An apparatus and method for detecting airborne dust particles in an environment

Abstract

The present application relates to particle concentration detection technical field, specifically to a kind of detection device and method of air dust particle in environment, comprising: obtaining the particle concentration of each particle size of dust particle in air at each time, each time corresponds a preset reference period before;According to the difference distribution and data fluctuation of the particle concentration of each particle size in preset reference period at each time, all times are screened to determine the relative zero point concentration of each particle size after stable time;According to the relative distribution between the particle concentration of each particle size in the preset reference period corresponding to stable time and the relative zero point concentration of stable time, residual coefficient is obtained;According to residual coefficient, relative zero point concentration and the consistency relationship between the relative zero point concentration of each particle size and other particle size, the particle concentration of each particle size is corrected to obtain the actual concentration of each particle size.The present application can effectively remove the influence of zero drift, and the concentration detection result is more accurate.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of particle concentration detection, and particularly to a device and method for detecting air dust particles in an environment. BACKGROUND

[0002] The principle of detecting air dust particles by using the laser scattering principle is that an air pump collects air to pass through the measuring cavity to stabilize the air flow. The optical system of the instrument causes the laser to irradiate into the measuring cavity. When the dust in the air passes through the laser, a part of the light signal is scattered. By collecting and analyzing the intensity of the scattered light signal, the size and number of particles can be monitored in real time, and the concentration value of different particle diameters can be converted.

[0003] In the process of detecting air dust particles, the optical lenses and other components of the instrument may be contaminated by dust particles in the air, resulting in fixed noise in the detection results and causing zero drift. In the prior art, the zero drift correction is often performed at a fixed time interval, for example, at 4 a.m. every day to create a relatively stable zero point environment to obtain the degree of zero drift. However, this method cannot determine the quality of the air when creating the zero point environment. If the air is severely polluted at this time, the particle concentration is high, and the degree of zero drift obtained is greatly affected by the air, and cannot accurately represent the deviation of the system itself. SUMMARY

[0004] In order to solve the technical problem that the existing method uses a fixed time interval to perform zero drift operation on the particle detection concentration, resulting in inaccurate concentration detection, the purpose of the present application is to provide a device and method for detecting air dust particles in an environment, and the technical solution adopted is as follows:

[0005] In the first aspect, the present application provides a method for detecting air dust particles in an environment, comprising:

[0006] At each time, the particle concentration of each particle size of the dust particles in the air is obtained, and each time corresponds to a preset reference period before each time;

[0007] According to the difference distribution and data fluctuation of the particle concentration of each particle size in the preset reference period at each time, all times are screened to determine the relative zero concentration of each particle size after the stable time;

[0008] According to the relative distribution between the particle concentration of each particle size in the preset reference period corresponding to the stable time and the relative zero concentration of the stable time, the residual coefficient of the stable time affected by the air is obtained;

[0009] According to the residual coefficient, the relative zero-point concentration of each particle size, and the consistency relationship between each particle size and other particle sizes, the particle concentration of each particle size is corrected to obtain the actual concentration of each particle size.

[0010] Preferably, the relative zero-point concentration of each particle size after the stable time is determined by screening all time points according to the difference distribution of the particle concentration of each particle size in the preset reference period at each time point and the data fluctuation, and specifically includes:

[0011] According to the difference distribution between the particle concentration of the target particle size at each time point in the preset reference period of the selected time point and the particle concentration of the target particle size at all time points, and the particle concentration change trend of the target particle size in the preset reference period of the selected time point, a stability evaluation value of the selected time point is obtained.

[0012] The selected time point is any time point, and the target particle size is any particle size.

[0013] The time point corresponding to the stability evaluation value greater than or equal to the preset stability threshold value is regarded as the stable time point, and the particle concentration of each particle size in the preset window after the stable time point is obtained as the relative zero-point concentration of the corresponding particle size under the preset condition.

[0014] Preferably, the stability evaluation value of the selected time point is obtained according to the difference distribution between the particle concentration of the target particle size at each time point in the preset reference period of the selected time point and the particle concentration of the target particle size at all time points, and the particle concentration change trend of the target particle size in the preset reference period of the selected time point, and specifically includes:

[0015] The average of the particle concentration of the target particle size at all time points in the preset reference period of the selected time point is obtained as the equilibrium concentration of the target particle size at the selected time point.

[0016] The cumulative sum of the difference between the particle concentration of the target particle size at each time point in the preset reference period of the selected time point and the equilibrium concentration is obtained as the concentration difference coefficient of the target particle size at the selected time point, and the average of the concentration difference coefficients of all particle sizes at the selected time point is obtained as the global difference coefficient.

[0017] The trend coefficient of each particle size with respect to the particle concentration at the selected time point is obtained, and the product of the global difference coefficient and the trend coefficient is negatively correlated to obtain the stability evaluation value of the selected time point.

[0018] Preferably, the residual coefficient of the stable time point affected by air is obtained according to the relative distribution between the particle concentration of each particle size in the preset reference period corresponding to the stable time point and the relative zero-point concentration of the stable time point, and specifically includes:

[0019] The ratio between the average of the particle concentration of each particle size at all time points before the stable time point and the relative zero-point concentration is taken as the relative concentration ratio of each particle size at the stable time point; based on the relative concentration ratio of each particle size at the stable time point, clustering is performed on all particle sizes to obtain a plurality of clustering clusters;

[0020] According to the distribution number of particle sizes in each clustering cluster and the distribution of the relative concentration ratio of all particle sizes in each clustering cluster, a consistency evaluation value of each clustering cluster is obtained.

