It is a challenge to provide a wide range of queries to database query systems for small mobile devices, such as the PDAs and cell phones. Currently, due to the physical and resource limitations of these devices, most reported database querying systems developed for them are only offering a small set of pre-determined queries for users to possibly pose. The above can be resolved by allowing fre...

We address the problem of recognizing 3D rigid freeform objects using dense range data when the objects can be imaged from arbitrary viewpoints and the objects vary in shape and complexity. We propose a multi-level matching strategy that employs shape spectral analysis and features derived from the COSMOS representations of free-form objects for fast and efficient recognition. We demonstrate th...

It has been shown recently that rigid or affine dynamics of curves defined by algebraic equations can be represented in terms of Riccati dynamics of possibly complex lines. In this work, we develop new Riccati equations in real variables for closed-bounded curves and new recursions on multiplicative scalars in the decomposition of the curve. A parameter identification scheme has also been propo...

Many applications, such as contour machining, rapid prototyping, and reverse engineering by laser scanner or coordinate measuring machine, involve sampling of free-from surfaces along section cuts by a family of parallel planes with equidistant spacing ∆ and common normal N. To ensure that such planar sections provide faithful descriptions of the shape of a surface, it is desirable to choose th...

We present a sufficient criterion for the Bernstein-Bezier (BB) form of a trivariate polynomial within a tetrahedron, such that the real zero contour of the polynomial defines a smooth and single sheeted algebraic surface patch. We call this an A-patch. We present algorithms to build a mesh of cubic A-patches to interpolate a given set of scattered point data in three dimensions, respecting the...

The Gauss map of a smooth doubly{curved surface characterizes the range of variation of the surface normal as an area on the unit sphere. An algorithm to approximate the Gauss map boundary to any desired accuracy is presented, in the context of a tensor{product polynomial surface patch, r(u;v) for (u; v) 2 0; 1 ] 0; 1 ]. Boundary segments of the Gauss map correspond to variations of the normal ...

This paper addresses the problem of integrating free-form surfaces in a constrained object reconstruction. The objects of interest here have both simple shaped surfaces (e.g. planes and quadrics) and free-from surfaces. The goal is to ensure a global optimization of the object shape where neighbourhood relationships between free-from surfaces and analytic surfaces are also satissed. The scheme ...

Deformation of 3D shapes usually requires the use of a deformation tool. The freeform deformation technique requires the use of a lattice of control point for deforming an object. This may require a synchronized movement of the lattice control points in order to obtain the desired effects. The axial deformation technique allows an object to be deformed by manipulating an axial curve. However, u...

Geometric matching in general is a difficult unsolved problem in computer vision. Fortunately, in many practical applications, some a priori knowledge exists which considerably simplifies the problem. In visual navigation, for example, the motion between successive positions is usually either small or approximately known, but a more precise registration is required for environment modeling. The...

Non-rigid image registration using free-form deformations (FFD) is a widely used technique in medical image registration. The balance between robustness and accuracy is controlled by the control point grid spacing and the amount of regularization. In this paper, we revisit the classic FFD registration approach and propose a sparse representation for FFDs using the principles of compressed sensi...