A method and device for in-situ detection of moisture in corn stalks

Abstract

The application discloses a corn stalk moisture in-situ detection method and device, and belongs to the cross technical field of agricultural detection technology and optical sensing technology. The method comprises the following steps: selecting a to-be-detected area of the corn stalk, and pretreating the surface of the corn stalk; performing contact scanning on the to-be-detected area of the corn stalk based on a corn stalk moisture in-situ detection device; obtaining the absorption coefficient of the corn stalk; correlating the absorption coefficient of the corn stalk with the corresponding moisture; and solving the moisture of the corn stalk. The application effectively overcomes the problem that the traditional spectrum method is dependent on reflectance / transmittance and is greatly interfered by physical structure, and through the cooperative detection of the reflection and semi-transmission double optical paths and the combination of the absorption coefficient inversion model, the precision and anti-interference ability of the corn stalk moisture in-situ detection are significantly improved. The device is compact in structure, simple in operation, supports field rapid measurement and whole plant moisture evaluation, and provides an efficient and reliable technical means for the utilization of straw resources.

Description

Technical Field

[0001] This invention relates to the interdisciplinary field of agricultural detection technology and optical sensing technology, specifically to a method and device for in-situ detection of moisture in corn stalks. Background Technology

[0002] Moisture content testing of corn stalks is extremely helpful in estimating corn stalk resource quantity. Traditional methods for calculating corn stalk resource quantity require drying, which is time-consuming and labor-intensive. There is an urgent need to develop convenient and accurate corn stalk moisture content testing equipment; employing effective testing technology is a prerequisite for the design and development of such equipment.

[0003] Optical detection, as the most widely used detection technology, is characterized by its green and rapid nature, and can detect internal quality indicators of agricultural products, such as moisture content. In corn stalks, traditional spectroscopic methods mainly measure the reflection or transmission signals of light by substances, establishing a relationship with the analyte through mathematical models. This method is heavily reliant on measurement methods and equipment, resulting in poor repeatability and hindering its widespread application in in-situ rapid testing at stalk production sites. Measurements of the non-destructive absorption and scattering optical properties of substances utilize the intrinsic properties of light interaction with plant tissues, are independent of instruments and detection methods, and have greater generalizability. However, existing technologies for internal quality detection are mainly designed for economic crops such as fruits and vegetables, and are not suitable for on-site moisture detection in corn stalks.

[0004] To address the aforementioned issues, there is an urgent need for an in-situ method and device for detecting moisture in corn stalks, which can solve the problems associated with traditional methods. Summary of the Invention

[0005] The purpose of this invention is to provide a method and device for in-situ detection of moisture in corn stalks, which effectively overcomes the problems of traditional spectroscopic methods that rely on reflectance / transmittance and are greatly affected by physical structure. By using dual-path detection of reflectance and semi-transmittance light, combined with an absorption coefficient inversion model, the accuracy and anti-interference ability of in-situ detection of moisture in corn stalks are significantly improved. The device of this invention has a compact structure and is easy to operate, supporting rapid field measurement and whole-plant moisture assessment, providing an efficient and reliable technical means for the resource utilization of straw.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for in-situ detection of moisture in corn stalks, comprising:

[0008] Step 1: Select the area of ​​corn stalk to be tested and pre-treat its surface;

[0009] Step 2: Using a corn stalk moisture in-situ detection device, perform contact scanning on the test area of ​​the corn stalk to obtain the absorption coefficient of the corn stalk.

[0010] Step 3: Correlate the absorption coefficient of corn stalks with the corresponding moisture content to determine the moisture content of the corn stalks.

[0011] Further, in step 1, the area to be tested from the corn stalks is selected, specifically as follows:

[0012] Select corn stalks with a diameter greater than 15mm, and define the area to be measured as a semi-cylinder extending 6mm vertically upwards and downwards from the point light source as the center.

