A testing method for the particle size distribution of a mineral fireproof powder

Abstract

The present invention relates to the technical field of testing particle size, and particularly relates to a method for testing the particle size distribution of mineral fireproof powder. According to the morphological characteristics of the particle connected domain within the sliding window, the present invention obtains the dispersion degree of the fireproof powder in the sliding window; in the light spot connected domain of the sliding window, according to the gradient characteristics of the light spot edge pixel points within different pixel neighborhood windows, the present invention obtains the blurring degree of the light spot edge corresponding to the sliding window; according to the brightness distribution of different light spot pixel points within the sliding window, the present invention obtains the evaluation of the brightness and darkness difference of the sliding window; obtains the illumination uniformity degree of the sliding window, combines the initial light scattering intensity corresponding to each sliding window at different angles, obtains the corrected light scattering intensity of each sliding window at each angle, and obtains the overall light scattering intensity of each fireproof powder particle; conducts particle size distribution testing on the fireproof powder particles. By obtaining the accurate light scattering intensity of each fireproof powder particle, the present invention improves the accuracy of the particle size distribution.

Description

Technical Field

[0001] The present invention relates to the technical field of testing particle size, and particularly relates to a method for testing the particle size distribution of a mineral fireproof powder. Background Art

[0002] Particle size distribution is a very important physical property for the application performance of fireproof powder. The particle size directly affects the fluidity, mixability of the material, and the heat conduction performance in a high-temperature environment. Therefore, in order to ensure the improvement of product quality, it is necessary to accurately analyze and control the particle size distribution of the mineral fireproof powder.

[0003] In the prior art, the particle size distribution of the mineral fireproof powder is tested by laser particle size analysis method, which can provide a fine particle size distribution map and identify the subtle particle differences in the sample. However, due to the influence of other light sources, the irradiation of the laser beam is uneven, which affects the detection of scattered light, and further affects the testing of the particle size distribution of the fireproof powder, resulting in poor accuracy of the particle size distribution test. Summary of the Invention

[0004] In order to solve the technical problems that the irradiation of the laser beam is uneven due to the influence of other light sources and the accuracy of the particle size distribution test is poor, the purpose of the present invention is to provide a method for testing the particle size distribution of a mineral fireproof powder, and the specific technical solution adopted is as follows:

[0005] The present invention proposes a method for testing the particle size distribution of a mineral fireproof powder, and the method includes:

[0006] Obtain the particle images of the fireproof powder at different angles and the corresponding initial light scattering intensities;

[0007] For any angle, construct a sliding window to traverse the particle image of the fireproof powder, and obtain the particle connected domain and the light spot connected domain in each sliding window; for any sliding window, obtain the particle exposure degree of the sliding window according to the morphological characteristics of the particle connected domain in the sliding window; according to the distribution of the particle connected domain in the sliding window and the particle exposure degree, obtain the dispersion degree of the fireproof powder in the sliding window.

[0008] In the light spot connected domain of the sliding window, obtain the pixel neighborhood window corresponding to each light spot edge pixel point; according to the gradient characteristics of the light spot edge pixel points in different pixel neighborhood windows, obtain the blurring degree of the light spot edge corresponding to the sliding window; according to the brightness distribution of different light spot pixel points in the sliding window, obtain the bright-dark difference evaluation of the sliding window; according to the dispersion degree of the fireproof powder in the sliding window, the blurring degree of the light spot edge, and the bright-dark difference evaluation, obtain the irradiation uniformity of the sliding window.

[0009] Based on the initial light scattering intensity corresponding to each sliding window at different angles and the illumination uniformity, obtain the corrected light scattering intensity of each sliding window at each angle, and obtain the overall light scattering intensity of each fireproof powder particle;

[0010] Perform particle size distribution testing on the fireproof powder particles according to the overall light scattering intensity.

[0011] Further, the method for obtaining the particle connected domain and the spot connected domain includes:

[0012] Use a connected domain detection algorithm to obtain multiple connected domains of each sliding window;

[0013] Obtain the average brightness value of all pixel points in each connected domain as the local brightness level; obtain the average of the local brightness levels in all connected domains as the overall brightness level; obtain the degree of brightness fluctuation of the pixel points in all connected domains as the brightness fluctuation value; obtain the sum of the preset multiples of the overall brightness level and the brightness fluctuation value as the brightness reference value;

[0014] If the local brightness level of the connected domain is greater than or equal to the brightness reference value, regard the corresponding connected domain as the spot connected domain, and regard the other connected domains except the spot connected domain as the particle connected domain.

[0015] Further, the method for obtaining the degree of particle exposure includes:

[0016] Construct the minimum bounding rectangle of each particle connected domain;

[0017] Obtain the ratio of the number of pixel points in each particle connected domain to the number of pixel points in the minimum bounding rectangle as the first ratio;

[0018] Obtain the cumulative value of the first ratio corresponding to all particle connected domains in each sliding window as the degree of particle exposure.

[0019] Further, the method for obtaining the degree of dispersion of the fireproof powder includes:

[0020] Obtain the ratio of the number of particle connected domains to the number of pixel points in each sliding window as the particle density of each sliding window;

[0021] Obtain the ratio of the degree of particle exposure to the particle density of each sliding window as the degree of dispersion of the fireproof powder in each sliding window.

