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Micro-capteur optique pour la caractérisation des dépôts de pulvérisation en agriculture

Abstract : The use of phytosanitary products in agriculture raises serious questions given their harmful effects on the environment. Various levers can be considered to help farmers reduce the amount of pesticides they use. One of these levers consists in optimizing spraying yields, and therefore spraying better to spray less. It is in this context that this thesis work has been carried out. It aims at proving the feasibility of optical micro-sensors based on RIB waveguides, which will eventually allow a reliable and fast measurement of the spraying of inputs on the leaves of plants, so that it can be optimized. It is based on the hypothesis that the guidance through RIB waveguides will be modified following the deposition of droplets on their surface, via the absorption of part of the evanescent wave.RIB waveguides based on chalcogenide thin films whose design has been optimized by simulation have been realized. Their response to the deposition of water droplets (main constituent of pesticides) was then studied. Experiments carried out at wavelength = 1.55 µm, where the water absorption coefficient is 50 cm-1, confirmed the initial hypothesis. The deposition of droplets on the surface of a guide does indeed lead to a decrease in transmitted light intensity, a decrease all the more important as the volume and the number of drops are important, results in agreement with the simulations. Other experiments carried out between 1 and 2 µm allowed to study the spectral response at the output of the guide, and to observe again the effects of water droplet deposition, with the appearance of absorption bands characteristic of water at 1.45 and 1.9 µm. A multivariate analysis also allowed to establish a predictive model, allowing to go back to the volume of the deposited drops, with a precision of 0.36 µl.These initial results prove the feasibility of optical micro-sensors for droplet detection and make them a potential solution to help farmers optimize their spraying processes.
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Submitted on : Wednesday, March 3, 2021 - 10:06:38 AM
Last modification on : Thursday, March 4, 2021 - 3:28:59 AM


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  • HAL Id : tel-03157349, version 1



Anis Taleb Bendiab. Micro-capteur optique pour la caractérisation des dépôts de pulvérisation en agriculture. Autre. Université Montpellier, 2020. Français. ⟨NNT : 2020MONTG030⟩. ⟨tel-03157349⟩



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