Generalized Image Acquisition and Analysis

Dynamic Display of BRDFs

This paper deals with the challenge of physically displaying reflectance, i.e., the appearance of a surface and its variation with the observer position and the illuminating environment. This is commonly described by the bidirectional reflectance distribution function (BRDF). We provide a catalogue of criteria for the display of BRDFs, and sketch a few orthogonal approaches to solving the problem in an optically passive way. Our specific implementation is based on a liquid surface, on which we excite waves in order to achieve a varying degree of anisotropic roughness. The resulting probability density function of the surface normal is shown to follow a Gaussian distribution similar to most established BRDF models.

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On Plenoptic Multiplexing and Reconstruction

Gordon Wetzstein, Ivo Ihrke, Wolfgang Heidrich
In: International Journal of Computer Vision (IJCV).



Abstract

Photography has been striving to capture an ever increasing amount of visual information in a single image. Digital sensors, however, are limited to recording a small subset of the desired information at each pixel. A common approach to overcoming the limitations of sensing hardware is the optical multiplexing of high-dimensional data into a photograph. While this is a well-studied topic for imaging with color filter arrays, we develop a mathematical framework that generalizes multiplexed imaging to all dimensions of the plenoptic function. This framework unifies a wide variety of existing approaches to analyze and reconstruct multiplexed data in either the spatial or the frequency domain. We demonstrate many practical applications of our framework including high-quality light field reconstruction, the first comparative noise analysis of light field attenuation masks, and an analysis of aliasing in multiplexing applications.
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Bibtex

@article{Wetzstein:PlenopticMultiplexing:2012,
title={{On Plenoptic Multiplexing and Reconstruction}},
author={Gordon Wetzstein and Ivo Ihrke and Wolfgang Heidrich},
year={2013},
volume = 101,
number = 2,
year = {2013},
pages = {384--400},
}
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