A wheat rust fungicide field efficacy quantitative detection system and method

Abstract

The present application relates to the technical field of pesticide residue and pathogenic bacteria activity detection, and discloses a wheat rust fungicide field efficacy quantitative detection system and method, which comprises: a time division high frequency pulse excitation module for alternately emitting ultraviolet and blue light pulses; a coaxial light collection module provided in front of a coaxial light splitting sub-module and containing a quarter wave plate component to eliminate polarization; a coherent photoelectric detection module for stripping sunlight background and polarization flicker noise by using a double photoelectric sensor and a differential amplification circuit; and a physicochemical parameter inversion calculation module based on the relationship between nanosecond level decay response and photochemical induction kinetics, for calculating the fungicide residue mass concentration and the fungal cell membrane damage degree. The present application eliminates the phase shift distortion caused by the polarization flicker of field wind, and realizes coaxial nondestructive quantitative analysis of chemical residues and biological toxicity under strong sunlight.

Description

Technical Field

[0001] This invention relates to a field efficacy quantitative detection system and method for a fungicide for wheat rust, belonging to the technical field of pesticide residue and pathogen activity detection. Background Technology

[0002] In large-scale wheat disease control and efficacy evaluation, excitation fluorescence and reflectance spectroscopy are commonly used to detect the physical and chemical responses of wheat leaves to determine the plant's physiological state and fungicide residues. During detection, light of a specific wavelength is used to illuminate the leaf to induce the fluorescence absorption response of fungicide molecules, as well as the photochemical response of pathogen cell membranes and chlorophyll, thereby obtaining data related to fungicide residues and fungal infection activity. Existing optical detection systems are usually designed based on two ideal conditions: the surface of the leaf to be tested conforms to the Lambert diffuse reflectance law, and the environmental radiation is uniformly distributed. However, in actual field environments, strong sunlight and natural wind can cause significant interference to the detection. Wheat flag leaves continuously shake and deflect under the action of wind, causing sunlight to form unevenly distributed specularly polarized light on the leaf surface and producing flicker. This directional polarized light will cause different degrees of phase delay and amplitude changes in the signals in different acquisition channels, resulting in a mismatch between the phase and amplitude required for dual-channel background subtraction. This leads to the inability to accurately subtract sunlight noise at the signal acquisition front end, resulting in baseline distortion.

[0003] Besides the limitations of optical acquisition hardware due to the physical movement of the leaves, the signal control and background subtraction methods also have shortcomings. For example, Chinese invention patent application CN1773257A discloses a laser-induced fluorescence telemetry method for water pollution. By controlling a high-voltage pulse-gated photomultiplier tube, it sequentially turns on to receive fluorescence and background light signals within a microsecond time interval, and uses time-gated current integration to complete background subtraction. However, this type of control scheme based on sequential sampling of time-gated signals is based on the premise that the environmental background radiation is stable in the short term. It is only applicable to static or slowly changing water bodies. In complex field scenarios where wind-induced high-frequency shaking of wheat flag leaves occurs, specular reflection polarization scintillation exhibits non-stationary dynamic drift within the microsecond time domain, resulting in a severe disconnect between the phase and amplitude of the background light obtained by the two sequential gating operations. This makes it impossible to effectively cancel background noise, and the scheme cannot decouple the dual parameters of chemical residues and biological toxicity.

[0004] Therefore, the technical problem to be solved by this invention is to eliminate the specular reflection polarization interference caused by natural sunlight background and wind-induced leaf shaking, accurately extract nanosecond-level fluorescence lifetime decay and photochemical response parameters while maintaining the natural physiological state of the leaves and the state of the frost on the surface, and realize coaxial quantitative testing of fungicide chemical residues and pathogen biological damage. Summary of the Invention

[0005] To address the problems in the background art, the technical solution of the present invention is as follows: A field efficacy quantitative detection system for wheat rust fungicides, comprising: The time-division high-frequency pulse excitation module is used to alternately emit the first wavelength pulse light that induces the intrinsic fluorescence of fungicides and pathogens, and the second wavelength pulse light that induces the photochemical response of leaf chlorophyll. The coaxial light acquisition module includes a polarization extinction balancing submodule, a coaxial beam splitting submodule, a first spectral channel module, and a second spectral channel module. The polarization extinction balancing submodule includes a quarter-wave plate assembly set in the front-end optical path of the coaxial beam splitting submodule, which is used to convert the dynamically reflected polarized light from wheat leaves into orthogonal polarization states. The coaxial beam splitting module is used to decompose the acquired beam into a first beam and a second beam. The first spectral channel module is equipped with a target fluorescence bandpass filter, and the second spectral channel module is equipped with a full-spectrum compensation filter. The coherent photoelectric detection module includes a first photoelectric sensing submodule and a second photoelectric sensing submodule connected to a first spectral channel module and a second spectral channel module, respectively, and a differential amplifier circuit module whose input terminals are connected to the first photoelectric sensing submodule and the second photoelectric sensing submodule, respectively. The first photoelectric sensing submodule and the second photoelectric sensing submodule output a first electrical signal and a second electrical signal, respectively. The differential amplifier circuit module is used to perform physical differential subtraction on the first electrical signal and the second electrical signal to remove ambient sunlight background and polarization flicker noise. The physicochemical parameter inversion and solution module is connected to the coherent photoelectric detection module to receive the differentially amplified signal. Based on the nanosecond-level decay response and photochemical induced kinetics, it calculates the residual mass concentration of fungicide and the degree of fungal cell membrane damage.

[0006] Preferably, the first wavelength pulse light emitted by the time-division high-frequency pulse excitation module is ultraviolet pulse light with a center wavelength of 300nm to 350nm and a linewidth of 2nm to 6nm, used to induce intrinsic fluorescence of fungicide active molecules and ergosterol in pathogens; the second wavelength pulse light emitted by the time-division high-frequency pulse excitation module is blue light pulse with a center wavelength of 400nm to 550nm and a linewidth of 2nm to 7nm, used to induce fast photochemical fluorescence induced kinetic response of wheat leaf chlorophyll; the target fluorescence bandpass filter set in the first spectral channel module has a center wavelength of 420nm to 500nm and a bandwidth of 8nm to 12nm, and the full-spectrum compensation filter set in the second spectral channel module covers a transmission band of 400nm to 700nm.

[0007] Preferably, the coaxial light acquisition module also includes a quartz fiber beam guide with a numerical aperture of 0.22 and an objective lens, and the coaxial beam splitting submodule is a 50:50 non-polarized beam splitting cube; the quarter-wave plate assembly adjusts the reflected polarized light generated by the wind-induced micro-shaking of the wheat leaf surface to a phase-orthogonal state, so that the background light noise entering the first photoelectric sensing submodule and the second photoelectric sensing submodule remains synchronized in amplitude and phase.

[0008] Preferably, the system also includes an ambient temperature sensing module, and the physicochemical parameter inversion and calculation module is signal-connected to the ambient temperature sensing module; the physicochemical parameter inversion and calculation module establishes a logarithmic mapping relationship between the measured intensity of the fungicide-specific emission peak and the reference intensity of the leaf reflection, and based on the temperature difference between the measured ambient temperature value collected in real time by the ambient temperature sensing module and the standard reference temperature of 25℃, it performs linear temperature correction on the logarithmic ratio of the measured intensity of the fungicide-specific emission peak and the reference intensity of the leaf reflection through a preset temperature compensation coefficient, so as to calculate the residual mass concentration of the fungicide.

[0009] Preferably, the physicochemical parameter inversion and solution module establishes a nonlinear coupling relationship between the change in the average lifetime of fluorescence and the maximum photochemical quantum yield of chlorophyll, and solves the degree of fungal cell membrane damage; wherein the maximum photochemical quantum yield of chlorophyll is calculated by the physicochemical parameter inversion and solution module based on the initial fluorescence and maximum fluorescence collected under the excitation of the second wavelength pulse light, and the degree of fungal cell membrane damage reflects the synergistic effect of the physical relaxation change caused by the rupture of fungal cell membrane and the plant photochemical toxic response.

