Characterization of Particular-Laden Scattering Media with Polarization Imaging. Application to Fractal Aggregates
Author | : Benoît Gay |
Publisher | : |
Total Pages | : 216 |
Release | : 2010 |
ISBN-10 | : OCLC:800978050 |
ISBN-13 | : |
Rating | : 4/5 (50 Downloads) |
Book excerpt: Non-invasive diagnostic tools are of particular interest to characterize semi-transparent media for many technological and scientific challenges. The idea of the present work is to probe a multiple scattering particle-laden media, from an external source of radiation, analyzing the polarization state 2D lateral spatial distributions of emerging radiation, which form images. The size, the volume fraction and the morphology of the particles which influence on the radiative properties of the medium are investigated. A focus is put on fractal-like aggregates which are of great importance in many areas. An original polarization imaging configuration is designed to reveal multiple scattering effects. Accordingly, both an experimental setup and a comprehensive model are implemented. The latter is a key part to be likely to understand the phenomenon engaged. Indeed to construe the 2D polarization signature, the polarized light transport is modeled using the Stokes formalism. Solving the problem is performed with an original integration method which is a Monte Carlo algorithm, chosen for its specific advantages. Indeed, this model gives rise to the polarization pattern analysis with physical interpretations. The method is applied to calibrated polystyrene aqueous suspensions which can be used in an aggregation process. The question of aggregation process modeling is addressed in terms of requirements to deal with complex morphology with realistic composition (orientation, configuration, and size dispersion averaging). Effects of multiple scattering intra and inter particle are to be taken into consideration. Sensitivity to the aggregation process and to morphological parameters is specifically discussed.