[0013] Furthermore, in step 1, the surface pretreatment of the test area of ​​the corn stalk is performed, specifically as follows:

[0014] Remove interfering factors from the surface of the test area of ​​the corn stalk, including withered, yellowish-brown or blackish-brown leaf sheaths and water droplets on the surface of the corn stalk.

[0015] Further, in step 2, the corn stalk moisture in-situ detection device is used to perform contact scanning on the test area of ​​the corn stalk to obtain the absorption coefficient of the corn stalk, specifically as follows:

[0016] The in-situ moisture detection device for corn stalks uses both reflective and semi-transmittance optical paths to perform contact scanning on the test area of ​​the corn stalks, thereby retrieving the absorption coefficients of the cortex and medulla of the corn stalks.

[0017] Furthermore, the contact scanning uses characteristic wavelengths of 850nm and 950nm, with a wavelength resolution of no less than 20nm.

[0018] Furthermore, in step 3, the relationship between the absorption coefficient of the corn stalk and its corresponding moisture content is correlated to determine the moisture content of the corn stalk. Specifically:

[0019] The relationship between the absorption coefficients of corn stalk cortex and medulla and the corresponding moisture content of corn stalks is as follows:

[0020] (1)

[0021] (2)

[0022] In the formula, This refers to the moisture content of the cortex. Water content of medulla The absorption coefficient was measured at a wavelength of 950 nm. The absorption coefficient was measured at a wavelength of 850 nm.

[0023] The moisture content of corn stalks, calculated based on the cortical and medullary moisture contents, is as follows:

[0024] (3)

[0025] In the formula, This refers to the moisture content of the straw.

[0026] The present invention also provides a corn stalk moisture in-situ detection device, applied to the above-mentioned corn stalk moisture in-situ detection method, comprising: a detection head, a handle, a clamping mechanism and a control module, wherein the clamping mechanism is disposed on the handle, and the detection head and the control module are disposed on the clamping mechanism, the detection head is connected to the control module, and the handle is used to insert the corn stalk into its interior, and perform in-situ moisture detection based on the detection head.

[0027] Furthermore, the detection head includes a light source emitting head, a first light source receiving head, and a second light source receiving head. The light source emitting head is disposed inside the clamping mechanism, and the first light source receiving head is disposed below the light source emitting head. The two are collinear in the vertical direction. The second light source receiving head is also disposed inside the clamping mechanism, and the second light source receiving head forms a 45° angle with the first light source receiving head on the horizontal plane. The first light source receiving head is used to collect reflected light, and the second light source receiving head is used to collect semi-transparent light. The light source emitting head, the first light source receiving head, and the second light source receiving head are connected to the control module.

[0028] Furthermore, the light source emitting head is composed of an integrated LED light source, a heat sink, a convex lens, and a reflector, and both the first light source receiving head and the second light source receiving head are composed of a photodiode and a filter.

[0029] Furthermore, the control module includes a signal acquisition module, a signal conditioning module, and a data storage and analysis module.

[0030] In summary, the present invention has at least one of the following beneficial technical effects:

[0031] 1. This invention can overcome the spatial heterogeneity of moisture content in intact corn stalks in the field, and can overcome the interference of changes in stalk diameter on moisture measurement, which is beneficial for accurately measuring the moisture content of whole corn stalks.

[0032] 2. This invention helps operators quickly assess the amount of straw resources per unit area of ​​cultivated land on-site, thus improving the efficiency of straw resource assessment.

[0033] 3. This invention has two modes: local moisture measurement and whole-plant moisture measurement, which meet the detection needs of field workers at different observation scales.

[0034] 4. This invention optimizes the parameters of the inversion procedure and prediction model, saving time and costs associated with on-site testing;

[0035] 5. The color and appearance of the buttons in this invention correspond one-to-one with their functions, making it easy for operators to understand and use. The test results are simultaneously displayed on the screen and stored in the SD card, facilitating on-site data observation and subsequent data processing. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of a contact scanning method;

[0037] Figure 2 A diagram showing the buttons on the controller;

[0038] Figure 3a This is a top view of the device of the present invention;

[0039] Figure 3b This is a front view of the device of the present invention;

[0040] Figure 4 This is a block diagram of the control module structure.

