An ultraviolet-induced fluorescence-based optical system and method for measuring micro-physical parameters of insect-pollinated pollen, and a pollen injection device

Abstract

The present application relates to a kind of based on ultraviolet-induced fluorescence insect pollination pollen microphysical parameter measurement optical system, measurement method and pollen blowing device, by building coaxial orthogonal light path synchronous acquisition system, the specificity identification and accurate counting of insect pollination pollen are realized, the technical pain points such as particle overlap, signal interference, inaccurate identification, large counting deviation in the existing pollen measurement are solved, and finally the number concentration of insect pollination pollen is accurately output.

Description

Technical Field

[0001] This invention belongs to the fields of agricultural monitoring, ecological environment monitoring, and pollen microphysical property measurement technology. Specifically, it relates to an optical system and method for measuring the microphysical parameters of insect-pollinated pollen based on ultraviolet-induced fluorescence, as well as a method for screening effective insect-pollinated pollen particles. Background Technology

[0002] In the field of agricultural and ecological monitoring, changes in the number concentration of insect-pollinated pollen are a core indicator characterizing the developmental status of crops during flowering, directly related to crop pollination efficiency and final yield. Among known technologies, current mainstream pollen detection techniques fall into two categories: one is the traditional manual microscopic examination method, which involves collecting samples, preparing and staining slides, and then manually counting pollen under a microscope—a cumbersome, time-consuming, and highly subjective process; the other is the optical aerosol detection method, which utilizes the principle of single-light scattering to determine particle size and count particles based on the intensity of scattered light. This is a general aerosol detection method and has not been specifically optimized for pollen characteristics.

[0003] One existing technology, the laser scattering real-time pollen detection system (Pan), is a device that records the scattered light signals from aerosol particles to achieve preliminary acquisition of particle size and visualization of individual particles. The core working principle of this device is based on the effects of light scattering and optical focusing. Specifically, the device emits a 532nm continuous laser and a 527nm pulsed laser. The former forms a focused light cone through optical devices, focusing and concentrating particles in the airflow through optical force; the latter continuously irradiates the particles, and the scattered light is captured by an ICCD detector, visualizing the particle trajectory. The approximate particle size and pollen concentration are obtained by inverting the scattered light signals from multiple angles. This proposed solution, a real-time pollen detection system using laser scattering, acquires particle size and pollen concentration information from multi-angle scattered light. However, it relies solely on scattered light signals for particle identification and lacks a recognition mechanism tailored to the specific characteristics of complex bioaerosol particles in the atmosphere. This results in low accuracy in distinguishing pollen particles from non-pollen particles of similar size (such as dust and other bioaerosol particles), leading to misidentification and miscounting. Consequently, it fails to accurately differentiate and identify pollen particles, failing to meet the core technical requirement of "accurate target particle identification" in atmospheric pollen monitoring. Furthermore, this solution employs a single-particle flow cytometry detection mode. To ensure that individual particles pass through the detection window sequentially, the flow rate of the gas to be measured must be deliberately slowed (the gas flow rate is only 0.6 L / min), directly resulting in a low overall system detection flow rate and a limited volume of gas sample that can be detected per unit time. This hinders the efficient capture of low-concentration pollen particles in the atmosphere, limiting its practical application in low-concentration pollen particle monitoring scenarios and failing to meet the technical requirement of "efficient and rapid target particle capture" for low-concentration pollen monitoring.

[0004] Another existing technology is the Huffman multi-particle spectrometer, a device that distinguishes between multiple aerosol particles and identifies biological particles based on optical dispersion imaging technology. The core working principle of this device is based on the dispersion and fluorescence excitation characteristics of light. Specifically, the device fixes a glass slide carrying pollen particles onto a microscope stage. By adjusting the angle of the excitation light source and the parameters of the transmission grating, the particles are illuminated from multiple angles, and dispersion signals are acquired. The particles generate intrinsic fluorescence under specific wavelength light excitation. The dispersion and fluorescence spectral signals are separated by an optical system, captured and analyzed by a detector, thereby achieving the distinction and identification of biological and non-biological multi-particle aerosols.

