References of "Pirard, Eric"
     in
Bookmark and Share    
Peer Reviewed
See detailComputer Assisted Spore Classification based on Ornament Spatial Distribution Analysis – An Application to Emsian Miospores from Saudi Arabia
Dislaire, Godefroid; Breuer, Pierre; Filatoff, John et al

Conference (2006)

Detailed reference viewed: 49 (1 ULg)
Full Text
Peer Reviewed
See detailAdvanced particle characterization for improved; understanding of spray coating quality
Pirard, Eric ULg; Campana, Florent; Janssen, Jean-Pierre

in Proceedings International Thermal Spray Conference (2006)

The size and shape of individual particles are essential characteristics to control their behavior during spraying. Thanks to recently available technology in powder image analysis, this paper ... [more ▼]

The size and shape of individual particles are essential characteristics to control their behavior during spraying. Thanks to recently available technology in powder image analysis, this paper investigates the correlation between the geometric properties of several thousands of particles and their flowability (Hall flowmeter) and apparent density (Scott volumeter). Four different chromium carbide Cr3C2-NiCr 75/25 powders used for HVOF wear / oxidation resistant coatings are studied. The coating quality obtained for each powder by the HVOF spraying process is further investigated using metallographic image analysis. [less ▲]

Detailed reference viewed: 8 (1 ULg)
See detailLandslide risk analysis in the Mailuu-Suu valley (Kyrgyzstan) by means of remote sensing techniques
Danneels, Gaelle; Pirard, Eric ULg; Torgoev, Isakbek et al

in Geophysical Research Abstracts (2005)

Detailed reference viewed: 4 (0 ULg)
Full Text
Peer Reviewed
See detailImage processing of 2D resistivity data for imaging faults
Nguyen, Frédéric ULg; Garambois, Stephane; Jongmans, Denis et al

in Journal of Applied Geophysics (2005), 57(4), 260-277

A methodology to locate automatically limits or boundaries between different geological bodies in 2D electrical tomography is proposed, using a crest line extraction process in gradient images, This ... [more ▼]

A methodology to locate automatically limits or boundaries between different geological bodies in 2D electrical tomography is proposed, using a crest line extraction process in gradient images, This method is applied on several synthetic models and on field data set acquired on three experimental sites during the European project PALEOSIS where trenches were dug. The results presented in this work are valid for electrical tomographies data collected with a Wenner-alpha array and computed with an 1(1) norm (blocky inversion) as optimization method, For the synthetic cases. three geometric contexts are modelled: a vertical and a dipping fault juxtaposing two different geological formations and a step-like structure. A superficial layer can cover each geological structure. In these three situations, the method locates the synthetic faults and layer boundaries, and determines fault displacement but with several limitations. The estimated fault positions correlate exactly with the synthetic ones if a conductive (or no superficial) layer overlies the studied structure. When a resistive layer with a thickness of 6 in covers the model, faults are positioned with a maximum error of 1 m. Moreover, when a resistive and/or a thick top layer is present, the resolution significantly decreases for the fault displacement estimation (error up to 150%). The tests with the synthetic models for surveys using the Wenner-alpha array indicate that the proposed methodology is best suited to vertical and horizontal contacts. Application of the methodology to real data sets shows that a lateral resistivity contrast of 1:5 1:10 leads to exact faults location. A fault contact with a resistivity contrast of 1:0.75 and overlaid by a resistive layer with a thickness or 1 m gives an error location ranging from 1 to 3 m. Moreover, no result is obtained for a contact with very low contrasts (similar to 1:0.85) overlaid by a resistive soil. The method shows poor results when vertical gradients are greater than horizontal ones. This kind of image processing technique should be systematically used for improving the objectiveness of tomography interpretation when looking for limits between geological objects. (c) 2005 Elsevier B.V. All rights reserved. [less ▲]

Detailed reference viewed: 172 (26 ULg)
See detailSpreading segregation of bulk blends
Miserque, Olivier; Pirard, Eric ULg; Schenkel, Yves

(2005)