[0041] Figure 5 This is a schematic diagram of the control module's control flow.

[0042] Figure 6 This is a schematic diagram of the method flow of the present invention;

[0043] Figure 7 A schematic diagram of a corn stalk medulla spectrophotometric dataset;

[0044] Figure 8 A schematic diagram of the spectral transmission data of corn stalk medulla;

[0045] Figure 9 A schematic diagram of the corn stalk cortical reflectance spectrum dataset;

[0046] Figure 10 A schematic diagram of the transmission spectrum dataset of corn stalk cortex;

[0047] Figure 11 A schematic diagram of the absorption coefficient of corn stalk medulla;

[0048] Figure 12 A schematic diagram of the absorption coefficient of corn stalk cortex;

[0049] Figure 13 A schematic diagram of sampling the absorption coefficient of corn stalk medulla;

[0050] Figure 14 A schematic diagram of sampling the absorption coefficient of corn stalk cortex;

[0051] Figure 15 A schematic diagram illustrating the feature extraction of the medullary absorption coefficient of corn stalks;

[0052] Figure 16 A schematic diagram illustrating the feature extraction of the cortical absorption coefficient of corn stalks;

[0053] Figure 17 This is a schematic diagram of light transport distribution in a corn stalk cortex-medullary-cortex model.

[0054] Figure 18 This is a schematic diagram of the light transmission distribution in a single layer of medulla.

[0055] Figure 19 A schematic diagram of cortical light transmission distribution under the assumption of an infinite half-plane;

[0056] Figure 20 This is a schematic diagram of the structure of the light source transmitter and the first light source receiver.

[0057] Reference numerals: 1. Clamping mechanism; 2. Light source emitting head; 3. First light source receiving head; 4. Second light source receiving head; 5. Handle; 6. Button; 7. Constant current and switching control chip; 8. Heat sink; 9. Integrated LED light source; 10. Reflector; 11. Convex lens; 12. Photodiode; 13. Filter. Detailed Implementation

[0058] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0059] like Figure 6 As shown, the present invention provides a method for in-situ detection of moisture in corn stalks, comprising:

[0060] Step 1: Select the area of ​​corn stalk to be tested and pre-treat its surface;

[0061] Step 2: Using a corn stalk moisture in-situ detection device, perform contact scanning on the test area of ​​the corn stalk to obtain the absorption coefficient of the corn stalk.

[0062] Step 3: Correlate the absorption coefficient of corn stalks with the corresponding moisture content to determine the moisture content of the corn stalks.

[0063] In step 1, the area to be tested on the corn stalks is selected, specifically as follows:

[0064] Select corn stalks with a diameter greater than 15mm, and define the area to be measured as a semi-cylinder extending 6mm vertically upwards and downwards from the point light source as the center.

[0065] In step 1, the surface of the corn stalk to be tested is pretreated, specifically as follows:

[0066] Remove interfering factors from the surface of the test area of ​​the corn stalk, including withered, yellowish-brown or blackish-brown leaf sheaths and water droplets on the surface of the corn stalk.

[0067] In step 2, the corn stalk moisture in-situ detection device is used to perform contact scanning on the test area of ​​the corn stalk to obtain the absorption coefficient of the corn stalk. Specifically:

[0068] The in-situ moisture detection device for corn stalks uses both reflective and semi-transmittance optical paths to perform contact scanning on the test area of ​​the corn stalks, thereby retrieving the absorption coefficients of the cortex and medulla of the corn stalks.

