length ratio (maximum width / maximum length) to evaluate the shape characteristics of the tobacco leaf; keep the tobacco leaf flat during measurement to reduce measurement errors;
[0047] S9: Based on the light transmittance T calculated according to the foregoing formula, conduct numerical comparison to obtain the looseness density grade of the sample; conduct unified measurement and classification on the tobacco leaf samples of the same batch to ensure the consistency of the results; according to the calculated light transmittance T, divide the looseness degree of the tobacco leaf into three grades: when the light transmittance T > 0.58, it is "loose"; when the light transmittance T < 0.52, it is "dense"; when the light transmittance 0.52 ≤ T ≤ 0.58, it is "general"; according to the size of the width-to-length ratio and the grammage ratio, the classification standard for the looseness density of the tobacco leaf is: when the width-to-length ratio > 0.37 or the grammage ratio < 0.010, it is "loose"; when the width-to-length ratio < 0.25 or the grammage ratio > 0.012, it is "dense"; when 0.25 ≤ width-to-length ratio ≤ 0.37 or 0.010 ≤ grammage ratio ≤ 0.012, it is "general".
[0048] S10: Conduct comprehensive analysis for the final classification:
[0049] S101: Based on the light transmittance as the main basis, when T ≥ 0.62, directly classify it as "loose"; when T ≤ 0.495, directly classify it as "dense"; in these two cases, do not consider the classification of the two physical indicators;
[0050] S102: When 0.58 < T < 0.62, at this time the light transmittance index is "loose", and the physical indicators need to be considered. The classification is as follows: if one of the physical indicators is "loose" and the other physical indicator is "general" or "dense", the final classification is "loose"; if the physical indicators are "general, dense" or "dense, general", then the final classification is "general"; if the two physical indicators are "dense, dense", the final classification is "general";
[0051] S103: When 0.495 < T < 0.52, at this time the light transmittance index is "dense", and the physical indicators need to be considered. The classification is as follows: if one of the physical indicators is "dense" and the other physical indicator is "general" or "loose", the final classification is "dense"; if the physical indicators are "loose, general" or "general, loose", then the final classification is "general"; if the two physical indicators are "loose, loose", the final classification is "general";
[0052] S104: When 0.52≤T≤0.58, the transmittance index is "normal". If one of the physical indicators is "normal", that is, one of the physical indicators and the transmittance index are consistent with "normal", the final classification is "normal".
[0053] S105: When 0.52≤T≤0.58, the transmittance index is "general", but neither of the two physical indicators is "general", the physical indicator is inconsistent with the transmittance index, and the following classification shall prevail: if the physical indicator is "sparse, sparse", the final classification is "sparse"; if the physical indicator is "dense, dense", the final classification is "dense"; if the physical indicator is "dense, sparse" or "sparse, dense", the final classification is "general".
[0054] S11: The transmittance, physical index and corresponding density of each tobacco leaf sample are classified and recorded in a data table, as shown in the following table.
[0055] The density classification of the 30 tobacco leaf samples in this embodiment is as follows:
[0056] sample Gram-to-weight ratio Gram-to-weight ratio classification Aspect Ratio Aspect Ratio Classification Light transmittance Transmittance classification Final classification Sample 1 0.0093 sparse 0.248 dense 0.611 sparse sparse Sample 2 0.0112 generally 0.441 sparse 0.598 sparse sparse Sample 3 0.0124 dense 0.345 generally 0.498 dense dense Sample 4 0.0123 dense 0.405 sparse 0.497 dense dense Sample 5 0.0119 generally 0.316 generally 0.523 generally generally Sample 6 0.0093 sparse 0.355 generally 0.575 generally generally Sample 7 0.0108 generally 0.382 sparse 0.571 generally generally Sample 8 0.0125 dense 0.368 generally 0.542 generally generally Sample 9 0.0101 generally 0.241 dense 0.528 generally generally Sample 10 0.0112 generally 0.216 dense 0.589 sparse generally Sample 11 0.0166 dense 0.368 generally 0.591 sparse generally Sample 12 0.0162 dense 0.246 dense 0.602 sparse generally Sample 13 0.0131 dense 0.319 generally 0.511 dense generally Sample 14 0.0105 generally 0.439 sparse 0.502 dense dense Sample 15 0.0099 sparse 0.371 sparse 0.508 dense generally Sample 16 0.0093 sparse 0.372 sparse 0.533 generally sparse Sample 17 0.0132 dense 0.375 dense 0.522 generally dense Sample 18 0.0122 dense 0.498 sparse 0.538 generally generally Sample 19 0.0094 sparse 0.374 dense 0.578 generally generally Sample 20 0.0116 generally 0.352 generally 0.416 dense dense Sample 21 0.0124 dense 0.368 generally 0.493 dense dense Sample 22 0.0101 generally 0.487 sparse 0.639 sparse sparse Sample 23 0.0096 sparse 0.445 sparse 0.743 sparse sparse Sample 24 0.0093 sparse 0.355 generally 0.575 generally generally Sample 25 0.0119 generally 0.352 generally 0.622 sparse sparse Sample 26 0.0092 sparse 0.475 sparse 0.582 generally sparse Sample 27 0.0107 generally 0.516 sparse 0.792 sparse sparse Sample 28 0.0128 dense 0.37 generally 0.481 dense dense Sample 29 0.0116 generally 0.352 generally 0.416 dense dense Sample 30 0.0112 generally 0.368 generally 0.538 generally generally
[0057] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details. For example, combining other physical indicators such as color, thickness, etc. to explore the relationship between light transmittance and tobacco leaf looseness also falls within the scope of protection of the present invention.
