Benoit de Solan

ARVALIS Institut du végétal · Department of Information Technology

Allometric rules provide insights into the structure-function relationships across species and scales and are commonly used in ecology. The fields of agronomy, plant phenotyping and modeling also need simplifications such as allometric rules to reconcile data at different temporal and spatial levels (organs/canopy). This paper explores the variatio...

This study aimed to provide the first results and lessons of the transfer of the ALPHI® phenotyping tool to potato. The ALPHI® device is a tractor with two arms carrying RGB cameras and spectroradiometers, able to acquire proximal sensing variables on microplot experiments. Originally developed for cereals, its transfer was one of the objectives of...

Monitoring crops with high spatio-temporal resolution satellites provides valuable observations to ensure food security in the global change context. This study focuses on estimating the Green Area Index (GAI) to monitor wheat crops with a spatial resolution of 3 m and daily satellite observations from the SuperDove constellation. With an easier ac...

Data competitions have become a popular approach to crowdsource new data analysis methods for general and specialized data science problems. Data competitions have a rich history in plant phenotyping, and new outdoor field datasets have the potential to embrace solutions across research and commercial applications. We developed the Global Wheat Cha...

Applying deep learning to images of cropping systems provides new knowledge and insights in research and commercial applications. Semantic segmentation or pixel-wise classification, of RGB images acquired at the ground level, into vegetation and background is a critical step in the estimation of several canopy traits. Current state of the art metho...

The sowing pattern has an important impact on light interception efficiency in maize by determining the spatial distribution of leaves within the canopy. Leaves orientation is an important architectural trait determining maize canopies light interception. Previous studies have indicated how maize genotypes may adapt leaves orientation to avoid mutu...

The number of leaves at a given time is important to characterize plant growth and development. In this work, we developed a high-throughput method to count the number of leaves by detecting leaf tips in RGB images. The digital plant phenotyping platform was used to simulate a large and diverse dataset of RGB images and corresponding leaf tip label...

Measuring leaf area is a critical task in plant biology. Meshing techniques, parametric surface modelling and implicit surface modelling allow estimating plant leaf area from acquired 3D point clouds. However, there is currently no consensus on the best approach because of little comparative evaluation. In this paper, we provide evidence about the...

The Global Wheat Head Detection (GWHD) dataset was created in 2020 and has assembled 193,634 labelled wheat heads from 4700 RGB images acquired from various acquisition platforms and 7 countries/institutions. With an associated competition hosted in Kaggle, GWHD_2020 has successfully attracted attention from both the computer vision and agricultura...

The Global Wheat Head Detection (GWHD) dataset was created in 2020 and has assembled 193,634 labelled wheat heads from 4,700 RGB images acquired from various acquisition platforms and 7 countries/institutions. With an associated competition hosted in Kaggle, GWHD has successfully attracted attention from both the computer vision and agricultural sc...

Plants density is a key information on crop growth. Usually done manually, this task can beneficiate from advances in image analysis technics. Automated detection of individual plants in images is a key step to estimate this density. To develop and evaluate dedicated processing technics, high resolution RGB images were acquired from UAVs during sev...

The detection of wheat heads in plant images is an important task for estimating pertinent wheat traits including head population density and head characteristics such as health, size, maturity stage, and the presence of awns. Several studies have developed methods for wheat head detection from high-resolution RGB imagery based on machine learning...

Detection of wheat heads is an important task allowing to estimate pertinent traits including head population density and head characteristics such as sanitary state, size, maturity stage and the presence of awns. Several studies developed methods for wheat head detection from high-resolution RGB imagery. They are based on computer vision and machi...

Nitrogen management poses a major challenge for winter wheat producers in France. The amount of nitrogen input is currently computed with a balance approach, which is estimated at an early stage in the crop season. This approach has been revisited to propose a method based on real-time monitoring of nitrogen nutrition index (NNI) thus triggering th...

Accurate and timely observations of wheat phenology and, particularly, of heading date are instrumental for many scientific and technical domains such as wheat ecophysiology, crop breeding, crop management or precision agriculture. Visual annotation of the heading date in situ is a labour-intensive task that may become prohibitive in scientific and...

Achieving novel improvements in crop management may require changing interrow distance in cultivated fields. Such changes would benefit from a better understanding of plant responses to the spatial heterogeneity in their environment. Our work investigates the architectural plasticity of wheat plants in response to increasing row spacing and evaluat...

In order to evaluate the impact of water deficit in field conditions, researchers or breeders must set up large experiment networks in very restrictive field environments. Experience shows that half of the field trials are not relevant because of climatic conditions that do not allow the stress scenario to be tested. The PhénoField® platform is the...

Total above-ground biomass at harvest and ear density are two important traits that characterize wheat genotypes. Two experiments were carried out in two different sites where several genotypes were grown under contrasted irrigation and nitrogen treatments. A high spatial resolution RGB camera was used to capture the residual stems standing straigh...

