Electronique
The Measure of the Length of the Slabs by Artificial Vision
This work consists in automate the measurement of the length of the slabs in the continuous casting machine in a steel mill. This automation will be done by an artificial vision system that implements a camera matrix and embedded vision software. First, we have to make a rigorous selection of attributes such as the margin of the field of vision, the distance between the camera and the slab, the geometric landmarks of the measure, the detection landmark of the arrival of the slab and the optical reference landmark for measure. We also established a relationship between the real length of an object and the number of pixels occupied by its image after a serie of precise tests in order to integrate it in the measure program. The measuring principle is divided into two steps: First, we make a segmentation of each image with a program developed in this sense which aims to differentiate between the slab and the roller train by reading the brightness of each pixel of the acquired image. This segmentation uses the histogram of gray levels of the slab and the roller table which were obtained after the analysis of their images in their real lighting conditions. Then, the slab is measured with another developed program which calculates the abscissa of the detection landmark of the arrival of the slab, tests the value of the gray level of the pixel of this abscissa, gives a decision signal to blowtorches, then retest the value of gray level of the same abscissa to detect the end of the slab and wait the arrival of the next slab. Both programs operate in a loop until the end of the cut of all of the slabs. At each new cutting plane of the slabs we introduce new data according to the customer's command. A study was necessary to establish a criterion for detecting the slab because the value of one pixel can not be a reference and so we chose the reading of 15 points of twenty and this criterion has yielded concrete and reliable results. A simulation with the camera matrix TVC500 and the image processing map PIP was realized in the process laboratory with success and all programs were developed with the C language. On the ground, it will require ensure a stable lighting within the cut area and a good braking system of the carriage or consider a second camera for measuring the lag of the carriage because it represents the origin landmark and thus adjust the measure. Our work will allow a better measure reliability, the possibility of its exploitation for the optimization of the cut and also the improvement of working conditions of the workers. Voir les détails
Mots clés : Artificial vision, pixel, histogram, real time, image, gray level.
Ultra-wideband CPW Antenna Integrated with Narrow Band Dielectric Resonator
In this paper, an ultra-wideband (UWB) patch antenna integrated with dielectric resonator is proposed for cognitive radio applications. The patch antenna is fed by coplanar waveguide (CPW) line, consists of a rectangular monopole having an elliptical base, and operates from 2.6 to 12 GHz. The proposed structure integrates a narrow band rectangular dielectric resonator antenna (RDRA) for operation. The RDRA operates at 5.8 GHz and is excited through an aperture inserted in the UWB patch antenna that is considered as a ground plane. The electromagnetic analysis is carried out using CST microwave studio and HFSS software. The numerical results, obtained from simulation, are given and compared in terms of S parameters and radiation patterns. Voir les détails
Mots clés : Integrated antenna, coplanar waveguide (CPW) line, rectangular dielectric resonator antenna (RDRA)
EMPIRICAL MODE DECOMPOSITION BASED SUPPORT VECTOR MACHINES FOR MICROEMBOLI CLASSIFICATION
The classification of circulating microemboli, in the bloodstream, as gaseous or particulate matter is vital for selecting appropriate treatment for patients. Until now, Doppler techniques have shown some limitations to determine clearly the nature of circulating microemboli. The traditional techniques are largely based on the Fourier analysis. In this paper we present new emboli detection method based on Empirical mode decomposition and support vector machine using Radio Frequency (RF) signal instead of Doppler signals. Voir les détails
Mots clés : classification, Microemboli, Radio Frequency signals, Empirical Mode Decomposition, ultrasound.
Photovoltaic array modeling and MPPT using artificial neural network.
