Generalized Image Acquisition and Analysis

An evaluation of optical flow algorithms for background oriented schlieren imaging

The background oriented schlieren method (BOS) allows for accurate flow measurements with a simple experimental configuration. To estimate per-pixel displacement vectors between two images, BOS systems traditionally borrow window-based algorithms from particle image velocimetry. In this paper, we evaluate the performance of more recent optical flow methods in BOS settings. We also analyze the impact of different background patterns, suggesting the use of a pattern with detail at many scales. Experiments with both synthetic and real datasets show that the performance of BOS systems can be significantly improved through a combination of optical flow algorithms and multiscale background.


A Reconfigurable Camera Add-On for High Dynamic Range, Multispectral, Polarization, and Light-Field Imaging

Alkhazur Manakov, Oliver Klehm, Elmar Eisemann, Hans-Peter Seidel, Ivo Ihrke


We propose a non-permanent add-on that enables plenoptic imaging with standard cameras which we refer to as KaleidoCamera. Our design is based on a physical copying mechanism that multiplies a sensor image into a number of identical copies that still carry the plenoptic information of interest. Via different optical filters, we can then recover the desired information. A minor modification of the design also allows for aperture subsampling and, hence, light-field imaging. As the filters in our design are exchangeable, a reconfiguration for different imaging purposes is possible. We show in a prototype setup that high dynamic range, multispectral, polarization, and light-field imaging can be achieved with our design.
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author = {Alkhazur Manakov and John Restrepo and Oliver Klehm and Ramon Hegeds and Elmar Eisemann and Hans-Peter Seidel and Ivo Ihrke},
title = {A Reconfigurable Camera Add-On for High Dynamic Range, Multispectral, Polarization, and Light-Field Imaging},
journal = {ACM Trans. on Graphics (SIGGRAPH'13)},
volume = 32, number = 4, year = 2013,
pages = {xx--yy},
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