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P. Kán:
"High-Quality Real-Time Global Illumination in Augmented Reality";
Supervisor, Reviewer: H. Kaufmann, M. Billinghurst, A. Chalmers; Institute of Software Technology and Interactive Systems, 2014; oral examination: 2014-08-22.

High-quality image synthesis, indistinguishable from reality, has been one of the most important
problems in computer graphics from its beginning. Image synthesis in augmented reality
(AR) poses an even more challenging problem, because coherence of virtual and real objects
is required. Especially, visual coherence plays an important role in AR. Visual coherence can
be achieved by calculating global illumination which introduces the light interaction between
virtual and real objects. Correct light interaction provides precise information about spatial
location, radiometric properties, and geometric details of inserted virtual objects. In order to
calculate light interaction accurately, high-quality global illumination is required. However,
high-quality global illumination algorithms have not been suitable for real-time AR due to their
high computational cost. Global illumination in AR can be beneficial in many areas including
automotive or architectural design, medical therapy, rehabilitation, surgery, education, movie
production, and others.
This thesis approaches the problem of visual coherence in augmented reality by adopting the
physically based rendering algorithms and presenting a novel GPU implementation of these algorithms.
The developed rendering algorithms calculate the two solutions of global illumination,
required for rendering in AR, in one pass by using a novel one-pass differential rendering algorithm.
The rendering algorithms, presented in this thesis, are based on GPU ray tracing which
provides high quality results. The developed rendering system computes various visual features
in high quality. These features include depth of field, shadows, specular and diffuse global illumination,
reflections, and refractions. Moreover, numerous improvements of the physically
based rendering algorithms are presented which allow fast and accurate light transport calculation
in AR. Additionally, this thesis presents the differential progressive path tracing algorithm
which can calculate the unbiased AR solution in a progressive fashion.
Finally, the presented methods are compared to the state of the art in real-time global illumination
for AR. The results show that our high-quality global illumination outperforms other
methods in terms of accuracy of the rendered images. Additionally, the human perception of developed
global illumination methods for AR is evaluated. The impact of the presented rendering
algorithms to visual realism and to the sense of presence is studied in this thesis. The results
suggest that high-quality global illumination has a positive impact on the realism and presence
perceived by users in AR. Thus, future AR applications can benefit from the algorithms developed
in this thesis.

http://publik.tuwien.ac.at/files/PubDat_230675.pdf