Convolution mixture of FBF and modulated FBF and application to HRTEM images

International audienceIn this paper, we propose a mixture involving a fractional Brownian field and a modulated version of such a field for modeling High Resolution Transmission Electron Microscopy (HRTEM) textures. The mixture under consideration is defined from the convolution operator applied on spatial variables of the two fields under consideration. We present estimation methods for the parameters of the model (2 Hurst parameters and 2 spectral poles) based on Wavelet Packet (WP) spectrum. The relevance of our method is highlighted by its application to the analysis of HRTEM images with active phases of a catalyst.Dans cet article, nous proposons de modéliser certaines textures apparaissant dans les images à Haute Résolution de Microscopie Electronique en Transmission (HRMET) à l'aide d'un mélange composé d'un champ Brownien fractionnaire avec une version modulée d'un tel champ. Le mélange en question est basé sur un opérateur de convolution s'appliquant sur les variables spatiales des deux champs considérés. Nous présentons deux méthodes d'estimation des paramètres de Hurst du modèle en utilisant une approche par ondelettes. Nous présentons également une méthode pour localiser les pôles du modèle. Nous montrons la pertinence de ce modèle en l'appliquant à l'analyse des images HRMET contenant des phases actives d'un catalyseur. Abstract-In this paper, we propose a mixture involving a fractional Brownian field and a modulated version of such a field for modeling High Resolution Transmission Electron Microscopy (HRTEM) textures. The mixture under consideration is defined from the convolution operator applied on spatial variables of the two fields under consideration. We present estimation methods for the parameters of the model (2 Hurst parameters and 2 spectral poles) based on Wavelet Packet (WP) spectrum. The relevance of our method is highlighted by its application to the analysis of HRTEM images with active phases of a catalyst

ARFBF MODEL FOR NON STATIONARY RANDOM FIELDS AND APPLICATION IN HRTEM IMAGES

International audienceThis paper presents a new model called Autoregressive Fractional Brownian Field (ARFBF) for analyzing textures which contain stationary and non-stationary components. The paper also proposes two estimation methods for the parameter of an isotropic fractional Brownian field based on Wavelet Packet (WP) spectrum: the Log-Regression on Diagonal WP spectrum (Log-RDWP) and the Log-Regression on Polar representation of WP spectrum (Log-RPWP). The Log-RPWP method provides a better estimation performance for small size images. We show the interest of ARFBF model and Log-RPWP for characterizing High-Resolution Transmission Electron Microscopy (HRTEM) images

Extensions de Champs Browniens Fractionnaires et Analyse Spectrale Morphologique pour la Discrimination des Catalyseurs

The thesis concerns statistical characterization of spatial arrangements of fringes (active phases) in the catalysts imaged by High Resolution Transmission Electron Microscopy (HRTEM). The contributions proposed in this thesis are two statistical models for the description of these HRTEM image contents. The first model involves 2-D Fractional Brownian Field (FBF) and 2-D Auto Regressive (AR) models, as well as morphological analysis of the spectra associated with these models (ARFBF morphological analysis). Concerning FBF modeling, we propose two methods for estimating its parameter: Log-RDWP (Log-Regression on Diagonal Wavelet Packet spectrum) and Log-RPWP (Log-Regression on Polar representation of Wavelet Packet spectrum). We propose a morphological method on ARFBF spectrum for detecting and identifying HRTEM texture features. It is shown that the morphological properties of spectral features make possible, a separation between different catalysts. The second model proposed in this thesis is a generalization of FBF (GFBF) constructed by using convolution and modulation operators of several FBF. The textures synthesized from GFBF model are shown to present some structural similarities with certain fringe structures present in HRTEM images. We details association of a GFBF to an HRTEM fringe by considering a GFBF mixture comprising an FBF and a modulated version of FBF (model called CMFBF). This CMFBF has a spectral representation associated with two poles (spectral peaks) and two Hurst parameters. The spectral peak at zero frequency characterizes the background of the HRTEM image and the first Hurst parameter describes the regularity of this background. The second peak and its corresponding Hurst parameter is representative of the fringe structural and spectral contents.L'objectif principale de cette thèse est la réalisation de modèles statistiques pour l'analyse et la caractérisation des images observées à Haute Résolution par Microscopie Electronique en Transmission (imagerie HRMET) à nano échelles. L'application visée est la caractérisation des arrangements spatiaux de phases actives dans les catalyseurs afin de comprendre les propriétés de ces matériaux. Les contributions de cette thèse sont la proposition de deux modèles statistiques, deux méthodes d'estimation du paramètre de Hurst et leur application aux images HRMET.Le premier chapitre présente le contexte, la motivation et les contributions principales réalisées dans cette thèse.Le chapitre 2 décrit principalement la modalité d'imagerie utilisée. Il est constitué de 4 sections. La section 1 présente la microscopie électronique en transmission en rappelant les principes physiques et les contraintes de préparations des échantillons. La section 2 présente un premier ensemble d'échantillons d'images HRMET de nanostructures de particules de suie, produites par la combustion incomplète de carburants dans les moteurs diesel. La section 3 présente un deuxième ensemble d'échantillons d'images HRMET des phases actives de catalyseurs d'hydrotraitement. Toutes les images HRMET présentées dans ce travail sont produites à IFP Energies nouvelles, section Physique et Analyse, avec un microscope JEOL 2100F. Ces deux types d'images (suie et catalyseur) seront par la suite analysées et/ou synthétisées par les modèles et méthodes d'estimation proposés. La dernière section présente la relation entre la morphologie des phases actives des catalyseurs et leur observations dans le domaine spatial et fréquentiel.Le chapitre 3 présente une étude bibliographique sur les modèles stochastiques. Pour commencer, nous rappelons les définitions et les propriétés des processus aléatoires à mémoire courte, à mémoire longue et auto-similaires.Le chapitre 4 est consacré à la présentation des modèles et des méthodes d'estimation du paramètres de Hurst proposés qui constituent les contribution en modélisation stochastique de cette thèse.Le chapitre 5 concerne les applications des modèles et méthodes d'estimation proposés aux images HRMET. Il s'agit d'une part importante du travail dans cette thèse et représente la partie appliquée des contributions. Le chapitre 6 termine cette thèse par une conclusion qui résume les contributions et propose quelques pistes d'investigation à partir des modèles stochastiques proposés

