A real-time detection device and method for tobacco processing resistance based on two-dimensional fluidized bed high-speed imaging

Abstract

A real-time detection device and method for tobacco shreds' processing resistance based on two-dimensional fluidized bed high-speed imaging, characterized in that it includes a two-dimensional circulating fluidized bed system, a high-speed imaging system, and an image processing system. The advantages are that it uses a fluidized bed reactor and operates through gas-solid two-phase flow, which makes it easy to realize the discretization of tobacco shreds required for image acquisition and analysis, avoiding the cumbersome operation of single-layer material particles in conventional image detection methods. The operation is simple and fast, and it is easy to realize online detection of the production line. The present invention can realize real-time detection and evaluation of tobacco shreds' processing resistance during fluidized processing, and the device is convenient to form standard processing and crushing conditions by adjusting the fluidized gas velocity and particle velocity, providing an effective means for accurately, efficiently and standardizedly evaluating tobacco shreds' processing resistance.

Description

Technical Field

[0001] The invention belongs to the field of tobacco processing, and in particular relates to a real-time detection device and method for tobacco shreds' processing resistance based on two-dimensional fluidized bed high-speed imaging. Background Art

[0002] During the processing, tobacco shreds are continuously subjected to external forces, which will produce broken shreds. The broken shreds directly affect the quality of cigarettes, including the amount of shredded shreds at the end and the rate of turning. For example, during pneumatic conveying and airflow drying, the tobacco shreds will instantly accelerate to the minimum fluidization speed. The violent movement causes the tobacco shreds to produce different degrees of broken shreds. In China, the whole shred rate of tobacco shreds during processing is mainly used to reflect the processing resistance of tobacco shreds. Therefore, processing resistance is directly related to the stability of cigarette quality. In recent years, with the continuous improvement of production technology, the requirements for tobacco shreds quality have also increased. The processing resistance of tobacco shreds has become one of the indicators to measure the stability of tobacco quality.

[0003] At present, there is still a lack of relevant standards for the processing resistance of cigarettes in China. The processing resistance of tobacco is mainly reflected indirectly by the change in the whole-shred rate after the tobacco passes through the process. The tobacco industry standard YC / T178-2003 provides a vibrating sorting screen with three different apertures, which can separate tobacco into four sizes and calculate the tobacco size interval distribution function by the mass fraction of the screen. Although the screening method can reflect the distribution of tobacco size, the screening size is single and it is impossible to obtain a continuous size distribution. It is not simple and direct enough, and there are still human errors caused by subjective differences.

[0004] Du Jinsong and others invented a method and device for measuring the degree of tobacco breakage (patent name: "A method and device for measuring the degree of tobacco breakage"). This method measures the changes in characteristic dimensions before and after the process based on the screening method, which has certain reference significance, but its analysis process is cumbersome and cannot be used for online detection.

[0005] In recent years, image vision inspection technology has made rapid progress. Due to its convenience and speed, this technology has been applied in various fields. However, its application in tobacco characteristic size detection and processing resistance has not yet been discovered. The application of image inspection technology in tobacco processing resistance detection is the focus of the inventors. Summary of the invention

[0006] The present invention is based on the problems existing in the current methods, and proposes a tobacco processing resistance detection device and method based on two-dimensional fluidized bed high-speed imaging. The present invention can realize real-time detection and evaluation of the processing resistance of tobacco during fluidized processing. The device can easily form standard and consistent processing and crushing conditions by adjusting the fluidizing gas velocity and particle velocity, providing an effective means for accurately, efficiently and standardizedly evaluating the processing resistance of tobacco.

[0007] The objective of the present invention is achieved through the following technical solutions:

[0008] A real-time detection device for tobacco processing resistance based on two-dimensional fluidized bed high-speed imaging, characterized in that it includes a two-dimensional circulating fluidized bed system, a high-speed imaging system, and an image processing system.

[0009] The two-dimensional circulating fluidized bed system is composed of a two-dimensional bed body made of a light-transmitting material, an air distribution plate and a feed hopper installed at the bottom of the bed body, a cyclone separator connected to the fluidizing air outlet of the two-dimensional bed body, a return material stop valve and a return material tee and a discharge bin arranged at the lower end of the cyclone separator, and a primary air inlet and a gas flow meter located at the lower end of the two-dimensional bed body. The other outlet of the return material tee is connected to the return material port of the two-dimensional bed body to form a circulation system. At least three pressure difference detection points are arranged on the two-dimensional bed body along the height direction.