[0022] Further, the method for obtaining the degree of blurriness of the spot edge includes:

[0023] Obtain the sum of the gradients of all spot edge pixel points in each pixel neighborhood window as the local gradient level;

[0024] According to the fluctuation degree of the local gradient level of different pixel neighborhood windows within the sliding window, the blurring degree of the light spot edge of the sliding window is obtained, and the fluctuation degree of the local gradient level is negatively correlated with the blurring degree of the light spot edge.

[0025] Further, the obtaining method of the light and dark difference evaluation includes:

[0026] Obtain the difference between the maximum brightness value and the minimum brightness value of the light spot pixel points within the sliding window as the light and dark difference evaluation of the sliding window.

[0027] Further, the obtaining method of the illumination uniformity includes:

[0028] Perform a negative correlation mapping on the light and dark difference evaluation of the sliding window as the first uniformity coefficient;

[0029] Fuse the first uniformity coefficient, the blurring degree of the light spot edge, and the dispersion degree of the fire prevention powder of the sliding window as the illumination uniformity of the sliding window.

[0030] Further, the obtaining method of the corrected light scattering intensity includes:

[0031] According to the illumination uniformity corresponding to the sliding window at different angles, screen out the normal illumination window and the abnormal illumination window at each angle;

[0032] For any angle, if the sliding window is an abnormal illumination window, obtain the normal illumination window corresponding to the abnormal illumination window at other angles as the target window; obtain the mean value of the illumination uniformity of all target windows as the first mean value; obtain the mean value of the initial light scattering intensity at the corresponding angles of all target windows as the second mean value; obtain the ratio of the first mean value to the illumination uniformity of the abnormal illumination window at the corresponding angle, and calculate the product between the ratio result and the second mean value as the correction intensity weight;

[0033] Obtain the sum of the initial light scattering intensity and the correction intensity weight at the corresponding angle of each abnormal illumination window as the corrected light scattering intensity of each abnormal illumination window at the corresponding angle;

[0034] If the sliding window is a normal illumination window, use the initial light scattering intensity at the corresponding angle of the sliding window as the corrected light scattering intensity.

[0035] Further, the screening out of the normal illumination window and the abnormal illumination window at each angle includes:

[0036] For any angle, if the illumination uniformity of the sliding window is less than the preset uniformity threshold, regard the corresponding sliding window as an abnormal illumination window; if the illumination uniformity of the sliding window is greater than or equal to the preset uniformity threshold, regard the corresponding sliding window as a normal illumination window.

[0037] Furthermore, the method for obtaining the overall light scattering intensity includes:

[0038] Obtaining the ratio of the corrected light scattering intensity to the initial light scattering intensity of each sliding window at each angle as the intensity ratio;

[0039] Calculating the product of the initial light scattering intensity and the intensity ratio of the sliding window corresponding to each angle of each fireproof powder particle as the local light scattering intensity of the sliding window corresponding to each angle of each fireproof powder particle;

[0040] Taking the average value of the corrected light scattering intensities of the sliding windows corresponding to the same fireproof powder particle at different angles as the overall light scattering intensity of each fireproof powder particle.

[0041] The present invention has the following beneficial effects:

[0042] For any angle, the present invention constructs a sliding window to traverse the image of fireproof powder particles, obtains the particle connected domain and the light spot connected domain within each sliding window. By means of the sliding window, the entire image can be systematically and completely traversed to ensure that the information of each fireproof powder particle and the light spot around it is captured; for any sliding window, the morphological characteristics and distribution of the particle connected domain within the sliding window are analyzed to obtain the dispersion degree of the fireproof powder in the sliding window; in the light spot connected domain of the sliding window, the pixel neighborhood window corresponding to each light spot edge pixel point can be obtained to more accurately capture the fine features of the light spot edge; considering that the light spot shows a more gentle transition and the light spot edge is more blurred, according to the gradient characteristics of the light spot edge pixel points within different pixel neighborhood windows, the blurring degree of the light spot edge corresponding to the sliding window is obtained. By analyzing the gradient characteristics, the change of the brightness or color intensity of the light spot edge pixel points is reflected, and the blurring degree of the light spot edge is quantified; according to the brightness distribution of different light spot pixel points within the sliding window, the bright-dark difference evaluation of the sliding window is obtained, which reflects the brightness distribution uniformity of the light spot in the sliding window; according to the dispersion degree of the fireproof powder, the blurring degree of the light spot edge and the bright-dark difference evaluation of the sliding window, the irradiation uniformity degree of the sliding window is obtained, avoiding the one-sidedness that may be brought by a single index and improving the accuracy and reliability of the evaluation; according to the initial light scattering intensity corresponding to each sliding window at different angles and the irradiation uniformity degree, the corrected light scattering intensity of each sliding window at each angle is obtained, and the overall light scattering intensity of each fireproof powder particle is obtained, taking into account the influence of the irradiation uniformity degree and more accurately reflecting the light scattering characteristics of the particles; performing particle size distribution testing on the fireproof powder particles. The present invention improves the accuracy of the particle size distribution by obtaining the accurate initial light scattering intensity of each fireproof powder particle. The present invention obtains the accurate light scattering intensity of each fireproof powder particle by considering the influence of uneven laser beam irradiation, thereby improving the accuracy of the particle size distribution. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0044] Figure 1 It is a flowchart of a method for testing the particle size distribution of a mineral fireproof powder provided by an embodiment of the present invention;

[0045] Figure 2 It is a flowchart of a method for obtaining a particle connection domain and a light spot connection domain provided by an embodiment of the present invention;

[0046] Figure 3 It is a flowchart of a method for obtaining a corrected light scattering intensity provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0047] In order to further elaborate on the technical means and effects adopted by the present invention to achieve the intended invention purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details a method for testing the particle size distribution of a mineral fireproof powder proposed according to the present invention, including its specific implementation manner, structure, characteristics and effects. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs.