[0021] According to the difference between the consistency evaluation value of the clustering cluster where each particle size is located, the relative concentration ratio of each particle size and the preset standard ratio, a residual coefficient of the stable time point affected by air is obtained.

[0022] Preferably, the consistency evaluation value of each clustering cluster is obtained according to the distribution number of particle sizes in each clustering cluster and the distribution of the relative concentration ratio of all particle sizes in each clustering cluster, specifically comprising:

[0023] The range of the relative concentration ratio of all particle sizes in the selected clustering cluster is obtained as a first difference range; the range of the relative concentration ratio of all particle sizes is obtained as a second difference range.

[0024] Based on the number of all particle sizes contained in the selected clustering cluster and the first difference range and the second difference range, the consistency evaluation value of the selected clustering cluster is determined; wherein the selected clustering cluster is any one of the clustering clusters.

[0025] Preferably, the residual coefficient of the stable time point affected by air is obtained according to the difference between the consistency evaluation value of the clustering cluster where each particle size is located, the relative concentration ratio of each particle size and the preset standard ratio, specifically comprising:

[0026] The relative concentration difference between the relative concentration ratio of each particle size and the preset standard ratio is obtained; the relative concentration difference of each particle size is weighted by using the consistency evaluation value of the clustering cluster where each particle size is located to obtain the residual coefficient of the stable time point affected by air.

[0027] Preferably, the method for obtaining the preset standard ratio is specifically:

[0028] The average of the relative concentration ratio of all particle sizes in the clustering cluster corresponding to the maximum value of the consistency evaluation value is taken as the preset standard ratio.

[0029] Preferably, the actual concentration of each particle size is obtained by correcting the particle concentration of each particle size according to the residual coefficient, the relative zero-point concentration of each particle size and the consistency relationship between the relative zero-point concentrations of each particle size and other particle sizes, specifically comprising:

[0030] determine the correction coefficient based on a negative correlation coefficient of a residual coefficient of the stable time affected by the air;

[0031] obtain the correction concentration of each particle size according to the correction coefficient, the relative zero point concentration of each particle size, and the consistency evaluation value of the cluster to which each particle size belongs;

[0032] take the difference between the particle concentration of each particle size at each time after the stable time and the correction concentration as the actual concentration of each particle size at each time.

[0033] Preferably, the step of obtaining the correction concentration of each particle size according to the correction coefficient, the relative zero point concentration of each particle size, and the consistency evaluation value of the cluster to which each particle size belongs specifically comprises:

[0034] take the product of the correction coefficient, the relative zero point concentration of each particle size, and the consistency evaluation value of the cluster to which each particle size belongs as the correction concentration of each particle size.

[0035] In a second aspect, the present application provides a device for detecting air dust particles in an environment, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, which, when executed by the processor, implements the steps of the method for detecting air dust particles in an environment.

[0036] The embodiments of the present application have at least the following beneficial effects:

[0037] The present application analyzes the stable state of the concentration based on the difference distribution and fluctuation of the particle concentration in the preset reference period before each time, dynamically obtains the stable time for correction and the relative zero point concentration that can reflect the system bias in the stable state, and combines the consistency of the concentration characteristics obtained after the stable time and the concentration characteristics before the stable time to obtain the air residual influence and exclude it in the zero point correction, so as to obtain more accurate zero point drift concentration results and more accurate zero point drift correction amount that can reflect the system bias itself, so that the actual concentration of each particle size after correction can effectively remove the influence of zero point drift, and the concentration detection result is more accurate. BRIEF DESCRIPTION OF DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, and the advantages thereof, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can obtain other drawings according to these drawings without any creative effort.

[0039] Figure 1 is a step flow chart of the method for detecting air dust particles in an environment provided by the present application;

[0040] Figure 2 is a step flow chart of the method for obtaining the stable moment air influence residual coefficient provided by the present application;

[0041] Figure 3 is a structural schematic diagram of the detection system for air dust particles in an environment provided by the present application. DETAILED DESCRIPTION

[0042] In order to further illustrate the technical means and effects taken by the present application to achieve the predetermined purposes, the following describes the detection device and method for air dust particles in an environment provided by the present application, the specific implementation, structure, features and effects thereof in detail in combination with the accompanying drawings and preferred embodiments. 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.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs.

[0044] The specific scheme of the detection device and method for air dust particles in an environment provided by the present application is specifically described below in combination with the accompanying drawings.

[0045] Please refer to Figure 1 which shows a step flow chart of the detection method for air dust particles in an environment provided by one embodiment of the present application, which includes the following steps:

[0046] Step S100, obtaining the particle concentration of air dust particles at each particle size at each moment, and each moment corresponds to a preset reference period.

[0047] As a specific example, the concentration of air dust particles in the environment is collected, specifically the suspended dust particles with a particle size below 10 microns. Each 0.5 micron is a particle size interval, and the particle concentration of all particles in each particle size interval below 10 microns is taken. It should be understood that one particle size corresponds to one particle size interval and one particle concentration.

[0048] As a specific example, the embodiment adopts an optical sensor based on the principle of laser scattering to collect particle concentration. The working principle is derived from the laser scattering effect. When laser irradiates dust particles in the air, the particles will scatter part of the light signal. The scattered light signal is collected by a photodetector and converted into an electrical signal, which is then transmitted to the controller module (microprocessor) for analysis, and finally the dust particle concentration of different particle sizes is converted. It should be noted that the collection method of particle concentration is a known technology, and will not be described in detail here. It should be understood that in other embodiments, the implementer can select other suitable particle size intervals or data collection methods according to the specific implementation scenario.