[0010] The high-speed imaging system is composed of an illumination light source, a high-speed camera, a high-speed image acquisition card, and a data acquisition cable. The illumination light source is arranged on both sides of the two-dimensional bed along the length direction, and the high-speed camera is arranged on one side of the return port of the two-dimensional bed;

[0011] The image processing system comprises a computer and an image acquisition and processing program installed on the computer.

[0012] In the present invention, the primary air inlet at the lower end of the two-dimensional bed and the fluidizing air outlet at the upper end are located on the same side; the two-dimensional bed has a height of 500-1500 mm, a width of 200-500 mm, and a thickness of 10-50 mm; and the working air velocity in the two-dimensional bed is 3-5 m / s.

[0013] The position of the air distribution plate is between the primary air inlet and the return port along the height of the two-dimensional bed; the circular pores are evenly distributed on the air distribution plate, the pore diameter is 2-5mm, and the opening rate of the air distribution plate is 5-10%.

[0014] The feed hopper is installed on the outside along the vertical direction of the two-dimensional bed. A stop valve and a feed pipe are arranged in sequence at the lower part of the feed hopper. The interface connecting the feed pipe and the two-dimensional bed is located on the upper part of the air distribution plate, and a feed auxiliary air inlet is arranged on the feed pipe.

[0015] The cyclone separator is opposite to the feed hopper side. The cyclone separator is connected to the upper part of the two-dimensional bed through the fluidizing air outlet. The lower part of the cyclone separator is connected to the return valve. The return valve is a U-shaped return valve. The return valve is connected to the inlet of the return tee. One outlet of the return tee is the return port connected to the two-dimensional bed, and the other outlet of the return tee is connected to the discharge bin.

[0016] At the pressure difference detection point, the bed pressure signal is detected by setting a Pitot tube and a pressure sensor.

[0017] There are two gas flow meters, one of which is connected to the primary air inlet at the bottom of the two-dimensional bed for controlling and adjusting the primary air flow; and the other is connected to the feed pipeline for controlling and adjusting the feed auxiliary air flow.

[0018] The illumination light source of the high-speed imaging system includes two LED linear light sources, which are respectively arranged on both sides of the length direction of the two-dimensional bed, and the length direction of the linear light source is parallel to the height direction of the two-dimensional bed; the high-speed camera is arranged on one side of the two-dimensional bed in the thickness direction, and the vertical distance from the two-dimensional bed is 0.3-2m, and the image acquisition frame rate of the high-speed camera is greater than 500fp.

[0019] The image acquisition and processing program is responsible for completing the image acquisition control function and the image processing function, wherein the image acquisition control function refers to controlling the high-speed image acquisition card to complete the real-time acquisition function of the image of the tobacco fluidization process in the two-dimensional bed; the image processing function includes the correction, filtering and enhancement preprocessing of the acquired image, the grayscale segmentation of the tobacco area in the image, the extraction and calculation of the tobacco length parameters, the statistical analysis of the characteristic length of batch-detected tobacco, and the output of the detection index.

[0020] The method for measuring the processing resistance of tobacco shreds using the above device comprises the following steps:

[0021] (1) Moisture balance of tobacco sample: weigh a certain mass of the sample to be tested and put it into the feed hopper;

[0022] (2) Turn on the illumination source of the high-speed imaging system and set the image acquisition frequency, image resolution, and single acquisition duration of the high-speed camera in the image acquisition and processing program;

[0023] (3) Open the hopper stop valve of the two-dimensional bed, introduce the feed auxiliary air of the set flow rate, allow the tobacco to enter the upper part of the air distribution plate in the two-dimensional bed, and then close the feed auxiliary air and hopper stop valve;

[0024] (4) Introduce primary air and return auxiliary air of set flow rate, adjust the three-way valve, so that the tobacco is output from the return valve to the two-dimensional bed, and keep the discharge stop valve closed, so that the tobacco to be tested is circulated and fluidized in the two-dimensional bed;

[0025] (5) Detect the pressure signal of the pressure difference detection point on the two-dimensional bed. After the bed pressure signal is stable, the high-speed imaging system starts to collect images. The collected images of tobacco in the fluidized bed are stored in the computer in time series;

[0026] (6) After completing the image acquisition according to the set detection time interval and detection number, open the discharge stop valve and adjust the three-way valve so that the tobacco is output to the discharge bin through the return valve, and close the primary air and return auxiliary air;

