Inference of 3-D shape from 2-D contours in a single image is an important problem in machine vision. Often, techniques to solve this problem examine each surface in the scene separately whereas our perception of their shapes clearly depends on the interplay between them as well. In this paper, we describe a technique that attempts to recover the shapes of all the surfaces of an object simultan...

We prove that the scale map of the .zero-crossings of almost all signals filtered by a gaussian of variable size determines the signal uniquely, up to a constant scaling. Exceptions are signals that are antisymmetric about all their zeros (for instance infinitely periodic gratings). Our proof provides a method for reconstructing almost all signals from knowledge of how the zero-crossing contour...

In the last few years, it has become apparent that traditional wavelet-based image processing algorithms and models have significant shortcomings in their treatment of edge contours. The standard modeling paradigm exploits the fact that wavelet coefficients representing smooth regions in images tend to have small magnitude, and that the multiscale nature of the wavelet transform implies that th...

1 ACTIVE CONTOURS WITHOUT EDGES Chan and Vese [1] proposed an approximation for the MS segmentation model by following the level-set based curve evolution formulation [2, 3]. Level sets provide an implicit contour representation where an evolving curve is represented with the zerolevel line of a level set function (Figure 1). The basic aim of Chan and Vese (CV) model is to partition a given ima...

Level set methods are the numerical techniques for tracking interfaces and shapes. They have been successfully used in image segmentation. A new variational level set evolving algorithm without re-initialization is presented in this paper. It consists of an internal energy term that penalizes deviations of the level set function from a signed distance function, and an external energy term that ...

New supplementary conditions are proposed for the two-dimensional Neumann–Kelvin problem describing the forward motion of a surface-piercing body. They lead to the absence of waves behind the body, and hence, the wave resistance is equal to zero. Moreover, for the body with symmetry about vertical axis the total resistance to the forward motion (the sum of wave and spray resistance) also vanish...

In our feature-based matching approach, zero-crossings are matched and represented in 3-D object space by a sequence of densely spaced points. These spatial curves form the basis for reconstructing the surface. Since edges are likely to correspond to object boundaries, the 3-D curves also serve as an important input for object recognition. In this paper we address the problem of segmenting the ...

when flow passes over the tube bundles, energy of flow transfers to the tubes. the fluid induced vibrations (fiv) imposed on the tubes is one of the important problems in analyzing the tube bundles and causes several problems. in this work, first, laminar flow around circular cylinder asymmetrically in a channel is simulated. the reynolds number is 20 and 100. the lift forces to tube are not ze...