A kind of off-line autonomous and remote monitoring field plant canopy fluorescence active detection equipment

Abstract

The application provides a kind of off-line autonomous and remote monitoring field plant canopy fluorescence active detection equipment, belongs to the field of plant physiological ecology detection technology.The equipment includes fluorescence detection module, excitation light driving module, main control module, remote monitoring and storage module and power module;Among them, the fluorescence detection module uses pulse amplitude modulation and lock-in amplification technology to separate ambient light and chlorophyll fluorescence;The excitation light driving module adjusts the excitation light intensity and irradiation range through programmable voltage and beam expander;The main control module has programmable measurement timing, supports off-line autonomous cyclic acquisition;Remote monitoring and storage module realizes remote parameter configuration and local data reading through WiFi.The application solves the problems of existing plant canopy fluorescence active detection equipment in the field, such as large environmental light interference, difficult to adjust excitation light irradiation range and frequent dependence on manual operation, realizes the reliability, stability and off-line measurement of field plant canopy fluorescence.

Description

Technical Field

[0001] This invention relates to an offline autonomous and remote monitoring active detection device for fluorescence in the canopy of wild plants, belonging to the field of plant physiological and ecological detection technology. Background Technology

[0002] Chlorophyll fluorescence is a weak signal released by plants during photosynthesis, reflecting their photosynthetic efficiency, response to environmental stress, and physiological state. Therefore, developing active detection devices capable of stably measuring plant fluorescence is of great significance.

[0003] Currently, active fluorescence detection equipment for plants is mainly used in laboratories or artificially controlled environments. Because the ambient light in these environments is relatively stable, existing equipment can easily measure stable fluorescence signals. However, in field environments, the weak fluorescence signals produced by plants are easily interfered with by ambient light, making it difficult to guarantee the accuracy and stability of the fluorescence signals.

[0004] Existing active fluorescence detection devices for plant canopies require continuous manual or external computer control, which is not conducive to long-term field monitoring. Furthermore, different plants exhibit variations in the intensity and range of excitation light, necessitating adjustments to the excitation light for different plants.

[0005] Therefore, there is an urgent need to provide an active detection device for plant canopy fluorescence that is suitable for field environments. Through technologies such as excitation light modulation, fluorescence and ambient light separation, programmable autonomous measurement, local data storage, and wireless remote monitoring, it is possible to achieve long-term, stable, and offline autonomous measurement of plant canopy fluorescence in the field, thereby improving the convenience and reliability of plant canopy fluorescence detection in the field. Summary of the Invention

[0006] This invention provides an offline autonomous and remote monitoring field plant canopy fluorescence detection device and its detection method, aiming to solve the problems of existing active plant canopy fluorescence detection devices being greatly affected by ambient light in the field, having difficulty adjusting the excitation light irradiation range, and requiring frequent manual operation, thereby improving the stability and reliability of field plant canopy fluorescence detection.

[0007] The main control module outputs an excitation light driving signal to control the excitation light driving module to output corresponding excitation light to induce chlorophyll fluorescence in the plant canopy; the excitation light driving module outputs excitation light of different intensities and irradiation ranges by adjusting the programmable voltage and the beam expander.

[0008] The fluorescence detection module collects ambient light and induced chlorophyll fluorescence from the plant canopy. The detector converts the photoelectric signal into a photoelectric signal and uses pulse amplitude modulation and lock-in amplification technology to separate the fluorescence and ambient light.

[0009] The main control module has a built-in programmable measurement timing sequence, which synchronously excites the light drive signal and the acquisition signal to complete signal acquisition, preprocessing and transmission, and automatically cyclically acquires data without external instructions.

[0010] The remote monitoring and storage module receives signal data transmitted from the main control module for data storage, and enables remote parameter configuration and local data retrieval via WiFi and remote terminal; the power module provides operating voltage for each module of the device.