[0027] (7) The image acquisition and processing program processes the collected tobacco images to obtain the length x of each tobacco in the image. i ;

[0028] (8) For all the tobacco in all the images collected at each detection time point, the image acquisition and processing program statistically analyzes the characteristic length x of the tobacco at that detection time point 0.5 , the calculation formula is as follows:

[0029] F(x)=exp (-ax b ) (1)

[0030] x 0.5 =exp [ln(ln2 / a) / b] (2)

[0031] In the above formula, F(x) is the upper cumulative percentage of tobacco length, and x is the tobacco length. By using the tobacco length x and the upper cumulative percentage of tobacco length F(x), the parameter values ​​a and b of formula (1) can be fitted. Substituting them into formula (2) yields x: 0.5 , a and b are constants;

[0032] (9) Calculate the ratio R of the characteristic length of tobacco at each detection time point to the characteristic length of tobacco at the first detection time point. This ratio can quantitatively characterize the processing resistance of tobacco at that processing time point. The calculation formula is as follows:

[0033] R i = x i 0.5 / x0 0.5 (3)

[0034] In the above formula, x0 0.5 is the characteristic length of tobacco at the first detection time point, x i 0.5 is the characteristic length of tobacco at the i-th detection time point, R i The tobacco processing resistance index at the i-th detection time point;

[0035] (10) The image acquisition and processing program outputs the tobacco processing resistance index and characteristic length value at each detection time point.

[0036] The advantages of the device and method of the present invention are:

[0037] (1) The fluidized bed reactor is used to operate the gas-solid two-phase flow, which makes it easy to discretize the tobacco particles required for image acquisition and analysis, avoiding the cumbersome operation of single-layer material particles in conventional image detection methods. The operation is simple and fast, and it is easy to realize online detection of the production line;

[0038] (2) The circulating fluidized conveying process that the tobacco shreds undergo in the device is consistent with the physical processing process that the tobacco shreds undergo in production lines such as pneumatic conveying equipment and airflow drying equipment in actual production. Therefore, the tobacco shreds’ breakage behaviors are similar, and the test results are close to actual production.

[0039] (3) In the detection device and method, the crushing strength of tobacco in the circulating fluidization process can be flexibly and accurately adjusted by the fluidization speed, thereby reflecting the influence of a wide range of processing conditions on the processing resistance of tobacco in actual production; at the same time, by setting a certain fluidization speed, standard and consistent processing crushing conditions can also be formed, providing an effective means for accurately and standardizedly evaluating the processing resistance of tobacco. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 Schematic diagram of the principle of the tobacco detection system for two-dimensional fluidized bed high-speed imaging.

[0041] Figure 2 Schematic diagram of the location of the two-dimensional fluidized bed and imaging system.

[0042] Figure 1 , 2 In: 1. Feed hopper, 2. Stop valve, 3. Two-dimensional bed, 4. Air distribution plate, 5. Return tee, 6. Cyclone separator, 7. Gas flow meter, 8. Pressure difference detection point, 9. Lighting source, 10. High-speed camera, 11. Image acquisition card, 12. Computer, 13. Discharge bin, 14. Cables. DETAILED DESCRIPTION

[0043] The detection device and method of the present invention are further described below in conjunction with the accompanying drawings:

[0044] like Figure 1 , 2 As shown: A real-time detection device for tobacco processing resistance based on two-dimensional fluidized bed high-speed imaging, characterized in that it includes a two-dimensional circulating fluidized bed system, a high-speed imaging system, and an image processing system.

[0045] The two-dimensional circulating fluidized bed system is composed of a two-dimensional bed body 3 made of a light-transmitting material, an air distribution plate 3 and a feed hopper 1 installed at the lower part of the bed body, a cyclone separator 6 connected to the fluidizing air outlet of the two-dimensional bed body, a return material stop valve 2 and a return material tee 5 and a discharge bin 13 arranged at the lower end of the cyclone separator, and a primary air inlet and a gas flow meter 7 located at the lower end of the two-dimensional bed body. The other outlet of the return material tee is connected to the return material port of the two-dimensional bed body to form a circulation system. At least three pressure difference detection points 8 are arranged on the two-dimensional bed body 3 along the height direction;

[0046] The high-speed imaging system is composed of an illumination light source 9, a high-speed camera (CCD camera) 10, a high-speed image acquisition card 11, and a data acquisition cable 14. The illumination light source is arranged on both sides of the two-dimensional bed along the length direction, and the high-speed camera is arranged on the return side along the vertical direction (thickness) of the two-dimensional bed;

[0047] The image processing system comprises a computer and an image acquisition and processing program installed on the computer.

