Generalized Image Acquisition and Analysis

Three-Dimensional Kaleidoscopic Imaging

Three-dimensional kaleidoscopic imaging, a promising alternative for recording multi-view imagery. The main limitation of multi-view reconstruction techniques is the limited number of views that are available from multi-camera systems, especially for dynamic scenes. Our new system is based on imaging an object inside a kaleidoscopic mirror system. We show that this approach can generate a large number of high-quality views well distributed over the hemisphere surrounding the object in a single shot. In comparison to existing multi-view systems, our method offers a number of advantages: it is possible to operate with a single camera, the individual views are perfectly synchronized, and they have the same radiometric and colorimetric properties. We describe the setup both theoretically, and provide methods for a practical implementation. Enabling interfacing to standard multi-view algorithms for further processing is an important goal of our techniques.

Projects

Time-resolved 3D Capture of Non-stationary Gas Flows

Bradley Atcheson, Ivo Ihrke, Wolfgang Heidrich, Art Tevs, Derek Bradley, Marcus Magnor, Hans-Peter Seidel
In: Proceedings of SIGGRAPH Asia 2008.



Abstract

Fluid simulation is one of the most active research areas in computer graphics. However, it remains difficult to obtain measurements of real fluid flows for validation of the simulated data. In this paper, we take a step in the direction of capturing flow data for such purposes. Specifically, we present the first time-resolved Schlieren tomography system for capturing full 3D, non-stationary gas flows on a dense volumetric grid. Schlieren tomography uses 2D ray deflection measurements to reconstruct a time-varying grid of 3D refractive index values, which directly correspond to physical properties of the flow. We derive a new solution for this reconstruction problem that lends itself to efficient algorithms to robustly work with relatively small numbers of cameras. Our physical system is easy to set up, and consists of an array of relatively low cost rolling-shutter camcorders that are synchronized with a new approach. We demonstrate our method with real measurements, and analyze precision with synthetic data for which ground truth information is available.
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Bibtex

@ARTICLE{Atcheson:2008,
author = {Bradley Atcheson and Ivo Ihrke and Wolfgang Heidrich and Art Tevs and Derek Bradley and Marcus Magnor and Hans-Peter Seidel},
title = {Time-resolved 3D Capture of Non-stationary Gas Flows},
journal = {ACM Transactions on Graphics (Proc. SIGGRAPH Asia)},
year = {2008},
volume = {27},
number = {5},
pages = {132},
}
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