[0010] Preferably, both the first and second photoelectric sensing submodules are silicon photomultiplier tubes, and their output terminals are directly connected to the positive and negative input terminals of a differential amplifier circuit module with a bandwidth of not less than 200MHz. The coherent photodetector module also includes a high-speed analog-to-digital converter circuit connected to the output terminal of the differential amplifier circuit module and a 100kHz phase-locked demodulation circuit synchronized with the time-division high-frequency pulse excitation module. The sampling rate of the high-speed analog-to-digital converter circuit is 0.5GS / s to 1.5GS / s, which is used to perform digital high-frequency sampling on the differentially amplified electrical signal and extract the nanosecond-level attenuation signal.

[0011] Preferably, the time-division high-frequency pulse excitation module includes an ultraviolet semiconductor laser and a blue semiconductor laser. The ultraviolet semiconductor laser has a pulse full width at half maximum (FWHM) of 1.5 ns to 3.5 ns and a repetition rate of 80 kHz to 130 kHz, used to generate a first wavelength pulsed light; the blue semiconductor laser has a pulse FWHM of 2 ns to 6 ns, used to generate a second wavelength pulsed light. The time-division high-frequency pulse excitation module also includes a drive control circuit, which drives the ultraviolet semiconductor laser to emit pulse trains with a single pulse duration of 9 ns to 13 ns and a repetition period of 8 μs to 13 μs, and drives the blue semiconductor laser to emit light with an intensity of 2500 μmol·m⁻¹. -2 ·s -1 Up to 3500 μmol·m -2 ·s -1 Furthermore, it consists of continuous saturation pulses with a pulse width ranging from 80ms to 120ms.

[0012] Preferably, the system includes a portable sensor probe module and a signal processing box. The portable sensor probe module has a built-in coaxial light acquisition module and a time-division high-frequency pulse excitation module. The front end of the portable sensor probe module is placed above the surface of the wheat flag leaf to be tested and maintains a non-contact measurement distance of 15mm. The front end of the portable sensor probe module also includes a distance sensing component, which is used to monitor the relative position between the portable sensor probe module and the surface of the wheat flag leaf to be tested, so as to avoid physical contact that would damage the distribution of pesticide residue and physiological activity on the surface of the wheat leaf.

[0013] Preferably, the system also includes a display output module, and the physicochemical parameter inversion and calculation module is connected to the display output module; the physicochemical parameter inversion and calculation module has pre-calibrated benchmark parameters built in, and generates a drug efficacy supplement spraying warning signal when the calculated fungicide residue mass concentration is higher or lower than a preset safety threshold and the fungal cell membrane damage degree is lower than a preset inactivation threshold; the display output module is used to display the fungicide residue mass concentration, fungal cell membrane damage degree and drug efficacy supplement spraying warning signal in real time.

[0014] A method for quantitative field efficacy detection of wheat rust fungicides, used to implement a system for quantitative field efficacy detection of wheat rust fungicides, comprising: Step S101: The time-division high-frequency pulse excitation module alternately emits a first wavelength pulse light that induces the intrinsic fluorescence of the fungicide and the pathogen, and a second wavelength pulse light that induces the photochemical response of leaf chlorophyll. Step S102: The beam of light radiated from the surface of wheat leaves is collected by the coaxial light acquisition module. The quarter-wave plate component in the polarization extinction balance submodule converts the dynamically reflected polarized light from the cuticle of the wheat leaf epidermis into an orthogonal polarization state. The beam is then decomposed into a first beam and a second beam by the coaxial beam splitting submodule, and directed to the first spectral channel module and the second spectral channel module, respectively. Step S103: The first photoelectric sensing submodule and the second photoelectric sensing submodule in the coherent photoelectric detection module receive the first beam and the second beam respectively and output the first electrical signal and the second electrical signal. The differential amplifier circuit module performs physical differential subtraction on the first electrical signal and the second electrical signal to remove the ambient sunlight background and polarization flicker noise. Step S104: Receive the differentially amplified signal through the physicochemical parameter inversion solution module, and calculate the residual mass concentration of the fungicide and the degree of fungal cell membrane damage based on the nanosecond-level decay response and photochemical induced kinetics.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. In the quantitative field efficacy detection of fungicides for wheat rust, the polarization extinction balance submodule and the dual-channel coaxial beam splitter structure are used to process the polarized light reflected from the leaves. This reduces the phase delay and amplitude difference between channels caused by wind-induced leaf shaking, and keeps the background noise of sunlight received by the two photoelectric sensors consistent. Thus, the limitation of field detection by the ideal Lambertian diffuse reflection assumption is overcome, the interference of specular reflection polarization flicker on weak fluorescence signals is reduced, and the waveform integrity and stability of the signals collected under strong natural light are improved.

[0016] 2. By subtracting the sunlight background and polarization flicker noise that coexist in the two signals at the signal acquisition front end through the differential amplifier circuit module, the strong background light can be used to avoid overloading the analog-to-digital conversion circuit and reduce the loss of details of weak fluorescence signals. Combined with phase-locked demodulation synchronized with pulse excitation, the nanosecond-level attenuation response can be extracted more completely, reducing the impact of phase shift and amplitude distortion on the attenuation waveform, and providing a less interfered original signal for subsequent physical parameter inversion and solution.

[0017] 3. By alternately emitting ultraviolet pulse light and blue pulse light, the intrinsic fluorescence information of fungicides and pathogens, as well as the photochemical response information of chlorophyll, can be obtained respectively. Under the same coaxial optical acquisition path, the interference caused by the overlap between the chemical degradation response of fungicides and the damage response of fungal cell membranes can be reduced. Thus, the residual mass concentration of fungicides and the degree of damage to fungal cell membranes can be quantitatively detected at the same time, so that a single field test can take into account both the evaluation of chemical residues and biotoxicity. Attached Figure Description

[0018] Figure 1 This is a flowchart of the operation steps of the detection method of the present invention; Figure 2 This is a topological architecture diagram of the functional modules of the detection system of the present invention.

[0019] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0020] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0021] A field efficacy quantitative detection system for wheat rust fungicide, comprising: The time-division high-frequency pulse excitation module is used to alternately emit the first wavelength pulse light that induces the intrinsic fluorescence of fungicides and pathogens, and the second wavelength pulse light that induces the photochemical response of leaf chlorophyll. The coaxial light acquisition module includes a polarization extinction balancing submodule, a coaxial beam splitting submodule, a first spectral channel module, and a second spectral channel module. The polarization extinction balancing submodule includes a quarter-wave plate assembly set in the front-end optical path of the coaxial beam splitting submodule, which is used to convert the dynamically reflected polarized light from wheat leaves into orthogonal polarization states. The coaxial beam splitting module is used to decompose the acquired beam into a first beam and a second beam. The first spectral channel module is equipped with a target fluorescence bandpass filter, and the second spectral channel module is equipped with a full-spectrum compensation filter. The coherent photoelectric detection module includes a first photoelectric sensing submodule and a second photoelectric sensing submodule connected to a first spectral channel module and a second spectral channel module, respectively, and a differential amplifier circuit module whose input terminals are connected to the first photoelectric sensing submodule and the second photoelectric sensing submodule, respectively. The first photoelectric sensing submodule and the second photoelectric sensing submodule output a first electrical signal and a second electrical signal, respectively. The differential amplifier circuit module is used to perform physical differential subtraction on the first electrical signal and the second electrical signal to remove ambient sunlight background and polarization flicker noise. The physicochemical parameter inversion and solution module is connected to the coherent photoelectric detection module to receive the differentially amplified signal. Based on the nanosecond-level decay response and photochemical induced kinetics, it calculates the residual mass concentration of fungicide and the degree of fungal cell membrane damage.

