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CN-121978022-A - Non-contact soil humidity detection system and method based on polarization imaging

CN121978022ACN 121978022 ACN121978022 ACN 121978022ACN-121978022-A

Abstract

The invention belongs to the technical field of intelligent perception and agricultural informatization, in particular to a non-contact soil humidity detection system and method based on polarization imaging, which aim to solve the problems that the traditional soil humidity detection method is poor in instantaneity, strong in illumination dependence, and incapable of representing real physical states and moving measurement in a characterization way, and specifically comprise an illumination control unit, a polarization imaging unit connected with the illumination control unit through a data bus, a gesture measuring unit connected with the polarization imaging unit through the data bus, a data processing and analyzing unit connected with the polarization imaging unit and the gesture measuring unit through data buses respectively, and a display and output module connected with the data processing and analyzing unit through the data bus.

Inventors

  • TIAN TIAN
  • LI MINGJUN
  • LI CHUANXIANG
  • Hong Yuanmei

Assignees

  • 安庆师范大学

Dates

Publication Date
20260505
Application Date
20260209

Claims (10)

  1. 1. The non-contact soil humidity detection system based on polarization imaging is characterized in that the illumination control unit (101), a polarization imaging unit (201) connected with the illumination control unit through a data bus, a gesture measurement unit (301) connected with the polarization imaging unit through a data bus, a data processing and analysis unit (401) connected with the polarization imaging unit and the gesture measurement unit through the data bus respectively, and a display and output module (501) connected with the data processing and analysis unit through the data bus; The illumination control unit (101) records the incident light intensity, the incident angle and the incident polarization direction and provides stable illumination under the low light condition; the polarization imaging unit (201) adopts a polarization camera to simultaneously acquire four polarization angle reflection images for calculating polarization degree and polarization angle distribution; The attitude measurement unit (301) is used for recording the attitude angle of the camera and the distance from the ground surface in real time, correcting errors caused by the change of the visual angle, recording the geographical coordinates of the soil humidity measurement, and supporting the subsequent fusion of the soil humidity distribution in a large range; The data processing and analyzing unit (401) is used for image preprocessing, polarization feature extraction, optical reflection modeling, humidity inversion and real-time output of humidity estimation values; the display and output module (501) is used for displaying the humidity distribution map in real time and uploading the result to the supervision platform through a wireless link.
  2. 2. The non-contact soil moisture detection system based on polarization imaging as claimed in claim 1, wherein the polarization imaging unit (201) comprises an adjustable cradle head and a polarization camera with a multichannel polarization synchronous acquisition function.
  3. 3. The non-contact soil moisture detection system based on polarization imaging as set forth in claim 1, wherein the four polarization angles of the polarization camera are set to 0 °, 45 °, 90 °, 135 °, respectively.
  4. 4. The non-contact soil humidity detection system and method based on polarization imaging of claim 1, wherein the polarization camera is arranged on an adjustable tripod head, and the adjustable tripod head is used for precisely controlling an incident angle of the polarization camera.
  5. 5. The non-contact soil moisture detection system based on polarization imaging of claim 1, wherein the illumination control unit (101) comprises a natural light monitoring module and a controllable polarized light source module.
  6. 6. The non-contact soil moisture detection system based on polarization imaging of claim 5, wherein the natural light monitoring module is configured to record the incident light intensity, the incident angle and the polarization direction in real time.
  7. 7. The polarized imaging-based noncontact soil humidity detection system of claim 5 wherein the controllable polarized light source module is configured to automatically adjust the output power and the polarization direction to maintain the stability of the reflected signal.
  8. 8. The non-contact soil humidity detection system based on polarization imaging of claim 1, wherein the polarization camera, the adjustable cradle head and the data processing unit are arranged in the same reference coordinate system for keeping consistency of optical and attitude measurement.
  9. 9. The non-contact soil humidity detection method based on polarization imaging is characterized by comprising the following steps of: Step S31, constructing and collecting a polarization imaging unit, realizing synchronous imaging by utilizing an optical beam splitting or polaroid array, and adding a time sequence after acquiring an image; Step S32, configuration and compensation of the illumination control unit are realized, and illumination conditions under different environments are consistent; Step S33, integrating and correcting the attitude measurement unit, unifying clocks for attitude parameters and distance parameters, calculating geometric errors under different view angles, and ensuring consistency of inversion results; Step S34, constructing a data processing and analyzing unit, and realizing image acquisition, feature extraction, reflection modeling and real-time calculation of humidity inversion; And step S35, displaying and outputting, outputting the calculated humidity distribution result to a display terminal through a communication interface, generating a color thermodynamic diagram and superposing geographic coordinate information.
  10. 10. The method for detecting the non-contact soil humidity based on the polarization imaging according to claim 1, wherein the construction of the data processing and analyzing unit in the step S34 specifically comprises the following steps: step S341, preprocessing an image to ensure that the positions of four channels of pixels are consistent; Step S342, calculating polarization characteristics and calculating polarization degree And polarization angle ; Step S343, optical reflection modeling, fusion of incident angles And the illumination direction, correct the polarized reflectivity; step S344, humidity inversion and result output according to real-time calculation Inversion of pixel level water content And generating a humidity distribution matrix and a statistical image.