[0005] This scheme, namely the multi-particle spectrometer, has certain application value in the preliminary differentiation of multi-particle aerosols and the detection of pollen particle surface fluorescence. However, it still has limitations for the demand for efficient and automated real-time atmospheric pollen monitoring. Firstly, the detection mode of this system is limited by the mechanical carrier, which must rely on a glass slide as the only physical carrier medium for the sample. Moreover, the supporting detection system needs to integrate a high-precision mechanical rotating platform. This structure confines the entire detection process to a closed loop of "fixed carrier + mechanical movement," making it impossible to break away from the fixed physical framework for free and dynamic environmental monitoring. Consequently, the system cannot perform in-situ, real-time, and continuous online monitoring of pollen particles in the open atmospheric environment. There is a significant time delay and spatial separation in the process of pollen particles being captured from the air, placed on the glass slide, and then delivered to the detection area. At the same time, the detection efficiency is also limited by the speed of the mechanical platform. The time delay effect caused by mechanical movement limits the sample throughput that can be processed per unit time to a theoretical upper limit, which cannot meet the demand for high temporal resolution online monitoring of atmospheric pollen. When faced with sudden fluctuations in pollen concentration, the speed lag of the mechanical platform can also lead to data distortion. Secondly, the proposed scheme lacks adaptability to different detection targets. It primarily targets multi-particle spectral detection of static samples, and its core principle is based on static multi-particle analysis of spectral signals. This requires the sample to be stably supported and in a relatively static state. However, pollen particles in the atmosphere are constantly in a state of irregular dynamic flow, with their spatial position, velocity, and concentration changing rapidly. Existing schemes cannot effectively capture and simultaneously detect particles in such dynamic flow fields, resulting in extremely low applicability in practical atmospheric monitoring scenarios. Furthermore, the scheme cannot accurately count pollen particles moving in the atmosphere. The detection mode is inherently mismatched with the dynamic flow field. Existing technologies are designed for static samples, relying on glass slides for support and detection via a rotating mechanical platform. However, pollen particles in the atmosphere move irregularly with the airflow, and their position, velocity, and concentration change rapidly. The mechanical platform has limited motion inertia, response delay, and positioning accuracy, making it impossible to track the instantaneous position of dynamic particles in real time. This leads to some particles being detected repeatedly or missed, resulting in inaccurate counting. Summary of the Invention

[0006] The purpose of this invention is to solve the technical problems in existing pollen measurement, such as particle overlap, signal interference, inaccurate identification, and large counting deviation, and ultimately to accurately output the number concentration of insect-pollinated pollen.

[0007] To achieve the above objectives, the present invention provides an optical system for measuring microphysical parameters of insect-pollinated pollen based on ultraviolet-induced fluorescence, comprising a 375nm ultraviolet laser source, a collimating lens L1, a silver-plated reflector L2, a focusing lens L3, a short-pass dichroic mirror L4, a fluorescence filter L5, a fluorescence filter L6, an ultraviolet flat beam splitter L7, an aperture L8, a fluorescence detector, a first scattered light detector, and a second scattered light detector; The collimating lens L1, silver-plated reflector L2, focusing lens L3, short-pass dichroic mirror L4, fluorescent filter L6, ultraviolet flat beam splitter L7, aperture L8 and fluorescence detector are sequentially arranged on the laser transmission path of the 375nm ultraviolet laser source and are located on the same laser transmission axis. The collimating lens L1 is arranged parallel to the laser emission end of the 375nm ultraviolet laser source; The silver-plated reflector L2 is set at a laser incident angle of 45°, and the emitted laser from the silver-plated reflector L2 is parallel to the optical axis of the focusing lens L3; the short-pass dichroic mirror L4 and the ultraviolet flat beam splitter L7 are set at a laser incident angle of 45°; the fluorescent filter L6, the aperture L8 and the fluorescence detector are all set parallel to the focusing lens L3 and perpendicular to the optical axis of the focusing lens L3; The optical signal acquisition paths of the first and second scattered light detectors are orthogonal to the laser transmission axis; the first scattered light detector is located on the reflected light path of the short-pass dichroic mirror L4; the fluorescent filter L5 is located on the reflected light path of the short-pass dichroic mirror L4, and is perpendicular to the optical path of the first scattered light detector and adjacent to the first scattered light detector. The second scattered light detector is located on the reflected light path of the ultraviolet flat beam splitter L7; The fluorescence detector is used to receive the fluorescence scattering field strength signal and convert it into a first time-domain electrical pulse signal; the first scattering light detector and the second scattering light detector are used to receive the elastic scattering field strength signal and generate corresponding second and third time-domain electrical pulse signals.

[0008] A method for measuring microphysical parameters of insect-pollinated pollen based on an optical system includes the following steps: S10. Complete the construction of the optical system; S20. Complete the calibration of the optical path and detector; S30. The measuring chamber is positioned, and pollen is blown into the measuring chamber to generate air containing pollen particles for testing. S40, turn on the 375 nm ultraviolet laser light source, irradiate the air to be measured, and simultaneously turn on the fluorescence detector, the first scattered light detector, and the second scattered light detector to realize the collection of the fluorescence scattering field intensity signal and the elastic scattering field intensity signal, and convert them into the first time-domain electric pulse signal, the second time-domain electric pulse signal, and the third time-domain electric pulse signal; S50, pollen particle effectiveness determination and pollen particle number concentration determination.

