Ankara : The Department of Computer Engineering and the Graduate School of Engineering and Science of Bilkent University, 2012.Thesis (Ph. D.) -- Bilkent University, 2012.Includes bibliographical refences.3D computer graphics, with the increasing technological and computational
opportunities, have advanced to very high levels that it is possible to generate very
realistic computer-generated scenes in real-time for games and other interactive
environments. However, we cannot claim that computer graphics research has
reached to its limits. Rendering photo-realistic scenes still cannot be achieved in
real-time; and improving visual quality and decreasing computational costs are
still research areas of great interest.
Recent e orts in computer graphics have been directed towards exploiting
principles of human visual perception to increase visual quality of rendering.
This is natural since in computer graphics, the main source of evaluation is the
judgment of people, which is based on their perception. In this thesis, our aim is
to extend the use of perceptual principles in computer graphics. Our contribution
is two-fold: First, we present several models to determine the visually important,
salient, regions in a 3D scene. Secondly, we contribute to use of de nition of
saliency metrics in computer graphics.
Human visual attention is composed of two components, the rst component
is the stimuli-oriented, bottom-up, visual attention; and the second component
is task-oriented, top-down visual attention. The main di erence between these
components is the role of the user. In the top-down component, viewer's intention
and task a ect perception of the visual scene as opposed to the bottom-up component.
We mostly investigate the bottom-up component where saliency resides.
We de ne saliency computation metrics for two types of graphical contents.
Our rst metric is applicable to 3D mesh models that are possibly animating, and
it extracts saliency values for each vertex of the mesh models. The second metric we propose is applicable to animating objects and nds visually important objects
due to their motion behaviours. In a third model, we present how to adapt the
second metric for the animated 3D meshes.
Along with the metrics of saliency, we also present possible application areas
and a perceptual method to accelerate stereoscopic rendering, which is based on
binocular vision principles and makes use of saliency information in a stereoscopic
rendering scene.
Each of the proposed models are evaluated with formal experiments. The
proposed saliency metrics are evaluated via eye-tracker based experiments and
the computationally salient regions are found to attract more attention in practice
too. For the stereoscopic optimization part, we have performed a detailed
experiment and veri ed our model of optimization.
In conclusion, this thesis extends the use of human visual system principles
in 3D computer graphics, especially in terms of saliency.Bülbül, Muhammed AbdullahPh.D
