2003
https://diglib.eg.org:443/handle/10.2312/8114
2024-03-29T04:47:27ZA Head Model with Anatomical Structure for Facial Modeling and Animation
https://diglib.eg.org:443/handle/10.2312/14684
A Head Model with Anatomical Structure for Facial Modeling and Animation
Kähler, Kolja
In this dissertation, I describe a virtual head model with anatomical structure. The
model is animated in a physics-based manner by use of muscle contractions that in
turn cause skin deformations; the simulation is ef cient enough to achieve real-time
frame rates on current PC hardware. Construction of head models is eased in my
approach by deriving new models from a prototype, employing a deformation method
that reshapes the complete virtual head structure. Without additional modeling tasks,
this results in an immediately animatable model. The general deformation method
allows for several applications such as adaptation to individual scan data for creation
of animated head models of real persons. The basis for the deformation method is a
set of facial feature points, which leads to other interesting uses when this set is chosen
according to an anthropometric standard set of facial landmarks: I present algorithms
for simulation of human head growth and reconstruction of a face from a skull.
2003-01-01T00:00:00ZEfficient Acquisition, Representation, and Rendering of Light Fields
https://diglib.eg.org:443/handle/10.2312/8162
Efficient Acquisition, Representation, and Rendering of Light Fields
Schirmacher, Hartmut
In this thesis we discuss the representation of three-dimensional scenes using image data (image-based rendering), and more precisely the so-called light field approach. We start with an up-to-date survey on previous work in this young field of research. Then we propose a light field representation based on image data and additional per-pixel depth values. This enables us to reconstruct arbitrary views of the scene in an efficient way and with high quality. Furthermore, we can use the same representation to determine optimal reference views during the acquisition of a light field. We further present the so-called free form parameterization, which allows for a relatively free placement of reference views. Finally, we demonstrate a prototype of the Lumi-Shelf system, which acquires, transmits, and renders the light field of a dynamic scene at multiple frames per second.
2003-12-16T00:00:00ZAlves dos Santos, Luiz: Asymmetric and Adaptive Conference Systems for Enabling Computer-Supported Mobile Activities
https://diglib.eg.org:443/handle/10.2312/8161
Alves dos Santos, Luiz: Asymmetric and Adaptive Conference Systems for Enabling Computer-Supported Mobile Activities
Alves dos Santos, Luiz Manoel
This work was conducted at the Darmstadt University of Technology, essentially between
1998 and 2002. Before and during this period, I was working at the INI-GraphicsNet,
Darmstadt, first in the Zentrum für Graphische Datenverarbeitung e.V., and then later at the
Fraunhofer-Institut für Graphische Datenverarbeitung (IGD), as a researcher. This thesis
addresses the investigations and results achieved during my work at these organizations.
My initial development projects in the area of mobile computing were very challenging due
to the immense constraints posed by the then incipient hardware and wireless network
infrastructures, and similarly overwhelming due to the desire to employ those fascinating
appliances by all means possible. The endeavour to keep the respective application systems
in a course of continuous improvement (i.e., with richer media presentation and
“interactiveness”), and at the same astonishing pace as the technological evolutions, was both
demanding and rewarding; however, it turned out to be a questionable procedure. After
several prototype demonstrations and observations, there came a turning point, following the
acknowledgement that, for application cases involving user mobility, the supporting tool is
appraised significantly on the basis of its adequacy for the usage conditions and its flexibility
to adapt to changing requirements and to any platform specification or resource availability.
The circumstances of a mobile use (e.g., outdoor, on the move, in confined places) require
new approaches in application system development and create a high demand for specialized,
task-oriented system features. Any service being offered has to be able to account for, adjust
itself, and be responsive to the increasing and unpredictable diversity of prospective users
and their usage environments. The achievement of this attribute is even more challenging
when the service should be a basis for a digitally mediated human-to-human communication
process involving all kinds of diversity between the individual partners and technical
arrangements.
In this thesis work, proposals and innovative solutions to these challenges have been
investigated and implemented, and are presented in this report. Some contributions of this
work are: an adaptive conference system for heterogeneous environments, tools to assess,
distribute, and respond to User Profiles at both the individual and collective level; adaptive,
flexible individual interaction modes and media that are nevertheless consistent for a
collaborative work; and mechanisms for remote awareness (of constraints) for structuring
interaction. However, above any technological advances, the major research challenge was
concerned with the human factor and the achievement of an effective integration of a
supporting tool in their daily activities and lives.
2003-01-01T00:00:00ZEfficient, Image-Based Appearance Acquisitionof Real-World Objects
https://diglib.eg.org:443/handle/10.2312/8160
Efficient, Image-Based Appearance Acquisitionof Real-World Objects
Lensch, Hendrik Peter Asmus
Two ingredients are necessary to synthesize realistic images: an accurate rendering algorithm and, equally important, high-quality models in terms of geometry and reflection properties. In this dissertation we focus on capturing the appearance of real world objects. The acquired model must represent both the geometry and the reflection properties of the object in order to create new views of the object with novel illumination. Starting from scanned 3D geometry, we measure the reflection properties (BRDF) of the object from images taken under known viewing and lighting conditions. The BRDF measurement require only a small number of input images and is made even more efficient by a view planning algorithm. In particular, we propose algorithms for efficient image-to-geometry registration, and an image-based measurement technique to reconstruct spatially varying materials from a sparse set of images using a point light source. Moreover, we present a view planning algorithm that calculates camera and light source positions for optimal quality and efficiency of the measurement process. Relightable models of real-world objects are requested in various fields such as movie production, e-commerce, digital libraries, and virtual heritage.
2003-12-15T00:00:00Z