[0022] Preferably, the first wavelength pulse light emitted by the time-division high-frequency pulse excitation module is ultraviolet pulse light with a center wavelength of 300nm to 350nm and a linewidth of 2nm to 6nm, used to induce intrinsic fluorescence of fungicide active molecules and ergosterol in pathogens; the second wavelength pulse light emitted by the time-division high-frequency pulse excitation module is blue light pulse with a center wavelength of 400nm to 550nm and a linewidth of 2nm to 7nm, used to induce fast photochemical fluorescence induced kinetic response of wheat leaf chlorophyll; the target fluorescence bandpass filter set in the first spectral channel module has a center wavelength of 420nm to 500nm and a bandwidth of 8nm to 12nm, and the full-spectrum compensation filter set in the second spectral channel module covers a transmission band of 400nm to 700nm.

[0023] Preferably, the coaxial light acquisition module also includes a quartz fiber beam guide with a numerical aperture of 0.22 and an objective lens, and the coaxial beam splitting submodule is a 50:50 non-polarized beam splitting cube; the quarter-wave plate assembly adjusts the reflected polarized light generated by the wind-induced micro-shaking of the wheat leaf surface to a phase-orthogonal state, so that the background light noise entering the first photoelectric sensing submodule and the second photoelectric sensing submodule remains synchronized in amplitude and phase.

[0024] Preferably, the system also includes an ambient temperature sensing module, and the physicochemical parameter inversion and calculation module is signal-connected to the ambient temperature sensing module; the physicochemical parameter inversion and calculation module establishes a logarithmic mapping relationship between the measured intensity of the fungicide-specific emission peak and the reference intensity of the leaf reflection, and based on the temperature difference between the measured ambient temperature value collected in real time by the ambient temperature sensing module and the standard reference temperature of 25℃, it performs linear temperature correction on the logarithmic ratio of the measured intensity of the fungicide-specific emission peak and the reference intensity of the leaf reflection through a preset temperature compensation coefficient, so as to calculate the residual mass concentration of the fungicide.

[0025] Preferably, the physicochemical parameter inversion and solution module establishes a nonlinear coupling relationship between the change in the average lifetime of fluorescence and the maximum photochemical quantum yield of chlorophyll, and solves the degree of fungal cell membrane damage; wherein the maximum photochemical quantum yield of chlorophyll is calculated by the physicochemical parameter inversion and solution module based on the initial fluorescence and maximum fluorescence collected under the excitation of the second wavelength pulse light, and the degree of fungal cell membrane damage reflects the synergistic effect of the physical relaxation change caused by the rupture of fungal cell membrane and the plant photochemical toxic response.

[0026] Preferably, both the first and second photoelectric sensing submodules are silicon photomultiplier tubes, and their output terminals are directly connected to the positive and negative input terminals of a differential amplifier circuit module with a bandwidth of not less than 200MHz. The coherent photodetector module also includes a high-speed analog-to-digital converter circuit connected to the output terminal of the differential amplifier circuit module and a 100kHz phase-locked demodulation circuit synchronized with the time-division high-frequency pulse excitation module. The sampling rate of the high-speed analog-to-digital converter circuit is 0.5GS / s to 1.5GS / s, which is used to perform digital high-frequency sampling on the differentially amplified electrical signal and extract the nanosecond-level attenuation signal.

[0027] Preferably, the time-division high-frequency pulse excitation module includes an ultraviolet semiconductor laser and a blue semiconductor laser. The ultraviolet semiconductor laser has a pulse full width at half maximum (FWHM) of 1.5 ns to 3.5 ns and a repetition rate of 80 kHz to 130 kHz, used to generate a first wavelength pulsed light; the blue semiconductor laser has a pulse FWHM of 2 ns to 6 ns, used to generate a second wavelength pulsed light. The time-division high-frequency pulse excitation module also includes a drive control circuit, which drives the ultraviolet semiconductor laser to emit pulse trains with a single pulse duration of 9 ns to 13 ns and a repetition period of 8 μs to 13 μs, and drives the blue semiconductor laser to emit light with an intensity of 2500 μmol·m⁻¹. -2 ·s -1 Up to 3500 μmol·m -2 ·s -1 Furthermore, it consists of continuous saturation pulses with a pulse width ranging from 80ms to 120ms.

[0028] Preferably, the system includes a portable sensor probe module and a signal processing box. The portable sensor probe module has a built-in coaxial light acquisition module and a time-division high-frequency pulse excitation module. The front end of the portable sensor probe module is placed above the surface of the wheat flag leaf to be tested and maintains a non-contact measurement distance of 15mm. The front end of the portable sensor probe module also includes a distance sensing component, which is used to monitor the relative position between the portable sensor probe module and the surface of the wheat flag leaf to be tested, so as to avoid physical contact that would damage the distribution of pesticide residue and physiological activity on the surface of the wheat leaf.

[0029] Preferably, the system also includes a display output module, and the physicochemical parameter inversion and calculation module is connected to the display output module; the physicochemical parameter inversion and calculation module has pre-calibrated benchmark parameters built in, and generates a drug efficacy supplement spraying warning signal when the calculated fungicide residue mass concentration is higher or lower than a preset safety threshold and the fungal cell membrane damage degree is lower than a preset inactivation threshold; the display output module is used to display the fungicide residue mass concentration, fungal cell membrane damage degree and drug efficacy supplement spraying warning signal in real time.

[0030] A method for quantitative field efficacy detection of wheat rust fungicides, used to implement a system for quantitative field efficacy detection of wheat rust fungicides, comprising: Step S101: The time-division high-frequency pulse excitation module alternately emits a first wavelength pulse light that induces the intrinsic fluorescence of the fungicide and the pathogen, and a second wavelength pulse light that induces the photochemical response of leaf chlorophyll. Step S102: The beam of light radiated from the surface of wheat leaves is collected by the coaxial light acquisition module. The quarter-wave plate component in the polarization extinction balance submodule converts the dynamically reflected polarized light from the cuticle of the wheat leaf epidermis into an orthogonal polarization state. The beam is then decomposed into a first beam and a second beam by the coaxial beam splitting submodule, and directed to the first spectral channel module and the second spectral channel module, respectively. Step S103: The first photoelectric sensing submodule and the second photoelectric sensing submodule in the coherent photoelectric detection module receive the first beam and the second beam respectively and output the first electrical signal and the second electrical signal. The differential amplifier circuit module performs physical differential subtraction on the first electrical signal and the second electrical signal to remove the ambient sunlight background and polarization flicker noise. Step S104: Receive the differentially amplified signal through the physicochemical parameter inversion solution module, and calculate the residual mass concentration of the fungicide and the degree of fungal cell membrane damage based on the nanosecond-level decay response and photochemical induced kinetics.

[0031] Example 1: In the current main wheat-producing areas of the Central Plains, the midday sunlight is strong. When the field wind speed reaches 8 m / s, the flag leaves of the wheat under test shake continuously with the wind and deflect at an angle. The strong natural light forms uneven specular reflection polarization scintillation on the surface of the cuticle and wax layer of the flag leaf epidermis, causing asymmetric phase delay and amplitude distortion between the background light received by the first spectral channel module and the second spectral channel module, which does not meet the Lambertian diffuse reflection condition of traditional optical detection. During the detection process, the leaves are kept in a naturally exposed state and are not mechanically clamped. The acquisition baseline drifts with polarization scintillation, which in turn interferes with the extraction of the fungicide specific emission peak and the nanosecond-level decay response corresponding to fungal cell membrane damage.

[0032] The portable sensor probe module maintains a non-contact measurement distance of 15 mm between its front objective lens and the surface of the wheat flag leaf under test. The coaxial light acquisition module uses a quartz fiber beam guide with a numerical aperture of 0.22 to transmit the acquisition beam. The polarization extinction balance submodule is set in the pre-stage optical path of the coaxial beam splitter module. The quarter-wave plate component in it converts the dynamically reflected polarized light from the wheat leaf epidermal cuticle into orthogonal polarization states, specifically, in this embodiment, orthogonal circularly polarized light. The high-contrast polarization extinction plate set after the quarter-wave plate component further weakens the residual anisotropy. The anisotropic polarization component is reduced, and the phase difference it causes is decreased, so that the polarized scintillation light entering the coaxial photonics module no longer has a fixed polarization direction. The coaxial photonics module uses a 50:50 unpolarized beam splitting cube to split the collected beam into a first beam and a second beam. The first beam enters the first photoelectric sensing submodule after passing through a target fluorescence bandpass filter with a center wavelength of 460nm. The second beam enters the second photoelectric sensing submodule after passing through a full-spectrum compensation filter with a transmission band of 400nm to 700nm. Both photoelectric sensing submodules use silicon photomultiplier tubes.

