Incompressible stationary flows of ideal plasma are observed. By introduction of curvilinear system of coordinates in which streamlines and magnetic force lines form a family of coordinate surfaces, MHD equations are partially integrated and brought to a certain convenient form. It is demonstrated that the admissible group of Bogoyavlenskij’s symmetry transformations [1] performs as a scaling t...

In this report we have used projectivity theory to model the process of structured light scanning for 3D robot vision. The projectivity formalism is used to derive a 4x3 transformation matrix that converts points in the image plane into their corresponding 3D world coordinates. Calibration of the scanner consists of computing the coefficient of this matrix by showing to the system a set of line...

During visually guided movement, visual coordinates of target location must be transformed into coordinates appropriate for movement. To investigate the representation of this visuomotor coordinate transformation, we examined changes in pointing behavior induced by a local visuomotor remapping. The visual feedback of finger position was limited to one location within the workspace, at which a d...

Actually, there is first a small technical issue of mapping between texture coodinates, which might be defined on any arbitrary rectangle in 2D, and actual texel coordinates (e.g. numbers between 0 and 512 for a 512 × 512 texture image). This is handled as usual by a windowing transform, which can be conveniently represented with a transformation matrix: as mentioned last time, OpenGL even prov...

Transformations between group coordinates of three–dimensional conformal σ–models in the flat background and their flat, i.e. Riemannian coordinates enable to find general dilaton fields for three–dimensional flat σ–models. By the Poisson–Lie transformation we can get dilatons for the dual σ–models in a curved background. Unfortunately, in some cases the dilatons depend on inadmissible auxiliar...

The transformation of the eikonal equation from depth coordinates (z, x) into verticaltraveltime coordinates (τ ,ξ ) enables the computation of reflections traveltimes independent of depth-mapping. This separation allows the focusing and mapping steps to be performed sequentially even in the presence of complex velocity functions, that otherwise would “require” depth migration. The traveltimes ...

The embryonic development of the optic nerve of the zebrafish, Brachydanio rerio, was studied by three-dimensional computer reconstruction from serial section electron micrographs. Growing fibers from retinal ganglion cells had growth cones in contact with more mature fibers from adjacent cell bodies. In the observed growth pattern, the optic fibers immediately behind the eye were ordered in su...

An inversion formula was developed by Bukhgeim and Kazantsev for attenuated fan-beam projections [Russian Academy of Science Siberian Branch: The Sobolev Institute of Mathematics (2002)]. The inversion formula was obtained by relating the attenuated fan-beam projections to unattenuated fan-beam projections and by trickily processing the unattenuated fan-beam projections. We show in this paper t...

This paper aims to address the regulation problem for the unicycle model while guaranteeing prescribed performance. Different controllers based either on polar coordinates or time-varying laws are proposed. The main contribution is the combination of the standard control laws that allow to achieve posture regulation for the unicycle, with the prescribed performance control technique that impose...

This paper proposes the Top-View Transformation Model for image coordinate transformation, which involves transforming a perspective projection image into its corresponding bird's eye vision. A fitting parameters searching algorithm estimates the parameters that are used to transform the coordinates from the source image. Using this approach, it is not necessary to provide any interior and exte...