[0069] The contact scanning uses characteristic wavelengths of 850nm and 950nm, with a wavelength resolution of no less than 20nm. The detection range of a single scan of the characteristic light is fixed, the diffusion radius of the characteristic light is approximately 6mm, and the penetration depth is approximately 5mm. (See schematic diagram below.) Figure 1 As shown.

[0070] In step 3, the relationship between the absorption coefficient of corn stalks and the corresponding moisture content is established to calculate the moisture content of the corn stalks. Specifically:

[0071] The relationship between the absorption coefficients of corn stalk cortex and medulla and the corresponding moisture content of corn stalks is as follows:

[0072] (1)

[0073] (2)

[0074] In the formula, The moisture content of the cortex is expressed as (%). Water content of medulla (%) Absorption coefficient (mm) measured at a wavelength of 950 nm -1 ), Absorption coefficient (mm) measured at 850 nm wavelength -1 );

[0075] The moisture content of corn stalks, calculated based on the cortical and medullary moisture contents, is as follows:

[0076] (3)

[0077] In the formula, The moisture content of the straw is (%).

[0078] like Figure 3a and Figure 3bAs shown, the present invention also provides a corn stalk moisture in-situ detection device, applied to the above-mentioned corn stalk moisture in-situ detection method, including: a detection head, a handle 5, a clamping mechanism 1 and a control module. The clamping mechanism 1 is disposed on the handle 5, and the detection head and the control module are disposed on the clamping mechanism 1. The detection head is connected to the control module. The handle 5 controls the clamping mechanism 1 to insert the corn stalk into its interior, and performs in-situ moisture detection based on the detection head.

[0079] The handle 5 uses a spring mechanism to drive the clamping mechanism 1 to reciprocate, forming a clamping area with the detection head to hold the corn stalks into the device. It is equipped with a pressure sensing element to correlate the spring stress with the stalk diameter. The handle 5 has multiple buttons 6 for different functions, specifically as follows: Figure 2 As shown.

[0080] like Figure 3a and Figure 3b and Figure 20 As shown, the detection head includes a light source emitting head 2, a first light source receiving head 3, and a second light source receiving head 4. The light source emitting head 2 is disposed inside the clamping mechanism 1, and the first light source receiving head 3 is disposed below the light source emitting head 2. The two are collinear in the vertical direction. The second light source receiving head 4 is also disposed inside the clamping mechanism 1, and the second light source receiving head 4 forms a 45° angle with the first light source receiving head 3 on the horizontal plane. The first light source receiving head 3 is used to collect reflected light, and the second light source receiving head 4 is used to collect semi-transparent light. The light source emitting head 2, the first light source receiving head 3, and the second light source receiving head 4 are connected to the control module.

[0081] The light source emitting head 2 consists of an integrated LED light source 9, a heat sink 8, a convex lens 11, and a reflector 10. The light source uses a constant current and switching control chip 7 to ensure a stable light signal. The first light source receiving head 3 and the second light source receiving head 4 are both composed of a photodiode 12 and a filter 13, used to acquire signal light with a resolution of not less than 20nm. A thrust spring is located behind both light source receiving heads to further adapt to changes in straw diameter and surface curvature. A schematic diagram of the structure of the light source emitting head 2 and the first light source receiving head is shown below. Figure 20 As shown, the constant current and switching control chip 7 is part of the control module.

[0082] like Figure 4 and Figure 5 As shown, the control module includes a signal acquisition module, a signal conditioning module, and a data storage and analysis module, which are set on the main control circuit board. The control module controls the acquisition of signals from the sensing elements; controls the conditioning of signals into parameters such as reflectivity, transmittance, and straw diameter for inversion of absorption coefficient and calculation of moisture content; controls the display screen to show the results; and controls the data storage.

[0083] When conducting tests based on the corn stalk moisture in-situ detection device, it is also necessary to perform reference calibration after the device is turned on. A custom PTFE / black rubber round rod is used as a reference rod. The reference button of the device is pressed to obtain the white reference and dark reference in the current state of the device. Preferably, the reference should be recalibrated after each restart or 20 minutes of continuous operation.