[0033] To compensate for the difference in light energy between the two spectral channels caused by the different transmission bandwidths of the filters, a transmittance attenuator is placed immediately after the full-spectrum compensation filter to reduce the optical transmittance of the second beam to one-thirtieth. Simultaneously, the drive bias voltage of the second photoelectric sensing submodule and the feedback resistor of the pre-amplifier are independently adjusted to ensure that its photoelectric conversion gain is inversely proportional to that of the first photoelectric sensing submodule. By reducing the incident light intensity of the second beam and adjusting the electrical gain proportionally, the static DC level difference and dynamic fluctuation of the two output signals in the absence of fluorescence excitation are measured. The amplitude difference is reduced to within 1mV, keeping the background light noise synchronized in amplitude and phase. The first electrical signal output from the first photoelectric sensing submodule and the second electrical signal output from the second photoelectric sensing submodule are respectively connected to the positive and negative input terminals of the differential amplifier circuit module with a bandwidth of 200MHz. The differential amplifier circuit module performs physical differential subtraction to remove more than 99.8% of the ambient sunlight background and polarization flicker noise in the analog signal pre-stage, avoiding overload saturation of the high-speed analog-to-digital conversion circuit caused by strong background, while retaining the attenuated waveform of the weak fluorescence signal.

[0034] A time-division high-frequency pulse excitation module drives a solid-state ultraviolet semiconductor laser with a center wavelength of 340 nm and a pulse full width at half maximum (FWHM) of 2.5 ns to emit a first wavelength pulse at a repetition frequency of 100 kHz. The 100 kHz phase-locked demodulation circuit in the coherent photodetector module is synchronized with the first wavelength pulse. A high-speed analog-to-digital converter digitally samples the differentially amplified signal at a sampling rate of 1 GS / s, extracting the nanosecond-level decay response without phase shift distortion or waveform distortion. The physicochemical parameter inversion and calculation module calculates the change in average fluorescence lifetime according to the following formula. : ,in, This represents the change in average fluorescence lifetime. For physical differential phase-locked demodulation over time The varying excitation fluorescence intensity, To attenuate the acquisition time, The attenuation acquisition window within a single pulse period is set to 100ns in this embodiment; The baseline fluorescence lifetime of untreated healthy wheat leaves.

[0035] During the interval between the first wavelength pulses, the time-division high-frequency pulse excitation module switches to a blue semiconductor laser with a center wavelength of 450 nm to emit a second wavelength pulse. The full width at half maximum (FWHM) of a single pulse from the blue semiconductor laser is 5 ns. The drive control circuit continuously triggers blue pulses within a 100 ms duration, maintaining the light intensity on the leaf surface at 3000 μmol·m⁻¹. -2 ·s -1This generates continuous saturation pulses, inducing a rapid photochemical fluorescence-induced kinetic response in wheat leaf chlorophyll; the physicochemical parameter inversion and solution module collects the initial fluorescence. and maximum fluorescence Calculate variable fluorescence and the maximum photochemical quantum yield of chlorophyll Simultaneously, it receives ambient temperature measurements from the ambient temperature sensing module. The intensity of the bactericide-specific emission peak obtained under 340nm ultraviolet pulse excitation was measured. and blade reflection reference intensity The residual mass concentration of the fungicide is calculated by solving the following set of nonlinear coupled equations. With fungal cell membrane damage : ,in, This refers to the residual mass concentration of the bactericide. The degree of fungal cell membrane damage. The measured intensity of the bactericide-specific emission peak in the 460 nm band. The reference intensity for blade reflection. This is the measured value of the ambient temperature at the site. For the standard reference temperature, this embodiment is set to 25°C; The preset linear temperature compensation coefficient is set to 0.0035 / ℃. The baseline fluorescence lifetime of untreated healthy wheat leaves. This represents the change in average fluorescence lifetime. The dimensionless maximum photochemical quantum yield of chlorophyll; The proportionality coefficient is obtained by calibration based on standard samples with known residual concentrations of fungicides, and its dimensions are the same as those of standard samples. The mg / kg output is matched; The physicochemical parameter inversion solution module will use the dimensionless proportionality coefficients determined by fitting the average fluorescence lifetime change, maximum photochemical quantum yield of chlorophyll, and fungal cell membrane rupture rate of the standard infected samples. The output is limited to the range of 0% to 100%.

[0036] Within the same measurement area, the nanosecond-level decay response obtained after excitation by the first wavelength pulsed light reflects the ultrafast relaxation of the electronically excited state caused by changes in the microenvironment around the internal fluorophore after fungal cell membrane damage; the millisecond to second-level photochemical response obtained after excitation by the second wavelength pulsed light reflects the physiological changes in the electron transport chain of the photosynthetic system within leaf cells; pathogen infection causes fungal cell membrane rupture and a decrease in the integrity of the host mesophyll cell wall, which occur spatially together. Electrolyte extravasation caused by cell membrane rupture inhibits the photochemical charge separation process in plants. Therefore, the two types of responses at different time scales have a photochemical induction kinetic correlation, which provides a physicochemical parameter inversion and solution module to collaboratively solve the fungicide residual mass concentration and the degree of fungal cell membrane damage, and outputs coaxial quantitative detection results under natural leaf exposure and non-contact measurement conditions.

[0037] Example 2: The current test platform uses a solar simulator and a wind field generator to create a field simulation environment. The radiation intensity of the solar simulator is set to 1000 W / m². 2 The wind generator drives the wheat flag leaves to shake with a continuous wind speed of 8 m / s. The test signal source is superimposed with Gaussian white noise with a signal-to-noise ratio of 20 dB and 50 Hz power frequency harmonics to simulate the detection conditions of strong natural light, blade deflection, and electromagnetic interference. The repetition frequency of the time-division high-frequency pulse excitation module is determined based on the fluorescence attenuation acquisition window and the blade thermal accumulation. When the repetition frequency is too low, the signal-to-noise ratio of the nanosecond-level attenuation response is low under strong background noise. When the repetition frequency is higher than 150 kHz, the continuous pulse energy accumulation will cause local photobleaching and thermal relaxation drift of the blade. Therefore, the repetition frequency is set to 100 kHz to provide a 100 ns attenuation acquisition window. It is located within a single pulse cycle.

[0038] The portable sensor probe module maintains a non-contact measurement distance of 15mm between its front objective lens and the surface of the wheat flag leaf under test. The coaxial light acquisition module uses a quartz fiber beam guide with a numerical aperture of 0.22 to transmit the acquisition beam. The quarter-wave plate component in the polarization extinction balancing submodule converts the dynamically reflected polarized light from the wheat leaf cuticle caused by wind-induced shaking into an orthogonal polarization state. The coaxial beam splitting submodule uses a 50:50 non-polarized beam splitting cube to split the acquisition beam into a first beam and a second beam; the first beam passes through a center wavelength of 460nm. After passing through the target fluorescence bandpass filter, the light is received by the first photoelectric sensing submodule. After passing through the full-spectrum compensation filter with a transmission band of 400nm to 700nm, the second photoelectric sensing submodule is received by the second photoelectric sensing submodule. Both photoelectric sensing submodules use silicon photomultiplier tubes. The two output signals are respectively connected to the positive and negative input terminals of a differential amplifier circuit module with a bandwidth of 200MHz. The differential amplifier circuit module performs physical differential subtraction to remove more than 99.8% of the ambient sunlight background and polarization flicker noise in the analog signal pre-stage.

