Nombre total de résultats : 509
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A novel correlation filter based on variational calculus

Djemel Ziou, Dayron Rizo Rodriguez, Nafaa Nacereddine, Salvatore Tabbone  (2019)

Correlation filters have been a popular technique for tackling image classification problems. The traditionalcriteria used to design correlation filters overlook some properties that can improve their discriminative power.Therefore, new criteria are proposed to design a novel correlation filter. Such criteria take advantage ofnegative samples, spatial information and the smoothness of the correlation output space. A closed formis derived from the criteria proposed using variational calculus. Moreover, it is shown that the resultingcorrelation filter is a bandpass filter. Experiments are conducted for face identification under illuminationvariation for a single training image per subject and head pose classification. The correlation filter proposeddelivers favorable scores when compared to other correlation filters and state-of-the-art approaches Voir les détails

Mots clés : Correlation filter, Variational calculus, Face identification, Illumination variation, Single training image, Pose classification

Scale space Radon transform

Djemel Ziou, Nafaa Nacereddine, Aicha Baya Goumeidane  (2021)

An extension of Radon transform by using a measure function capturing the user need isproposed. The new transform, called scale space Radon transform, is devoted to the casewhere the embedded shape in the image is not ?liform. A case study is brought on a straightline and an ellipse where the SSRT behaviour in the scale space and in the presence of noiseis deeply analyzed. In order to show the effectiveness of the proposed transform, the exper-iments have been carried out, ?rst, on linear and elliptical structures generated syntheticallysubjected to strong altering conditions such blur and noise and then on structures imagesissued from real-world applications such as road traf?c, satellite imagery and weld X-rayimaging. Comparisons in terms of detection accuracy and computational time with well-known transforms and recent work dedicated to this purpose are conducted, where theproposed transform shows an outstanding performance in detecting the above-mentionedstructures and targeting accurately their spatial locations even in low-quality images. Voir les détails

Mots clés : radon transform, line, ellipse, scale space, noise

Tool combination for the description of steel surface image and defect classification

Zoheir MENTOURI, Hakim DOGHMANE, Kaddour Gherfi, Rachid Zaghdoudi, Hocine Bourouba  (2021)
Article de conférence

In industry, the automatic recognition of surface defects of flat steel products still represents a real challenge. Indeed, in addition to constraints such as the image noise or blur, there is neither an agreed standard of these defects nor a standard method that can ensure the defect identification, whatever are their size, shape, orientation and location. Thus, the complexity of the algorithm that deals with this matter always depends on specific needs of the application. In this paper, we give details on an approach that combines Gabor wavelets (GW) and the local phase quantization technique (LPQ), to describe the steel surface images, and uses the histogram to extract their characteristics. The defect classification is carried out by means of two classifiers, namely the nearest neighbors and the support vector machine. The method assessment is based on testing different parameter values of the used tools. The approach shows a good performance in terms of recognition rates and feature vector length, which impacts the computing time. Also, the study reveals its suitability for an online steel surface defect recognition application. Voir les détails

Mots clés : Quality control, Computer vision, metal surface imaging, Filter bank application, pattern analysis and recognition

Surface Flaw Classification Based on Dual Cross Pattern

Zoheir MENTOURI, Hakim DOGHMANE, Abdelkrim Moussaoui, Djalil BOUDJEHEM  (2020)
Article de conférence

The evaluation of flat steel surface quality is mainly concerned with detecting and identifying product surface defects. Although the variety of the implemented techniques, this type of control still presents a challenge. In this paper, we assess the Dual Cross Pattern technique, as a feature descriptor, that should be quite discriminative, to ease the steel surface defect classification. The histograms extracted from the captured DCP features are concatenated to represent the global image feature vector. The procedure parameters, as the DCP circle radius, the number of the training images and their choice, are considered to show their impact on the results. The experiment conducted on the NEU published defect database shows that, compared to the other used techniques, the proposed approach reveals not only interesting recognition rates but presents advantages in time coast too. Voir les détails

Mots clés : Image description, pattern recognition, Product quality, steel surface defects, hot rolling process

