To perceive the real motion of objects in the world while moving the eyes, retinal motion signals must be compensated by information about eye movements. Here we study when this compensation takes place in the course of visual processing, and whether uncompensated motion signals are ever available. We used a paradigm based on asymmetry in motion detection: Fast-moving objects are found easier a...

The method of moving frames provides powerful geometrical tools for the analysis of smoothly varying frame fields. However, in the face of missing measurements, a reconstruction problem arises, one that is largely unexplored for 3D frame fields. Here we consider the particular example of reconstructing impaired cardiac diffusion magnetic resonance imaging (dMRI) data. We combine moving frame an...

We study the electromagnetic fields of an arbitrarily moving charged particle and the radiation reaction on the charged particle using a novel approach. We first show that the fields of an arbitrarily moving charged particle in an inertial frame can be related in a simple manner to the fields of a uniformly accelerated charged particle in its rest frame. Since the latter field is static and eas...

We present a formalism well adapted to the numerical study of the encounter of an ordinary main sequence star with a massive black hole. Symmetry considerations , the use of a well adapted moving grid and a well adapted moving frame along with integration of the partial differential equations by means of pseudo-spectral methods result in a very powerful and accurate tool. The hydro-dynamical eq...

The detection of moving people is an important task for video surveillance systems. This paper presents a motion segmentation algorithm for detecting people moving in indoor environments. The proposed algorithm works with mobile cameras and it is composed of two main parts. In the first part, a frame-by-frame procedure is applied to compute the difference image, and a neural network is used to ...

This paper focuses on key steps in video analysis i.e. Detection of moving objects of interest and tracking of such objects from frame to frame. The object shape representations commonly employed for tracking are first reviewed and the criterion of feature Selection for tracking is discussed. Various object detection and tracking approaches are compared and analyzed.

This paper proposes an accurate and fast background subtraction technique for object tracking in still camera videos. Regions of motion in a frame are first estimated by comparing the current frame to a previous one. A samplingresampling based Bayesian learning technique is then used on the estimated regions to perform background subtraction and accurately determine the exact pixels which corre...

This paper presents three non-linear observers for three examples of engineering interest: a nonholonomic car, a chemical reactor, and an inertial navigation system. For each example, the design is based on physical symmetries. This motivates the theoretical development of invariant observers, i.e, symmetry-preserving observers. We consider an observer to consist of a copy of the system equatio...

In this paper we study a fully relativistic model of a two-dimensional hard-disk gas. This model avoids the general problems associated with relativistic particle collisions and is therefore an ideal system to study relativistic effects in statistical thermodynamics. We study this model using molecular-dynamics simulation, concentrating on the velocity distribution functions. We obtain results ...

We study the boundedness of the Dirichlet energy of moving frames associated to immersions of torus in the Poincaré upper half-space. The frame energy functional is closely related to the Willmore energy and also to the conformal structure on the underlying torus. A lower bound for the frame energy is established. M.S.C. 2010: 30F45, 53A30, 53A35, 53C42.