[0009] Further, the specific process of step S50 is: S51, first re-determination, i.e., specific identification: through the data processing module, analyze the first time-domain electric pulse signal based on the MATLAB program, determine whether there is a characteristic peak of insect-mediated pollen, if the characteristic peak exists, it is a qualified fluorescence waveform signal, and it is determined that the corresponding particle is an insect-mediated pollen particle; otherwise, it is determined as impurities, and the unqualified fluorescence waveform signal is removed; S52, second re-determination, i.e., signal homology identification: determine whether the starting time and the peak time of the first time-domain electric pulse signal, the second time-domain electric pulse signal, and the third time-domain electric pulse signal are consistent, if the time difference is within the threshold value 0.1 us, it is confirmed that the first time-domain electric pulse signal, the second time-domain electric pulse signal, and the third time-domain electric pulse signal come from the same pollen particle; if the time difference exceeds the threshold value 0.1 us, it is determined as an interference signal, and the first time-domain electric pulse signal is removed; S53, third re-determination, i.e., particle position effectiveness identification: the second time-domain electric pulse signal and the third time-domain electric pulse signal are divided into Signal signals and Qualifying signals according to the strength, and the strength of the Signal signals and the Qualifying signals are determined to ensure that the pollen particle is not out of focus, and the specific determination standard is as follows: The strength of the Signal signal < the strength of the Qualifying signal, so as to determine that the particle is in the effective detection range of the light path, further confirm that the particle does not deviate from the focal plane, and ensure the accuracy of signal collection; If the standard is met, the signal is determined to be effective; if the standard is not met, it indicates that the particle deviates from the focal plane or the signal is interfered, the signal is invalid, and the group of signals is removed.

[0010] Further, the measurement cavity is provided by a pollen blowing device, and the pollen blowing device is composed of a pollen storage tank and a measurement cavity forming portion; an annular through hole penetrating through the shell in the thickness direction of the shell is formed on the shell of the measurement cavity forming portion, and protective glasses are arranged at the two ends of the axial direction of the annular through hole to form the measurement cavity. The pollen storage tank is fixed on an outer wall of the shell, and a jet nozzle of the pollen storage tank extends to one side of the measuring cavity; the other side of the shell opposite to the one side is fixed with a hollow needle extending from the inner side of the measuring cavity to the outside of the shell and fixedly connected with an air pipe; the line connecting the jet nozzle and the hollow needle is perpendicular to the central axis of the annular perforation and passes the center of the annular cross section of the annular perforation; the jet nozzle and the hollow needle are symmetrical about the center of the annular cross section; the outer side of the pollen storage tank away from the measuring cavity forming part is fixedly connected with an air valve.

[0011] The beneficial effects of the present application are as follows: 1. Strong specificity in identifying insect-pollinated pollen, solving the problem of impurity interference. By utilizing the ultraviolet-induced fluorescence specificity of substances such as flavonoids and tryptophan in insect-pollinated pollen, and using 375nm ultraviolet laser excitation and 410-490nm characteristic fluorescence signal recognition, only insect-pollinated pollen produces effective fluorescence response, and non-biological particles do not have this signal, achieving accurate differentiation between "insect-pollinated pollen / other particles", completely solving the problem of rough classification and large impurity interference in the prior art, greatly improving the accuracy of detection results, and avoiding the pollen counting deviation caused by non-target particles.

[0012] 2. Adapt to the large particle size characteristics of insect-pollinated pollen, and achieve effective detection of all particle sizes: design a fluorescence light path and light scattering light path system to adapt to insect-pollinated pollen with a particle size of 50μm or more, even more than 100μm, and achieve detection of all particle sizes of insect-pollinated pollen. Solving the problem that the existing laser scattering system only adapts to small particle size aerosols and cannot detect large particle size insect-pollinated pollen, achieving full particle size coverage detection of insect-pollinated pollen, and meeting the needs of different particle sizes of crop insect-pollinated pollen.

[0013] 3. Strong anti-interference ability, high effectiveness and stability of detection data: by comparing the presence or absence of fluorescence signals, the peak time of scattered light signals, signal intensity, and the consistency of multiple signal starting times, interference signals such as defocusing, stray light, and particle superposition are removed, and only effective insect-pollinated pollen signals are retained. The anti-interference ability of the system is greatly improved, avoiding detection errors caused by external environment and equipment itself, ensuring the effectiveness and stability of the detection data, and still achieving accurate detection in complex atmospheric environments.

[0014] 4. High detection efficiency, adapting to large-scale and high-frequency agricultural monitoring needs: after completing the setup of the system and the setting and startup of each detector, the whole process is automatically operated without the need for manual identification and counting, and can achieve efficient detection of low-concentration insect-pollinated pollen in the atmosphere, while supporting 24-hour continuous observation. Solving the problem of low efficiency and strong subjectivity of traditional microscopy, the detection efficiency is improved by more than 100 times, which can meet the high-frequency and continuous monitoring needs of large-scale farmland and different crops in the flowering period, and adapt to the production guidance requirements of modern precision and large-scale agriculture.

[0015] The application will be described in detail below with reference to the accompanying drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 It is an ultraviolet-induced fluorescence-based insect-mediated pollen microphysical parameter measurement optical system.

[0017] Figure 2 It is a schematic diagram of the whole process of insect-mediated pollen number concentration measurement.