[0039] A time-division high-frequency pulse excitation module drives a solid-state ultraviolet semiconductor laser with a center wavelength of 340nm and a pulse full width at half maximum (FWHM) of 2.5ns to emit a first wavelength pulse at a repetition frequency of 100kHz. The 100kHz phase-locked demodulation circuit in the coherent photodetector module is synchronized with the first wavelength pulse. A high-speed analog-to-digital converter digitally samples the differentially amplified signal at a sampling rate of 1GS / s, extracting the nanosecond-level attenuation response. The physicochemical parameter inversion and calculation module calculates the change in average fluorescence lifetime according to the following formula. : ,in, This represents the change in average fluorescence lifetime. For physical differential phase-locked demodulation over time The varying excitation fluorescence intensity, To attenuate the acquisition time, The attenuation acquisition window within a single pulse period is set to 100ns in this embodiment; The baseline fluorescence lifetime of untreated healthy wheat leaves.

[0040] During the interval between the emission of the first wavelength pulsed light, the time-division high-frequency pulse excitation module switches to a blue semiconductor laser with a center wavelength of 450 nm and a pulse full width at half maximum (FWHM) of 5 ns. The drive control circuit continuously triggers blue light pulses within 100 ms to maintain the light intensity on the leaf surface at 3000 μmol·m⁻¹. -2 ·s -1 A continuous saturation pulse is generated, inducing a rapid photochemical fluorescence-induced kinetic response in wheat leaf chlorophyll. The physicochemical parameter inversion and solution module collects the initial fluorescence. and maximum fluorescence Calculate variable fluorescence and the maximum photochemical quantum yield of chlorophyll Simultaneously, it receives ambient temperature measurements from the ambient temperature sensing module. The intensity of the bactericide-specific emission peak obtained under 340nm ultraviolet pulse excitation was measured. and blade reflection reference intensity The residual mass concentration of the fungicide is calculated by solving the following set of nonlinear coupled equations. and degree of fungal cell membrane damage : ,in, This refers to the residual mass concentration of the bactericide. The degree of fungal cell membrane damage. The measured intensity of the bactericide-specific emission peak in the 460 nm band. The reference intensity for blade reflection. This is the measured value of the ambient temperature at the site. For the standard reference temperature, this embodiment is set to 25°C; The preset linear temperature compensation coefficient is set to 0.0035 / ℃. The proportionality coefficient is obtained by calibration based on standard samples with known residual concentrations of fungicides, and its dimensions are the same as those of standard samples. The mg / kg output is matched; Based on the dimensionless proportionality coefficients obtained from the standard contaminated samples, the physicochemical parameter inversion solution module will... The output is limited to the range of 0% to 100%.

[0041] When continuously sampling the sample group of this invention, the measured value of the ambient temperature on site one day after the application of the pesticide. The measured intensity of the bactericide-specific emission peak was 22.4℃. The reference intensity for blade reflection is 412.5 mV. The mean fluorescence lifetime change was 95.2 mV. The maximum photochemical quantum yield of chlorophyll is 1.82 ns. The value is 0.78; the physicochemical parameter inversion calculation module obtains the residual mass concentration of the fungicide based on this. The fungal cell membrane damage level was 4.52 mg / kg. The percentage was 82.5%, the actual residue measured by high performance liquid chromatography for the same sample was 4.48 mg / kg, and the fungal cell membrane rupture rate observed by transmission electron microscopy was 83.1%.

[0042] Three days after application, the ambient temperature at the site was measured. The specific emission peak intensity of the bactericide was measured at 25.1℃. The blade reflection reference intensity dropped to 285.4mV. The mean fluorescence lifetime change was 94.8 mV. The maximum photochemical quantum yield of chlorophyll is 1.35 ns. The calculated residual mass concentration of the fungicide is 0.72. The fungal cell membrane damage level was 2.81 mg / kg. The percentage was 68.3%, the actual residue measured by high performance liquid chromatography was 2.85 mg / kg, and the fungal cell membrane rupture rate observed by transmission electron microscopy was 67.8%.

[0043] Five days after application, the ambient temperature at the site was measured. The specific emission peak intensity of the bactericide was measured at 28.0℃. The blade reflection reference intensity is 168.1 mV. The mean fluorescence lifetime change was 96.1 mV. The maximum photochemical quantum yield of chlorophyll is 0.81 ns. The calculated residual mass concentration of the fungicide is 0.65. The degree of fungal cell membrane damage was 1.25 mg / kg. The percentage was 42.1%, the actual residue measured by high performance liquid chromatography was 1.21 mg / kg, and the fungal cell membrane rupture rate observed by transmission electron microscopy was 41.5%.

[0044] Seven days after application, the ambient temperature at the site was measured. The specific emission peak intensity of the bactericide was measured at 24.5℃. The reference intensity of the blade reflection is 82.3mV. The mean fluorescence lifetime change was 95.0 mV. The maximum photochemical quantum yield of chlorophyll is 0.28 ns. The calculated residual mass concentration of the fungicide is 0.51. The degree of fungal cell membrane damage was 0.38 mg / kg. The residual concentration was 15.6%, the actual residue measured by high performance liquid chromatography was 0.40 mg / kg, and the fungal cell membrane rupture rate observed by transmission electron microscopy was 16.0%. Among the above four sampling time points, the relative errors between the calculated values ​​of fungicide residue mass concentration and the actual values ​​measured by high performance liquid chromatography at 1 day, 3 days and 5 days after application were all less than 3.5%. With the extension of application time, the direction of change of fungal cell membrane damage was consistent with the direction of change of fungal cell membrane rupture rate.

[0045] In control group 1, the polarization extinction balance submodule was removed, and the remaining detection conditions were kept consistent with those of the sample group of this invention 3 days after drug application. The ambient temperature was measured at the site. The blade reflection reference intensity is 25.1℃. The maximum photochemical quantum yield of chlorophyll is 94.8 mV. The concentration was 0.72, the actual residue measured by high performance liquid chromatography was 2.85 mg / kg, and the fungal cell membrane rupture rate observed by transmission electron microscopy was 67.8%. Due to the asymmetric phase delay formed between the two spectral channels by wind-induced polarization scintillation, the background noise of the two paths could not be fully canceled in the differential amplifier circuit module, resulting in a decrease in the measured intensity of the fungicide-specific emission peak. The fluorescence mean lifetime changed to 342.1 mV. The concentration of the fungicide residue increased from 1.35 ns to 2.15 ns three days after application. The calculated value became 3.68 mg / kg, and the relative error increased to 29.1%, indicating fungal cell membrane damage. The calculated value becomes 95.2%.

[0046] In control group two, the differential amplifier circuit module was removed, and all other testing conditions remained the same as those used 3 days after application, including the ambient temperature measurement. The blade reflection reference intensity is 25.1℃. The maximum photochemical quantum yield of chlorophyll is 94.8 mV. The concentration was 0.72, the actual residue measured by high performance liquid chromatography was 2.85 mg / kg, and the fungal cell membrane rupture rate observed by transmission electron microscopy was 67.8%. Strong sunlight background directly entered the first photoelectric sensing submodule, increasing the measurement intensity of the fungicide-specific emission peak. The change in mean fluorescence lifetime was increased to 920.5 mV. The residual mass concentration of the bactericide output by the physicochemical parameter inversion solution module becomes 4.82 ns. The fungal cell membrane damage level was 11.45 mg / kg. The result reached 100.0%, which is a significant deviation from the corresponding measured result.

[0047] In the control group exceeding the range, the measured ambient temperature 3 days after application was [value missing]. The temperature rose to 42.5℃, exceeding the preset temperature compensation window's upper limit of 35℃; at this point, the measured intensity of the bactericide's specific emission peak... The reference intensity for blade reflection is 285.4 mV. The mean fluorescence lifetime change was 94.8 mV. The maximum photochemical quantum yield of chlorophyll is 1.35 ns. The degree of fungal cell membrane damage was 0.72. The calculated value was 68.3%, the actual residue measured by high-performance liquid chromatography was 2.85 mg / kg, and the fungal cell membrane rupture rate observed by transmission electron microscopy was 67.8%. The nonlinear thermal quenching of the fungicide molecules caused deviations in linear temperature compensation, resulting in a lower fungicide residue concentration. The calculated value became 3.21 mg / kg, and the calculation error increased to 12.8%. This result indicates that linear temperature compensation is suitable for the working window of 10℃ to 35℃. When the temperature exceeds this range, the calculation deviation of the residual mass concentration of the fungicide increases.