Hardware Software Structural traits Leaf traits Dynamics of traits Conclusion High resolution RGB camera + 6000 x 4000 pixels + Pixel size: 3.93 µm + Focal length: 30-60 mm + Weight: 500 g with lens Footprint 4,2mm Footprint 8mm AIRPHEN multispectral camera + 1080 x 960 pixels + 6 configurable bands + Pixel size: 3.04 µm + Focal length: 4.2-8 mm +...

Wheat ear density estimation is an appealing trait for plant breeders. Current manual counting is tedious and inefficient. In this study we investigated the potential of convolutional neural networks (CNNs) to provide accurate ear density using nadir high spatial resolution RGB images. Two different approaches were investigated, either using the Fa...

Phenotyping in breeding trials is the basis for the selection of new varieties of food, feed and fibre crops that support the continued growth of world population. In addition to economic yield, breeders measure many phenotypes (also called traits) associated with the adaptation of these crops, such as the time of flowering, the height of the crop...

ARVALIS - Institut du végétal is a French applied research institute focusing on agronomic studies. Investments in the development of FHTP tools within different research projects (PHENOME/Emphasis-France infrastructure) and partners. A set of research field platforms, in contrasted French locations, are presently equipped with a range of FHTP devi...

Structural 3D plant models aim at mimicking the dynamics of plant and crop structure based on experimental data. Such models can be interfaced with physical models to investigate plant-environment interactions. This work aimed at defining functions that represent the leaf and tiller development of individual wheat plants, and that could be fitted t...

Cette communication fait un état des lieux des connaissances actuelles sur la gestion agronomique des adventicesdes céréales,et analyse les possibilités offertes par les nouvelles technologies. Plusieurs essais de longue durée réalisés par ARVALIS Institut du végétal permettent d’évaluer l’effet des leviers agronomiques (travail du sol, rotation, c...

Ce numéro comprend les articles correspondant aux présentations du Colloque Casdar 2018.

The capacity of LiDAR and Unmanned Aerial Vehicles (UAVs) to provide plant height estimates as a high-throughput plant phenotyping trait was explored. An experiment over wheat genotypes conducted under well watered and water stress modalities was conducted. Frequent LiDAR measurements were performed along the growth cycle using a phénomobile unmann...

This work investigates the spatial distribution of wheat plants and its consequences on the canopy structure. A set of RGB images were taken from nadir on a total 14 plots showing a range of sowing densities, cultivars and environmental conditions. The coordinates of the plants were extracted from RGB images. Results show that the distance between-...

The PHENOMOBILE -LV is a fully automated robot designed for high -precision, high -throughput field phenotyping. It is equipped with several sensors including RGB cameras, spectroradiometers working in the visible and near infrared, and LIDARs. All these measurements are performed from nadir and inclined directions to gather complementary informati...

Context and aims. The 3D structure of plants is an important aspect of plant-interface with the environment, involved in the capture of resources, the exposition to stresses and physical transfers both within the plant and at canopy level. For these reasons describing plants in 3D is an important aspect of functional structural plant modelling. Des...

Optimizing potato Nitrogen (N) Use Efficiency is essential to reach high yield, satisfy market requirements concerning tuber quality criterions and limit Nitrogen losses in water and in the atmosphere. French potato growers could improve their fertilization practices in many ways. Among them, available remote sensing tools are not widely used. Alth...

Digital and image analysis technologies in greenhouses have become commonplace in plant science research and started to move into the plant breeding industry. However, the core of plant breeding work takes place in fields. We will present successive technological developments that have allowed the migration and application of remote sensing approac...

Crop response to abiotic stress is a complex trait, muddled by genotype by environment interactions, and multiple underlying traits. This is typically the case for response to nitrogen in wheat. High throughput phenotyping provides access to intermediate level traits that can help in understanding, screening, and ultimately ameliorating nitrogen re...

Field phenotyping technologies are regularly cited as one of the new frontiers to accelerate genetic progress in plant breeding. Remote sensing specialists regrouped in Avignon, France have led successive research and development projects to create a number of new technological tools that allow canopy traits to be screened on large panels of genoty...

Recent improvements in phenomics have opened up vast opportunities to understand and predict dynamic phenotypic responses to genotypic variation. To date however, a great majority of phenomics studies are conducted in controlled condition facilities, such as growth chambers and greenhouses, in which plants function as individuals. In crop species h...

Introduction : Drought is projected to be an increasing problem for crops in France and evaluating drought tolerance is a complex task. Using rain-out shelters, PhénoField®, the ARVALIS platform of PHENOME project (French Plant Phenotyping Network) can control drought stress condition in field with high capacity for housing large genotype panels. U...

