Velocity refinement of PIV using global optical flow
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348_2019_2820_ReferencePDF.pdf
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50aea13fcec17e9366a2df764ce31797
Author(s)
Seong, Jee H
Song, Min S
Nunez, Daniel
Manera, Annalisa
Kim, Eung S
Date Issued
October 29, 2019
Publisher
Springer Berlin Heidelberg
Citation
Experiments in Fluids. 2019 Oct 29;60(11):174
Version
Author's final manuscript
Abstract
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
MIT Department
Massachusetts Institute of Technology. Department of Nuclear Science and Engineering
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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.
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DOI of Published Version
https://doi.org/10.1007/s00348-019-2820-4
