UBC Theses and Dissertations
Schlieren-based flow imaging Atcheson, Bradley
A transparent medium of inhomogenous refractive index will cause light rays to bend as they pass through it, resulting in a visible distortion of the background. We present a simple 2D imaging method for measuring this distortion and then show how it can be used to visualise gas and liquid flows. Improvements to the existing Background Oriented Schlieren method for acquiring projected density gradients are made by placing a multi-scale wavelet noise pattern behind the flow and measuring distortions using a more reliable optical flow algorithm. Dynamic environment mattes can also be acquired, allowing us to render the flow into novel scenes. Capturing from multiple viewpoints then allows us to tomographically reconstruct 3D models of the temperature distribution of the fluid.
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