Generalized Image Acquisition and Analysis

A Mathematical Model and Calibration Procedure for Galvanometric Laser Scanning Systems

Laser galvanometric scanning systems are commonly used in various fields such as three dimensional scanning, medical imaging, material processing, measurement devices and laser display systems. The systems of such kind suffer from distortions. On top of that they do not have a center of projection, which makes it impossible to use common projector calibration procedures. The paper presents a novel mathematical model to predict the image distortions caused by galvanometric mirror scanning systems. In addition, we describe a calibration procedure for recovering its intrinsic and extrinsic parameters.

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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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