Lower bounds on the generation of smooth bi-cubic surfaces imply that geometrically smooth (G) constructions need to satisfy conditions on the connectivity and layout. In particular, quadrilateral meshes of arbitrary topology can not in general be covered with G-connected Bézier patches of bi-degree 3 using the layout proposed in [ASC17]. This paper analyzes whether the pre-refinement of the in...

We describe a subdivision scheme that acts on control nodes that each carry a vector of values. Each vector defines partial derivatives, referred to as jets in the following and subdivision computes new jets from old jets. By default, the jets are automatically initialized from a design mesh. While the approach applies more generally, we consider here only a restricted class of design meshes, c...

Abstract. A well-documented problem of Catmull and Clark subdivision surfaces is that, in the neighborhood of extraordinary points, the curvature is unbounded and fluctuates. In fact, since one of the eigenvalues that determines elliptic shape is too small, the limit surface can have a saddle point when the designer’s input mesh suggests a convex shape. Here, we replace, near the extraordinary ...

A complete stability and convergence analysis is given for twoand three-level, piecewise Hermite bicubic orthogonal spline collocation, Laplacemodified and alternating-direction schemes for the approximate solution of linear parabolic problems on rectangles. It is shown that the schemes are unconditionally stable and of optimal-order accuracy in space and time.

A well-documented problem of Catmull and Clark subdivision is that, in the neighborhood of extraordinary point, the curvature is unbounded and fluctuates. In fact, since one of the eigenvalues that determines elliptic shape is too small, the limit surface can have a saddle point when the designer’s input mesh suggests a convex shape. Here, we replace, near the extraordinary point, CatmullClark ...

In this paper we present an approximation method of surfaces by a new type of splines, which we call fairness bicubic splines, from a given Lagrangian data set. An approximating problem of surface is obtained by minimizing a quadratic functional in a parametric space of bicubic splines. The existence and uniqueness of this problem are shown as long as a convergence result of the method is estab...

Historical document images are subject to intrinsic distortions such as background noise and bleed-through interference due to aging and extrinsic distortions such as displacement, uneven surfaces introduced during image acquisition procedure. In this paper, we propose a fully automatic restoration framework that corrects bleed-through distortion on double-sided handwritten historical document ...

Spatial resolution is a key parameter in many applications of image processing. In order to improve the spatial resolution we make use of super resolution algorithms. In this paper an SR image reconstruction algorithm is proposed using Integer wavelet transform (IWT) and Bit plane technique (BTP). The proposed method is analyzed in different color space transforms such as RGB, Ycbcr and CIELAB ...

Parallel phase-shifting digital holography (PPSDH) employing a polarization image sensor can suppress zero-order and twin-image noise through single exposure, achieve instantaneous measurement of complex-valued dynamic objects, have broad applications in the areas biomedicine, etc. To improve imaging resolution PPSDH, we propose an oversampled super-pixel reconstruction method, which be express...