Detailed reference viewed: 16 (3 ULg)
Full Text
See detailFertilizer particles characterization : standard methods and image analysis
Miserque, Olivier; Pirard, Eric ULg; Chapeau, Vincent

in Annual Meeting International Fine Particle Research Institute (2005)

Detailed reference viewed: 21 (0 ULg)
Full Text
Peer Reviewed
See detailGrey level intercepts distributions and grain size estimation
Lebichot, Sophie; Dislaire, Godefroid; Pirard, Eric ULg et al

in Proceedings 8th European Congress for Stereology and Image Analysis (2005)

Detailed reference viewed: 30 (7 ULg)
Full Text
See detail3D particles characterization techniques – a review
Pirard, Eric ULg

in International Fine Particle Research Institute (2005)

Detailed reference viewed: 14 (1 ULg)
Full Text
See detailRobustness of Planar Shape Descriptors of Particles
Pirard, Eric ULg; Dislaire, Godefroid

in Chung, C.-F. (Ed.) Proceedings Mathematical Geology Congress (2005)

Detailed reference viewed: 34 (1 ULg)
Full Text
Peer Reviewed
See detailAdvanced particle characterization for improved understanding of cold spray coating quality
Pirard, Eric ULg; Campana, Florent; Janssen, Jean-Pierre

in Pawlowski, Lech (Ed.) 2e Rencontres Int. Projection Thermique (2005)

Detailed reference viewed: 24 (2 ULg)
Full Text
Peer Reviewed
See detailMultispectral imaging of ore minerals in optical microscopy
Pirard, Eric ULg

in Mineralogical Magazine (2004), 68(2), 323-333

Multispectral imaging of ore minerals under the microscope is a logical extension of quantitative colour analysis and microspectrophotometric analysis of minerals. This paper describes, step by step, how ... [more ▼]

Multispectral imaging of ore minerals under the microscope is a logical extension of quantitative colour analysis and microspectrophotometric analysis of minerals. This paper describes, step by step, how the proper calibration of a scientific video camera can be performed in order to obtain precise reflectance measurements at each pixel within the field of view. After having reviewed the different sources of noise and aberration, practical formulae are presented that allow for the acquisition of a set of images at different wavelengths in the visible spectrum. The advantage of using a multispectral image acquisition system based on narrow bandwidth (10 nm) interference filters is discussed and quantitatively compared to colour imaging using tri-stimulus (red, green, blue) filters. Images taken from major sulphide parageneses are shown as examples of well contrasted multispectral images. Finally, the potential for automatic identification of ore minerals is discussed with reference to supervised multivariate image classification algorithms similar to those used in remote sensing. Additional comments on extending the principles for handling optical anisotropy and developing a multiradial imaging system are made. [less ▲]

Detailed reference viewed: 121 (11 ULg)
Full Text
Peer Reviewed
See detailInfluence of morphological characteristics of heterogeneous moraine formations on their mechanical behaviour using image and statistical analysis
Lebourg, Thomas; Riss, Joelle; Pirard, Eric ULg

in Engineering Geology (2004), 73(1-2), 37-50

The study of landslide stability on mountain slopes becomes more difficult when the sliding materials. are heterogeneous. This is a current problem with the old glacial moraines now under study in the ... [more ▼]

The study of landslide stability on mountain slopes becomes more difficult when the sliding materials. are heterogeneous. This is a current problem with the old glacial moraines now under study in the Aspe Valley, Pyrenees. Analysis of slope stability numerical models necessitates accurate data about mechanical and physical properties. Because moraines are very heterogeneous, a large sample is necessary, but, unfortunately, data acquisition costs a lot of time and money. Therefore, we would like to estimate mechanical properties from correlated variables that are easier to acquire (morphological variables using image analysis). Observations in the field and previous mechanical results in the laboratory have shown that differences between the behaviour of moraines seem to be related not only to their three-dimensional structure but also to the morphological and petrographical characteristics of their components. The moraines are classified based on textural characteristics at the sample scales based on the distributions of size and shape of their constitutive elements (blocks, matrix, etc.). Then, we study the statistical distribution of the variables to highlight the most significant variables. Next, we evaluate the results of the mechanical behaviour of the moraines, with the internal angle of friction and the effective cohesion. On seven specific moraines, we established relations between the effective internal angle of friction, the elongation factor and the roughness factor. (C) 2003 Elsevier B.V. All rights reserved. [less ▲]