[0048] In the present invention, the primary air inlet at the lower end of the two-dimensional bed and the fluidizing air outlet at the upper end are located on the same side; the two-dimensional bed has a height of 500-1500 mm, a width of 200-500 mm, and a thickness of 10-50 mm; and the working air velocity in the two-dimensional bed is 3-5 m / s.

[0049] The position of the air distribution plate 4 is between the primary air inlet and the return port along the height of the two-dimensional bed; circular pores are evenly distributed on the air distribution plate, the pore diameter is 2-5mm, and the opening rate of the air distribution plate is 5-10%.

[0050] The feed hopper 1 is installed on the outside along the vertical direction of the two-dimensional bed (thickness). The lower part of the feed hopper 1 is provided with a stop valve 2 and a feed pipe in sequence. The interface connecting the feed pipe and the two-dimensional bed is located on the upper part of the air distribution plate 4, and a feed auxiliary air inlet is provided on the feed pipe.

[0051] The cyclone separator 6 is opposite to the feed hopper side. The cyclone separator is connected to the upper part of the two-dimensional bed through the fluidizing air outlet, and the lower part of the cyclone separator is connected to the return valve. The return valve is a U-shaped return valve. The return valve is connected to the inlet of the return tee 5. One outlet of the return tee 5 is the return port connected to the two-dimensional bed, and the other outlet of the return tee is connected to the discharge bin 13.

[0052] At the pressure difference detection point 8, the bed pressure signal is detected by setting a Pitot tube and a pressure sensor.

[0053] There are two gas flow meters 7, one of which is connected to the primary air inlet at the bottom of the two-dimensional bed for controlling and adjusting the primary air flow; and the other is connected to the feed pipeline for controlling and adjusting the feed auxiliary air flow.

[0054] The illumination light source 9 of the high-speed imaging system includes two LED linear light sources, which are respectively arranged on both sides of the two-dimensional bed 3 along the length direction, and the length direction of the linear light source is parallel to the height direction of the two-dimensional bed; the high-speed camera 10 is arranged on one side of the two-dimensional bed 3 along the thickness direction, and the vertical distance from the two-dimensional bed is 0.3-2m, and the image acquisition frame rate of the high-speed camera is greater than 500fp.

[0055] The image acquisition and processing program is responsible for completing the image acquisition control function and the image processing function, wherein the image acquisition control function refers to controlling the high-speed image acquisition card to complete the real-time acquisition function of the image of the tobacco fluidization process in the two-dimensional bed; the image processing function includes the correction, filtering and enhancement preprocessing of the acquired image, the grayscale segmentation of the tobacco area in the image, the extraction and calculation of the tobacco length parameters, the statistical analysis of the characteristic length of batch-detected tobacco, and the output of the detection index.

[0056] The detection method using the above device is as follows:

[0057] 1) Take samples evenly before and after the processing device, with a sampling volume of 500-800 g. Place the sampled tobacco in a constant temperature and humidity environment for 48 hours to balance the sample moisture to 11%-13%. Weigh 200 g and place it in hopper 1;

[0058] 2) Open the stop valve 2, start the feed auxiliary air, and the tobacco enters the fluidized bed 3 under the action of gravity and wind and is placed on the air distribution plate 4;

[0059] 3) Adjust the three-way valve 5 to keep the discharge stop valve in a normally closed state, so that the tobacco passes through the cyclone separator 6 and the return valve to return to the fluidized bed to form a circulating fluidization;

[0060] 4) Adjust the rotor flowmeter 7 to stabilize the signal of the pressure sensor 8 at the pressure difference detection signal point outside the two-dimensional fluidized bed;

[0061] 5) If Figure 1 As shown: the LED linear light sources 9 placed on both sides of the two-dimensional fluidized bed emit visible light evenly, adjust the brightness of the linear light source, set the CCD camera 10 to capture images at a frame rate greater than 500fps, and set the image resolution to be greater than 2592×1944. Set the primary air flow rate to 100m³ / h;

[0062] 6) The high-speed image acquisition card 11 acquires images in time series, with a single acquisition time of 5 to 8 seconds, and saves the images in time series in the computer 12. After the acquisition is completed, the three-way valve 5 is adjusted to return the tobacco to the discharge bin 13, and the primary air and return auxiliary air are closed;

[0063] 7) The collected images are pre-processed (corrected, filtered, enhanced, etc.) by the image processing system installed in the computer to obtain the characteristic length dimension x of each tobacco strand. i .

