Generalized Image Acquisition and Analysis

State of the Art in Computational Plenoptic Imaging

The plenoptic function is a ray-based model for light that includes the color spectrum as well as spatial, temporal, and directional variation. Although digital light sensors have greatly evolved in the last years, one fundamental limitation remains: all standard CCD and CMOS sensors integrate over the dimensions of the plenoptic function as they convert photons into electrons; in the process, all visual information is irreversibly lost, except for a two-dimensional, spatially-varying subset - the common photograph. In this state of the art report, we review approaches that optically encode the dimensions of the plenpotic function transcending those captured by traditional photography and reconstruct the recorded information computationally.

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Dynamic Display of BRDFs

Matthias Hullin, Ramesh Raskar, Hans-Peter Seidel, Hendrik P. A. Lensch, Ivo Ihrke
In: Proceedings of EUROGRAPHICS 2011.



Abstract

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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Bibtex

@INPROCEEDINGS{HullinEG2011,
AUTHOR = {Hullin, Matthias B. and Lensch, Hendrik P. A. and Raskar, Ramesh and Seidel, Hans-Peter and Ihrke, Ivo},
EDITOR = {Deussen, Oliver and Chen, Min},
TITLE = {Dynamic Display of {BRDFs}},
BOOKTITLE = {Computer Graphics Forum (Proc. EUROGRAPHICS)},
ORGANIZATION = {Eurographics},
PADDRESS = {Oxford, UK},
ADDRESS = {Llandudno, UK},
PUBLISHER = {Blackwell},
YEAR = {2011},
PAGES = {475--483},
}
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