Title: On the Development of a Volumetric Velocimetry Technique Using Multiple Plenoptic Cameras
Speaker: Timothy W. Fahringer, Jr. – Auburn University
Date: Tuesday, June 27, 2017
Time: 10:00 A.M EDT
Location: NASA LaRC Bldg 1200, Rm 227
Sponsors: Dr. Paul Danehy, NASA/LaRC
Abstract: Due to the three-dimensional nature of turbulent flow fields a huge effort has been made to develop three-dimensional (3D), three-component (3C) measurement techniques. One such technique being developed is plenoptic-PIV: a measurement technique based on light field imaging. At the core of this technique is the use of the plenoptic camera, which is capable of recording the spatial and angular information of light rays entering the camera. With this unique information, 3D particle fields can be reconstructed and processed using cross-correlation algorithms yielding a 3D/3C vector field. Since an individual camera can capture angular information this technique can be applied using one or multiple plenoptic cameras. Previous work has focused on the single camera configuration whose main advantage is its single aperture operation allowing for the technique to be applied in facilities with limited optical axis. The main drawback of this technique is that the accuracy in the third-dimension, along the optical axis, is significantly worse than the other two dimensions. This work aims to fix this drawback with the addition of a second plenoptic camera in a stereo-like configuration. With the addition of the second camera the elongation of the particle reconstructions is shown to be removed which results in better quality reconstructions and therefore higher fidelity vector fields. This presentation will explain the imaging process of the plenoptic camera, the particle reconstruction, and volumetric calibration algorithms used to generate the particle reconstructions. In addition, a preliminary experiment will be presented illustrating the capabilities of the technique in an experimental setting.
Bio: Tim Fahringer is currently a PhD candidate at Auburn University, with an expected graduation date of later this summer. In late July he will be joining NIA as a Research Engineer and working with Dr. Paul Danehy at NASA Langley.