[0064] 8) According to formulas (1), (2) and (3), the processing resistance index of the tobacco before and after the processing device is obtained respectively, and the tobacco length distribution and processing resistance index in each time series are output;

[0065] Example 1

[0066] In order to enable those skilled in the art to better understand the tobacco processing resistance detection method and device provided by the present invention, the technical scheme of the present invention is clearly and completely described below in combination with the following examples. Obviously, the described examples are only part of the embodiments of the present invention, rather than all the embodiments of the present invention.

[0067] In the air conveying process, 200g of samples are taken in each time series, and the moisture is balanced to 11%~13% in a constant temperature and humidity environment. The characteristic length x of the tobacco in each time series is measured using the above-mentioned tobacco processing resistance detection device and method. i 0.5 and the characteristic length of tobacco at the first time point x0 0.5 , and the corresponding ratio R i That is, it indicates the processing resistance of tobacco in this air conveying process. Since the movement of tobacco in the fluidized bed is similar to that in the pneumatic conveying state, R is used. i It can more accurately measure the processing resistance of tobacco in this state.

[0068] In summary, this invention establishes a method for detecting the processing resistance of tobacco shreds based on two-dimensional fluidized bed high-speed imaging. i The closer it is to 1, the better the processing resistance of the tobacco is, and the less breakage during processing; similarly, the processing resistance of tobacco R i The smaller the value is than 1, the more broken shreds are produced during the processing of the shredded tobacco, and the worse the processing resistance is. The method uses fluidization to realize online production detection, which is more flexible and convenient to operate and has important significance for monitoring the quality of shredded tobacco.

Claims

1. A real-time detection device for tobacco processing resistance based on two-dimensional fluidized bed high-speed imaging, characterized in that: Including two-dimensional circulating fluidized bed system, high-speed imaging system, image processing system, The two-dimensional circulating fluidized bed system consists of a two-dimensional bed body made of a light-transmitting material, an air distribution plate and a feed hopper installed at the bottom of the bed body, a cyclone separator connected to the fluidizing air outlet of the two-dimensional bed body, a return stop valve and a return tee and a discharge bin arranged at the lower end of the cyclone separator, and a primary air inlet and a gas flow meter located at the lower end of the two-dimensional bed body. The other outlet of the return tee is connected to the return port of the two-dimensional bed body to form a circulation system. At least three pressure difference detection points are arranged on the two-dimensional bed body along the height direction; the feed hopper is installed along the vertical direction of the two-dimensional bed body. On the outside, a stop valve and a feed pipe are sequentially arranged at the lower part of the feed hopper. The interface connecting the feed pipe and the two-dimensional bed is located at the upper part of the air distribution plate, and a feed auxiliary air inlet is arranged on the feed pipe; the cyclone separator is opposite to the side of the feed hopper, and the cyclone separator is connected to the upper part of the two-dimensional bed through the fluidizing air outlet, and the lower part of the cyclone separator is connected to the return valve, which is a U-shaped return valve. The return valve is connected to the inlet of the return tee, and one outlet of the return tee is the return port connected to the two-dimensional bed, and the other outlet of the return tee is connected to the discharge bin; The high-speed imaging system is composed of an illumination light source, a high-speed camera, a high-speed image acquisition card, and a data acquisition cable. The illumination light source is arranged on both sides of the two-dimensional bed along the length direction, and the high-speed camera is arranged on one side of the return port of the two-dimensional bed; The image processing system comprises a computer and an image acquisition and processing program installed on the computer.

2. The real-time detection device for tobacco processing resistance based on two-dimensional fluidized bed high-speed imaging according to claim 1 is characterized in that: The primary air inlet at the lower end of the two-dimensional bed and the fluidizing air outlet at the upper end are located on the same side; the height of the two-dimensional bed is 500-1500 mm, the width is 200-500 mm, and the thickness is 10-50 mm; the working air velocity in the two-dimensional bed is 3-5 m / s.

3. The real-time detection device for tobacco processing resistance based on two-dimensional fluidized bed high-speed imaging according to claim 1 is characterized in that: The position of the air distribution plate is between the primary air inlet and the return port along the height of the two-dimensional bed; the circular pores are evenly distributed on the air distribution plate, the pore diameter is 2-5mm, and the opening rate of the air distribution plate is 5-10%.