[0018] Figure 3 It is a schematic block diagram of pollen particle effectiveness determination and pollen particle number concentration determination.

[0019] Figure 4 It is a schematic diagram of a pollen blowing device.

[0020] Figure 5 It is a schematic diagram of a three-dimensional view of a pollen blowing device.

[0021] Figure 6 It is a schematic diagram of the waveforms of the scattering signal and the fluorescence signal.

[0022] BRIEF DESCRIPTION OF DRAWINGS: 1, 375nm ultraviolet laser light source (375nm ultraviolet laser); 2, fluorescence detector; 3, first scattered light detector; 4, second scattered light detector; 5, pollen storage tank; 6, measurement cavity forming part; 60, housing; 61, annular through hole; 62, hollow needle; 63, air pipe; 7, air valve (gas valve); 8, protective glass. DETAILED DESCRIPTION

[0023] The application will be further described below in conjunction with the embodiments, but those skilled in the art will understand that the following examples are only for illustration of the application and should not be regarded as limiting the scope of the application.

[0024] In order to solve the technical pain points such as particle overlap, signal interference, inaccurate recognition, and large counting deviation in existing pollen measurement, and to achieve the purpose of finally accurately outputting the number concentration of insect-mediated pollen, the experimental device needs to be built and debugged before pollen particle measurement. In the absence of insect-mediated pollen samples, no signal is generated, thereby excluding the influence of external environment or sample residues, and ensuring that the optical path is in the best detection state. Then the insect-mediated pollen sample is sent into the sampling area in a dispersed state to avoid particle interference. Subsequently, the fluorescence signal (fluorescence scattering field intensity signal) and the scattering light signal (elastic scattering field intensity signal) generated by the pollen excitation are synchronously collected through the coaxial orthogonal light path. Finally, the effective pollen particles are screened through multi-dimensional signal cooperative determination, and the pollen number concentration is calculated and output.

[0025] Based on the foregoing design logic, the present embodiment provides a kind of Figure 1The ultraviolet-induced fluorescence-based insect pollination pollen microphysical parameter measurement optical system shown, characterized by comprising a 375nm ultraviolet laser light source 1, a collimating lens L1, a silver-coated mirror L2, a focusing lens L3, a short-wave-pass dichroic mirror L4, a fluorescence filter L5, a fluorescence filter L6, a UV flat beam splitter L7, a diaphragm L8, a fluorescence detector 2, a first scattered light detector 3, and a second scattered light detector 4; wherein the collimating lens L1, the silver-coated mirror L2, the focusing lens L3, the short-wave-pass dichroic mirror L4, the fluorescence filter L6, the UV flat beam splitter L7, the diaphragm L8, and the fluorescence detector 2 are sequentially arranged on the laser transmission path of the 375nm ultraviolet laser light source 1 and are on the same laser transmission axis; and the collimating lens L1 is arranged in parallel with the laser exit end of the 375nm ultraviolet laser light source 1; the silver-coated mirror L2 is arranged at an angle of 45° according to the laser incidence angle, and the exit laser of the silver-coated mirror L2 is parallel to the optical axis of the focusing lens L3; the short-wave-pass dichroic mirror L4 and the UV flat beam splitter L7 are arranged at an angle of 45° according to the laser incidence angle; the fluorescence filter L6, the diaphragm L8, and the fluorescence detector 2 are all arranged in parallel to the focusing lens L3 and are perpendicular to the optical axis of the focusing lens L3; the light signal collection paths of the first scattered light detector 3 and the second scattered light detector 4 are orthogonal to the laser transmission axis; the first scattered light detector 3 is located on the reflected light path of the short-wave-pass dichroic mirror L4; the fluorescence filter L5 is located on the reflected light path of the short-wave-pass dichroic mirror L4 and is arranged adjacent to the first scattered light detector 3 and perpendicular to the light path of the first scattered light detector 3; the second scattered light detector 4 is located on the reflected light path of the UV flat beam splitter L7; wherein the fluorescence detector 2 is used to receive the fluorescence scattering field intensity signal and convert it into a first time-domain electric pulse signal; and the first scattered light detector 3 and the second scattered light detector 4 are used to receive the elastic scattering field intensity signal and generate corresponding second time-domain electric pulse signals and third time-domain electric pulse signals. Finally, the data processing module is used to process the three signals, i.e. the first time-domain electric pulse signal, the second time-domain electric pulse signal, and the third time-domain electric pulse signal, to determine the number or concentration of pollen particles.

