Method for measuring spatial distribution of tobacco shreds based on three-dimensional imaging of x-ray microscope

Abstract

This invention discloses a method for measuring the spatial distribution of tobacco shreds based on three-dimensional imaging using X-ray microscopy. The method involves pre-selecting or labeling different types of mixed tobacco shreds, taking X-ray micrographs of the finished cigarette or the mixed tobacco shreds from different angles, and then overlaying these images to obtain the spatial distribution of the mixed or rolled tobacco shreds. The distribution is then compared with a random distribution model to determine whether the different types of tobacco shreds are evenly mixed. This invention's detection method is non-destructive and can be used to detect the effects on finished cigarette products.

Description

Technical Field

[0001] This invention relates to a method for measuring the spatial distribution of different tobacco shreds based on three-dimensional imaging using X-ray microscopy, belonging to the field of tobacco detection and analysis. Background Technology

[0002] Tobacco uniformity refers to the degree of even distribution achieved through blending different types of tobacco during cigarette processing. A higher degree of uniformity in the distribution of different tobacco types within a blend results in more uniform and stable physical, chemical, and sensory qualities of the product, making it a crucial factor influencing cigarette smoking quality. Currently, most evaluation indicators used by tobacco manufacturers reflect the overall blending uniformity, making it difficult to assess the uniformity of tobacco components within smaller units, such as a single cigarette. Since the blending effect significantly impacts the physicochemical properties and sensory quality of cigarettes, evaluating the uniformity of blended tobacco within smaller units is essential. Summary of the Invention

[0003] To overcome the shortcomings of existing technologies, this invention proposes a method for measuring the spatial distribution of tobacco shreds based on three-dimensional imaging using X-ray microscopy. This method aims to non-destructively inspect finished cigarette products, thereby assessing the uniformity of mixing between different tobacco shreds and improving the accuracy and efficiency of the assessment.

[0004] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0005] The present invention provides a method for measuring the spatial distribution of tobacco shreds based on three-dimensional imaging using X-ray microscopy, characterized by comprising the following steps:

[0006] Step 1: Take the tobacco shreds whose distribution status is to be evaluated, add a labeling element solution with a certain concentration to it, and mix it with other tobacco shreds according to the process flow; and select the mixed tobacco shreds as the test sample, or prepare the mixed tobacco shreds into cigarettes according to the rolling process and use them as the test sample.

[0007] Step 2: Set the X-ray wavelength to the characteristic X-ray absorption wavelength of the marker element, and use X-ray microscopy to take pictures of the test sample layer by layer to obtain several cigarette images with the marker element. After superimposing them, a cigarette superimposed image containing the three-dimensional distribution information of the marker element is obtained. The cigarette superimposed image is then converted into a three-dimensional grayscale image composed of pixels with grayscale values ​​between 0 and 255.

[0008] Step 3: Based on the resolution of the three-dimensional grayscale image, obtain the coordinate range information of the coordinate positions of each pixel in the three-dimensional grayscale image that belong to the coordinate positions of the test sample pixel.

[0009] Step 4: Take the average value between the maximum and minimum gray values ​​in the 3D grayscale image as the noise threshold. When the gray value in the 3D grayscale image is lower than the noise threshold, discard the pixel corresponding to the gray value to obtain a point set S containing only the spatial coordinates of the remaining pixels, and the point set S contains n pixels.

[0010] Step 5: Traverse each pixel in the point set S and calculate the distance between each pixel and its nearest neighbor, and then use Equation (1) to calculate the average distance d;

[0011]

[0012] In equation (1), d i The distance between the i-th pixel and its nearest neighbor pixel;

[0013] Step 6: Calculate the expected distance E of the n pixels in the point set S randomly distributed within the coordinate range information using equation (2). d ;

[0014]

[0015] In equation (2), V is the volume calculated from the coordinate range information;

[0016] Step 7: Calculate d and E d The ratio between the two values ​​is considered to be close to "1", and if the ratio is close to "1", then the distribution of the test sample is considered to be close to a uniform distribution; and the ratio is directly proportional to the dispersion of the tobacco distribution.

[0017] The method for measuring the spatial distribution of tobacco shreds based on three-dimensional imaging using X-ray microscopy described in this invention is characterized in that the labeling element is a uniformly dispersed nanoparticle containing a compound or a composition of elements from the 6th to the 56th elements in the periodic table, and the particle size is less than 1 μm.

[0018] The concentration of the labeled element solution is between 0.005M and 1M.

[0019] The present invention provides an electronic device, comprising a memory and a processor, wherein the memory is used to store a program that supports the processor in executing the method for measuring the spatial distribution of tobacco shreds as described in claim 1, and the processor is configured to execute the program stored in the memory.