4. The real-time detection device for tobacco processing resistance based on two-dimensional fluidized bed high-speed imaging according to claim 1 is characterized in that: At the pressure difference detection point, the bed pressure signal is detected by setting a Pitot tube and a pressure sensor.

5. The real-time detection device for tobacco processing resistance based on two-dimensional fluidized bed high-speed imaging according to claim 1 is characterized in that: There are two gas flow meters, one of which is connected to the primary air inlet at the bottom of the two-dimensional bed for controlling and adjusting the primary air flow; and the other is connected to the feed pipeline for controlling and adjusting the feed auxiliary air flow.

6. The real-time detection device for tobacco processing resistance based on two-dimensional fluidized bed high-speed imaging according to claim 1 is characterized in that: The illumination light source of the high-speed imaging system includes two LED linear light sources, which are respectively arranged on both sides of the length direction of the two-dimensional bed, and the length direction of the linear light source is parallel to the height direction of the two-dimensional bed; the high-speed camera is arranged on one side of the two-dimensional bed in the thickness direction, and the vertical distance from the two-dimensional bed is 0.3-2m, and the image acquisition frame rate of the high-speed camera is greater than 500fp.

7. The real-time detection device for tobacco processing resistance based on two-dimensional fluidized bed high-speed imaging according to claim 1 is characterized in that: The image acquisition and processing program is responsible for completing the image acquisition control function and the image processing function, wherein the image acquisition control function refers to controlling the high-speed image acquisition card to complete the real-time acquisition function of the image of the tobacco fluidization process in the two-dimensional bed; the image processing function includes the correction, filtering and enhancement preprocessing of the acquired image, the grayscale segmentation of the tobacco area in the image, the extraction and calculation of the tobacco length parameters, the statistical analysis of the characteristic length of batch-detected tobacco, and the output of the detection index.

8. A method for measuring the processing resistance of tobacco shreds using the real-time detection device according to claims 1-7, characterized in that: The following steps are involved: (1) Moisture balance of tobacco sample: weigh a certain mass of the sample to be tested and put it into the feed hopper; (2) Turn on the illumination source of the high-speed imaging system and set the image acquisition frequency, image resolution, and single acquisition duration of the high-speed camera in the image acquisition and processing program; (3) Open the hopper stop valve of the two-dimensional bed, introduce the feed auxiliary air of the set flow rate, allow the tobacco to enter the upper part of the air distribution plate in the two-dimensional bed, and then close the feed auxiliary air and hopper stop valve; (4) Introduce primary air and return auxiliary air of set flow rate, adjust the three-way valve, so that the tobacco is output from the return valve to the two-dimensional bed, and keep the discharge stop valve closed, so that the tobacco to be tested is circulated and fluidized in the two-dimensional bed; (5) Detect the pressure signal of the pressure difference detection point on the two-dimensional bed. After the bed pressure signal is stable, the high-speed imaging system starts to collect images. The collected images of tobacco in the fluidized bed are stored in the computer in time series; (6) After completing the image acquisition according to the set detection time interval and detection number, open the discharge stop valve and adjust the three-way valve so that the tobacco is output to the discharge bin through the return valve, and close the primary air and return auxiliary air; (7) The image acquisition and processing program processes the collected tobacco images to obtain the length x of each tobacco in the image. i ; (8) For all the tobacco in all the images collected at each detection time point, the image acquisition and processing program statistically analyzes the characteristic length x of the tobacco at that detection time point 0.5 , the calculation formula is as follows: F(x)=exp (-ax b ) (1) x 0.5 =exp [ln(ln2 / a) / b] (2) In the above formula, F(x) is the upper cumulative percentage of tobacco length, and x is the tobacco length. By using the tobacco length x and the upper cumulative percentage of tobacco length F(x), the parameter values ​​a and b of formula (1) can be fitted. Substituting them into formula (2) yields x: 0.5 , a and b are constants; (9) Calculate the ratio R of the characteristic length of tobacco at each detection time point to the characteristic length of tobacco at the first detection time point. This ratio can quantitatively characterize the processing resistance of tobacco at that processing time point. The calculation formula is as follows: R i = x i 0.5 / x0 0.5 (3) In the above formula, x0 0.5 is the characteristic length of tobacco at the first detection time point, x i 0.5 is the characteristic length of tobacco at the i-th detection time point, R i The tobacco processing resistance index at the i-th detection time point; (10) The image acquisition and processing program outputs the tobacco processing resistance index and characteristic length value at each detection time point.

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