Introduction : Drought is projected to be an increasing problem for wheat in France. We provide some key figures on current and projected drought stress in France. Evaluating drought tolerance is a complex task. Climate variability can lead to very different drought stress conditions in field experiments. The importance of genotype by environment i...

Les capteurs en agriculture

Leaf reflectance of monocotyledons generally displays a strong azimuthal anisotropy due to the longitudinal orientation of the veins. The Cook and Torrance (CT) bidirectional reflectance distribution function model was adapted to account for this distinctive feature. The resulting ACT (Anisotropic Cook and Torrance) model is based on the decomposit...

Keywords: Sorghum Wheat Leaf Surface roughness BRDF BRF Reflectance Conoscope Azimuthal anisotropy Optical properties Goniometer Physical model Refractive index Leaf reflectance of monocotyledons generally displays a strong azimuthal anisotropy due to the longitudinal orientation of the veins. The Cook and Torrance (CT) bidirectional reflectance di...

Wheat crops undergo multiple biotic or abiotic stresses during their development cycle, the main effect of which is a reduction of green leaf area. Preliminary studies showed a stable relationship between Area Under the Green Leaf Area Index (AUGLAI) during the grain filling period and yield. This study aims at establishing a global index character...

La présente invention concerne un dispositif de mesure de la transmission directionnelle de lumière dans un couvert végétal (C), pour la détermination d'un indice de surface dudit couvert végétal (C). Ce dispositif de mesure (1) comprend un support vertical (2) sur lequel sont rapportés des capteurs de rayonnement (3, 4, 5) sont répartis sur au moi...

A semi-automatic system was developed to monitor micro-plots of wheat cultivars in field conditions for phenotyping. The system is based on a hyperspectral radiometer and 2 RGB cameras observing the canopy from similar to 1.5 m distance to the top of the canopy. The system allows measurement from both nadir and oblique views inclined at 57.5 degree...

This study focuses on the directionality of wheat leaf reflectance as a function of leaf surface characteristics. Wheat leaf BRF measurements were completed under 45° zenith illumination angle in three visible broad spectral bands with a conoscope that provides very high angular resolution data over a large portion of the whole hemisphere, includin...

The objective of this study is to evaluate the performances of estimating agronomic variables, such as total above ground biomass at key stages, or yield, from LAI data that could potentially be obtained from remote sensing observations. Approaches based either on empirical relationships or on forcing LAI within the STICS model (Brisson et al., 200...

Accéder plus facilement à des traits phénotypiques plus nombreux et suivre leur dynamique via des approches non destructives s’avère indispensable pour le développement de disciplines telles que l’agronomie, la génétique ou l’écophysiologie. Le couplage entre les progrès générés par ces connaissances disciplinaires (connaissance du génome, biologie...

This study describes a technique to estimate green area index (GAI) of row crops from gap fraction measurements at 57.5° perpendicular to the row using downward looking digital photos. This particular directional configuration makes the gap fraction independent from leaf angle distribution and minimizes leaf clumping when plants overlap within the...

SCANAREA est un logiciel d’analyse de scan d’organes de plantes pour mesurer différents paramètres de plante: • Surface de feuille, de tige ou de fruit (distinction de la partie verte et sénescente) • Paramètres de forme pour chaque feuille : longueur maximum, largeur maximum, largeur = f(distance à l’origine) Le principe repose sur l’utilisation d...

SCANAREA est un logiciel d’analyse de scan d’organes de plantes pour mesurer différents paramètres de plante: • Surface de feuille, de tige ou de fruit (distinction de la partie verte et sénescente) • Paramètres de forme pour chaque feuille : longueur maximum, largeur maximum, largeur = f(distance à l’origine) Le principe repose sur l’utilisation d...

SCANAREA est un logiciel d’analyse de scan d’organes de plantes pour mesurer différents paramètres de plante: • Surface de feuille, de tige ou de fruit (distinction de la partie verte et sénescente) • Paramètres de forme pour chaque feuille : longueur maximum, largeur maximum, largeur = f(distance à l’origine) Le principe repose sur l’utilisation d...

A SVAT calibration methodology based on the optimization of surface brightness temperature has been developed (Coudert et al., 2006a; 2006b, 2007) and validated at field scale in the framework of the Alpilles-ReSeDA ([1]; http://www.avignon.inra.fr/reseda/base/) experiment. This methodology has been extended at regional scale and applied to MSG/Met...

This study is part of the SUDMED project from IRD (Research Institute for Development), CESBIO, University of Marrakech and Moroccan administrations in charge of agriculture, forestry and water management. The objective of this project is the hydro-ecological modeling of hydrological resources on the Marrakech region. In this context, it is importa...

The use of satellite data to monitor the snow contribution to runoff in a small semi-arid mountainous sub-watershed is explored. The Rehraya watershed, 228km2 is located in the Atlas range. Its altitude range from 1068 to 4084m and its hydrological regime is characterized by an important snow contribution. The "soil and water assessment tool" has b...