Steel Strip Surface Defect Identi?cation using MultiresolutionBinarized Image Features

Zoheir MENTOURI, Abdelkrim Moussaou, Djalil BOUDJEHEM, Hakim DOGHMANE  (2020)

The shaped steel strip, in the hot rolling process,may exhibit some surface ?aws. Their origin could bethe internal discontinuities in the input product or thethermomechanical transformation of the material, duringthe shaping process. Such defects are of a random occurrenceand may lead to costly rework operations or to adowngrading of the ?nal product. So, they should bedetected and identi?ed as soon as possible, to allow atimely decision-making. For such a quality monitoring, theused vision systems are mainly based on an imagedescription and a reliable classi?cation. In this paper, weexplore pre-de?ned image ?lters and work on a procedureto extract a discriminant image feature, while realizing thebest trade-off between the improved recognition rate of thesurface defects and the computing time. The proposedmethod is a multiresolution approach, based on theBinarized Statistical Image Features method, employed todate in biometrics. The ?lters, pre-learnt from naturalimages, are applied to steel defect images as a new surfacestructure indicator. They provide a quite discriminating image description. A relevant data reduction is used togetherwith a classi?er to allow an ef?cient recognition rate ofthe defective hot rolled products. Voir les détails

Mots clés : Computer vision, statistical features, Classi?cation, strip surface defects, hot rolling process

Improved cross pattern approach for steel surface defect recognition

Zoheir MENTOURI, Hakim DOGHMANE, Abdelkrim Moussaoui, Hocine Bourouba  (2020)

In steel-making processes, different methods are used for online surface product monitoring. Such a control has become anecessity to avoid additional costs resulting from the poor quality of the final product. With the reported performance that variesfrom one application to another, all the applied methods have to meet a minimum of criteria as accuracy and speed. Thiseffectiveness is assured thanks to a relevant image description and efficient defect classification algorithms. The Dual CrossPattern technique, successfully applied in face recognition, is a concept that relies on coding pixels to provide such a discriminatingdescription of the image. Its principle can perfectly be used in industrial vision applications for surface defect recognition.In this study, the relevance of this method of describing defect images is evaluated, and improvements are proposed to increase itsefficiency. The experimental study shows that the pixel coding that considers the variations of the intensity in several directionsand captures the information from more than one pixel-neighborhood level makes it possible to better detect the variability in thedefect image and helps to increase the defect recognition rate. The experiments are carried out with the use of the publishedNortheastern University (NEU) database for the comparison and with a new constructed database to better show the improvementsbrought by the proposed approach. Voir les détails

Mots clés : Computer vision, Image description, Surface defect classification, Steel process

Modeling and Simulation of Biaxial Strained P-MOSFETs: Application to a Single and Dual Channel Heterostructure

Amine Mohammed TABERKIT, Ahlam GUEN-BOUAZZA, Benyounes Bouazza  (2018)

The objectives of this work are focused on the application of strained silicon on MOSFET transistor. To do this, the impact and benefits obtained with the use of strained silicon technology on p-channel MOSFETs are presented. This research attempt to create conventional and two-strained silicon MOSFETsfabricated from the use of TCAD, which is a simulation tool from Silvaco. In our research, two-dimensional simulation of conventional MOSFET, biaxial strained PMOSFET, and dual-channel strained P-MOSFET has been achieved to extract their characteristics. ATHENA and ATLAS have been used to simulate the process and validate the electronic characteristics. Our results allow showing improvements obtained by comparing the three structures and their characteristics. The maximum of carrier mobility improvement is achieved with the percentage of 35.29 % and 70.59 % respectively, by result an improvement in drive current with the percentage of 36.54 % and 236.71 %, and reduction of leakage current with the percentage of 59.45 % and 82.75 %, the threshold voltage is also enhanced with the percentage of 60 % and 61.4%. Our simulation results highlight the importance of incorporating strain technology MOSFET transistors. Voir les détails

Mots clés : Biaxial strain, CMOS technology, SILVACO-TCAD, Strained silicon layers

The importance of using dual-channel heterostructure in strained P-MOSFETs

Amine Mohammed TABERKIT, Ahlam GUEN-BOUAZZA, Mohamed HORCH  (2018)
Article de conférence