Claims
1. A method for classifying tobacco leaf density, characterized in that: It includes the following steps: (1) Measure the light transmittance index T of the tobacco leaves, and classify the density of the tobacco leaves according to the magnitude of the light transmittance index T; (2) Measure the physical indexes of the tobacco leaves, and classify the density of the tobacco leaves according to the magnitude of the physical indexes; (3) Conduct a comprehensive analysis based on the light transmittance index T and the physical indexes of the tobacco leaves, and finally determine the classification of the density of the tobacco leaves.
2. The classification method according to claim 1, characterized in that: The classification standard of the density of the tobacco leaves in step (1) according to the magnitude of the light transmittance index T is as follows: when the light transmittance T > 0.58, it is "sparse"; when the light transmittance T < 0.52, it is "dense"; when the light transmittance 0.52 ≤ T ≤ 0.58, it is "general"; the physical indexes of the tobacco leaves in step (2) are the width-to-length ratio and the gram weight ratio, and the classification standard of the density of the tobacco leaves according to the magnitude of the width-to-length ratio and the gram weight ratio is as follows: when the width-to-length ratio > 0.37 or the gram weight ratio < 0.010, it is "sparse"; when the width-to-length ratio < 0.25 or the gram weight ratio > 0.012, it is "dense"; when 0.25 ≤ width-to-length ratio ≤ 0.37 or 0.010 ≤ gram weight ratio ≤ 0.012, it is "general".
3. The classification method according to claim 2, characterized in that: In step (3), a comprehensive analysis is conducted based on the light transmittance index T and the physical indexes of the tobacco leaves, and the classification of the density of the tobacco leaves is finally determined according to the following steps: (31) When T ≥ 0.62, it is directly classified as "sparse"; when T ≤ 0.495, it is directly classified as "dense"; (32) When 0.58 < T < 0.62, the following classification is used as the standard: (321) When one physical index is "sparse" and the other physical index is "general" or "dense", the final classification is "sparse"; (322) When the physical indexes are "general, dense" or "dense, general", the final classification is "general"; (323) When the two physical indexes are "dense, dense", the final classification is "general"; (33) When 0.495 < T < 0.52, the following classification is used as the standard: (331) When one physical index is "dense" and the other physical index is "general" or "sparse", the final classification is "dense"; (332) When the physical indexes are "sparse, general" or "general, sparse", the final classification is "general"; (333) When the two physical indexes are "sparse, sparse", the final classification is "general"; (34) When 0.52 ≤ T ≤ 0.58 and one of the physical indexes is "general", the final classification is "general"; (35) When 0.52 ≤ T ≤ 0.58 and there is no "general" in the physical indexes, the following classification is used as the standard: (351) When the physical indexes are "sparse, sparse", the final classification is "sparse"; (352) When the physical indexes are "dense, dense", the final classification is "dense"; (353) When the physical indexes are "dense, sparse" or "sparse, dense", the final classification is "general".
4. The classification method according to claim 1, characterized in that: Step (1) The steps of measuring the light transmittance index T of the tobacco leaf are as follows: selecting no less than three measuring points on the dry tobacco leaf; using a light intensity meter to measure the light intensity I of each measuring point passing through the tobacco leaf; t，i and initial light intensity I0, calculate the transmittance of each measurement point Then the transmittance index T is obtained by calculating the average transmittance of multiple measurement points.
5. The classification method according to claim 2, characterized in that: The steps for measuring the gram-to-weight ratio and the width-to-length ratio of the tobacco leaves in step (2) are as follows: (21) measuring the maximum width and maximum length of the dried tobacco leaves and calculating the width-to-length ratio; (22) weighing the mass (g) of the dried tobacco leaf sample and measuring its surface area (cm 2 ), calculate the mass to surface area ratio, i.e. gram to weight ratio.
6. The classification method according to claim 4, characterized in that: The light intensity meter includes a white light LED light source and a photosensitive probe, and the power of the light source is not less than 5 watts; the distance between the light source and the surface of the tobacco leaf sample is fixed at 10 cm; the measurement process is carried out in an environment with controlled light.
7. The classification method according to claim 1, characterized in that: When measuring the indexes of the tobacco leaves, it is necessary to ensure that its surface is flat and dry.
8. The classification method according to claim 4, characterized in that: There are three measuring points, which are selected as follows: the first measuring point is the center of the leaf vein and at the center between the leaf vein and the edge of the leaf blade; the second measuring point is the tip of the leaf and at the center between the leaf vein and the edge of the leaf blade; the third measuring point is the petiole end and at the center between the leaf vein and the edge of the leaf blade.