Image processing is playing a vital role in all fields like satellite, medical, telecommunication, and missile. Hyper spectral images show similar statistical properties to natural grayscale or color photographic images. HSI (Hyper Spectral Image) are a more challenging area because of high spectral bands and dimensionality. As well as it is very easy to learn. It will be used to identify the p...

This paper is concerned with partial regularity for weak solutions to nonlinear sub-elliptic systems related to Hörmander’s vector fields. The method of A-harmonic approximation introduced by Simon and developed by Duzaar and Grotowski is adapted to our context, and then a Caccioppoli-type inequality and partial regularity with optimal local Hölder exponent for gradients of weak solutions to th...

On the Earth and in its neighborhood, spherical harmonic analysis and synthesis are standard mathematical procedures for scalar, vector and tensor fields. However, with the advent of multiresolution applications, additional considerations about convolution filtering with decimation and dilation are required. As global applications often imply discrete observations on regular grids, computationa...

We give an elementary introduction to CR and pseudohermitian geometry, starting from H. Lewy’s legacy (cf. [20]) i.e. tangential Cauchy-Riemann equations on the boundary of the Siegel domain. In this context we describe fundamental objects, such as contact structures, Levi forms, the Tanaka-Webster connection and the Fefferman metric (cf. e.g. [4]). Also naturally arising Hörmander systems of v...

In this paper, we propose a new quadrilateral remeshing method for manifolds of arbitrary genus that is at once general, flexible, and efficient. Our technique is based on the use of smooth harmonic scalar fields defined over the mesh. Given such a field, we compute its gradient field and a second vector field that is everywhere orthogonal to the gradient. We then trace integral lines through t...

Harmonic maps between Riemannian manifolds are maps which extremize a certain natural energy functional; they appear in particle physics as nonlinear sigma models. Their infinitesimal deformations are called Jacobi fields. It is important to know whether the Jacobi fields along the harmonic maps between given Riemannian manifolds are integrable, i.e., arise from genuine variations through harmo...

Using the characterization of last multipliers as solutions of the Liouville equation of transport, new results in this approach of ODE are given by obtaining several new characterizations e.g. in terms of Witten and Marsden differentials. Applications to Hamiltonian vector fields on Poisson manifolds and vector fields on Riemannian manifolds are presented. In the Poisson case the unimodular br...