[0049] The following specifically describes the specific solution of a method for testing the particle size distribution of a mineral fireproof powder provided by the present invention in conjunction with the accompanying drawings.

[0050] Please refer to Figure 1 , which shows a flowchart of a method for testing the particle size distribution of a mineral fireproof powder provided by an embodiment of the present invention. The specific method includes:

[0051] Step S1: Obtain the images of the fireproof powder particles at different angles and the corresponding initial light scattering intensities.

[0052] In an embodiment of the present invention, considering that the irradiation of the laser beam is uneven, resulting in poor accuracy of particle size distribution testing, it is necessary to analyze the irradiation conditions at different angles and correct the initial light scattering intensity. First, a dispersant or dispersion liquid is added to the fireproof powder sample to disperse the sample into individual particles. The dispersed fireproof powder particles are injected into the measuring cell of the laser particle size analyzer. The laser particle size analyzer receives the light scattered back from the fireproof powder particles at multiple angles, takes images of the fireproof powder particles under the irradiation of the laser beam at multiple angles, and configures a photodetector to record the initial light scattering intensity at different angles. Therefore, the images of the fireproof powder particles at different angles and the corresponding initial light scattering intensities are obtained. Among them, the initial light scattering intensity at each angle reflects the initial light scattering intensity of the fireproof powder particles in the corresponding fireproof powder particle image.

[0053] Step S2: For any angle, construct a sliding window to traverse the fireproof powder particle image, and obtain the particle connected domain and the light spot connected domain within each sliding window; for any sliding window, obtain the particle exposure degree of the sliding window according to the morphological characteristics of the particle connected domain within the sliding window; according to the distribution of the particle connected domain within the sliding window and the particle exposure degree, obtain the dispersion degree of the fireproof powder in the sliding window.

[0054] In order to efficiently process a large amount of image data, more specifically analyze the local features of the image, and more accurately understand and analyze the image content; for any angle, construct a sliding window to traverse the fireproof powder particle image; it should be noted that in an embodiment of the present invention, the sliding window starts traversing from the upper left corner of the image, and the size is 30×30; in other embodiments of the present invention, the size of the sliding window can be specifically set according to the specific situation, and no limitation and elaboration will be made here.

[0055] When the laser beam irradiates the fireproof powder particles, due to different aggregation conditions between the particles, an uneven irradiation effect affects the formation and distribution of the light spots on the particle surface. Therefore, the particle connected domain and the light spot connected domain within each sliding window are obtained for analysis.

[0056] Preferably, in an embodiment of the present invention, for the method of obtaining the particle connected domain and the light spot connected domain, please refer to Figure 2 , which shows a flowchart of a method for obtaining the particle connected domain and the light spot connected domain, including:

[0057] Step S201: Use a connected component detection algorithm to obtain multiple connected components of each sliding window.

[0058] The connected component detection algorithm can reduce the interference of noise to the analysis and help subsequent separate processing and analysis of each region. It should be noted that the specific connected component detection algorithm is a well-known technical means for those skilled in the art, and no elaboration will be made here.

[0059] Step S202: Obtain the average brightness value of all pixel points within each connected component as the local brightness level; obtain the average of the local brightness levels within all connected components as the overall brightness level; obtain the degree of brightness fluctuation of the pixel points within all connected components as the brightness fluctuation value; obtain the sum of the preset multiple of the overall brightness level and the brightness fluctuation value as the brightness reference value.

[0060] Considering the characteristics that the brightness of the light spot is relatively large and the brightness of the particle itself is relatively small, analyze the brightness values of the pixel points within the connected component, combine the overall brightness level and the brightness fluctuation value, ensure that the reference value takes into account both the average brightness and the range of brightness variation, which helps to more accurately identify the light spot and the particle.

[0061] It should be noted that in an embodiment of the present invention, the degree of fluctuation can be represented by calculating the standard deviation. The larger the standard deviation, the greater the degree of fluctuation; the smaller the standard deviation, the smaller the degree of fluctuation. In other embodiments of the present invention, the degree of fluctuation can also be represented by calculating the variance or the range. The specific means are well-known technical means to those skilled in the art and will not be elaborated here.

[0062] It should be noted that in an embodiment of the present invention, the preset multiple is 2 in order to reflect the discreteness and stability of the brightness distribution. In other embodiments of the present invention, the preset multiple can be specifically set according to the specific situation and will not be elaborated here.

[0063] Step S203: If the local brightness level of the connected component is greater than or equal to the brightness reference value, regard the corresponding connected component as the light spot connected component, and regard the other connected components except the light spot connected component as the particle connected component.