[0084] Next, the present invention will provide a detailed description of the above-described apparatus and method in conjunction with specific embodiments:

[0085] Example 1: Measurement of Optical Properties of Corn Stalks

[0086] For the size and structure of corn stalks, an optical property measurement device based on a single integrating sphere is used. The measurement parameters and settings involved in the optical property inversion are as follows:

[0087] Beam diameter: 6.2 mm; Sample thickness: 1-5 mm; Slide thickness: 1 mm; Sample refractive index: medulla 1.3337, cortex 1.3344; Slide refractive index: 1.5.

[0088] Integrating sphere diameter: 80mm; Entrance port diameter: 15mm; Sample port diameter: 15mm; Detector port diameter: 3.2mm; Integrating sphere inner wall reflectance: 98%.

[0089] Optical property measurements were performed on 120 straw samples, determining that the absorption coefficient of the straw tissue layer mainly ranged from 0.02 to 0.6 mm⁻¹. Based on the MATLAB 2024a platform, an adaptive competitive downsampling-partial least squares regression algorithm was used to extract the characteristic wavelength of 950 nm for moisture content, with 850 nm used as the baseline reference band. The medulla R₀... 2 Reaching 0.8535, cortical R 2 Reached 0.7068;

[0090] The transmission of characteristic light in the radial multilayer tissue of corn stalks was analyzed based on MCX (Monte Carlo eXtreme). The parameters involved in the MCX simulation were set as follows, and the parameters concerning the optical properties of the stalk tissue were taken as the average values ​​of the sample set:

[0091] Voxel grid size [170, 170, 170]; voxel length unit 0.1 mm; number of seeds 164,833,5518; total number of photons 10 7 Integration time 100ms; illumination type Gaussian; boundary conditions follow Fresnel reflection; output is set as luminous flux, and the detector photon data is retained.

[0092] Analysis of the photon seed count and photon trajectories revealed that, in a semi-transparent optical path with a light source-detector angle of 45°, the light source emitted a total of 3,749,308 photons in a 100ms integration time, and the detector detected 74,163 photons, representing 1.97% of the total emitted photons. The proportion of photons with an emission angle greater than 120° from the detector was 42.04%.

[0093] The characteristic light reaches 99% light energy attenuation after traveling about 8 mm in a single layer of medulla, while in a multi-layered cortex-medullary-cortex tissue, the characteristic light needs to travel about 5 mm to reach 99% light energy attenuation. Among them, 70% light energy is attenuated after penetrating the first layer of cortex.

[0094] The characteristic light has difficulty penetrating the leaf sheath layer effectively, and it has difficulty penetrating the whole corn stalk. Diffuse reflection, semi-transmission and other detection light paths should be considered.

[0095] This invention provides a dataset of maize straw medullary spectra, such as... Figure 7 As shown, the corn stalk medulla spectral transmission dataset is as follows: Figure 8 As shown, the corn stalk cortical reflectance spectrum dataset is as follows: Figure 9 As shown, the corn stalk cortex transmission spectrum dataset is as follows: Figure 10 As shown, the absorption coefficient of corn straw medulla is as follows: Figure 11 As shown, the absorption coefficient of corn stalk cortex is as follows: Figure 12 As shown, the sampling of the medullary absorption coefficient of corn stalks is as follows: Figure 13 As shown, the sampling of the absorption coefficient of corn stalk cortex is as follows: Figure 14 As shown, the feature extraction of the medullary absorption coefficient of corn stalks is as follows: Figure 15 As shown, the feature extraction of the absorption coefficient of corn stalk cortex is as follows: Figure 16 As shown, the light transmission distribution diagram of the corn stalk cortex-medullary-cortex model is as follows: Figure 17 As shown, the light transmission distribution of a single layer of medulla is as follows: Figure 18 As shown, the cortical optical transmission distribution under the infinite half-plane assumption is as follows: Figure 19 As shown.