[0049] Further, to provide a data basis for subsequent evaluation of the data stability characteristics at each time, the embodiment forms a prediction reference period for each time from all times of a preset time length before each time, wherein the preset time length can be set to 10 minutes, and in other embodiments, the implementer can set it according to the specific implementation scenario. It should be noted that the stability analysis is not performed for the time that cannot obtain the preset time length.

[0050] Step S200, according to the difference distribution of particle concentration of each particle size in the preset reference period and the data fluctuation at each time, all times are screened to determine the relative zero point concentration corresponding to the stable time.

[0051] The core goal of this step is to get rid of the limitations of the fixed time correction in the prior art, and to accurately screen the time that meets the low interference and high stability conditions, that is, the stable time, by dynamically analyzing the particle concentration difference distribution and data fluctuation characteristics of each time in the preset reference period. Based on the stable time, the relative zero point concentration reflecting the system bias is obtained, which lays a reliable foundation for subsequent zero point drift correction.

[0052] First, the difference distribution of particle concentration of different particle sizes in the preset reference period of each time, such as whether each particle concentration is at a low level and matches each other, avoiding the abnormal high of a single particle size, and the data fluctuation of the concentration in the period, the air stability of each time is accurately judged.

[0053] Second, the time with the most stable air state and the least interference is screened from all monitoring times, and the relative zero point concentration representing the instrument bias is determined, which provides a reliable benchmark for the accurate correction of the subsequent zero point drift.

[0054] To this end, step S200 can be implemented by the following steps:

[0055] Step one, according to the difference distribution between the particle concentration of the target particle size at each time point in the preset reference period and the particle concentration of the target particle size at all time points, and the particle concentration variation trend of the target particle size in the preset reference period of the selected time point, the stability evaluation value of the selected time point is obtained. Wherein, the selected time point is any time point, and the target particle size is any particle size.

[0056] This embodiment takes any time point as an example, that is, any time point is taken as the selected time point, and any particle size is taken as the target particle size.

[0057] Zero point refers to the concentration reference point when the device does not carry out air detection. In an ideal state, by stopping air suction by closing the fan of the device, new particles can be blocked from entering the detection chamber; after standing treatment to make the existing particles in the detection chamber fully settle, the particle concentration of each particle size measured at this time is the relatively stable zero point value. However, in the actual environment monitoring scene, it is difficult to achieve a completely ideal zero point state. Therefore, based on the stable state of the concentration of each particle size at all time points in a period before each time point, the feasibility of constructing a zero point state by standing treatment after each time point is evaluated.

[0058] First step, the average value of the particle concentration of the target particle size at all time points in the preset reference period of the selected time point is obtained as the equilibrium concentration of the target particle size at the selected time point.

[0059] It should be understood that each particle size at each time point corresponds to a particle concentration, and the equilibrium concentration reflects the equilibrium condition of the particle concentration of any particle size in a period before the selected time point.

[0060] Second step, the cumulative sum of the difference between the particle concentration of the target particle size at each time point in the preset reference period of the selected time point and the equilibrium concentration is obtained as the concentration difference coefficient of the target particle size at the selected time point; the average value of the concentration difference coefficients of all particle sizes at the selected time point is taken as the global difference coefficient.

[0061] As a specific example, the tth time point is taken as the selected time point, and the global difference coefficient corresponding to the selected time point can be expressed by the formula:

[0062]

[0063] Wherein, represents the global difference coefficient corresponding to the selected time point, t represents the tth time point, that is, the selected time point; represents the particle concentration of the nth particle size at the ith time point in the preset reference period before the selected time point, represents the average value of the particle concentration of the nth particle size at all time points in the preset reference period corresponding to the selected time point, that is, the equilibrium concentration of the nth particle size at the selected time point, represents the number of time points contained in the preset reference period, represents the concentration difference coefficient of the nth particle size at the selected time point, represents an averaging function for calculating the average of the concentration difference coefficients of all particle sizes.

[0064] equilibrium concentration reflects the overall concentration level of the nth particle size in the preset reference period, reflects the relative deviation between the particle concentration at each time point and the equilibrium concentration, in this embodiment, in order to avoid the deviation of the high concentration particle size being excessively enlarged, the ratio between the relative deviation and the equilibrium concentration is used reflects the difference between the particle concentration at each time point and the equilibrium concentration, that is, reflects the proportion of the relative deviation, and then calculates the cumulative sum of the relative fluctuation , and finally the deviations of multiple particle sizes are comprehensively analyzed by using the averaging method.

[0065] The global difference coefficient is used to evaluate the fluctuation of the particle concentration of multiple particle sizes at the selected time point from the perspective of the relative fluctuation of the concentration. The smaller the value is, the more stable the overall concentration is before the selected time point. From the spatial dimension (all particle sizes), the air stability is comprehensively evaluated. If only one or a few particle sizes have small fluctuations and other particle sizes have large fluctuations, it indicates that the air state is still disturbed by local interference (such as temporary dust source), which does not meet the requirement of overall stability at the stable time point. Only when the average fluctuation of all particle sizes is small, it can be proved that the air is in a low-interference and stable state in the preset reference period.

[0066] In the third step, the trend coefficient of each particle size with respect to the particle concentration at the selected time point is obtained, and the product of the global difference coefficient and the trend coefficient is negatively correlated to obtain the stability evaluation value at the selected time point.

[0067] Specifically, at the selected time point, each particle size corresponds to a particle concentration. The particle concentration of all particle sizes at the selected time point is linearly fitted with the particle size as the horizontal coordinate and the particle concentration as the vertical coordinate, and the absolute value of the slope of the fitted straight line is taken as the trend coefficient of the particle size with respect to the particle concentration at the selected time point. The least square method can be used for linear fitting, which is a known technology and will not be described in detail here. In other embodiments, the implementer can select other suitable fitting methods according to the specific implementation scene.