[0064] The larger the local brightness level, the larger the brightness value of each pixel point within the connected component, and the more it corresponds to the light spot connected component.

[0065] The morphological characteristics of the particle connected component reflect the degree of exposure and distribution of the particles. The larger the morphological characteristics, the more characteristics of the particles in the area where they are located, and the greater the degree of exposure. According to the morphological characteristics of the particle connected component within each sliding window, obtain the degree of particle exposure of each sliding window.

[0066] Preferably, in an embodiment of the present invention, the method for obtaining the degree of particle exposure includes:

[0067] Construct the minimum bounding rectangle of each particle connected component; obtain the ratio between the number of pixel points within each particle connected component and the number of pixel points within the minimum bounding rectangle as the first ratio;

[0068] Obtain the cumulative value of the first ratio corresponding to all particle connected components within each sliding window as the degree of particle exposure.

[0069] In an embodiment of the present invention, the formula for the degree of particle exposure is expressed as:

[0070] ;

[0071] wherein, represents the degree of particle exposure of the th sliding window; represents the number of pixel points in the th particle connected domain within the th sliding window; represents the number of pixel points within the maximum circumscribed rectangle corresponding to the th particle connected domain within the th sliding window; represents the number of particle connected domains within the th sliding window.

[0072] In the formula for the degree of particle exposure, the more pixel points there are in the particle connected domain, the more particle characteristics are represented in the area range corresponding to the particle connected domain, and the more the particles are exposed.

[0073] The distribution of particle connected domains and the degree of particle exposure reflect the dispersion of fireproof powder particles in space. The more particle connected domains are distributed, the worse the dispersion of fireproof powder particles in space; the greater the degree of particle exposure, that is, the greater the morphological characteristics of each particle connected domain, the more dispersed the fireproof powder particles are in space, and the smaller the overlapping area between particles. According to the distribution of particle connected domains within the sliding window and the degree of particle exposure, the dispersion degree of fireproof powder in the sliding window is obtained.

[0074] Preferably, in an embodiment of the present invention, the method for obtaining the dispersion degree of fireproof powder includes:

[0075] Obtaining the ratio of the number of particle connected domains to the number of pixel points within each sliding window as the particle density of each sliding window;

[0076] Obtaining the ratio of the degree of particle exposure to the particle density of each sliding window as the dispersion degree of fireproof powder of each sliding window.

[0077] In an embodiment of the present invention, the formula for the dispersion degree of fireproof powder is expressed as:

[0078] ;

[0079] ;

[0080] wherein, represents the dispersion degree of fireproof powder of the th sliding window; represents the Degree of particle exposure of a sliding window; Denote the Degree of particle density of the Denote the Number of fireproof powder particles in the Denote the Number of pixel points in the

[0081] In the formula for the dispersion degree of fireproof powder, the more fireproof powder particles in the sliding window, the greater the degree of particle density, and the less dispersed the particles in the window; the greater the degree of particle exposure, the greater the dispersion degree.

[0082] Step S3: In the light spot connected domain of the sliding window, obtain the pixel neighborhood window corresponding to each light spot edge pixel point; according to the gradient characteristics of the light spot edge pixel points in different pixel neighborhood windows, obtain the blurring degree of the light spot edge corresponding to the sliding window; according to the brightness distribution of different light spot pixel points in the sliding window, obtain the evaluation of the light and dark difference of the sliding window; according to the dispersion degree of fireproof powder, the blurring degree of the light spot edge, and the evaluation of the light and dark difference of the sliding window, obtain the illumination uniformity of the sliding window.

[0083] To avoid being affected by other interference noises and analyze the image details, in the light spot connected domain of the sliding window, obtain the pixel neighborhood window corresponding to each light spot edge pixel point. It should be noted that in an embodiment of the present invention, in the light spot connected domain of the sliding window, traverse from the upper left corner, and use the range of 3×3 centered on each light spot edge pixel point and other pixel points as the pixel neighborhood window. Among them, a pixel point only corresponds to one pixel neighborhood window, and the pixel neighborhood windows do not overlap with each other; in other embodiments of the present invention, the size of the pixel neighborhood window can be specifically set according to specific situations, and no limitation and elaboration are made here.

[0084] The dispersion degrees of fireproof powder in different windows are different, resulting in different manifestations of light spots. By analyzing the gradient characteristics of light spot edge pixel points, the brightness change situation of pixel points in the image is reflected, and the clarity of the edge is more intuitively evaluated. The larger the gradient value of the pixel point, the clearer the edge, with a stronger contrast, and the smaller the blurring degree of the light spot edge. On the contrary, the smaller the gradient value of the pixel point, the softer the edge, and the greater the blurring degree of the light spot edge; according to the gradient characteristics of light spot edge pixel points in different pixel neighborhood windows, obtain the blurring degree of the light spot edge corresponding to the sliding window.

[0085] Preferably, in an embodiment of the present invention, the method for obtaining the blurring degree of the light spot edge includes:

[0086] Obtain the sum of the gradients of all light spot edge pixel points in each pixel neighborhood window as the local gradient level;

[0087] According to the fluctuation degree of the local gradient level of different pixel neighborhood windows within the sliding window, the blurring degree of the spot edge of the sliding window is obtained, and the fluctuation degree of the local gradient level is negatively correlated with the blurring degree of the spot edge.