[0011] The detection method first sends configuration parameters via a remote terminal to determine the sampling mode, sampling time interval, and excitation pulse width;

[0012] Adjust the programmable voltage and the beam expander size to set the excitation light intensity and illumination range;

[0013] The main control module outputs the corresponding excitation light driving signal according to the parameter configuration. The driving circuit drives the excitation light source to emit excitation light, and then the beam expander expands the beam to induce the plant canopy to produce fluorescence.

[0014] The fluorescence detection module collects fluorescence signals induced by ambient light and plant canopy, and realizes photoelectric signal conversion and signal separation and conditioning;

[0015] The main control module converts analog signals into digital signals through an ADC conversion circuit, and works with the MCU control circuit to perform synchronous data acquisition and preprocessing.

[0016] The main control module transmits the processed data to the remote monitoring and storage module, waiting for the remote terminal to request the data to be read from the local storage.

[0017] If no stop data acquisition command is received from the remote terminal and the device is not powered off, the measurement task will continue; otherwise, the measurement task will end. Attached Figure Description

[0018] The present invention will be further described below with reference to the accompanying drawings and examples.

[0019] Figure 1 This is a structural diagram of the device according to an embodiment of the present invention;

[0020] Figure 2 This is a flowchart of the excitation light driving module according to an embodiment of the present invention;

[0021] Figure 3 This is a flowchart of the fluorescence detection module according to an embodiment of the present invention;

[0022] Figure 4 This is a test scenario diagram from an embodiment of the present invention;

[0023] Figure 5 This is a graph showing the test results in an embodiment of the present invention. Detailed Implementation

[0024] To make the objectives and technical solutions of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0025] like Figure 1 As shown, the offline autonomous and remote monitoring active detection device for field plant canopy fluorescence provided in this embodiment of the invention includes:

[0026] S1, Fluorescence Detection Module: Includes a receiving optical path, a detector, and a modulation separation circuit. The output of this module is electrically connected to the input of the main control module.

[0027] S11, the receiving optical route consists of a Fresnel lens with a diameter of 160mm and a focal length of 70mm and a bandpass filter of 600-800nm. The Fresnel lens is fixed at the front end of the detector, and the bandpass filter is fixed at the front end of the detector, which are used to focus and filter the optical signal respectively.

[0028] S12 uses a silicon photodiode detector S1277-1010BR from Hamamatsu, Japan, with a light-receiving surface of 10x10mm and a wavelength of 340-1000nm. The detector is fixed together with the filter and the distance between it and the Fresnel lens is 70mm. The working mode is light guide mode.

[0029] S13, the modulation separation circuit amplifies the transimpedance of the electrical signal converted by the detector, and through filtering, separation and amplification, finally outputs the AC chlorophyll fluorescence signal and the DC ambient light signal.

[0030] S2, the excitation light driving module consists of an excitation light source, a programmable voltage regulation circuit, an excitation light driving circuit, and a beam expander. This module controls the opening and closing of the excitation light source through the excitation light driving signal output by the main control module, and its signal input terminal is connected to the main control module.

[0031] S21 uses a 450nm laser diode with a peak power of 5W as the excitation source. The excitation light path emitted by the laser diode is coaxial with the receiving light path of the fluorescence detection module.

[0032] S22, the programmable voltage regulator circuit can convert an input voltage of 4.5-21V to an output voltage of 3-21V;

[0033] S23, the excitation light driving circuit is a constant voltage driving circuit, used to receive excitation light driving signals with different pulse widths;

[0034] S24, the beam expander is a beam expander with a wavelength of 390-1100nm and a diameter of 8mm, which is fixed on the emission path of the laser diode;

[0035] S3, the main control module consists of an ADC conversion circuit and an MCU control circuit, and this module is connected to each other module;

[0036] S31, the input of the ADC conversion circuit is the output of the fluorescence detection module, which converts the analog signal into a digital signal and outputs it to the MCU control circuit;

[0037] S32, the MCU control circuit is connected to the excitation light driving module, the remote monitoring and storage module and the ADC circuit respectively, and is used for driving the excitation light and synchronous acquisition, preprocessing and transmission of data;

[0038] S4, the remote monitoring and storage module, consists of a WiFi module and a local storage module, and is connected to the main control module.

