This paper presents a generic method for addressing the issue of 3D model-based head pose estimation. The method proposed relies on the downhill simplex optimization method and on the combination of motion and texture features. A proper initialization based on a block matching procedure associated with 3D/2D matching depending on texture and optical flow information leads to an accurate recover...

A methodology for the concurrent optimization of beam orientations and beam weights in conformal radiotherapy treatment planning has been developed and tested on a cohort of five patients. The algorithm is based on a beam-weight optimization scheme with a downhill simplex optimization engine. The use of random voxels in the dose calculation provides much of the required speed up in the optimiza...

This paper compares three different global indirect approaches for solving the problem of finding optimal trajectories for low thrust spacecraft. The three methods tested were downhill simplex, genetic algorithms and simulated annealing. Two problems are analyzed. The first is a planar low thrust problem. This is the problem of finding a minimum time trajectory from Earth to Mars orbit using a ...

This paper proposes a new design strategy for optimizing MRI pulse sequences for T1 relaxometry. The design strategy optimizes the pulse sequence parameters to minimize the maximum variance of unbiased T1 estimates over a range of T1 values using the Cramér-Rao bound. In contrast to prior sequences optimized for a single nominal T1 value, the optimized sequence using our bound-based strategy ac...

This paper addresses the issue of computer vision-based face motion capture as an alternative to physical sensor-based technologies. The proposed method combines deformable template-based tracking of mouth and eyes in arbitrary video sequences with a single speaking person with a global 3D head pose estimation procedure yielding robust initializations. Mathematical principles underlying deforma...

This paper is an overview of a method recently published in a biomedical journal (IEEE Transactions on Biomedical Engineering1). The method is based on an optimisation technique called “evolutionary strategy” and it has been designed to estimate the parameters of a complex 15-D respiration model. This model is adaptable to account for patient’s specificities. The aim of the optimisation algorit...