Elimination of unsteady background reflections in PIV images by anisotropic diffusion

Journal Article (2019)
Author(s)

S. Adatrao (TU Delft - Aerodynamics)

A. Sciacchitano (TU Delft - Aerodynamics)

Research Group
Aerodynamics
Copyright
© 2019 S. Adatrao, A. Sciacchitano
DOI related publication
https://doi.org/10.1088/1361-6501/aafca9
More Info
expand_more
Publication Year
2019
Language
English
Copyright
© 2019 S. Adatrao, A. Sciacchitano
Research Group
Aerodynamics
Issue number
3
Volume number
30
Reuse Rights

Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.

Abstract

A novel approach is introduced that allows the elimination of undesired laser light reflections from particle image velocimetry (PIV) images. The approach relies upon anisotropic diffusion of the light intensity, which is used to generate a background image to be subtracted from the original image. The intensity is diffused only along the edges and not across the edges, thus allowing one to preserve, in the background image, the shape of boundaries as laser light reflections on solid surfaces. Due to its ability to produce a background image from a single snapshot, as opposed to most methods that make use of intensity information in time, the technique is particularly suitable for elimination of reflections in PIV images of unsteady models, such as transiting objects, propellers, flapping and pitching wings. The technique is assessed on an experimental test case which considers the flow in front of a propeller, where the laser light reflections on the model's surface preclude accurate determination of the flow velocity. Comparison of the anisotropic diffusion approach with conventional techniques for suppression of light reflections shows the advantages of the former method, especially when reflections need to be removed from individual images.