Boundedness properties for pseudodifferential operators with symbols in the bilinear Hörmander classes of sufficiently negative order are proved. The results are obtained in the scale of Lebesgue spaces, and in some cases, end-point estimates involving weak-type spaces and BMO are provided as well. From the Lebesgue space estimates, Sobolev ones are then easily obtained using functional calculu...

Local and global approaches to digital image correlation are compared when the displacement interpolation is based upon bilinear shape functions (i.e., with fournode quadrilaterals). The resolution in terms of displacements and strains associated with both techniques are evaluated a priori and validated a posteriori by using series of images of real experiments. It is shown that global approach...

Stabilized finite element formulation for the Reissner-Mindlin plate model is considered. Physical interpretation for the stabilization procedure for low order elements is established. Explicit interpolation functions for linear and bilinear stabilized MITC elements are derived. Some numerical examples including buckling and frequency analyses are presented. Copyright c © 2000 John Wiley & Sons...

We propose a new multiframe algorithm to enhance the spatial resolution of frames in video sequences. Our technique specifically accounts for the possibility that motion estimation will be inaccurate and compensates for these inaccuracies. Experiments comparing our results with other methods show that our multiframe enhancement algorithm yields perceptibly sharper enhanced images with significa...

Assumptions about image continuity lead to oversmoothed edges in common image interpolation algorithms. A wavelet-based interpolation method that imposes no continuity constraints is introduced. The algorithm estimates the regularity of edges by measuring the decay of wavelet transform coefficients across scales and preserves the underlying regularity by extrapolating a new subband to be used i...

An eecient compression/decompression scheme is described for the compression of image data gathered for engineering use on Mars Pathhnder: the image is pixel-averaged at diierent downsampling factors horizontally and vertically (step 1), JPEG compressed (step 2), JPEG decompressed (step 3) and interpolated to its original size (step 4). Optimal interpolation lters (step 4) are derived to minimi...

This paper presents an advance on image interpolation based on ant colony algorithm (AACA) for high resolution image scaling. The difference between the proposed algorithm and the previously proposed optimization of bilinear interpolation based on ant colony algorithm (OBACA) is that AACA uses global weighting, whereas OBACA uses local weighting scheme. The strength of the proposed global weigh...

A characterization and classification of the isosurfaces of trilinear functions is presented. Based upon these results, a new algorithm for computing a triangular mesh approximation to isosurfaces for data given on a 3D rectilinear grid is presented. The original marching cubes algorithm is based upon linear interpolation along edges of the voxels. The asymptotic decider method is based upon bi...

Abstract We analyse the interpolation properties of two-dimensional and three-dimensional low-order virtual element (VE) face edge spaces, which generalize Nédélec Raviart–Thomas polynomials to polygonal-polyhedral meshes. Moreover, we investigate stability associated $L^2$-discrete bilinear forms, typically appear in VE discretization problems electromagnetism.

The purpose of this paper is to describe a unified approach to proving vector-valued inequalities without relying on the full strength of weighted theory. Our applications include the Fefferman-Stein and Cordoba-Fefferman inequalities, as well as the vector-valued Carleson operator. Using this approach we also produce a proof of the boundedness of the classical bi-parameter multiplier operators...