Imaging and 3D Tomographic Reconstruction of Time-varying, Inhomogeneous Refractive Index Fields

We present a technique for 2D imaging and 3D tomographic reconstruction of time-varying, inhomogeneous refractive index fields. Our method can be used to perform three-dimensional reconstruction of phenomena such as gas plumes or liquid mixing. We can also use the 2D imaging results of such time-varying phenomena to render environment mattes and caustics. To achieve these results, we improve a recent fluid imaging technique called Background Oriented Schlieren imaging, and develop a novel theory for tomographic reconstructions from Schlieren images based on first principles of optics. We demonstrate our approach with two different measurement setups, and discuss example applications such as measuring the heat and density distribution in gas flows.