[0048] Example 3: Before field testing, the physicochemical parameter inversion and solution module determines the proportional coefficients through a standardized calibration process. proportionality coefficient Linear temperature compensation coefficient and baseline fluorescence lifetime of untreated healthy wheat leaves Calibration At that time, untreated wheat flag leaves in normal physiological condition were placed in a temperature-controlled dark room at 25°C. A time-division high-frequency pulse excitation module emitted a first-wavelength pulse light with a center wavelength of 340nm. A high-speed analog-to-digital converter sampled the differentially amplified fluorescence attenuation waveform. The physicochemical parameter inversion and calculation module integrated the sampled data to measure... It is 2.15ns.

[0049] Calibration At that time, known standard leaf samples with fungicide residue concentrations ranging from 0.05 mg / kg to 10.0 mg / kg were selected. The front objective lens of the portable sensing probe module was kept at a non-contact measurement distance of 15 mm from the leaf surface, and the intensity of the fungicide-specific emission peak of each standard leaf sample was collected. and blade reflection reference intensity The physical parameter inversion solution module calculates... and The logarithmic ratio was calculated, and this logarithmic ratio was linearly fitted to the known residual mass concentration of the fungicide. The result was used to determine the... .

[0050] Calibration Wheat leaves inoculated with rust fungi and exhibiting different infection activities were selected. The chlorophyll photochemical fluorescence induced kinetic response was induced by a second-wavelength pulsed light to obtain the maximum photochemical quantum yield of chlorophyll. Simultaneously, the change in average fluorescence lifetime was obtained using the first wavelength pulsed light. Then, combined with the rupture of the fungal cell membrane in the corresponding leaf, to and The nonlinear coupling relationship is fitted to determine the... .

[0051] Calibration At that time, standard leaf samples with a fungicide residue concentration of 2.5 mg / kg were placed in a temperature-controlled dark room, and the ambient temperature was gradually changed in 5°C increments within the range of 10°C to 35°C. The results at each temperature node were recorded. and The logarithmic ratio of the two was calculated, and using the logarithmic ratio at 25℃ as the reference, the relative deviation of the logarithmic ratio at other temperature nodes was subjected to least-squares linear fitting with the temperature difference. The slope of the fitted line was used as the... In this embodiment, Fluorulating around 0.0035℃, with a fitting coefficient of determination greater than 0.995, when the ambient temperature is below 10℃, molecular thermal motion is restricted, and the fluorescence quantum yield increases nonlinearly; when the ambient temperature is above 35℃, the bactericide molecules exhibit significant thermal quenching. Therefore, linear temperature compensation is applicable to the temperature range of 10℃ to 35℃.

[0052] During calibration, the non-contact measurement distance between the portable sensing probe module and the surface of the wheat flag leaf was based on 15mm. When this distance fluctuated within the range of 12mm to 18mm, the geometric attenuation of the collected beam caused a proportional and directional amplitude change in the first and second spectral channel modules. After conversion by the first and second photoelectric sensing submodules, this distance attenuation factor was... and The ratios cancel each other out, resulting in a lower residual mass concentration of the fungicide. The solution results remain stable.

[0053] In digital signal processing, the high-speed analog-to-digital converter (ADC) writes the discrete voltage sequence output by the differential amplifier module into a high-speed buffer at a sampling rate of 1 GS / s, with a 100 ns attenuation acquisition window set within a single pulse period. The window contains 100 discrete sampling points. The physicochemical parameter inversion and solution module reads the voltage value of each sampling point and performs numerical integration. Based on the integration result, the change in the average fluorescence lifetime is obtained. .

[0054] To reduce the breakdown voltage drift of silicon photomultiplier tubes and the gain mismatch between the two channels caused by changes in ambient temperature, the ambient temperature sensing module collects real-time measurements of the ambient temperature. The input is then fed into the bias voltage control circuits of the first and second photoelectric sensing submodules. These circuits adjust the drive bias voltage of the silicon photomultiplier tube at a slope of 56mV / ℃ to stabilize the gain of both photoelectric sensing submodules. Simultaneously, the physical and chemical parameter inversion calculation module... Call ,right and The logarithmic ratio was linearly corrected for temperature, and the residual mass concentration of the fungicide was calculated. .

[0055] Degree of fungal cell membrane damage In the solution process, the physicochemical parameter inversion solution module uses the maximum photochemical quantum yield of chlorophyll in healthy wheat leaves (0.83) as a reference benchmark, and calculates the measured... The result was normalized to 0.83, and the photochemical damage inhibition rate was obtained by subtracting the normalized result from 1. (The remaining text appears to be incomplete and contains errors. A more accurate translation would require the full context.) When the value approaches 0.83, the photochemical damage inhibition rate approaches 0; leaf damage worsens and As the value gradually decreases, the photochemical damage inhibition rate increases accordingly, based on the physicochemical parameter inversion solution module. and Nonlinear coupling relationship calculation The direction of change in the solution results is verified using this photochemical damage inhibition rate; when When it approaches 0, The result is limited to 100%, and all other solutions are limited to the range of 0% to 100%. Then... and Output to the display output module.

[0056] Example 4: This example combines Figures 1 to 2 This paper describes a field efficacy quantitative detection system and method for a wheat rust fungicide, such as... Figure 1 As shown, in step S101, the first and second wavelength pulses are alternately emitted by the time-division high-frequency pulse excitation module to induce the intrinsic fluorescence of the fungicide and pathogen, as well as the photochemical induced response of leaf chlorophyll. After executing step S101, the process proceeds to step S102, where the surface radiation beam is collected by the coaxial light acquisition module, converted into an orthogonal polarization state by the polarization extinction balance submodule, and decomposed by the coaxial light splitting submodule and directed to dual-spectral channels. Then, the process proceeds from step S102 to step S103, where the dual beams are received by the coherent photodetector module and an electrical signal is output. The differential amplifier circuit module performs physical differential subtraction to remove the ambient sunlight background and polarization flicker noise. Then, the process proceeds from step S103 to step S104, where the differential signal is received by the physicochemical parameter inversion solution module. Based on the nanosecond-level decay response and photochemical induced kinetics, the residual mass concentration of the fungicide and the degree of fungal cell membrane damage are calculated.

[0057] like Figure 2 As shown, the time-division high-frequency pulse excitation module includes an ultraviolet semiconductor laser and a blue semiconductor laser. The time-division high-frequency pulse excitation module emits first / second wavelength pulsed light towards the wheat flag leaf under test. The physicochemical parameter inversion and calculation module outputs a synchronization signal to the time-division high-frequency pulse excitation module. The coaxial light acquisition module includes a quartz fiber beam guide. The coaxial light acquisition module receives the acquired beam emitted from the wheat flag leaf under test and transmits the reflected polarized light to the polarization extinction balancing submodule. The polarization extinction balancing submodule includes a quarter-wave plate assembly. The polarization extinction balancing submodule transmits orthogonal polarization states to the coaxial beam splitting submodule. The coaxial beam splitting submodule includes 5... The 0:50 non-polarized beam splitting cube, with a coaxial beam splitting module transmitting the first and second beams to the coherent photodetector module; the coherent photodetector module includes a silicon photomultiplier tube, which outputs the first and second electrical signals to the differential amplifier circuit module; the differential amplifier circuit module outputs the differentially amplified signal to the physicochemical parameter inversion and solution module; the ambient temperature sensing module outputs the measured ambient temperature value to the physicochemical parameter inversion and solution module; the physicochemical parameter inversion and solution module outputs a pesticide supplementation spraying warning signal to the flag leaf of the wheat to be tested, and outputs the residual mass concentration of fungicide and the degree of fungal cell membrane damage through collaborative solution.

