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.


Eikonal Rendering: Efficient Light Transport in Refractive Objects

Ivo Ihrke, Gernot Ziegler, Art Tevs, Christian Theobalt, Marcus Magnor, Hans-Peter Seidel
In: Proceedings of SIGGRAPH 2007.


We present a new method for real-time rendering of sophisticated lighting effects in and around refractive objects. It enables us to realistically display refractive objects with complex material properties, such as arbitrarily varying refraction index, inhomogeneous attenuation, as well as spatially-varying anisotropic scattering and reflectance properties. User-controlled changes of lighting positions only require a few seconds of update time. Our method is based on a set of ordinary differential equations derived from the eikonal equation, the main postulate of geometric optics. This set of equations allows for fast casting of bent light rays with the complexity of a particle tracer. Based on this concept, we also propose an efficient light propagation technique using adaptive wavefront tracing. Efficient GPU implementations for our algorithmic concepts enable us to render visual effects that were previously not reproducible in this combination in real-time.
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author = "I.~Ihrke and G.~Ziegler and A.~Tevs and C.~Theobalt and M.~Magnor and H.-P.~Seidel",
title = "Eikonal Rendering: Efficient Light Transport in Refractive Objects",
journal = "ACM Trans. on Graphics (Siggraph'07)",
year = "2007",
month = aug,
pages="to appear"
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