We present in this work a dual-channel heterostructure strained structure, introduce the high carrier mobility Awaited in heterostructure devices while using several models which are: CVT, SHIRAHATA, and WATT, we present a two-dimensional simulation of dual strained channel heterostructure P-MOSFETs. This study is accomplished usingSILVACO-TCAD simulation software, the comparison of the effect of using strain technique on P-MOSFET transistors will demonstrate the importance of using strain technique especially in dual channel heterostructure MOSFET. The simulation of fabrication steps and the extraction of the electronic proprieties in terms of transfer and output characteristics, transconductance, and the quasi-static capacitance allow understanding and interpreting these enhancements Voir les détails

Mots clés : Strained Silicon, SiGe layer, MOSFET; Heterostructure, simulation, Silvaco

Génération d’un réseau sur puce au format VHDL RTL à partir d’unemodélisation de haut niveau UML par raffinement

BOUGUETTAYA Abdelmalek (2017)
Thèse de doctorat

Dans le passé, les systèmes embarqués et numériques ont été confinés surtout aux systèmesinformatiques. Aujourd'hui, ces systèmes sont appliqués dans un grand nombre de domaines etd’appareils tels que les télévisions numériques, les systèmes de communication, les radars, lessystèmes militaires et les instrumentations médicales. L’un des plus grands challenges au niveaude la conception de ces systèmes est l’interconnexion entre ses différents modules. Les réseauxsur puce (NoC) constituent un nouveau paradigme d’interconnexion pour les systèmes sur puce(SoC). Ils ont été proposés comme une solution prometteuse pour résoudre les problèmesrencontrés au niveau des interconnexions classiques.L’augmentation de la taille du réseau provoque plusieurs inconvénients, comme laréduction au niveau de la bande passante et la fréquence de fonctionnement et une augmentationau niveau de la latence et la consommation de l’énergie. Dans le présent document, nousprésenterons une nouvelle approche appliquée pour les réseaux sur puce (topologie Mesh 2D)afin de résoudre les problèmes rencontrés dans les architectures classiques. Cette approche estbasée sur une combinaison entre une stratégie de placement des modules, un routage XY à deuxniveaux et une technique de clustering basée sur la charge de communication entre les modules.Afin d’accélérer la conception de cette structure, nous avons utilisé une approche despécification orientées modèles à base de l’Ingénierie Dirigée par les Modèles (IDM). Nousavons utilisé le paquetage RSM pour modéliser la topologie Mesh 2D à base de cluster et lepaquetage à machine d’état ou encore le paquetage d’activité pour la modélisation de l'algorithmede routage XY à deux niveau (intra-cluster et inter-cluster). Voir les détails

Mots clés : Réseaux sur puce, Algorithme de routage dynamique, Clustering, Topologie Mesh, Systèmes sur puce

Etude, conception et simulation numérique d’un transistor MOSFET biaxial contraint

TABERKIT Mohammed Amine (2018)
Thèse de doctorat

Due to the high need for faster electronic devices, with smaller size and higher performances, Researchers and manufacturers of Semiconductor devices make many efforts to face the difficulties and challenges to improve the performances of these semiconductor devices. One of the solutions consists of applying strained silicon on the conventional devices, in such a way that the structure of the MOSFET transistor on a massive substrate known as conventional does not change completely; however, its performances improve. In order to increase the mobility and speed of these electronic devices, Researchers are facing problems related mainly to the reduction in the size of the devices; these problems are known as short channel effects. The aim of this work is to conduct research allowing the study and the computer-aided design of an enhanced architecture of MOSFET transistors called a biaxial transistor using the SILVACO-TCAD process and device simulation software. The results obtained, allowed us then to determine the performances of this device and to compare them to those of the conventional transistor, to show the importance of the introduction of biaxial strain in the improvement of the carrier’s mobility and the devices speed, thus allowing obtaining better performances while continuing the scaling. Voir les détails

Mots clés : Biaxial, Biaxial strain, High-K material, Mobility, MOSFET, SILVACO-TCAD, simulation, Strained Silicon