Development of a 3-D Fluid Velocimetry Technique based on Light Field Imaging
Type of Degreethesis
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A novel method for performing 3-D particle image velocimetry is developed and demonstrated. The technique is based on light field photography, which uses a dense lenslet array mounted near a camera sensor to simultaneously sample the spatial and angular distribution of light entering the camera. Computational algorithms are then used to refocus the image after it is taken and render a 3-D intensity distribution. This thesis provides an introduction to the concepts of light field photography and outlines the processing steps and algorithms required to obtain a 3-D velocity field. To support this, a ray-tracing simulator is used to simulate light field images and rendering codes are generated to form 3-D particle volumes which can be used for particle image velocimetry (PIV) interrogation. The simulation and rendering code is tested with uniform displacement fields and a spherical vortex, and measurement errors are quantified. It is shown that light field imaging is a feasible method for performing 3-D velocimetry with a single camera, and steps are outlined for further development and testing.