[0068] The absolute value of the slope of the fitting straight line reflects the size of the trend of particle concentration with the increase or decrease of particle concentration, the smaller the trend coefficient, the less obvious the upward trend or downward trend of particle concentration in the preset reference period at the selected time, and thus the air is more stable. The greater the value of the trend coefficient, the greater the trend of particle concentration in the preset reference period at the selected time, the greater the air fluctuation, and the worse the stability.

[0069] Finally, the product of the global difference coefficient and the trend coefficient corresponding to the selected time is processed by negative correlation in the form of to obtain the stability evaluation value of the selected time, represents an exponential function with the natural constant e as the base, represents the slope of the fitting straight line corresponding to the preset reference period corresponding to the selected time, represents the trend coefficient of the particle size with the change of the particle concentration at the selected time, represents the global difference coefficient corresponding to the selected time, t represents the tth time, that is, the selected time.

[0070] The stability evaluation value evaluates the air stability at the corresponding time from two aspects of particle concentration fluctuation and particle concentration trend at each time, and the greater the value, the greater the reliability of the zero point state of the particle concentration constructed at the time.

[0071] Step two, the time corresponding to the stability evaluation value greater than or equal to the preset stability threshold is regarded as the stable time. After obtaining the stable time under the preset condition, the particle concentration of each particle size in the preset window is regarded as the relative zero point concentration of the corresponding particle size.

[0072] If the environmental air pollution degree is high (i.e. the particle concentration is high), the estimated relative zero point value will be high when the zero point state is constructed under this condition, which will finally adversely affect the accuracy of all subsequent detection results. In order to effectively reduce the error of the relative zero point state, it is necessary to ensure that the particle concentration of the environment itself is at a low level and remains stable, so all times are screened by the stability evaluation value to select the time with high air stability and low interference.

[0073] In the embodiment, the value of the stability threshold is set to 0.7, which can be set according to the specific implementation scene. The stability evaluation value at each time is obtained in real time. When the stability evaluation value at the t th time is greater than or equal to the stability threshold, it indicates that the influence degree of the environmental factor at the time is small, and the reliability of the zero point state of the particle concentration constructed at the time is large. At this time, 30s starting from the t th time is taken as the correction window, the device fan is turned off and is placed for 30s, and the particle concentration of each particle size after being placed for 30s is obtained, which is recorded as the relative zero point concentration of each particle size. The relative zero point concentration represents the particle concentration value of the system still existing in the relatively stable air state.

[0074] It should be understood that the preset condition refers to the particle concentration collection operation after the device fan is turned off and is placed for 30s in the preset window. In other embodiments, the implementer can set it according to the specific implementation scene. The core purpose of this operation is to maximize the exclusion of external air interference, so that the measured relative zero point is closer to the deviation of the system itself rather than the influence of air residue.

[0075] After the stable time is determined, the concentration at the time cannot be directly used as the relative zero point concentration. On the one hand, the real-time air at the stable time may still have a small amount of particles that have not settled; on the other hand, the instrument detection cavity needs to be placed for a certain time to ensure that no new particles enter and the original particles are fully settled. Therefore, a preset window (the value of which is 30s in the embodiment) after the stable time is set, and the particle concentration of each particle size after being placed is collected. At this time, the concentration has excluded the real-time air interference to the greatest extent, is closer to the background concentration generated by the instrument due to its own pollution, and can be used as the relative zero point concentration of the corresponding particle size, providing accurate basic data for the final zero point drift correction.

[0076] It should be noted that the essence of the zero point concentration is the fixed measurement noise caused by the system itself defects. The relative zero point concentration obtained in the embodiment is essentially a preliminary zero point actually measured, which mainly contains two components. On the one hand, it contains the zero point drift value of the system itself, and on the other hand, it contains the air influence value, that is, the air interference component, such as a small amount of external particles that have not completely settled in the cavity. Therefore, the relative zero point concentration needs to be further analyzed to obtain the true zero point value without the air interference part.

[0077] In step S300, a residual coefficient of the stable time affected by the air is obtained according to the relative distribution between the particle concentration of each particle size in the preset reference period corresponding to the stable time and the relative zero point concentration at the stable time.

[0078] The core role of the residual coefficient is to quantify the proportion of the air residual impact in the relative zero-point concentration, which lays the foundation for subsequent exclusion of the impact and accurate extraction of the system itself zero-point drift. Three key problems need to be solved, such as how to distinguish air residual and system drift, how to quantify the influence difference of different particle sizes, and how to integrate multi-dimensional features to obtain the overall influence degree. Figure 2 As shown in FIG. 3, the method for obtaining the air influence residual coefficient at the stable moment can be realized by steps S301 to S303.

[0079] In the first aspect, there is an essential difference between the air residual impact and the system zero-point drift in the action law of different particle sizes. Therefore, the relative distribution between the particle concentration of each particle size and the relative zero-point concentration is needed to separate the particle size groups with similar characteristics.

[0080] The essence of the air residual impact is the residual of the air particles in the detection cavity that have not completely settled, and the concentration distribution should be consistent with the air concentration distribution before the stable moment, that is, the concentration proportion of different particle sizes is unchanged. The system zero-point drift is a fixed noise caused by the contamination of the optical lens and other equipment problems, and the concentration distribution is irrelevant to the previous air concentration (the noise size of different particle sizes may be random). If the overall analysis of all particle sizes is directly performed, the air residual impact with consistent proportion and the system drift with chaotic proportion will be confused, and the particle size range corresponding to the air residual cannot be accurately located. Therefore, the relative concentration proportion is calculated first, and then clustering is performed to form a clustering cluster composed of particle sizes with similar characteristics. The particle sizes in the same cluster are more likely to be dominated by the same factor (air residual or system drift), which provides a classification basis for subsequent targeted analysis.