Non-stationary texture synthesis from random field modeling

International audienceThe paper presents a generalized non-stationary and fractional model for texture synthesis. The model is based on convolutions and modulation operations of fractional Brownian fields and its associated spectral representation contains many poles with unit norm. Synthesized textures generated from this model can exhibit several non-trivial fringes which can be visualized in natural textures such those involved in high resolution transmission electron microscopy

ARFBF morphological analysis - Application to the discrimination of catalyst active phases

International audienceThis paper addresses the characterization of spatial arrangements of fringes in catalysts imaged by High Resolution Transmission Electron Microscopy (HRTEM). It presents a statistical model-based approach for analyzing these fringes. The proposed approach involves Fractional Brownian Field (FBF) and 2-D AutoRegressive (AR) modeling, as well as morphological analysis. The originality of the approach consists in identifying the image background as an FBF, subtracting this background, modeling the residual by 2-D AR so as to capture fringe information and, finally, discriminating catalysts from fringe characterizations obtained by morphological analysis. The overall analysis is called ARFBF (Auto-Regressive Fractional Brownian Field) based morphology characterization

Screening of insecticides against the mulberry fruit gall midge

In recent years, a kind of mulberry pests which were known as the mulberry gall midge Cotarina sp. in different mulberry planting areas occurred popularly in China. This study aims to screening high efficacy and low toxicity insecticides for controlling Cotarina sp.. The current study can help understand integrated pest management (IPM) of Cotarina sp. by scientific and reasonable insecticide use. Field experiment was carried out to investigate eight insecticides, treated with 3 concentration gradients. The result shows that Imidacloprid, Thiamethoxam, Cyromazine, Bifenthrin and Cypermethrin·Profenofos had high control effect on the mulberry gall midge.Their pesticide residues were all less than Chinese Standard GB2763-2016, which means that they were feasible to control this pest. This paper shows that, to control Cotarina sp. in fruit mulberry production, 10% Imidacloprid WP with 2000~3000 dilution and 25% Thiamethoxam WDG with 1500~2500 dilution and 80% Cyromazine WDG with 1500~2000 dilution are the best. 2.5% Bifenthrin EW with 1000~1500 dilution and 440g/l Cypermethrin·Profenofos EC with 1000~2000 dilution should be used by selection. However, Bifenthrin or Cypermethrin·Profenofos cannot be used in mulberry field for both fruits and leaves, so as to avoid causing silkworm poisoning

Screening of Effective Insecticides Against

In recent years, with the rapid development of the sericulture industry, the pests of mulberry trees are also increasing. Diaghania pyloalis Walker is one of the main pests of mulberry trees, has strong fecundity and very large food intake, especially in Sichuan and Chongqing areas. In order to find out the insecticides which can effectively control D. pyloalis, the screening test of high-efficiency control efficacy was carried out. In the summer of 2020, the 3rd instar larvae of D. pyloalis were selected as the test objects, and the indoor bioassay of 10 insecticides on D. pyloalis was carried out, and the results of the indoor bioassay were tested by field experiments in the autumn. The results show that 2000 times liquid of Dursban, Spinetoram, Chlorantraniliprole, and 1000 times liquid of Dichlorvos and Phoxim had the best control effect on D. pyloalis. Secondly, 2000 times liquid of Imidacloprid and Chlorfenapyr had the better control effect on D. pyloalis. Finally 2000 times liquid of Pymetrozine and Cyromazine had poor control effect, and 1000 times liquid of Azadirachtin had the worst control effect on D. pyloalis. To control D. pyloalis, 2000 dilution of Dursban and Spinetoram, and 1000 times liquid of Dichlorvos can be used in sericultural production. When using Chlorantraniliprole to control D. pyloalis, the leaves of mulberry should be picked with long interval to avoid affecting the quality of cocoons, and it is not recommended to use Cyromazine, Azadirachtin to control D. pyloalis