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Alexia Gobrecht

Alexia Gobrecht

session, year:
2017 2nd


Receiving laboratory:
IQ, UNICAMP, Institute of Chemistry, Campinas

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Mobility project

Bridges between agrophotonics and biophotonics to improve detection of disease symptoms on biological tissues

Near infrared spectroscopy is a very popular technique in proximal sensing in agriculture: it is easy to implement, even outdoors, spectral signatures are sensitive to biological products and prices of devices fit generally to the range accepted by the sector. It is mainly used to characterize chemical contents from the diffusely reflected light. I focus my work on the development of specific architectures of the optical devices in order to optimize the spectral signatures collected from the samples. The main hypothesis is that by enhancing the optical signal quality, following interpretation and calibration will be improved. The other area where real efforts have been made regarding optical instrumentation for near infrared spectroscopy is for biomedical applications. Indeed, today, NIRS is particularly applied to study tissue and fluids, often with the purpose of diagnostic or health monitoring. If parallels can be drawn between biomedical-photonics and agro-photonics, there are fundamental differences in both implementation of the sensors and analysis of the collected spectral data. The objective of this project is to identify and fill some of these gaps by pooling these two approaches. In agriculture, NIRS is used on plant leaves for disease detection caused by pathogens (fungi, virus, or bacteria). On the other hand, in medicine, NIRS is applied on skin tissue to detect, for example, malignant cells or to monitor in-vivo health parameter (blood oximetry for example). Leaves and skin have in common to be layered materials, composed of cells, which are, in both cases causing specific light matter interactions: absorption and scattering. With the aim to detect the presence of symptoms on plants or skins, the questions I would like to answer through this project are (i) what are the common point and specificities of agrophotonics and biophotonics in terms of instrumentation and data processing to detect symptoms on biological tissues (ii) how can agrophotonics and biophotonics feed each other in order to improve their detection capacities).

Biography & research interests

I am research scientist from the French Ministry of Agriculture, graduated (Msc) from Bordeaux Science Agro in 2000. After 6 years of teaching in agricultural high school, I joined a research team of Irstea, the French scientific and technological research institute for agriculture and the environment, member of Agreenium.

For almost 5 years, I was a project engineer. I have beensetting up and running research projects, interfacingbetween the funders, scientific partners of other institutions and researchers of my team. This led me to deal with the whole innovation process: from the emergence of a scientific question to the production of a research result and its transfer to the industrial sector.

With the desire to carry my own research theme, I initiated a thesis in 2011 in the field of instrumentation for the characterization of soils properties by visible and near infrared spectrometry. Since my defence, in 2014, my research focuses on the design of Vis-NIR spectrometric measurement systems to characterize the chemical and physical properties of complex scattering media, mainly in the field of plant sciences (phenotyping, disease detection…) and precision agriculture.

Selected publications

Rey-Bayle, M.; Bendoula, R.; Henrot, S.; Lamiri, K.; Baco-Antoniali, F.; Caillol, N.; Gobrecht, A.; Roger, J.M., 2017. Potential of vis-NIR spectroscopy to monitor the silica precipitation reaction. Analytical and Bioanalytical Chemistry, 409 (3), 785-796.

Gobrecht, A., Bendoula, R., Roger, J.-M., Bellon-Maurel, V., 2016. A new optical method coupling light polarization and Vis-NIR spectroscopy to improve the measured absorbance signal’s quality of soil samples. Soil and Tillage Research, 155, 461-470.

Gobrecht, A., Bendoula, R., Roger, J.-M., Bellon-Maurel, V., 2015. Combining linear polarization spectroscopy and the Representative Layer Theory to measure the Beer-Lambert's Law Absorbance of highly turbid media. Analytica Chimica Acta, 853, 486-494.

Bendoula, R., Gobrecht, A., Moulin, B., Roger, J.-M., Bellon-Maurel, V., 2015. Improvement of the chemical content prediction of a model powder system by reducing multiple scattering using polarized light spectroscopy - Applied Spectroscopy, 69, 95-102.

Gobrecht, A., Roger, J.-M., Bellon-Maurel, V., 2014. Chapter Four - Major Issues of Diffuse Reflectance NIR Spectroscopy in the Specific Context of Soil Carbon Content Estimation: A Review, In: Donald L. Sparks, Editor(s), Advances in Agronomy, Academic Press, Volume 123, Pages 145-17.



Near infrared Spectroscopy, Hyperspectral imaging, Optical Properties, Biological Tissues, Plant leaf, Skin, Disease symptom detection, Biophotonics, Agrophotonics, Chemometrics