[0088] It should be noted that in an embodiment of the present invention, the fluctuation degree is represented by calculating the variance. The larger the variance, the greater the fluctuation degree, and the smaller the variance, the smaller the fluctuation degree. In other embodiments of the present invention, the fluctuation degree can also be represented by calculating the standard deviation and the range. The specific means are well-known technical means to those skilled in the art and will not be elaborated here.

[0089] Among them, the greater the fluctuation degree, the more inconsistent the local gradient levels of the pixel neighborhood windows, showing a stronger contrast, and the smaller the blurring degree of the spot edge, presenting a negative correlation.

[0090] In an embodiment of the present invention, the formula for the blurring degree of the spot edge is expressed as:

[0091] ;

[0092] Among them, represents the blurring degree of the spot edge of the th sliding window; represents the number of pixel neighborhood windows within the th sliding window; represents the sum of the gradients of all spot edge pixels within the th pixel neighborhood window within the th sliding window, that is, the local gradient level; represents the mean value of the corresponding local gradient levels of all pixel neighborhood windows within the th sliding window.

[0093] In the formula for the blurring degree of the spot edge, represents calculating the variance of the local gradient levels of different pixel neighborhood windows, representing the fluctuation degree. The larger the variance, the more inconsistent the local gradient levels, the greater the fluctuation degree, the greater the contrast between neighborhood windows, and the smaller the blurring degree of the spot edge; Adding 0.01 at the denominator is to avoid the denominator being 0 and the formula being meaningless.

[0094] By analyzing the brightness distribution of different light spot pixel points within the sliding window, the dispersion of the fireproof powder can be reflected. The more uniform the overall brightness distribution, the smaller the difference between the center and the edge of the light spot, the more uniform the distribution of the fireproof powder, and the smaller the evaluation of the light and dark difference; the more uneven the overall brightness distribution, the greater the difference between the center and the edge of the light spot, the more uneven the distribution of the fireproof powder, and the greater the evaluation of the light and dark difference; according to the brightness distribution of different light spot pixel points within the sliding window, the evaluation of the light and dark difference of the sliding window is obtained.

[0095] Preferably, in an embodiment of the present invention, the method for obtaining the evaluation of the light and dark difference includes:

[0096] Obtain the difference between the maximum brightness value and the minimum brightness value of the light spot pixel points within the sliding window, and use it as the evaluation of the light and dark difference of the sliding window.

[0097] Through the evaluation and analysis of the dispersion degree of the fireproof powder, the blurring degree of the light spot edge, and the light and dark difference, the irradiation uniformity of the sliding window can be evaluated more comprehensively and effectively; the better the dispersion degree of the fireproof powder, the more uniform the distribution of the light spot on the sliding window, making the irradiation uniformity greater; the lower the blurring degree of the light spot edge, the more uniform the light distribution, and the higher the irradiation uniformity; the smaller the light and dark difference, indicating that the light brightness distribution is more uniform, and the light transmission performance of the window is also better, thus the irradiation uniformity is higher; according to the dispersion degree of the fireproof powder, the blurring degree of the light spot edge, and the evaluation of the light and dark difference of the sliding window, the irradiation uniformity of the sliding window is obtained.

[0098] Preferably, in an embodiment of the present invention, the method for obtaining the irradiation uniformity includes:

[0099] Perform a negative correlation mapping on the evaluation of the light and dark difference of the sliding window as the first uniformity coefficient;

[0100] Fuse the first uniformity coefficient of the sliding window, the blurring degree of the light spot edge, and the dispersion degree of the fireproof powder as the irradiation uniformity of the sliding window.

[0101] It should be noted that in some embodiments of the present invention, the fusion can be performed by addition or multiplication methods, and the specific means are well-known technical means to those skilled in the art and will not be elaborated here.

[0102] In an embodiment of the present invention, the formula for the irradiation uniformity is expressed as:

[0103] ;

[0104] Wherein, represents the irradiation uniformity of the th sliding window; represents the dispersion degree of the fireproof powder of the th sliding window; represents the degree of blurring of the light spot edge of the th sliding window; represents the evaluation of the brightness difference of the th sliding window.

[0105] In the formula for the illumination uniformity, adding 0.01 is to avoid a denominator of 0 and make the formula meaningless; that is, a negative correlation mapping is performed on the evaluation of the brightness difference of the th sliding window to obtain the first uniformity coefficient. The larger the first uniformity coefficient, the greater the evaluation of the brightness difference, the greater the contrast difference, the more uneven the brightness presented by the light spot, and the smaller the illumination uniformity; the greater the degree of dispersion of the fireproof powder in the th sliding window, the greater the degree of blurring of the light spot edge, the relatively uniform brightness distribution presented by the light spot, and the greater the illumination uniformity.

[0106] It should be noted that in other embodiments of the present invention, a function can also be used to perform a negative correlation mapping on to construct a correlation relationship where the greater the evaluation of the brightness difference, the smaller the illumination uniformity. The specific means are well-known technical means to those skilled in the art and will not be elaborated here.