[0081] In step S301, the ratio between the average particle concentration of each particle size at all times before the stable moment and the relative zero-point concentration is taken as the relative concentration proportion of each particle size at the stable moment. Based on the relative concentration proportion of each particle size at the stable moment, clustering is performed on all particle sizes to obtain a plurality of clustering clusters.

[0082] The quantification process of the relative concentration proportion of each particle size at the stable moment represents the process of extracting the concentration proportion feature, which provides a quantitative basis for distinguishing the air residual impact and the zero-point drift impact in the subsequent process.

[0083] As a specific example, the AP clustering algorithm is used in this embodiment. Based on the difference in the relative concentration proportion between different particle sizes at the stable moment, clustering is performed on all particle sizes to obtain a plurality of clustering clusters, each of which contains a plurality of particle sizes with similar relative concentration proportions. When the relative zero-point concentration is only affected by the air residual impact, the distribution of the relative zero-point concentration should be similar to the particle concentration feature before the stable moment, and the relative concentration relationship between different particle sizes is basically unchanged, that is, the relative concentration proportions of different particle sizes are close to each other.

[0084] In a second aspect, the consistency of the relative concentration ratios of the particle sizes in the cluster directly reflects the possibility of being affected by the air residual, and the consistency evaluation value is used to quantify this characteristic. It should be understood that not all clusters correspond to the air residual effect: if the relative concentration ratios of the particle sizes in a cluster are very small, it means that the concentration variation rules of these particle sizes are highly unified, which is consistent with the characteristics of the proportion being unchanged under the air residual effect; if the relative difference in a cluster is extremely large, it means that the concentration variation of these particle sizes has no unified rule, and it is more likely to be caused by system drift. Further, in combination with the number of particle sizes in the cluster (reflecting the influence coverage) and the range of the proportion in the cluster (reflecting the internal consistency), the degree to which each cluster conforms to the air residual characteristics is quantified, and the consistency evaluation value is introduced. The higher the consistency evaluation value, the higher the reliability of the particle sizes in the cluster being affected by the air residual, which provides a basis for determining the standard proportion (the reference characteristic of the air residual) in the subsequent step.

[0085] In step S302, the consistency evaluation value of each cluster is obtained according to the number of the particle sizes in each cluster and the distribution of the relative concentration ratios of all the particle sizes in each cluster.

[0086] Specifically, the range of the relative concentration ratios of all the particle sizes in the selected cluster is obtained as a first difference range; the range of the relative concentration ratios of all the particle sizes is obtained as a second difference range; the consistency evaluation value of the selected cluster is determined based on the number of all the particle sizes contained in the selected cluster and the first difference range and the second difference range; and the selected cluster is any one of the clusters.

[0087] As a specific example, any one of the clusters is taken as an example for illustration, for example, the mthcluster is taken as the selected cluster, and the method for obtaining the consistency evaluation value of the selected cluster can be expressed by the following formula:

[0088]

[0089] wherein, represents the consistency evaluation value of the mthcluster, and m represents the mthcluster, i.e., the selected cluster; represents the number of the particle sizes contained in the mthcluster, represents the maximum value of the relative concentration ratios of all the particle sizes in the mthcluster, represents the minimum value of the relative concentration ratios of all the particle sizes in the mthcluster; represents the maximum value of the relative concentration ratios of all the particle sizes, represents the minimum value of the relative concentration ratios of all the particle sizes, represents an exponential function with the natural constant e as the base.

[0090] represents the first difference range, reflecting the range size degree of the relative concentration proportion of the overall particle size in the mth cluster, represents the second difference range, reflecting the range size degree of the relative concentration proportion of all particle sizes. reflects the difference proportion of the relative concentration proportion in the mth cluster.

[0091] The more particle sizes contained in the cluster, the smaller the difference proportion, indicating that the concentration change proportions of all particle sizes in the same cluster are more consistent before and after the stable time, that is, the relative concentration proportion characteristic distribution is more similar, and the particle size range covered is wider, thereby indicating that the particle sizes in the cluster follow the same concentration change rule, which conforms to the core characteristics of residual air influence. The consistency evaluation value characterizes whether the corresponding concentration change characteristics of the particle sizes contained in the corresponding cluster conform to the degree of residual air influence, and the larger the value, the more consistent the concentration change proportion relationship of all particle sizes, and the greater the possibility of residual air influence. The smaller the value, the greater the difference in the concentration change proportion relationship of all particle sizes, and the greater the possibility of system zero drift bias influence.

[0092] The higher the consistency evaluation value of the cluster, the more likely the concentration characteristics of the particle sizes in the cluster are mainly affected by residual air rather than system bias zero drift. Therefore, when adjusting the detection results by the relative zero point concentration, attention needs to be paid to the residual air influence. When a particle concentration does not exist zero drift, there is residual air influence leading to the relative zero point concentration not being 0, and if the relative zero point concentration is mistakenly judged as zero drift at this time, it will lead to errors in the subsequent detection results. Therefore, by excluding the part affected by residual air from the relative zero point concentration through the residual air influence characteristics, more accurate zero drift correction is achieved.

