The completion of interrupted lines or the enhancement of ow-like structures is a challenging task in computer vision, human vision, and image processing. We address this problem by presenting a multiscale method in which a nonlinear diiusion lter is steered by the so-called interest operator (second-moment matrix, structure tensor). An m-dimensional formulation of this method is analysed with ...

the purpose of this letter is to revisit the nonlinear reaction-diusion modelin porous catalysts when reaction term is fractional function of the concen-tration distribution of the reactant. this model, which originates also in uidand solute transport in soft tissues and microvessels, has been recently givenanalytical solution in terms of taylors series for dierent family of reactionterms. we...

A non-oscillatory numerical scheme based on a general solution of unsteady advection–di usion equations is presented. A general solution for initial value problems of linear two-dimensional unsteady advection–di usion equations is obtained using the spectral method. The resulting numerical scheme is explicit with respect to time, and ful lls the Patankar’s positive coe cients condition for any ...

A multigrid preconditioned conjugate gradient algorithm is introduced into a semiconductor device modeling code DANCIR This code simulates a wide variety of semiconductor devices by numerically solving the drift di usion equations The most time consuming aspect of the simulation is the solution of three linear systems within each iteration of the Gummel method The original version of DANCIR use...

Error di usion halftoning is a popular method of producing frequency modulated (FM) halftones. In FM halftoning the dot size and shape is xed (equal to one pixel) and the dot frequency is varied in accordance to the graylevel values of the underlying grayscale image. We generalize error di usion to produce FM halftones with user controlled dot size and shape using block quantization and a block...

We investigate the relative importance of di®usion and jumps in a new jump di®usion model for asset returns. In contrast to the standard modelling of jumps for asset returns, the jump component of our process can display ̄nite or in ̄nite activity, and ̄nite or in ̄nite variation. Empirical investigations of time series indicate that index dynamics are essentially devoid of a di®usion component, ...

Di€usion and convection coecients of the aerated ̄ow in a hydraulic jump are estimated in the framework of an optimal control problem. The speci®c gravity of air±water mixture is governed by a steady state convection di€usion partial di€erential equation. The governing equation includes the di€usion coecient and the convection coecient, which are taken as the control variables to minimize a ...

Image halftoning converts a high-resolution image to a low-resolution image, e.g. an 8-bit grayscale image to a binary image, for printing and display. Conventional error di usion halftoning produces worms and other objectionable artifacts. Tone Dependent error di usion (Li and Allebach) helps reduce these artifacts by controlling di usion of quantization errors based on the input graylevel val...

Introduction In this paper we consider cell centered nite di erence approximations for second order convection di usion equations of divergence type Our goal is to construct nite di erence methods of second order of approximation that satisfy the discrete maximum principle The error estimates are in the discrete Sobolev spaces associated with the considered boundary value problem Approximation ...

|The error di usion algorithm for digital halftoning is equivalent in form to a noise-shaping feedback coder, a class of delta-sigma modulator. The white noise assumption of the quantizer error is known to be false; in fact, the quantizer error is seen to be highly correlated with the input image. To account for this correlation, we use a gain model for the quantizer. This model accurately pred...