[0020] The present invention discloses a computer-readable storage medium on which a computer program is stored, wherein the computer program, when executed by a processor, performs the steps of the method for measuring the spatial distribution of tobacco shreds as described in claim 1.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] The detection method of this invention utilizes specific elements contained in tobacco shreds, or the addition of appropriate labeling compounds (such as potassium citrate, calcium carbonate, and other additives), combined with X-ray microscopy imaging technology, to intuitively, accurately, and non-destructively analyze the spatial distribution uniformity of different tobacco shreds in finished cigarettes or small unit tobacco shred samples. Detailed Implementation

[0023] In this embodiment, a method for measuring the spatial distribution of tobacco shreds based on X-ray microscopy three-dimensional imaging is used to characterize whether different tobacco shreds are uniformly mixed, and includes the following steps:

[0024] Step 1: Take the tobacco shreds whose distribution state is to be evaluated, add a labeling element solution of a certain concentration to them, and mix them with other tobacco shreds according to the process flow; select the mixed tobacco shreds as the test sample, or prepare the mixed tobacco shreds into cigarettes according to the rolling process and use them as the test sample. In this embodiment, the labeling element is a compound containing elements from number 6 to 56 in the periodic table or uniformly dispersed nanoparticles (particle size less than 1 μm) of its composition; the concentration of the labeling element solution is between 0.005 M and 1 M;

[0025] Step 2: Set the X-ray wavelength to the characteristic X-ray absorption wavelength of the marked element, and use X-ray microscopy to take pictures of the test sample layer by layer to obtain several cigarette images with marked elements. After superimposing them, a cigarette superimposed image containing the three-dimensional distribution information of the marked elements is obtained. The cigarette superimposed image is then converted into a three-dimensional grayscale image composed of pixels with grayscale values ​​between 0 and 255.

[0026] Step 3: Based on the resolution of the 3D grayscale image, obtain the coordinate range information of the coordinate positions of each pixel in the 3D grayscale image that belong to the coordinate positions of the test sample pixels.

[0027] Step 4: Take the average value between the maximum and minimum gray values ​​in the 3D grayscale image as the noise threshold. When the gray value in the 3D grayscale image is lower than the noise threshold, discard the corresponding pixel, thus obtaining a point set S containing only the spatial coordinates of the remaining pixels, and the point set S contains n pixels.

[0028] Step 5: Traverse each pixel in the point set S and calculate the distance between each pixel and its nearest neighbor, and then use Equation (1) to calculate the average distance d;

[0029]

[0030] In equation (1), d i The distance between the i-th pixel and its nearest neighbor pixel;

[0031] Step 6: Calculate the expected distance E of the n pixels in the point set S randomly distributed within the coordinate range information using equation (2). d ;

[0032]

[0033] In equation (2), V is the volume calculated from the coordinate range information;

[0034] Step 7: Calculate d and E d The ratio between the two values ​​is considered to be close to "1", indicating that the distribution of the test sample is close to a uniform distribution; and the ratio is directly proportional to the dispersion of the tobacco distribution.

[0035] The present invention will be further described below through specific embodiments.

[0036] Example 1:

[0037] The example uses spread-out mixed cigarette tobacco as an example. Since X-rays are penetrating, the test method is also effective when the tobacco is wrapped in cigarette paper.

[0038] A method for measuring the spatial distribution of different tobacco shreds in cigarettes based on three-dimensional imaging using transmission X-ray microscopy:

[0039] Step 1: Take the tobacco shreds whose distribution status is to be evaluated, select potassium as the labeling element, add a 0.5M potassium citrate solution as the labeling agent, and mix it with other tobacco shreds according to the process flow; and select the mixed tobacco shreds as the test sample, or prepare the mixed tobacco shreds into cigarettes according to the rolling process and use them as the test sample.

[0040] Step 2: Lay the sample to be tested flat on the sample stage. Set the X-ray wavelength to the L3 edge absorption wavelength of the marker element K, and use X-ray microscopy to take pictures of the test sample layer by layer to obtain 43 cigarette images with the marker element. After superimposing, a cigarette superimposed image containing the three-dimensional distribution information of the marker element is obtained. The cigarette superimposed image is then converted into a three-dimensional grayscale image composed of pixels with gray values ​​between 0 and 255. Here, its resolution is 512 pixels × 512 pixels.