[0026] When the optical system is used to measure the microphysical parameters of insect pollination pollen, the following steps need to be performed: S10, the optical system is built, and the required components or optical assemblies include a 375nm ultraviolet laser light source; the optical assemblies are described as follows: L1 collimating lens: lens φ18(f40) rear intercept 36.7 quartz glass, coated with antireflection film, T>95% in the range of 350nm-500nm; L2 silver-coated mirror: reflector-1(24x17x2) coated with reflective film (incident angle 45°, R>95% in the range of 350nm-500nm); L3 focusing lens: lens φ18 (f80) after intercept 76.3 quartz glass coating antireflection film 350nm-500nm, T>95%; L4 short wave pass dichroic mirror: short wave pass dichroic mirror (20x15x1) transmits 350-380nm; Reflect 410-650nm, incident angle 45 degrees; Transmittance >80%, reflectivity >95%; L5 fluorescent filter 1 (410-490nm) transmittance >85%, cutoff depth OD4, extended cutoff region 200-1100nm; Center wavelength: 450nm; Half bandwidth 80±6nm; L6 fluorescent filter 2 (361~389nm) center wavelength 375nm, bandwidth 28nm; Transmittance 90%; Cutoff depth OD6; Cutoff range 200~900nm; L7 ultraviolet flat spectrometer 6x4x1, center wavelength 375nm, 45 degree incidence, spectral ratio T:R=7:3.

[0027] In addition, the fluorescence detector 2, the first scattered light detector 3 and the second scattered light detector 4 need to be prepared.

[0028] After that, assemble and fix according to the preset optical path design on the experimental platform to form a closed detection light path and complete the construction of the insect-mediated pollen microphysical parameter measurement optical system based on ultraviolet-induced fluorescence.

[0029] The assembly or construction needs attention: 1, 375nm ultraviolet laser light source, each detector is a conventional component, simple assembly; 2, the relative position of each lens and dichroic mirror needs to be fixed accurately to ensure that the laser transmission path and the signal acquisition path are coaxial and orthogonal. The specific fixing method is: each optical component is connected with the experimental platform by a bracket and a bolt, the height and angle of the bracket are adjusted, so that the output end of the 375nm ultraviolet laser light source, the L1 collimating lens, the L2 mirror, the L3 focusing lens, the L4 dichroic mirror and the center of the sampling area are on the same laser transmission line.

[0030] 3, the fluorescence detector and the two scattered light detectors are installed in the orthogonal direction of the sampling area, and the receiving end of each detector is aligned with the center of the sampling area to ensure that there is no dead angle for signal acquisition.

[0031] Will Figure 4The pollen spraying device is fixed on the sampling area, the spray hole 50 (i.e. the air jet nozzle) is aligned with the center of the sampling area, and the sampling area is kept at a distance of 5 mm, the measuring cavity of the pollen spraying device (enclosed by the annular perforation 61 and the protective glass 8 at the two axial ends) is provided with the protective glass 8, which ensures the relative sealing of the pollen spraying device without affecting the laser, and the diameter of the spray hole 50 and the diameter of the hollow needle 62 are designed (such as the diameter of the spray hole: 1 mm, the diameter of the hollow needle: 3 mm, the diameter of the air pipe 63: 6 mm, the distance between the spray hole and the hollow needle: 11 mm, etc.), which can make the pollen particles dispersed under the action of the airflow but roughly consistent in direction, and can simulate the situation that the pollen particles enter the sampling area from different positions and different angles in the natural environment. Thus the assembly and construction of the optical system are completed.

[0032] The calibration of the optical path and the detector is completed by performing step S20, and the specific calibration process is as follows: 1. Turn on the ultraviolet laser light source, the fluorescence detector and the two-way scattered light detector, and preheat to a stable working state to avoid signal fluctuations caused by insufficient preheating of the equipment. The preheating time is usually about one minute. Insufficient preheating will cause additional signal interference and affect normal data. After sufficient preheating, the air jet device is not started, and the system has no signal output, then the preheating is sufficient. 2. Calibrate the baseline of the fluorescence detector and the two-way scattered light detector, and deduct the dark noise, i.e. the extremely small signal generated by current, static electricity, light or other external factors. Place the device in an insulating environment, turn off the external light, and the scattered light signal and fluorescence signal peak should not exceed 5 mv when there is no pollen particle blowing, then set a unified signal acquisition baseline to ensure consistent acquisition reference of each detector.

[0033] Before measurement, pollen samples need to be prepared in advance, and the specific process is as follows: 1. Put the insect-pollinated pollen sample into the pollen spraying device: the collection of pollen sample is mainly to scrape the pollen directly from the growing plants and to collect anthers for pollen stripping. The collected anthers or pollen are stored in a 1.5 cm x 1.5 cm x 0.5 cm sample box, dried in a vacuum drying box at 27℃ for 24 hours, and then lightly crushed and treated. The relatively pure pollen particles are obtained by screening through a 100 μm mesh screen, and the pollen particles are stored in a -20℃ low-temperature refrigerator.