[0058] Example 5: The distance sensing component in the portable sensing probe module monitors the relative position between the probe tip and the surface of the wheat flag leaf to be measured in real time, and feeds back the deviation of the non-contact measurement distance to the drive control circuit in the signal processing box. When the measurement distance exceeds the preset range of 12mm to 18mm, the drive control circuit cuts off the pulse trigger signals of the 340nm ultraviolet semiconductor laser and the blue semiconductor laser. When the probe distance is too small, this avoids the probe from scratching the frost on the leaf surface. When the distance is too large, it avoids the quartz fiber guide beam from receiving natural light scattering background outside the numerical aperture range of 0.22, which would cause signal overload.

[0059] Before the detection was initiated, the system loaded an offline calibration database and discretely sampled the dark current of the two photoelectric sensing submodules under different illumination and temperature conditions in a dark room to construct the ambient temperature measurement value. The dark signal compensation matrix, which is in the range of 10℃ to 35℃, is calibrated by two-dimensional sampling with a temperature step of 1℃ and an illuminance step of 100lx. The static dark current voltage value output by the silicon photomultiplier tube at each temperature and illuminance intersection node is recorded. For intermediate nodes that are not directly sampled, the physical and chemical parameter inversion solution module uses a bilinear interpolation algorithm to complete the matrix grid and form a continuous two-dimensional compensation data table.

[0060] During field testing, the ambient temperature sensing module collects measurements of the ambient temperature at the site. The physical and chemical parameter inversion and solution module simultaneously reads the current illuminance and locates adjacent nodes in the dark signal compensation matrix through two-dimensional indexing. It then interpolates the corresponding node data to obtain the target bias compensation amount under the current temperature and illuminance conditions. The gain circuit outputs a correction current according to this compensation amount to offset the baseline drift caused by thermal noise, thereby ensuring the measurement intensity of the bactericide-specific emission peak. and blade reflection reference intensity Maintain a linear response in the analog electrical signal preamplifier stage.

[0061] During long-term monitoring, the physicochemical parameter inversion and solution module in the signal processing box updates the baseline parameters using a sliding time window. This module calculates the baseline fluorescence lifetime of untreated healthy wheat leaves over the past 50 monitoring cycles. The measured mean is used to weight and update the reference parameters in the register with an attenuation factor of 0.95, which is used to correct the pulse full width attenuation caused by laser aging and the response drift of silicon photomultiplier tube.

[0062] When the peak response of the first photoelectric sensing submodule using a silicon photomultiplier tube for 10 consecutive pulses is lower than the preset signal-to-noise ratio threshold, the physical parameter inversion calculation module triggers a gain calibration program, controls the high-speed analog-to-digital conversion circuit to adjust the range, and adjusts the differential amplifier circuit module to improve the in-phase rejection ratio, while the fluorescence average lifetime change... During the calculation process, the physical parameter inversion solution module calculates the 100ns attenuation acquisition window. The attenuation slope of the inner integral waveform envelope is used to correct the polarization potential deviation caused by residual high background radiation; after correction, the residual mass concentration of the bactericide is... and degree of fungal cell membrane damage The discrete solution results are written to the output register.

[0063] Example 6: When dust adheres to the probe objective window or transmission loss occurs in the quartz fiber beam guide, the detection system first performs pre-calibration to redefine the signal gain reference for the two spectral channels. During calibration, the portable sensing probe module is fixed at a distance of 15mm from the diffuse reflection calibration plate, and a 340nm ultraviolet semiconductor laser is driven to emit calibration pulse trains. The first photoelectric sensing submodule acquires the calibration intensity of the 460nm channel, and the second photoelectric sensing submodule acquires the calibration intensity of the full spectrum channels from 400nm to 700nm. The microprocessor in the signal processing box compares the amplitudes of the two output voltages and adjusts the bias voltage power supply of the two photoelectric sensing submodules to bring the static gain mismatch under the background of no fluorescence scattering to within 0.1%.

[0064] After gain calibration, the static thermal noise baseline of the two photoelectric sensing submodules was acquired in a darkroom shielded state, and the zero-point bias voltage of the differential amplifier circuit module was adjusted to 0mV. When no ultraviolet fluorescence pulse arrives, the differential output is kept at zero to reduce the impact of stray drift of the front-end analog circuit on the nanosecond-level attenuation response calculation.

[0065] The high-speed analog-to-digital converter circuit receives a phase-locked demodulation trigger signal synchronized with the 100kHz ultraviolet pulse light. The microprocessor controls the programmable delay phase-locked loop circuit to align the 1GS / s analog-to-digital conversion sampling clock with the emission time of the 340nm ultraviolet pulse light, with a 100ns attenuation acquisition window within a single pulse period. The entire fluorescence decay waveform induced by the first wavelength pulse light with a full width at half maximum (FWHM) of 2.5 ns is covered.

[0066] During hardware operation, the programmable delay phase-locked loop circuit receives a 100kHz synchronous in-phase square wave output from the ultraviolet semiconductor laser drive control circuit. This wave is then locked and up-frequencyed to 1GS / s by an internal high-frequency multiplier, serving as the sampling trigger frequency for the high-speed analog-to-digital converter circuit. When the ultraviolet pulse light is emitted, the phase-locked demodulation circuit opens a high-speed acquisition gate signal with a duration of 100ns. The high-speed analog-to-digital converter circuit continuously acquires 100 discrete voltage data points at a sampling interval of 1ns and writes them into the dual-port high-speed cache.

[0067] The physicochemical parameter inversion and solution module calls a fixed-point parallel accumulator to perform in-phase superposition and average filtering on voltage values ​​at the same relative time position in multiple consecutive pulse cycles. This reduces random high-frequency noise while preserving the time-domain profile of the nanosecond-level fluorescence decay waveform. Subsequently, 100 discrete sampling points in the cache are read and integrated to obtain the average fluorescence lifetime change. .

[0068] In 50 consecutive assays of untreated healthy wheat leaves, the baseline fluorescence lifetime of untreated healthy wheat leaves was... If the dispersion is greater than 2%, the physicochemical parameter inversion solution module re-determines the change in fluorescence mean lifetime. The reference term used in the calculation is based on the initial fluorescence after the second wavelength pulse light is emitted. and maximum fluorescence Calculate variable fluorescence When chlorophyll reaches its maximum photochemical quantum yield When the value is below 0.50, the flag leaf of the wheat to be tested is marked as a diseased state.

[0069] The physicochemical parameter inversion and calculation module reads the preset safety threshold and preset inactivation threshold from the pre-calibrated benchmark parameters, and compares the residual mass concentration of the fungicide. and degree of fungal cell membrane damage ,when Higher or lower than the preset safety threshold, and When the value is below the preset inactivation threshold, and Write to the output register to generate a warning signal for supplemental pesticide application, and send it to the display output module.

[0070] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A field efficacy quantitative detection system for a wheat rust fungicide, characterized in that, Include: The time-division high-frequency pulse excitation module is used to alternately emit the first wavelength pulse light that induces the intrinsic fluorescence of fungicides and pathogens, and the second wavelength pulse light that induces the photochemical response of leaf chlorophyll. The coaxial light acquisition module includes a polarization extinction balancing submodule, a coaxial beam splitting submodule, a first spectral channel module, and a second spectral channel module. The polarization extinction balancing submodule includes a quarter-wave plate assembly set in the front-end optical path of the coaxial beam splitting submodule, which is used to convert the dynamically reflected polarized light from wheat leaves into orthogonal polarization states. The coaxial beam splitting module is used to decompose the acquired beam into a first beam and a second beam. The first spectral channel module is equipped with a target fluorescence bandpass filter, and the second spectral channel module is equipped with a full-spectrum compensation filter. The coherent photoelectric detection module includes a first photoelectric sensing submodule and a second photoelectric sensing submodule connected to a first spectral channel module and a second spectral channel module, respectively, and a differential amplifier circuit module whose input terminals are connected to the first photoelectric sensing submodule and the second photoelectric sensing submodule, respectively. The first photoelectric sensing submodule and the second photoelectric sensing submodule output a first electrical signal and a second electrical signal, respectively. The differential amplifier circuit module is used to perform physical differential subtraction on the first electrical signal and the second electrical signal to remove ambient sunlight background and polarization flicker noise. The physicochemical parameter inversion and solution module is connected to the coherent photoelectric detection module to receive the differentially amplified signal. Based on the nanosecond-level decay response and photochemical induced kinetics, it calculates the residual mass concentration of fungicide and the degree of fungal cell membrane damage.

