Emerging thermal imaging techniques for seed quality evaluation: Principles and applications

Due to the massive progress occurred in the past few decades in imaging, electronics and computer science, infrared thermal imaging technique has witnessed numerous technological advancement and smart applications in non-destructive testing and quality monitoring of different agro-food produces. Thermal imaging offers a potential non-contact imaging modality for the determination of various quality traits based on the infrared radiation emitted from target foods. The technique has been moved from just an exploration method in engineering and astronomy into an effective tool in many fields for forming unambiguous images called thermograms eventuated from the temperature and thermal properties of the target objects. It depends principally on converting the invisible infrared radiation emitted by the objects into visible two-dimensional temperature data without making a direct contact with the examined objects. This method has been widely used for different applications in agriculture and food science and technology with special applications in seed quality assessment. This article provides an overview of thermal imaging theory, briefly describes the fundamentals of the system and explores the recent advances and research works conducted in quality evaluation of different sorts of seeds. The article comprehensively reviewed research efforts of using thermal imaging systems in seed applications including estimation of seed viability, detection of fungal growth and insect infections, detection of seed damage and impurities, seed classification and variety identification.info:eu-repo/semantics/acceptedVersio

Utilisation de nouvelles techniques d'imagerie pour la vision en milieux diffusants

Vision through scattering media is a large problem due to interactions between light and particles composing the medium. If we consider vision through fog, this work analyses two optical techniques : one inspired from optical coherence tomography (OCT) combined with a photo-refractive crystal (PRC) and the other one founded upon micro-laser optical feedback. An analytical model based on Mie's theory is developed for the estimation of the decrease of the signal to noise ratio in a foggy scene. The results highlight the necessity of selecting useful information and eliminating lighty noise during images acquisitions. We demonstrate the high potential of the two imaging techniques both based on the principle of useful signal selection. The OCT-PRC device carries out a coherent temporal selection whereas the optical feedback device does a spatial selection. Results obtained with a disrutive medium are detailed with explanations on the limitations of currents systems and ways of improvements.La vision à travers les milieux diffusants est rendue difficile à cause des interactions entre la lumière et les particules composant le milieu. Dans le cadre de la vision dans le brouillard, ces trvaux de thèse portent sur l'étude de deux techniques optiques : l'une fondée sur la tomographie par cohérence optique (OCT) couplée à un cristal photo-réactif (PCR) et l'autre reposant sur le principe de la rétro-injection dans un micro-laser. Un modèle analytique fondé sur la théorie de Mie est développé pour prédire la décroissance du rapport signal à bruit dans une scène bruitée par du brouillard. L'exploitation des résultats analytique met en avant la nécessité de sélectionner l'information utile et d'éliminer le bruit lumineux lors des prises de vue pour conserver des images correctement contrastées . Nous démontrons le fort potentiel exploitable des deux techniques d'imagerie étudiées puisqu'elles reposent sur le principe de sélection du signal utile. Le montage OCT-PRC réalise une sélection par cohérence temporelle et le montage de rétro-injection laser une sélection spatiale. Les résultats obtenus en présence d'un milieu perturbateur sont détaillés en explicitant les limitations des dispositifs actuels et les voies d'améliorations à entreprendre

Utilisation de nouvelles techniques d'imagerie pour la vision en milieux diffusants

La vision à travers les milieux diffusants est rendue difficile à cause des interactions entre la lumière et les particules composant le milieu. Dans le cadre de la vision dans le brouillard, ces travaux de thèse portent sur l'étude de deux techniques optiques : l'une fondée sur la tomographie par cohérence optique (OCT) couplée à un cristal photo-réactif (PCR) et l'autre reposant sur le principe de la rétro-injection dans un micro-laser. Un modèle analytique fondé sur la théorie de Mie est développé pour prédire la décroissance du rapport signal à bruit dans une scène bruitée par du brouillard. L'exploitation des résultats analytique met en avant la nécessité de sélectionner l'information utile et d'éliminer le bruit lumineux lors des prises de vue pour conserver des images correctement contrastées . Nous démontrons le fort potentiel exploitable des deux techniques d'imagerie étudiées puisqu'elles reposent sur le principe de sélection du signal utile. Le montage OCT-PRC réalise une sélection par cohérence temporelle et le montage de rétro-injection laser une sélection spatiale. Les résultats obtenus en présence d'un milieu perturbateur sont détaillés en explicitant les limitations des dispositifs actuels et les voies d'améliorations à entreprendre.Vision through scattering media is a large problem due to interactions between light and particles composing the medium. If we consider vision through fog, this work analyses two optical techniques : one inspired from optical coherence tomography (OCT) combined with a photo-refractive crystal (PRC) and the other one founded upon micro-laser optical feedback. An analytical model based on Mie's theory is developed for the estimation of the decrease of the signal to noise ratio in a foggy scene. The results highlight the necessity of selecting useful information and eliminating lighty noise during images acquisitions. We demonstrate the high potential of the two imaging techniques both based on the principle of useful signal selection. The OCT-PRC device carries out a coherent temporal selection whereas the optical feedback device does a spatial selection. Results obtained with a disrutive medium are detailed with explanations on the limitations of currents systems and ways of improvements.ANGERS-BU Lettres et Sciences (490072106) / SudocSudocFranceF

Fourier-transform quantum phase estimation with quantum phase noise

International audienc

Quantum signal processing for quantum phase estimation: Fourier transform versus maximum likelihood approaches

International audienc

Détection des pathogènes dans les tissus végétaux : les approches non destructives du projet PHENOTIC

à Angers (France) le 08/11/ 2012Journée sur les technologies numériques et électroniques au service du végétal du pôle de compétitivité Végépoly

An analytical model for backscattered luminance in fog: comparisons with Monte Carlo computations and experimental results

We propose an analytical model for backscattered luminance in fog and derive an expression for the visibility signal-to-noise ratio as a function of meteorological visibility distance. The model uses single scattering processes. It is based on the Mie theory and the geometry of the optical device (emitter and receiver). In particular, we present an overlap function and take the phase function of fog into account. The results of the backscattered luminance obtained with our analytical model are compared to simulations made using the Monte Carlo method based on multiple scattering processes. An excellent agreement is found in that the discrepancy between the results is smaller than the Monte Carlo standard uncertainties. If we take no account of the geometry of the optical device, the results of the model-estimated backscattered luminance differ from the simulations by a factor 20. We also conclude that the signal-to-noise ratio computed with the Monte Carlo method and our analytical model is in good agreement with experimental results since the mean difference between the calculations and experimental measurements is smaller than the experimental uncertainty

5 th IAMPS 2016 Image Analysis Methods for the Plant Sciences

National audienc

Use of Chlorophyll Fluorescence Imaging to phenotype effectors impacts on Nicotiana benthamiana

National audienc

The Temporal Voice Areas are not “just” Speech Areas

International audienceThe Temporal Voice Areas (TVAs) respond more strongly to speech sounds than to non-speech vocal sounds, but does this make them Temporal “Speech” Areas? We provide a perspective on this issue by combining univariate, multivariate, and representational similarity analyses of fMRI activations to a balanced set of speech and non-speech vocal sounds. We find that while speech sounds activate the TVAs more than non-speech vocal sounds, which is likely related to their larger temporal modulations in syllabic rate, they do not appear to activate additional areas nor are they segregated from the non-speech vocal sounds when their higher activation is controlled. It seems safe, then, to continue calling these regions the Temporal Voice Areas