[0034] During measurement, the prepared pollen is quantitatively loaded into the sealed storage area of the pollen spraying device, and the storage bin cover is closed. Since the pollen storage tank is tightly connected with the air jet device, it is already sealed except for the air flow port, and will not leak. Moreover, compressed nitrogen gas is used for air jet, which almost contains no water, preventing the pollen from leaking or getting wet. 2. Open the air jet device (such as a compressed nitrogen tank), and control the air flow rate through the air jet device flow regulating valve, and stabilize the flow rate at 0.5-1 m / s. The flow rate range can be fine-tuned according to the size of the pollen grain. The type of pollen used in the experiment is known, and the size range of the pollen grain can be obtained by consulting the literature. The nitrogen total valve is fine-tuned according to the size of the pollen grain to control the maximum flow rate. The core purpose is to make the pollen particles in a dispersed state under the action of the air flow, avoid particle agglomeration and overlap, and at the same time ensure that the particles pass through the sampling area at a uniform speed, and avoid signal acquisition deviation caused by uneven flow rate; The air jet device sends the dispersed pollen particles into the optical sampling area (i.e. the measurement cavity of the pollen blowing device) through the air jet nozzle at a uniform speed. The sample is continuously fed until the signal acquisition is completed. The air flow state is observed in real time during the feeding process. If air flow fluctuation occurs, the air flow regulating valve is adjusted in time to maintain the preset flow rate, ensuring the accuracy and stability of subsequent signal detection. This is a routine operating specification and does not belong to the improvement content of the present embodiment. It is only described as a matter needing attention and will not be repeated.

[0035] Next, the synchronous acquisition of the fluorescence signal and the scattered light signal: when the pollen particles pass through the sampling area, under the excitation of the ultraviolet laser, the fluorescent substances inside the pollen produce characteristic fluorescence signals (wavelength 400-500 nm), and at the same time the pollen particles produce scattered light signals to the incident laser; the fluorescence signal detector and the two-way scattered light detector start the acquisition work synchronously, and capture the fluorescence signal and the two-way scattered light signal respectively. The photoelectric conversion device, i.e. the APD board, converts the optical signal into an electrical signal (which is a function of the existing detector itself or an acquisition board), and outputs the waveforms of the three signals in real time through an oscilloscope, and synchronously records the starting time, peak time, signal intensity and other key parameters of each signal, providing comprehensive data support for subsequent particle effectiveness determination. The specific operation is to turn on the 375 nm ultraviolet laser light source 1 to irradiate the air to be measured in the measurement cavity, and simultaneously turn on the fluorescence detector 2, the first scattered light detector 3 and the second scattered light detector 4 to realize the acquisition of the fluorescence scattered field intensity signal and the elastic scattered field intensity signal, and convert them into first, second and third time-domain electric pulse signals.

[0036] Finally, the pollen particle effectiveness is determined and the pollen particle number concentration is determined. The specific process is as follows: The first heavy determination, i.e. specific recognition: the first time-domain electric pulse signal is analyzed by the data processing module based on the MATLAB program to determine whether there is a characteristic peak of insect-pollinated pollen. If the characteristic peak exists, it is a qualified fluorescence waveform signal, and the corresponding particle is determined to be an insect-pollinated pollen particle; otherwise, it is determined to be an impurity, and the unqualified fluorescence waveform signal is rejected; The second step is signal homology identification: determining whether the start time and peak time of the first time-domain electrical pulse signal are consistent with those of the second and third time-domain electrical pulse signals. If the time difference is within the threshold of 0.1 μs, it is confirmed that the first, second, and third time-domain electrical pulse signals originate from the same pollen particle; if the time difference exceeds the threshold of 0.1 μs, it is determined to be an interference signal, and the first time-domain electrical pulse signal is discarded. The third step is particle position validity identification: the second and third time-domain electrical pulse signals are divided into signal and qualifying signals according to their strength. The strength of the signal and qualifying signals is used to determine whether the pollen particles are out of focus. The specific criteria are as follows: The intensity of the signal is less than the intensity of the Qualifying signal. This is used to determine that the particle is within the effective detection range of the optical path, further confirming that the particle has not deviated from the focal plane, and ensuring accurate signal acquisition. If the standard is met, the signal is considered valid; if the standard is not met, it indicates that the particles are deviating from the focal plane or that there is interference with the signal, the signal is invalid, and the signal group is discarded.

[0037] Based on the above judgment steps, it can be summarized as follows: The acquired three signal data (i.e., the first time-domain electrical pulse signal, the second time-domain electrical pulse signal, and the third time-domain electrical pulse signal) were reconstructed and plotted using a MATLAB program. Figure 5 The waveform diagram shown indicates the peak value, peak time, start point, and start point time of the three signals. Next, the first step is to determine if the fluorescence signal has a peak value. If there is no peak value, it is considered unqualified and discarded; if there is a peak value, it is considered qualified and proceeds to the next criterion. Then, the peak time and start point time of the three signals are compared one by one. If the difference is outside the threshold (i.e., the time difference exceeds the threshold by 0.1µs), it is considered unqualified; if the difference is within the threshold (the time difference is less than or equal to the threshold by 0.1µs), it is considered qualified and proceeds to the third criterion. Then, the peak values ​​of the two scattered signals are compared: if the intensity of the signal is less than the intensity of the qualifying signal, it is considered unqualified; otherwise, it is considered qualified. Finally, the difference between the peak value and the start point time of the three signals is output and counted, i.e., the number concentration is calculated: the number of effective pollen particles passing through the detection area per unit time is counted, combined with sampling time, sampling flow rate, and sampling space volume, using the formula C = N / (Q×T×V), where C is the number concentration in units of particles / L; N is the total number of effective particles; Q is the sampling flow rate; T is the sampling time; and V is the sampling space volume. The number concentration of insect-pollinated pollen is calculated, and the total number of effective particles, signal parameters, and other data are output simultaneously and stored in the local database for subsequent query and analysis.