[0107] Step S4: According to the initial light scattering intensity corresponding to each sliding window at different angles and the illumination uniformity, obtain the corrected light scattering intensity of each sliding window at each angle, and obtain the overall light scattering intensity of each fireproof powder particle.

[0108] The initial light scattering intensity is the intensity of the scattered light after the interaction between light and matter, reflecting the light scattering ability of the fireproof powder particles. The illumination uniformity is an important factor affecting the accuracy of light scattering measurement. If the illumination is uneven, even the same fireproof powder particles may produce different light scattering intensities at different positions. By considering the illumination uniformity, the initial light scattering intensity can be corrected as necessary, so as to more accurately reflect the true scattering characteristics of the substance at different angles. According to the initial light scattering intensity corresponding to each sliding window at different angles and the illumination uniformity, obtain the corrected light scattering intensity of each sliding window at each angle.

[0109] Preferably, in an embodiment of the present invention, for the method of obtaining the corrected light scattering intensity, please refer to Figure 3 , which shows a flowchart of a method for obtaining the corrected light scattering intensity, including:

[0110] Step S301: According to the illumination uniformity corresponding to the sliding window at different angles, screen out the normal illumination window and the abnormal illumination window at each angle. ​

[0111] The irradiation uniformity of the sliding window reflects the uniformity of the laser beam distribution within the sliding window. The greater the irradiation uniformity, the greater the uniformity of the laser beam distribution; the smaller the irradiation uniformity, the smaller the uniformity of the laser beam distribution. The normal irradiation windows and abnormal irradiation windows at each angle are screened out.

[0112] Preferably, in an embodiment of the present invention, screening out the normal irradiation windows and abnormal irradiation windows at each angle includes:

[0113] For any angle, if the irradiation uniformity of the sliding window is less than the preset uniformity threshold, the corresponding sliding window is taken as an abnormal irradiation window; if the irradiation uniformity of the sliding window is greater than or equal to the preset uniformity threshold, the corresponding sliding window is taken as a normal irradiation window.

[0114] It should be noted that, in an embodiment of the present invention, the size of the preset uniformity threshold is 0.5; in other embodiments of the present invention, the size of the preset uniformity threshold can be specifically set according to specific circumstances, and no limitation and elaboration are made here.

[0115] Step S302: For any angle, if the sliding window is an abnormal irradiation window, obtain the normal irradiation window corresponding to the abnormal irradiation window at other angles as the target window; obtain the mean value of the irradiation uniformity of all target windows as the first mean value; obtain the mean value of the initial light scattering intensity at the corresponding angles of all target windows as the second mean value; obtain the ratio of the first mean value to the irradiation uniformity of the abnormal irradiation window at the corresponding angle, and calculate the product between the ratio result and the second mean value as the correction intensity weight.

[0116] Since the abnormal irradiation window may be caused by special conditions at a specific angle, by selecting the normal irradiation window corresponding to other angles, the initial light scattering intensity of the abnormal irradiation window at the corresponding angle is corrected;

[0117] The first mean value is used to evaluate the general irradiation uniformity of the normal irradiation window and measure the light scattering quality without the influence of abnormal conditions; by calculating the ratio of the first mean value to the irradiation uniformity of the abnormal irradiation window at the corresponding angle, the difference between the abnormal irradiation window and the normal state can be reflected. The greater the difference, the greater the irradiation uniformity of the abnormal irradiation window, that is, the greater the ratio, the greater the degree of correction required; the smaller the difference, the greater the irradiation uniformity of the abnormal irradiation window, the closer it is to the normal state, that is, the smaller the ratio, the smaller the degree of correction required; the second mean value is used to evaluate the general light scattering intensity of the normal irradiation window. The greater the light scattering intensity of the normal irradiation window, the greater the tendency to be corrected.

[0118] Step S303: Obtain the sum of the initial light scattering intensity and the correction intensity weight at the corresponding angle of each abnormal irradiation window, and use it as the corrected light scattering intensity of each abnormal irradiation window at the corresponding angle.

[0119] In an embodiment of the present invention, for an abnormal irradiation window, the formula for the corrected light scattering intensity is expressed as:

[0120] ;

[0121] Wherein, represents the corrected light scattering intensity of the th abnormal irradiation window at the th angle; represents the mean value of the initial light scattering intensity at the angle corresponding to the target window of the th abnormal irradiation window, that is, the second mean value; represents the mean value of the irradiation uniformity of the th abnormal irradiation window corresponding to the target window, that is, the first mean value; represents the irradiation uniformity of the th angle and the th abnormal irradiation window.

[0122] In the formula for the corrected light scattering intensity, the fireproof powder is poorly dispersed within the abnormal irradiation window. Due to the influence of dense particle aggregation, the laser beam cannot be fully received, and the light scattering intensity is relatively small compared to the uniform distribution, with a large deviation. represents the ratio of calculating the first mean value and the irradiation uniformity of the th angle and the th abnormal irradiation window. The larger the ratio, the larger the first mean value, that is, the greater the irradiation uniformity corresponding to the target window. represents the product of calculating the ratio and the second mean value, that is, the correction intensity weight. The larger the correction intensity weight, the larger the second mean value, the greater the irradiation uniformity corresponding to the target window, the greater the initial light scattering intensity, and the greater the need to correct the initial light scattering intensity of the abnormal irradiation window; the greater the initial light scattering intensity of the abnormal irradiation window, the greater the corrected light scattering intensity.