[0093] In a third aspect, the residual coefficient comprehensively considers the influence credibility of different particle sizes and the degree of deviation of particle sizes from the reference characteristics, and can comprehensively reflect the overall influence of air residue. The consistency evaluation value of a single cluster can only indicate the influence of local particle sizes, while the residual coefficient needs to depict the comprehensive effect of air residue on all particle sizes at the stable time; at the same time, different particle sizes deviate from the reference characteristics of air residue to different degrees, and the smaller the deviation, the more significant the influence of air residue, and the larger the deviation, the more likely it is system drift. If only the consistency evaluation value is used, the deviation difference of particle sizes from the reference will be ignored; if only the deviation difference is used, the influence credibility of different particle sizes will be ignored. Therefore, the residual coefficient comprehensively reflects the overall influence degree of air residue through the analysis results of two dimensions.

[0094] In step S303, the residual coefficient of the stable time affected by air is obtained according to the consistency evaluation value of each particle size in the cluster, the difference between the relative concentration proportion of each particle size and the preset standard proportion.

[0095] Specifically, in the first step, the relative concentration difference between the relative concentration ratio of each particle size and the preset standard ratio is obtained.

[0096] More specifically, the mean of the relative concentration ratios of all particle sizes in the cluster corresponding to the maximum of the consistency evaluation value is taken as the preset standard ratio.

[0097] The consistency evaluation value of each cluster represents the aggregation state of the concentration change of different particle sizes before and after the stable moment. Since the residual air and the air before the stable moment do not cause a sudden change in composition, the concentration changes of different particle sizes are basically consistent. Therefore, the more the aggregation degree of the cluster in the clustering result and the more the number of particle sizes contained in the cluster, the greater the influence of the residual air on the particle sizes contained in the cluster. That is, the greater the value of the consistency evaluation value of the clustering cluster, the more consistent the concentration change ratio relationship of all particle sizes in the corresponding clustering cluster, the greater the possibility of being affected by the residual air. Therefore, the clustering cluster corresponding to the maximum of the consistency evaluation value is selected, and the clustering cluster is the most likely particle size cluster affected by the residual air. The average particle size level of the clustering cluster represents the standard ratio change relationship affected by the residual air.

[0098] In the second step, the relative concentration difference of each particle size is weighted using the consistency evaluation value of the clustering cluster where the particle size is located, to obtain the residual coefficient of the stable moment affected by the air.

[0099] As a specific example, the method for obtaining the residual coefficient of the stable moment affected by the air can be expressed by the formula:

[0100]

[0101] wherein, represents the residual coefficient of the stable moment affected by the air, represents the consistency evaluation value of the clustering cluster where the dth particle size is located, represents the relative concentration ratio of the dth particle size, represents the preset standard ratio, represents the number of all particle sizes, represents the Sigmoid function, which is used for positive ratio normalization.

[0102] represents the relative concentration difference corresponding to the dth particle size, which reflects the relative deviation degree of the relative concentration ratio of the dth particle size from the standard condition. The smaller the deviation, the more significant the influence of the residual on the particle size. The greater the deviation, the more significant the system deviation.

[0103] The relative concentration difference is weighted using the consistency evaluation value of the clustering cluster where the particle size is located The relative concentration difference is weighted using the consistency evaluation value of the clustering cluster where the particle size is located The higher the particle size, the more likely to be affected by the residual, the deviation of the overall residual impact of the contribution weight is greater, consistent evaluation value The lower the particle size, the more likely to be affected by the system deviation, the contribution weight of the deviation is smaller.

[0104] Indicates the use of particle size in the cluster of consistent evaluation value The average deviation is obtained by weighting and averaging the relative concentration difference. The smaller the ratio, the closer the overall particle size relative concentration ratio to the standard situation, and the more significant the air residual impact. The larger the ratio, the more the overall particle size relative concentration ratio deviates from the standard situation, and the weaker the air residual impact.

[0105] The performance of the relative concentration ratio corresponding to the particle size cluster most likely to be affected by the residual is taken as the standard. The deviation of all particle sizes from the standard is calculated by weighting, and the interference degree, i.e. the residual coefficient, is finally normalized. The residual coefficient reflects the influence of the dust particle concentration in the air before the correction window on the relative zero point concentration at the stable time, avoiding the relative zero point concentration being too high due to the residual impact of the air.

[0106] At this point, the residual coefficient of the stable time affected by the air is essentially a quantitative characterization of the air residual impact mixed in the relative zero point concentration, laying a foundation for subsequent elimination of the interference and obtaining the true system zero drift.

[0107] Step S400, according to the residual coefficient, the relative zero point concentration of each particle size, and the consistency relationship between the relative zero point concentrations of each particle size and other particle sizes, the particle concentration of each particle size is corrected to obtain the actual concentration of each particle size.

[0108] In the first aspect, the residual coefficient directly reflects the strength of the air residual impact, and the core goal of correction is to exclude the impact and retain the system's own zero drift error. The larger the residual coefficient, the higher the proportion of the relative zero point concentration affected by the air residual, and the more the air residual part needs to be excluded. Conversely, the smaller the residual coefficient, the weaker the air residual impact, and the less the part needs to be excluded. The residual coefficient needs to be converted into a correction coefficient inversely related to the air residual impact to ensure that when the residual coefficient increases, the correction coefficient adjusts in the direction of weakening the air residual impact, providing an adaptive adjustment benchmark for subsequent accurate calculation of system drift error (corrected concentration).