[0096] Example 2: In-situ Moisture Detection Device for Corn Stalks

[0097] The light source emitter 2 consists of an integrated LED light source 9, a heat sink 8, a convex lens 11, and a reflector 10. The integrated LED light source 9 uses a custom light-emitting chip to provide 850nm and 950nm detection light and 588nm signal light. The three wavelengths of light are converged and collimated by the reflector 10 and the convex lens 11 and emitted from the light source emitter 2. The heat sink 8 at the rear of the integrated LED light source 9 is used for heat dissipation. The LED constant current driver chip BP1360 is equipped with CD4051 for controlling the light source.

[0098] The photodiode 12 of the light source receiver head is a BPW34S, used to respond to both 850nm and 950nm light, and equipped with two types of filters 13: BP850-10K and BP950-10K. Light source receiver head A and light source emitter head 2 are collinear along the vertical direction and spaced 10mm apart. Light source receiver head B and light source emitter head 2 are at a 45° angle to each other on the horizontal plane. The maximum compressive force of the thrust spring behind light source receiver head B is 20% of the maximum compressive force of the thrust spring behind light source receiver head A.

[0099] The two shells of the handle 5 have human-computer interaction function components embedded on the outside. The handheld shell has a button 6 embedded on the outside, and the non-handheld shell has a device status indicator and an OLED display. The handheld shell has a Type-C charging port for the power board, and the non-handheld shell has an SD card slot. The handheld shell has a spring mechanism connecting the power board and the clamping button inside, and the non-handheld shell has a main control circuit board inside.

[0100] The main control circuit board (i.e., the control module) mainly includes a signal acquisition module, a signal conditioning module, and a data storage and analysis module. The signal acquisition module controls the LED light source, acquires the current signal from the photodiode 12, and acquires the current signal from the pressure sensing element. The signal conditioning module receives the current signal, converts it into a voltage signal, amplifies it, and then converts the amplified voltage signal into an ADC signal. This signal is then processed by an ARM processor to obtain reflectivity, transmittance, and straw diameter. The data storage and analysis module collects the reflectivity, transmittance, and straw diameter data, inverts it into the absorption coefficient, calls the model to correlate the absorption coefficient and moisture content, transmits the moisture content value to the OLED display, and then stores the optical properties and moisture content on an SD card. (See schematic diagram). Figure 4 As shown.

[0101] The main processes of the inversion algorithm include:

[0102] (1) Initialize optical characteristic parameters such as absorption coefficient;

[0103] (2) The initial values ​​are calculated into reflectance and transmittance by the doubling method;

[0104] (3) Compare the measured reflectance, transmittance and calculated values ​​for error. If the error is greater than the threshold, adjust the optical characteristic parameters. (4) Repeat steps (2) and (3) until the error is less than the set threshold.

[0105] The main control circuit board is set with a clock count for the reference signal. When the clock count reaches 1800s or the device is powered off, the reference signal will be cleared. Before running, the sample scanning program checks whether a reference signal exists. If it does not exist, it will send a "No reference information" message to the OLED display. If it exists, the sample scanning program will run and control the integrated LED light source 9 to light up. The light source lighting duration is set to 1000ms. The photodiode 12 is controlled to collect the light signal 100ms after the light source is lit. The integration duration is set to 100ms, and the average number of times is 5, that is, the single scan duration is about 0.6s. At the same time as the light source is lit for 100ms, the pressure sensor current signal is collected, with an average sampling number of 5 times. At the same time, the "Equipment is measuring samples" status indicator light is lit. The photocurrent signal and pressure current signal are processed by the main control circuit board into reflectivity, transmittance and straw diameter. After receiving the reflectivity, transmittance and sample thickness parameters, the inversion program will invert the absorption coefficient for moisture content prediction and display it on the OLED screen. Then the "Equipment is measuring samples" status indicator light will turn off.