[0123] Step S304: If the sliding window is a normal irradiation window, use the initial light scattering intensity corresponding to the angle of the sliding window as the corrected light scattering intensity.

[0124] Since a fireproof powder particle may appear in images at multiple angles, the corrected light scattering intensities of the sliding window corresponding to different angles are integrated into a comprehensive index, which is convenient for subsequent overall evaluation of the properties of the fireproof powder particles, reflects the overall light scattering ability of the particles, and is an important index for evaluating the particle properties. Obtain the overall light scattering intensity of each fireproof powder particle.

[0125] Preferably, in an embodiment of the present invention, the method for obtaining the overall light scattering intensity includes:

[0126] Obtaining the ratio of the corrected light scattering intensity to the initial light scattering intensity of each sliding window at each angle as the intensity ratio;

[0127] Calculating the product of the initial light scattering intensity and the intensity ratio of the sliding window corresponding to each fireproof powder particle at each angle as the local light scattering intensity of the sliding window corresponding to each fireproof powder particle at each angle;

[0128] Taking the average value of the corrected light scattering intensities of the sliding windows of the same fireproof powder particle at different angles as the overall light scattering intensity of each fireproof powder particle.

[0129] In an embodiment of the present invention, the formula for the overall light scattering intensity is expressed as:

[0130] ;

[0131] Wherein, represents the overall light scattering intensity of the fireproof powder particle ; represents the initial light scattering intensity of the sliding window corresponding to the fireproof powder particle corresponding to the th angle; ; represents the corrected light scattering intensity of the sliding window corresponding to the fireproof powder particle corresponding to the th angle; ; represents the number of angles corresponding to the fireproof powder particle .

[0132] In the formula for the overall light scattering intensity, represents calculating the ratio of the corrected light scattering intensity to the initial light scattering intensity of each sliding window at each angle as the intensity ratio. The greater the corrected light scattering intensity, the greater the degree of correction. The greater the intensity ratio, the greater the correction of the light scattering intensity of the fireproof powder particle.

[0133] Step S5: Conduct a particle size distribution test on the mineral fireproof powder particles according to the overall light scattering intensity.

[0134] By obtaining the overall light scattering intensity of each fireproof powder particle, the scattering characteristics of the particles can be more accurately reflected, which is beneficial to accurately testing the particle size distribution of the fireproof powder particles by the subsequent laser particle size analysis method and more accurately evaluating the performance of the fireproof powder. Conduct a particle size distribution test on the mineral fireproof powder particles according to the overall light scattering intensity. The specific laser particle size analysis method is a well-known technical means for those skilled in the art and will not be elaborated here.

[0135] In summary, according to the morphological characteristics of the particle connection domain within the sliding window, the present invention obtains the dispersion degree of the fire prevention powder in the sliding window; in the light spot connection domain of the sliding window, the pixel neighborhood window corresponding to each light spot edge pixel point is obtained; according to the gradient characteristics of the light spot edge pixel points within different pixel neighborhood windows, the blurring degree of the light spot edge of the corresponding sliding window is obtained; according to the brightness distribution of different light spot pixel points within the sliding window, the bright-dark difference evaluation of the sliding window is obtained; the illumination uniformity degree of the sliding window is obtained, and in combination with the initial light scattering intensity corresponding to each sliding window at different angles, the corrected light scattering intensity of each sliding window at each angle is obtained, and the overall light scattering intensity of each fire prevention powder particle is obtained; the particle size distribution test of the fire prevention powder particles is carried out. By accurately obtaining the light scattering intensity of each fire prevention powder particle, the present invention improves the accuracy of the particle size distribution.

[0136] It should be noted that the above sequence of the embodiments of the present invention is only for description and does not represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0137] Each embodiment in this specification is described in a progressive manner. The same or similar parts among the embodiments can be referred to each other, and the differences between each embodiment and other embodiments are emphasized.

Claims

1. A method for testing particle size distribution of mineral fire retardant powder, characterized in that: The method comprises: Obtaining images of fire retardant powder particles at different angles and the corresponding initial light scattering intensity; For any angle, a sliding window is constructed to traverse the image of the fire retardant powder particles, and the particle connected domain and the light spot connected domain in each sliding window are obtained; for any sliding window, the particle exposure degree of the sliding window is obtained according to the morphological characteristics of the particle connected domain in the sliding window; the fire retardant powder dispersion degree of the sliding window is obtained according to the distribution of the particle connected domain in the sliding window and the particle exposure degree; In the light spot connected domain of the sliding window, the pixel neighborhood window corresponding to each light spot edge pixel point is obtained; the blur degree of the light spot edge of the corresponding sliding window is obtained according to the gradient characteristics of the light spot edge pixel points in different pixel neighborhood windows; the brightness difference evaluation of the sliding window is obtained according to the brightness distribution of different light spot pixel points in the sliding window; the illumination uniformity of the sliding window is obtained according to the dispersion degree of fire retardant powder, blur degree of light spot edge and brightness difference evaluation of the sliding window; According to the initial light scattering intensity corresponding to each sliding window at different angles and the irradiation uniformity, the corrected light scattering intensity of each sliding window at each angle is obtained, and the overall light scattering intensity of each fire retardant powder particle is obtained; The particle size distribution of the fire retardant powder particles is tested according to the overall light scattering intensity.

