Local, parallel analysis of shading in an image may be used to infer surface shape without o priori knowledge about the viewed scene. The following has been proven: Given a reasonable assumption about surface smoothness, local analysis of the second derivative of image intensity allows the image-plane component of surface orientation to be determined exactly, and a maximum-likelihood estimate o...

Imposing smoothness priors is a key idea of the top-ranked global stereo models. Recent progresses demonstrated the power of second order priors which are usually defined by either explicitly considering three-pixel neighborhoods, or implicitly using a so-called 3D-label for each pixel. In contrast to the traditional first-order priors which only prefer fronto-parallel surfaces, second-order pr...

A robust approach to recovery of shape from shading information is presented. Assuming uniform albedo and Lambertian surface for the imaging model, we first present methods for the estimation of illuminant direction and surface albedo. The illuminant azimuth is estimated by averaging local estimates. The illuminant elevation and surface albedo are estimated from image statistics. Using the esti...

The statistics of failure of the hydraulic-burst (HB) test were compared with those of the ball-on-ring (BOR) test. Polycrystalline Al2O3 tape-cast specimens, both square and circular, in two different sizes, were tested. Both the mean strengths and the Weibull moduli from the BOR tests were approximately twice the values from the HB tests. The area (volume) under stress is much larger for the ...

Via a random construction we establish necessary conditions for L(l) inequalities for certain families of operators arising in harmonic analysis. In particular we consider dilates of a convolution kernel with compactly supported Fourier transform, vector maximal functions acting on classes of entire functions of exponential type, and a characterization of Sobolev spaces by square functions and ...

We give direct approximation theorems for some linear operators in certain weighted spaces. The results are given in terms of some DitzianTotik moduli of smoothness.

Deformable models, originally proposed by Terzopoulos et al. (Artif. Intell. 36 (1988) 91) and Kass et al. (Int. J. Comput. Vision 1 (1988) 321) in 1988, have been widely used in medical image segmentation. However, they manifest two well-known limitations: the lack of an appropriate long-range force to drive the model surface towards the object boundary and poor performance at high curvature b...

We discuss G smoothness conditions for rectangular and triangular Gregory patches. We then incorporate these G conditions into a surface fitting algorithm. Knowledge of the patch type is inconsequential to the formulation of the G conditions, hence the term agnostic G Gregory surfaces. 2012 Elsevier Inc. All rights reserved.

We study the global smooth solution for the coupled Kuramoto-Sivanshinsky-KdV system in two-dimensional space. The model is proposed to describe the surface waves on multi-layered liquid films. The global solution is obtained for general initial data, using an a priori estimate for the nonlinear system, and the smoothness of such solution is established in t > 0.

Finite-element modelling is a standard way for simulation of soft tissue deformation. For proper modelling, triangular surface models must fulfil requirements of accuracy, smoothness, and conciseness. Several techniques proposed in the literature do not meet these requirements. In this paper we extend a new technique called SurfaceNets, which can create a globally smooth triangle mesh that reta...