Title: “On the Development of a Volumetric Velocimetry Technique Using Multiple Plenoptic Cameras”
Speaker: Timothy Fahringer, PhD Candidate, Auburn University
Date: Friday, February 24, 2017
Time: 10:30 – 11:30
Location: NASA LaRC, Building 1200, Room 227
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 pleonastic-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, 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, work on the theoretical accuracy and the design of a plenoptic system will be presented.
Bio: Tim Fahringer recieved a BAE degree in Aerospace Engineering from Auburn University in 2011 and continued into the Graduate program under Dr. Brian Thurow. For his master’s work he developed the algorithms and computational framework for single camera plenoptic PIV. In 2015 he was awarded a NIFS Internship at NASA Langley under the mentorship of William Humphreys where he worked to access the capabilities that single camera plenoptic PIV could provide to NASA ground test facilities. His PhD work is on the development of a multi camera plenoptic PIV system with an anticipated graduation date of May 2017.