[0039] S41, the WiFi module is used to receive terminal operation commands and transmit data to the local storage module, and can read the stored data at any time;

[0040] S42, the local storage module uses a high-capacity SD card as the local storage medium to store the collected data in real time;

[0041] S5, the power module consists of a lithium battery and a voltage conversion circuit. This module provides the working voltage to each module of the device and is connected to each module.

[0042] The S51 uses a rechargeable lithium battery pack to provide independent power for the device.

[0043] The S52 voltage conversion circuit converts the lithium battery output voltage into various operating voltages required by each module, achieving stable and independent power supply.

[0044] The specific working method and process of the active detection device for fluorescence in the canopy of wild plants, which provides offline autonomous and remote monitoring capabilities based on the above embodiments, are as follows:

[0045] Turn on the device and connect the remote terminal to the device via WiFi;

[0046] The remote terminal determines the sampling mode as continuous sampling, sets the time interval to 1 minute, and outputs an excitation light drive signal with a pulse width of 5µs, a period of 10ms, and a duration of 1s.

[0047] The output voltage of the programmable voltage circuit is adjusted to 12V, and the divergence angle of the beam expander is controlled to 30° by rotating the lens barrel.

[0048] like Figure 4 As shown, adjust the height between the device and the pothos canopy so that the distance between the device and the leaves of the pothos canopy is 1.3m, to ensure that the device can fully excite and detect the fluorescence of the pothos canopy;

[0049] like Figure 2 As shown, the excitation light driving signal output by the main control module according to the parameter configuration is transmitted to the excitation light driving circuit, and the laser diode outputs the excitation light with the above parameters under the drive;

[0050] The excitation light is expanded by a beam expander along the emission path to increase the irradiation range of the excitation light, which is then irradiated onto the canopy leaves of the pothos, inducing it to emit chlorophyll fluorescence.

[0051] like Figure 3 As shown, the chlorophyll fluorescence, ambient light and other interfering light excited by the pothos are collected by a Fresnel lens and focused onto a bandpass filter. The bandpass filter filters out interfering light outside the bandpass band range, and the filtered light is transmitted to the detector.

[0052] With the anode connected to -9V, the silicon photodiode detector outputting from the cathode converts the filtered optical signal into an electrical signal, at which point the detector operates in photoconductive mode.

[0053] The modulation separation circuit obtains pure chlorophyll fluorescence signal and ambient light signal by filtering, separating and amplifying electrical signals;

[0054] The ADC conversion circuit in the main control module converts the pure ambient light signal and chlorophyll fluorescence signal output by the fluorescence detection module into digital signals that can be acquired by the MCU control circuit.

[0055] The MCU control circuit acquires digital signals and synchronously excites the light drive signal and the acquisition signal. Then, the acquisition signal is preprocessed and the processed data is transmitted to the remote monitoring and storage module.

[0056] The remote monitoring and storage module receives data transmitted by the MCU control circuit and stores the data on the SD card; the WiFi module waits for data read requests and operation commands sent by the remote terminal.

[0057] If no stop acquisition command is received from the remote terminal and the device is not powered off, the main control module controls the device to automatically collect data in a loop according to the programmable measurement sequence without external commands, until a stop acquisition command is received or the power is cut off.

[0058] Figure 5 The graphs showing the test results in this embodiment of the invention clearly demonstrate the changes in chlorophyll fluorescence of the pothos canopy and ambient light throughout the day.

[0059] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Those skilled in the art will recognize that the present invention can undergo various modifications and variations. Several improvements and modifications can be made without departing from the technical solution of the present invention, and all such modifications and variations should be included within the scope of protection of the present invention.