[0038] The pollen spraying device mentioned in the foregoing embodiment is shown in a structural schematic diagram as shown in Figure 4 、 5 The pollen spraying device mentioned in the foregoing embodiment is shown in a structural schematic diagram as shown in

[0039] The pollen storage tank 5 is fixed on an outer wall of the shell 60, and the air jet nozzle 50 of the pollen storage tank 5 extends to one side of the measuring cavity; the other side of the shell 60 opposite to the one side is fixed with a hollow needle 62 extending from the inside of the measuring cavity to the outside of the shell 60 and fixedly connected with a gas pipe 63. It should be noted that the hollow needle in the embodiment precisely extends into the measuring area and guides the target gas through the hollow structure to avoid sample distortion caused by gas diffusion. The thin diameter design of the needle head of the hollow needle can reduce the interference to the flow field of the measuring area and ensure that the original state of the experimental environment is not destroyed during the experiment. The gas pipe 63 provides a stable gas passage for the system to ensure the controllability of the experimental process. It ensures the experimental repeatability (i.e. the gas in the measuring cavity flows to the hollow needle direction along the gas flow pressure of the inlet, the measured particles are pushed along the hollow pipe of the hollow needle, the measured particles are pushed along the hollow pipe of the hollow needle, the measured particles are pushed along the hollow pipe of the hollow needle, the measured particles are pushed along the hollow pipe of the hollow needle, the measured particles are pushed along the hollow pipe of the hollow needle, the measured particles are pushed along the hollow pipe of the hollow needle, the measured particles are pushed along the hollow pipe of the hollow needle, the measured particles are pushed along the hollow pipe of the hollow needle, the measured particles are pushed along the hollow pipe of the hollow needle, the measured particles are pushed along the hollow pipe of the hollow needle, the measured particles are pushed along the hollow pipe of the hollow needle, the measured particles are pushed along the hollow pipe of the hollow needle, the measured particles are pushed along the hollow pipe of the hollow needle, the measured particles are pushed along the hollow pipe of the hollow needle, the measured particles are pushed along the hollow pipe of the hollow needle, the measured particles are pushed along the hollow pipe of the hollow needle, the measured particles are pushed along the hollow pipe of the hollow needle, the measured particles are pushed along the hollow pipe of the hollow needle, the measured particles are pushed along the hollow pipe of the hollow needle, the measured particles are pushed along the hollow pipe of the hollow needle, the measured particles are pushed along the hollow pipe of the hollow needle, the measured particles are pushed along the hollow pipe of the hollow needle, the measured particles

[0040] The connecting line of the air jet nozzle 50 and the hollow needle 62 is perpendicular to the central axis of the annular through hole 61 and passes through the center of the cross-sectional annular ring of the annular through hole 61; the air jet nozzle 50 and the hollow needle 62 are symmetrical about the center of the annular ring; and the outer side of the pollen storage tank 5 away from the measuring cavity forming part 6 is fixedly connected with a gas valve 7 for connecting a nitrogen gas storage tank, and the pollen outlet of the pollen storage tank 5 shares a connecting pipe section with the gas valve 7, so that when the gas valve 7 is opened and nitrogen gas enters, the sprayed pollen enters the measuring cavity through the air jet nozzle 50 to generate nitrogen gas containing pollen to be measured.

[0041] The preferred embodiments disclosed above are only used to help explain the present application. The preferred embodiments do not describe all the details and do not limit the present application to the specific embodiments. Obviously, many modifications and changes can be made according to the content of the present application. The present application selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present application, so that those skilled in the art can well understand and utilize the present application.

