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Please use this identifier to cite or link to this item: http://hdl.handle.net/1942/13893

Title: A Geometric Optics Approach to Simulating Light Wave Phenomena in Computer Graphics
Authors: Cuypers, Tom
Advisors: Bekaert, Philippe
Issue Date: 2012
Abstract: In this work an introduction to the Wigner Distribution function (WDF) is provided using geometric optics principles. The WDF provides a useful model of wave{ elds, allowing simulation of di raction and interference e ects. These Fourier optics concepts are explained to computer graphics researchers by clarifying the relationship between the WDF and position{ angle representations. A novel method for simulating wave e ects in graphics using ray{based renderers is presented with a new function: the Wave BSDF (Bidirectional Scattering Distribution Function). Re ections from neighboring surface patches represented by local BSDFs are mutually independent. However, in many surfaces with wavelength{scale micro structures, interference and di raction requires a joint analysis of re ected wave fronts from neighboring patches. A simple method is demonstrated to compute the BSDF for the entire micro structure, which can be used independently for each patch. This allows using traditional ray{based rendering pipelines to synthesize wave e ects. The Wigner Distribution Function is exploited to create transmissive, re ective, and emissive BSDFs for various di raction phenomena in a physically accurate way. In contrast to previous methods for computing interference, there is no need to explicitly keep track of the phase of wave by using a BSDF that includes positive as well as negative coe cients. These negative values, derived from the WDF allow creating destructive interference; however the rendered result will always end up with non{negative light intensities. The theory is described and compared in relation to well understood concepts in rendering and demonstrate a straightforward implementation. In conjunction with standard ray tracers, such as PBRT, wave e ects are demonstrated for a range of scenarios such as multi{bounce di raction materials, holograms, audio midair di raction and re ection of high frequency surfaces. We demonstrate its e ciency using modern graphics hardware, which allow for real{time rendering and is interesting for rapid prototyping of complex optical constructions. A discussion is provided about its validity in the near{ eld, far{ eld, and under the paraxial approximation. Finally, although the WDF representation contains negative values, an intuition is provided that any projection always yields a non-negative intensity value.
URI: http://hdl.handle.net/1942/13893
Category: T1
Type: Theses and Dissertations
Appears in Collections: Expertise Centre for Digital Media
Expertise Centre for Digital Media

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