The good operation of a photovoltaic system depends on weather conditions such as illumination and temperature, because for example in a mobile station powered by a photovoltaic source, power supplied by the photovoltaic generator fluctuates when changing direction or during passage in poorly sunny, In other words, a good photovoltaic system is where the power delivered by the photovoltaic generator is maximum whatever the conditions. In the present work, we will precede first time modeling of solar cells by neural networks, then, we will use this approach to track the point of maximum power regardless of the location of use and operating conditions.; ; ; ; . Voir les détails
Mots clés : signal diode model, modeling, photovoltaic array, Neural Network, MPPT
Local and Global Statistics-Based Explicit ActiveContour for Weld Defect Extraction inRadiographic Inspection
Welding is a process of utmost importance in the metal industry. With the advances in computerscience and artificial intelligence techniques, the opportunity to develop computer aided technique forradiographic inspection in Non-Destructive Testing arose. This paper deals with the weld defects detectionin radiographic films. A greedy active contour model is used exploiting global and local statistics to drivethe model to the boundaries. Moreover, and to decrease the computation cost, the local statisticscomputation is done only for pixels in a selected band. Results seem to be promising ones. Voir les détails
Mots clés : Radiographic inspection, weld defects, Active contours
Analysis of High Tc Superconducting Rectangular Microstrip Patches over Ground Planes with Rectangular Apertures in Substrates Containing Anisotropic Materials
A rigorous full-wave analysis of high superconducting rectangular microstrip patch over ground plane with rectangular aperture in the case where the patch is printed on a uniaxially anisotropic substrate material is presented. The dyadic Green’s functions of the considered structure are efficiently determined in the vector Fourier transform domain. The effect of the superconductivity of the patch is taken into account using the concept of the complex resistive boundary condition. The accuracy of the analysis is tested by comparing the computed results with measurements and previously published data for several anisotropic substrate materials. Numerical results showing variation of the resonant frequency and the quality factor of the superconducting antenna with regard to operating temperature are given. Finally, the effects of uniaxial anisotropy in the substrate on the resonant frequencies of different TM modes of the superconducting microstrip antenna with rectangular aperture in the ground plane are presented. Voir les détails
Mots clés : Anisotropic material, Anisotropic substrates, Dyadic green's functions, Operating temperature, Rectangular aperture, Rectangular microstrip patch, Superconducting microstrip antennas, Uniaxially anisotropic substrate
Resonant Frequency of Tunable Microstrip Ring Antenna Printed on Isotropic or Uniaxially Anisotropic Substrate
In this study, the resonant frequency of annular ring microstrip resonator with uniaxial anisotropic substrate and air gap layer is analyzed. The cavity model for simple ring microstrip antenna is extended with some modifications for the tunable geometry taking into account the anisotropy inthe layer. The theoretical resonant frequency results are in very good agreement with the experimental results reported elsewhere. The air gap tuning effect on the resonant characteristics is also investigated for fundamental and higher order modes. Voir les détails
Mots clés : Microstrip, Ring Antenna
Resonance of High Tc Superconducting Microstrip Patch in a Substrate-Superstrate Configuration
The effect of a protecting dielectric superstrate on the resonance of a high Tc superconducting microstrip patch is investigated. The analysis approach is based on the spectral-domain method of moments in conjunction with the complex resistive boundary condition. The complex surface impedance of the superconducting thin film is determined using London’s equation and the two-fluid model of Gorter and Casimir. Numerical results show that the resonant frequency of the high Tc superconducting rectangular patch decreases monotonically with increasing superstrate thickness, the decrease being greater for high permittivity loading. Voir les détails
Mots clés : Resonance, Microstrip antenna, Superstrate
Fusion-based shape descriptor for weld defect radiographic image retrieval
Content-based image retrieval with relevance feedback plays nowadays an important role in several machine vision applications. In this paper, such a system is proposed for weld radiograms in radiographic testing, with the aim of searching from the overall image database, interactively with the radiograph expert, discontinuities similar to some common weld defect types such as crack, lack of penetration, porosity, and solid inclusion. Therefore, shape features characterizing efficiently these defect indications are required. Two shape descriptors are proposed: a shape geometric descriptor (SGD) consisting of a set of invariant shape geometric measures chosen on the basis of their relationships with the weld defect classes and a generic Fourier descriptor (GFD) known for its discrimination powerfulness for planar filled objects. To improve the weld defect retrieval results, we propose a new fusion-based shape descriptor. The idea of the fusion strategy is to examine the compactness and the rectangularity measures in SGD and derive a criterion permitting the design of a new descriptor f(GFD,SGD) able to better discriminate, particularly, between the problematic defect classes of crack and lack of penetration. Experiments conducted on weld defect image database show the strength of the proposed hybrid descriptor compared to GFD and SGD, simply or hierarchically concatenated or used separately. Voir les détails
Mots clés : Radiographic testing, weld defect, CBIR, SGD, GFD, f(GFD, SGD)
Local Segmentation via an Implicit Region-Based Deformable Model Applied To Weld Defects Extraction
This paper is devoted to present and discuss a model that allows a local segmentation by using statistical information of a given image. It is based on Chan-Vese model, curve evolution, partial differential equations and binary level sets method. The proposed model uses the piecewise constant approximation of Chan-Vese model to compute Signed Pressure Force (SPF) function, this one attracts the curve to the true object(s)’s boundaries. The implemented model is used to extract weld defects from weld radiographic images in the aim to calculate the perimeter and surfaces of those weld defects. Encouraged resultants are obtained on synthetic and real radiographic images. Voir les détails
Mots clés : Active contour, Chan-Vese Model, binary Level set, local segmentation, weld radiographic images