Structured illumination for 3-D Mie imaging and 2-D attenuation measurements in optically dense sprays

Abstract

Qualitative description of spray structure and geometry in the near-field region of atomizing sprays is particularly challenging due to the lack of visibility through such optically dense media. Similarly, quantitative determination of the optical depth can be particularly underestimated as a result of detecting photons which have experienced a number of scattering events. In this paper we demonstrate, based on average imaging, the possibility to reconstruct the “true” 3-D Mie representation of an aerated spray, where image artifacts introduced by multiple scattering have been suppressed by means of Structured Laser Illumination Planar Imaging (SLIPI). Here, six images were used, instead of three usually employed in structured illumination, to reconstruct a single SLIPI image. Based on a similar approach, a 2-D estimation of optical depth has been performed and compared with the conventional single-point attenuation measurement.