Claims

1. An offline autonomous and remote monitoring active detection device for fluorescence in the canopy of wild plants, characterized in that, include: The fluorescence detection module is used to collect ambient light and chlorophyll fluorescence from the plant canopy, convert them into electrical signals that can be collected, and uses pulse amplitude modulation and lock-in amplification technology to separate the fluorescence signal from the ambient light signal. The excitation light driving module is used to induce chlorophyll fluorescence in the plant canopy. Combined with a programmable voltage and a beam expander, it can adjust the excitation light brightness and irradiation range to meet the light requirements of different plants. The main control module has a built-in programmable measurement timing sequence, which completes the conversion and preprocessing of the acquired signals, and synchronously excites the optical drive signal and the acquired signal. It can automatically and cyclically acquire data according to the programmable measurement timing sequence without external instructions. The remote monitoring and storage module is used to store the collected data and enable remote parameter configuration and local data retrieval via WiFi to a remote terminal; The power supply module is used to provide operating voltage to the various modules of the device.

2. The device according to claim 1, characterized in that, The fluorescence detection module includes a receiving optical path, a detector, and a modulation separation circuit, which respectively complete the collection of ambient light and fluorescence, the conversion of photoelectric signals, and the separation and amplification of ambient light and fluorescence.

3. The device according to claim 1, characterized in that, The excitation light driving module includes an excitation light source, a programmable voltage regulating circuit, an excitation light driving circuit, and a beam expander. By adjusting the voltage, the intensity of the output excitation light can be controlled. The beam expander is set in the light path of the excitation light source to expand the irradiation range of the excitation light on the plant canopy.

4. The device according to claim 1, characterized in that, The main control module includes: an ADC conversion circuit, whose input is connected to the fluorescence detection module and whose output is connected to the MCU control circuit, converting the analog signal output by the fluorescence detection module into a digital signal; and an MCU control circuit, which outputs an excitation light driving signal, synchronously acquires and preprocesses data, transmits the acquired data and receives operation instructions from the terminal, and coordinates the work of each module.

5. The device according to claim 1, characterized in that, The remote monitoring and storage module includes a WiFi module and a local storage module. The local storage module stores the collected data transmitted by the main control module for remote terminals to read. The WiFi module is used for wireless communication with the remote terminal, receiving terminal commands, and realizing remote parameter configuration and local data reading.

6. The device according to claim 1, characterized in that, The power module includes a lithium battery and a voltage conversion circuit. The lithium battery is used to supply power, and the voltage conversion circuit is used to convert the lithium battery voltage into the operating voltage required by each module, ensuring that each module can work independently and stably.

7. The device according to claim 1, characterized in that, It also includes a housing and structural fasteners for assembling the various modules into a portable field exploration device.

8. A method for active detection of fluorescence in plant canopies in the field based on the device described in any one of claims 1 to 7, characterized in that, Includes the following steps: Step 1: The remote terminal sends configuration parameters to determine the sampling mode, sampling time interval, and excitation pulse width; Step 2: Adjust the programmable voltage and the beam expander size to set the intensity and irradiation range of the excitation light; Step 3: The main control module outputs the corresponding excitation light driving signal according to the parameter configuration. The driving circuit drives the excitation light source to emit excitation light, which is then expanded by the beam expander to induce fluorescence in the plant canopy. Step 4: The fluorescence detection module collects fluorescence signals induced by ambient light and plant canopy, and realizes photoelectric signal conversion and signal separation and conditioning; Step 5: The main control module converts the analog signal into a digital signal through the ADC conversion circuit, and works with the MCU control circuit to perform data acquisition and preprocessing; Step Six: The main control module transmits the processed data to the remote monitoring and storage module, waiting for the remote terminal to request the data to be read from the local storage. Step 7: If no stop data acquisition command is received from the remote terminal and the device is not powered off, return to Step 3 to continue execution; otherwise, end the measurement task.

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