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Application of structured illumination for multiple scattering suppression in planar laser imaging of dense sprays.

Berrocal, Edouard LU ; Kristensson, Elias LU ; Richter, Mattias LU ; Linne, Mark LU and Aldén, Marcus LU (2008) In Optics Express 16(22). p.17870-17881
Abstract
A novel approach to reduce the multiple light scattering contribution in planar laser images of atomizing sprays is reported. This new technique, named Structured Laser Illumination Planar Imaging (SLIPI), has been demonstrated in the dense region of a hollow-cone water spray generated in ambient air at 50 bars injection pressure. The idea is based on using an incident laser sheet which is spatially modulated along the vertical direction. By properly shifting the spatial phase of the modulation and using post-processing of the successive recorded images, the blurring effects from multiple light scattering can be mitigated. Since hollow-cone sprays have a known inner structure in the central region, the efficiency of the method could be... (More)
A novel approach to reduce the multiple light scattering contribution in planar laser images of atomizing sprays is reported. This new technique, named Structured Laser Illumination Planar Imaging (SLIPI), has been demonstrated in the dense region of a hollow-cone water spray generated in ambient air at 50 bars injection pressure. The idea is based on using an incident laser sheet which is spatially modulated along the vertical direction. By properly shifting the spatial phase of the modulation and using post-processing of the successive recorded images, the blurring effects from multiple light scattering can be mitigated. Since hollow-cone sprays have a known inner structure in the central region, the efficiency of the method could be evaluated. We demonstrate, for the case of averaged images, that an unwanted contribution of 44% of the detected light intensity can be removed. The suppression of this diffuse light enables an increase from 55% to 80% in image contrast. Such an improvement allows a more accurate description of the near-field region and of the spray interior. The possibility of extracting instantaneous flow motion is also shown, here, for a dilute flow of water droplets. These results indicate promising applications of the technique to denser two-phase flows such as air-blast atomizer and diesel sprays. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Optics Express
volume
16
issue
22
pages
17870 - 17881
publisher
OSA
external identifiers
  • wos:000260865900075
  • pmid:18958069
  • scopus:55349147352
ISSN
1094-4087
DOI
10.1364/OE.16.017870
language
English
LU publication?
yes
id
53341071-e378-45e7-b518-a317bdd19365 (old id 1261851)
date added to LUP
2008-11-25 16:53:59
date last changed
2017-10-22 04:16:11
@article{53341071-e378-45e7-b518-a317bdd19365,
  abstract     = {A novel approach to reduce the multiple light scattering contribution in planar laser images of atomizing sprays is reported. This new technique, named Structured Laser Illumination Planar Imaging (SLIPI), has been demonstrated in the dense region of a hollow-cone water spray generated in ambient air at 50 bars injection pressure. The idea is based on using an incident laser sheet which is spatially modulated along the vertical direction. By properly shifting the spatial phase of the modulation and using post-processing of the successive recorded images, the blurring effects from multiple light scattering can be mitigated. Since hollow-cone sprays have a known inner structure in the central region, the efficiency of the method could be evaluated. We demonstrate, for the case of averaged images, that an unwanted contribution of 44% of the detected light intensity can be removed. The suppression of this diffuse light enables an increase from 55% to 80% in image contrast. Such an improvement allows a more accurate description of the near-field region and of the spray interior. The possibility of extracting instantaneous flow motion is also shown, here, for a dilute flow of water droplets. These results indicate promising applications of the technique to denser two-phase flows such as air-blast atomizer and diesel sprays.},
  author       = {Berrocal, Edouard and Kristensson, Elias and Richter, Mattias and Linne, Mark and Aldén, Marcus},
  issn         = {1094-4087},
  language     = {eng},
  number       = {22},
  pages        = {17870--17881},
  publisher    = {OSA},
  series       = {Optics Express},
  title        = {Application of structured illumination for multiple scattering suppression in planar laser imaging of dense sprays.},
  url          = {http://dx.doi.org/10.1364/OE.16.017870},
  volume       = {16},
  year         = {2008},
}