Detailed reference viewed: 57 (2 ULg)
Full Text
Peer Reviewed
See detailSegregation of the bulk blend fertilizers
Miserque, Olivier; Pirard, Eric ULg

in Chemometrics and Intelligent Laboratory Systems (2004), 74(1), 215-224

Bulk blend fertilizers are a mixture of different kinds of fertilizers in order to obtain a predicted N-P-K chemical composition. Although this production method has some advantages, segregation appears ... [more ▼]

Bulk blend fertilizers are a mixture of different kinds of fertilizers in order to obtain a predicted N-P-K chemical composition. Although this production method has some advantages, segregation appears at different stages, from the production to the final spreading on the field. An experiment has been implemented to predict and quantify the influence of some physical properties on the occurrence of segregation. The principle was to blend two fertilizers having identical physical properties except for one, such as size, shape or density and to measure the segregation of the blend following various operations, such as filling or emptying a container. Results show that the spread of the fragment size distribution has a big influence on the segregation of the generated heap. In order to reduce this phenomenon, the granulometric spread index (GSI) [(d(84)-d(16))/2d(50)] must be smaller than 10. Other properties don't seem to have an influence. The granulometric segregation can lead to a chemical heterogeneity. The absolute sum of the difference between d(16) and d(84) must be limited around 0.5 mm. Above this value, the chemical segregation begins to be excessive. It seems also that if there is a limited difference in size for the components, the chemical segregation is amplified if the density of the fertilizer with the biggest particles is lower. It is not the case for the difference in shape. (C) 2004 Elsevier B.V. All rights reserved. [less ▲]

Detailed reference viewed: 109 (16 ULg)
Full Text
Peer Reviewed
See detailCartografía de Minerales Evaporiticos Utilizando Imágenes Satelitales de los Salares de Sud Lipez (Bolivia)
Caceres, Fernando; Ali-Ammar, Hamid; Pirard, Eric ULg

in XVI Congreso Geologico Boliviano (2004)

Detailed reference viewed: 93 (1 ULg)
Full Text
Peer Reviewed
See detailMonitoring color alteration of ornamental flagstones using digital image analysis.
Lebrun, Vincent; Toussaint, Caroline; Pirard, Eric ULg

in Prykryl, R. (Ed.) Dimension Stone (2004)

Detailed reference viewed: 20 (1 ULg)
Full Text
See detailCartografia Preliminar de los minerales evaporiticos del salar de Coipasa utilisando imagenes Aster
Caceres, Fernando; Gutierrez, Jorge; Pirard, Eric ULg

in Conferencia Nacional de Valorizacion de los Salares (2004)

Detailed reference viewed: 57 (1 ULg)
Full Text
Peer Reviewed
See detailAnalisis Mineralogico Cuantitativo
Pirard, Eric ULg

in XVI Congreso Geologico Boliviano (2004)

Detailed reference viewed: 19 (0 ULg)
Full Text
Peer Reviewed
See detailMultiradial Image Analysis in Optical Reflected Light Microscopy
Pirard, Eric ULg; Lebichot, Sophie

in XIIIth European Congress for Microscopy (2004)

Detailed reference viewed: 22 (3 ULg)
See detailQuality control of particulate materials through image analysis.
Pirard, Eric ULg

in Optics and Industrial Vision (2004)

Detailed reference viewed: 15 (4 ULg)
Full Text
Peer Reviewed
See detailTélédétection et télégestion des informations géologiques : de nouvelles technologies au service du développement.
Pirard, Eric ULg; Caceres, Fernando

in Bulletin des Séances de l’Académie Royale des Sciences d’Outre-Mer = Mededelingen der Zittingen van de Koninklijke Academie voor Overzeese Wetenschappen (2004), 50(3), 321-348

Detailed reference viewed: 23 (5 ULg)