  Sensitivity of particle size and shape parameters with respect to digitizationPirard, Eric  ; in Proceedings 13 Int. Congress for Stereology (2011, October) The growing success of image analysis based instruments for particle characterization demonstrates the importance of size and shape analysis in operations involving particulate materials. ISO norms for ... [more ▼] The growing success of image analysis based instruments for particle characterization demonstrates the importance of size and shape analysis in operations involving particulate materials. ISO norms for particle sizing using image analysis are being elaborated to clarify nomenclature and measurement principles. But despite this, there is still a lack of understanding of how the digital representation of a particle affects different size and shape parameters. It is the purpose of this paper to explore the magnitude of estimation errors of a series of size and shape parameters from different digital image representations of a single particle. These images are simulated from grey level images of black particles presenting a Gaussian transition towards their white background. Particles themselves are generated from analytical functions sampled by digital grids with variable densities, positions and orientations. Results of inscribed disk, elongation, circularity, roughness, roundness, etc. are plotted as a function of grid density (magnification) with error bars corresponding to the scattering of results for variable thresholds, grid translations and rotations As a conclusion, confidence intervals are given for parameters as a function of magnification and the most sensitive and robust methods of shape analysis are put forward. [less ▲] Detailed reference viewed: 62 (4 ULg)  Optical analysis of particle size and chromite liberation from pulp samples of a UG2 ore regrinding circuitLeroy, Sophie ; ; Bastin, David et alin Minerals Engineering (2011), 24 Since the early seventies high chromite and low base metal sulphide (BMS) contents of the UG2 reef imposes technological challenges to mineral processors and extractive metallurgists. Forty years later ... [more ▼] Since the early seventies high chromite and low base metal sulphide (BMS) contents of the UG2 reef imposes technological challenges to mineral processors and extractive metallurgists. Forty years later, particle size distribution and size by size mineralogy are considered as key factors to the continuous improvement of the UG-2 ore metallurgy. With the successful development of ultra fine grinding technologies, a compromise has to be found between fine grinding to achieve platinum group minerals liberation and to avoid the overgrinding of gangue minerals, especially chromite gangue which is detrimental in smelting process. Indeed, fine chromite grains, despite of being naturally hydrophobic mineral, can be recovered in flotation concentrate by entrainment. In addition, overgrinding also increase liberation of naturally floatable gangue (talc) which contaminate the concentrate and need to be controlled during flotation. In this paper, innovative techniques of single particle image analysis from both dry and wet samples have been tentatively used to assess the chromite particle size distribution and the chromite grade of samples taken from a secondary milling circuit. Preliminary results demonstrate excellent potential for online particle imaging making use of both the particle geometry (size, shape) and the optical properties (translucency). [less ▲] Detailed reference viewed: 112 (23 ULg)Influence of particle flatness and elongation on size distributions obtained from laser diffraction, static and dynamic image analysis.Califice, Arnaud ; Michel, Frédéric ; et alin World Congress on Particle Technology (2010, April) Detailed reference viewed: 49 (15 ULg)Accuracy of size distributions obtained from single particle static digital image analysis.; ; Pirard, Eric in Proceedings PARTEC2007 (2007) Detailed reference viewed: 39 (6 ULg)Accuracy of size distributions obtained from single particle static digital image analysisGregoire, Max ; ; Pirard, Eric (2007) Detailed reference viewed: 41 (6 ULg)Computer Assisted Spore Classification based on Ornament Spatial Distribution Analysis – An Application to Emsian Miospores from Saudi Arabia; ; et al Conference (2006) Detailed reference viewed: 47 (1 ULg)Grey level intercepts distributions and grain size estimation; ; Pirard, Eric et alin Proceedings 8th European Congress for Stereology and Image Analysis (2005) Detailed reference viewed: 24 (5 ULg)Robustness of Planar Shape Descriptors of ParticlesPirard, Eric ; in Chung, C.-F. (Ed.) Proceedings Mathematical Geology Congress (2005) Detailed reference viewed: 32 (1 ULg)Marble classification using scale spaces; Pirard, Eric ; in Prykryl, R. (Ed.) Dimension Stone (2004) Detailed reference viewed: 13 (2 ULg) |
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