In this paper, we present a new method for detecting curvilinear structures in a gray-scale image. The concept of skeleton extraction is introduced to detect more general structures such as tapering structures. A skeleton is extracted from the Euclidean distance map that is constructed based on the edge map of an input image. Then, skeletal points are classified into three types (RIDGE, RAVINE ...

With this note, we would like present a method to compute the incompatibility operator in any system of curvilinear coordinates/components. The procedure is independent of the metric in the sense that the expression can be expressed by means of the basis vectors only, which are first defined as normal and tangent to the domain boundary and then extended to the whole domain. It is in some sense ...

We present an algorithm for efficiently computing ray intersections with multi-resolution global terrain which is partitioned by spheroidal height-augmented quadtrees. While previous methods support terrain defined on a Cartesian coordinate system, our methods support terrain defined on a two-parameter ellipsoidal coordinate system. This curvilinear system is necessary for an accurate model of ...

Details are given of a boundary-fitted mesh generation method for use in modelling free surface flow and water quality. A numerical method has been developed for generating conformal meshes for curvilinear polygonal and multiply-connected regions. The method is based on the Cauchy-Riemann conditions for the analytic function and is able to map a curvilinear polygonal region directly onto a regu...

In this work we introduce and perform a study on the multitime multi-objective fractional variational problem of minimizing a vector of quotients of path independent curvilinear integral functionals (MFP ) subject to certain partial differential equations (PDE) and/or partial differential inequations (PDI), using a geometrical language. The paper is organized as follows: §1 formulates a PDI&PDE...

We present a novel scheme to interactively visualize time-varying scalar fields defined on a curvilinear grid. We create a 3D warp texture that maps points in R into the grid coordinate system. At rendering time, the warping function is reconstructed at each fragment using tri-linear interpolation, and provides the 3D texture coordinates required to look up a scalar field value stored in a sepa...

This study examined the relationship between stressors at work and personal initiative (PI), one proactive concept of extra-role performance. Using a control theory framework to describe the stress process, the authors hypothesized that stressors should be positively related to PI. This departs from findings of negative relationships between stressors and other types of performance. Furthermore...

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...

where h is the avalanche thickness, Q is the depth averaged downslope volume flux and x is the curvilinear downslope coordinate. The source term s on the right-hand side of (2) is composed of the downslope component of gravitational acceleration, the Coulomb sliding friction with basal angle of friction δ and gradients of the basal topography height, b, above the curvilinear coordinate system. ...

In this paper, we describe a way to compute accurate bounds on Jacobian determinants of curvilinear polynomial finite elements. Our condition enables to guarantee that an element is geometrically valid, i.e., that its Jacobian determinant is strictly positive everywhere in its reference domain. It also provides an efficient way to measure the distortion of curvilinear elements. The key feature ...