[0109] In the second aspect, the degree of influence of different particle sizes by air residues is different, and the adjustment range needs to be distinguished in combination with the consistent evaluation value to avoid errors caused by one-size-fits-all correction. The greater the consistent evaluation value, the more consistent the concentration change of the cluster where the particle size is located with the air residue characteristics (proportionally consistent), and the higher the proportion of air residues in the relative zero point concentration. The smaller the consistent evaluation value, the more likely the particle size is dominated by system drift, and the lower the proportion of air residues. If only the correction coefficient and the relative zero point concentration are used to calculate the corrected concentration, the difference between particle sizes will be ignored. For example, the particle size with a consistent evaluation value of 0.9 needs to significantly weaken the influence of air residues, and the particle size with a consistent evaluation value of 0.3 only needs to be adjusted slightly. Therefore, the consistent evaluation value needs to be integrated as a weight factor into the calculation of the corrected concentration to dynamically adapt the correction process according to the influence attributes of different particle sizes, and to ensure that the corrected concentration of each particle size only reflects the zero point drift of the system itself, rather than air residue interference.

[0110] In the third aspect, the detection concentration contains three types of components, including the environmental real particle concentration, the system zero point drift error, and the air residue influence. The error needs to be offset by subtracting the corrected concentration from the detection concentration to obtain the real concentration. The corrected concentration is the error value that only reflects the system zero point drift after excluding the air residue, and the detection concentration is the superimposed result of the three. If the environmental real particle concentration is to be separated out, the actual detection concentration needs to be subtracted from the corrected concentration to realize the concentration performance of offsetting the system zero point drift error.

[0111] To this end, the method for obtaining the actual concentration of each particle size can be implemented by the following steps.

[0112] In the first step, the correction coefficient is determined based on the negative correlation coefficient of the residual coefficient affected by air at the stable time.

[0113] In this embodiment, the residual coefficient is a normalized value, so the correction coefficient in this embodiment is

[0114] In the second step, the corrected concentration of each particle size is obtained according to the correction coefficient, the relative zero point concentration of each particle size, and the consistent evaluation value of each particle size in the clustering cluster.

[0115] Specifically, the product of the correction coefficient, the relative zero point concentration of each particle size, and the consistent evaluation value of each particle size in the clustering cluster is taken as the corrected concentration of each particle size.

[0116] The product operation core is to realize the synergistic effect of overall air residue stripping and particle size attribute adaptation, which conforms to the physical law that the influence of air residues and system drift on the relative zero point concentration is a multiplicative superposition relationship.

[0117] ​At this point, by creating a zero point environment in a relatively stable air state, combined with the residual effect of air, a correction concentration for adjusting the concentration detection result is obtained, which represents the concentration value reflecting only the system itself zero point drift error after excluding the residual effect of air.

[0118] In the third step, the difference between the particle concentration of each particle size at each time after the stable time and the correction concentration is taken as the actual concentration of each particle size at each time.

[0119] The particle concentration of each particle size at each time represents the real-time collected data of each particle size, and the concentration value after eliminating the system itself zero point drift error of the real-time collected data can reflect the true concentration of each particle size.

[0120] It should be noted that after the end of the preset window after the stable time and the device returns to normal detection (fan restart, continuous air collection), the real-time concentration collected at each subsequent time needs to be calculated as the actual concentration by the difference between the particle concentration and the correction concentration, that is, the correction concentration only takes effect on the real-time data after the preset window of the stable time, and does not correct the historical data before the stable time (to avoid destroying the coherence of historical data).

[0121] In other embodiments, the update interval of the correction concentration can also be set, for example, 12 hours. When the time interval between the end time of the preset window of the last stable time and the current time is less than 12 hours, the update operation of the correction concentration is not triggered, avoiding the influence of frequent zero point changes on data coherence. When the time interval between the end time of the preset window of the last stable time and the current time is greater than or equal to 12 hours, the update interval is met, and the correction concentration can be recalculated according to the method steps to correct the zero point drift and obtain more accurate detection results. It should be understood that the implementer of the update interval can set it according to the specific implementation scene.

[0122] In summary, the embodiment dynamically obtains the stable time for correction based on the stable state of air concentration in the continuous time before each time, and obtains the air residual effect and excludes it in the zero point correction by combining the consistency of the concentration characteristics obtained after the stable time and the concentration characteristics before the stable time, so as to obtain more accurate zero point drift concentration results and obtain the zero point drift correction amount that can better reflect the system itself deviation.

[0123] The embodiment of the present application also provides a detection device for air dust particles in an environment, which comprises a memory, a processor, and a computer program stored in the memory and running on the processor, and the computer program realizes the steps of the detection method for air dust particles in an environment when executed by the processor. Since the detection method for air dust particles in an environment has been described in detail, it will not be introduced here.

[0124] As Figure 3 shown, the embodiment of the present application also provides a detection system for air dust particles in an environment, comprising a sensor module, a display module, a communication module, a power module and a controller module.

[0125] The sensor module mainly comprises a laser diode, an optical lens group, a photodetector and a fan. Based on the principle of laser scattering, the laser diode is used to irradiate particles in the air, collect scattered light signals and convert them into electrical signals, which are transmitted to the controller module. More specifically, the sensor module is used to obtain the particle concentration of each particle size in real time. That is, it is used to implement step S100 in the method embodiment.

[0126] The controller module contains a microprocessor responsible for controlling sensor sampling, running core algorithms, managing communication, etc. The signals collected by the optical sensor are processed and analyzed, and then the concentration data of each particle size of the real-time environmental air is output. That is, the controller module is mainly used for data processing operation, and is used to implement steps S200 to S400 in the method embodiment.

[0127] The power module is used to maintain the normal operation of the device.

[0128] The display module visualizes the real-time particle size-concentration data.

[0129] The communication module is used to realize real-time uploading of data to the cloud platform or central server, and exchange of external data with the cloud platform, such as receiving remote control information from the cloud platform.