[0041] Step 3: Based on the resolution of the 3D grayscale image, obtain the coordinate range information of the coordinate positions of each pixel in the 3D grayscale image that belong to the coordinate positions of the test sample pixels. Since the sample is in a flat state in this embodiment, the coordinate range information of the test sample pixel positions is X: [0, 512], Y: [0, 512], Z: [0, 43]. If it is a finished cigarette stick, it is the cylindrical space where the cigarette stick is located;

[0042] Step 4: Since tobacco naturally contains potassium ions, and the potassium ion content is even higher in tobacco labeled with potassium citrate, the grayscale value of tobacco containing potassium citrate is higher than that of ordinary tobacco. There is a significant difference between the grayscale values ​​of the two. The average of the maximum and minimum grayscale values ​​is taken as the noise value, which is 107 in this case. When the grayscale value in the 3D grayscale image is lower than the noise threshold, the pixel corresponding to the corresponding grayscale value is discarded, thus obtaining a point set S containing only the spatial coordinates of the remaining pixels. Point set S contains 49,592 pixels. Some data are shown in Table 1.

[0043] Table 1. Some elements in point set S

[0044]

[0045]

[0046] Step 5: Traverse each pixel in the point set S and calculate the distance between each pixel and its nearest neighbor, and then use Equation (1) to calculate the average distance d;

[0047]

[0048] In equation (1), d i The distance between the i-th pixel and its nearest neighbor pixel;

[0049] After calculation, the average distance d of the point set S in this embodiment is 1.0022.

[0050] Step 6: Calculate the expected distance E of the 49592 pixels in the point set S randomly distributed within the coordinate range information using equation (2). d ;

[0051]

[0052] In equation (2), V is the volume calculated from the coordinate range information;

[0053] The expected distance of the random distribution of point set S in this embodiment is calculated.

[0054] Step 7: Calculate d and E d The ratio between them Less than 1. This type of tobacco is not evenly distributed, but tends to be concentrated.

[0055] In this embodiment, an electronic device includes a memory and a processor. The memory stores a program that supports the processor in executing the methods described above, and the processor is configured to execute the program stored in the memory.

[0056] In this embodiment, a computer-readable storage medium stores a computer program, which is executed by a processor to perform the steps of the above method.

Claims

1. A method for measuring the spatial distribution of tobacco shreds based on three-dimensional imaging using X-ray microscopy, characterized in that, Includes the following steps: Step 1: Take the tobacco shreds whose distribution status is to be evaluated, add a labeling element solution with a certain concentration to it, and then mix it with other tobacco shreds according to the process flow. The mixed tobacco shreds were selected as test samples, or the mixed tobacco shreds were prepared into cigarettes according to the cigarette rolling process and then used as test samples. Step 2: Set the X-ray wavelength to the characteristic X-ray absorption wavelength of the marker element, and use X-ray microscopy to take pictures of the test sample layer by layer to obtain several cigarette images with the marker element. After superimposing them, a cigarette superimposed image containing the three-dimensional distribution information of the marker element is obtained. The cigarette superimposed image is then converted into a three-dimensional grayscale image composed of pixels with grayscale values ​​between 0 and 255. Step 3: Based on the resolution of the three-dimensional grayscale image, obtain the coordinate range information of the coordinate positions of each pixel in the three-dimensional grayscale image that belong to the coordinate positions of the test sample pixel. Step 4: Take the average value between the maximum and minimum gray values ​​in the 3D grayscale image as the noise threshold. When the gray value in the 3D grayscale image is lower than the noise threshold, discard the pixel corresponding to the gray value to obtain a point set S containing only the spatial coordinates of the remaining pixels, and the point set S contains n pixels. Step 5: Traverse each pixel in the point set S and calculate the distance between each pixel and its nearest neighbor, and then use Equation (1) to calculate the average distance d; (1) In equation (1), The distance between the i-th pixel and its nearest neighbor pixel; Step 6: Calculate the expected distance of the n pixels in the point set S randomly distributed within the coordinate range information using equation (2). ; (2) In equation (2), V is the volume calculated from the coordinate range information; Step 7, calculate d and If the ratio between the two values ​​is close to "1", then the distribution of the test sample is considered to be close to a uniform distribution; and the ratio is directly proportional to the dispersion of the tobacco distribution.

2. The method for measuring the spatial distribution of tobacco shreds based on three-dimensional imaging using X-ray microscopy as described in claim 1, characterized in that: The labeled element is a uniformly dispersed nanoparticle composed of a compound containing one or more elements from the periodic table numbered 6 to 56, and the particle size is less than 1 μm.

3. The method for measuring the spatial distribution of tobacco shreds based on three-dimensional imaging using X-ray microscopy as described in claim 1, characterized in that: The concentration of the labeled element solution is between 0.005 M and 1 M.

4. An electronic device, comprising a memory and a processor, characterized in that, The memory is used to store a program that supports the processor in executing the tobacco spatial distribution measurement method of claim 1, and the processor is configured to execute the program stored in the memory.

5. A computer-readable storage medium storing a computer program thereon, characterized in that, The computer program, when run by the processor, executes the steps of the method for measuring the spatial distribution of tobacco shreds as described in claim 1.

Images