This paper describes a new method for extracting facial components from a color image using cooperative active nets with global constraints. We utilize an active net model which is a region extraction method based on energy minimization principle. Each net deforms with its own energy being minimized and the position of the nets are controlled by minimizing an additional energy de ned by global ...

We explore the minimum energy configurations of repelling particles distributed over n possible locations forming a toric grid. We conjecture that the most energy-efficient way to distribute n/2 particles over this space is to place them in a checkerboard pattern. Numerical experiments validate this conjecture for reasonable choices of the repelling force. In the present paper, we prove this co...

In this paper, we present a vector spline technique for vector field reconstruction. These vector splines are based on an energy minimization functional, which involves the divergence and the rotational fields of the approximated vector. This technique can be used to determine the underlying coordinate transformation in image mapping.

It is possible to move, split, merge, and mix liquids in micro fluidic devices by applying spatially varying electric fields that effectively change the surface tension at specific spatial locations. The phenomena is brought about by a competition between surface tension effects (that cause the droplet to bead up because it has been placed on a hydrophobic surface) and electrical forces in the ...

The term RNA folding is often used synonymously with the prediction of equilibrium structures. Yet many RNAs function thanks to their ability to undergo structural changes. In this contribution we present a systematic overview of existing approaches to the prediction of RNA folding kinetics, and in particular discuss the strengths and limitations of each method.

Traditionally, vision systems have largely relied upon the object boundaries extracted from images to accomplish recognition. Most contour detection algorithms, however, suffer from the fact that the extracted object boundaries are usually broken and incomplete due to poor imaging conditions and/or occlusions. In this paper, we describe an algorithm to perform curvilinear grouping of image edge...

A 3D head modeling method from a sequence of 2D images is described. The views from which the input images are acquired are not calibrated. Therefore, an auto-calibration method for a sequence of images with small rotations and translation is developed. For this purpose, we have modified an already existing auto-calibration algorithm to incorporate known aspect ratio and skew values to make it ...

In this paper we present the results of computer searches using a variation of an energy minimization algorithm used by Kottwitz for finding good spherical codes. We prove that exact codes exist by representing the inner products between the vectors as algebraic numbers. For selected interesting cases, we include detailed discussion of the configurations. Of particular interest are the 20-point...

The present work is concerned with the development of a new algorithm for determination of the equilibrium composition of gaseous detonations. The elements balance equations, and the second law of thermodynamics (i.e., the minimization of the Gibbs free energy of products), are used to determine the equilibrium composition of the detonation products. To minimize the Gibbs free energy with tradi...

We propose a biologically motivated method for creating animations of opening flowers. We simulate the development of petals based on the observation that flower opening is mainly caused by cell expansion. We use an elastic triangular mesh to represent a petal and emulate its growth by developing each triangular region. Our simulation process consists of two steps. The system first grows each t...