[0106] In the whole corn stalk moisture detection mode, if a reference signal is present, the OLED display will sequentially prompt the scanning of the first, third, and fifth internodes of the corn stalk, and finally integrate the moisture content information of the three parts and the moisture content of the whole stalk, which will be output on the OLED display.

[0107] The calculated output light information of light source receiver A and light source receiver B , The sample diameter D, sensed by the spring force measurement system, is input into the embedded optical property inversion program. The diameter needs to be substituted with the optical path correction coefficient K, which is preferably 0.39, to obtain the sample absorption coefficient. ,pass The cortical and medullary resorption coefficients can be derived from the following equations:

[0108] (4)

[0109] Where D is the measured straw diameter (mm), and K is the optical path correction factor, taken as 0.39. Assuming an ideal cortical thickness, let it be a constant of 1 mm. To retrieve the percentage of light energy remaining after penetrating the cortex, To retrieve the percentage of light energy remaining after penetrating the medulla, Cortical absorption coefficient (mm) -1 ), The medullary absorption coefficient (mm)-1 ).

[0110] The inversion process of cortical and medullary resorption coefficients includes:

[0111] (1) Initialization , , and ;

[0112] (2) Substitute into the equation to calculate the loss function;

[0113] (3) Backpropagate gradients based on the chain rule and update , , and (4) Repeat steps (2) and (3) until the error is less than the set threshold.

[0114] For example, the absorption coefficient inversion for 950nm wavelength light is shown in Table 1:

[0115] Table 1. Absorption coefficient inversion table for 950nm wavelength light

[0116]

[0117] The moisture prediction model uses a multivariate linear equation, and the moisture content detection formula is shown in formula (1) and formula (2).

[0118] The equation for detecting the moisture content of whole corn stalks under the whole stalk moisture detection mode is as follows:

[0119]

[0120] (5)

[0121] in Moisture content at a single point (%) The absorption coefficient (mm) measured at a wavelength of 950 nm for the i-th internode. -1 ), The absorption coefficient (mm) measured at 850 nm wavelength for the i-th internode. -1 ), Let be the diameter (mm) of the i-th segment.

[0122] When the device's remaining battery power is less than 15%, the charging indicator light in the device's status indicator will flash. After plugging in a power source, the charging indicator light will remain constantly lit.

[0123] After the device is turned on, the built-in program will check if the SD card exists. If it does not exist, all data saving functions will be disabled during the device's operation, and the measurement results will only be displayed once on the OLED screen. If it exists, all data saving functions will operate normally during the device's operation, and the measurement results will be saved in the SD card in the table format set by this invention.

[0124] Next, the specific usage process of this device will be explained, including:

[0125] Step 1: Select 7 intact corn stalks from the field, ensuring that the diameter of the stalks to be tested is not less than 15mm;

[0126] Step 2: Locate unaffected areas of about 20mm on the first, third, and fifth internodes of these 7 corn stalks, peel off the withered leaf sheaths, and wipe the surface appropriately with a dry paper towel.

[0127] Step 3: Insert the SD card, toggle the switch button to turn on the device provided in this embodiment, and ensure that the "charging indicator light" does not flash;

[0128] Step four: Calibrate the detection device. Using a custom-made PTFE / black rubber rod as a reference rod, sequentially acquire the white and dark reference signals from light source receivers A and B.

[0129] Step 5: Simultaneously press and hold the white reference button and the dark reference button to enter the whole corn stalk moisture detection mode. Place the stalk sample on the detection site, press the sample button to obtain the sample voltage, and then sample the first, third, and fifth internodes of the whole corn stalk in sequence.

[0130] Step 6: Read the final result, exit the whole corn stalk moisture detection mode, turn off the device, and remove the SD card.