Description

Non-contact soil humidity detection system and method based on polarization imaging Technical Field The invention belongs to the technical field of intelligent perception and agricultural informatization, and particularly relates to a non-contact soil humidity detection system and method based on polarization imaging. Background Soil humidity is an important basic parameter in the fields of agricultural management, hydrologic regulation, ecological monitoring, geological disaster early warning and the like, and the spatial distribution and dynamic change of the soil humidity directly influence crop growth, water resource scheduling, foundation stability and water circulation of an ecological system. The method for acquiring the high-precision and real-time soil surface layer humidity information is an important precondition for realizing accurate irrigation, intelligent agricultural machinery operation planning and road foundation safety monitoring, and currently, the main soil humidity detection means adopted in the industry comprise a contact sensor method, a remote sensing/spectrum inversion method and a thermal infrared imaging method. The touch sensor method is the most mature technology applied at present, and representative devices comprise a time domain reflectometer, a frequency domain reflectometer and a resistance type water content sensor. The equipment is used for indirectly calculating the water content by inserting a probe into soil to measure the dielectric constant or the resistivity of the equipment, and the method has higher precision in a laboratory or a fixed monitoring point, but has the problems of difficult arrangement, easy corrosion or damage of the probe, high maintenance cost, limited space coverage and the like in a large-area or mobile detection scene, and is difficult to meet the requirements of real-time and dynamic monitoring. The remote sensing or spectrum inversion method utilizes multispectral or hyperspectral sensors carried by platforms such as satellites and unmanned aerial vehicles to realize water content inversion by measuring the surface reflectivity and the short wave infrared absorption characteristics, and the method can reflect soil humidity distribution on a regional scale, but the inversion result is easily influenced by factors such as illumination angle, atmospheric scattering, surface roughness, vegetation coverage and the like, so that the measurement accuracy is unstable. The existing researches show that under the condition of different incidence angles, the reflectivity difference of the same land block can exceed 20%, so that obvious humidity estimation deviation is caused, in addition, the spectroscopy mainly reflects the ultra-shallow water state of the soil surface layer, has insufficient response to humidity change below the shallow layer, and cannot reflect the real moisture gradient. The thermal infrared imaging algorithm monitors the surface temperature field by an infrared camera or thermal imager and inverts the humidity distribution based on the thermophysical relationship between the surface temperature and the moisture. Although the method does not need to contact soil and has certain usability at night, the method is easily influenced by external factors such as solar radiation, wind speed, shadow, soil thermal inertia, vegetation coverage and the like, so that inversion results have large fluctuation and high-precision real-time measurement is difficult to realize. Disclosure of Invention The invention aims to solve the problems that the existing traditional soil humidity detection method is poor in instantaneity, strong in illumination dependence, and incapable of representing the real physical state and mobile measurement in a representation manner. In order to solve the problems, the invention provides a non-contact soil humidity detection system and method based on polarization imaging, which is characterized in that the illumination control unit 101, a polarization imaging unit 201 connected with the illumination control unit through a data bus, a gesture measuring unit 301 connected with the polarization imaging unit through a data bus, a data processing and analyzing unit 401 connected with the polarization imaging unit and the gesture measuring unit respectively through the data bus, and a display and output module 501 connected with the data processing and analyzing unit through the data bus; the illumination control unit records the incident light intensity, the incident angle and the incident polarization direction and provides stable illumination under the low light condition; the polarization imaging unit adopts a polarization camera to simultaneously acquire four polarization angle reflection images and is used for calculating the polarization degree and the polarization angle distribution. The attitude measurement unit is used for recording the attitude angle of the camera and the distance from the ground surface in real t