2. The field efficacy quantitative detection system for wheat rust fungicide according to claim 1, characterized in that, The first wavelength pulse light emitted by the time-division high-frequency pulse excitation module is ultraviolet pulse light with a center wavelength of 300nm to 350nm and a linewidth of 2nm to 6nm, which is used to induce the intrinsic fluorescence of fungicide active molecules and ergosterol in pathogens; the second wavelength pulse light emitted by the time-division high-frequency pulse excitation module is blue light pulse with a center wavelength of 400nm to 550nm and a linewidth of 2nm to 7nm, which is used to induce the fast photochemical fluorescence induced kinetic response of wheat leaf chlorophyll; the target fluorescence bandpass filter set in the first spectral channel module has a center wavelength of 420nm to 500nm and a bandwidth of 8nm to 12nm, and the full-spectrum compensation filter set in the second spectral channel module covers the transmission band of 400nm to 700nm.

3. The field efficacy quantitative detection system for wheat rust fungicide according to claim 1, characterized in that, The coaxial light acquisition module also includes a quartz fiber beam guide and objective lens with a numerical aperture of 0.

22. The coaxial beam splitting submodule is a 50:50 non-polarized beam splitting cube. The quarter-wave plate assembly adjusts the reflected polarized light generated by the wind-induced micro-shaking of the wheat leaf surface to a phase-orthogonal state, so that the background light noise entering the first photoelectric sensing submodule and the second photoelectric sensing submodule remains synchronized in amplitude and phase.

4. The field efficacy quantitative detection system for wheat rust fungicide according to claim 1, characterized in that, The system also includes an ambient temperature sensing module, and a physicochemical parameter inversion and calculation module that is signal-connected to the ambient temperature sensing module. The physicochemical parameter inversion and calculation module establishes a logarithmic mapping relationship between the measured intensity of the fungicide-specific emission peak and the reference intensity of the leaf reflection. Based on the temperature difference between the measured ambient temperature value collected in real time by the ambient temperature sensing module and the 25℃ standard reference temperature, the module performs linear temperature correction on the logarithmic ratio of the measured intensity of the fungicide-specific emission peak and the reference intensity of the leaf reflection through a preset temperature compensation coefficient, so as to calculate the residual mass concentration of the fungicide.

5. The field efficacy quantitative detection system for wheat rust fungicide according to claim 1, characterized in that, The physicochemical parameter inversion and solution module establishes a nonlinear coupling relationship between the change in average fluorescence lifetime and the maximum photochemical quantum yield of chlorophyll, and calculates the degree of fungal cell membrane damage. The maximum photochemical quantum yield of chlorophyll is calculated by the physicochemical parameter inversion and solution module based on the initial fluorescence and maximum fluorescence collected under second wavelength pulsed light excitation. The degree of fungal cell membrane damage reflects the synergistic effect of physical relaxation changes caused by fungal cell membrane rupture and plant photochemical toxicity response.

6. The field efficacy quantitative detection system for wheat rust fungicide according to claim 1, characterized in that, Both the first and second photoelectric sensing submodules are silicon photomultiplier tubes, and their output terminals are directly connected to the positive and negative input terminals of the differential amplifier circuit module with a bandwidth of not less than 200MHz. The coherent photodetector module also includes a high-speed analog-to-digital converter circuit connected to the output terminal of the differential amplifier circuit module and a 100kHz phase-locked demodulation circuit synchronized with the time-division high-frequency pulse excitation module. The sampling rate of the high-speed analog-to-digital converter circuit is 0.5GS / s to 1.5GS / s, which is used to perform digital high-frequency sampling on the differentially amplified electrical signal and extract the nanosecond-level attenuation signal.

7. The field efficacy quantitative detection system for a wheat rust fungicide according to claim 1, characterized in that, The time-division high-frequency pulse excitation module includes an ultraviolet semiconductor laser and a blue semiconductor laser. The ultraviolet semiconductor laser has a pulse full width at half maximum (FWHM) of 1.5 ns to 3.5 ns and a repetition rate of 80 kHz to 130 kHz, used to generate the first wavelength pulse light. The blue semiconductor laser has a pulse FWHM of 2 ns to 6 ns, used to generate the second wavelength pulse light. The time-division high-frequency pulse excitation module also includes a drive control circuit, which drives the ultraviolet semiconductor laser to emit pulse trains with a single pulse duration of 9 ns to 13 ns and a repetition period of 8 μs to 13 μs, and drives the blue semiconductor laser to emit light with an intensity of 2500 μmol·m. -2 ·s -1 Up to 3500 μmol·m -2 ·s -1 Furthermore, it consists of continuous saturation pulses with a pulse width ranging from 80ms to 120ms.

8. The field efficacy quantitative detection system for wheat rust fungicide according to claim 1, characterized in that, The system includes a portable sensor probe module and a signal processing box. The portable sensor probe module has a built-in coaxial light acquisition module and a time-division high-frequency pulse excitation module. The front end of the portable sensor probe module is placed above the surface of the wheat flag leaf to be tested and maintains a non-contact measurement distance of 15mm. The front end of the portable sensor probe module also includes a distance sensing component, which is used to monitor the relative position between the portable sensor probe module and the surface of the wheat flag leaf to avoid physical contact that could damage the distribution and physiological activity of the pesticide coating on the wheat leaf surface.

9. The field efficacy quantitative detection system for a wheat rust fungicide according to claim 1, characterized in that, The system also includes a display output module, and a physicochemical parameter inversion and calculation module is connected to the display output module. The physicochemical parameter inversion and calculation module has pre-calibrated benchmark parameters built in, and generates a supplementary spraying warning signal when the calculated fungicide residue concentration is higher or lower than a preset safety threshold and the fungal cell membrane damage degree is lower than a preset inactivation threshold. The display output module is used to display the fungicide residue concentration, fungal cell membrane damage degree and supplementary spraying warning signal in real time.

10. A method for quantitative field efficacy detection of a wheat rust fungicide, used to implement the quantitative field efficacy detection system for wheat rust fungicide described in claim 1, characterized in that, Include: Step S101: The time-division high-frequency pulse excitation module alternately emits a first wavelength pulse light that induces the intrinsic fluorescence of the fungicide and the pathogen, and a second wavelength pulse light that induces the photochemical response of leaf chlorophyll. Step S102: The beam of light radiated from the surface of wheat leaves is collected by the coaxial light acquisition module. The quarter-wave plate component in the polarization extinction balance submodule converts the dynamically reflected polarized light from the cuticle of the wheat leaf epidermis into an orthogonal polarization state. The beam is then decomposed into a first beam and a second beam by the coaxial beam splitting submodule, and directed to the first spectral channel module and the second spectral channel module, respectively. Step S103: The first photoelectric sensing submodule and the second photoelectric sensing submodule in the coherent photoelectric detection module receive the first beam and the second beam respectively and output the first electrical signal and the second electrical signal. The differential amplifier circuit module performs physical differential subtraction on the first electrical signal and the second electrical signal to remove the ambient sunlight background and polarization flicker noise. Step S104: Receive the differentially amplified signal through the physicochemical parameter inversion solution module, and calculate the residual mass concentration of the fungicide and the degree of fungal cell membrane damage based on the nanosecond-level decay response and photochemical induced kinetics.

Images