[0131] Verification of the detection results of the measurement method in this embodiment is provided:

[0132] To measure the true moisture content of the samples, the samples were cut into sections, their fresh weight was measured, and they were placed in a 105℃ oven to dry to constant weight. The dry weight was then measured, and the moisture content was calculated. The error between the predicted and actual values ​​of the measurement method was analyzed, as shown in Table 2.

[0133] Table 2. Schematic diagram of the true moisture values ​​of the measured samples

[0134]

[0135] Embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0136] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0137] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0138] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0139] Contents not described in detail in this specification are prior art known to those skilled in the art. It is hereby indicated that the above description is intended to help those skilled in the art understand this invention, but does not limit the scope of protection of this invention. Any equivalent substitutions, modifications, improvements, or simplifications of the above descriptions that do not depart from the essential content of this invention fall within the scope of protection of this invention.

Claims

1. A method for in situ detection of moisture in corn stover, characterized by, include: Step 1: Select the area of ​​corn stalk to be tested and pre-treat its surface; The test area was selected from the corn stalks, specifically: Select corn stalks with a diameter greater than 15mm, and define the area to be measured as a semi-cylinder extending 6mm vertically and horizontally from the point source of the light source. The surface of the corn stalk to be tested is pretreated as follows: Remove interfering factors from the surface of the test area of ​​the corn stalk, including withered, yellowish-brown or blackish-brown leaf sheaths and water droplets on the surface of the corn stalk. Step 2: Using an in-situ moisture detection device for corn stalks, perform contact scanning on the test area of ​​the corn stalks to obtain the absorption coefficient of the corn stalks; specifically: The in-situ moisture detection device for corn stalks uses both reflective and semi-transmittance optical paths to perform contact scanning on the test area of ​​corn stalks, and retrieves the absorption coefficients of the cortex and medulla of the corn stalks. The characteristic wavelengths used for contact scanning are 850nm and 950nm, with a wavelength resolution of not less than 20nm. Step 3: Establish the relationship between the absorption coefficient of corn stalks and their corresponding moisture content to determine the moisture content of the corn stalks; establish the relationship between the absorption coefficients of the corn stalk cortex and medulla and their corresponding moisture content, as follows: （1） （2） wherein Cortex water content, Medulla water content, Absorption coefficient measured at 950 nm wavelength, Absorption coefficient measured at 850 nm wavelength; The moisture content of corn stalks, calculated based on the cortical and medullary moisture contents, is as follows: （3） In the formula, is the moisture content of the straw.

2. The corn straw moisture in-situ detection device is applied to the corn straw moisture in-situ detection method of claim 1, characterized by, include: The device includes a detection head, a handle, a clamping mechanism, and a control module. The clamping mechanism is mounted on the handle, and the detection head and control module are mounted on the clamping mechanism. The detection head is connected to the control module. The handle is used to insert corn stalks into the control module, and the device performs in-situ moisture detection based on the detection head.

3. The corn stalk moisture in-situ detection device according to claim 2, characterized in that, The detection head includes a light source emitting head, a first light source receiving head, and a second light source receiving head. The light source emitting head is disposed inside the clamping mechanism, and the first light source receiving head is disposed below the light source emitting head. The two are collinear in the vertical direction. The second light source receiving head is also disposed inside the clamping mechanism, and the second light source receiving head forms a 45° angle with the first light source receiving head on the horizontal plane. The first light source receiving head is used to collect reflected light, and the second light source receiving head is used to collect semi-transparent light. The light source emitting head, the first light source receiving head, and the second light source receiving head are connected to the control module.

4. The corn stalk moisture in-situ detection device according to claim 3, characterized in that, The light source emitting head is composed of an integrated LED light source, a heat sink, a convex lens, and a reflector. The first light source receiving head and the second light source receiving head are both composed of a photodiode and a filter.

5. The corn stalk moisture in-situ detection device according to claim 4, characterized in that, The control module includes a signal acquisition module, a signal conditioning module, and a data storage and analysis module.

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