This paper reports the design and implementation of an interactive and immersive environment (IIE) for tennis simulation. The presented design layout, named Tennis Space, provides the necessary immersive experience without overly restricting the player. To address the instability problem of real-time tracking of fast moving objects, a hybrid tracking solution integrating optical tracking and ultrasound-inertial tracking technologies is developed. An L-shaped IIE has been implemented for tennis simulation and has received positive feedback from users.

Virtual reconstruction of Tang Chang'an city needs more people's participation. To facilitate the collaboration among remote participants, a shared cyber venue is desired. This paper reports on a research effort that aims to develop a collaborative visualization environment over the internet. By integrating advanced visualization modules into a well established teleconferencing Grid platform, this environment provides participants more useful and reliable tools for the collaborative digital reconstruction. Based on a comprehensive discussion of visualization issues and shared applications over the Grid, this paper elaborates on how to render largescale polygonal models in real-time and how to efficiently reduce communication costs.

This paper describes a markerless method for automatically estimating animation parameters of an anatomy-based face model from a video sequence. The method is based upon an efficient tracking procedure which employs a linear subspace model of facial appearance. During the training phase of the tracking algorithm, a set of templates is computed from the subspace basis to alleviate the online computation. The efficient tracking algorithm establishes temporal correspondence of the face region by simultaneously determining both motion and appearance parameters. Using a set of key expressions of the actor together with corresponding animation parameters of the face model, we learn a linear relationship between facial animation parameters and appearance parameters. It allows us to efficiently estimate the animation parameters from appearance parameters provided by the tracker. We present experimental results performed on synthetic and live video sequences to demonstrate the effectiveness and efficiency of our method.

Multiresolution models provide a powerful tool for complex shape multiresolution editing. However, it is still hard and not intuitive to modify the overall shape of a model while preserving its details by manipulating its control points at lower resolution levels. A better control of deformations and a more intuitive interface should allow the user to control the deformation of a model by manipulating the model directly. This can be achieved by using variational modeling techniques. This paper presents a variational framework for multiresolution model design. The modeled shape is represented as a multiresolution B-spline curve or surface, which can be interactively deformed by direct user inputs. The focus of this paper is on handling multiresolution constraints and preserving surface details throughout the deformation process. To avoid smoothing out the details of the shape in variational modeling, we optimize the deformation energy alone instead of the total energy of the deformed shape. To accelerate the convergence of the iterative energy minimization process, a wavelet-based iterative method is used to compute the solution in a hierarchical fashion.