Velocity refinement of PIV using global optical flow

Abstract In this study, we propose a method to enhance the particle image velocimetry (PIV) velocity resolution using global optical flow along with image warping. A global optical flow formula proposed by Brox et al. (High accuracy optical flow estimation based on a theory for warp...

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Main Authors: Seong, Jee H, Song, Min S, Nunez, Daniel, Manera, Annalisa, Kim, Eung S
Other Authors: Massachusetts Institute of Technology. Department of Nuclear Science and Engineering
Format: Article
Language:English
Published: Springer Berlin Heidelberg 2021
Online Access:https://hdl.handle.net/1721.1/131407
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author Seong, Jee H
Song, Min S
Nunez, Daniel
Manera, Annalisa
Kim, Eung S
author2 Massachusetts Institute of Technology. Department of Nuclear Science and Engineering
author_facet Massachusetts Institute of Technology. Department of Nuclear Science and Engineering
Seong, Jee H
Song, Min S
Nunez, Daniel
Manera, Annalisa
Kim, Eung S
author_sort Seong, Jee H
collection MIT
description Abstract In this study, we propose a method to enhance the particle image velocimetry (PIV) velocity resolution using global optical flow along with image warping. A global optical flow formula proposed by Brox et al. (High accuracy optical flow estimation based on a theory for warping. In: Proceedings of the 8th European conference on computer vision, vol 4, pp 25–36, 2004) is adopted to compensate the intensity changes of PIV image pairs, which depend on the set-up and synchronization of a laser and a camera. The proposed method is quantitatively evaluated and validated using synthetic particle image pairs generated for Rankine vortices and reference DNS-based velocity data. The proposed method outperforms the conventional PIV method in capturing small scale vortex and turbulent structures due to its enhanced spatial resolution. In addition, the proposed method shows good performance in large displacement fields and varying image intensity whereas optical flow is applicable to small displacement and susceptible to image intensity variation in general. Finally, the proposed method is applied to real PIV particle images of a multiple rectangular jet flow. The results show that the proposed method successfully works out high-resolution fluid mechanical structure and quantities while preserving the conventional PIV results. Graphic abstract
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spelling mit-1721.1/1314072023-03-01T15:17:13Z Velocity refinement of PIV using global optical flow Seong, Jee H Song, Min S Nunez, Daniel Manera, Annalisa Kim, Eung S Massachusetts Institute of Technology. Department of Nuclear Science and Engineering Abstract In this study, we propose a method to enhance the particle image velocimetry (PIV) velocity resolution using global optical flow along with image warping. A global optical flow formula proposed by Brox et al. (High accuracy optical flow estimation based on a theory for warping. In: Proceedings of the 8th European conference on computer vision, vol 4, pp 25–36, 2004) is adopted to compensate the intensity changes of PIV image pairs, which depend on the set-up and synchronization of a laser and a camera. The proposed method is quantitatively evaluated and validated using synthetic particle image pairs generated for Rankine vortices and reference DNS-based velocity data. The proposed method outperforms the conventional PIV method in capturing small scale vortex and turbulent structures due to its enhanced spatial resolution. In addition, the proposed method shows good performance in large displacement fields and varying image intensity whereas optical flow is applicable to small displacement and susceptible to image intensity variation in general. Finally, the proposed method is applied to real PIV particle images of a multiple rectangular jet flow. The results show that the proposed method successfully works out high-resolution fluid mechanical structure and quantities while preserving the conventional PIV results. Graphic abstract 2021-09-20T17:16:56Z 2021-09-20T17:16:56Z 2019-10-29 2020-09-24T20:55:32Z Article http://purl.org/eprint/type/JournalArticle https://hdl.handle.net/1721.1/131407 Experiments in Fluids. 2019 Oct 29;60(11):174 en https://doi.org/10.1007/s00348-019-2820-4 Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. Springer-Verlag GmbH Germany, part of Springer Nature application/pdf Springer Berlin Heidelberg Springer Berlin Heidelberg
spellingShingle Seong, Jee H
Song, Min S
Nunez, Daniel
Manera, Annalisa
Kim, Eung S
Velocity refinement of PIV using global optical flow
title Velocity refinement of PIV using global optical flow
title_full Velocity refinement of PIV using global optical flow
title_fullStr Velocity refinement of PIV using global optical flow
title_full_unstemmed Velocity refinement of PIV using global optical flow
title_short Velocity refinement of PIV using global optical flow
title_sort velocity refinement of piv using global optical flow
url https://hdl.handle.net/1721.1/131407
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