[0130] The above-described embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacements for some technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A method for detecting airborne dust particles in an environment, characterized in that, The method includes the following steps: At each moment, the concentration of dust particles of each size in the air is obtained, and a preset reference time period is corresponding to each moment. Based on the difference distribution and data fluctuation of particle concentration for each particle size in the preset reference period at each time, all time points are screened to determine the relative zero point concentration of each particle size after the stable time. Based on the relative distribution between the particle concentration of each particle size within the preset reference time period corresponding to the stable moment and the relative zero point concentration at the stable moment, the residual coefficient of the stable moment affected by air is obtained. Based on the residual coefficient, the relative zero-point concentration of each particle size, and the consistency relationship of the relative zero-point concentration between each particle size and other particle sizes, the particle concentration of each particle size is corrected to obtain the actual concentration of each particle size. The residual coefficient of air influence at the stable moment is obtained based on the relative distribution of particle concentration of each particle size within a preset reference time period corresponding to the stable moment and the relative zero-point concentration at the stable moment. Specifically, this includes: The ratio between the mean of particle concentration at all times for each particle size before the steady-state time and the relative zero-point concentration is taken as the relative concentration ratio of each particle size at the steady-state time; the mean of the relative concentration ratios of all particle sizes in the cluster corresponding to the maximum value of the consensus evaluation value is taken as the preset standard ratio. Based on the relative concentration ratio of each particle size at the steady moment, all particle sizes are clustered to obtain several clusters; The range of the relative concentration ratios of all particle sizes in the selected cluster is obtained as the first difference range; the range of the relative concentration ratios of all particle sizes is obtained as the second difference range; based on the number of all particle sizes included in the selected cluster, as well as the first and second difference ranges, the consistency evaluation value of the selected cluster is determined; wherein the selected cluster is any cluster. The formula for calculating the consensus evaluation value of the selected cluster is as follows: in, This represents the consensus evaluation value of the m-th cluster, where m represents the m-th cluster, which is also the selected cluster. This represents the number of particle sizes contained in the m-th cluster. This represents the maximum relative concentration ratio of all particle sizes in the m-th cluster. This represents the minimum relative concentration ratio of all particle sizes in the m-th cluster; This represents the maximum value of the relative concentration ratio for all particle sizes. This represents the minimum relative concentration ratio for all particle sizes. This represents an exponential function with the natural constant e as its base. Obtain the relative concentration difference between the relative concentration ratio of each particle size and the preset standard ratio; using the consistent evaluation value of the cluster to which each particle size belongs, weight the relative concentration difference of each particle size to obtain the residual coefficient of air influence at the steady moment. The formula for calculating the residual coefficient is as follows: in, This represents the residual coefficient affected by air at a steady state. This represents the consensus evaluation value of the cluster to which the d-th particle size belongs. This represents the relative concentration ratio of the d-th particle size. Indicates the preset standard ratio. Indicates the number of all particle sizes. This represents the Sigmoid function, used for proportional normalization. The step of correcting the particle concentration for each particle size based on the residual coefficient, the relative zero-point concentration for each particle size, and the consistency relationship of the relative zero-point concentration between each particle size and other particle sizes to obtain the actual concentration for each particle size specifically includes: The correction coefficient is determined based on the negative correlation coefficient of the residual coefficient affected by air at the steady moment; the formula for calculating the correction coefficient is as follows: ; The product of the correction factor, the relative zero-point concentration for each particle size, and the consensus evaluation value of the cluster to which each particle size belongs is used as the correction concentration for each particle size. The difference between the particle concentration of each particle size at each time step after the stabilization time and the corrected concentration is taken as the actual concentration of each particle size at each time step.

2. The method for detecting airborne dust particles in an environment according to claim 1, characterized in that, The step of filtering all time points based on the difference distribution and data fluctuation of particle concentration for each particle size within a preset reference time period, and determining the relative zero-point concentration for each particle size after the stable time point, specifically includes: Based on the difference distribution between the target particle size and the particle concentration of the target particle size at each time point and at all times in the preset reference period at the selected time point, and the trend of the particle concentration of the target particle size in the preset reference period at the selected time point, a stable evaluation value for the selected time point is obtained. Wherein, the selected time is any time, and the target particle size is any particle size; The moment when the stability evaluation value is greater than or equal to the preset stability threshold is taken as the stability moment. After obtaining the stability moment under preset conditions, the particle concentration of each particle size within the preset window is taken as the relative zero point concentration of the corresponding particle size.

3. The method for detecting airborne dust particles in an environment according to claim 2, characterized in that, The method of obtaining a stable evaluation value for a selected time based on the difference distribution between the target particle size at each time point and the particle concentration of the target particle size at all times within a preset reference period, and the trend of particle concentration change of the target particle size within the preset reference period, specifically includes: The average particle concentration of the target particle size at all times in the preset reference time period at the selected time is obtained as the equilibrium concentration of the target particle size at the selected time. The concentration difference coefficient of the target particle size at the selected time is obtained by summing the differences between the particle concentration and the equilibrium concentration of the target particle size at each time in the preset reference period of the selected time; the average of the concentration difference coefficients of all particle sizes at the selected time is used as the global difference coefficient. Obtain the trend coefficient of each particle size as a function of particle concentration at a selected time point, and perform negative correlation processing on the product between the global difference coefficient and the trend coefficient to obtain the stable evaluation value at the selected time point.

4. A device for detecting airborne dust particles in an environment, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that, When the computer program is executed by the processor, it implements the steps of the method for detecting airborne dust particles in an environment as described in any one of claims 1-3.

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