29,936 research outputs found
Visual attention models and applications to 3D computer graphics
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
Algorithmic Perception of Vertices in Sketched Drawings of Polyhedral Shapes
In this article, visual perception principles were used to build an artificial perception model aimed at developing an algorithm for detecting junctions in line drawings of polyhedral objects that are vectorized from hand-drawn sketches. The detection is performed in two dimensions (2D), before any 3D model is available and minimal information about the shape depicted by the sketch is used. The goal of this approach is to not only detect junctions in careful sketches created by skilled engineers and designers but also detect junctions when skilled people draw casually to quickly convey rough ideas. Current approaches for extracting junctions from digital images are mostly incomplete, as they simply merge endpoints that are near each other, thus ignoring the fact that different vertices may be represented by different (but close) junctions and that the endpoints of lines that depict edges that share a common vertex may not necessarily be close to each other, particularly in quickly sketched drawings. We describe and validate a new algorithm that uses these perceptual findings to merge tips of line segments into 2D junctions that are assumed to depict 3D vertices
The Sound Manifesto
Computing practice today depends on visual output to drive almost all user
interaction. Other senses, such as audition, may be totally neglected, or used
tangentially, or used in highly restricted specialized ways. We have excellent
audio rendering through D-A conversion, but we lack rich general facilities for
modeling and manipulating sound comparable in quality and flexibility to
graphics. We need co-ordinated research in several disciplines to improve the
use of sound as an interactive information channel.
Incremental and separate improvements in synthesis, analysis, speech
processing, audiology, acoustics, music, etc. will not alone produce the
radical progress that we seek in sonic practice. We also need to create a new
central topic of study in digital audio research. The new topic will assimilate
the contributions of different disciplines on a common foundation. The key
central concept that we lack is sound as a general-purpose information channel.
We must investigate the structure of this information channel, which is driven
by the co-operative development of auditory perception and physical sound
production. Particular audible encodings, such as speech and music, illuminate
sonic information by example, but they are no more sufficient for a
characterization than typography is sufficient for a characterization of visual
information.Comment: To appear in the conference on Critical Technologies for the Future
of Computing, part of SPIE's International Symposium on Optical Science and
Technology, 30 July to 4 August 2000, San Diego, C
Escaping RGBland: Selecting Colors for Statistical Graphics
Statistical graphics are often augmented by the use of color coding information contained in some variable. When this involves the shading of areas (and not only points or lines) - e.g., as in bar plots, pie charts, mosaic displays or heatmaps - it is important that the colors are perceptually based and do not introduce optical illusions or systematic bias. Here, we discuss how the perceptually-based Hue-Chroma-Luminance (HCL) color space can be used for deriving suitable color palettes for coding categorical data (qualitative palettes) and numerical variables (sequential and diverging palettes).Series: Research Report Series / Department of Statistics and Mathematic
Design Guidelines for Agent Based Model Visualization
In the field of agent-based modeling (ABM), visualizations play an important role in identifying, communicating and understanding important behavior of the modeled phenomenon. However, many modelers tend to create ineffective visualizations of Agent Based Models (ABM) due to lack of experience with visual design. This paper provides ABM visualization design guidelines in order to improve visual design with ABM toolkits. These guidelines will assist the modeler in creating clear and understandable ABM visualizations. We begin by introducing a non-hierarchical categorization of ABM visualizations. This categorization serves as a starting point in the creation of an ABM visualization. We go on to present well-known design techniques in the context of ABM visualization. These techniques are based on Gestalt psychology, semiology of graphics, and scientific visualization. They improve the visualization design by facilitating specific tasks, and providing a common language to critique visualizations through the use of visual variables. Subsequently, we discuss the application of these design techniques to simplify, emphasize and explain an ABM visualization. Finally, we illustrate these guidelines using a simple redesign of a NetLogo ABM visualization. These guidelines can be used to inform the development of design tools that assist users in the creation of ABM visualizations.Visualization, Design, Graphics, Guidelines, Communication, Agent-Based Modeling
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