Plenoptic Imaging in Particle Tracking Velocimetry Experiments

• Author / Creator

  Hadfield, Jake R

• The aim of this study is to develop a technique capable of performing three-dimensional particle tracking by using images from a plenoptic (or light field) camera. Use of a plenoptic camera enables the collection of three-dimensional positional data within a volume, which would normally require more complex, multi-camera setups. A plenoptic imaging system is simpler to set up, and can be scaled to micro-scale experiments easily. Calibration of the camera is necessary for performing particle tracking, and a major contribution of this work has been developing a Matlab code based on past works to allow for calibration. Two techniques for three-dimensional particle location were developed over the course of this study. One of these relies upon existing commercial software for processing the plenoptic images into refocused images and depth maps. As the commercial software is not specifically aimed at finding particles this approach is inefficient and hard to customize. A second method was developed to overcome these limitations. This method has been named the ETC method after its use of epipolar triangular connections, is capable of extracting 3D particle locations from the raw plenoptic images. Of the two, the refocusing-based approach was determined to be the more accurate method through the interrogation of a toroid vortex in water. To investigate the limitations of the ETC approach, an experimental system for quantifying its uncertainty was developed. A study of a matched-refractive index droplet moving through a slot was also conducted to test the viability of the technique for performing microscale experiments. Based on the results of these experiments, hypotheses regarding the limitations of the ETC approach and recommendations for improving it have been made.

• Subjects / Keywords

  • Calibration
  • Particle Tracking
  • Light Field
  • PTV
  • Microfluidics
  • Plenoptic

• Graduation date

  Spring 2018

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3445HT3S

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.