Claims

1. An optical system for measuring microphysical parameters of insect-pollinated pollen based on ultraviolet-induced fluorescence, characterized in that, It includes a 375nm ultraviolet laser source (1), a collimating lens L1, a silver-plated reflector L2, a focusing lens L3, a short-pass dichroic mirror L4, a fluorescent filter L5, a fluorescent filter L6, an ultraviolet flat beam splitter L7, an aperture L8, a fluorescence detector (2), a first scattered light detector (3), and a second scattered light detector (4); The collimating lens L1, silver-plated reflector L2, focusing lens L3, short-wave pass dichroic mirror L4, fluorescent filter L6, ultraviolet flat beam splitter L7, aperture L8 and fluorescence detector (2) are sequentially arranged on the laser transmission path of the 375nm ultraviolet laser source (1) and are located on the same laser transmission axis. The collimating lens L1 is arranged parallel to the laser emission end of the 375nm ultraviolet laser source (1); The silver-plated reflector L2 is set at a laser incident angle of 45°, and the laser emitted from the silver-plated reflector L2 is parallel to the optical axis of the focusing lens L3. The short-wavelength dichroic mirror L4 and the ultraviolet flat beam splitter L7 are set at a 45° laser incident angle. The fluorescent filter L6, the aperture L8, and the fluorescent detector (2) are all arranged parallel to the focusing lens L3 and perpendicular to the optical axis of the focusing lens L3; The optical signal acquisition paths of the first scattering light detector (3) and the second scattering light detector (4) are orthogonal to the laser transmission axis; The first scattered light detector (3) is located on the reflected light path of the short-pass dichroic mirror L4; The fluorescent filter L5 is located on the reflected light path of the short-wave pass dichroic mirror L4, and is perpendicular to the light path of the first scattered light detector (3) and adjacent to the first scattered light detector (3); The second scattering light detector (4) is located on the reflected light path of the ultraviolet flat beam splitter L7; The fluorescence detector (2) is used to receive the fluorescence scattering field intensity signal and convert it into a first time-domain electrical pulse signal; The first scattering light detector (3) and the second scattering light detector (4) are used to receive the elastic scattering field strength signal and generate the corresponding second time-domain electrical pulse signal and third time-domain electrical pulse signal.

2. A method for measuring the microphysical parameters of insect-pollinated pollen based on the optical system described in claim 1, characterized in that, Includes the following steps: S10. Complete the construction of the optical system; S20. Complete the calibration of the optical path and detector; S30. The measuring chamber is positioned, and pollen is blown into the measuring chamber to generate air containing pollen particles for testing. S40. Turn on the 375nm ultraviolet laser source (1) to irradiate the air to be tested, and simultaneously turn on the fluorescence detector (2), the first scattering light detector (3) and the second scattering light detector (4) to collect the fluorescence scattering field strength signal and the elastic scattering field strength signal, and convert them into the first time domain electrical pulse signal, the second time domain electrical pulse signal and the third time domain electrical pulse signal. S50. Determine the effectiveness of pollen particles and determine the pollen particle number concentration.

3. The measurement method according to claim 2, characterized in that, The specific process of step S50 is as follows: S51. First-level judgment, i.e. specific identification: The first time-domain electrical pulse signal is analyzed by the data processing module based on the MATLAB program to determine whether there is a characteristic peak of insect pollen. If the characteristic peak is present, it is a qualified fluorescent waveform signal and the corresponding particle is determined to be an insect pollen particle; otherwise, it is determined to be an impurity and the unqualified fluorescent waveform signal is removed. S52. The second determination, namely signal homology identification, is to determine whether the start time and peak time of the first time-domain electrical pulse signal are consistent with those of the second and third time-domain electrical pulse signals. If the time difference is within the threshold of 0.1 μs, it is confirmed that the first, second, and third time-domain electrical pulse signals come from the same pollen particle. If the time difference exceeds the threshold of 0.1 μs, it is determined to be an interference signal, and the first time-domain electrical pulse signal is discarded. S53. The third level of judgment, namely particle position validity identification: The second and third time-domain electrical pulse signals are divided into signal signals and qualifying signals according to their strength. The determination is made by judging the strength of the signal and qualifying signals to ensure that the pollen particles do not go out of focus. The specific judgment criteria are as follows: The intensity of the signal is less than the intensity of the Qualifying signal. This is used to determine that the particle is within the effective detection range of the optical path, further confirming that the particle has not deviated from the focal plane, and ensuring accurate signal acquisition. If the standard is met, the signal is considered valid; if the standard is not met, it indicates that the particles are deviating from the focal plane or that there is interference with the signal, the signal is invalid, and the signal group is discarded.

4. The measurement method according to claim 2, characterized in that, The measuring chamber is provided by a pollen spraying device, which consists of a pollen storage tank (5) and a measuring chamber forming part (6); An annular perforation (61) is provided on the housing (60) of the measuring cavity forming part (6) along its thickness direction, and protective glass is provided at both ends of the annular perforation (61) to form the measuring cavity shown. The pollen storage tank (5) is fixed to an outer wall of the housing (60), and the nozzle (50) of the pollen storage tank (5) extends into one side of the measuring chamber; a hollow needle (62) is fixed to the other side of the housing (60) opposite to this side, extending from the inside of the measuring chamber to the outside of the housing (60), and is fixedly connected to a duct (63); The line connecting the jet nozzle (50) and the hollow needle (62) is perpendicular to the central axis of the annular perforation (61) and passes through the center of the annular cross-section of the annular perforation (61); the jet nozzle (50) and the hollow needle (62) are symmetrical about the center of the annular circle. A gas valve (7) is fixedly connected to the outside of the pollen storage tank (5) away from the measuring chamber forming part (6).

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