717 research outputs found
BiopSym: a simulator for enhanced learning of ultrasound-guided prostate biopsy
This paper describes a simulator of ultrasound-guided prostate biopsies for
cancer diagnosis. When performing biopsy series, the clinician has to move the
ultrasound probe and to mentally integrate the real-time bi-dimensional images
into a three-dimensional (3D) representation of the anatomical environment.
Such a 3D representation is necessary to sample regularly the prostate in order
to maximize the probability of detecting a cancer if any. To make the training
of young physicians easier and faster we developed a simulator that combines
images computed from three-dimensional ultrasound recorded data to haptic
feedback. The paper presents the first version of this simulator
Imperfection for Realistic Image Synthesis
The precision of image synthesis techniques for rendering naturalistic scenes often works contrary to the realism of the everyday world. Pristine, crystalline, uniform and perfect may describe the most idealized computer images: the surfaces are smooth, neat and crisp in appearance. Efforts to produce realism have recently focused on light and the interaction of light with surfaces. The radiosity methods have shown that proper treatment of light is often critical to the proper visual effect in an image. Even the best of these images is nearly surrealistic in its precision, and thus belies its synthetic origins
Video conferencing: an effective solution to long distance student placement support?
Background Within many health related degree programmes, students receive support during placements via visiting tutors. Literature discusses the importance of this support but economic and environmental arguments indicate a need for alternatives to supporting a student in situ. This project investigated the logistics of and perceptions towards using video conferencing as a means of providing this support. Methods A pilot project was undertaken in which an in situ, support meeting was replaced with a meeting via video link. All participants completed evaluative questionnaires and students attended a follow up focus group in order to explore responses in more depth. Results and discussion Use of the medium identified key logistical hurdles in implementing technology into existing support systems. All participants expressed enthusiasm for the medium with educators expressing a preference. Students identified concerns over the use of this medium for failing placements but could not identify why. As a result of evaluation, this project has raised a number of questions relating to the fitness for purpose of video conferencing in this context. Conclusion Future research aims to respond to the questions raised in evaluating the value and purpose of placement support and the nature of conversations via the video conferencing medium
Extending the range of facial types
We describe, in case study form, techniques to extend the range of facial types and movement using a parametric facial animation system originally developed to model and control synthetic 3D faces limited to a normal range of human shape and motion. These techniques have allowed us to create a single authoring system that can create and animate a wide range of facial types that range from realistic, stylized, cartoon-like, or a combination thereof, all from the same control system. Additionally we describe image processing and 3D deformation tools that allow for a greater range of facial types and facial animation output
3D Face Synthesis with KINECT
This work describes the process of face synthesis by image morphing from less expensive 3D sensors such as KINECT that are prone to sensor noise. Its main aim is to create a useful face database for future face recognition studies.Peer reviewe
Autonomous Secondary Gaze Behaviours
In this paper we describe secondary behaviour, this is behaviour that is generated autonomously for an avatar. The user will control various aspects of the avatars behaviour but a truly expressive avatar must produce more complex behaviour than a user could specify in real time. Secondary behaviour provides some of this expressive behaviour autonomously. However, though it is produced autonomously it must produce behaviour that is appropriate to the actions that the user is controlling (the primary behaviour) and it must produce behaviour that corresponds to what the user wants. We describe an architecture which achieves these to aims by tagging the primary behaviour
with messages to be sent to the secondary behaviour and by allowing the user to design various aspects of the secondary behaviour before starting to use the avatar. We have implemented this general architecture in a system which adds gaze behaviour to user designed actions
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Parametric Representations of Facial Expressions on PDE-Based Surfaces
NoParameterisation of facial expressions on PDE surface
representations of human faces are presented in this
work. Taking advantage of the boundary-value approach
inherent to Bloor-Wilson PDE method, facial expressions
are achieved by manipulating the original boundary curves.
Such curves are responsible for generating a surface representation
of a human face in its neutral configuration,
so that regions on these curves represent a given facial
expression in a fast and realistic manner. Additionally, the
parameterisation proposed here is carried out by applying
different mathematical transformations to the affected
curves according to the corresponding facial expression.
Full analytic expressions parameterising some of the most
common facial expressions such as smiling and eyebrow
raising are in this work. Some graphical examples of these
facial expressions are used to illustrate the results obtained
using Bloor-Wilson PDE method as the foundations of the
parameterisation scheme proposed here. Thus, it is shown
that an efficient, intuitive and realistic parameterisation of
facial expressions is attainable using Bloor-Wilson PDE
method in along with a suitable mathematical expression
Improvements on a simple muscle-based 3D face for realistic facial expressions
Facial expressions play an important role in face-to-face communication. With the development of personal computers capable of rendering high quality graphics, computer facial animation has produced more and more realistic facial expressions to enrich human-computer communication. In this paper, we present a simple muscle-based 3D face model that can produce realistic facial expressions in real time. We extend Waters' (1987) muscle model to generate bulges and wrinkles and to improve the combination of multiple muscle actions. In addition, we present techniques to reduce the computation burden on the muscle mode
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