2. A method for testing particle size distribution of mineral fire retardant powder according to claim 1, characterized in that: The method for acquiring the particle connected domain and the light spot connected domain comprises: A connected domain detection algorithm is used to obtain multiple connected domains of each sliding window; Obtain the average brightness value of all pixels in each connected domain as the local brightness level; obtain the average local brightness level in all connected domains as the overall brightness level; obtain the brightness fluctuation degree of the pixels in all connected domains as the brightness fluctuation value; obtain the sum of the overall brightness level and the preset multiple of the brightness fluctuation value as the brightness reference value; If the local brightness level of the connected domain is greater than or equal to the brightness reference value, the corresponding connected domain is regarded as the light spot connected domain, and the other connected domains except the light spot connected domain are regarded as particle connected domains.

3. A method for testing particle size distribution of mineral fire retardant powder according to claim 1, characterized in that: The method for obtaining the particle exposure degree includes: Construct the maximum enclosing rectangle of each particle connected domain; Obtaining a ratio of the number of pixels in each particle connected domain to the number of pixels in the maximum circumscribed rectangle as a first ratio; The accumulated value of the first ratio corresponding to all particle connected domains in each sliding window is obtained as the particle exposure degree.

4. A method for testing particle size distribution of mineral fire retardant powder according to claim 1, characterized in that: The method for obtaining the dispersion degree of the fire retardant powder comprises: Obtain the ratio of the number of connected domains of particles to the number of pixels in each sliding window as the particle density of each sliding window; The ratio of the particle exposure degree to the particle density degree of each sliding window is obtained as the dispersion degree of the fire retardant powder in each sliding window.

5. A method for testing particle size distribution of mineral fire retardant powder according to claim 1, characterized in that: The method for obtaining the blur degree of the light spot edge includes: Obtain the sum of the gradients of all the pixels at the edge of the light spot in each pixel neighborhood window as the local gradient level; The blur degree of the light spot edge of the sliding window is obtained according to the fluctuation degree of the local gradient level of different pixel neighborhood windows in the sliding window. The fluctuation degree of the local gradient level is negatively correlated with the blur degree of the light spot edge.

6. A method for testing particle size distribution of mineral fire retardant powder according to claim 1, characterized in that: The method for obtaining the brightness-darkness difference evaluation comprises: The difference between the maximum brightness and the minimum brightness of the light spot pixel in the sliding window is obtained as the brightness difference evaluation of the sliding window.

7. A method for testing particle size distribution of mineral fire retardant powder according to claim 1, characterized in that: The method for obtaining the irradiation uniformity comprises: A negative correlation mapping is performed on the brightness and darkness difference evaluation of the sliding window as the first uniformity coefficient; The first uniformity coefficient of the sliding window, the blurring degree of the light spot edge and the dispersion degree of the fire retardant powder are integrated to serve as the illumination uniformity of the sliding window.

8. A method for testing particle size distribution of mineral fire retardant powder according to claim 1, characterized in that: The method for obtaining the corrected light scattering intensity comprises: According to the illumination uniformity of the sliding window at different angles, the normal illumination window and the abnormal illumination window at each angle are screened out; For any angle, if the sliding window is an abnormal illumination window, obtain the normal illumination window corresponding to the abnormal illumination window at other angles as the target window; obtain the mean of the illumination uniformity of all target windows as the first mean; obtain the mean of the initial light scattering intensity of all target windows at the corresponding angles as the second mean; obtain the ratio of the first mean to the illumination uniformity of the abnormal illumination window at the corresponding angle, and calculate the product between the ratio result and the second mean as the corrected intensity weight; Obtaining the sum of the initial light scattering intensity and the corrected intensity weight at the corresponding angle of each abnormal illumination window as the corrected light scattering intensity of each abnormal illumination window at the corresponding angle; If the sliding window is a normal illumination window, the initial light scattering intensity at the corresponding angle of the sliding window is used as the corrected light scattering intensity.

9. A method for testing particle size distribution of mineral fire retardant powder according to claim 8, characterized in that: The screening out of the normal illumination window and the abnormal illumination window at each angle includes: For any angle, if the illumination uniformity of the sliding window is less than the preset uniformity threshold, the corresponding sliding window is regarded as an abnormal illumination window; if the illumination uniformity of the sliding window is greater than or equal to the preset uniformity threshold, the corresponding sliding window is regarded as a normal illumination window.

10. A method for testing particle size distribution of mineral fire retardant powder according to claim 1, characterized in that: The method for obtaining the overall light scattering intensity comprises: Obtaining a ratio of the corrected light scattering intensity to the initial light scattering intensity of each sliding window at each angle as an intensity ratio; Calculate the product of the initial light scattering intensity of the sliding window at the corresponding angle of each fire retardant powder particle and the intensity ratio as the local light scattering intensity of the sliding window at the corresponding angle of each fire retardant powder particle; The corrected light scattering intensity of the sliding window of the same fire retardant powder particle at different angles is averaged to be the overall light scattering intensity of each fire retardant powder particle.

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