21 research outputs found
L-systems in Geometric Modeling
We show that parametric context-sensitive L-systems with affine geometry
interpretation provide a succinct description of some of the most fundamental
algorithms of geometric modeling of curves. Examples include the
Lane-Riesenfeld algorithm for generating B-splines, the de Casteljau algorithm
for generating Bezier curves, and their extensions to rational curves. Our
results generalize the previously reported geometric-modeling applications of
L-systems, which were limited to subdivision curves.Comment: In Proceedings DCFS 2010, arXiv:1008.127
A new method for generic three dimensional human face modelling for emotional bio-robots
Existing 3D human face modelling methods are confronted with difficulties in
applying flexible control over all facial features and generating a great number of
different face models. The gap between the existing methods and the requirements of
emotional bio-robots applications urges the creation of a generic 3D human face
model. This thesis focuses on proposing and developing two new methods involved
in the research of emotional bio-robots: face detection in complex background
images based on skin colour model and establishment of a generic 3D human face
model based on NURBS. The contributions of this thesis are:
A new skin colour based face detection method has been proposed and
developed. The new method consists of skin colour model for skin regions
detection and geometric rules for distinguishing faces from detected regions. By
comparing to other previous methods, the new method achieved better results of
detection rate of 86.15% and detection speed of 0.4-1.2 seconds without any
training datasets.
A generic 3D human face modelling method is proposed and developed. This
generic parametric face model has the abilities of flexible control over all facial
features and generating various face models for different applications. It includes:
The segmentation of a human face of 21 surface features. These surfaces have
34 boundary curves. This feature-based segmentation enables the independent
manipulation of different geometrical regions of human face.
The NURBS curve face model and NURBS surface face model. These two
models are built up based on cubic NURBS reverse computation. The
elements of the curve model and surface model can be manipulated to change
the appearances of the models by their parameters which are obtained by
NURBS reverse computation.
A new 3D human face modelling method has been proposed and implemented
based on bi-cubic NURBS through analysing the characteristic features and
boundary conditions of NURBS techniques. This model can be manipulated
through control points on the NURBS facial features to build any specific
face models for any kind of appearances and to simulate dynamic facial
expressions for various applications such as emotional bio-robots, aesthetic
surgery, films and games, and crime investigation and prevention, etc
Dagstuhl News January - December 2005
"Dagstuhl News" is a publication edited especially for the members of the Foundation "Informatikzentrum Schloss Dagstuhl" to thank them for their support. The News give a summary of the scientific work being done in Dagstuhl. Each Dagstuhl Seminar is presented by a small abstract describing the contents and scientific highlights of the seminar as well as the perspectives or challenges of the research topic
SVG 3D Graphical Presentation for Web-based Applications
Due to the rapid developments in the field of computer graphics and computer hardware, web-based applications are becoming more and more powerful, and the performance distance between web-based applications and desktop applications is increasingly closer. The Internet and the WWW have been widely used for delivering, processing, and publishing 3D data. There is increasingly demand for more and easier access to 3D content on the web. The better the browser experience, the more potential revenue that web-based content can generate for providers and others. The main focus of this thesis is on the design, develop and implementation of a new 3D generic modelling method based on Scalable Vector Graphics (SVG) for web-based applications. While the model is initialized using classical 3D graphics, the scene model is extended using SVG. A new algorithm to present 3D graphics with SVG is proposed. This includes the definition of a 3D scene in the framework, integration of 3D objects, cameras, transformations, light models and textures in a 3D scene, and the rendering of 3D objects on the web page, allowing the end-user to interactively manipulate objects on the web page. A new 3D graphics library for 3D geometric transformation and projection in the SVG GL is design and develop.
A set of primitives in the SVG GL, including triangle, sphere, cylinder, cone, etc. are designed and developed. A set of complex 3D models in the SVG GL, including extrusion, revolution, Bezier surface, and point clouds are designed and developed. The new Gouraud shading algorithm and new Phong Shading algorithm in the SVG GL are proposed, designed and developed. The algorithms can be used to generate smooth shading and create highlight for 3D models. The new texture mapping algorithms for the SVG GL oriented toward web-based 3D modelling applications are proposed, designed and developed. Texture mapping algorithms for different 3D objects such as triangle, plane, sphere, cylinder, cone, etc. will also be proposed, designed and developed. This constitutes a unique and significant contribution to the disciplines of web-based 3D modelling, as well as to the process of 3D model popularization